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Diffstat (limited to 'libpng/contrib/libtests/pngvalid.c')
| -rw-r--r-- | libpng/contrib/libtests/pngvalid.c | 12230 |
1 files changed, 12230 insertions, 0 deletions
diff --git a/libpng/contrib/libtests/pngvalid.c b/libpng/contrib/libtests/pngvalid.c new file mode 100644 index 00000000..4dc4f844 --- /dev/null +++ b/libpng/contrib/libtests/pngvalid.c @@ -0,0 +1,12230 @@ + +/* pngvalid.c - validate libpng by constructing then reading png files. + * + * Last changed in libpng 1.6.31 [July 27, 2017] + * Copyright (c) 2014-2017 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> +#include <stdio.h> + +#if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H) +# include <config.h> +#endif + +#ifdef HAVE_FEENABLEEXCEPT /* from config.h, if included */ +# include <fenv.h> +#endif + +#ifndef FE_DIVBYZERO +# define FE_DIVBYZERO 0 +#endif +#ifndef FE_INVALID +# define FE_INVALID 0 +#endif +#ifndef FE_OVERFLOW +# define FE_OVERFLOW 0 +#endif + +/* Define the following to use this test against your installed libpng, rather + * than the one being built here: + */ +#ifdef PNG_FREESTANDING_TESTS +# include <png.h> +#else +# include "../../png.h" +#endif + +#ifdef PNG_ZLIB_HEADER +# include PNG_ZLIB_HEADER +#else +# include <zlib.h> /* For crc32 */ +#endif + +/* 1.6.1 added support for the configure test harness, which uses 77 to indicate + * a skipped test, in earlier versions we need to succeed on a skipped test, so: + */ +#if PNG_LIBPNG_VER >= 10601 && defined(HAVE_CONFIG_H) +# define SKIP 77 +#else +# define SKIP 0 +#endif + +/* pngvalid requires write support and one of the fixed or floating point APIs. + */ +#if defined(PNG_WRITE_SUPPORTED) &&\ + (defined(PNG_FIXED_POINT_SUPPORTED) || defined(PNG_FLOATING_POINT_SUPPORTED)) + +#if PNG_LIBPNG_VER < 10500 +/* This deliberately lacks the 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 + +#if PNG_LIBPNG_VER < 10600 + /* 1.6.0 constifies many APIs, the following exists to allow pngvalid to be + * compiled against earlier versions. + */ +# define png_const_structp png_structp +#endif + +#ifndef RELEASE_BUILD + /* RELEASE_BUILD is true for releases and release candidates: */ +# define RELEASE_BUILD (PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC) +#endif +#if RELEASE_BUILD +# define debugonly(something) +#else /* !RELEASE_BUILD */ +# define debugonly(something) something +#endif /* !RELEASE_BUILD */ + +#include <float.h> /* For floating point constants */ +#include <stdlib.h> /* For malloc */ +#include <string.h> /* For memcpy, memset */ +#include <math.h> /* For floor */ + +/* 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) + +/* 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 *****************************/ +#ifdef PNG_FREESTANDING_TESTS +# include <cexcept.h> +#else +# include "../visupng/cexcept.h" +#endif + +#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 + +/* This macro returns the number of elements in an array as an (unsigned int), + * it is necessary to avoid the inability of certain versions of GCC to use + * the value of a compile-time constant when performing range checks. It must + * be passed an array name. + */ +#define ARRAY_SIZE(a) ((unsigned int)((sizeof (a))/(sizeof (a)[0]))) + +/* GCC BUG 66447 (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66447) requires + * some broken GCC versions to be fixed up to avoid invalid whining about auto + * variables that are *not* changed within the scope of a setjmp being changed. + * + * Feel free to extend the list of broken versions. + */ +#define is_gnu(major,minor)\ + (defined __GNUC__) && __GNUC__ == (major) && __GNUC_MINOR__ == (minor) +#define is_gnu_patch(major,minor,patch)\ + is_gnu(major,minor) && __GNUC_PATCHLEVEL__ == 0 +/* For the moment just do it always; all versions of GCC seem to be broken: */ +#ifdef __GNUC__ + const void * volatile make_volatile_for_gnu; +# define gnu_volatile(x) make_volatile_for_gnu = &x; +#else /* !GNUC broken versions */ +# define gnu_volatile(x) +#endif /* !GNUC broken versions */ + +/******************************* 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, + 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 const char invalid[] = "invalid"; +static const char sep[] = ": "; + +static const char *colour_types[8] = +{ + "grayscale", invalid, "truecolour", "indexed-colour", + "grayscale with alpha", invalid, "truecolour with alpha", invalid +}; + +#ifdef PNG_READ_TRANSFORMS_SUPPORTED +/* 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; +} +#endif /* PNG_READ_SUPPORTED */ + +/* 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" (Pseudo-Random Bit Sequences and Noise + * Generation.) + */ +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); +} + +#if defined PNG_READ_SUPPORTED || defined PNG_WRITE_tRNS_SUPPORTED ||\ + defined PNG_WRITE_FILTER_SUPPORTED +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 R8(this) randomize(&(this), sizeof (this)) + +#ifdef PNG_READ_SUPPORTED +static png_byte +random_byte(void) +{ + unsigned char b1[1]; + randomize(b1, sizeof b1); + return b1[0]; +} +#endif /* READ */ + +static png_uint_16 +random_u16(void) +{ + unsigned char b2[2]; + randomize(b2, sizeof b2); + return png_get_uint_16(b2); +} + +#if defined PNG_READ_RGB_TO_GRAY_SUPPORTED ||\ + defined PNG_READ_FILLER_SUPPORTED +static png_uint_32 +random_u32(void) +{ + unsigned char b4[4]; + randomize(b4, sizeof b4); + return png_get_uint_32(b4); +} +#endif /* READ_FILLER || READ_RGB_TO_GRAY */ + +#endif /* READ || WRITE_tRNS || WRITE_FILTER */ + +#if defined PNG_READ_TRANSFORMS_SUPPORTED ||\ + defined PNG_WRITE_FILTER_SUPPORTED +static unsigned int +random_mod(unsigned int max) +{ + return random_u16() % max; /* 0 .. max-1 */ +} +#endif /* READ_TRANSFORMS || WRITE_FILTER */ + +#if (defined PNG_READ_RGB_TO_GRAY_SUPPORTED) ||\ + (defined PNG_READ_FILLER_SUPPORTED) +static int +random_choice(void) +{ + return random_byte() & 1; +} +#endif /* READ_RGB_TO_GRAY || READ_FILLER */ + +/* 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 otherwise a boolean + * indicating if a tRNS chunk was generated. + */ +#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) (((id) >> 8) & 0x1f) +#define INTERLACE_FROM_ID(id) ((png_byte)(((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, unsigned 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 (colour_type == 3) /* must have a palette */ + { + pos = safecat(buffer, bufsize, pos, "["); + pos = safecatn(buffer, bufsize, pos, npalette); + pos = safecat(buffer, bufsize, pos, "]"); + } + + else if (npalette != 0) + pos = safecat(buffer, bufsize, pos, "+tRNS"); + + 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 ? 1U : 16U) + +static int +next_format(png_bytep colour_type, png_bytep bit_depth, + unsigned int* palette_number, int low_depth_gray, int tRNS) +{ + if (*bit_depth == 0) + { + *colour_type = 0; + if (low_depth_gray) + *bit_depth = 1; + else + *bit_depth = 8; + *palette_number = 0; + return 1; + } + + if (*colour_type < 4/*no alpha channel*/) + { + /* Add multiple palettes for colour type 3, one image with tRNS + * and one without for other non-alpha formats: + */ + unsigned int pn = ++*palette_number; + png_byte ct = *colour_type; + + if (((ct == 0/*GRAY*/ || ct/*RGB*/ == 2) && tRNS && pn < 2) || + (ct == 3/*PALETTE*/ && pn < PALETTE_COUNT(*bit_depth))) + return 1; + + /* No: next bit depth */ + *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, int swap16, int littleendian) +{ + 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) + { + if (swap16) + return (*++row << 8) + result; + else + return (result << 8) + *++row; + } + + /* Less than 8 bits per sample. By default PNG has the big end of + * the egg on the left of the screen, but if littleendian is set + * then the big end is on the right. + */ + bit_index &= 7; + + if (!littleendian) + bit_index = 8-bit_index-bit_depth; + + return (result >> bit_index) & ((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, + int littleendian) +{ + /* 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) << + (littleendian ? toIndex&7 : 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 (littleendian) + { + if (fromIndex > 0) sourceByte >>= fromIndex; + if ((toIndex & 7) > 0) sourceByte <<= toIndex & 7; + } + + else + { + 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); +} + +#ifdef PNG_READ_SUPPORTED +/* 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, + int littleendian) +{ + memcpy(toBuffer, fromBuffer, bitWidth >> 3); + + if ((bitWidth & 7) != 0) + { + unsigned int mask; + + toBuffer += bitWidth >> 3; + fromBuffer += bitWidth >> 3; + if (littleendian) + mask = 0xff << (bitWidth & 7); + else + 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; + } +} +#endif /* PNG_READ_SUPPORTED */ + +/*************************** 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]; + unsigned int IDAT_bits; /* Number of bits in IDAT size */ + png_uint_32 IDAT_size; /* Total size of IDAT data */ + 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; + int noptions; /* number of options below: */ + struct { + unsigned char option; /* option number, 0..30 */ + unsigned char setting; /* setting (unset,invalid,on,off) */ + } options[16]; + char test[128]; /* Name of test */ + char error[256]; + + /* Share fields */ + png_uint_32 chunklen; /* Length of chunk+overhead (chunkpos >= 8) */ + png_uint_32 chunktype;/* Type of chunk (valid if chunkpos >= 4) */ + png_uint_32 chunkpos; /* Position in chunk */ + png_uint_32 IDAT_size;/* Accumulated IDAT size in .new */ + unsigned int IDAT_bits;/* Cache of the file store value */ + + /* 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) */ + uLong IDAT_crc; + png_uint_32 IDAT_len; /* Used when re-chunking IDAT chunks */ + png_uint_32 IDAT_pos; /* Used when re-chunking IDAT chunks */ + 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); +} + +#ifdef PNG_READ_TRANSFORMS_SUPPORTED +/* 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; + } +} +#endif /* PNG_READ_SUPPORTED */ + +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->chunkpos = 8; + ps->chunktype = 0; + ps->chunklen = 16; + ps->IDAT_size = 0; + ps->IDAT_bits = 0; + ps->new.prev = NULL; + ps->palette = NULL; + ps->npalette = 0; + ps->noptions = 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; + ps->chunkpos = 8; + ps->chunktype = 0; + ps->chunklen = 16; + ps->IDAT_size = 0; + ps->IDAT_bits = 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; + + 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; + } +} + +static unsigned int +bits_of(png_uint_32 num) +{ + /* Return the number of bits in 'num' */ + unsigned int b = 0; + + if (num & 0xffff0000U) b += 16U, num >>= 16; + if (num & 0xff00U) b += 8U, num >>= 8; + if (num & 0xf0U) b += 4U, num >>= 4; + if (num & 0xcU) b += 2U, num >>= 2; + if (num & 0x2U) ++b, num >>= 1; + if (num) ++b; + + return b; /* 0..32 */ +} + +/* 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; + + if (ps->chunkpos != 0U || ps->chunktype != 0U || ps->chunklen != 0U || + ps->IDAT_size == 0) + png_error(ps->pwrite, "storefile: incomplete write"); + + 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; + pf->IDAT_size = ps->IDAT_size; + pf->IDAT_bits = bits_of(ps->IDAT_size); + /* Because the IDAT always has zlib header stuff this must be true: */ + if (pf->IDAT_bits == 0U) + png_error(ps->pwrite, "storefile: 0 sized IDAT"); + ps->new.prev = NULL; + ps->writepos = 0; + ps->chunkpos = 8; + ps->chunktype = 0; + ps->chunklen = 16; + ps->IDAT_size = 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_const_structp pp, char *buffer, size_t bufsize, + size_t pos, 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_const_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_const_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); +} + +#ifdef PNG_READ_SUPPORTED +/* 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; + } +} +#endif /* PNG_READ_SUPPORTED */ + +/* Functions to use as PNG callbacks. */ +static void PNGCBAPI +store_error(png_structp ppIn, png_const_charp message) /* PNG_NORETURN */ +{ + png_const_structp pp = ppIn; + 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 PNGCBAPI +store_warning(png_structp ppIn, png_const_charp message) +{ + png_const_structp pp = ppIn; + 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(const png_store* ps, png_const_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_const_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_const_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; + } + } +} + +#ifdef PNG_READ_SUPPORTED +static void +store_image_check(const png_store* ps, png_const_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 */ + + for (; rows > 0; --rows) + { + 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; + } + } +} +#endif /* PNG_READ_SUPPORTED */ + +static int +valid_chunktype(png_uint_32 chunktype) +{ + /* Each byte in the chunk type must be in one of the ranges 65..90, 97..122 + * (both inclusive), so: + */ + unsigned int i; + + for (i=0; i<4; ++i) + { + unsigned int c = chunktype & 0xffU; + + if (!((c >= 65U && c <= 90U) || (c >= 97U && c <= 122U))) + return 0; + + chunktype >>= 8; + } + + return 1; /* It's valid */ +} + +static void PNGCBAPI +store_write(png_structp ppIn, png_bytep pb, png_size_t st) +{ + png_const_structp pp = ppIn; + png_store *ps = voidcast(png_store*, png_get_io_ptr(pp)); + size_t writepos = ps->writepos; + png_uint_32 chunkpos = ps->chunkpos; + png_uint_32 chunktype = ps->chunktype; + png_uint_32 chunklen = ps->chunklen; + + if (ps->pwrite != pp) + png_error(pp, "store state damaged"); + + /* Technically this is legal, but in practice libpng never writes more than + * the maximum chunk size at once so if it happens something weird has + * changed inside libpng (probably). + */ + if (st > 0x7fffffffU) + png_error(pp, "unexpected write size"); + + /* Now process the bytes to be written. Do this in units of the space in the + * output (write) buffer or, at the start 4 bytes for the chunk type and + * length limited in any case by the amount of data. + */ + while (st > 0) + { + if (writepos >= STORE_BUFFER_SIZE) + store_storenew(ps), writepos = 0; + + if (chunkpos < 4) + { + png_byte b = *pb++; + --st; + chunklen = (chunklen << 8) + b; + ps->new.buffer[writepos++] = b; + ++chunkpos; + } + + else if (chunkpos < 8) + { + png_byte b = *pb++; + --st; + chunktype = (chunktype << 8) + b; + ps->new.buffer[writepos++] = b; + + if (++chunkpos == 8) + { + chunklen &= 0xffffffffU; + if (chunklen > 0x7fffffffU) + png_error(pp, "chunk length too great"); + + chunktype &= 0xffffffffU; + if (chunktype == CHUNK_IDAT) + { + if (chunklen > ~ps->IDAT_size) + png_error(pp, "pngvalid internal image too large"); + + ps->IDAT_size += chunklen; + } + + else if (!valid_chunktype(chunktype)) + png_error(pp, "invalid chunk type"); + + chunklen += 12; /* for header and CRC */ + } + } + + else /* chunkpos >= 8 */ + { + png_size_t cb = st; + + if (cb > STORE_BUFFER_SIZE - writepos) + cb = STORE_BUFFER_SIZE - writepos; + + if (cb > chunklen - chunkpos/* bytes left in chunk*/) + cb = (png_size_t)/*SAFE*/(chunklen - chunkpos); + + memcpy(ps->new.buffer + writepos, pb, cb); + chunkpos += (png_uint_32)/*SAFE*/cb; + pb += cb; + writepos += cb; + st -= cb; + + if (chunkpos >= chunklen) /* must be equal */ + chunkpos = chunktype = chunklen = 0; + } + } /* while (st > 0) */ + + ps->writepos = writepos; + ps->chunkpos = chunkpos; + ps->chunktype = chunktype; + ps->chunklen = chunklen; +} + +static void PNGCBAPI +store_flush(png_structp ppIn) +{ + UNUSED(ppIn) /*DOES NOTHING*/ +} + +#ifdef PNG_READ_SUPPORTED +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; +} + +/* 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; +} + +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 png_size_t +store_read_chunk(png_store *ps, png_bytep pb, const png_size_t max, + const png_size_t min) +{ + png_uint_32 chunklen = ps->chunklen; + png_uint_32 chunktype = ps->chunktype; + png_uint_32 chunkpos = ps->chunkpos; + png_size_t st = max; + + if (st > 0) do + { + if (chunkpos >= chunklen) /* end of last chunk */ + { + png_byte buffer[8]; + + /* Read the header of the next chunk: */ + store_read_imp(ps, buffer, 8U); + chunklen = png_get_uint_32(buffer) + 12U; + chunktype = png_get_uint_32(buffer+4U); + chunkpos = 0U; /* Position read so far */ + } + + if (chunktype == CHUNK_IDAT) + { + png_uint_32 IDAT_pos = ps->IDAT_pos; + png_uint_32 IDAT_len = ps->IDAT_len; + png_uint_32 IDAT_size = ps->IDAT_size; + + /* The IDAT headers are constructed here; skip the input header. */ + if (chunkpos < 8U) + chunkpos = 8U; + + if (IDAT_pos == IDAT_len) + { + png_byte random = random_byte(); + + /* Make a new IDAT chunk, if IDAT_len is 0 this is the first IDAT, + * if IDAT_size is 0 this is the end. At present this is set up + * using a random number so that there is a 25% chance before + * the start of the first IDAT chunk being 0 length. + */ + if (IDAT_len == 0U) /* First IDAT */ + { + switch (random & 3U) + { + case 0U: IDAT_len = 12U; break; /* 0 bytes */ + case 1U: IDAT_len = 13U; break; /* 1 byte */ + default: IDAT_len = random_u32(); + IDAT_len %= IDAT_size; + IDAT_len += 13U; /* 1..IDAT_size bytes */ + break; + } + } + + else if (IDAT_size == 0U) /* all IDAT data read */ + { + /* The last (IDAT) chunk should be positioned at the CRC now: */ + if (chunkpos != chunklen-4U) + png_error(ps->pread, "internal: IDAT size mismatch"); + + /* The only option here is to add a zero length IDAT, this + * happens 25% of the time. Because of the check above + * chunklen-4U-chunkpos must be zero, we just need to skip the + * CRC now. + */ + if ((random & 3U) == 0U) + IDAT_len = 12U; /* Output another 0 length IDAT */ + + else + { + /* End of IDATs, skip the CRC to make the code above load the + * next chunk header next time round. + */ + png_byte buffer[4]; + + store_read_imp(ps, buffer, 4U); + chunkpos += 4U; + ps->IDAT_pos = IDAT_pos; + ps->IDAT_len = IDAT_len; + ps->IDAT_size = 0U; + continue; /* Read the next chunk */ + } + } + + else + { + /* Middle of IDATs, use 'random' to determine the number of bits + * to use in the IDAT length. + */ + IDAT_len = random_u32(); + IDAT_len &= (1U << (1U + random % ps->IDAT_bits)) - 1U; + if (IDAT_len > IDAT_size) + IDAT_len = IDAT_size; + IDAT_len += 12U; /* zero bytes may occur */ + } + + IDAT_pos = 0U; + ps->IDAT_crc = 0x35af061e; /* Ie: crc32(0UL, "IDAT", 4) */ + } /* IDAT_pos == IDAT_len */ + + if (IDAT_pos < 8U) /* Return the header */ do + { + png_uint_32 b; + unsigned int shift; + + if (IDAT_pos < 4U) + b = IDAT_len - 12U; + + else + b = CHUNK_IDAT; + + shift = 3U & IDAT_pos; + ++IDAT_pos; + + if (shift < 3U) + b >>= 8U*(3U-shift); + + *pb++ = 0xffU & b; + } + while (--st > 0 && IDAT_pos < 8); + + else if (IDAT_pos < IDAT_len - 4U) /* I.e not the CRC */ + { + if (chunkpos < chunklen-4U) + { + uInt avail = (uInt)-1; + + if (avail > (IDAT_len-4U) - IDAT_pos) + avail = (uInt)/*SAFE*/((IDAT_len-4U) - IDAT_pos); + + if (avail > st) + avail = (uInt)/*SAFE*/st; + + if (avail > (chunklen-4U) - chunkpos) + avail = (uInt)/*SAFE*/((chunklen-4U) - chunkpos); + + store_read_imp(ps, pb, avail); + ps->IDAT_crc = crc32(ps->IDAT_crc, pb, avail); + pb += (png_size_t)/*SAFE*/avail; + st -= (png_size_t)/*SAFE*/avail; + chunkpos += (png_uint_32)/*SAFE*/avail; + IDAT_size -= (png_uint_32)/*SAFE*/avail; + IDAT_pos += (png_uint_32)/*SAFE*/avail; + } + + else /* skip the input CRC */ + { + png_byte buffer[4]; + + store_read_imp(ps, buffer, 4U); + chunkpos += 4U; + } + } + + else /* IDAT crc */ do + { + uLong b = ps->IDAT_crc; + unsigned int shift = (IDAT_len - IDAT_pos); /* 4..1 */ + ++IDAT_pos; + + if (shift > 1U) + b >>= 8U*(shift-1U); + + *pb++ = 0xffU & b; + } + while (--st > 0 && IDAT_pos < IDAT_len); + + ps->IDAT_pos = IDAT_pos; + ps->IDAT_len = IDAT_len; + ps->IDAT_size = IDAT_size; + } + + else /* !IDAT */ + { + /* If there is still some pending IDAT data after the IDAT chunks have + * been processed there is a problem: + */ + if (ps->IDAT_len > 0 && ps->IDAT_size > 0) + png_error(ps->pread, "internal: missing IDAT data"); + + if (chunktype == CHUNK_IEND && ps->IDAT_len == 0U) + png_error(ps->pread, "internal: missing IDAT"); + + if (chunkpos < 8U) /* Return the header */ do + { + png_uint_32 b; + unsigned int shift; + + if (chunkpos < 4U) + b = chunklen - 12U; + + else + b = chunktype; + + shift = 3U & chunkpos; + ++chunkpos; + + if (shift < 3U) + b >>= 8U*(3U-shift); + + *pb++ = 0xffU & b; + } + while (--st > 0 && chunkpos < 8); + + else /* Return chunk bytes, including the CRC */ + { + png_size_t avail = st; + + if (avail > chunklen - chunkpos) + avail = (png_size_t)/*SAFE*/(chunklen - chunkpos); + + store_read_imp(ps, pb, avail); + pb += avail; + st -= avail; + chunkpos += (png_uint_32)/*SAFE*/avail; + + /* Check for end of chunk and end-of-file; don't try to read a new + * chunk header at this point unless instructed to do so by 'min'. + */ + if (chunkpos >= chunklen && max-st >= min && + store_read_buffer_avail(ps) == 0) + break; + } + } /* !IDAT */ + } + while (st > 0); + + ps->chunklen = chunklen; + ps->chunktype = chunktype; + ps->chunkpos = chunkpos; + + return st; /* space left */ +} + +static void PNGCBAPI +store_read(png_structp ppIn, png_bytep pb, png_size_t st) +{ + png_const_structp pp = ppIn; + 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_chunk(ps, pb, st, st); +} + +static void +store_progressive_read(png_store *ps, png_structp pp, png_infop pi) +{ + if (ps->pread != pp || ps->current == NULL || ps->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. + */ + while (store_read_buffer_avail(ps) > 0) + { + static png_uint_32 noise = 2; + png_size_t cb; + png_byte buffer[512]; + + /* Generate 15 more bits of stuff: */ + noise = (noise << 9) | ((noise ^ (noise >> (9-5))) & 0x1ff); + cb = noise & 0x1ff; + cb -= store_read_chunk(ps, buffer, cb, 1); + png_process_data(pp, pi, buffer, cb); + } +} +#endif /* PNG_READ_SUPPORTED */ + +/* 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; +} + +#ifdef PNG_READ_SUPPORTED +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); + return NULL; + } + + /* The result may be null if there is no palette. */ + *npalette = ps->current->npalette; + return ps->current->palette; +} +#endif /* PNG_READ_SUPPORTED */ + +/***************************** MEMORY MANAGEMENT*** ***************************/ +#ifdef PNG_USER_MEM_SUPPORTED +/* 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_const_structp pp, 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_const_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, (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 PNGCBAPI +store_malloc(png_structp ppIn, png_alloc_size_t cb) +{ + png_const_structp pp = ppIn; + 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 PNGCBAPI +store_free(png_structp ppIn, png_voidp memory) +{ + png_const_structp pp = ppIn; + 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); +} +#endif /* PNG_USER_MEM_SUPPORTED */ + +/* 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. + */ +# ifdef PNG_USER_MEM_SUPPORTED + store_pool_delete(ps, &ps->write_memory_pool); +# endif + + 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, const char *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, also if user + * memory is not supported we can't do it anyway. + */ +# ifdef PNG_USER_MEM_SUPPORTED + if (!ps->speed) + ps->pwrite = png_create_write_struct_2(PNG_LIBPNG_VER_STRING, + ps, store_error, store_warning, &ps->write_memory_pool, + store_malloc, store_free); + + else +# endif + ps->pwrite = png_create_write_struct(PNG_LIBPNG_VER_STRING, + ps, store_error, store_warning); + + png_set_write_fn(ps->pwrite, ps, store_write, store_flush); + +# ifdef PNG_SET_OPTION_SUPPORTED + { + int opt; + for (opt=0; opt<ps->noptions; ++opt) + if (png_set_option(ps->pwrite, ps->options[opt].option, + ps->options[opt].setting) == PNG_OPTION_INVALID) + png_error(ps->pwrite, "png option invalid"); + } +# endif + + 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). + * This routine exists even when there is no read support to make the code + * tidier (avoid a mass of ifdefs) and so easier to maintain. + */ +static void +store_read_reset(png_store *ps) +{ +# ifdef PNG_READ_SUPPORTED + 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; + } +# endif + +# ifdef PNG_USER_MEM_SUPPORTED + /* Always do this to be safe. */ + store_pool_delete(ps, &ps->read_memory_pool); +# endif + + ps->current = NULL; + ps->next = NULL; + ps->readpos = 0; + ps->validated = 0; + + ps->chunkpos = 8; + ps->chunktype = 0; + ps->chunklen = 16; + ps->IDAT_size = 0; +} + +#ifdef PNG_READ_SUPPORTED +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; + ps->IDAT_size = pf->IDAT_size; + ps->IDAT_bits = pf->IDAT_bits; /* just a cache */ + ps->IDAT_len = 0; + ps->IDAT_pos = 0; + ps->IDAT_crc = 0UL; + 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, + 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. + */ +# ifdef PNG_USER_MEM_SUPPORTED + if (!ps->speed) + ps->pread = png_create_read_struct_2(PNG_LIBPNG_VER_STRING, ps, + store_error, store_warning, &ps->read_memory_pool, store_malloc, + store_free); + + else +# endif + ps->pread = png_create_read_struct(PNG_LIBPNG_VER_STRING, ps, store_error, + store_warning); + + 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; + } + +# ifdef PNG_SET_OPTION_SUPPORTED + { + int opt; + for (opt=0; opt<ps->noptions; ++opt) + if (png_set_option(ps->pread, ps->options[opt].option, + ps->options[opt].setting) == PNG_OPTION_INVALID) + png_error(ps->pread, "png option invalid"); + } +# endif + + store_read_set(ps, id); + + if (ppi != NULL) + *ppi = ps->piread = png_create_info_struct(ps->pread); + + return ps->pread; +} +#endif /* PNG_READ_SUPPORTED */ + +/* 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; + +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; + +#ifdef PNG_READ_SUPPORTED +#if defined PNG_READ_TRANSFORMS_SUPPORTED && defined PNG_READ_cHRM_SUPPORTED +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); +} + +static CIE_color +white_point(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; +} +#endif /* READ_TRANSFORMS && READ_cHRM */ + +#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED +static void +normalize_color_encoding(color_encoding *encoding) +{ + 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; + } +} +#endif + +#ifdef PNG_READ_TRANSFORMS_SUPPORTED +static size_t +safecat_color_encoding(char *buffer, size_t bufsize, size_t pos, + 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; +} +#endif /* READ_TRANSFORMS */ +#endif /* PNG_READ_SUPPORTED */ + +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 */ + const color_encoding *encodings; + unsigned int nencodings; + 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 (pre-1.7 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 maxcalcG; /* 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. + * + * NOTE: this is not checked in release builds. + */ + 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 combination of transforms, */ + unsigned int test_transform :1; + unsigned int test_tRNS :1; /* Includes tRNS images */ + + /* When to use the use_input_precision option, this controls the gamma + * validation code checks. If set any value that is within the transformed + * range input-.5 to input+.5 will be accepted, otherwise the value must be + * within the normal limits. It should not be necessary to set this; the + * result should always be exact within the permitted error limits. + */ + 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 the sample + * depth is 8 bits. + */ + 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; + + /* Whether or not to run the low-bit-depth grayscale tests. This fails on + * gamma images in some cases because of gross inaccuracies in the grayscale + * gamma handling for low bit depth. + */ + unsigned int test_lbg :1; + unsigned int test_lbg_gamma_threshold :1; + unsigned int test_lbg_gamma_transform :1; + unsigned int test_lbg_gamma_sbit :1; + unsigned int test_lbg_gamma_composition :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->maxcalcG = 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; +# ifdef PNG_WRITE_tRNS_SUPPORTED + pm->test_tRNS = 1; +# else + pm->test_tRNS = 0; +# endif + pm->use_input_precision = 0; + pm->use_input_precision_sbit = 0; + pm->use_input_precision_16to8 = 0; + pm->calculations_use_input_precision = 0; + pm->assume_16_bit_calculations = 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_lbg = 1; + pm->test_lbg_gamma_threshold = 1; + pm->test_lbg_gamma_transform = 1; + pm->test_lbg_gamma_sbit = 1; + pm->test_lbg_gamma_composition = 1; + 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 + +/* This controls use of checks that explicitly know how libpng digitizes the + * samples in calculations; setting this circumvents simple error limit checking + * in the rgb_to_gray check, replacing it with an exact copy of the libpng 1.5 + * algorithm. + */ +#define DIGITIZE PNG_LIBPNG_VER < 10700 + +/* If pm->calculations_use_input_precision is set then operations will happen + * with the precision of the input, not the precision of the output depth. + * + * 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. + */ +#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED +#if DIGITIZE +static double digitize(double value, int 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. + */ + const unsigned int digitization_factor = (1U << depth) -1; + + /* 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; +} +#endif +#endif /* RGB_TO_GRAY */ + +#ifdef PNG_READ_GAMMA_SUPPORTED +static double abserr(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 || + (pm->calculations_use_input_precision ? in_depth : out_depth) == 16) + return pm->maxabs16; + else + return pm->maxabs8; +} + +static double calcerr(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->calculations_use_input_precision ? in_depth : out_depth) == 16) + return pm->maxcalc16; + else if (pm->assume_16_bit_calculations) + return pm->maxcalcG; + else + return pm->maxcalc8; +} + +static double pcerr(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 || + (pm->calculations_use_input_precision ? in_depth : out_depth) == 16) + 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(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 ((pm->calculations_use_input_precision ? in_depth : out_depth) == 16) + 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(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 ((pm->calculations_use_input_precision ? in_depth : out_depth) == 16) + { + 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(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; +} +#endif /* PNG_READ_GAMMA_SUPPORTED */ + +/* 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); +} + +#ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED +static void +modifier_current_encoding(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; +} +#endif + +#ifdef PNG_READ_TRANSFORMS_SUPPORTED +static size_t +safecat_current_encoding(char *buffer, size_t bufsize, size_t pos, + 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; +} +#endif + +/* 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(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(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(const png_modifier *pm) +{ + return pm->current_gamma != 0; +} + +/* 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_chunk(&pm->this, pm->buffer, 8, 8); /* 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_chunk(&pm->this, pm->buffer, 13+12, 13+12); /* 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_chunk(&pm->this, pb, cb, 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_chunk(&pm->this, pm->buffer, 8, 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) + { + png_size_t s = len+12-pm->buffer_count; + store_read_chunk(&pm->this, pm->buffer+pm->buffer_count, s, s); + 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 PNGCBAPI +modifier_read(png_structp ppIn, png_bytep pb, png_size_t st) +{ + png_const_structp pp = ppIn; + 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, + 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; + 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, + 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; +} + +#ifdef PNG_READ_GAMMA_SUPPORTED +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_GAMMA_SUPPORTED */ +#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. + * + * Because the PNG filter code is typically the largest CPU consumer within + * libpng itself there is a tendency to attempt to optimize it. This results in + * special case code which needs to be validated. To cause this to happen the + * 'size' images are made to use each possible filter, in so far as this is + * possible for smaller images. + * + * 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] = (png_byte)((i&1) ? 255U : 0U); + values[i][2] = (png_byte)((i&2) ? 255U : 0U); + values[i][3] = (png_byte)((i&4) ? 255U : 0U); + } + + /* 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. + */ +/* TODO: the png_structp here can probably be 'const' in the future */ +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; + +#ifdef PNG_WRITE_tRNS_SUPPORTED + if (j > 0) + png_set_tRNS(pp, pi, tRNS, j, 0/*color*/); +#endif + } +} + +#ifdef PNG_WRITE_tRNS_SUPPORTED +static void +set_random_tRNS(png_structp pp, png_infop pi, const png_byte colour_type, + const int bit_depth) +{ + /* To make this useful the tRNS color needs to match at least one pixel. + * Random values are fine for gray, including the 16-bit case where we know + * that the test image contains all the gray values. For RGB we need more + * method as only 65536 different RGB values are generated. + */ + png_color_16 tRNS; + const png_uint_16 mask = (png_uint_16)((1U << bit_depth)-1); + + R8(tRNS); /* makes unset fields random */ + + if (colour_type & 2/*RGB*/) + { + if (bit_depth == 8) + { + tRNS.red = random_u16(); + tRNS.green = random_u16(); + tRNS.blue = tRNS.red ^ tRNS.green; + tRNS.red &= mask; + tRNS.green &= mask; + tRNS.blue &= mask; + } + + else /* bit_depth == 16 */ + { + tRNS.red = random_u16(); + tRNS.green = (png_uint_16)(tRNS.red * 257); + tRNS.blue = (png_uint_16)(tRNS.green * 17); + } + } + + else + { + tRNS.gray = random_u16(); + tRNS.gray &= mask; + } + + png_set_tRNS(pp, pi, NULL, 0, &tRNS); +} +#endif + +/* 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_const_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_const_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_const_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_const_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 */ + } +} + +#ifdef PNG_READ_SUPPORTED +/* The following can only be defined here, now we have the definitions + * of the transform image sizes. + */ +static png_uint_32 +standard_width(png_const_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_const_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_const_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; +} +#endif /* PNG_READ_SUPPORTED */ + +static void +transform_row(png_const_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] = (png_byte)(v & 0xff), v += 17, ++i; + return; + + case 2: + while (i<128/4) buffer[i] = (png_byte)(v & 0xff), v += 33, ++i; + return; + + case 4: + while (i<128/2) buffer[i] = (png_byte)(v & 0xff), v += 65, ++i; + return; + + case 8: + /* 256 bytes total, 128 bytes in each row set as follows: */ + while (i<128) buffer[i] = (png_byte)(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] = (png_byte)((v>>8) & 0xff); + buffer[2*i+1] = (png_byte)(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] = (png_byte)((v >> 8) & 0xff); + buffer[3*i+1] = (png_byte)(v & 0xff); + buffer[3*i+2] = (png_byte)(((v >> 8) ^ v) & 0xff); + ++v; + ++i; + } + + return; + + case 32: + /* 65535 pixels, r, g, b, a; just replicate */ + while (i<128) + { + buffer[4*i+0] = (png_byte)((v >> 8) & 0xff); + buffer[4*i+1] = (png_byte)(v & 0xff); + buffer[4*i+2] = (png_byte)((v >> 8) & 0xff); + buffer[4*i+3] = (png_byte)(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] = (png_byte)((t >> 8) & 0xff); + buffer[6*i+1] = (png_byte)(t & 0xff); + t *= 257; + buffer[6*i+2] = (png_byte)((t >> 8) & 0xff); + buffer[6*i+3] = (png_byte)(t & 0xff); + t *= 17; + buffer[6*i+4] = (png_byte)((t >> 8) & 0xff); + buffer[6*i+5] = (png_byte)(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] = (png_byte)((t >> 8) & 0xff); + buffer[8*i+1] = (png_byte)(t & 0xff); + buffer[8*i+4] = (png_byte)((t >> 8) & 0xff); + buffer[8*i+5] = (png_byte)(t & 0xff); + t *= 257; + buffer[8*i+2] = (png_byte)((t >> 8) & 0xff); + buffer[8*i+3] = (png_byte)(t & 0xff); + buffer[8*i+6] = (png_byte)((t >> 8) & 0xff); + buffer[8*i+7] = (png_byte)(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))) + +/* This is just a helper for compiling on minimal systems with no write + * interlacing support. If there is no write interlacing we can't generate test + * cases with interlace: + */ +#ifdef PNG_WRITE_INTERLACING_SUPPORTED +# define INTERLACE_LAST PNG_INTERLACE_LAST +# define check_interlace_type(type) ((void)(type)) +# define set_write_interlace_handling(pp,type) png_set_interlace_handling(pp) +# define do_own_interlace 0 +#elif PNG_LIBPNG_VER < 10700 +# define set_write_interlace_handling(pp,type) (1) +static void +check_interlace_type(int const interlace_type) +{ + /* Prior to 1.7.0 libpng does not support the write of an interlaced image + * unless PNG_WRITE_INTERLACING_SUPPORTED, even with do_interlace so the + * code here does the pixel interlace itself, so: + */ + if (interlace_type != PNG_INTERLACE_NONE) + { + /* This is an internal error - --interlace tests should be skipped, not + * attempted. + */ + fprintf(stderr, "pngvalid: no interlace support\n"); + exit(99); + } +} +# define INTERLACE_LAST (PNG_INTERLACE_NONE+1) +# define do_own_interlace 0 +#else /* libpng 1.7+ */ +# define set_write_interlace_handling(pp,type)\ + npasses_from_interlace_type(pp,type) +# define check_interlace_type(type) ((void)(type)) +# define INTERLACE_LAST PNG_INTERLACE_LAST +# define do_own_interlace 1 +#endif /* WRITE_INTERLACING tests */ + +#if PNG_LIBPNG_VER >= 10700 || defined PNG_WRITE_INTERLACING_SUPPORTED +# define CAN_WRITE_INTERLACE 1 +#else +# define CAN_WRITE_INTERLACE 0 +#endif + +/* Do the same thing for read interlacing; this controls whether read tests do + * their own de-interlace or use libpng. + */ +#ifdef PNG_READ_INTERLACING_SUPPORTED +# define do_read_interlace 0 +#else /* no libpng read interlace support */ +# define do_read_interlace 1 +#endif +/* 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, int littleendian) +{ + 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. + * + * It is OK for buffer and imageRow to be identical, because 'xin' moves + * faster than 'xout' and we copy up. + */ + 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, littleendian); + ++xout; + } +} + +#ifdef PNG_READ_SUPPORTED +static void +deinterlace_row(png_bytep buffer, png_const_bytep row, + unsigned int pixel_size, png_uint_32 w, int pass, int littleendian) +{ + /* 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, littleendian); + ++xin; + } +} +#endif /* PNG_READ_SUPPORTED */ + +/* Make a standardized image given 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. + */ +#ifdef PNG_WRITE_FILTER_SUPPORTED +static void +choose_random_filter(png_structp pp, int start) +{ + /* Choose filters randomly except that on the very first row ensure that + * there is at least one previous row filter. + */ + int filters = PNG_ALL_FILTERS & random_mod(256U); + + /* There may be no filters; skip the setting. */ + if (filters != 0) + { + if (start && filters < PNG_FILTER_UP) + filters |= PNG_FILTER_UP; + + png_set_filter(pp, 0/*method*/, filters); + } +} +#else /* !WRITE_FILTER */ +# define choose_random_filter(pp, start) ((void)0) +#endif /* !WRITE_FILTER */ + +static void +make_transform_image(png_store* const ps, png_byte const colour_type, + png_byte const bit_depth, unsigned int palette_number, + int interlace_type, png_const_charp name) +{ + context(ps, fault); + + check_interlace_type(interlace_type); + + Try + { + png_infop pi; + png_structp pp = set_store_for_write(ps, &pi, name); + png_uint_32 h, w; + + /* 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; + + w = transform_width(pp, colour_type, bit_depth); + h = transform_height(pp, colour_type, bit_depth); + + png_set_IHDR(pp, pi, w, h, bit_depth, colour_type, interlace_type, + PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE); + +#ifdef PNG_TEXT_SUPPORTED +# if defined(PNG_READ_zTXt_SUPPORTED) && defined(PNG_WRITE_zTXt_SUPPORTED) +# define TEXT_COMPRESSION PNG_TEXT_COMPRESSION_zTXt +# else +# define TEXT_COMPRESSION PNG_TEXT_COMPRESSION_NONE +# endif + { + 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 = TEXT_COMPRESSION; + 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*/); + +# ifdef PNG_WRITE_tRNS_SUPPORTED + else if (palette_number) + set_random_tRNS(pp, pi, colour_type, bit_depth); +# endif + + png_write_info(pp, pi); + + if (png_get_rowbytes(pp, pi) != + transform_rowsize(pp, colour_type, bit_depth)) + png_error(pp, "transform 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 = set_write_interlace_handling(pp, interlace_type); + 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; + + /* do_own_interlace is a pre-defined boolean (a #define) which is + * set if we have to work out the interlaced rows here. + */ + for (y=0; y<h; ++y) + { + png_byte buffer[TRANSFORM_ROWMAX]; + + transform_row(pp, buffer, colour_type, bit_depth, y); + +# if do_own_interlace + /* If do_own_interlace *and* the image is interlaced we need a + * reduced interlace row; this may be reduced to empty. + */ + if (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) && + PNG_PASS_COLS(w, pass) > 0) + interlace_row(buffer, buffer, + bit_size(pp, colour_type, bit_depth), w, pass, + 0/*data always bigendian*/); + else + continue; + } +# endif /* do_own_interlace */ + + choose_random_filter(pp, pass == 0 && y == 0); + 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 = TEXT_COMPRESSION; + 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_modifier *pm) +{ + png_byte colour_type = 0; + png_byte bit_depth = 0; + unsigned int palette_number = 0; + + /* This is in case of errors. */ + safecat(pm->this.test, sizeof pm->this.test, 0, "make standard images"); + + /* Use next_format to enumerate all the combinations we test, including + * generating multiple low bit depth palette images. Non-A images (palette + * and direct) are created with and without tRNS chunks. + */ + while (next_format(&colour_type, &bit_depth, &palette_number, 1, 1)) + { + int interlace_type; + + for (interlace_type = PNG_INTERLACE_NONE; + interlace_type < 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, do_own_interlace); + make_transform_image(&pm->this, colour_type, bit_depth, palette_number, + interlace_type, name); + } + } +} + +/* 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* const ps, png_byte const colour_type, + png_byte const bit_depth, int const interlace_type, + png_uint_32 const w, png_uint_32 const h, + int const do_interlace) +{ + context(ps, fault); + + check_interlace_type(interlace_type); + + 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]; + 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); + +#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 = TEXT_COMPRESSION; + 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, 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, "size 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 != set_write_interlace_handling(pp, interlace_type)) + 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: */ + 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, + 0/*data always bigendian*/); + row = tempRow; + } + else + continue; + } + +# ifdef PNG_WRITE_FILTER_SUPPORTED + /* Only get to here if the row has some pixels in it, set the + * filters to 'all' for the very first row and thereafter to a + * single filter. It isn't well documented, but png_set_filter + * does accept a filter number (per the spec) as well as a bit + * mask. + * + * The code now uses filters at random, except that on the first + * row of an image it ensures that a previous row filter is in + * the set so that libpng allocates the row buffer. + */ + { + int filters = 8 << random_mod(PNG_FILTER_VALUE_LAST); + + if (pass == 0 && y == 0 && + (filters < PNG_FILTER_UP || w == 1U)) + filters |= PNG_FILTER_UP; + + png_set_filter(pp, 0/*method*/, filters); + } +# endif + + png_write_row(pp, row); + } + } + } + +#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 = TEXT_COMPRESSION; + 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, 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* const ps, png_byte const colour_type, int bdlo, + int 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); +# ifdef PNG_WRITE_INTERLACING_SUPPORTED + make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_ADAM7, + width, height, 0); +# endif +# if CAN_WRITE_INTERLACE + /* 1.7.0 removes the hack that prevented app write of an interlaced + * image if WRITE_INTERLACE was not supported + */ + make_size_image(ps, colour_type, DEPTH(bdlo), PNG_INTERLACE_ADAM7, + width, height, 1); +# endif + } + } + } +} + +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); +} + +#ifdef PNG_READ_SUPPORTED +/* Return a row based on image id and 'y' for checking: */ +static void +standard_row(png_const_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); +} +#endif /* PNG_READ_SUPPORTED */ + +/* 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! + */ +/* TODO: the 'set' functions can probably all be made to take a + * png_const_structp rather than a modifiable one. + */ +#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 const struct +{ + void (*fn)(png_structp, png_infop); + const char *msg; + unsigned int warning :1; /* the error is a warning... */ +} error_test[] = + { + /* no warnings makes these errors undetectable prior to 1.7.0 */ + { sBIT0_error_fn, "sBIT(0): failed to detect error", + PNG_LIBPNG_VER < 10700 }, + + { sBIT_error_fn, "sBIT(too big): failed to detect error", + PNG_LIBPNG_VER < 10700 }, + }; + +static void +make_error(png_store* const ps, png_byte const colour_type, + png_byte bit_depth, int interlace_type, int test, png_const_charp name) +{ + context(ps, fault); + + check_interlace_type(interlace_type); + + Try + { + png_infop pi; + const png_structp pp = set_store_for_write(ps, &pi, name); + png_uint_32 w, h; + gnu_volatile(pp) + + if (pp == NULL) + Throw ps; + + w = transform_width(pp, colour_type, bit_depth); + gnu_volatile(w) + h = transform_height(pp, colour_type, bit_depth); + gnu_volatile(h) + 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*/); + + /* 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 + { + gnu_volatile(exception__prev) + + /* 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) + { /* expected exit */ + } +#undef exception__prev +#undef exception__env + + /* And clear these flags */ + ps->expect_warning = 0; + + if (ps->expect_error) + ps->expect_error = 0; + + else + { + /* Now write the whole image, just to make sure that the detected, or + * undetected, errro has not created problems inside libpng. This + * doesn't work if there was a png_error in png_write_info because that + * can abort before PLTE was written. + */ + if (png_get_rowbytes(pp, pi) != + transform_rowsize(pp, colour_type, bit_depth)) + png_error(pp, "row size incorrect"); + + else + { + int npasses = set_write_interlace_handling(pp, interlace_type); + 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); + +# if do_own_interlace + /* If do_own_interlace *and* the image is interlaced we + * need a reduced interlace row; this may be reduced to + * empty. + */ + if (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) && + PNG_PASS_COLS(w, pass) > 0) + interlace_row(buffer, buffer, + bit_size(pp, colour_type, bit_depth), w, pass, + 0/*data always bigendian*/); + else + continue; + } +# endif /* do_own_interlace */ + + png_write_row(pp, buffer); + } + } + } /* image writing */ + + 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* const pm, png_byte const colour_type, + int bdlo, int const bdhi) +{ + for (; bdlo <= bdhi; ++bdlo) + { + int interlace_type; + + for (interlace_type = PNG_INTERLACE_NONE; + interlace_type < 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, do_own_interlace); + + for (test=0; test<ARRAY_SIZE(error_test); ++test) + { + make_error(&pm->this, colour_type, DEPTH(bdlo), interlace_type, + test, name); + + if (fail(pm)) + return 0; + } + } + } + + return 1; /* keep going */ +} +#endif /* PNG_WARNINGS_SUPPORTED */ + +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 *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; +# if PNG_LIBPNG_VER >= 10600 + char timestring[29]; +# endif + 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 */ + +# if PNG_LIBPNG_VER < 10600 + result = png_convert_to_rfc1123(pp, &pt); +# else + if (png_convert_to_rfc1123_buffer(timestring, &pt)) + result = timestring; + + else + result = NULL; +# endif + + 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 +} + +#ifdef PNG_READ_SUPPORTED +/* 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; + png_byte interlace_type; + png_byte filler; /* Output has a filler */ + 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 littleendian; /* App (row) data is little endian */ + int is_transparent; /* Transparency information was present. */ + int has_tRNS; /* color type GRAY or RGB with a tRNS chunk. */ + 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); + check_interlace_type(dp->interlace_type); + 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->littleendian = 0; + 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_const_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_const_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->has_tRNS = 1; + break; + + case 2: + dp->transparent.red = trans_color->red; + dp->transparent.green = trans_color->green; + dp->transparent.blue = trans_color->blue; + dp->has_tRNS = 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) + { +# ifdef PNG_READ_INTERLACING_SUPPORTED + if (dp->npasses != png_set_interlace_handling(pp)) + png_error(pp, "validate: file changed interlace type"); +# else /* !READ_INTERLACING */ + /* This should never happen: the relevant tests (!do_interlace) should + * not be run. + */ + if (dp->npasses > 1) + png_error(pp, "validate: no libpng interlace support"); +# endif /* !READ_INTERLACING */ + } + + /* 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_const_structp pp, + png_const_infop pi, int nImages) +{ + /* Record cbRow now that it can be found. */ + { + png_byte ct = png_get_color_type(pp, pi); + png_byte bd = png_get_bit_depth(pp, pi); + + if (bd >= 8 && (ct == PNG_COLOR_TYPE_RGB || ct == PNG_COLOR_TYPE_GRAY) && + dp->filler) + ct |= 4; /* handle filler as faked alpha channel */ + + dp->pixel_size = bit_size(pp, ct, bd); + } + 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 PNGCBAPI +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 PNGCBAPI +progressive_row(png_structp ppIn, png_bytep new_row, png_uint_32 y, int pass) +{ + png_const_structp pp = ppIn; + 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 /* USER_TRANSFORM_INFO */ + + 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); + + /* Combine the new row into the old: */ +#ifdef PNG_READ_INTERLACING_SUPPORTED + if (dp->do_interlace) +#endif /* READ_INTERLACING */ + { + if (dp->interlace_type == PNG_INTERLACE_ADAM7) + deinterlace_row(row, new_row, dp->pixel_size, dp->w, pass, + dp->littleendian); + else + row_copy(row, new_row, dp->pixel_size * dp->w, dp->littleendian); + } +#ifdef PNG_READ_INTERLACING_SUPPORTED + else + png_progressive_combine_row(pp, row, new_row); +#endif /* PNG_READ_INTERLACING_SUPPORTED */ + } + + 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"); +} + +static void +sequential_row(standard_display *dp, png_structp pp, png_infop pi, + const int iImage, const int iDisplay) +{ + const int npasses = dp->npasses; + const int do_interlace = dp->do_interlace && + dp->interlace_type == PNG_INTERLACE_ADAM7; + const png_uint_32 height = standard_height(pp, dp->id); + const png_uint_32 width = standard_width(pp, dp->id); + 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, dp->littleendian); + + if (iDisplay >= 0) + deinterlace_row(store_image_row(ps, pp, iDisplay, y), display, + dp->pixel_size, dp->w, pass, dp->littleendian); + } + } + 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); +} + +#ifdef PNG_TEXT_SUPPORTED +static void +standard_check_text(png_const_structp pp, png_const_textp tp, + png_const_charp keyword, png_const_charp text) +{ + char msg[1024]; + size_t pos = safecat(msg, sizeof msg, 0, "text: "); + size_t ok; + + pos = safecat(msg, sizeof msg, pos, keyword); + pos = safecat(msg, sizeof msg, pos, ": "); + ok = pos; + + if (tp->compression != TEXT_COMPRESSION) + { + char buf[64]; + + sprintf(buf, "compression [%d->%d], ", TEXT_COMPRESSION, + tp->compression); + pos = safecat(msg, sizeof msg, pos, buf); + } + + if (tp->key == NULL || strcmp(tp->key, keyword) != 0) + { + pos = safecat(msg, sizeof msg, pos, "keyword \""); + if (tp->key != NULL) + { + pos = safecat(msg, sizeof msg, pos, tp->key); + pos = safecat(msg, sizeof msg, pos, "\", "); + } + + else + pos = safecat(msg, sizeof msg, pos, "null, "); + } + + if (tp->text == NULL) + pos = safecat(msg, sizeof msg, pos, "text lost, "); + + else + { + if (tp->text_length != strlen(text)) + { + char buf[64]; + sprintf(buf, "text length changed[%lu->%lu], ", + (unsigned long)strlen(text), (unsigned long)tp->text_length); + pos = safecat(msg, sizeof msg, pos, buf); + } + + if (strcmp(tp->text, text) != 0) + { + pos = safecat(msg, sizeof msg, pos, "text becomes \""); + pos = safecat(msg, sizeof msg, pos, tp->text); + pos = safecat(msg, sizeof msg, pos, "\" (was \""); + pos = safecat(msg, sizeof msg, pos, text); + pos = safecat(msg, sizeof msg, pos, "\"), "); + } + } + + if (tp->itxt_length != 0) + pos = safecat(msg, sizeof msg, pos, "iTXt length set, "); + + if (tp->lang != NULL) + { + pos = safecat(msg, sizeof msg, pos, "iTXt language \""); + pos = safecat(msg, sizeof msg, pos, tp->lang); + pos = safecat(msg, sizeof msg, pos, "\", "); + } + + if (tp->lang_key != NULL) + { + pos = safecat(msg, sizeof msg, pos, "iTXt keyword \""); + pos = safecat(msg, sizeof msg, pos, tp->lang_key); + pos = safecat(msg, sizeof msg, pos, "\", "); + } + + if (pos > ok) + { + msg[pos-2] = '\0'; /* Remove the ", " at the end */ + png_error(pp, msg); + } +} + +static void +standard_text_validate(standard_display *dp, png_const_structp pp, + png_infop pi, int check_end) +{ + png_textp tp = NULL; + png_uint_32 num_text = png_get_text(pp, pi, &tp, NULL); + + if (num_text == 2 && tp != NULL) + { + standard_check_text(pp, tp, "image name", dp->ps->current->name); + + /* This exists because prior to 1.5.18 the progressive reader left the + * png_struct z_stream unreset at the end of the image, so subsequent + * attempts to use it simply returns Z_STREAM_END. + */ + if (check_end) + standard_check_text(pp, tp+1, "end marker", "end"); + } + + else + { + char msg[64]; + + sprintf(msg, "expected two text items, got %lu", + (unsigned long)num_text); + png_error(pp, msg); + } +} +#else +# define standard_text_validate(dp,pp,pi,check_end) ((void)0) +#endif + +static void +standard_row_validate(standard_display *dp, png_const_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 (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[%lu][%d] changed from %.2x to %.2x", + (unsigned long)y, where-1, std[where-1], + store_image_row(dp->ps, pp, iImage, y)[where-1]); + png_error(pp, msg); + } + + 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[%lu][%d] changed from %.2x to %.2x", + (unsigned long)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_const_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 PNGCBAPI +standard_end(png_structp ppIn, png_infop pi) +{ + png_const_structp pp = ppIn; + 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_text_validate(dp, pp, pi, + PNG_LIBPNG_VER >= 10518/*check_end: see comments above*/); + 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* const psIn, png_uint_32 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_text_validate(&d, pp, pi, 1/*check_end*/); + 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* const pm, png_byte const colour_type, + int bdlo, int const bdhi) +{ + for (; bdlo <= bdhi; ++bdlo) + { + int interlace_type; + + for (interlace_type = PNG_INTERLACE_NONE; + interlace_type < INTERLACE_LAST; ++interlace_type) + { + standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/, + interlace_type, 0, 0, 0), do_read_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* const pm, png_byte const colour_type, + int bdlo, int 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 const png_byte hinc[] = {1, 3, 11, 1, 5}; + static const png_byte winc[] = {1, 9, 5, 7, 1}; + const int save_bdlo = bdlo; + + 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; + + /* 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; + +# if CAN_WRITE_INTERLACE + /* Validate the pngvalid code itself: */ + standard_test(&pm->this, FILEID(colour_type, DEPTH(bdlo), 0/*palette*/, + PNG_INTERLACE_ADAM7, w, h, 1), 1/*do_interlace*/, + pm->use_update_info); + + if (fail(pm)) + return 0; +# endif + } + } + + /* Now do the tests of libpng interlace handling, after we have made sure + * that the pngvalid version works: + */ + for (bdlo = save_bdlo; bdlo <= bdhi; ++bdlo) + { + png_uint_32 h, w; + + for (h=1; h<=16; h+=hinc[bdlo]) for (w=1; w<=16; w+=winc[bdlo]) + { +# ifdef PNG_READ_INTERLACING_SUPPORTED + /* Test with pngvalid generated interlaced images first; we have + * already verify these are ok (unless pngvalid has self-consistent + * read/write errors, which is unlikely), so this detects errors in the + * read side first: + */ +# if CAN_WRITE_INTERLACE + 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; +# endif +# endif /* READ_INTERLACING */ + +# ifdef PNG_WRITE_INTERLACING_SUPPORTED + /* Test the libpng write side against the pngvalid read side: */ + 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; +# endif + +# ifdef PNG_READ_INTERLACING_SUPPORTED +# ifdef PNG_WRITE_INTERLACING_SUPPORTED + /* Test both together: */ + 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; +# endif +# endif /* READ_INTERLACING */ + } + } + + 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 */ + unsigned int have_tRNS :1; /* tRNS chunk may need processing */ + unsigned int swap_rgb :1; /* RGB swapped to BGR */ + unsigned int alpha_first :1; /* Alpha at start, not end */ + unsigned int alpha_inverted :1; /* Alpha channel inverted */ + unsigned int mono_inverted :1; /* Gray channel inverted */ + unsigned int swap16 :1; /* Byte swap 16-bit components */ + unsigned int littleendian :1; /* High bits on right */ + unsigned int sig_bits :1; /* Pixel shifted (sig bits only) */ + + /* 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. + * + * If sig_bits is set above the red, green, blue and alpha values have been + * scaled so they only contain the significant bits of the component values. + */ + 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 rMax, unsigned int gMax, + unsigned int bMax, unsigned int aMax) +{ + this->redf = this->red / (double)rMax; + this->greenf = this->green / (double)gMax; + this->bluef = this->blue / (double)bMax; + this->alphaf = this->alpha / (double)aMax; + + if (this->red < rMax) + this->rede = this->redf * DBL_EPSILON; + else + this->rede = 0; + if (this->green < gMax) + this->greene = this->greenf * DBL_EPSILON; + else + this->greene = 0; + if (this->blue < bMax) + this->bluee = this->bluef * DBL_EPSILON; + else + this->bluee = 0; + if (this->alpha < aMax) + 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, + const image_pixel *format /*from pngvalid transform of input*/) +{ + const png_byte sample_depth = (png_byte)(colour_type == + PNG_COLOR_TYPE_PALETTE ? 8 : bit_depth); + const unsigned int max = (1U<<sample_depth)-1; + const int swap16 = (format != 0 && format->swap16); + const int littleendian = (format != 0 && format->littleendian); + const int sig_bits = (format != 0 && format->sig_bits); + + /* 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, swap16, littleendian); + 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) + { + 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 & 4) != 0 && format != 0 && format->alpha_first) + { + this->alpha = this->red; + /* This handles the gray case for 'AG' pixels */ + this->palette_index = this->red = this->green = this->blue = + sample(row, colour_type, bit_depth, x, 1, swap16, littleendian); + i = 1; + } + + if (colour_type & 2) + { + /* Green is second for both BGR and RGB: */ + this->green = sample(row, colour_type, bit_depth, x, ++i, swap16, + littleendian); + + if (format != 0 && format->swap_rgb) /* BGR */ + this->red = sample(row, colour_type, bit_depth, x, ++i, swap16, + littleendian); + else + this->blue = sample(row, colour_type, bit_depth, x, ++i, swap16, + littleendian); + } + + else /* grayscale */ if (format != 0 && format->mono_inverted) + this->red = this->green = this->blue = this->red ^ max; + + if ((colour_type & 4) != 0) /* alpha */ + { + if (format == 0 || !format->alpha_first) + this->alpha = sample(row, colour_type, bit_depth, x, ++i, swap16, + littleendian); + + if (format != 0 && format->alpha_inverted) + this->alpha ^= max; + } + } + + /* 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, + sig_bits ? (1U << format->red_sBIT)-1 : max, + sig_bits ? (1U << format->green_sBIT)-1 : max, + sig_bits ? (1U << format->blue_sBIT)-1 : max, + sig_bits ? (1U << format->alpha_sBIT)-1 : 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; + this->swap_rgb = 0; + this->alpha_first = 0; + this->alpha_inverted = 0; + this->mono_inverted = 0; + this->swap16 = 0; + this->littleendian = 0; + this->sig_bits = 0; +} + +#if defined PNG_READ_EXPAND_SUPPORTED || defined PNG_READ_GRAY_TO_RGB_SUPPORTED\ + || defined PNG_READ_EXPAND_SUPPORTED || defined PNG_READ_EXPAND_16_SUPPORTED\ + || defined PNG_READ_BACKGROUND_SUPPORTED +/* 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 prior to 1.7.0. Palette images will be converted to alpha (using + * the above API). With png_set_background the alpha channel is never expanded + * but this routine is used by pngvalid to simplify code; 'for_background' + * records this. + */ +static void +image_pixel_add_alpha(image_pixel *this, const standard_display *display, + int for_background) +{ + 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 PNG_LIBPNG_VER < 10700 + if (!for_background && this->bit_depth < 8) + this->bit_depth = this->sample_depth = 8; +# endif + + if (this->have_tRNS) + { + /* After 1.7 the expansion of bit depth only happens if there is a + * tRNS chunk to expand at this point. + */ +# if PNG_LIBPNG_VER >= 10700 + if (!for_background && this->bit_depth < 8) + this->bit_depth = this->sample_depth = 8; +# endif + + 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; + } + 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; + } +} +#endif /* transforms that need image_pixel_add_alpha */ + +struct transform_display; +typedef struct image_transform +{ + /* The name of this transform: a string. */ + const char *name; + + /* Each transform can be disabled from the command line: */ + int enable; + + /* The global list of transforms; read only. */ + struct image_transform *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. + */ + 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)(const struct image_transform *this, + struct transform_display *that); + + /* And a callback to set the transform on the current png_read_struct: + */ + void (*set)(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)(const struct image_transform *this, image_pixel *that, + png_const_structp pp, 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, + 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; + const image_transform* transform_list; + unsigned int max_gamma_8; + + /* Local variables */ + png_byte output_colour_type; + png_byte output_bit_depth; + png_byte unpacked; + + /* 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(const image_transform *this, + transform_display *that) +{ + UNUSED(this) + UNUSED(that) +} + +static void +image_transform_set_end(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(const image_transform *this, image_pixel *that, + png_const_structp pp, const transform_display *display) +{ + const unsigned int scale = (1U<<that->sample_depth)-1; + const int sig_bits = that->sig_bits; + + 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); + + /* This is a bit bogus; really the above calculation should use the red_sBIT + * value, not sample_depth, but because libpng does png_set_shift by just + * shifting the bits we get errors if we don't do it the same way. + */ + if (sig_bits && that->red_sBIT < that->sample_depth) + that->red >>= that->sample_depth - that->red_sBIT; + + /* 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); + if (sig_bits && that->green_sBIT < that->sample_depth) + that->green >>= that->sample_depth - that->green_sBIT; + + that->blue = sample_scale(that->bluef, scale); + if (sig_bits && that->blue_sBIT < that->sample_depth) + that->blue >>= that->sample_depth - that->blue_sBIT; + + 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->alphaf = 1; /* Override this. */ + that->alphae = 0; /* It's exact ;-) */ + } + + if (sig_bits && that->alpha_sBIT < that->sample_depth) + that->alpha >>= that->sample_depth - that->alpha_sBIT; +} + +/* 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, + const image_transform *transform_list) +{ + memset(dp, 0, sizeof *dp); + + /* Standard fields */ + standard_display_init(&dp->this, &pm->this, id, do_read_interlace, + pm->use_update_info); + + /* Parameter fields */ + dp->pm = pm; + dp->transform_list = transform_list; + dp->max_gamma_8 = 16; + + /* Local variable fields */ + dp->output_colour_type = 255; /* invalid */ + dp->output_bit_depth = 255; /* invalid */ + dp->unpacked = 0; /* not unpacked */ +} + +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); + + /* If png_set_filler is in action then fake the output color type to include + * an alpha channel where appropriate. + */ + if (dp->output_bit_depth >= 8 && + (dp->output_colour_type == PNG_COLOR_TYPE_RGB || + dp->output_colour_type == PNG_COLOR_TYPE_GRAY) && dp->this.filler) + dp->output_colour_type |= 4; + + /* 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; + /* FALLTHROUGH */ + case PNG_COLOR_TYPE_GRAY: + if (dp->output_bit_depth == 1 || dp->output_bit_depth == 2 || + dp->output_bit_depth == 4) + break; + /* FALLTHROUGH */ + default: + if (dp->output_bit_depth == 8 || dp->output_bit_depth == 16) + break; + /* FALLTHROUGH */ + 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. This also + * checks for internal errors. + */ + { + 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 != 0; + 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. + */ + if (test_pixel.colour_type == PNG_COLOR_TYPE_PALETTE && + test_pixel.sample_depth != 8) /* oops - internal error! */ + png_error(pp, "pngvalid: internal: palette sample depth not 8"); + else if (dp->unpacked && test_pixel.bit_depth != 8) + png_error(pp, "pngvalid: internal: bad unpacked pixel depth"); + else if (!dp->unpacked && test_pixel.colour_type != PNG_COLOR_TYPE_PALETTE + && test_pixel.bit_depth != test_pixel.sample_depth) + { + char message[128]; + size_t pos = safecat(message, sizeof message, 0, + "internal: sample depth "); + + /* Because unless something has set 'unpacked' or the image is palette + * mapped we expect the transform to keep sample depth and bit depth + * the same. + */ + pos = safecatn(message, sizeof message, pos, test_pixel.sample_depth); + pos = safecat(message, sizeof message, pos, " expected "); + pos = safecatn(message, sizeof message, pos, test_pixel.bit_depth); + + png_error(pp, message); + } + else if (test_pixel.bit_depth != dp->output_bit_depth) + { + /* This could be a libpng error too; libpng has not produced what we + * expect for the output bit depth. + */ + char message[128]; + size_t pos = safecat(message, sizeof message, 0, + "internal: 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); + } + } +} + +static void PNGCBAPI +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_const_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, + 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 (debugonly(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); + } + + UNUSED(limit) +} + +static void +transform_image_validate(transform_display *dp, png_const_structp pp, + png_infop pi) +{ + /* Constants for the loop below: */ + const png_store* const ps = dp->this.ps; + const png_byte in_ct = dp->this.colour_type; + const png_byte in_bd = dp->this.bit_depth; + const png_uint_32 w = dp->this.w; + const png_uint_32 h = dp->this.h; + const png_byte out_ct = dp->output_colour_type; + const png_byte out_bd = dp->output_bit_depth; + const png_byte sample_depth = (png_byte)(out_ct == + PNG_COLOR_TYPE_PALETTE ? 8 : out_bd); + const png_byte red_sBIT = dp->this.red_sBIT; + const png_byte green_sBIT = dp->this.green_sBIT; + const png_byte blue_sBIT = dp->this.blue_sBIT; + const png_byte alpha_sBIT = dp->this.alpha_sBIT; + 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); + + /* use-input-precision 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. + */ + 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 calculations are at 8 bit precision, and the output actually + * consists of scaled 8-bit values, so scale .5 in 8 bits to the 16 bits: + */ + else + digitization_error = .5 * 257; + } + + for (y=0; y<h; ++y) + { + png_const_bytep 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, + NULL); + + 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 != 0; + + /* For error detection, below. */ + r = in_pixel.red; + g = in_pixel.green; + b = in_pixel.blue; + a = in_pixel.alpha; + + /* This applies the transforms to the input data, including output + * format operations which must be used when reading the output + * pixel that libpng produces. + */ + 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. in_pixel + * says whether we expect libpng to change the output format. + */ + image_pixel_init(&out_pixel, pRow, out_ct, out_bd, x, out_palette, + &in_pixel); + + /* 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 PNGCBAPI +transform_end(png_structp ppIn, png_infop pi) +{ + png_const_structp pp = ppIn; + 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, const png_uint_32 idIn, + const image_transform* transform_listIn, const char * const 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(voidcast(png_modifier*,(void*)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: */ +extern void image_transform_default_ini(const image_transform *this, + transform_display *that); /* silence GCC warnings */ + +void /* private, but almost always needed */ +image_transform_default_ini(const image_transform *this, + transform_display *that) +{ + this->next->ini(this->next, that); +} + +#ifdef PNG_READ_BACKGROUND_SUPPORTED +static int +image_transform_default_add(image_transform *this, + 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; +} +#endif + +#ifdef PNG_READ_EXPAND_SUPPORTED +/* png_set_palette_to_rgb */ +static void +image_transform_png_set_palette_to_rgb_set(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(const image_transform *this, + image_pixel *that, png_const_structp pp, + 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, + 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(const image_transform *this, + transform_display *that, png_structp pp, png_infop pi) +{ + png_set_tRNS_to_alpha(pp); + + /* If there was a tRNS chunk that would get expanded and add an alpha + * channel is_transparent must be updated: + */ + if (that->this.has_tRNS) + that->this.is_transparent = 1; + + this->next->set(this->next, that, pp, pi); +} + +static void +image_transform_png_set_tRNS_to_alpha_mod(const image_transform *this, + image_pixel *that, png_const_structp pp, + const transform_display *display) +{ +#if PNG_LIBPNG_VER < 10700 + /* LIBPNG BUG: this always forces palette images to RGB. */ + if (that->colour_type == PNG_COLOR_TYPE_PALETTE) + image_pixel_convert_PLTE(that); +#endif + + /* This effectively does an 'expand' only if there is some transparency to + * convert to an alpha channel. + */ + if (that->have_tRNS) +# if PNG_LIBPNG_VER >= 10700 + if (that->colour_type != PNG_COLOR_TYPE_PALETTE && + (that->colour_type & PNG_COLOR_MASK_ALPHA) == 0) +# endif + image_pixel_add_alpha(that, &display->this, 0/*!for background*/); + +#if PNG_LIBPNG_VER < 10700 + /* 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; + } +#endif + + this->next->mod(this->next, that, pp, display); +} + +static int +image_transform_png_set_tRNS_to_alpha_add(image_transform *this, + 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. In addition, after the bug fix in 1.7.0, there is no longer + * any action on a palette image. + */ + return +# if PNG_LIBPNG_VER >= 10700 + colour_type != PNG_COLOR_TYPE_PALETTE && +# endif + (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(const image_transform *this, + transform_display *that, png_structp pp, png_infop pi) +{ + png_set_gray_to_rgb(pp); + /* NOTE: this doesn't result in tRNS expansion. */ + this->next->set(this->next, that, pp, pi); +} + +static void +image_transform_png_set_gray_to_rgb_mod(const image_transform *this, + image_pixel *that, png_const_structp pp, + 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, 0/*!for background*/); + + /* 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, + 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(const image_transform *this, + transform_display *that, png_structp pp, png_infop pi) +{ + png_set_expand(pp); + + if (that->this.has_tRNS) + that->this.is_transparent = 1; + + this->next->set(this->next, that, pp, pi); +} + +static void +image_transform_png_set_expand_mod(const image_transform *this, + image_pixel *that, png_const_structp pp, + 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, 0/*!for background*/); + + this->next->mod(this->next, that, pp, display); +} + +static int +image_transform_png_set_expand_add(image_transform *this, + 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 + * Pre 1.7.0 LIBPNG BUG: this just does an 'expand' + */ +static void +image_transform_png_set_expand_gray_1_2_4_to_8_set( + const image_transform *this, transform_display *that, png_structp pp, + png_infop pi) +{ + png_set_expand_gray_1_2_4_to_8(pp); + /* NOTE: don't expect this to expand tRNS */ + this->next->set(this->next, that, pp, pi); +} + +static void +image_transform_png_set_expand_gray_1_2_4_to_8_mod( + const image_transform *this, image_pixel *that, png_const_structp pp, + const transform_display *display) +{ +#if PNG_LIBPNG_VER < 10700 + image_transform_png_set_expand_mod(this, that, pp, display); +#else + /* Only expand grayscale of bit depth less than 8: */ + if (that->colour_type == PNG_COLOR_TYPE_GRAY && + that->bit_depth < 8) + that->sample_depth = that->bit_depth = 8; + + this->next->mod(this->next, that, pp, display); +#endif /* 1.7 or later */ +} + +static int +image_transform_png_set_expand_gray_1_2_4_to_8_add(image_transform *this, + const image_transform **that, png_byte colour_type, png_byte bit_depth) +{ +#if PNG_LIBPNG_VER < 10700 + return image_transform_png_set_expand_add(this, that, colour_type, + bit_depth); +#else + UNUSED(bit_depth) + + this->next = *that; + *that = this; + + /* This should do nothing unless the color type is gray and the bit depth is + * less than 8: + */ + return colour_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8; +#endif /* 1.7 or later */ +} + +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(const image_transform *this, + transform_display *that, png_structp pp, png_infop pi) +{ + png_set_expand_16(pp); + + /* NOTE: prior to 1.7 libpng does SET_EXPAND as well, so tRNS is expanded. */ +# if PNG_LIBPNG_VER < 10700 + if (that->this.has_tRNS) + that->this.is_transparent = 1; +# endif + + this->next->set(this->next, that, pp, pi); +} + +static void +image_transform_png_set_expand_16_mod(const image_transform *this, + image_pixel *that, png_const_structp pp, + 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, 0/*!for background*/); + + 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, + 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(const image_transform *this, + transform_display *that, png_structp pp, png_infop pi) +{ + png_set_scale_16(pp); +# if PNG_LIBPNG_VER < 10700 + /* libpng will limit the gamma table size: */ + that->max_gamma_8 = PNG_MAX_GAMMA_8; +# endif + this->next->set(this->next, that, pp, pi); +} + +static void +image_transform_png_set_scale_16_mod(const image_transform *this, + image_pixel *that, png_const_structp pp, + 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, + 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(const image_transform *this, + transform_display *that, png_structp pp, png_infop pi) +{ + png_set_strip_16(pp); +# if PNG_LIBPNG_VER < 10700 + /* libpng will limit the gamma table size: */ + that->max_gamma_8 = PNG_MAX_GAMMA_8; +# endif + this->next->set(this->next, that, pp, pi); +} + +static void +image_transform_png_set_strip_16_mod(const image_transform *this, + image_pixel *that, png_const_structp pp, + 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!) + */ + { + 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, + 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(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(const image_transform *this, + image_pixel *that, png_const_structp pp, + 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, + 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 prior to + * 1.7.0: + * + * 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(const image_transform *this, + transform_display *that) +{ + png_modifier *pm = that->pm; + 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 + */ + 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: */ +# if PNG_LIBPNG_VER < 10700 + data.red_coefficient = 6968 / 32768.; + data.green_coefficient = 23434 / 32768.; + data.blue_coefficient = 2366 / 32768.; +# else + data.red_coefficient = .2126; + data.green_coefficient = .7152; + data.blue_coefficient = .0722; +# endif + } + + 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; + + ru = random_u32(); + 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 computations have the form: + * + * r * rc + g * gc + b * bc + * + * Each component of which is +/-1/65535 from the gamma_to_1 table + * lookup, resulting in a base error of +/-6. The gamma_from_1 + * conversion adds another +/-2 in the 16-bit case and + * +/-(1<<(15-PNG_MAX_GAMMA_8)) in the 8-bit case. + */ +# if PNG_LIBPNG_VER < 10700 + if (that->this.bit_depth < 16) + that->max_gamma_8 = PNG_MAX_GAMMA_8; +# endif + that->pm->limit += pow( + (that->this.bit_depth == 16 || that->max_gamma_8 > 14 ? + 8. : + 6. + (1<<(15-that->max_gamma_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. + * + * When DIGITIZE is set because a pre-1.7 version of libpng is being + * tested allow a bigger slack. + * + * NOTE: this number only affects the internal limit check in pngvalid, + * it has no effect on the limits applied to the libpng values. + */ +#if DIGITIZE + that->pm->limit += pow( 2.0/255, data.gamma); +#else + that->pm->limit += pow( 1.0/255, data.gamma); +#endif + } + } + + 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 && !pm->assume_16_bit_calculations) + that->pm->limit += 4E-3; + } +} + +static void +image_transform_png_set_rgb_to_gray_set(const image_transform *this, + transform_display *that, png_structp pp, png_infop pi) +{ + 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; + 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(const image_transform *this, + image_pixel *that, png_const_structp pp, + const transform_display *display) +{ + if ((that->colour_type & PNG_COLOR_MASK_COLOR) != 0) + { + double gray, err; + +# if PNG_LIBPNG_VER < 10700 + if (that->colour_type == PNG_COLOR_TYPE_PALETTE) + image_pixel_convert_PLTE(that); +# endif + + /* Image now has RGB channels... */ +# if DIGITIZE + { + png_modifier *pm = display->pm; + const unsigned int sample_depth = that->sample_depth; + const unsigned int calc_depth = (pm->assume_16_bit_calculations ? 16 : + sample_depth); + const unsigned int gamma_depth = + (sample_depth == 16 ? + display->max_gamma_8 : + (pm->assume_16_bit_calculations ? + display->max_gamma_8 : + 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!) + * + * Interval arithmetic is exact, but to implement it it must be + * possible to control the floating point implementation rounding mode. + * This cannot be done in ANSI-C, so instead I reduce the 'lo' values + * by DBL_EPSILON and increase the 'hi' values by the same. + */ +# define DD(v,d,r) (digitize(v*(1-DBL_EPSILON), d, r) * (1-DBL_EPSILON)) +# define DU(v,d,r) (digitize(v*(1+DBL_EPSILON), d, r) * (1+DBL_EPSILON)) + + r = rlo = rhi = that->redf; + rlo -= that->rede; + rlo = DD(rlo, calc_depth, 1/*round*/); + rhi += that->rede; + rhi = DU(rhi, calc_depth, 1/*round*/); + + g = glo = ghi = that->greenf; + glo -= that->greene; + glo = DD(glo, calc_depth, 1/*round*/); + ghi += that->greene; + ghi = DU(ghi, calc_depth, 1/*round*/); + + b = blo = bhi = that->bluef; + blo -= that->bluee; + blo = DD(blo, calc_depth, 1/*round*/); + bhi += that->bluee; + bhi = DU(bhi, calc_depth, 1/*round*/); + + isgray = r==g && g==b; + + if (data.gamma != 1) + { + const double power = 1/data.gamma; + const double abse = .5/(sample_depth == 16 ? 65535 : 255); + + /* If a gamma calculation is done it is done using lookup tables of + * precision gamma_depth, so the already digitized value above may + * need to be further digitized here. + */ + if (gamma_depth != calc_depth) + { + rlo = DD(rlo, gamma_depth, 0/*truncate*/); + rhi = DU(rhi, gamma_depth, 0/*truncate*/); + glo = DD(glo, gamma_depth, 0/*truncate*/); + ghi = DU(ghi, gamma_depth, 0/*truncate*/); + blo = DD(blo, gamma_depth, 0/*truncate*/); + bhi = DU(bhi, gamma_depth, 0/*truncate*/); + } + + /* 'abse' is the error in the gamma table calculation itself. */ + r = pow(r, power); + rlo = DD(pow(rlo, power)-abse, calc_depth, 1); + rhi = DU(pow(rhi, power)+abse, calc_depth, 1); + + g = pow(g, power); + glo = DD(pow(glo, power)-abse, calc_depth, 1); + ghi = DU(pow(ghi, power)+abse, calc_depth, 1); + + b = pow(b, power); + blo = DD(pow(blo, power)-abse, calc_depth, 1); + bhi = DU(pow(bhi, power)+abse, calc_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 + * 2/32768, 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; + + { + const int do_round = data.gamma != 1 || calc_depth == 16; + const double ce = 2. / 32768; + + graylo = DD(rlo * (data.red_coefficient-ce) + + glo * (data.green_coefficient-ce) + + blo * (data.blue_coefficient-ce), calc_depth, do_round); + if (graylo > gray) /* always accept the right answer */ + graylo = gray; + + grayhi = DU(rhi * (data.red_coefficient+ce) + + ghi * (data.green_coefficient+ce) + + bhi * (data.blue_coefficient+ce), calc_depth, do_round); + if (grayhi < gray) + grayhi = gray; + } + + /* And invert the gamma. */ + if (data.gamma != 1) + { + const double power = data.gamma; + + /* And this happens yet again, shifting the values once more. */ + if (gamma_depth != sample_depth) + { + rlo = DD(rlo, gamma_depth, 0/*truncate*/); + rhi = DU(rhi, gamma_depth, 0/*truncate*/); + glo = DD(glo, gamma_depth, 0/*truncate*/); + ghi = DU(ghi, gamma_depth, 0/*truncate*/); + blo = DD(blo, gamma_depth, 0/*truncate*/); + bhi = DU(bhi, gamma_depth, 0/*truncate*/); + } + + gray = pow(gray, power); + graylo = DD(pow(graylo, power), sample_depth, 1); + grayhi = DU(pow(grayhi, power), sample_depth, 1); + } + +# undef DD +# undef DU + + /* 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); + +#if !RELEASE_BUILD + /* Check that this worked: */ + if (err > 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, pm->limit, 6); + png_warning(pp, buffer); + pm->limit = err; + } +#endif /* !RELEASE_BUILD */ + } + } +# else /* !DIGITIZE */ + { + double r = that->redf; + double re = that->rede; + double g = that->greenf; + double ge = that->greene; + double b = that->bluef; + double be = that->bluee; + +# if PNG_LIBPNG_VER < 10700 + /* The true gray case involves no math in earlier versions (not + * true, there was some if gamma correction was happening too.) + */ + if (r == g && r == b) + { + gray = r; + err = re; + if (err < ge) err = ge; + if (err < be) err = be; + } + + else +# endif /* before 1.7 */ + if (data.gamma == 1) + { + /* There is no need to do the conversions to and from linear space, + * so the calculation should be a lot more accurate. There is a + * built in error in the coefficients because they only have 15 bits + * and are adjusted to make sure they add up to 32768. This + * involves a integer calculation with truncation of the form: + * + * ((int)(coefficient * 100000) * 32768)/100000 + * + * This is done to the red and green coefficients (the ones + * provided to the API) then blue is calculated from them so the + * result adds up to 32768. In the worst case this can result in + * a -1 error in red and green and a +2 error in blue. Consequently + * the worst case in the calculation below is 2/32768 error. + * + * TODO: consider fixing this in libpng by rounding the calculation + * limiting the error to 1/32768. + * + * Handling this by adding 2/32768 here avoids needing to increase + * the global error limits to take this into account.) + */ + gray = r * data.red_coefficient + g * data.green_coefficient + + b * data.blue_coefficient; + err = re * data.red_coefficient + ge * data.green_coefficient + + be * data.blue_coefficient + 2./32768 + gray * 5 * DBL_EPSILON; + } + + else + { + /* The calculation happens in linear space, and this produces much + * wider errors in the encoded space. These are handled here by + * factoring the errors in to the calculation. There are two table + * lookups in the calculation and each introduces a quantization + * error defined by the table size. + */ + png_modifier *pm = display->pm; + double in_qe = (that->sample_depth > 8 ? .5/65535 : .5/255); + double out_qe = (that->sample_depth > 8 ? .5/65535 : + (pm->assume_16_bit_calculations ? .5/(1<<display->max_gamma_8) : + .5/255)); + double rhi, ghi, bhi, grayhi; + double g1 = 1/data.gamma; + + rhi = r + re + in_qe; if (rhi > 1) rhi = 1; + r -= re + in_qe; if (r < 0) r = 0; + ghi = g + ge + in_qe; if (ghi > 1) ghi = 1; + g -= ge + in_qe; if (g < 0) g = 0; + bhi = b + be + in_qe; if (bhi > 1) bhi = 1; + b -= be + in_qe; if (b < 0) b = 0; + + r = pow(r, g1)*(1-DBL_EPSILON); rhi = pow(rhi, g1)*(1+DBL_EPSILON); + g = pow(g, g1)*(1-DBL_EPSILON); ghi = pow(ghi, g1)*(1+DBL_EPSILON); + b = pow(b, g1)*(1-DBL_EPSILON); bhi = pow(bhi, g1)*(1+DBL_EPSILON); + + /* Work out the lower and upper bounds for the gray value in the + * encoded space, then work out an average and error. Remove the + * previously added input quantization error at this point. + */ + gray = r * data.red_coefficient + g * data.green_coefficient + + b * data.blue_coefficient - 2./32768 - out_qe; + if (gray <= 0) + gray = 0; + else + { + gray *= (1 - 6 * DBL_EPSILON); + gray = pow(gray, data.gamma) * (1-DBL_EPSILON); + } + + grayhi = rhi * data.red_coefficient + ghi * data.green_coefficient + + bhi * data.blue_coefficient + 2./32768 + out_qe; + grayhi *= (1 + 6 * DBL_EPSILON); + if (grayhi >= 1) + grayhi = 1; + else + grayhi = pow(grayhi, data.gamma) * (1+DBL_EPSILON); + + err = (grayhi - gray) / 2; + gray = (grayhi + gray) / 2; + + if (err <= in_qe) + err = gray * DBL_EPSILON; + + else + err -= in_qe; + +#if !RELEASE_BUILD + /* Validate that the error is within limits (this has caused + * problems before, it's much easier to detect them here.) + */ + if (err > 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, pm->limit, 6); + png_warning(pp, buffer); + pm->limit = err; + } +#endif /* !RELEASE_BUILD */ + } + } +# endif /* !DIGITIZE */ + + 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, + 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) + * + * This ignores the gamma (at present.) +*/ +#define data ITDATA(background) +static image_pixel data; + +static void +image_transform_png_set_background_set(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 */ + int expand; + 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. + */ + R8(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; + expand = 0; /* passing in an RGB not a pixel index */ + } + + else + { + if (that->this.has_tRNS) + that->this.is_transparent = 1; + + bit_depth = that->this.bit_depth; + expand = 1; + } + + image_pixel_init(&data, random_bytes, colour_type, + bit_depth, 0/*x*/, 0/*unused: palette*/, NULL/*format*/); + + /* Extract the background colour from this image_pixel, but make sure the + * unused fields of 'back' are garbage. + */ + R8(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, expand, 0); +#else + png_set_background_fixed(pp, &back, PNG_BACKGROUND_GAMMA_FILE, expand, 0); +#endif + + this->next->set(this->next, that, pp, pi); +} + +static void +image_transform_png_set_background_mod(const image_transform *this, + image_pixel *that, png_const_structp pp, + 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, 1/*for background*/); + + /* 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 */ + +/* 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 */ +#ifdef PNG_READ_INVERT_ALPHA_SUPPORTED +/* Invert the alpha channel + * + * png_set_invert_alpha(png_structrp png_ptr) + */ +static void +image_transform_png_set_invert_alpha_set(const image_transform *this, + transform_display *that, png_structp pp, png_infop pi) +{ + png_set_invert_alpha(pp); + this->next->set(this->next, that, pp, pi); +} + +static void +image_transform_png_set_invert_alpha_mod(const image_transform *this, + image_pixel *that, png_const_structp pp, + const transform_display *display) +{ + if (that->colour_type & 4) + that->alpha_inverted = 1; + + this->next->mod(this->next, that, pp, display); +} + +static int +image_transform_png_set_invert_alpha_add(image_transform *this, + const image_transform **that, png_byte colour_type, png_byte bit_depth) +{ + UNUSED(bit_depth) + + this->next = *that; + *that = this; + + /* Only has an effect on pixels with alpha: */ + return (colour_type & 4) != 0; +} + +IT(invert_alpha); +#undef PT +#define PT ITSTRUCT(invert_alpha) + +#endif /* PNG_READ_INVERT_ALPHA_SUPPORTED */ + +/* png_set_bgr */ +#ifdef PNG_READ_BGR_SUPPORTED +/* Swap R,G,B channels to order B,G,R. + * + * png_set_bgr(png_structrp png_ptr) + * + * This only has an effect on RGB and RGBA pixels. + */ +static void +image_transform_png_set_bgr_set(const image_transform *this, + transform_display *that, png_structp pp, png_infop pi) +{ + png_set_bgr(pp); + this->next->set(this->next, that, pp, pi); +} + +static void +image_transform_png_set_bgr_mod(const image_transform *this, + image_pixel *that, png_const_structp pp, + const transform_display *display) +{ + if (that->colour_type == PNG_COLOR_TYPE_RGB || + that->colour_type == PNG_COLOR_TYPE_RGBA) + that->swap_rgb = 1; + + this->next->mod(this->next, that, pp, display); +} + +static int +image_transform_png_set_bgr_add(image_transform *this, + 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_RGB || + colour_type == PNG_COLOR_TYPE_RGBA; +} + +IT(bgr); +#undef PT +#define PT ITSTRUCT(bgr) + +#endif /* PNG_READ_BGR_SUPPORTED */ + +/* png_set_swap_alpha */ +#ifdef PNG_READ_SWAP_ALPHA_SUPPORTED +/* Put the alpha channel first. + * + * png_set_swap_alpha(png_structrp png_ptr) + * + * This only has an effect on GA and RGBA pixels. + */ +static void +image_transform_png_set_swap_alpha_set(const image_transform *this, + transform_display *that, png_structp pp, png_infop pi) +{ + png_set_swap_alpha(pp); + this->next->set(this->next, that, pp, pi); +} + +static void +image_transform_png_set_swap_alpha_mod(const image_transform *this, + image_pixel *that, png_const_structp pp, + const transform_display *display) +{ + if (that->colour_type == PNG_COLOR_TYPE_GA || + that->colour_type == PNG_COLOR_TYPE_RGBA) + that->alpha_first = 1; + + this->next->mod(this->next, that, pp, display); +} + +static int +image_transform_png_set_swap_alpha_add(image_transform *this, + 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_GA || + colour_type == PNG_COLOR_TYPE_RGBA; +} + +IT(swap_alpha); +#undef PT +#define PT ITSTRUCT(swap_alpha) + +#endif /* PNG_READ_SWAP_ALPHA_SUPPORTED */ + +/* png_set_swap */ +#ifdef PNG_READ_SWAP_SUPPORTED +/* Byte swap 16-bit components. + * + * png_set_swap(png_structrp png_ptr) + */ +static void +image_transform_png_set_swap_set(const image_transform *this, + transform_display *that, png_structp pp, png_infop pi) +{ + png_set_swap(pp); + this->next->set(this->next, that, pp, pi); +} + +static void +image_transform_png_set_swap_mod(const image_transform *this, + image_pixel *that, png_const_structp pp, + const transform_display *display) +{ + if (that->bit_depth == 16) + that->swap16 = 1; + + this->next->mod(this->next, that, pp, display); +} + +static int +image_transform_png_set_swap_add(image_transform *this, + const image_transform **that, png_byte colour_type, png_byte bit_depth) +{ + UNUSED(colour_type) + + this->next = *that; + *that = this; + + return bit_depth == 16; +} + +IT(swap); +#undef PT +#define PT ITSTRUCT(swap) + +#endif /* PNG_READ_SWAP_SUPPORTED */ + +#ifdef PNG_READ_FILLER_SUPPORTED +/* Add a filler byte to 8-bit Gray or 24-bit RGB images. + * + * png_set_filler, (png_structp png_ptr, png_uint_32 filler, int flags)); + * + * Flags: + * + * PNG_FILLER_BEFORE + * PNG_FILLER_AFTER + */ +#define data ITDATA(filler) +static struct +{ + png_uint_32 filler; + int flags; +} data; + +static void +image_transform_png_set_filler_set(const image_transform *this, + transform_display *that, png_structp pp, png_infop pi) +{ + /* Need a random choice for 'before' and 'after' as well as for the + * filler. The 'filler' value has all 32 bits set, but only bit_depth + * will be used. At this point we don't know bit_depth. + */ + data.filler = random_u32(); + data.flags = random_choice(); + + png_set_filler(pp, data.filler, data.flags); + + /* The standard display handling stuff also needs to know that + * there is a filler, so set that here. + */ + that->this.filler = 1; + + this->next->set(this->next, that, pp, pi); +} + +static void +image_transform_png_set_filler_mod(const image_transform *this, + image_pixel *that, png_const_structp pp, + const transform_display *display) +{ + if (that->bit_depth >= 8 && + (that->colour_type == PNG_COLOR_TYPE_RGB || + that->colour_type == PNG_COLOR_TYPE_GRAY)) + { + const unsigned int max = (1U << that->bit_depth)-1; + that->alpha = data.filler & max; + that->alphaf = ((double)that->alpha) / max; + that->alphae = 0; + + /* The filler has been stored in the alpha channel, we must record + * that this has been done for the checking later on, the color + * type is faked to have an alpha channel, but libpng won't report + * this; the app has to know the extra channel is there and this + * was recording in standard_display::filler above. + */ + that->colour_type |= 4; /* alpha added */ + that->alpha_first = data.flags == PNG_FILLER_BEFORE; + } + + this->next->mod(this->next, that, pp, display); +} + +static int +image_transform_png_set_filler_add(image_transform *this, + const image_transform **that, png_byte colour_type, png_byte bit_depth) +{ + this->next = *that; + *that = this; + + return bit_depth >= 8 && (colour_type == PNG_COLOR_TYPE_RGB || + colour_type == PNG_COLOR_TYPE_GRAY); +} + +#undef data +IT(filler); +#undef PT +#define PT ITSTRUCT(filler) + +/* png_set_add_alpha, (png_structp png_ptr, png_uint_32 filler, int flags)); */ +/* Add an alpha byte to 8-bit Gray or 24-bit RGB images. */ +#define data ITDATA(add_alpha) +static struct +{ + png_uint_32 filler; + int flags; +} data; + +static void +image_transform_png_set_add_alpha_set(const image_transform *this, + transform_display *that, png_structp pp, png_infop pi) +{ + /* Need a random choice for 'before' and 'after' as well as for the + * filler. The 'filler' value has all 32 bits set, but only bit_depth + * will be used. At this point we don't know bit_depth. + */ + data.filler = random_u32(); + data.flags = random_choice(); + + png_set_add_alpha(pp, data.filler, data.flags); + this->next->set(this->next, that, pp, pi); +} + +static void +image_transform_png_set_add_alpha_mod(const image_transform *this, + image_pixel *that, png_const_structp pp, + const transform_display *display) +{ + if (that->bit_depth >= 8 && + (that->colour_type == PNG_COLOR_TYPE_RGB || + that->colour_type == PNG_COLOR_TYPE_GRAY)) + { + const unsigned int max = (1U << that->bit_depth)-1; + that->alpha = data.filler & max; + that->alphaf = ((double)that->alpha) / max; + that->alphae = 0; + + that->colour_type |= 4; /* alpha added */ + that->alpha_first = data.flags == PNG_FILLER_BEFORE; + } + + this->next->mod(this->next, that, pp, display); +} + +static int +image_transform_png_set_add_alpha_add(image_transform *this, + const image_transform **that, png_byte colour_type, png_byte bit_depth) +{ + this->next = *that; + *that = this; + + return bit_depth >= 8 && (colour_type == PNG_COLOR_TYPE_RGB || + colour_type == PNG_COLOR_TYPE_GRAY); +} + +#undef data +IT(add_alpha); +#undef PT +#define PT ITSTRUCT(add_alpha) + +#endif /* PNG_READ_FILLER_SUPPORTED */ + +/* png_set_packing */ +#ifdef PNG_READ_PACK_SUPPORTED +/* Use 1 byte per pixel in 1, 2, or 4-bit depth files. + * + * png_set_packing(png_structrp png_ptr) + * + * This should only affect grayscale and palette images with less than 8 bits + * per pixel. + */ +static void +image_transform_png_set_packing_set(const image_transform *this, + transform_display *that, png_structp pp, png_infop pi) +{ + png_set_packing(pp); + that->unpacked = 1; + this->next->set(this->next, that, pp, pi); +} + +static void +image_transform_png_set_packing_mod(const image_transform *this, + image_pixel *that, png_const_structp pp, + const transform_display *display) +{ + /* The general expand case depends on what the colour type is, + * low bit-depth pixel values are unpacked into bytes without + * scaling, so sample_depth is not changed. + */ + if (that->bit_depth < 8) /* grayscale or palette */ + that->bit_depth = 8; + + this->next->mod(this->next, that, pp, display); +} + +static int +image_transform_png_set_packing_add(image_transform *this, + const image_transform **that, png_byte colour_type, png_byte bit_depth) +{ + UNUSED(colour_type) + + this->next = *that; + *that = this; + + /* Nothing should happen unless the bit depth is less than 8: */ + return bit_depth < 8; +} + +IT(packing); +#undef PT +#define PT ITSTRUCT(packing) + +#endif /* PNG_READ_PACK_SUPPORTED */ + +/* png_set_packswap */ +#ifdef PNG_READ_PACKSWAP_SUPPORTED +/* Swap pixels packed into bytes; reverses the order on screen so that + * the high order bits correspond to the rightmost pixels. + * + * png_set_packswap(png_structrp png_ptr) + */ +static void +image_transform_png_set_packswap_set(const image_transform *this, + transform_display *that, png_structp pp, png_infop pi) +{ + png_set_packswap(pp); + that->this.littleendian = 1; + this->next->set(this->next, that, pp, pi); +} + +static void +image_transform_png_set_packswap_mod(const image_transform *this, + image_pixel *that, png_const_structp pp, + const transform_display *display) +{ + if (that->bit_depth < 8) + that->littleendian = 1; + + this->next->mod(this->next, that, pp, display); +} + +static int +image_transform_png_set_packswap_add(image_transform *this, + 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(packswap); +#undef PT +#define PT ITSTRUCT(packswap) + +#endif /* PNG_READ_PACKSWAP_SUPPORTED */ + + +/* png_set_invert_mono */ +#ifdef PNG_READ_INVERT_MONO_SUPPORTED +/* Invert the gray channel + * + * png_set_invert_mono(png_structrp png_ptr) + */ +static void +image_transform_png_set_invert_mono_set(const image_transform *this, + transform_display *that, png_structp pp, png_infop pi) +{ + png_set_invert_mono(pp); + this->next->set(this->next, that, pp, pi); +} + +static void +image_transform_png_set_invert_mono_mod(const image_transform *this, + image_pixel *that, png_const_structp pp, + const transform_display *display) +{ + if (that->colour_type & 4) + that->mono_inverted = 1; + + this->next->mod(this->next, that, pp, display); +} + +static int +image_transform_png_set_invert_mono_add(image_transform *this, + const image_transform **that, png_byte colour_type, png_byte bit_depth) +{ + UNUSED(bit_depth) + + this->next = *that; + *that = this; + + /* Only has an effect on pixels with no colour: */ + return (colour_type & 2) == 0; +} + +IT(invert_mono); +#undef PT +#define PT ITSTRUCT(invert_mono) + +#endif /* PNG_READ_INVERT_MONO_SUPPORTED */ + +#ifdef PNG_READ_SHIFT_SUPPORTED +/* png_set_shift(png_structp, png_const_color_8p true_bits) + * + * The output pixels will be shifted by the given true_bits + * values. + */ +#define data ITDATA(shift) +static png_color_8 data; + +static void +image_transform_png_set_shift_set(const image_transform *this, + transform_display *that, png_structp pp, png_infop pi) +{ + /* Get a random set of shifts. The shifts need to do something + * to test the transform, so they are limited to the bit depth + * of the input image. Notice that in the following the 'gray' + * field is randomized independently. This acts as a check that + * libpng does use the correct field. + */ + const unsigned int depth = that->this.bit_depth; + + data.red = (png_byte)/*SAFE*/(random_mod(depth)+1); + data.green = (png_byte)/*SAFE*/(random_mod(depth)+1); + data.blue = (png_byte)/*SAFE*/(random_mod(depth)+1); + data.gray = (png_byte)/*SAFE*/(random_mod(depth)+1); + data.alpha = (png_byte)/*SAFE*/(random_mod(depth)+1); + + png_set_shift(pp, &data); + this->next->set(this->next, that, pp, pi); +} + +static void +image_transform_png_set_shift_mod(const image_transform *this, + image_pixel *that, png_const_structp pp, + const transform_display *display) +{ + /* Copy the correct values into the sBIT fields, libpng does not do + * anything to palette data: + */ + if (that->colour_type != PNG_COLOR_TYPE_PALETTE) + { + that->sig_bits = 1; + + /* The sBIT fields are reset to the values previously sent to + * png_set_shift according to the colour type. + * does. + */ + if (that->colour_type & 2) /* RGB channels */ + { + that->red_sBIT = data.red; + that->green_sBIT = data.green; + that->blue_sBIT = data.blue; + } + + else /* One grey channel */ + that->red_sBIT = that->green_sBIT = that->blue_sBIT = data.gray; + + that->alpha_sBIT = data.alpha; + } + + this->next->mod(this->next, that, pp, display); +} + +static int +image_transform_png_set_shift_add(image_transform *this, + 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(shift); +#undef PT +#define PT ITSTRUCT(shift) + +#endif /* PNG_READ_SHIFT_SUPPORTED */ + +#ifdef THIS_IS_THE_PROFORMA +static void +image_transform_png_set_@_set(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(const image_transform *this, + image_pixel *that, png_const_structp pp, + const transform_display *display) +{ + this->next->mod(this->next, that, pp, display); +} + +static int +image_transform_png_set_@_add(image_transform *this, + const image_transform **that, png_byte colour_type, png_byte bit_depth) +{ + this->next = *that; + *that = this; + + return 1; +} + +IT(@); +#endif + + +/* This may just be 'end' if all the transforms are disabled! */ +static image_transform *const image_transform_first = &PT; + +static void +transform_enable(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(99); + } +} + +static void +transform_disable(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(99); +} + +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(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; + } +} + +static void +perform_transform_test(png_modifier *pm) +{ + png_byte colour_type = 0; + png_byte bit_depth = 0; + unsigned int palette_number = 0; + + while (next_format(&colour_type, &bit_depth, &palette_number, pm->test_lbg, + pm->test_tRNS)) + { + 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; + 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, const png_color_16 *pointer_to_the_background_color, + double background_gamma) +{ + /* Standard fields */ + standard_display_init(&dp->this, &pm->this, id, do_read_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 prior to 1.7 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. + */ + const double sg = dp->screen_gamma; +# ifndef PNG_FLOATING_POINT_SUPPORTED + 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! + */ + const double bg = dp->background_gamma; +# ifndef PNG_FLOATING_POINT_SUPPORTED + 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 PNGCBAPI +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_const_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_const_structp pp, + int in_depth, int out_depth) +{ + 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) || + ((dp->this.colour_type == 0 || dp->this.colour_type == 2) && + dp->this.has_tRNS)) + { + vi->do_background = dp->do_background; + + if (vi->do_background != 0) + { + 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 /* Do not expect any background processing */ + 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) + { +#ifdef PNG_READ_BACKGROUND_SUPPORTED + 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; +#endif + +#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.) + */ + UNUSED(alpha) + UNUSED(background) + UNUSED(compose) + break; + } + + return input_sample; +} + +/* This API returns the encoded *input* component, in the range 0..1 */ +static double +gamma_component_validate(const char *name, const validate_info *vi, + const unsigned int id, const unsigned int od, + const double alpha /* <0 for the alpha channel itself */, + const double background /* component background value */) +{ + const unsigned int isbit = id >> vi->isbit_shift; + const unsigned int sbit_max = vi->sbit_max; + const unsigned int outmax = vi->outmax; + 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 && vi->dp->sbit) + { + /* 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. + * + * NOTE: at present because the libpng gamma table stuff has been + * changed to use a rounding algorithm to correct errors in 8-bit + * calculations the precise sbit calculation (a shift) has been + * lost. This can result in up to a +/-1 error in the presence of + * an sbit less than the bit depth. + */ +# if PNG_LIBPNG_VER < 10700 +# define SBIT_ERROR .5 +# else +# define SBIT_ERROR 1. +# endif + double tmp = (isbit - SBIT_ERROR)/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 + SBIT_ERROR)/sbit_max; + + if (tmp >= 1) + tmp = 1; + + 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) + { +# ifdef PNG_READ_BACKGROUND_SUPPORTED + case PNG_BACKGROUND_GAMMA_SCREEN: + case PNG_BACKGROUND_GAMMA_FILE: + case PNG_BACKGROUND_GAMMA_UNIQUE: + use_background = (alpha >= 0 && alpha < 1); +# endif +# ifdef PNG_READ_ALPHA_MODE_SUPPORTED + /* FALLTHROUGH */ + 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_const_structp pp, + png_infop pi) +{ + /* Get some constants derived from the input and output file formats: */ + const png_store* const ps = dp->this.ps; + const png_byte in_ct = dp->this.colour_type; + const png_byte in_bd = dp->this.bit_depth; + const png_uint_32 w = dp->this.w; + const png_uint_32 h = dp->this.h; + const size_t cbRow = dp->this.cbRow; + const png_byte out_ct = png_get_color_type(pp, pi); + 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 above. + */ + const unsigned int samples_per_pixel = (out_ct & 2U) ? 3U : 1U; + int processing; + png_uint_32 y; + const store_palette_entry *in_palette = dp->this.palette; + const int in_is_transparent = dp->this.is_transparent; + int process_tRNS; + 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; + process_tRNS = dp->this.has_tRNS && 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. */ + const unsigned int in_index = + in_ct == 3 ? sample(std, 3, in_bd, x, 0, 0, 0) : 256; + const unsigned int out_index = + out_ct == 3 ? sample(std, 3, out_bd, x, 0, 0, 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)) + { + const unsigned int input_alpha = in_ct == 3 ? + dp->this.palette[in_index].alpha : + sample(std, in_ct, in_bd, x, samples_per_pixel, 0, 0); + + 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, 0, 0); + + 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; + } + } + + else if (process_tRNS) + { + /* alpha needs to be set appropriately for this pixel, it is + * currently 1 and needs to be 0 for an input pixel which matches + * the values in tRNS. + */ + switch (in_ct) + { + case 0: /* gray */ + if (sample(std, in_ct, in_bd, x, 0, 0, 0) == + dp->this.transparent.red) + alpha = 0; + break; + + case 2: /* RGB */ + if (sample(std, in_ct, in_bd, x, 0, 0, 0) == + dp->this.transparent.red && + sample(std, in_ct, in_bd, x, 1, 0, 0) == + dp->this.transparent.green && + sample(std, in_ct, in_bd, x, 2, 0, 0) == + dp->this.transparent.blue) + alpha = 0; + break; + + default: + break; + } + } + + /* 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, 0, 0), + sample(pRow, out_ct, out_bd, x, 0, 0, 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, 0, 0), + out_ct == 3 ? out_palette[out_index].red : + sample(pRow, out_ct, out_bd, x, 0, 0, 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, 0, 0), + out_ct == 3 ? out_palette[out_index].green : + sample(pRow, out_ct, out_bd, x, 1, 0, 0), + 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, 0, 0), + out_ct == 3 ? out_palette[out_index].blue : + sample(pRow, out_ct, out_bd, x, 2, 0, 0), + 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 %lu changed", + (unsigned long)y); + + png_error(pp, msg); + } + } /* row (y) loop */ + + dp->this.ps->validated = 1; +} + +static void PNGCBAPI +gamma_end(png_structp ppIn, png_infop pi) +{ + png_const_structp pp = ppIn; + 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, const png_byte colour_typeIn, + const png_byte bit_depthIn, const int palette_numberIn, + const int interlace_typeIn, + const double file_gammaIn, const double screen_gammaIn, + const png_byte sbitIn, const int threshold_testIn, + const char *name, + const int use_input_precisionIn, const int scale16In, + const int expand16In, const int do_backgroundIn, + 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 reading 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(voidcast(png_modifier*,(void*)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; + unsigned 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! + * + * CHANGED: now test two palettes and, as a side effect, images with and + * without tRNS. + */ + while (next_format(&colour_type, &bit_depth, &palette_number, + pm->test_lbg_gamma_threshold, pm->test_tRNS)) + if (palette_number < 2) + { + 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, + const png_byte colour_type, const png_byte bit_depth, + const int palette_number, + const int interlace_type, const double file_gamma, + const double screen_gamma, const png_byte sbit, + const int use_input_precision, 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; + unsigned int palette_number = 0; + + while (next_format(&colour_type, &bit_depth, &palette_number, + pm->test_lbg_gamma_transform, pm->test_tRNS)) + { + 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 = 0, bit_depth = 0; + unsigned int npalette = 0; + + while (next_format(&colour_type, &bit_depth, &npalette, + pm->test_lbg_gamma_sbit, pm->test_tRNS)) + 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 +# if defined PNG_MAX_GAMMA_8 || PNG_LIBPNG_VER < 10700 +# define SBIT_16_TO_8 PNG_MAX_GAMMA_8 +# else +# define SBIT_16_TO_8 16 +# 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], SBIT_16_TO_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], SBIT_16_TO_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], SBIT_16_TO_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], SBIT_16_TO_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, + const png_byte colour_type, const png_byte bit_depth, + const int palette_number, + const int interlace_type, const double file_gamma, + const double screen_gamma, + const int use_input_precision, const int do_background, + 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); + + /* In earlier libpng versions, those where DIGITIZE is set, any background + * gamma correction in the expand16 case was done using 8-bit gamma + * correction tables, resulting in larger errors. To cope with those + * cases use a 16-bit background value which will handle this gamma + * correction. + */ +# if DIGITIZE + if (expand_16 && (do_background == PNG_BACKGROUND_GAMMA_UNIQUE || + do_background == PNG_BACKGROUND_GAMMA_FILE) && + fabs(bg*screen_gamma-1) > PNG_GAMMA_THRESHOLD) + { + /* The background values will be looked up in an 8-bit table to do + * the gamma correction, so only select values which are an exact + * match for the 8-bit table entries: + */ + background.red = (png_uint_16)((background.red >> 8) * 257); + background.green = (png_uint_16)((background.green >> 8) * 257); + background.blue = (png_uint_16)((background.blue >> 8) * 257); + background.gray = (png_uint_16)((background.gray >> 8) * 257); + } +# endif + } + + 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)) + { + /* Because, currently, png_set_background is always called with + * 'need_expand' false in this case and because the gamma test itself + * doesn't cause an expand to 8-bit for lower bit depths the colour must + * be reduced to the correct range. + */ + if (bit_depth < 8) + background.gray &= (png_uint_16)((1U << bit_depth)-1); + + /* 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; + unsigned int palette_number = 0; + + /* Skip the non-alpha cases - there is no setting of a transparency colour at + * present. + * + * TODO: incorrect; the palette case sets tRNS and, now RGB and gray do, + * however the palette case fails miserably so is commented out below. + */ + while (next_format(&colour_type, &bit_depth, &palette_number, + pm->test_lbg_gamma_composition, pm->test_tRNS)) + if ((colour_type & PNG_COLOR_MASK_ALPHA) != 0 +#if 0 /* TODO: FIXME */ + /*TODO: FIXME: this should work */ + || colour_type == 3 +#endif + || (colour_type != 3 && palette_number != 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) +{ + /* Use -1 to catch tests that were not actually run */ + pm->error_gray_2 = pm->error_gray_4 = pm->error_gray_8 = -1.; + pm->error_color_8 = -1.; + pm->error_indexed = -1.; + pm->error_gray_16 = pm->error_color_16 = -1.; +} + +static void +print_one(const char *leader, double err) +{ + if (err != -1.) + printf(" %s %.5f\n", leader, err); +} + +static void +summarize_gamma_errors(png_modifier *pm, png_const_charp who, int low_bit_depth, + int indexed) +{ + fflush(stderr); + + if (who) + printf("\nGamma correction with %s:\n", who); + + else + printf("\nBasic gamma correction:\n"); + + if (low_bit_depth) + { + print_one(" 2 bit gray: ", pm->error_gray_2); + print_one(" 4 bit gray: ", pm->error_gray_4); + print_one(" 8 bit gray: ", pm->error_gray_8); + print_one(" 8 bit color:", pm->error_color_8); + if (indexed) + print_one(" indexed: ", pm->error_indexed); + } + + print_one("16 bit gray: ", pm->error_gray_16); + print_one("16 bit color:", pm->error_color_16); + + fflush(stdout); +} + +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; +# ifdef PNG_READ_BACKGROUND_SUPPORTED + double maxout8 = pm->maxout8; +# endif + + /* 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) + { + if (summary) + { + fflush(stderr); + 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"); + fflush(stdout); + } + + 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) + summarize_gamma_errors(pm, 0/*who*/, 1/*low bit depth*/, 1/*indexed*/); + + if (fail(pm)) + return; + } + + /* 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, 1/*indexed*/); + + if (fail(pm)) + return; + } + +#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) + { + fflush(stderr); + printf("\nGamma 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); + fflush(stdout); + } + + if (fail(pm)) + return; + } +#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, 0/*indexed*/); + + if (fail(pm)) + return; + } +#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, 0/*indexed*/); + + if (fail(pm)) + return; + } +#endif +} +#endif /* PNG_READ_GAMMA_SUPPORTED */ +#endif /* PNG_READ_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 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(99); + } + + 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(99); + } + + 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(99); + } + + 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(99); + } + + /* 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;;) + { + /* The first two tests overflow if the pass row or column is outside + * the possible range for a 32-bit result. In fact the values should + * never be outside the range for a 31-bit result, but checking for 32 + * bits here ensures that if an app uses a bogus pass row or column + * (just so long as it fits in a 32 bit integer) it won't get a + * possibly dangerous overflow. + */ + /* First the base 0 stuff: */ + if (v < png_pass_rows(0xFFFFFFFFU, pass)) + { + 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(99); + } + } + + if (v < png_pass_cols(0xFFFFFFFFU, pass)) + { + 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(99); + } + } + + 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(99); + } + + 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(99); + } + + /* 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(99); + } + + 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(99); + } + + /* 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 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} }, +/* Fake encoding which selects just the green channel */ +/*gamma:*/ { 1.45/2.2, /* the 'Mac' gamma */ +/*red: */ { 0.716500716779386, 0.000000000000000, 0.000000000000000 }, +/*green:*/ { 0.101020574397477, 1.000000000000000, 0.051211818965388 }, +/*blue: */ { 0.146774385252705, 0.000000000000000, 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, char **argv) +{ + int summary = 1; /* Print the error summary at the end */ + int memstats = 0; /* Print memory statistics at the end */ + + /* Create the given output file on success: */ + const char *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); + + gnu_volatile(summary) + gnu_volatile(memstats) + gnu_volatile(touch) + + /* 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; + + /* Default assume_16_bit_calculations appropriately; this tells the checking + * code that 16-bit arithmetic is used for 8-bit samples when it would make a + * difference. + */ + pm.assume_16_bit_calculations = PNG_LIBPNG_VER >= 10700; + + /* Currently 16 bit expansion happens at the end of the pipeline, so the + * calculations are done in the input bit depth not the output. + * + * TODO: fix this + */ + pm.calculations_use_input_precision = 1U; + + /* Store the test gammas */ + pm.gammas = gammas; + pm.ngammas = ARRAY_SIZE(gammas); + pm.ngamma_tests = 0; /* default to off */ + + /* Low bit depth gray images don't do well in the gamma tests, until + * this is fixed turn them off for some gamma cases: + */ +# ifdef PNG_WRITE_tRNS_SUPPORTED + pm.test_tRNS = 1; +# endif + pm.test_lbg = PNG_LIBPNG_VER >= 10600; + pm.test_lbg_gamma_threshold = 1; + pm.test_lbg_gamma_transform = PNG_LIBPNG_VER >= 10600; + pm.test_lbg_gamma_sbit = 1; + pm.test_lbg_gamma_composition = PNG_LIBPNG_VER >= 10700; + + /* And the test encodings */ + pm.encodings = test_encodings; + pm.nencodings = ARRAY_SIZE(test_encodings); + +# if PNG_LIBPNG_VER < 10700 + pm.sbitlow = 8U; /* because libpng doesn't do sBIT below 8! */ +# else + pm.sbitlow = 1U; +# endif + + /* 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 in + * releases up to 1.6.0. + * + * TODO: review this + */ + pm.use_input_precision_16to8 = 1U; + pm.use_input_precision_sbit = 1U; /* because libpng now rounds sBIT */ + + /* 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 = 1./255; /* +/-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 =1./65535;/* +/-1 in 16 bits for compose errors */ +# if PNG_LIBPNG_VER < 10700 + pm.maxcalcG = 1./((1<<PNG_MAX_GAMMA_8)-1); +# else + pm.maxcalcG = 1./((1<<16)-1); +# endif + + /* 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 || + strcmp(*argv, "--strict") == 0) + pm.this.treat_warnings_as_errors = 1; /* NOTE: this is the default! */ + + else if (strcmp(*argv, "--nostrict") == 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; /* composition */ + 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, "--low-depth-gray") == 0) + pm.test_lbg = pm.test_lbg_gamma_threshold = + pm.test_lbg_gamma_transform = pm.test_lbg_gamma_sbit = + pm.test_lbg_gamma_composition = 1; + + else if (strcmp(*argv, "--nolow-depth-gray") == 0) + pm.test_lbg = pm.test_lbg_gamma_threshold = + pm.test_lbg_gamma_transform = pm.test_lbg_gamma_sbit = + pm.test_lbg_gamma_composition = 0; + +# ifdef PNG_WRITE_tRNS_SUPPORTED + else if (strcmp(*argv, "--tRNS") == 0) + pm.test_tRNS = 1; +# endif + + else if (strcmp(*argv, "--notRNS") == 0) + pm.test_tRNS = 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) + { +# if CAN_WRITE_INTERLACE + pm.interlace_type = PNG_INTERLACE_ADAM7; +# else /* !CAN_WRITE_INTERLACE */ + fprintf(stderr, "pngvalid: no write interlace support\n"); + return SKIP; +# endif /* !CAN_WRITE_INTERLACE */ + } + + else if (strcmp(*argv, "--use-input-precision") == 0) + pm.use_input_precision = 1U; + + else if (strcmp(*argv, "--use-calculation-precision") == 0) + pm.use_input_precision = 0; + + else if (strcmp(*argv, "--calculations-use-input-precision") == 0) + pm.calculations_use_input_precision = 1U; + + else if (strcmp(*argv, "--assume-16-bit-calculations") == 0) + pm.assume_16_bit_calculations = 1U; + + 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(99); + } + + 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; + +#ifdef PNG_SET_OPTION_SUPPORTED + else if (strncmp(*argv, "--option=", 9) == 0) + { + /* Syntax of the argument is <option>:{on|off} */ + const char *arg = 9+*argv; + unsigned char option=0, setting=0; + +#ifdef PNG_ARM_NEON + if (strncmp(arg, "arm-neon:", 9) == 0) + option = PNG_ARM_NEON, arg += 9; + + else +#endif +#ifdef PNG_EXTENSIONS + if (strncmp(arg, "extensions:", 11) == 0) + option = PNG_EXTENSIONS, arg += 11; + + else +#endif +#ifdef PNG_MAXIMUM_INFLATE_WINDOW + if (strncmp(arg, "max-inflate-window:", 19) == 0) + option = PNG_MAXIMUM_INFLATE_WINDOW, arg += 19; + + else +#endif + { + fprintf(stderr, "pngvalid: %s: %s: unknown option\n", *argv, arg); + exit(99); + } + + if (strcmp(arg, "off") == 0) + setting = PNG_OPTION_OFF; + + else if (strcmp(arg, "on") == 0) + setting = PNG_OPTION_ON; + + else + { + fprintf(stderr, + "pngvalid: %s: %s: unknown setting (use 'on' or 'off')\n", + *argv, arg); + exit(99); + } + + pm.this.options[pm.this.noptions].option = option; + pm.this.options[pm.this.noptions++].setting = setting; + } +#endif /* PNG_SET_OPTION_SUPPORTED */ + + else + { + fprintf(stderr, "pngvalid: %s: unknown argument\n", *argv); + exit(99); + } + + 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); + + /* Perform the standard and gamma tests. */ + if (pm.test_standard) + { + perform_interlace_macro_validation(); + perform_formatting_test(&pm.this); +# ifdef PNG_READ_SUPPORTED + perform_standard_test(&pm); +# endif + perform_error_test(&pm); + } + + /* Various oddly sized images: */ + if (pm.test_size) + { + make_size_images(&pm.this); +# ifdef PNG_READ_SUPPORTED + perform_size_test(&pm); +# endif + } + +#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); + } + } + + else + { + fprintf(stderr, "%s: open failed\n", touch); + exit(1); + } + } + + /* This is required because some very minimal configurations do not use it: + */ + UNUSED(fail) + return 0; +} +#else /* write or low level APIs not supported */ +int main(void) +{ + fprintf(stderr, + "pngvalid: no low level write support in libpng, all tests skipped\n"); + /* So the test is skipped: */ + return SKIP; +} +#endif |