diff -ru4NwbB libpng-1.5.6/Makefile.am libpng-1.5.7/Makefile.am
--- libpng-1.5.6/Makefile.am 2011-11-02 22:42:58.022435114 -0500
+++ libpng-1.5.7/Makefile.am 2011-12-15 09:45:40.090994153 -0600
@@ -11,15 +11,19 @@
# AUTOMAKE_OPTIONS = foreign color-tests
AUTOMAKE_OPTIONS = foreign
# test programs - run on make check, make distcheck
-check_PROGRAMS= pngtest pngvalid
+TESTS_ENVIRONMENT= srcdir=$(srcdir)
+check_PROGRAMS= pngtest
pngtest_SOURCES = pngtest.c
pngtest_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
-pngvalid_SOURCES = pngvalid.c
+TESTS = test-pngtest.sh
+
+# Only do the following if the contrib directory is present.
+check_PROGRAMS+= pngvalid
+pngvalid_SOURCES = contrib/libtests/pngvalid.c
pngvalid_LDADD = libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@.la
-TESTS = test-pngtest.sh test-pngvalid-simple.sh test-pngvalid-full.sh
-TESTS_ENVIRONMENT= srcdir=$(srcdir)
+TESTS += test-pngvalid-simple.sh test-pngvalid-full.sh
# man pages
dist_man_MANS= libpng.3 libpngpf.3 png.5
@@ -35,8 +39,12 @@
pngget.c pngmem.c pngpread.c pngread.c pngrio.c pngrtran.c pngrutil.c\
pngset.c pngtrans.c pngwio.c pngwrite.c pngwtran.c pngwutil.c\
png.h pngconf.h pngdebug.h pnginfo.h pngpriv.h pngstruct.h
+if PNG_ARM_NEON
+libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES += arm/filter_neon.S
+endif
+
nodist_libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES = pnglibconf.h
libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_CPPFLAGS = @LIBPNG_DEFINES@
@@ -121,9 +129,9 @@
# The following is necessary to ensure that the local pnglibconf.h is used, not
# an installed one (this can happen immediately after on a clean system if
# 'make test' is the first thing the user does.)
-pngvalid.o pngtest.o: pnglibconf.h
+contrib/libtests/pngvalid.o pngtest.o: pnglibconf.h
# We must use -DPNG_NO_USE_READ_MACROS here even when the library may actually
# be built with PNG_USE_READ_MACROS; this prevents the read macros from
# interfering with the symbol file format.
@@ -137,19 +145,20 @@
test -d scripts || mkdir scripts
echo '#include "$<"' >dfn.c
$(DFNCPP) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) @LIBPNG_DEFINES@\
$(CPPFLAGS) $(SYMBOL_CFLAGS) dfn.c > dfn1.out
- $(SED) -n -e 's|^.*PNG_DEFN_MAGIC-\(.*\)-PNG_DEFN_END.*$$|\1|p'\
+ $(SED) -n -e 's|^.*PNG_DEFN_MAGIC *-\(.*\)- *PNG_DEFN_END.*$$|\1|p'\
dfn1.out >dfn2.out
- $(SED) -e 's| *@@@ *||g' -e 's| *$$||' dfn2.out >dfn3.out
+ $(SED) -e 's| *PNG_JOIN *||g' -e 's| *$$||' dfn2.out >dfn3.out
rm -f dfn.c dfn[12].out
mv dfn3.out $@
# The .dfn file for pnglibconf.h is machine generated
-pnglibconf.dfn: scripts/pnglibconf.dfa scripts/options.awk
+pnglibconf.dfn: scripts/pnglibconf.dfa scripts/options.awk pngconf.h
rm -f $@ dfn?.out
- $(AWK) -f ${srcdir}/scripts/options.awk out=dfn1.out\
- ${srcdir}/scripts/pnglibconf.dfa $(DFA_XTRA) 1>&2
+ $(AWK) -f ${srcdir}/scripts/options.awk out=dfn1.out version=search\
+ ${srcdir}/pngconf.h ${srcdir}/scripts/pnglibconf.dfa\
+ $(DFA_XTRA) 1>&2
$(AWK) -f ${srcdir}/scripts/options.awk out=dfn2.out dfn1.out 1>&2
rm dfn1.out
mv dfn2.out $@
@@ -162,14 +171,15 @@
mv symbols.new $@
# used on demand to regenerate the standard header, CPPFLAGS should
# be empty - no non-standard defines
-scripts/pnglibconf.dfn: scripts/pnglibconf.dfa scripts/options.awk
+scripts/pnglibconf.dfn: scripts/pnglibconf.dfa scripts/options.awk pngconf.h
rm -f $@ dfn?.out
test -z "$(CPPFLAGS)"
echo "com @PNGLIB_VERSION@ STANDARD API DEFINITION" |\
- $(AWK) -f ${srcdir}/scripts/options.awk out=dfn1.out\
- logunsupported=1 - ${srcdir}/scripts/pnglibconf.dfa 1>&2
+ $(AWK) -f ${srcdir}/scripts/options.awk out=dfn1.out logunsupported=1
+ version=search ${srcdir}/pngconf.h -\
+ ${srcdir}/scripts/pnglibconf.dfa 1>&2
$(AWK) -f ${srcdir}/scripts/options.awk out=dfn2.out dfn1.out 1>&2
rm dfn1.out
mv dfn2.out $@
diff -ru4NwbB libpng-1.5.6/arm/filter_neon.S libpng-1.5.7/arm/filter_neon.S
--- libpng-1.5.6/arm/filter_neon.S 1969-12-31 18:00:00.000000000 -0600
+++ libpng-1.5.7/arm/filter_neon.S 2011-11-16 23:02:48.612067000 -0600
@@ -0,0 +1,225 @@
+
+/* filter_neon.S - NEON optimised filter functions
+ *
+ * Copyright (c) 2011 Glenn Randers-Pehrson
+ * Written by Mans Rullgard, 2011.
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ */
+
+#if defined(__linux__) && defined(__ELF__)
+.section .note.GNU-stack,"",%progbits /* mark stack as non-executable */
+#endif
+
+#ifdef __ELF__
+# define ELF
+#else
+# define ELF @
+#endif
+
+ .arch armv7-a
+ .fpu neon
+
+.macro func name, export=0
+ .macro endfunc
+ELF .size \name, . - \name
+ .endfunc
+ .purgem endfunc
+ .endm
+ .text
+ .if \export
+ .global \name
+ .endif
+ELF .type \name, STT_FUNC
+ .func \name
+\name:
+.endm
+
+func png_read_filter_row_sub4_neon, export=1
+ ldr r3, [r0, #4] @ rowbytes
+ vmov.i8 d3, #0
+1:
+ vld4.32 {d4[],d5[],d6[],d7[]}, [r1,:128]
+ vadd.u8 d0, d3, d4
+ vadd.u8 d1, d0, d5
+ vadd.u8 d2, d1, d6
+ vadd.u8 d3, d2, d7
+ vst4.32 {d0[0],d1[0],d2[0],d3[0]},[r1,:128]!
+ subs r3, r3, #16
+ bgt 1b
+
+ bx lr
+endfunc
+
+func png_read_filter_row_sub3_neon, export=1
+ ldr r3, [r0, #4] @ rowbytes
+ vmov.i8 d3, #0
+ mov r0, r1
+ mov r2, #3
+ mov r12, #12
+ vld1.8 {q11}, [r0], r12
+1:
+ vext.8 d5, d22, d23, #3
+ vadd.u8 d0, d3, d22
+ vext.8 d6, d22, d23, #6
+ vadd.u8 d1, d0, d5
+ vext.8 d7, d23, d23, #1
+ vld1.8 {q11}, [r0], r12
+ vst1.32 {d0[0]}, [r1,:32], r2
+ vadd.u8 d2, d1, d6
+ vst1.32 {d1[0]}, [r1], r2
+ vadd.u8 d3, d2, d7
+ vst1.32 {d2[0]}, [r1], r2
+ vst1.32 {d3[0]}, [r1], r2
+ subs r3, r3, #12
+ bgt 1b
+
+ bx lr
+endfunc
+
+func png_read_filter_row_up_neon, export=1
+ ldr r3, [r0, #4] @ rowbytes
+1:
+ vld1.8 {q0}, [r1,:128]
+ vld1.8 {q1}, [r2,:128]!
+ vadd.u8 q0, q0, q1
+ vst1.8 {q0}, [r1,:128]!
+ subs r3, r3, #16
+ bgt 1b
+
+ bx lr
+endfunc
+
+func png_read_filter_row_avg4_neon, export=1
+ ldr r12, [r0, #4] @ rowbytes
+ vmov.i8 d3, #0
+1:
+ vld4.32 {d4[],d5[],d6[],d7[]}, [r1,:128]
+ vld4.32 {d16[],d17[],d18[],d19[]},[r2,:128]!
+ vhadd.u8 d0, d3, d16
+ vadd.u8 d0, d0, d4
+ vhadd.u8 d1, d0, d17
+ vadd.u8 d1, d1, d5
+ vhadd.u8 d2, d1, d18
+ vadd.u8 d2, d2, d6
+ vhadd.u8 d3, d2, d19
+ vadd.u8 d3, d3, d7
+ vst4.32 {d0[0],d1[0],d2[0],d3[0]},[r1,:128]!
+ subs r12, r12, #16
+ bgt 1b
+
+ bx lr
+endfunc
+
+func png_read_filter_row_avg3_neon, export=1
+ push {r4,lr}
+ ldr r12, [r0, #4] @ rowbytes
+ vmov.i8 d3, #0
+ mov r0, r1
+ mov r4, #3
+ mov lr, #12
+ vld1.8 {q11}, [r0], lr
+1:
+ vld1.8 {q10}, [r2], lr
+ vext.8 d5, d22, d23, #3
+ vhadd.u8 d0, d3, d20
+ vext.8 d17, d20, d21, #3
+ vadd.u8 d0, d0, d22
+ vext.8 d6, d22, d23, #6
+ vhadd.u8 d1, d0, d17
+ vext.8 d18, d20, d21, #6
+ vadd.u8 d1, d1, d5
+ vext.8 d7, d23, d23, #1
+ vld1.8 {q11}, [r0], lr
+ vst1.32 {d0[0]}, [r1,:32], r4
+ vhadd.u8 d2, d1, d18
+ vst1.32 {d1[0]}, [r1], r4
+ vext.8 d19, d21, d21, #1
+ vadd.u8 d2, d2, d6
+ vhadd.u8 d3, d2, d19
+ vst1.32 {d2[0]}, [r1], r4
+ vadd.u8 d3, d3, d7
+ vst1.32 {d3[0]}, [r1], r4
+ subs r12, r12, #12
+ bgt 1b
+
+ pop {r4,pc}
+endfunc
+
+.macro paeth rx, ra, rb, rc
+ vaddl.u8 q12, \ra, \rb @ a + b
+ vaddl.u8 q15, \rc, \rc @ 2*c
+ vabdl.u8 q13, \rb, \rc @ pa
+ vabdl.u8 q14, \ra, \rc @ pb
+ vabd.u16 q15, q12, q15 @ pc
+ vcle.u16 q12, q13, q14 @ pa <= pb
+ vcle.u16 q13, q13, q15 @ pa <= pc
+ vcle.u16 q14, q14, q15 @ pb <= pc
+ vand q12, q12, q13 @ pa <= pb && pa <= pc
+ vmovn.u16 d28, q14
+ vmovn.u16 \rx, q12
+ vbsl d28, \rb, \rc
+ vbsl \rx, \ra, d28
+.endm
+
+func png_read_filter_row_paeth4_neon, export=1
+ ldr r12, [r0, #4] @ rowbytes
+ vmov.i8 d3, #0
+ vmov.i8 d20, #0
+1:
+ vld4.32 {d4[],d5[],d6[],d7[]}, [r1,:128]
+ vld4.32 {d16[],d17[],d18[],d19[]},[r2,:128]!
+ paeth d0, d3, d16, d20
+ vadd.u8 d0, d0, d4
+ paeth d1, d0, d17, d16
+ vadd.u8 d1, d1, d5
+ paeth d2, d1, d18, d17
+ vadd.u8 d2, d2, d6
+ paeth d3, d2, d19, d18
+ vmov d20, d19
+ vadd.u8 d3, d3, d7
+ vst4.32 {d0[0],d1[0],d2[0],d3[0]},[r1,:128]!
+ subs r12, r12, #16
+ bgt 1b
+
+ bx lr
+endfunc
+
+func png_read_filter_row_paeth3_neon, export=1
+ push {r4,lr}
+ ldr r12, [r0, #4] @ rowbytes
+ vmov.i8 d3, #0
+ vmov.i8 d4, #0
+ mov r0, r1
+ mov r4, #3
+ mov lr, #12
+ vld1.8 {q11}, [r0], lr
+1:
+ vld1.8 {q10}, [r2], lr
+ paeth d0, d3, d20, d4
+ vext.8 d5, d22, d23, #3
+ vadd.u8 d0, d0, d22
+ vext.8 d17, d20, d21, #3
+ paeth d1, d0, d17, d20
+ vst1.32 {d0[0]}, [r1,:32], r4
+ vext.8 d6, d22, d23, #6
+ vadd.u8 d1, d1, d5
+ vext.8 d18, d20, d21, #6
+ paeth d2, d1, d18, d17
+ vext.8 d7, d23, d23, #1
+ vld1.8 {q11}, [r0], lr
+ vst1.32 {d1[0]}, [r1], r4
+ vadd.u8 d2, d2, d6
+ vext.8 d19, d21, d21, #1
+ paeth d3, d2, d19, d18
+ vst1.32 {d2[0]}, [r1], r4
+ vmov d4, d19
+ vadd.u8 d3, d3, d7
+ vst1.32 {d3[0]}, [r1], r4
+ subs r12, r12, #12
+ bgt 1b
+
+ pop {r4,pc}
+endfunc
diff -ru4NwbB libpng-1.5.6/configure.ac libpng-1.5.7/configure.ac
--- libpng-1.5.6/configure.ac 2011-11-02 22:42:58.029005391 -0500
+++ libpng-1.5.7/configure.ac 2011-12-15 09:45:40.098268056 -0600
@@ -35,8 +35,9 @@
# Checks for programs.
AC_LANG([C])
AC_PROG_CC
+AM_PROG_AS
AC_PROG_LD
AC_PROG_CPP
AC_CHECK_TOOL(SED, sed, :)
AC_CHECK_TOOL(AWK, awk, :)
@@ -74,8 +75,9 @@
# Checks for typedefs, structures, and compiler characteristics.
AC_C_CONST
AC_TYPE_SIZE_T
AC_STRUCT_TM
+AC_C_RESTRICT
# Checks for library functions.
AC_FUNC_STRTOD
AC_CHECK_FUNCS([memset], , AC_ERROR([memset not found in libc]))
@@ -88,8 +90,13 @@
AC_CHECK_LIB(z, zlibVersion, ,
AC_CHECK_LIB(z, ${ZPREFIX}zlibVersion, ,
AC_ERROR([zlib not installed])))
+# The following is for pngvalid, to ensure it catches FP errors even on
+# platforms that don't enable FP exceptions, the function appears in the math
+# library (typically), it's not an error if it is not found.
+AC_CHECK_LIB([m], [feenableexcept])
+AC_CHECK_FUNCS([feenableexcept])
LIBPNG_DEFINES=-DPNG_CONFIGURE_LIBPNG
LIBPNG_DEFINES=$LIBPNG_DEFINES
AC_SUBST(LIBPNG_DEFINES)
@@ -176,8 +183,21 @@
fi],
[binconfigs='${binconfigs}'])
AC_SUBST([binconfigs])
+# Because GCC by default assembles code with an executable stack, even though it
+# compiles C code with a non-executable stack, it is necessary to do a fixup
+# here (this may by GCC specific)
+AC_SUBST([AM_CCASFLAGS], [-Wa,--noexecstack])
+
+AC_ARG_ENABLE([arm-neon],
+ AC_HELP_STRING([--enable-arm-neon], [Enable ARM NEON optimizations]),
+ [if test "${enableval}" = yes; then
+ AC_DEFINE([PNG_ARM_NEON], [1], [Enable ARM NEON optimizations])
+ AC_DEFINE([PNG_ALIGNED_MEMORY_SUPPORTED], [1], [Align row buffers])
+ fi])
+AM_CONDITIONAL([PNG_ARM_NEON], [test "${enable_arm_neon:-no}" = yes])
+
# Config files, substituting as above
AC_CONFIG_FILES([Makefile libpng.pc:libpng.pc.in])
AC_CONFIG_FILES([libpng-config:libpng-config.in],
[chmod +x libpng-config])
diff -ru4NwbB libpng-1.5.6/contrib/README.txt libpng-1.5.7/contrib/README.txt
--- libpng-1.5.6/contrib/README.txt 1969-12-31 18:00:00.000000000 -0600
+++ libpng-1.5.7/contrib/README.txt 2011-12-15 09:45:35.033352242 -0600
@@ -0,0 +1,4 @@
+
+This "contrib" directory contains contributions which are not necessarily under
+the libpng license, although all are open source. They are not part of
+libpng proper and are not used for building the library.
diff -ru4NwbB libpng-1.5.6/contrib/libtests/pngvalid.c libpng-1.5.7/contrib/libtests/pngvalid.c
--- libpng-1.5.6/contrib/libtests/pngvalid.c 1969-12-31 18:00:00.000000000 -0600
+++ libpng-1.5.7/contrib/libtests/pngvalid.c 2011-12-15 09:43:49.577464000 -0600
@@ -0,0 +1,9834 @@
+
+/* pngvalid.c - validate libpng by constructing then reading png files.
+ *
+ * Last changed in libpng 1.5.7 [December 15, 2011]
+ * Copyright (c) 2011 Glenn Randers-Pehrson
+ * Written by John Cunningham Bowler
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+ *
+ * NOTES:
+ * This is a C program that is intended to be linked against libpng. It
+ * generates bitmaps internally, stores them as PNG files (using the
+ * sequential write code) then reads them back (using the sequential
+ * read code) and validates that the result has the correct data.
+ *
+ * The program can be modified and extended to test the correctness of
+ * transformations performed by libpng.
+ */
+
+#define _POSIX_SOURCE 1
+#define _ISOC99_SOURCE 1 /* For floating point */
+#define _GNU_SOURCE 1 /* For the floating point exception extension */
+
+#include <signal.h>
+
+#ifdef HAVE_CONFIG_H
+# include "../../config.h"
+#endif
+
+#ifdef HAVE_FEENABLEEXCEPT
+# include <fenv.h>
+#endif
+
+#include "../../png.h"
+
+#if PNG_LIBPNG_VER < 10500
+/* This deliberately lacks the PNG_CONST. */
+typedef png_byte *png_const_bytep;
+
+/* This is copied from 1.5.1 png.h: */
+#define PNG_INTERLACE_ADAM7_PASSES 7
+#define PNG_PASS_START_ROW(pass) (((1U&~(pass))<<(3-((pass)>>1)))&7)
+#define PNG_PASS_START_COL(pass) (((1U& (pass))<<(3-(((pass)+1)>>1)))&7)
+#define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3)
+#define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)
+#define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\
+ -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass))
+#define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\
+ -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass))
+#define PNG_ROW_FROM_PASS_ROW(yIn, pass) \
+ (((yIn)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass))
+#define PNG_COL_FROM_PASS_COL(xIn, pass) \
+ (((xIn)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass))
+#define PNG_PASS_MASK(pass,off) ( \
+ ((0x110145AFU>>(((7-(off))-(pass))<<2)) & 0xFU) | \
+ ((0x01145AF0U>>(((7-(off))-(pass))<<2)) & 0xF0U))
+#define PNG_ROW_IN_INTERLACE_PASS(y, pass) \
+ ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1)
+#define PNG_COL_IN_INTERLACE_PASS(x, pass) \
+ ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1)
+
+/* These are needed too for the default build: */
+#define PNG_WRITE_16BIT_SUPPORTED
+#define PNG_READ_16BIT_SUPPORTED
+
+/* This comes from pnglibconf.h afer 1.5: */
+#define PNG_FP_1 100000
+#define PNG_GAMMA_THRESHOLD_FIXED\
+ ((png_fixed_point)(PNG_GAMMA_THRESHOLD * PNG_FP_1))
+#endif
+
+#include "zlib.h" /* For crc32 */
+
+#include <float.h> /* For floating point constants */
+#include <stdlib.h> /* For malloc */
+#include <string.h> /* For memcpy, memset */
+#include <math.h> /* For floor */
+
+/* Unused formal parameter errors are removed using the following macro which is
+ * expected to have no bad effects on performance.
+ */
+#ifndef UNUSED
+# if defined(__GNUC__) || defined(_MSC_VER)
+# define UNUSED(param) (void)param;
+# else
+# define UNUSED(param)
+# endif
+#endif
+
+/***************************** EXCEPTION HANDLING *****************************/
+#include "../visupng/cexcept.h"
+
+#ifdef __cplusplus
+# define this not_the_cpp_this
+# define new not_the_cpp_new
+# define voidcast(type, value) static_cast<type>(value)
+#else
+# define voidcast(type, value) (value)
+#endif /* __cplusplus */
+
+struct png_store;
+define_exception_type(struct png_store*);
+
+/* The following are macros to reduce typing everywhere where the well known
+ * name 'the_exception_context' must be defined.
+ */
+#define anon_context(ps) struct exception_context *the_exception_context = \
+ &(ps)->exception_context
+#define context(ps,fault) anon_context(ps); png_store *fault
+
+/******************************* UTILITIES ************************************/
+/* Error handling is particularly problematic in production code - error
+ * handlers often themselves have bugs which lead to programs that detect
+ * minor errors crashing. The following functions deal with one very
+ * common class of errors in error handlers - attempting to format error or
+ * warning messages into buffers that are too small.
+ */
+static size_t safecat(char *buffer, size_t bufsize, size_t pos,
+ PNG_CONST char *cat)
+{
+ while (pos < bufsize && cat != NULL && *cat != 0)
+ buffer[pos++] = *cat++;
+
+ if (pos >= bufsize)
+ pos = bufsize-1;
+
+ buffer[pos] = 0;
+ return pos;
+}
+
+static size_t safecatn(char *buffer, size_t bufsize, size_t pos, int n)
+{
+ char number[64];
+ sprintf(number, "%d", n);
+ return safecat(buffer, bufsize, pos, number);
+}
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+static size_t safecatd(char *buffer, size_t bufsize, size_t pos, double d,
+ int precision)
+{
+ char number[64];
+ sprintf(number, "%.*f", precision, d);
+ return safecat(buffer, bufsize, pos, number);
+}
+#endif
+
+static PNG_CONST char invalid[] = "invalid";
+static PNG_CONST char sep[] = ": ";
+
+static PNG_CONST char *colour_types[8] =
+{
+ "grayscale", invalid, "truecolour", "indexed-colour",
+ "grayscale with alpha", invalid, "truecolour with alpha", invalid
+};
+
+/* Convert a double precision value to fixed point. */
+static png_fixed_point
+fix(double d)
+{
+ d = floor(d * PNG_FP_1 + .5);
+ return (png_fixed_point)d;
+}
+
+/* Generate random bytes. This uses a boring repeatable algorithm and it
+ * is implemented here so that it gives the same set of numbers on every
+ * architecture. It's a linear congruential generator (Knuth or Sedgewick
+ * "Algorithms") but it comes from the 'feedback taps' table in Horowitz and
+ * Hill, "The Art of Electronics".
+ */
+static void
+make_random_bytes(png_uint_32* seed, void* pv, size_t size)
+{
+ png_uint_32 u0 = seed[0], u1 = seed[1];
+ png_bytep bytes = voidcast(png_bytep, pv);
+
+ /* There are thirty three bits, the next bit in the sequence is bit-33 XOR
+ * bit-20. The top 1 bit is in u1, the bottom 32 are in u0.
+ */
+ size_t i;
+ for (i=0; i<size; ++i)
+ {
+ /* First generate 8 new bits then shift them in at the end. */
+ png_uint_32 u = ((u0 >> (20-8)) ^ ((u1 << 7) | (u0 >> (32-7)))) & 0xff;
+ u1 <<= 8;
+ u1 |= u0 >> 24;
+ u0 <<= 8;
+ u0 |= u;
+ *bytes++ = (png_byte)u;
+ }
+
+ seed[0] = u0;
+ seed[1] = u1;
+}
+
+static void
+make_four_random_bytes(png_uint_32* seed, png_bytep bytes)
+{
+ make_random_bytes(seed, bytes, 4);
+}
+
+static void
+randomize(void *pv, size_t size)
+{
+ static png_uint_32 random_seed[2] = {0x56789abc, 0xd};
+ make_random_bytes(random_seed, pv, size);
+}
+
+#define RANDOMIZE(this) randomize(&(this), sizeof (this))
+
+static unsigned int
+random_mod(unsigned int max)
+{
+ unsigned int x;
+
+ RANDOMIZE(x);
+
+ return x % max; /* 0 .. max-1 */
+}
+
+static int
+random_choice(void)
+{
+ unsigned char x;
+
+ RANDOMIZE(x);
+
+ return x & 1;
+}
+
+/* A numeric ID based on PNG file characteristics. The 'do_interlace' field
+ * simply records whether pngvalid did the interlace itself or whether it
+ * was done by libpng. Width and height must be less than 256. 'palette' is an
+ * index of the palette to use for formats with a palette (0 otherwise.)
+ */
+#define FILEID(col, depth, palette, interlace, width, height, do_interlace) \
+ ((png_uint_32)((col) + ((depth)<<3) + ((palette)<<8) + ((interlace)<<13) + \
+ (((do_interlace)!=0)<<15) + ((width)<<16) + ((height)<<24)))
+
+#define COL_FROM_ID(id) ((png_byte)((id)& 0x7U))
+#define DEPTH_FROM_ID(id) ((png_byte)(((id) >> 3) & 0x1fU))
+#define PALETTE_FROM_ID(id) ((int)(((id) >> 8) & 0x1f))
+#define INTERLACE_FROM_ID(id) ((int)(((id) >> 13) & 0x3))
+#define DO_INTERLACE_FROM_ID(id) ((int)(((id)>>15) & 1))
+#define WIDTH_FROM_ID(id) (((id)>>16) & 0xff)
+#define HEIGHT_FROM_ID(id) (((id)>>24) & 0xff)
+
+/* Utility to construct a standard name for a standard image. */
+static size_t
+standard_name(char *buffer, size_t bufsize, size_t pos, png_byte colour_type,
+ int bit_depth, int npalette, int interlace_type,
+ png_uint_32 w, png_uint_32 h, int do_interlace)
+{
+ pos = safecat(buffer, bufsize, pos, colour_types[colour_type]);
+ if (npalette > 0)
+ {
+ pos = safecat(buffer, bufsize, pos, "[");
+ pos = safecatn(buffer, bufsize, pos, npalette);
+ pos = safecat(buffer, bufsize, pos, "]");
+ }
+ pos = safecat(buffer, bufsize, pos, " ");
+ pos = safecatn(buffer, bufsize, pos, bit_depth);
+ pos = safecat(buffer, bufsize, pos, " bit");
+
+ if (interlace_type != PNG_INTERLACE_NONE)
+ {
+ pos = safecat(buffer, bufsize, pos, " interlaced");
+ if (do_interlace)
+ pos = safecat(buffer, bufsize, pos, "(pngvalid)");
+ else
+ pos = safecat(buffer, bufsize, pos, "(libpng)");
+ }
+
+ if (w > 0 || h > 0)
+ {
+ pos = safecat(buffer, bufsize, pos, " ");
+ pos = safecatn(buffer, bufsize, pos, w);
+ pos = safecat(buffer, bufsize, pos, "x");
+ pos = safecatn(buffer, bufsize, pos, h);
+ }
+
+ return pos;
+}
+
+static size_t
+standard_name_from_id(char *buffer, size_t bufsize, size_t pos, png_uint_32 id)
+{
+ return standard_name(buffer, bufsize, pos, COL_FROM_ID(id),
+ DEPTH_FROM_ID(id), PALETTE_FROM_ID(id), INTERLACE_FROM_ID(id),
+ WIDTH_FROM_ID(id), HEIGHT_FROM_ID(id), DO_INTERLACE_FROM_ID(id));
+}
+
+/* Convenience API and defines to list valid formats. Note that 16 bit read and
+ * write support is required to do 16 bit read tests (we must be able to make a
+ * 16 bit image to test!)
+ */
+#ifdef PNG_WRITE_16BIT_SUPPORTED
+# define WRITE_BDHI 4
+# ifdef PNG_READ_16BIT_SUPPORTED
+# define READ_BDHI 4
+# define DO_16BIT
+# endif
+#else
+# define WRITE_BDHI 3
+#endif
+#ifndef DO_16BIT
+# define READ_BDHI 3
+#endif
+
+/* The following defines the number of different palettes to generate for
+ * each log bit depth of a colour type 3 standard image.
+ */
+#define PALETTE_COUNT(bit_depth) ((bit_depth) > 4 ? 1 : 16)
+
+static int
+next_format(png_bytep colour_type, png_bytep bit_depth, int* palette_number)
+{
+ if (*bit_depth == 0)
+ {
+ *colour_type = 0, *bit_depth = 1, *palette_number = 0;
+ return 1;
+ }
+
+ if (*colour_type == 3)
+ {
+ /* Add multiple palettes for colour type 3. */
+ if (++*palette_number < PALETTE_COUNT(*bit_depth))
+ return 1;
+
+ *palette_number = 0;
+ }
+
+ *bit_depth = (png_byte)(*bit_depth << 1);
+
+ /* Palette images are restricted to 8 bit depth */
+ if (*bit_depth <= 8
+# ifdef DO_16BIT
+ || (*colour_type != 3 && *bit_depth <= 16)
+# endif
+ )
+ return 1;
+
+ /* Move to the next color type, or return 0 at the end. */
+ switch (*colour_type)
+ {
+ case 0:
+ *colour_type = 2;
+ *bit_depth = 8;
+ return 1;
+
+ case 2:
+ *colour_type = 3;
+ *bit_depth = 1;
+ return 1;
+
+ case 3:
+ *colour_type = 4;
+ *bit_depth = 8;
+ return 1;
+
+ case 4:
+ *colour_type = 6;
+ *bit_depth = 8;
+ return 1;
+
+ default:
+ return 0;
+ }
+}
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+static unsigned int
+sample(png_const_bytep row, png_byte colour_type, png_byte bit_depth,
+ png_uint_32 x, unsigned int sample_index)
+{
+ png_uint_32 bit_index, result;
+
+ /* Find a sample index for the desired sample: */
+ x *= bit_depth;
+ bit_index = x;
+
+ if ((colour_type & 1) == 0) /* !palette */
+ {
+ if (colour_type & 2)
+ bit_index *= 3;
+
+ if (colour_type & 4)
+ bit_index += x; /* Alpha channel */
+
+ /* Multiple channels; select one: */
+ if (colour_type & (2+4))
+ bit_index += sample_index * bit_depth;
+ }
+
+ /* Return the sample from the row as an integer. */
+ row += bit_index >> 3;
+ result = *row;
+
+ if (bit_depth == 8)
+ return result;
+
+ else if (bit_depth > 8)
+ return (result << 8) + *++row;
+
+ /* Less than 8 bits per sample. */
+ bit_index &= 7;
+ return (result >> (8-bit_index-bit_depth)) & ((1U<<bit_depth)-1);
+}
+#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
+
+/* Copy a single pixel, of a given size, from one buffer to another -
+ * while this is basically bit addressed there is an implicit assumption
+ * that pixels 8 or more bits in size are byte aligned and that pixels
+ * do not otherwise cross byte boundaries. (This is, so far as I know,
+ * universally true in bitmap computer graphics. [JCB 20101212])
+ *
+ * NOTE: The to and from buffers may be the same.
+ */
+static void
+pixel_copy(png_bytep toBuffer, png_uint_32 toIndex,
+ png_const_bytep fromBuffer, png_uint_32 fromIndex, unsigned int pixelSize)
+{
+ /* Assume we can multiply by 'size' without overflow because we are
+ * just working in a single buffer.
+ */
+ toIndex *= pixelSize;
+ fromIndex *= pixelSize;
+ if (pixelSize < 8) /* Sub-byte */
+ {
+ /* Mask to select the location of the copied pixel: */
+ unsigned int destMask = ((1U<<pixelSize)-1) << (8-pixelSize-(toIndex&7));
+ /* The following read the entire pixels and clears the extra: */
+ unsigned int destByte = toBuffer[toIndex >> 3] & ~destMask;
+ unsigned int sourceByte = fromBuffer[fromIndex >> 3];
+
+ /* Don't rely on << or >> supporting '0' here, just in case: */
+ fromIndex &= 7;
+ if (fromIndex > 0) sourceByte <<= fromIndex;
+ if ((toIndex & 7) > 0) sourceByte >>= toIndex & 7;
+
+ toBuffer[toIndex >> 3] = (png_byte)(destByte | (sourceByte & destMask));
+ }
+ else /* One or more bytes */
+ memmove(toBuffer+(toIndex>>3), fromBuffer+(fromIndex>>3), pixelSize>>3);
+}
+
+/* Copy a complete row of pixels, taking into account potential partial
+ * bytes at the end.
+ */
+static void
+row_copy(png_bytep toBuffer, png_const_bytep fromBuffer, unsigned int bitWidth)
+{
+ memcpy(toBuffer, fromBuffer, bitWidth >> 3);
+
+ if ((bitWidth & 7) != 0)
+ {
+ unsigned int mask;
+
+ toBuffer += bitWidth >> 3;
+ fromBuffer += bitWidth >> 3;
+ /* The remaining bits are in the top of the byte, the mask is the bits to
+ * retain.
+ */
+ mask = 0xff >> (bitWidth & 7);
+ *toBuffer = (png_byte)((*toBuffer & mask) | (*fromBuffer & ~mask));
+ }
+}
+
+/* Compare pixels - they are assumed to start at the first byte in the
+ * given buffers.
+ */
+static int
+pixel_cmp(png_const_bytep pa, png_const_bytep pb, png_uint_32 bit_width)
+{
+#if PNG_LIBPNG_VER < 10506
+ if (memcmp(pa, pb, bit_width>>3) == 0)
+ {
+ png_uint_32 p;
+
+ if ((bit_width & 7) == 0) return 0;
+
+ /* Ok, any differences? */
+ p = pa[bit_width >> 3];
+ p ^= pb[bit_width >> 3];
+
+ if (p == 0) return 0;
+
+ /* There are, but they may not be significant, remove the bits
+ * after the end (the low order bits in PNG.)
+ */
+ bit_width &= 7;
+ p >>= 8-bit_width;
+
+ if (p == 0) return 0;
+ }
+#else
+ /* From libpng-1.5.6 the overwrite should be fixed, so compare the trailing
+ * bits too:
+ */
+ if (memcmp(pa, pb, (bit_width+7)>>3) == 0)
+ return 0;
+#endif
+
+ /* Return the index of the changed byte. */
+ {
+ png_uint_32 where = 0;
+
+ while (pa[where] == pb[where]) ++where;
+ return 1+where;
+ }
+}
+
+/*************************** BASIC PNG FILE WRITING ***************************/
+/* A png_store takes data from the sequential writer or provides data
+ * to the sequential reader. It can also store the result of a PNG
+ * write for later retrieval.
+ */
+#define STORE_BUFFER_SIZE 500 /* arbitrary */
+typedef struct png_store_buffer
+{
+ struct png_store_buffer* prev; /* NOTE: stored in reverse order */
+ png_byte buffer[STORE_BUFFER_SIZE];
+} png_store_buffer;
+
+#define FILE_NAME_SIZE 64
+
+typedef struct store_palette_entry /* record of a single palette entry */
+{
+ png_byte red;
+ png_byte green;
+ png_byte blue;
+ png_byte alpha;
+} store_palette_entry, store_palette[256];
+
+typedef struct png_store_file
+{
+ struct png_store_file* next; /* as many as you like... */
+ char name[FILE_NAME_SIZE];
+ png_uint_32 id; /* must be correct (see FILEID) */
+ png_size_t datacount; /* In this (the last) buffer */
+ png_store_buffer data; /* Last buffer in file */
+ int npalette; /* Number of entries in palette */
+ store_palette_entry* palette; /* May be NULL */
+} png_store_file;
+
+/* The following is a pool of memory allocated by a single libpng read or write
+ * operation.
+ */
+typedef struct store_pool
+{
+ struct png_store *store; /* Back pointer */
+ struct store_memory *list; /* List of allocated memory */
+ png_byte mark[4]; /* Before and after data */
+
+ /* Statistics for this run. */
+ png_alloc_size_t max; /* Maximum single allocation */
+ png_alloc_size_t current; /* Current allocation */
+ png_alloc_size_t limit; /* Highest current allocation */
+ png_alloc_size_t total; /* Total allocation */
+
+ /* Overall statistics (retained across successive runs). */
+ png_alloc_size_t max_max;
+ png_alloc_size_t max_limit;
+ png_alloc_size_t max_total;
+} store_pool;
+
+typedef struct png_store
+{
+ /* For cexcept.h exception handling - simply store one of these;
+ * the context is a self pointer but it may point to a different
+ * png_store (in fact it never does in this program.)
+ */
+ struct exception_context
+ exception_context;
+
+ unsigned int verbose :1;
+ unsigned int treat_warnings_as_errors :1;
+ unsigned int expect_error :1;
+ unsigned int expect_warning :1;
+ unsigned int saw_warning :1;
+ unsigned int speed :1;
+ unsigned int progressive :1; /* use progressive read */
+ unsigned int validated :1; /* used as a temporary flag */
+ int nerrors;
+ int nwarnings;
+ char test[128]; /* Name of test */
+ char error[256];
+
+ /* Read fields */
+ png_structp pread; /* Used to read a saved file */
+ png_infop piread;
+ png_store_file* current; /* Set when reading */
+ png_store_buffer* next; /* Set when reading */
+ png_size_t readpos; /* Position in *next */
+ png_byte* image; /* Buffer for reading interlaced images */
+ png_size_t cb_image; /* Size of this buffer */
+ png_size_t cb_row; /* Row size of the image(s) */
+ png_uint_32 image_h; /* Number of rows in a single image */
+ store_pool read_memory_pool;
+
+ /* Write fields */
+ png_store_file* saved;
+ png_structp pwrite; /* Used when writing a new file */
+ png_infop piwrite;
+ png_size_t writepos; /* Position in .new */
+ char wname[FILE_NAME_SIZE];
+ png_store_buffer new; /* The end of the new PNG file being written. */
+ store_pool write_memory_pool;
+ store_palette_entry* palette;
+ int npalette;
+} png_store;
+
+/* Initialization and cleanup */
+static void
+store_pool_mark(png_bytep mark)
+{
+ static png_uint_32 store_seed[2] = { 0x12345678, 1};
+
+ make_four_random_bytes(store_seed, mark);
+}
+
+/* Use this for random 32 bit values; this function makes sure the result is
+ * non-zero.
+ */
+static png_uint_32
+random_32(void)
+{
+
+ for(;;)
+ {
+ png_byte mark[4];
+ png_uint_32 result;
+
+ store_pool_mark(mark);
+ result = png_get_uint_32(mark);
+
+ if (result != 0)
+ return result;
+ }
+}
+
+static void
+store_pool_init(png_store *ps, store_pool *pool)
+{
+ memset(pool, 0, sizeof *pool);
+
+ pool->store = ps;
+ pool->list = NULL;
+ pool->max = pool->current = pool->limit = pool->total = 0;
+ pool->max_max = pool->max_limit = pool->max_total = 0;
+ store_pool_mark(pool->mark);
+}
+
+static void
+store_init(png_store* ps)
+{
+ memset(ps, 0, sizeof *ps);
+ init_exception_context(&ps->exception_context);
+ store_pool_init(ps, &ps->read_memory_pool);
+ store_pool_init(ps, &ps->write_memory_pool);
+ ps->verbose = 0;
+ ps->treat_warnings_as_errors = 0;
+ ps->expect_error = 0;
+ ps->expect_warning = 0;
+ ps->saw_warning = 0;
+ ps->speed = 0;
+ ps->progressive = 0;
+ ps->validated = 0;
+ ps->nerrors = ps->nwarnings = 0;
+ ps->pread = NULL;
+ ps->piread = NULL;
+ ps->saved = ps->current = NULL;
+ ps->next = NULL;
+ ps->readpos = 0;
+ ps->image = NULL;
+ ps->cb_image = 0;
+ ps->cb_row = 0;
+ ps->image_h = 0;
+ ps->pwrite = NULL;
+ ps->piwrite = NULL;
+ ps->writepos = 0;
+ ps->new.prev = NULL;
+ ps->palette = NULL;
+ ps->npalette = 0;
+}
+
+static void
+store_freebuffer(png_store_buffer* psb)
+{
+ if (psb->prev)
+ {
+ store_freebuffer(psb->prev);
+ free(psb->prev);
+ psb->prev = NULL;
+ }
+}
+
+static void
+store_freenew(png_store *ps)
+{
+ store_freebuffer(&ps->new);
+ ps->writepos = 0;
+ if (ps->palette != NULL)
+ {
+ free(ps->palette);
+ ps->palette = NULL;
+ ps->npalette = 0;
+ }
+}
+
+static void
+store_storenew(png_store *ps)
+{
+ png_store_buffer *pb;
+
+ if (ps->writepos != STORE_BUFFER_SIZE)
+ png_error(ps->pwrite, "invalid store call");
+
+ pb = voidcast(png_store_buffer*, malloc(sizeof *pb));
+
+ if (pb == NULL)
+ png_error(ps->pwrite, "store new: OOM");
+
+ *pb = ps->new;
+ ps->new.prev = pb;
+ ps->writepos = 0;
+}
+
+static void
+store_freefile(png_store_file **ppf)
+{
+ if (*ppf != NULL)
+ {
+ store_freefile(&(*ppf)->next);
+
+ store_freebuffer(&(*ppf)->data);
+ (*ppf)->datacount = 0;
+ if ((*ppf)->palette != NULL)
+ {
+ free((*ppf)->palette);
+ (*ppf)->palette = NULL;
+ (*ppf)->npalette = 0;
+ }
+ free(*ppf);
+ *ppf = NULL;
+ }
+}
+
+/* Main interface to file storeage, after writing a new PNG file (see the API
+ * below) call store_storefile to store the result with the given name and id.
+ */
+static void
+store_storefile(png_store *ps, png_uint_32 id)
+{
+ png_store_file *pf = voidcast(png_store_file*, malloc(sizeof *pf));
+ if (pf == NULL)
+ png_error(ps->pwrite, "storefile: OOM");
+ safecat(pf->name, sizeof pf->name, 0, ps->wname);
+ pf->id = id;
+ pf->data = ps->new;
+ pf->datacount = ps->writepos;
+ ps->new.prev = NULL;
+ ps->writepos = 0;
+ pf->palette = ps->palette;
+ pf->npalette = ps->npalette;
+ ps->palette = 0;
+ ps->npalette = 0;
+
+ /* And save it. */
+ pf->next = ps->saved;
+ ps->saved = pf;
+}
+
+/* Generate an error message (in the given buffer) */
+static size_t
+store_message(png_store *ps, png_structp pp, char *buffer, size_t bufsize,
+ size_t pos, PNG_CONST char *msg)
+{
+ if (pp != NULL && pp == ps->pread)
+ {
+ /* Reading a file */
+ pos = safecat(buffer, bufsize, pos, "read: ");
+
+ if (ps->current != NULL)
+ {
+ pos = safecat(buffer, bufsize, pos, ps->current->name);
+ pos = safecat(buffer, bufsize, pos, sep);
+ }
+ }
+
+ else if (pp != NULL && pp == ps->pwrite)
+ {
+ /* Writing a file */
+ pos = safecat(buffer, bufsize, pos, "write: ");
+ pos = safecat(buffer, bufsize, pos, ps->wname);
+ pos = safecat(buffer, bufsize, pos, sep);
+ }
+
+ else
+ {
+ /* Neither reading nor writing (or a memory error in struct delete) */
+ pos = safecat(buffer, bufsize, pos, "pngvalid: ");
+ }
+
+ if (ps->test[0] != 0)
+ {
+ pos = safecat(buffer, bufsize, pos, ps->test);
+ pos = safecat(buffer, bufsize, pos, sep);
+ }
+ pos = safecat(buffer, bufsize, pos, msg);
+ return pos;
+}
+
+/* Verbose output to the error stream: */
+static void
+store_verbose(png_store *ps, png_structp pp, png_const_charp prefix,
+ png_const_charp message)
+{
+ char buffer[512];
+
+ if (prefix)
+ fputs(prefix, stderr);
+
+ (void)store_message(ps, pp, buffer, sizeof buffer, 0, message);
+ fputs(buffer, stderr);
+ fputc('\n', stderr);
+}
+
+/* Log an error or warning - the relevant count is always incremented. */
+static void
+store_log(png_store* ps, png_structp pp, png_const_charp message, int is_error)
+{
+ /* The warning is copied to the error buffer if there are no errors and it is
+ * the first warning. The error is copied to the error buffer if it is the
+ * first error (overwriting any prior warnings).
+ */
+ if (is_error ? (ps->nerrors)++ == 0 :
+ (ps->nwarnings)++ == 0 && ps->nerrors == 0)
+ store_message(ps, pp, ps->error, sizeof ps->error, 0, message);
+
+ if (ps->verbose)
+ store_verbose(ps, pp, is_error ? "error: " : "warning: ", message);
+}
+
+/* Internal error function, called with a png_store but no libpng stuff. */
+static void
+internal_error(png_store *ps, png_const_charp message)
+{
+ store_log(ps, NULL, message, 1 /* error */);
+
+ /* And finally throw an exception. */
+ {
+ struct exception_context *the_exception_context = &ps->exception_context;
+ Throw ps;
+ }
+}
+
+/* Functions to use as PNG callbacks. */
+static void
+store_error(png_structp pp, png_const_charp message) /* PNG_NORETURN */
+{
+ png_store *ps = voidcast(png_store*, png_get_error_ptr(pp));
+
+ if (!ps->expect_error)
+ store_log(ps, pp, message, 1 /* error */);
+
+ /* And finally throw an exception. */
+ {
+ struct exception_context *the_exception_context = &ps->exception_context;
+ Throw ps;
+ }
+}
+
+static void
+store_warning(png_structp pp, png_const_charp message)
+{
+ png_store *ps = voidcast(png_store*, png_get_error_ptr(pp));
+
+ if (!ps->expect_warning)
+ store_log(ps, pp, message, 0 /* warning */);
+ else
+ ps->saw_warning = 1;
+}
+
+/* These somewhat odd functions are used when reading an image to ensure that
+ * the buffer is big enough, the png_structp is for errors.
+ */
+/* Return a single row from the correct image. */
+static png_bytep
+store_image_row(PNG_CONST png_store* ps, png_structp pp, int nImage,
+ png_uint_32 y)
+{
+ png_size_t coffset = (nImage * ps->image_h + y) * (ps->cb_row + 5) + 2;
+
+ if (ps->image == NULL)
+ png_error(pp, "no allocated image");
+
+ if (coffset + ps->cb_row + 3 > ps->cb_image)
+ png_error(pp, "image too small");
+
+ return ps->image + coffset;
+}
+
+static void
+store_image_free(png_store *ps, png_structp pp)
+{
+ if (ps->image != NULL)
+ {
+ png_bytep image = ps->image;
+
+ if (image[-1] != 0xed || image[ps->cb_image] != 0xfe)
+ {
+ if (pp != NULL)
+ png_error(pp, "png_store image overwrite (1)");
+ else
+ store_log(ps, NULL, "png_store image overwrite (2)", 1);
+ }
+
+ ps->image = NULL;
+ ps->cb_image = 0;
+ --image;
+ free(image);
+ }
+}
+
+static void
+store_ensure_image(png_store *ps, png_structp pp, int nImages, png_size_t cbRow,
+ png_uint_32 cRows)
+{
+ png_size_t cb = nImages * cRows * (cbRow + 5);
+
+ if (ps->cb_image < cb)
+ {
+ png_bytep image;
+
+ store_image_free(ps, pp);
+
+ /* The buffer is deliberately mis-aligned. */
+ image = voidcast(png_bytep, malloc(cb+2));
+ if (image == NULL)
+ {
+ /* Called from the startup - ignore the error for the moment. */
+ if (pp == NULL)
+ return;
+
+ png_error(pp, "OOM allocating image buffer");
+ }
+
+ /* These magic tags are used to detect overwrites above. */
+ ++image;
+ image[-1] = 0xed;
+ image[cb] = 0xfe;
+
+ ps->image = image;
+ ps->cb_image = cb;
+ }
+
+ /* We have an adequate sized image; lay out the rows. There are 2 bytes at
+ * the start and three at the end of each (this ensures that the row
+ * alignment starts out odd - 2+1 and changes for larger images on each row.)
+ */
+ ps->cb_row = cbRow;
+ ps->image_h = cRows;
+
+ /* For error checking, the whole buffer is set to 10110010 (0xb2 - 178).
+ * This deliberately doesn't match the bits in the size test image which are
+ * outside the image; these are set to 0xff (all 1). To make the row
+ * comparison work in the 'size' test case the size rows are pre-initialized
+ * to the same value prior to calling 'standard_row'.
+ */
+ memset(ps->image, 178, cb);
+
+ /* Then put in the marks. */
+ while (--nImages >= 0)
+ {
+ png_uint_32 y;
+
+ for (y=0; y<cRows; ++y)
+ {
+ png_bytep row = store_image_row(ps, pp, nImages, y);
+
+ /* The markers: */
+ row[-2] = 190;
+ row[-1] = 239;
+ row[cbRow] = 222;
+ row[cbRow+1] = 173;
+ row[cbRow+2] = 17;
+ }
+ }
+}
+
+static void
+store_image_check(PNG_CONST png_store* ps, png_structp pp, int iImage)
+{
+ png_const_bytep image = ps->image;
+
+ if (image[-1] != 0xed || image[ps->cb_image] != 0xfe)
+ png_error(pp, "image overwrite");
+ else
+ {
+ png_size_t cbRow = ps->cb_row;
+ png_uint_32 rows = ps->image_h;
+
+ image += iImage * (cbRow+5) * ps->image_h;
+
+ image += 2; /* skip image first row markers */
+
+ while (rows-- > 0)
+ {
+ if (image[-2] != 190 || image[-1] != 239)
+ png_error(pp, "row start overwritten");
+
+ if (image[cbRow] != 222 || image[cbRow+1] != 173 ||
+ image[cbRow+2] != 17)
+ png_error(pp, "row end overwritten");
+
+ image += cbRow+5;
+ }
+ }
+}
+
+static void
+store_write(png_structp pp, png_bytep pb, png_size_t st)
+{
+ png_store *ps = voidcast(png_store*, png_get_io_ptr(pp));
+
+ if (ps->pwrite != pp)
+ png_error(pp, "store state damaged");
+
+ while (st > 0)
+ {
+ size_t cb;
+
+ if (ps->writepos >= STORE_BUFFER_SIZE)
+ store_storenew(ps);
+
+ cb = st;
+
+ if (cb > STORE_BUFFER_SIZE - ps->writepos)
+ cb = STORE_BUFFER_SIZE - ps->writepos;
+
+ memcpy(ps->new.buffer + ps->writepos, pb, cb);
+ pb += cb;
+ st -= cb;
+ ps->writepos += cb;
+ }
+}
+
+static void
+store_flush(png_structp pp)
+{
+ UNUSED(pp) /*DOES NOTHING*/
+}
+
+static size_t
+store_read_buffer_size(png_store *ps)
+{
+ /* Return the bytes available for read in the current buffer. */
+ if (ps->next != &ps->current->data)
+ return STORE_BUFFER_SIZE;
+
+ return ps->current->datacount;
+}
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+/* Return total bytes available for read. */
+static size_t
+store_read_buffer_avail(png_store *ps)
+{
+ if (ps->current != NULL && ps->next != NULL)
+ {
+ png_store_buffer *next = &ps->current->data;
+ size_t cbAvail = ps->current->datacount;
+
+ while (next != ps->next && next != NULL)
+ {
+ next = next->prev;
+ cbAvail += STORE_BUFFER_SIZE;
+ }
+
+ if (next != ps->next)
+ png_error(ps->pread, "buffer read error");
+
+ if (cbAvail > ps->readpos)
+ return cbAvail - ps->readpos;
+ }
+
+ return 0;
+}
+#endif
+
+static int
+store_read_buffer_next(png_store *ps)
+{
+ png_store_buffer *pbOld = ps->next;
+ png_store_buffer *pbNew = &ps->current->data;
+ if (pbOld != pbNew)
+ {
+ while (pbNew != NULL && pbNew->prev != pbOld)
+ pbNew = pbNew->prev;
+
+ if (pbNew != NULL)
+ {
+ ps->next = pbNew;
+ ps->readpos = 0;
+ return 1;
+ }
+
+ png_error(ps->pread, "buffer lost");
+ }
+
+ return 0; /* EOF or error */
+}
+
+/* Need separate implementation and callback to allow use of the same code
+ * during progressive read, where the io_ptr is set internally by libpng.
+ */
+static void
+store_read_imp(png_store *ps, png_bytep pb, png_size_t st)
+{
+ if (ps->current == NULL || ps->next == NULL)
+ png_error(ps->pread, "store state damaged");
+
+ while (st > 0)
+ {
+ size_t cbAvail = store_read_buffer_size(ps) - ps->readpos;
+
+ if (cbAvail > 0)
+ {
+ if (cbAvail > st) cbAvail = st;
+ memcpy(pb, ps->next->buffer + ps->readpos, cbAvail);
+ st -= cbAvail;
+ pb += cbAvail;
+ ps->readpos += cbAvail;
+ }
+
+ else if (!store_read_buffer_next(ps))
+ png_error(ps->pread, "read beyond end of file");
+ }
+}
+
+static void
+store_read(png_structp pp, png_bytep pb, png_size_t st)
+{
+ png_store *ps = voidcast(png_store*, png_get_io_ptr(pp));
+
+ if (ps == NULL || ps->pread != pp)
+ png_error(pp, "bad store read call");
+
+ store_read_imp(ps, pb, st);
+}
+
+static void
+store_progressive_read(png_store *ps, png_structp pp, png_infop pi)
+{
+ /* Notice that a call to store_read will cause this function to fail because
+ * readpos will be set.
+ */
+ if (ps->pread != pp || ps->current == NULL || ps->next == NULL)
+ png_error(pp, "store state damaged (progressive)");
+
+ do
+ {
+ if (ps->readpos != 0)
+ png_error(pp, "store_read called during progressive read");
+
+ png_process_data(pp, pi, ps->next->buffer, store_read_buffer_size(ps));
+ }
+ while (store_read_buffer_next(ps));
+}
+
+/* The caller must fill this in: */
+static store_palette_entry *
+store_write_palette(png_store *ps, int npalette)
+{
+ if (ps->pwrite == NULL)
+ store_log(ps, NULL, "attempt to write palette without write stream", 1);
+
+ if (ps->palette != NULL)
+ png_error(ps->pwrite, "multiple store_write_palette calls");
+
+ /* This function can only return NULL if called with '0'! */
+ if (npalette > 0)
+ {
+ ps->palette = voidcast(store_palette_entry*, malloc(npalette *
+ sizeof *ps->palette));
+
+ if (ps->palette == NULL)
+ png_error(ps->pwrite, "store new palette: OOM");
+
+ ps->npalette = npalette;
+ }
+
+ return ps->palette;
+}
+
+static store_palette_entry *
+store_current_palette(png_store *ps, int *npalette)
+{
+ /* This is an internal error (the call has been made outside a read
+ * operation.)
+ */
+ if (ps->current == NULL)
+ store_log(ps, ps->pread, "no current stream for palette", 1);
+
+ /* The result may be null if there is no palette. */
+ *npalette = ps->current->npalette;
+ return ps->current->palette;
+}
+
+/***************************** MEMORY MANAGEMENT*** ***************************/
+/* A store_memory is simply the header for an allocated block of memory. The
+ * pointer returned to libpng is just after the end of the header block, the
+ * allocated memory is followed by a second copy of the 'mark'.
+ */
+typedef struct store_memory
+{
+ store_pool *pool; /* Originating pool */
+ struct store_memory *next; /* Singly linked list */
+ png_alloc_size_t size; /* Size of memory allocated */
+ png_byte mark[4]; /* ID marker */
+} store_memory;
+
+/* Handle a fatal error in memory allocation. This calls png_error if the
+ * libpng struct is non-NULL, else it outputs a message and returns. This means
+ * that a memory problem while libpng is running will abort (png_error) the
+ * handling of particular file while one in cleanup (after the destroy of the
+ * struct has returned) will simply keep going and free (or attempt to free)
+ * all the memory.
+ */
+static void
+store_pool_error(png_store *ps, png_structp pp, PNG_CONST char *msg)
+{
+ if (pp != NULL)
+ png_error(pp, msg);
+
+ /* Else we have to do it ourselves. png_error eventually calls store_log,
+ * above. store_log accepts a NULL png_structp - it just changes what gets
+ * output by store_message.
+ */
+ store_log(ps, pp, msg, 1 /* error */);
+}
+
+static void
+store_memory_free(png_structp pp, store_pool *pool, store_memory *memory)
+{
+ /* Note that pp may be NULL (see store_pool_delete below), the caller has
+ * found 'memory' in pool->list *and* unlinked this entry, so this is a valid
+ * pointer (for sure), but the contents may have been trashed.
+ */
+ if (memory->pool != pool)
+ store_pool_error(pool->store, pp, "memory corrupted (pool)");
+
+ else if (memcmp(memory->mark, pool->mark, sizeof memory->mark) != 0)
+ store_pool_error(pool->store, pp, "memory corrupted (start)");
+
+ /* It should be safe to read the size field now. */
+ else
+ {
+ png_alloc_size_t cb = memory->size;
+
+ if (cb > pool->max)
+ store_pool_error(pool->store, pp, "memory corrupted (size)");
+
+ else if (memcmp((png_bytep)(memory+1)+cb, pool->mark, sizeof pool->mark)
+ != 0)
+ store_pool_error(pool->store, pp, "memory corrupted (end)");
+
+ /* Finally give the library a chance to find problems too: */
+ else
+ {
+ pool->current -= cb;
+ free(memory);
+ }
+ }
+}
+
+static void
+store_pool_delete(png_store *ps, store_pool *pool)
+{
+ if (pool->list != NULL)
+ {
+ fprintf(stderr, "%s: %s %s: memory lost (list follows):\n", ps->test,
+ pool == &ps->read_memory_pool ? "read" : "write",
+ pool == &ps->read_memory_pool ? (ps->current != NULL ?
+ ps->current->name : "unknown file") : ps->wname);
+ ++ps->nerrors;
+
+ do
+ {
+ store_memory *next = pool->list;
+ pool->list = next->next;
+ next->next = NULL;
+
+ fprintf(stderr, "\t%lu bytes @ %p\n",
+ (unsigned long)next->size, (PNG_CONST void*)(next+1));
+ /* The NULL means this will always return, even if the memory is
+ * corrupted.
+ */
+ store_memory_free(NULL, pool, next);
+ }
+ while (pool->list != NULL);
+ }
+
+ /* And reset the other fields too for the next time. */
+ if (pool->max > pool->max_max) pool->max_max = pool->max;
+ pool->max = 0;
+ if (pool->current != 0) /* unexpected internal error */
+ fprintf(stderr, "%s: %s %s: memory counter mismatch (internal error)\n",
+ ps->test, pool == &ps->read_memory_pool ? "read" : "write",
+ pool == &ps->read_memory_pool ? (ps->current != NULL ?
+ ps->current->name : "unknown file") : ps->wname);
+ pool->current = 0;
+
+ if (pool->limit > pool->max_limit)
+ pool->max_limit = pool->limit;
+
+ pool->limit = 0;
+
+ if (pool->total > pool->max_total)
+ pool->max_total = pool->total;
+
+ pool->total = 0;
+
+ /* Get a new mark too. */
+ store_pool_mark(pool->mark);
+}
+
+/* The memory callbacks: */
+static png_voidp
+store_malloc(png_structp pp, png_alloc_size_t cb)
+{
+ store_pool *pool = voidcast(store_pool*, png_get_mem_ptr(pp));
+ store_memory *new = voidcast(store_memory*, malloc(cb + (sizeof *new) +
+ (sizeof pool->mark)));
+
+ if (new != NULL)
+ {
+ if (cb > pool->max)
+ pool->max = cb;
+
+ pool->current += cb;
+
+ if (pool->current > pool->limit)
+ pool->limit = pool->current;
+
+ pool->total += cb;
+
+ new->size = cb;
+ memcpy(new->mark, pool->mark, sizeof new->mark);
+ memcpy((png_byte*)(new+1) + cb, pool->mark, sizeof pool->mark);
+ new->pool = pool;
+ new->next = pool->list;
+ pool->list = new;
+ ++new;
+ }
+
+ else
+ {
+ /* NOTE: the PNG user malloc function cannot use the png_ptr it is passed
+ * other than to retrieve the allocation pointer! libpng calls the
+ * store_malloc callback in two basic cases:
+ *
+ * 1) From png_malloc; png_malloc will do a png_error itself if NULL is
+ * returned.
+ * 2) From png_struct or png_info structure creation; png_malloc is
+ * to return so cleanup can be performed.
+ *
+ * To handle this store_malloc can log a message, but can't do anything
+ * else.
+ */
+ store_log(pool->store, pp, "out of memory", 1 /* is_error */);
+ }
+
+ return new;
+}
+
+static void
+store_free(png_structp pp, png_voidp memory)
+{
+ store_pool *pool = voidcast(store_pool*, png_get_mem_ptr(pp));
+ store_memory *this = voidcast(store_memory*, memory), **test;
+
+ /* Because libpng calls store_free with a dummy png_struct when deleting
+ * png_struct or png_info via png_destroy_struct_2 it is necessary to check
+ * the passed in png_structp to ensure it is valid, and not pass it to
+ * png_error if it is not.
+ */
+ if (pp != pool->store->pread && pp != pool->store->pwrite)
+ pp = NULL;
+
+ /* First check that this 'memory' really is valid memory - it must be in the
+ * pool list. If it is, use the shared memory_free function to free it.
+ */
+ --this;
+ for (test = &pool->list; *test != this; test = &(*test)->next)
+ {
+ if (*test == NULL)
+ {
+ store_pool_error(pool->store, pp, "bad pointer to free");
+ return;
+ }
+ }
+
+ /* Unlink this entry, *test == this. */
+ *test = this->next;
+ this->next = NULL;
+ store_memory_free(pp, pool, this);
+}
+
+/* Setup functions. */
+/* Cleanup when aborting a write or after storing the new file. */
+static void
+store_write_reset(png_store *ps)
+{
+ if (ps->pwrite != NULL)
+ {
+ anon_context(ps);
+
+ Try
+ png_destroy_write_struct(&ps->pwrite, &ps->piwrite);
+
+ Catch_anonymous
+ {
+ /* memory corruption: continue. */
+ }
+
+ ps->pwrite = NULL;
+ ps->piwrite = NULL;
+ }
+
+ /* And make sure that all the memory has been freed - this will output
+ * spurious errors in the case of memory corruption above, but this is safe.
+ */
+ store_pool_delete(ps, &ps->write_memory_pool);
+
+ store_freenew(ps);
+}
+
+/* The following is the main write function, it returns a png_struct and,
+ * optionally, a png_info suitable for writiing a new PNG file. Use
+ * store_storefile above to record this file after it has been written. The
+ * returned libpng structures as destroyed by store_write_reset above.
+ */
+static png_structp
+set_store_for_write(png_store *ps, png_infopp ppi,
+ PNG_CONST char * volatile name)
+{
+ anon_context(ps);
+
+ Try
+ {
+ if (ps->pwrite != NULL)
+ png_error(ps->pwrite, "write store already in use");
+
+ store_write_reset(ps);
+ safecat(ps->wname, sizeof ps->wname, 0, name);
+
+ /* Don't do the slow memory checks if doing a speed test. */
+ if (ps->speed)
+ ps->pwrite = png_create_write_struct(PNG_LIBPNG_VER_STRING,
+ ps, store_error, store_warning);
+
+ else
+ ps->pwrite = png_create_write_struct_2(PNG_LIBPNG_VER_STRING,
+ ps, store_error, store_warning, &ps->write_memory_pool,
+ store_malloc, store_free);
+
+ png_set_write_fn(ps->pwrite, ps, store_write, store_flush);
+
+ if (ppi != NULL)
+ *ppi = ps->piwrite = png_create_info_struct(ps->pwrite);
+ }
+
+ Catch_anonymous
+ return NULL;
+
+ return ps->pwrite;
+}
+
+/* Cleanup when finished reading (either due to error or in the success case).
+ */
+static void
+store_read_reset(png_store *ps)
+{
+ if (ps->pread != NULL)
+ {
+ anon_context(ps);
+
+ Try
+ png_destroy_read_struct(&ps->pread, &ps->piread, NULL);
+
+ Catch_anonymous
+ {
+ /* error already output: continue */
+ }
+
+ ps->pread = NULL;
+ ps->piread = NULL;
+ }
+
+ /* Always do this to be safe. */
+ store_pool_delete(ps, &ps->read_memory_pool);
+
+ ps->current = NULL;
+ ps->next = NULL;
+ ps->readpos = 0;
+ ps->validated = 0;
+}
+
+static void
+store_read_set(png_store *ps, png_uint_32 id)
+{
+ png_store_file *pf = ps->saved;
+
+ while (pf != NULL)
+ {
+ if (pf->id == id)
+ {
+ ps->current = pf;
+ ps->next = NULL;
+ store_read_buffer_next(ps);
+ return;
+ }
+
+ pf = pf->next;
+ }
+
+ {
+ size_t pos;
+ char msg[FILE_NAME_SIZE+64];
+
+ pos = standard_name_from_id(msg, sizeof msg, 0, id);
+ pos = safecat(msg, sizeof msg, pos, ": file not found");
+ png_error(ps->pread, msg);
+ }
+}
+
+/* The main interface for reading a saved file - pass the id number of the file
+ * to retrieve. Ids must be unique or the earlier file will be hidden. The API
+ * returns a png_struct and, optionally, a png_info. Both of these will be
+ * destroyed by store_read_reset above.
+ */
+static png_structp
+set_store_for_read(png_store *ps, png_infopp ppi, png_uint_32 id,
+ PNG_CONST char *name)
+{
+ /* Set the name for png_error */
+ safecat(ps->test, sizeof ps->test, 0, name);
+
+ if (ps->pread != NULL)
+ png_error(ps->pread, "read store already in use");
+
+ store_read_reset(ps);
+
+ /* Both the create APIs can return NULL if used in their default mode
+ * (because there is no other way of handling an error because the jmp_buf
+ * by default is stored in png_struct and that has not been allocated!)
+ * However, given that store_error works correctly in these circumstances
+ * we don't ever expect NULL in this program.
+ */
+ if (ps->speed)
+ ps->pread = png_create_read_struct(PNG_LIBPNG_VER_STRING, ps,
+ store_error, store_warning);
+
+ else
+ ps->pread = png_create_read_struct_2(PNG_LIBPNG_VER_STRING, ps,
+ store_error, store_warning, &ps->read_memory_pool, store_malloc,
+ store_free);
+
+ if (ps->pread == NULL)
+ {
+ struct exception_context *the_exception_context = &ps->exception_context;
+
+ store_log(ps, NULL, "png_create_read_struct returned NULL (unexpected)",
+ 1 /*error*/);
+
+ Throw ps;
+ }
+
+ store_read_set(ps, id);
+
+ if (ppi != NULL)
+ *ppi = ps->piread = png_create_info_struct(ps->pread);
+
+ return ps->pread;
+}
+
+/* The overall cleanup of a store simply calls the above then removes all the
+ * saved files. This does not delete the store itself.
+ */
+static void
+store_delete(png_store *ps)
+{
+ store_write_reset(ps);
+ store_read_reset(ps);
+ store_freefile(&ps->saved);
+ store_image_free(ps, NULL);
+}
+
+/*********************** PNG FILE MODIFICATION ON READ ************************/
+/* Files may be modified on read. The following structure contains a complete
+ * png_store together with extra members to handle modification and a special
+ * read callback for libpng. To use this the 'modifications' field must be set
+ * to a list of png_modification structures that actually perform the
+ * modification, otherwise a png_modifier is functionally equivalent to a
+ * png_store. There is a special read function, set_modifier_for_read, which
+ * replaces set_store_for_read.
+ */
+typedef enum modifier_state
+{
+ modifier_start, /* Initial value */
+ modifier_signature, /* Have a signature */
+ modifier_IHDR /* Have an IHDR */
+} modifier_state;
+
+typedef struct CIE_color
+{
+ /* A single CIE tristimulus value, representing the unique response of a
+ * standard observer to a variety of light spectra. The observer recognizes
+ * all spectra that produce this response as the same color, therefore this
+ * is effectively a description of a color.
+ */
+ double X, Y, Z;
+} CIE_color;
+
+static double
+chromaticity_x(CIE_color c)
+{
+ return c.X / (c.X + c.Y + c.Z);
+}
+
+static double
+chromaticity_y(CIE_color c)
+{
+ return c.Y / (c.X + c.Y + c.Z);
+}
+
+typedef struct color_encoding
+{
+ /* A description of an (R,G,B) encoding of color (as defined above); this
+ * includes the actual colors of the (R,G,B) triples (1,0,0), (0,1,0) and
+ * (0,0,1) plus an encoding value that is used to encode the linear
+ * components R, G and B to give the actual values R^gamma, G^gamma and
+ * B^gamma that are stored.
+ */
+ double gamma; /* Encoding (file) gamma of space */
+ CIE_color red, green, blue; /* End points */
+} color_encoding;
+
+static CIE_color
+white_point(PNG_CONST color_encoding *encoding)
+{
+ CIE_color white;
+
+ white.X = encoding->red.X + encoding->green.X + encoding->blue.X;
+ white.Y = encoding->red.Y + encoding->green.Y + encoding->blue.Y;
+ white.Z = encoding->red.Z + encoding->green.Z + encoding->blue.Z;
+
+ return white;
+}
+
+static void
+normalize_color_encoding(color_encoding *encoding)
+{
+ PNG_CONST double whiteY = encoding->red.Y + encoding->green.Y +
+ encoding->blue.Y;
+
+ if (whiteY != 1)
+ {
+ encoding->red.X /= whiteY;
+ encoding->red.Y /= whiteY;
+ encoding->red.Z /= whiteY;
+ encoding->green.X /= whiteY;
+ encoding->green.Y /= whiteY;
+ encoding->green.Z /= whiteY;
+ encoding->blue.X /= whiteY;
+ encoding->blue.Y /= whiteY;
+ encoding->blue.Z /= whiteY;
+ }
+}
+
+static size_t
+safecat_color_encoding(char *buffer, size_t bufsize, size_t pos,
+ PNG_CONST color_encoding *e, double encoding_gamma)
+{
+ if (e != 0)
+ {
+ if (encoding_gamma != 0)
+ pos = safecat(buffer, bufsize, pos, "(");
+ pos = safecat(buffer, bufsize, pos, "R(");
+ pos = safecatd(buffer, bufsize, pos, e->red.X, 4);
+ pos = safecat(buffer, bufsize, pos, ",");
+ pos = safecatd(buffer, bufsize, pos, e->red.Y, 4);
+ pos = safecat(buffer, bufsize, pos, ",");
+ pos = safecatd(buffer, bufsize, pos, e->red.Z, 4);
+ pos = safecat(buffer, bufsize, pos, "),G(");
+ pos = safecatd(buffer, bufsize, pos, e->green.X, 4);
+ pos = safecat(buffer, bufsize, pos, ",");
+ pos = safecatd(buffer, bufsize, pos, e->green.Y, 4);
+ pos = safecat(buffer, bufsize, pos, ",");
+ pos = safecatd(buffer, bufsize, pos, e->green.Z, 4);
+ pos = safecat(buffer, bufsize, pos, "),B(");
+ pos = safecatd(buffer, bufsize, pos, e->blue.X, 4);
+ pos = safecat(buffer, bufsize, pos, ",");
+ pos = safecatd(buffer, bufsize, pos, e->blue.Y, 4);
+ pos = safecat(buffer, bufsize, pos, ",");
+ pos = safecatd(buffer, bufsize, pos, e->blue.Z, 4);
+ pos = safecat(buffer, bufsize, pos, ")");
+ if (encoding_gamma != 0)
+ pos = safecat(buffer, bufsize, pos, ")");
+ }
+
+ if (encoding_gamma != 0)
+ {
+ pos = safecat(buffer, bufsize, pos, "^");
+ pos = safecatd(buffer, bufsize, pos, encoding_gamma, 5);
+ }
+
+ return pos;
+}
+
+typedef struct png_modifier
+{
+ png_store this; /* I am a png_store */
+ struct png_modification *modifications; /* Changes to make */
+
+ modifier_state state; /* My state */
+
+ /* Information from IHDR: */
+ png_byte bit_depth; /* From IHDR */
+ png_byte colour_type; /* From IHDR */
+
+ /* While handling PLTE, IDAT and IEND these chunks may be pended to allow
+ * other chunks to be inserted.
+ */
+ png_uint_32 pending_len;
+ png_uint_32 pending_chunk;
+
+ /* Test values */
+ double *gammas;
+ unsigned int ngammas;
+ unsigned int ngamma_tests; /* Number of gamma tests to run*/
+ double current_gamma; /* 0 if not set */
+ PNG_CONST color_encoding *encodings;
+ unsigned int nencodings;
+ PNG_CONST color_encoding *current_encoding; /* If an encoding has been set */
+ unsigned int encoding_counter; /* For iteration */
+ int encoding_ignored; /* Something overwrote it */
+
+ /* Control variables used to iterate through possible encodings, the
+ * following must be set to 0 and tested by the function that uses the
+ * png_modifier because the modifier only sets it to 1 (true.)
+ */
+ unsigned int repeat :1; /* Repeat this transform test. */
+ unsigned int test_uses_encoding :1;
+
+ /* Lowest sbit to test (libpng fails for sbit < 8) */
+ png_byte sbitlow;
+
+ /* Error control - these are the limits on errors accepted by the gamma tests
+ * below.
+ */
+ double maxout8; /* Maximum output value error */
+ double maxabs8; /* Absolute sample error 0..1 */
+ double maxcalc8; /* Absolute sample error 0..1 */
+ double maxpc8; /* Percentage sample error 0..100% */
+ double maxout16; /* Maximum output value error */
+ double maxabs16; /* Absolute sample error 0..1 */
+ double maxcalc16;/* Absolute sample error 0..1 */
+ double maxpc16; /* Percentage sample error 0..100% */
+
+ /* This is set by transforms that need to allow a higher limit, it is an
+ * internal check on pngvalid to ensure that the calculated error limits are
+ * not ridiculous; without this it is too easy to make a mistake in pngvalid
+ * that allows any value through.
+ */
+ double limit; /* limit on error values, normally 4E-3 */
+
+ /* Log limits - values above this are logged, but not necessarily
+ * warned.
+ */
+ double log8; /* Absolute error in 8 bits to log */
+ double log16; /* Absolute error in 16 bits to log */
+
+ /* Logged 8 and 16 bit errors ('output' values): */
+ double error_gray_2;
+ double error_gray_4;
+ double error_gray_8;
+ double error_gray_16;
+ double error_color_8;
+ double error_color_16;
+ double error_indexed;
+
+ /* Flags: */
+ /* Whether to call png_read_update_info, not png_read_start_image, and how
+ * many times to call it.
+ */
+ int use_update_info;
+
+ /* Whether or not to interlace. */
+ int interlace_type :9; /* int, but must store '1' */
+
+ /* Run the standard tests? */
+ unsigned int test_standard :1;
+
+ /* Run the odd-sized image and interlace read/write tests? */
+ unsigned int test_size :1;
+
+ /* Run tests on reading with a combiniation of transforms, */
+ unsigned int test_transform :1;
+
+ /* When to use the use_input_precision option: */
+ unsigned int use_input_precision :1;
+ unsigned int use_input_precision_sbit :1;
+ unsigned int use_input_precision_16to8 :1;
+
+ /* If set assume that the calculation bit depth is set by the input
+ * precision, not the output precision.
+ */
+ unsigned int calculations_use_input_precision :1;
+
+ /* If set assume that the calculations are done in 16 bits even if both input
+ * and output are 8 bit or less.
+ */
+ unsigned int assume_16_bit_calculations :1;
+
+ /* Which gamma tests to run: */
+ unsigned int test_gamma_threshold :1;
+ unsigned int test_gamma_transform :1; /* main tests */
+ unsigned int test_gamma_sbit :1;
+ unsigned int test_gamma_scale16 :1;
+ unsigned int test_gamma_background :1;
+ unsigned int test_gamma_alpha_mode :1;
+ unsigned int test_gamma_expand16 :1;
+ unsigned int test_exhaustive :1;
+
+ unsigned int log :1; /* Log max error */
+
+ /* Buffer information, the buffer size limits the size of the chunks that can
+ * be modified - they must fit (including header and CRC) into the buffer!
+ */
+ size_t flush; /* Count of bytes to flush */
+ size_t buffer_count; /* Bytes in buffer */
+ size_t buffer_position; /* Position in buffer */
+ png_byte buffer[1024];
+} png_modifier;
+
+/* This returns true if the test should be stopped now because it has already
+ * failed and it is running silently.
+ */
+static int fail(png_modifier *pm)
+{
+ return !pm->log && !pm->this.verbose && (pm->this.nerrors > 0 ||
+ (pm->this.treat_warnings_as_errors && pm->this.nwarnings > 0));
+}
+
+static void
+modifier_init(png_modifier *pm)
+{
+ memset(pm, 0, sizeof *pm);
+ store_init(&pm->this);
+ pm->modifications = NULL;
+ pm->state = modifier_start;
+ pm->sbitlow = 1U;
+ pm->ngammas = 0;
+ pm->ngamma_tests = 0;
+ pm->gammas = 0;
+ pm->current_gamma = 0;
+ pm->encodings = 0;
+ pm->nencodings = 0;
+ pm->current_encoding = 0;
+ pm->encoding_counter = 0;
+ pm->encoding_ignored = 0;
+ pm->repeat = 0;
+ pm->test_uses_encoding = 0;
+ pm->maxout8 = pm->maxpc8 = pm->maxabs8 = pm->maxcalc8 = 0;
+ pm->maxout16 = pm->maxpc16 = pm->maxabs16 = pm->maxcalc16 = 0;
+ pm->limit = 4E-3;
+ pm->log8 = pm->log16 = 0; /* Means 'off' */
+ pm->error_gray_2 = pm->error_gray_4 = pm->error_gray_8 = 0;
+ pm->error_gray_16 = pm->error_color_8 = pm->error_color_16 = 0;
+ pm->error_indexed = 0;
+ pm->use_update_info = 0;
+ pm->interlace_type = PNG_INTERLACE_NONE;
+ pm->test_standard = 0;
+ pm->test_size = 0;
+ pm->test_transform = 0;
+ pm->use_input_precision = 0;
+ pm->use_input_precision_sbit = 0;
+ pm->use_input_precision_16to8 = 0;
+ pm->calculations_use_input_precision = 0;
+ pm->test_gamma_threshold = 0;
+ pm->test_gamma_transform = 0;
+ pm->test_gamma_sbit = 0;
+ pm->test_gamma_scale16 = 0;
+ pm->test_gamma_background = 0;
+ pm->test_gamma_alpha_mode = 0;
+ pm->test_gamma_expand16 = 0;
+ pm->test_exhaustive = 0;
+ pm->log = 0;
+
+ /* Rely on the memset for all the other fields - there are no pointers */
+}
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+/* If pm->calculations_use_input_precision is set then operations will happen
+ * with only 8 bit precision unless both the input and output bit depth are 16.
+ *
+ * If pm->assume_16_bit_calculations is set then even 8 bit calculations use 16
+ * bit precision. This only affects those of the following limits that pertain
+ * to a calculation - not a digitization operation - unless the following API is
+ * called directly.
+ */
+static double digitize(PNG_CONST png_modifier *pm, double value,
+ int sample_depth, int do_round)
+{
+ /* 'value' is in the range 0 to 1, the result is the same value rounded to a
+ * multiple of the digitization factor - 8 or 16 bits depending on both the
+ * sample depth and the 'assume' setting. Digitization is normally by
+ * rounding and 'do_round' should be 1, if it is 0 the digitized value will
+ * be truncated.
+ */
+ PNG_CONST unsigned int digitization_factor =
+ (pm->assume_16_bit_calculations || sample_depth == 16) ? 65535 : 255;
+
+ /* Limiting the range is done as a convenience to the caller - it's easier to
+ * do it once here than every time at the call site.
+ */
+ if (value <= 0)
+ value = 0;
+ else if (value >= 1)
+ value = 1;
+
+ value *= digitization_factor;
+ if (do_round) value += .5;
+ return floor(value)/digitization_factor;
+}
+
+static double abserr(PNG_CONST png_modifier *pm, int in_depth, int out_depth)
+{
+ /* Absolute error permitted in linear values - affected by the bit depth of
+ * the calculations.
+ */
+ if (pm->assume_16_bit_calculations || (out_depth == 16 && (in_depth == 16 ||
+ !pm->calculations_use_input_precision)))
+ return pm->maxabs16;
+ else
+ return pm->maxabs8;
+}
+
+static double calcerr(PNG_CONST png_modifier *pm, int in_depth, int out_depth)
+{
+ /* Error in the linear composition arithmetic - only relevant when
+ * composition actually happens (0 < alpha < 1).
+ */
+ if (pm->assume_16_bit_calculations || (out_depth == 16 && (in_depth == 16 ||
+ !pm->calculations_use_input_precision)))
+ return pm->maxcalc16;
+ else
+ return pm->maxcalc8;
+}
+
+static double pcerr(PNG_CONST png_modifier *pm, int in_depth, int out_depth)
+{
+ /* Percentage error permitted in the linear values. Note that the specified
+ * value is a percentage but this routine returns a simple number.
+ */
+ if (pm->assume_16_bit_calculations || (out_depth == 16 && (in_depth == 16 ||
+ !pm->calculations_use_input_precision)))
+ return pm->maxpc16 * .01;
+ else
+ return pm->maxpc8 * .01;
+}
+
+/* Output error - the error in the encoded value. This is determined by the
+ * digitization of the output so can be +/-0.5 in the actual output value. In
+ * the expand_16 case with the current code in libpng the expand happens after
+ * all the calculations are done in 8 bit arithmetic, so even though the output
+ * depth is 16 the output error is determined by the 8 bit calculation.
+ *
+ * This limit is not determined by the bit depth of internal calculations.
+ *
+ * The specified parameter does *not* include the base .5 digitization error but
+ * it is added here.
+ */
+static double outerr(PNG_CONST png_modifier *pm, int in_depth, int out_depth)
+{
+ /* There is a serious error in the 2 and 4 bit grayscale transform because
+ * the gamma table value (8 bits) is simply shifted, not rounded, so the
+ * error in 4 bit grayscale gamma is up to the value below. This is a hack
+ * to allow pngvalid to succeed:
+ *
+ * TODO: fix this in libpng
+ */
+ if (out_depth == 2)
+ return .73182-.5;
+
+ if (out_depth == 4)
+ return .90644-.5;
+
+ if (out_depth == 16 && (in_depth == 16 ||
+ !pm->calculations_use_input_precision))
+ return pm->maxout16;
+
+ /* This is the case where the value was calculated at 8-bit precision then
+ * scaled to 16 bits.
+ */
+ else if (out_depth == 16)
+ return pm->maxout8 * 257;
+
+ else
+ return pm->maxout8;
+}
+
+/* This does the same thing as the above however it returns the value to log,
+ * rather than raising a warning. This is useful for debugging to track down
+ * exactly what set of parameters cause high error values.
+ */
+static double outlog(PNG_CONST png_modifier *pm, int in_depth, int out_depth)
+{
+ /* The command line parameters are either 8 bit (0..255) or 16 bit (0..65535)
+ * and so must be adjusted for low bit depth grayscale:
+ */
+ if (out_depth <= 8)
+ {
+ if (pm->log8 == 0) /* switched off */
+ return 256;
+
+ if (out_depth < 8)
+ return pm->log8 / 255 * ((1<<out_depth)-1);
+
+ return pm->log8;
+ }
+
+ if (out_depth == 16 && (in_depth == 16 ||
+ !pm->calculations_use_input_precision))
+ {
+ if (pm->log16 == 0)
+ return 65536;
+
+ return pm->log16;
+ }
+
+ /* This is the case where the value was calculated at 8-bit precision then
+ * scaled to 16 bits.
+ */
+ if (pm->log8 == 0)
+ return 65536;
+
+ return pm->log8 * 257;
+}
+
+/* This complements the above by providing the appropriate quantization for the
+ * final value. Normally this would just be quantization to an integral value,
+ * but in the 8 bit calculation case it's actually quantization to a multiple of
+ * 257!
+ */
+static int output_quantization_factor(PNG_CONST png_modifier *pm, int in_depth,
+ int out_depth)
+{
+ if (out_depth == 16 && in_depth != 16
+ && pm->calculations_use_input_precision)
+ return 257;
+ else
+ return 1;
+}
+
+/* One modification structure must be provided for each chunk to be modified (in
+ * fact more than one can be provided if multiple separate changes are desired
+ * for a single chunk.) Modifications include adding a new chunk when a
+ * suitable chunk does not exist.
+ *
+ * The caller of modify_fn will reset the CRC of the chunk and record 'modified'
+ * or 'added' as appropriate if the modify_fn returns 1 (true). If the
+ * modify_fn is NULL the chunk is simply removed.
+ */
+typedef struct png_modification
+{
+ struct png_modification *next;
+ png_uint_32 chunk;
+
+ /* If the following is NULL all matching chunks will be removed: */
+ int (*modify_fn)(struct png_modifier *pm,
+ struct png_modification *me, int add);
+
+ /* If the following is set to PLTE, IDAT or IEND and the chunk has not been
+ * found and modified (and there is a modify_fn) the modify_fn will be called
+ * to add the chunk before the relevant chunk.
+ */
+ png_uint_32 add;
+ unsigned int modified :1; /* Chunk was modified */
+ unsigned int added :1; /* Chunk was added */
+ unsigned int removed :1; /* Chunk was removed */
+} png_modification;
+
+static void
+modification_reset(png_modification *pmm)
+{
+ if (pmm != NULL)
+ {
+ pmm->modified = 0;
+ pmm->added = 0;
+ pmm->removed = 0;
+ modification_reset(pmm->next);
+ }
+}
+
+static void
+modification_init(png_modification *pmm)
+{
+ memset(pmm, 0, sizeof *pmm);
+ pmm->next = NULL;
+ pmm->chunk = 0;
+ pmm->modify_fn = NULL;
+ pmm->add = 0;
+ modification_reset(pmm);
+}
+
+static void
+modifier_current_encoding(PNG_CONST png_modifier *pm, color_encoding *ce)
+{
+ if (pm->current_encoding != 0)
+ *ce = *pm->current_encoding;
+
+ else
+ memset(ce, 0, sizeof *ce);
+
+ ce->gamma = pm->current_gamma;
+}
+
+static size_t
+safecat_current_encoding(char *buffer, size_t bufsize, size_t pos,
+ PNG_CONST png_modifier *pm)
+{
+ pos = safecat_color_encoding(buffer, bufsize, pos, pm->current_encoding,
+ pm->current_gamma);
+
+ if (pm->encoding_ignored)
+ pos = safecat(buffer, bufsize, pos, "[overridden]");
+
+ return pos;
+}
+
+/* Iterate through the usefully testable color encodings. An encoding is one
+ * of:
+ *
+ * 1) Nothing (no color space, no gamma).
+ * 2) Just a gamma value from the gamma array (including 1.0)
+ * 3) A color space from the encodings array with the corresponding gamma.
+ * 4) The same, but with gamma 1.0 (only really useful with 16 bit calculations)
+ *
+ * The iterator selects these in turn, the randomizer selects one at random,
+ * which is used depends on the setting of the 'test_exhaustive' flag. Notice
+ * that this function changes the colour space encoding so it must only be
+ * called on completion of the previous test. This is what 'modifier_reset'
+ * does, below.
+ *
+ * After the function has been called the 'repeat' flag will still be set; the
+ * caller of modifier_reset must reset it at the start of each run of the test!
+ */
+static unsigned int
+modifier_total_encodings(PNG_CONST png_modifier *pm)
+{
+ return 1 + /* (1) nothing */
+ pm->ngammas + /* (2) gamma values to test */
+ pm->nencodings + /* (3) total number of encodings */
+ /* The following test only works after the first time through the
+ * png_modifier code because 'bit_depth' is set when the IHDR is read.
+ * modifier_reset, below, preserves the setting until after it has called
+ * the iterate function (also below.)
+ *
+ * For this reason do not rely on this function outside a call to
+ * modifier_reset.
+ */
+ ((pm->bit_depth == 16 || pm->assume_16_bit_calculations) ?
+ pm->nencodings : 0); /* (4) encodings with gamma == 1.0 */
+}
+
+static void
+modifier_encoding_iterate(png_modifier *pm)
+{
+ if (!pm->repeat && /* Else something needs the current encoding again. */
+ pm->test_uses_encoding) /* Some transform is encoding dependent */
+ {
+ if (pm->test_exhaustive)
+ {
+ if (++pm->encoding_counter >= modifier_total_encodings(pm))
+ pm->encoding_counter = 0; /* This will stop the repeat */
+ }
+
+ else
+ {
+ /* Not exhaustive - choose an encoding at random; generate a number in
+ * the range 1..(max-1), so the result is always non-zero:
+ */
+ if (pm->encoding_counter == 0)
+ pm->encoding_counter = random_mod(modifier_total_encodings(pm)-1)+1;
+ else
+ pm->encoding_counter = 0;
+ }
+
+ if (pm->encoding_counter > 0)
+ pm->repeat = 1;
+ }
+
+ else if (!pm->repeat)
+ pm->encoding_counter = 0;
+}
+
+static void
+modifier_reset(png_modifier *pm)
+{
+ store_read_reset(&pm->this);
+ pm->limit = 4E-3;
+ pm->pending_len = pm->pending_chunk = 0;
+ pm->flush = pm->buffer_count = pm->buffer_position = 0;
+ pm->modifications = NULL;
+ pm->state = modifier_start;
+ modifier_encoding_iterate(pm);
+ /* The following must be set in the next run. In particular
+ * test_uses_encodings must be set in the _ini function of each transform
+ * that looks at the encodings. (Not the 'add' function!)
+ */
+ pm->test_uses_encoding = 0;
+ pm->current_gamma = 0;
+ pm->current_encoding = 0;
+ pm->encoding_ignored = 0;
+ /* These only become value after IHDR is read: */
+ pm->bit_depth = pm->colour_type = 0;
+}
+
+/* The following must be called before anything else to get the encoding set up
+ * on the modifier. In particular it must be called before the transform init
+ * functions are called.
+ */
+static void
+modifier_set_encoding(png_modifier *pm)
+{
+ /* Set the encoding to the one specified by the current encoding counter,
+ * first clear out all the settings - this corresponds to an encoding_counter
+ * of 0.
+ */
+ pm->current_gamma = 0;
+ pm->current_encoding = 0;
+ pm->encoding_ignored = 0; /* not ignored yet - happens in _ini functions. */
+
+ /* Now, if required, set the gamma and encoding fields. */
+ if (pm->encoding_counter > 0)
+ {
+ /* The gammas[] array is an array of screen gammas, not encoding gammas,
+ * so we need the inverse:
+ */
+ if (pm->encoding_counter <= pm->ngammas)
+ pm->current_gamma = 1/pm->gammas[pm->encoding_counter-1];
+
+ else
+ {
+ unsigned int i = pm->encoding_counter - pm->ngammas;
+
+ if (i >= pm->nencodings)
+ {
+ i %= pm->nencodings;
+ pm->current_gamma = 1; /* Linear, only in the 16 bit case */
+ }
+
+ else
+ pm->current_gamma = pm->encodings[i].gamma;
+
+ pm->current_encoding = pm->encodings + i;
+ }
+ }
+}
+
+/* Enquiry functions to find out what is set. Notice that there is an implicit
+ * assumption below that the first encoding in the list is the one for sRGB.
+ */
+static int
+modifier_color_encoding_is_sRGB(PNG_CONST png_modifier *pm)
+{
+ return pm->current_encoding != 0 && pm->current_encoding == pm->encodings &&
+ pm->current_encoding->gamma == pm->current_gamma;
+}
+
+static int
+modifier_color_encoding_is_set(PNG_CONST png_modifier *pm)
+{
+ return pm->current_gamma != 0;
+}
+
+/* Convenience macros. */
+#define CHUNK(a,b,c,d) (((a)<<24)+((b)<<16)+((c)<<8)+(d))
+#define CHUNK_IHDR CHUNK(73,72,68,82)
+#define CHUNK_PLTE CHUNK(80,76,84,69)
+#define CHUNK_IDAT CHUNK(73,68,65,84)
+#define CHUNK_IEND CHUNK(73,69,78,68)
+#define CHUNK_cHRM CHUNK(99,72,82,77)
+#define CHUNK_gAMA CHUNK(103,65,77,65)
+#define CHUNK_sBIT CHUNK(115,66,73,84)
+#define CHUNK_sRGB CHUNK(115,82,71,66)
+
+/* The guts of modification are performed during a read. */
+static void
+modifier_crc(png_bytep buffer)
+{
+ /* Recalculate the chunk CRC - a complete chunk must be in
+ * the buffer, at the start.
+ */
+ uInt datalen = png_get_uint_32(buffer);
+ uLong crc = crc32(0, buffer+4, datalen+4);
+ /* The cast to png_uint_32 is safe because a crc32 is always a 32 bit value.
+ */
+ png_save_uint_32(buffer+datalen+8, (png_uint_32)crc);
+}
+
+static void
+modifier_setbuffer(png_modifier *pm)
+{
+ modifier_crc(pm->buffer);
+ pm->buffer_count = png_get_uint_32(pm->buffer)+12;
+ pm->buffer_position = 0;
+}
+
+/* Separate the callback into the actual implementation (which is passed the
+ * png_modifier explicitly) and the callback, which gets the modifier from the
+ * png_struct.
+ */
+static void
+modifier_read_imp(png_modifier *pm, png_bytep pb, png_size_t st)
+{
+ while (st > 0)
+ {
+ size_t cb;
+ png_uint_32 len, chunk;
+ png_modification *mod;
+
+ if (pm->buffer_position >= pm->buffer_count) switch (pm->state)
+ {
+ static png_byte sign[8] = { 137, 80, 78, 71, 13, 10, 26, 10 };
+ case modifier_start:
+ store_read_imp(&pm->this, pm->buffer, 8); /* size of signature. */
+ pm->buffer_count = 8;
+ pm->buffer_position = 0;
+
+ if (memcmp(pm->buffer, sign, 8) != 0)
+ png_error(pm->this.pread, "invalid PNG file signature");
+ pm->state = modifier_signature;
+ break;
+
+ case modifier_signature:
+ store_read_imp(&pm->this, pm->buffer, 13+12); /* size of IHDR */
+ pm->buffer_count = 13+12;
+ pm->buffer_position = 0;
+
+ if (png_get_uint_32(pm->buffer) != 13 ||
+ png_get_uint_32(pm->buffer+4) != CHUNK_IHDR)
+ png_error(pm->this.pread, "invalid IHDR");
+
+ /* Check the list of modifiers for modifications to the IHDR. */
+ mod = pm->modifications;
+ while (mod != NULL)
+ {
+ if (mod->chunk == CHUNK_IHDR && mod->modify_fn &&
+ (*mod->modify_fn)(pm, mod, 0))
+ {
+ mod->modified = 1;
+ modifier_setbuffer(pm);
+ }
+
+ /* Ignore removal or add if IHDR! */
+ mod = mod->next;
+ }
+
+ /* Cache information from the IHDR (the modified one.) */
+ pm->bit_depth = pm->buffer[8+8];
+ pm->colour_type = pm->buffer[8+8+1];
+
+ pm->state = modifier_IHDR;
+ pm->flush = 0;
+ break;
+
+ case modifier_IHDR:
+ default:
+ /* Read a new chunk and process it until we see PLTE, IDAT or
+ * IEND. 'flush' indicates that there is still some data to
+ * output from the preceding chunk.
+ */
+ if ((cb = pm->flush) > 0)
+ {
+ if (cb > st) cb = st;
+ pm->flush -= cb;
+ store_read_imp(&pm->this, pb, cb);
+ pb += cb;
+ st -= cb;
+ if (st == 0) return;
+ }
+
+ /* No more bytes to flush, read a header, or handle a pending
+ * chunk.
+ */
+ if (pm->pending_chunk != 0)
+ {
+ png_save_uint_32(pm->buffer, pm->pending_len);
+ png_save_uint_32(pm->buffer+4, pm->pending_chunk);
+ pm->pending_len = 0;
+ pm->pending_chunk = 0;
+ }
+ else
+ store_read_imp(&pm->this, pm->buffer, 8);
+
+ pm->buffer_count = 8;
+ pm->buffer_position = 0;
+
+ /* Check for something to modify or a terminator chunk. */
+ len = png_get_uint_32(pm->buffer);
+ chunk = png_get_uint_32(pm->buffer+4);
+
+ /* Terminators first, they may have to be delayed for added
+ * chunks
+ */
+ if (chunk == CHUNK_PLTE || chunk == CHUNK_IDAT ||
+ chunk == CHUNK_IEND)
+ {
+ mod = pm->modifications;
+
+ while (mod != NULL)
+ {
+ if ((mod->add == chunk ||
+ (mod->add == CHUNK_PLTE && chunk == CHUNK_IDAT)) &&
+ mod->modify_fn != NULL && !mod->modified && !mod->added)
+ {
+ /* Regardless of what the modify function does do not run
+ * this again.
+ */
+ mod->added = 1;
+
+ if ((*mod->modify_fn)(pm, mod, 1 /*add*/))
+ {
+ /* Reset the CRC on a new chunk */
+ if (pm->buffer_count > 0)
+ modifier_setbuffer(pm);
+
+ else
+ {
+ pm->buffer_position = 0;
+ mod->removed = 1;
+ }
+
+ /* The buffer has been filled with something (we assume)
+ * so output this. Pend the current chunk.
+ */
+ pm->pending_len = len;
+ pm->pending_chunk = chunk;
+ break; /* out of while */
+ }
+ }
+
+ mod = mod->next;
+ }
+
+ /* Don't do any further processing if the buffer was modified -
+ * otherwise the code will end up modifying a chunk that was
+ * just added.
+ */
+ if (mod != NULL)
+ break; /* out of switch */
+ }
+
+ /* If we get to here then this chunk may need to be modified. To
+ * do this it must be less than 1024 bytes in total size, otherwise
+ * it just gets flushed.
+ */
+ if (len+12 <= sizeof pm->buffer)
+ {
+ store_read_imp(&pm->this, pm->buffer+pm->buffer_count,
+ len+12-pm->buffer_count);
+ pm->buffer_count = len+12;
+
+ /* Check for a modification, else leave it be. */
+ mod = pm->modifications;
+ while (mod != NULL)
+ {
+ if (mod->chunk == chunk)
+ {
+ if (mod->modify_fn == NULL)
+ {
+ /* Remove this chunk */
+ pm->buffer_count = pm->buffer_position = 0;
+ mod->removed = 1;
+ break; /* Terminate the while loop */
+ }
+
+ else if ((*mod->modify_fn)(pm, mod, 0))
+ {
+ mod->modified = 1;
+ /* The chunk may have been removed: */
+ if (pm->buffer_count == 0)
+ {
+ pm->buffer_position = 0;
+ break;
+ }
+ modifier_setbuffer(pm);
+ }
+ }
+
+ mod = mod->next;
+ }
+ }
+
+ else
+ pm->flush = len+12 - pm->buffer_count; /* data + crc */
+
+ /* Take the data from the buffer (if there is any). */
+ break;
+ }
+
+ /* Here to read from the modifier buffer (not directly from
+ * the store, as in the flush case above.)
+ */
+ cb = pm->buffer_count - pm->buffer_position;
+
+ if (cb > st)
+ cb = st;
+
+ memcpy(pb, pm->buffer + pm->buffer_position, cb);
+ st -= cb;
+ pb += cb;
+ pm->buffer_position += cb;
+ }
+}
+
+/* The callback: */
+static void
+modifier_read(png_structp pp, png_bytep pb, png_size_t st)
+{
+ png_modifier *pm = voidcast(png_modifier*, png_get_io_ptr(pp));
+
+ if (pm == NULL || pm->this.pread != pp)
+ png_error(pp, "bad modifier_read call");
+
+ modifier_read_imp(pm, pb, st);
+}
+
+/* Like store_progressive_read but the data is getting changed as we go so we
+ * need a local buffer.
+ */
+static void
+modifier_progressive_read(png_modifier *pm, png_structp pp, png_infop pi)
+{
+ if (pm->this.pread != pp || pm->this.current == NULL ||
+ pm->this.next == NULL)
+ png_error(pp, "store state damaged (progressive)");
+
+ /* This is another Horowitz and Hill random noise generator. In this case
+ * the aim is to stress the progressive reader with truly horrible variable
+ * buffer sizes in the range 1..500, so a sequence of 9 bit random numbers
+ * is generated. We could probably just count from 1 to 32767 and get as
+ * good a result.
+ */
+ for (;;)
+ {
+ static png_uint_32 noise = 1;
+ png_size_t cb, cbAvail;
+ png_byte buffer[512];
+
+ /* Generate 15 more bits of stuff: */
+ noise = (noise << 9) | ((noise ^ (noise >> (9-5))) & 0x1ff);
+ cb = noise & 0x1ff;
+
+ /* Check that this number of bytes are available (in the current buffer.)
+ * (This doesn't quite work - the modifier might delete a chunk; unlikely
+ * but possible, it doesn't happen at present because the modifier only
+ * adds chunks to standard images.)
+ */
+ cbAvail = store_read_buffer_avail(&pm->this);
+ if (pm->buffer_count > pm->buffer_position)
+ cbAvail += pm->buffer_count - pm->buffer_position;
+
+ if (cb > cbAvail)
+ {
+ /* Check for EOF: */
+ if (cbAvail == 0)
+ break;
+
+ cb = cbAvail;
+ }
+
+ modifier_read_imp(pm, buffer, cb);
+ png_process_data(pp, pi, buffer, cb);
+ }
+
+ /* Check the invariants at the end (if this fails it's a problem in this
+ * file!)
+ */
+ if (pm->buffer_count > pm->buffer_position ||
+ pm->this.next != &pm->this.current->data ||
+ pm->this.readpos < pm->this.current->datacount)
+ png_error(pp, "progressive read implementation error");
+}
+
+/* Set up a modifier. */
+static png_structp
+set_modifier_for_read(png_modifier *pm, png_infopp ppi, png_uint_32 id,
+ PNG_CONST char *name)
+{
+ /* Do this first so that the modifier fields are cleared even if an error
+ * happens allocating the png_struct. No allocation is done here so no
+ * cleanup is required.
+ */
+ pm->state = modifier_start;
+ pm->bit_depth = 0;
+ pm->colour_type = 255;
+
+ pm->pending_len = 0;
+ pm->pending_chunk = 0;
+ pm->flush = 0;
+ pm->buffer_count = 0;
+ pm->buffer_position = 0;
+
+ return set_store_for_read(&pm->this, ppi, id, name);
+}
+
+
+/******************************** MODIFICATIONS *******************************/
+/* Standard modifications to add chunks. These do not require the _SUPPORTED
+ * macros because the chunks can be there regardless of whether this specific
+ * libpng supports them.
+ */
+typedef struct gama_modification
+{
+ png_modification this;
+ png_fixed_point gamma;
+} gama_modification;
+
+static int
+gama_modify(png_modifier *pm, png_modification *me, int add)
+{
+ UNUSED(add)
+ /* This simply dumps the given gamma value into the buffer. */
+ png_save_uint_32(pm->buffer, 4);
+ png_save_uint_32(pm->buffer+4, CHUNK_gAMA);
+ png_save_uint_32(pm->buffer+8, ((gama_modification*)me)->gamma);
+ return 1;
+}
+
+static void
+gama_modification_init(gama_modification *me, png_modifier *pm, double gammad)
+{
+ double g;
+
+ modification_init(&me->this);
+ me->this.chunk = CHUNK_gAMA;
+ me->this.modify_fn = gama_modify;
+ me->this.add = CHUNK_PLTE;
+ g = fix(gammad);
+ me->gamma = (png_fixed_point)g;
+ me->this.next = pm->modifications;
+ pm->modifications = &me->this;
+}
+
+typedef struct chrm_modification
+{
+ png_modification this;
+ PNG_CONST color_encoding *encoding;
+ png_fixed_point wx, wy, rx, ry, gx, gy, bx, by;
+} chrm_modification;
+
+static int
+chrm_modify(png_modifier *pm, png_modification *me, int add)
+{
+ UNUSED(add)
+ /* As with gAMA this just adds the required cHRM chunk to the buffer. */
+ png_save_uint_32(pm->buffer , 32);
+ png_save_uint_32(pm->buffer+ 4, CHUNK_cHRM);
+ png_save_uint_32(pm->buffer+ 8, ((chrm_modification*)me)->wx);
+ png_save_uint_32(pm->buffer+12, ((chrm_modification*)me)->wy);
+ png_save_uint_32(pm->buffer+16, ((chrm_modification*)me)->rx);
+ png_save_uint_32(pm->buffer+20, ((chrm_modification*)me)->ry);
+ png_save_uint_32(pm->buffer+24, ((chrm_modification*)me)->gx);
+ png_save_uint_32(pm->buffer+28, ((chrm_modification*)me)->gy);
+ png_save_uint_32(pm->buffer+32, ((chrm_modification*)me)->bx);
+ png_save_uint_32(pm->buffer+36, ((chrm_modification*)me)->by);
+ return 1;
+}
+
+static void
+chrm_modification_init(chrm_modification *me, png_modifier *pm,
+ PNG_CONST color_encoding *encoding)
+{
+ CIE_color white = white_point(encoding);
+
+ /* Original end points: */
+ me->encoding = encoding;
+
+ /* Chromaticities (in fixed point): */
+ me->wx = fix(chromaticity_x(white));
+ me->wy = fix(chromaticity_y(white));
+
+ me->rx = fix(chromaticity_x(encoding->red));
+ me->ry = fix(chromaticity_y(encoding->red));
+ me->gx = fix(chromaticity_x(encoding->green));
+ me->gy = fix(chromaticity_y(encoding->green));
+ me->bx = fix(chromaticity_x(encoding->blue));
+ me->by = fix(chromaticity_y(encoding->blue));
+
+ modification_init(&me->this);
+ me->this.chunk = CHUNK_cHRM;
+ me->this.modify_fn = chrm_modify;
+ me->this.add = CHUNK_PLTE;
+ me->this.next = pm->modifications;
+ pm->modifications = &me->this;
+}
+
+typedef struct srgb_modification
+{
+ png_modification this;
+ png_byte intent;
+} srgb_modification;
+
+static int
+srgb_modify(png_modifier *pm, png_modification *me, int add)
+{
+ UNUSED(add)
+ /* As above, ignore add and just make a new chunk */
+ png_save_uint_32(pm->buffer, 1);
+ png_save_uint_32(pm->buffer+4, CHUNK_sRGB);
+ pm->buffer[8] = ((srgb_modification*)me)->intent;
+ return 1;
+}
+
+static void
+srgb_modification_init(srgb_modification *me, png_modifier *pm, png_byte intent)
+{
+ modification_init(&me->this);
+ me->this.chunk = CHUNK_sBIT;
+
+ if (intent <= 3) /* if valid, else *delete* sRGB chunks */
+ {
+ me->this.modify_fn = srgb_modify;
+ me->this.add = CHUNK_PLTE;
+ me->intent = intent;
+ }
+
+ else
+ {
+ me->this.modify_fn = 0;
+ me->this.add = 0;
+ me->intent = 0;
+ }
+
+ me->this.next = pm->modifications;
+ pm->modifications = &me->this;
+}
+
+typedef struct sbit_modification
+{
+ png_modification this;
+ png_byte sbit;
+} sbit_modification;
+
+static int
+sbit_modify(png_modifier *pm, png_modification *me, int add)
+{
+ png_byte sbit = ((sbit_modification*)me)->sbit;
+ if (pm->bit_depth > sbit)
+ {
+ int cb = 0;
+ switch (pm->colour_type)
+ {
+ case 0:
+ cb = 1;
+ break;
+
+ case 2:
+ case 3:
+ cb = 3;
+ break;
+
+ case 4:
+ cb = 2;
+ break;
+
+ case 6:
+ cb = 4;
+ break;
+
+ default:
+ png_error(pm->this.pread,
+ "unexpected colour type in sBIT modification");
+ }
+
+ png_save_uint_32(pm->buffer, cb);
+ png_save_uint_32(pm->buffer+4, CHUNK_sBIT);
+
+ while (cb > 0)
+ (pm->buffer+8)[--cb] = sbit;
+
+ return 1;
+ }
+ else if (!add)
+ {
+ /* Remove the sBIT chunk */
+ pm->buffer_count = pm->buffer_position = 0;
+ return 1;
+ }
+ else
+ return 0; /* do nothing */
+}
+
+static void
+sbit_modification_init(sbit_modification *me, png_modifier *pm, png_byte sbit)
+{
+ modification_init(&me->this);
+ me->this.chunk = CHUNK_sBIT;
+ me->this.modify_fn = sbit_modify;
+ me->this.add = CHUNK_PLTE;
+ me->sbit = sbit;
+ me->this.next = pm->modifications;
+ pm->modifications = &me->this;
+}
+#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
+
+/***************************** STANDARD PNG FILES *****************************/
+/* Standard files - write and save standard files. */
+/* There are two basic forms of standard images. Those which attempt to have
+ * all the possible pixel values (not possible for 16bpp images, but a range of
+ * values are produced) and those which have a range of image sizes. The former
+ * are used for testing transforms, in particular gamma correction and bit
+ * reduction and increase. The latter are reserved for testing the behavior of
+ * libpng with respect to 'odd' image sizes - particularly small images where
+ * rows become 1 byte and interlace passes disappear.
+ *
+ * The first, most useful, set are the 'transform' images, the second set of
+ * small images are the 'size' images.
+ *
+ * The transform files are constructed with rows which fit into a 1024 byte row
+ * buffer. This makes allocation easier below. Further regardless of the file
+ * format every row has 128 pixels (giving 1024 bytes for 64bpp formats).
+ *
+ * Files are stored with no gAMA or sBIT chunks, with a PLTE only when needed
+ * and with an ID derived from the colour type, bit depth and interlace type
+ * as above (FILEID). The width (128) and height (variable) are not stored in
+ * the FILEID - instead the fields are set to 0, indicating a transform file.
+ *
+ * The size files ar constructed with rows a maximum of 128 bytes wide, allowing
+ * a maximum width of 16 pixels (for the 64bpp case.) They also have a maximum
+ * height of 16 rows. The width and height are stored in the FILEID and, being
+ * non-zero, indicate a size file.
+ *
+ * For palette image (colour type 3) multiple transform images are stored with
+ * the same bit depth to allow testing of more colour combinations -
+ * particularly important for testing the gamma code because libpng uses a
+ * different code path for palette images. For size images a single palette is
+ * used.
+ */
+
+/* Make a 'standard' palette. Because there are only 256 entries in a palette
+ * (maximum) this actually makes a random palette in the hope that enough tests
+ * will catch enough errors. (Note that the same palette isn't produced every
+ * time for the same test - it depends on what previous tests have been run -
+ * but a given set of arguments to pngvalid will always produce the same palette
+ * at the same test! This is why pseudo-random number generators are useful for
+ * testing.)
+ *
+ * The store must be open for write when this is called, otherwise an internal
+ * error will occur. This routine contains its own magic number seed, so the
+ * palettes generated don't change if there are intervening errors (changing the
+ * calls to the store_mark seed.)
+ */
+static store_palette_entry *
+make_standard_palette(png_store* ps, int npalette, int do_tRNS)
+{
+ static png_uint_32 palette_seed[2] = { 0x87654321, 9 };
+
+ int i = 0;
+ png_byte values[256][4];
+
+ /* Always put in black and white plus the six primary and secondary colors.
+ */
+ for (; i<8; ++i)
+ {
+ values[i][1] = (i&1) ? 255 : 0;
+ values[i][2] = (i&2) ? 255 : 0;
+ values[i][3] = (i&4) ? 255 : 0;
+ }
+
+ /* Then add 62 grays (one quarter of the remaining 256 slots). */
+ {
+ int j = 0;
+ png_byte random_bytes[4];
+ png_byte need[256];
+
+ need[0] = 0; /*got black*/
+ memset(need+1, 1, (sizeof need)-2); /*need these*/
+ need[255] = 0; /*but not white*/
+
+ while (i<70)
+ {
+ png_byte b;
+
+ if (j==0)
+ {
+ make_four_random_bytes(palette_seed, random_bytes);
+ j = 4;
+ }
+
+ b = random_bytes[--j];
+ if (need[b])
+ {
+ values[i][1] = b;
+ values[i][2] = b;
+ values[i++][3] = b;
+ }
+ }
+ }
+
+ /* Finally add 192 colors at random - don't worry about matches to things we
+ * already have, chance is less than 1/65536. Don't worry about grays,
+ * chance is the same, so we get a duplicate or extra gray less than 1 time
+ * in 170.
+ */
+ for (; i<256; ++i)
+ make_four_random_bytes(palette_seed, values[i]);
+
+ /* Fill in the alpha values in the first byte. Just use all possible values
+ * (0..255) in an apparently random order:
+ */
+ {
+ store_palette_entry *palette;
+ png_byte selector[4];
+
+ make_four_random_bytes(palette_seed, selector);
+
+ if (do_tRNS)
+ for (i=0; i<256; ++i)
+ values[i][0] = (png_byte)(i ^ selector[0]);
+
+ else
+ for (i=0; i<256; ++i)
+ values[i][0] = 255; /* no transparency/tRNS chunk */
+
+ /* 'values' contains 256 ARGB values, but we only need 'npalette'.
+ * 'npalette' will always be a power of 2: 2, 4, 16 or 256. In the low
+ * bit depth cases select colors at random, else it is difficult to have
+ * a set of low bit depth palette test with any chance of a reasonable
+ * range of colors. Do this by randomly permuting values into the low
+ * 'npalette' entries using an XOR mask generated here. This also
+ * permutes the npalette == 256 case in a potentially useful way (there is
+ * no relationship between palette index and the color value therein!)
+ */
+ palette = store_write_palette(ps, npalette);
+
+ for (i=0; i<npalette; ++i)
+ {
+ palette[i].alpha = values[i ^ selector[1]][0];
+ palette[i].red = values[i ^ selector[1]][1];
+ palette[i].green = values[i ^ selector[1]][2];
+ palette[i].blue = values[i ^ selector[1]][3];
+ }
+
+ return palette;
+ }
+}
+
+/* Initialize a standard palette on a write stream. The 'do_tRNS' argument
+ * indicates whether or not to also set the tRNS chunk.
+ */
+static void
+init_standard_palette(png_store *ps, png_structp pp, png_infop pi, int npalette,
+ int do_tRNS)
+{
+ store_palette_entry *ppal = make_standard_palette(ps, npalette, do_tRNS);
+
+ {
+ int i;
+ png_color palette[256];
+
+ /* Set all entries to detect overread errors. */
+ for (i=0; i<npalette; ++i)
+ {
+ palette[i].red = ppal[i].red;
+ palette[i].green = ppal[i].green;
+ palette[i].blue = ppal[i].blue;
+ }
+
+ /* Just in case fill in the rest with detectable values: */
+ for (; i<256; ++i)
+ palette[i].red = palette[i].green = palette[i].blue = 42;
+
+ png_set_PLTE(pp, pi, palette, npalette);
+ }
+
+ if (do_tRNS)
+ {
+ int i, j;
+ png_byte tRNS[256];
+
+ /* Set all the entries, but skip trailing opaque entries */
+ for (i=j=0; i<npalette; ++i)
+ if ((tRNS[i] = ppal[i].alpha) < 255)
+ j = i+1;
+
+ /* Fill in the remainder with a detectable value: */
+ for (; i<256; ++i)
+ tRNS[i] = 24;
+
+ if (j > 0)
+ png_set_tRNS(pp, pi, tRNS, j, 0/*color*/);
+ }
+}
+
+/* The number of passes is related to the interlace type. There was no libpng
+ * API to determine this prior to 1.5, so we need an inquiry function:
+ */
+static int
+npasses_from_interlace_type(png_structp pp, int interlace_type)
+{
+ switch (interlace_type)
+ {
+ default:
+ png_error(pp, "invalid interlace type");
+
+ case PNG_INTERLACE_NONE:
+ return 1;
+
+ case PNG_INTERLACE_ADAM7:
+ return PNG_INTERLACE_ADAM7_PASSES;
+ }
+}
+
+static unsigned int
+bit_size(png_structp pp, png_byte colour_type, png_byte bit_depth)
+{
+ switch (colour_type)
+ {
+ default: png_error(pp, "invalid color type");
+
+ case 0: return bit_depth;
+
+ case 2: return 3*bit_depth;
+
+ case 3: return bit_depth;
+
+ case 4: return 2*bit_depth;
+
+ case 6: return 4*bit_depth;
+ }
+}
+
+#define TRANSFORM_WIDTH 128U
+#define TRANSFORM_ROWMAX (TRANSFORM_WIDTH*8U)
+#define SIZE_ROWMAX (16*8U) /* 16 pixels, max 8 bytes each - 128 bytes */
+#define STANDARD_ROWMAX TRANSFORM_ROWMAX /* The larger of the two */
+#define SIZE_HEIGHTMAX 16 /* Maximum range of size images */
+
+static size_t
+transform_rowsize(png_structp pp, png_byte colour_type, png_byte bit_depth)
+{
+ return (TRANSFORM_WIDTH * bit_size(pp, colour_type, bit_depth)) / 8;
+}
+
+/* transform_width(pp, colour_type, bit_depth) current returns the same number
+ * every time, so just use a macro:
+ */
+#define transform_width(pp, colour_type, bit_depth) TRANSFORM_WIDTH
+
+static png_uint_32
+transform_height(png_structp pp, png_byte colour_type, png_byte bit_depth)
+{
+ switch (bit_size(pp, colour_type, bit_depth))
+ {
+ case 1:
+ case 2:
+ case 4:
+ return 1; /* Total of 128 pixels */
+
+ case 8:
+ return 2; /* Total of 256 pixels/bytes */
+
+ case 16:
+ return 512; /* Total of 65536 pixels */
+
+ case 24:
+ case 32:
+ return 512; /* 65536 pixels */
+
+ case 48:
+ case 64:
+ return 2048;/* 4 x 65536 pixels. */
+# define TRANSFORM_HEIGHTMAX 2048
+
+ default:
+ return 0; /* Error, will be caught later */
+ }
+}
+
+/* The following can only be defined here, now we have the definitions
+ * of the transform image sizes.
+ */
+static png_uint_32
+standard_width(png_structp pp, png_uint_32 id)
+{
+ png_uint_32 width = WIDTH_FROM_ID(id);
+ UNUSED(pp)
+
+ if (width == 0)
+ width = transform_width(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id));
+
+ return width;
+}
+
+static png_uint_32
+standard_height(png_structp pp, png_uint_32 id)
+{
+ png_uint_32 height = HEIGHT_FROM_ID(id);
+
+ if (height == 0)
+ height = transform_height(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id));
+
+ return height;
+}
+
+static png_uint_32
+standard_rowsize(png_structp pp, png_uint_32 id)
+{
+ png_uint_32 width = standard_width(pp, id);
+
+ /* This won't overflow: */
+ width *= bit_size(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id));
+ return (width + 7) / 8;
+}
+
+static void
+transform_row(png_structp pp, png_byte buffer[TRANSFORM_ROWMAX],
+ png_byte colour_type, png_byte bit_depth, png_uint_32 y)
+{
+ png_uint_32 v = y << 7;
+ png_uint_32 i = 0;
+
+ switch (bit_size(pp, colour_type, bit_depth))
+ {
+ case 1:
+ while (i<128/8) buffer[i] = v & 0xff, v += 17, ++i;
+ return;
+
+ case 2:
+ while (i<128/4) buffer[i] = v & 0xff, v += 33, ++i;
+ return;
+
+ case 4:
+ while (i<128/2) buffer[i] = v & 0xff, v += 65, ++i;
+ return;
+
+ case 8:
+ /* 256 bytes total, 128 bytes in each row set as follows: */
+ while (i<128) buffer[i] = v & 0xff, ++v, ++i;
+ return;
+
+ case 16:
+ /* Generate all 65536 pixel values in order, which includes the 8 bit
+ * GA case as well as the 16 bit G case.
+ */
+ while (i<128)
+ buffer[2*i] = (v>>8) & 0xff, buffer[2*i+1] = v & 0xff, ++v, ++i;
+
+ return;
+
+ case 24:
+ /* 65535 pixels, but rotate the values. */
+ while (i<128)
+ {
+ /* Three bytes per pixel, r, g, b, make b by r^g */
+ buffer[3*i+0] = (v >> 8) & 0xff;
+ buffer[3*i+1] = v & 0xff;
+ buffer[3*i+2] = ((v >> 8) ^ v) & 0xff;
+ ++v;
+ ++i;
+ }
+
+ return;
+
+ case 32:
+ /* 65535 pixels, r, g, b, a; just replicate */
+ while (i<128)
+ {
+ buffer[4*i+0] = (v >> 8) & 0xff;
+ buffer[4*i+1] = v & 0xff;
+ buffer[4*i+2] = (v >> 8) & 0xff;
+ buffer[4*i+3] = v & 0xff;
+ ++v;
+ ++i;
+ }
+
+ return;
+
+ case 48:
+ /* y is maximum 2047, giving 4x65536 pixels, make 'r' increase by 1 at
+ * each pixel, g increase by 257 (0x101) and 'b' by 0x1111:
+ */
+ while (i<128)
+ {
+ png_uint_32 t = v++;
+ buffer[6*i+0] = (t >> 8) & 0xff;
+ buffer[6*i+1] = t & 0xff;
+ t *= 257;
+ buffer[6*i+2] = (t >> 8) & 0xff;
+ buffer[6*i+3] = t & 0xff;
+ t *= 17;
+ buffer[6*i+4] = (t >> 8) & 0xff;
+ buffer[6*i+5] = t & 0xff;
+ ++i;
+ }
+
+ return;
+
+ case 64:
+ /* As above in the 32 bit case. */
+ while (i<128)
+ {
+ png_uint_32 t = v++;
+ buffer[8*i+0] = (t >> 8) & 0xff;
+ buffer[8*i+1] = t & 0xff;
+ buffer[8*i+4] = (t >> 8) & 0xff;
+ buffer[8*i+5] = t & 0xff;
+ t *= 257;
+ buffer[8*i+2] = (t >> 8) & 0xff;
+ buffer[8*i+3] = t & 0xff;
+ buffer[8*i+6] = (t >> 8) & 0xff;
+ buffer[8*i+7] = t & 0xff;
+ ++i;
+ }
+ return;
+
+ default:
+ break;
+ }
+
+ png_error(pp, "internal error");
+}
+
+/* This is just to do the right cast - could be changed to a function to check
+ * 'bd' but there isn't much point.
+ */
+#define DEPTH(bd) ((png_byte)(1U << (bd)))
+
+/* Make a standardized image given a an image colour type, bit depth and
+ * interlace type. The standard images have a very restricted range of
+ * rows and heights and are used for testing transforms rather than image
+ * layout details. See make_size_images below for a way to make images
+ * that test odd sizes along with the libpng interlace handling.
+ */
+static void
+make_transform_image(png_store* PNG_CONST ps, png_byte PNG_CONST colour_type,
+ png_byte PNG_CONST bit_depth, int palette_number, int interlace_type,
+ png_const_charp name)
+{
+ context(ps, fault);
+
+ Try
+ {
+ png_infop pi;
+ png_structp pp = set_store_for_write(ps, &pi, name);
+ png_uint_32 h;
+
+ /* In the event of a problem return control to the Catch statement below
+ * to do the clean up - it is not possible to 'return' directly from a Try
+ * block.
+ */
+ if (pp == NULL)
+ Throw ps;
+
+ h = transform_height(pp, colour_type, bit_depth);
+
+ png_set_IHDR(pp, pi, transform_width(pp, colour_type, bit_depth), h,
+ bit_depth, colour_type, interlace_type,
+ PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+
+#ifdef PNG_TEXT_SUPPORTED
+ {
+ static char key[] = "image name"; /* must be writeable */
+ size_t pos;
+ png_text text;
+ char copy[FILE_NAME_SIZE];
+
+ /* Use a compressed text string to test the correct interaction of text
+ * compression and IDAT compression.
+ */
+ text.compression = PNG_TEXT_COMPRESSION_zTXt;
+ text.key = key;
+ /* Yuck: the text must be writable! */
+ pos = safecat(copy, sizeof copy, 0, ps->wname);
+ text.text = copy;
+ text.text_length = pos;
+ text.itxt_length = 0;
+ text.lang = 0;
+ text.lang_key = 0;
+
+ png_set_text(pp, pi, &text, 1);
+ }
+#endif
+
+ if (colour_type == 3) /* palette */
+ init_standard_palette(ps, pp, pi, 1U << bit_depth, 1/*do tRNS*/);
+
+ png_write_info(pp, pi);
+
+ if (png_get_rowbytes(pp, pi) !=
+ transform_rowsize(pp, colour_type, bit_depth))
+ png_error(pp, "row size incorrect");
+
+ else
+ {
+ /* Somewhat confusingly this must be called *after* png_write_info
+ * because if it is called before, the information in *pp has not been
+ * updated to reflect the interlaced image.
+ */
+ int npasses = png_set_interlace_handling(pp);
+ int pass;
+
+ if (npasses != npasses_from_interlace_type(pp, interlace_type))
+ png_error(pp, "write: png_set_interlace_handling failed");
+
+ for (pass=0; pass<npasses; ++pass)
+ {
+ png_uint_32 y;
+
+ for (y=0; y<h; ++y)
+ {
+ png_byte buffer[TRANSFORM_ROWMAX];
+
+ transform_row(pp, buffer, colour_type, bit_depth, y);
+ png_write_row(pp, buffer);
+ }
+ }
+ }
+
+#ifdef PNG_TEXT_SUPPORTED
+ {
+ static char key[] = "end marker";
+ static char comment[] = "end";
+ png_text text;
+
+ /* Use a compressed text string to test the correct interaction of text
+ * compression and IDAT compression.
+ */
+ text.compression = PNG_TEXT_COMPRESSION_zTXt;
+ text.key = key;
+ text.text = comment;
+ text.text_length = (sizeof comment)-1;
+ text.itxt_length = 0;
+ text.lang = 0;
+ text.lang_key = 0;
+
+ png_set_text(pp, pi, &text, 1);
+ }
+#endif
+
+ png_write_end(pp, pi);
+
+ /* And store this under the appropriate id, then clean up. */
+ store_storefile(ps, FILEID(colour_type, bit_depth, palette_number,
+ interlace_type, 0, 0, 0));
+
+ store_write_reset(ps);
+ }
+
+ Catch(fault)
+ {
+ /* Use the png_store returned by the exception. This may help the compiler
+ * because 'ps' is not used in this branch of the setjmp. Note that fault
+ * and ps will always be the same value.
+ */
+ store_write_reset(fault);
+ }
+}
+
+static void
+make_transform_images(png_store *ps)
+{
+ png_byte colour_type = 0;
+ png_byte bit_depth = 0;
+ int palette_number = 0;
+
+ /* This is in case of errors. */
+ safecat(ps->test, sizeof ps->test, 0, "make standard images");
+
+ /* Use next_format to enumerate all the combinations we test, including
+ * generating multiple low bit depth palette images.
+ */
+ while (next_format(&colour_type, &bit_depth, &palette_number))
+ {
+ int interlace_type;
+
+ for (interlace_type = PNG_INTERLACE_NONE;
+ interlace_type < PNG_INTERLACE_LAST; ++interlace_type)
+ {
+ char name[FILE_NAME_SIZE];
+
+ standard_name(name, sizeof name, 0, colour_type, bit_depth,
+ palette_number, interlace_type, 0, 0, 0);
+ make_transform_image(ps, colour_type, bit_depth, palette_number,
+ interlace_type, name);
+ }
+ }
+}
+
+/* The following two routines use the PNG interlace support macros from
+ * png.h to interlace or deinterlace rows.
+ */
+static void
+interlace_row(png_bytep buffer, png_const_bytep imageRow,
+ unsigned int pixel_size, png_uint_32 w, int pass)
+{
+ png_uint_32 xin, xout, xstep;
+
+ /* Note that this can, trivially, be optimized to a memcpy on pass 7, the
+ * code is presented this way to make it easier to understand. In practice
+ * consult the code in the libpng source to see other ways of doing this.
+ */
+ xin = PNG_PASS_START_COL(pass);
+ xstep = 1U<<PNG_PASS_COL_SHIFT(pass);
+
+ for (xout=0; xin<w; xin+=xstep)
+ {
+ pixel_copy(buffer, xout, imageRow, xin, pixel_size);
+ ++xout;
+ }
+}
+
+static void
+deinterlace_row(png_bytep buffer, png_const_bytep row,
+ unsigned int pixel_size, png_uint_32 w, int pass)
+{
+ /* The inverse of the above, 'row' is part of row 'y' of the output image,
+ * in 'buffer'. The image is 'w' wide and this is pass 'pass', distribute
+ * the pixels of row into buffer and return the number written (to allow
+ * this to be checked).
+ */
+ png_uint_32 xin, xout, xstep;
+
+ xout = PNG_PASS_START_COL(pass);
+ xstep = 1U<<PNG_PASS_COL_SHIFT(pass);
+
+ for (xin=0; xout<w; xout+=xstep)
+ {
+ pixel_copy(buffer, xout, row, xin, pixel_size);
+ ++xin;
+ }
+}
+
+/* Build a single row for the 'size' test images; this fills in only the
+ * first bit_width bits of the sample row.
+ */
+static void
+size_row(png_byte buffer[SIZE_ROWMAX], png_uint_32 bit_width, png_uint_32 y)
+{
+ /* height is in the range 1 to 16, so: */
+ y = ((y & 1) << 7) + ((y & 2) << 6) + ((y & 4) << 5) + ((y & 8) << 4);
+ /* the following ensures bits are set in small images: */
+ y ^= 0xA5;
+
+ while (bit_width >= 8)
+ *buffer++ = (png_byte)y++, bit_width -= 8;
+
+ /* There may be up to 7 remaining bits, these go in the most significant
+ * bits of the byte.
+ */
+ if (bit_width > 0)
+ {
+ png_uint_32 mask = (1U<<(8-bit_width))-1;
+ *buffer = (png_byte)((*buffer & mask) | (y & ~mask));
+ }
+}
+
+static void
+make_size_image(png_store* PNG_CONST ps, png_byte PNG_CONST colour_type,
+ png_byte PNG_CONST bit_depth, int PNG_CONST interlace_type,
+ png_uint_32 PNG_CONST w, png_uint_32 PNG_CONST h,
+ int PNG_CONST do_interlace)
+{
+ context(ps, fault);
+
+ Try
+ {
+ png_infop pi;
+ png_structp pp;
+ unsigned int pixel_size;
+
+ /* Make a name and get an appropriate id for the store: */
+ char name[FILE_NAME_SIZE];
+ PNG_CONST png_uint_32 id = FILEID(colour_type, bit_depth, 0/*palette*/,
+ interlace_type, w, h, do_interlace);
+
+ standard_name_from_id(name, sizeof name, 0, id);
+ pp = set_store_for_write(ps, &pi, name);
+
+ /* In the event of a problem return control to the Catch statement below
+ * to do the clean up - it is not possible to 'return' directly from a Try
+ * block.
+ */
+ if (pp == NULL)
+ Throw ps;
+
+ png_set_IHDR(pp, pi, w, h, bit_depth, colour_type, interlace_type,
+ PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+
+ if (colour_type == 3) /* palette */
+ init_standard_palette(ps, pp, pi, 1U << bit_depth, 0/*do tRNS*/);
+
+ png_write_info(pp, pi);
+
+ /* Calculate the bit size, divide by 8 to get the byte size - this won't
+ * overflow because we know the w values are all small enough even for
+ * a system where 'unsigned int' is only 16 bits.
+ */
+ pixel_size = bit_size(pp, colour_type, bit_depth);
+ if (png_get_rowbytes(pp, pi) != ((w * pixel_size) + 7) / 8)
+ png_error(pp, "row size incorrect");
+
+ else
+ {
+ int npasses = npasses_from_interlace_type(pp, interlace_type);
+ png_uint_32 y;
+ int pass;
+ png_byte image[16][SIZE_ROWMAX];
+
+ /* To help consistent error detection make the parts of this buffer
+ * that aren't set below all '1':
+ */
+ memset(image, 0xff, sizeof image);
+
+ if (!do_interlace && npasses != png_set_interlace_handling(pp))
+ png_error(pp, "write: png_set_interlace_handling failed");
+
+ /* Prepare the whole image first to avoid making it 7 times: */
+ for (y=0; y<h; ++y)
+ size_row(image[y], w * pixel_size, y);
+
+ for (pass=0; pass<npasses; ++pass)
+ {
+ /* The following two are for checking the macros: */
+ PNG_CONST png_uint_32 wPass = PNG_PASS_COLS(w, pass);
+
+ /* If do_interlace is set we don't call png_write_row for every
+ * row because some of them are empty. In fact, for a 1x1 image,
+ * most of them are empty!
+ */
+ for (y=0; y<h; ++y)
+ {
+ png_const_bytep row = image[y];
+ png_byte tempRow[SIZE_ROWMAX];
+
+ /* If do_interlace *and* the image is interlaced we
+ * need a reduced interlace row; this may be reduced
+ * to empty.
+ */
+ if (do_interlace && interlace_type == PNG_INTERLACE_ADAM7)
+ {
+ /* The row must not be written if it doesn't exist, notice
+ * that there are two conditions here, either the row isn't
+ * ever in the pass or the row would be but isn't wide
+ * enough to contribute any pixels. In fact the wPass test
+ * can be used to skip the whole y loop in this case.
+ */
+ if (PNG_ROW_IN_INTERLACE_PASS(y, pass) && wPass > 0)
+ {
+ /* Set to all 1's for error detection (libpng tends to
+ * set unset things to 0).
+ */
+ memset(tempRow, 0xff, sizeof tempRow);
+ interlace_row(tempRow, row, pixel_size, w, pass);
+ row = tempRow;
+ }
+ else
+ continue;
+ }
+
+ /* Only get to here if the row has some pixels in it. */
+ png_write_row(pp, row);
+ }
+ }
+ }
+
+ png_write_end(pp, pi);
+
+ /* And store this under the appropriate id, then clean up. */
+ store_storefile(ps, id);
+
+ store_write_reset(ps);
+ }
+
+ Catch(fault)
+ {
+ /* Use the png_store returned by the exception. This may help the compiler
+ * because 'ps' is not used in this branch of the setjmp. Note that fault
+ * and ps will always be the same value.
+ */
+ store_write_reset(fault);
+ }
+}
+
+static void
+make_size(png_store* PNG_CONST ps, png_byte PNG_CONST colour_type, int bdlo,
+ int PNG_CONST bdhi)
+{
+ for (; bdlo <= bdhi; ++bdlo)
+ {
+ png_uint_32 width;
+
+ for (width = 1; width <= 16; ++width)
+ {
+ png_uint_32 height;
+
+ for (height = 1; height <= 16; ++height)
+ {
+ /* The four combinations of DIY interlace and interlace or not -
+ * no interlace + DIY should be identical to no interlace with
+ * libpng doing it.
+ */
+ make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_NONE,
+ width, height, 0);
+ make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_NONE,
+ width, height, 1);
+ make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_ADAM7,
+ width, height, 0);
+ make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_ADAM7,
+ width, height, 1);
+ }
+ }
+ }
+}
+
+static void
+make_size_images(png_store *ps)
+{
+ /* This is in case of errors. */
+ safecat(ps->test, sizeof ps->test, 0, "make size images");
+
+ /* Arguments are colour_type, low bit depth, high bit depth
+ */
+ make_size(ps, 0, 0, WRITE_BDHI);
+ make_size(ps, 2, 3, WRITE_BDHI);
+ make_size(ps, 3, 0, 3 /*palette: max 8 bits*/);
+ make_size(ps, 4, 3, WRITE_BDHI);
+ make_size(ps, 6, 3, WRITE_BDHI);
+}
+
+/* Return a row based on image id and 'y' for checking: */
+static void
+standard_row(png_structp pp, png_byte std[STANDARD_ROWMAX], png_uint_32 id,
+ png_uint_32 y)
+{
+ if (WIDTH_FROM_ID(id) == 0)
+ transform_row(pp, std, COL_FROM_ID(id), DEPTH_FROM_ID(id), y);
+ else
+ size_row(std, WIDTH_FROM_ID(id) * bit_size(pp, COL_FROM_ID(id),
+ DEPTH_FROM_ID(id)), y);
+}
+
+/* Tests - individual test cases */
+/* Like 'make_standard' but errors are deliberately introduced into the calls
+ * to ensure that they get detected - it should not be possible to write an
+ * invalid image with libpng!
+ */
+#ifdef PNG_WARNINGS_SUPPORTED
+static void
+sBIT0_error_fn(png_structp pp, png_infop pi)
+{
+ /* 0 is invalid... */
+ png_color_8 bad;
+ bad.red = bad.green = bad.blue = bad.gray = bad.alpha = 0;
+ png_set_sBIT(pp, pi, &bad);
+}
+
+static void
+sBIT_error_fn(png_structp pp, png_infop pi)
+{
+ png_byte bit_depth;
+ png_color_8 bad;
+
+ if (png_get_color_type(pp, pi) == PNG_COLOR_TYPE_PALETTE)
+ bit_depth = 8;
+
+ else
+ bit_depth = png_get_bit_depth(pp, pi);
+
+ /* Now we know the bit depth we can easily generate an invalid sBIT entry */
+ bad.red = bad.green = bad.blue = bad.gray = bad.alpha =
+ (png_byte)(bit_depth+1);
+ png_set_sBIT(pp, pi, &bad);
+}
+
+static PNG_CONST struct
+{
+ void (*fn)(png_structp, png_infop);
+ PNG_CONST char *msg;
+ unsigned int warning :1; /* the error is a warning... */
+} error_test[] =
+ {
+ /* no warnings makes these errors undetectable. */
+ { sBIT0_error_fn, "sBIT(0): failed to detect error", 1 },
+ { sBIT_error_fn, "sBIT(too big): failed to detect error", 1 },
+ };
+
+static void
+make_error(png_store* volatile psIn, png_byte PNG_CONST colour_type,
+ png_byte bit_depth, int interlace_type, int test, png_const_charp name)
+{
+ png_store * volatile ps = psIn;
+
+ context(ps, fault);
+
+ Try
+ {
+ png_structp pp;
+ png_infop pi;
+
+ pp = set_store_for_write(ps, &pi, name);
+
+ if (pp == NULL)
+ Throw ps;
+
+ png_set_IHDR(pp, pi, transform_width(pp, colour_type, bit_depth),
+ transform_height(pp, colour_type, bit_depth), bit_depth, colour_type,
+ interlace_type, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
+
+ if (colour_type == 3) /* palette */
+ init_standard_palette(ps, pp, pi, 1U << bit_depth, 0/*do tRNS*/);
+
+ /* Time for a few errors; these are in various optional chunks, the
+ * standard tests test the standard chunks pretty well.
+ */
+# define exception__prev exception_prev_1
+# define exception__env exception_env_1
+ Try
+ {
+ /* Expect this to throw: */
+ ps->expect_error = !error_test[test].warning;
+ ps->expect_warning = error_test[test].warning;
+ ps->saw_warning = 0;
+ error_test[test].fn(pp, pi);
+
+ /* Normally the error is only detected here: */
+ png_write_info(pp, pi);
+
+ /* And handle the case where it was only a warning: */
+ if (ps->expect_warning && ps->saw_warning)
+ Throw ps;
+
+ /* If we get here there is a problem, we have success - no error or
+ * no warning - when we shouldn't have success. Log an error.
+ */
+ store_log(ps, pp, error_test[test].msg, 1 /*error*/);
+ }
+
+ Catch (fault)
+ ps = fault; /* expected exit, make sure ps is not clobbered */
+#undef exception__prev
+#undef exception__env
+
+ /* And clear these flags */
+ ps->expect_error = 0;
+ ps->expect_warning = 0;
+
+ /* Now write the whole image, just to make sure that the detected, or
+ * undetected, errro has not created problems inside libpng.
+ */
+ if (png_get_rowbytes(pp, pi) !=
+ transform_rowsize(pp, colour_type, bit_depth))
+ png_error(pp, "row size incorrect");
+
+ else
+ {
+ png_uint_32 h = transform_height(pp, colour_type, bit_depth);
+ int npasses = png_set_interlace_handling(pp);
+ int pass;
+
+ if (npasses != npasses_from_interlace_type(pp, interlace_type))
+ png_error(pp, "write: png_set_interlace_handling failed");
+
+ for (pass=0; pass<npasses; ++pass)
+ {
+ png_uint_32 y;
+
+ for (y=0; y<h; ++y)
+ {
+ png_byte buffer[TRANSFORM_ROWMAX];
+
+ transform_row(pp, buffer, colour_type, bit_depth, y);
+ png_write_row(pp, buffer);
+ }
+ }
+ }
+
+ png_write_end(pp, pi);
+
+ /* The following deletes the file that was just written. */
+ store_write_reset(ps);
+ }
+
+ Catch(fault)
+ {
+ store_write_reset(fault);
+ }
+}
+
+static int
+make_errors(png_modifier* PNG_CONST pm, png_byte PNG_CONST colour_type,
+ int bdlo, int PNG_CONST bdhi)
+{
+ for (; bdlo <= bdhi; ++bdlo)
+ {
+ int interlace_type;
+
+ for (interlace_type = PNG_INTERLACE_NONE;
+ interlace_type < PNG_INTERLACE_LAST; ++interlace_type)
+ {
+ unsigned int test;
+ char name[FILE_NAME_SIZE];
+
+ standard_name(name, sizeof name, 0, colour_type, 1<<bdlo, 0,
+ interlace_type, 0, 0, 0);
+
+ for (test=0; test<(sizeof error_test)/(sizeof error_test[0]); ++test)
+ {
+ make_error(&pm->this, colour_type, DEPTH(bdlo), interlace_type,
+ test, name);
+
+ if (fail(pm))
+ return 0;
+ }
+ }
+ }
+
+ return 1; /* keep going */
+}
+#endif
+
+static void
+perform_error_test(png_modifier *pm)
+{
+#ifdef PNG_WARNINGS_SUPPORTED /* else there are no cases that work! */
+ /* Need to do this here because we just write in this test. */
+ safecat(pm->this.test, sizeof pm->this.test, 0, "error test");
+
+ if (!make_errors(pm, 0, 0, WRITE_BDHI))
+ return;
+
+ if (!make_errors(pm, 2, 3, WRITE_BDHI))
+ return;
+
+ if (!make_errors(pm, 3, 0, 3))
+ return;
+
+ if (!make_errors(pm, 4, 3, WRITE_BDHI))
+ return;
+
+ if (!make_errors(pm, 6, 3, WRITE_BDHI))
+ return;
+#else
+ UNUSED(pm)
+#endif
+}
+
+/* This is just to validate the internal PNG formatting code - if this fails
+ * then the warning messages the library outputs will probably be garbage.
+ */
+static void
+perform_formatting_test(png_store *volatile ps)
+{
+#ifdef PNG_TIME_RFC1123_SUPPORTED
+ /* The handle into the formatting code is the RFC1123 support; this test does
+ * nothing if that is compiled out.
+ */
+ context(ps, fault);
+
+ Try
+ {
+ png_const_charp correct = "29 Aug 2079 13:53:60 +0000";
+ png_const_charp result;
+ png_structp pp;
+ png_time pt;
+
+ pp = set_store_for_write(ps, NULL, "libpng formatting test");
+
+ if (pp == NULL)
+ Throw ps;
+
+
+ /* Arbitrary settings: */
+ pt.year = 2079;
+ pt.month = 8;
+ pt.day = 29;
+ pt.hour = 13;
+ pt.minute = 53;
+ pt.second = 60; /* a leap second */
+
+ result = png_convert_to_rfc1123(pp, &pt);
+
+ if (result == NULL)
+ png_error(pp, "png_convert_to_rfc1123 failed");
+
+ if (strcmp(result, correct) != 0)
+ {
+ size_t pos = 0;
+ char msg[128];
+
+ pos = safecat(msg, sizeof msg, pos, "png_convert_to_rfc1123(");
+ pos = safecat(msg, sizeof msg, pos, correct);
+ pos = safecat(msg, sizeof msg, pos, ") returned: '");
+ pos = safecat(msg, sizeof msg, pos, result);
+ pos = safecat(msg, sizeof msg, pos, "'");
+
+ png_error(pp, msg);
+ }
+
+ store_write_reset(ps);
+ }
+
+ Catch(fault)
+ {
+ store_write_reset(fault);
+ }
+#else
+ UNUSED(ps)
+#endif
+}
+
+/* Because we want to use the same code in both the progressive reader and the
+ * sequential reader it is necessary to deal with the fact that the progressive
+ * reader callbacks only have one parameter (png_get_progressive_ptr()), so this
+ * must contain all the test parameters and all the local variables directly
+ * accessible to the sequential reader implementation.
+ *
+ * The technique adopted is to reinvent part of what Dijkstra termed a
+ * 'display'; an array of pointers to the stack frames of enclosing functions so
+ * that a nested function definition can access the local (C auto) variables of
+ * the functions that contain its definition. In fact C provides the first
+ * pointer (the local variables - the stack frame pointer) and the last (the
+ * global variables - the BCPL global vector typically implemented as global
+ * addresses), this code requires one more pointer to make the display - the
+ * local variables (and function call parameters) of the function that actually
+ * invokes either the progressive or sequential reader.
+ *
+ * Perhaps confusingly this technique is confounded with classes - the
+ * 'standard_display' defined here is sub-classed as the 'gamma_display' below.
+ * A gamma_display is a standard_display, taking advantage of the ANSI-C
+ * requirement that the pointer to the first member of a structure must be the
+ * same as the pointer to the structure. This allows us to reuse standard_
+ * functions in the gamma test code; something that could not be done with
+ * nested functions!
+ */
+typedef struct standard_display
+{
+ png_store* ps; /* Test parameters (passed to the function) */
+ png_byte colour_type;
+ png_byte bit_depth;
+ png_byte red_sBIT; /* Input data sBIT values. */
+ png_byte green_sBIT;
+ png_byte blue_sBIT;
+ png_byte alpha_sBIT;
+ int interlace_type;
+ png_uint_32 id; /* Calculated file ID */
+ png_uint_32 w; /* Width of image */
+ png_uint_32 h; /* Height of image */
+ int npasses; /* Number of interlaced passes */
+ png_uint_32 pixel_size; /* Width of one pixel in bits */
+ png_uint_32 bit_width; /* Width of output row in bits */
+ size_t cbRow; /* Bytes in a row of the output image */
+ int do_interlace; /* Do interlacing internally */
+ int is_transparent; /* Transparency information was present. */
+ int speed; /* Doing a speed test */
+ int use_update_info;/* Call update_info, not start_image */
+ struct
+ {
+ png_uint_16 red;
+ png_uint_16 green;
+ png_uint_16 blue;
+ } transparent; /* The transparent color, if set. */
+ int npalette; /* Number of entries in the palette. */
+ store_palette
+ palette;
+} standard_display;
+
+static void
+standard_display_init(standard_display *dp, png_store* ps, png_uint_32 id,
+ int do_interlace, int use_update_info)
+{
+ memset(dp, 0, sizeof *dp);
+
+ dp->ps = ps;
+ dp->colour_type = COL_FROM_ID(id);
+ dp->bit_depth = DEPTH_FROM_ID(id);
+ if (dp->bit_depth < 1 || dp->bit_depth > 16)
+ internal_error(ps, "internal: bad bit depth");
+ if (dp->colour_type == 3)
+ dp->red_sBIT = dp->blue_sBIT = dp->green_sBIT = dp->alpha_sBIT = 8;
+ else
+ dp->red_sBIT = dp->blue_sBIT = dp->green_sBIT = dp->alpha_sBIT =
+ dp->bit_depth;
+ dp->interlace_type = INTERLACE_FROM_ID(id);
+ dp->id = id;
+ /* All the rest are filled in after the read_info: */
+ dp->w = 0;
+ dp->h = 0;
+ dp->npasses = 0;
+ dp->pixel_size = 0;
+ dp->bit_width = 0;
+ dp->cbRow = 0;
+ dp->do_interlace = do_interlace;
+ dp->is_transparent = 0;
+ dp->speed = ps->speed;
+ dp->use_update_info = use_update_info;
+ dp->npalette = 0;
+ /* Preset the transparent color to black: */
+ memset(&dp->transparent, 0, sizeof dp->transparent);
+ /* Preset the palette to full intensity/opaque througout: */
+ memset(dp->palette, 0xff, sizeof dp->palette);
+}
+
+/* Initialize the palette fields - this must be done later because the palette
+ * comes from the particular png_store_file that is selected.
+ */
+static void
+standard_palette_init(standard_display *dp)
+{
+ store_palette_entry *palette = store_current_palette(dp->ps, &dp->npalette);
+
+ /* The remaining entries remain white/opaque. */
+ if (dp->npalette > 0)
+ {
+ int i = dp->npalette;
+ memcpy(dp->palette, palette, i * sizeof *palette);
+
+ /* Check for a non-opaque palette entry: */
+ while (--i >= 0)
+ if (palette[i].alpha < 255)
+ break;
+
+# ifdef __GNUC__
+ /* GCC can't handle the more obviously optimizable version. */
+ if (i >= 0)
+ dp->is_transparent = 1;
+ else
+ dp->is_transparent = 0;
+# else
+ dp->is_transparent = (i >= 0);
+# endif
+ }
+}
+
+/* Utility to read the palette from the PNG file and convert it into
+ * store_palette format. This returns 1 if there is any transparency in the
+ * palette (it does not check for a transparent colour in the non-palette case.)
+ */
+static int
+read_palette(store_palette palette, int *npalette, png_structp pp, png_infop pi)
+{
+ png_colorp pal;
+ png_bytep trans_alpha;
+ int num;
+
+ pal = 0;
+ *npalette = -1;
+
+ if (png_get_PLTE(pp, pi, &pal, npalette) & PNG_INFO_PLTE)
+ {
+ int i = *npalette;
+
+ if (i <= 0 || i > 256)
+ png_error(pp, "validate: invalid PLTE count");
+
+ while (--i >= 0)
+ {
+ palette[i].red = pal[i].red;
+ palette[i].green = pal[i].green;
+ palette[i].blue = pal[i].blue;
+ }
+
+ /* Mark the remainder of the entries with a flag value (other than
+ * white/opaque which is the flag value stored above.)
+ */
+ memset(palette + *npalette, 126, (256-*npalette) * sizeof *palette);
+ }
+
+ else /* !png_get_PLTE */
+ {
+ if (*npalette != (-1))
+ png_error(pp, "validate: invalid PLTE result");
+ /* But there is no palette, so record this: */
+ *npalette = 0;
+ memset(palette, 113, sizeof (store_palette));
+ }
+
+ trans_alpha = 0;
+ num = 2; /* force error below */
+ if ((png_get_tRNS(pp, pi, &trans_alpha, &num, 0) & PNG_INFO_tRNS) != 0 &&
+ (trans_alpha != NULL || num != 1/*returns 1 for a transparent color*/) &&
+ /* Oops, if a palette tRNS gets expanded png_read_update_info (at least so
+ * far as 1.5.4) does not remove the trans_alpha pointer, only num_trans,
+ * so in the above call we get a success, we get a pointer (who knows what
+ * to) and we get num_trans == 0:
+ */
+ !(trans_alpha != NULL && num == 0)) /* TODO: fix this in libpng. */
+ {
+ int i;
+
+ /* Any of these are crash-worthy - given the implementation of
+ * png_get_tRNS up to 1.5 an app won't crash if it just checks the
+ * result above and fails to check that the variables it passed have
+ * actually been filled in! Note that if the app were to pass the
+ * last, png_color_16p, variable too it couldn't rely on this.
+ */
+ if (trans_alpha == NULL || num <= 0 || num > 256 || num > *npalette)
+ png_error(pp, "validate: unexpected png_get_tRNS (palette) result");
+
+ for (i=0; i<num; ++i)
+ palette[i].alpha = trans_alpha[i];
+
+ for (num=*npalette; i<num; ++i)
+ palette[i].alpha = 255;
+
+ for (; i<256; ++i)
+ palette[i].alpha = 33; /* flag value */
+
+ return 1; /* transparency */
+ }
+
+ else
+ {
+ /* No palette transparency - just set the alpha channel to opaque. */
+ int i;
+
+ for (i=0, num=*npalette; i<num; ++i)
+ palette[i].alpha = 255;
+
+ for (; i<256; ++i)
+ palette[i].alpha = 55; /* flag value */
+
+ return 0; /* no transparency */
+ }
+}
+
+/* Utility to validate the palette if it should not have changed (the
+ * non-transform case).
+ */
+static void
+standard_palette_validate(standard_display *dp, png_structp pp, png_infop pi)
+{
+ int npalette;
+ store_palette palette;
+
+ if (read_palette(palette, &npalette, pp, pi) != dp->is_transparent)
+ png_error(pp, "validate: palette transparency changed");
+
+ if (npalette != dp->npalette)
+ {
+ size_t pos = 0;
+ char msg[64];
+
+ pos = safecat(msg, sizeof msg, pos, "validate: palette size changed: ");
+ pos = safecatn(msg, sizeof msg, pos, dp->npalette);
+ pos = safecat(msg, sizeof msg, pos, " -> ");
+ pos = safecatn(msg, sizeof msg, pos, npalette);
+ png_error(pp, msg);
+ }
+
+ {
+ int i = npalette; /* npalette is aliased */
+
+ while (--i >= 0)
+ if (palette[i].red != dp->palette[i].red ||
+ palette[i].green != dp->palette[i].green ||
+ palette[i].blue != dp->palette[i].blue ||
+ palette[i].alpha != dp->palette[i].alpha)
+ png_error(pp, "validate: PLTE or tRNS chunk changed");
+ }
+}
+
+/* By passing a 'standard_display' the progressive callbacks can be used
+ * directly by the sequential code, the functions suffixed "_imp" are the
+ * implementations, the functions without the suffix are the callbacks.
+ *
+ * The code for the info callback is split into two because this callback calls
+ * png_read_update_info or png_start_read_image and what gets called depends on
+ * whether the info needs updating (we want to test both calls in pngvalid.)
+ */
+static void
+standard_info_part1(standard_display *dp, png_structp pp, png_infop pi)
+{
+ if (png_get_bit_depth(pp, pi) != dp->bit_depth)
+ png_error(pp, "validate: bit depth changed");
+
+ if (png_get_color_type(pp, pi) != dp->colour_type)
+ png_error(pp, "validate: color type changed");
+
+ if (png_get_filter_type(pp, pi) != PNG_FILTER_TYPE_BASE)
+ png_error(pp, "validate: filter type changed");
+
+ if (png_get_interlace_type(pp, pi) != dp->interlace_type)
+ png_error(pp, "validate: interlacing changed");
+
+ if (png_get_compression_type(pp, pi) != PNG_COMPRESSION_TYPE_BASE)
+ png_error(pp, "validate: compression type changed");
+
+ dp->w = png_get_image_width(pp, pi);
+
+ if (dp->w != standard_width(pp, dp->id))
+ png_error(pp, "validate: image width changed");
+
+ dp->h = png_get_image_height(pp, pi);
+
+ if (dp->h != standard_height(pp, dp->id))
+ png_error(pp, "validate: image height changed");
+
+ /* Record (but don't check at present) the input sBIT according to the colour
+ * type information.
+ */
+ {
+ png_color_8p sBIT = 0;
+
+ if (png_get_sBIT(pp, pi, &sBIT) & PNG_INFO_sBIT)
+ {
+ int sBIT_invalid = 0;
+
+ if (sBIT == 0)
+ png_error(pp, "validate: unexpected png_get_sBIT result");
+
+ if (dp->colour_type & PNG_COLOR_MASK_COLOR)
+ {
+ if (sBIT->red == 0 || sBIT->red > dp->bit_depth)
+ sBIT_invalid = 1;
+ else
+ dp->red_sBIT = sBIT->red;
+
+ if (sBIT->green == 0 || sBIT->green > dp->bit_depth)
+ sBIT_invalid = 1;
+ else
+ dp->green_sBIT = sBIT->green;
+
+ if (sBIT->blue == 0 || sBIT->blue > dp->bit_depth)
+ sBIT_invalid = 1;
+ else
+ dp->blue_sBIT = sBIT->blue;
+ }
+
+ else /* !COLOR */
+ {
+ if (sBIT->gray == 0 || sBIT->gray > dp->bit_depth)
+ sBIT_invalid = 1;
+ else
+ dp->blue_sBIT = dp->green_sBIT = dp->red_sBIT = sBIT->gray;
+ }
+
+ /* All 8 bits in tRNS for a palette image are significant - see the
+ * spec.
+ */
+ if (dp->colour_type & PNG_COLOR_MASK_ALPHA)
+ {
+ if (sBIT->alpha == 0 || sBIT->alpha > dp->bit_depth)
+ sBIT_invalid = 1;
+ else
+ dp->alpha_sBIT = sBIT->alpha;
+ }
+
+ if (sBIT_invalid)
+ png_error(pp, "validate: sBIT value out of range");
+ }
+ }
+
+ /* Important: this is validating the value *before* any transforms have been
+ * put in place. It doesn't matter for the standard tests, where there are
+ * no transforms, but it does for other tests where rowbytes may change after
+ * png_read_update_info.
+ */
+ if (png_get_rowbytes(pp, pi) != standard_rowsize(pp, dp->id))
+ png_error(pp, "validate: row size changed");
+
+ /* Validate the colour type 3 palette (this can be present on other color
+ * types.)
+ */
+ standard_palette_validate(dp, pp, pi);
+
+ /* In any case always check for a tranparent color (notice that the
+ * colour type 3 case must not give a successful return on the get_tRNS call
+ * with these arguments!)
+ */
+ {
+ png_color_16p trans_color = 0;
+
+ if (png_get_tRNS(pp, pi, 0, 0, &trans_color) & PNG_INFO_tRNS)
+ {
+ if (trans_color == 0)
+ png_error(pp, "validate: unexpected png_get_tRNS (color) result");
+
+ switch (dp->colour_type)
+ {
+ case 0:
+ dp->transparent.red = dp->transparent.green = dp->transparent.blue =
+ trans_color->gray;
+ dp->is_transparent = 1;
+ break;
+
+ case 2:
+ dp->transparent.red = trans_color->red;
+ dp->transparent.green = trans_color->green;
+ dp->transparent.blue = trans_color->blue;
+ dp->is_transparent = 1;
+ break;
+
+ case 3:
+ /* Not expected because it should result in the array case
+ * above.
+ */
+ png_error(pp, "validate: unexpected png_get_tRNS result");
+ break;
+
+ default:
+ png_error(pp, "validate: invalid tRNS chunk with alpha image");
+ }
+ }
+ }
+
+ /* Read the number of passes - expected to match the value used when
+ * creating the image (interlaced or not). This has the side effect of
+ * turning on interlace handling (if do_interlace is not set.)
+ */
+ dp->npasses = npasses_from_interlace_type(pp, dp->interlace_type);
+ if (!dp->do_interlace && dp->npasses != png_set_interlace_handling(pp))
+ png_error(pp, "validate: file changed interlace type");
+
+ /* Caller calls png_read_update_info or png_start_read_image now, then calls
+ * part2.
+ */
+}
+
+/* This must be called *after* the png_read_update_info call to get the correct
+ * 'rowbytes' value, otherwise png_get_rowbytes will refer to the untransformed
+ * image.
+ */
+static void
+standard_info_part2(standard_display *dp, png_structp pp, png_infop pi,
+ int nImages)
+{
+ /* Record cbRow now that it can be found. */
+ dp->pixel_size = bit_size(pp, png_get_color_type(pp, pi),
+ png_get_bit_depth(pp, pi));
+ dp->bit_width = png_get_image_width(pp, pi) * dp->pixel_size;
+ dp->cbRow = png_get_rowbytes(pp, pi);
+
+ /* Validate the rowbytes here again. */
+ if (dp->cbRow != (dp->bit_width+7)/8)
+ png_error(pp, "bad png_get_rowbytes calculation");
+
+ /* Then ensure there is enough space for the output image(s). */
+ store_ensure_image(dp->ps, pp, nImages, dp->cbRow, dp->h);
+}
+
+static void
+standard_info_imp(standard_display *dp, png_structp pp, png_infop pi,
+ int nImages)
+{
+ /* Note that the validation routine has the side effect of turning on
+ * interlace handling in the subsequent code.
+ */
+ standard_info_part1(dp, pp, pi);
+
+ /* And the info callback has to call this (or png_read_update_info - see
+ * below in the png_modifier code for that variant.
+ */
+ if (dp->use_update_info)
+ {
+ /* For debugging the effect of multiple calls: */
+ int i = dp->use_update_info;
+ while (i-- > 0)
+ png_read_update_info(pp, pi);
+ }
+
+ else
+ png_start_read_image(pp);
+
+ /* Validate the height, width and rowbytes plus ensure that sufficient buffer
+ * exists for decoding the image.
+ */
+ standard_info_part2(dp, pp, pi, nImages);
+}
+
+static void
+standard_info(png_structp pp, png_infop pi)
+{
+ standard_display *dp = voidcast(standard_display*,
+ png_get_progressive_ptr(pp));
+
+ /* Call with nImages==1 because the progressive reader can only produce one
+ * image.
+ */
+ standard_info_imp(dp, pp, pi, 1 /*only one image*/);
+}
+
+static void
+progressive_row(png_structp pp, png_bytep new_row, png_uint_32 y, int pass)
+{
+ PNG_CONST standard_display *dp = voidcast(standard_display*,
+ png_get_progressive_ptr(pp));
+
+ /* When handling interlacing some rows will be absent in each pass, the
+ * callback still gets called, but with a NULL pointer. This is checked
+ * in the 'else' clause below. We need our own 'cbRow', but we can't call
+ * png_get_rowbytes because we got no info structure.
+ */
+ if (new_row != NULL)
+ {
+ png_bytep row;
+
+ /* In the case where the reader doesn't do the interlace it gives
+ * us the y in the sub-image:
+ */
+ if (dp->do_interlace && dp->interlace_type == PNG_INTERLACE_ADAM7)
+ {
+#ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED
+ /* Use this opportunity to validate the png 'current' APIs: */
+ if (y != png_get_current_row_number(pp))
+ png_error(pp, "png_get_current_row_number is broken");
+
+ if (pass != png_get_current_pass_number(pp))
+ png_error(pp, "png_get_current_pass_number is broken");
+#endif
+
+ y = PNG_ROW_FROM_PASS_ROW(y, pass);
+ }
+
+ /* Validate this just in case. */
+ if (y >= dp->h)
+ png_error(pp, "invalid y to progressive row callback");
+
+ row = store_image_row(dp->ps, pp, 0, y);
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+ /* Combine the new row into the old: */
+ if (dp->do_interlace)
+ {
+ if (dp->interlace_type == PNG_INTERLACE_ADAM7)
+ deinterlace_row(row, new_row, dp->pixel_size, dp->w, pass);
+ else
+ row_copy(row, new_row, dp->pixel_size * dp->w);
+ }
+ else
+ png_progressive_combine_row(pp, row, new_row);
+ } else if (dp->interlace_type == PNG_INTERLACE_ADAM7 &&
+ PNG_ROW_IN_INTERLACE_PASS(y, pass) &&
+ PNG_PASS_COLS(dp->w, pass) > 0)
+ png_error(pp, "missing row in progressive de-interlacing");
+#endif /* PNG_READ_INTERLACING_SUPPORTED */
+}
+
+static void
+sequential_row(standard_display *dp, png_structp pp, png_infop pi,
+ PNG_CONST int iImage, PNG_CONST int iDisplay)
+{
+ PNG_CONST int npasses = dp->npasses;
+ PNG_CONST int do_interlace = dp->do_interlace &&
+ dp->interlace_type == PNG_INTERLACE_ADAM7;
+ PNG_CONST png_uint_32 height = standard_height(pp, dp->id);
+ PNG_CONST png_uint_32 width = standard_width(pp, dp->id);
+ PNG_CONST png_store* ps = dp->ps;
+ int pass;
+
+ for (pass=0; pass<npasses; ++pass)
+ {
+ png_uint_32 y;
+ png_uint_32 wPass = PNG_PASS_COLS(width, pass);
+
+ for (y=0; y<height; ++y)
+ {
+ if (do_interlace)
+ {
+ /* wPass may be zero or this row may not be in this pass.
+ * png_read_row must not be called in either case.
+ */
+ if (wPass > 0 && PNG_ROW_IN_INTERLACE_PASS(y, pass))
+ {
+ /* Read the row into a pair of temporary buffers, then do the
+ * merge here into the output rows.
+ */
+ png_byte row[STANDARD_ROWMAX], display[STANDARD_ROWMAX];
+
+ /* The following aids (to some extent) error detection - we can
+ * see where png_read_row wrote. Use opposite values in row and
+ * display to make this easier. Don't use 0xff (which is used in
+ * the image write code to fill unused bits) or 0 (which is a
+ * likely value to overwrite unused bits with).
+ */
+ memset(row, 0xc5, sizeof row);
+ memset(display, 0x5c, sizeof display);
+
+ png_read_row(pp, row, display);
+
+ if (iImage >= 0)
+ deinterlace_row(store_image_row(ps, pp, iImage, y), row,
+ dp->pixel_size, dp->w, pass);
+
+ if (iDisplay >= 0)
+ deinterlace_row(store_image_row(ps, pp, iDisplay, y), display,
+ dp->pixel_size, dp->w, pass);
+ }
+ }
+ else
+ png_read_row(pp,
+ iImage >= 0 ? store_image_row(ps, pp, iImage, y) : NULL,
+ iDisplay >= 0 ? store_image_row(ps, pp, iDisplay, y) : NULL);
+ }
+ }
+
+ /* And finish the read operation (only really necessary if the caller wants
+ * to find additional data in png_info from chunks after the last IDAT.)
+ */
+ png_read_end(pp, pi);
+}
+
+static void
+standard_row_validate(standard_display *dp, png_structp pp,
+ int iImage, int iDisplay, png_uint_32 y)
+{
+ int where;
+ png_byte std[STANDARD_ROWMAX];
+
+ /* The row must be pre-initialized to the magic number here for the size
+ * tests to pass:
+ */
+ memset(std, 178, sizeof std);
+ standard_row(pp, std, dp->id, y);
+
+ /* At the end both the 'row' and 'display' arrays should end up identical.
+ * In earlier passes 'row' will be partially filled in, with only the pixels
+ * that have been read so far, but 'display' will have those pixels
+ * replicated to fill the unread pixels while reading an interlaced image.
+#if PNG_LIBPNG_VER < 10506
+ * The side effect inside the libpng sequential reader is that the 'row'
+ * array retains the correct values for unwritten pixels within the row
+ * bytes, while the 'display' array gets bits off the end of the image (in
+ * the last byte) trashed. Unfortunately in the progressive reader the
+ * row bytes are always trashed, so we always do a pixel_cmp here even though
+ * a memcmp of all cbRow bytes will succeed for the sequential reader.
+#endif
+ */
+ if (iImage >= 0 &&
+ (where = pixel_cmp(std, store_image_row(dp->ps, pp, iImage, y),
+ dp->bit_width)) != 0)
+ {
+ char msg[64];
+ sprintf(msg, "PNG image row[%d][%d] changed from %.2x to %.2x", y,
+ where-1, std[where-1],
+ store_image_row(dp->ps, pp, iImage, y)[where-1]);
+ png_error(pp, msg);
+ }
+
+#if PNG_LIBPNG_VER < 10506
+ /* In this case use pixel_cmp because we need to compare a partial
+ * byte at the end of the row if the row is not an exact multiple
+ * of 8 bits wide. (This is fixed in libpng-1.5.6 and pixel_cmp is
+ * changed to match!)
+ */
+#endif
+ if (iDisplay >= 0 &&
+ (where = pixel_cmp(std, store_image_row(dp->ps, pp, iDisplay, y),
+ dp->bit_width)) != 0)
+ {
+ char msg[64];
+ sprintf(msg, "display row[%d][%d] changed from %.2x to %.2x", y,
+ where-1, std[where-1],
+ store_image_row(dp->ps, pp, iDisplay, y)[where-1]);
+ png_error(pp, msg);
+ }
+}
+
+static void
+standard_image_validate(standard_display *dp, png_structp pp, int iImage,
+ int iDisplay)
+{
+ png_uint_32 y;
+
+ if (iImage >= 0)
+ store_image_check(dp->ps, pp, iImage);
+
+ if (iDisplay >= 0)
+ store_image_check(dp->ps, pp, iDisplay);
+
+ for (y=0; y<dp->h; ++y)
+ standard_row_validate(dp, pp, iImage, iDisplay, y);
+
+ /* This avoids false positives if the validation code is never called! */
+ dp->ps->validated = 1;
+}
+
+static void
+standard_end(png_structp pp, png_infop pi)
+{
+ standard_display *dp = voidcast(standard_display*,
+ png_get_progressive_ptr(pp));
+
+ UNUSED(pi)
+
+ /* Validate the image - progressive reading only produces one variant for
+ * interlaced images.
+ */
+ standard_image_validate(dp, pp, 0, -1);
+}
+
+/* A single test run checking the standard image to ensure it is not damaged. */
+static void
+standard_test(png_store* PNG_CONST psIn, png_uint_32 PNG_CONST id,
+ int do_interlace, int use_update_info)
+{
+ standard_display d;
+ context(psIn, fault);
+
+ /* Set up the display (stack frame) variables from the arguments to the
+ * function and initialize the locals that are filled in later.
+ */
+ standard_display_init(&d, psIn, id, do_interlace, use_update_info);
+
+ /* Everything is protected by a Try/Catch. The functions called also
+ * typically have local Try/Catch blocks.
+ */
+ Try
+ {
+ png_structp pp;
+ png_infop pi;
+
+ /* Get a png_struct for reading the image. This will throw an error if it
+ * fails, so we don't need to check the result.
+ */
+ pp = set_store_for_read(d.ps, &pi, d.id,
+ d.do_interlace ? (d.ps->progressive ?
+ "pngvalid progressive deinterlacer" :
+ "pngvalid sequential deinterlacer") : (d.ps->progressive ?
+ "progressive reader" : "sequential reader"));
+
+ /* Initialize the palette correctly from the png_store_file. */
+ standard_palette_init(&d);
+
+ /* Introduce the correct read function. */
+ if (d.ps->progressive)
+ {
+ png_set_progressive_read_fn(pp, &d, standard_info, progressive_row,
+ standard_end);
+
+ /* Now feed data into the reader until we reach the end: */
+ store_progressive_read(d.ps, pp, pi);
+ }
+ else
+ {
+ /* Note that this takes the store, not the display. */
+ png_set_read_fn(pp, d.ps, store_read);
+
+ /* Check the header values: */
+ png_read_info(pp, pi);
+
+ /* The code tests both versions of the images that the sequential
+ * reader can produce.
+ */
+ standard_info_imp(&d, pp, pi, 2 /*images*/);
+
+ /* Need the total bytes in the image below; we can't get to this point
+ * unless the PNG file values have been checked against the expected
+ * values.
+ */
+ {
+ sequential_row(&d, pp, pi, 0, 1);
+
+ /* After the last pass loop over the rows again to check that the
+ * image is correct.
+ */
+ if (!d.speed)
+ standard_image_validate(&d, pp, 0, 1);
+ else
+ d.ps->validated = 1;
+ }
+ }
+
+ /* Check for validation. */
+ if (!d.ps->validated)
+ png_error(pp, "image read failed silently");
+
+ /* Successful completion. */
+ }
+
+ Catch(fault)
+ d.ps = fault; /* make sure this hasn't been clobbered. */
+
+ /* In either case clean up the store. */
+ store_read_reset(d.ps);
+}
+
+static int
+test_standard(png_modifier* PNG_CONST pm, png_byte PNG_CONST colour_type,
+ int bdlo, int PNG_CONST bdhi)
+{
+ for (; bdlo <= bdhi; ++bdlo)
+ {
+ int interlace_type;
+
+ for (interlace_type = PNG_INTERLACE_NONE;
+ interlace_type < PNG_INTERLACE_LAST; ++interlace_type)
+ {
+ standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
+ interlace_type, 0, 0, 0), 0/*do_interlace*/, pm->use_update_info);
+
+ if (fail(pm))
+ return 0;
+ }
+ }
+
+ return 1; /* keep going */
+}
+
+static void
+perform_standard_test(png_modifier *pm)
+{
+ /* Test each colour type over the valid range of bit depths (expressed as
+ * log2(bit_depth) in turn, stop as soon as any error is detected.
+ */
+ if (!test_standard(pm, 0, 0, READ_BDHI))
+ return;
+
+ if (!test_standard(pm, 2, 3, READ_BDHI))
+ return;
+
+ if (!test_standard(pm, 3, 0, 3))
+ return;
+
+ if (!test_standard(pm, 4, 3, READ_BDHI))
+ return;
+
+ if (!test_standard(pm, 6, 3, READ_BDHI))
+ return;
+}
+
+
+/********************************** SIZE TESTS ********************************/
+static int
+test_size(png_modifier* PNG_CONST pm, png_byte PNG_CONST colour_type,
+ int bdlo, int PNG_CONST bdhi)
+{
+ /* Run the tests on each combination.
+ *
+ * NOTE: on my 32 bit x86 each of the following blocks takes
+ * a total of 3.5 seconds if done across every combo of bit depth
+ * width and height. This is a waste of time in practice, hence the
+ * hinc and winc stuff:
+ */
+ static PNG_CONST png_byte hinc[] = {1, 3, 11, 1, 5};
+ static PNG_CONST png_byte winc[] = {1, 9, 5, 7, 1};
+ for (; bdlo <= bdhi; ++bdlo)
+ {
+ png_uint_32 h, w;
+
+ for (h=1; h<=16; h+=hinc[bdlo]) for (w=1; w<=16; w+=winc[bdlo])
+ {
+ /* First test all the 'size' images against the sequential
+ * reader using libpng to deinterlace (where required.) This
+ * validates the write side of libpng. There are four possibilities
+ * to validate.
+ */
+ standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
+ PNG_INTERLACE_NONE, w, h, 0), 0/*do_interlace*/,
+ pm->use_update_info);
+
+ if (fail(pm))
+ return 0;
+
+ standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
+ PNG_INTERLACE_NONE, w, h, 1), 0/*do_interlace*/,
+ pm->use_update_info);
+
+ if (fail(pm))
+ return 0;
+
+ standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
+ PNG_INTERLACE_ADAM7, w, h, 0), 0/*do_interlace*/,
+ pm->use_update_info);
+
+ if (fail(pm))
+ return 0;
+
+ standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
+ PNG_INTERLACE_ADAM7, w, h, 1), 0/*do_interlace*/,
+ pm->use_update_info);
+
+ if (fail(pm))
+ return 0;
+
+ /* Now validate the interlaced read side - do_interlace true,
+ * in the progressive case this does actually make a difference
+ * to the code used in the non-interlaced case too.
+ */
+ standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
+ PNG_INTERLACE_NONE, w, h, 0), 1/*do_interlace*/,
+ pm->use_update_info);
+
+ if (fail(pm))
+ return 0;
+
+ standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
+ PNG_INTERLACE_ADAM7, w, h, 0), 1/*do_interlace*/,
+ pm->use_update_info);
+
+ if (fail(pm))
+ return 0;
+ }
+ }
+
+ return 1; /* keep going */
+}
+
+static void
+perform_size_test(png_modifier *pm)
+{
+ /* Test each colour type over the valid range of bit depths (expressed as
+ * log2(bit_depth) in turn, stop as soon as any error is detected.
+ */
+ if (!test_size(pm, 0, 0, READ_BDHI))
+ return;
+
+ if (!test_size(pm, 2, 3, READ_BDHI))
+ return;
+
+ /* For the moment don't do the palette test - it's a waste of time when
+ * compared to the grayscale test.
+ */
+#if 0
+ if (!test_size(pm, 3, 0, 3))
+ return;
+#endif
+
+ if (!test_size(pm, 4, 3, READ_BDHI))
+ return;
+
+ if (!test_size(pm, 6, 3, READ_BDHI))
+ return;
+}
+
+
+/******************************* TRANSFORM TESTS ******************************/
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+/* A set of tests to validate libpng image transforms. The possibilities here
+ * are legion because the transforms can be combined in a combinatorial
+ * fashion. To deal with this some measure of restraint is required, otherwise
+ * the tests would take forever.
+ */
+typedef struct image_pixel
+{
+ /* A local (pngvalid) representation of a PNG pixel, in all its
+ * various forms.
+ */
+ unsigned int red, green, blue, alpha; /* For non-palette images. */
+ unsigned int palette_index; /* For a palette image. */
+ png_byte colour_type; /* As in the spec. */
+ png_byte bit_depth; /* Defines bit size in row */
+ png_byte sample_depth; /* Scale of samples */
+ int have_tRNS; /* tRNS chunk may need processing */
+
+ /* For checking the code calculates double precision floating point values
+ * along with an error value, accumulated from the transforms. Because an
+ * sBIT setting allows larger error bounds (indeed, by the spec, apparently
+ * up to just less than +/-1 in the scaled value) the *lowest* sBIT for each
+ * channel is stored. This sBIT value is folded in to the stored error value
+ * at the end of the application of the transforms to the pixel.
+ */
+ double redf, greenf, bluef, alphaf;
+ double rede, greene, bluee, alphae;
+ png_byte red_sBIT, green_sBIT, blue_sBIT, alpha_sBIT;
+} image_pixel;
+
+/* Shared utility function, see below. */
+static void
+image_pixel_setf(image_pixel *this, unsigned int max)
+{
+ this->redf = this->red / (double)max;
+ this->greenf = this->green / (double)max;
+ this->bluef = this->blue / (double)max;
+ this->alphaf = this->alpha / (double)max;
+
+ if (this->red < max)
+ this->rede = this->redf * DBL_EPSILON;
+ else
+ this->rede = 0;
+ if (this->green < max)
+ this->greene = this->greenf * DBL_EPSILON;
+ else
+ this->greene = 0;
+ if (this->blue < max)
+ this->bluee = this->bluef * DBL_EPSILON;
+ else
+ this->bluee = 0;
+ if (this->alpha < max)
+ this->alphae = this->alphaf * DBL_EPSILON;
+ else
+ this->alphae = 0;
+}
+
+/* Initialize the structure for the next pixel - call this before doing any
+ * transforms and call it for each pixel since all the fields may need to be
+ * reset.
+ */
+static void
+image_pixel_init(image_pixel *this, png_const_bytep row, png_byte colour_type,
+ png_byte bit_depth, png_uint_32 x, store_palette palette)
+{
+ PNG_CONST png_byte sample_depth = (png_byte)(colour_type ==
+ PNG_COLOR_TYPE_PALETTE ? 8 : bit_depth);
+ PNG_CONST unsigned int max = (1U<<sample_depth)-1;
+
+ /* Initially just set everything to the same number and the alpha to opaque.
+ * Note that this currently assumes a simple palette where entry x has colour
+ * rgb(x,x,x)!
+ */
+ this->palette_index = this->red = this->green = this->blue =
+ sample(row, colour_type, bit_depth, x, 0);
+ this->alpha = max;
+ this->red_sBIT = this->green_sBIT = this->blue_sBIT = this->alpha_sBIT =
+ sample_depth;
+
+ /* Then override as appropriate: */
+ if (colour_type == 3) /* palette */
+ {
+ /* This permits the caller to default to the sample value. */
+ if (palette != 0)
+ {
+ PNG_CONST unsigned int i = this->palette_index;
+
+ this->red = palette[i].red;
+ this->green = palette[i].green;
+ this->blue = palette[i].blue;
+ this->alpha = palette[i].alpha;
+ }
+ }
+
+ else /* not palette */
+ {
+ unsigned int i = 0;
+
+ if (colour_type & 2)
+ {
+ this->green = sample(row, colour_type, bit_depth, x, 1);
+ this->blue = sample(row, colour_type, bit_depth, x, 2);
+ i = 2;
+ }
+ if (colour_type & 4)
+ this->alpha = sample(row, colour_type, bit_depth, x, ++i);
+ }
+
+ /* Calculate the scaled values, these are simply the values divided by
+ * 'max' and the error is initialized to the double precision epsilon value
+ * from the header file.
+ */
+ image_pixel_setf(this, max);
+
+ /* Store the input information for use in the transforms - these will
+ * modify the information.
+ */
+ this->colour_type = colour_type;
+ this->bit_depth = bit_depth;
+ this->sample_depth = sample_depth;
+ this->have_tRNS = 0;
+}
+
+/* Convert a palette image to an rgb image. This necessarily converts the tRNS
+ * chunk at the same time, because the tRNS will be in palette form. The way
+ * palette validation works means that the original palette is never updated,
+ * instead the image_pixel value from the row contains the RGB of the
+ * corresponding palette entry and *this* is updated. Consequently this routine
+ * only needs to change the colour type information.
+ */
+static void
+image_pixel_convert_PLTE(image_pixel *this)
+{
+ if (this->colour_type == PNG_COLOR_TYPE_PALETTE)
+ {
+ if (this->have_tRNS)
+ {
+ this->colour_type = PNG_COLOR_TYPE_RGB_ALPHA;
+ this->have_tRNS = 0;
+ }
+ else
+ this->colour_type = PNG_COLOR_TYPE_RGB;
+
+ /* The bit depth of the row changes at this point too (notice that this is
+ * the row format, not the sample depth, which is separate.)
+ */
+ this->bit_depth = 8;
+ }
+}
+
+/* Add an alpha channel; this will import the tRNS information because tRNS is
+ * not valid in an alpha image. The bit depth will invariably be set to at
+ * least 8. Palette images will be converted to alpha (using the above API).
+ */
+static void
+image_pixel_add_alpha(image_pixel *this, PNG_CONST standard_display *display)
+{
+ if (this->colour_type == PNG_COLOR_TYPE_PALETTE)
+ image_pixel_convert_PLTE(this);
+
+ if ((this->colour_type & PNG_COLOR_MASK_ALPHA) == 0)
+ {
+ if (this->colour_type == PNG_COLOR_TYPE_GRAY)
+ {
+ if (this->bit_depth < 8)
+ this->bit_depth = 8;
+
+ if (this->have_tRNS)
+ {
+ this->have_tRNS = 0;
+
+ /* Check the input, original, channel value here against the
+ * original tRNS gray chunk valie.
+ */
+ if (this->red == display->transparent.red)
+ this->alphaf = 0;
+ else
+ this->alphaf = 1;
+ }
+ else
+ this->alphaf = 1;
+
+ this->colour_type = PNG_COLOR_TYPE_GRAY_ALPHA;
+ }
+
+ else if (this->colour_type == PNG_COLOR_TYPE_RGB)
+ {
+ if (this->have_tRNS)
+ {
+ this->have_tRNS = 0;
+
+ /* Again, check the exact input values, not the current transformed
+ * value!
+ */
+ if (this->red == display->transparent.red &&
+ this->green == display->transparent.green &&
+ this->blue == display->transparent.blue)
+ this->alphaf = 0;
+ else
+ this->alphaf = 1;
+
+ this->colour_type = PNG_COLOR_TYPE_RGB_ALPHA;
+ }
+ }
+
+ /* The error in the alpha is zero and the sBIT value comes from the
+ * original sBIT data (actually it will always be the original bit depth).
+ */
+ this->alphae = 0;
+ this->alpha_sBIT = display->alpha_sBIT;
+ }
+}
+
+struct transform_display;
+typedef struct image_transform
+{
+ /* The name of this transform: a string. */
+ PNG_CONST char *name;
+
+ /* Each transform can be disabled from the command line: */
+ int enable;
+
+ /* The global list of transforms; read only. */
+ struct image_transform *PNG_CONST list;
+
+ /* The global count of the number of times this transform has been set on an
+ * image.
+ */
+ unsigned int global_use;
+
+ /* The local count of the number of times this transform has been set. */
+ unsigned int local_use;
+
+ /* The next transform in the list, each transform must call its own next
+ * transform after it has processed the pixel successfully.
+ */
+ PNG_CONST struct image_transform *next;
+
+ /* A single transform for the image, expressed as a series of function
+ * callbacks and some space for values.
+ *
+ * First a callback to add any required modifications to the png_modifier;
+ * this gets called just before the modifier is set up for read.
+ */
+ void (*ini)(PNG_CONST struct image_transform *this,
+ struct transform_display *that);
+
+ /* And a callback to set the transform on the current png_read_struct:
+ */
+ void (*set)(PNG_CONST struct image_transform *this,
+ struct transform_display *that, png_structp pp, png_infop pi);
+
+ /* Then a transform that takes an input pixel in one PNG format or another
+ * and modifies it by a pngvalid implementation of the transform (thus
+ * duplicating the libpng intent without, we hope, duplicating the bugs
+ * in the libpng implementation!) The png_structp is solely to allow error
+ * reporting via png_error and png_warning.
+ */
+ void (*mod)(PNG_CONST struct image_transform *this, image_pixel *that,
+ png_structp pp, PNG_CONST struct transform_display *display);
+
+ /* Add this transform to the list and return true if the transform is
+ * meaningful for this colour type and bit depth - if false then the
+ * transform should have no effect on the image so there's not a lot of
+ * point running it.
+ */
+ int (*add)(struct image_transform *this,
+ PNG_CONST struct image_transform **that, png_byte colour_type,
+ png_byte bit_depth);
+} image_transform;
+
+typedef struct transform_display
+{
+ standard_display this;
+
+ /* Parameters */
+ png_modifier* pm;
+ PNG_CONST image_transform* transform_list;
+
+ /* Local variables */
+ png_byte output_colour_type;
+ png_byte output_bit_depth;
+
+ /* Modifications (not necessarily used.) */
+ gama_modification gama_mod;
+ chrm_modification chrm_mod;
+ srgb_modification srgb_mod;
+} transform_display;
+
+/* Set sRGB, cHRM and gAMA transforms as required by the current encoding. */
+static void
+transform_set_encoding(transform_display *this)
+{
+ /* Set up the png_modifier '_current' fields then use these to determine how
+ * to add appropriate chunks.
+ */
+ png_modifier *pm = this->pm;
+
+ modifier_set_encoding(pm);
+
+ if (modifier_color_encoding_is_set(pm))
+ {
+ if (modifier_color_encoding_is_sRGB(pm))
+ srgb_modification_init(&this->srgb_mod, pm, PNG_sRGB_INTENT_ABSOLUTE);
+
+ else
+ {
+ /* Set gAMA and cHRM separately. */
+ gama_modification_init(&this->gama_mod, pm, pm->current_gamma);
+
+ if (pm->current_encoding != 0)
+ chrm_modification_init(&this->chrm_mod, pm, pm->current_encoding);
+ }
+ }
+}
+
+/* Three functions to end the list: */
+static void
+image_transform_ini_end(PNG_CONST image_transform *this,
+ transform_display *that)
+{
+ UNUSED(this)
+ UNUSED(that)
+}
+
+static void
+image_transform_set_end(PNG_CONST image_transform *this,
+ transform_display *that, png_structp pp, png_infop pi)
+{
+ UNUSED(this)
+ UNUSED(that)
+ UNUSED(pp)
+ UNUSED(pi)
+}
+
+/* At the end of the list recalculate the output image pixel value from the
+ * double precision values set up by the preceding 'mod' calls:
+ */
+static unsigned int
+sample_scale(double sample_value, unsigned int scale)
+{
+ sample_value = floor(sample_value * scale + .5);
+
+ /* Return NaN as 0: */
+ if (!(sample_value > 0))
+ sample_value = 0;
+ else if (sample_value > scale)
+ sample_value = scale;
+
+ return (unsigned int)sample_value;
+}
+
+static void
+image_transform_mod_end(PNG_CONST image_transform *this, image_pixel *that,
+ png_structp pp, PNG_CONST transform_display *display)
+{
+ PNG_CONST unsigned int scale = (1U<<that->sample_depth)-1;
+
+ UNUSED(this)
+ UNUSED(pp)
+ UNUSED(display)
+
+ /* At the end recalculate the digitized red green and blue values according
+ * to the current sample_depth of the pixel.
+ *
+ * The sample value is simply scaled to the maximum, checking for over
+ * and underflow (which can both happen for some image transforms,
+ * including simple size scaling, though libpng doesn't do that at present.
+ */
+ that->red = sample_scale(that->redf, scale);
+
+ /* The error value is increased, at the end, according to the lowest sBIT
+ * value seen. Common sense tells us that the intermediate integer
+ * representations are no more accurate than +/- 0.5 in the integral values,
+ * the sBIT allows the implementation to be worse than this. In addition the
+ * PNG specification actually permits any error within the range (-1..+1),
+ * but that is ignored here. Instead the final digitized value is compared,
+ * below to the digitized value of the error limits - this has the net effect
+ * of allowing (almost) +/-1 in the output value. It's difficult to see how
+ * any algorithm that digitizes intermediate results can be more accurate.
+ */
+ that->rede += 1./(2*((1U<<that->red_sBIT)-1));
+
+ if (that->colour_type & PNG_COLOR_MASK_COLOR)
+ {
+ that->green = sample_scale(that->greenf, scale);
+ that->blue = sample_scale(that->bluef, scale);
+ that->greene += 1./(2*((1U<<that->green_sBIT)-1));
+ that->bluee += 1./(2*((1U<<that->blue_sBIT)-1));
+ }
+ else
+ {
+ that->blue = that->green = that->red;
+ that->bluef = that->greenf = that->redf;
+ that->bluee = that->greene = that->rede;
+ }
+
+ if ((that->colour_type & PNG_COLOR_MASK_ALPHA) ||
+ that->colour_type == PNG_COLOR_TYPE_PALETTE)
+ {
+ that->alpha = sample_scale(that->alphaf, scale);
+ that->alphae += 1./(2*((1U<<that->alpha_sBIT)-1));
+ }
+ else
+ {
+ that->alpha = scale; /* opaque */
+ that->alpha = 1; /* Override this. */
+ that->alphae = 0; /* It's exact ;-) */
+ }
+}
+
+/* Static 'end' structure: */
+static image_transform image_transform_end =
+{
+ "(end)", /* name */
+ 1, /* enable */
+ 0, /* list */
+ 0, /* global_use */
+ 0, /* local_use */
+ 0, /* next */
+ image_transform_ini_end,
+ image_transform_set_end,
+ image_transform_mod_end,
+ 0 /* never called, I want it to crash if it is! */
+};
+
+/* Reader callbacks and implementations, where they differ from the standard
+ * ones.
+ */
+static void
+transform_display_init(transform_display *dp, png_modifier *pm, png_uint_32 id,
+ PNG_CONST image_transform *transform_list)
+{
+ memset(dp, 0, sizeof *dp);
+
+ /* Standard fields */
+ standard_display_init(&dp->this, &pm->this, id, 0/*do_interlace*/,
+ pm->use_update_info);
+
+ /* Parameter fields */
+ dp->pm = pm;
+ dp->transform_list = transform_list;
+
+ /* Local variable fields */
+ dp->output_colour_type = 255; /* invalid */
+ dp->output_bit_depth = 255; /* invalid */
+}
+
+static void
+transform_info_imp(transform_display *dp, png_structp pp, png_infop pi)
+{
+ /* Reuse the standard stuff as appropriate. */
+ standard_info_part1(&dp->this, pp, pi);
+
+ /* Now set the list of transforms. */
+ dp->transform_list->set(dp->transform_list, dp, pp, pi);
+
+ /* Update the info structure for these transforms: */
+ {
+ int i = dp->this.use_update_info;
+ /* Always do one call, even if use_update_info is 0. */
+ do
+ png_read_update_info(pp, pi);
+ while (--i > 0);
+ }
+
+ /* And get the output information into the standard_display */
+ standard_info_part2(&dp->this, pp, pi, 1/*images*/);
+
+ /* Plus the extra stuff we need for the transform tests: */
+ dp->output_colour_type = png_get_color_type(pp, pi);
+ dp->output_bit_depth = png_get_bit_depth(pp, pi);
+
+ /* Validate the combination of colour type and bit depth that we are getting
+ * out of libpng; the semantics of something not in the PNG spec are, at
+ * best, unclear.
+ */
+ switch (dp->output_colour_type)
+ {
+ case PNG_COLOR_TYPE_PALETTE:
+ if (dp->output_bit_depth > 8) goto error;
+ /*FALL THROUGH*/
+ case PNG_COLOR_TYPE_GRAY:
+ if (dp->output_bit_depth == 1 || dp->output_bit_depth == 2 ||
+ dp->output_bit_depth == 4)
+ break;
+ /*FALL THROUGH*/
+ default:
+ if (dp->output_bit_depth == 8 || dp->output_bit_depth == 16)
+ break;
+ /*FALL THROUGH*/
+ error:
+ {
+ char message[128];
+ size_t pos;
+
+ pos = safecat(message, sizeof message, 0,
+ "invalid final bit depth: colour type(");
+ pos = safecatn(message, sizeof message, pos, dp->output_colour_type);
+ pos = safecat(message, sizeof message, pos, ") with bit depth: ");
+ pos = safecatn(message, sizeof message, pos, dp->output_bit_depth);
+
+ png_error(pp, message);
+ }
+ }
+
+ /* Use a test pixel to check that the output agrees with what we expect -
+ * this avoids running the whole test if the output is unexpected.
+ */
+ {
+ image_pixel test_pixel;
+
+ memset(&test_pixel, 0, sizeof test_pixel);
+ test_pixel.colour_type = dp->this.colour_type; /* input */
+ test_pixel.bit_depth = dp->this.bit_depth;
+ if (test_pixel.colour_type == PNG_COLOR_TYPE_PALETTE)
+ test_pixel.sample_depth = 8;
+ else
+ test_pixel.sample_depth = test_pixel.bit_depth;
+ /* Don't need sBIT here, but it must be set to non-zero to avoid
+ * arithmetic overflows.
+ */
+ test_pixel.have_tRNS = dp->this.is_transparent;
+ test_pixel.red_sBIT = test_pixel.green_sBIT = test_pixel.blue_sBIT =
+ test_pixel.alpha_sBIT = test_pixel.sample_depth;
+
+ dp->transform_list->mod(dp->transform_list, &test_pixel, pp, dp);
+
+ if (test_pixel.colour_type != dp->output_colour_type)
+ {
+ char message[128];
+ size_t pos = safecat(message, sizeof message, 0, "colour type ");
+
+ pos = safecatn(message, sizeof message, pos, dp->output_colour_type);
+ pos = safecat(message, sizeof message, pos, " expected ");
+ pos = safecatn(message, sizeof message, pos, test_pixel.colour_type);
+
+ png_error(pp, message);
+ }
+
+ if (test_pixel.bit_depth != dp->output_bit_depth)
+ {
+ char message[128];
+ size_t pos = safecat(message, sizeof message, 0, "bit depth ");
+
+ pos = safecatn(message, sizeof message, pos, dp->output_bit_depth);
+ pos = safecat(message, sizeof message, pos, " expected ");
+ pos = safecatn(message, sizeof message, pos, test_pixel.bit_depth);
+
+ png_error(pp, message);
+ }
+
+ /* If both bit depth and colour type are correct check the sample depth.
+ * I believe these are both internal errors.
+ */
+ if (test_pixel.colour_type == PNG_COLOR_TYPE_PALETTE)
+ {
+ if (test_pixel.sample_depth != 8) /* oops - internal error! */
+ png_error(pp, "pngvalid: internal: palette sample depth not 8");
+ }
+ else if (test_pixel.sample_depth != dp->output_bit_depth)
+ {
+ char message[128];
+ size_t pos = safecat(message, sizeof message, 0,
+ "internal: sample depth ");
+
+ pos = safecatn(message, sizeof message, pos, dp->output_bit_depth);
+ pos = safecat(message, sizeof message, pos, " expected ");
+ pos = safecatn(message, sizeof message, pos, test_pixel.sample_depth);
+
+ png_error(pp, message);
+ }
+ }
+}
+
+static void
+transform_info(png_structp pp, png_infop pi)
+{
+ transform_info_imp(voidcast(transform_display*, png_get_progressive_ptr(pp)),
+ pp, pi);
+}
+
+static void
+transform_range_check(png_structp pp, unsigned int r, unsigned int g,
+ unsigned int b, unsigned int a, unsigned int in_digitized, double in,
+ unsigned int out, png_byte sample_depth, double err, double limit,
+ PNG_CONST char *name, double digitization_error)
+{
+ /* Compare the scaled, digitzed, values of our local calculation (in+-err)
+ * with the digitized values libpng produced; 'sample_depth' is the actual
+ * digitization depth of the libpng output colors (the bit depth except for
+ * palette images where it is always 8.) The check on 'err' is to detect
+ * internal errors in pngvalid itself.
+ */
+ unsigned int max = (1U<<sample_depth)-1;
+ double in_min = ceil((in-err)*max - digitization_error);
+ double in_max = floor((in+err)*max + digitization_error);
+ if (err > limit || !(out >= in_min && out <= in_max))
+ {
+ char message[256];
+ size_t pos;
+
+ pos = safecat(message, sizeof message, 0, name);
+ pos = safecat(message, sizeof message, pos, " output value error: rgba(");
+ pos = safecatn(message, sizeof message, pos, r);
+ pos = safecat(message, sizeof message, pos, ",");
+ pos = safecatn(message, sizeof message, pos, g);
+ pos = safecat(message, sizeof message, pos, ",");
+ pos = safecatn(message, sizeof message, pos, b);
+ pos = safecat(message, sizeof message, pos, ",");
+ pos = safecatn(message, sizeof message, pos, a);
+ pos = safecat(message, sizeof message, pos, "): ");
+ pos = safecatn(message, sizeof message, pos, out);
+ pos = safecat(message, sizeof message, pos, " expected: ");
+ pos = safecatn(message, sizeof message, pos, in_digitized);
+ pos = safecat(message, sizeof message, pos, " (");
+ pos = safecatd(message, sizeof message, pos, (in-err)*max, 3);
+ pos = safecat(message, sizeof message, pos, "..");
+ pos = safecatd(message, sizeof message, pos, (in+err)*max, 3);
+ pos = safecat(message, sizeof message, pos, ")");
+
+ png_error(pp, message);
+ }
+}
+
+static void
+transform_image_validate(transform_display *dp, png_structp pp, png_infop pi)
+{
+ /* Constants for the loop below: */
+ PNG_CONST png_store* PNG_CONST ps = dp->this.ps;
+ PNG_CONST png_byte in_ct = dp->this.colour_type;
+ PNG_CONST png_byte in_bd = dp->this.bit_depth;
+ PNG_CONST png_uint_32 w = dp->this.w;
+ PNG_CONST png_uint_32 h = dp->this.h;
+ PNG_CONST png_byte out_ct = dp->output_colour_type;
+ PNG_CONST png_byte out_bd = dp->output_bit_depth;
+ PNG_CONST png_byte sample_depth = (png_byte)(out_ct ==
+ PNG_COLOR_TYPE_PALETTE ? 8 : out_bd);
+ PNG_CONST png_byte red_sBIT = dp->this.red_sBIT;
+ PNG_CONST png_byte green_sBIT = dp->this.green_sBIT;
+ PNG_CONST png_byte blue_sBIT = dp->this.blue_sBIT;
+ PNG_CONST png_byte alpha_sBIT = dp->this.alpha_sBIT;
+ PNG_CONST int have_tRNS = dp->this.is_transparent;
+ double digitization_error;
+
+ store_palette out_palette;
+ png_uint_32 y;
+
+ UNUSED(pi)
+
+ /* Check for row overwrite errors */
+ store_image_check(dp->this.ps, pp, 0);
+
+ /* Read the palette corresponding to the output if the output colour type
+ * indicates a palette, othewise set out_palette to garbage.
+ */
+ if (out_ct == PNG_COLOR_TYPE_PALETTE)
+ {
+ /* Validate that the palette count itself has not changed - this is not
+ * expected.
+ */
+ int npalette = (-1);
+
+ (void)read_palette(out_palette, &npalette, pp, pi);
+ if (npalette != dp->this.npalette)
+ png_error(pp, "unexpected change in palette size");
+
+ digitization_error = .5;
+ }
+ else
+ {
+ png_byte in_sample_depth;
+
+ memset(out_palette, 0x5e, sizeof out_palette);
+
+ /* assume-8-bit-calculations means assume that if the input has 8 bit
+ * (or less) samples and the output has 16 bit samples the calculations
+ * will be done with 8 bit precision, not 16.
+ *
+ * TODO: fix this in libpng; png_set_expand_16 should cause 16 bit
+ * calculations to be used throughout.
+ */
+ if (in_ct == PNG_COLOR_TYPE_PALETTE || in_bd < 16)
+ in_sample_depth = 8;
+ else
+ in_sample_depth = in_bd;
+
+ if (sample_depth != 16 || in_sample_depth > 8 ||
+ !dp->pm->calculations_use_input_precision)
+ digitization_error = .5;
+
+ /* Else errors are at 8 bit precision, scale .5 in 8 bits to the 16 bits:
+ */
+ else
+ digitization_error = .5 * 257;
+ }
+
+ for (y=0; y<h; ++y)
+ {
+ png_const_bytep PNG_CONST pRow = store_image_row(ps, pp, 0, y);
+ png_uint_32 x;
+
+ /* The original, standard, row pre-transforms. */
+ png_byte std[STANDARD_ROWMAX];
+
+ transform_row(pp, std, in_ct, in_bd, y);
+
+ /* Go through each original pixel transforming it and comparing with what
+ * libpng did to the same pixel.
+ */
+ for (x=0; x<w; ++x)
+ {
+ image_pixel in_pixel, out_pixel;
+ unsigned int r, g, b, a;
+
+ /* Find out what we think the pixel should be: */
+ image_pixel_init(&in_pixel, std, in_ct, in_bd, x, dp->this.palette);
+
+ in_pixel.red_sBIT = red_sBIT;
+ in_pixel.green_sBIT = green_sBIT;
+ in_pixel.blue_sBIT = blue_sBIT;
+ in_pixel.alpha_sBIT = alpha_sBIT;
+ in_pixel.have_tRNS = have_tRNS;
+
+ /* For error detection, below. */
+ r = in_pixel.red;
+ g = in_pixel.green;
+ b = in_pixel.blue;
+ a = in_pixel.alpha;
+
+ dp->transform_list->mod(dp->transform_list, &in_pixel, pp, dp);
+
+ /* Read the output pixel and compare it to what we got, we don't
+ * use the error field here, so no need to update sBIT.
+ */
+ image_pixel_init(&out_pixel, pRow, out_ct, out_bd, x, out_palette);
+
+ /* We don't expect changes to the index here even if the bit depth is
+ * changed.
+ */
+ if (in_ct == PNG_COLOR_TYPE_PALETTE &&
+ out_ct == PNG_COLOR_TYPE_PALETTE)
+ {
+ if (in_pixel.palette_index != out_pixel.palette_index)
+ png_error(pp, "unexpected transformed palette index");
+ }
+
+ /* Check the colours for palette images too - in fact the palette could
+ * be separately verified itself in most cases.
+ */
+ if (in_pixel.red != out_pixel.red)
+ transform_range_check(pp, r, g, b, a, in_pixel.red, in_pixel.redf,
+ out_pixel.red, sample_depth, in_pixel.rede,
+ dp->pm->limit + 1./(2*((1U<<in_pixel.red_sBIT)-1)), "red/gray",
+ digitization_error);
+
+ if ((out_ct & PNG_COLOR_MASK_COLOR) != 0 &&
+ in_pixel.green != out_pixel.green)
+ transform_range_check(pp, r, g, b, a, in_pixel.green,
+ in_pixel.greenf, out_pixel.green, sample_depth, in_pixel.greene,
+ dp->pm->limit + 1./(2*((1U<<in_pixel.green_sBIT)-1)), "green",
+ digitization_error);
+
+ if ((out_ct & PNG_COLOR_MASK_COLOR) != 0 &&
+ in_pixel.blue != out_pixel.blue)
+ transform_range_check(pp, r, g, b, a, in_pixel.blue, in_pixel.bluef,
+ out_pixel.blue, sample_depth, in_pixel.bluee,
+ dp->pm->limit + 1./(2*((1U<<in_pixel.blue_sBIT)-1)), "blue",
+ digitization_error);
+
+ if ((out_ct & PNG_COLOR_MASK_ALPHA) != 0 &&
+ in_pixel.alpha != out_pixel.alpha)
+ transform_range_check(pp, r, g, b, a, in_pixel.alpha,
+ in_pixel.alphaf, out_pixel.alpha, sample_depth, in_pixel.alphae,
+ dp->pm->limit + 1./(2*((1U<<in_pixel.alpha_sBIT)-1)), "alpha",
+ digitization_error);
+ } /* pixel (x) loop */
+ } /* row (y) loop */
+
+ /* Record that something was actually checked to avoid a false positive. */
+ dp->this.ps->validated = 1;
+}
+
+static void
+transform_end(png_structp pp, png_infop pi)
+{
+ transform_display *dp = voidcast(transform_display*,
+ png_get_progressive_ptr(pp));
+
+ if (!dp->this.speed)
+ transform_image_validate(dp, pp, pi);
+ else
+ dp->this.ps->validated = 1;
+}
+
+/* A single test run. */
+static void
+transform_test(png_modifier *pmIn, PNG_CONST png_uint_32 idIn,
+ PNG_CONST image_transform* transform_listIn, PNG_CONST char * volatile name)
+{
+ transform_display d;
+ context(&pmIn->this, fault);
+
+ transform_display_init(&d, pmIn, idIn, transform_listIn);
+
+ Try
+ {
+ size_t pos = 0;
+ png_structp pp;
+ png_infop pi;
+ char full_name[256];
+
+ /* Make sure the encoding fields are correct and enter the required
+ * modifications.
+ */
+ transform_set_encoding(&d);
+
+ /* Add any modifications required by the transform list. */
+ d.transform_list->ini(d.transform_list, &d);
+
+ /* Add the color space information, if any, to the name. */
+ pos = safecat(full_name, sizeof full_name, pos, name);
+ pos = safecat_current_encoding(full_name, sizeof full_name, pos, d.pm);
+
+ /* Get a png_struct for reading the image. */
+ pp = set_modifier_for_read(d.pm, &pi, d.this.id, full_name);
+ standard_palette_init(&d.this);
+
+# if 0
+ /* Logging (debugging only) */
+ {
+ char buffer[256];
+
+ (void)store_message(&d.pm->this, pp, buffer, sizeof buffer, 0,
+ "running test");
+
+ fprintf(stderr, "%s\n", buffer);
+ }
+# endif
+
+ /* Introduce the correct read function. */
+ if (d.pm->this.progressive)
+ {
+ /* Share the row function with the standard implementation. */
+ png_set_progressive_read_fn(pp, &d, transform_info, progressive_row,
+ transform_end);
+
+ /* Now feed data into the reader until we reach the end: */
+ modifier_progressive_read(d.pm, pp, pi);
+ }
+ else
+ {
+ /* modifier_read expects a png_modifier* */
+ png_set_read_fn(pp, d.pm, modifier_read);
+
+ /* Check the header values: */
+ png_read_info(pp, pi);
+
+ /* Process the 'info' requirements. Only one image is generated */
+ transform_info_imp(&d, pp, pi);
+
+ sequential_row(&d.this, pp, pi, -1, 0);
+
+ if (!d.this.speed)
+ transform_image_validate(&d, pp, pi);
+ else
+ d.this.ps->validated = 1;
+ }
+
+ modifier_reset(d.pm);
+ }
+
+ Catch(fault)
+ {
+ modifier_reset((png_modifier*)fault);
+ }
+}
+
+/* The transforms: */
+#define ITSTRUCT(name) image_transform_##name
+#define ITDATA(name) image_transform_data_##name
+#define image_transform_ini image_transform_default_ini
+#define IT(name)\
+static image_transform ITSTRUCT(name) =\
+{\
+ #name,\
+ 1, /*enable*/\
+ &PT, /*list*/\
+ 0, /*global_use*/\
+ 0, /*local_use*/\
+ 0, /*next*/\
+ image_transform_ini,\
+ image_transform_png_set_##name##_set,\
+ image_transform_png_set_##name##_mod,\
+ image_transform_png_set_##name##_add\
+}
+#define PT ITSTRUCT(end) /* stores the previous transform */
+
+/* To save code: */
+static void
+image_transform_default_ini(PNG_CONST image_transform *this,
+ transform_display *that)
+{
+ this->next->ini(this->next, that);
+}
+
+static int
+image_transform_default_add(image_transform *this,
+ PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+ UNUSED(colour_type)
+ UNUSED(bit_depth)
+
+ this->next = *that;
+ *that = this;
+
+ return 1;
+}
+
+#ifdef PNG_READ_EXPAND_SUPPORTED
+/* png_set_palette_to_rgb */
+static void
+image_transform_png_set_palette_to_rgb_set(PNG_CONST image_transform *this,
+ transform_display *that, png_structp pp, png_infop pi)
+{
+ png_set_palette_to_rgb(pp);
+ this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_palette_to_rgb_mod(PNG_CONST image_transform *this,
+ image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
+{
+ if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
+ image_pixel_convert_PLTE(that);
+
+ this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_palette_to_rgb_add(image_transform *this,
+ PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+ UNUSED(bit_depth)
+
+ this->next = *that;
+ *that = this;
+
+ return colour_type == PNG_COLOR_TYPE_PALETTE;
+}
+
+IT(palette_to_rgb);
+#undef PT
+#define PT ITSTRUCT(palette_to_rgb)
+#endif /* PNG_READ_EXPAND_SUPPORTED */
+
+#ifdef PNG_READ_EXPAND_SUPPORTED
+/* png_set_tRNS_to_alpha */
+static void
+image_transform_png_set_tRNS_to_alpha_set(PNG_CONST image_transform *this,
+ transform_display *that, png_structp pp, png_infop pi)
+{
+ png_set_tRNS_to_alpha(pp);
+ this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_tRNS_to_alpha_mod(PNG_CONST image_transform *this,
+ image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
+{
+ /* LIBPNG BUG: this always forces palette images to RGB. */
+ if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
+ image_pixel_convert_PLTE(that);
+
+ /* This effectively does an 'expand' only if there is some transparency to
+ * convert to an alpha channel.
+ */
+ if (that->have_tRNS)
+ image_pixel_add_alpha(that, &display->this);
+
+ /* LIBPNG BUG: otherwise libpng still expands to 8 bits! */
+ else
+ {
+ if (that->bit_depth < 8)
+ that->bit_depth =8;
+ if (that->sample_depth < 8)
+ that->sample_depth = 8;
+ }
+
+ this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_tRNS_to_alpha_add(image_transform *this,
+ PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+ UNUSED(bit_depth)
+
+ this->next = *that;
+ *that = this;
+
+ /* We don't know yet whether there will be a tRNS chunk, but we know that
+ * this transformation should do nothing if there already is an alpha
+ * channel.
+ */
+ return (colour_type & PNG_COLOR_MASK_ALPHA) == 0;
+}
+
+IT(tRNS_to_alpha);
+#undef PT
+#define PT ITSTRUCT(tRNS_to_alpha)
+#endif /* PNG_READ_EXPAND_SUPPORTED */
+
+#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
+/* png_set_gray_to_rgb */
+static void
+image_transform_png_set_gray_to_rgb_set(PNG_CONST image_transform *this,
+ transform_display *that, png_structp pp, png_infop pi)
+{
+ png_set_gray_to_rgb(pp);
+ this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_gray_to_rgb_mod(PNG_CONST image_transform *this,
+ image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
+{
+ /* NOTE: we can actually pend the tRNS processing at this point because we
+ * can correctly recognize the original pixel value even though we have
+ * mapped the one gray channel to the three RGB ones, but in fact libpng
+ * doesn't do this, so we don't either.
+ */
+ if ((that->colour_type & PNG_COLOR_MASK_COLOR) == 0 && that->have_tRNS)
+ image_pixel_add_alpha(that, &display->this);
+
+ /* Simply expand the bit depth and alter the colour type as required. */
+ if (that->colour_type == PNG_COLOR_TYPE_GRAY)
+ {
+ /* RGB images have a bit depth at least equal to '8' */
+ if (that->bit_depth < 8)
+ that->sample_depth = that->bit_depth = 8;
+
+ /* And just changing the colour type works here because the green and blue
+ * channels are being maintained in lock-step with the red/gray:
+ */
+ that->colour_type = PNG_COLOR_TYPE_RGB;
+ }
+
+ else if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+ that->colour_type = PNG_COLOR_TYPE_RGB_ALPHA;
+
+ this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_gray_to_rgb_add(image_transform *this,
+ PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+ UNUSED(bit_depth)
+
+ this->next = *that;
+ *that = this;
+
+ return (colour_type & PNG_COLOR_MASK_COLOR) == 0;
+}
+
+IT(gray_to_rgb);
+#undef PT
+#define PT ITSTRUCT(gray_to_rgb)
+#endif /* PNG_READ_GRAY_TO_RGB_SUPPORTED */
+
+#ifdef PNG_READ_EXPAND_SUPPORTED
+/* png_set_expand */
+static void
+image_transform_png_set_expand_set(PNG_CONST image_transform *this,
+ transform_display *that, png_structp pp, png_infop pi)
+{
+ png_set_expand(pp);
+ this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_expand_mod(PNG_CONST image_transform *this,
+ image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
+{
+ /* The general expand case depends on what the colour type is: */
+ if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
+ image_pixel_convert_PLTE(that);
+ else if (that->bit_depth < 8) /* grayscale */
+ that->sample_depth = that->bit_depth = 8;
+
+ if (that->have_tRNS)
+ image_pixel_add_alpha(that, &display->this);
+
+ this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_expand_add(image_transform *this,
+ PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+ UNUSED(bit_depth)
+
+ this->next = *that;
+ *that = this;
+
+ /* 'expand' should do nothing for RGBA or GA input - no tRNS and the bit
+ * depth is at least 8 already.
+ */
+ return (colour_type & PNG_COLOR_MASK_ALPHA) == 0;
+}
+
+IT(expand);
+#undef PT
+#define PT ITSTRUCT(expand)
+#endif /* PNG_READ_EXPAND_SUPPORTED */
+
+#ifdef PNG_READ_EXPAND_SUPPORTED
+/* png_set_expand_gray_1_2_4_to_8
+ * LIBPNG BUG: this just does an 'expand'
+ */
+static void
+image_transform_png_set_expand_gray_1_2_4_to_8_set(
+ PNG_CONST image_transform *this, transform_display *that, png_structp pp,
+ png_infop pi)
+{
+ png_set_expand_gray_1_2_4_to_8(pp);
+ this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_expand_gray_1_2_4_to_8_mod(
+ PNG_CONST image_transform *this, image_pixel *that, png_structp pp,
+ PNG_CONST transform_display *display)
+{
+ image_transform_png_set_expand_mod(this, that, pp, display);
+}
+
+static int
+image_transform_png_set_expand_gray_1_2_4_to_8_add(image_transform *this,
+ PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+ return image_transform_png_set_expand_add(this, that, colour_type,
+ bit_depth);
+}
+
+IT(expand_gray_1_2_4_to_8);
+#undef PT
+#define PT ITSTRUCT(expand_gray_1_2_4_to_8)
+#endif /* PNG_READ_EXPAND_SUPPORTED */
+
+#ifdef PNG_READ_EXPAND_16_SUPPORTED
+/* png_set_expand_16 */
+static void
+image_transform_png_set_expand_16_set(PNG_CONST image_transform *this,
+ transform_display *that, png_structp pp, png_infop pi)
+{
+ png_set_expand_16(pp);
+ this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_expand_16_mod(PNG_CONST image_transform *this,
+ image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
+{
+ /* Expect expand_16 to expand everything to 16 bits as a result of also
+ * causing 'expand' to happen.
+ */
+ if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
+ image_pixel_convert_PLTE(that);
+
+ if (that->have_tRNS)
+ image_pixel_add_alpha(that, &display->this);
+
+ if (that->bit_depth < 16)
+ that->sample_depth = that->bit_depth = 16;
+
+ this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_expand_16_add(image_transform *this,
+ PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+ UNUSED(colour_type)
+
+ this->next = *that;
+ *that = this;
+
+ /* expand_16 does something unless the bit depth is already 16. */
+ return bit_depth < 16;
+}
+
+IT(expand_16);
+#undef PT
+#define PT ITSTRUCT(expand_16)
+#endif /* PNG_READ_EXPAND_16_SUPPORTED */
+
+#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED /* API added in 1.5.4 */
+/* png_set_scale_16 */
+static void
+image_transform_png_set_scale_16_set(PNG_CONST image_transform *this,
+ transform_display *that, png_structp pp, png_infop pi)
+{
+ png_set_scale_16(pp);
+ this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_scale_16_mod(PNG_CONST image_transform *this,
+ image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
+{
+ if (that->bit_depth == 16)
+ {
+ that->sample_depth = that->bit_depth = 8;
+ if (that->red_sBIT > 8) that->red_sBIT = 8;
+ if (that->green_sBIT > 8) that->green_sBIT = 8;
+ if (that->blue_sBIT > 8) that->blue_sBIT = 8;
+ if (that->alpha_sBIT > 8) that->alpha_sBIT = 8;
+ }
+
+ this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_scale_16_add(image_transform *this,
+ PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+ UNUSED(colour_type)
+
+ this->next = *that;
+ *that = this;
+
+ return bit_depth > 8;
+}
+
+IT(scale_16);
+#undef PT
+#define PT ITSTRUCT(scale_16)
+#endif /* PNG_READ_SCALE_16_TO_8_SUPPORTED (1.5.4 on) */
+
+#ifdef PNG_READ_16_TO_8_SUPPORTED /* the default before 1.5.4 */
+/* png_set_strip_16 */
+static void
+image_transform_png_set_strip_16_set(PNG_CONST image_transform *this,
+ transform_display *that, png_structp pp, png_infop pi)
+{
+ png_set_strip_16(pp);
+ this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_strip_16_mod(PNG_CONST image_transform *this,
+ image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
+{
+ if (that->bit_depth == 16)
+ {
+ that->sample_depth = that->bit_depth = 8;
+ if (that->red_sBIT > 8) that->red_sBIT = 8;
+ if (that->green_sBIT > 8) that->green_sBIT = 8;
+ if (that->blue_sBIT > 8) that->blue_sBIT = 8;
+ if (that->alpha_sBIT > 8) that->alpha_sBIT = 8;
+
+ /* Prior to 1.5.4 png_set_strip_16 would use an 'accurate' method if this
+ * configuration option is set. From 1.5.4 the flag is never set and the
+ * 'scale' API (above) must be used.
+ */
+# ifdef PNG_READ_ACCURATE_SCALE_SUPPORTED
+# if PNG_LIBPNG_VER >= 10504
+# error PNG_READ_ACCURATE_SCALE should not be set
+# endif
+
+ /* The strip 16 algorithm drops the low 8 bits rather than calculating
+ * 1/257, so we need to adjust the permitted errors appropriately:
+ * Notice that this is only relevant prior to the addition of the
+ * png_set_scale_16 API in 1.5.4 (but 1.5.4+ always defines the above!)
+ */
+ {
+ PNG_CONST double d = (255-128.5)/65535;
+ that->rede += d;
+ that->greene += d;
+ that->bluee += d;
+ that->alphae += d;
+ }
+# endif
+ }
+
+ this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_strip_16_add(image_transform *this,
+ PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+ UNUSED(colour_type)
+
+ this->next = *that;
+ *that = this;
+
+ return bit_depth > 8;
+}
+
+IT(strip_16);
+#undef PT
+#define PT ITSTRUCT(strip_16)
+#endif /* PNG_READ_16_TO_8_SUPPORTED */
+
+#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
+/* png_set_strip_alpha */
+static void
+image_transform_png_set_strip_alpha_set(PNG_CONST image_transform *this,
+ transform_display *that, png_structp pp, png_infop pi)
+{
+ png_set_strip_alpha(pp);
+ this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_strip_alpha_mod(PNG_CONST image_transform *this,
+ image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
+{
+ if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+ that->colour_type = PNG_COLOR_TYPE_GRAY;
+ else if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA)
+ that->colour_type = PNG_COLOR_TYPE_RGB;
+
+ that->have_tRNS = 0;
+ that->alphaf = 1;
+
+ this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_strip_alpha_add(image_transform *this,
+ PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+ UNUSED(bit_depth)
+
+ this->next = *that;
+ *that = this;
+
+ return (colour_type & PNG_COLOR_MASK_ALPHA) != 0;
+}
+
+IT(strip_alpha);
+#undef PT
+#define PT ITSTRUCT(strip_alpha)
+#endif /* PNG_READ_STRIP_ALPHA_SUPPORTED */
+
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+/* png_set_rgb_to_gray(png_structp, int err_action, double red, double green)
+ * png_set_rgb_to_gray_fixed(png_structp, int err_action, png_fixed_point red,
+ * png_fixed_point green)
+ * png_get_rgb_to_gray_status
+ *
+ * The 'default' test here uses values known to be used inside libpng:
+ *
+ * red: 6968
+ * green: 23434
+ * blue: 2366
+ *
+ * These values are being retained for compatibility, along with the somewhat
+ * broken truncation calculation in the fast-and-inaccurate code path. Older
+ * versions of libpng will fail the accuracy tests below because they use the
+ * truncation algorithm everywhere.
+ */
+#define data ITDATA(rgb_to_gray)
+static struct
+{
+ double gamma; /* File gamma to use in processing */
+
+ /* The following are the parameters for png_set_rgb_to_gray: */
+# ifdef PNG_FLOATING_POINT_SUPPORTED
+ double red_to_set;
+ double green_to_set;
+# else
+ png_fixed_point red_to_set;
+ png_fixed_point green_to_set;
+# endif
+
+ /* The actual coefficients: */
+ double red_coefficient;
+ double green_coefficient;
+ double blue_coefficient;
+
+ /* Set if the coeefficients have been overridden. */
+ int coefficients_overridden;
+} data;
+
+#undef image_transform_ini
+#define image_transform_ini image_transform_png_set_rgb_to_gray_ini
+static void
+image_transform_png_set_rgb_to_gray_ini(PNG_CONST image_transform *this,
+ transform_display *that)
+{
+ png_modifier *pm = that->pm;
+ PNG_CONST color_encoding *e = pm->current_encoding;
+
+ UNUSED(this)
+
+ /* Since we check the encoding this flag must be set: */
+ pm->test_uses_encoding = 1;
+
+ /* If 'e' is not NULL chromaticity information is present and either a cHRM
+ * or an sRGB chunk will be inserted.
+ */
+ if (e != 0)
+ {
+ /* Coefficients come from the encoding, but may need to be normalized to a
+ * white point Y of 1.0
+ */
+ PNG_CONST double whiteY = e->red.Y + e->green.Y + e->blue.Y;
+
+ data.red_coefficient = e->red.Y;
+ data.green_coefficient = e->green.Y;
+ data.blue_coefficient = e->blue.Y;
+
+ if (whiteY != 1)
+ {
+ data.red_coefficient /= whiteY;
+ data.green_coefficient /= whiteY;
+ data.blue_coefficient /= whiteY;
+ }
+ }
+
+ else
+ {
+ /* The default (built in) coeffcients, as above: */
+ data.red_coefficient = 6968 / 32768.;
+ data.green_coefficient = 23434 / 32768.;
+ data.blue_coefficient = 2366 / 32768.;
+ }
+
+ data.gamma = pm->current_gamma;
+
+ /* If not set then the calculations assume linear encoding (implicitly): */
+ if (data.gamma == 0)
+ data.gamma = 1;
+
+ /* The arguments to png_set_rgb_to_gray can override the coefficients implied
+ * by the color space encoding. If doing exhaustive checks do the override
+ * in each case, otherwise do it randomly.
+ */
+ if (pm->test_exhaustive)
+ {
+ /* First time in coefficients_overridden is 0, the following sets it to 1,
+ * so repeat if it is set. If a test fails this may mean we subsequently
+ * skip a non-override test, ignore that.
+ */
+ data.coefficients_overridden = !data.coefficients_overridden;
+ pm->repeat = data.coefficients_overridden != 0;
+ }
+
+ else
+ data.coefficients_overridden = random_choice();
+
+ if (data.coefficients_overridden)
+ {
+ /* These values override the color encoding defaults, simply use random
+ * numbers.
+ */
+ png_uint_32 ru;
+ double total;
+
+ RANDOMIZE(ru);
+ data.green_coefficient = total = (ru & 0xffff) / 65535.;
+ ru >>= 16;
+ data.red_coefficient = (1 - total) * (ru & 0xffff) / 65535.;
+ total += data.red_coefficient;
+ data.blue_coefficient = 1 - total;
+
+# ifdef PNG_FLOATING_POINT_SUPPORTED
+ data.red_to_set = data.red_coefficient;
+ data.green_to_set = data.green_coefficient;
+# else
+ data.red_to_set = fix(data.red_coefficient);
+ data.green_to_set = fix(data.green_coefficient);
+# endif
+
+ /* The following just changes the error messages: */
+ pm->encoding_ignored = 1;
+ }
+
+ else
+ {
+ data.red_to_set = -1;
+ data.green_to_set = -1;
+ }
+
+ /* Adjust the error limit in the png_modifier because of the larger errors
+ * produced in the digitization during the gamma handling.
+ */
+ if (data.gamma != 1) /* Use gamma tables */
+ {
+ if (that->this.bit_depth == 16 || pm->assume_16_bit_calculations)
+ {
+ /* The 16 bit case ends up producing a maximum error of about
+ * +/-5 in 65535, allow for +/-8 with the given gamma.
+ */
+ that->pm->limit += pow(8./65535, data.gamma);
+ }
+
+ else
+ {
+ /* Rounding to 8 bits in the linear space causes massive errors which
+ * will trigger the error check in transform_range_check. Fix that
+ * here by taking the gamma encoding into account.
+ */
+ that->pm->limit += pow(1./255, data.gamma);
+ }
+ }
+
+ else
+ {
+ /* With no gamma correction a large error comes from the truncation of the
+ * calculation in the 8 bit case, allow for that here.
+ */
+ if (that->this.bit_depth != 16)
+ that->pm->limit += 4E-3;
+ }
+}
+
+static void
+image_transform_png_set_rgb_to_gray_set(PNG_CONST image_transform *this,
+ transform_display *that, png_structp pp, png_infop pi)
+{
+ PNG_CONST int error_action = 1; /* no error, no defines in png.h */
+
+# ifdef PNG_FLOATING_POINT_SUPPORTED
+ png_set_rgb_to_gray(pp, error_action, data.red_to_set, data.green_to_set);
+# else
+ png_set_rgb_to_gray_fixed(pp, error_action, data.red_to_set,
+ data.green_to_set);
+# endif
+
+# ifdef PNG_READ_cHRM_SUPPORTED
+ if (that->pm->current_encoding != 0)
+ {
+ /* We have an encoding so a cHRM chunk may have been set; if so then
+ * check that the libpng APIs give the correct (X,Y,Z) values within
+ * some margin of error for the round trip through the chromaticity
+ * form.
+ */
+# ifdef PNG_FLOATING_POINT_SUPPORTED
+# define API_function png_get_cHRM_XYZ
+# define API_form "FP"
+# define API_type double
+# define API_cvt(x) (x)
+# else
+# define API_function png_get_cHRM_XYZ_fixed
+# define API_form "fixed"
+# define API_type png_fixed_point
+# define API_cvt(x) ((double)(x)/PNG_FP_1)
+# endif
+
+ API_type rX, gX, bX;
+ API_type rY, gY, bY;
+ API_type rZ, gZ, bZ;
+
+ if ((API_function(pp, pi, &rX, &rY, &rZ, &gX, &gY, &gZ, &bX, &bY, &bZ)
+ & PNG_INFO_cHRM) != 0)
+ {
+ double maxe;
+ PNG_CONST char *el;
+ color_encoding e, o;
+
+ /* Expect libpng to return a normalized result, but the original
+ * color space encoding may not be normalized.
+ */
+ modifier_current_encoding(that->pm, &o);
+ normalize_color_encoding(&o);
+
+ /* Sanity check the pngvalid code - the coefficients should match
+ * the normalized Y values of the encoding unless they were
+ * overridden.
+ */
+ if (data.red_to_set == -1 && data.green_to_set == -1 &&
+ (fabs(o.red.Y - data.red_coefficient) > DBL_EPSILON ||
+ fabs(o.green.Y - data.green_coefficient) > DBL_EPSILON ||
+ fabs(o.blue.Y - data.blue_coefficient) > DBL_EPSILON))
+ png_error(pp, "internal pngvalid cHRM coefficient error");
+
+ /* Generate a colour space encoding. */
+ e.gamma = o.gamma; /* not used */
+ e.red.X = API_cvt(rX);
+ e.red.Y = API_cvt(rY);
+ e.red.Z = API_cvt(rZ);
+ e.green.X = API_cvt(gX);
+ e.green.Y = API_cvt(gY);
+ e.green.Z = API_cvt(gZ);
+ e.blue.X = API_cvt(bX);
+ e.blue.Y = API_cvt(bY);
+ e.blue.Z = API_cvt(bZ);
+
+ /* This should match the original one from the png_modifier, within
+ * the range permitted by the libpng fixed point representation.
+ */
+ maxe = 0;
+ el = "-"; /* Set to element name with error */
+
+# define CHECK(col,x)\
+ {\
+ double err = fabs(o.col.x - e.col.x);\
+ if (err > maxe)\
+ {\
+ maxe = err;\
+ el = #col "(" #x ")";\
+ }\
+ }
+
+ CHECK(red,X)
+ CHECK(red,Y)
+ CHECK(red,Z)
+ CHECK(green,X)
+ CHECK(green,Y)
+ CHECK(green,Z)
+ CHECK(blue,X)
+ CHECK(blue,Y)
+ CHECK(blue,Z)
+
+ /* Here in both fixed and floating cases to check the values read
+ * from the cHRm chunk. PNG uses fixed point in the cHRM chunk, so
+ * we can't expect better than +/-.5E-5 on the result, allow 1E-5.
+ */
+ if (maxe >= 1E-5)
+ {
+ size_t pos = 0;
+ char buffer[256];
+
+ pos = safecat(buffer, sizeof buffer, pos, API_form);
+ pos = safecat(buffer, sizeof buffer, pos, " cHRM ");
+ pos = safecat(buffer, sizeof buffer, pos, el);
+ pos = safecat(buffer, sizeof buffer, pos, " error: ");
+ pos = safecatd(buffer, sizeof buffer, pos, maxe, 7);
+ pos = safecat(buffer, sizeof buffer, pos, " ");
+ /* Print the color space without the gamma value: */
+ pos = safecat_color_encoding(buffer, sizeof buffer, pos, &o, 0);
+ pos = safecat(buffer, sizeof buffer, pos, " -> ");
+ pos = safecat_color_encoding(buffer, sizeof buffer, pos, &e, 0);
+
+ png_error(pp, buffer);
+ }
+ }
+ }
+# endif /* READ_cHRM */
+
+ this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_rgb_to_gray_mod(PNG_CONST image_transform *this,
+ image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
+{
+ if ((that->colour_type & PNG_COLOR_MASK_COLOR) != 0)
+ {
+ double gray, err;
+
+ if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
+ image_pixel_convert_PLTE(that);
+
+ /* Image now has RGB channels... */
+ {
+ PNG_CONST png_modifier *pm = display->pm;
+ PNG_CONST unsigned int sample_depth = that->sample_depth;
+ int isgray;
+ double r, g, b;
+ double rlo, rhi, glo, ghi, blo, bhi, graylo, grayhi;
+
+ /* Do this using interval arithmetic, otherwise it is too difficult to
+ * handle the errors correctly.
+ *
+ * To handle the gamma correction work out the upper and lower bounds
+ * of the digitized value. Assume rounding here - normally the values
+ * will be identical after this operation if there is only one
+ * transform, feel free to delete the png_error checks on this below in
+ * the future (this is just me trying to ensure it works!)
+ */
+ r = rlo = rhi = that->redf;
+ rlo -= that->rede;
+ rlo = digitize(pm, rlo, sample_depth, 1/*round*/);
+ rhi += that->rede;
+ rhi = digitize(pm, rhi, sample_depth, 1/*round*/);
+
+ g = glo = ghi = that->greenf;
+ glo -= that->greene;
+ glo = digitize(pm, glo, sample_depth, 1/*round*/);
+ ghi += that->greene;
+ ghi = digitize(pm, ghi, sample_depth, 1/*round*/);
+
+ b = blo = bhi = that->bluef;
+ blo -= that->bluee;
+ blo = digitize(pm, blo, sample_depth, 1/*round*/);
+ bhi += that->greene;
+ bhi = digitize(pm, bhi, sample_depth, 1/*round*/);
+
+ isgray = r==g && g==b;
+
+ if (data.gamma != 1)
+ {
+ PNG_CONST double power = 1/data.gamma;
+ PNG_CONST double abse = abserr(pm, sample_depth, sample_depth);
+
+ /* 'abse' is the absolute error permitted in linear calculations. It
+ * is used here to capture the error permitted in the handling
+ * (undoing) of the gamma encoding. Once again digitization occurs
+ * to handle the upper and lower bounds of the values. This is
+ * where the real errors are introduced.
+ */
+ r = pow(r, power);
+ rlo = digitize(pm, pow(rlo, power)-abse, sample_depth, 1);
+ rhi = digitize(pm, pow(rhi, power)+abse, sample_depth, 1);
+
+ g = pow(g, power);
+ glo = digitize(pm, pow(glo, power)-abse, sample_depth, 1);
+ ghi = digitize(pm, pow(ghi, power)+abse, sample_depth, 1);
+
+ b = pow(b, power);
+ blo = digitize(pm, pow(blo, power)-abse, sample_depth, 1);
+ bhi = digitize(pm, pow(bhi, power)+abse, sample_depth, 1);
+ }
+
+ /* Now calculate the actual gray values. Although the error in the
+ * coefficients depends on whether they were specified on the command
+ * line (in which case truncation to 15 bits happened) or not (rounding
+ * was used) the maxium error in an individual coefficient is always
+ * 1/32768, because even in the rounding case the requirement that
+ * coefficients add up to 32768 can cause a larger rounding error.
+ *
+ * The only time when rounding doesn't occur in 1.5.5 and later is when
+ * the non-gamma code path is used for less than 16 bit data.
+ */
+ gray = r * data.red_coefficient + g * data.green_coefficient +
+ b * data.blue_coefficient;
+
+ {
+ PNG_CONST int do_round = data.gamma != 1 || sample_depth == 16;
+ PNG_CONST double ce = 1. / 32768;
+
+ graylo = digitize(pm, rlo * (data.red_coefficient-ce) +
+ glo * (data.green_coefficient-ce) +
+ blo * (data.blue_coefficient-ce), sample_depth, do_round);
+ if (graylo <= 0)
+ graylo = 0;
+
+ grayhi = digitize(pm, rhi * (data.red_coefficient+ce) +
+ ghi * (data.green_coefficient+ce) +
+ bhi * (data.blue_coefficient+ce), sample_depth, do_round);
+ if (grayhi >= 1)
+ grayhi = 1;
+ }
+
+ /* And invert the gamma. */
+ if (data.gamma != 1)
+ {
+ PNG_CONST double power = data.gamma;
+
+ gray = pow(gray, power);
+ graylo = digitize(pm, pow(graylo, power), sample_depth, 1);
+ grayhi = digitize(pm, pow(grayhi, power), sample_depth, 1);
+ }
+
+ /* Now the error can be calculated.
+ *
+ * If r==g==b because there is no overall gamma correction libpng
+ * currently preserves the original value.
+ */
+ if (isgray)
+ err = (that->rede + that->greene + that->bluee)/3;
+
+ else
+ {
+ err = fabs(grayhi-gray);
+ if (fabs(gray - graylo) > err)
+ err = fabs(graylo-gray);
+
+ /* Check that this worked: */
+ if (err > display->pm->limit)
+ {
+ size_t pos = 0;
+ char buffer[128];
+
+ pos = safecat(buffer, sizeof buffer, pos, "rgb_to_gray error ");
+ pos = safecatd(buffer, sizeof buffer, pos, err, 6);
+ pos = safecat(buffer, sizeof buffer, pos, " exceeds limit ");
+ pos = safecatd(buffer, sizeof buffer, pos,
+ display->pm->limit, 6);
+ png_error(pp, buffer);
+ }
+ }
+ }
+
+ that->bluef = that->greenf = that->redf = gray;
+ that->bluee = that->greene = that->rede = err;
+
+ /* The sBIT is the minium of the three colour channel sBITs. */
+ if (that->red_sBIT > that->green_sBIT)
+ that->red_sBIT = that->green_sBIT;
+ if (that->red_sBIT > that->blue_sBIT)
+ that->red_sBIT = that->blue_sBIT;
+ that->blue_sBIT = that->green_sBIT = that->red_sBIT;
+
+ /* And remove the colour bit in the type: */
+ if (that->colour_type == PNG_COLOR_TYPE_RGB)
+ that->colour_type = PNG_COLOR_TYPE_GRAY;
+ else if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA)
+ that->colour_type = PNG_COLOR_TYPE_GRAY_ALPHA;
+ }
+
+ this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_rgb_to_gray_add(image_transform *this,
+ PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
+{
+ UNUSED(bit_depth)
+
+ this->next = *that;
+ *that = this;
+
+ return (colour_type & PNG_COLOR_MASK_COLOR) != 0;
+}
+
+#undef data
+IT(rgb_to_gray);
+#undef PT
+#define PT ITSTRUCT(rgb_to_gray)
+#undef image_transform_ini
+#define image_transform_ini image_transform_default_ini
+#endif /* PNG_READ_RGB_TO_GRAY_SUPPORTED */
+
+#ifdef PNG_READ_BACKGROUND_SUPPORTED
+/* png_set_background(png_structp, png_const_color_16p background_color,
+ * int background_gamma_code, int need_expand, double background_gamma)
+ * png_set_background_fixed(png_structp, png_const_color_16p background_color,
+ * int background_gamma_code, int need_expand,
+ * png_fixed_point background_gamma)
+ *
+ * As with rgb_to_gray this ignores the gamma (at present.)
+*/
+#define data ITDATA(background)
+static image_pixel data;
+
+static void
+image_transform_png_set_background_set(PNG_CONST image_transform *this,
+ transform_display *that, png_structp pp, png_infop pi)
+{
+ png_byte colour_type, bit_depth;
+ png_byte random_bytes[8]; /* 8 bytes - 64 bits - the biggest pixel */
+ png_color_16 back;
+
+ /* We need a background colour, because we don't know exactly what transforms
+ * have been set we have to supply the colour in the original file format and
+ * so we need to know what that is! The background colour is stored in the
+ * transform_display.
+ */
+ RANDOMIZE(random_bytes);
+
+ /* Read the random value, for colour type 3 the background colour is actually
+ * expressed as a 24bit rgb, not an index.
+ */
+ colour_type = that->this.colour_type;
+ if (colour_type == 3)
+ {
+ colour_type = PNG_COLOR_TYPE_RGB;
+ bit_depth = 8;
+ }
+
+ else
+ bit_depth = that->this.bit_depth;
+
+ image_pixel_init(&data, random_bytes, colour_type,
+ bit_depth, 0/*x*/, 0/*unused: palette*/);
+
+ /* Extract the background colour from this image_pixel, but make sure the
+ * unused fields of 'back' are garbage.
+ */
+ RANDOMIZE(back);
+
+ if (colour_type & PNG_COLOR_MASK_COLOR)
+ {
+ back.red = (png_uint_16)data.red;
+ back.green = (png_uint_16)data.green;
+ back.blue = (png_uint_16)data.blue;
+ }
+
+ else
+ back.gray = (png_uint_16)data.red;
+
+# ifdef PNG_FLOATING_POINT_SUPPORTED
+ png_set_background(pp, &back, PNG_BACKGROUND_GAMMA_FILE, 1/*need expand*/,
+ 0);
+# else
+ png_set_background_fixed(pp, &back, PNG_BACKGROUND_GAMMA_FILE,
+ 1/*need expand*/, 0);
+# endif
+
+ this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_background_mod(PNG_CONST image_transform *this,
+ image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
+{
+ /* Check for tRNS first: */
+ if (that->have_tRNS && that->colour_type != PNG_COLOR_TYPE_PALETTE)
+ image_pixel_add_alpha(that, &display->this);
+
+ /* This is only necessary if the alpha value is less than 1. */
+ if (that->alphaf < 1)
+ {
+ /* Now we do the background calculation without any gamma correction. */
+ if (that->alphaf <= 0)
+ {
+ that->redf = data.redf;
+ that->greenf = data.greenf;
+ that->bluef = data.bluef;
+
+ that->rede = data.rede;
+ that->greene = data.greene;
+ that->bluee = data.bluee;
+
+ that->red_sBIT= data.red_sBIT;
+ that->green_sBIT= data.green_sBIT;
+ that->blue_sBIT= data.blue_sBIT;
+ }
+
+ else /* 0 < alpha < 1 */
+ {
+ double alf = 1 - that->alphaf;
+
+ that->redf = that->redf * that->alphaf + data.redf * alf;
+ that->rede = that->rede * that->alphaf + data.rede * alf +
+ DBL_EPSILON;
+ that->greenf = that->greenf * that->alphaf + data.greenf * alf;
+ that->greene = that->greene * that->alphaf + data.greene * alf +
+ DBL_EPSILON;
+ that->bluef = that->bluef * that->alphaf + data.bluef * alf;
+ that->bluee = that->bluee * that->alphaf + data.bluee * alf +
+ DBL_EPSILON;
+ }
+
+ /* Remove the alpha type and set the alpha (not in that order.) */
+ that->alphaf = 1;
+ that->alphae = 0;
+
+ if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA)
+ that->colour_type = PNG_COLOR_TYPE_RGB;
+ else if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+ that->colour_type = PNG_COLOR_TYPE_GRAY;
+ /* PNG_COLOR_TYPE_PALETTE is not changed */
+ }
+
+ this->next->mod(this->next, that, pp, display);
+}
+
+#define image_transform_png_set_background_add image_transform_default_add
+
+#undef data
+IT(background);
+#undef PT
+#define PT ITSTRUCT(background)
+#endif /* PNG_READ_BACKGROUND_SUPPORTED */
+
+/* This may just be 'end' if all the transforms are disabled! */
+static image_transform *PNG_CONST image_transform_first = &PT;
+
+static void
+transform_enable(PNG_CONST char *name)
+{
+ /* Everything starts out enabled, so if we see an 'enable' disabled
+ * everything else the first time round.
+ */
+ static int all_disabled = 0;
+ int found_it = 0;
+ image_transform *list = image_transform_first;
+
+ while (list != &image_transform_end)
+ {
+ if (strcmp(list->name, name) == 0)
+ {
+ list->enable = 1;
+ found_it = 1;
+ }
+ else if (!all_disabled)
+ list->enable = 0;
+
+ list = list->list;
+ }
+
+ all_disabled = 1;
+
+ if (!found_it)
+ {
+ fprintf(stderr, "pngvalid: --transform-enable=%s: unknown transform\n",
+ name);
+ exit(1);
+ }
+}
+
+static void
+transform_disable(PNG_CONST char *name)
+{
+ image_transform *list = image_transform_first;
+
+ while (list != &image_transform_end)
+ {
+ if (strcmp(list->name, name) == 0)
+ {
+ list->enable = 0;
+ return;
+ }
+
+ list = list->list;
+ }
+
+ fprintf(stderr, "pngvalid: --transform-disable=%s: unknown transform\n",
+ name);
+ exit(1);
+}
+
+static void
+image_transform_reset_count(void)
+{
+ image_transform *next = image_transform_first;
+ int count = 0;
+
+ while (next != &image_transform_end)
+ {
+ next->local_use = 0;
+ next->next = 0;
+ next = next->list;
+ ++count;
+ }
+
+ /* This can only happen if we every have more than 32 transforms (excluding
+ * the end) in the list.
+ */
+ if (count > 32) abort();
+}
+
+static int
+image_transform_test_counter(png_uint_32 counter, unsigned int max)
+{
+ /* Test the list to see if there is any point contining, given a current
+ * counter and a 'max' value.
+ */
+ image_transform *next = image_transform_first;
+
+ while (next != &image_transform_end)
+ {
+ /* For max 0 or 1 continue until the counter overflows: */
+ counter >>= 1;
+
+ /* Continue if any entry hasn't reacked the max. */
+ if (max > 1 && next->local_use < max)
+ return 1;
+ next = next->list;
+ }
+
+ return max <= 1 && counter == 0;
+}
+
+static png_uint_32
+image_transform_add(PNG_CONST image_transform **this, unsigned int max,
+ png_uint_32 counter, char *name, size_t sizeof_name, size_t *pos,
+ png_byte colour_type, png_byte bit_depth)
+{
+ for (;;) /* until we manage to add something */
+ {
+ png_uint_32 mask;
+ image_transform *list;
+
+ /* Find the next counter value, if the counter is zero this is the start
+ * of the list. This routine always returns the current counter (not the
+ * next) so it returns 0 at the end and expects 0 at the beginning.
+ */
+ if (counter == 0) /* first time */
+ {
+ image_transform_reset_count();
+ if (max <= 1)
+ counter = 1;
+ else
+ counter = random_32();
+ }
+ else /* advance the counter */
+ {
+ switch (max)
+ {
+ case 0: ++counter; break;
+ case 1: counter <<= 1; break;
+ default: counter = random_32(); break;
+ }
+ }
+
+ /* Now add all these items, if possible */
+ *this = &image_transform_end;
+ list = image_transform_first;
+ mask = 1;
+
+ /* Go through the whole list adding anything that the counter selects: */
+ while (list != &image_transform_end)
+ {
+ if ((counter & mask) != 0 && list->enable &&
+ (max == 0 || list->local_use < max))
+ {
+ /* Candidate to add: */
+ if (list->add(list, this, colour_type, bit_depth) || max == 0)
+ {
+ /* Added, so add to the name too. */
+ *pos = safecat(name, sizeof_name, *pos, " +");
+ *pos = safecat(name, sizeof_name, *pos, list->name);
+ }
+
+ else
+ {
+ /* Not useful and max>0, so remove it from *this: */
+ *this = list->next;
+ list->next = 0;
+
+ /* And, since we know it isn't useful, stop it being added again
+ * in this run:
+ */
+ list->local_use = max;
+ }
+ }
+
+ mask <<= 1;
+ list = list->list;
+ }
+
+ /* Now if anything was added we have something to do. */
+ if (*this != &image_transform_end)
+ return counter;
+
+ /* Nothing added, but was there anything in there to add? */
+ if (!image_transform_test_counter(counter, max))
+ return 0;
+ }
+}
+
+#ifdef THIS_IS_THE_PROFORMA
+static void
+image_transform_png_set_@_set(PNG_CONST image_transform *this,
+ transform_display *that, png_structp pp, png_infop pi)
+{
+ png_set_@(pp);
+ this->next->set(this->next, that, pp, pi);
+}
+
+static void
+image_transform_png_set_@_mod(PNG_CONST image_transform *this,
+ image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
+{
+ this->next->mod(this->next, that, pp, display);
+}
+
+static int
+image_transform_png_set_@_add(image_transform *this,
+ PNG_CONST image_transform **that, char *name, size_t sizeof_name,
+ size_t *pos, png_byte colour_type, png_byte bit_depth)
+{
+ this->next = *that;
+ *that = this;
+
+ *pos = safecat(name, sizeof_name, *pos, " +@");
+
+ return 1;
+}
+
+IT(@);
+#endif
+
+/* png_set_quantize(png_structp, png_colorp palette, int num_palette,
+ * int maximum_colors, png_const_uint_16p histogram, int full_quantize)
+ *
+ * Very difficult to validate this!
+ */
+/*NOTE: TBD NYI */
+
+/* The data layout transforms are handled by swapping our own channel data,
+ * necessarily these need to happen at the end of the transform list because the
+ * semantic of the channels changes after these are executed. Some of these,
+ * like set_shift and set_packing, can't be done at present because they change
+ * the layout of the data at the sub-sample level so sample() won't get the
+ * right answer.
+ */
+/* png_set_invert_alpha */
+/*NOTE: TBD NYI */
+
+/* png_set_bgr */
+/*NOTE: TBD NYI */
+
+/* png_set_swap_alpha */
+/*NOTE: TBD NYI */
+
+/* png_set_swap */
+/*NOTE: TBD NYI */
+
+/* png_set_filler, (png_structp png_ptr, png_uint_32 filler, int flags)); */
+/*NOTE: TBD NYI */
+
+/* png_set_add_alpha, (png_structp png_ptr, png_uint_32 filler, int flags)); */
+/*NOTE: TBD NYI */
+
+/* png_set_packing */
+/*NOTE: TBD NYI */
+
+/* png_set_packswap */
+/*NOTE: TBD NYI */
+
+/* png_set_invert_mono */
+/*NOTE: TBD NYI */
+
+/* png_set_shift(png_structp, png_const_color_8p true_bits) */
+/*NOTE: TBD NYI */
+
+static void
+perform_transform_test(png_modifier *pm)
+{
+ png_byte colour_type = 0;
+ png_byte bit_depth = 0;
+ int palette_number = 0;
+
+ while (next_format(&colour_type, &bit_depth, &palette_number))
+ {
+ png_uint_32 counter = 0;
+ size_t base_pos;
+ char name[64];
+
+ base_pos = safecat(name, sizeof name, 0, "transform:");
+
+ for (;;)
+ {
+ size_t pos = base_pos;
+ PNG_CONST image_transform *list = 0;
+
+ /* 'max' is currently hardwired to '1'; this should be settable on the
+ * command line.
+ */
+ counter = image_transform_add(&list, 1/*max*/, counter,
+ name, sizeof name, &pos, colour_type, bit_depth);
+
+ if (counter == 0)
+ break;
+
+ /* The command line can change this to checking interlaced images. */
+ do
+ {
+ pm->repeat = 0;
+ transform_test(pm, FILEID(colour_type, bit_depth, palette_number,
+ pm->interlace_type, 0, 0, 0), list, name);
+
+ if (fail(pm))
+ return;
+ }
+ while (pm->repeat);
+ }
+ }
+}
+#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
+
+/********************************* GAMMA TESTS ********************************/
+#ifdef PNG_READ_GAMMA_SUPPORTED
+/* Reader callbacks and implementations, where they differ from the standard
+ * ones.
+ */
+typedef struct gamma_display
+{
+ standard_display this;
+
+ /* Parameters */
+ png_modifier* pm;
+ double file_gamma;
+ double screen_gamma;
+ double background_gamma;
+ png_byte sbit;
+ int threshold_test;
+ int use_input_precision;
+ int scale16;
+ int expand16;
+ int do_background;
+ png_color_16 background_color;
+
+ /* Local variables */
+ double maxerrout;
+ double maxerrpc;
+ double maxerrabs;
+} gamma_display;
+
+#define ALPHA_MODE_OFFSET 4
+
+static void
+gamma_display_init(gamma_display *dp, png_modifier *pm, png_uint_32 id,
+ double file_gamma, double screen_gamma, png_byte sbit, int threshold_test,
+ int use_input_precision, int scale16, int expand16,
+ int do_background, PNG_CONST png_color_16 *pointer_to_the_background_color,
+ double background_gamma)
+{
+ /* Standard fields */
+ standard_display_init(&dp->this, &pm->this, id, 0/*do_interlace*/,
+ pm->use_update_info);
+
+ /* Parameter fields */
+ dp->pm = pm;
+ dp->file_gamma = file_gamma;
+ dp->screen_gamma = screen_gamma;
+ dp->background_gamma = background_gamma;
+ dp->sbit = sbit;
+ dp->threshold_test = threshold_test;
+ dp->use_input_precision = use_input_precision;
+ dp->scale16 = scale16;
+ dp->expand16 = expand16;
+ dp->do_background = do_background;
+ if (do_background && pointer_to_the_background_color != 0)
+ dp->background_color = *pointer_to_the_background_color;
+ else
+ memset(&dp->background_color, 0, sizeof dp->background_color);
+
+ /* Local variable fields */
+ dp->maxerrout = dp->maxerrpc = dp->maxerrabs = 0;
+}
+
+static void
+gamma_info_imp(gamma_display *dp, png_structp pp, png_infop pi)
+{
+ /* Reuse the standard stuff as appropriate. */
+ standard_info_part1(&dp->this, pp, pi);
+
+ /* If requested strip 16 to 8 bits - this is handled automagically below
+ * because the output bit depth is read from the library. Note that there
+ * are interactions with sBIT but, internally, libpng makes sbit at most
+ * PNG_MAX_GAMMA_8 when doing the following.
+ */
+ if (dp->scale16)
+# ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
+ png_set_scale_16(pp);
+# else
+ /* The following works both in 1.5.4 and earlier versions: */
+# ifdef PNG_READ_16_TO_8_SUPPORTED
+ png_set_strip_16(pp);
+# else
+ png_error(pp, "scale16 (16 to 8 bit conversion) not supported");
+# endif
+# endif
+
+ if (dp->expand16)
+# ifdef PNG_READ_EXPAND_16_SUPPORTED
+ png_set_expand_16(pp);
+# else
+ png_error(pp, "expand16 (8 to 16 bit conversion) not supported");
+# endif
+
+ if (dp->do_background >= ALPHA_MODE_OFFSET)
+ {
+# ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+ {
+ /* This tests the alpha mode handling, if supported. */
+ int mode = dp->do_background - ALPHA_MODE_OFFSET;
+
+ /* The gamma value is the output gamma, and is in the standard,
+ * non-inverted, represenation. It provides a default for the PNG file
+ * gamma, but since the file has a gAMA chunk this does not matter.
+ */
+ PNG_CONST double sg = dp->screen_gamma;
+# ifndef PNG_FLOATING_POINT_SUPPORTED
+ PNG_CONST png_fixed_point g = fix(sg);
+# endif
+
+# ifdef PNG_FLOATING_POINT_SUPPORTED
+ png_set_alpha_mode(pp, mode, sg);
+# else
+ png_set_alpha_mode_fixed(pp, mode, g);
+# endif
+
+ /* However, for the standard Porter-Duff algorithm the output defaults
+ * to be linear, so if the test requires non-linear output it must be
+ * corrected here.
+ */
+ if (mode == PNG_ALPHA_STANDARD && sg != 1)
+ {
+# ifdef PNG_FLOATING_POINT_SUPPORTED
+ png_set_gamma(pp, sg, dp->file_gamma);
+# else
+ png_fixed_point f = fix(dp->file_gamma);
+ png_set_gamma_fixed(pp, g, f);
+# endif
+ }
+ }
+# else
+ png_error(pp, "alpha mode handling not supported");
+# endif
+ }
+
+ else
+ {
+ /* Set up gamma processing. */
+# ifdef PNG_FLOATING_POINT_SUPPORTED
+ png_set_gamma(pp, dp->screen_gamma, dp->file_gamma);
+# else
+ {
+ png_fixed_point s = fix(dp->screen_gamma);
+ png_fixed_point f = fix(dp->file_gamma);
+ png_set_gamma_fixed(pp, s, f);
+ }
+# endif
+
+ if (dp->do_background)
+ {
+# ifdef PNG_READ_BACKGROUND_SUPPORTED
+ /* NOTE: this assumes the caller provided the correct background gamma!
+ */
+ PNG_CONST double bg = dp->background_gamma;
+# ifndef PNG_FLOATING_POINT_SUPPORTED
+ PNG_CONST png_fixed_point g = fix(bg);
+# endif
+
+# ifdef PNG_FLOATING_POINT_SUPPORTED
+ png_set_background(pp, &dp->background_color, dp->do_background,
+ 0/*need_expand*/, bg);
+# else
+ png_set_background_fixed(pp, &dp->background_color,
+ dp->do_background, 0/*need_expand*/, g);
+# endif
+# else
+ png_error(pp, "png_set_background not supported");
+# endif
+ }
+ }
+
+ {
+ int i = dp->this.use_update_info;
+ /* Always do one call, even if use_update_info is 0. */
+ do
+ png_read_update_info(pp, pi);
+ while (--i > 0);
+ }
+
+ /* Now we may get a different cbRow: */
+ standard_info_part2(&dp->this, pp, pi, 1 /*images*/);
+}
+
+static void
+gamma_info(png_structp pp, png_infop pi)
+{
+ gamma_info_imp(voidcast(gamma_display*, png_get_progressive_ptr(pp)), pp,
+ pi);
+}
+
+/* Validate a single component value - the routine gets the input and output
+ * sample values as unscaled PNG component values along with a cache of all the
+ * information required to validate the values.
+ */
+typedef struct validate_info
+{
+ png_structp pp;
+ gamma_display *dp;
+ png_byte sbit;
+ int use_input_precision;
+ int do_background;
+ int scale16;
+ unsigned int sbit_max;
+ unsigned int isbit_shift;
+ unsigned int outmax;
+
+ double gamma_correction; /* Overall correction required. */
+ double file_inverse; /* Inverse of file gamma. */
+ double screen_gamma;
+ double screen_inverse; /* Inverse of screen gamma. */
+
+ double background_red; /* Linear background value, red or gray. */
+ double background_green;
+ double background_blue;
+
+ double maxabs;
+ double maxpc;
+ double maxcalc;
+ double maxout;
+ double maxout_total; /* Total including quantization error */
+ double outlog;
+ int outquant;
+}
+validate_info;
+
+static void
+init_validate_info(validate_info *vi, gamma_display *dp, png_struct *pp,
+ int in_depth, int out_depth)
+{
+ PNG_CONST unsigned int outmax = (1U<<out_depth)-1;
+
+ vi->pp = pp;
+ vi->dp = dp;
+
+ if (dp->sbit > 0 && dp->sbit < in_depth)
+ {
+ vi->sbit = dp->sbit;
+ vi->isbit_shift = in_depth - dp->sbit;
+ }
+
+ else
+ {
+ vi->sbit = (png_byte)in_depth;
+ vi->isbit_shift = 0;
+ }
+
+ vi->sbit_max = (1U << vi->sbit)-1;
+
+ /* This mimics the libpng threshold test, '0' is used to prevent gamma
+ * correction in the validation test.
+ */
+ vi->screen_gamma = dp->screen_gamma;
+ if (fabs(vi->screen_gamma-1) < PNG_GAMMA_THRESHOLD)
+ vi->screen_gamma = vi->screen_inverse = 0;
+ else
+ vi->screen_inverse = 1/vi->screen_gamma;
+
+ vi->use_input_precision = dp->use_input_precision;
+ vi->outmax = outmax;
+ vi->maxabs = abserr(dp->pm, in_depth, out_depth);
+ vi->maxpc = pcerr(dp->pm, in_depth, out_depth);
+ vi->maxcalc = calcerr(dp->pm, in_depth, out_depth);
+ vi->maxout = outerr(dp->pm, in_depth, out_depth);
+ vi->outquant = output_quantization_factor(dp->pm, in_depth, out_depth);
+ vi->maxout_total = vi->maxout + vi->outquant * .5;
+ vi->outlog = outlog(dp->pm, in_depth, out_depth);
+
+ if ((dp->this.colour_type & PNG_COLOR_MASK_ALPHA) != 0 ||
+ (dp->this.colour_type == 3 && dp->this.is_transparent))
+ {
+ vi->do_background = dp->do_background;
+
+ if (vi->do_background != 0)
+ {
+ PNG_CONST double bg_inverse = 1/dp->background_gamma;
+ double r, g, b;
+
+ /* Caller must at least put the gray value into the red channel */
+ r = dp->background_color.red; r /= outmax;
+ g = dp->background_color.green; g /= outmax;
+ b = dp->background_color.blue; b /= outmax;
+
+# if 0
+ /* libpng doesn't do this optimization, if we do pngvalid will fail.
+ */
+ if (fabs(bg_inverse-1) >= PNG_GAMMA_THRESHOLD)
+# endif
+ {
+ r = pow(r, bg_inverse);
+ g = pow(g, bg_inverse);
+ b = pow(b, bg_inverse);
+ }
+
+ vi->background_red = r;
+ vi->background_green = g;
+ vi->background_blue = b;
+ }
+ }
+ else
+ vi->do_background = 0;
+
+ if (vi->do_background == 0)
+ vi->background_red = vi->background_green = vi->background_blue = 0;
+
+ vi->gamma_correction = 1/(dp->file_gamma*dp->screen_gamma);
+ if (fabs(vi->gamma_correction-1) < PNG_GAMMA_THRESHOLD)
+ vi->gamma_correction = 0;
+
+ vi->file_inverse = 1/dp->file_gamma;
+ if (fabs(vi->file_inverse-1) < PNG_GAMMA_THRESHOLD)
+ vi->file_inverse = 0;
+
+ vi->scale16 = dp->scale16;
+}
+
+/* This function handles composition of a single non-alpha component. The
+ * argument is the input sample value, in the range 0..1, and the alpha value.
+ * The result is the composed, linear, input sample. If alpha is less than zero
+ * this is the alpha component and the function should not be called!
+ */
+static double
+gamma_component_compose(int do_background, double input_sample, double alpha,
+ double background, int *compose)
+{
+ switch (do_background)
+ {
+ case PNG_BACKGROUND_GAMMA_SCREEN:
+ case PNG_BACKGROUND_GAMMA_FILE:
+ case PNG_BACKGROUND_GAMMA_UNIQUE:
+ /* Standard PNG background processing. */
+ if (alpha < 1)
+ {
+ if (alpha > 0)
+ {
+ input_sample = input_sample * alpha + background * (1-alpha);
+ if (compose != NULL)
+ *compose = 1;
+ }
+
+ else
+ input_sample = background;
+ }
+ break;
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+ case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD:
+ case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN:
+ /* The components are premultiplied in either case and the output is
+ * gamma encoded (to get standard Porter-Duff we expect the output
+ * gamma to be set to 1.0!)
+ */
+ case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED:
+ /* The optimization is that the partial-alpha entries are linear
+ * while the opaque pixels are gamma encoded, but this only affects the
+ * output encoding.
+ */
+ if (alpha < 1)
+ {
+ if (alpha > 0)
+ {
+ input_sample *= alpha;
+ if (compose != NULL)
+ *compose = 1;
+ }
+
+ else
+ input_sample = 0;
+ }
+ break;
+#endif
+
+ default:
+ /* Standard cases where no compositing is done (so the component
+ * value is already correct.)
+ */
+ break;
+ }
+
+ return input_sample;
+}
+
+/* This API returns the encoded *input* component, in the range 0..1 */
+static double
+gamma_component_validate(PNG_CONST char *name, PNG_CONST validate_info *vi,
+ PNG_CONST unsigned int id, PNG_CONST unsigned int od,
+ PNG_CONST double alpha /* <0 for the alpha channel itself */,
+ PNG_CONST double background /* component background value */)
+{
+ PNG_CONST unsigned int isbit = id >> vi->isbit_shift;
+ PNG_CONST unsigned int sbit_max = vi->sbit_max;
+ PNG_CONST unsigned int outmax = vi->outmax;
+ PNG_CONST int do_background = vi->do_background;
+
+ double i;
+
+ /* First check on the 'perfect' result obtained from the digitized input
+ * value, id, and compare this against the actual digitized result, 'od'.
+ * 'i' is the input result in the range 0..1:
+ */
+ i = isbit; i /= sbit_max;
+
+ /* Check for the fast route: if we don't do any background composition or if
+ * this is the alpha channel ('alpha' < 0) or if the pixel is opaque then
+ * just use the gamma_correction field to correct to the final output gamma.
+ */
+ if (alpha == 1 /* opaque pixel component */ || !do_background
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+ || do_background == ALPHA_MODE_OFFSET + PNG_ALPHA_PNG
+#endif
+ || (alpha < 0 /* alpha channel */
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+ && do_background != ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN
+#endif
+ ))
+ {
+ /* Then get the gamma corrected version of 'i' and compare to 'od', any
+ * error less than .5 is insignificant - just quantization of the output
+ * value to the nearest digital value (nevertheless the error is still
+ * recorded - it's interesting ;-)
+ */
+ double encoded_sample = i;
+ double encoded_error;
+
+ /* alpha less than 0 indicates the alpha channel, which is always linear
+ */
+ if (alpha >= 0 && vi->gamma_correction > 0)
+ encoded_sample = pow(encoded_sample, vi->gamma_correction);
+ encoded_sample *= outmax;
+
+ encoded_error = fabs(od-encoded_sample);
+
+ if (encoded_error > vi->dp->maxerrout)
+ vi->dp->maxerrout = encoded_error;
+
+ if (encoded_error < vi->maxout_total && encoded_error < vi->outlog)
+ return i;
+ }
+
+ /* The slow route - attempt to do linear calculations. */
+ /* There may be an error, or background processing is required, so calculate
+ * the actual sample values - unencoded light intensity values. Note that in
+ * practice these are not completely unencoded because they include a
+ * 'viewing correction' to decrease or (normally) increase the perceptual
+ * contrast of the image. There's nothing we can do about this - we don't
+ * know what it is - so assume the unencoded value is perceptually linear.
+ */
+ {
+ double input_sample = i; /* In range 0..1 */
+ double output, error, encoded_sample, encoded_error;
+ double es_lo, es_hi;
+ int compose = 0; /* Set to one if composition done */
+ int output_is_encoded; /* Set if encoded to screen gamma */
+ int log_max_error = 1; /* Check maximum error values */
+ png_const_charp pass = 0; /* Reason test passes (or 0 for fail) */
+
+ /* Convert to linear light (with the above caveat.) The alpha channel is
+ * already linear.
+ */
+ if (alpha >= 0)
+ {
+ int tcompose;
+
+ if (vi->file_inverse > 0)
+ input_sample = pow(input_sample, vi->file_inverse);
+
+ /* Handle the compose processing: */
+ tcompose = 0;
+ input_sample = gamma_component_compose(do_background, input_sample,
+ alpha, background, &tcompose);
+
+ if (tcompose)
+ compose = 1;
+ }
+
+ /* And similarly for the output value, but we need to check the background
+ * handling to linearize it correctly.
+ */
+ output = od;
+ output /= outmax;
+
+ output_is_encoded = vi->screen_gamma > 0;
+
+ if (alpha < 0) /* The alpha channel */
+ {
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+ if (do_background != ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN)
+#endif
+ {
+ /* In all other cases the output alpha channel is linear already,
+ * don't log errors here, they are much larger in linear data.
+ */
+ output_is_encoded = 0;
+ log_max_error = 0;
+ }
+ }
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+ else /* A component */
+ {
+ if (do_background == ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED &&
+ alpha < 1) /* the optimized case - linear output */
+ {
+ if (alpha > 0) log_max_error = 0;
+ output_is_encoded = 0;
+ }
+ }
+#endif
+
+ if (output_is_encoded)
+ output = pow(output, vi->screen_gamma);
+
+ /* Calculate (or recalculate) the encoded_sample value and repeat the
+ * check above (unnecessary if we took the fast route, but harmless.)
+ */
+ encoded_sample = input_sample;
+ if (output_is_encoded)
+ encoded_sample = pow(encoded_sample, vi->screen_inverse);
+ encoded_sample *= outmax;
+
+ encoded_error = fabs(od-encoded_sample);
+
+ /* Don't log errors in the alpha channel, or the 'optimized' case,
+ * neither are significant to the overall perception.
+ */
+ if (log_max_error && encoded_error > vi->dp->maxerrout)
+ vi->dp->maxerrout = encoded_error;
+
+ if (encoded_error < vi->maxout_total)
+ {
+ if (encoded_error < vi->outlog)
+ return i;
+
+ /* Test passed but error is bigger than the log limit, record why the
+ * test passed:
+ */
+ pass = "less than maxout:\n";
+ }
+
+ /* i: the original input value in the range 0..1
+ *
+ * pngvalid calculations:
+ * input_sample: linear result; i linearized and composed, range 0..1
+ * encoded_sample: encoded result; input_sample scaled to ouput bit depth
+ *
+ * libpng calculations:
+ * output: linear result; od scaled to 0..1 and linearized
+ * od: encoded result from libpng
+ */
+
+ /* Now we have the numbers for real errors, both absolute values as as a
+ * percentage of the correct value (output):
+ */
+ error = fabs(input_sample-output);
+
+ if (log_max_error && error > vi->dp->maxerrabs)
+ vi->dp->maxerrabs = error;
+
+ /* The following is an attempt to ignore the tendency of quantization to
+ * dominate the percentage errors for lower result values:
+ */
+ if (log_max_error && input_sample > .5)
+ {
+ double percentage_error = error/input_sample;
+ if (percentage_error > vi->dp->maxerrpc)
+ vi->dp->maxerrpc = percentage_error;
+ }
+
+ /* Now calculate the digitization limits for 'encoded_sample' using the
+ * 'max' values. Note that maxout is in the encoded space but maxpc and
+ * maxabs are in linear light space.
+ *
+ * First find the maximum error in linear light space, range 0..1:
+ */
+ {
+ double tmp = input_sample * vi->maxpc;
+ if (tmp < vi->maxabs) tmp = vi->maxabs;
+ /* If 'compose' is true the composition was done in linear space using
+ * integer arithmetic. This introduces an extra error of +/- 0.5 (at
+ * least) in the integer space used. 'maxcalc' records this, taking
+ * into account the possibility that even for 16 bit output 8 bit space
+ * may have been used.
+ */
+ if (compose && tmp < vi->maxcalc) tmp = vi->maxcalc;
+
+ /* The 'maxout' value refers to the encoded result, to compare with
+ * this encode input_sample adjusted by the maximum error (tmp) above.
+ */
+ es_lo = encoded_sample - vi->maxout;
+
+ if (es_lo > 0 && input_sample-tmp > 0)
+ {
+ double low_value = input_sample-tmp;
+ if (output_is_encoded)
+ low_value = pow(low_value, vi->screen_inverse);
+ low_value *= outmax;
+ if (low_value < es_lo) es_lo = low_value;
+
+ /* Quantize this appropriately: */
+ es_lo = ceil(es_lo / vi->outquant - .5) * vi->outquant;
+ }
+
+ else
+ es_lo = 0;
+
+ es_hi = encoded_sample + vi->maxout;
+
+ if (es_hi < outmax && input_sample+tmp < 1)
+ {
+ double high_value = input_sample+tmp;
+ if (output_is_encoded)
+ high_value = pow(high_value, vi->screen_inverse);
+ high_value *= outmax;
+ if (high_value > es_hi) es_hi = high_value;
+
+ es_hi = floor(es_hi / vi->outquant + .5) * vi->outquant;
+ }
+
+ else
+ es_hi = outmax;
+ }
+
+ /* The primary test is that the final encoded value returned by the
+ * library should be between the two limits (inclusive) that were
+ * calculated above.
+ */
+ if (od >= es_lo && od <= es_hi)
+ {
+ /* The value passes, but we may need to log the information anyway. */
+ if (encoded_error < vi->outlog)
+ return i;
+
+ if (pass == 0)
+ pass = "within digitization limits:\n";
+ }
+
+ {
+ /* There has been an error in processing, or we need to log this
+ * value.
+ */
+ double is_lo, is_hi;
+
+ /* pass is set at this point if either of the tests above would have
+ * passed. Don't do these additional tests here - just log the
+ * original [es_lo..es_hi] values.
+ */
+ if (pass == 0 && vi->use_input_precision)
+ {
+ /* Ok, something is wrong - this actually happens in current libpng
+ * 16-to-8 processing. Assume that the input value (id, adjusted
+ * for sbit) can be anywhere between value-.5 and value+.5 - quite a
+ * large range if sbit is low.
+ */
+ double tmp = (isbit - .5)/sbit_max;
+
+ if (tmp <= 0)
+ tmp = 0;
+
+ else if (alpha >= 0 && vi->file_inverse > 0 && tmp < 1)
+ tmp = pow(tmp, vi->file_inverse);
+
+ tmp = gamma_component_compose(do_background, tmp, alpha, background,
+ NULL);
+
+ if (output_is_encoded && tmp > 0 && tmp < 1)
+ tmp = pow(tmp, vi->screen_inverse);
+
+ is_lo = ceil(outmax * tmp - vi->maxout_total);
+
+ if (is_lo < 0)
+ is_lo = 0;
+
+ tmp = (isbit + .5)/sbit_max;
+
+ if (tmp <= 0)
+ tmp = 0;
+
+ else if (alpha >= 0 && vi->file_inverse > 0 && tmp < 1)
+ tmp = pow(tmp, vi->file_inverse);
+
+ tmp = gamma_component_compose(do_background, tmp, alpha, background,
+ NULL);
+
+ if (output_is_encoded && tmp > 0 && tmp < 1)
+ tmp = pow(tmp, vi->screen_inverse);
+
+ is_hi = floor(outmax * tmp + vi->maxout_total);
+
+ if (is_hi > outmax)
+ is_hi = outmax;
+
+ if (!(od < is_lo || od > is_hi))
+ {
+ if (encoded_error < vi->outlog)
+ return i;
+
+ pass = "within input precision limits:\n";
+ }
+
+ /* One last chance. If this is an alpha channel and the 16to8
+ * option has been used and 'inaccurate' scaling is used then the
+ * bit reduction is obtained by simply using the top 8 bits of the
+ * value.
+ *
+ * This is only done for older libpng versions when the 'inaccurate'
+ * (chop) method of scaling was used.
+ */
+# ifndef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
+# if PNG_LIBPNG_VER < 10504
+ /* This may be required for other components in the future,
+ * but at present the presence of gamma correction effectively
+ * prevents the errors in the component scaling (I don't quite
+ * understand why, but since it's better this way I care not
+ * to ask, JB 20110419.)
+ */
+ if (pass == 0 && alpha < 0 && vi->scale16 && vi->sbit > 8 &&
+ vi->sbit + vi->isbit_shift == 16)
+ {
+ tmp = ((id >> 8) - .5)/255;
+
+ if (tmp > 0)
+ {
+ is_lo = ceil(outmax * tmp - vi->maxout_total);
+ if (is_lo < 0) is_lo = 0;
+ }
+
+ else
+ is_lo = 0;
+
+ tmp = ((id >> 8) + .5)/255;
+
+ if (tmp < 1)
+ {
+ is_hi = floor(outmax * tmp + vi->maxout_total);
+ if (is_hi > outmax) is_hi = outmax;
+ }
+
+ else
+ is_hi = outmax;
+
+ if (!(od < is_lo || od > is_hi))
+ {
+ if (encoded_error < vi->outlog)
+ return i;
+
+ pass = "within 8 bit limits:\n";
+ }
+ }
+# endif
+# endif
+ }
+ else /* !use_input_precision */
+ is_lo = es_lo, is_hi = es_hi;
+
+ /* Attempt to output a meaningful error/warning message: the message
+ * output depends on the background/composite operation being performed
+ * because this changes what parameters were actually used above.
+ */
+ {
+ size_t pos = 0;
+ /* Need either 1/255 or 1/65535 precision here; 3 or 6 decimal
+ * places. Just use outmax to work out which.
+ */
+ int precision = (outmax >= 1000 ? 6 : 3);
+ int use_input=1, use_background=0, do_compose=0;
+ char msg[256];
+
+ if (pass != 0)
+ pos = safecat(msg, sizeof msg, pos, "\n\t");
+
+ /* Set up the various flags, the output_is_encoded flag above
+ * is also used below. do_compose is just a double check.
+ */
+ switch (do_background)
+ {
+ case PNG_BACKGROUND_GAMMA_SCREEN:
+ case PNG_BACKGROUND_GAMMA_FILE:
+ case PNG_BACKGROUND_GAMMA_UNIQUE:
+ use_background = (alpha >= 0 && alpha < 1);
+ /*FALL THROUGH*/
+# ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+ case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD:
+ case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN:
+ case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED:
+# endif /* ALPHA_MODE_SUPPORTED */
+ do_compose = (alpha > 0 && alpha < 1);
+ use_input = (alpha != 0);
+ break;
+
+ default:
+ break;
+ }
+
+ /* Check the 'compose' flag */
+ if (compose != do_compose)
+ png_error(vi->pp, "internal error (compose)");
+
+ /* 'name' is the component name */
+ pos = safecat(msg, sizeof msg, pos, name);
+ pos = safecat(msg, sizeof msg, pos, "(");
+ pos = safecatn(msg, sizeof msg, pos, id);
+ if (use_input || pass != 0/*logging*/)
+ {
+ if (isbit != id)
+ {
+ /* sBIT has reduced the precision of the input: */
+ pos = safecat(msg, sizeof msg, pos, ", sbit(");
+ pos = safecatn(msg, sizeof msg, pos, vi->sbit);
+ pos = safecat(msg, sizeof msg, pos, "): ");
+ pos = safecatn(msg, sizeof msg, pos, isbit);
+ }
+ pos = safecat(msg, sizeof msg, pos, "/");
+ /* The output is either "id/max" or "id sbit(sbit): isbit/max" */
+ pos = safecatn(msg, sizeof msg, pos, vi->sbit_max);
+ }
+ pos = safecat(msg, sizeof msg, pos, ")");
+
+ /* A component may have been multiplied (in linear space) by the
+ * alpha value, 'compose' says whether this is relevant.
+ */
+ if (compose || pass != 0)
+ {
+ /* If any form of composition is being done report our
+ * calculated linear value here (the code above doesn't record
+ * the input value before composition is performed, so what
+ * gets reported is the value after composition.)
+ */
+ if (use_input || pass != 0)
+ {
+ if (vi->file_inverse > 0)
+ {
+ pos = safecat(msg, sizeof msg, pos, "^");
+ pos = safecatd(msg, sizeof msg, pos, vi->file_inverse, 2);
+ }
+
+ else
+ pos = safecat(msg, sizeof msg, pos, "[linear]");
+
+ pos = safecat(msg, sizeof msg, pos, "*(alpha)");
+ pos = safecatd(msg, sizeof msg, pos, alpha, precision);
+ }
+
+ /* Now record the *linear* background value if it was used
+ * (this function is not passed the original, non-linear,
+ * value but it is contained in the test name.)
+ */
+ if (use_background)
+ {
+ pos = safecat(msg, sizeof msg, pos, use_input ? "+" : " ");
+ pos = safecat(msg, sizeof msg, pos, "(background)");
+ pos = safecatd(msg, sizeof msg, pos, background, precision);
+ pos = safecat(msg, sizeof msg, pos, "*");
+ pos = safecatd(msg, sizeof msg, pos, 1-alpha, precision);
+ }
+ }
+
+ /* Report the calculated value (input_sample) and the linearized
+ * libpng value (output) unless this is just a component gamma
+ * correction.
+ */
+ if (compose || alpha < 0 || pass != 0)
+ {
+ pos = safecat(msg, sizeof msg, pos,
+ pass != 0 ? " =\n\t" : " = ");
+ pos = safecatd(msg, sizeof msg, pos, input_sample, precision);
+ pos = safecat(msg, sizeof msg, pos, " (libpng: ");
+ pos = safecatd(msg, sizeof msg, pos, output, precision);
+ pos = safecat(msg, sizeof msg, pos, ")");
+
+ /* Finally report the output gamma encoding, if any. */
+ if (output_is_encoded)
+ {
+ pos = safecat(msg, sizeof msg, pos, " ^");
+ pos = safecatd(msg, sizeof msg, pos, vi->screen_inverse, 2);
+ pos = safecat(msg, sizeof msg, pos, "(to screen) =");
+ }
+
+ else
+ pos = safecat(msg, sizeof msg, pos, " [screen is linear] =");
+ }
+
+ if ((!compose && alpha >= 0) || pass != 0)
+ {
+ if (pass != 0) /* logging */
+ pos = safecat(msg, sizeof msg, pos, "\n\t[overall:");
+
+ /* This is the non-composition case, the internal linear
+ * values are irrelevant (though the log below will reveal
+ * them.) Output a much shorter warning/error message and report
+ * the overall gamma correction.
+ */
+ if (vi->gamma_correction > 0)
+ {
+ pos = safecat(msg, sizeof msg, pos, " ^");
+ pos = safecatd(msg, sizeof msg, pos, vi->gamma_correction, 2);
+ pos = safecat(msg, sizeof msg, pos, "(gamma correction) =");
+ }
+
+ else
+ pos = safecat(msg, sizeof msg, pos,
+ " [no gamma correction] =");
+
+ if (pass != 0)
+ pos = safecat(msg, sizeof msg, pos, "]");
+ }
+
+ /* This is our calculated encoded_sample which should (but does
+ * not) match od:
+ */
+ pos = safecat(msg, sizeof msg, pos, pass != 0 ? "\n\t" : " ");
+ pos = safecatd(msg, sizeof msg, pos, is_lo, 1);
+ pos = safecat(msg, sizeof msg, pos, " < ");
+ pos = safecatd(msg, sizeof msg, pos, encoded_sample, 1);
+ pos = safecat(msg, sizeof msg, pos, " (libpng: ");
+ pos = safecatn(msg, sizeof msg, pos, od);
+ pos = safecat(msg, sizeof msg, pos, ")");
+ pos = safecat(msg, sizeof msg, pos, "/");
+ pos = safecatn(msg, sizeof msg, pos, outmax);
+ pos = safecat(msg, sizeof msg, pos, " < ");
+ pos = safecatd(msg, sizeof msg, pos, is_hi, 1);
+
+ if (pass == 0) /* The error condition */
+ {
+# ifdef PNG_WARNINGS_SUPPORTED
+ png_warning(vi->pp, msg);
+# else
+ store_warning(vi->pp, msg);
+# endif
+ }
+
+ else /* logging this value */
+ store_verbose(&vi->dp->pm->this, vi->pp, pass, msg);
+ }
+ }
+ }
+
+ return i;
+}
+
+static void
+gamma_image_validate(gamma_display *dp, png_structp pp, png_infop pi)
+{
+ /* Get some constants derived from the input and output file formats: */
+ PNG_CONST png_store* PNG_CONST ps = dp->this.ps;
+ PNG_CONST png_byte in_ct = dp->this.colour_type;
+ PNG_CONST png_byte in_bd = dp->this.bit_depth;
+ PNG_CONST png_uint_32 w = dp->this.w;
+ PNG_CONST png_uint_32 h = dp->this.h;
+ PNG_CONST size_t cbRow = dp->this.cbRow;
+ PNG_CONST png_byte out_ct = png_get_color_type(pp, pi);
+ PNG_CONST png_byte out_bd = png_get_bit_depth(pp, pi);
+
+ /* There are three sources of error, firstly the quantization in the
+ * file encoding, determined by sbit and/or the file depth, secondly
+ * the output (screen) gamma and thirdly the output file encoding.
+ *
+ * Since this API receives the screen and file gamma in double
+ * precision it is possible to calculate an exact answer given an input
+ * pixel value. Therefore we assume that the *input* value is exact -
+ * sample/maxsample - calculate the corresponding gamma corrected
+ * output to the limits of double precision arithmetic and compare with
+ * what libpng returns.
+ *
+ * Since the library must quantize the output to 8 or 16 bits there is
+ * a fundamental limit on the accuracy of the output of +/-.5 - this
+ * quantization limit is included in addition to the other limits
+ * specified by the paramaters to the API. (Effectively, add .5
+ * everywhere.)
+ *
+ * The behavior of the 'sbit' paramter is defined by section 12.5
+ * (sample depth scaling) of the PNG spec. That section forces the
+ * decoder to assume that the PNG values have been scaled if sBIT is
+ * present:
+ *
+ * png-sample = floor( input-sample * (max-out/max-in) + .5);
+ *
+ * This means that only a subset of the possible PNG values should
+ * appear in the input. However, the spec allows the encoder to use a
+ * variety of approximations to the above and doesn't require any
+ * restriction of the values produced.
+ *
+ * Nevertheless the spec requires that the upper 'sBIT' bits of the
+ * value stored in a PNG file be the original sample bits.
+ * Consequently the code below simply scales the top sbit bits by
+ * (1<<sbit)-1 to obtain an original sample value.
+ *
+ * Because there is limited precision in the input it is arguable that
+ * an acceptable result is any valid result from input-.5 to input+.5.
+ * The basic tests below do not do this, however if 'use_input_precision'
+ * is set a subsequent test is performed below.
+ */
+ PNG_CONST unsigned int samples_per_pixel = (out_ct & 2U) ? 3U : 1U;
+ int processing;
+ png_uint_32 y;
+ PNG_CONST store_palette_entry *in_palette = dp->this.palette;
+ PNG_CONST int in_is_transparent = dp->this.is_transparent;
+ int out_npalette = -1;
+ int out_is_transparent = 0; /* Just refers to the palette case */
+ store_palette out_palette;
+ validate_info vi;
+
+ /* Check for row overwrite errors */
+ store_image_check(dp->this.ps, pp, 0);
+
+ /* Supply the input and output sample depths here - 8 for an indexed image,
+ * otherwise the bit depth.
+ */
+ init_validate_info(&vi, dp, pp, in_ct==3?8:in_bd, out_ct==3?8:out_bd);
+
+ processing = (vi.gamma_correction > 0 && !dp->threshold_test)
+ || in_bd != out_bd || in_ct != out_ct || vi.do_background;
+
+ /* TODO: FIX THIS: MAJOR BUG! If the transformations all happen inside
+ * the palette there is no way of finding out, because libpng fails to
+ * update the palette on png_read_update_info. Indeed, libpng doesn't
+ * even do the required work until much later, when it doesn't have any
+ * info pointer. Oops. For the moment 'processing' is turned off if
+ * out_ct is palette.
+ */
+ if (in_ct == 3 && out_ct == 3)
+ processing = 0;
+
+ if (processing && out_ct == 3)
+ out_is_transparent = read_palette(out_palette, &out_npalette, pp, pi);
+
+ for (y=0; y<h; ++y)
+ {
+ png_const_bytep pRow = store_image_row(ps, pp, 0, y);
+ png_byte std[STANDARD_ROWMAX];
+
+ transform_row(pp, std, in_ct, in_bd, y);
+
+ if (processing)
+ {
+ unsigned int x;
+
+ for (x=0; x<w; ++x)
+ {
+ double alpha = 1; /* serves as a flag value */
+
+ /* Record the palette index for index images. */
+ PNG_CONST unsigned int in_index =
+ in_ct == 3 ? sample(std, 3, in_bd, x, 0) : 256;
+ PNG_CONST unsigned int out_index =
+ out_ct == 3 ? sample(std, 3, out_bd, x, 0) : 256;
+
+ /* Handle input alpha - png_set_background will cause the output
+ * alpha to disappear so there is nothing to check.
+ */
+ if ((in_ct & PNG_COLOR_MASK_ALPHA) != 0 || (in_ct == 3 &&
+ in_is_transparent))
+ {
+ PNG_CONST unsigned int input_alpha = in_ct == 3 ?
+ dp->this.palette[in_index].alpha :
+ sample(std, in_ct, in_bd, x, samples_per_pixel);
+
+ unsigned int output_alpha = 65536 /* as a flag value */;
+
+ if (out_ct == 3)
+ {
+ if (out_is_transparent)
+ output_alpha = out_palette[out_index].alpha;
+ }
+
+ else if ((out_ct & PNG_COLOR_MASK_ALPHA) != 0)
+ output_alpha = sample(pRow, out_ct, out_bd, x,
+ samples_per_pixel);
+
+ if (output_alpha != 65536)
+ alpha = gamma_component_validate("alpha", &vi, input_alpha,
+ output_alpha, -1/*alpha*/, 0/*background*/);
+
+ else /* no alpha in output */
+ {
+ /* This is a copy of the calculation of 'i' above in order to
+ * have the alpha value to use in the background calculation.
+ */
+ alpha = input_alpha >> vi.isbit_shift;
+ alpha /= vi.sbit_max;
+ }
+ }
+
+ /* Handle grayscale or RGB components. */
+ if ((in_ct & PNG_COLOR_MASK_COLOR) == 0) /* grayscale */
+ (void)gamma_component_validate("gray", &vi,
+ sample(std, in_ct, in_bd, x, 0),
+ sample(pRow, out_ct, out_bd, x, 0), alpha/*component*/,
+ vi.background_red);
+ else /* RGB or palette */
+ {
+ (void)gamma_component_validate("red", &vi,
+ in_ct == 3 ? in_palette[in_index].red :
+ sample(std, in_ct, in_bd, x, 0),
+ out_ct == 3 ? out_palette[out_index].red :
+ sample(pRow, out_ct, out_bd, x, 0),
+ alpha/*component*/, vi.background_red);
+
+ (void)gamma_component_validate("green", &vi,
+ in_ct == 3 ? in_palette[in_index].green :
+ sample(std, in_ct, in_bd, x, 1),
+ out_ct == 3 ? out_palette[out_index].green :
+ sample(pRow, out_ct, out_bd, x, 1),
+ alpha/*component*/, vi.background_green);
+
+ (void)gamma_component_validate("blue", &vi,
+ in_ct == 3 ? in_palette[in_index].blue :
+ sample(std, in_ct, in_bd, x, 2),
+ out_ct == 3 ? out_palette[out_index].blue :
+ sample(pRow, out_ct, out_bd, x, 2),
+ alpha/*component*/, vi.background_blue);
+ }
+ }
+ }
+
+ else if (memcmp(std, pRow, cbRow) != 0)
+ {
+ char msg[64];
+
+ /* No transform is expected on the threshold tests. */
+ sprintf(msg, "gamma: below threshold row %d changed", y);
+
+ png_error(pp, msg);
+ }
+ } /* row (y) loop */
+
+ dp->this.ps->validated = 1;
+}
+
+static void
+gamma_end(png_structp pp, png_infop pi)
+{
+ gamma_display *dp = voidcast(gamma_display*, png_get_progressive_ptr(pp));
+
+ if (!dp->this.speed)
+ gamma_image_validate(dp, pp, pi);
+ else
+ dp->this.ps->validated = 1;
+}
+
+/* A single test run checking a gamma transformation.
+ *
+ * maxabs: maximum absolute error as a fraction
+ * maxout: maximum output error in the output units
+ * maxpc: maximum percentage error (as a percentage)
+ */
+static void
+gamma_test(png_modifier *pmIn, PNG_CONST png_byte colour_typeIn,
+ PNG_CONST png_byte bit_depthIn, PNG_CONST int palette_numberIn,
+ PNG_CONST int interlace_typeIn,
+ PNG_CONST double file_gammaIn, PNG_CONST double screen_gammaIn,
+ PNG_CONST png_byte sbitIn, PNG_CONST int threshold_testIn,
+ PNG_CONST char *name,
+ PNG_CONST int use_input_precisionIn, PNG_CONST int scale16In,
+ PNG_CONST int expand16In, PNG_CONST int do_backgroundIn,
+ PNG_CONST png_color_16 *bkgd_colorIn, double bkgd_gammaIn)
+{
+ gamma_display d;
+ context(&pmIn->this, fault);
+
+ gamma_display_init(&d, pmIn, FILEID(colour_typeIn, bit_depthIn,
+ palette_numberIn, interlace_typeIn, 0, 0, 0),
+ file_gammaIn, screen_gammaIn, sbitIn,
+ threshold_testIn, use_input_precisionIn, scale16In,
+ expand16In, do_backgroundIn, bkgd_colorIn, bkgd_gammaIn);
+
+ Try
+ {
+ png_structp pp;
+ png_infop pi;
+ gama_modification gama_mod;
+ srgb_modification srgb_mod;
+ sbit_modification sbit_mod;
+
+ /* For the moment don't use the png_modifier support here. */
+ d.pm->encoding_counter = 0;
+ modifier_set_encoding(d.pm); /* Just resets everything */
+ d.pm->current_gamma = d.file_gamma;
+
+ /* Make an appropriate modifier to set the PNG file gamma to the
+ * given gamma value and the sBIT chunk to the given precision.
+ */
+ d.pm->modifications = NULL;
+ gama_modification_init(&gama_mod, d.pm, d.file_gamma);
+ srgb_modification_init(&srgb_mod, d.pm, 127 /*delete*/);
+ if (d.sbit > 0)
+ sbit_modification_init(&sbit_mod, d.pm, d.sbit);
+
+ modification_reset(d.pm->modifications);
+
+ /* Get a png_struct for writing the image. */
+ pp = set_modifier_for_read(d.pm, &pi, d.this.id, name);
+ standard_palette_init(&d.this);
+
+ /* Introduce the correct read function. */
+ if (d.pm->this.progressive)
+ {
+ /* Share the row function with the standard implementation. */
+ png_set_progressive_read_fn(pp, &d, gamma_info, progressive_row,
+ gamma_end);
+
+ /* Now feed data into the reader until we reach the end: */
+ modifier_progressive_read(d.pm, pp, pi);
+ }
+ else
+ {
+ /* modifier_read expects a png_modifier* */
+ png_set_read_fn(pp, d.pm, modifier_read);
+
+ /* Check the header values: */
+ png_read_info(pp, pi);
+
+ /* Process the 'info' requirements. Only one image is generated */
+ gamma_info_imp(&d, pp, pi);
+
+ sequential_row(&d.this, pp, pi, -1, 0);
+
+ if (!d.this.speed)
+ gamma_image_validate(&d, pp, pi);
+ else
+ d.this.ps->validated = 1;
+ }
+
+ modifier_reset(d.pm);
+
+ if (d.pm->log && !d.threshold_test && !d.this.speed)
+ fprintf(stderr, "%d bit %s %s: max error %f (%.2g, %2g%%)\n",
+ d.this.bit_depth, colour_types[d.this.colour_type], name,
+ d.maxerrout, d.maxerrabs, 100*d.maxerrpc);
+
+ /* Log the summary values too. */
+ if (d.this.colour_type == 0 || d.this.colour_type == 4)
+ {
+ switch (d.this.bit_depth)
+ {
+ case 1:
+ break;
+
+ case 2:
+ if (d.maxerrout > d.pm->error_gray_2)
+ d.pm->error_gray_2 = d.maxerrout;
+
+ break;
+
+ case 4:
+ if (d.maxerrout > d.pm->error_gray_4)
+ d.pm->error_gray_4 = d.maxerrout;
+
+ break;
+
+ case 8:
+ if (d.maxerrout > d.pm->error_gray_8)
+ d.pm->error_gray_8 = d.maxerrout;
+
+ break;
+
+ case 16:
+ if (d.maxerrout > d.pm->error_gray_16)
+ d.pm->error_gray_16 = d.maxerrout;
+
+ break;
+
+ default:
+ png_error(pp, "bad bit depth (internal: 1)");
+ }
+ }
+
+ else if (d.this.colour_type == 2 || d.this.colour_type == 6)
+ {
+ switch (d.this.bit_depth)
+ {
+ case 8:
+
+ if (d.maxerrout > d.pm->error_color_8)
+ d.pm->error_color_8 = d.maxerrout;
+
+ break;
+
+ case 16:
+
+ if (d.maxerrout > d.pm->error_color_16)
+ d.pm->error_color_16 = d.maxerrout;
+
+ break;
+
+ default:
+ png_error(pp, "bad bit depth (internal: 2)");
+ }
+ }
+
+ else if (d.this.colour_type == 3)
+ {
+ if (d.maxerrout > d.pm->error_indexed)
+ d.pm->error_indexed = d.maxerrout;
+ }
+ }
+
+ Catch(fault)
+ modifier_reset((png_modifier*)fault);
+}
+
+static void gamma_threshold_test(png_modifier *pm, png_byte colour_type,
+ png_byte bit_depth, int interlace_type, double file_gamma,
+ double screen_gamma)
+{
+ size_t pos = 0;
+ char name[64];
+ pos = safecat(name, sizeof name, pos, "threshold ");
+ pos = safecatd(name, sizeof name, pos, file_gamma, 3);
+ pos = safecat(name, sizeof name, pos, "/");
+ pos = safecatd(name, sizeof name, pos, screen_gamma, 3);
+
+ (void)gamma_test(pm, colour_type, bit_depth, 0/*palette*/, interlace_type,
+ file_gamma, screen_gamma, 0/*sBIT*/, 1/*threshold test*/, name,
+ 0 /*no input precision*/,
+ 0 /*no scale16*/, 0 /*no expand16*/, 0 /*no background*/, 0 /*hence*/,
+ 0 /*no background gamma*/);
+}
+
+static void
+perform_gamma_threshold_tests(png_modifier *pm)
+{
+ png_byte colour_type = 0;
+ png_byte bit_depth = 0;
+ int palette_number = 0;
+
+ /* Don't test more than one instance of each palette - it's pointless, in
+ * fact this test is somewhat excessive since libpng doesn't make this
+ * decision based on colour type or bit depth!
+ */
+ while (next_format(&colour_type, &bit_depth, &palette_number))
+ if (palette_number == 0)
+ {
+ double test_gamma = 1.0;
+ while (test_gamma >= .4)
+ {
+ /* There's little point testing the interlacing vs non-interlacing,
+ * but this can be set from the command line.
+ */
+ gamma_threshold_test(pm, colour_type, bit_depth, pm->interlace_type,
+ test_gamma, 1/test_gamma);
+ test_gamma *= .95;
+ }
+
+ /* And a special test for sRGB */
+ gamma_threshold_test(pm, colour_type, bit_depth, pm->interlace_type,
+ .45455, 2.2);
+
+ if (fail(pm))
+ return;
+ }
+}
+
+static void gamma_transform_test(png_modifier *pm,
+ PNG_CONST png_byte colour_type, PNG_CONST png_byte bit_depth,
+ PNG_CONST int palette_number,
+ PNG_CONST int interlace_type, PNG_CONST double file_gamma,
+ PNG_CONST double screen_gamma, PNG_CONST png_byte sbit,
+ PNG_CONST int use_input_precision, PNG_CONST int scale16)
+{
+ size_t pos = 0;
+ char name[64];
+
+ if (sbit != bit_depth && sbit != 0)
+ {
+ pos = safecat(name, sizeof name, pos, "sbit(");
+ pos = safecatn(name, sizeof name, pos, sbit);
+ pos = safecat(name, sizeof name, pos, ") ");
+ }
+
+ else
+ pos = safecat(name, sizeof name, pos, "gamma ");
+
+ if (scale16)
+ pos = safecat(name, sizeof name, pos, "16to8 ");
+
+ pos = safecatd(name, sizeof name, pos, file_gamma, 3);
+ pos = safecat(name, sizeof name, pos, "->");
+ pos = safecatd(name, sizeof name, pos, screen_gamma, 3);
+
+ gamma_test(pm, colour_type, bit_depth, palette_number, interlace_type,
+ file_gamma, screen_gamma, sbit, 0, name, use_input_precision,
+ scale16, pm->test_gamma_expand16, 0 , 0, 0);
+}
+
+static void perform_gamma_transform_tests(png_modifier *pm)
+{
+ png_byte colour_type = 0;
+ png_byte bit_depth = 0;
+ int palette_number = 0;
+
+ while (next_format(&colour_type, &bit_depth, &palette_number))
+ {
+ unsigned int i, j;
+
+ for (i=0; i<pm->ngamma_tests; ++i) for (j=0; j<pm->ngamma_tests; ++j)
+ if (i != j)
+ {
+ gamma_transform_test(pm, colour_type, bit_depth, palette_number,
+ pm->interlace_type, 1/pm->gammas[i], pm->gammas[j], 0/*sBIT*/,
+ pm->use_input_precision, 0 /*do not scale16*/);
+
+ if (fail(pm))
+ return;
+ }
+ }
+}
+
+static void perform_gamma_sbit_tests(png_modifier *pm)
+{
+ png_byte sbit;
+
+ /* The only interesting cases are colour and grayscale, alpha is ignored here
+ * for overall speed. Only bit depths where sbit is less than the bit depth
+ * are tested.
+ */
+ for (sbit=pm->sbitlow; sbit<(1<<READ_BDHI); ++sbit)
+ {
+ png_byte colour_type, bit_depth;
+ int npalette;
+
+ colour_type = bit_depth = 0;
+ npalette = 0;
+
+ while (next_format(&colour_type, &bit_depth, &npalette))
+ if ((colour_type & PNG_COLOR_MASK_ALPHA) == 0 &&
+ ((colour_type == 3 && sbit < 8) ||
+ (colour_type != 3 && sbit < bit_depth)))
+ {
+ unsigned int i;
+
+ for (i=0; i<pm->ngamma_tests; ++i)
+ {
+ unsigned int j;
+
+ for (j=0; j<pm->ngamma_tests; ++j) if (i != j)
+ {
+ gamma_transform_test(pm, colour_type, bit_depth, npalette,
+ pm->interlace_type, 1/pm->gammas[i], pm->gammas[j],
+ sbit, pm->use_input_precision_sbit, 0 /*scale16*/);
+
+ if (fail(pm))
+ return;
+ }
+ }
+ }
+ }
+}
+
+/* Note that this requires a 16 bit source image but produces 8 bit output, so
+ * we only need the 16bit write support, but the 16 bit images are only
+ * generated if DO_16BIT is defined.
+ */
+#ifdef DO_16BIT
+static void perform_gamma_scale16_tests(png_modifier *pm)
+{
+# ifndef PNG_MAX_GAMMA_8
+# define PNG_MAX_GAMMA_8 11
+# endif
+ /* Include the alpha cases here. Note that sbit matches the internal value
+ * used by the library - otherwise we will get spurious errors from the
+ * internal sbit style approximation.
+ *
+ * The threshold test is here because otherwise the 16 to 8 conversion will
+ * proceed *without* gamma correction, and the tests above will fail (but not
+ * by much) - this could be fixed, it only appears with the -g option.
+ */
+ unsigned int i, j;
+ for (i=0; i<pm->ngamma_tests; ++i)
+ {
+ for (j=0; j<pm->ngamma_tests; ++j)
+ {
+ if (i != j &&
+ fabs(pm->gammas[j]/pm->gammas[i]-1) >= PNG_GAMMA_THRESHOLD)
+ {
+ gamma_transform_test(pm, 0, 16, 0, pm->interlace_type,
+ 1/pm->gammas[i], pm->gammas[j], PNG_MAX_GAMMA_8,
+ pm->use_input_precision_16to8, 1 /*scale16*/);
+
+ if (fail(pm))
+ return;
+
+ gamma_transform_test(pm, 2, 16, 0, pm->interlace_type,
+ 1/pm->gammas[i], pm->gammas[j], PNG_MAX_GAMMA_8,
+ pm->use_input_precision_16to8, 1 /*scale16*/);
+
+ if (fail(pm))
+ return;
+
+ gamma_transform_test(pm, 4, 16, 0, pm->interlace_type,
+ 1/pm->gammas[i], pm->gammas[j], PNG_MAX_GAMMA_8,
+ pm->use_input_precision_16to8, 1 /*scale16*/);
+
+ if (fail(pm))
+ return;
+
+ gamma_transform_test(pm, 6, 16, 0, pm->interlace_type,
+ 1/pm->gammas[i], pm->gammas[j], PNG_MAX_GAMMA_8,
+ pm->use_input_precision_16to8, 1 /*scale16*/);
+
+ if (fail(pm))
+ return;
+ }
+ }
+ }
+}
+#endif /* 16 to 8 bit conversion */
+
+#if defined PNG_READ_BACKGROUND_SUPPORTED ||\
+ defined PNG_READ_ALPHA_MODE_SUPPORTED
+static void gamma_composition_test(png_modifier *pm,
+ PNG_CONST png_byte colour_type, PNG_CONST png_byte bit_depth,
+ PNG_CONST int palette_number,
+ PNG_CONST int interlace_type, PNG_CONST double file_gamma,
+ PNG_CONST double screen_gamma,
+ PNG_CONST int use_input_precision, PNG_CONST int do_background,
+ PNG_CONST int expand_16)
+{
+ size_t pos = 0;
+ png_const_charp base;
+ double bg;
+ char name[128];
+ png_color_16 background;
+
+ /* Make up a name and get an appropriate background gamma value. */
+ switch (do_background)
+ {
+ default:
+ base = "";
+ bg = 4; /* should not be used */
+ break;
+ case PNG_BACKGROUND_GAMMA_SCREEN:
+ base = " bckg(Screen):";
+ bg = 1/screen_gamma;
+ break;
+ case PNG_BACKGROUND_GAMMA_FILE:
+ base = " bckg(File):";
+ bg = file_gamma;
+ break;
+ case PNG_BACKGROUND_GAMMA_UNIQUE:
+ base = " bckg(Unique):";
+ /* This tests the handling of a unique value, the math is such that the
+ * value tends to be <1, but is neither screen nor file (even if they
+ * match!)
+ */
+ bg = (file_gamma + screen_gamma) / 3;
+ break;
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+ case ALPHA_MODE_OFFSET + PNG_ALPHA_PNG:
+ base = " alpha(PNG)";
+ bg = 4; /* should not be used */
+ break;
+ case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD:
+ base = " alpha(Porter-Duff)";
+ bg = 4; /* should not be used */
+ break;
+ case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED:
+ base = " alpha(Optimized)";
+ bg = 4; /* should not be used */
+ break;
+ case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN:
+ base = " alpha(Broken)";
+ bg = 4; /* should not be used */
+ break;
+#endif
+ }
+
+ /* Use random background values - the background is always presented in the
+ * output space (8 or 16 bit components).
+ */
+ if (expand_16 || bit_depth == 16)
+ {
+ png_uint_32 r = random_32();
+
+ background.red = (png_uint_16)r;
+ background.green = (png_uint_16)(r >> 16);
+ r = random_32();
+ background.blue = (png_uint_16)r;
+ background.gray = (png_uint_16)(r >> 16);
+ }
+
+ else /* 8 bit colors */
+ {
+ png_uint_32 r = random_32();
+
+ background.red = (png_byte)r;
+ background.green = (png_byte)(r >> 8);
+ background.blue = (png_byte)(r >> 16);
+ background.gray = (png_byte)(r >> 24);
+ }
+
+ background.index = 193; /* rgb(193,193,193) to detect errors */
+ if (!(colour_type & PNG_COLOR_MASK_COLOR))
+ {
+ /* Grayscale input, we do not convert to RGB (TBD), so we must set the
+ * background to gray - else libpng seems to fail.
+ */
+ background.red = background.green = background.blue = background.gray;
+ }
+
+ pos = safecat(name, sizeof name, pos, "gamma ");
+ pos = safecatd(name, sizeof name, pos, file_gamma, 3);
+ pos = safecat(name, sizeof name, pos, "->");
+ pos = safecatd(name, sizeof name, pos, screen_gamma, 3);
+
+ pos = safecat(name, sizeof name, pos, base);
+ if (do_background < ALPHA_MODE_OFFSET)
+ {
+ /* Include the background color and gamma in the name: */
+ pos = safecat(name, sizeof name, pos, "(");
+ /* This assumes no expand gray->rgb - the current code won't handle that!
+ */
+ if (colour_type & PNG_COLOR_MASK_COLOR)
+ {
+ pos = safecatn(name, sizeof name, pos, background.red);
+ pos = safecat(name, sizeof name, pos, ",");
+ pos = safecatn(name, sizeof name, pos, background.green);
+ pos = safecat(name, sizeof name, pos, ",");
+ pos = safecatn(name, sizeof name, pos, background.blue);
+ }
+ else
+ pos = safecatn(name, sizeof name, pos, background.gray);
+ pos = safecat(name, sizeof name, pos, ")^");
+ pos = safecatd(name, sizeof name, pos, bg, 3);
+ }
+
+ gamma_test(pm, colour_type, bit_depth, palette_number, interlace_type,
+ file_gamma, screen_gamma, 0/*sBIT*/, 0, name, use_input_precision,
+ 0/*strip 16*/, expand_16, do_background, &background, bg);
+}
+
+
+static void
+perform_gamma_composition_tests(png_modifier *pm, int do_background,
+ int expand_16)
+{
+ png_byte colour_type = 0;
+ png_byte bit_depth = 0;
+ int palette_number = 0;
+
+ /* Skip the non-alpha cases - there is no setting of a transparency colour at
+ * present.
+ */
+ while (next_format(&colour_type, &bit_depth, &palette_number))
+ if ((colour_type & PNG_COLOR_MASK_ALPHA) != 0)
+ {
+ unsigned int i, j;
+
+ /* Don't skip the i==j case here - it's relevant. */
+ for (i=0; i<pm->ngamma_tests; ++i) for (j=0; j<pm->ngamma_tests; ++j)
+ {
+ gamma_composition_test(pm, colour_type, bit_depth, palette_number,
+ pm->interlace_type, 1/pm->gammas[i], pm->gammas[j],
+ pm->use_input_precision, do_background, expand_16);
+
+ if (fail(pm))
+ return;
+ }
+ }
+}
+#endif /* READ_BACKGROUND || READ_ALPHA_MODE */
+
+static void
+init_gamma_errors(png_modifier *pm)
+{
+ pm->error_gray_2 = pm->error_gray_4 = pm->error_gray_8 = 0;
+ pm->error_color_8 = 0;
+ pm->error_indexed = 0;
+ pm->error_gray_16 = pm->error_color_16 = 0;
+}
+
+static void
+summarize_gamma_errors(png_modifier *pm, png_const_charp who, int low_bit_depth)
+{
+ if (who)
+ printf("Gamma correction with %s:\n", who);
+
+ if (low_bit_depth)
+ {
+ printf(" 2 bit gray: %.5f\n", pm->error_gray_2);
+ printf(" 4 bit gray: %.5f\n", pm->error_gray_4);
+ printf(" 8 bit gray: %.5f\n", pm->error_gray_8);
+ printf(" 8 bit color: %.5f\n", pm->error_color_8);
+ printf(" indexed: %.5f\n", pm->error_indexed);
+ }
+
+#ifdef DO_16BIT
+ printf(" 16 bit gray: %.5f\n", pm->error_gray_16);
+ printf(" 16 bit color: %.5f\n", pm->error_color_16);
+#endif
+}
+
+static void
+perform_gamma_test(png_modifier *pm, int summary)
+{
+ /*TODO: remove this*/
+ /* Save certain values for the temporary overrides below. */
+ unsigned int calculations_use_input_precision =
+ pm->calculations_use_input_precision;
+ double maxout8 = pm->maxout8;
+
+ /* First some arbitrary no-transform tests: */
+ if (!pm->this.speed && pm->test_gamma_threshold)
+ {
+ perform_gamma_threshold_tests(pm);
+
+ if (fail(pm))
+ return;
+ }
+
+ /* Now some real transforms. */
+ if (pm->test_gamma_transform)
+ {
+ init_gamma_errors(pm);
+ /*TODO: remove this. Necessary because the current libpng
+ * implementation works in 8 bits:
+ */
+ if (pm->test_gamma_expand16)
+ pm->calculations_use_input_precision = 1;
+ perform_gamma_transform_tests(pm);
+ if (!calculations_use_input_precision)
+ pm->calculations_use_input_precision = 0;
+
+ if (summary)
+ {
+ printf("Gamma correction error summary\n\n");
+ printf("The printed value is the maximum error in the pixel values\n");
+ printf("calculated by the libpng gamma correction code. The error\n");
+ printf("is calculated as the difference between the output pixel\n");
+ printf("value (always an integer) and the ideal value from the\n");
+ printf("libpng specification (typically not an integer).\n\n");
+
+ printf("Expect this value to be less than .5 for 8 bit formats,\n");
+ printf("less than 1 for formats with fewer than 8 bits and a small\n");
+ printf("number (typically less than 5) for the 16 bit formats.\n");
+ printf("For performance reasons the value for 16 bit formats\n");
+ printf("increases when the image file includes an sBIT chunk.\n\n");
+
+ summarize_gamma_errors(pm, 0/*who*/, 1);
+ }
+ }
+
+ /* The sbit tests produce much larger errors: */
+ if (pm->test_gamma_sbit)
+ {
+ init_gamma_errors(pm);
+ perform_gamma_sbit_tests(pm);
+
+ if (summary)
+ summarize_gamma_errors(pm, "sBIT", pm->sbitlow < 8U);
+ }
+
+#ifdef DO_16BIT /* Should be READ_16BIT_SUPPORTED */
+ if (pm->test_gamma_scale16)
+ {
+ /* The 16 to 8 bit strip operations: */
+ init_gamma_errors(pm);
+ perform_gamma_scale16_tests(pm);
+
+ if (summary)
+ {
+ printf("Gamma correction with 16 to 8 bit reduction:\n");
+ printf(" 16 bit gray: %.5f\n", pm->error_gray_16);
+ printf(" 16 bit color: %.5f\n", pm->error_color_16);
+ }
+ }
+#endif
+
+#ifdef PNG_READ_BACKGROUND_SUPPORTED
+ if (pm->test_gamma_background)
+ {
+ init_gamma_errors(pm);
+
+ /*TODO: remove this. Necessary because the current libpng
+ * implementation works in 8 bits:
+ */
+ if (pm->test_gamma_expand16)
+ {
+ pm->calculations_use_input_precision = 1;
+ pm->maxout8 = .499; /* because the 16 bit background is smashed */
+ }
+ perform_gamma_composition_tests(pm, PNG_BACKGROUND_GAMMA_UNIQUE,
+ pm->test_gamma_expand16);
+ if (!calculations_use_input_precision)
+ pm->calculations_use_input_precision = 0;
+ pm->maxout8 = maxout8;
+
+ if (summary)
+ summarize_gamma_errors(pm, "background", 1);
+ }
+#endif
+
+#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
+ if (pm->test_gamma_alpha_mode)
+ {
+ int do_background;
+
+ init_gamma_errors(pm);
+
+ /*TODO: remove this. Necessary because the current libpng
+ * implementation works in 8 bits:
+ */
+ if (pm->test_gamma_expand16)
+ pm->calculations_use_input_precision = 1;
+ for (do_background = ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD;
+ do_background <= ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN && !fail(pm);
+ ++do_background)
+ perform_gamma_composition_tests(pm, do_background,
+ pm->test_gamma_expand16);
+ if (!calculations_use_input_precision)
+ pm->calculations_use_input_precision = 0;
+
+ if (summary)
+ summarize_gamma_errors(pm, "alpha mode", 1);
+ }
+#endif
+}
+#endif /* PNG_READ_GAMMA_SUPPORTED */
+
+/* INTERLACE MACRO VALIDATION */
+/* This is copied verbatim from the specification, it is simply the pass
+ * number in which each pixel in each 8x8 tile appears. The array must
+ * be indexed adam7[y][x] and notice that the pass numbers are based at
+ * 1, not 0 - the base libpng uses.
+ */
+static PNG_CONST
+png_byte adam7[8][8] =
+{
+ { 1,6,4,6,2,6,4,6 },
+ { 7,7,7,7,7,7,7,7 },
+ { 5,6,5,6,5,6,5,6 },
+ { 7,7,7,7,7,7,7,7 },
+ { 3,6,4,6,3,6,4,6 },
+ { 7,7,7,7,7,7,7,7 },
+ { 5,6,5,6,5,6,5,6 },
+ { 7,7,7,7,7,7,7,7 }
+};
+
+/* This routine validates all the interlace support macros in png.h for
+ * a variety of valid PNG widths and heights. It uses a number of similarly
+ * named internal routines that feed off the above array.
+ */
+static png_uint_32
+png_pass_start_row(int pass)
+{
+ int x, y;
+ ++pass;
+ for (y=0; y<8; ++y) for (x=0; x<8; ++x) if (adam7[y][x] == pass)
+ return y;
+ return 0xf;
+}
+
+static png_uint_32
+png_pass_start_col(int pass)
+{
+ int x, y;
+ ++pass;
+ for (x=0; x<8; ++x) for (y=0; y<8; ++y) if (adam7[y][x] == pass)
+ return x;
+ return 0xf;
+}
+
+static int
+png_pass_row_shift(int pass)
+{
+ int x, y, base=(-1), inc=8;
+ ++pass;
+ for (y=0; y<8; ++y) for (x=0; x<8; ++x) if (adam7[y][x] == pass)
+ {
+ if (base == (-1))
+ base = y;
+ else if (base == y)
+ {}
+ else if (inc == y-base)
+ base=y;
+ else if (inc == 8)
+ inc = y-base, base=y;
+ else if (inc != y-base)
+ return 0xff; /* error - more than one 'inc' value! */
+ }
+
+ if (base == (-1)) return 0xfe; /* error - no row in pass! */
+
+ /* The shift is always 1, 2 or 3 - no pass has all the rows! */
+ switch (inc)
+ {
+case 2: return 1;
+case 4: return 2;
+case 8: return 3;
+default: break;
+ }
+
+ /* error - unrecognized 'inc' */
+ return (inc << 8) + 0xfd;
+}
+
+static int
+png_pass_col_shift(int pass)
+{
+ int x, y, base=(-1), inc=8;
+ ++pass;
+ for (x=0; x<8; ++x) for (y=0; y<8; ++y) if (adam7[y][x] == pass)
+ {
+ if (base == (-1))
+ base = x;
+ else if (base == x)
+ {}
+ else if (inc == x-base)
+ base=x;
+ else if (inc == 8)
+ inc = x-base, base=x;
+ else if (inc != x-base)
+ return 0xff; /* error - more than one 'inc' value! */
+ }
+
+ if (base == (-1)) return 0xfe; /* error - no row in pass! */
+
+ /* The shift is always 1, 2 or 3 - no pass has all the rows! */
+ switch (inc)
+ {
+case 1: return 0; /* pass 7 has all the columns */
+case 2: return 1;
+case 4: return 2;
+case 8: return 3;
+default: break;
+ }
+
+ /* error - unrecognized 'inc' */
+ return (inc << 8) + 0xfd;
+}
+
+static png_uint_32
+png_row_from_pass_row(png_uint_32 yIn, int pass)
+{
+ /* By examination of the array: */
+ switch (pass)
+ {
+case 0: return yIn * 8;
+case 1: return yIn * 8;
+case 2: return yIn * 8 + 4;
+case 3: return yIn * 4;
+case 4: return yIn * 4 + 2;
+case 5: return yIn * 2;
+case 6: return yIn * 2 + 1;
+default: break;
+ }
+
+ return 0xff; /* bad pass number */
+}
+
+static png_uint_32
+png_col_from_pass_col(png_uint_32 xIn, int pass)
+{
+ /* By examination of the array: */
+ switch (pass)
+ {
+case 0: return xIn * 8;
+case 1: return xIn * 8 + 4;
+case 2: return xIn * 4;
+case 3: return xIn * 4 + 2;
+case 4: return xIn * 2;
+case 5: return xIn * 2 + 1;
+case 6: return xIn;
+default: break;
+ }
+
+ return 0xff; /* bad pass number */
+}
+
+static int
+png_row_in_interlace_pass(png_uint_32 y, int pass)
+{
+ /* Is row 'y' in pass 'pass'? */
+ int x;
+ y &= 7;
+ ++pass;
+ for (x=0; x<8; ++x) if (adam7[y][x] == pass)
+ return 1;
+
+ return 0;
+}
+
+static int
+png_col_in_interlace_pass(png_uint_32 x, int pass)
+{
+ /* Is column 'x' in pass 'pass'? */
+ int y;
+ x &= 7;
+ ++pass;
+ for (y=0; y<8; ++y) if (adam7[y][x] == pass)
+ return 1;
+
+ return 0;
+}
+
+static png_uint_32
+png_pass_rows(png_uint_32 height, int pass)
+{
+ png_uint_32 tiles = height>>3;
+ png_uint_32 rows = 0;
+ unsigned int x, y;
+
+ height &= 7;
+ ++pass;
+ for (y=0; y<8; ++y) for (x=0; x<8; ++x) if (adam7[y][x] == pass)
+ {
+ rows += tiles;
+ if (y < height) ++rows;
+ break; /* i.e. break the 'x', column, loop. */
+ }
+
+ return rows;
+}
+
+static png_uint_32
+png_pass_cols(png_uint_32 width, int pass)
+{
+ png_uint_32 tiles = width>>3;
+ png_uint_32 cols = 0;
+ unsigned int x, y;
+
+ width &= 7;
+ ++pass;
+ for (x=0; x<8; ++x) for (y=0; y<8; ++y) if (adam7[y][x] == pass)
+ {
+ cols += tiles;
+ if (x < width) ++cols;
+ break; /* i.e. break the 'y', row, loop. */
+ }
+
+ return cols;
+}
+
+static void
+perform_interlace_macro_validation(void)
+{
+ /* The macros to validate, first those that depend only on pass:
+ *
+ * PNG_PASS_START_ROW(pass)
+ * PNG_PASS_START_COL(pass)
+ * PNG_PASS_ROW_SHIFT(pass)
+ * PNG_PASS_COL_SHIFT(pass)
+ */
+ int pass;
+
+ for (pass=0; pass<7; ++pass)
+ {
+ png_uint_32 m, f, v;
+
+ m = PNG_PASS_START_ROW(pass);
+ f = png_pass_start_row(pass);
+ if (m != f)
+ {
+ fprintf(stderr, "PNG_PASS_START_ROW(%d) = %u != %x\n", pass, m, f);
+ exit(1);
+ }
+
+ m = PNG_PASS_START_COL(pass);
+ f = png_pass_start_col(pass);
+ if (m != f)
+ {
+ fprintf(stderr, "PNG_PASS_START_COL(%d) = %u != %x\n", pass, m, f);
+ exit(1);
+ }
+
+ m = PNG_PASS_ROW_SHIFT(pass);
+ f = png_pass_row_shift(pass);
+ if (m != f)
+ {
+ fprintf(stderr, "PNG_PASS_ROW_SHIFT(%d) = %u != %x\n", pass, m, f);
+ exit(1);
+ }
+
+ m = PNG_PASS_COL_SHIFT(pass);
+ f = png_pass_col_shift(pass);
+ if (m != f)
+ {
+ fprintf(stderr, "PNG_PASS_COL_SHIFT(%d) = %u != %x\n", pass, m, f);
+ exit(1);
+ }
+
+ /* Macros that depend on the image or sub-image height too:
+ *
+ * PNG_PASS_ROWS(height, pass)
+ * PNG_PASS_COLS(width, pass)
+ * PNG_ROW_FROM_PASS_ROW(yIn, pass)
+ * PNG_COL_FROM_PASS_COL(xIn, pass)
+ * PNG_ROW_IN_INTERLACE_PASS(y, pass)
+ * PNG_COL_IN_INTERLACE_PASS(x, pass)
+ */
+ for (v=0;;)
+ {
+ /* First the base 0 stuff: */
+ m = PNG_ROW_FROM_PASS_ROW(v, pass);
+ f = png_row_from_pass_row(v, pass);
+ if (m != f)
+ {
+ fprintf(stderr, "PNG_ROW_FROM_PASS_ROW(%u, %d) = %u != %x\n",
+ v, pass, m, f);
+ exit(1);
+ }
+
+ m = PNG_COL_FROM_PASS_COL(v, pass);
+ f = png_col_from_pass_col(v, pass);
+ if (m != f)
+ {
+ fprintf(stderr, "PNG_COL_FROM_PASS_COL(%u, %d) = %u != %x\n",
+ v, pass, m, f);
+ exit(1);
+ }
+
+ m = PNG_ROW_IN_INTERLACE_PASS(v, pass);
+ f = png_row_in_interlace_pass(v, pass);
+ if (m != f)
+ {
+ fprintf(stderr, "PNG_ROW_IN_INTERLACE_PASS(%u, %d) = %u != %x\n",
+ v, pass, m, f);
+ exit(1);
+ }
+
+ m = PNG_COL_IN_INTERLACE_PASS(v, pass);
+ f = png_col_in_interlace_pass(v, pass);
+ if (m != f)
+ {
+ fprintf(stderr, "PNG_COL_IN_INTERLACE_PASS(%u, %d) = %u != %x\n",
+ v, pass, m, f);
+ exit(1);
+ }
+
+ /* Then the base 1 stuff: */
+ ++v;
+ m = PNG_PASS_ROWS(v, pass);
+ f = png_pass_rows(v, pass);
+ if (m != f)
+ {
+ fprintf(stderr, "PNG_PASS_ROWS(%u, %d) = %u != %x\n",
+ v, pass, m, f);
+ exit(1);
+ }
+
+ m = PNG_PASS_COLS(v, pass);
+ f = png_pass_cols(v, pass);
+ if (m != f)
+ {
+ fprintf(stderr, "PNG_PASS_COLS(%u, %d) = %u != %x\n",
+ v, pass, m, f);
+ exit(1);
+ }
+
+ /* Move to the next v - the stepping algorithm starts skipping
+ * values above 1024.
+ */
+ if (v > 1024)
+ {
+ if (v == PNG_UINT_31_MAX)
+ break;
+
+ v = (v << 1) ^ v;
+ if (v >= PNG_UINT_31_MAX)
+ v = PNG_UINT_31_MAX-1;
+ }
+ }
+ }
+}
+
+/* Test color encodings. These values are back-calculated from the published
+ * chromaticities. The values are accurate to about 14 decimal places; 15 are
+ * given. These values are much more accurate than the ones given in the spec,
+ * which typically don't exceed 4 decimal places. This allows testing of the
+ * libpng code to its theoretical accuracy of 4 decimal places. (If pngvalid
+ * used the published errors the 'slack' permitted would have to be +/-.5E-4 or
+ * more.)
+ *
+ * The png_modifier code assumes that encodings[0] is sRGB and treats it
+ * specially: do not change the first entry in this list!
+ */
+static PNG_CONST color_encoding test_encodings[] =
+{
+/* sRGB: must be first in this list! */
+/*gamma:*/ { 1/2.2,
+/*red: */ { 0.412390799265959, 0.212639005871510, 0.019330818715592 },
+/*green:*/ { 0.357584339383878, 0.715168678767756, 0.119194779794626 },
+/*blue: */ { 0.180480788401834, 0.072192315360734, 0.950532152249660} },
+/* Kodak ProPhoto (wide gamut) */
+/*gamma:*/ { 1/1.6 /*approximate: uses 1.8 power law compared to sRGB 2.4*/,
+/*red: */ { 0.797760489672303, 0.288071128229293, 0.000000000000000 },
+/*green:*/ { 0.135185837175740, 0.711843217810102, 0.000000000000000 },
+/*blue: */ { 0.031349349581525, 0.000085653960605, 0.825104602510460} },
+/* Adobe RGB (1998) */
+/*gamma:*/ { 1/(2+51./256),
+/*red: */ { 0.576669042910131, 0.297344975250536, 0.027031361386412 },
+/*green:*/ { 0.185558237906546, 0.627363566255466, 0.070688852535827 },
+/*blue: */ { 0.188228646234995, 0.075291458493998, 0.991337536837639} },
+/* Adobe Wide Gamut RGB */
+/*gamma:*/ { 1/(2+51./256),
+/*red: */ { 0.716500716779386, 0.258728243040113, 0.000000000000000 },
+/*green:*/ { 0.101020574397477, 0.724682314948566, 0.051211818965388 },
+/*blue: */ { 0.146774385252705, 0.016589442011321, 0.773892783545073} },
+};
+
+/* signal handler
+ *
+ * This attempts to trap signals and escape without crashing. It needs a
+ * context pointer so that it can throw an exception (call longjmp) to recover
+ * from the condition; this is handled by making the png_modifier used by 'main'
+ * into a global variable.
+ */
+static png_modifier pm;
+
+static void signal_handler(int signum)
+{
+
+ size_t pos = 0;
+ char msg[64];
+
+ pos = safecat(msg, sizeof msg, pos, "caught signal: ");
+
+ switch (signum)
+ {
+ case SIGABRT:
+ pos = safecat(msg, sizeof msg, pos, "abort");
+ break;
+
+ case SIGFPE:
+ pos = safecat(msg, sizeof msg, pos, "floating point exception");
+ break;
+
+ case SIGILL:
+ pos = safecat(msg, sizeof msg, pos, "illegal instruction");
+ break;
+
+ case SIGINT:
+ pos = safecat(msg, sizeof msg, pos, "interrupt");
+ break;
+
+ case SIGSEGV:
+ pos = safecat(msg, sizeof msg, pos, "invalid memory access");
+ break;
+
+ case SIGTERM:
+ pos = safecat(msg, sizeof msg, pos, "termination request");
+ break;
+
+ default:
+ pos = safecat(msg, sizeof msg, pos, "unknown ");
+ pos = safecatn(msg, sizeof msg, pos, signum);
+ break;
+ }
+
+ store_log(&pm.this, NULL/*png_structp*/, msg, 1/*error*/);
+
+ /* And finally throw an exception so we can keep going, unless this is
+ * SIGTERM in which case stop now.
+ */
+ if (signum != SIGTERM)
+ {
+ struct exception_context *the_exception_context =
+ &pm.this.exception_context;
+
+ Throw &pm.this;
+ }
+
+ else
+ exit(1);
+}
+
+/* main program */
+int main(int argc, PNG_CONST char **argv)
+{
+ volatile int summary = 1; /* Print the error summary at the end */
+ volatile int memstats = 0; /* Print memory statistics at the end */
+
+ /* Create the given output file on success: */
+ PNG_CONST char *volatile touch = NULL;
+
+ /* This is an array of standard gamma values (believe it or not I've seen
+ * every one of these mentioned somewhere.)
+ *
+ * In the following list the most useful values are first!
+ */
+ static double
+ gammas[]={2.2, 1.0, 2.2/1.45, 1.8, 1.5, 2.4, 2.5, 2.62, 2.9};
+
+ /* This records the command and arguments: */
+ size_t cp = 0;
+ char command[1024];
+
+ anon_context(&pm.this);
+
+ /* Add appropriate signal handlers, just the ANSI specified ones: */
+ signal(SIGABRT, signal_handler);
+ signal(SIGFPE, signal_handler);
+ signal(SIGILL, signal_handler);
+ signal(SIGINT, signal_handler);
+ signal(SIGSEGV, signal_handler);
+ signal(SIGTERM, signal_handler);
+
+#ifdef HAVE_FEENABLEEXCEPT
+ /* Only required to enable FP exceptions on platforms where they start off
+ * disabled; this is not necessary but if it is not done pngvalid will likely
+ * end up ignoring FP conditions that other platforms fault.
+ */
+ feenableexcept(FE_DIVBYZERO | FE_INVALID | FE_OVERFLOW);
+#endif
+
+ modifier_init(&pm);
+
+ /* Preallocate the image buffer, because we know how big it needs to be,
+ * note that, for testing purposes, it is deliberately mis-aligned by tag
+ * bytes either side. All rows have an additional five bytes of padding for
+ * overwrite checking.
+ */
+ store_ensure_image(&pm.this, NULL, 2, TRANSFORM_ROWMAX, TRANSFORM_HEIGHTMAX);
+
+ /* Don't give argv[0], it's normally some horrible libtool string: */
+ cp = safecat(command, sizeof command, cp, "pngvalid");
+
+ /* Default to error on warning: */
+ pm.this.treat_warnings_as_errors = 1;
+
+ /* Store the test gammas */
+ pm.gammas = gammas;
+ pm.ngammas = (sizeof gammas) / (sizeof gammas[0]);
+ pm.ngamma_tests = 0; /* default to off */
+
+ /* And the test encodings */
+ pm.encodings = test_encodings;
+ pm.nencodings = (sizeof test_encodings) / (sizeof test_encodings[0]);
+
+ pm.sbitlow = 8U; /* because libpng doesn't do sBIT below 8! */
+ /* The following allows results to pass if they correspond to anything in the
+ * transformed range [input-.5,input+.5]; this is is required because of the
+ * way libpng treates the 16_TO_8 flag when building the gamma tables.
+ *
+ * TODO: review this
+ */
+ pm.use_input_precision_16to8 = 1U;
+
+ /* Some default values (set the behavior for 'make check' here).
+ * These values simply control the maximum error permitted in the gamma
+ * transformations. The practial limits for human perception are described
+ * below (the setting for maxpc16), however for 8 bit encodings it isn't
+ * possible to meet the accepted capabilities of human vision - i.e. 8 bit
+ * images can never be good enough, regardless of encoding.
+ */
+ pm.maxout8 = .1; /* Arithmetic error in *encoded* value */
+ pm.maxabs8 = .00005; /* 1/20000 */
+ pm.maxcalc8 = .004; /* +/-1 in 8 bits for compose errors */
+ pm.maxpc8 = .499; /* I.e., .499% fractional error */
+ pm.maxout16 = .499; /* Error in *encoded* value */
+ pm.maxabs16 = .00005;/* 1/20000 */
+ pm.maxcalc16 =.000015;/* +/-1 in 16 bits for compose errors */
+
+ /* NOTE: this is a reasonable perceptual limit. We assume that humans can
+ * perceive light level differences of 1% over a 100:1 range, so we need to
+ * maintain 1 in 10000 accuracy (in linear light space), which is what the
+ * following guarantees. It also allows significantly higher errors at
+ * higher 16 bit values, which is important for performance. The actual
+ * maximum 16 bit error is about +/-1.9 in the fixed point implementation but
+ * this is only allowed for values >38149 by the following:
+ */
+ pm.maxpc16 = .005; /* I.e., 1/200% - 1/20000 */
+
+ /* Now parse the command line options. */
+ while (--argc >= 1)
+ {
+ int catmore = 0; /* Set if the argument has an argument. */
+
+ /* Record each argument for posterity: */
+ cp = safecat(command, sizeof command, cp, " ");
+ cp = safecat(command, sizeof command, cp, *++argv);
+
+ if (strcmp(*argv, "-v") == 0)
+ pm.this.verbose = 1;
+
+ else if (strcmp(*argv, "-l") == 0)
+ pm.log = 1;
+
+ else if (strcmp(*argv, "-q") == 0)
+ summary = pm.this.verbose = pm.log = 0;
+
+ else if (strcmp(*argv, "-w") == 0)
+ pm.this.treat_warnings_as_errors = 0;
+
+ else if (strcmp(*argv, "--speed") == 0)
+ pm.this.speed = 1, pm.ngamma_tests = pm.ngammas, pm.test_standard = 0,
+ summary = 0;
+
+ else if (strcmp(*argv, "--memory") == 0)
+ memstats = 1;
+
+ else if (strcmp(*argv, "--size") == 0)
+ pm.test_size = 1;
+
+ else if (strcmp(*argv, "--nosize") == 0)
+ pm.test_size = 0;
+
+ else if (strcmp(*argv, "--standard") == 0)
+ pm.test_standard = 1;
+
+ else if (strcmp(*argv, "--nostandard") == 0)
+ pm.test_standard = 0;
+
+ else if (strcmp(*argv, "--transform") == 0)
+ pm.test_transform = 1;
+
+ else if (strcmp(*argv, "--notransform") == 0)
+ pm.test_transform = 0;
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+ else if (strncmp(*argv, "--transform-disable=",
+ sizeof "--transform-disable") == 0)
+ {
+ pm.test_transform = 1;
+ transform_disable(*argv + sizeof "--transform-disable");
+ }
+
+ else if (strncmp(*argv, "--transform-enable=",
+ sizeof "--transform-enable") == 0)
+ {
+ pm.test_transform = 1;
+ transform_enable(*argv + sizeof "--transform-enable");
+ }
+#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
+
+ else if (strcmp(*argv, "--gamma") == 0)
+ {
+ /* Just do two gamma tests here (2.2 and linear) for speed: */
+ pm.ngamma_tests = 2U;
+ pm.test_gamma_threshold = 1;
+ pm.test_gamma_transform = 1;
+ pm.test_gamma_sbit = 1;
+ pm.test_gamma_scale16 = 1;
+ pm.test_gamma_background = 1;
+ pm.test_gamma_alpha_mode = 1;
+ }
+
+ else if (strcmp(*argv, "--nogamma") == 0)
+ pm.ngamma_tests = 0;
+
+ else if (strcmp(*argv, "--gamma-threshold") == 0)
+ pm.ngamma_tests = 2U, pm.test_gamma_threshold = 1;
+
+ else if (strcmp(*argv, "--nogamma-threshold") == 0)
+ pm.test_gamma_threshold = 0;
+
+ else if (strcmp(*argv, "--gamma-transform") == 0)
+ pm.ngamma_tests = 2U, pm.test_gamma_transform = 1;
+
+ else if (strcmp(*argv, "--nogamma-transform") == 0)
+ pm.test_gamma_transform = 0;
+
+ else if (strcmp(*argv, "--gamma-sbit") == 0)
+ pm.ngamma_tests = 2U, pm.test_gamma_sbit = 1;
+
+ else if (strcmp(*argv, "--nogamma-sbit") == 0)
+ pm.test_gamma_sbit = 0;
+
+ else if (strcmp(*argv, "--gamma-16-to-8") == 0)
+ pm.ngamma_tests = 2U, pm.test_gamma_scale16 = 1;
+
+ else if (strcmp(*argv, "--nogamma-16-to-8") == 0)
+ pm.test_gamma_scale16 = 0;
+
+ else if (strcmp(*argv, "--gamma-background") == 0)
+ pm.ngamma_tests = 2U, pm.test_gamma_background = 1;
+
+ else if (strcmp(*argv, "--nogamma-background") == 0)
+ pm.test_gamma_background = 0;
+
+ else if (strcmp(*argv, "--gamma-alpha-mode") == 0)
+ pm.ngamma_tests = 2U, pm.test_gamma_alpha_mode = 1;
+
+ else if (strcmp(*argv, "--nogamma-alpha-mode") == 0)
+ pm.test_gamma_alpha_mode = 0;
+
+ else if (strcmp(*argv, "--expand16") == 0)
+ pm.test_gamma_expand16 = 1;
+
+ else if (strcmp(*argv, "--noexpand16") == 0)
+ pm.test_gamma_expand16 = 0;
+
+ else if (strcmp(*argv, "--more-gammas") == 0)
+ pm.ngamma_tests = 3U;
+
+ else if (strcmp(*argv, "--all-gammas") == 0)
+ pm.ngamma_tests = pm.ngammas;
+
+ else if (strcmp(*argv, "--progressive-read") == 0)
+ pm.this.progressive = 1;
+
+ else if (strcmp(*argv, "--use-update-info") == 0)
+ ++pm.use_update_info; /* Can call multiple times */
+
+ else if (strcmp(*argv, "--interlace") == 0)
+ pm.interlace_type = PNG_INTERLACE_ADAM7;
+
+ else if (strcmp(*argv, "--use-input-precision") == 0)
+ pm.use_input_precision = 1;
+
+ else if (strcmp(*argv, "--calculations-use-input-precision") == 0)
+ pm.calculations_use_input_precision = 1;
+
+ else if (strcmp(*argv, "--assume-16-bit-calculations") == 0)
+ pm.assume_16_bit_calculations = 1;
+
+ else if (strcmp(*argv, "--calculations-follow-bit-depth") == 0)
+ pm.calculations_use_input_precision =
+ pm.assume_16_bit_calculations = 0;
+
+ else if (strcmp(*argv, "--exhaustive") == 0)
+ pm.test_exhaustive = 1;
+
+ else if (argc > 1 && strcmp(*argv, "--sbitlow") == 0)
+ --argc, pm.sbitlow = (png_byte)atoi(*++argv), catmore = 1;
+
+ else if (argc > 1 && strcmp(*argv, "--touch") == 0)
+ --argc, touch = *++argv, catmore = 1;
+
+ else if (argc > 1 && strncmp(*argv, "--max", 5) == 0)
+ {
+ --argc;
+
+ if (strcmp(5+*argv, "abs8") == 0)
+ pm.maxabs8 = atof(*++argv);
+
+ else if (strcmp(5+*argv, "abs16") == 0)
+ pm.maxabs16 = atof(*++argv);
+
+ else if (strcmp(5+*argv, "calc8") == 0)
+ pm.maxcalc8 = atof(*++argv);
+
+ else if (strcmp(5+*argv, "calc16") == 0)
+ pm.maxcalc16 = atof(*++argv);
+
+ else if (strcmp(5+*argv, "out8") == 0)
+ pm.maxout8 = atof(*++argv);
+
+ else if (strcmp(5+*argv, "out16") == 0)
+ pm.maxout16 = atof(*++argv);
+
+ else if (strcmp(5+*argv, "pc8") == 0)
+ pm.maxpc8 = atof(*++argv);
+
+ else if (strcmp(5+*argv, "pc16") == 0)
+ pm.maxpc16 = atof(*++argv);
+
+ else
+ {
+ fprintf(stderr, "pngvalid: %s: unknown 'max' option\n", *argv);
+ exit(1);
+ }
+
+ catmore = 1;
+ }
+
+ else if (strcmp(*argv, "--log8") == 0)
+ --argc, pm.log8 = atof(*++argv), catmore = 1;
+
+ else if (strcmp(*argv, "--log16") == 0)
+ --argc, pm.log16 = atof(*++argv), catmore = 1;
+
+ else
+ {
+ fprintf(stderr, "pngvalid: %s: unknown argument\n", *argv);
+ exit(1);
+ }
+
+ if (catmore) /* consumed an extra *argv */
+ {
+ cp = safecat(command, sizeof command, cp, " ");
+ cp = safecat(command, sizeof command, cp, *argv);
+ }
+ }
+
+ /* If pngvalid is run with no arguments default to a reasonable set of the
+ * tests.
+ */
+ if (pm.test_standard == 0 && pm.test_size == 0 && pm.test_transform == 0 &&
+ pm.ngamma_tests == 0)
+ {
+ /* Make this do all the tests done in the test shell scripts with the same
+ * parameters, where possible. The limitation is that all the progressive
+ * read and interlace stuff has to be done in separate runs, so only the
+ * basic 'standard' and 'size' tests are done.
+ */
+ pm.test_standard = 1;
+ pm.test_size = 1;
+ pm.test_transform = 1;
+ pm.ngamma_tests = 2U;
+ }
+
+ if (pm.ngamma_tests > 0 &&
+ pm.test_gamma_threshold == 0 && pm.test_gamma_transform == 0 &&
+ pm.test_gamma_sbit == 0 && pm.test_gamma_scale16 == 0 &&
+ pm.test_gamma_background == 0 && pm.test_gamma_alpha_mode == 0)
+ {
+ pm.test_gamma_threshold = 1;
+ pm.test_gamma_transform = 1;
+ pm.test_gamma_sbit = 1;
+ pm.test_gamma_scale16 = 1;
+ pm.test_gamma_background = 1;
+ pm.test_gamma_alpha_mode = 1;
+ }
+
+ else if (pm.ngamma_tests == 0)
+ {
+ /* Nothing to test so turn everything off: */
+ pm.test_gamma_threshold = 0;
+ pm.test_gamma_transform = 0;
+ pm.test_gamma_sbit = 0;
+ pm.test_gamma_scale16 = 0;
+ pm.test_gamma_background = 0;
+ pm.test_gamma_alpha_mode = 0;
+ }
+
+ Try
+ {
+ /* Make useful base images */
+ make_transform_images(&pm.this);
+
+ /* Perform the standard and gamma tests. */
+ if (pm.test_standard)
+ {
+ perform_interlace_macro_validation();
+ perform_formatting_test(&pm.this);
+ perform_standard_test(&pm);
+ perform_error_test(&pm);
+ }
+
+ /* Various oddly sized images: */
+ if (pm.test_size)
+ {
+ make_size_images(&pm.this);
+ perform_size_test(&pm);
+ }
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+ /* Combinatorial transforms: */
+ if (pm.test_transform)
+ perform_transform_test(&pm);
+#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
+
+#ifdef PNG_READ_GAMMA_SUPPORTED
+ if (pm.ngamma_tests > 0)
+ perform_gamma_test(&pm, summary);
+#endif
+ }
+
+ Catch_anonymous
+ {
+ fprintf(stderr, "pngvalid: test aborted (probably failed in cleanup)\n");
+ if (!pm.this.verbose)
+ {
+ if (pm.this.error[0] != 0)
+ fprintf(stderr, "pngvalid: first error: %s\n", pm.this.error);
+
+ fprintf(stderr, "pngvalid: run with -v to see what happened\n");
+ }
+ exit(1);
+ }
+
+ if (summary)
+ {
+ printf("%s: %s (%s point arithmetic)\n",
+ (pm.this.nerrors || (pm.this.treat_warnings_as_errors &&
+ pm.this.nwarnings)) ? "FAIL" : "PASS",
+ command,
+#if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || PNG_LIBPNG_VER < 10500
+ "floating"
+#else
+ "fixed"
+#endif
+ );
+ }
+
+ if (memstats)
+ {
+ printf("Allocated memory statistics (in bytes):\n"
+ "\tread %lu maximum single, %lu peak, %lu total\n"
+ "\twrite %lu maximum single, %lu peak, %lu total\n",
+ (unsigned long)pm.this.read_memory_pool.max_max,
+ (unsigned long)pm.this.read_memory_pool.max_limit,
+ (unsigned long)pm.this.read_memory_pool.max_total,
+ (unsigned long)pm.this.write_memory_pool.max_max,
+ (unsigned long)pm.this.write_memory_pool.max_limit,
+ (unsigned long)pm.this.write_memory_pool.max_total);
+ }
+
+ /* Do this here to provoke memory corruption errors in memory not directly
+ * allocated by libpng - not a complete test, but better than nothing.
+ */
+ store_delete(&pm.this);
+
+ /* Error exit if there are any errors, and maybe if there are any
+ * warnings.
+ */
+ if (pm.this.nerrors || (pm.this.treat_warnings_as_errors &&
+ pm.this.nwarnings))
+ {
+ if (!pm.this.verbose)
+ fprintf(stderr, "pngvalid: %s\n", pm.this.error);
+
+ fprintf(stderr, "pngvalid: %d errors, %d warnings\n", pm.this.nerrors,
+ pm.this.nwarnings);
+
+ exit(1);
+ }
+
+ /* Success case. */
+ if (touch != NULL)
+ {
+ FILE *fsuccess = fopen(touch, "wt");
+
+ if (fsuccess != NULL)
+ {
+ int error = 0;
+ fprintf(fsuccess, "PNG validation succeeded\n");
+ fflush(fsuccess);
+ error = ferror(fsuccess);
+
+ if (fclose(fsuccess) || error)
+ {
+ fprintf(stderr, "%s: write failed\n", touch);
+ exit(1);
+ }
+ }
+ }
+
+ return 0;
+}
diff -ru4NwbB libpng-1.5.6/example.c libpng-1.5.7/example.c
--- libpng-1.5.6/example.c 2011-11-02 22:42:50.387042477 -0500
+++ libpng-1.5.7/example.c 2011-12-15 09:45:32.458918758 -0600
@@ -1,20 +1,21 @@
#if 0 /* in case someone actually tries to compile this */
/* example.c - an example of using libpng
- * Last changed in libpng 1.5.6 [December 15, 2011]
- * This file has been placed in the public domain by the authors.
+ * Last changed in libpng 1.5.7 [December 15, 2011]
* Maintained 1998-2011 Glenn Randers-Pehrson
- * Maintained 1996, 1997 Andreas Dilger)
- * Written 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ * Maintained 1996, 1997 Andreas Dilger
+ * Written 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
*/
/* This is an example of how to use libpng to read and write PNG files.
* The file libpng-manual.txt is much more verbose then this. If you have not
* read it, do so first. This was designed to be a starting point of an
* implementation. This is not officially part of libpng, is hereby placed
* in the public domain, and therefore does not require a copyright notice.
+ * To the extent possible under law, the authors have waived all copyright and
+ * related or neighboring rights to this file.
*
* This file does not currently compile, because it is missing certain
* parts, like allocating memory to hold an image. You will have to
* supply these parts to get it to compile. For an example of a minimal
diff -ru4NwbB libpng-1.5.6/png.c libpng-1.5.7/png.c
--- libpng-1.5.6/png.c 2011-11-02 22:42:50.399590772 -0500
+++ libpng-1.5.7/png.c 2011-12-15 09:45:32.471948179 -0600
@@ -1,8 +1,8 @@
/* png.c - location for general purpose libpng functions
*
- * Last changed in libpng 1.5.6 [December 15, 2011]
+ * Last changed in libpng 1.5.7 [December 15, 2011]
* Copyright (c) 1998-2011 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
*
@@ -598,11 +598,21 @@
if (png_ptr == NULL)
return (NULL);
+ if (ptime->year > 9999 /* RFC1123 limitation */ ||
+ ptime->month == 0 || ptime->month > 12 ||
+ ptime->day == 0 || ptime->day > 31 ||
+ ptime->hour > 23 || ptime->minute > 59 ||
+ ptime->second > 60)
+ {
+ png_warning(png_ptr, "Ignoring invalid time value");
+ return (NULL);
+ }
+
{
size_t pos = 0;
- char number_buf[5]; /* enough for a four digit year */
+ char number_buf[5]; /* enough for a four-digit year */
# define APPEND_STRING(string)\
pos = png_safecat(png_ptr->time_buffer, sizeof png_ptr->time_buffer,\
pos, (string))
@@ -611,19 +621,19 @@
# define APPEND(ch)\
if (pos < (sizeof png_ptr->time_buffer)-1)\
png_ptr->time_buffer[pos++] = (ch)
- APPEND_NUMBER(PNG_NUMBER_FORMAT_u, (unsigned)ptime->day % 32);
+ APPEND_NUMBER(PNG_NUMBER_FORMAT_u, (unsigned)ptime->day);
APPEND(' ');
- APPEND_STRING(short_months[(ptime->month - 1) % 12]);
+ APPEND_STRING(short_months[(ptime->month - 1)]);
APPEND(' ');
APPEND_NUMBER(PNG_NUMBER_FORMAT_u, ptime->year);
APPEND(' ');
- APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->hour % 24);
+ APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->hour);
APPEND(':');
- APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->minute % 60);
+ APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->minute);
APPEND(':');
- APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->second % 61);
+ APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->second);
APPEND_STRING(" +0000"); /* This reliably terminates the buffer */
# undef APPEND
# undef APPEND_NUMBER
@@ -2163,11 +2173,11 @@
*/
static png_uint_32
png_8bit_l2[128] =
{
-# if PNG_DO_BC
+# ifdef PNG_DO_BC
for (i=128;i<256;++i) { .5 - l(i/255)/l(2)*65536*65536; }
-# endif
+# else
4270715492U, 4222494797U, 4174646467U, 4127164793U, 4080044201U, 4033279239U,
3986864580U, 3940795015U, 3895065449U, 3849670902U, 3804606499U, 3759867474U,
3715449162U, 3671346997U, 3627556511U, 3584073329U, 3540893168U, 3498011834U,
3455425220U, 3413129301U, 3371120137U, 3329393864U, 3287946700U, 3246774933U,
@@ -2188,8 +2198,10 @@
479792461U, 453592303U, 427502463U, 401522014U, 375650043U, 349885648U,
324227938U, 298676034U, 273229066U, 247886176U, 222646516U, 197509248U,
172473545U, 147538590U, 122703574U, 97967701U, 73330182U, 48790236U,
24347096U, 0U
+# endif
+
#if 0
/* The following are the values for 16-bit tables - these work fine for the
* 8-bit conversions but produce very slightly larger errors in the 16-bit
* log (about 1.2 as opposed to 0.7 absolute error in the final value). To
@@ -2322,9 +2334,9 @@
* each case only the low 16 bits are relevant - the fraction - since the
* integer bits (the top 4) simply determine a shift.
*
* The worst case is the 16-bit distinction between 65535 and 65534, this
- * requires perhaps spurious accuracty in the decoding of the logarithm to
+ * requires perhaps spurious accuracy in the decoding of the logarithm to
* distinguish log2(65535/65534.5) - 10^-5 or 17 bits. There is little chance
* of getting this accuracy in practice.
*
* To deal with this the following exp() function works out the exponent of the
@@ -2333,19 +2345,20 @@
*/
static png_uint_32
png_32bit_exp[16] =
{
-# if PNG_DO_BC
+# ifdef PNG_DO_BC
for (i=0;i<16;++i) { .5 + e(-i/16*l(2))*2^32; }
-# endif
+# else
/* NOTE: the first entry is deliberately set to the maximum 32-bit value. */
4294967295U, 4112874773U, 3938502376U, 3771522796U, 3611622603U, 3458501653U,
3311872529U, 3171459999U, 3037000500U, 2908241642U, 2784941738U, 2666869345U,
2553802834U, 2445529972U, 2341847524U, 2242560872U
+# endif
};
/* Adjustment table; provided to explain the numbers in the code below. */
-#if PNG_DO_BC
+#ifdef PNG_DO_BC
for (i=11;i>=0;--i){ print i, " ", (1 - e(-(2^i)/65536*l(2))) * 2^(32-i), "\n"}
11 44937.64284865548751208448
10 45180.98734845585101160448
9 45303.31936980687359311872
@@ -2506,9 +2519,9 @@
gamma_val > PNG_FP_1 + PNG_GAMMA_THRESHOLD_FIXED;
}
/* Internal function to build a single 16-bit table - the table consists of
- * 'num' 256 entry subtables, where 'num' is determined by 'shift' - the amount
+ * 'num' 256-entry subtables, where 'num' is determined by 'shift' - the amount
* to shift the input values right (or 16-number_of_signifiant_bits).
*
* The caller is responsible for ensuring that the table gets cleaned up on
* png_error (i.e. if one of the mallocs below fails) - i.e. the *table argument
@@ -2593,11 +2606,11 @@
png_uint_16pp table = *ptable =
(png_uint_16pp)png_calloc(png_ptr, num * png_sizeof(png_uint_16p));
- /* 'num' is the number of tables and also the number of low bits of low
- * bits of the input 16-bit value used to select a table. Each table is
- * itself index by the high 8 bits of the value.
+ /* 'num' is the number of tables and also the number of low bits of the
+ * input 16-bit value used to select a table. Each table is itself indexed
+ * by the high 8 bits of the value.
*/
for (i = 0; i < num; i++)
table[i] = (png_uint_16p)png_malloc(png_ptr,
256 * png_sizeof(png_uint_16));
@@ -2646,9 +2659,9 @@
}
/* Build a single 8-bit table: same as the 16-bit case but much simpler (and
* typically much faster). Note that libpng currently does no sBIT processing
- * (apparently contrary to the spec) so a 256 entry table is always generated.
+ * (apparently contrary to the spec) so a 256-entry table is always generated.
*/
static void
png_build_8bit_table(png_structp png_ptr, png_bytepp ptable,
PNG_CONST png_fixed_point gamma_val)
@@ -2782,9 +2795,9 @@
*
* Where 'iv' is the input color value and 'ov' is the output value -
* pow(iv, gamma).
*
- * Thus the gamma table consists of up to 256 256 entry tables. The table
+ * Thus the gamma table consists of up to 256 256-entry tables. The table
* is selected by the (8-gamma_shift) most significant of the low 8 bits of
* the color value then indexed by the upper 8 bits:
*
* table[low bits][high 8 bits]
diff -ru4NwbB libpng-1.5.6/png.h libpng-1.5.7/png.h
--- libpng-1.5.6/png.h 2011-11-02 22:42:50.344556602 -0500
+++ libpng-1.5.7/png.h 2011-12-15 09:45:32.416549858 -0600
@@ -162,8 +162,11 @@
* 1.5.5 15 10505 15.so.15.5[.0]
* 1.5.6beta01-07 15 10506 15.so.15.6[.0]
* 1.5.6rc01-03 15 10506 15.so.15.6[.0]
* 1.5.6 15 10506 15.so.15.6[.0]
+ * 1.5.7beta01-05 15 10507 15.so.15.7[.0]
+ * 1.5.7rc01-03 15 10507 15.so.15.7[.0]
+ * 1.5.7 15 10507 15.so.15.7[.0]
*
* Henceforth the source version will match the shared-library major
* and minor numbers; the shared-library major version number will be
* used for changes in backward compatibility, as it is intended. The
@@ -363,8 +366,11 @@
/* This is not the place to learn how to use libpng. The file libpng-manual.txt
* describes how to use libpng, and the file example.c summarizes it
* with some code on which to build. This file is useful for looking
* at the actual function definitions and structure components.
+ *
+ * If you just need to read a PNG file and don't want to read the documentation
+ * skip to the end of this file and read the section entitled 'simplified API'.
*/
/* Version information for png.h - this should match the version in png.c */
#define PNG_LIBPNG_VER_STRING "1.5.7"
@@ -603,13 +610,22 @@
#ifdef PNG_TEXT_SUPPORTED
/* png_text holds the contents of a text/ztxt/itxt chunk in a PNG file,
* and whether that contents is compressed or not. The "key" field
- * points to a regular zero-terminated C string. The "text", "lang", and
- * "lang_key" fields can be regular C strings, empty strings, or NULL pointers.
+ * points to a regular zero-terminated C string. The "text" fields can be a
+ * regular C string, an empty string, or a NULL pointer.
* However, the structure returned by png_get_text() will always contain
- * regular zero-terminated C strings (possibly empty), never NULL pointers,
- * so they can be safely used in printf() and other string-handling functions.
+ * the "text" field as a regular zero-terminated C string (possibly
+ * empty), never a NULL pointer, so it can be safely used in printf() and
+ * other string-handling functions. Note that the "itxt_length", "lang", and
+ * "lang_key" members of the structure only exist when the library is built
+ * with iTXt chunk support. Prior to libpng-1.4.0 the library was built by
+ * default without iTXt support. Also note that when iTXt *is* supported,
+ * the "lang" and "lang_key" fields contain NULL pointers when the
+ * "compression" field contains * PNG_TEXT_COMPRESSION_NONE or
+ * PNG_TEXT_COMPRESSION_zTXt. Note that the "compression value" is not the
+ * same as what appears in the PNG tEXt/zTXt/iTXt chunk's "compression flag"
+ * which is always 0 or 1, or its "compression method" which is always 0.
*/
typedef struct png_text_struct
{
int compression; /* compression value:
@@ -1122,8 +1138,13 @@
#endif
#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
/* Reduce RGB to grayscale. */
+#define PNG_ERROR_ACTION_NONE 1
+#define PNG_ERROR_ACTION_WARN 2
+#define PNG_ERROR_ACTION_ERROR 3
+#define PNG_RGB_TO_GRAY_DEFAULT (-1)/*for red/green coefficients*/
+
PNG_FP_EXPORT(32, void, png_set_rgb_to_gray, (png_structp png_ptr,
int error_action, double red, double green));
PNG_FIXED_EXPORT(33, void, png_set_rgb_to_gray_fixed, (png_structp png_ptr,
int error_action, png_fixed_point red, png_fixed_point green));
diff -ru4NwbB libpng-1.5.6/pngconf.h libpng-1.5.7/pngconf.h
--- libpng-1.5.6/pngconf.h 2011-11-02 22:42:50.351894226 -0500
+++ libpng-1.5.7/pngconf.h 2011-12-15 09:45:32.423656205 -0600
@@ -368,9 +368,9 @@
# ifndef PNG_NORETURN
# define PNG_NORETURN __declspec(noreturn)
# endif
# ifndef PNG_ALLOCATED
-# if defined(_MSC_VER) && (_MSC_VER >= 1300)
+# if (_MSC_VER >= 1400)
# define PNG_ALLOCATED __declspec(restrict)
# endif
# endif
# ifndef PNG_DEPRECATED
diff -ru4NwbB libpng-1.5.6/pngerror.c libpng-1.5.7/pngerror.c
--- libpng-1.5.6/pngerror.c 2011-11-02 22:42:50.406539999 -0500
+++ libpng-1.5.7/pngerror.c 2011-12-15 09:45:32.479000733 -0600
@@ -1,8 +1,8 @@
/* pngerror.c - stub functions for i/o and memory allocation
*
- * Last changed in libpng 1.5.6 [December 15, 2011]
+ * Last changed in libpng 1.5.7 [December 15, 2011]
* Copyright (c) 1998-2011 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
*
diff -ru4NwbB libpng-1.5.6/pngget.c libpng-1.5.7/pngget.c
--- libpng-1.5.6/pngget.c 2011-11-02 22:42:50.414779399 -0500
+++ libpng-1.5.7/pngget.c 2011-12-15 09:45:32.487133629 -0600
@@ -1,8 +1,8 @@
/* pngget.c - retrieval of values from info struct
*
- * Last changed in libpng 1.5.6 [December 15, 2011]
+ * Last changed in libpng 1.5.7 [December 15, 2011]
* Copyright (c) 1998-2011 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
*
@@ -681,17 +681,18 @@
{
png_debug1(1, "in %s retrieval function", "iCCP");
if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_iCCP)
- && name != NULL && profile != NULL && proflen != NULL)
+ && name != NULL && compression_type != NULL && profile != NULL &&
+ proflen != NULL)
{
*name = info_ptr->iccp_name;
*profile = info_ptr->iccp_profile;
/* Compression_type is a dummy so the API won't have to change
* if we introduce multiple compression types later.
*/
- *proflen = (int)info_ptr->iccp_proflen;
- *compression_type = (int)info_ptr->iccp_compression;
+ *proflen = info_ptr->iccp_proflen;
+ *compression_type = info_ptr->iccp_compression;
return (PNG_INFO_iCCP);
}
return (0);
diff -ru4NwbB libpng-1.5.6/pngmem.c libpng-1.5.7/pngmem.c
--- libpng-1.5.6/pngmem.c 2011-11-02 22:42:50.421685471 -0500
+++ libpng-1.5.7/pngmem.c 2011-12-15 09:45:32.494039954 -0600
@@ -1,8 +1,8 @@
/* pngmem.c - stub functions for memory allocation
*
- * Last changed in libpng 1.5.4 [July 7, 2011]
+ * Last changed in libpng 1.5.7 [December 15, 2011]
* Copyright (c) 1998-2011 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
*
@@ -55,11 +55,11 @@
# ifdef PNG_USER_MEM_SUPPORTED
if (malloc_fn != NULL)
{
png_struct dummy_struct;
- png_structp png_ptr = &dummy_struct;
- png_ptr->mem_ptr=mem_ptr;
- struct_ptr = (*(malloc_fn))(png_ptr, (png_uint_32)size);
+ memset(&dummy_struct, 0, sizeof dummy_struct);
+ dummy_struct.mem_ptr=mem_ptr;
+ struct_ptr = (*(malloc_fn))(&dummy_struct, (png_alloc_size_t)size);
}
else
# endif /* PNG_USER_MEM_SUPPORTED */
@@ -89,11 +89,11 @@
# ifdef PNG_USER_MEM_SUPPORTED
if (free_fn != NULL)
{
png_struct dummy_struct;
- png_structp png_ptr = &dummy_struct;
- png_ptr->mem_ptr=mem_ptr;
- (*(free_fn))(png_ptr, struct_ptr);
+ memset(&dummy_struct, 0, sizeof dummy_struct);
+ dummy_struct.mem_ptr=mem_ptr;
+ (*(free_fn))(&dummy_struct, struct_ptr);
return;
}
# endif /* PNG_USER_MEM_SUPPORTED */
@@ -142,9 +142,9 @@
return (NULL);
# ifdef PNG_USER_MEM_SUPPORTED
if (png_ptr->malloc_fn != NULL)
- ret = ((png_voidp)(*(png_ptr->malloc_fn))(png_ptr, (png_size_t)size));
+ ret = ((png_voidp)(*(png_ptr->malloc_fn))(png_ptr, size));
else
ret = (png_malloc_default(png_ptr, size));
diff -ru4NwbB libpng-1.5.6/pngpread.c libpng-1.5.7/pngpread.c
--- libpng-1.5.6/pngpread.c 2011-11-02 22:42:50.431199446 -0500
+++ libpng-1.5.7/pngpread.c 2011-12-15 09:45:32.503773794 -0600
@@ -1,8 +1,8 @@
/* pngpread.c - read a png file in push mode
*
- * Last changed in libpng 1.5.6 [December 15, 2011]
+ * Last changed in libpng 1.5.7 [December 15, 2011]
* Copyright (c) 1998-2011 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
*
@@ -984,9 +984,9 @@
if (png_ptr->row_buf[0] > PNG_FILTER_VALUE_NONE)
{
if (png_ptr->row_buf[0] < PNG_FILTER_VALUE_LAST)
- png_read_filter_row(&row_info, png_ptr->row_buf + 1,
+ png_read_filter_row(png_ptr, &row_info, png_ptr->row_buf + 1,
png_ptr->prev_row + 1, png_ptr->row_buf[0]);
else
png_error(png_ptr, "bad adaptive filter value");
}
diff -ru4NwbB libpng-1.5.6/pngpriv.h libpng-1.5.7/pngpriv.h
--- libpng-1.5.6/pngpriv.h 2011-11-02 22:42:50.361693834 -0500
+++ libpng-1.5.7/pngpriv.h 2011-12-15 09:45:32.433566044 -0600
@@ -5,9 +5,9 @@
* Copyright (c) 1998-2011 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
*
- * Last changed in libpng 1.5.6 [December 15, 2011]
+ * Last changed in libpng 1.5.7 [December 15, 2011]
*
* This code is released under the libpng license.
* For conditions of distribution and use, see the disclaimer
* and license in png.h
@@ -195,8 +195,25 @@
#ifndef PNG_STATIC
# define PNG_STATIC static
#endif
+/* C99 restrict is used where possible, to do this 'restrict' is defined as
+ * empty if we can't be sure it is supported. configure builds have already
+ * done this work.
+ */
+#ifdef PNG_CONFIGURE_LIBPNG
+# define PNG_RESTRICT restrict
+#else
+ /* Modern compilers support restrict, but assume not for anything not
+ * recognized here:
+ */
+# if defined __GNUC__ || defined _MSC_VER || defined __WATCOMC__
+# define PNG_RESTRICT restrict
+# else
+# define PNG_RESTRICT
+# endif
+#endif
+
/* If warnings or errors are turned off the code is disabled or redirected here.
* From 1.5.4 functions have been added to allow very limited formatting of
* error and warning messages - this code will also be disabled here.
*/
@@ -216,17 +233,30 @@
# define png_chunk_error(s1,s2) png_err(s1)
# define png_fixed_error(s1,s2) png_err(s1)
#endif
+/* C allows up-casts from (void*) to any pointer and (const void*) to any
+ * pointer to a const object. C++ regards this as a type error and requires an
+ * explicit, static, cast and provides the static_cast<> rune to ensure that
+ * const is not cast away.
+ */
+#ifdef __cplusplus
+# define png_voidcast(type, value) static_cast<type>(value)
+#else
+# define png_voidcast(type, value) (value)
+#endif /* __cplusplus */
+
#ifndef PNG_EXTERN
/* The functions exported by PNG_EXTERN are internal functions, which
* aren't usually used outside the library (as far as I know), so it is
* debatable if they should be exported at all. In the future, when it
* is possible to have run-time registry of chunk-handling functions,
* some of these might be made available again.
-# define PNG_EXTERN extern
+ *
+ * 1.5.7: turned the use of 'extern' back on, since it is localized to pngpriv.h
+ * it should be safe now (it is unclear why it was turned off.)
*/
-# define PNG_EXTERN
+# define PNG_EXTERN extern
#endif
/* Some fixed point APIs are still required even if not exported because
* they get used by the corresponding floating point APIs. This magic
@@ -921,11 +951,26 @@
/* Unfilter a row: check the filter value before calling this, there is no point
* calling it for PNG_FILTER_VALUE_NONE.
*/
-PNG_EXTERN void png_read_filter_row PNGARG((png_row_infop row_info,
+PNG_EXTERN void png_read_filter_row PNGARG((png_structp pp, png_row_infop row_info,
png_bytep row, png_const_bytep prev_row, int filter));
+PNG_EXTERN void png_read_filter_row_up_neon PNGARG((png_row_infop row_info,
+ png_bytep row, png_const_bytep prev_row));
+PNG_EXTERN void png_read_filter_row_sub3_neon PNGARG((png_row_infop row_info,
+ png_bytep row, png_const_bytep prev_row));
+PNG_EXTERN void png_read_filter_row_sub4_neon PNGARG((png_row_infop row_info,
+ png_bytep row, png_const_bytep prev_row));
+PNG_EXTERN void png_read_filter_row_avg3_neon PNGARG((png_row_infop row_info,
+ png_bytep row, png_const_bytep prev_row));
+PNG_EXTERN void png_read_filter_row_avg4_neon PNGARG((png_row_infop row_info,
+ png_bytep row, png_const_bytep prev_row));
+PNG_EXTERN void png_read_filter_row_paeth3_neon PNGARG((png_row_infop row_info,
+ png_bytep row, png_const_bytep prev_row));
+PNG_EXTERN void png_read_filter_row_paeth4_neon PNGARG((png_row_infop row_info,
+ png_bytep row, png_const_bytep prev_row));
+
/* Choose the best filter to use and filter the row data */
PNG_EXTERN void png_write_find_filter PNGARG((png_structp png_ptr,
png_row_infop row_info));
diff -ru4NwbB libpng-1.5.6/pngread.c libpng-1.5.7/pngread.c
--- libpng-1.5.6/pngread.c 2011-11-02 22:42:50.439731962 -0500
+++ libpng-1.5.7/pngread.c 2011-12-15 09:45:32.512490496 -0600
@@ -1,8 +1,8 @@
/* pngread.c - read a PNG file
*
- * Last changed in libpng 1.5.6 [December 15, 2011]
+ * Last changed in libpng 1.5.7 [December 15, 2011]
* Copyright (c) 1998-2011 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
*
@@ -79,10 +79,11 @@
#endif
#ifdef PNG_SETJMP_SUPPORTED
/* Applications that neglect to set up their own setjmp() and then
- encounter a png_error() will longjmp here. Since the jmpbuf is
- then meaningless we abort instead of returning. */
+ * encounter a png_error() will longjmp here. Since the jmpbuf is
+ * then meaningless we abort instead of returning.
+ */
#ifdef USE_FAR_KEYWORD
if (setjmp(tmp_jmpbuf))
#else
if (setjmp(png_jmpbuf(png_ptr))) /* Sets longjmp to match setjmp */
@@ -577,9 +578,9 @@
if (png_ptr->row_buf[0] > PNG_FILTER_VALUE_NONE)
{
if (png_ptr->row_buf[0] < PNG_FILTER_VALUE_LAST)
- png_read_filter_row(&row_info, png_ptr->row_buf + 1,
+ png_read_filter_row(png_ptr, &row_info, png_ptr->row_buf + 1,
png_ptr->prev_row + 1, png_ptr->row_buf[0]);
else
png_error(png_ptr, "bad adaptive filter value");
}
diff -ru4NwbB libpng-1.5.6/pngrtran.c libpng-1.5.7/pngrtran.c
--- libpng-1.5.6/pngrtran.c 2011-11-02 22:42:50.462840407 -0500
+++ libpng-1.5.7/pngrtran.c 2011-12-15 09:45:32.535877370 -0600
@@ -1,8 +1,8 @@
/* pngrtran.c - transforms the data in a row for PNG readers
*
- * Last changed in libpng 1.5.6 [December 15, 2011]
+ * Last changed in libpng 1.5.7 [December 15, 2011]
* Copyright (c) 1998-2011 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
*
@@ -935,17 +935,17 @@
return;
switch(error_action)
{
- case 1:
+ case PNG_ERROR_ACTION_NONE:
png_ptr->transformations |= PNG_RGB_TO_GRAY;
break;
- case 2:
+ case PNG_ERROR_ACTION_WARN:
png_ptr->transformations |= PNG_RGB_TO_GRAY_WARN;
break;
- case 3:
+ case PNG_ERROR_ACTION_ERROR:
png_ptr->transformations |= PNG_RGB_TO_GRAY_ERR;
break;
default:
@@ -1464,8 +1464,30 @@
# undef CHOP
}
#endif /* PNG_READ_BACKGROUND_SUPPORTED && PNG_READ_EXPAND_16_SUPPORTED */
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
+ (defined(PNG_READ_SCALE_16_TO_8_SUPPORTED) || \
+ defined(PNG_READ_STRIP_16_TO_8_SUPPORTED))
+ if ((png_ptr->transformations & (PNG_16_TO_8|PNG_SCALE_16_TO_8)) &&
+ (png_ptr->transformations & PNG_COMPOSE) &&
+ !(png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
+ png_ptr->bit_depth == 16)
+ {
+ /* On the other hand, if a 16-bit file is to be reduced to 8-bits per
+ * component this will also happen after PNG_COMPOSE and so the background
+ * color must be pre-expanded here.
+ *
+ * TODO: fix this too.
+ */
+ png_ptr->background.red = (png_uint_16)(png_ptr->background.red * 257);
+ png_ptr->background.green =
+ (png_uint_16)(png_ptr->background.green * 257);
+ png_ptr->background.blue = (png_uint_16)(png_ptr->background.blue * 257);
+ png_ptr->background.gray = (png_uint_16)(png_ptr->background.gray * 257);
+ }
+#endif
+
/* NOTE: below 'PNG_READ_ALPHA_MODE_SUPPORTED' is presumed to also enable the
* background support (see the comments in scripts/pnglibconf.dfa), this
* allows pre-multiplication of the alpha channel to be implemented as
* compositing on black. This is probably sub-optimal and has been done in
@@ -1511,8 +1533,18 @@
#ifdef PNG_READ_BACKGROUND_SUPPORTED
if (png_ptr->transformations & PNG_COMPOSE)
{
+ /* Issue a warning about this combination: because RGB_TO_GRAY is
+ * optimized to do the gamma transform if present yet do_background has
+ * to do the same thing if both options are set a
+ * double-gamma-correction happens. This is true in all versions of
+ * libpng to date.
+ */
+ if (png_ptr->transformations & PNG_RGB_TO_GRAY)
+ png_warning(png_ptr,
+ "libpng does not support gamma+background+rgb_to_gray");
+
if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
{
/* We don't get to here unless there is a tRNS chunk with non-opaque
* entries - see the checking code at the start of this function.
@@ -1725,9 +1757,15 @@
else
/* Transformation does not include PNG_BACKGROUND */
#endif /* PNG_READ_BACKGROUND_SUPPORTED */
- if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+ if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+ /* RGB_TO_GRAY needs to have non-gamma-corrected values! */
+ && ((png_ptr->transformations & PNG_EXPAND) == 0 ||
+ (png_ptr->transformations & PNG_RGB_TO_GRAY) == 0)
+#endif
+ )
{
png_colorp palette = png_ptr->palette;
int num_palette = png_ptr->num_palette;
int i;
@@ -1917,9 +1955,9 @@
png_ptr->transformations |= PNG_16_TO_8;
info_ptr->bit_depth = 8;
# else
-# if PNG_READ_SCALE_16_TO_8_SUPPORTED
+# ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
png_ptr->transformations |= PNG_SCALE_16_TO_8;
info_ptr->bit_depth = 8;
# else
@@ -2164,14 +2202,24 @@
#endif
#ifdef PNG_READ_GAMMA_SUPPORTED
if ((png_ptr->transformations & PNG_GAMMA) &&
+#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
+ /* Because RGB_TO_GRAY does the gamma transform. */
+ !(png_ptr->transformations & PNG_RGB_TO_GRAY) &&
+#endif
#if (defined PNG_READ_BACKGROUND_SUPPORTED) ||\
(defined PNG_READ_ALPHA_MODE_SUPPORTED)
+ /* Because PNG_COMPOSE does the gamma transform if there is something to
+ * do (if there is an alpha channel or transparency.)
+ */
!((png_ptr->transformations & PNG_COMPOSE) &&
((png_ptr->num_trans != 0) ||
(png_ptr->color_type & PNG_COLOR_MASK_ALPHA))) &&
#endif
+ /* Because png_init_read_transformations transforms the palette, unless
+ * RGB_TO_GRAY will do the transform.
+ */
(png_ptr->color_type != PNG_COLOR_TYPE_PALETTE))
png_do_gamma(row_info, png_ptr->row_buf + 1, png_ptr);
#endif
@@ -2561,9 +2609,9 @@
if (row_info->bit_depth == 16)
{
png_bytep sp = row; /* source */
- png_bytep dp = row; /* destinaton */
+ png_bytep dp = row; /* destination */
png_bytep ep = sp + row_info->rowbytes; /* end+1 */
while (sp < ep)
{
@@ -2622,9 +2670,9 @@
if (row_info->bit_depth == 16)
{
png_bytep sp = row; /* source */
- png_bytep dp = row; /* destinaton */
+ png_bytep dp = row; /* destination */
png_bytep ep = sp + row_info->rowbytes; /* end+1 */
while (sp < ep)
{
@@ -3330,9 +3378,9 @@
if (red != green || red != blue)
rgb_error |= 1;
- /* From 1.5.5 in the 16 bit case do the accurate convertion even
+ /* From 1.5.5 in the 16 bit case do the accurate conversion even
* in the 'fast' case - this is because this is where the code
* ends up when handling linear 16 bit data.
*/
gray16 = (png_uint_16)((rc*red + gc*green + bc*blue + 16384) >>
diff -ru4NwbB libpng-1.5.6/pngrutil.c libpng-1.5.7/pngrutil.c
--- libpng-1.5.6/pngrutil.c 2011-11-02 22:42:50.478366695 -0500
+++ libpng-1.5.7/pngrutil.c 2011-12-15 09:45:32.551997710 -0600
@@ -1,8 +1,8 @@
/* pngrutil.c - utilities to read a PNG file
*
- * Last changed in libpng 1.5.6 [December 15, 2011]
+ * Last changed in libpng 1.5.7 [December 15, 2011]
* Copyright (c) 1998-2011 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
*
@@ -489,9 +489,9 @@
else /* if (comp_type != PNG_COMPRESSION_TYPE_BASE) */
{
PNG_WARNING_PARAMETERS(p)
png_warning_parameter_signed(p, 1, PNG_NUMBER_FORMAT_d, comp_type);
- png_formatted_warning(png_ptr, p, "Unknown zTXt compression type @1");
+ png_formatted_warning(png_ptr, p, "Unknown compression type @1");
/* The recovery is to simply drop the data. */
}
@@ -2539,8 +2539,16 @@
comp_flag = *lang++;
comp_type = *lang++;
}
+ if (comp_type || (comp_flag && comp_flag != PNG_TEXT_COMPRESSION_zTXt))
+ {
+ png_warning(png_ptr, "Unknown iTXt compression type or method");
+ png_free(png_ptr, png_ptr->chunkdata);
+ png_ptr->chunkdata = NULL;
+ return;
+ }
+
for (lang_key = lang; *lang_key; lang_key++)
/* Empty loop */ ;
lang_key++; /* Skip NUL separator */
@@ -2766,20 +2774,15 @@
chunk_name >>= 8;
}
}
-/* Combines the row recently read in with the existing pixels in the
- * row. This routine takes care of alpha and transparency if requested.
- * This routine also handles the two methods of progressive display
- * of interlaced images, depending on the mask value.
- * The mask value describes which pixels are to be combined with
- * the row. The pattern always repeats every 8 pixels, so just 8
- * bits are needed. A one indicates the pixel is to be combined,
- * a zero indicates the pixel is to be skipped. This is in addition
- * to any alpha or transparency value associated with the pixel. If
- * you want all pixels to be combined, pass 0xff (255) in mask.
+/* Combines the row recently read in with the existing pixels in the row. This
+ * routine takes care of alpha and transparency if requested. This routine also
+ * handles the two methods of progressive display of interlaced images,
+ * depending on the 'display' value; if 'display' is true then the whole row
+ * (dp) is filled from the start by replicating the available pixels. If
+ * 'display' is false only those pixels present in the pass are filled in.
*/
-
void /* PRIVATE */
png_combine_row(png_structp png_ptr, png_bytep dp, int display)
{
unsigned int pixel_depth = png_ptr->transformed_pixel_depth;
@@ -2849,26 +2852,26 @@
return;
if (pixel_depth < 8)
{
- /* For pixel depths up to 4-bpp the 8-pixel mask can be expanded to fit
+ /* For pixel depths up to 4 bpp the 8-pixel mask can be expanded to fit
* into 32 bits, then a single loop over the bytes using the four byte
* values in the 32-bit mask can be used. For the 'display' option the
* expanded mask may also not require any masking within a byte. To
* make this work the PACKSWAP option must be taken into account - it
* simply requires the pixels to be reversed in each byte.
*
* The 'regular' case requires a mask for each of the first 6 passes,
* the 'display' case does a copy for the even passes in the range
- * 0..6. This has already been handled in the tst above.
+ * 0..6. This has already been handled in the test above.
*
* The masks are arranged as four bytes with the first byte to use in
* the lowest bits (little-endian) regardless of the order (PACKSWAP or
* not) of the pixels in each byte.
*
* NOTE: the whole of this logic depends on the caller of this function
* only calling it on rows appropriate to the pass. This function only
- * understands the 'x' logic, the 'y' logic is handled by the caller.
+ * understands the 'x' logic; the 'y' logic is handled by the caller.
*
* The following defines allow generation of compile time constant bit
* masks for each pixel depth and each possibility of swapped or not
* swapped bytes. Pass 'p' is in the range 0..6; 'x', a pixel index,
@@ -2884,9 +2887,9 @@
* because the right hand side of the ?: expression is evaluated by
* the compiler even though it isn't used. Microsoft Visual C (various
* versions) and the Intel C compiler are known to do this. To avoid
* this the following macros are used in 1.5.6. This is a temporary
- * solution to avoid destablizing the code during the release process.
+ * solution to avoid destabilizing the code during the release process.
*/
# if PNG_USE_COMPILE_TIME_MASKS
# define PNG_LSR(x,s) ((x)>>((s) & 0x1f))
# define PNG_LSL(x,s) ((x)<<((s) & 0x1f))
@@ -2929,9 +2932,9 @@
#if PNG_USE_COMPILE_TIME_MASKS
/* Utility macros to construct all the masks for a depth/swap
* combination. The 's' parameter says whether the format is PNG
- * (big endian bytes) or not. Only the three odd numbered passes are
+ * (big endian bytes) or not. Only the three odd-numbered passes are
* required for the display/block algorithm.
*/
# define S_MASKS(d,s) { S_MASK(0,d,s), S_MASK(1,d,s), S_MASK(2,d,s),\
S_MASK(3,d,s), S_MASK(4,d,s), S_MASK(5,d,s) }
@@ -2942,9 +2945,10 @@
/* Hence the pre-compiled masks indexed by PACKSWAP (or not), depth and
* then pass:
*/
- static PNG_CONST png_uint_32 row_mask[2/*PACKSWAP*/][3/*depth*/][6] = {
+ static PNG_CONST png_uint_32 row_mask[2/*PACKSWAP*/][3/*depth*/][6] =
+ {
/* Little-endian byte masks for PACKSWAP */
{ S_MASKS(1,0), S_MASKS(2,0), S_MASKS(4,0) },
/* Normal (big-endian byte) masks - PNG format */
{ S_MASKS(1,1), S_MASKS(2,1), S_MASKS(4,1) }
@@ -2952,9 +2956,10 @@
/* display_mask has only three entries for the odd passes, so index by
* pass>>1.
*/
- static PNG_CONST png_uint_32 display_mask[2][3][3] = {
+ static PNG_CONST png_uint_32 display_mask[2][3][3] =
+ {
/* Little-endian byte masks for PACKSWAP */
{ B_MASKS(1,0), B_MASKS(2,0), B_MASKS(4,0) },
/* Normal (big-endian byte) masks - PNG format */
{ B_MASKS(1,1), B_MASKS(2,1), B_MASKS(4,1) }
@@ -3128,9 +3133,9 @@
#if PNG_ALIGN_TYPE != PNG_ALIGN_NONE
/* Check for double byte alignment and, if possible, use a
* 16-bit copy. Don't attempt this for narrow images - ones that
* are less than an interlace panel wide. Don't attempt it for
- * wide bytes-to-copy either - use the png_memcpy there.
+ * wide bytes_to_copy either - use the png_memcpy there.
*/
if (bytes_to_copy < 16 /*else use png_memcpy*/ &&
png_isaligned(dp, png_uint_16) &&
png_isaligned(sp, png_uint_16) &&
@@ -3497,36 +3502,29 @@
#endif
}
#endif /* PNG_READ_INTERLACING_SUPPORTED */
-/* 1.5.6: Changed to just take a png_row_info (not png_ptr) and to ignore bad
- * adaptive filter bytes.
- */
-void /* PRIVATE */
-png_read_filter_row(png_row_infop row_info, png_bytep row,
- png_const_bytep prev_row, int filter)
-{
- switch (filter)
- {
- case PNG_FILTER_VALUE_NONE:
- break;
-
- case PNG_FILTER_VALUE_SUB:
+static void
+png_read_filter_row_sub(png_row_infop row_info, png_bytep row,
+ png_const_bytep prev_row)
{
png_size_t i;
png_size_t istop = row_info->rowbytes;
unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
png_bytep rp = row + bpp;
- png_bytep lp = row;
+
+ PNG_UNUSED(prev_row)
for (i = bpp; i < istop; i++)
{
- *rp = (png_byte)(((int)(*rp) + (int)(*lp++)) & 0xff);
+ *rp = (png_byte)(((int)(*rp) + (int)(*(rp-bpp))) & 0xff);
rp++;
}
- break;
}
- case PNG_FILTER_VALUE_UP:
+
+static void
+png_read_filter_row_up(png_row_infop row_info, png_bytep row,
+ png_const_bytep prev_row)
{
png_size_t i;
png_size_t istop = row_info->rowbytes;
png_bytep rp = row;
@@ -3536,16 +3534,17 @@
{
*rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
rp++;
}
- break;
}
- case PNG_FILTER_VALUE_AVG:
+
+static void
+png_read_filter_row_avg(png_row_infop row_info, png_bytep row,
+ png_const_bytep prev_row)
{
png_size_t i;
png_bytep rp = row;
png_const_bytep pp = prev_row;
- png_bytep lp = row;
unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
png_size_t istop = row_info->rowbytes - bpp;
for (i = 0; i < bpp; i++)
@@ -3558,37 +3557,88 @@
for (i = 0; i < istop; i++)
{
*rp = (png_byte)(((int)(*rp) +
- (int)(*pp++ + *lp++) / 2 ) & 0xff);
+ (int)(*pp++ + *(rp-bpp)) / 2 ) & 0xff);
rp++;
}
- break;
}
- case PNG_FILTER_VALUE_PAETH:
+
+static void
+png_read_filter_row_paeth_1byte_pixel(png_row_infop row_info, png_bytep row,
+ png_const_bytep prev_row)
{
- png_size_t i;
- png_bytep rp = row;
- png_const_bytep pp = prev_row;
- png_bytep lp = row;
- png_const_bytep cp = prev_row;
- unsigned int bpp = (row_info->pixel_depth + 7) >> 3;
- png_size_t istop=row_info->rowbytes - bpp;
+ png_bytep rp_end = row + row_info->rowbytes;
+ int a, c;
- for (i = 0; i < bpp; i++)
+ /* First pixel/byte */
+ c = *prev_row++;
+ a = *row + c;
+ *row++ = (png_byte)a;
+
+ /* Remainder */
+ while (row < rp_end)
{
- *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
- rp++;
+ int b, pa, pb, pc, p;
+
+ a &= 0xff; /* From previous iteration or start */
+ b = *prev_row++;
+
+ p = b - c;
+ pc = a - c;
+
+# ifdef PNG_USE_ABS
+ pa = abs(p);
+ pb = abs(pc);
+ pc = abs(p + pc);
+# else
+ pa = p < 0 ? -p : p;
+ pb = pc < 0 ? -pc : pc;
+ pc = (p + pc) < 0 ? -(p + pc) : p + pc;
+# endif
+
+ /* Find the best predictor, the least of pa, pb, pc favoring the earlier
+ * ones in the case of a tie.
+ */
+ if (pb < pa) pa = pb, a = b;
+ if (pc < pa) a = c;
+
+ /* Calculate the current pixel in a, and move the previous row pixel to c
+ * for the next time round the loop
+ */
+ c = b;
+ a += *row;
+ *row++ = (png_byte)a;
+ }
+}
+
+static void
+png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info, png_bytep row,
+ png_const_bytep prev_row)
+{
+ int bpp = (row_info->pixel_depth + 7) >> 3;
+ png_bytep rp_end = row + bpp;
+
+ /* Process the first pixel in the row completely (this is the same as 'up'
+ * because there is only one candidate predictor for the first row).
+ */
+ while (row < rp_end)
+ {
+ int a = *row + *prev_row++;
+ *row++ = (png_byte)a;
}
- for (i = 0; i < istop; i++) /* Use leftover rp,pp */
+ /* Remainder */
+ rp_end += row_info->rowbytes - bpp;
+
+ while (row < rp_end)
{
int a, b, c, pa, pb, pc, p;
- a = *lp++;
- b = *pp++;
- c = *cp++;
+ c = *(prev_row - bpp);
+ a = *(row - bpp);
+ b = *prev_row++;
p = b - c;
pc = a - c;
@@ -3601,30 +3651,105 @@
pb = pc < 0 ? -pc : pc;
pc = (p + pc) < 0 ? -(p + pc) : p + pc;
#endif
- /*
- if (pa <= pb && pa <= pc)
- p = a;
+ if (pb < pa) pa = pb, a = b;
+ if (pc < pa) a = c;
+
+ c = b;
+ a += *row;
+ *row++ = (png_byte)a;
+ }
+}
- else if (pb <= pc)
- p = b;
+#ifdef PNG_ARM_NEON
- else
- p = c;
- */
+#ifdef __linux__
+#include <stdio.h>
+#include <elf.h>
+#include <asm/hwcap.h>
- p = (pa <= pb && pa <= pc) ? a : (pb <= pc) ? b : c;
+static int png_have_hwcap(unsigned cap)
+{
+ FILE *f = fopen("/proc/self/auxv", "r");
+ Elf32_auxv_t aux;
+ int have_cap = 0;
- *rp = (png_byte)(((int)(*rp) + p) & 0xff);
- rp++;
- }
+ if (!f)
+ return 0;
+
+ while (fread(&aux, sizeof(aux), 1, f) > 0)
+ {
+ if (aux.a_type == AT_HWCAP &&
+ aux.a_un.a_val & cap)
+ {
+ have_cap = 1;
break;
}
- default:
- /* NOT REACHED */
- break;
}
+
+ fclose(f);
+
+ return have_cap;
+}
+#endif /* __linux__ */
+
+static void
+png_init_filter_functions_neon(png_structp pp, unsigned int bpp)
+{
+#ifdef __linux__
+ if (!png_have_hwcap(HWCAP_NEON))
+ return;
+#endif
+
+ pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_neon;
+
+ if (bpp == 3)
+ {
+ pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_neon;
+ pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_neon;
+ pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
+ png_read_filter_row_paeth3_neon;
+ }
+
+ else if (bpp == 4)
+ {
+ pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_neon;
+ pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_neon;
+ pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
+ png_read_filter_row_paeth4_neon;
+ }
+}
+#endif /* PNG_ARM_NEON */
+
+static void
+png_init_filter_functions(png_structp pp)
+{
+ unsigned int bpp = (pp->pixel_depth + 7) >> 3;
+
+ pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub;
+ pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up;
+ pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg;
+ if (bpp == 1)
+ pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
+ png_read_filter_row_paeth_1byte_pixel;
+ else
+ pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
+ png_read_filter_row_paeth_multibyte_pixel;
+
+#ifdef PNG_ARM_NEON
+ png_init_filter_functions_neon(pp, bpp);
+#endif
+}
+
+void /* PRIVATE */
+png_read_filter_row(png_structp pp, png_row_infop row_info, png_bytep row,
+ png_const_bytep prev_row, int filter)
+{
+ if (pp->read_filter[0] == NULL)
+ png_init_filter_functions(pp);
+ if (filter > PNG_FILTER_VALUE_NONE && filter < PNG_FILTER_VALUE_LAST)
+ pp->read_filter[filter-1](row_info, row, prev_row);
}
#ifdef PNG_SEQUENTIAL_READ_SUPPORTED
void /* PRIVATE */
@@ -3810,8 +3935,18 @@
}
max_pixel_depth = png_ptr->pixel_depth;
+ /* WARNING: * png_read_transform_info (pngrtran.c) performs a simpliar set of
+ * calculations to calculate the final pixel depth, then
+ * png_do_read_transforms actually does the transforms. This means that the
+ * code which effectively calculates this value is actually repeated in three
+ * separate places. They must all match. Innocent changes to the order of
+ * transformations can and will break libpng in a way that causes memory
+ * overwrites.
+ *
+ * TODO: fix this.
+ */
#ifdef PNG_READ_PACK_SUPPORTED
if ((png_ptr->transformations & PNG_PACK) && png_ptr->bit_depth < 8)
max_pixel_depth = 8;
#endif
@@ -3868,21 +4003,19 @@
#ifdef PNG_READ_FILLER_SUPPORTED
if (png_ptr->transformations & (PNG_FILLER))
{
- if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
- max_pixel_depth = 32;
-
- else if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
+ if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
{
if (max_pixel_depth <= 8)
max_pixel_depth = 16;
else
max_pixel_depth = 32;
}
- else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
+ else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB ||
+ png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
{
if (max_pixel_depth <= 32)
max_pixel_depth = 32;
diff -ru4NwbB libpng-1.5.6/pngset.c libpng-1.5.7/pngset.c
--- libpng-1.5.6/pngset.c 2011-11-02 22:42:50.486944000 -0500
+++ libpng-1.5.7/pngset.c 2011-12-15 09:45:32.560605984 -0600
@@ -1,8 +1,8 @@
/* pngset.c - storage of image information into info struct
*
- * Last changed in libpng 1.5.6 [December 15, 2011]
+ * Last changed in libpng 1.5.7 [December 15, 2011]
* Copyright (c) 1998-2011 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
*
@@ -863,8 +863,17 @@
if (png_ptr == NULL || info_ptr == NULL ||
(png_ptr->mode & PNG_WROTE_tIME))
return;
+ if (mod_time->month == 0 || mod_time->month > 12 ||
+ mod_time->day == 0 || mod_time->day > 31 ||
+ mod_time->hour > 23 || mod_time->minute > 59 ||
+ mod_time->second > 60)
+ {
+ png_warning(png_ptr, "Ignoring invalid time value");
+ return;
+ }
+
png_memcpy(&(info_ptr->mod_time), mod_time, png_sizeof(png_time));
info_ptr->valid |= PNG_INFO_tIME;
}
#endif
diff -ru4NwbB libpng-1.5.6/pngstruct.h libpng-1.5.7/pngstruct.h
--- libpng-1.5.6/pngstruct.h 2011-11-02 22:42:50.368044918 -0500
+++ libpng-1.5.7/pngstruct.h 2011-12-15 09:45:32.439964377 -0600
@@ -352,6 +352,9 @@
#endif
/* New member added in libpng-1.5.6 */
png_bytep big_prev_row;
+
+ void (*read_filter[PNG_FILTER_VALUE_LAST-1])(png_row_infop row_info,
+ png_bytep row, png_const_bytep prev_row);
};
#endif /* PNGSTRUCT_H */
diff -ru4NwbB libpng-1.5.6/pngtest.c libpng-1.5.7/pngtest.c
--- libpng-1.5.6/pngtest.c 2011-11-02 22:42:50.496589188 -0500
+++ libpng-1.5.7/pngtest.c 2011-12-15 09:45:32.570338719 -0600
@@ -1,8 +1,8 @@
/* pngtest.c - a simple test program to test libpng
*
- * Last changed in libpng 1.5.6 [December 15, 2011]
+ * Last changed in libpng 1.5.6 [November 3, 2011]
* Copyright (c) 1998-2011 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
*
@@ -1162,8 +1162,12 @@
if (png_get_text(read_ptr, read_info_ptr, &text_ptr, &num_text) > 0)
{
pngtest_debug1("Handling %d iTXt/tEXt/zTXt chunks", num_text);
+
+ if (verbose)
+ printf("\nText compression=%d\n", text_ptr->compression);
+
png_set_text(write_ptr, write_info_ptr, text_ptr, num_text);
}
}
#endif
diff -ru4NwbB libpng-1.5.6/pngvalid.c libpng-1.5.7/pngvalid.c
--- libpng-1.5.6/pngvalid.c 2011-11-02 22:42:50.531808873 -0500
+++ libpng-1.5.7/pngvalid.c 1969-12-31 18:00:00.000000000 -0600
@@ -1,9697 +0,0 @@
-
-/* pngvalid.c - validate libpng by constructing then reading png files.
- *
- * Last changed in libpng 1.5.6 [December 15, 2011]
- * Copyright (c) 2011 Glenn Randers-Pehrson
- * Written by John Cunningham Bowler
- *
- * This code is released under the libpng license.
- * For conditions of distribution and use, see the disclaimer
- * and license in png.h
- *
- * NOTES:
- * This is a C program that is intended to be linked against libpng. It
- * generates bitmaps internally, stores them as PNG files (using the
- * sequential write code) then reads them back (using the sequential
- * read code) and validates that the result has the correct data.
- *
- * The program can be modified and extended to test the correctness of
- * transformations performed by libpng.
- */
-
-#define _POSIX_SOURCE 1
-
-#include "png.h"
-#if PNG_LIBPNG_VER < 10500
-/* This delibarately lacks the PNG_CONST. */
-typedef png_byte *png_const_bytep;
-
-/* This is copied from 1.5.1 png.h: */
-#define PNG_INTERLACE_ADAM7_PASSES 7
-#define PNG_PASS_START_ROW(pass) (((1U&~(pass))<<(3-((pass)>>1)))&7)
-#define PNG_PASS_START_COL(pass) (((1U& (pass))<<(3-(((pass)+1)>>1)))&7)
-#define PNG_PASS_ROW_SHIFT(pass) ((pass)>2?(8-(pass))>>1:3)
-#define PNG_PASS_COL_SHIFT(pass) ((pass)>1?(7-(pass))>>1:3)
-#define PNG_PASS_ROWS(height, pass) (((height)+(((1<<PNG_PASS_ROW_SHIFT(pass))\
- -1)-PNG_PASS_START_ROW(pass)))>>PNG_PASS_ROW_SHIFT(pass))
-#define PNG_PASS_COLS(width, pass) (((width)+(((1<<PNG_PASS_COL_SHIFT(pass))\
- -1)-PNG_PASS_START_COL(pass)))>>PNG_PASS_COL_SHIFT(pass))
-#define PNG_ROW_FROM_PASS_ROW(yIn, pass) \
- (((yIn)<<PNG_PASS_ROW_SHIFT(pass))+PNG_PASS_START_ROW(pass))
-#define PNG_COL_FROM_PASS_COL(xIn, pass) \
- (((xIn)<<PNG_PASS_COL_SHIFT(pass))+PNG_PASS_START_COL(pass))
-#define PNG_PASS_MASK(pass,off) ( \
- ((0x110145AFU>>(((7-(off))-(pass))<<2)) & 0xFU) | \
- ((0x01145AF0U>>(((7-(off))-(pass))<<2)) & 0xF0U))
-#define PNG_ROW_IN_INTERLACE_PASS(y, pass) \
- ((PNG_PASS_MASK(pass,0) >> ((y)&7)) & 1)
-#define PNG_COL_IN_INTERLACE_PASS(x, pass) \
- ((PNG_PASS_MASK(pass,1) >> ((x)&7)) & 1)
-
-/* These are needed too for the default build: */
-#define PNG_WRITE_16BIT_SUPPORTED
-#define PNG_READ_16BIT_SUPPORTED
-
-/* This comes from pnglibconf.h afer 1.5: */
-#define PNG_FP_1 100000
-#define PNG_GAMMA_THRESHOLD_FIXED\
- ((png_fixed_point)(PNG_GAMMA_THRESHOLD * PNG_FP_1))
-#endif
-
-#include "zlib.h" /* For crc32 */
-
-#include <float.h> /* For floating point constants */
-#include <stdlib.h> /* For malloc */
-#include <string.h> /* For memcpy, memset */
-#include <math.h> /* For floor */
-
-/* Unused formal parameter errors are removed using the following macro which is
- * expected to have no bad effects on performance.
- */
-#ifndef UNUSED
-# if defined(__GNUC__) || defined(_MSC_VER)
-# define UNUSED(param) (void)param;
-# else
-# define UNUSED(param)
-# endif
-#endif
-
-/***************************** EXCEPTION HANDLING *****************************/
-#include "contrib/visupng/cexcept.h"
-
-#ifdef __cplusplus
-# define this not_the_cpp_this
-# define new not_the_cpp_new
-# define voidcast(type, value) static_cast<type>(value)
-#else
-# define voidcast(type, value) (value)
-#endif /* __cplusplus */
-
-struct png_store;
-define_exception_type(struct png_store*);
-
-/* The following are macros to reduce typing everywhere where the well known
- * name 'the_exception_context' must be defined.
- */
-#define anon_context(ps) struct exception_context *the_exception_context = \
- &(ps)->exception_context
-#define context(ps,fault) anon_context(ps); png_store *fault
-
-/******************************* UTILITIES ************************************/
-/* Error handling is particularly problematic in production code - error
- * handlers often themselves have bugs which lead to programs that detect
- * minor errors crashing. The following functions deal with one very
- * common class of errors in error handlers - attempting to format error or
- * warning messages into buffers that are too small.
- */
-static size_t safecat(char *buffer, size_t bufsize, size_t pos,
- PNG_CONST char *cat)
-{
- while (pos < bufsize && cat != NULL && *cat != 0)
- buffer[pos++] = *cat++;
-
- if (pos >= bufsize)
- pos = bufsize-1;
-
- buffer[pos] = 0;
- return pos;
-}
-
-static size_t safecatn(char *buffer, size_t bufsize, size_t pos, int n)
-{
- char number[64];
- sprintf(number, "%d", n);
- return safecat(buffer, bufsize, pos, number);
-}
-
-#ifdef PNG_READ_TRANSFORMS_SUPPORTED
-static size_t safecatd(char *buffer, size_t bufsize, size_t pos, double d,
- int precision)
-{
- char number[64];
- sprintf(number, "%.*f", precision, d);
- return safecat(buffer, bufsize, pos, number);
-}
-#endif
-
-static PNG_CONST char invalid[] = "invalid";
-static PNG_CONST char sep[] = ": ";
-
-static PNG_CONST char *colour_types[8] =
-{
- "grayscale", invalid, "truecolour", "indexed-colour",
- "grayscale with alpha", invalid, "truecolour with alpha", invalid
-};
-
-/* Convert a double precision value to fixed point. */
-static png_fixed_point
-fix(double d)
-{
- d = floor(d * PNG_FP_1 + .5);
- return (png_fixed_point)d;
-}
-
-/* Generate random bytes. This uses a boring repeatable algorithm and it
- * is implemented here so that it gives the same set of numbers on every
- * architecture. It's a linear congruential generator (Knuth or Sedgewick
- * "Algorithms") but it comes from the 'feedback taps' table in Horowitz and
- * Hill, "The Art of Electronics".
- */
-static void
-make_random_bytes(png_uint_32* seed, void* pv, size_t size)
-{
- png_uint_32 u0 = seed[0], u1 = seed[1];
- png_bytep bytes = voidcast(png_bytep, pv);
-
- /* There are thirty three bits, the next bit in the sequence is bit-33 XOR
- * bit-20. The top 1 bit is in u1, the bottom 32 are in u0.
- */
- size_t i;
- for (i=0; i<size; ++i)
- {
- /* First generate 8 new bits then shift them in at the end. */
- png_uint_32 u = ((u0 >> (20-8)) ^ ((u1 << 7) | (u0 >> (32-7)))) & 0xff;
- u1 <<= 8;
- u1 |= u0 >> 24;
- u0 <<= 8;
- u0 |= u;
- *bytes++ = (png_byte)u;
- }
-
- seed[0] = u0;
- seed[1] = u1;
-}
-
-static void
-make_four_random_bytes(png_uint_32* seed, png_bytep bytes)
-{
- make_random_bytes(seed, bytes, 4);
-}
-
-static void
-randomize(void *pv, size_t size)
-{
- static png_uint_32 random_seed[2] = {0x56789abc, 0xd};
- make_random_bytes(random_seed, pv, size);
-}
-
-#define RANDOMIZE(this) randomize(&(this), sizeof (this))
-
-static unsigned int
-random_mod(unsigned int max)
-{
- unsigned int x;
-
- RANDOMIZE(x);
-
- return x % max; /* 0 .. max-1 */
-}
-
-static int
-random_choice(void)
-{
- unsigned char x;
-
- RANDOMIZE(x);
-
- return x & 1;
-}
-
-/* A numeric ID based on PNG file characteristics. The 'do_interlace' field
- * simply records whether pngvalid did the interlace itself or whether it
- * was done by libpng. Width and height must be less than 256. 'palette' is an
- * index of the palette to use for formats with a palette (0 otherwise.)
- */
-#define FILEID(col, depth, palette, interlace, width, height, do_interlace) \
- ((png_uint_32)((col) + ((depth)<<3) + ((palette)<<8) + ((interlace)<<13) + \
- (((do_interlace)!=0)<<15) + ((width)<<16) + ((height)<<24)))
-
-#define COL_FROM_ID(id) ((png_byte)((id)& 0x7U))
-#define DEPTH_FROM_ID(id) ((png_byte)(((id) >> 3) & 0x1fU))
-#define PALETTE_FROM_ID(id) ((int)(((id) >> 8) & 0x1f))
-#define INTERLACE_FROM_ID(id) ((int)(((id) >> 13) & 0x3))
-#define DO_INTERLACE_FROM_ID(id) ((int)(((id)>>15) & 1))
-#define WIDTH_FROM_ID(id) (((id)>>16) & 0xff)
-#define HEIGHT_FROM_ID(id) (((id)>>24) & 0xff)
-
-/* Utility to construct a standard name for a standard image. */
-static size_t
-standard_name(char *buffer, size_t bufsize, size_t pos, png_byte colour_type,
- int bit_depth, int npalette, int interlace_type,
- png_uint_32 w, png_uint_32 h, int do_interlace)
-{
- pos = safecat(buffer, bufsize, pos, colour_types[colour_type]);
- if (npalette > 0)
- {
- pos = safecat(buffer, bufsize, pos, "[");
- pos = safecatn(buffer, bufsize, pos, npalette);
- pos = safecat(buffer, bufsize, pos, "]");
- }
- pos = safecat(buffer, bufsize, pos, " ");
- pos = safecatn(buffer, bufsize, pos, bit_depth);
- pos = safecat(buffer, bufsize, pos, " bit");
-
- if (interlace_type != PNG_INTERLACE_NONE)
- {
- pos = safecat(buffer, bufsize, pos, " interlaced");
- if (do_interlace)
- pos = safecat(buffer, bufsize, pos, "(pngvalid)");
- else
- pos = safecat(buffer, bufsize, pos, "(libpng)");
- }
-
- if (w > 0 || h > 0)
- {
- pos = safecat(buffer, bufsize, pos, " ");
- pos = safecatn(buffer, bufsize, pos, w);
- pos = safecat(buffer, bufsize, pos, "x");
- pos = safecatn(buffer, bufsize, pos, h);
- }
-
- return pos;
-}
-
-static size_t
-standard_name_from_id(char *buffer, size_t bufsize, size_t pos, png_uint_32 id)
-{
- return standard_name(buffer, bufsize, pos, COL_FROM_ID(id),
- DEPTH_FROM_ID(id), PALETTE_FROM_ID(id), INTERLACE_FROM_ID(id),
- WIDTH_FROM_ID(id), HEIGHT_FROM_ID(id), DO_INTERLACE_FROM_ID(id));
-}
-
-/* Convenience API and defines to list valid formats. Note that 16 bit read and
- * write support is required to do 16 bit read tests (we must be able to make a
- * 16 bit image to test!)
- */
-#ifdef PNG_WRITE_16BIT_SUPPORTED
-# define WRITE_BDHI 4
-# ifdef PNG_READ_16BIT_SUPPORTED
-# define READ_BDHI 4
-# define DO_16BIT
-# endif
-#else
-# define WRITE_BDHI 3
-#endif
-#ifndef DO_16BIT
-# define READ_BDHI 3
-#endif
-
-/* The following defines the number of different palettes to generate for
- * each log bit depth of a colour type 3 standard image.
- */
-#define PALETTE_COUNT(bit_depth) ((bit_depth) > 4 ? 1 : 16)
-
-static int
-next_format(png_bytep colour_type, png_bytep bit_depth, int* palette_number)
-{
- if (*bit_depth == 0)
- {
- *colour_type = 0, *bit_depth = 1, *palette_number = 0;
- return 1;
- }
-
- if (*colour_type == 3)
- {
- /* Add multiple palettes for colour type 3. */
- if (++*palette_number < PALETTE_COUNT(*bit_depth))
- return 1;
-
- *palette_number = 0;
- }
-
- *bit_depth = (png_byte)(*bit_depth << 1);
-
- /* Palette images are restricted to 8 bit depth */
- if (*bit_depth <= 8
-# ifdef DO_16BIT
- || (*colour_type != 3 && *bit_depth <= 16)
-# endif
- )
- return 1;
-
- /* Move to the next color type, or return 0 at the end. */
- switch (*colour_type)
- {
- case 0:
- *colour_type = 2;
- *bit_depth = 8;
- return 1;
-
- case 2:
- *colour_type = 3;
- *bit_depth = 1;
- return 1;
-
- case 3:
- *colour_type = 4;
- *bit_depth = 8;
- return 1;
-
- case 4:
- *colour_type = 6;
- *bit_depth = 8;
- return 1;
-
- default:
- return 0;
- }
-}
-
-#ifdef PNG_READ_TRANSFORMS_SUPPORTED
-static unsigned int
-sample(png_const_bytep row, png_byte colour_type, png_byte bit_depth,
- png_uint_32 x, unsigned int sample_index)
-{
- png_uint_32 bit_index, result;
-
- /* Find a sample index for the desired sample: */
- x *= bit_depth;
- bit_index = x;
-
- if ((colour_type & 1) == 0) /* !palette */
- {
- if (colour_type & 2)
- bit_index *= 3;
-
- if (colour_type & 4)
- bit_index += x; /* Alpha channel */
-
- /* Multiple channels; select one: */
- if (colour_type & (2+4))
- bit_index += sample_index * bit_depth;
- }
-
- /* Return the sample from the row as an integer. */
- row += bit_index >> 3;
- result = *row;
-
- if (bit_depth == 8)
- return result;
-
- else if (bit_depth > 8)
- return (result << 8) + *++row;
-
- /* Less than 8 bits per sample. */
- bit_index &= 7;
- return (result >> (8-bit_index-bit_depth)) & ((1U<<bit_depth)-1);
-}
-#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
-
-/* Copy a single pixel, of a given size, from one buffer to another -
- * while this is basically bit addressed there is an implicit assumption
- * that pixels 8 or more bits in size are byte aligned and that pixels
- * do not otherwise cross byte boundaries. (This is, so far as I know,
- * universally true in bitmap computer graphics. [JCB 20101212])
- *
- * NOTE: The to and from buffers may be the same.
- */
-static void
-pixel_copy(png_bytep toBuffer, png_uint_32 toIndex,
- png_const_bytep fromBuffer, png_uint_32 fromIndex, unsigned int pixelSize)
-{
- /* Assume we can multiply by 'size' without overflow because we are
- * just working in a single buffer.
- */
- toIndex *= pixelSize;
- fromIndex *= pixelSize;
- if (pixelSize < 8) /* Sub-byte */
- {
- /* Mask to select the location of the copied pixel: */
- unsigned int destMask = ((1U<<pixelSize)-1) << (8-pixelSize-(toIndex&7));
- /* The following read the entire pixels and clears the extra: */
- unsigned int destByte = toBuffer[toIndex >> 3] & ~destMask;
- unsigned int sourceByte = fromBuffer[fromIndex >> 3];
-
- /* Don't rely on << or >> supporting '0' here, just in case: */
- fromIndex &= 7;
- if (fromIndex > 0) sourceByte <<= fromIndex;
- if ((toIndex & 7) > 0) sourceByte >>= toIndex & 7;
-
- toBuffer[toIndex >> 3] = (png_byte)(destByte | (sourceByte & destMask));
- }
- else /* One or more bytes */
- memmove(toBuffer+(toIndex>>3), fromBuffer+(fromIndex>>3), pixelSize>>3);
-}
-
-/* Copy a complete row of pixels, taking into account potential partial
- * bytes at the end.
- */
-static void
-row_copy(png_bytep toBuffer, png_const_bytep fromBuffer, unsigned int bitWidth)
-{
- memcpy(toBuffer, fromBuffer, bitWidth >> 3);
-
- if ((bitWidth & 7) != 0)
- {
- unsigned int mask;
-
- toBuffer += bitWidth >> 3;
- fromBuffer += bitWidth >> 3;
- /* The remaining bits are in the top of the byte, the mask is the bits to
- * retain.
- */
- mask = 0xff >> (bitWidth & 7);
- *toBuffer = (png_byte)((*toBuffer & mask) | (*fromBuffer & ~mask));
- }
-}
-
-/* Compare pixels - they are assumed to start at the first byte in the
- * given buffers.
- */
-static int
-pixel_cmp(png_const_bytep pa, png_const_bytep pb, png_uint_32 bit_width)
-{
-#if PNG_LIBPNG_VER < 10506
- if (memcmp(pa, pb, bit_width>>3) == 0)
- {
- png_uint_32 p;
-
- if ((bit_width & 7) == 0) return 0;
-
- /* Ok, any differences? */
- p = pa[bit_width >> 3];
- p ^= pb[bit_width >> 3];
-
- if (p == 0) return 0;
-
- /* There are, but they may not be significant, remove the bits
- * after the end (the low order bits in PNG.)
- */
- bit_width &= 7;
- p >>= 8-bit_width;
-
- if (p == 0) return 0;
- }
-#else
- /* From libpng-1.5.6 the overwrite should be fixed, so compare the trailing
- * bits too:
- */
- if (memcmp(pa, pb, (bit_width+7)>>3) == 0)
- return 0;
-#endif
-
- /* Return the index of the changed byte. */
- {
- png_uint_32 where = 0;
-
- while (pa[where] == pb[where]) ++where;
- return 1+where;
- }
-}
-
-/*************************** BASIC PNG FILE WRITING ***************************/
-/* A png_store takes data from the sequential writer or provides data
- * to the sequential reader. It can also store the result of a PNG
- * write for later retrieval.
- */
-#define STORE_BUFFER_SIZE 500 /* arbitrary */
-typedef struct png_store_buffer
-{
- struct png_store_buffer* prev; /* NOTE: stored in reverse order */
- png_byte buffer[STORE_BUFFER_SIZE];
-} png_store_buffer;
-
-#define FILE_NAME_SIZE 64
-
-typedef struct store_palette_entry /* record of a single palette entry */
-{
- png_byte red;
- png_byte green;
- png_byte blue;
- png_byte alpha;
-} store_palette_entry, store_palette[256];
-
-typedef struct png_store_file
-{
- struct png_store_file* next; /* as many as you like... */
- char name[FILE_NAME_SIZE];
- png_uint_32 id; /* must be correct (see FILEID) */
- png_size_t datacount; /* In this (the last) buffer */
- png_store_buffer data; /* Last buffer in file */
- int npalette; /* Number of entries in palette */
- store_palette_entry* palette; /* May be NULL */
-} png_store_file;
-
-/* The following is a pool of memory allocated by a single libpng read or write
- * operation.
- */
-typedef struct store_pool
-{
- struct png_store *store; /* Back pointer */
- struct store_memory *list; /* List of allocated memory */
- png_byte mark[4]; /* Before and after data */
-
- /* Statistics for this run. */
- png_alloc_size_t max; /* Maximum single allocation */
- png_alloc_size_t current; /* Current allocation */
- png_alloc_size_t limit; /* Highest current allocation */
- png_alloc_size_t total; /* Total allocation */
-
- /* Overall statistics (retained across successive runs). */
- png_alloc_size_t max_max;
- png_alloc_size_t max_limit;
- png_alloc_size_t max_total;
-} store_pool;
-
-typedef struct png_store
-{
- /* For cexcept.h exception handling - simply store one of these;
- * the context is a self pointer but it may point to a different
- * png_store (in fact it never does in this program.)
- */
- struct exception_context
- exception_context;
-
- unsigned int verbose :1;
- unsigned int treat_warnings_as_errors :1;
- unsigned int expect_error :1;
- unsigned int expect_warning :1;
- unsigned int saw_warning :1;
- unsigned int speed :1;
- unsigned int progressive :1; /* use progressive read */
- unsigned int validated :1; /* used as a temporary flag */
- int nerrors;
- int nwarnings;
- char test[128]; /* Name of test */
- char error[256];
-
- /* Read fields */
- png_structp pread; /* Used to read a saved file */
- png_infop piread;
- png_store_file* current; /* Set when reading */
- png_store_buffer* next; /* Set when reading */
- png_size_t readpos; /* Position in *next */
- png_byte* image; /* Buffer for reading interlaced images */
- png_size_t cb_image; /* Size of this buffer */
- png_size_t cb_row; /* Row size of the image(s) */
- png_uint_32 image_h; /* Number of rows in a single image */
- store_pool read_memory_pool;
-
- /* Write fields */
- png_store_file* saved;
- png_structp pwrite; /* Used when writing a new file */
- png_infop piwrite;
- png_size_t writepos; /* Position in .new */
- char wname[FILE_NAME_SIZE];
- png_store_buffer new; /* The end of the new PNG file being written. */
- store_pool write_memory_pool;
- store_palette_entry* palette;
- int npalette;
-} png_store;
-
-/* Initialization and cleanup */
-static void
-store_pool_mark(png_bytep mark)
-{
- static png_uint_32 store_seed[2] = { 0x12345678, 1};
-
- make_four_random_bytes(store_seed, mark);
-}
-
-/* Use this for random 32 bit values; this function makes sure the result is
- * non-zero.
- */
-static png_uint_32
-random_32(void)
-{
-
- for(;;)
- {
- png_byte mark[4];
- png_uint_32 result;
-
- store_pool_mark(mark);
- result = png_get_uint_32(mark);
-
- if (result != 0)
- return result;
- }
-}
-
-static void
-store_pool_init(png_store *ps, store_pool *pool)
-{
- memset(pool, 0, sizeof *pool);
-
- pool->store = ps;
- pool->list = NULL;
- pool->max = pool->current = pool->limit = pool->total = 0;
- pool->max_max = pool->max_limit = pool->max_total = 0;
- store_pool_mark(pool->mark);
-}
-
-static void
-store_init(png_store* ps)
-{
- memset(ps, 0, sizeof *ps);
- init_exception_context(&ps->exception_context);
- store_pool_init(ps, &ps->read_memory_pool);
- store_pool_init(ps, &ps->write_memory_pool);
- ps->verbose = 0;
- ps->treat_warnings_as_errors = 0;
- ps->expect_error = 0;
- ps->expect_warning = 0;
- ps->saw_warning = 0;
- ps->speed = 0;
- ps->progressive = 0;
- ps->validated = 0;
- ps->nerrors = ps->nwarnings = 0;
- ps->pread = NULL;
- ps->piread = NULL;
- ps->saved = ps->current = NULL;
- ps->next = NULL;
- ps->readpos = 0;
- ps->image = NULL;
- ps->cb_image = 0;
- ps->cb_row = 0;
- ps->image_h = 0;
- ps->pwrite = NULL;
- ps->piwrite = NULL;
- ps->writepos = 0;
- ps->new.prev = NULL;
- ps->palette = NULL;
- ps->npalette = 0;
-}
-
-static void
-store_freebuffer(png_store_buffer* psb)
-{
- if (psb->prev)
- {
- store_freebuffer(psb->prev);
- free(psb->prev);
- psb->prev = NULL;
- }
-}
-
-static void
-store_freenew(png_store *ps)
-{
- store_freebuffer(&ps->new);
- ps->writepos = 0;
- if (ps->palette != NULL)
- {
- free(ps->palette);
- ps->palette = NULL;
- ps->npalette = 0;
- }
-}
-
-static void
-store_storenew(png_store *ps)
-{
- png_store_buffer *pb;
-
- if (ps->writepos != STORE_BUFFER_SIZE)
- png_error(ps->pwrite, "invalid store call");
-
- pb = voidcast(png_store_buffer*, malloc(sizeof *pb));
-
- if (pb == NULL)
- png_error(ps->pwrite, "store new: OOM");
-
- *pb = ps->new;
- ps->new.prev = pb;
- ps->writepos = 0;
-}
-
-static void
-store_freefile(png_store_file **ppf)
-{
- if (*ppf != NULL)
- {
- store_freefile(&(*ppf)->next);
-
- store_freebuffer(&(*ppf)->data);
- (*ppf)->datacount = 0;
- if ((*ppf)->palette != NULL)
- {
- free((*ppf)->palette);
- (*ppf)->palette = NULL;
- (*ppf)->npalette = 0;
- }
- free(*ppf);
- *ppf = NULL;
- }
-}
-
-/* Main interface to file storeage, after writing a new PNG file (see the API
- * below) call store_storefile to store the result with the given name and id.
- */
-static void
-store_storefile(png_store *ps, png_uint_32 id)
-{
- png_store_file *pf = voidcast(png_store_file*, malloc(sizeof *pf));
- if (pf == NULL)
- png_error(ps->pwrite, "storefile: OOM");
- safecat(pf->name, sizeof pf->name, 0, ps->wname);
- pf->id = id;
- pf->data = ps->new;
- pf->datacount = ps->writepos;
- ps->new.prev = NULL;
- ps->writepos = 0;
- pf->palette = ps->palette;
- pf->npalette = ps->npalette;
- ps->palette = 0;
- ps->npalette = 0;
-
- /* And save it. */
- pf->next = ps->saved;
- ps->saved = pf;
-}
-
-/* Generate an error message (in the given buffer) */
-static size_t
-store_message(png_store *ps, png_structp pp, char *buffer, size_t bufsize,
- size_t pos, PNG_CONST char *msg)
-{
- if (pp != NULL && pp == ps->pread)
- {
- /* Reading a file */
- pos = safecat(buffer, bufsize, pos, "read: ");
-
- if (ps->current != NULL)
- {
- pos = safecat(buffer, bufsize, pos, ps->current->name);
- pos = safecat(buffer, bufsize, pos, sep);
- }
- }
-
- else if (pp != NULL && pp == ps->pwrite)
- {
- /* Writing a file */
- pos = safecat(buffer, bufsize, pos, "write: ");
- pos = safecat(buffer, bufsize, pos, ps->wname);
- pos = safecat(buffer, bufsize, pos, sep);
- }
-
- else
- {
- /* Neither reading nor writing (or a memory error in struct delete) */
- pos = safecat(buffer, bufsize, pos, "pngvalid: ");
- }
-
- if (ps->test[0] != 0)
- {
- pos = safecat(buffer, bufsize, pos, ps->test);
- pos = safecat(buffer, bufsize, pos, sep);
- }
- pos = safecat(buffer, bufsize, pos, msg);
- return pos;
-}
-
-/* Verbose output to the error stream: */
-static void
-store_verbose(png_store *ps, png_structp pp, png_const_charp prefix,
- png_const_charp message)
-{
- char buffer[512];
-
- if (prefix)
- fputs(prefix, stderr);
-
- (void)store_message(ps, pp, buffer, sizeof buffer, 0, message);
- fputs(buffer, stderr);
- fputc('\n', stderr);
-}
-
-/* Log an error or warning - the relevant count is always incremented. */
-static void
-store_log(png_store* ps, png_structp pp, png_const_charp message, int is_error)
-{
- /* The warning is copied to the error buffer if there are no errors and it is
- * the first warning. The error is copied to the error buffer if it is the
- * first error (overwriting any prior warnings).
- */
- if (is_error ? (ps->nerrors)++ == 0 :
- (ps->nwarnings)++ == 0 && ps->nerrors == 0)
- store_message(ps, pp, ps->error, sizeof ps->error, 0, message);
-
- if (ps->verbose)
- store_verbose(ps, pp, is_error ? "error: " : "warning: ", message);
-}
-
-/* Functions to use as PNG callbacks. */
-static void
-store_error(png_structp pp, png_const_charp message) /* PNG_NORETURN */
-{
- png_store *ps = voidcast(png_store*, png_get_error_ptr(pp));
-
- if (!ps->expect_error)
- store_log(ps, pp, message, 1 /* error */);
-
- /* And finally throw an exception. */
- {
- struct exception_context *the_exception_context = &ps->exception_context;
- Throw ps;
- }
-}
-
-static void
-store_warning(png_structp pp, png_const_charp message)
-{
- png_store *ps = voidcast(png_store*, png_get_error_ptr(pp));
-
- if (!ps->expect_warning)
- store_log(ps, pp, message, 0 /* warning */);
- else
- ps->saw_warning = 1;
-}
-
-/* These somewhat odd functions are used when reading an image to ensure that
- * the buffer is big enough, the png_structp is for errors.
- */
-/* Return a single row from the correct image. */
-static png_bytep
-store_image_row(PNG_CONST png_store* ps, png_structp pp, int nImage,
- png_uint_32 y)
-{
- png_size_t coffset = (nImage * ps->image_h + y) * (ps->cb_row + 5) + 2;
-
- if (ps->image == NULL)
- png_error(pp, "no allocated image");
-
- if (coffset + ps->cb_row + 3 > ps->cb_image)
- png_error(pp, "image too small");
-
- return ps->image + coffset;
-}
-
-static void
-store_image_free(png_store *ps, png_structp pp)
-{
- if (ps->image != NULL)
- {
- png_bytep image = ps->image;
-
- if (image[-1] != 0xed || image[ps->cb_image] != 0xfe)
- {
- if (pp != NULL)
- png_error(pp, "png_store image overwrite (1)");
- else
- store_log(ps, NULL, "png_store image overwrite (2)", 1);
- }
-
- ps->image = NULL;
- ps->cb_image = 0;
- --image;
- free(image);
- }
-}
-
-static void
-store_ensure_image(png_store *ps, png_structp pp, int nImages, png_size_t cbRow,
- png_uint_32 cRows)
-{
- png_size_t cb = nImages * cRows * (cbRow + 5);
-
- if (ps->cb_image < cb)
- {
- png_bytep image;
-
- store_image_free(ps, pp);
-
- /* The buffer is deliberately mis-aligned. */
- image = voidcast(png_bytep, malloc(cb+2));
- if (image == NULL)
- {
- /* Called from the startup - ignore the error for the moment. */
- if (pp == NULL)
- return;
-
- png_error(pp, "OOM allocating image buffer");
- }
-
- /* These magic tags are used to detect overwrites above. */
- ++image;
- image[-1] = 0xed;
- image[cb] = 0xfe;
-
- ps->image = image;
- ps->cb_image = cb;
- }
-
- /* We have an adequate sized image; lay out the rows. There are 2 bytes at
- * the start and three at the end of each (this ensures that the row
- * alignment starts out odd - 2+1 and changes for larger images on each row.)
- */
- ps->cb_row = cbRow;
- ps->image_h = cRows;
-
- /* For error checking, the whole buffer is set to 10110010 (0xb2 - 178).
- * This deliberately doesn't match the bits in the size test image which are
- * outside the image; these are set to 0xff (all 1). To make the row
- * comparison work in the 'size' test case the size rows are pre-initialized
- * to the same value prior to calling 'standard_row'.
- */
- memset(ps->image, 178, cb);
-
- /* Then put in the marks. */
- while (--nImages >= 0)
- {
- png_uint_32 y;
-
- for (y=0; y<cRows; ++y)
- {
- png_bytep row = store_image_row(ps, pp, nImages, y);
-
- /* The markers: */
- row[-2] = 190;
- row[-1] = 239;
- row[cbRow] = 222;
- row[cbRow+1] = 173;
- row[cbRow+2] = 17;
- }
- }
-}
-
-static void
-store_image_check(PNG_CONST png_store* ps, png_structp pp, int iImage)
-{
- png_const_bytep image = ps->image;
-
- if (image[-1] != 0xed || image[ps->cb_image] != 0xfe)
- png_error(pp, "image overwrite");
- else
- {
- png_size_t cbRow = ps->cb_row;
- png_uint_32 rows = ps->image_h;
-
- image += iImage * (cbRow+5) * ps->image_h;
-
- image += 2; /* skip image first row markers */
-
- while (rows-- > 0)
- {
- if (image[-2] != 190 || image[-1] != 239)
- png_error(pp, "row start overwritten");
-
- if (image[cbRow] != 222 || image[cbRow+1] != 173 ||
- image[cbRow+2] != 17)
- png_error(pp, "row end overwritten");
-
- image += cbRow+5;
- }
- }
-}
-
-static void
-store_write(png_structp pp, png_bytep pb, png_size_t st)
-{
- png_store *ps = voidcast(png_store*, png_get_io_ptr(pp));
-
- if (ps->pwrite != pp)
- png_error(pp, "store state damaged");
-
- while (st > 0)
- {
- size_t cb;
-
- if (ps->writepos >= STORE_BUFFER_SIZE)
- store_storenew(ps);
-
- cb = st;
-
- if (cb > STORE_BUFFER_SIZE - ps->writepos)
- cb = STORE_BUFFER_SIZE - ps->writepos;
-
- memcpy(ps->new.buffer + ps->writepos, pb, cb);
- pb += cb;
- st -= cb;
- ps->writepos += cb;
- }
-}
-
-static void
-store_flush(png_structp pp)
-{
- UNUSED(pp) /*DOES NOTHING*/
-}
-
-static size_t
-store_read_buffer_size(png_store *ps)
-{
- /* Return the bytes available for read in the current buffer. */
- if (ps->next != &ps->current->data)
- return STORE_BUFFER_SIZE;
-
- return ps->current->datacount;
-}
-
-#ifdef PNG_READ_TRANSFORMS_SUPPORTED
-/* Return total bytes available for read. */
-static size_t
-store_read_buffer_avail(png_store *ps)
-{
- if (ps->current != NULL && ps->next != NULL)
- {
- png_store_buffer *next = &ps->current->data;
- size_t cbAvail = ps->current->datacount;
-
- while (next != ps->next && next != NULL)
- {
- next = next->prev;
- cbAvail += STORE_BUFFER_SIZE;
- }
-
- if (next != ps->next)
- png_error(ps->pread, "buffer read error");
-
- if (cbAvail > ps->readpos)
- return cbAvail - ps->readpos;
- }
-
- return 0;
-}
-#endif
-
-static int
-store_read_buffer_next(png_store *ps)
-{
- png_store_buffer *pbOld = ps->next;
- png_store_buffer *pbNew = &ps->current->data;
- if (pbOld != pbNew)
- {
- while (pbNew != NULL && pbNew->prev != pbOld)
- pbNew = pbNew->prev;
-
- if (pbNew != NULL)
- {
- ps->next = pbNew;
- ps->readpos = 0;
- return 1;
- }
-
- png_error(ps->pread, "buffer lost");
- }
-
- return 0; /* EOF or error */
-}
-
-/* Need separate implementation and callback to allow use of the same code
- * during progressive read, where the io_ptr is set internally by libpng.
- */
-static void
-store_read_imp(png_store *ps, png_bytep pb, png_size_t st)
-{
- if (ps->current == NULL || ps->next == NULL)
- png_error(ps->pread, "store state damaged");
-
- while (st > 0)
- {
- size_t cbAvail = store_read_buffer_size(ps) - ps->readpos;
-
- if (cbAvail > 0)
- {
- if (cbAvail > st) cbAvail = st;
- memcpy(pb, ps->next->buffer + ps->readpos, cbAvail);
- st -= cbAvail;
- pb += cbAvail;
- ps->readpos += cbAvail;
- }
-
- else if (!store_read_buffer_next(ps))
- png_error(ps->pread, "read beyond end of file");
- }
-}
-
-static void
-store_read(png_structp pp, png_bytep pb, png_size_t st)
-{
- png_store *ps = voidcast(png_store*, png_get_io_ptr(pp));
-
- if (ps == NULL || ps->pread != pp)
- png_error(pp, "bad store read call");
-
- store_read_imp(ps, pb, st);
-}
-
-static void
-store_progressive_read(png_store *ps, png_structp pp, png_infop pi)
-{
- /* Notice that a call to store_read will cause this function to fail because
- * readpos will be set.
- */
- if (ps->pread != pp || ps->current == NULL || ps->next == NULL)
- png_error(pp, "store state damaged (progressive)");
-
- do
- {
- if (ps->readpos != 0)
- png_error(pp, "store_read called during progressive read");
-
- png_process_data(pp, pi, ps->next->buffer, store_read_buffer_size(ps));
- }
- while (store_read_buffer_next(ps));
-}
-
-/* The caller must fill this in: */
-static store_palette_entry *
-store_write_palette(png_store *ps, int npalette)
-{
- if (ps->pwrite == NULL)
- store_log(ps, NULL, "attempt to write palette without write stream", 1);
-
- if (ps->palette != NULL)
- png_error(ps->pwrite, "multiple store_write_palette calls");
-
- /* This function can only return NULL if called with '0'! */
- if (npalette > 0)
- {
- ps->palette = voidcast(store_palette_entry*, malloc(npalette *
- sizeof *ps->palette));
-
- if (ps->palette == NULL)
- png_error(ps->pwrite, "store new palette: OOM");
-
- ps->npalette = npalette;
- }
-
- return ps->palette;
-}
-
-static store_palette_entry *
-store_current_palette(png_store *ps, int *npalette)
-{
- /* This is an internal error (the call has been made outside a read
- * operation.)
- */
- if (ps->current == NULL)
- store_log(ps, ps->pread, "no current stream for palette", 1);
-
- /* The result may be null if there is no palette. */
- *npalette = ps->current->npalette;
- return ps->current->palette;
-}
-
-/***************************** MEMORY MANAGEMENT*** ***************************/
-/* A store_memory is simply the header for an allocated block of memory. The
- * pointer returned to libpng is just after the end of the header block, the
- * allocated memory is followed by a second copy of the 'mark'.
- */
-typedef struct store_memory
-{
- store_pool *pool; /* Originating pool */
- struct store_memory *next; /* Singly linked list */
- png_alloc_size_t size; /* Size of memory allocated */
- png_byte mark[4]; /* ID marker */
-} store_memory;
-
-/* Handle a fatal error in memory allocation. This calls png_error if the
- * libpng struct is non-NULL, else it outputs a message and returns. This means
- * that a memory problem while libpng is running will abort (png_error) the
- * handling of particular file while one in cleanup (after the destroy of the
- * struct has returned) will simply keep going and free (or attempt to free)
- * all the memory.
- */
-static void
-store_pool_error(png_store *ps, png_structp pp, PNG_CONST char *msg)
-{
- if (pp != NULL)
- png_error(pp, msg);
-
- /* Else we have to do it ourselves. png_error eventually calls store_log,
- * above. store_log accepts a NULL png_structp - it just changes what gets
- * output by store_message.
- */
- store_log(ps, pp, msg, 1 /* error */);
-}
-
-static void
-store_memory_free(png_structp pp, store_pool *pool, store_memory *memory)
-{
- /* Note that pp may be NULL (see store_pool_delete below), the caller has
- * found 'memory' in pool->list *and* unlinked this entry, so this is a valid
- * pointer (for sure), but the contents may have been trashed.
- */
- if (memory->pool != pool)
- store_pool_error(pool->store, pp, "memory corrupted (pool)");
-
- else if (memcmp(memory->mark, pool->mark, sizeof memory->mark) != 0)
- store_pool_error(pool->store, pp, "memory corrupted (start)");
-
- /* It should be safe to read the size field now. */
- else
- {
- png_alloc_size_t cb = memory->size;
-
- if (cb > pool->max)
- store_pool_error(pool->store, pp, "memory corrupted (size)");
-
- else if (memcmp((png_bytep)(memory+1)+cb, pool->mark, sizeof pool->mark)
- != 0)
- store_pool_error(pool->store, pp, "memory corrupted (end)");
-
- /* Finally give the library a chance to find problems too: */
- else
- {
- pool->current -= cb;
- free(memory);
- }
- }
-}
-
-static void
-store_pool_delete(png_store *ps, store_pool *pool)
-{
- if (pool->list != NULL)
- {
- fprintf(stderr, "%s: %s %s: memory lost (list follows):\n", ps->test,
- pool == &ps->read_memory_pool ? "read" : "write",
- pool == &ps->read_memory_pool ? (ps->current != NULL ?
- ps->current->name : "unknown file") : ps->wname);
- ++ps->nerrors;
-
- do
- {
- store_memory *next = pool->list;
- pool->list = next->next;
- next->next = NULL;
-
- fprintf(stderr, "\t%lu bytes @ %p\n",
- (unsigned long)next->size, (PNG_CONST void*)(next+1));
- /* The NULL means this will always return, even if the memory is
- * corrupted.
- */
- store_memory_free(NULL, pool, next);
- }
- while (pool->list != NULL);
- }
-
- /* And reset the other fields too for the next time. */
- if (pool->max > pool->max_max) pool->max_max = pool->max;
- pool->max = 0;
- if (pool->current != 0) /* unexpected internal error */
- fprintf(stderr, "%s: %s %s: memory counter mismatch (internal error)\n",
- ps->test, pool == &ps->read_memory_pool ? "read" : "write",
- pool == &ps->read_memory_pool ? (ps->current != NULL ?
- ps->current->name : "unknown file") : ps->wname);
- pool->current = 0;
-
- if (pool->limit > pool->max_limit)
- pool->max_limit = pool->limit;
-
- pool->limit = 0;
-
- if (pool->total > pool->max_total)
- pool->max_total = pool->total;
-
- pool->total = 0;
-
- /* Get a new mark too. */
- store_pool_mark(pool->mark);
-}
-
-/* The memory callbacks: */
-static png_voidp
-store_malloc(png_structp pp, png_alloc_size_t cb)
-{
- store_pool *pool = voidcast(store_pool*, png_get_mem_ptr(pp));
- store_memory *new = voidcast(store_memory*, malloc(cb + (sizeof *new) +
- (sizeof pool->mark)));
-
- if (new != NULL)
- {
- if (cb > pool->max)
- pool->max = cb;
-
- pool->current += cb;
-
- if (pool->current > pool->limit)
- pool->limit = pool->current;
-
- pool->total += cb;
-
- new->size = cb;
- memcpy(new->mark, pool->mark, sizeof new->mark);
- memcpy((png_byte*)(new+1) + cb, pool->mark, sizeof pool->mark);
- new->pool = pool;
- new->next = pool->list;
- pool->list = new;
- ++new;
- }
-
- else
- store_pool_error(pool->store, pp, "out of memory");
-
- return new;
-}
-
-static void
-store_free(png_structp pp, png_voidp memory)
-{
- store_pool *pool = voidcast(store_pool*, png_get_mem_ptr(pp));
- store_memory *this = voidcast(store_memory*, memory), **test;
-
- /* First check that this 'memory' really is valid memory - it must be in the
- * pool list. If it is, use the shared memory_free function to free it.
- */
- --this;
- for (test = &pool->list; *test != this; test = &(*test)->next)
- {
- if (*test == NULL)
- {
- store_pool_error(pool->store, pp, "bad pointer to free");
- return;
- }
- }
-
- /* Unlink this entry, *test == this. */
- *test = this->next;
- this->next = NULL;
- store_memory_free(pp, pool, this);
-}
-
-/* Setup functions. */
-/* Cleanup when aborting a write or after storing the new file. */
-static void
-store_write_reset(png_store *ps)
-{
- if (ps->pwrite != NULL)
- {
- anon_context(ps);
-
- Try
- png_destroy_write_struct(&ps->pwrite, &ps->piwrite);
-
- Catch_anonymous
- {
- /* memory corruption: continue. */
- }
-
- ps->pwrite = NULL;
- ps->piwrite = NULL;
- }
-
- /* And make sure that all the memory has been freed - this will output
- * spurious errors in the case of memory corruption above, but this is safe.
- */
- store_pool_delete(ps, &ps->write_memory_pool);
-
- store_freenew(ps);
-}
-
-/* The following is the main write function, it returns a png_struct and,
- * optionally, a png_info suitable for writiing a new PNG file. Use
- * store_storefile above to record this file after it has been written. The
- * returned libpng structures as destroyed by store_write_reset above.
- */
-static png_structp
-set_store_for_write(png_store *ps, png_infopp ppi,
- PNG_CONST char * volatile name)
-{
- anon_context(ps);
-
- Try
- {
- if (ps->pwrite != NULL)
- png_error(ps->pwrite, "write store already in use");
-
- store_write_reset(ps);
- safecat(ps->wname, sizeof ps->wname, 0, name);
-
- /* Don't do the slow memory checks if doing a speed test. */
- if (ps->speed)
- ps->pwrite = png_create_write_struct(PNG_LIBPNG_VER_STRING,
- ps, store_error, store_warning);
-
- else
- ps->pwrite = png_create_write_struct_2(PNG_LIBPNG_VER_STRING,
- ps, store_error, store_warning, &ps->write_memory_pool,
- store_malloc, store_free);
-
- png_set_write_fn(ps->pwrite, ps, store_write, store_flush);
-
- if (ppi != NULL)
- *ppi = ps->piwrite = png_create_info_struct(ps->pwrite);
- }
-
- Catch_anonymous
- return NULL;
-
- return ps->pwrite;
-}
-
-/* Cleanup when finished reading (either due to error or in the success case).
- */
-static void
-store_read_reset(png_store *ps)
-{
- if (ps->pread != NULL)
- {
- anon_context(ps);
-
- Try
- png_destroy_read_struct(&ps->pread, &ps->piread, NULL);
-
- Catch_anonymous
- {
- /* error already output: continue */
- }
-
- ps->pread = NULL;
- ps->piread = NULL;
- }
-
- /* Always do this to be safe. */
- store_pool_delete(ps, &ps->read_memory_pool);
-
- ps->current = NULL;
- ps->next = NULL;
- ps->readpos = 0;
- ps->validated = 0;
-}
-
-static void
-store_read_set(png_store *ps, png_uint_32 id)
-{
- png_store_file *pf = ps->saved;
-
- while (pf != NULL)
- {
- if (pf->id == id)
- {
- ps->current = pf;
- ps->next = NULL;
- store_read_buffer_next(ps);
- return;
- }
-
- pf = pf->next;
- }
-
- {
- size_t pos;
- char msg[FILE_NAME_SIZE+64];
-
- pos = standard_name_from_id(msg, sizeof msg, 0, id);
- pos = safecat(msg, sizeof msg, pos, ": file not found");
- png_error(ps->pread, msg);
- }
-}
-
-/* The main interface for reading a saved file - pass the id number of the file
- * to retrieve. Ids must be unique or the earlier file will be hidden. The API
- * returns a png_struct and, optionally, a png_info. Both of these will be
- * destroyed by store_read_reset above.
- */
-static png_structp
-set_store_for_read(png_store *ps, png_infopp ppi, png_uint_32 id,
- PNG_CONST char *name)
-{
- /* Set the name for png_error */
- safecat(ps->test, sizeof ps->test, 0, name);
-
- if (ps->pread != NULL)
- png_error(ps->pread, "read store already in use");
-
- store_read_reset(ps);
-
- /* Both the create APIs can return NULL if used in their default mode
- * (because there is no other way of handling an error because the jmp_buf
- * by default is stored in png_struct and that has not been allocated!)
- * However, given that store_error works correctly in these circumstances
- * we don't ever expect NULL in this program.
- */
- if (ps->speed)
- ps->pread = png_create_read_struct(PNG_LIBPNG_VER_STRING, ps,
- store_error, store_warning);
-
- else
- ps->pread = png_create_read_struct_2(PNG_LIBPNG_VER_STRING, ps,
- store_error, store_warning, &ps->read_memory_pool, store_malloc,
- store_free);
-
- if (ps->pread == NULL)
- {
- struct exception_context *the_exception_context = &ps->exception_context;
-
- store_log(ps, NULL, "png_create_read_struct returned NULL (unexpected)",
- 1 /*error*/);
-
- Throw ps;
- }
-
- store_read_set(ps, id);
-
- if (ppi != NULL)
- *ppi = ps->piread = png_create_info_struct(ps->pread);
-
- return ps->pread;
-}
-
-/* The overall cleanup of a store simply calls the above then removes all the
- * saved files. This does not delete the store itself.
- */
-static void
-store_delete(png_store *ps)
-{
- store_write_reset(ps);
- store_read_reset(ps);
- store_freefile(&ps->saved);
- store_image_free(ps, NULL);
-}
-
-/*********************** PNG FILE MODIFICATION ON READ ************************/
-/* Files may be modified on read. The following structure contains a complete
- * png_store together with extra members to handle modification and a special
- * read callback for libpng. To use this the 'modifications' field must be set
- * to a list of png_modification structures that actually perform the
- * modification, otherwise a png_modifier is functionally equivalent to a
- * png_store. There is a special read function, set_modifier_for_read, which
- * replaces set_store_for_read.
- */
-typedef enum modifier_state
-{
- modifier_start, /* Initial value */
- modifier_signature, /* Have a signature */
- modifier_IHDR /* Have an IHDR */
-} modifier_state;
-
-typedef struct CIE_color
-{
- /* A single CIE tristimulus value, representing the unique response of a
- * standard observer to a variety of light spectra. The observer recognizes
- * all spectra that produce this response as the same color, therefore this
- * is effectively a description of a color.
- */
- double X, Y, Z;
-} CIE_color;
-
-static double
-chromaticity_x(CIE_color c)
-{
- return c.X / (c.X + c.Y + c.Z);
-}
-
-static double
-chromaticity_y(CIE_color c)
-{
- return c.Y / (c.X + c.Y + c.Z);
-}
-
-typedef struct color_encoding
-{
- /* A description of an (R,G,B) encoding of color (as defined above); this
- * includes the actual colors of the (R,G,B) triples (1,0,0), (0,1,0) and
- * (0,0,1) plus an encoding value that is used to encode the linear
- * components R, G and B to give the actual values R^gamma, G^gamma and
- * B^gamma that are stored.
- */
- double gamma; /* Encoding (file) gamma of space */
- CIE_color red, green, blue; /* End points */
-} color_encoding;
-
-static CIE_color
-white_point(PNG_CONST color_encoding *encoding)
-{
- CIE_color white;
-
- white.X = encoding->red.X + encoding->green.X + encoding->blue.X;
- white.Y = encoding->red.Y + encoding->green.Y + encoding->blue.Y;
- white.Z = encoding->red.Z + encoding->green.Z + encoding->blue.Z;
-
- return white;
-}
-
-static void
-normalize_color_encoding(color_encoding *encoding)
-{
- PNG_CONST double whiteY = encoding->red.Y + encoding->green.Y +
- encoding->blue.Y;
-
- if (whiteY != 1)
- {
- encoding->red.X /= whiteY;
- encoding->red.Y /= whiteY;
- encoding->red.Z /= whiteY;
- encoding->green.X /= whiteY;
- encoding->green.Y /= whiteY;
- encoding->green.Z /= whiteY;
- encoding->blue.X /= whiteY;
- encoding->blue.Y /= whiteY;
- encoding->blue.Z /= whiteY;
- }
-}
-
-static size_t
-safecat_color_encoding(char *buffer, size_t bufsize, size_t pos,
- PNG_CONST color_encoding *e, double encoding_gamma)
-{
- if (e != 0)
- {
- if (encoding_gamma != 0)
- pos = safecat(buffer, bufsize, pos, "(");
- pos = safecat(buffer, bufsize, pos, "R(");
- pos = safecatd(buffer, bufsize, pos, e->red.X, 4);
- pos = safecat(buffer, bufsize, pos, ",");
- pos = safecatd(buffer, bufsize, pos, e->red.Y, 4);
- pos = safecat(buffer, bufsize, pos, ",");
- pos = safecatd(buffer, bufsize, pos, e->red.Z, 4);
- pos = safecat(buffer, bufsize, pos, "),G(");
- pos = safecatd(buffer, bufsize, pos, e->green.X, 4);
- pos = safecat(buffer, bufsize, pos, ",");
- pos = safecatd(buffer, bufsize, pos, e->green.Y, 4);
- pos = safecat(buffer, bufsize, pos, ",");
- pos = safecatd(buffer, bufsize, pos, e->green.Z, 4);
- pos = safecat(buffer, bufsize, pos, "),B(");
- pos = safecatd(buffer, bufsize, pos, e->blue.X, 4);
- pos = safecat(buffer, bufsize, pos, ",");
- pos = safecatd(buffer, bufsize, pos, e->blue.Y, 4);
- pos = safecat(buffer, bufsize, pos, ",");
- pos = safecatd(buffer, bufsize, pos, e->blue.Z, 4);
- pos = safecat(buffer, bufsize, pos, ")");
- if (encoding_gamma != 0)
- pos = safecat(buffer, bufsize, pos, ")");
- }
-
- if (encoding_gamma != 0)
- {
- pos = safecat(buffer, bufsize, pos, "^");
- pos = safecatd(buffer, bufsize, pos, encoding_gamma, 5);
- }
-
- return pos;
-}
-
-typedef struct png_modifier
-{
- png_store this; /* I am a png_store */
- struct png_modification *modifications; /* Changes to make */
-
- modifier_state state; /* My state */
-
- /* Information from IHDR: */
- png_byte bit_depth; /* From IHDR */
- png_byte colour_type; /* From IHDR */
-
- /* While handling PLTE, IDAT and IEND these chunks may be pended to allow
- * other chunks to be inserted.
- */
- png_uint_32 pending_len;
- png_uint_32 pending_chunk;
-
- /* Test values */
- double *gammas;
- unsigned int ngammas;
- unsigned int ngamma_tests; /* Number of gamma tests to run*/
- double current_gamma; /* 0 if not set */
- PNG_CONST color_encoding *encodings;
- unsigned int nencodings;
- PNG_CONST color_encoding *current_encoding; /* If an encoding has been set */
- unsigned int encoding_counter; /* For iteration */
- int encoding_ignored; /* Something overwrote it */
-
- /* Control variables used to iterate through possible encodings, the
- * following must be set to 0 and tested by the function that uses the
- * png_modifier because the modifier only sets it to 1 (true.)
- */
- unsigned int repeat :1; /* Repeat this transform test. */
- unsigned int test_uses_encoding :1;
-
- /* Lowest sbit to test (libpng fails for sbit < 8) */
- png_byte sbitlow;
-
- /* Error control - these are the limits on errors accepted by the gamma tests
- * below.
- */
- double maxout8; /* Maximum output value error */
- double maxabs8; /* Absolute sample error 0..1 */
- double maxcalc8; /* Absolute sample error 0..1 */
- double maxpc8; /* Percentage sample error 0..100% */
- double maxout16; /* Maximum output value error */
- double maxabs16; /* Absolute sample error 0..1 */
- double maxcalc16;/* Absolute sample error 0..1 */
- double maxpc16; /* Percentage sample error 0..100% */
-
- /* This is set by transforms that need to allow a higher limit, it is an
- * internal check on pngvalid to ensure that the calculated error limits are
- * not ridiculous; without this it is too easy to make a mistake in pngvalid
- * that allows any value through.
- */
- double limit; /* limit on error values, normally 4E-3 */
-
- /* Log limits - values above this are logged, but not necessarily
- * warned.
- */
- double log8; /* Absolute error in 8 bits to log */
- double log16; /* Absolute error in 16 bits to log */
-
- /* Logged 8 and 16 bit errors ('output' values): */
- double error_gray_2;
- double error_gray_4;
- double error_gray_8;
- double error_gray_16;
- double error_color_8;
- double error_color_16;
- double error_indexed;
-
- /* Flags: */
- /* Whether to call png_read_update_info, not png_read_start_image, and how
- * many times to call it.
- */
- int use_update_info;
-
- /* Whether or not to interlace. */
- int interlace_type :9; /* int, but must store '1' */
-
- /* Run the standard tests? */
- unsigned int test_standard :1;
-
- /* Run the odd-sized image and interlace read/write tests? */
- unsigned int test_size :1;
-
- /* Run tests on reading with a combiniation of transforms, */
- unsigned int test_transform :1;
-
- /* When to use the use_input_precision option: */
- unsigned int use_input_precision :1;
- unsigned int use_input_precision_sbit :1;
- unsigned int use_input_precision_16to8 :1;
-
- /* If set assume that the calculation bit depth is set by the input
- * precision, not the output precision.
- */
- unsigned int calculations_use_input_precision :1;
-
- /* If set assume that the calculations are done in 16 bits even if both input
- * and output are 8 bit or less.
- */
- unsigned int assume_16_bit_calculations :1;
-
- /* Which gamma tests to run: */
- unsigned int test_gamma_threshold :1;
- unsigned int test_gamma_transform :1; /* main tests */
- unsigned int test_gamma_sbit :1;
- unsigned int test_gamma_scale16 :1;
- unsigned int test_gamma_background :1;
- unsigned int test_gamma_alpha_mode :1;
- unsigned int test_gamma_expand16 :1;
- unsigned int test_exhaustive :1;
-
- unsigned int log :1; /* Log max error */
-
- /* Buffer information, the buffer size limits the size of the chunks that can
- * be modified - they must fit (including header and CRC) into the buffer!
- */
- size_t flush; /* Count of bytes to flush */
- size_t buffer_count; /* Bytes in buffer */
- size_t buffer_position; /* Position in buffer */
- png_byte buffer[1024];
-} png_modifier;
-
-/* This returns true if the test should be stopped now because it has already
- * failed and it is running silently.
- */
-static int fail(png_modifier *pm)
-{
- return !pm->log && !pm->this.verbose && (pm->this.nerrors > 0 ||
- (pm->this.treat_warnings_as_errors && pm->this.nwarnings > 0));
-}
-
-static void
-modifier_init(png_modifier *pm)
-{
- memset(pm, 0, sizeof *pm);
- store_init(&pm->this);
- pm->modifications = NULL;
- pm->state = modifier_start;
- pm->sbitlow = 1U;
- pm->ngammas = 0;
- pm->ngamma_tests = 0;
- pm->gammas = 0;
- pm->current_gamma = 0;
- pm->encodings = 0;
- pm->nencodings = 0;
- pm->current_encoding = 0;
- pm->encoding_counter = 0;
- pm->encoding_ignored = 0;
- pm->repeat = 0;
- pm->test_uses_encoding = 0;
- pm->maxout8 = pm->maxpc8 = pm->maxabs8 = pm->maxcalc8 = 0;
- pm->maxout16 = pm->maxpc16 = pm->maxabs16 = pm->maxcalc16 = 0;
- pm->limit = 4E-3;
- pm->log8 = pm->log16 = 0; /* Means 'off' */
- pm->error_gray_2 = pm->error_gray_4 = pm->error_gray_8 = 0;
- pm->error_gray_16 = pm->error_color_8 = pm->error_color_16 = 0;
- pm->error_indexed = 0;
- pm->use_update_info = 0;
- pm->interlace_type = PNG_INTERLACE_NONE;
- pm->test_standard = 0;
- pm->test_size = 0;
- pm->test_transform = 0;
- pm->use_input_precision = 0;
- pm->use_input_precision_sbit = 0;
- pm->use_input_precision_16to8 = 0;
- pm->calculations_use_input_precision = 0;
- pm->test_gamma_threshold = 0;
- pm->test_gamma_transform = 0;
- pm->test_gamma_sbit = 0;
- pm->test_gamma_scale16 = 0;
- pm->test_gamma_background = 0;
- pm->test_gamma_alpha_mode = 0;
- pm->test_gamma_expand16 = 0;
- pm->test_exhaustive = 0;
- pm->log = 0;
-
- /* Rely on the memset for all the other fields - there are no pointers */
-}
-
-#ifdef PNG_READ_TRANSFORMS_SUPPORTED
-/* If pm->calculations_use_input_precision is set then operations will happen
- * with only 8 bit precision unless both the input and output bit depth are 16.
- *
- * If pm->assume_16_bit_calculations is set then even 8 bit calculations use 16
- * bit precision. This only affects those of the following limits that pertain
- * to a calculation - not a digitization operation - unless the following API is
- * called directly.
- */
-static double digitize(PNG_CONST png_modifier *pm, double value,
- int sample_depth, int do_round)
-{
- /* 'value' is in the range 0 to 1, the result is the same value rounded to a
- * multiple of the digitization factor - 8 or 16 bits depending on both the
- * sample depth and the 'assume' setting. Digitization is normally by
- * rounding and 'do_round' should be 1, if it is 0 the digitized value will
- * be truncated.
- */
- PNG_CONST unsigned int digitization_factor =
- (pm->assume_16_bit_calculations || sample_depth == 16) ? 65535 : 255;
-
- /* Limiting the range is done as a convenience to the caller - it's easier to
- * do it once here than every time at the call site.
- */
- if (value <= 0)
- value = 0;
- else if (value >= 1)
- value = 1;
-
- value *= digitization_factor;
- if (do_round) value += .5;
- return floor(value)/digitization_factor;
-}
-
-static double abserr(PNG_CONST png_modifier *pm, int in_depth, int out_depth)
-{
- /* Absolute error permitted in linear values - affected by the bit depth of
- * the calculations.
- */
- if (pm->assume_16_bit_calculations || (out_depth == 16 && (in_depth == 16 ||
- !pm->calculations_use_input_precision)))
- return pm->maxabs16;
- else
- return pm->maxabs8;
-}
-
-static double calcerr(PNG_CONST png_modifier *pm, int in_depth, int out_depth)
-{
- /* Error in the linear composition arithmetic - only relevant when
- * composition actually happens (0 < alpha < 1).
- */
- if (pm->assume_16_bit_calculations || (out_depth == 16 && (in_depth == 16 ||
- !pm->calculations_use_input_precision)))
- return pm->maxcalc16;
- else
- return pm->maxcalc8;
-}
-
-static double pcerr(PNG_CONST png_modifier *pm, int in_depth, int out_depth)
-{
- /* Percentage error permitted in the linear values. Note that the specified
- * value is a percentage but this routine returns a simple number.
- */
- if (pm->assume_16_bit_calculations || (out_depth == 16 && (in_depth == 16 ||
- !pm->calculations_use_input_precision)))
- return pm->maxpc16 * .01;
- else
- return pm->maxpc8 * .01;
-}
-
-/* Output error - the error in the encoded value. This is determined by the
- * digitization of the output so can be +/-0.5 in the actual output value. In
- * the expand_16 case with the current code in libpng the expand happens after
- * all the calculations are done in 8 bit arithmetic, so even though the output
- * depth is 16 the output error is determined by the 8 bit calculation.
- *
- * This limit is not determined by the bit depth of internal calculations.
- *
- * The specified parameter does *not* include the base .5 digitization error but
- * it is added here.
- */
-static double outerr(PNG_CONST png_modifier *pm, int in_depth, int out_depth)
-{
- /* There is a serious error in the 2 and 4 bit grayscale transform because
- * the gamma table value (8 bits) is simply shifted, not rounded, so the
- * error in 4 bit grayscale gamma is up to the value below. This is a hack
- * to allow pngvalid to succeed:
- *
- * TODO: fix this in libpng
- */
- if (out_depth == 2)
- return .73182-.5;
-
- if (out_depth == 4)
- return .90644-.5;
-
- if (out_depth == 16 && (in_depth == 16 ||
- !pm->calculations_use_input_precision))
- return pm->maxout16;
-
- /* This is the case where the value was calculated at 8-bit precision then
- * scaled to 16 bits.
- */
- else if (out_depth == 16)
- return pm->maxout8 * 257;
-
- else
- return pm->maxout8;
-}
-
-/* This does the same thing as the above however it returns the value to log,
- * rather than raising a warning. This is useful for debugging to track down
- * exactly what set of parameters cause high error values.
- */
-static double outlog(PNG_CONST png_modifier *pm, int in_depth, int out_depth)
-{
- /* The command line parameters are either 8 bit (0..255) or 16 bit (0..65535)
- * and so must be adjusted for low bit depth grayscale:
- */
- if (out_depth <= 8)
- {
- if (pm->log8 == 0) /* switched off */
- return 256;
-
- if (out_depth < 8)
- return pm->log8 / 255 * ((1<<out_depth)-1);
-
- return pm->log8;
- }
-
- if (out_depth == 16 && (in_depth == 16 ||
- !pm->calculations_use_input_precision))
- {
- if (pm->log16 == 0)
- return 65536;
-
- return pm->log16;
- }
-
- /* This is the case where the value was calculated at 8-bit precision then
- * scaled to 16 bits.
- */
- if (pm->log8 == 0)
- return 65536;
-
- return pm->log8 * 257;
-}
-
-/* This complements the above by providing the appropriate quantization for the
- * final value. Normally this would just be quantization to an integral value,
- * but in the 8 bit calculation case it's actually quantization to a multiple of
- * 257!
- */
-static int output_quantization_factor(PNG_CONST png_modifier *pm, int in_depth,
- int out_depth)
-{
- if (out_depth == 16 && in_depth != 16
- && pm->calculations_use_input_precision)
- return 257;
- else
- return 1;
-}
-
-/* One modification structure must be provided for each chunk to be modified (in
- * fact more than one can be provided if multiple separate changes are desired
- * for a single chunk.) Modifications include adding a new chunk when a
- * suitable chunk does not exist.
- *
- * The caller of modify_fn will reset the CRC of the chunk and record 'modified'
- * or 'added' as appropriate if the modify_fn returns 1 (true). If the
- * modify_fn is NULL the chunk is simply removed.
- */
-typedef struct png_modification
-{
- struct png_modification *next;
- png_uint_32 chunk;
-
- /* If the following is NULL all matching chunks will be removed: */
- int (*modify_fn)(struct png_modifier *pm,
- struct png_modification *me, int add);
-
- /* If the following is set to PLTE, IDAT or IEND and the chunk has not been
- * found and modified (and there is a modify_fn) the modify_fn will be called
- * to add the chunk before the relevant chunk.
- */
- png_uint_32 add;
- unsigned int modified :1; /* Chunk was modified */
- unsigned int added :1; /* Chunk was added */
- unsigned int removed :1; /* Chunk was removed */
-} png_modification;
-
-static void
-modification_reset(png_modification *pmm)
-{
- if (pmm != NULL)
- {
- pmm->modified = 0;
- pmm->added = 0;
- pmm->removed = 0;
- modification_reset(pmm->next);
- }
-}
-
-static void
-modification_init(png_modification *pmm)
-{
- memset(pmm, 0, sizeof *pmm);
- pmm->next = NULL;
- pmm->chunk = 0;
- pmm->modify_fn = NULL;
- pmm->add = 0;
- modification_reset(pmm);
-}
-
-static void
-modifier_current_encoding(PNG_CONST png_modifier *pm, color_encoding *ce)
-{
- if (pm->current_encoding != 0)
- *ce = *pm->current_encoding;
-
- else
- memset(ce, 0, sizeof *ce);
-
- ce->gamma = pm->current_gamma;
-}
-
-static size_t
-safecat_current_encoding(char *buffer, size_t bufsize, size_t pos,
- PNG_CONST png_modifier *pm)
-{
- pos = safecat_color_encoding(buffer, bufsize, pos, pm->current_encoding,
- pm->current_gamma);
-
- if (pm->encoding_ignored)
- pos = safecat(buffer, bufsize, pos, "[overridden]");
-
- return pos;
-}
-
-/* Iterate through the usefully testable color encodings. An encoding is one
- * of:
- *
- * 1) Nothing (no color space, no gamma).
- * 2) Just a gamma value from the gamma array (including 1.0)
- * 3) A color space from the encodings array with the corresponding gamma.
- * 4) The same, but with gamma 1.0 (only really useful with 16 bit calculations)
- *
- * The iterator selects these in turn, the randomizer selects one at random,
- * which is used depends on the setting of the 'test_exhaustive' flag. Notice
- * that this function changes the colour space encoding so it must only be
- * called on completion of the previous test. This is what 'modifier_reset'
- * does, below.
- *
- * After the function has been called the 'repeat' flag will still be set; the
- * caller of modifier_reset must reset it at the start of each run of the test!
- */
-static unsigned int
-modifier_total_encodings(PNG_CONST png_modifier *pm)
-{
- return 1 + /* (1) nothing */
- pm->ngammas + /* (2) gamma values to test */
- pm->nencodings + /* (3) total number of encodings */
- /* The following test only works after the first time through the
- * png_modifier code because 'bit_depth' is set when the IHDR is read.
- * modifier_reset, below, preserves the setting until after it has called
- * the iterate function (also below.)
- *
- * For this reason do not rely on this function outside a call to
- * modifier_reset.
- */
- ((pm->bit_depth == 16 || pm->assume_16_bit_calculations) ?
- pm->nencodings : 0); /* (4) encodings with gamma == 1.0 */
-}
-
-static void
-modifier_encoding_iterate(png_modifier *pm)
-{
- if (!pm->repeat && /* Else something needs the current encoding again. */
- pm->test_uses_encoding) /* Some transform is encoding dependent */
- {
- if (pm->test_exhaustive)
- {
- if (++pm->encoding_counter >= modifier_total_encodings(pm))
- pm->encoding_counter = 0; /* This will stop the repeat */
- }
-
- else
- {
- /* Not exhaustive - choose an encoding at random; generate a number in
- * the range 1..(max-1), so the result is always non-zero:
- */
- if (pm->encoding_counter == 0)
- pm->encoding_counter = random_mod(modifier_total_encodings(pm)-1)+1;
- else
- pm->encoding_counter = 0;
- }
-
- if (pm->encoding_counter > 0)
- pm->repeat = 1;
- }
-
- else if (!pm->repeat)
- pm->encoding_counter = 0;
-}
-
-static void
-modifier_reset(png_modifier *pm)
-{
- store_read_reset(&pm->this);
- pm->limit = 4E-3;
- pm->pending_len = pm->pending_chunk = 0;
- pm->flush = pm->buffer_count = pm->buffer_position = 0;
- pm->modifications = NULL;
- pm->state = modifier_start;
- modifier_encoding_iterate(pm);
- /* The following must be set in the next run. In particular
- * test_uses_encodings must be set in the _ini function of each transform
- * that looks at the encodings. (Not the 'add' function!)
- */
- pm->test_uses_encoding = 0;
- pm->current_gamma = 0;
- pm->current_encoding = 0;
- pm->encoding_ignored = 0;
- /* These only become value after IHDR is read: */
- pm->bit_depth = pm->colour_type = 0;
-}
-
-/* The following must be called before anything else to get the encoding set up
- * on the modifier. In particular it must be called before the transform init
- * functions are called.
- */
-static void
-modifier_set_encoding(png_modifier *pm)
-{
- /* Set the encoding to the one specified by the current encoding counter,
- * first clear out all the settings - this corresponds to an encoding_counter
- * of 0.
- */
- pm->current_gamma = 0;
- pm->current_encoding = 0;
- pm->encoding_ignored = 0; /* not ignored yet - happens in _ini functions. */
-
- /* Now, if required, set the gamma and encoding fields. */
- if (pm->encoding_counter > 0)
- {
- /* The gammas[] array is an array of screen gammas, not encoding gammas,
- * so we need the inverse:
- */
- if (pm->encoding_counter <= pm->ngammas)
- pm->current_gamma = 1/pm->gammas[pm->encoding_counter-1];
-
- else
- {
- unsigned int i = pm->encoding_counter - pm->ngammas;
-
- if (i >= pm->nencodings)
- {
- i %= pm->nencodings;
- pm->current_gamma = 1; /* Linear, only in the 16 bit case */
- }
-
- else
- pm->current_gamma = pm->encodings[i].gamma;
-
- pm->current_encoding = pm->encodings + i;
- }
- }
-}
-
-/* Enquiry functions to find out what is set. Notice that there is an implicit
- * assumption below that the first encoding in the list is the one for sRGB.
- */
-static int
-modifier_color_encoding_is_sRGB(PNG_CONST png_modifier *pm)
-{
- return pm->current_encoding != 0 && pm->current_encoding == pm->encodings &&
- pm->current_encoding->gamma == pm->current_gamma;
-}
-
-static int
-modifier_color_encoding_is_set(PNG_CONST png_modifier *pm)
-{
- return pm->current_gamma != 0;
-}
-
-/* Convenience macros. */
-#define CHUNK(a,b,c,d) (((a)<<24)+((b)<<16)+((c)<<8)+(d))
-#define CHUNK_IHDR CHUNK(73,72,68,82)
-#define CHUNK_PLTE CHUNK(80,76,84,69)
-#define CHUNK_IDAT CHUNK(73,68,65,84)
-#define CHUNK_IEND CHUNK(73,69,78,68)
-#define CHUNK_cHRM CHUNK(99,72,82,77)
-#define CHUNK_gAMA CHUNK(103,65,77,65)
-#define CHUNK_sBIT CHUNK(115,66,73,84)
-#define CHUNK_sRGB CHUNK(115,82,71,66)
-
-/* The guts of modification are performed during a read. */
-static void
-modifier_crc(png_bytep buffer)
-{
- /* Recalculate the chunk CRC - a complete chunk must be in
- * the buffer, at the start.
- */
- uInt datalen = png_get_uint_32(buffer);
- uLong crc = crc32(0, buffer+4, datalen+4);
- /* The cast to png_uint_32 is safe because a crc32 is always a 32 bit value.
- */
- png_save_uint_32(buffer+datalen+8, (png_uint_32)crc);
-}
-
-static void
-modifier_setbuffer(png_modifier *pm)
-{
- modifier_crc(pm->buffer);
- pm->buffer_count = png_get_uint_32(pm->buffer)+12;
- pm->buffer_position = 0;
-}
-
-/* Separate the callback into the actual implementation (which is passed the
- * png_modifier explicitly) and the callback, which gets the modifier from the
- * png_struct.
- */
-static void
-modifier_read_imp(png_modifier *pm, png_bytep pb, png_size_t st)
-{
- while (st > 0)
- {
- size_t cb;
- png_uint_32 len, chunk;
- png_modification *mod;
-
- if (pm->buffer_position >= pm->buffer_count) switch (pm->state)
- {
- static png_byte sign[8] = { 137, 80, 78, 71, 13, 10, 26, 10 };
- case modifier_start:
- store_read_imp(&pm->this, pm->buffer, 8); /* size of signature. */
- pm->buffer_count = 8;
- pm->buffer_position = 0;
-
- if (memcmp(pm->buffer, sign, 8) != 0)
- png_error(pm->this.pread, "invalid PNG file signature");
- pm->state = modifier_signature;
- break;
-
- case modifier_signature:
- store_read_imp(&pm->this, pm->buffer, 13+12); /* size of IHDR */
- pm->buffer_count = 13+12;
- pm->buffer_position = 0;
-
- if (png_get_uint_32(pm->buffer) != 13 ||
- png_get_uint_32(pm->buffer+4) != CHUNK_IHDR)
- png_error(pm->this.pread, "invalid IHDR");
-
- /* Check the list of modifiers for modifications to the IHDR. */
- mod = pm->modifications;
- while (mod != NULL)
- {
- if (mod->chunk == CHUNK_IHDR && mod->modify_fn &&
- (*mod->modify_fn)(pm, mod, 0))
- {
- mod->modified = 1;
- modifier_setbuffer(pm);
- }
-
- /* Ignore removal or add if IHDR! */
- mod = mod->next;
- }
-
- /* Cache information from the IHDR (the modified one.) */
- pm->bit_depth = pm->buffer[8+8];
- pm->colour_type = pm->buffer[8+8+1];
-
- pm->state = modifier_IHDR;
- pm->flush = 0;
- break;
-
- case modifier_IHDR:
- default:
- /* Read a new chunk and process it until we see PLTE, IDAT or
- * IEND. 'flush' indicates that there is still some data to
- * output from the preceding chunk.
- */
- if ((cb = pm->flush) > 0)
- {
- if (cb > st) cb = st;
- pm->flush -= cb;
- store_read_imp(&pm->this, pb, cb);
- pb += cb;
- st -= cb;
- if (st == 0) return;
- }
-
- /* No more bytes to flush, read a header, or handle a pending
- * chunk.
- */
- if (pm->pending_chunk != 0)
- {
- png_save_uint_32(pm->buffer, pm->pending_len);
- png_save_uint_32(pm->buffer+4, pm->pending_chunk);
- pm->pending_len = 0;
- pm->pending_chunk = 0;
- }
- else
- store_read_imp(&pm->this, pm->buffer, 8);
-
- pm->buffer_count = 8;
- pm->buffer_position = 0;
-
- /* Check for something to modify or a terminator chunk. */
- len = png_get_uint_32(pm->buffer);
- chunk = png_get_uint_32(pm->buffer+4);
-
- /* Terminators first, they may have to be delayed for added
- * chunks
- */
- if (chunk == CHUNK_PLTE || chunk == CHUNK_IDAT ||
- chunk == CHUNK_IEND)
- {
- mod = pm->modifications;
-
- while (mod != NULL)
- {
- if ((mod->add == chunk ||
- (mod->add == CHUNK_PLTE && chunk == CHUNK_IDAT)) &&
- mod->modify_fn != NULL && !mod->modified && !mod->added)
- {
- /* Regardless of what the modify function does do not run
- * this again.
- */
- mod->added = 1;
-
- if ((*mod->modify_fn)(pm, mod, 1 /*add*/))
- {
- /* Reset the CRC on a new chunk */
- if (pm->buffer_count > 0)
- modifier_setbuffer(pm);
-
- else
- {
- pm->buffer_position = 0;
- mod->removed = 1;
- }
-
- /* The buffer has been filled with something (we assume)
- * so output this. Pend the current chunk.
- */
- pm->pending_len = len;
- pm->pending_chunk = chunk;
- break; /* out of while */
- }
- }
-
- mod = mod->next;
- }
-
- /* Don't do any further processing if the buffer was modified -
- * otherwise the code will end up modifying a chunk that was
- * just added.
- */
- if (mod != NULL)
- break; /* out of switch */
- }
-
- /* If we get to here then this chunk may need to be modified. To
- * do this it must be less than 1024 bytes in total size, otherwise
- * it just gets flushed.
- */
- if (len+12 <= sizeof pm->buffer)
- {
- store_read_imp(&pm->this, pm->buffer+pm->buffer_count,
- len+12-pm->buffer_count);
- pm->buffer_count = len+12;
-
- /* Check for a modification, else leave it be. */
- mod = pm->modifications;
- while (mod != NULL)
- {
- if (mod->chunk == chunk)
- {
- if (mod->modify_fn == NULL)
- {
- /* Remove this chunk */
- pm->buffer_count = pm->buffer_position = 0;
- mod->removed = 1;
- break; /* Terminate the while loop */
- }
-
- else if ((*mod->modify_fn)(pm, mod, 0))
- {
- mod->modified = 1;
- /* The chunk may have been removed: */
- if (pm->buffer_count == 0)
- {
- pm->buffer_position = 0;
- break;
- }
- modifier_setbuffer(pm);
- }
- }
-
- mod = mod->next;
- }
- }
-
- else
- pm->flush = len+12 - pm->buffer_count; /* data + crc */
-
- /* Take the data from the buffer (if there is any). */
- break;
- }
-
- /* Here to read from the modifier buffer (not directly from
- * the store, as in the flush case above.)
- */
- cb = pm->buffer_count - pm->buffer_position;
-
- if (cb > st)
- cb = st;
-
- memcpy(pb, pm->buffer + pm->buffer_position, cb);
- st -= cb;
- pb += cb;
- pm->buffer_position += cb;
- }
-}
-
-/* The callback: */
-static void
-modifier_read(png_structp pp, png_bytep pb, png_size_t st)
-{
- png_modifier *pm = voidcast(png_modifier*, png_get_io_ptr(pp));
-
- if (pm == NULL || pm->this.pread != pp)
- png_error(pp, "bad modifier_read call");
-
- modifier_read_imp(pm, pb, st);
-}
-
-/* Like store_progressive_read but the data is getting changed as we go so we
- * need a local buffer.
- */
-static void
-modifier_progressive_read(png_modifier *pm, png_structp pp, png_infop pi)
-{
- if (pm->this.pread != pp || pm->this.current == NULL ||
- pm->this.next == NULL)
- png_error(pp, "store state damaged (progressive)");
-
- /* This is another Horowitz and Hill random noise generator. In this case
- * the aim is to stress the progressive reader with truly horrible variable
- * buffer sizes in the range 1..500, so a sequence of 9 bit random numbers
- * is generated. We could probably just count from 1 to 32767 and get as
- * good a result.
- */
- for (;;)
- {
- static png_uint_32 noise = 1;
- png_size_t cb, cbAvail;
- png_byte buffer[512];
-
- /* Generate 15 more bits of stuff: */
- noise = (noise << 9) | ((noise ^ (noise >> (9-5))) & 0x1ff);
- cb = noise & 0x1ff;
-
- /* Check that this number of bytes are available (in the current buffer.)
- * (This doesn't quite work - the modifier might delete a chunk; unlikely
- * but possible, it doesn't happen at present because the modifier only
- * adds chunks to standard images.)
- */
- cbAvail = store_read_buffer_avail(&pm->this);
- if (pm->buffer_count > pm->buffer_position)
- cbAvail += pm->buffer_count - pm->buffer_position;
-
- if (cb > cbAvail)
- {
- /* Check for EOF: */
- if (cbAvail == 0)
- break;
-
- cb = cbAvail;
- }
-
- modifier_read_imp(pm, buffer, cb);
- png_process_data(pp, pi, buffer, cb);
- }
-
- /* Check the invariants at the end (if this fails it's a problem in this
- * file!)
- */
- if (pm->buffer_count > pm->buffer_position ||
- pm->this.next != &pm->this.current->data ||
- pm->this.readpos < pm->this.current->datacount)
- png_error(pp, "progressive read implementation error");
-}
-
-/* Set up a modifier. */
-static png_structp
-set_modifier_for_read(png_modifier *pm, png_infopp ppi, png_uint_32 id,
- PNG_CONST char *name)
-{
- /* Do this first so that the modifier fields are cleared even if an error
- * happens allocating the png_struct. No allocation is done here so no
- * cleanup is required.
- */
- pm->state = modifier_start;
- pm->bit_depth = 0;
- pm->colour_type = 255;
-
- pm->pending_len = 0;
- pm->pending_chunk = 0;
- pm->flush = 0;
- pm->buffer_count = 0;
- pm->buffer_position = 0;
-
- return set_store_for_read(&pm->this, ppi, id, name);
-}
-
-
-/******************************** MODIFICATIONS *******************************/
-/* Standard modifications to add chunks. These do not require the _SUPPORTED
- * macros because the chunks can be there regardless of whether this specific
- * libpng supports them.
- */
-typedef struct gama_modification
-{
- png_modification this;
- png_fixed_point gamma;
-} gama_modification;
-
-static int
-gama_modify(png_modifier *pm, png_modification *me, int add)
-{
- UNUSED(add)
- /* This simply dumps the given gamma value into the buffer. */
- png_save_uint_32(pm->buffer, 4);
- png_save_uint_32(pm->buffer+4, CHUNK_gAMA);
- png_save_uint_32(pm->buffer+8, ((gama_modification*)me)->gamma);
- return 1;
-}
-
-static void
-gama_modification_init(gama_modification *me, png_modifier *pm, double gammad)
-{
- double g;
-
- modification_init(&me->this);
- me->this.chunk = CHUNK_gAMA;
- me->this.modify_fn = gama_modify;
- me->this.add = CHUNK_PLTE;
- g = fix(gammad);
- me->gamma = (png_fixed_point)g;
- me->this.next = pm->modifications;
- pm->modifications = &me->this;
-}
-
-typedef struct chrm_modification
-{
- png_modification this;
- PNG_CONST color_encoding *encoding;
- png_fixed_point wx, wy, rx, ry, gx, gy, bx, by;
-} chrm_modification;
-
-static int
-chrm_modify(png_modifier *pm, png_modification *me, int add)
-{
- UNUSED(add)
- /* As with gAMA this just adds the required cHRM chunk to the buffer. */
- png_save_uint_32(pm->buffer , 32);
- png_save_uint_32(pm->buffer+ 4, CHUNK_cHRM);
- png_save_uint_32(pm->buffer+ 8, ((chrm_modification*)me)->wx);
- png_save_uint_32(pm->buffer+12, ((chrm_modification*)me)->wy);
- png_save_uint_32(pm->buffer+16, ((chrm_modification*)me)->rx);
- png_save_uint_32(pm->buffer+20, ((chrm_modification*)me)->ry);
- png_save_uint_32(pm->buffer+24, ((chrm_modification*)me)->gx);
- png_save_uint_32(pm->buffer+28, ((chrm_modification*)me)->gy);
- png_save_uint_32(pm->buffer+32, ((chrm_modification*)me)->bx);
- png_save_uint_32(pm->buffer+36, ((chrm_modification*)me)->by);
- return 1;
-}
-
-static void
-chrm_modification_init(chrm_modification *me, png_modifier *pm,
- PNG_CONST color_encoding *encoding)
-{
- CIE_color white = white_point(encoding);
-
- /* Original end points: */
- me->encoding = encoding;
-
- /* Chromaticities (in fixed point): */
- me->wx = fix(chromaticity_x(white));
- me->wy = fix(chromaticity_y(white));
-
- me->rx = fix(chromaticity_x(encoding->red));
- me->ry = fix(chromaticity_y(encoding->red));
- me->gx = fix(chromaticity_x(encoding->green));
- me->gy = fix(chromaticity_y(encoding->green));
- me->bx = fix(chromaticity_x(encoding->blue));
- me->by = fix(chromaticity_y(encoding->blue));
-
- modification_init(&me->this);
- me->this.chunk = CHUNK_cHRM;
- me->this.modify_fn = chrm_modify;
- me->this.add = CHUNK_PLTE;
- me->this.next = pm->modifications;
- pm->modifications = &me->this;
-}
-
-typedef struct srgb_modification
-{
- png_modification this;
- png_byte intent;
-} srgb_modification;
-
-static int
-srgb_modify(png_modifier *pm, png_modification *me, int add)
-{
- UNUSED(add)
- /* As above, ignore add and just make a new chunk */
- png_save_uint_32(pm->buffer, 1);
- png_save_uint_32(pm->buffer+4, CHUNK_sRGB);
- pm->buffer[8] = ((srgb_modification*)me)->intent;
- return 1;
-}
-
-static void
-srgb_modification_init(srgb_modification *me, png_modifier *pm, png_byte intent)
-{
- modification_init(&me->this);
- me->this.chunk = CHUNK_sBIT;
-
- if (intent <= 3) /* if valid, else *delete* sRGB chunks */
- {
- me->this.modify_fn = srgb_modify;
- me->this.add = CHUNK_PLTE;
- me->intent = intent;
- }
-
- else
- {
- me->this.modify_fn = 0;
- me->this.add = 0;
- me->intent = 0;
- }
-
- me->this.next = pm->modifications;
- pm->modifications = &me->this;
-}
-
-typedef struct sbit_modification
-{
- png_modification this;
- png_byte sbit;
-} sbit_modification;
-
-static int
-sbit_modify(png_modifier *pm, png_modification *me, int add)
-{
- png_byte sbit = ((sbit_modification*)me)->sbit;
- if (pm->bit_depth > sbit)
- {
- int cb = 0;
- switch (pm->colour_type)
- {
- case 0:
- cb = 1;
- break;
-
- case 2:
- case 3:
- cb = 3;
- break;
-
- case 4:
- cb = 2;
- break;
-
- case 6:
- cb = 4;
- break;
-
- default:
- png_error(pm->this.pread,
- "unexpected colour type in sBIT modification");
- }
-
- png_save_uint_32(pm->buffer, cb);
- png_save_uint_32(pm->buffer+4, CHUNK_sBIT);
-
- while (cb > 0)
- (pm->buffer+8)[--cb] = sbit;
-
- return 1;
- }
- else if (!add)
- {
- /* Remove the sBIT chunk */
- pm->buffer_count = pm->buffer_position = 0;
- return 1;
- }
- else
- return 0; /* do nothing */
-}
-
-static void
-sbit_modification_init(sbit_modification *me, png_modifier *pm, png_byte sbit)
-{
- modification_init(&me->this);
- me->this.chunk = CHUNK_sBIT;
- me->this.modify_fn = sbit_modify;
- me->this.add = CHUNK_PLTE;
- me->sbit = sbit;
- me->this.next = pm->modifications;
- pm->modifications = &me->this;
-}
-#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
-
-/***************************** STANDARD PNG FILES *****************************/
-/* Standard files - write and save standard files. */
-/* There are two basic forms of standard images. Those which attempt to have
- * all the possible pixel values (not possible for 16bpp images, but a range of
- * values are produced) and those which have a range of image sizes. The former
- * are used for testing transforms, in particular gamma correction and bit
- * reduction and increase. The latter are reserved for testing the behavior of
- * libpng with respect to 'odd' image sizes - particularly small images where
- * rows become 1 byte and interlace passes disappear.
- *
- * The first, most useful, set are the 'transform' images, the second set of
- * small images are the 'size' images.
- *
- * The transform files are constructed with rows which fit into a 1024 byte row
- * buffer. This makes allocation easier below. Further regardless of the file
- * format every row has 128 pixels (giving 1024 bytes for 64bpp formats).
- *
- * Files are stored with no gAMA or sBIT chunks, with a PLTE only when needed
- * and with an ID derived from the colour type, bit depth and interlace type
- * as above (FILEID). The width (128) and height (variable) are not stored in
- * the FILEID - instead the fields are set to 0, indicating a transform file.
- *
- * The size files ar constructed with rows a maximum of 128 bytes wide, allowing
- * a maximum width of 16 pixels (for the 64bpp case.) They also have a maximum
- * height of 16 rows. The width and height are stored in the FILEID and, being
- * non-zero, indicate a size file.
- *
- * For palette image (colour type 3) multiple transform images are stored with
- * the same bit depth to allow testing of more colour combinations -
- * particularly important for testing the gamma code because libpng uses a
- * different code path for palette images. For size images a single palette is
- * used.
- */
-
-/* Make a 'standard' palette. Because there are only 256 entries in a palette
- * (maximum) this actually makes a random palette in the hope that enough tests
- * will catch enough errors. (Note that the same palette isn't produced every
- * time for the same test - it depends on what previous tests have been run -
- * but a given set of arguments to pngvalid will always produce the same palette
- * at the same test! This is why pseudo-random number generators are useful for
- * testing.)
- *
- * The store must be open for write when this is called, otherwise an internal
- * error will occur. This routine contains its own magic number seed, so the
- * palettes generated don't change if there are intervening errors (changing the
- * calls to the store_mark seed.)
- */
-static store_palette_entry *
-make_standard_palette(png_store* ps, int npalette, int do_tRNS)
-{
- static png_uint_32 palette_seed[2] = { 0x87654321, 9 };
-
- int i = 0;
- png_byte values[256][4];
-
- /* Always put in black and white plus the six primary and secondary colors.
- */
- for (; i<8; ++i)
- {
- values[i][1] = (i&1) ? 255 : 0;
- values[i][2] = (i&2) ? 255 : 0;
- values[i][3] = (i&4) ? 255 : 0;
- }
-
- /* Then add 62 grays (one quarter of the remaining 256 slots). */
- {
- int j = 0;
- png_byte random_bytes[4];
- png_byte need[256];
-
- need[0] = 0; /*got black*/
- memset(need+1, 1, (sizeof need)-2); /*need these*/
- need[255] = 0; /*but not white*/
-
- while (i<70)
- {
- png_byte b;
-
- if (j==0)
- {
- make_four_random_bytes(palette_seed, random_bytes);
- j = 4;
- }
-
- b = random_bytes[--j];
- if (need[b])
- {
- values[i][1] = b;
- values[i][2] = b;
- values[i++][3] = b;
- }
- }
- }
-
- /* Finally add 192 colors at random - don't worry about matches to things we
- * already have, chance is less than 1/65536. Don't worry about grays,
- * chance is the same, so we get a duplicate or extra gray less than 1 time
- * in 170.
- */
- for (; i<256; ++i)
- make_four_random_bytes(palette_seed, values[i]);
-
- /* Fill in the alpha values in the first byte. Just use all possible values
- * (0..255) in an apparently random order:
- */
- {
- store_palette_entry *palette;
- png_byte selector[4];
-
- make_four_random_bytes(palette_seed, selector);
-
- if (do_tRNS)
- for (i=0; i<256; ++i)
- values[i][0] = (png_byte)(i ^ selector[0]);
-
- else
- for (i=0; i<256; ++i)
- values[i][0] = 255; /* no transparency/tRNS chunk */
-
- /* 'values' contains 256 ARGB values, but we only need 'npalette'.
- * 'npalette' will always be a power of 2: 2, 4, 16 or 256. In the low
- * bit depth cases select colors at random, else it is difficult to have
- * a set of low bit depth palette test with any chance of a reasonable
- * range of colors. Do this by randomly permuting values into the low
- * 'npalette' entries using an XOR mask generated here. This also
- * permutes the npalette == 256 case in a potentially useful way (there is
- * no relationship between palette index and the color value therein!)
- */
- palette = store_write_palette(ps, npalette);
-
- for (i=0; i<npalette; ++i)
- {
- palette[i].alpha = values[i ^ selector[1]][0];
- palette[i].red = values[i ^ selector[1]][1];
- palette[i].green = values[i ^ selector[1]][2];
- palette[i].blue = values[i ^ selector[1]][3];
- }
-
- return palette;
- }
-}
-
-/* Initialize a standard palette on a write stream. The 'do_tRNS' argument
- * indicates whether or not to also set the tRNS chunk.
- */
-static void
-init_standard_palette(png_store *ps, png_structp pp, png_infop pi, int npalette,
- int do_tRNS)
-{
- store_palette_entry *ppal = make_standard_palette(ps, npalette, do_tRNS);
-
- {
- int i;
- png_color palette[256];
-
- /* Set all entries to detect overread errors. */
- for (i=0; i<npalette; ++i)
- {
- palette[i].red = ppal[i].red;
- palette[i].green = ppal[i].green;
- palette[i].blue = ppal[i].blue;
- }
-
- /* Just in case fill in the rest with detectable values: */
- for (; i<256; ++i)
- palette[i].red = palette[i].green = palette[i].blue = 42;
-
- png_set_PLTE(pp, pi, palette, npalette);
- }
-
- if (do_tRNS)
- {
- int i, j;
- png_byte tRNS[256];
-
- /* Set all the entries, but skip trailing opaque entries */
- for (i=j=0; i<npalette; ++i)
- if ((tRNS[i] = ppal[i].alpha) < 255)
- j = i+1;
-
- /* Fill in the remainder with a detectable value: */
- for (; i<256; ++i)
- tRNS[i] = 24;
-
- if (j > 0)
- png_set_tRNS(pp, pi, tRNS, j, 0/*color*/);
- }
-}
-
-/* The number of passes is related to the interlace type. There was no libpng
- * API to determine this prior to 1.5, so we need an inquiry function:
- */
-static int
-npasses_from_interlace_type(png_structp pp, int interlace_type)
-{
- switch (interlace_type)
- {
- default:
- png_error(pp, "invalid interlace type");
-
- case PNG_INTERLACE_NONE:
- return 1;
-
- case PNG_INTERLACE_ADAM7:
- return PNG_INTERLACE_ADAM7_PASSES;
- }
-}
-
-static unsigned int
-bit_size(png_structp pp, png_byte colour_type, png_byte bit_depth)
-{
- switch (colour_type)
- {
- default: png_error(pp, "invalid color type");
-
- case 0: return bit_depth;
-
- case 2: return 3*bit_depth;
-
- case 3: return bit_depth;
-
- case 4: return 2*bit_depth;
-
- case 6: return 4*bit_depth;
- }
-}
-
-#define TRANSFORM_WIDTH 128U
-#define TRANSFORM_ROWMAX (TRANSFORM_WIDTH*8U)
-#define SIZE_ROWMAX (16*8U) /* 16 pixels, max 8 bytes each - 128 bytes */
-#define STANDARD_ROWMAX TRANSFORM_ROWMAX /* The larger of the two */
-#define SIZE_HEIGHTMAX 16 /* Maximum range of size images */
-
-static size_t
-transform_rowsize(png_structp pp, png_byte colour_type, png_byte bit_depth)
-{
- return (TRANSFORM_WIDTH * bit_size(pp, colour_type, bit_depth)) / 8;
-}
-
-/* transform_width(pp, colour_type, bit_depth) current returns the same number
- * every time, so just use a macro:
- */
-#define transform_width(pp, colour_type, bit_depth) TRANSFORM_WIDTH
-
-static png_uint_32
-transform_height(png_structp pp, png_byte colour_type, png_byte bit_depth)
-{
- switch (bit_size(pp, colour_type, bit_depth))
- {
- case 1:
- case 2:
- case 4:
- return 1; /* Total of 128 pixels */
-
- case 8:
- return 2; /* Total of 256 pixels/bytes */
-
- case 16:
- return 512; /* Total of 65536 pixels */
-
- case 24:
- case 32:
- return 512; /* 65536 pixels */
-
- case 48:
- case 64:
- return 2048;/* 4 x 65536 pixels. */
-# define TRANSFORM_HEIGHTMAX 2048
-
- default:
- return 0; /* Error, will be caught later */
- }
-}
-
-/* The following can only be defined here, now we have the definitions
- * of the transform image sizes.
- */
-static png_uint_32
-standard_width(png_structp pp, png_uint_32 id)
-{
- png_uint_32 width = WIDTH_FROM_ID(id);
- UNUSED(pp)
-
- if (width == 0)
- width = transform_width(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id));
-
- return width;
-}
-
-static png_uint_32
-standard_height(png_structp pp, png_uint_32 id)
-{
- png_uint_32 height = HEIGHT_FROM_ID(id);
-
- if (height == 0)
- height = transform_height(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id));
-
- return height;
-}
-
-static png_uint_32
-standard_rowsize(png_structp pp, png_uint_32 id)
-{
- png_uint_32 width = standard_width(pp, id);
-
- /* This won't overflow: */
- width *= bit_size(pp, COL_FROM_ID(id), DEPTH_FROM_ID(id));
- return (width + 7) / 8;
-}
-
-static void
-transform_row(png_structp pp, png_byte buffer[TRANSFORM_ROWMAX],
- png_byte colour_type, png_byte bit_depth, png_uint_32 y)
-{
- png_uint_32 v = y << 7;
- png_uint_32 i = 0;
-
- switch (bit_size(pp, colour_type, bit_depth))
- {
- case 1:
- while (i<128/8) buffer[i] = v & 0xff, v += 17, ++i;
- return;
-
- case 2:
- while (i<128/4) buffer[i] = v & 0xff, v += 33, ++i;
- return;
-
- case 4:
- while (i<128/2) buffer[i] = v & 0xff, v += 65, ++i;
- return;
-
- case 8:
- /* 256 bytes total, 128 bytes in each row set as follows: */
- while (i<128) buffer[i] = v & 0xff, ++v, ++i;
- return;
-
- case 16:
- /* Generate all 65536 pixel values in order, which includes the 8 bit
- * GA case as well as the 16 bit G case.
- */
- while (i<128)
- buffer[2*i] = (v>>8) & 0xff, buffer[2*i+1] = v & 0xff, ++v, ++i;
-
- return;
-
- case 24:
- /* 65535 pixels, but rotate the values. */
- while (i<128)
- {
- /* Three bytes per pixel, r, g, b, make b by r^g */
- buffer[3*i+0] = (v >> 8) & 0xff;
- buffer[3*i+1] = v & 0xff;
- buffer[3*i+2] = ((v >> 8) ^ v) & 0xff;
- ++v;
- ++i;
- }
-
- return;
-
- case 32:
- /* 65535 pixels, r, g, b, a; just replicate */
- while (i<128)
- {
- buffer[4*i+0] = (v >> 8) & 0xff;
- buffer[4*i+1] = v & 0xff;
- buffer[4*i+2] = (v >> 8) & 0xff;
- buffer[4*i+3] = v & 0xff;
- ++v;
- ++i;
- }
-
- return;
-
- case 48:
- /* y is maximum 2047, giving 4x65536 pixels, make 'r' increase by 1 at
- * each pixel, g increase by 257 (0x101) and 'b' by 0x1111:
- */
- while (i<128)
- {
- png_uint_32 t = v++;
- buffer[6*i+0] = (t >> 8) & 0xff;
- buffer[6*i+1] = t & 0xff;
- t *= 257;
- buffer[6*i+2] = (t >> 8) & 0xff;
- buffer[6*i+3] = t & 0xff;
- t *= 17;
- buffer[6*i+4] = (t >> 8) & 0xff;
- buffer[6*i+5] = t & 0xff;
- ++i;
- }
-
- return;
-
- case 64:
- /* As above in the 32 bit case. */
- while (i<128)
- {
- png_uint_32 t = v++;
- buffer[8*i+0] = (t >> 8) & 0xff;
- buffer[8*i+1] = t & 0xff;
- buffer[8*i+4] = (t >> 8) & 0xff;
- buffer[8*i+5] = t & 0xff;
- t *= 257;
- buffer[8*i+2] = (t >> 8) & 0xff;
- buffer[8*i+3] = t & 0xff;
- buffer[8*i+6] = (t >> 8) & 0xff;
- buffer[8*i+7] = t & 0xff;
- ++i;
- }
- return;
-
- default:
- break;
- }
-
- png_error(pp, "internal error");
-}
-
-/* This is just to do the right cast - could be changed to a function to check
- * 'bd' but there isn't much point.
- */
-#define DEPTH(bd) ((png_byte)(1U << (bd)))
-
-/* Make a standardized image given a an image colour type, bit depth and
- * interlace type. The standard images have a very restricted range of
- * rows and heights and are used for testing transforms rather than image
- * layout details. See make_size_images below for a way to make images
- * that test odd sizes along with the libpng interlace handling.
- */
-static void
-make_transform_image(png_store* PNG_CONST ps, png_byte PNG_CONST colour_type,
- png_byte PNG_CONST bit_depth, int palette_number, int interlace_type,
- png_const_charp name)
-{
- context(ps, fault);
-
- Try
- {
- png_infop pi;
- png_structp pp = set_store_for_write(ps, &pi, name);
- png_uint_32 h;
-
- /* In the event of a problem return control to the Catch statement below
- * to do the clean up - it is not possible to 'return' directly from a Try
- * block.
- */
- if (pp == NULL)
- Throw ps;
-
- h = transform_height(pp, colour_type, bit_depth);
-
- png_set_IHDR(pp, pi, transform_width(pp, colour_type, bit_depth), h,
- bit_depth, colour_type, interlace_type,
- PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
-
-#ifdef PNG_TEXT_SUPPORTED
- {
- static char key[] = "image name"; /* must be writeable */
- size_t pos;
- png_text text;
- char copy[FILE_NAME_SIZE];
-
- /* Use a compressed text string to test the correct interaction of text
- * compression and IDAT compression.
- */
- text.compression = PNG_TEXT_COMPRESSION_zTXt;
- text.key = key;
- /* Yuck: the text must be writable! */
- pos = safecat(copy, sizeof copy, 0, ps->wname);
- text.text = copy;
- text.text_length = pos;
- text.itxt_length = 0;
- text.lang = 0;
- text.lang_key = 0;
-
- png_set_text(pp, pi, &text, 1);
- }
-#endif
-
- if (colour_type == 3) /* palette */
- init_standard_palette(ps, pp, pi, 1U << bit_depth, 1/*do tRNS*/);
-
- png_write_info(pp, pi);
-
- if (png_get_rowbytes(pp, pi) !=
- transform_rowsize(pp, colour_type, bit_depth))
- png_error(pp, "row size incorrect");
-
- else
- {
- /* Somewhat confusingly this must be called *after* png_write_info
- * because if it is called before, the information in *pp has not been
- * updated to reflect the interlaced image.
- */
- int npasses = png_set_interlace_handling(pp);
- int pass;
-
- if (npasses != npasses_from_interlace_type(pp, interlace_type))
- png_error(pp, "write: png_set_interlace_handling failed");
-
- for (pass=0; pass<npasses; ++pass)
- {
- png_uint_32 y;
-
- for (y=0; y<h; ++y)
- {
- png_byte buffer[TRANSFORM_ROWMAX];
-
- transform_row(pp, buffer, colour_type, bit_depth, y);
- png_write_row(pp, buffer);
- }
- }
- }
-
-#ifdef PNG_TEXT_SUPPORTED
- {
- static char key[] = "end marker";
- static char comment[] = "end";
- png_text text;
-
- /* Use a compressed text string to test the correct interaction of text
- * compression and IDAT compression.
- */
- text.compression = PNG_TEXT_COMPRESSION_zTXt;
- text.key = key;
- text.text = comment;
- text.text_length = (sizeof comment)-1;
- text.itxt_length = 0;
- text.lang = 0;
- text.lang_key = 0;
-
- png_set_text(pp, pi, &text, 1);
- }
-#endif
-
- png_write_end(pp, pi);
-
- /* And store this under the appropriate id, then clean up. */
- store_storefile(ps, FILEID(colour_type, bit_depth, palette_number,
- interlace_type, 0, 0, 0));
-
- store_write_reset(ps);
- }
-
- Catch(fault)
- {
- /* Use the png_store returned by the exception. This may help the compiler
- * because 'ps' is not used in this branch of the setjmp. Note that fault
- * and ps will always be the same value.
- */
- store_write_reset(fault);
- }
-}
-
-static void
-make_transform_images(png_store *ps)
-{
- png_byte colour_type = 0;
- png_byte bit_depth = 0;
- int palette_number = 0;
-
- /* This is in case of errors. */
- safecat(ps->test, sizeof ps->test, 0, "make standard images");
-
- /* Use next_format to enumerate all the combinations we test, including
- * generating multiple low bit depth palette images.
- */
- while (next_format(&colour_type, &bit_depth, &palette_number))
- {
- int interlace_type;
-
- for (interlace_type = PNG_INTERLACE_NONE;
- interlace_type < PNG_INTERLACE_LAST; ++interlace_type)
- {
- char name[FILE_NAME_SIZE];
-
- standard_name(name, sizeof name, 0, colour_type, bit_depth,
- palette_number, interlace_type, 0, 0, 0);
- make_transform_image(ps, colour_type, bit_depth, palette_number,
- interlace_type, name);
- }
- }
-}
-
-/* The following two routines use the PNG interlace support macros from
- * png.h to interlace or deinterlace rows.
- */
-static void
-interlace_row(png_bytep buffer, png_const_bytep imageRow,
- unsigned int pixel_size, png_uint_32 w, int pass)
-{
- png_uint_32 xin, xout, xstep;
-
- /* Note that this can, trivially, be optimized to a memcpy on pass 7, the
- * code is presented this way to make it easier to understand. In practice
- * consult the code in the libpng source to see other ways of doing this.
- */
- xin = PNG_PASS_START_COL(pass);
- xstep = 1U<<PNG_PASS_COL_SHIFT(pass);
-
- for (xout=0; xin<w; xin+=xstep)
- {
- pixel_copy(buffer, xout, imageRow, xin, pixel_size);
- ++xout;
- }
-}
-
-static void
-deinterlace_row(png_bytep buffer, png_const_bytep row,
- unsigned int pixel_size, png_uint_32 w, int pass)
-{
- /* The inverse of the above, 'row' is part of row 'y' of the output image,
- * in 'buffer'. The image is 'w' wide and this is pass 'pass', distribute
- * the pixels of row into buffer and return the number written (to allow
- * this to be checked).
- */
- png_uint_32 xin, xout, xstep;
-
- xout = PNG_PASS_START_COL(pass);
- xstep = 1U<<PNG_PASS_COL_SHIFT(pass);
-
- for (xin=0; xout<w; xout+=xstep)
- {
- pixel_copy(buffer, xout, row, xin, pixel_size);
- ++xin;
- }
-}
-
-/* Build a single row for the 'size' test images; this fills in only the
- * first bit_width bits of the sample row.
- */
-static void
-size_row(png_byte buffer[SIZE_ROWMAX], png_uint_32 bit_width, png_uint_32 y)
-{
- /* height is in the range 1 to 16, so: */
- y = ((y & 1) << 7) + ((y & 2) << 6) + ((y & 4) << 5) + ((y & 8) << 4);
- /* the following ensures bits are set in small images: */
- y ^= 0xA5;
-
- while (bit_width >= 8)
- *buffer++ = (png_byte)y++, bit_width -= 8;
-
- /* There may be up to 7 remaining bits, these go in the most significant
- * bits of the byte.
- */
- if (bit_width > 0)
- {
- png_uint_32 mask = (1U<<(8-bit_width))-1;
- *buffer = (png_byte)((*buffer & mask) | (y & ~mask));
- }
-}
-
-static void
-make_size_image(png_store* PNG_CONST ps, png_byte PNG_CONST colour_type,
- png_byte PNG_CONST bit_depth, int PNG_CONST interlace_type,
- png_uint_32 PNG_CONST w, png_uint_32 PNG_CONST h,
- int PNG_CONST do_interlace)
-{
- context(ps, fault);
-
- Try
- {
- png_infop pi;
- png_structp pp;
- unsigned int pixel_size;
-
- /* Make a name and get an appropriate id for the store: */
- char name[FILE_NAME_SIZE];
- PNG_CONST png_uint_32 id = FILEID(colour_type, bit_depth, 0/*palette*/,
- interlace_type, w, h, do_interlace);
-
- standard_name_from_id(name, sizeof name, 0, id);
- pp = set_store_for_write(ps, &pi, name);
-
- /* In the event of a problem return control to the Catch statement below
- * to do the clean up - it is not possible to 'return' directly from a Try
- * block.
- */
- if (pp == NULL)
- Throw ps;
-
- png_set_IHDR(pp, pi, w, h, bit_depth, colour_type, interlace_type,
- PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
-
- if (colour_type == 3) /* palette */
- init_standard_palette(ps, pp, pi, 1U << bit_depth, 0/*do tRNS*/);
-
- png_write_info(pp, pi);
-
- /* Calculate the bit size, divide by 8 to get the byte size - this won't
- * overflow because we know the w values are all small enough even for
- * a system where 'unsigned int' is only 16 bits.
- */
- pixel_size = bit_size(pp, colour_type, bit_depth);
- if (png_get_rowbytes(pp, pi) != ((w * pixel_size) + 7) / 8)
- png_error(pp, "row size incorrect");
-
- else
- {
- int npasses = npasses_from_interlace_type(pp, interlace_type);
- png_uint_32 y;
- int pass;
- png_byte image[16][SIZE_ROWMAX];
-
- /* To help consistent error detection make the parts of this buffer
- * that aren't set below all '1':
- */
- memset(image, 0xff, sizeof image);
-
- if (!do_interlace && npasses != png_set_interlace_handling(pp))
- png_error(pp, "write: png_set_interlace_handling failed");
-
- /* Prepare the whole image first to avoid making it 7 times: */
- for (y=0; y<h; ++y)
- size_row(image[y], w * pixel_size, y);
-
- for (pass=0; pass<npasses; ++pass)
- {
- /* The following two are for checking the macros: */
- PNG_CONST png_uint_32 wPass = PNG_PASS_COLS(w, pass);
-
- /* If do_interlace is set we don't call png_write_row for every
- * row because some of them are empty. In fact, for a 1x1 image,
- * most of them are empty!
- */
- for (y=0; y<h; ++y)
- {
- png_const_bytep row = image[y];
- png_byte tempRow[SIZE_ROWMAX];
-
- /* If do_interlace *and* the image is interlaced we
- * need a reduced interlace row; this may be reduced
- * to empty.
- */
- if (do_interlace && interlace_type == PNG_INTERLACE_ADAM7)
- {
- /* The row must not be written if it doesn't exist, notice
- * that there are two conditions here, either the row isn't
- * ever in the pass or the row would be but isn't wide
- * enough to contribute any pixels. In fact the wPass test
- * can be used to skip the whole y loop in this case.
- */
- if (PNG_ROW_IN_INTERLACE_PASS(y, pass) && wPass > 0)
- {
- /* Set to all 1's for error detection (libpng tends to
- * set unset things to 0).
- */
- memset(tempRow, 0xff, sizeof tempRow);
- interlace_row(tempRow, row, pixel_size, w, pass);
- row = tempRow;
- }
- else
- continue;
- }
-
- /* Only get to here if the row has some pixels in it. */
- png_write_row(pp, row);
- }
- }
- }
-
- png_write_end(pp, pi);
-
- /* And store this under the appropriate id, then clean up. */
- store_storefile(ps, id);
-
- store_write_reset(ps);
- }
-
- Catch(fault)
- {
- /* Use the png_store returned by the exception. This may help the compiler
- * because 'ps' is not used in this branch of the setjmp. Note that fault
- * and ps will always be the same value.
- */
- store_write_reset(fault);
- }
-}
-
-static void
-make_size(png_store* PNG_CONST ps, png_byte PNG_CONST colour_type, int bdlo,
- int PNG_CONST bdhi)
-{
- for (; bdlo <= bdhi; ++bdlo)
- {
- png_uint_32 width;
-
- for (width = 1; width <= 16; ++width)
- {
- png_uint_32 height;
-
- for (height = 1; height <= 16; ++height)
- {
- /* The four combinations of DIY interlace and interlace or not -
- * no interlace + DIY should be identical to no interlace with
- * libpng doing it.
- */
- make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_NONE,
- width, height, 0);
- make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_NONE,
- width, height, 1);
- make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_ADAM7,
- width, height, 0);
- make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_ADAM7,
- width, height, 1);
- }
- }
- }
-}
-
-static void
-make_size_images(png_store *ps)
-{
- /* This is in case of errors. */
- safecat(ps->test, sizeof ps->test, 0, "make size images");
-
- /* Arguments are colour_type, low bit depth, high bit depth
- */
- make_size(ps, 0, 0, WRITE_BDHI);
- make_size(ps, 2, 3, WRITE_BDHI);
- make_size(ps, 3, 0, 3 /*palette: max 8 bits*/);
- make_size(ps, 4, 3, WRITE_BDHI);
- make_size(ps, 6, 3, WRITE_BDHI);
-}
-
-/* Return a row based on image id and 'y' for checking: */
-static void
-standard_row(png_structp pp, png_byte std[STANDARD_ROWMAX], png_uint_32 id,
- png_uint_32 y)
-{
- if (WIDTH_FROM_ID(id) == 0)
- transform_row(pp, std, COL_FROM_ID(id), DEPTH_FROM_ID(id), y);
- else
- size_row(std, WIDTH_FROM_ID(id) * bit_size(pp, COL_FROM_ID(id),
- DEPTH_FROM_ID(id)), y);
-}
-
-/* Tests - individual test cases */
-/* Like 'make_standard' but errors are deliberately introduced into the calls
- * to ensure that they get detected - it should not be possible to write an
- * invalid image with libpng!
- */
-#ifdef PNG_WARNINGS_SUPPORTED
-static void
-sBIT0_error_fn(png_structp pp, png_infop pi)
-{
- /* 0 is invalid... */
- png_color_8 bad;
- bad.red = bad.green = bad.blue = bad.gray = bad.alpha = 0;
- png_set_sBIT(pp, pi, &bad);
-}
-
-static void
-sBIT_error_fn(png_structp pp, png_infop pi)
-{
- png_byte bit_depth;
- png_color_8 bad;
-
- if (png_get_color_type(pp, pi) == PNG_COLOR_TYPE_PALETTE)
- bit_depth = 8;
-
- else
- bit_depth = png_get_bit_depth(pp, pi);
-
- /* Now we know the bit depth we can easily generate an invalid sBIT entry */
- bad.red = bad.green = bad.blue = bad.gray = bad.alpha =
- (png_byte)(bit_depth+1);
- png_set_sBIT(pp, pi, &bad);
-}
-
-static PNG_CONST struct
-{
- void (*fn)(png_structp, png_infop);
- PNG_CONST char *msg;
- unsigned int warning :1; /* the error is a warning... */
-} error_test[] =
- {
- /* no warnings makes these errors undetectable. */
- { sBIT0_error_fn, "sBIT(0): failed to detect error", 1 },
- { sBIT_error_fn, "sBIT(too big): failed to detect error", 1 },
- };
-
-static void
-make_error(png_store* volatile ps, png_byte PNG_CONST colour_type,
- png_byte bit_depth, int interlace_type, int test, png_const_charp name)
-{
- context(ps, fault);
-
- Try
- {
- png_structp pp;
- png_infop pi;
-
- pp = set_store_for_write(ps, &pi, name);
-
- if (pp == NULL)
- Throw ps;
-
- png_set_IHDR(pp, pi, transform_width(pp, colour_type, bit_depth),
- transform_height(pp, colour_type, bit_depth), bit_depth, colour_type,
- interlace_type, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
-
- if (colour_type == 3) /* palette */
- init_standard_palette(ps, pp, pi, 1U << bit_depth, 0/*do tRNS*/);
-
- /* Time for a few errors; these are in various optional chunks, the
- * standard tests test the standard chunks pretty well.
- */
-# define exception__prev exception_prev_1
-# define exception__env exception_env_1
- Try
- {
- /* Expect this to throw: */
- ps->expect_error = !error_test[test].warning;
- ps->expect_warning = error_test[test].warning;
- ps->saw_warning = 0;
- error_test[test].fn(pp, pi);
-
- /* Normally the error is only detected here: */
- png_write_info(pp, pi);
-
- /* And handle the case where it was only a warning: */
- if (ps->expect_warning && ps->saw_warning)
- Throw ps;
-
- /* If we get here there is a problem, we have success - no error or
- * no warning - when we shouldn't have success. Log an error.
- */
- store_log(ps, pp, error_test[test].msg, 1 /*error*/);
- }
-
- Catch (fault)
- ps = fault; /* expected exit, make sure ps is not clobbered */
-#undef exception__prev
-#undef exception__env
-
- /* And clear these flags */
- ps->expect_error = 0;
- ps->expect_warning = 0;
-
- /* Now write the whole image, just to make sure that the detected, or
- * undetected, errro has not created problems inside libpng.
- */
- if (png_get_rowbytes(pp, pi) !=
- transform_rowsize(pp, colour_type, bit_depth))
- png_error(pp, "row size incorrect");
-
- else
- {
- png_uint_32 h = transform_height(pp, colour_type, bit_depth);
- int npasses = png_set_interlace_handling(pp);
- int pass;
-
- if (npasses != npasses_from_interlace_type(pp, interlace_type))
- png_error(pp, "write: png_set_interlace_handling failed");
-
- for (pass=0; pass<npasses; ++pass)
- {
- png_uint_32 y;
-
- for (y=0; y<h; ++y)
- {
- png_byte buffer[TRANSFORM_ROWMAX];
-
- transform_row(pp, buffer, colour_type, bit_depth, y);
- png_write_row(pp, buffer);
- }
- }
- }
-
- png_write_end(pp, pi);
-
- /* The following deletes the file that was just written. */
- store_write_reset(ps);
- }
-
- Catch(fault)
- {
- store_write_reset(fault);
- }
-}
-
-static int
-make_errors(png_modifier* PNG_CONST pm, png_byte PNG_CONST colour_type,
- int bdlo, int PNG_CONST bdhi)
-{
- for (; bdlo <= bdhi; ++bdlo)
- {
- int interlace_type;
-
- for (interlace_type = PNG_INTERLACE_NONE;
- interlace_type < PNG_INTERLACE_LAST; ++interlace_type)
- {
- unsigned int test;
- char name[FILE_NAME_SIZE];
-
- standard_name(name, sizeof name, 0, colour_type, 1<<bdlo, 0,
- interlace_type, 0, 0, 0);
-
- for (test=0; test<(sizeof error_test)/(sizeof error_test[0]); ++test)
- {
- make_error(&pm->this, colour_type, DEPTH(bdlo), interlace_type,
- test, name);
-
- if (fail(pm))
- return 0;
- }
- }
- }
-
- return 1; /* keep going */
-}
-#endif
-
-static void
-perform_error_test(png_modifier *pm)
-{
-#ifdef PNG_WARNINGS_SUPPORTED /* else there are no cases that work! */
- /* Need to do this here because we just write in this test. */
- safecat(pm->this.test, sizeof pm->this.test, 0, "error test");
-
- if (!make_errors(pm, 0, 0, WRITE_BDHI))
- return;
-
- if (!make_errors(pm, 2, 3, WRITE_BDHI))
- return;
-
- if (!make_errors(pm, 3, 0, 3))
- return;
-
- if (!make_errors(pm, 4, 3, WRITE_BDHI))
- return;
-
- if (!make_errors(pm, 6, 3, WRITE_BDHI))
- return;
-#else
- UNUSED(pm)
-#endif
-}
-
-/* This is just to validate the internal PNG formatting code - if this fails
- * then the warning messages the library outputs will probably be garbage.
- */
-static void
-perform_formatting_test(png_store *volatile ps)
-{
-#ifdef PNG_TIME_RFC1123_SUPPORTED
- /* The handle into the formatting code is the RFC1123 support; this test does
- * nothing if that is compiled out.
- */
- context(ps, fault);
-
- Try
- {
- png_const_charp correct = "29 Aug 2079 13:53:60 +0000";
- png_const_charp result;
- png_structp pp;
- png_time pt;
-
- pp = set_store_for_write(ps, NULL, "libpng formatting test");
-
- if (pp == NULL)
- Throw ps;
-
-
- /* Arbitrary settings: */
- pt.year = 2079;
- pt.month = 8;
- pt.day = 29;
- pt.hour = 13;
- pt.minute = 53;
- pt.second = 60; /* a leap second */
-
- result = png_convert_to_rfc1123(pp, &pt);
-
- if (result == NULL)
- png_error(pp, "png_convert_to_rfc1123 failed");
-
- if (strcmp(result, correct) != 0)
- {
- size_t pos = 0;
- char msg[128];
-
- pos = safecat(msg, sizeof msg, pos, "png_convert_to_rfc1123(");
- pos = safecat(msg, sizeof msg, pos, correct);
- pos = safecat(msg, sizeof msg, pos, ") returned: '");
- pos = safecat(msg, sizeof msg, pos, result);
- pos = safecat(msg, sizeof msg, pos, "'");
-
- png_error(pp, msg);
- }
-
- store_write_reset(ps);
- }
-
- Catch(fault)
- {
- store_write_reset(fault);
- }
-#else
- UNUSED(ps)
-#endif
-}
-
-/* Because we want to use the same code in both the progressive reader and the
- * sequential reader it is necessary to deal with the fact that the progressive
- * reader callbacks only have one parameter (png_get_progressive_ptr()), so this
- * must contain all the test parameters and all the local variables directly
- * accessible to the sequential reader implementation.
- *
- * The technique adopted is to reinvent part of what Dijkstra termed a
- * 'display'; an array of pointers to the stack frames of enclosing functions so
- * that a nested function definition can access the local (C auto) variables of
- * the functions that contain its definition. In fact C provides the first
- * pointer (the local variables - the stack frame pointer) and the last (the
- * global variables - the BCPL global vector typically implemented as global
- * addresses), this code requires one more pointer to make the display - the
- * local variables (and function call parameters) of the function that actually
- * invokes either the progressive or sequential reader.
- *
- * Perhaps confusingly this technique is confounded with classes - the
- * 'standard_display' defined here is sub-classed as the 'gamma_display' below.
- * A gamma_display is a standard_display, taking advantage of the ANSI-C
- * requirement that the pointer to the first member of a structure must be the
- * same as the pointer to the structure. This allows us to reuse standard_
- * functions in the gamma test code; something that could not be done with
- * nested functions!
- */
-typedef struct standard_display
-{
- png_store* ps; /* Test parameters (passed to the function) */
- png_byte colour_type;
- png_byte bit_depth;
- png_byte red_sBIT; /* Input data sBIT values. */
- png_byte green_sBIT;
- png_byte blue_sBIT;
- png_byte alpha_sBIT;
- int interlace_type;
- png_uint_32 id; /* Calculated file ID */
- png_uint_32 w; /* Width of image */
- png_uint_32 h; /* Height of image */
- int npasses; /* Number of interlaced passes */
- png_uint_32 pixel_size; /* Width of one pixel in bits */
- png_uint_32 bit_width; /* Width of output row in bits */
- size_t cbRow; /* Bytes in a row of the output image */
- int do_interlace; /* Do interlacing internally */
- int is_transparent; /* Transparency information was present. */
- int speed; /* Doing a speed test */
- int use_update_info;/* Call update_info, not start_image */
- struct
- {
- png_uint_16 red;
- png_uint_16 green;
- png_uint_16 blue;
- } transparent; /* The transparent color, if set. */
- int npalette; /* Number of entries in the palette. */
- store_palette
- palette;
-} standard_display;
-
-static void
-standard_display_init(standard_display *dp, png_store* ps, png_uint_32 id,
- int do_interlace, int use_update_info)
-{
- memset(dp, 0, sizeof *dp);
-
- dp->ps = ps;
- dp->colour_type = COL_FROM_ID(id);
- dp->bit_depth = DEPTH_FROM_ID(id);
- if (dp->colour_type == 3)
- dp->red_sBIT = dp->blue_sBIT = dp->green_sBIT = dp->alpha_sBIT = 8;
- else
- dp->red_sBIT = dp->blue_sBIT = dp->green_sBIT = dp->alpha_sBIT =
- dp->bit_depth;
- dp->interlace_type = INTERLACE_FROM_ID(id);
- dp->id = id;
- /* All the rest are filled in after the read_info: */
- dp->w = 0;
- dp->h = 0;
- dp->npasses = 0;
- dp->pixel_size = 0;
- dp->bit_width = 0;
- dp->cbRow = 0;
- dp->do_interlace = do_interlace;
- dp->is_transparent = 0;
- dp->speed = ps->speed;
- dp->use_update_info = use_update_info;
- dp->npalette = 0;
- /* Preset the transparent color to black: */
- memset(&dp->transparent, 0, sizeof dp->transparent);
- /* Preset the palette to full intensity/opaque througout: */
- memset(dp->palette, 0xff, sizeof dp->palette);
-}
-
-/* Initialize the palette fields - this must be done later because the palette
- * comes from the particular png_store_file that is selected.
- */
-static void
-standard_palette_init(standard_display *dp)
-{
- store_palette_entry *palette = store_current_palette(dp->ps, &dp->npalette);
-
- /* The remaining entries remain white/opaque. */
- if (dp->npalette > 0)
- {
- int i = dp->npalette;
- memcpy(dp->palette, palette, i * sizeof *palette);
-
- /* Check for a non-opaque palette entry: */
- while (--i >= 0)
- if (palette[i].alpha < 255)
- break;
-
-# ifdef __GNUC__
- /* GCC can't handle the more obviously optimizable version. */
- if (i >= 0)
- dp->is_transparent = 1;
- else
- dp->is_transparent = 0;
-# else
- dp->is_transparent = (i >= 0);
-# endif
- }
-}
-
-/* Utility to read the palette from the PNG file and convert it into
- * store_palette format. This returns 1 if there is any transparency in the
- * palette (it does not check for a transparent colour in the non-palette case.)
- */
-static int
-read_palette(store_palette palette, int *npalette, png_structp pp, png_infop pi)
-{
- png_colorp pal;
- png_bytep trans_alpha;
- int num;
-
- pal = 0;
- *npalette = -1;
-
- if (png_get_PLTE(pp, pi, &pal, npalette) & PNG_INFO_PLTE)
- {
- int i = *npalette;
-
- if (i <= 0 || i > 256)
- png_error(pp, "validate: invalid PLTE count");
-
- while (--i >= 0)
- {
- palette[i].red = pal[i].red;
- palette[i].green = pal[i].green;
- palette[i].blue = pal[i].blue;
- }
-
- /* Mark the remainder of the entries with a flag value (other than
- * white/opaque which is the flag value stored above.)
- */
- memset(palette + *npalette, 126, (256-*npalette) * sizeof *palette);
- }
-
- else /* !png_get_PLTE */
- {
- if (*npalette != (-1))
- png_error(pp, "validate: invalid PLTE result");
- /* But there is no palette, so record this: */
- *npalette = 0;
- memset(palette, 113, sizeof palette);
- }
-
- trans_alpha = 0;
- num = 2; /* force error below */
- if ((png_get_tRNS(pp, pi, &trans_alpha, &num, 0) & PNG_INFO_tRNS) != 0 &&
- (trans_alpha != NULL || num != 1/*returns 1 for a transparent color*/) &&
- /* Oops, if a palette tRNS gets expanded png_read_update_info (at least so
- * far as 1.5.4) does not remove the trans_alpha pointer, only num_trans,
- * so in the above call we get a success, we get a pointer (who knows what
- * to) and we get num_trans == 0:
- */
- !(trans_alpha != NULL && num == 0)) /* TODO: fix this in libpng. */
- {
- int i;
-
- /* Any of these are crash-worthy - given the implementation of
- * png_get_tRNS up to 1.5 an app won't crash if it just checks the
- * result above and fails to check that the variables it passed have
- * actually been filled in! Note that if the app were to pass the
- * last, png_color_16p, variable too it couldn't rely on this.
- */
- if (trans_alpha == NULL || num <= 0 || num > 256 || num > *npalette)
- png_error(pp, "validate: unexpected png_get_tRNS (palette) result");
-
- for (i=0; i<num; ++i)
- palette[i].alpha = trans_alpha[i];
-
- for (num=*npalette; i<num; ++i)
- palette[i].alpha = 255;
-
- for (; i<256; ++i)
- palette[i].alpha = 33; /* flag value */
-
- return 1; /* transparency */
- }
-
- else
- {
- /* No palette transparency - just set the alpha channel to opaque. */
- int i;
-
- for (i=0, num=*npalette; i<num; ++i)
- palette[i].alpha = 255;
-
- for (; i<256; ++i)
- palette[i].alpha = 55; /* flag value */
-
- return 0; /* no transparency */
- }
-}
-
-/* Utility to validate the palette if it should not have changed (the
- * non-transform case).
- */
-static void
-standard_palette_validate(standard_display *dp, png_structp pp, png_infop pi)
-{
- int npalette;
- store_palette palette;
-
- if (read_palette(palette, &npalette, pp, pi) != dp->is_transparent)
- png_error(pp, "validate: palette transparency changed");
-
- if (npalette != dp->npalette)
- {
- size_t pos = 0;
- char msg[64];
-
- pos = safecat(msg, sizeof msg, pos, "validate: palette size changed: ");
- pos = safecatn(msg, sizeof msg, pos, dp->npalette);
- pos = safecat(msg, sizeof msg, pos, " -> ");
- pos = safecatn(msg, sizeof msg, pos, npalette);
- png_error(pp, msg);
- }
-
- {
- int i = npalette; /* npalette is aliased */
-
- while (--i >= 0)
- if (palette[i].red != dp->palette[i].red ||
- palette[i].green != dp->palette[i].green ||
- palette[i].blue != dp->palette[i].blue ||
- palette[i].alpha != dp->palette[i].alpha)
- png_error(pp, "validate: PLTE or tRNS chunk changed");
- }
-}
-
-/* By passing a 'standard_display' the progressive callbacks can be used
- * directly by the sequential code, the functions suffixed "_imp" are the
- * implementations, the functions without the suffix are the callbacks.
- *
- * The code for the info callback is split into two because this callback calls
- * png_read_update_info or png_start_read_image and what gets called depends on
- * whether the info needs updating (we want to test both calls in pngvalid.)
- */
-static void
-standard_info_part1(standard_display *dp, png_structp pp, png_infop pi)
-{
- if (png_get_bit_depth(pp, pi) != dp->bit_depth)
- png_error(pp, "validate: bit depth changed");
-
- if (png_get_color_type(pp, pi) != dp->colour_type)
- png_error(pp, "validate: color type changed");
-
- if (png_get_filter_type(pp, pi) != PNG_FILTER_TYPE_BASE)
- png_error(pp, "validate: filter type changed");
-
- if (png_get_interlace_type(pp, pi) != dp->interlace_type)
- png_error(pp, "validate: interlacing changed");
-
- if (png_get_compression_type(pp, pi) != PNG_COMPRESSION_TYPE_BASE)
- png_error(pp, "validate: compression type changed");
-
- dp->w = png_get_image_width(pp, pi);
-
- if (dp->w != standard_width(pp, dp->id))
- png_error(pp, "validate: image width changed");
-
- dp->h = png_get_image_height(pp, pi);
-
- if (dp->h != standard_height(pp, dp->id))
- png_error(pp, "validate: image height changed");
-
- /* Record (but don't check at present) the input sBIT according to the colour
- * type information.
- */
- {
- png_color_8p sBIT = 0;
-
- if (png_get_sBIT(pp, pi, &sBIT) & PNG_INFO_sBIT)
- {
- int sBIT_invalid = 0;
-
- if (sBIT == 0)
- png_error(pp, "validate: unexpected png_get_sBIT result");
-
- if (dp->colour_type & PNG_COLOR_MASK_COLOR)
- {
- if (sBIT->red == 0 || sBIT->red > dp->bit_depth)
- sBIT_invalid = 1;
- else
- dp->red_sBIT = sBIT->red;
-
- if (sBIT->green == 0 || sBIT->green > dp->bit_depth)
- sBIT_invalid = 1;
- else
- dp->green_sBIT = sBIT->green;
-
- if (sBIT->blue == 0 || sBIT->blue > dp->bit_depth)
- sBIT_invalid = 1;
- else
- dp->blue_sBIT = sBIT->blue;
- }
-
- else /* !COLOR */
- {
- if (sBIT->gray == 0 || sBIT->gray > dp->bit_depth)
- sBIT_invalid = 1;
- else
- dp->blue_sBIT = dp->green_sBIT = dp->red_sBIT = sBIT->gray;
- }
-
- /* All 8 bits in tRNS for a palette image are significant - see the
- * spec.
- */
- if (dp->colour_type & PNG_COLOR_MASK_ALPHA)
- {
- if (sBIT->alpha == 0 || sBIT->alpha > dp->bit_depth)
- sBIT_invalid = 1;
- else
- dp->alpha_sBIT = sBIT->alpha;
- }
-
- if (sBIT_invalid)
- png_error(pp, "validate: sBIT value out of range");
- }
- }
-
- /* Important: this is validating the value *before* any transforms have been
- * put in place. It doesn't matter for the standard tests, where there are
- * no transforms, but it does for other tests where rowbytes may change after
- * png_read_update_info.
- */
- if (png_get_rowbytes(pp, pi) != standard_rowsize(pp, dp->id))
- png_error(pp, "validate: row size changed");
-
- /* Validate the colour type 3 palette (this can be present on other color
- * types.)
- */
- standard_palette_validate(dp, pp, pi);
-
- /* In any case always check for a tranparent color (notice that the
- * colour type 3 case must not give a successful return on the get_tRNS call
- * with these arguments!)
- */
- {
- png_color_16p trans_color = 0;
-
- if (png_get_tRNS(pp, pi, 0, 0, &trans_color) & PNG_INFO_tRNS)
- {
- if (trans_color == 0)
- png_error(pp, "validate: unexpected png_get_tRNS (color) result");
-
- switch (dp->colour_type)
- {
- case 0:
- dp->transparent.red = dp->transparent.green = dp->transparent.blue =
- trans_color->gray;
- dp->is_transparent = 1;
- break;
-
- case 2:
- dp->transparent.red = trans_color->red;
- dp->transparent.green = trans_color->green;
- dp->transparent.blue = trans_color->blue;
- dp->is_transparent = 1;
- break;
-
- case 3:
- /* Not expected because it should result in the array case
- * above.
- */
- png_error(pp, "validate: unexpected png_get_tRNS result");
- break;
-
- default:
- png_error(pp, "validate: invalid tRNS chunk with alpha image");
- }
- }
- }
-
- /* Read the number of passes - expected to match the value used when
- * creating the image (interlaced or not). This has the side effect of
- * turning on interlace handling (if do_interlace is not set.)
- */
- dp->npasses = npasses_from_interlace_type(pp, dp->interlace_type);
- if (!dp->do_interlace && dp->npasses != png_set_interlace_handling(pp))
- png_error(pp, "validate: file changed interlace type");
-
- /* Caller calls png_read_update_info or png_start_read_image now, then calls
- * part2.
- */
-}
-
-/* This must be called *after* the png_read_update_info call to get the correct
- * 'rowbytes' value, otherwise png_get_rowbytes will refer to the untransformed
- * image.
- */
-static void
-standard_info_part2(standard_display *dp, png_structp pp, png_infop pi,
- int nImages)
-{
- /* Record cbRow now that it can be found. */
- dp->pixel_size = bit_size(pp, png_get_color_type(pp, pi),
- png_get_bit_depth(pp, pi));
- dp->bit_width = png_get_image_width(pp, pi) * dp->pixel_size;
- dp->cbRow = png_get_rowbytes(pp, pi);
-
- /* Validate the rowbytes here again. */
- if (dp->cbRow != (dp->bit_width+7)/8)
- png_error(pp, "bad png_get_rowbytes calculation");
-
- /* Then ensure there is enough space for the output image(s). */
- store_ensure_image(dp->ps, pp, nImages, dp->cbRow, dp->h);
-}
-
-static void
-standard_info_imp(standard_display *dp, png_structp pp, png_infop pi,
- int nImages)
-{
- /* Note that the validation routine has the side effect of turning on
- * interlace handling in the subsequent code.
- */
- standard_info_part1(dp, pp, pi);
-
- /* And the info callback has to call this (or png_read_update_info - see
- * below in the png_modifier code for that variant.
- */
- if (dp->use_update_info)
- {
- /* For debugging the effect of multiple calls: */
- int i = dp->use_update_info;
- while (i-- > 0)
- png_read_update_info(pp, pi);
- }
-
- else
- png_start_read_image(pp);
-
- /* Validate the height, width and rowbytes plus ensure that sufficient buffer
- * exists for decoding the image.
- */
- standard_info_part2(dp, pp, pi, nImages);
-}
-
-static void
-standard_info(png_structp pp, png_infop pi)
-{
- standard_display *dp = voidcast(standard_display*,
- png_get_progressive_ptr(pp));
-
- /* Call with nImages==1 because the progressive reader can only produce one
- * image.
- */
- standard_info_imp(dp, pp, pi, 1 /*only one image*/);
-}
-
-static void
-progressive_row(png_structp pp, png_bytep new_row, png_uint_32 y, int pass)
-{
- PNG_CONST standard_display *dp = voidcast(standard_display*,
- png_get_progressive_ptr(pp));
-
- /* When handling interlacing some rows will be absent in each pass, the
- * callback still gets called, but with a NULL pointer. This is checked
- * in the 'else' clause below. We need our own 'cbRow', but we can't call
- * png_get_rowbytes because we got no info structure.
- */
- if (new_row != NULL)
- {
- png_bytep row;
-
- /* In the case where the reader doesn't do the interlace it gives
- * us the y in the sub-image:
- */
- if (dp->do_interlace && dp->interlace_type == PNG_INTERLACE_ADAM7)
- {
-#ifdef PNG_USER_TRANSFORM_INFO_SUPPORTED
- /* Use this opportunity to validate the png 'current' APIs: */
- if (y != png_get_current_row_number(pp))
- png_error(pp, "png_get_current_row_number is broken");
-
- if (pass != png_get_current_pass_number(pp))
- png_error(pp, "png_get_current_pass_number is broken");
-#endif
-
- y = PNG_ROW_FROM_PASS_ROW(y, pass);
- }
-
- /* Validate this just in case. */
- if (y >= dp->h)
- png_error(pp, "invalid y to progressive row callback");
-
- row = store_image_row(dp->ps, pp, 0, y);
-
-#ifdef PNG_READ_INTERLACING_SUPPORTED
- /* Combine the new row into the old: */
- if (dp->do_interlace)
- {
- if (dp->interlace_type == PNG_INTERLACE_ADAM7)
- deinterlace_row(row, new_row, dp->pixel_size, dp->w, pass);
- else
- row_copy(row, new_row, dp->pixel_size * dp->w);
- }
- else
- png_progressive_combine_row(pp, row, new_row);
- } else if (dp->interlace_type == PNG_INTERLACE_ADAM7 &&
- PNG_ROW_IN_INTERLACE_PASS(y, pass) &&
- PNG_PASS_COLS(dp->w, pass) > 0)
- png_error(pp, "missing row in progressive de-interlacing");
-#endif /* PNG_READ_INTERLACING_SUPPORTED */
-}
-
-static void
-sequential_row(standard_display *dp, png_structp pp, png_infop pi,
- PNG_CONST int iImage, PNG_CONST int iDisplay)
-{
- PNG_CONST int npasses = dp->npasses;
- PNG_CONST int do_interlace = dp->do_interlace &&
- dp->interlace_type == PNG_INTERLACE_ADAM7;
- PNG_CONST png_uint_32 height = standard_height(pp, dp->id);
- PNG_CONST png_uint_32 width = standard_width(pp, dp->id);
- PNG_CONST png_store* ps = dp->ps;
- int pass;
-
- for (pass=0; pass<npasses; ++pass)
- {
- png_uint_32 y;
- png_uint_32 wPass = PNG_PASS_COLS(width, pass);
-
- for (y=0; y<height; ++y)
- {
- if (do_interlace)
- {
- /* wPass may be zero or this row may not be in this pass.
- * png_read_row must not be called in either case.
- */
- if (wPass > 0 && PNG_ROW_IN_INTERLACE_PASS(y, pass))
- {
- /* Read the row into a pair of temporary buffers, then do the
- * merge here into the output rows.
- */
- png_byte row[STANDARD_ROWMAX], display[STANDARD_ROWMAX];
-
- /* The following aids (to some extent) error detection - we can
- * see where png_read_row wrote. Use opposite values in row and
- * display to make this easier. Don't use 0xff (which is used in
- * the image write code to fill unused bits) or 0 (which is a
- * likely value to overwrite unused bits with).
- */
- memset(row, 0xc5, sizeof row);
- memset(display, 0x5c, sizeof display);
-
- png_read_row(pp, row, display);
-
- if (iImage >= 0)
- deinterlace_row(store_image_row(ps, pp, iImage, y), row,
- dp->pixel_size, dp->w, pass);
-
- if (iDisplay >= 0)
- deinterlace_row(store_image_row(ps, pp, iDisplay, y), display,
- dp->pixel_size, dp->w, pass);
- }
- }
- else
- png_read_row(pp,
- iImage >= 0 ? store_image_row(ps, pp, iImage, y) : NULL,
- iDisplay >= 0 ? store_image_row(ps, pp, iDisplay, y) : NULL);
- }
- }
-
- /* And finish the read operation (only really necessary if the caller wants
- * to find additional data in png_info from chunks after the last IDAT.)
- */
- png_read_end(pp, pi);
-}
-
-static void
-standard_row_validate(standard_display *dp, png_structp pp,
- int iImage, int iDisplay, png_uint_32 y)
-{
- int where;
- png_byte std[STANDARD_ROWMAX];
-
- /* The row must be pre-initialized to the magic number here for the size
- * tests to pass:
- */
- memset(std, 178, sizeof std);
- standard_row(pp, std, dp->id, y);
-
- /* At the end both the 'row' and 'display' arrays should end up identical.
- * In earlier passes 'row' will be partially filled in, with only the pixels
- * that have been read so far, but 'display' will have those pixels
- * replicated to fill the unread pixels while reading an interlaced image.
-#if PNG_LIBPNG_VER < 10506
- * The side effect inside the libpng sequential reader is that the 'row'
- * array retains the correct values for unwritten pixels within the row
- * bytes, while the 'display' array gets bits off the end of the image (in
- * the last byte) trashed. Unfortunately in the progressive reader the
- * row bytes are always trashed, so we always do a pixel_cmp here even though
- * a memcmp of all cbRow bytes will succeed for the sequential reader.
-#endif
- */
- if (iImage >= 0 &&
- (where = pixel_cmp(std, store_image_row(dp->ps, pp, iImage, y),
- dp->bit_width)) != 0)
- {
- char msg[64];
- sprintf(msg, "PNG image row[%d][%d] changed from %.2x to %.2x", y,
- where-1, std[where-1],
- store_image_row(dp->ps, pp, iImage, y)[where-1]);
- png_error(pp, msg);
- }
-
-#if PNG_LIBPNG_VER < 10506
- /* In this case use pixel_cmp because we need to compare a partial
- * byte at the end of the row if the row is not an exact multiple
- * of 8 bits wide. (This is fixed in libpng-1.5.6 and pixel_cmp is
- * changed to match!)
- */
-#endif
- if (iDisplay >= 0 &&
- (where = pixel_cmp(std, store_image_row(dp->ps, pp, iDisplay, y),
- dp->bit_width)) != 0)
- {
- char msg[64];
- sprintf(msg, "display row[%d][%d] changed from %.2x to %.2x", y,
- where-1, std[where-1],
- store_image_row(dp->ps, pp, iDisplay, y)[where-1]);
- png_error(pp, msg);
- }
-}
-
-static void
-standard_image_validate(standard_display *dp, png_structp pp, int iImage,
- int iDisplay)
-{
- png_uint_32 y;
-
- if (iImage >= 0)
- store_image_check(dp->ps, pp, iImage);
-
- if (iDisplay >= 0)
- store_image_check(dp->ps, pp, iDisplay);
-
- for (y=0; y<dp->h; ++y)
- standard_row_validate(dp, pp, iImage, iDisplay, y);
-
- /* This avoids false positives if the validation code is never called! */
- dp->ps->validated = 1;
-}
-
-static void
-standard_end(png_structp pp, png_infop pi)
-{
- standard_display *dp = voidcast(standard_display*,
- png_get_progressive_ptr(pp));
-
- UNUSED(pi)
-
- /* Validate the image - progressive reading only produces one variant for
- * interlaced images.
- */
- standard_image_validate(dp, pp, 0, -1);
-}
-
-/* A single test run checking the standard image to ensure it is not damaged. */
-static void
-standard_test(png_store* PNG_CONST psIn, png_uint_32 PNG_CONST id,
- int do_interlace, int use_update_info)
-{
- standard_display d;
- context(psIn, fault);
-
- /* Set up the display (stack frame) variables from the arguments to the
- * function and initialize the locals that are filled in later.
- */
- standard_display_init(&d, psIn, id, do_interlace, use_update_info);
-
- /* Everything is protected by a Try/Catch. The functions called also
- * typically have local Try/Catch blocks.
- */
- Try
- {
- png_structp pp;
- png_infop pi;
-
- /* Get a png_struct for reading the image. This will throw an error if it
- * fails, so we don't need to check the result.
- */
- pp = set_store_for_read(d.ps, &pi, d.id,
- d.do_interlace ? (d.ps->progressive ?
- "pngvalid progressive deinterlacer" :
- "pngvalid sequential deinterlacer") : (d.ps->progressive ?
- "progressive reader" : "sequential reader"));
-
- /* Initialize the palette correctly from the png_store_file. */
- standard_palette_init(&d);
-
- /* Introduce the correct read function. */
- if (d.ps->progressive)
- {
- png_set_progressive_read_fn(pp, &d, standard_info, progressive_row,
- standard_end);
-
- /* Now feed data into the reader until we reach the end: */
- store_progressive_read(d.ps, pp, pi);
- }
- else
- {
- /* Note that this takes the store, not the display. */
- png_set_read_fn(pp, d.ps, store_read);
-
- /* Check the header values: */
- png_read_info(pp, pi);
-
- /* The code tests both versions of the images that the sequential
- * reader can produce.
- */
- standard_info_imp(&d, pp, pi, 2 /*images*/);
-
- /* Need the total bytes in the image below; we can't get to this point
- * unless the PNG file values have been checked against the expected
- * values.
- */
- {
- sequential_row(&d, pp, pi, 0, 1);
-
- /* After the last pass loop over the rows again to check that the
- * image is correct.
- */
- if (!d.speed)
- standard_image_validate(&d, pp, 0, 1);
- else
- d.ps->validated = 1;
- }
- }
-
- /* Check for validation. */
- if (!d.ps->validated)
- png_error(pp, "image read failed silently");
-
- /* Successful completion. */
- }
-
- Catch(fault)
- d.ps = fault; /* make sure this hasn't been clobbered. */
-
- /* In either case clean up the store. */
- store_read_reset(d.ps);
-}
-
-static int
-test_standard(png_modifier* PNG_CONST pm, png_byte PNG_CONST colour_type,
- int bdlo, int PNG_CONST bdhi)
-{
- for (; bdlo <= bdhi; ++bdlo)
- {
- int interlace_type;
-
- for (interlace_type = PNG_INTERLACE_NONE;
- interlace_type < PNG_INTERLACE_LAST; ++interlace_type)
- {
- standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
- interlace_type, 0, 0, 0), 0/*do_interlace*/, pm->use_update_info);
-
- if (fail(pm))
- return 0;
- }
- }
-
- return 1; /* keep going */
-}
-
-static void
-perform_standard_test(png_modifier *pm)
-{
- /* Test each colour type over the valid range of bit depths (expressed as
- * log2(bit_depth) in turn, stop as soon as any error is detected.
- */
- if (!test_standard(pm, 0, 0, READ_BDHI))
- return;
-
- if (!test_standard(pm, 2, 3, READ_BDHI))
- return;
-
- if (!test_standard(pm, 3, 0, 3))
- return;
-
- if (!test_standard(pm, 4, 3, READ_BDHI))
- return;
-
- if (!test_standard(pm, 6, 3, READ_BDHI))
- return;
-}
-
-
-/********************************** SIZE TESTS ********************************/
-static int
-test_size(png_modifier* PNG_CONST pm, png_byte PNG_CONST colour_type,
- int bdlo, int PNG_CONST bdhi)
-{
- /* Run the tests on each combination.
- *
- * NOTE: on my 32 bit x86 each of the following blocks takes
- * a total of 3.5 seconds if done across every combo of bit depth
- * width and height. This is a waste of time in practice, hence the
- * hinc and winc stuff:
- */
- static PNG_CONST png_byte hinc[] = {1, 3, 11, 1, 5};
- static PNG_CONST png_byte winc[] = {1, 9, 5, 7, 1};
- for (; bdlo <= bdhi; ++bdlo)
- {
- png_uint_32 h, w;
-
- for (h=1; h<=16; h+=hinc[bdlo]) for (w=1; w<=16; w+=winc[bdlo])
- {
- /* First test all the 'size' images against the sequential
- * reader using libpng to deinterlace (where required.) This
- * validates the write side of libpng. There are four possibilities
- * to validate.
- */
- standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
- PNG_INTERLACE_NONE, w, h, 0), 0/*do_interlace*/,
- pm->use_update_info);
-
- if (fail(pm))
- return 0;
-
- standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
- PNG_INTERLACE_NONE, w, h, 1), 0/*do_interlace*/,
- pm->use_update_info);
-
- if (fail(pm))
- return 0;
-
- standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
- PNG_INTERLACE_ADAM7, w, h, 0), 0/*do_interlace*/,
- pm->use_update_info);
-
- if (fail(pm))
- return 0;
-
- standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
- PNG_INTERLACE_ADAM7, w, h, 1), 0/*do_interlace*/,
- pm->use_update_info);
-
- if (fail(pm))
- return 0;
-
- /* Now validate the interlaced read side - do_interlace true,
- * in the progressive case this does actually make a difference
- * to the code used in the non-interlaced case too.
- */
- standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
- PNG_INTERLACE_NONE, w, h, 0), 1/*do_interlace*/,
- pm->use_update_info);
-
- if (fail(pm))
- return 0;
-
- standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/,
- PNG_INTERLACE_ADAM7, w, h, 0), 1/*do_interlace*/,
- pm->use_update_info);
-
- if (fail(pm))
- return 0;
- }
- }
-
- return 1; /* keep going */
-}
-
-static void
-perform_size_test(png_modifier *pm)
-{
- /* Test each colour type over the valid range of bit depths (expressed as
- * log2(bit_depth) in turn, stop as soon as any error is detected.
- */
- if (!test_size(pm, 0, 0, READ_BDHI))
- return;
-
- if (!test_size(pm, 2, 3, READ_BDHI))
- return;
-
- /* For the moment don't do the palette test - it's a waste of time when
- * compared to the grayscale test.
- */
-#if 0
- if (!test_size(pm, 3, 0, 3))
- return;
-#endif
-
- if (!test_size(pm, 4, 3, READ_BDHI))
- return;
-
- if (!test_size(pm, 6, 3, READ_BDHI))
- return;
-}
-
-
-/******************************* TRANSFORM TESTS ******************************/
-#ifdef PNG_READ_TRANSFORMS_SUPPORTED
-/* A set of tests to validate libpng image transforms. The possibilities here
- * are legion because the transforms can be combined in a combinatorial
- * fashion. To deal with this some measure of restraint is required, otherwise
- * the tests would take forever.
- */
-typedef struct image_pixel
-{
- /* A local (pngvalid) representation of a PNG pixel, in all its
- * various forms.
- */
- unsigned int red, green, blue, alpha; /* For non-palette images. */
- unsigned int palette_index; /* For a palette image. */
- png_byte colour_type; /* As in the spec. */
- png_byte bit_depth; /* Defines bit size in row */
- png_byte sample_depth; /* Scale of samples */
- int have_tRNS; /* tRNS chunk may need processing */
-
- /* For checking the code calculates double precision floating point values
- * along with an error value, accumulated from the transforms. Because an
- * sBIT setting allows larger error bounds (indeed, by the spec, apparently
- * up to just less than +/-1 in the scaled value) the *lowest* sBIT for each
- * channel is stored. This sBIT value is folded in to the stored error value
- * at the end of the application of the transforms to the pixel.
- */
- double redf, greenf, bluef, alphaf;
- double rede, greene, bluee, alphae;
- png_byte red_sBIT, green_sBIT, blue_sBIT, alpha_sBIT;
-} image_pixel;
-
-/* Shared utility function, see below. */
-static void
-image_pixel_setf(image_pixel *this, unsigned int max)
-{
- this->redf = this->red / (double)max;
- this->greenf = this->green / (double)max;
- this->bluef = this->blue / (double)max;
- this->alphaf = this->alpha / (double)max;
-
- if (this->red < max)
- this->rede = this->redf * DBL_EPSILON;
- else
- this->rede = 0;
- if (this->green < max)
- this->greene = this->greenf * DBL_EPSILON;
- else
- this->greene = 0;
- if (this->blue < max)
- this->bluee = this->bluef * DBL_EPSILON;
- else
- this->bluee = 0;
- if (this->alpha < max)
- this->alphae = this->alphaf * DBL_EPSILON;
- else
- this->alphae = 0;
-}
-
-/* Initialize the structure for the next pixel - call this before doing any
- * transforms and call it for each pixel since all the fields may need to be
- * reset.
- */
-static void
-image_pixel_init(image_pixel *this, png_const_bytep row, png_byte colour_type,
- png_byte bit_depth, png_uint_32 x, store_palette palette)
-{
- PNG_CONST png_byte sample_depth = (png_byte)(colour_type ==
- PNG_COLOR_TYPE_PALETTE ? 8 : bit_depth);
- PNG_CONST unsigned int max = (1U<<sample_depth)-1;
-
- /* Initially just set everything to the same number and the alpha to opaque.
- * Note that this currently assumes a simple palette where entry x has colour
- * rgb(x,x,x)!
- */
- this->palette_index = this->red = this->green = this->blue =
- sample(row, colour_type, bit_depth, x, 0);
- this->alpha = max;
- this->red_sBIT = this->green_sBIT = this->blue_sBIT = this->alpha_sBIT =
- sample_depth;
-
- /* Then override as appropriate: */
- if (colour_type == 3) /* palette */
- {
- /* This permits the caller to default to the sample value. */
- if (palette != 0)
- {
- PNG_CONST unsigned int i = this->palette_index;
-
- this->red = palette[i].red;
- this->green = palette[i].green;
- this->blue = palette[i].blue;
- this->alpha = palette[i].alpha;
- }
- }
-
- else /* not palette */
- {
- unsigned int i = 0;
-
- if (colour_type & 2)
- {
- this->green = sample(row, colour_type, bit_depth, x, 1);
- this->blue = sample(row, colour_type, bit_depth, x, 2);
- i = 2;
- }
- if (colour_type & 4)
- this->alpha = sample(row, colour_type, bit_depth, x, ++i);
- }
-
- /* Calculate the scaled values, these are simply the values divided by
- * 'max' and the error is initialized to the double precision epsilon value
- * from the header file.
- */
- image_pixel_setf(this, max);
-
- /* Store the input information for use in the transforms - these will
- * modify the information.
- */
- this->colour_type = colour_type;
- this->bit_depth = bit_depth;
- this->sample_depth = sample_depth;
- this->have_tRNS = 0;
-}
-
-/* Convert a palette image to an rgb image. This necessarily converts the tRNS
- * chunk at the same time, because the tRNS will be in palette form. The way
- * palette validation works means that the original palette is never updated,
- * instead the image_pixel value from the row contains the RGB of the
- * corresponding palette entry and *this* is updated. Consequently this routine
- * only needs to change the colour type information.
- */
-static void
-image_pixel_convert_PLTE(image_pixel *this)
-{
- if (this->colour_type == PNG_COLOR_TYPE_PALETTE)
- {
- if (this->have_tRNS)
- {
- this->colour_type = PNG_COLOR_TYPE_RGB_ALPHA;
- this->have_tRNS = 0;
- }
- else
- this->colour_type = PNG_COLOR_TYPE_RGB;
-
- /* The bit depth of the row changes at this point too (notice that this is
- * the row format, not the sample depth, which is separate.)
- */
- this->bit_depth = 8;
- }
-}
-
-/* Add an alpha channel; this will import the tRNS information because tRNS is
- * not valid in an alpha image. The bit depth will invariably be set to at
- * least 8. Palette images will be converted to alpha (using the above API).
- */
-static void
-image_pixel_add_alpha(image_pixel *this, PNG_CONST standard_display *display)
-{
- if (this->colour_type == PNG_COLOR_TYPE_PALETTE)
- image_pixel_convert_PLTE(this);
-
- if ((this->colour_type & PNG_COLOR_MASK_ALPHA) == 0)
- {
- if (this->colour_type == PNG_COLOR_TYPE_GRAY)
- {
- if (this->bit_depth < 8)
- this->bit_depth = 8;
-
- if (this->have_tRNS)
- {
- this->have_tRNS = 0;
-
- /* Check the input, original, channel value here against the
- * original tRNS gray chunk valie.
- */
- if (this->red == display->transparent.red)
- this->alphaf = 0;
- else
- this->alphaf = 1;
- }
- else
- this->alphaf = 1;
-
- this->colour_type = PNG_COLOR_TYPE_GRAY_ALPHA;
- }
-
- else if (this->colour_type == PNG_COLOR_TYPE_RGB)
- {
- if (this->have_tRNS)
- {
- this->have_tRNS = 0;
-
- /* Again, check the exact input values, not the current transformed
- * value!
- */
- if (this->red == display->transparent.red &&
- this->green == display->transparent.green &&
- this->blue == display->transparent.blue)
- this->alphaf = 0;
- else
- this->alphaf = 1;
-
- this->colour_type = PNG_COLOR_TYPE_RGB_ALPHA;
- }
- }
-
- /* The error in the alpha is zero and the sBIT value comes from the
- * original sBIT data (actually it will always be the original bit depth).
- */
- this->alphae = 0;
- this->alpha_sBIT = display->alpha_sBIT;
- }
-}
-
-struct transform_display;
-typedef struct image_transform
-{
- /* The name of this transform: a string. */
- PNG_CONST char *name;
-
- /* Each transform can be disabled from the command line: */
- int enable;
-
- /* The global list of transforms; read only. */
- struct image_transform *PNG_CONST list;
-
- /* The global count of the number of times this transform has been set on an
- * image.
- */
- unsigned int global_use;
-
- /* The local count of the number of times this transform has been set. */
- unsigned int local_use;
-
- /* The next transform in the list, each transform must call its own next
- * transform after it has processed the pixel successfully.
- */
- PNG_CONST struct image_transform *next;
-
- /* A single transform for the image, expressed as a series of function
- * callbacks and some space for values.
- *
- * First a callback to add any required modifications to the png_modifier;
- * this gets called just before the modifier is set up for read.
- */
- void (*ini)(PNG_CONST struct image_transform *this,
- struct transform_display *that);
-
- /* And a callback to set the transform on the current png_read_struct:
- */
- void (*set)(PNG_CONST struct image_transform *this,
- struct transform_display *that, png_structp pp, png_infop pi);
-
- /* Then a transform that takes an input pixel in one PNG format or another
- * and modifies it by a pngvalid implementation of the transform (thus
- * duplicating the libpng intent without, we hope, duplicating the bugs
- * in the libpng implementation!) The png_structp is solely to allow error
- * reporting via png_error and png_warning.
- */
- void (*mod)(PNG_CONST struct image_transform *this, image_pixel *that,
- png_structp pp, PNG_CONST struct transform_display *display);
-
- /* Add this transform to the list and return true if the transform is
- * meaningful for this colour type and bit depth - if false then the
- * transform should have no effect on the image so there's not a lot of
- * point running it.
- */
- int (*add)(struct image_transform *this,
- PNG_CONST struct image_transform **that, png_byte colour_type,
- png_byte bit_depth);
-} image_transform;
-
-typedef struct transform_display
-{
- standard_display this;
-
- /* Parameters */
- png_modifier* pm;
- PNG_CONST image_transform* transform_list;
-
- /* Local variables */
- png_byte output_colour_type;
- png_byte output_bit_depth;
-
- /* Modifications (not necessarily used.) */
- gama_modification gama_mod;
- chrm_modification chrm_mod;
- srgb_modification srgb_mod;
-} transform_display;
-
-/* Set sRGB, cHRM and gAMA transforms as required by the current encoding. */
-static void
-transform_set_encoding(transform_display *this)
-{
- /* Set up the png_modifier '_current' fields then use these to determine how
- * to add appropriate chunks.
- */
- png_modifier *pm = this->pm;
-
- modifier_set_encoding(pm);
-
- if (modifier_color_encoding_is_set(pm))
- {
- if (modifier_color_encoding_is_sRGB(pm))
- srgb_modification_init(&this->srgb_mod, pm, PNG_sRGB_INTENT_ABSOLUTE);
-
- else
- {
- /* Set gAMA and cHRM separately. */
- gama_modification_init(&this->gama_mod, pm, pm->current_gamma);
-
- if (pm->current_encoding != 0)
- chrm_modification_init(&this->chrm_mod, pm, pm->current_encoding);
- }
- }
-}
-
-/* Three functions to end the list: */
-static void
-image_transform_ini_end(PNG_CONST image_transform *this,
- transform_display *that)
-{
- UNUSED(this)
- UNUSED(that)
-}
-
-static void
-image_transform_set_end(PNG_CONST image_transform *this,
- transform_display *that, png_structp pp, png_infop pi)
-{
- UNUSED(this)
- UNUSED(that)
- UNUSED(pp)
- UNUSED(pi)
-}
-
-/* At the end of the list recalculate the output image pixel value from the
- * double precision values set up by the preceding 'mod' calls:
- */
-static unsigned int
-sample_scale(double sample_value, unsigned int scale)
-{
- sample_value = floor(sample_value * scale + .5);
-
- /* Return NaN as 0: */
- if (!(sample_value > 0))
- sample_value = 0;
- else if (sample_value > scale)
- sample_value = scale;
-
- return (unsigned int)sample_value;
-}
-
-static void
-image_transform_mod_end(PNG_CONST image_transform *this, image_pixel *that,
- png_structp pp, PNG_CONST transform_display *display)
-{
- PNG_CONST unsigned int scale = (1U<<that->sample_depth)-1;
-
- UNUSED(this)
- UNUSED(pp)
- UNUSED(display)
-
- /* At the end recalculate the digitized red green and blue values according
- * to the current sample_depth of the pixel.
- *
- * The sample value is simply scaled to the maximum, checking for over
- * and underflow (which can both happen for some image transforms,
- * including simple size scaling, though libpng doesn't do that at present.
- */
- that->red = sample_scale(that->redf, scale);
-
- /* The error value is increased, at the end, according to the lowest sBIT
- * value seen. Common sense tells us that the intermediate integer
- * representations are no more accurate than +/- 0.5 in the integral values,
- * the sBIT allows the implementation to be worse than this. In addition the
- * PNG specification actually permits any error within the range (-1..+1),
- * but that is ignored here. Instead the final digitized value is compared,
- * below to the digitized value of the error limits - this has the net effect
- * of allowing (almost) +/-1 in the output value. It's difficult to see how
- * any algorithm that digitizes intermediate results can be more accurate.
- */
- that->rede += 1./(2*((1U<<that->red_sBIT)-1));
-
- if (that->colour_type & PNG_COLOR_MASK_COLOR)
- {
- that->green = sample_scale(that->greenf, scale);
- that->blue = sample_scale(that->bluef, scale);
- that->greene += 1./(2*((1U<<that->green_sBIT)-1));
- that->bluee += 1./(2*((1U<<that->blue_sBIT)-1));
- }
- else
- {
- that->blue = that->green = that->red;
- that->bluef = that->greenf = that->redf;
- that->bluee = that->greene = that->rede;
- }
-
- if ((that->colour_type & PNG_COLOR_MASK_ALPHA) ||
- that->colour_type == PNG_COLOR_TYPE_PALETTE)
- {
- that->alpha = sample_scale(that->alphaf, scale);
- that->alphae += 1./(2*((1U<<that->alpha_sBIT)-1));
- }
- else
- {
- that->alpha = scale; /* opaque */
- that->alpha = 1; /* Override this. */
- that->alphae = 0; /* It's exact ;-) */
- }
-}
-
-/* Static 'end' structure: */
-static image_transform image_transform_end =
-{
- "(end)", /* name */
- 1, /* enable */
- 0, /* list */
- 0, /* global_use */
- 0, /* local_use */
- 0, /* next */
- image_transform_ini_end,
- image_transform_set_end,
- image_transform_mod_end,
- 0 /* never called, I want it to crash if it is! */
-};
-
-/* Reader callbacks and implementations, where they differ from the standard
- * ones.
- */
-static void
-transform_display_init(transform_display *dp, png_modifier *pm, png_uint_32 id,
- PNG_CONST image_transform *transform_list)
-{
- memset(dp, 0, sizeof dp);
-
- /* Standard fields */
- standard_display_init(&dp->this, &pm->this, id, 0/*do_interlace*/,
- pm->use_update_info);
-
- /* Parameter fields */
- dp->pm = pm;
- dp->transform_list = transform_list;
-
- /* Local variable fields */
- dp->output_colour_type = 255; /* invalid */
- dp->output_bit_depth = 255; /* invalid */
-}
-
-static void
-transform_info_imp(transform_display *dp, png_structp pp, png_infop pi)
-{
- /* Reuse the standard stuff as appropriate. */
- standard_info_part1(&dp->this, pp, pi);
-
- /* Now set the list of transforms. */
- dp->transform_list->set(dp->transform_list, dp, pp, pi);
-
- /* Update the info structure for these transforms: */
- {
- int i = dp->this.use_update_info;
- /* Always do one call, even if use_update_info is 0. */
- do
- png_read_update_info(pp, pi);
- while (--i > 0);
- }
-
- /* And get the output information into the standard_display */
- standard_info_part2(&dp->this, pp, pi, 1/*images*/);
-
- /* Plus the extra stuff we need for the transform tests: */
- dp->output_colour_type = png_get_color_type(pp, pi);
- dp->output_bit_depth = png_get_bit_depth(pp, pi);
-
- /* Validate the combination of colour type and bit depth that we are getting
- * out of libpng; the semantics of something not in the PNG spec are, at
- * best, unclear.
- */
- switch (dp->output_colour_type)
- {
- case PNG_COLOR_TYPE_PALETTE:
- if (dp->output_bit_depth > 8) goto error;
- /*FALL THROUGH*/
- case PNG_COLOR_TYPE_GRAY:
- if (dp->output_bit_depth == 1 || dp->output_bit_depth == 2 ||
- dp->output_bit_depth == 4)
- break;
- /*FALL THROUGH*/
- default:
- if (dp->output_bit_depth == 8 || dp->output_bit_depth == 16)
- break;
- /*FALL THROUGH*/
- error:
- {
- char message[128];
- size_t pos;
-
- pos = safecat(message, sizeof message, 0,
- "invalid final bit depth: colour type(");
- pos = safecatn(message, sizeof message, pos, dp->output_colour_type);
- pos = safecat(message, sizeof message, pos, ") with bit depth: ");
- pos = safecatn(message, sizeof message, pos, dp->output_bit_depth);
-
- png_error(pp, message);
- }
- }
-
- /* Use a test pixel to check that the output agrees with what we expect -
- * this avoids running the whole test if the output is unexpected.
- */
- {
- image_pixel test_pixel;
-
- memset(&test_pixel, 0, sizeof test_pixel);
- test_pixel.colour_type = dp->this.colour_type; /* input */
- test_pixel.bit_depth = dp->this.bit_depth;
- if (test_pixel.colour_type == PNG_COLOR_TYPE_PALETTE)
- test_pixel.sample_depth = 8;
- else
- test_pixel.sample_depth = test_pixel.bit_depth;
- /* Don't need sBIT here */
- test_pixel.have_tRNS = dp->this.is_transparent;
-
- dp->transform_list->mod(dp->transform_list, &test_pixel, pp, dp);
-
- if (test_pixel.colour_type != dp->output_colour_type)
- {
- char message[128];
- size_t pos = safecat(message, sizeof message, 0, "colour type ");
-
- pos = safecatn(message, sizeof message, pos, dp->output_colour_type);
- pos = safecat(message, sizeof message, pos, " expected ");
- pos = safecatn(message, sizeof message, pos, test_pixel.colour_type);
-
- png_error(pp, message);
- }
-
- if (test_pixel.bit_depth != dp->output_bit_depth)
- {
- char message[128];
- size_t pos = safecat(message, sizeof message, 0, "bit depth ");
-
- pos = safecatn(message, sizeof message, pos, dp->output_bit_depth);
- pos = safecat(message, sizeof message, pos, " expected ");
- pos = safecatn(message, sizeof message, pos, test_pixel.bit_depth);
-
- png_error(pp, message);
- }
-
- /* If both bit depth and colour type are correct check the sample depth.
- * I believe these are both internal errors.
- */
- if (test_pixel.colour_type == PNG_COLOR_TYPE_PALETTE)
- {
- if (test_pixel.sample_depth != 8) /* oops - internal error! */
- png_error(pp, "pngvalid: internal: palette sample depth not 8");
- }
- else if (test_pixel.sample_depth != dp->output_bit_depth)
- {
- char message[128];
- size_t pos = safecat(message, sizeof message, 0,
- "internal: sample depth ");
-
- pos = safecatn(message, sizeof message, pos, dp->output_bit_depth);
- pos = safecat(message, sizeof message, pos, " expected ");
- pos = safecatn(message, sizeof message, pos, test_pixel.sample_depth);
-
- png_error(pp, message);
- }
- }
-}
-
-static void
-transform_info(png_structp pp, png_infop pi)
-{
- transform_info_imp(voidcast(transform_display*, png_get_progressive_ptr(pp)),
- pp, pi);
-}
-
-static void
-transform_range_check(png_structp pp, unsigned int r, unsigned int g,
- unsigned int b, unsigned int a, unsigned int in_digitized, double in,
- unsigned int out, png_byte sample_depth, double err, double limit,
- PNG_CONST char *name, double digitization_error)
-{
- /* Compare the scaled, digitzed, values of our local calculation (in+-err)
- * with the digitized values libpng produced; 'sample_depth' is the actual
- * digitization depth of the libpng output colors (the bit depth except for
- * palette images where it is always 8.) The check on 'err' is to detect
- * internal errors in pngvalid itself.
- */
- unsigned int max = (1U<<sample_depth)-1;
- double in_min = ceil((in-err)*max - digitization_error);
- double in_max = floor((in+err)*max + digitization_error);
- if (err > limit || !(out >= in_min && out <= in_max))
- {
- char message[256];
- size_t pos;
-
- pos = safecat(message, sizeof message, 0, name);
- pos = safecat(message, sizeof message, pos, " output value error: rgba(");
- pos = safecatn(message, sizeof message, pos, r);
- pos = safecat(message, sizeof message, pos, ",");
- pos = safecatn(message, sizeof message, pos, g);
- pos = safecat(message, sizeof message, pos, ",");
- pos = safecatn(message, sizeof message, pos, b);
- pos = safecat(message, sizeof message, pos, ",");
- pos = safecatn(message, sizeof message, pos, a);
- pos = safecat(message, sizeof message, pos, "): ");
- pos = safecatn(message, sizeof message, pos, out);
- pos = safecat(message, sizeof message, pos, " expected: ");
- pos = safecatn(message, sizeof message, pos, in_digitized);
- pos = safecat(message, sizeof message, pos, " (");
- pos = safecatd(message, sizeof message, pos, (in-err)*max, 3);
- pos = safecat(message, sizeof message, pos, "..");
- pos = safecatd(message, sizeof message, pos, (in+err)*max, 3);
- pos = safecat(message, sizeof message, pos, ")");
-
- png_error(pp, message);
- }
-}
-
-static void
-transform_image_validate(transform_display *dp, png_structp pp, png_infop pi)
-{
- /* Constants for the loop below: */
- PNG_CONST png_store* PNG_CONST ps = dp->this.ps;
- PNG_CONST png_byte in_ct = dp->this.colour_type;
- PNG_CONST png_byte in_bd = dp->this.bit_depth;
- PNG_CONST png_uint_32 w = dp->this.w;
- PNG_CONST png_uint_32 h = dp->this.h;
- PNG_CONST png_byte out_ct = dp->output_colour_type;
- PNG_CONST png_byte out_bd = dp->output_bit_depth;
- PNG_CONST png_byte sample_depth = (png_byte)(out_ct ==
- PNG_COLOR_TYPE_PALETTE ? 8 : out_bd);
- PNG_CONST png_byte red_sBIT = dp->this.red_sBIT;
- PNG_CONST png_byte green_sBIT = dp->this.green_sBIT;
- PNG_CONST png_byte blue_sBIT = dp->this.blue_sBIT;
- PNG_CONST png_byte alpha_sBIT = dp->this.alpha_sBIT;
- PNG_CONST int have_tRNS = dp->this.is_transparent;
- double digitization_error;
-
- store_palette out_palette;
- png_uint_32 y;
-
- UNUSED(pi)
-
- /* Check for row overwrite errors */
- store_image_check(dp->this.ps, pp, 0);
-
- /* Read the palette corresponding to the output if the output colour type
- * indicates a palette, othewise set out_palette to garbage.
- */
- if (out_ct == PNG_COLOR_TYPE_PALETTE)
- {
- /* Validate that the palette count itself has not changed - this is not
- * expected.
- */
- int npalette = (-1);
-
- (void)read_palette(out_palette, &npalette, pp, pi);
- if (npalette != dp->this.npalette)
- png_error(pp, "unexpected change in palette size");
-
- digitization_error = .5;
- }
- else
- {
- png_byte in_sample_depth;
-
- memset(out_palette, 0x5e, sizeof out_palette);
-
- /* assume-8-bit-calculations means assume that if the input has 8 bit
- * (or less) samples and the output has 16 bit samples the calculations
- * will be done with 8 bit precision, not 16.
- *
- * TODO: fix this in libpng; png_set_expand_16 should cause 16 bit
- * calculations to be used throughout.
- */
- if (in_ct == PNG_COLOR_TYPE_PALETTE || in_bd < 16)
- in_sample_depth = 8;
- else
- in_sample_depth = in_bd;
-
- if (sample_depth != 16 || in_sample_depth > 8 ||
- !dp->pm->calculations_use_input_precision)
- digitization_error = .5;
-
- /* Else errors are at 8 bit precision, scale .5 in 8 bits to the 16 bits:
- */
- else
- digitization_error = .5 * 257;
- }
-
- for (y=0; y<h; ++y)
- {
- png_const_bytep PNG_CONST pRow = store_image_row(ps, pp, 0, y);
- png_uint_32 x;
-
- /* The original, standard, row pre-transforms. */
- png_byte std[STANDARD_ROWMAX];
-
- transform_row(pp, std, in_ct, in_bd, y);
-
- /* Go through each original pixel transforming it and comparing with what
- * libpng did to the same pixel.
- */
- for (x=0; x<w; ++x)
- {
- image_pixel in_pixel, out_pixel;
- unsigned int r, g, b, a;
-
- /* Find out what we think the pixel should be: */
- image_pixel_init(&in_pixel, std, in_ct, in_bd, x, dp->this.palette);
-
- in_pixel.red_sBIT = red_sBIT;
- in_pixel.green_sBIT = green_sBIT;
- in_pixel.blue_sBIT = blue_sBIT;
- in_pixel.alpha_sBIT = alpha_sBIT;
- in_pixel.have_tRNS = have_tRNS;
-
- /* For error detection, below. */
- r = in_pixel.red;
- g = in_pixel.green;
- b = in_pixel.blue;
- a = in_pixel.alpha;
-
- dp->transform_list->mod(dp->transform_list, &in_pixel, pp, dp);
-
- /* Read the output pixel and compare it to what we got, we don't
- * use the error field here, so no need to update sBIT.
- */
- image_pixel_init(&out_pixel, pRow, out_ct, out_bd, x, out_palette);
-
- /* We don't expect changes to the index here even if the bit depth is
- * changed.
- */
- if (in_ct == PNG_COLOR_TYPE_PALETTE &&
- out_ct == PNG_COLOR_TYPE_PALETTE)
- {
- if (in_pixel.palette_index != out_pixel.palette_index)
- png_error(pp, "unexpected transformed palette index");
- }
-
- /* Check the colours for palette images too - in fact the palette could
- * be separately verified itself in most cases.
- */
- if (in_pixel.red != out_pixel.red)
- transform_range_check(pp, r, g, b, a, in_pixel.red, in_pixel.redf,
- out_pixel.red, sample_depth, in_pixel.rede,
- dp->pm->limit + 1./(2*((1U<<in_pixel.red_sBIT)-1)), "red/gray",
- digitization_error);
-
- if ((out_ct & PNG_COLOR_MASK_COLOR) != 0 &&
- in_pixel.green != out_pixel.green)
- transform_range_check(pp, r, g, b, a, in_pixel.green,
- in_pixel.greenf, out_pixel.green, sample_depth, in_pixel.greene,
- dp->pm->limit + 1./(2*((1U<<in_pixel.green_sBIT)-1)), "green",
- digitization_error);
-
- if ((out_ct & PNG_COLOR_MASK_COLOR) != 0 &&
- in_pixel.blue != out_pixel.blue)
- transform_range_check(pp, r, g, b, a, in_pixel.blue, in_pixel.bluef,
- out_pixel.blue, sample_depth, in_pixel.bluee,
- dp->pm->limit + 1./(2*((1U<<in_pixel.blue_sBIT)-1)), "blue",
- digitization_error);
-
- if ((out_ct & PNG_COLOR_MASK_ALPHA) != 0 &&
- in_pixel.alpha != out_pixel.alpha)
- transform_range_check(pp, r, g, b, a, in_pixel.alpha,
- in_pixel.alphaf, out_pixel.alpha, sample_depth, in_pixel.alphae,
- dp->pm->limit + 1./(2*((1U<<in_pixel.alpha_sBIT)-1)), "alpha",
- digitization_error);
- } /* pixel (x) loop */
- } /* row (y) loop */
-
- /* Record that something was actually checked to avoid a false positive. */
- dp->this.ps->validated = 1;
-}
-
-static void
-transform_end(png_structp pp, png_infop pi)
-{
- transform_display *dp = voidcast(transform_display*,
- png_get_progressive_ptr(pp));
-
- if (!dp->this.speed)
- transform_image_validate(dp, pp, pi);
- else
- dp->this.ps->validated = 1;
-}
-
-/* A single test run. */
-static void
-transform_test(png_modifier *pmIn, PNG_CONST png_uint_32 idIn,
- PNG_CONST image_transform* transform_listIn, PNG_CONST char * volatile name)
-{
- transform_display d;
- context(&pmIn->this, fault);
-
- transform_display_init(&d, pmIn, idIn, transform_listIn);
-
- Try
- {
- size_t pos = 0;
- png_structp pp;
- png_infop pi;
- char full_name[256];
-
- /* Make sure the encoding fields are correct and enter the required
- * modifications.
- */
- transform_set_encoding(&d);
-
- /* Add any modifications required by the transform list. */
- d.transform_list->ini(d.transform_list, &d);
-
- /* Add the color space information, if any, to the name. */
- pos = safecat(full_name, sizeof full_name, pos, name);
- pos = safecat_current_encoding(full_name, sizeof full_name, pos, d.pm);
-
- /* Get a png_struct for reading the image. */
- pp = set_modifier_for_read(d.pm, &pi, d.this.id, full_name);
- standard_palette_init(&d.this);
-
-# if 0
- /* Logging (debugging only) */
- {
- char buffer[256];
-
- (void)store_message(&d.pm->this, pp, buffer, sizeof buffer, 0,
- "running test");
-
- fprintf(stderr, "%s\n", buffer);
- }
-# endif
-
- /* Introduce the correct read function. */
- if (d.pm->this.progressive)
- {
- /* Share the row function with the standard implementation. */
- png_set_progressive_read_fn(pp, &d, transform_info, progressive_row,
- transform_end);
-
- /* Now feed data into the reader until we reach the end: */
- modifier_progressive_read(d.pm, pp, pi);
- }
- else
- {
- /* modifier_read expects a png_modifier* */
- png_set_read_fn(pp, d.pm, modifier_read);
-
- /* Check the header values: */
- png_read_info(pp, pi);
-
- /* Process the 'info' requirements. Only one image is generated */
- transform_info_imp(&d, pp, pi);
-
- sequential_row(&d.this, pp, pi, -1, 0);
-
- if (!d.this.speed)
- transform_image_validate(&d, pp, pi);
- else
- d.this.ps->validated = 1;
- }
-
- modifier_reset(d.pm);
- }
-
- Catch(fault)
- {
- modifier_reset((png_modifier*)fault);
- }
-}
-
-/* The transforms: */
-#define ITSTRUCT(name) image_transform_##name
-#define ITDATA(name) image_transform_data_##name
-#define image_transform_ini image_transform_default_ini
-#define IT(name)\
-static image_transform ITSTRUCT(name) =\
-{\
- #name,\
- 1, /*enable*/\
- &PT, /*list*/\
- 0, /*global_use*/\
- 0, /*local_use*/\
- 0, /*next*/\
- image_transform_ini,\
- image_transform_png_set_##name##_set,\
- image_transform_png_set_##name##_mod,\
- image_transform_png_set_##name##_add\
-}
-#define PT ITSTRUCT(end) /* stores the previous transform */
-
-/* To save code: */
-static void
-image_transform_default_ini(PNG_CONST image_transform *this,
- transform_display *that)
-{
- this->next->ini(this->next, that);
-}
-
-static int
-image_transform_default_add(image_transform *this,
- PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
-{
- UNUSED(colour_type)
- UNUSED(bit_depth)
-
- this->next = *that;
- *that = this;
-
- return 1;
-}
-
-#ifdef PNG_READ_EXPAND_SUPPORTED
-/* png_set_palette_to_rgb */
-static void
-image_transform_png_set_palette_to_rgb_set(PNG_CONST image_transform *this,
- transform_display *that, png_structp pp, png_infop pi)
-{
- png_set_palette_to_rgb(pp);
- this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_palette_to_rgb_mod(PNG_CONST image_transform *this,
- image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
-{
- if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
- image_pixel_convert_PLTE(that);
-
- this->next->mod(this->next, that, pp, display);
-}
-
-static int
-image_transform_png_set_palette_to_rgb_add(image_transform *this,
- PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
-{
- UNUSED(bit_depth)
-
- this->next = *that;
- *that = this;
-
- return colour_type == PNG_COLOR_TYPE_PALETTE;
-}
-
-IT(palette_to_rgb);
-#undef PT
-#define PT ITSTRUCT(palette_to_rgb)
-#endif /* PNG_READ_EXPAND_SUPPORTED */
-
-#ifdef PNG_READ_EXPAND_SUPPORTED
-/* png_set_tRNS_to_alpha */
-static void
-image_transform_png_set_tRNS_to_alpha_set(PNG_CONST image_transform *this,
- transform_display *that, png_structp pp, png_infop pi)
-{
- png_set_tRNS_to_alpha(pp);
- this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_tRNS_to_alpha_mod(PNG_CONST image_transform *this,
- image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
-{
- /* LIBPNG BUG: this always forces palette images to RGB. */
- if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
- image_pixel_convert_PLTE(that);
-
- /* This effectively does an 'expand' only if there is some transparency to
- * convert to an alpha channel.
- */
- if (that->have_tRNS)
- image_pixel_add_alpha(that, &display->this);
-
- /* LIBPNG BUG: otherwise libpng still expands to 8 bits! */
- else
- {
- if (that->bit_depth < 8)
- that->bit_depth =8;
- if (that->sample_depth < 8)
- that->sample_depth = 8;
- }
-
- this->next->mod(this->next, that, pp, display);
-}
-
-static int
-image_transform_png_set_tRNS_to_alpha_add(image_transform *this,
- PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
-{
- UNUSED(bit_depth)
-
- this->next = *that;
- *that = this;
-
- /* We don't know yet whether there will be a tRNS chunk, but we know that
- * this transformation should do nothing if there already is an alpha
- * channel.
- */
- return (colour_type & PNG_COLOR_MASK_ALPHA) == 0;
-}
-
-IT(tRNS_to_alpha);
-#undef PT
-#define PT ITSTRUCT(tRNS_to_alpha)
-#endif /* PNG_READ_EXPAND_SUPPORTED */
-
-#ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
-/* png_set_gray_to_rgb */
-static void
-image_transform_png_set_gray_to_rgb_set(PNG_CONST image_transform *this,
- transform_display *that, png_structp pp, png_infop pi)
-{
- png_set_gray_to_rgb(pp);
- this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_gray_to_rgb_mod(PNG_CONST image_transform *this,
- image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
-{
- /* NOTE: we can actually pend the tRNS processing at this point because we
- * can correctly recognize the original pixel value even though we have
- * mapped the one gray channel to the three RGB ones, but in fact libpng
- * doesn't do this, so we don't either.
- */
- if ((that->colour_type & PNG_COLOR_MASK_COLOR) == 0 && that->have_tRNS)
- image_pixel_add_alpha(that, &display->this);
-
- /* Simply expand the bit depth and alter the colour type as required. */
- if (that->colour_type == PNG_COLOR_TYPE_GRAY)
- {
- /* RGB images have a bit depth at least equal to '8' */
- if (that->bit_depth < 8)
- that->sample_depth = that->bit_depth = 8;
-
- /* And just changing the colour type works here because the green and blue
- * channels are being maintained in lock-step with the red/gray:
- */
- that->colour_type = PNG_COLOR_TYPE_RGB;
- }
-
- else if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA)
- that->colour_type = PNG_COLOR_TYPE_RGB_ALPHA;
-
- this->next->mod(this->next, that, pp, display);
-}
-
-static int
-image_transform_png_set_gray_to_rgb_add(image_transform *this,
- PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
-{
- UNUSED(bit_depth)
-
- this->next = *that;
- *that = this;
-
- return (colour_type & PNG_COLOR_MASK_COLOR) == 0;
-}
-
-IT(gray_to_rgb);
-#undef PT
-#define PT ITSTRUCT(gray_to_rgb)
-#endif /* PNG_READ_GRAY_TO_RGB_SUPPORTED */
-
-#ifdef PNG_READ_EXPAND_SUPPORTED
-/* png_set_expand */
-static void
-image_transform_png_set_expand_set(PNG_CONST image_transform *this,
- transform_display *that, png_structp pp, png_infop pi)
-{
- png_set_expand(pp);
- this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_expand_mod(PNG_CONST image_transform *this,
- image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
-{
- /* The general expand case depends on what the colour type is: */
- if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
- image_pixel_convert_PLTE(that);
- else if (that->bit_depth < 8) /* grayscale */
- that->sample_depth = that->bit_depth = 8;
-
- if (that->have_tRNS)
- image_pixel_add_alpha(that, &display->this);
-
- this->next->mod(this->next, that, pp, display);
-}
-
-static int
-image_transform_png_set_expand_add(image_transform *this,
- PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
-{
- UNUSED(bit_depth)
-
- this->next = *that;
- *that = this;
-
- /* 'expand' should do nothing for RGBA or GA input - no tRNS and the bit
- * depth is at least 8 already.
- */
- return (colour_type & PNG_COLOR_MASK_ALPHA) == 0;
-}
-
-IT(expand);
-#undef PT
-#define PT ITSTRUCT(expand)
-#endif /* PNG_READ_EXPAND_SUPPORTED */
-
-#ifdef PNG_READ_EXPAND_SUPPORTED
-/* png_set_expand_gray_1_2_4_to_8
- * LIBPNG BUG: this just does an 'expand'
- */
-static void
-image_transform_png_set_expand_gray_1_2_4_to_8_set(
- PNG_CONST image_transform *this, transform_display *that, png_structp pp,
- png_infop pi)
-{
- png_set_expand_gray_1_2_4_to_8(pp);
- this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_expand_gray_1_2_4_to_8_mod(
- PNG_CONST image_transform *this, image_pixel *that, png_structp pp,
- PNG_CONST transform_display *display)
-{
- image_transform_png_set_expand_mod(this, that, pp, display);
-}
-
-static int
-image_transform_png_set_expand_gray_1_2_4_to_8_add(image_transform *this,
- PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
-{
- return image_transform_png_set_expand_add(this, that, colour_type,
- bit_depth);
-}
-
-IT(expand_gray_1_2_4_to_8);
-#undef PT
-#define PT ITSTRUCT(expand_gray_1_2_4_to_8)
-#endif /* PNG_READ_EXPAND_SUPPORTED */
-
-#ifdef PNG_READ_EXPAND_16_SUPPORTED
-/* png_set_expand_16 */
-static void
-image_transform_png_set_expand_16_set(PNG_CONST image_transform *this,
- transform_display *that, png_structp pp, png_infop pi)
-{
- png_set_expand_16(pp);
- this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_expand_16_mod(PNG_CONST image_transform *this,
- image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
-{
- /* Expect expand_16 to expand everything to 16 bits as a result of also
- * causing 'expand' to happen.
- */
- if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
- image_pixel_convert_PLTE(that);
-
- if (that->have_tRNS)
- image_pixel_add_alpha(that, &display->this);
-
- if (that->bit_depth < 16)
- that->sample_depth = that->bit_depth = 16;
-
- this->next->mod(this->next, that, pp, display);
-}
-
-static int
-image_transform_png_set_expand_16_add(image_transform *this,
- PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
-{
- UNUSED(colour_type)
-
- this->next = *that;
- *that = this;
-
- /* expand_16 does something unless the bit depth is already 16. */
- return bit_depth < 16;
-}
-
-IT(expand_16);
-#undef PT
-#define PT ITSTRUCT(expand_16)
-#endif /* PNG_READ_EXPAND_16_SUPPORTED */
-
-#ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED /* API added in 1.5.4 */
-/* png_set_scale_16 */
-static void
-image_transform_png_set_scale_16_set(PNG_CONST image_transform *this,
- transform_display *that, png_structp pp, png_infop pi)
-{
- png_set_scale_16(pp);
- this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_scale_16_mod(PNG_CONST image_transform *this,
- image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
-{
- if (that->bit_depth == 16)
- {
- that->sample_depth = that->bit_depth = 8;
- if (that->red_sBIT > 8) that->red_sBIT = 8;
- if (that->green_sBIT > 8) that->green_sBIT = 8;
- if (that->blue_sBIT > 8) that->blue_sBIT = 8;
- if (that->alpha_sBIT > 8) that->alpha_sBIT = 8;
- }
-
- this->next->mod(this->next, that, pp, display);
-}
-
-static int
-image_transform_png_set_scale_16_add(image_transform *this,
- PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
-{
- UNUSED(colour_type)
-
- this->next = *that;
- *that = this;
-
- return bit_depth > 8;
-}
-
-IT(scale_16);
-#undef PT
-#define PT ITSTRUCT(scale_16)
-#endif /* PNG_READ_SCALE_16_TO_8_SUPPORTED (1.5.4 on) */
-
-#ifdef PNG_READ_16_TO_8_SUPPORTED /* the default before 1.5.4 */
-/* png_set_strip_16 */
-static void
-image_transform_png_set_strip_16_set(PNG_CONST image_transform *this,
- transform_display *that, png_structp pp, png_infop pi)
-{
- png_set_strip_16(pp);
- this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_strip_16_mod(PNG_CONST image_transform *this,
- image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
-{
- if (that->bit_depth == 16)
- {
- that->sample_depth = that->bit_depth = 8;
- if (that->red_sBIT > 8) that->red_sBIT = 8;
- if (that->green_sBIT > 8) that->green_sBIT = 8;
- if (that->blue_sBIT > 8) that->blue_sBIT = 8;
- if (that->alpha_sBIT > 8) that->alpha_sBIT = 8;
-
- /* Prior to 1.5.4 png_set_strip_16 would use an 'accurate' method if this
- * configuration option is set. From 1.5.4 the flag is never set and the
- * 'scale' API (above) must be used.
- */
-# ifdef PNG_READ_ACCURATE_SCALE_SUPPORTED
-# if PNG_LIBPNG_VER >= 10504
-# error PNG_READ_ACCURATE_SCALE should not be set
-# endif
-
- /* The strip 16 algorithm drops the low 8 bits rather than calculating
- * 1/257, so we need to adjust the permitted errors appropriately:
- * Notice that this is only relevant prior to the addition of the
- * png_set_scale_16 API in 1.5.4 (but 1.5.4+ always defines the above!)
- */
- {
- PNG_CONST double d = (255-128.5)/65535;
- that->rede += d;
- that->greene += d;
- that->bluee += d;
- that->alphae += d;
- }
-# endif
- }
-
- this->next->mod(this->next, that, pp, display);
-}
-
-static int
-image_transform_png_set_strip_16_add(image_transform *this,
- PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
-{
- UNUSED(colour_type)
-
- this->next = *that;
- *that = this;
-
- return bit_depth > 8;
-}
-
-IT(strip_16);
-#undef PT
-#define PT ITSTRUCT(strip_16)
-#endif /* PNG_READ_16_TO_8_SUPPORTED */
-
-#ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
-/* png_set_strip_alpha */
-static void
-image_transform_png_set_strip_alpha_set(PNG_CONST image_transform *this,
- transform_display *that, png_structp pp, png_infop pi)
-{
- png_set_strip_alpha(pp);
- this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_strip_alpha_mod(PNG_CONST image_transform *this,
- image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
-{
- if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA)
- that->colour_type = PNG_COLOR_TYPE_GRAY;
- else if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA)
- that->colour_type = PNG_COLOR_TYPE_RGB;
-
- that->have_tRNS = 0;
- that->alphaf = 1;
-
- this->next->mod(this->next, that, pp, display);
-}
-
-static int
-image_transform_png_set_strip_alpha_add(image_transform *this,
- PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
-{
- UNUSED(bit_depth)
-
- this->next = *that;
- *that = this;
-
- return (colour_type & PNG_COLOR_MASK_ALPHA) != 0;
-}
-
-IT(strip_alpha);
-#undef PT
-#define PT ITSTRUCT(strip_alpha)
-#endif /* PNG_READ_STRIP_ALPHA_SUPPORTED */
-
-#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
-/* png_set_rgb_to_gray(png_structp, int err_action, double red, double green)
- * png_set_rgb_to_gray_fixed(png_structp, int err_action, png_fixed_point red,
- * png_fixed_point green)
- * png_get_rgb_to_gray_status
- *
- * The 'default' test here uses values known to be used inside libpng:
- *
- * red: 6968
- * green: 23434
- * blue: 2366
- *
- * These values are being retained for compatibility, along with the somewhat
- * broken truncation calculation in the fast-and-inaccurate code path. Older
- * versions of libpng will fail the accuracy tests below because they use the
- * truncation algorithm everywhere.
- */
-#define data ITDATA(rgb_to_gray)
-static struct
-{
- double gamma; /* File gamma to use in processing */
-
- /* The following are the parameters for png_set_rgb_to_gray: */
-# ifdef PNG_FLOATING_POINT_SUPPORTED
- double red_to_set;
- double green_to_set;
-# else
- png_fixed_point red_to_set;
- png_fixed_point green_to_set;
-# endif
-
- /* The actual coefficients: */
- double red_coefficient;
- double green_coefficient;
- double blue_coefficient;
-
- /* Set if the coeefficients have been overridden. */
- int coefficients_overridden;
-} data;
-
-#undef image_transform_ini
-#define image_transform_ini image_transform_png_set_rgb_to_gray_ini
-static void
-image_transform_png_set_rgb_to_gray_ini(PNG_CONST image_transform *this,
- transform_display *that)
-{
- png_modifier *pm = that->pm;
- PNG_CONST color_encoding *e = pm->current_encoding;
-
- UNUSED(this)
-
- /* Since we check the encoding this flag must be set: */
- pm->test_uses_encoding = 1;
-
- /* If 'e' is not NULL chromaticity information is present and either a cHRM
- * or an sRGB chunk will be inserted.
- */
- if (e != 0)
- {
- /* Coefficients come from the encoding, but may need to be normalized to a
- * white point Y of 1.0
- */
- PNG_CONST double whiteY = e->red.Y + e->green.Y + e->blue.Y;
-
- data.red_coefficient = e->red.Y;
- data.green_coefficient = e->green.Y;
- data.blue_coefficient = e->blue.Y;
-
- if (whiteY != 1)
- {
- data.red_coefficient /= whiteY;
- data.green_coefficient /= whiteY;
- data.blue_coefficient /= whiteY;
- }
- }
-
- else
- {
- /* The default (built in) coeffcients, as above: */
- data.red_coefficient = 6968 / 32768.;
- data.green_coefficient = 23434 / 32768.;
- data.blue_coefficient = 2366 / 32768.;
- }
-
- data.gamma = pm->current_gamma;
-
- /* If not set then the calculations assume linear encoding (implicitly): */
- if (data.gamma == 0)
- data.gamma = 1;
-
- /* The arguments to png_set_rgb_to_gray can override the coefficients implied
- * by the color space encoding. If doing exhaustive checks do the override
- * in each case, otherwise do it randomly.
- */
- if (pm->test_exhaustive)
- {
- /* First time in coefficients_overridden is 0, the following sets it to 1,
- * so repeat if it is set. If a test fails this may mean we subsequently
- * skip a non-override test, ignore that.
- */
- data.coefficients_overridden = !data.coefficients_overridden;
- pm->repeat = data.coefficients_overridden != 0;
- }
-
- else
- data.coefficients_overridden = random_choice();
-
- if (data.coefficients_overridden)
- {
- /* These values override the color encoding defaults, simply use random
- * numbers.
- */
- png_uint_32 ru;
- double total;
-
- RANDOMIZE(ru);
- data.green_coefficient = total = (ru & 0xffff) / 65535.;
- ru >>= 16;
- data.red_coefficient = (1 - total) * (ru & 0xffff) / 65535.;
- total += data.red_coefficient;
- data.blue_coefficient = 1 - total;
-
-# ifdef PNG_FLOATING_POINT_SUPPORTED
- data.red_to_set = data.red_coefficient;
- data.green_to_set = data.green_coefficient;
-# else
- data.red_to_set = fix(data.red_coefficient);
- data.green_to_set = fix(data.green_coefficient);
-# endif
-
- /* The following just changes the error messages: */
- pm->encoding_ignored = 1;
- }
-
- else
- {
- data.red_to_set = -1;
- data.green_to_set = -1;
- }
-
- /* Adjust the error limit in the png_modifier because of the larger errors
- * produced in the digitization during the gamma handling.
- */
- if (data.gamma != 1) /* Use gamma tables */
- {
- if (that->this.bit_depth == 16 || pm->assume_16_bit_calculations)
- {
- /* The 16 bit case ends up producing a maximum error of about
- * +/-5 in 65535, allow for +/-8 with the given gamma.
- */
- that->pm->limit += pow(8./65535, data.gamma);
- }
-
- else
- {
- /* Rounding to 8 bits in the linear space causes massive errors which
- * will trigger the error check in transform_range_check. Fix that
- * here by taking the gamma encoding into account.
- */
- that->pm->limit += pow(1./255, data.gamma);
- }
- }
-
- else
- {
- /* With no gamma correction a large error comes from the truncation of the
- * calculation in the 8 bit case, allow for that here.
- */
- if (that->this.bit_depth != 16)
- that->pm->limit += 4E-3;
- }
-}
-
-static void
-image_transform_png_set_rgb_to_gray_set(PNG_CONST image_transform *this,
- transform_display *that, png_structp pp, png_infop pi)
-{
- PNG_CONST int error_action = 1; /* no error, no defines in png.h */
-
-# ifdef PNG_FLOATING_POINT_SUPPORTED
- png_set_rgb_to_gray(pp, error_action, data.red_to_set, data.green_to_set);
-# else
- png_set_rgb_to_gray_fixed(pp, error_action, data.red_to_set,
- data.green_to_set);
-# endif
-
-# ifdef PNG_READ_cHRM_SUPPORTED
- if (that->pm->current_encoding != 0)
- {
- /* We have an encoding so a cHRM chunk may have been set; if so then
- * check that the libpng APIs give the correct (X,Y,Z) values within
- * some margin of error for the round trip through the chromaticity
- * form.
- */
-# ifdef PNG_FLOATING_POINT_SUPPORTED
-# define API_function png_get_cHRM_XYZ
-# define API_form "FP"
-# define API_type double
-# define API_cvt(x) (x)
-# else
-# define API_function png_get_cHRM_XYZ_fixed
-# define API_form "fixed"
-# define API_type png_fixed_point
-# define API_cvt(x) ((double)(x)/PNG_FP_1)
-# endif
-
- API_type rX, gX, bX;
- API_type rY, gY, bY;
- API_type rZ, gZ, bZ;
-
- if ((API_function(pp, pi, &rX, &rY, &rZ, &gX, &gY, &gZ, &bX, &bY, &bZ)
- & PNG_INFO_cHRM) != 0)
- {
- double maxe;
- PNG_CONST char *el;
- color_encoding e, o;
-
- /* Expect libpng to return a normalized result, but the original
- * color space encoding may not be normalized.
- */
- modifier_current_encoding(that->pm, &o);
- normalize_color_encoding(&o);
-
- /* Sanity check the pngvalid code - the coefficients should match
- * the normalized Y values of the encoding unless they were
- * overridden.
- */
- if (data.red_to_set == -1 && data.green_to_set == -1 &&
- (fabs(o.red.Y - data.red_coefficient) > DBL_EPSILON ||
- fabs(o.green.Y - data.green_coefficient) > DBL_EPSILON ||
- fabs(o.blue.Y - data.blue_coefficient) > DBL_EPSILON))
- png_error(pp, "internal pngvalid cHRM coefficient error");
-
- /* Generate a colour space encoding. */
- e.gamma = o.gamma; /* not used */
- e.red.X = API_cvt(rX);
- e.red.Y = API_cvt(rY);
- e.red.Z = API_cvt(rZ);
- e.green.X = API_cvt(gX);
- e.green.Y = API_cvt(gY);
- e.green.Z = API_cvt(gZ);
- e.blue.X = API_cvt(bX);
- e.blue.Y = API_cvt(bY);
- e.blue.Z = API_cvt(bZ);
-
- /* This should match the original one from the png_modifier, within
- * the range permitted by the libpng fixed point representation.
- */
- maxe = 0;
- el = "-"; /* Set to element name with error */
-
-# define CHECK(col,x)\
- {\
- double err = fabs(o.col.x - e.col.x);\
- if (err > maxe)\
- {\
- maxe = err;\
- el = #col "(" #x ")";\
- }\
- }
-
- CHECK(red,X)
- CHECK(red,Y)
- CHECK(red,Z)
- CHECK(green,X)
- CHECK(green,Y)
- CHECK(green,Z)
- CHECK(blue,X)
- CHECK(blue,Y)
- CHECK(blue,Z)
-
- /* Here in both fixed and floating cases to check the values read
- * from the cHRm chunk. PNG uses fixed point in the cHRM chunk, so
- * we can't expect better than +/-.5E-5 on the result, allow 1E-5.
- */
- if (maxe >= 1E-5)
- {
- size_t pos = 0;
- char buffer[256];
-
- pos = safecat(buffer, sizeof buffer, pos, API_form);
- pos = safecat(buffer, sizeof buffer, pos, " cHRM ");
- pos = safecat(buffer, sizeof buffer, pos, el);
- pos = safecat(buffer, sizeof buffer, pos, " error: ");
- pos = safecatd(buffer, sizeof buffer, pos, maxe, 7);
- pos = safecat(buffer, sizeof buffer, pos, " ");
- /* Print the color space without the gamma value: */
- pos = safecat_color_encoding(buffer, sizeof buffer, pos, &o, 0);
- pos = safecat(buffer, sizeof buffer, pos, " -> ");
- pos = safecat_color_encoding(buffer, sizeof buffer, pos, &e, 0);
-
- png_error(pp, buffer);
- }
- }
- }
-# endif /* READ_cHRM */
-
- this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_rgb_to_gray_mod(PNG_CONST image_transform *this,
- image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
-{
- if ((that->colour_type & PNG_COLOR_MASK_COLOR) != 0)
- {
- double gray, err;
-
- if (that->colour_type == PNG_COLOR_TYPE_PALETTE)
- image_pixel_convert_PLTE(that);
-
- /* Image now has RGB channels... */
- {
- PNG_CONST png_modifier *pm = display->pm;
- PNG_CONST unsigned int sample_depth = that->sample_depth;
- int isgray;
- double r, g, b;
- double rlo, rhi, glo, ghi, blo, bhi, graylo, grayhi;
-
- /* Do this using interval arithmetic, otherwise it is too difficult to
- * handle the errors correctly.
- *
- * To handle the gamma correction work out the upper and lower bounds
- * of the digitized value. Assume rounding here - normally the values
- * will be identical after this operation if there is only one
- * transform, feel free to delete the png_error checks on this below in
- * the future (this is just me trying to ensure it works!)
- */
- r = rlo = rhi = that->redf;
- rlo -= that->rede;
- rlo = digitize(pm, rlo, sample_depth, 1/*round*/);
- rhi += that->rede;
- rhi = digitize(pm, rhi, sample_depth, 1/*round*/);
-
- g = glo = ghi = that->greenf;
- glo -= that->greene;
- glo = digitize(pm, glo, sample_depth, 1/*round*/);
- ghi += that->greene;
- ghi = digitize(pm, ghi, sample_depth, 1/*round*/);
-
- b = blo = bhi = that->bluef;
- blo -= that->bluee;
- blo = digitize(pm, blo, sample_depth, 1/*round*/);
- bhi += that->greene;
- bhi = digitize(pm, bhi, sample_depth, 1/*round*/);
-
- isgray = r==g && g==b;
-
- if (data.gamma != 1)
- {
- PNG_CONST double power = 1/data.gamma;
- PNG_CONST double abse = abserr(pm, sample_depth, sample_depth);
-
- /* 'abse' is the absolute error permitted in linear calculations. It
- * is used here to capture the error permitted in the handling
- * (undoing) of the gamma encoding. Once again digitization occurs
- * to handle the upper and lower bounds of the values. This is
- * where the real errors are introduced.
- */
- r = pow(r, power);
- rlo = digitize(pm, pow(rlo, power)-abse, sample_depth, 1);
- rhi = digitize(pm, pow(rhi, power)+abse, sample_depth, 1);
-
- g = pow(g, power);
- glo = digitize(pm, pow(glo, power)-abse, sample_depth, 1);
- ghi = digitize(pm, pow(ghi, power)+abse, sample_depth, 1);
-
- b = pow(b, power);
- blo = digitize(pm, pow(blo, power)-abse, sample_depth, 1);
- bhi = digitize(pm, pow(bhi, power)+abse, sample_depth, 1);
- }
-
- /* Now calculate the actual gray values. Although the error in the
- * coefficients depends on whether they were specified on the command
- * line (in which case truncation to 15 bits happened) or not (rounding
- * was used) the maxium error in an individual coefficient is always
- * 1/32768, because even in the rounding case the requirement that
- * coefficients add up to 32768 can cause a larger rounding error.
- *
- * The only time when rounding doesn't occur in 1.5.5 and later is when
- * the non-gamma code path is used for less than 16 bit data.
- */
- gray = r * data.red_coefficient + g * data.green_coefficient +
- b * data.blue_coefficient;
-
- {
- PNG_CONST int do_round = data.gamma != 1 || sample_depth == 16;
- PNG_CONST double ce = 1. / 32768;
-
- graylo = digitize(pm, rlo * (data.red_coefficient-ce) +
- glo * (data.green_coefficient-ce) +
- blo * (data.blue_coefficient-ce), sample_depth, do_round);
- if (graylo <= 0)
- graylo = 0;
-
- grayhi = digitize(pm, rhi * (data.red_coefficient+ce) +
- ghi * (data.green_coefficient+ce) +
- bhi * (data.blue_coefficient+ce), sample_depth, do_round);
- if (grayhi >= 1)
- grayhi = 1;
- }
-
- /* And invert the gamma. */
- if (data.gamma != 1)
- {
- PNG_CONST double power = data.gamma;
-
- gray = pow(gray, power);
- graylo = digitize(pm, pow(graylo, power), sample_depth, 1);
- grayhi = digitize(pm, pow(grayhi, power), sample_depth, 1);
- }
-
- /* Now the error can be calculated.
- *
- * If r==g==b because there is no overall gamma correction libpng
- * currently preserves the original value.
- */
- if (isgray)
- err = (that->rede + that->greene + that->bluee)/3;
-
- else
- {
- err = fabs(grayhi-gray);
- if (fabs(gray - graylo) > err)
- err = fabs(graylo-gray);
-
- /* Check that this worked: */
- if (err > display->pm->limit)
- {
- size_t pos = 0;
- char buffer[128];
-
- pos = safecat(buffer, sizeof buffer, pos, "rgb_to_gray error ");
- pos = safecatd(buffer, sizeof buffer, pos, err, 6);
- pos = safecat(buffer, sizeof buffer, pos, " exceeds limit ");
- pos = safecatd(buffer, sizeof buffer, pos,
- display->pm->limit, 6);
- png_error(pp, buffer);
- }
- }
- }
-
- that->bluef = that->greenf = that->redf = gray;
- that->bluee = that->greene = that->rede = err;
-
- /* The sBIT is the minium of the three colour channel sBITs. */
- if (that->red_sBIT > that->green_sBIT)
- that->red_sBIT = that->green_sBIT;
- if (that->red_sBIT > that->blue_sBIT)
- that->red_sBIT = that->blue_sBIT;
- that->blue_sBIT = that->green_sBIT = that->red_sBIT;
-
- /* And remove the colour bit in the type: */
- if (that->colour_type == PNG_COLOR_TYPE_RGB)
- that->colour_type = PNG_COLOR_TYPE_GRAY;
- else if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA)
- that->colour_type = PNG_COLOR_TYPE_GRAY_ALPHA;
- }
-
- this->next->mod(this->next, that, pp, display);
-}
-
-static int
-image_transform_png_set_rgb_to_gray_add(image_transform *this,
- PNG_CONST image_transform **that, png_byte colour_type, png_byte bit_depth)
-{
- UNUSED(bit_depth)
-
- this->next = *that;
- *that = this;
-
- return (colour_type & PNG_COLOR_MASK_COLOR) != 0;
-}
-
-#undef data
-IT(rgb_to_gray);
-#undef PT
-#define PT ITSTRUCT(rgb_to_gray)
-#undef image_transform_ini
-#define image_transform_ini image_transform_default_ini
-#endif /* PNG_READ_RGB_TO_GRAY_SUPPORTED */
-
-#ifdef PNG_READ_BACKGROUND_SUPPORTED
-/* png_set_background(png_structp, png_const_color_16p background_color,
- * int background_gamma_code, int need_expand, double background_gamma)
- * png_set_background_fixed(png_structp, png_const_color_16p background_color,
- * int background_gamma_code, int need_expand,
- * png_fixed_point background_gamma)
- *
- * As with rgb_to_gray this ignores the gamma (at present.)
-*/
-#define data ITDATA(background)
-static image_pixel data;
-
-static void
-image_transform_png_set_background_set(PNG_CONST image_transform *this,
- transform_display *that, png_structp pp, png_infop pi)
-{
- png_byte colour_type, bit_depth;
- png_byte random_bytes[8]; /* 8 bytes - 64 bits - the biggest pixel */
- png_color_16 back;
-
- /* We need a background colour, because we don't know exactly what transforms
- * have been set we have to supply the colour in the original file format and
- * so we need to know what that is! The background colour is stored in the
- * transform_display.
- */
- RANDOMIZE(random_bytes);
-
- /* Read the random value, for colour type 3 the background colour is actually
- * expressed as a 24bit rgb, not an index.
- */
- colour_type = that->this.colour_type;
- if (colour_type == 3)
- {
- colour_type = PNG_COLOR_TYPE_RGB;
- bit_depth = 8;
- }
-
- else
- bit_depth = that->this.bit_depth;
-
- image_pixel_init(&data, random_bytes, colour_type,
- bit_depth, 0/*x*/, 0/*unused: palette*/);
-
- /* Extract the background colour from this image_pixel, but make sure the
- * unused fields of 'back' are garbage.
- */
- RANDOMIZE(back);
-
- if (colour_type & PNG_COLOR_MASK_COLOR)
- {
- back.red = (png_uint_16)data.red;
- back.green = (png_uint_16)data.green;
- back.blue = (png_uint_16)data.blue;
- }
-
- else
- back.gray = (png_uint_16)data.red;
-
-# ifdef PNG_FLOATING_POINT_SUPPORTED
- png_set_background(pp, &back, PNG_BACKGROUND_GAMMA_FILE, 1/*need expand*/,
- 0);
-# else
- png_set_background_fixed(pp, &back, PNG_BACKGROUND_GAMMA_FILE,
- 1/*need expand*/, 0);
-# endif
-
- this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_background_mod(PNG_CONST image_transform *this,
- image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
-{
- /* Check for tRNS first: */
- if (that->have_tRNS && that->colour_type != PNG_COLOR_TYPE_PALETTE)
- image_pixel_add_alpha(that, &display->this);
-
- /* This is only necessary if the alpha value is less than 1. */
- if (that->alphaf < 1)
- {
- /* Now we do the background calculation without any gamma correction. */
- if (that->alphaf <= 0)
- {
- that->redf = data.redf;
- that->greenf = data.greenf;
- that->bluef = data.bluef;
-
- that->rede = data.rede;
- that->greene = data.greene;
- that->bluee = data.bluee;
-
- that->red_sBIT= data.red_sBIT;
- that->green_sBIT= data.green_sBIT;
- that->blue_sBIT= data.blue_sBIT;
- }
-
- else /* 0 < alpha < 1 */
- {
- double alf = 1 - that->alphaf;
-
- that->redf = that->redf * that->alphaf + data.redf * alf;
- that->rede = that->rede * that->alphaf + data.rede * alf +
- DBL_EPSILON;
- that->greenf = that->greenf * that->alphaf + data.greenf * alf;
- that->greene = that->greene * that->alphaf + data.greene * alf +
- DBL_EPSILON;
- that->bluef = that->bluef * that->alphaf + data.bluef * alf;
- that->bluee = that->bluee * that->alphaf + data.bluee * alf +
- DBL_EPSILON;
- }
-
- /* Remove the alpha type and set the alpha (not in that order.) */
- that->alphaf = 1;
- that->alphae = 0;
-
- if (that->colour_type == PNG_COLOR_TYPE_RGB_ALPHA)
- that->colour_type = PNG_COLOR_TYPE_RGB;
- else if (that->colour_type == PNG_COLOR_TYPE_GRAY_ALPHA)
- that->colour_type = PNG_COLOR_TYPE_GRAY;
- /* PNG_COLOR_TYPE_PALETTE is not changed */
- }
-
- this->next->mod(this->next, that, pp, display);
-}
-
-#define image_transform_png_set_background_add image_transform_default_add
-
-#undef data
-IT(background);
-#undef PT
-#define PT ITSTRUCT(background)
-#endif /* PNG_READ_BACKGROUND_SUPPORTED */
-
-/* This may just be 'end' if all the transforms are disabled! */
-static image_transform *PNG_CONST image_transform_first = &PT;
-
-static void
-transform_enable(PNG_CONST char *name)
-{
- /* Everything starts out enabled, so if we see an 'enable' disabled
- * everything else the first time round.
- */
- static int all_disabled = 0;
- int found_it = 0;
- image_transform *list = image_transform_first;
-
- while (list != &image_transform_end)
- {
- if (strcmp(list->name, name) == 0)
- {
- list->enable = 1;
- found_it = 1;
- }
- else if (!all_disabled)
- list->enable = 0;
-
- list = list->list;
- }
-
- all_disabled = 1;
-
- if (!found_it)
- {
- fprintf(stderr, "pngvalid: --transform-enable=%s: unknown transform\n",
- name);
- exit(1);
- }
-}
-
-static void
-transform_disable(PNG_CONST char *name)
-{
- image_transform *list = image_transform_first;
-
- while (list != &image_transform_end)
- {
- if (strcmp(list->name, name) == 0)
- {
- list->enable = 0;
- return;
- }
-
- list = list->list;
- }
-
- fprintf(stderr, "pngvalid: --transform-disable=%s: unknown transform\n",
- name);
- exit(1);
-}
-
-static void
-image_transform_reset_count(void)
-{
- image_transform *next = image_transform_first;
- int count = 0;
-
- while (next != &image_transform_end)
- {
- next->local_use = 0;
- next->next = 0;
- next = next->list;
- ++count;
- }
-
- /* This can only happen if we every have more than 32 transforms (excluding
- * the end) in the list.
- */
- if (count > 32) abort();
-}
-
-static int
-image_transform_test_counter(png_uint_32 counter, unsigned int max)
-{
- /* Test the list to see if there is any point contining, given a current
- * counter and a 'max' value.
- */
- image_transform *next = image_transform_first;
-
- while (next != &image_transform_end)
- {
- /* For max 0 or 1 continue until the counter overflows: */
- counter >>= 1;
-
- /* Continue if any entry hasn't reacked the max. */
- if (max > 1 && next->local_use < max)
- return 1;
- next = next->list;
- }
-
- return max <= 1 && counter == 0;
-}
-
-static png_uint_32
-image_transform_add(PNG_CONST image_transform **this, unsigned int max,
- png_uint_32 counter, char *name, size_t sizeof_name, size_t *pos,
- png_byte colour_type, png_byte bit_depth)
-{
- for (;;) /* until we manage to add something */
- {
- png_uint_32 mask;
- image_transform *list;
-
- /* Find the next counter value, if the counter is zero this is the start
- * of the list. This routine always returns the current counter (not the
- * next) so it returns 0 at the end and expects 0 at the beginning.
- */
- if (counter == 0) /* first time */
- {
- image_transform_reset_count();
- if (max <= 1)
- counter = 1;
- else
- counter = random_32();
- }
- else /* advance the counter */
- {
- switch (max)
- {
- case 0: ++counter; break;
- case 1: counter <<= 1; break;
- default: counter = random_32(); break;
- }
- }
-
- /* Now add all these items, if possible */
- *this = &image_transform_end;
- list = image_transform_first;
- mask = 1;
-
- /* Go through the whole list adding anything that the counter selects: */
- while (list != &image_transform_end)
- {
- if ((counter & mask) != 0 && list->enable &&
- (max == 0 || list->local_use < max))
- {
- /* Candidate to add: */
- if (list->add(list, this, colour_type, bit_depth) || max == 0)
- {
- /* Added, so add to the name too. */
- *pos = safecat(name, sizeof_name, *pos, " +");
- *pos = safecat(name, sizeof_name, *pos, list->name);
- }
-
- else
- {
- /* Not useful and max>0, so remove it from *this: */
- *this = list->next;
- list->next = 0;
-
- /* And, since we know it isn't useful, stop it being added again
- * in this run:
- */
- list->local_use = max;
- }
- }
-
- mask <<= 1;
- list = list->list;
- }
-
- /* Now if anything was added we have something to do. */
- if (*this != &image_transform_end)
- return counter;
-
- /* Nothing added, but was there anything in there to add? */
- if (!image_transform_test_counter(counter, max))
- return 0;
- }
-}
-
-#ifdef THIS_IS_THE_PROFORMA
-static void
-image_transform_png_set_@_set(PNG_CONST image_transform *this,
- transform_display *that, png_structp pp, png_infop pi)
-{
- png_set_@(pp);
- this->next->set(this->next, that, pp, pi);
-}
-
-static void
-image_transform_png_set_@_mod(PNG_CONST image_transform *this,
- image_pixel *that, png_structp pp, PNG_CONST transform_display *display)
-{
- this->next->mod(this->next, that, pp, display);
-}
-
-static int
-image_transform_png_set_@_add(image_transform *this,
- PNG_CONST image_transform **that, char *name, size_t sizeof_name,
- size_t *pos, png_byte colour_type, png_byte bit_depth)
-{
- this->next = *that;
- *that = this;
-
- *pos = safecat(name, sizeof_name, *pos, " +@");
-
- return 1;
-}
-
-IT(@);
-#endif
-
-/* png_set_quantize(png_structp, png_colorp palette, int num_palette,
- * int maximum_colors, png_const_uint_16p histogram, int full_quantize)
- *
- * Very difficult to validate this!
- */
-/*NOTE: TBD NYI */
-
-/* The data layout transforms are handled by swapping our own channel data,
- * necessarily these need to happen at the end of the transform list because the
- * semantic of the channels changes after these are executed. Some of these,
- * like set_shift and set_packing, can't be done at present because they change
- * the layout of the data at the sub-sample level so sample() won't get the
- * right answer.
- */
-/* png_set_invert_alpha */
-/*NOTE: TBD NYI */
-
-/* png_set_bgr */
-/*NOTE: TBD NYI */
-
-/* png_set_swap_alpha */
-/*NOTE: TBD NYI */
-
-/* png_set_swap */
-/*NOTE: TBD NYI */
-
-/* png_set_filler, (png_structp png_ptr, png_uint_32 filler, int flags)); */
-/*NOTE: TBD NYI */
-
-/* png_set_add_alpha, (png_structp png_ptr, png_uint_32 filler, int flags)); */
-/*NOTE: TBD NYI */
-
-/* png_set_packing */
-/*NOTE: TBD NYI */
-
-/* png_set_packswap */
-/*NOTE: TBD NYI */
-
-/* png_set_invert_mono */
-/*NOTE: TBD NYI */
-
-/* png_set_shift(png_structp, png_const_color_8p true_bits) */
-/*NOTE: TBD NYI */
-
-static void
-perform_transform_test(png_modifier *pm)
-{
- png_byte colour_type = 0;
- png_byte bit_depth = 0;
- int palette_number = 0;
-
- while (next_format(&colour_type, &bit_depth, &palette_number))
- {
- png_uint_32 counter = 0;
- size_t base_pos;
- char name[64];
-
- base_pos = safecat(name, sizeof name, 0, "transform:");
-
- for (;;)
- {
- size_t pos = base_pos;
- PNG_CONST image_transform *list = 0;
-
- /* 'max' is currently hardwired to '1'; this should be settable on the
- * command line.
- */
- counter = image_transform_add(&list, 1/*max*/, counter,
- name, sizeof name, &pos, colour_type, bit_depth);
-
- if (counter == 0)
- break;
-
- /* The command line can change this to checking interlaced images. */
- do
- {
- pm->repeat = 0;
- transform_test(pm, FILEID(colour_type, bit_depth, palette_number,
- pm->interlace_type, 0, 0, 0), list, name);
-
- if (fail(pm))
- return;
- }
- while (pm->repeat);
- }
- }
-}
-#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
-
-/********************************* GAMMA TESTS ********************************/
-#ifdef PNG_READ_GAMMA_SUPPORTED
-/* Reader callbacks and implementations, where they differ from the standard
- * ones.
- */
-typedef struct gamma_display
-{
- standard_display this;
-
- /* Parameters */
- png_modifier* pm;
- double file_gamma;
- double screen_gamma;
- double background_gamma;
- png_byte sbit;
- int threshold_test;
- int use_input_precision;
- int scale16;
- int expand16;
- int do_background;
- png_color_16 background_color;
-
- /* Local variables */
- double maxerrout;
- double maxerrpc;
- double maxerrabs;
-} gamma_display;
-
-#define ALPHA_MODE_OFFSET 4
-
-static void
-gamma_display_init(gamma_display *dp, png_modifier *pm, png_uint_32 id,
- double file_gamma, double screen_gamma, png_byte sbit, int threshold_test,
- int use_input_precision, int scale16, int expand16,
- int do_background, PNG_CONST png_color_16 *pointer_to_the_background_color,
- double background_gamma)
-{
- /* Standard fields */
- standard_display_init(&dp->this, &pm->this, id, 0/*do_interlace*/,
- pm->use_update_info);
-
- /* Parameter fields */
- dp->pm = pm;
- dp->file_gamma = file_gamma;
- dp->screen_gamma = screen_gamma;
- dp->background_gamma = background_gamma;
- dp->sbit = sbit;
- dp->threshold_test = threshold_test;
- dp->use_input_precision = use_input_precision;
- dp->scale16 = scale16;
- dp->expand16 = expand16;
- dp->do_background = do_background;
- if (do_background && pointer_to_the_background_color != 0)
- dp->background_color = *pointer_to_the_background_color;
- else
- memset(&dp->background_color, 0, sizeof dp->background_color);
-
- /* Local variable fields */
- dp->maxerrout = dp->maxerrpc = dp->maxerrabs = 0;
-}
-
-static void
-gamma_info_imp(gamma_display *dp, png_structp pp, png_infop pi)
-{
- /* Reuse the standard stuff as appropriate. */
- standard_info_part1(&dp->this, pp, pi);
-
- /* If requested strip 16 to 8 bits - this is handled automagically below
- * because the output bit depth is read from the library. Note that there
- * are interactions with sBIT but, internally, libpng makes sbit at most
- * PNG_MAX_GAMMA_8 when doing the following.
- */
- if (dp->scale16)
-# ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
- png_set_scale_16(pp);
-# else
- /* The following works both in 1.5.4 and earlier versions: */
-# ifdef PNG_READ_16_TO_8_SUPPORTED
- png_set_strip_16(pp);
-# else
- png_error(pp, "scale16 (16 to 8 bit conversion) not supported");
-# endif
-# endif
-
- if (dp->expand16)
-# ifdef PNG_READ_EXPAND_16_SUPPORTED
- png_set_expand_16(pp);
-# else
- png_error(pp, "expand16 (8 to 16 bit conversion) not supported");
-# endif
-
- if (dp->do_background >= ALPHA_MODE_OFFSET)
- {
-# ifdef PNG_READ_ALPHA_MODE_SUPPORTED
- {
- /* This tests the alpha mode handling, if supported. */
- int mode = dp->do_background - ALPHA_MODE_OFFSET;
-
- /* The gamma value is the output gamma, and is in the standard,
- * non-inverted, represenation. It provides a default for the PNG file
- * gamma, but since the file has a gAMA chunk this does not matter.
- */
- PNG_CONST double sg = dp->screen_gamma;
-# ifndef PNG_FLOATING_POINT_SUPPORTED
- PNG_CONST png_fixed_point g = fix(sg);
-# endif
-
-# ifdef PNG_FLOATING_POINT_SUPPORTED
- png_set_alpha_mode(pp, mode, sg);
-# else
- png_set_alpha_mode_fixed(pp, mode, g);
-# endif
-
- /* However, for the standard Porter-Duff algorithm the output defaults
- * to be linear, so if the test requires non-linear output it must be
- * corrected here.
- */
- if (mode == PNG_ALPHA_STANDARD && sg != 1)
- {
-# ifdef PNG_FLOATING_POINT_SUPPORTED
- png_set_gamma(pp, sg, dp->file_gamma);
-# else
- png_fixed_point f = fix(dp->file_gamma);
- png_set_gamma_fixed(pp, g, f);
-# endif
- }
- }
-# else
- png_error(pp, "alpha mode handling not supported");
-# endif
- }
-
- else
- {
- /* Set up gamma processing. */
-# ifdef PNG_FLOATING_POINT_SUPPORTED
- png_set_gamma(pp, dp->screen_gamma, dp->file_gamma);
-# else
- {
- png_fixed_point s = fix(dp->screen_gamma);
- png_fixed_point f = fix(dp->file_gamma);
- png_set_gamma_fixed(pp, s, f);
- }
-# endif
-
- if (dp->do_background)
- {
-# ifdef PNG_READ_BACKGROUND_SUPPORTED
- /* NOTE: this assumes the caller provided the correct background gamma!
- */
- PNG_CONST double bg = dp->background_gamma;
-# ifndef PNG_FLOATING_POINT_SUPPORTED
- PNG_CONST png_fixed_point g = fix(bg);
-# endif
-
-# ifdef PNG_FLOATING_POINT_SUPPORTED
- png_set_background(pp, &dp->background_color, dp->do_background,
- 0/*need_expand*/, bg);
-# else
- png_set_background_fixed(pp, &dp->background_color,
- dp->do_background, 0/*need_expand*/, g);
-# endif
-# else
- png_error(pp, "png_set_background not supported");
-# endif
- }
- }
-
- {
- int i = dp->this.use_update_info;
- /* Always do one call, even if use_update_info is 0. */
- do
- png_read_update_info(pp, pi);
- while (--i > 0);
- }
-
- /* Now we may get a different cbRow: */
- standard_info_part2(&dp->this, pp, pi, 1 /*images*/);
-}
-
-static void
-gamma_info(png_structp pp, png_infop pi)
-{
- gamma_info_imp(voidcast(gamma_display*, png_get_progressive_ptr(pp)), pp,
- pi);
-}
-
-/* Validate a single component value - the routine gets the input and output
- * sample values as unscaled PNG component values along with a cache of all the
- * information required to validate the values.
- */
-typedef struct validate_info
-{
- png_structp pp;
- gamma_display *dp;
- png_byte sbit;
- int use_input_precision;
- int do_background;
- int scale16;
- unsigned int sbit_max;
- unsigned int isbit_shift;
- unsigned int outmax;
-
- double gamma_correction; /* Overall correction required. */
- double file_inverse; /* Inverse of file gamma. */
- double screen_gamma;
- double screen_inverse; /* Inverse of screen gamma. */
-
- double background_red; /* Linear background value, red or gray. */
- double background_green;
- double background_blue;
-
- double maxabs;
- double maxpc;
- double maxcalc;
- double maxout;
- double maxout_total; /* Total including quantization error */
- double outlog;
- int outquant;
-}
-validate_info;
-
-static void
-init_validate_info(validate_info *vi, gamma_display *dp, png_struct *pp,
- int in_depth, int out_depth)
-{
- PNG_CONST unsigned int outmax = (1U<<out_depth)-1;
-
- vi->pp = pp;
- vi->dp = dp;
-
- if (dp->sbit > 0 && dp->sbit < in_depth)
- {
- vi->sbit = dp->sbit;
- vi->isbit_shift = in_depth - dp->sbit;
- }
-
- else
- {
- vi->sbit = (png_byte)in_depth;
- vi->isbit_shift = 0;
- }
-
- vi->sbit_max = (1U << vi->sbit)-1;
-
- /* This mimics the libpng threshold test, '0' is used to prevent gamma
- * correction in the validation test.
- */
- vi->screen_gamma = dp->screen_gamma;
- if (fabs(vi->screen_gamma-1) < PNG_GAMMA_THRESHOLD)
- vi->screen_gamma = vi->screen_inverse = 0;
- else
- vi->screen_inverse = 1/vi->screen_gamma;
-
- vi->use_input_precision = dp->use_input_precision;
- vi->outmax = outmax;
- vi->maxabs = abserr(dp->pm, in_depth, out_depth);
- vi->maxpc = pcerr(dp->pm, in_depth, out_depth);
- vi->maxcalc = calcerr(dp->pm, in_depth, out_depth);
- vi->maxout = outerr(dp->pm, in_depth, out_depth);
- vi->outquant = output_quantization_factor(dp->pm, in_depth, out_depth);
- vi->maxout_total = vi->maxout + vi->outquant * .5;
- vi->outlog = outlog(dp->pm, in_depth, out_depth);
-
- if ((dp->this.colour_type & PNG_COLOR_MASK_ALPHA) != 0 ||
- (dp->this.colour_type == 3 && dp->this.is_transparent))
- {
- vi->do_background = dp->do_background;
-
- if (vi->do_background != 0)
- {
- PNG_CONST double bg_inverse = 1/dp->background_gamma;
- double r, g, b;
-
- /* Caller must at least put the gray value into the red channel */
- r = dp->background_color.red; r /= outmax;
- g = dp->background_color.green; g /= outmax;
- b = dp->background_color.blue; b /= outmax;
-
-# if 0
- /* libpng doesn't do this optimization, if we do pngvalid will fail.
- */
- if (fabs(bg_inverse-1) >= PNG_GAMMA_THRESHOLD)
-# endif
- {
- r = pow(r, bg_inverse);
- g = pow(g, bg_inverse);
- b = pow(b, bg_inverse);
- }
-
- vi->background_red = r;
- vi->background_green = g;
- vi->background_blue = b;
- }
- }
- else
- vi->do_background = 0;
-
- if (vi->do_background == 0)
- vi->background_red = vi->background_green = vi->background_blue = 0;
-
- vi->gamma_correction = 1/(dp->file_gamma*dp->screen_gamma);
- if (fabs(vi->gamma_correction-1) < PNG_GAMMA_THRESHOLD)
- vi->gamma_correction = 0;
-
- vi->file_inverse = 1/dp->file_gamma;
- if (fabs(vi->file_inverse-1) < PNG_GAMMA_THRESHOLD)
- vi->file_inverse = 0;
-
- vi->scale16 = dp->scale16;
-}
-
-/* This function handles composition of a single non-alpha component. The
- * argument is the input sample value, in the range 0..1, and the alpha value.
- * The result is the composed, linear, input sample. If alpha is less than zero
- * this is the alpha component and the function should not be called!
- */
-static double
-gamma_component_compose(int do_background, double input_sample, double alpha,
- double background, int *compose)
-{
- switch (do_background)
- {
- case PNG_BACKGROUND_GAMMA_SCREEN:
- case PNG_BACKGROUND_GAMMA_FILE:
- case PNG_BACKGROUND_GAMMA_UNIQUE:
- /* Standard PNG background processing. */
- if (alpha < 1)
- {
- if (alpha > 0)
- {
- input_sample = input_sample * alpha + background * (1-alpha);
- if (compose != NULL)
- *compose = 1;
- }
-
- else
- input_sample = background;
- }
- break;
-
-#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
- case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD:
- case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN:
- /* The components are premultiplied in either case and the output is
- * gamma encoded (to get standard Porter-Duff we expect the output
- * gamma to be set to 1.0!)
- */
- case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED:
- /* The optimization is that the partial-alpha entries are linear
- * while the opaque pixels are gamma encoded, but this only affects the
- * output encoding.
- */
- if (alpha < 1)
- {
- if (alpha > 0)
- {
- input_sample *= alpha;
- if (compose != NULL)
- *compose = 1;
- }
-
- else
- input_sample = 0;
- }
- break;
-#endif
-
- default:
- /* Standard cases where no compositing is done (so the component
- * value is already correct.)
- */
- break;
- }
-
- return input_sample;
-}
-
-/* This API returns the encoded *input* component, in the range 0..1 */
-static double
-gamma_component_validate(PNG_CONST char *name, PNG_CONST validate_info *vi,
- PNG_CONST unsigned int id, PNG_CONST unsigned int od,
- PNG_CONST double alpha /* <0 for the alpha channel itself */,
- PNG_CONST double background /* component background value */)
-{
- PNG_CONST unsigned int isbit = id >> vi->isbit_shift;
- PNG_CONST unsigned int sbit_max = vi->sbit_max;
- PNG_CONST unsigned int outmax = vi->outmax;
- PNG_CONST int do_background = vi->do_background;
-
- double i;
-
- /* First check on the 'perfect' result obtained from the digitized input
- * value, id, and compare this against the actual digitized result, 'od'.
- * 'i' is the input result in the range 0..1:
- */
- i = isbit; i /= sbit_max;
-
- /* Check for the fast route: if we don't do any background composition or if
- * this is the alpha channel ('alpha' < 0) or if the pixel is opaque then
- * just use the gamma_correction field to correct to the final output gamma.
- */
- if (alpha == 1 /* opaque pixel component */ || !do_background
-#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
- || do_background == ALPHA_MODE_OFFSET + PNG_ALPHA_PNG
-#endif
- || (alpha < 0 /* alpha channel */
-#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
- && do_background != ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN
-#endif
- ))
- {
- /* Then get the gamma corrected version of 'i' and compare to 'od', any
- * error less than .5 is insignificant - just quantization of the output
- * value to the nearest digital value (nevertheless the error is still
- * recorded - it's interesting ;-)
- */
- double encoded_sample = i;
- double encoded_error;
-
- /* alpha less than 0 indicates the alpha channel, which is always linear
- */
- if (alpha >= 0 && vi->gamma_correction > 0)
- encoded_sample = pow(encoded_sample, vi->gamma_correction);
- encoded_sample *= outmax;
-
- encoded_error = fabs(od-encoded_sample);
-
- if (encoded_error > vi->dp->maxerrout)
- vi->dp->maxerrout = encoded_error;
-
- if (encoded_error < vi->maxout_total && encoded_error < vi->outlog)
- return i;
- }
-
- /* The slow route - attempt to do linear calculations. */
- /* There may be an error, or background processing is required, so calculate
- * the actual sample values - unencoded light intensity values. Note that in
- * practice these are not completely unencoded because they include a
- * 'viewing correction' to decrease or (normally) increase the perceptual
- * contrast of the image. There's nothing we can do about this - we don't
- * know what it is - so assume the unencoded value is perceptually linear.
- */
- {
- double input_sample = i; /* In range 0..1 */
- double output, error, encoded_sample, encoded_error;
- double es_lo, es_hi;
- int compose = 0; /* Set to one if composition done */
- int output_is_encoded; /* Set if encoded to screen gamma */
- int log_max_error = 1; /* Check maximum error values */
- png_const_charp pass = 0; /* Reason test passes (or 0 for fail) */
-
- /* Convert to linear light (with the above caveat.) The alpha channel is
- * already linear.
- */
- if (alpha >= 0)
- {
- int tcompose;
-
- if (vi->file_inverse > 0)
- input_sample = pow(input_sample, vi->file_inverse);
-
- /* Handle the compose processing: */
- tcompose = 0;
- input_sample = gamma_component_compose(do_background, input_sample,
- alpha, background, &tcompose);
-
- if (tcompose)
- compose = 1;
- }
-
- /* And similarly for the output value, but we need to check the background
- * handling to linearize it correctly.
- */
- output = od;
- output /= outmax;
-
- output_is_encoded = vi->screen_gamma > 0;
-
- if (alpha < 0) /* The alpha channel */
- {
-#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
- if (do_background != ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN)
-#endif
- {
- /* In all other cases the output alpha channel is linear already,
- * don't log errors here, they are much larger in linear data.
- */
- output_is_encoded = 0;
- log_max_error = 0;
- }
- }
-
-#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
- else /* A component */
- {
- if (do_background == ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED &&
- alpha < 1) /* the optimized case - linear output */
- {
- if (alpha > 0) log_max_error = 0;
- output_is_encoded = 0;
- }
- }
-#endif
-
- if (output_is_encoded)
- output = pow(output, vi->screen_gamma);
-
- /* Calculate (or recalculate) the encoded_sample value and repeat the
- * check above (unnecessary if we took the fast route, but harmless.)
- */
- encoded_sample = input_sample;
- if (output_is_encoded)
- encoded_sample = pow(encoded_sample, vi->screen_inverse);
- encoded_sample *= outmax;
-
- encoded_error = fabs(od-encoded_sample);
-
- /* Don't log errors in the alpha channel, or the 'optimized' case,
- * neither are significant to the overall perception.
- */
- if (log_max_error && encoded_error > vi->dp->maxerrout)
- vi->dp->maxerrout = encoded_error;
-
- if (encoded_error < vi->maxout_total)
- {
- if (encoded_error < vi->outlog)
- return i;
-
- /* Test passed but error is bigger than the log limit, record why the
- * test passed:
- */
- pass = "less than maxout:\n";
- }
-
- /* i: the original input value in the range 0..1
- *
- * pngvalid calculations:
- * input_sample: linear result; i linearized and composed, range 0..1
- * encoded_sample: encoded result; input_sample scaled to ouput bit depth
- *
- * libpng calculations:
- * output: linear result; od scaled to 0..1 and linearized
- * od: encoded result from libpng
- */
-
- /* Now we have the numbers for real errors, both absolute values as as a
- * percentage of the correct value (output):
- */
- error = fabs(input_sample-output);
-
- if (log_max_error && error > vi->dp->maxerrabs)
- vi->dp->maxerrabs = error;
-
- /* The following is an attempt to ignore the tendency of quantization to
- * dominate the percentage errors for lower result values:
- */
- if (log_max_error && input_sample > .5)
- {
- double percentage_error = error/input_sample;
- if (percentage_error > vi->dp->maxerrpc)
- vi->dp->maxerrpc = percentage_error;
- }
-
- /* Now calculate the digitization limits for 'encoded_sample' using the
- * 'max' values. Note that maxout is in the encoded space but maxpc and
- * maxabs are in linear light space.
- *
- * First find the maximum error in linear light space, range 0..1:
- */
- {
- double tmp = input_sample * vi->maxpc;
- if (tmp < vi->maxabs) tmp = vi->maxabs;
- /* If 'compose' is true the composition was done in linear space using
- * integer arithmetic. This introduces an extra error of +/- 0.5 (at
- * least) in the integer space used. 'maxcalc' records this, taking
- * into account the possibility that even for 16 bit output 8 bit space
- * may have been used.
- */
- if (compose && tmp < vi->maxcalc) tmp = vi->maxcalc;
-
- /* The 'maxout' value refers to the encoded result, to compare with
- * this encode input_sample adjusted by the maximum error (tmp) above.
- */
- es_lo = encoded_sample - vi->maxout;
-
- if (es_lo > 0 && input_sample-tmp > 0)
- {
- double low_value = input_sample-tmp;
- if (output_is_encoded)
- low_value = pow(low_value, vi->screen_inverse);
- low_value *= outmax;
- if (low_value < es_lo) es_lo = low_value;
-
- /* Quantize this appropriately: */
- es_lo = ceil(es_lo / vi->outquant - .5) * vi->outquant;
- }
-
- else
- es_lo = 0;
-
- es_hi = encoded_sample + vi->maxout;
-
- if (es_hi < outmax && input_sample+tmp < 1)
- {
- double high_value = input_sample+tmp;
- if (output_is_encoded)
- high_value = pow(high_value, vi->screen_inverse);
- high_value *= outmax;
- if (high_value > es_hi) es_hi = high_value;
-
- es_hi = floor(es_hi / vi->outquant + .5) * vi->outquant;
- }
-
- else
- es_hi = outmax;
- }
-
- /* The primary test is that the final encoded value returned by the
- * library should be between the two limits (inclusive) that were
- * calculated above.
- */
- if (od >= es_lo && od <= es_hi)
- {
- /* The value passes, but we may need to log the information anyway. */
- if (encoded_error < vi->outlog)
- return i;
-
- if (pass == 0)
- pass = "within digitization limits:\n";
- }
-
- {
- /* There has been an error in processing, or we need to log this
- * value.
- */
- double is_lo, is_hi;
-
- /* pass is set at this point if either of the tests above would have
- * passed. Don't do these additional tests here - just log the
- * original [es_lo..es_hi] values.
- */
- if (pass == 0 && vi->use_input_precision)
- {
- /* Ok, something is wrong - this actually happens in current libpng
- * 16-to-8 processing. Assume that the input value (id, adjusted
- * for sbit) can be anywhere between value-.5 and value+.5 - quite a
- * large range if sbit is low.
- */
- double tmp = (isbit - .5)/sbit_max;
-
- if (tmp <= 0)
- tmp = 0;
-
- else if (alpha >= 0 && vi->file_inverse > 0 && tmp < 1)
- tmp = pow(tmp, vi->file_inverse);
-
- tmp = gamma_component_compose(do_background, tmp, alpha, background,
- NULL);
-
- if (output_is_encoded && tmp > 0 && tmp < 1)
- tmp = pow(tmp, vi->screen_inverse);
-
- is_lo = ceil(outmax * tmp - vi->maxout_total);
-
- if (is_lo < 0)
- is_lo = 0;
-
- tmp = (isbit + .5)/sbit_max;
-
- if (tmp <= 0)
- tmp = 0;
-
- else if (alpha >= 0 && vi->file_inverse > 0 && tmp < 1)
- tmp = pow(tmp, vi->file_inverse);
-
- tmp = gamma_component_compose(do_background, tmp, alpha, background,
- NULL);
-
- if (output_is_encoded && tmp > 0 && tmp < 1)
- tmp = pow(tmp, vi->screen_inverse);
-
- is_hi = floor(outmax * tmp + vi->maxout_total);
-
- if (is_hi > outmax)
- is_hi = outmax;
-
- if (!(od < is_lo || od > is_hi))
- {
- if (encoded_error < vi->outlog)
- return i;
-
- pass = "within input precision limits:\n";
- }
-
- /* One last chance. If this is an alpha channel and the 16to8
- * option has been used and 'inaccurate' scaling is used then the
- * bit reduction is obtained by simply using the top 8 bits of the
- * value.
- *
- * This is only done for older libpng versions when the 'inaccurate'
- * (chop) method of scaling was used.
- */
-# ifndef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
-# if PNG_LIBPNG_VER < 10504
- /* This may be required for other components in the future,
- * but at present the presence of gamma correction effectively
- * prevents the errors in the component scaling (I don't quite
- * understand why, but since it's better this way I care not
- * to ask, JB 20110419.)
- */
- if (pass == 0 && alpha < 0 && vi->scale16 && vi->sbit > 8 &&
- vi->sbit + vi->isbit_shift == 16)
- {
- tmp = ((id >> 8) - .5)/255;
-
- if (tmp > 0)
- {
- is_lo = ceil(outmax * tmp - vi->maxout_total);
- if (is_lo < 0) is_lo = 0;
- }
-
- else
- is_lo = 0;
-
- tmp = ((id >> 8) + .5)/255;
-
- if (tmp < 1)
- {
- is_hi = floor(outmax * tmp + vi->maxout_total);
- if (is_hi > outmax) is_hi = outmax;
- }
-
- else
- is_hi = outmax;
-
- if (!(od < is_lo || od > is_hi))
- {
- if (encoded_error < vi->outlog)
- return i;
-
- pass = "within 8 bit limits:\n";
- }
- }
-# endif
-# endif
- }
- else /* !use_input_precision */
- is_lo = es_lo, is_hi = es_hi;
-
- /* Attempt to output a meaningful error/warning message: the message
- * output depends on the background/composite operation being performed
- * because this changes what parameters were actually used above.
- */
- {
- size_t pos = 0;
- /* Need either 1/255 or 1/65535 precision here; 3 or 6 decimal
- * places. Just use outmax to work out which.
- */
- int precision = (outmax >= 1000 ? 6 : 3);
- int use_input=1, use_background=0, do_compose=0;
- char msg[256];
-
- if (pass != 0)
- pos = safecat(msg, sizeof msg, pos, "\n\t");
-
- /* Set up the various flags, the output_is_encoded flag above
- * is also used below. do_compose is just a double check.
- */
- switch (do_background)
- {
- case PNG_BACKGROUND_GAMMA_SCREEN:
- case PNG_BACKGROUND_GAMMA_FILE:
- case PNG_BACKGROUND_GAMMA_UNIQUE:
- use_background = (alpha >= 0 && alpha < 1);
- /*FALL THROUGH*/
-# ifdef PNG_READ_ALPHA_MODE_SUPPORTED
- case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD:
- case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN:
- case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED:
-# endif /* ALPHA_MODE_SUPPORTED */
- do_compose = (alpha > 0 && alpha < 1);
- use_input = (alpha != 0);
- break;
-
- default:
- break;
- }
-
- /* Check the 'compose' flag */
- if (compose != do_compose)
- png_error(vi->pp, "internal error (compose)");
-
- /* 'name' is the component name */
- pos = safecat(msg, sizeof msg, pos, name);
- pos = safecat(msg, sizeof msg, pos, "(");
- pos = safecatn(msg, sizeof msg, pos, id);
- if (use_input || pass != 0/*logging*/)
- {
- if (isbit != id)
- {
- /* sBIT has reduced the precision of the input: */
- pos = safecat(msg, sizeof msg, pos, ", sbit(");
- pos = safecatn(msg, sizeof msg, pos, vi->sbit);
- pos = safecat(msg, sizeof msg, pos, "): ");
- pos = safecatn(msg, sizeof msg, pos, isbit);
- }
- pos = safecat(msg, sizeof msg, pos, "/");
- /* The output is either "id/max" or "id sbit(sbit): isbit/max" */
- pos = safecatn(msg, sizeof msg, pos, vi->sbit_max);
- }
- pos = safecat(msg, sizeof msg, pos, ")");
-
- /* A component may have been multiplied (in linear space) by the
- * alpha value, 'compose' says whether this is relevant.
- */
- if (compose || pass != 0)
- {
- /* If any form of composition is being done report our
- * calculated linear value here (the code above doesn't record
- * the input value before composition is performed, so what
- * gets reported is the value after composition.)
- */
- if (use_input || pass != 0)
- {
- if (vi->file_inverse > 0)
- {
- pos = safecat(msg, sizeof msg, pos, "^");
- pos = safecatd(msg, sizeof msg, pos, vi->file_inverse, 2);
- }
-
- else
- pos = safecat(msg, sizeof msg, pos, "[linear]");
-
- pos = safecat(msg, sizeof msg, pos, "*(alpha)");
- pos = safecatd(msg, sizeof msg, pos, alpha, precision);
- }
-
- /* Now record the *linear* background value if it was used
- * (this function is not passed the original, non-linear,
- * value but it is contained in the test name.)
- */
- if (use_background)
- {
- pos = safecat(msg, sizeof msg, pos, use_input ? "+" : " ");
- pos = safecat(msg, sizeof msg, pos, "(background)");
- pos = safecatd(msg, sizeof msg, pos, background, precision);
- pos = safecat(msg, sizeof msg, pos, "*");
- pos = safecatd(msg, sizeof msg, pos, 1-alpha, precision);
- }
- }
-
- /* Report the calculated value (input_sample) and the linearized
- * libpng value (output) unless this is just a component gamma
- * correction.
- */
- if (compose || alpha < 0 || pass != 0)
- {
- pos = safecat(msg, sizeof msg, pos,
- pass != 0 ? " =\n\t" : " = ");
- pos = safecatd(msg, sizeof msg, pos, input_sample, precision);
- pos = safecat(msg, sizeof msg, pos, " (libpng: ");
- pos = safecatd(msg, sizeof msg, pos, output, precision);
- pos = safecat(msg, sizeof msg, pos, ")");
-
- /* Finally report the output gamma encoding, if any. */
- if (output_is_encoded)
- {
- pos = safecat(msg, sizeof msg, pos, " ^");
- pos = safecatd(msg, sizeof msg, pos, vi->screen_inverse, 2);
- pos = safecat(msg, sizeof msg, pos, "(to screen) =");
- }
-
- else
- pos = safecat(msg, sizeof msg, pos, " [screen is linear] =");
- }
-
- if ((!compose && alpha >= 0) || pass != 0)
- {
- if (pass != 0) /* logging */
- pos = safecat(msg, sizeof msg, pos, "\n\t[overall:");
-
- /* This is the non-composition case, the internal linear
- * values are irrelevant (though the log below will reveal
- * them.) Output a much shorter warning/error message and report
- * the overall gamma correction.
- */
- if (vi->gamma_correction > 0)
- {
- pos = safecat(msg, sizeof msg, pos, " ^");
- pos = safecatd(msg, sizeof msg, pos, vi->gamma_correction, 2);
- pos = safecat(msg, sizeof msg, pos, "(gamma correction) =");
- }
-
- else
- pos = safecat(msg, sizeof msg, pos,
- " [no gamma correction] =");
-
- if (pass != 0)
- pos = safecat(msg, sizeof msg, pos, "]");
- }
-
- /* This is our calculated encoded_sample which should (but does
- * not) match od:
- */
- pos = safecat(msg, sizeof msg, pos, pass != 0 ? "\n\t" : " ");
- pos = safecatd(msg, sizeof msg, pos, is_lo, 1);
- pos = safecat(msg, sizeof msg, pos, " < ");
- pos = safecatd(msg, sizeof msg, pos, encoded_sample, 1);
- pos = safecat(msg, sizeof msg, pos, " (libpng: ");
- pos = safecatn(msg, sizeof msg, pos, od);
- pos = safecat(msg, sizeof msg, pos, ")");
- pos = safecat(msg, sizeof msg, pos, "/");
- pos = safecatn(msg, sizeof msg, pos, outmax);
- pos = safecat(msg, sizeof msg, pos, " < ");
- pos = safecatd(msg, sizeof msg, pos, is_hi, 1);
-
- if (pass == 0) /* The error condition */
- {
-# ifdef PNG_WARNINGS_SUPPORTED
- png_warning(vi->pp, msg);
-# else
- store_warning(vi->pp, msg);
-# endif
- }
-
- else /* logging this value */
- store_verbose(&vi->dp->pm->this, vi->pp, pass, msg);
- }
- }
- }
-
- return i;
-}
-
-static void
-gamma_image_validate(gamma_display *dp, png_structp pp, png_infop pi)
-{
- /* Get some constants derived from the input and output file formats: */
- PNG_CONST png_store* PNG_CONST ps = dp->this.ps;
- PNG_CONST png_byte in_ct = dp->this.colour_type;
- PNG_CONST png_byte in_bd = dp->this.bit_depth;
- PNG_CONST png_uint_32 w = dp->this.w;
- PNG_CONST png_uint_32 h = dp->this.h;
- PNG_CONST size_t cbRow = dp->this.cbRow;
- PNG_CONST png_byte out_ct = png_get_color_type(pp, pi);
- PNG_CONST png_byte out_bd = png_get_bit_depth(pp, pi);
-
- /* There are three sources of error, firstly the quantization in the
- * file encoding, determined by sbit and/or the file depth, secondly
- * the output (screen) gamma and thirdly the output file encoding.
- *
- * Since this API receives the screen and file gamma in double
- * precision it is possible to calculate an exact answer given an input
- * pixel value. Therefore we assume that the *input* value is exact -
- * sample/maxsample - calculate the corresponding gamma corrected
- * output to the limits of double precision arithmetic and compare with
- * what libpng returns.
- *
- * Since the library must quantize the output to 8 or 16 bits there is
- * a fundamental limit on the accuracy of the output of +/-.5 - this
- * quantization limit is included in addition to the other limits
- * specified by the paramaters to the API. (Effectively, add .5
- * everywhere.)
- *
- * The behavior of the 'sbit' paramter is defined by section 12.5
- * (sample depth scaling) of the PNG spec. That section forces the
- * decoder to assume that the PNG values have been scaled if sBIT is
- * present:
- *
- * png-sample = floor( input-sample * (max-out/max-in) + .5);
- *
- * This means that only a subset of the possible PNG values should
- * appear in the input. However, the spec allows the encoder to use a
- * variety of approximations to the above and doesn't require any
- * restriction of the values produced.
- *
- * Nevertheless the spec requires that the upper 'sBIT' bits of the
- * value stored in a PNG file be the original sample bits.
- * Consequently the code below simply scales the top sbit bits by
- * (1<<sbit)-1 to obtain an original sample value.
- *
- * Because there is limited precision in the input it is arguable that
- * an acceptable result is any valid result from input-.5 to input+.5.
- * The basic tests below do not do this, however if 'use_input_precision'
- * is set a subsequent test is performed below.
- */
- PNG_CONST unsigned int samples_per_pixel = (out_ct & 2U) ? 3U : 1U;
- int processing;
- png_uint_32 y;
- PNG_CONST store_palette_entry *in_palette = dp->this.palette;
- PNG_CONST int in_is_transparent = dp->this.is_transparent;
- int out_npalette = -1;
- int out_is_transparent = 0; /* Just refers to the palette case */
- store_palette out_palette;
- validate_info vi;
-
- /* Check for row overwrite errors */
- store_image_check(dp->this.ps, pp, 0);
-
- /* Supply the input and output sample depths here - 8 for an indexed image,
- * otherwise the bit depth.
- */
- init_validate_info(&vi, dp, pp, in_ct==3?8:in_bd, out_ct==3?8:out_bd);
-
- processing = (vi.gamma_correction > 0 && !dp->threshold_test)
- || in_bd != out_bd || in_ct != out_ct || vi.do_background;
-
- /* TODO: FIX THIS: MAJOR BUG! If the transformations all happen inside
- * the palette there is no way of finding out, because libpng fails to
- * update the palette on png_read_update_info. Indeed, libpng doesn't
- * even do the required work until much later, when it doesn't have any
- * info pointer. Oops. For the moment 'processing' is turned off if
- * out_ct is palette.
- */
- if (in_ct == 3 && out_ct == 3)
- processing = 0;
-
- if (processing && out_ct == 3)
- out_is_transparent = read_palette(out_palette, &out_npalette, pp, pi);
-
- for (y=0; y<h; ++y)
- {
- png_const_bytep pRow = store_image_row(ps, pp, 0, y);
- png_byte std[STANDARD_ROWMAX];
-
- transform_row(pp, std, in_ct, in_bd, y);
-
- if (processing)
- {
- unsigned int x;
-
- for (x=0; x<w; ++x)
- {
- double alpha = 1; /* serves as a flag value */
-
- /* Record the palette index for index images. */
- PNG_CONST unsigned int in_index =
- in_ct == 3 ? sample(std, 3, in_bd, x, 0) : 256;
- PNG_CONST unsigned int out_index =
- out_ct == 3 ? sample(std, 3, out_bd, x, 0) : 256;
-
- /* Handle input alpha - png_set_background will cause the output
- * alpha to disappear so there is nothing to check.
- */
- if ((in_ct & PNG_COLOR_MASK_ALPHA) != 0 || (in_ct == 3 &&
- in_is_transparent))
- {
- PNG_CONST unsigned int input_alpha = in_ct == 3 ?
- dp->this.palette[in_index].alpha :
- sample(std, in_ct, in_bd, x, samples_per_pixel);
-
- unsigned int output_alpha = 65536 /* as a flag value */;
-
- if (out_ct == 3)
- {
- if (out_is_transparent)
- output_alpha = out_palette[out_index].alpha;
- }
-
- else if ((out_ct & PNG_COLOR_MASK_ALPHA) != 0)
- output_alpha = sample(pRow, out_ct, out_bd, x,
- samples_per_pixel);
-
- if (output_alpha != 65536)
- alpha = gamma_component_validate("alpha", &vi, input_alpha,
- output_alpha, -1/*alpha*/, 0/*background*/);
-
- else /* no alpha in output */
- {
- /* This is a copy of the calculation of 'i' above in order to
- * have the alpha value to use in the background calculation.
- */
- alpha = input_alpha >> vi.isbit_shift;
- alpha /= vi.sbit_max;
- }
- }
-
- /* Handle grayscale or RGB components. */
- if ((in_ct & PNG_COLOR_MASK_COLOR) == 0) /* grayscale */
- (void)gamma_component_validate("gray", &vi,
- sample(std, in_ct, in_bd, x, 0),
- sample(pRow, out_ct, out_bd, x, 0), alpha/*component*/,
- vi.background_red);
- else /* RGB or palette */
- {
- (void)gamma_component_validate("red", &vi,
- in_ct == 3 ? in_palette[in_index].red :
- sample(std, in_ct, in_bd, x, 0),
- out_ct == 3 ? out_palette[out_index].red :
- sample(pRow, out_ct, out_bd, x, 0),
- alpha/*component*/, vi.background_red);
-
- (void)gamma_component_validate("green", &vi,
- in_ct == 3 ? in_palette[in_index].green :
- sample(std, in_ct, in_bd, x, 1),
- out_ct == 3 ? out_palette[out_index].green :
- sample(pRow, out_ct, out_bd, x, 1),
- alpha/*component*/, vi.background_green);
-
- (void)gamma_component_validate("blue", &vi,
- in_ct == 3 ? in_palette[in_index].blue :
- sample(std, in_ct, in_bd, x, 2),
- out_ct == 3 ? out_palette[out_index].blue :
- sample(pRow, out_ct, out_bd, x, 2),
- alpha/*component*/, vi.background_blue);
- }
- }
- }
-
- else if (memcmp(std, pRow, cbRow) != 0)
- {
- char msg[64];
-
- /* No transform is expected on the threshold tests. */
- sprintf(msg, "gamma: below threshold row %d changed", y);
-
- png_error(pp, msg);
- }
- } /* row (y) loop */
-
- dp->this.ps->validated = 1;
-}
-
-static void
-gamma_end(png_structp pp, png_infop pi)
-{
- gamma_display *dp = voidcast(gamma_display*, png_get_progressive_ptr(pp));
-
- if (!dp->this.speed)
- gamma_image_validate(dp, pp, pi);
- else
- dp->this.ps->validated = 1;
-}
-
-/* A single test run checking a gamma transformation.
- *
- * maxabs: maximum absolute error as a fraction
- * maxout: maximum output error in the output units
- * maxpc: maximum percentage error (as a percentage)
- */
-static void
-gamma_test(png_modifier *pmIn, PNG_CONST png_byte colour_typeIn,
- PNG_CONST png_byte bit_depthIn, PNG_CONST int palette_numberIn,
- PNG_CONST int interlace_typeIn,
- PNG_CONST double file_gammaIn, PNG_CONST double screen_gammaIn,
- PNG_CONST png_byte sbitIn, PNG_CONST int threshold_testIn,
- PNG_CONST char *name,
- PNG_CONST int use_input_precisionIn, PNG_CONST int scale16In,
- PNG_CONST int expand16In, PNG_CONST int do_backgroundIn,
- PNG_CONST png_color_16 *bkgd_colorIn, double bkgd_gammaIn)
-{
- gamma_display d;
- context(&pmIn->this, fault);
-
- gamma_display_init(&d, pmIn, FILEID(colour_typeIn, bit_depthIn,
- palette_numberIn, interlace_typeIn, 0, 0, 0),
- file_gammaIn, screen_gammaIn, sbitIn,
- threshold_testIn, use_input_precisionIn, scale16In,
- expand16In, do_backgroundIn, bkgd_colorIn, bkgd_gammaIn);
-
- Try
- {
- png_structp pp;
- png_infop pi;
- gama_modification gama_mod;
- srgb_modification srgb_mod;
- sbit_modification sbit_mod;
-
- /* For the moment don't use the png_modifier support here. */
- d.pm->encoding_counter = 0;
- modifier_set_encoding(d.pm); /* Just resets everything */
- d.pm->current_gamma = d.file_gamma;
-
- /* Make an appropriate modifier to set the PNG file gamma to the
- * given gamma value and the sBIT chunk to the given precision.
- */
- d.pm->modifications = NULL;
- gama_modification_init(&gama_mod, d.pm, d.file_gamma);
- srgb_modification_init(&srgb_mod, d.pm, 127 /*delete*/);
- if (d.sbit > 0)
- sbit_modification_init(&sbit_mod, d.pm, d.sbit);
-
- modification_reset(d.pm->modifications);
-
- /* Get a png_struct for writing the image. */
- pp = set_modifier_for_read(d.pm, &pi, d.this.id, name);
- standard_palette_init(&d.this);
-
- /* Introduce the correct read function. */
- if (d.pm->this.progressive)
- {
- /* Share the row function with the standard implementation. */
- png_set_progressive_read_fn(pp, &d, gamma_info, progressive_row,
- gamma_end);
-
- /* Now feed data into the reader until we reach the end: */
- modifier_progressive_read(d.pm, pp, pi);
- }
- else
- {
- /* modifier_read expects a png_modifier* */
- png_set_read_fn(pp, d.pm, modifier_read);
-
- /* Check the header values: */
- png_read_info(pp, pi);
-
- /* Process the 'info' requirements. Only one image is generated */
- gamma_info_imp(&d, pp, pi);
-
- sequential_row(&d.this, pp, pi, -1, 0);
-
- if (!d.this.speed)
- gamma_image_validate(&d, pp, pi);
- else
- d.this.ps->validated = 1;
- }
-
- modifier_reset(d.pm);
-
- if (d.pm->log && !d.threshold_test && !d.this.speed)
- fprintf(stderr, "%d bit %s %s: max error %f (%.2g, %2g%%)\n",
- d.this.bit_depth, colour_types[d.this.colour_type], name,
- d.maxerrout, d.maxerrabs, 100*d.maxerrpc);
-
- /* Log the summary values too. */
- if (d.this.colour_type == 0 || d.this.colour_type == 4)
- {
- switch (d.this.bit_depth)
- {
- case 1:
- break;
-
- case 2:
- if (d.maxerrout > d.pm->error_gray_2)
- d.pm->error_gray_2 = d.maxerrout;
-
- break;
-
- case 4:
- if (d.maxerrout > d.pm->error_gray_4)
- d.pm->error_gray_4 = d.maxerrout;
-
- break;
-
- case 8:
- if (d.maxerrout > d.pm->error_gray_8)
- d.pm->error_gray_8 = d.maxerrout;
-
- break;
-
- case 16:
- if (d.maxerrout > d.pm->error_gray_16)
- d.pm->error_gray_16 = d.maxerrout;
-
- break;
-
- default:
- png_error(pp, "bad bit depth (internal: 1)");
- }
- }
-
- else if (d.this.colour_type == 2 || d.this.colour_type == 6)
- {
- switch (d.this.bit_depth)
- {
- case 8:
-
- if (d.maxerrout > d.pm->error_color_8)
- d.pm->error_color_8 = d.maxerrout;
-
- break;
-
- case 16:
-
- if (d.maxerrout > d.pm->error_color_16)
- d.pm->error_color_16 = d.maxerrout;
-
- break;
-
- default:
- png_error(pp, "bad bit depth (internal: 2)");
- }
- }
-
- else if (d.this.colour_type == 3)
- {
- if (d.maxerrout > d.pm->error_indexed)
- d.pm->error_indexed = d.maxerrout;
- }
- }
-
- Catch(fault)
- modifier_reset((png_modifier*)fault);
-}
-
-static void gamma_threshold_test(png_modifier *pm, png_byte colour_type,
- png_byte bit_depth, int interlace_type, double file_gamma,
- double screen_gamma)
-{
- size_t pos = 0;
- char name[64];
- pos = safecat(name, sizeof name, pos, "threshold ");
- pos = safecatd(name, sizeof name, pos, file_gamma, 3);
- pos = safecat(name, sizeof name, pos, "/");
- pos = safecatd(name, sizeof name, pos, screen_gamma, 3);
-
- (void)gamma_test(pm, colour_type, bit_depth, 0/*palette*/, interlace_type,
- file_gamma, screen_gamma, 0/*sBIT*/, 1/*threshold test*/, name,
- 0 /*no input precision*/,
- 0 /*no scale16*/, 0 /*no expand16*/, 0 /*no background*/, 0 /*hence*/,
- 0 /*no background gamma*/);
-}
-
-static void
-perform_gamma_threshold_tests(png_modifier *pm)
-{
- png_byte colour_type = 0;
- png_byte bit_depth = 0;
- int palette_number = 0;
-
- /* Don't test more than one instance of each palette - it's pointless, in
- * fact this test is somewhat excessive since libpng doesn't make this
- * decision based on colour type or bit depth!
- */
- while (next_format(&colour_type, &bit_depth, &palette_number))
- if (palette_number == 0)
- {
- double test_gamma = 1.0;
- while (test_gamma >= .4)
- {
- /* There's little point testing the interlacing vs non-interlacing,
- * but this can be set from the command line.
- */
- gamma_threshold_test(pm, colour_type, bit_depth, pm->interlace_type,
- test_gamma, 1/test_gamma);
- test_gamma *= .95;
- }
-
- /* And a special test for sRGB */
- gamma_threshold_test(pm, colour_type, bit_depth, pm->interlace_type,
- .45455, 2.2);
-
- if (fail(pm))
- return;
- }
-}
-
-static void gamma_transform_test(png_modifier *pm,
- PNG_CONST png_byte colour_type, PNG_CONST png_byte bit_depth,
- PNG_CONST int palette_number,
- PNG_CONST int interlace_type, PNG_CONST double file_gamma,
- PNG_CONST double screen_gamma, PNG_CONST png_byte sbit,
- PNG_CONST int use_input_precision, PNG_CONST int scale16)
-{
- size_t pos = 0;
- char name[64];
-
- if (sbit != bit_depth && sbit != 0)
- {
- pos = safecat(name, sizeof name, pos, "sbit(");
- pos = safecatn(name, sizeof name, pos, sbit);
- pos = safecat(name, sizeof name, pos, ") ");
- }
-
- else
- pos = safecat(name, sizeof name, pos, "gamma ");
-
- if (scale16)
- pos = safecat(name, sizeof name, pos, "16to8 ");
-
- pos = safecatd(name, sizeof name, pos, file_gamma, 3);
- pos = safecat(name, sizeof name, pos, "->");
- pos = safecatd(name, sizeof name, pos, screen_gamma, 3);
-
- gamma_test(pm, colour_type, bit_depth, palette_number, interlace_type,
- file_gamma, screen_gamma, sbit, 0, name, use_input_precision,
- scale16, pm->test_gamma_expand16, 0 , 0, 0);
-}
-
-static void perform_gamma_transform_tests(png_modifier *pm)
-{
- png_byte colour_type = 0;
- png_byte bit_depth = 0;
- int palette_number = 0;
-
- while (next_format(&colour_type, &bit_depth, &palette_number))
- {
- unsigned int i, j;
-
- for (i=0; i<pm->ngamma_tests; ++i) for (j=0; j<pm->ngamma_tests; ++j)
- if (i != j)
- {
- gamma_transform_test(pm, colour_type, bit_depth, palette_number,
- pm->interlace_type, 1/pm->gammas[i], pm->gammas[j], 0/*sBIT*/,
- pm->use_input_precision, 0 /*do not scale16*/);
-
- if (fail(pm))
- return;
- }
- }
-}
-
-static void perform_gamma_sbit_tests(png_modifier *pm)
-{
- png_byte sbit;
-
- /* The only interesting cases are colour and grayscale, alpha is ignored here
- * for overall speed. Only bit depths where sbit is less than the bit depth
- * are tested.
- */
- for (sbit=pm->sbitlow; sbit<(1<<READ_BDHI); ++sbit)
- {
- png_byte colour_type, bit_depth;
- int npalette;
-
- colour_type = bit_depth = 0;
- npalette = 0;
-
- while (next_format(&colour_type, &bit_depth, &npalette))
- if ((colour_type & PNG_COLOR_MASK_ALPHA) == 0 &&
- ((colour_type == 3 && sbit < 8) ||
- (colour_type != 3 && sbit < bit_depth)))
- {
- unsigned int i;
-
- for (i=0; i<pm->ngamma_tests; ++i)
- {
- unsigned int j;
-
- for (j=0; j<pm->ngamma_tests; ++j) if (i != j)
- {
- gamma_transform_test(pm, colour_type, bit_depth, npalette,
- pm->interlace_type, 1/pm->gammas[i], pm->gammas[j],
- sbit, pm->use_input_precision_sbit, 0 /*scale16*/);
-
- if (fail(pm))
- return;
- }
- }
- }
- }
-}
-
-/* Note that this requires a 16 bit source image but produces 8 bit output, so
- * we only need the 16bit write support, but the 16 bit images are only
- * generated if DO_16BIT is defined.
- */
-#ifdef DO_16BIT
-static void perform_gamma_scale16_tests(png_modifier *pm)
-{
-# ifndef PNG_MAX_GAMMA_8
-# define PNG_MAX_GAMMA_8 11
-# endif
- /* Include the alpha cases here. Note that sbit matches the internal value
- * used by the library - otherwise we will get spurious errors from the
- * internal sbit style approximation.
- *
- * The threshold test is here because otherwise the 16 to 8 conversion will
- * proceed *without* gamma correction, and the tests above will fail (but not
- * by much) - this could be fixed, it only appears with the -g option.
- */
- unsigned int i, j;
- for (i=0; i<pm->ngamma_tests; ++i)
- {
- for (j=0; j<pm->ngamma_tests; ++j)
- {
- if (i != j &&
- fabs(pm->gammas[j]/pm->gammas[i]-1) >= PNG_GAMMA_THRESHOLD)
- {
- gamma_transform_test(pm, 0, 16, 0, pm->interlace_type,
- 1/pm->gammas[i], pm->gammas[j], PNG_MAX_GAMMA_8,
- pm->use_input_precision_16to8, 1 /*scale16*/);
-
- if (fail(pm))
- return;
-
- gamma_transform_test(pm, 2, 16, 0, pm->interlace_type,
- 1/pm->gammas[i], pm->gammas[j], PNG_MAX_GAMMA_8,
- pm->use_input_precision_16to8, 1 /*scale16*/);
-
- if (fail(pm))
- return;
-
- gamma_transform_test(pm, 4, 16, 0, pm->interlace_type,
- 1/pm->gammas[i], pm->gammas[j], PNG_MAX_GAMMA_8,
- pm->use_input_precision_16to8, 1 /*scale16*/);
-
- if (fail(pm))
- return;
-
- gamma_transform_test(pm, 6, 16, 0, pm->interlace_type,
- 1/pm->gammas[i], pm->gammas[j], PNG_MAX_GAMMA_8,
- pm->use_input_precision_16to8, 1 /*scale16*/);
-
- if (fail(pm))
- return;
- }
- }
- }
-}
-#endif /* 16 to 8 bit conversion */
-
-#if defined PNG_READ_BACKGROUND_SUPPORTED ||\
- defined PNG_READ_ALPHA_MODE_SUPPORTED
-static void gamma_composition_test(png_modifier *pm,
- PNG_CONST png_byte colour_type, PNG_CONST png_byte bit_depth,
- PNG_CONST int palette_number,
- PNG_CONST int interlace_type, PNG_CONST double file_gamma,
- PNG_CONST double screen_gamma,
- PNG_CONST int use_input_precision, PNG_CONST int do_background,
- PNG_CONST int expand_16)
-{
- size_t pos = 0;
- png_const_charp base;
- double bg;
- char name[128];
- png_color_16 background;
-
- /* Make up a name and get an appropriate background gamma value. */
- switch (do_background)
- {
- default:
- base = "";
- bg = 4; /* should not be used */
- break;
- case PNG_BACKGROUND_GAMMA_SCREEN:
- base = " bckg(Screen):";
- bg = 1/screen_gamma;
- break;
- case PNG_BACKGROUND_GAMMA_FILE:
- base = " bckg(File):";
- bg = file_gamma;
- break;
- case PNG_BACKGROUND_GAMMA_UNIQUE:
- base = " bckg(Unique):";
- /* This tests the handling of a unique value, the math is such that the
- * value tends to be <1, but is neither screen nor file (even if they
- * match!)
- */
- bg = (file_gamma + screen_gamma) / 3;
- break;
-#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
- case ALPHA_MODE_OFFSET + PNG_ALPHA_PNG:
- base = " alpha(PNG)";
- bg = 4; /* should not be used */
- break;
- case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD:
- base = " alpha(Porter-Duff)";
- bg = 4; /* should not be used */
- break;
- case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED:
- base = " alpha(Optimized)";
- bg = 4; /* should not be used */
- break;
- case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN:
- base = " alpha(Broken)";
- bg = 4; /* should not be used */
- break;
-#endif
- }
-
- /* Use random background values - the background is always presented in the
- * output space (8 or 16 bit components).
- */
- if (expand_16 || bit_depth == 16)
- {
- png_uint_32 r = random_32();
-
- background.red = (png_uint_16)r;
- background.green = (png_uint_16)(r >> 16);
- r = random_32();
- background.blue = (png_uint_16)r;
- background.gray = (png_uint_16)(r >> 16);
- }
-
- else /* 8 bit colors */
- {
- png_uint_32 r = random_32();
-
- background.red = (png_byte)r;
- background.green = (png_byte)(r >> 8);
- background.blue = (png_byte)(r >> 16);
- background.gray = (png_byte)(r >> 24);
- }
-
- background.index = 193; /* rgb(193,193,193) to detect errors */
- if (!(colour_type & PNG_COLOR_MASK_COLOR))
- {
- /* Grayscale input, we do not convert to RGB (TBD), so we must set the
- * background to gray - else libpng seems to fail.
- */
- background.red = background.green = background.blue = background.gray;
- }
-
- pos = safecat(name, sizeof name, pos, "gamma ");
- pos = safecatd(name, sizeof name, pos, file_gamma, 3);
- pos = safecat(name, sizeof name, pos, "->");
- pos = safecatd(name, sizeof name, pos, screen_gamma, 3);
-
- pos = safecat(name, sizeof name, pos, base);
- if (do_background < ALPHA_MODE_OFFSET)
- {
- /* Include the background color and gamma in the name: */
- pos = safecat(name, sizeof name, pos, "(");
- /* This assumes no expand gray->rgb - the current code won't handle that!
- */
- if (colour_type & PNG_COLOR_MASK_COLOR)
- {
- pos = safecatn(name, sizeof name, pos, background.red);
- pos = safecat(name, sizeof name, pos, ",");
- pos = safecatn(name, sizeof name, pos, background.green);
- pos = safecat(name, sizeof name, pos, ",");
- pos = safecatn(name, sizeof name, pos, background.blue);
- }
- else
- pos = safecatn(name, sizeof name, pos, background.gray);
- pos = safecat(name, sizeof name, pos, ")^");
- pos = safecatd(name, sizeof name, pos, bg, 3);
- }
-
- gamma_test(pm, colour_type, bit_depth, palette_number, interlace_type,
- file_gamma, screen_gamma, 0/*sBIT*/, 0, name, use_input_precision,
- 0/*strip 16*/, expand_16, do_background, &background, bg);
-}
-
-
-static void
-perform_gamma_composition_tests(png_modifier *pm, int do_background,
- int expand_16)
-{
- png_byte colour_type = 0;
- png_byte bit_depth = 0;
- int palette_number = 0;
-
- /* Skip the non-alpha cases - there is no setting of a transparency colour at
- * present.
- */
- while (next_format(&colour_type, &bit_depth, &palette_number))
- if ((colour_type & PNG_COLOR_MASK_ALPHA) != 0)
- {
- unsigned int i, j;
-
- /* Don't skip the i==j case here - it's relevant. */
- for (i=0; i<pm->ngamma_tests; ++i) for (j=0; j<pm->ngamma_tests; ++j)
- {
- gamma_composition_test(pm, colour_type, bit_depth, palette_number,
- pm->interlace_type, 1/pm->gammas[i], pm->gammas[j],
- pm->use_input_precision, do_background, expand_16);
-
- if (fail(pm))
- return;
- }
- }
-}
-#endif /* READ_BACKGROUND || READ_ALPHA_MODE */
-
-static void
-init_gamma_errors(png_modifier *pm)
-{
- pm->error_gray_2 = pm->error_gray_4 = pm->error_gray_8 = 0;
- pm->error_color_8 = 0;
- pm->error_indexed = 0;
- pm->error_gray_16 = pm->error_color_16 = 0;
-}
-
-static void
-summarize_gamma_errors(png_modifier *pm, png_const_charp who, int low_bit_depth)
-{
- if (who)
- printf("Gamma correction with %s:\n", who);
-
- if (low_bit_depth)
- {
- printf(" 2 bit gray: %.5f\n", pm->error_gray_2);
- printf(" 4 bit gray: %.5f\n", pm->error_gray_4);
- printf(" 8 bit gray: %.5f\n", pm->error_gray_8);
- printf(" 8 bit color: %.5f\n", pm->error_color_8);
- printf(" indexed: %.5f\n", pm->error_indexed);
- }
-
-#ifdef DO_16BIT
- printf(" 16 bit gray: %.5f\n", pm->error_gray_16);
- printf(" 16 bit color: %.5f\n", pm->error_color_16);
-#endif
-}
-
-static void
-perform_gamma_test(png_modifier *pm, int summary)
-{
- /*TODO: remove this*/
- /* Save certain values for the temporary overrides below. */
- unsigned int calculations_use_input_precision =
- pm->calculations_use_input_precision;
- double maxout8 = pm->maxout8;
-
- /* First some arbitrary no-transform tests: */
- if (!pm->this.speed && pm->test_gamma_threshold)
- {
- perform_gamma_threshold_tests(pm);
-
- if (fail(pm))
- return;
- }
-
- /* Now some real transforms. */
- if (pm->test_gamma_transform)
- {
- init_gamma_errors(pm);
- /*TODO: remove this. Necessary because the current libpng
- * implementation works in 8 bits:
- */
- if (pm->test_gamma_expand16)
- pm->calculations_use_input_precision = 1;
- perform_gamma_transform_tests(pm);
- if (!calculations_use_input_precision)
- pm->calculations_use_input_precision = 0;
-
- if (summary)
- {
- printf("Gamma correction error summary\n\n");
- printf("The printed value is the maximum error in the pixel values\n");
- printf("calculated by the libpng gamma correction code. The error\n");
- printf("is calculated as the difference between the output pixel\n");
- printf("value (always an integer) and the ideal value from the\n");
- printf("libpng specification (typically not an integer).\n\n");
-
- printf("Expect this value to be less than .5 for 8 bit formats,\n");
- printf("less than 1 for formats with fewer than 8 bits and a small\n");
- printf("number (typically less than 5) for the 16 bit formats.\n");
- printf("For performance reasons the value for 16 bit formats\n");
- printf("increases when the image file includes an sBIT chunk.\n\n");
-
- summarize_gamma_errors(pm, 0/*who*/, 1);
- }
- }
-
- /* The sbit tests produce much larger errors: */
- if (pm->test_gamma_sbit)
- {
- init_gamma_errors(pm);
- perform_gamma_sbit_tests(pm);
-
- if (summary)
- summarize_gamma_errors(pm, "sBIT", pm->sbitlow < 8U);
- }
-
-#ifdef DO_16BIT /* Should be READ_16BIT_SUPPORTED */
- if (pm->test_gamma_scale16)
- {
- /* The 16 to 8 bit strip operations: */
- init_gamma_errors(pm);
- perform_gamma_scale16_tests(pm);
-
- if (summary)
- {
- printf("Gamma correction with 16 to 8 bit reduction:\n");
- printf(" 16 bit gray: %.5f\n", pm->error_gray_16);
- printf(" 16 bit color: %.5f\n", pm->error_color_16);
- }
- }
-#endif
-
-#ifdef PNG_READ_BACKGROUND_SUPPORTED
- if (pm->test_gamma_background)
- {
- init_gamma_errors(pm);
-
- /*TODO: remove this. Necessary because the current libpng
- * implementation works in 8 bits:
- */
- if (pm->test_gamma_expand16)
- {
- pm->calculations_use_input_precision = 1;
- pm->maxout8 = .499; /* because the 16 bit background is smashed */
- }
- perform_gamma_composition_tests(pm, PNG_BACKGROUND_GAMMA_UNIQUE,
- pm->test_gamma_expand16);
- if (!calculations_use_input_precision)
- pm->calculations_use_input_precision = 0;
- pm->maxout8 = maxout8;
-
- if (summary)
- summarize_gamma_errors(pm, "background", 1);
- }
-#endif
-
-#ifdef PNG_READ_ALPHA_MODE_SUPPORTED
- if (pm->test_gamma_alpha_mode)
- {
- int do_background;
-
- init_gamma_errors(pm);
-
- /*TODO: remove this. Necessary because the current libpng
- * implementation works in 8 bits:
- */
- if (pm->test_gamma_expand16)
- pm->calculations_use_input_precision = 1;
- for (do_background = ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD;
- do_background <= ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN && !fail(pm);
- ++do_background)
- perform_gamma_composition_tests(pm, do_background,
- pm->test_gamma_expand16);
- if (!calculations_use_input_precision)
- pm->calculations_use_input_precision = 0;
-
- if (summary)
- summarize_gamma_errors(pm, "alpha mode", 1);
- }
-#endif
-}
-#endif /* PNG_READ_GAMMA_SUPPORTED */
-
-/* INTERLACE MACRO VALIDATION */
-/* This is copied verbatim from the specification, it is simply the pass
- * number in which each pixel in each 8x8 tile appears. The array must
- * be indexed adam7[y][x] and notice that the pass numbers are based at
- * 1, not 0 - the base libpng uses.
- */
-static PNG_CONST
-png_byte adam7[8][8] =
-{
- { 1,6,4,6,2,6,4,6 },
- { 7,7,7,7,7,7,7,7 },
- { 5,6,5,6,5,6,5,6 },
- { 7,7,7,7,7,7,7,7 },
- { 3,6,4,6,3,6,4,6 },
- { 7,7,7,7,7,7,7,7 },
- { 5,6,5,6,5,6,5,6 },
- { 7,7,7,7,7,7,7,7 }
-};
-
-/* This routine validates all the interlace support macros in png.h for
- * a variety of valid PNG widths and heights. It uses a number of similarly
- * named internal routines that feed off the above array.
- */
-static png_uint_32
-png_pass_start_row(int pass)
-{
- int x, y;
- ++pass;
- for (y=0; y<8; ++y) for (x=0; x<8; ++x) if (adam7[y][x] == pass)
- return y;
- return 0xf;
-}
-
-static png_uint_32
-png_pass_start_col(int pass)
-{
- int x, y;
- ++pass;
- for (x=0; x<8; ++x) for (y=0; y<8; ++y) if (adam7[y][x] == pass)
- return x;
- return 0xf;
-}
-
-static int
-png_pass_row_shift(int pass)
-{
- int x, y, base=(-1), inc=8;
- ++pass;
- for (y=0; y<8; ++y) for (x=0; x<8; ++x) if (adam7[y][x] == pass)
- {
- if (base == (-1))
- base = y;
- else if (base == y)
- {}
- else if (inc == y-base)
- base=y;
- else if (inc == 8)
- inc = y-base, base=y;
- else if (inc != y-base)
- return 0xff; /* error - more than one 'inc' value! */
- }
-
- if (base == (-1)) return 0xfe; /* error - no row in pass! */
-
- /* The shift is always 1, 2 or 3 - no pass has all the rows! */
- switch (inc)
- {
-case 2: return 1;
-case 4: return 2;
-case 8: return 3;
-default: break;
- }
-
- /* error - unrecognized 'inc' */
- return (inc << 8) + 0xfd;
-}
-
-static int
-png_pass_col_shift(int pass)
-{
- int x, y, base=(-1), inc=8;
- ++pass;
- for (x=0; x<8; ++x) for (y=0; y<8; ++y) if (adam7[y][x] == pass)
- {
- if (base == (-1))
- base = x;
- else if (base == x)
- {}
- else if (inc == x-base)
- base=x;
- else if (inc == 8)
- inc = x-base, base=x;
- else if (inc != x-base)
- return 0xff; /* error - more than one 'inc' value! */
- }
-
- if (base == (-1)) return 0xfe; /* error - no row in pass! */
-
- /* The shift is always 1, 2 or 3 - no pass has all the rows! */
- switch (inc)
- {
-case 1: return 0; /* pass 7 has all the columns */
-case 2: return 1;
-case 4: return 2;
-case 8: return 3;
-default: break;
- }
-
- /* error - unrecognized 'inc' */
- return (inc << 8) + 0xfd;
-}
-
-static png_uint_32
-png_row_from_pass_row(png_uint_32 yIn, int pass)
-{
- /* By examination of the array: */
- switch (pass)
- {
-case 0: return yIn * 8;
-case 1: return yIn * 8;
-case 2: return yIn * 8 + 4;
-case 3: return yIn * 4;
-case 4: return yIn * 4 + 2;
-case 5: return yIn * 2;
-case 6: return yIn * 2 + 1;
-default: break;
- }
-
- return 0xff; /* bad pass number */
-}
-
-static png_uint_32
-png_col_from_pass_col(png_uint_32 xIn, int pass)
-{
- /* By examination of the array: */
- switch (pass)
- {
-case 0: return xIn * 8;
-case 1: return xIn * 8 + 4;
-case 2: return xIn * 4;
-case 3: return xIn * 4 + 2;
-case 4: return xIn * 2;
-case 5: return xIn * 2 + 1;
-case 6: return xIn;
-default: break;
- }
-
- return 0xff; /* bad pass number */
-}
-
-static int
-png_row_in_interlace_pass(png_uint_32 y, int pass)
-{
- /* Is row 'y' in pass 'pass'? */
- int x;
- y &= 7;
- ++pass;
- for (x=0; x<8; ++x) if (adam7[y][x] == pass)
- return 1;
-
- return 0;
-}
-
-static int
-png_col_in_interlace_pass(png_uint_32 x, int pass)
-{
- /* Is column 'x' in pass 'pass'? */
- int y;
- x &= 7;
- ++pass;
- for (y=0; y<8; ++y) if (adam7[y][x] == pass)
- return 1;
-
- return 0;
-}
-
-static png_uint_32
-png_pass_rows(png_uint_32 height, int pass)
-{
- png_uint_32 tiles = height>>3;
- png_uint_32 rows = 0;
- unsigned int x, y;
-
- height &= 7;
- ++pass;
- for (y=0; y<8; ++y) for (x=0; x<8; ++x) if (adam7[y][x] == pass)
- {
- rows += tiles;
- if (y < height) ++rows;
- break; /* i.e. break the 'x', column, loop. */
- }
-
- return rows;
-}
-
-static png_uint_32
-png_pass_cols(png_uint_32 width, int pass)
-{
- png_uint_32 tiles = width>>3;
- png_uint_32 cols = 0;
- unsigned int x, y;
-
- width &= 7;
- ++pass;
- for (x=0; x<8; ++x) for (y=0; y<8; ++y) if (adam7[y][x] == pass)
- {
- cols += tiles;
- if (x < width) ++cols;
- break; /* i.e. break the 'y', row, loop. */
- }
-
- return cols;
-}
-
-static void
-perform_interlace_macro_validation(void)
-{
- /* The macros to validate, first those that depend only on pass:
- *
- * PNG_PASS_START_ROW(pass)
- * PNG_PASS_START_COL(pass)
- * PNG_PASS_ROW_SHIFT(pass)
- * PNG_PASS_COL_SHIFT(pass)
- */
- int pass;
-
- for (pass=0; pass<7; ++pass)
- {
- png_uint_32 m, f, v;
-
- m = PNG_PASS_START_ROW(pass);
- f = png_pass_start_row(pass);
- if (m != f)
- {
- fprintf(stderr, "PNG_PASS_START_ROW(%d) = %u != %x\n", pass, m, f);
- exit(1);
- }
-
- m = PNG_PASS_START_COL(pass);
- f = png_pass_start_col(pass);
- if (m != f)
- {
- fprintf(stderr, "PNG_PASS_START_COL(%d) = %u != %x\n", pass, m, f);
- exit(1);
- }
-
- m = PNG_PASS_ROW_SHIFT(pass);
- f = png_pass_row_shift(pass);
- if (m != f)
- {
- fprintf(stderr, "PNG_PASS_ROW_SHIFT(%d) = %u != %x\n", pass, m, f);
- exit(1);
- }
-
- m = PNG_PASS_COL_SHIFT(pass);
- f = png_pass_col_shift(pass);
- if (m != f)
- {
- fprintf(stderr, "PNG_PASS_COL_SHIFT(%d) = %u != %x\n", pass, m, f);
- exit(1);
- }
-
- /* Macros that depend on the image or sub-image height too:
- *
- * PNG_PASS_ROWS(height, pass)
- * PNG_PASS_COLS(width, pass)
- * PNG_ROW_FROM_PASS_ROW(yIn, pass)
- * PNG_COL_FROM_PASS_COL(xIn, pass)
- * PNG_ROW_IN_INTERLACE_PASS(y, pass)
- * PNG_COL_IN_INTERLACE_PASS(x, pass)
- */
- for (v=0;;)
- {
- /* First the base 0 stuff: */
- m = PNG_ROW_FROM_PASS_ROW(v, pass);
- f = png_row_from_pass_row(v, pass);
- if (m != f)
- {
- fprintf(stderr, "PNG_ROW_FROM_PASS_ROW(%u, %d) = %u != %x\n",
- v, pass, m, f);
- exit(1);
- }
-
- m = PNG_COL_FROM_PASS_COL(v, pass);
- f = png_col_from_pass_col(v, pass);
- if (m != f)
- {
- fprintf(stderr, "PNG_COL_FROM_PASS_COL(%u, %d) = %u != %x\n",
- v, pass, m, f);
- exit(1);
- }
-
- m = PNG_ROW_IN_INTERLACE_PASS(v, pass);
- f = png_row_in_interlace_pass(v, pass);
- if (m != f)
- {
- fprintf(stderr, "PNG_ROW_IN_INTERLACE_PASS(%u, %d) = %u != %x\n",
- v, pass, m, f);
- exit(1);
- }
-
- m = PNG_COL_IN_INTERLACE_PASS(v, pass);
- f = png_col_in_interlace_pass(v, pass);
- if (m != f)
- {
- fprintf(stderr, "PNG_COL_IN_INTERLACE_PASS(%u, %d) = %u != %x\n",
- v, pass, m, f);
- exit(1);
- }
-
- /* Then the base 1 stuff: */
- ++v;
- m = PNG_PASS_ROWS(v, pass);
- f = png_pass_rows(v, pass);
- if (m != f)
- {
- fprintf(stderr, "PNG_PASS_ROWS(%u, %d) = %u != %x\n",
- v, pass, m, f);
- exit(1);
- }
-
- m = PNG_PASS_COLS(v, pass);
- f = png_pass_cols(v, pass);
- if (m != f)
- {
- fprintf(stderr, "PNG_PASS_COLS(%u, %d) = %u != %x\n",
- v, pass, m, f);
- exit(1);
- }
-
- /* Move to the next v - the stepping algorithm starts skipping
- * values above 1024.
- */
- if (v > 1024)
- {
- if (v == PNG_UINT_31_MAX)
- break;
-
- v = (v << 1) ^ v;
- if (v >= PNG_UINT_31_MAX)
- v = PNG_UINT_31_MAX-1;
- }
- }
- }
-}
-
-/* Test color encodings. These values are back-calculated from the published
- * chromaticities. The values are accurate to about 14 decimal places; 15 are
- * given. These values are much more accurate than the ones given in the spec,
- * which typically don't exceed 4 decimal places. This allows testing of the
- * libpng code to its theoretical accuracy of 4 decimal places. (If pngvalid
- * used the published errors the 'slack' permitted would have to be +/-.5E-4 or
- * more.)
- *
- * The png_modifier code assumes that encodings[0] is sRGB and treats it
- * specially: do not change the first entry in this list!
- */
-static PNG_CONST color_encoding test_encodings[] =
-{
-/* sRGB: must be first in this list! */
-/*gamma:*/ { 1/2.2,
-/*red: */ { 0.412390799265959, 0.212639005871510, 0.019330818715592 },
-/*green:*/ { 0.357584339383878, 0.715168678767756, 0.119194779794626 },
-/*blue: */ { 0.180480788401834, 0.072192315360734, 0.950532152249660} },
-/* Kodak ProPhoto (wide gamut) */
-/*gamma:*/ { 1/1.6 /*approximate: uses 1.8 power law compared to sRGB 2.4*/,
-/*red: */ { 0.797760489672303, 0.288071128229293, 0.000000000000000 },
-/*green:*/ { 0.135185837175740, 0.711843217810102, 0.000000000000000 },
-/*blue: */ { 0.031349349581525, 0.000085653960605, 0.825104602510460} },
-/* Adobe RGB (1998) */
-/*gamma:*/ { 1/(2+51./256),
-/*red: */ { 0.576669042910131, 0.297344975250536, 0.027031361386412 },
-/*green:*/ { 0.185558237906546, 0.627363566255466, 0.070688852535827 },
-/*blue: */ { 0.188228646234995, 0.075291458493998, 0.991337536837639} },
-/* Adobe Wide Gamut RGB */
-/*gamma:*/ { 1/(2+51./256),
-/*red: */ { 0.716500716779386, 0.258728243040113, 0.000000000000000 },
-/*green:*/ { 0.101020574397477, 0.724682314948566, 0.051211818965388 },
-/*blue: */ { 0.146774385252705, 0.016589442011321, 0.773892783545073} },
-};
-
-/* main program */
-int main(int argc, PNG_CONST char **argv)
-{
- volatile int summary = 1; /* Print the error summary at the end */
- volatile int memstats = 0; /* Print memory statistics at the end */
-
- /* Create the given output file on success: */
- PNG_CONST char *volatile touch = NULL;
-
- /* This is an array of standard gamma values (believe it or not I've seen
- * every one of these mentioned somewhere.)
- *
- * In the following list the most useful values are first!
- */
- static double
- gammas[]={2.2, 1.0, 2.2/1.45, 1.8, 1.5, 2.4, 2.5, 2.62, 2.9};
-
- /* This records the command and arguments: */
- size_t cp = 0;
- char command[1024];
-
- png_modifier pm;
- context(&pm.this, fault);
-
- modifier_init(&pm);
-
- /* Preallocate the image buffer, because we know how big it needs to be,
- * note that, for testing purposes, it is deliberately mis-aligned by tag
- * bytes either side. All rows have an additional five bytes of padding for
- * overwrite checking.
- */
- store_ensure_image(&pm.this, NULL, 2, TRANSFORM_ROWMAX, TRANSFORM_HEIGHTMAX);
-
- /* Don't give argv[0], it's normally some horrible libtool string: */
- cp = safecat(command, sizeof command, cp, "pngvalid");
-
- /* Default to error on warning: */
- pm.this.treat_warnings_as_errors = 1;
-
- /* Store the test gammas */
- pm.gammas = gammas;
- pm.ngammas = (sizeof gammas) / (sizeof gammas[0]);
- pm.ngamma_tests = 0; /* default to off */
-
- /* And the test encodings */
- pm.encodings = test_encodings;
- pm.nencodings = (sizeof test_encodings) / (sizeof test_encodings[0]);
-
- pm.sbitlow = 8U; /* because libpng doesn't do sBIT below 8! */
- /* The following allows results to pass if they correspond to anything in the
- * transformed range [input-.5,input+.5]; this is is required because of the
- * way libpng treates the 16_TO_8 flag when building the gamma tables.
- *
- * TODO: review this
- */
- pm.use_input_precision_16to8 = 1U;
-
- /* Some default values (set the behavior for 'make check' here).
- * These values simply control the maximum error permitted in the gamma
- * transformations. The practial limits for human perception are described
- * below (the setting for maxpc16), however for 8 bit encodings it isn't
- * possible to meet the accepted capabilities of human vision - i.e. 8 bit
- * images can never be good enough, regardless of encoding.
- */
- pm.maxout8 = .1; /* Arithmetic error in *encoded* value */
- pm.maxabs8 = .00005; /* 1/20000 */
- pm.maxcalc8 = .004; /* +/-1 in 8 bits for compose errors */
- pm.maxpc8 = .499; /* I.e., .499% fractional error */
- pm.maxout16 = .499; /* Error in *encoded* value */
- pm.maxabs16 = .00005;/* 1/20000 */
- pm.maxcalc16 =.000015;/* +/-1 in 16 bits for compose errors */
-
- /* NOTE: this is a reasonable perceptual limit. We assume that humans can
- * perceive light level differences of 1% over a 100:1 range, so we need to
- * maintain 1 in 10000 accuracy (in linear light space), which is what the
- * following guarantees. It also allows significantly higher errors at
- * higher 16 bit values, which is important for performance. The actual
- * maximum 16 bit error is about +/-1.9 in the fixed point implementation but
- * this is only allowed for values >38149 by the following:
- */
- pm.maxpc16 = .005; /* I.e., 1/200% - 1/20000 */
-
- /* Now parse the command line options. */
- while (--argc >= 1)
- {
- int catmore = 0; /* Set if the argument has an argument. */
-
- /* Record each argument for posterity: */
- cp = safecat(command, sizeof command, cp, " ");
- cp = safecat(command, sizeof command, cp, *++argv);
-
- if (strcmp(*argv, "-v") == 0)
- pm.this.verbose = 1;
-
- else if (strcmp(*argv, "-l") == 0)
- pm.log = 1;
-
- else if (strcmp(*argv, "-q") == 0)
- summary = pm.this.verbose = pm.log = 0;
-
- else if (strcmp(*argv, "-w") == 0)
- pm.this.treat_warnings_as_errors = 0;
-
- else if (strcmp(*argv, "--speed") == 0)
- pm.this.speed = 1, pm.ngamma_tests = pm.ngammas, pm.test_standard = 0,
- summary = 0;
-
- else if (strcmp(*argv, "--memory") == 0)
- memstats = 1;
-
- else if (strcmp(*argv, "--size") == 0)
- pm.test_size = 1;
-
- else if (strcmp(*argv, "--nosize") == 0)
- pm.test_size = 0;
-
- else if (strcmp(*argv, "--standard") == 0)
- pm.test_standard = 1;
-
- else if (strcmp(*argv, "--nostandard") == 0)
- pm.test_standard = 0;
-
- else if (strcmp(*argv, "--transform") == 0)
- pm.test_transform = 1;
-
- else if (strcmp(*argv, "--notransform") == 0)
- pm.test_transform = 0;
-
-#ifdef PNG_READ_TRANSFORMS_SUPPORTED
- else if (strncmp(*argv, "--transform-disable=",
- sizeof "--transform-disable") == 0)
- {
- pm.test_transform = 1;
- transform_disable(*argv + sizeof "--transform-disable");
- }
-
- else if (strncmp(*argv, "--transform-enable=",
- sizeof "--transform-enable") == 0)
- {
- pm.test_transform = 1;
- transform_enable(*argv + sizeof "--transform-enable");
- }
-#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
-
- else if (strcmp(*argv, "--gamma") == 0)
- {
- /* Just do two gamma tests here (2.2 and linear) for speed: */
- pm.ngamma_tests = 2U;
- pm.test_gamma_threshold = 1;
- pm.test_gamma_transform = 1;
- pm.test_gamma_sbit = 1;
- pm.test_gamma_scale16 = 1;
- pm.test_gamma_background = 1;
- pm.test_gamma_alpha_mode = 1;
- }
-
- else if (strcmp(*argv, "--nogamma") == 0)
- pm.ngamma_tests = 0;
-
- else if (strcmp(*argv, "--gamma-threshold") == 0)
- pm.ngamma_tests = 2U, pm.test_gamma_threshold = 1;
-
- else if (strcmp(*argv, "--nogamma-threshold") == 0)
- pm.test_gamma_threshold = 0;
-
- else if (strcmp(*argv, "--gamma-transform") == 0)
- pm.ngamma_tests = 2U, pm.test_gamma_transform = 1;
-
- else if (strcmp(*argv, "--nogamma-transform") == 0)
- pm.test_gamma_transform = 0;
-
- else if (strcmp(*argv, "--gamma-sbit") == 0)
- pm.ngamma_tests = 2U, pm.test_gamma_sbit = 1;
-
- else if (strcmp(*argv, "--nogamma-sbit") == 0)
- pm.test_gamma_sbit = 0;
-
- else if (strcmp(*argv, "--gamma-16-to-8") == 0)
- pm.ngamma_tests = 2U, pm.test_gamma_scale16 = 1;
-
- else if (strcmp(*argv, "--nogamma-16-to-8") == 0)
- pm.test_gamma_scale16 = 0;
-
- else if (strcmp(*argv, "--gamma-background") == 0)
- pm.ngamma_tests = 2U, pm.test_gamma_background = 1;
-
- else if (strcmp(*argv, "--nogamma-background") == 0)
- pm.test_gamma_background = 0;
-
- else if (strcmp(*argv, "--gamma-alpha-mode") == 0)
- pm.ngamma_tests = 2U, pm.test_gamma_alpha_mode = 1;
-
- else if (strcmp(*argv, "--nogamma-alpha-mode") == 0)
- pm.test_gamma_alpha_mode = 0;
-
- else if (strcmp(*argv, "--expand16") == 0)
- pm.test_gamma_expand16 = 1;
-
- else if (strcmp(*argv, "--noexpand16") == 0)
- pm.test_gamma_expand16 = 0;
-
- else if (strcmp(*argv, "--more-gammas") == 0)
- pm.ngamma_tests = 3U;
-
- else if (strcmp(*argv, "--all-gammas") == 0)
- pm.ngamma_tests = pm.ngammas;
-
- else if (strcmp(*argv, "--progressive-read") == 0)
- pm.this.progressive = 1;
-
- else if (strcmp(*argv, "--use-update-info") == 0)
- ++pm.use_update_info; /* Can call multiple times */
-
- else if (strcmp(*argv, "--interlace") == 0)
- pm.interlace_type = PNG_INTERLACE_ADAM7;
-
- else if (strcmp(*argv, "--use-input-precision") == 0)
- pm.use_input_precision = 1;
-
- else if (strcmp(*argv, "--calculations-use-input-precision") == 0)
- pm.calculations_use_input_precision = 1;
-
- else if (strcmp(*argv, "--assume-16-bit-calculations") == 0)
- pm.assume_16_bit_calculations = 1;
-
- else if (strcmp(*argv, "--calculations-follow-bit-depth") == 0)
- pm.calculations_use_input_precision =
- pm.assume_16_bit_calculations = 0;
-
- else if (strcmp(*argv, "--exhaustive") == 0)
- pm.test_exhaustive = 1;
-
- else if (argc > 1 && strcmp(*argv, "--sbitlow") == 0)
- --argc, pm.sbitlow = (png_byte)atoi(*++argv), catmore = 1;
-
- else if (argc > 1 && strcmp(*argv, "--touch") == 0)
- --argc, touch = *++argv, catmore = 1;
-
- else if (argc > 1 && strncmp(*argv, "--max", 5) == 0)
- {
- --argc;
-
- if (strcmp(5+*argv, "abs8") == 0)
- pm.maxabs8 = atof(*++argv);
-
- else if (strcmp(5+*argv, "abs16") == 0)
- pm.maxabs16 = atof(*++argv);
-
- else if (strcmp(5+*argv, "calc8") == 0)
- pm.maxcalc8 = atof(*++argv);
-
- else if (strcmp(5+*argv, "calc16") == 0)
- pm.maxcalc16 = atof(*++argv);
-
- else if (strcmp(5+*argv, "out8") == 0)
- pm.maxout8 = atof(*++argv);
-
- else if (strcmp(5+*argv, "out16") == 0)
- pm.maxout16 = atof(*++argv);
-
- else if (strcmp(5+*argv, "pc8") == 0)
- pm.maxpc8 = atof(*++argv);
-
- else if (strcmp(5+*argv, "pc16") == 0)
- pm.maxpc16 = atof(*++argv);
-
- else
- {
- fprintf(stderr, "pngvalid: %s: unknown 'max' option\n", *argv);
- exit(1);
- }
-
- catmore = 1;
- }
-
- else if (strcmp(*argv, "--log8") == 0)
- --argc, pm.log8 = atof(*++argv), catmore = 1;
-
- else if (strcmp(*argv, "--log16") == 0)
- --argc, pm.log16 = atof(*++argv), catmore = 1;
-
- else
- {
- fprintf(stderr, "pngvalid: %s: unknown argument\n", *argv);
- exit(1);
- }
-
- if (catmore) /* consumed an extra *argv */
- {
- cp = safecat(command, sizeof command, cp, " ");
- cp = safecat(command, sizeof command, cp, *argv);
- }
- }
-
- /* If pngvalid is run with no arguments default to a reasonable set of the
- * tests.
- */
- if (pm.test_standard == 0 && pm.test_size == 0 && pm.test_transform == 0 &&
- pm.ngamma_tests == 0)
- {
- /* Make this do all the tests done in the test shell scripts with the same
- * parameters, where possible. The limitation is that all the progressive
- * read and interlace stuff has to be done in separate runs, so only the
- * basic 'standard' and 'size' tests are done.
- */
- pm.test_standard = 1;
- pm.test_size = 1;
- pm.test_transform = 1;
- pm.ngamma_tests = 2U;
- }
-
- if (pm.ngamma_tests > 0 &&
- pm.test_gamma_threshold == 0 && pm.test_gamma_transform == 0 &&
- pm.test_gamma_sbit == 0 && pm.test_gamma_scale16 == 0 &&
- pm.test_gamma_background == 0 && pm.test_gamma_alpha_mode == 0)
- {
- pm.test_gamma_threshold = 1;
- pm.test_gamma_transform = 1;
- pm.test_gamma_sbit = 1;
- pm.test_gamma_scale16 = 1;
- pm.test_gamma_background = 1;
- pm.test_gamma_alpha_mode = 1;
- }
-
- else if (pm.ngamma_tests == 0)
- {
- /* Nothing to test so turn everything off: */
- pm.test_gamma_threshold = 0;
- pm.test_gamma_transform = 0;
- pm.test_gamma_sbit = 0;
- pm.test_gamma_scale16 = 0;
- pm.test_gamma_background = 0;
- pm.test_gamma_alpha_mode = 0;
- }
-
- Try
- {
- /* Make useful base images */
- make_transform_images(&pm.this);
-
- /* Perform the standard and gamma tests. */
- if (pm.test_standard)
- {
- perform_interlace_macro_validation();
- perform_formatting_test(&pm.this);
- perform_standard_test(&pm);
- perform_error_test(&pm);
- }
-
- /* Various oddly sized images: */
- if (pm.test_size)
- {
- make_size_images(&pm.this);
- perform_size_test(&pm);
- }
-
-#ifdef PNG_READ_TRANSFORMS_SUPPORTED
- /* Combinatorial transforms: */
- if (pm.test_transform)
- perform_transform_test(&pm);
-#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
-
-#ifdef PNG_READ_GAMMA_SUPPORTED
- if (pm.ngamma_tests > 0)
- perform_gamma_test(&pm, summary);
-#endif
- }
-
- Catch(fault)
- {
- fprintf(stderr, "pngvalid: test aborted (probably failed in cleanup)\n");
- if (!pm.this.verbose)
- {
- if (pm.this.error[0] != 0)
- fprintf(stderr, "pngvalid: first error: %s\n", pm.this.error);
-
- fprintf(stderr, "pngvalid: run with -v to see what happened\n");
- }
- exit(1);
- }
-
- if (summary)
- {
- printf("%s: %s (%s point arithmetic)\n",
- (pm.this.nerrors || (pm.this.treat_warnings_as_errors &&
- pm.this.nwarnings)) ? "FAIL" : "PASS",
- command,
-#if defined(PNG_FLOATING_ARITHMETIC_SUPPORTED) || PNG_LIBPNG_VER < 10500
- "floating"
-#else
- "fixed"
-#endif
- );
- }
-
- if (memstats)
- {
- printf("Allocated memory statistics (in bytes):\n"
- "\tread %lu maximum single, %lu peak, %lu total\n"
- "\twrite %lu maximum single, %lu peak, %lu total\n",
- (unsigned long)pm.this.read_memory_pool.max_max,
- (unsigned long)pm.this.read_memory_pool.max_limit,
- (unsigned long)pm.this.read_memory_pool.max_total,
- (unsigned long)pm.this.write_memory_pool.max_max,
- (unsigned long)pm.this.write_memory_pool.max_limit,
- (unsigned long)pm.this.write_memory_pool.max_total);
- }
-
- /* Do this here to provoke memory corruption errors in memory not directly
- * allocated by libpng - not a complete test, but better than nothing.
- */
- store_delete(&pm.this);
-
- /* Error exit if there are any errors, and maybe if there are any
- * warnings.
- */
- if (pm.this.nerrors || (pm.this.treat_warnings_as_errors &&
- pm.this.nwarnings))
- {
- if (!pm.this.verbose)
- fprintf(stderr, "pngvalid: %s\n", pm.this.error);
-
- fprintf(stderr, "pngvalid: %d errors, %d warnings\n", pm.this.nerrors,
- pm.this.nwarnings);
-
- exit(1);
- }
-
- /* Success case. */
- if (touch != NULL)
- {
- FILE *fsuccess = fopen(touch, "wt");
-
- if (fsuccess != NULL)
- {
- int error = 0;
- fprintf(fsuccess, "PNG validation succeeded\n");
- fflush(fsuccess);
- error = ferror(fsuccess);
-
- if (fclose(fsuccess) || error)
- {
- fprintf(stderr, "%s: write failed\n", touch);
- exit(1);
- }
- }
- }
-
- return 0;
-}
diff -ru4NwbB libpng-1.5.6/pngwrite.c libpng-1.5.7/pngwrite.c
--- libpng-1.5.6/pngwrite.c 2011-11-02 22:42:50.547268135 -0500
+++ libpng-1.5.7/pngwrite.c 2011-12-15 09:45:32.592488881 -0600
@@ -1,8 +1,8 @@
/* pngwrite.c - general routines to write a PNG file
*
- * Last changed in libpng 1.5.6 [December 15, 2011]
+ * Last changed in libpng 1.5.7 [December 15, 2011]
* Copyright (c) 1998-2011 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
*
@@ -489,10 +489,11 @@
#endif
#ifdef PNG_SETJMP_SUPPORTED
/* Applications that neglect to set up their own setjmp() and then
- encounter a png_error() will longjmp here. Since the jmpbuf is
- then meaningless we abort instead of returning. */
+ * encounter a png_error() will longjmp here. Since the jmpbuf is
+ * then meaningless we abort instead of returning.
+ */
#ifdef USE_FAR_KEYWORD
if (setjmp(tmp_jmpbuf))
#else
if (setjmp(png_jmpbuf(png_ptr))) /* sets longjmp to match setjmp */
diff -ru4NwbB libpng-1.5.6/pngwtran.c libpng-1.5.7/pngwtran.c
--- libpng-1.5.6/pngwtran.c 2011-11-02 22:42:50.554047247 -0500
+++ libpng-1.5.7/pngwtran.c 2011-12-15 09:45:32.599378564 -0600
@@ -1,8 +1,8 @@
/* pngwtran.c - transforms the data in a row for PNG writers
*
- * Last changed in libpng 1.5.6 [December 15, 2011]
+ * Last changed in libpng 1.5.6 [November 3, 2011]
* Copyright (c) 1998-2011 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
*
diff -ru4NwbB libpng-1.5.6/pngwutil.c libpng-1.5.7/pngwutil.c
--- libpng-1.5.6/pngwutil.c 2011-11-02 22:42:50.567056497 -0500
+++ libpng-1.5.7/pngwutil.c 2011-12-15 09:45:32.612509914 -0600
@@ -1,8 +1,8 @@
/* pngwutil.c - utilities to write a PNG file
*
- * Last changed in libpng 1.5.6 [December 15, 2011]
+ * Last changed in libpng 1.5.6 [November 3, 2011]
* Copyright (c) 1998-2011 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
*
diff -ru4NwbB libpng-1.5.6/projects/owatcom/libpng.wpj libpng-1.5.7/projects/owatcom/libpng.wpj
--- libpng-1.5.6/projects/owatcom/libpng.wpj 2011-06-11 06:32:45.000000000 -0500
+++ libpng-1.5.7/projects/owatcom/libpng.wpj 2011-12-03 19:57:08.558182000 -0600
@@ -4,11 +4,11 @@
VpeMain
1
WRect
256
-146
-8966
-9303
+0
+8960
+9284
2
MProject
3
MCommand
@@ -46,10 +46,10 @@
10
WRect
0
0
-5644
-4183
+5632
+4164
0
0
11
WFileName
@@ -61,11 +61,11 @@
VComponent
13
WRect
1280
-1560
-5644
-4183
+1540
+5632
+4164
0
0
14
WFileName
@@ -76,12 +76,12 @@
15
VComponent
16
WRect
-530
-507
-5644
-4183
+518
+487
+5632
+4164
0
0
17
WFileName
diff -ru4NwbB libpng-1.5.6/projects/owatcom/pngconfig.mak libpng-1.5.7/projects/owatcom/pngconfig.mak
--- libpng-1.5.6/projects/owatcom/pngconfig.mak 2011-06-11 06:11:41.000000000 -0500
+++ libpng-1.5.7/projects/owatcom/pngconfig.mak 2011-12-03 19:57:08.574364000 -0600
@@ -56,11 +56,11 @@
instructions consult and edit projects/openwatcom/pngconfig.dfa
<<
$(DELETE) dfn.c dfn1.out dfn2.out
-pnglibconf.dfn: ..\..\scripts\pnglibconf.dfa ..\..\scripts\options.awk pngconfig.dfa
+pnglibconf.dfn: ..\..\scripts\pnglibconf.dfa ..\..\scripts\options.awk pngconfig.dfa ..\..\pngconf.h
$(DELETE) $@ dfn1.out dfn2.out
- $(AWK) -f ..\..\scripts\options.awk out=dfn1.out ..\..\scripts\pnglibconf.dfa pngconfig.dfa $(DFA_XTRA) 1>&2
+ $(AWK) -f ..\..\scripts\options.awk out=dfn1.out version=search ..\..\pngconf.h ..\..\scripts\pnglibconf.dfa pngconfig.dfa $(DFA_XTRA) 1>&2
$(AWK) -f ..\..\scripts\options.awk out=dfn2.out dfn1.out 1>&2
$(COPY) dfn2.out $@
$(DELETE) dfn1.out dfn2.out
diff -ru4NwbB libpng-1.5.6/projects/owatcom/pngvalid.tgt libpng-1.5.7/projects/owatcom/pngvalid.tgt
--- libpng-1.5.6/projects/owatcom/pngvalid.tgt 2011-06-11 06:11:41.000000000 -0500
+++ libpng-1.5.7/projects/owatcom/pngvalid.tgt 2011-12-03 19:57:08.608239000 -0600
@@ -191,10 +191,10 @@
1
0
47
MItem
-16
-..\..\pngvalid.c
+33
+..\..\contrib\libtests\pngvalid.c
48
WString
4
COBJ
diff -ru4NwbB libpng-1.5.6/projects/vstudio/pngvalid/pngvalid.vcxproj libpng-1.5.7/projects/vstudio/pngvalid/pngvalid.vcxproj
--- libpng-1.5.6/projects/vstudio/pngvalid/pngvalid.vcxproj 2011-11-02 22:42:52.845365823 -0500
+++ libpng-1.5.7/projects/vstudio/pngvalid/pngvalid.vcxproj 2011-12-15 09:45:34.967740823 -0600
@@ -203,16 +203,15 @@
<LinkTimeCodeGeneration>UseLinkTimeCodeGeneration</LinkTimeCodeGeneration>
</Link>
<CustomBuildStep>
<Message>Executing PNG validation program</Message>
- <Command>$(OutDir)pngvalid.exe ..\..\..\pngvalid.png $(IntDir)pngout.png</Command>
<Command>"$(OutDir)pngvalid.exe" --touch "$(IntDir)pngvalid.out"</Command>
<Outputs>$(IntDir)pngvalid.out</Outputs>
<Inputs>$(OutDir)pngvalid.exe</Inputs>
</CustomBuildStep>
</ItemDefinitionGroup>
<ItemGroup>
- <ClCompile Include="..\..\..\pngvalid.c" />
+ <ClCompile Include="..\..\..\contrib\libtests\pngvalid.c" />
</ItemGroup>
<Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
<ImportGroup Label="ExtensionTargets">
</ImportGroup>
diff -ru4NwbB libpng-1.5.6/projects/vstudio/vstudio.sln libpng-1.5.7/projects/vstudio/vstudio.sln
--- libpng-1.5.6/projects/vstudio/vstudio.sln 2010-08-24 15:04:11.000000000 -0500
+++ libpng-1.5.7/projects/vstudio/vstudio.sln 2011-11-23 09:00:02.985074000 -0600
@@ -1,24 +1,24 @@
Microsoft Visual Studio Solution File, Format Version 11.00
# Visual Studio 2010
Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "libpng", "libpng\libpng.vcxproj", "{D6973076-9317-4EF2-A0B8-B7A18AC0713E}"
ProjectSection(ProjectDependencies) = postProject
- {64CE4900-97EA-2DD5-4226-F2E36FFF2867} = {64CE4900-97EA-2DD5-4226-F2E36FFF2867}
+ {60F89955-91C6-3A36-8000-13C592FEC2DF} = {60F89955-91C6-3A36-8000-13C592FEC2DF}
{EB33566E-DA7F-4D28-9077-88C0B7C77E35} = {EB33566E-DA7F-4D28-9077-88C0B7C77E35}
EndProjectSection
EndProject
Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "pngtest", "pngtest\pngtest.vcxproj", "{228BA965-50D5-42B2-8BCF-AFCC227E3C1D}"
ProjectSection(ProjectDependencies) = postProject
- {64CE4900-97EA-2DD5-4226-F2E36FFF2867} = {64CE4900-97EA-2DD5-4226-F2E36FFF2867}
+ {60F89955-91C6-3A36-8000-13C592FEC2DF} = {60F89955-91C6-3A36-8000-13C592FEC2DF}
{EB33566E-DA7F-4D28-9077-88C0B7C77E35} = {EB33566E-DA7F-4D28-9077-88C0B7C77E35}
{D6973076-9317-4EF2-A0B8-B7A18AC0713E} = {D6973076-9317-4EF2-A0B8-B7A18AC0713E}
EndProjectSection
EndProject
-Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "zlib", "zlib\zlib.vcxproj", "{64CE4900-97EA-2DD5-4226-F2E36FFF2867}"
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "zlib", "zlib\zlib.vcxproj", "{60F89955-91C6-3A36-8000-13C592FEC2DF}"
EndProject
Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "pngvalid", "pngvalid\pngvalid.vcxproj", "{9B36B6FE-7FC0-434F-A71F-BBEF8099F1D8}"
ProjectSection(ProjectDependencies) = postProject
- {64CE4900-97EA-2DD5-4226-F2E36FFF2867} = {64CE4900-97EA-2DD5-4226-F2E36FFF2867}
+ {60F89955-91C6-3A36-8000-13C592FEC2DF} = {60F89955-91C6-3A36-8000-13C592FEC2DF}
{EB33566E-DA7F-4D28-9077-88C0B7C77E35} = {EB33566E-DA7F-4D28-9077-88C0B7C77E35}
{D6973076-9317-4EF2-A0B8-B7A18AC0713E} = {D6973076-9317-4EF2-A0B8-B7A18AC0713E}
EndProjectSection
EndProject
@@ -47,16 +47,16 @@
{228BA965-50D5-42B2-8BCF-AFCC227E3C1D}.Release Library|Win32.ActiveCfg = Release Library|Win32
{228BA965-50D5-42B2-8BCF-AFCC227E3C1D}.Release Library|Win32.Build.0 = Release Library|Win32
{228BA965-50D5-42B2-8BCF-AFCC227E3C1D}.Release|Win32.ActiveCfg = Release|Win32
{228BA965-50D5-42B2-8BCF-AFCC227E3C1D}.Release|Win32.Build.0 = Release|Win32
- {64CE4900-97EA-2DD5-4226-F2E36FFF2867}.Debug Library|Win32.ActiveCfg = Debug Library|Win32
- {64CE4900-97EA-2DD5-4226-F2E36FFF2867}.Debug Library|Win32.Build.0 = Debug Library|Win32
- {64CE4900-97EA-2DD5-4226-F2E36FFF2867}.Debug|Win32.ActiveCfg = Debug|Win32
- {64CE4900-97EA-2DD5-4226-F2E36FFF2867}.Debug|Win32.Build.0 = Debug|Win32
- {64CE4900-97EA-2DD5-4226-F2E36FFF2867}.Release Library|Win32.ActiveCfg = Release Library|Win32
- {64CE4900-97EA-2DD5-4226-F2E36FFF2867}.Release Library|Win32.Build.0 = Release Library|Win32
- {64CE4900-97EA-2DD5-4226-F2E36FFF2867}.Release|Win32.ActiveCfg = Release|Win32
- {64CE4900-97EA-2DD5-4226-F2E36FFF2867}.Release|Win32.Build.0 = Release|Win32
+ {60F89955-91C6-3A36-8000-13C592FEC2DF}.Debug Library|Win32.ActiveCfg = Debug Library|Win32
+ {60F89955-91C6-3A36-8000-13C592FEC2DF}.Debug Library|Win32.Build.0 = Debug Library|Win32
+ {60F89955-91C6-3A36-8000-13C592FEC2DF}.Debug|Win32.ActiveCfg = Debug|Win32
+ {60F89955-91C6-3A36-8000-13C592FEC2DF}.Debug|Win32.Build.0 = Debug|Win32
+ {60F89955-91C6-3A36-8000-13C592FEC2DF}.Release Library|Win32.ActiveCfg = Release Library|Win32
+ {60F89955-91C6-3A36-8000-13C592FEC2DF}.Release Library|Win32.Build.0 = Release Library|Win32
+ {60F89955-91C6-3A36-8000-13C592FEC2DF}.Release|Win32.ActiveCfg = Release|Win32
+ {60F89955-91C6-3A36-8000-13C592FEC2DF}.Release|Win32.Build.0 = Release|Win32
{9B36B6FE-7FC0-434F-A71F-BBEF8099F1D8}.Debug Library|Win32.ActiveCfg = Debug Library|Win32
{9B36B6FE-7FC0-434F-A71F-BBEF8099F1D8}.Debug Library|Win32.Build.0 = Debug Library|Win32
{9B36B6FE-7FC0-434F-A71F-BBEF8099F1D8}.Debug|Win32.ActiveCfg = Debug|Win32
{9B36B6FE-7FC0-434F-A71F-BBEF8099F1D8}.Debug|Win32.Build.0 = Debug|Win32
@@ -71,8 +71,16 @@
{EB33566E-DA7F-4D28-9077-88C0B7C77E35}.Release Library|Win32.ActiveCfg = Release|Win32
{EB33566E-DA7F-4D28-9077-88C0B7C77E35}.Release Library|Win32.Build.0 = Release|Win32
{EB33566E-DA7F-4D28-9077-88C0B7C77E35}.Release|Win32.ActiveCfg = Release|Win32
{EB33566E-DA7F-4D28-9077-88C0B7C77E35}.Release|Win32.Build.0 = Release|Win32
+ {277AC57F-313B-4D06-B119-A3CDB672D2FF}.Debug Library|Win32.ActiveCfg = Debug Library|Win32
+ {277AC57F-313B-4D06-B119-A3CDB672D2FF}.Debug Library|Win32.Build.0 = Debug Library|Win32
+ {277AC57F-313B-4D06-B119-A3CDB672D2FF}.Debug|Win32.ActiveCfg = Debug|Win32
+ {277AC57F-313B-4D06-B119-A3CDB672D2FF}.Debug|Win32.Build.0 = Debug|Win32
+ {277AC57F-313B-4D06-B119-A3CDB672D2FF}.Release Library|Win32.ActiveCfg = Release Library|Win32
+ {277AC57F-313B-4D06-B119-A3CDB672D2FF}.Release Library|Win32.Build.0 = Release Library|Win32
+ {277AC57F-313B-4D06-B119-A3CDB672D2FF}.Release|Win32.ActiveCfg = Release|Win32
+ {277AC57F-313B-4D06-B119-A3CDB672D2FF}.Release|Win32.Build.0 = Release|Win32
EndGlobalSection
GlobalSection(SolutionProperties) = preSolution
HideSolutionNode = FALSE
EndGlobalSection
diff -ru4NwbB libpng-1.5.6/scripts/def.dfn libpng-1.5.7/scripts/def.dfn
--- libpng-1.5.6/scripts/def.dfn 2011-01-04 09:45:35.000000000 -0600
+++ libpng-1.5.7/scripts/def.dfn 2011-11-03 16:13:57.945898000 -0500
@@ -26,13 +26,13 @@
S--E
S-EXPORTS-E
S-;Version 1.5.0beta58-E
-/* NOTE: @@@ is interpreted by the calling script as a signal to
+/* NOTE: PNG_JOIN is interpreted by the calling script as a signal to
* join the two things on either side, so we can do symbol
* substitution within the name, regular C ## joins the pp-tokens,
* not their final values.
*/
#define PNG_EXPORTA(ordinal, type, name, args, attributes)\
- PNG_DEFN_MAGIC- SYMBOL_PREFIX @@@ name-PNG_DEFN_END
+ PNG_DEFN_MAGIC- SYMBOL_PREFIX PNG_JOIN name-PNG_DEFN_END
#include "../png.h"
diff -ru4NwbB libpng-1.5.6/scripts/makefile.std libpng-1.5.7/scripts/makefile.std
--- libpng-1.5.6/scripts/makefile.std 2011-11-02 22:42:52.714325462 -0500
+++ libpng-1.5.7/scripts/makefile.std 2011-12-15 09:45:34.810974501 -0600
@@ -49,11 +49,11 @@
all: libpng.a pngtest
# The standard pnglibconf.h exists as scripts/pnglibconf.h.prebuilt,
# copy this if the following doesn't work.
-pnglibconf.dfn: scripts/pnglibconf.dfa scripts/options.awk
+pnglibconf.dfn: scripts/pnglibconf.dfa scripts/options.awk pngconf.h
$(RM_F) $@ dfn?.out
- $(AWK) -f scripts/options.awk out=dfn1.out\
+ $(AWK) -f scripts/options.awk out=dfn1.out version=search pngconf.h\
scripts/pnglibconf.dfa $(DFA_XTRA) 1>&2
$(AWK) -f scripts/options.awk out=dfn2.out dfn1.out 1>&2
cp dfn2.out $@
$(RM_F) dfn?.out
@@ -61,11 +61,11 @@
pnglibconf.h: pnglibconf.dfn
$(RM_F) $@ dfn.c dfn?.out
$(ECHO) '#include "pnglibconf.dfn"' >dfn.c
$(CPP) $(DFNFLAGS) dfn.c >dfn1.out
- $(SED) -n -e 's|^.*PNG_DEFN_MAGIC-\(.*\)-PNG_DEFN_END.*$$|\1|p'\
+ $(SED) -n -e 's|^.*PNG_DEFN_MAGIC *-\(.*\)- *PNG_DEFN_END.*$$|\1|p'\
dfn1.out >dfn2.out
- $(SED) -e 's| *@@@ *||g' -e 's| *$$||' dfn2.out >dfn3.out
+ $(SED) -e 's| *PNG_JOIN *||g' -e 's| *$$||' dfn2.out >dfn3.out
cp dfn3.out $@
$(RM_F) dfn.c dfn?.out
libpng.a: $(OBJS)
diff -ru4NwbB libpng-1.5.6/scripts/options.awk libpng-1.5.7/scripts/options.awk
--- libpng-1.5.6/scripts/options.awk 2011-05-07 10:30:44.000000000 -0500
+++ libpng-1.5.7/scripts/options.awk 2011-12-15 09:45:34.870841056 -0600
@@ -1,8 +1,8 @@
#!/bin/awk -f
# scripts/options.awk - library build configuration control
#
-# last changed in libpng version 1.5.0 - January 6, 2011
+# last changed in libpng version 1.5.7 - December 15, 2011
#
# Copyright (c) 1998-2011 Glenn Randers-Pehrson
#
# This code is released under the libpng license.
@@ -31,18 +31,21 @@
BEGIN{
out="/dev/null" # intermediate, preprocessed, file
pre=-1 # preprocess (first line)
+ version="libpng version unknown" # version information
+ version_file="" # where to find the version
err=0 # in-line exit sets this
start="PNG_DEFN_MAGIC-" # Arbitrary start
end="-PNG_DEFN_END" # Arbitrary end
- cx= "/@@@*" # Open C comment for output file
+ ct="PNG_JOIN" # Join two tokens
+ cx= "/" ct "*" # Open C comment for output file
comment=start cx # Comment start
cend="*/" end # Comment end
- def=start "#define PNG_@@@" # Arbitrary define
- sup="@@@_SUPPORTED" end # end supported option
- und=comment "#undef PNG_@@@" # Unsupported option
- une="@@@_SUPPORTED" cend # end unsupported option
+ def=start "#define PNG_" ct # Arbitrary define
+ sup=ct "_SUPPORTED" end # end supported option
+ und=comment "#undef PNG_" ct # Unsupported option
+ une=ct "_SUPPORTED" cend # end unsupported option
error=start "ERROR:" # error message
# Variables
deb=0 # debug - set on command line
@@ -84,8 +87,30 @@
# And fall through to continue processing
}
}
+# While pre-processing if version is set to "search" look for a version string
+# in the following file.
+pre && version == "search" && version_file == ""{
+ version_file = FILENAME
+}
+
+pre && version == "search" && version_file != FILENAME{
+ print "version string not found in", version_file
+ err = 1
+ exit 1
+}
+
+pre && version == "search" && $0 ~ /^ \* libpng version/{
+ version = substr($0, 4)
+ print "version =", version >out
+ next
+}
+
+pre && FILENAME == version_file{
+ next
+}
+
# variable=value
# Sets the given variable to the given value (the syntax is fairly
# free form, except for deb (you are expected to understand how to
# set the debug variable...)
@@ -93,8 +118,13 @@
# This happens before the check on 'pre' below skips most of the
# rest of the actions, so the variable settings happen during
# preprocessing but are recorded in the END action too. This
# allows them to be set on the command line too.
+$0 ~ /^[ ]*version[ ]*=/{
+ sub(/^[ ]*version[ ]*=[ ]*/, "")
+ version = $0
+ next
+}
$0 ~ /^[ ]*everything[ =]*off[ ]*$/{
everything = "off"
next
}
@@ -164,8 +194,21 @@
print start end >out
next
}
+# version
+# Inserts a version comment
+$1 == "version" && NF == 1{
+ if (version == "") {
+ print "ERROR: no version string set"
+ err = 1 # prevent END{} running
+ exit 1
+ }
+
+ print comment, version, cend >out
+ next
+}
+
# file output input protect
# Informational: the official name of the input file (without
# make generated local directories), the official name of the
# output file and, if required, a name to use in a protection
diff -ru4NwbB libpng-1.5.6/scripts/pnglibconf.dfa libpng-1.5.7/scripts/pnglibconf.dfa
--- libpng-1.5.6/scripts/pnglibconf.dfa 2011-10-13 19:32:21.681776000 -0500
+++ libpng-1.5.7/scripts/pnglibconf.dfa 2011-12-05 14:22:38.225250000 -0600
@@ -5,9 +5,9 @@
@ */
#
com pnglibconf.h - library build configuration
com
-com libpng version 1.5.3 - July 7, 2011
+version
com
com Copyright (c) 1998-2011 Glenn Randers-Pehrson
com
com This code is released under the libpng license.
@@ -295,9 +295,9 @@
# forces them to be chopped down to 8-bit, and disables any 16-bit
# processing after that has happened. You need to be sure to enable
# READ_SCALE_16_TO_8 or READ_STRIP_16_TO_8 when you disable READ_16BIT for
# this to work properly. You should disable the other option if you need to
-# ensure a particular convertion (otherwise the app can chose.)
+# ensure a particular conversion (otherwise the app can chose.)
option READ_16BIT requires READ enables 16BIT
option READ_QUANTIZE requires READ
diff -ru4NwbB libpng-1.5.6/scripts/pnglibconf.h.prebuilt libpng-1.5.7/scripts/pnglibconf.h.prebuilt
--- libpng-1.5.6/scripts/pnglibconf.h.prebuilt 2011-10-13 19:32:27.985999000 -0500
+++ libpng-1.5.7/scripts/pnglibconf.h.prebuilt 2011-12-15 09:45:34.882305764 -0600
@@ -2,9 +2,9 @@
/* libpng STANDARD API DEFINITION */
/* pnglibconf.h - library build configuration */
-/* libpng version 1.5.4 - last changed on June 22, 2011 */
+/* Libpng 1.5.7 - December 15, 2011 */
/* Copyright (c) 1998-2011 Glenn Randers-Pehrson */
/* This code is released under the libpng license. */
@@ -53,8 +53,10 @@
#define PNG_ERROR_TEXT_SUPPORTED
#define PNG_FIXED_POINT_SUPPORTED
#define PNG_FLOATING_ARITHMETIC_SUPPORTED
#define PNG_FLOATING_POINT_SUPPORTED
+#define PNG_FORMAT_AFIRST_SUPPORTED
+#define PNG_FORMAT_BGR_SUPPORTED
#define PNG_gAMA_SUPPORTED
#define PNG_HANDLE_AS_UNKNOWN_SUPPORTED
#define PNG_hIST_SUPPORTED
#define PNG_iCCP_SUPPORTED
diff -ru4NwbB libpng-1.5.6/scripts/pnglibconf.mak libpng-1.5.7/scripts/pnglibconf.mak
--- libpng-1.5.6/scripts/pnglibconf.mak 2011-05-07 10:31:01.000000000 -0500
+++ libpng-1.5.7/scripts/pnglibconf.mak 2011-11-08 19:12:49.536424000 -0600
@@ -34,20 +34,21 @@
$(DELETE) $@ dfn.c dfn1.out dfn2.out dfn3.out
$(ECHO) '#include "pnglibconf.dfn"' >dfn.c
$(CPP) $(DFNFLAGS) dfn.c >dfn1.out
$(ECHO) "If 'cpp -e' crashes try /lib/cpp (e.g. CPP='/lib/cpp')" >&2
- $(SED) -n -e 's|^.*PNG_DEFN_MAGIC-\(.*\)-PNG_DEFN_END.*$$|\1|p'\
+ $(SED) -n -e 's|^.*PNG_DEFN_MAGIC *-\(.*\)- *PNG_DEFN_END.*$$|\1|p'\
dfn1.out >dfn2.out
- $(SED) -e 's| *@@@ *||g' -e 's| *$$||' dfn2.out >dfn3.out
+ $(SED) -e 's| *PNG_JOIN *||g' -e 's| *$$||' dfn2.out >dfn3.out
$(COPY) dfn3.out $@
$(DELETE) dfn.c dfn1.out dfn2.out dfn3.out
-pnglibconf.dfn: $(srcdir)/scripts/pnglibconf.dfa $(srcdir)/scripts/options.awk
+pnglibconf.dfn: $(srcdir)/scripts/pnglibconf.dfa $(srcdir)/scripts/options.awk $(srcdir)/pngconf.h
$(DELETE) $@ dfn1.out dfn2.out
$(ECHO) "Calling $(AWK) from scripts/pnglibconf.mak" >&2
$(ECHO) "If 'awk' crashes try a better awk (e.g. AWK='nawk')" >&2
- $(AWK) -f $(srcdir)/scripts/options.awk out=dfn1.out\
- $(srcdir)/scripts/pnglibconf.dfa $(DFA_XTRA) 1>&2
+ $(AWK) -f $(srcdir)/scripts/options.awk out=dfn1.out version=search\
+ $(srcdir)/pngconf.h $(srcdir)/scripts/pnglibconf.dfa\
+ $(DFA_XTRA) 1>&2
$(AWK) -f $(srcdir)/scripts/options.awk out=dfn2.out dfn1.out 1>&2
$(COPY) dfn2.out $@
$(DELETE) dfn1.out dfn2.out
diff -ru4NwbB libpng-1.5.6/scripts/sym.dfn libpng-1.5.7/scripts/sym.dfn
--- libpng-1.5.6/scripts/sym.dfn 2011-01-21 19:20:38.000000000 -0600
+++ libpng-1.5.7/scripts/sym.dfn 2011-11-03 16:13:57.962584000 -0500
@@ -9,7 +9,7 @@
* and license in png.h
*/
#define PNG_EXPORTA(ordinal, type, name, args, attributes)\
- PNG_DEFN_MAGIC-SYMBOL_PREFIX @@@ name-PNG_DEFN_END
+ PNG_DEFN_MAGIC-SYMBOL_PREFIX PNG_JOIN name-PNG_DEFN_END
#include "../png.h"
diff -ru4NwbB libpng-1.5.6/scripts/vers.dfn libpng-1.5.7/scripts/vers.dfn
--- libpng-1.5.6/scripts/vers.dfn 2011-01-21 19:20:50.000000000 -0600
+++ libpng-1.5.7/scripts/vers.dfn 2011-11-03 16:13:57.969672000 -0500
@@ -10,15 +10,15 @@
*/
#define HEADER PNG_DEFN_MAGIC-PNGLIB_LIBNAME {global:-PNG_DEFN_END
-/* NOTE: @@@ is interpreted by the calling script as a signal to
+/* NOTE: PNG_JOIN is interpreted by the calling script as a signal to
* join the two things on either side, so we can do symbol
* substitution within the name, regular C ## joins the pp-tokens,
* not their final values.
*/
#define PNG_EXPORTA(ordinal, type, name, args, attributes)\
- PNG_DEFN_MAGIC- SYMBOL_PREFIX @@@ name;-PNG_DEFN_END
+ PNG_DEFN_MAGIC- SYMBOL_PREFIX PNG_JOIN name;-PNG_DEFN_END
#define TRAILER PNG_DEFN_MAGIC-local: *; };-PNG_DEFN_END
HEADER