/* pngvalid.c - validate libpng by constructing then reading png files. * * Last changed in libpng 1.6.29 [(PENDING RELEASE)] * 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 #include #if defined(HAVE_CONFIG_H) && !defined(PNG_NO_CONFIG_H) # include #endif #ifdef HAVE_FEENABLEEXCEPT /* from config.h, if included */ # include #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 #else # include "../../png.h" #endif #ifdef PNG_ZLIB_HEADER # include PNG_ZLIB_HEADER #else # include /* 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)) #define PNG_PASS_COLS(width, pass) (((width)+(((1<>PNG_PASS_COL_SHIFT(pass)) #define PNG_ROW_FROM_PASS_ROW(yIn, pass) \ (((yIn)<>(((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 /* For floating point constants */ #include /* For malloc */ #include /* For memcpy, memset */ #include /* 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 #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(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> (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<> 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; yimage; 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; optnoptions; ++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; optnoptions; ++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<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 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<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 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 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 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<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; iis_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 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; yh; ++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<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<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<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<green_sBIT)-1)); that->bluee += 1./(2*((1U<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<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; /*FALL THROUGH*/ case PNG_COLOR_TYPE_GRAY: if (dp->output_bit_depth == 1 || dp->output_bit_depth == 2 || dp->output_bit_depth == 4) break; /*FALL THROUGH*/ default: if (dp->output_bit_depth == 8 || dp->output_bit_depth == 16) break; /*FALL THROUGH*/ error: { char message[128]; size_t pos; pos = safecat(message, sizeof message, 0, "invalid final bit depth: colour type("); pos = safecatn(message, sizeof message, pos, dp->output_colour_type); pos = safecat(message, sizeof message, pos, ") with bit depth: "); pos = safecatn(message, sizeof message, pos, dp->output_bit_depth); png_error(pp, message); } } /* Use a test pixel to check that the output agrees with what we expect - * this avoids running the whole test if the output is unexpected. 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< 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; ythis.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<pm->limit + 1./(2*((1U<pm->limit + 1./(2*((1U<pm->limit + 1./(2*((1U<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<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<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); /*FALL THROUGH*/ # endif # ifdef PNG_READ_ALPHA_MODE_SUPPORTED case ALPHA_MODE_OFFSET + PNG_ALPHA_STANDARD: case ALPHA_MODE_OFFSET + PNG_ALPHA_BROKEN: case ALPHA_MODE_OFFSET + PNG_ALPHA_OPTIMIZED: # endif /* ALPHA_MODE_SUPPORTED */ do_compose = (alpha > 0 && alpha < 1); use_input = (alpha != 0); break; default: break; } /* Check the 'compose' flag */ if (compose != do_compose) png_error(vi->pp, "internal error (compose)"); /* 'name' is the component name */ pos = safecat(msg, sizeof msg, pos, name); pos = safecat(msg, sizeof msg, pos, "("); pos = safecatn(msg, sizeof msg, pos, id); if (use_input || pass != 0/*logging*/) { if (isbit != id) { /* sBIT has reduced the precision of the input: */ pos = safecat(msg, sizeof msg, pos, ", sbit("); pos = safecatn(msg, sizeof msg, pos, vi->sbit); pos = safecat(msg, sizeof msg, pos, "): "); pos = safecatn(msg, sizeof msg, pos, isbit); } pos = safecat(msg, sizeof msg, pos, "/"); /* The output is either "id/max" or "id sbit(sbit): isbit/max" */ pos = safecatn(msg, sizeof msg, pos, vi->sbit_max); } pos = safecat(msg, sizeof msg, pos, ")"); /* A component may have been multiplied (in linear space) by the * alpha value, 'compose' says whether this is relevant. */ if (compose || pass != 0) { /* If any form of composition is being done report our * calculated linear value here (the code above doesn't record * the input value before composition is performed, so what * gets reported is the value after composition.) */ if (use_input || pass != 0) { if (vi->file_inverse > 0) { pos = safecat(msg, sizeof msg, pos, "^"); pos = safecatd(msg, sizeof msg, pos, vi->file_inverse, 2); } else pos = safecat(msg, sizeof msg, pos, "[linear]"); pos = safecat(msg, sizeof msg, pos, "*(alpha)"); pos = safecatd(msg, sizeof msg, pos, alpha, precision); } /* Now record the *linear* background value if it was used * (this function is not passed the original, non-linear, * value but it is contained in the test name.) */ if (use_background) { pos = safecat(msg, sizeof msg, pos, use_input ? "+" : " "); pos = safecat(msg, sizeof msg, pos, "(background)"); pos = safecatd(msg, sizeof msg, pos, background, precision); pos = safecat(msg, sizeof msg, pos, "*"); pos = safecatd(msg, sizeof msg, pos, 1-alpha, precision); } } /* Report the calculated value (input_sample) and the linearized * libpng value (output) unless this is just a component gamma * correction. */ if (compose || alpha < 0 || pass != 0) { pos = safecat(msg, sizeof msg, pos, pass != 0 ? " =\n\t" : " = "); pos = safecatd(msg, sizeof msg, pos, input_sample, precision); pos = safecat(msg, sizeof msg, pos, " (libpng: "); pos = safecatd(msg, sizeof msg, pos, output, precision); pos = safecat(msg, sizeof msg, pos, ")"); /* Finally report the output gamma encoding, if any. */ if (output_is_encoded) { pos = safecat(msg, sizeof msg, pos, " ^"); pos = safecatd(msg, sizeof msg, pos, vi->screen_inverse, 2); pos = safecat(msg, sizeof msg, pos, "(to screen) ="); } else pos = safecat(msg, sizeof msg, pos, " [screen is linear] ="); } if ((!compose && alpha >= 0) || pass != 0) { if (pass != 0) /* logging */ pos = safecat(msg, sizeof msg, pos, "\n\t[overall:"); /* This is the non-composition case, the internal linear * values are irrelevant (though the log below will reveal * them.) Output a much shorter warning/error message and report * the overall gamma correction. */ if (vi->gamma_correction > 0) { pos = safecat(msg, sizeof msg, pos, " ^"); pos = safecatd(msg, sizeof msg, pos, vi->gamma_correction, 2); pos = safecat(msg, sizeof msg, pos, "(gamma correction) ="); } else pos = safecat(msg, sizeof msg, pos, " [no gamma correction] ="); if (pass != 0) pos = safecat(msg, sizeof msg, pos, "]"); } /* This is our calculated encoded_sample which should (but does * not) match od: */ pos = safecat(msg, sizeof msg, pos, pass != 0 ? "\n\t" : " "); pos = safecatd(msg, sizeof msg, pos, is_lo, 1); pos = safecat(msg, sizeof msg, pos, " < "); pos = safecatd(msg, sizeof msg, pos, encoded_sample, 1); pos = safecat(msg, sizeof msg, pos, " (libpng: "); pos = safecatn(msg, sizeof msg, pos, od); pos = safecat(msg, sizeof msg, pos, ")"); pos = safecat(msg, sizeof msg, pos, "/"); pos = safecatn(msg, sizeof msg, pos, outmax); pos = safecat(msg, sizeof msg, pos, " < "); pos = safecatd(msg, sizeof msg, pos, is_hi, 1); if (pass == 0) /* The error condition */ { # ifdef PNG_WARNINGS_SUPPORTED png_warning(vi->pp, msg); # else store_warning(vi->pp, msg); # endif } else /* logging this value */ store_verbose(&vi->dp->pm->this, vi->pp, pass, msg); } } } return i; } static void gamma_image_validate(gamma_display *dp, png_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<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; ythis.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; ingamma_tests; ++i) for (j=0; jngamma_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<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; ingamma_tests; ++i) { unsigned int j; for (j=0; jngamma_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; ingamma_tests; ++i) { for (j=0; jngamma_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; ingamma_tests; ++i) for (j=0; jngamma_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<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