diff options
Diffstat (limited to 'Build/source/libs/libpng/libpng-1.6.16/contrib/tools/pngfix.c')
-rw-r--r-- | Build/source/libs/libpng/libpng-1.6.16/contrib/tools/pngfix.c | 4048 |
1 files changed, 0 insertions, 4048 deletions
diff --git a/Build/source/libs/libpng/libpng-1.6.16/contrib/tools/pngfix.c b/Build/source/libs/libpng/libpng-1.6.16/contrib/tools/pngfix.c deleted file mode 100644 index 65422f600c2..00000000000 --- a/Build/source/libs/libpng/libpng-1.6.16/contrib/tools/pngfix.c +++ /dev/null @@ -1,4048 +0,0 @@ -/* pngfix.c - * - * Copyright (c) 2014 John Cunningham Bowler - * - * Last changed in libpng 1.6.14 [October 23, 2014] - * - * This code is released under the libpng license. - * For conditions of distribution and use, see the disclaimer - * and license in png.h - * - * Tool to check and fix the zlib inflate 'too far back' problem. - * See the usage message for more information. - */ -#include <stdlib.h> -#include <stdio.h> -#include <string.h> -#include <ctype.h> -#include <limits.h> -#include <errno.h> -#include <assert.h> - -#define implies(x,y) assert(!(x) || (y)) - -#ifdef __GNUC__ - /* This is used to fix the error: - * - * pngfix.c: - * In function 'zlib_advance': - * pngfix.c:181:13: error: assuming signed overflow does not - * occur when simplifying conditional to constant [-Werror=strict-overflow] - */ -# define FIX_GCC volatile -#else -# define FIX_GCC -#endif - -#define PROGRAM_NAME "pngfix" - -/* Define the following to use this program against your installed libpng, - * rather than the one being built here: - */ -#ifdef PNG_FREESTANDING_TESTS -# include <png.h> -#else -# include "../../png.h" -#endif - -#if PNG_LIBPNG_VER < 10603 /* 1.6.3 */ -# error "pngfix will not work with libpng prior to 1.6.3" -#endif - -#ifdef PNG_SETJMP_SUPPORTED -#include <setjmp.h> - -#if defined(PNG_READ_SUPPORTED) && defined(PNG_EASY_ACCESS_SUPPORTED) -/* zlib.h defines the structure z_stream, an instance of which is included - * in this structure and is required for decompressing the LZ compressed - * data in PNG files. - */ -#ifndef ZLIB_CONST - /* We must ensure that zlib uses 'const' in declarations. */ -# define ZLIB_CONST -#endif -#include <zlib.h> -#ifdef const - /* zlib.h sometimes #defines const to nothing, undo this. */ -# undef const -#endif - -/* zlib.h has mediocre z_const use before 1.2.6, this stuff is for compatibility - * with older builds. - */ -#if ZLIB_VERNUM < 0x1260 -# define PNGZ_MSG_CAST(s) png_constcast(char*,s) -# define PNGZ_INPUT_CAST(b) png_constcast(png_bytep,b) -#else -# define PNGZ_MSG_CAST(s) (s) -# define PNGZ_INPUT_CAST(b) (b) -#endif - -#ifndef PNG_MAXIMUM_INFLATE_WINDOW -# error "pngfix not supported in this libpng version" -#endif - -#if ZLIB_VERNUM >= 0x1240 - -/* Copied from pngpriv.h */ -#ifdef __cplusplus -# define png_voidcast(type, value) static_cast<type>(value) -# define png_constcast(type, value) const_cast<type>(value) -# define png_aligncast(type, value) \ - static_cast<type>(static_cast<void*>(value)) -# define png_aligncastconst(type, value) \ - static_cast<type>(static_cast<const void*>(value)) -#else -# define png_voidcast(type, value) (value) -# define png_constcast(type, value) ((type)(value)) -# define png_aligncast(type, value) ((void*)(value)) -# define png_aligncastconst(type, value) ((const void*)(value)) -#endif /* __cplusplus */ - -#if PNG_LIBPNG_VER < 10700 -/* Chunk tags (copied from pngpriv.h) */ -#define PNG_32b(b,s) ((png_uint_32)(b) << (s)) -#define PNG_U32(b1,b2,b3,b4) \ - (PNG_32b(b1,24) | PNG_32b(b2,16) | PNG_32b(b3,8) | PNG_32b(b4,0)) - -/* Constants for known chunk types. */ -#define png_IDAT PNG_U32( 73, 68, 65, 84) -#define png_IEND PNG_U32( 73, 69, 78, 68) -#define png_IHDR PNG_U32( 73, 72, 68, 82) -#define png_PLTE PNG_U32( 80, 76, 84, 69) -#define png_bKGD PNG_U32( 98, 75, 71, 68) -#define png_cHRM PNG_U32( 99, 72, 82, 77) -#define png_fRAc PNG_U32(102, 82, 65, 99) /* registered, not defined */ -#define png_gAMA PNG_U32(103, 65, 77, 65) -#define png_gIFg PNG_U32(103, 73, 70, 103) -#define png_gIFt PNG_U32(103, 73, 70, 116) /* deprecated */ -#define png_gIFx PNG_U32(103, 73, 70, 120) -#define png_hIST PNG_U32(104, 73, 83, 84) -#define png_iCCP PNG_U32(105, 67, 67, 80) -#define png_iTXt PNG_U32(105, 84, 88, 116) -#define png_oFFs PNG_U32(111, 70, 70, 115) -#define png_pCAL PNG_U32(112, 67, 65, 76) -#define png_pHYs PNG_U32(112, 72, 89, 115) -#define png_sBIT PNG_U32(115, 66, 73, 84) -#define png_sCAL PNG_U32(115, 67, 65, 76) -#define png_sPLT PNG_U32(115, 80, 76, 84) -#define png_sRGB PNG_U32(115, 82, 71, 66) -#define png_sTER PNG_U32(115, 84, 69, 82) -#define png_tEXt PNG_U32(116, 69, 88, 116) -#define png_tIME PNG_U32(116, 73, 77, 69) -#define png_tRNS PNG_U32(116, 82, 78, 83) -#define png_zTXt PNG_U32(122, 84, 88, 116) -#endif - -/* The 8 byte signature as a pair of 32 bit quantities */ -#define sig1 PNG_U32(137, 80, 78, 71) -#define sig2 PNG_U32( 13, 10, 26, 10) - -/* Is the chunk critical? */ -#define CRITICAL(chunk) (((chunk) & PNG_U32(32,0,0,0)) == 0) - -/* Is it safe to copy? */ -#define SAFE_TO_COPY(chunk) (((chunk) & PNG_U32(0,0,0,32)) != 0) - -/* Fix ups for builds with limited read support */ -#ifndef PNG_ERROR_TEXT_SUPPORTED -# define png_error(a,b) png_err(a) -#endif - -/********************************* UTILITIES **********************************/ -/* UNREACHED is a value to cause an assert to fail. Because of the way the - * assert macro is written the string "UNREACHED" is produced in the error - * message. - */ -#define UNREACHED 0 - -/* 80-bit number handling - a PNG image can be up to (2^31-1)x(2^31-1) 8 byte - * (16-bit RGBA) pixels in size; that's less than 2^65 bytes or 2^68 bits, so - * arithmetic of 80-bit numbers is sufficient. This representation uses an - * arbitrary length array of png_uint_16 digits (0..65535). The representation - * is little endian. - * - * The arithmetic functions take zero to two uarb values together with the - * number of digits in those values and write the result to the given uarb - * (always the first argument) returning the number of digits in the result. - * If the result is negative the return value is also negative (this would - * normally be an error). - */ -typedef png_uint_16 udigit; /* A 'unum' is an array of these */ -typedef png_uint_16p uarb; -typedef png_const_uint_16p uarbc; - -#define UDIGITS(unum) ((sizeof unum)/(sizeof (udigit)) - /* IMPORTANT: only apply this to an array, applied to a pointer the result - * will typically be '2', which is not useful. - */ - -static int -uarb_set(uarb result, png_alloc_size_t val) - /* Set (initialize) 'result' to 'val'. The size required for 'result' must - * be determined by the caller from a knowledge of the maximum for 'val'. - */ -{ - int ndigits = 0; - - while (val > 0) - { - result[ndigits++] = (png_uint_16)(val & 0xffff); - val >>= 16; - } - - return ndigits; -} - -static int -uarb_copy(uarb to, uarb from, int idigits) - /* Copy a uarb, may reduce the digit count */ -{ - int d, odigits; - - for (d=odigits=0; d<idigits; ++d) - if ((to[d] = from[d]) != 0) - odigits = d+1; - - return odigits; -} - -static int -uarb_inc(uarb num, int in_digits, png_int_32 add) - /* This is a signed 32-bit add, except that to avoid overflow the value added - * or subtracted must be no more than 2^31-65536. A negative result - * indicates a negative number (which is an error below). The size of - * 'num' should be max(in_digits+1,2) for arbitrary 'add' but can be just - * in_digits+1 if add is known to be in the range -65535..65535. - */ -{ - FIX_GCC int out_digits = 0; - - while (out_digits < in_digits) - { - add += num[out_digits]; - num[out_digits++] = (png_uint_16)(add & 0xffff); - add >>= 16; - } - - while (add != 0 && add != (-1)) - { - num[out_digits++] = (png_uint_16)(add & 0xffff); - add >>= 16; - } - - if (add == 0) - { - while (out_digits > 0 && num[out_digits-1] == 0) - --out_digits; - return out_digits; /* may be 0 */ - } - - else /* negative result */ - { - while (out_digits > 1 && num[out_digits-1] == 0xffff) - --out_digits; - - return -out_digits; - } -} - -static int -uarb_add32(uarb num, int in_digits, png_uint_32 add) - /* As above but this works with any 32-bit value and only does 'add' */ -{ - if (in_digits > 0) - { - in_digits = uarb_inc(num, in_digits, add & 0xffff); - return uarb_inc(num+1, in_digits-1, add >> 16)+1; - } - - return uarb_set(num, add); -} - -static int -uarb_mult_digit(uarb acc, int a_digits, uarb num, FIX_GCC int n_digits, - png_uint_16 val) - /* Primitive one-digit multiply - 'val' must be 0..65535. Note that this - * primitive is a multiply and accumulate - the result of *num * val is added - * to *acc. - * - * This is a one-digit multiply, so the product may be up to one digit longer - * than 'num', however the add to 'acc' means that the caller must ensure - * that 'acc' is at least one digit longer than this *and* at least one digit - * longer than the current length of 'acc'. (Or the caller must otherwise - * ensure 'adigits' is adequate from knowledge of the values.) - */ -{ - /* The digits in *acc, *num and val are in the range 0..65535, so the - * result below is at most (65535*65535)+2*65635 = 65535*(65535+2), which is - * exactly 0xffffffff. - */ - if (val > 0 && n_digits > 0) /* Else the product is 0 */ - { - png_uint_32 carry = 0; - int out_digits = 0; - - while (out_digits < n_digits || carry > 0) - { - if (out_digits < a_digits) - carry += acc[out_digits]; - - if (out_digits < n_digits) - carry += (png_uint_32)num[out_digits] * val; - - acc[out_digits++] = (png_uint_16)(carry & 0xffff); - carry >>= 16; - } - - /* So carry is 0 and all the input digits have been consumed. This means - * that it is possible to skip any remaining digits in acc. - */ - if (out_digits > a_digits) - return out_digits; - } - - return a_digits; -} - -static int -uarb_mult32(uarb acc, int a_digits, uarb num, int n_digits, png_uint_32 val) - /* calculate acc += num * val, 'val' may be any 32-bit value, 'acc' and 'num' - * may be any value, returns the number of digits in 'acc'. - */ -{ - if (n_digits > 0 && val > 0) - { - a_digits = uarb_mult_digit(acc, a_digits, num, n_digits, - (png_uint_16)(val & 0xffff)); - - /* Because n_digits and val are >0 the following must be true: */ - assert(a_digits > 0); - - val >>= 16; - if (val > 0) - a_digits = uarb_mult_digit(acc+1, a_digits-1, num, n_digits, - (png_uint_16)val) + 1; - } - - return a_digits; -} - -static int -uarb_shift(uarb inout, int ndigits, unsigned int right_shift) - /* Shift inout right by right_shift bits, right_shift must be in the range - * 1..15 - */ -{ - FIX_GCC int i = ndigits; - png_uint_16 carry = 0; - - assert(right_shift >= 1 && right_shift <= 15); - - while (--i >= 0) - { - png_uint_16 temp = (png_uint_16)(carry | (inout[i] >> right_shift)); - - /* Bottom bits to top bits of carry */ - carry = (png_uint_16)((inout[i] << (16-right_shift)) & 0xffff); - - inout[i] = temp; - - /* The shift may reduce ndigits */ - if (i == ndigits-1 && temp == 0) - ndigits = i; - } - - return ndigits; -} - -static int -uarb_cmp(uarb a, int adigits, uarb b, int bdigits) - /* Return -1/0/+1 according as a<b/a==b/a>b */ -{ - if (adigits < bdigits) - return -1; - - if (adigits > bdigits) - return 1; - - while (adigits-- > 0) - if (a[adigits] < b[adigits]) - return -1; - - else if (a[adigits] > b[adigits]) - return 1; - - return 0; -} - -#if 0 /*UNUSED*/ -static int -uarb_eq32(uarb num, int digits, png_uint_32 val) - /* Return true if the uarb is equal to 'val' */ -{ - switch (digits) - { - case 0: return val == 0; - case 1: return val == num[0]; - case 2: return (val & 0xffff) == num[0] && (val >> 16) == num[1]; - default: return 0; - } -} -#endif - -static void -uarb_printx(uarb num, int digits, FILE *out) - /* Print 'num' as a hexadecimal number (easier than decimal!) */ -{ - while (digits > 0) - if (num[--digits] > 0) - { - fprintf(out, "0x%x", num[digits]); - - while (digits > 0) - fprintf(out, "%.4x", num[--digits]); - } - - else if (digits == 0) /* the number is 0 */ - fputs("0x0", out); -} - -static void -uarb_print(uarb num, int digits, FILE *out) - /* Prints 'num' as a decimal if it will fit in an unsigned long, else as a - * hexadecimal number. Notice that the results vary for images over 4GByte - * in a system dependent way, and the hexadecimal form doesn't work very well - * in awk script input. - * - * - * TODO: write uarb_div10 - */ -{ - if (digits * sizeof (udigit) > sizeof (unsigned long)) - uarb_printx(num, digits, out); - - else - { - unsigned long n = 0; - - while (digits > 0) - n = (n << 16) + num[--digits]; - - fprintf(out, "%lu", n); - } -} - -/* 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.) - * - * (Copied from contrib/libtests/pngvalid.c) - */ -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 = png_voidcast(png_bytep, pv); - - /* There are thirty-three bits; the next bit in the sequence is bit-33 XOR - * bit-20. The top 1 bit is in u1, the bottom 32 are in u0. - */ - size_t i; - for (i=0; i<size; ++i) - { - /* First generate 8 new bits then shift them in at the end. */ - png_uint_32 u = ((u0 >> (20-8)) ^ ((u1 << 7) | (u0 >> (32-7)))) & 0xff; - u1 <<= 8; - u1 |= u0 >> 24; - u0 <<= 8; - u0 |= u; - *bytes++ = (png_byte)u; - } - - seed[0] = u0; - seed[1] = u1; -} - -/* Clear an object to a random value. */ -static void -clear(void *pv, size_t size) -{ - static png_uint_32 clear_seed[2] = { 0x12345678, 0x9abcdef0 }; - make_random_bytes(clear_seed, pv, size); -} - -#define CLEAR(object) clear(&(object), sizeof (object)) - -/* Copied from unreleased 1.7 code. - * - * CRC checking uses a local pre-built implementation of the Ethernet CRC32. - * This is to avoid a function call to the zlib DLL and to optimize the - * byte-by-byte case. - */ -static png_uint_32 crc_table[256] = -{ - 0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, - 0x706af48f, 0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, - 0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, - 0x90bf1d91, 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de, - 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7, 0x136c9856, - 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9, - 0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, - 0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, - 0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, - 0x45df5c75, 0xdcd60dcf, 0xabd13d59, 0x26d930ac, 0x51de003a, - 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599, - 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924, - 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, - 0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, - 0x9fbfe4a5, 0xe8b8d433, 0x7807c9a2, 0x0f00f934, 0x9609a88e, - 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01, - 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed, - 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950, - 0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, - 0xfbd44c65, 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, - 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, - 0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5, - 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa, 0xbe0b1010, - 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f, - 0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, - 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, - 0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615, - 0x73dc1683, 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8, - 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1, 0xf00f9344, - 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb, - 0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, - 0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, - 0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, - 0xa6bc5767, 0x3fb506dd, 0x48b2364b, 0xd80d2bda, 0xaf0a1b4c, - 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef, - 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236, - 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, - 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, - 0x2cd99e8b, 0x5bdeae1d, 0x9b64c2b0, 0xec63f226, 0x756aa39c, - 0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713, - 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b, - 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242, - 0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, - 0x18b74777, 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, - 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45, 0xa00ae278, - 0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7, - 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc, 0x40df0b66, - 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9, - 0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, - 0xcdd70693, 0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, - 0x5d681b02, 0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, - 0x2d02ef8d -}; - -/* The CRC calculated here *IS* conditioned, the corresponding value used by - * zlib and the result value is obtained by XORing with CRC_INIT, which is also - * the first value that must be passed in (for the first byte) to crc_one_byte. - */ -#define CRC_INIT 0xffffffff - -static png_uint_32 -crc_one_byte(png_uint_32 crc, int b) -{ - return crc_table[(crc ^ b) & 0xff] ^ (crc >> 8); -} - -static png_uint_32 -crc_init_4(png_uint_32 value) -{ - /* This is an alternative to the algorithm used in zlib, which requires four - * separate tables to parallelize the four byte operations, it only works for - * a CRC of the first four bytes of the stream, but this is what happens in - * the parser below where length+chunk-name is read and chunk-name used to - * initialize the CRC. Notice that the calculation here avoids repeated - * conditioning (xor with 0xffffffff) by storing the conditioned value. - */ - png_uint_32 crc = crc_table[(~value >> 24)] ^ 0xffffff; - - crc = crc_table[(crc ^ (value >> 16)) & 0xff] ^ (crc >> 8); - crc = crc_table[(crc ^ (value >> 8)) & 0xff] ^ (crc >> 8); - return crc_table[(crc ^ value) & 0xff] ^ (crc >> 8); -} - -static int -chunk_type_valid(png_uint_32 c) - /* Bit whacking approach to chunk name validation that is intended to avoid - * branches. The cost is that it uses a lot of 32-bit constants, which might - * be bad on some architectures. - */ -{ - png_uint_32 t; - - /* Remove bit 5 from all but the reserved byte; this means every - * 8-bit unit must be in the range 65-90 to be valid. So bit 5 - * must be zero, bit 6 must be set and bit 7 zero. - */ - c &= ~PNG_U32(32,32,0,32); - t = (c & ~0x1f1f1f1f) ^ 0x40404040; - - /* Subtract 65 for each 8 bit quantity, this must not overflow - * and each byte must then be in the range 0-25. - */ - c -= PNG_U32(65,65,65,65); - t |=c ; - - /* Subtract 26, handling the overflow which should set the top - * three bits of each byte. - */ - c -= PNG_U32(25,25,25,26); - t |= ~c; - - return (t & 0xe0e0e0e0) == 0; -} - -/**************************** CONTROL INFORMATION *****************************/ - -/* Information about a sequence of IDAT chunks, the chunks have been re-synced - * using sync_stream below and the new lengths are recorded here. Because the - * number of chunks is unlimited this is handled using a linked list of these - * structures. - */ -struct IDAT_list -{ - struct IDAT_list *next; /* Linked list */ - unsigned int length; /* Actual length of the array below */ - unsigned int count; /* Number of entries that are valid */ -# define IDAT_INIT_LENGTH 16 - png_uint_32 lengths[IDAT_INIT_LENGTH]; -}; - -static void -IDAT_list_init(struct IDAT_list *list) -{ - CLEAR(*list); - - list->next = NULL; - list->length = IDAT_INIT_LENGTH; -} - -static size_t -IDAT_list_size(struct IDAT_list *list, unsigned int length) - /* Return the size in bytes of an IDAT_list of the given length. */ -{ - if (list != NULL) - length = list->length; - - return sizeof *list - sizeof list->lengths + - length * sizeof list->lengths[0]; -} - -static void -IDAT_list_end(struct IDAT_list *IDAT_list) -{ - struct IDAT_list *list = IDAT_list->next; - - CLEAR(*IDAT_list); - - while (list != NULL) - { - struct IDAT_list *next = list->next; - - clear(list, IDAT_list_size(list, 0)); - free(list); - list = next; - } -} - -static struct IDAT_list * -IDAT_list_extend(struct IDAT_list *tail) -{ - /* Use the previous cached value if available. */ - struct IDAT_list *next = tail->next; - - if (next == NULL) - { - /* Insert a new, malloc'ed, block of IDAT information buffers, this - * one twice as large as the previous one: - */ - unsigned int length = 2 * tail->length; - - if (length < tail->length) /* arithmetic overflow */ - length = tail->length; - - next = png_voidcast(IDAT_list*, malloc(IDAT_list_size(NULL, length))); - CLEAR(*next); - - /* The caller must handle this: */ - if (next == NULL) - return NULL; - - next->next = NULL; - next->length = length; - tail->next = next; - } - - return next; -} - -/* GLOBAL CONTROL STRUCTURE */ -struct global -{ - /* PUBLIC GLOBAL VARIABLES: OWNER INITIALIZE */ - unsigned int errors :1; /* print file errors to stderr */ - unsigned int warnings :1; /* print libpng warnings to stderr */ - unsigned int optimize_zlib :1; /* Run optimization search */ - unsigned int quiet :2; /* don't output summaries */ - unsigned int verbose :3; /* various internal tracking */ - unsigned int skip :3; /* Non-critical chunks to skip */ -# define SKIP_NONE 0 -# define SKIP_BAD_CRC 1 /* Chunks with a bad CRC */ -# define SKIP_UNSAFE 2 /* Chunks not safe to copy */ -# define SKIP_UNUSED 3 /* Chunks not used by libpng */ -# define SKIP_TRANSFORM 4 /* Chunks only used in transforms */ -# define SKIP_COLOR 5 /* Everything but tRNS, sBIT, gAMA and sRGB */ -# define SKIP_ALL 6 /* Everything but tRNS and sBIT */ - - png_uint_32 idat_max; /* 0 to perform no re-chunking */ - - int status_code; /* Accumulated status code */ -# define TOO_FAR_BACK 0x01 /* found a too-far-back error */ -# define CRC_ERROR 0x02 /* fixed an invalid CRC */ -# define STREAM_ERROR 0x04 /* damaged PNG stream (may be fixable) */ -# define TRUNCATED 0x08 /* truncated but still readable */ -# define FILE_ERROR 0x10 /* could not read the file */ -# define WRITE_ERROR 0x20 /* write error (this terminates the read) */ -# define INTERNAL_ERROR 0x40 /* internal limits/errors encountered */ - - /* PUBLIC GLOBAL VARIABLES: USED INTERNALLY BY IDAT READ CODE */ - struct IDAT_list idat_cache; /* Cache of file IDAT information buffers */ - /* The structure is shared across all uses of this global control - * structure to avoid reallocation between IDAT streams. - */ -}; - -static int -global_end(struct global *global) -{ - - int rc; - - IDAT_list_end(&global->idat_cache); - rc = global->status_code; - CLEAR(*global); - return rc; -} - -static void -global_init(struct global *global) - /* Call this once (and only once) to initialize the control */ -{ - CLEAR(*global); - - /* Globals */ - global->errors = 0; - global->warnings = 0; - global->quiet = 0; - global->verbose = 0; - global->idat_max = 0; /* no re-chunking of IDAT */ - global->optimize_zlib = 0; - global->skip = SKIP_NONE; - global->status_code = 0; - - IDAT_list_init(&global->idat_cache); -} - -static int -skip_chunk_type(const struct global *global, png_uint_32 type) - /* Return true if this chunk is to be skipped according to the --strip - * option. This code needs to recognize all known ancillary chunks in order - * to handle the --strip=unsafe option. - */ -{ - /* Never strip critical chunks: */ - if (CRITICAL(type)) - return 0; - - switch (type) - { - /* Chunks that are treated as, effectively, critical because they affect - * correct interpretation of the pixel values: - */ - case png_tRNS: case png_sBIT: - return 0; - - /* Chunks that specify gamma encoding which should therefore only be - * removed the the user insists: - */ - case png_gAMA: case png_sRGB: - if (global->skip >= SKIP_ALL) - return 1; - return 0; - - /* Chunks that affect color interpretation - not used by libpng and rarely - * used by applications, but technically still required for correct - * interpretation of the image data: - */ - case png_cHRM: case png_iCCP: - if (global->skip >= SKIP_COLOR) - return 1; - return 0; - - /* Other chunks that are used by libpng in image transformations (as - * opposed to known chunks that have get/set APIs but are not otherwise - * used.) - */ - case png_bKGD: - if (global->skip >= SKIP_TRANSFORM) - return 1; - return 0; - - /* All other chunks that libpng knows about and affect neither image - * interpretation nor libpng transforms - chunks that are effectively - * unused by libpng even though libpng might recognize and store them. - */ - case png_fRAc: case png_gIFg: case png_gIFt: case png_gIFx: case png_hIST: - case png_iTXt: case png_oFFs: case png_pCAL: case png_pHYs: case png_sCAL: - case png_sPLT: case png_sTER: case png_tEXt: case png_tIME: case png_zTXt: - if (global->skip >= SKIP_UNUSED) - return 1; - return 0; - - /* Chunks that libpng does not know about (notice that this depends on the - * list above including all known chunks!) The decision here depends on - * whether the safe-to-copy bit is set in the chunk type. - */ - default: - if (SAFE_TO_COPY(type)) - { - if (global->skip >= SKIP_UNUSED) /* as above */ - return 1; - } - - else if (global->skip >= SKIP_UNSAFE) - return 1; - - return 0; - } -} - -/* PER-FILE CONTROL STRUCTURE */ -struct chunk; -struct IDAT; -struct file -{ - /* ANCESTORS */ - struct global *global; - - /* PUBLIC PER-FILE VARIABLES: CALLER INITIALIZE */ - const char * file_name; - const char * out_name; /* Name of output file (if required) */ - - /* PUBLIC PER-FILE VARIABLES: SET BY PNG READ CODE */ - /* File specific result codes */ - int status_code; /* Set to a bit mask of the following: */ - int read_errno; /* Records a read error errno */ - int write_errno; /* Records a write error errno */ - - /* IHDR information */ - png_uint_32 width; - png_uint_32 height; - png_byte bit_depth; - png_byte color_type; - png_byte compression_method; - png_byte filter_method; - png_byte interlace_method; - - udigit image_bytes[5]; - int image_digits; - - /* PROTECTED PER-FILE VARIABLES: USED BY THE READ CODE */ - FILE * file; /* Original PNG file */ - FILE * out; /* If a new one is being written */ - jmp_buf jmpbuf; /* Set while reading a PNG */ - - /* PROTECTED CHUNK SPECIFIC VARIABLES: USED BY CHUNK CODE */ - /* The following variables are used during reading to record the length, type - * and data position of the *next* chunk or, right at the start, the - * signature (in length,type). - * - * When a chunk control structure is instantiated these values are copied - * into the structure and can then be overritten with the data for the next - * chunk. - */ - fpos_t data_pos; /* Position of first byte of chunk data */ - png_uint_32 length; /* First word (length or signature start) */ - png_uint_32 type; /* Second word (type or signature end) */ - png_uint_32 crc; /* Running chunk CRC (used by read_chunk) */ - - /* These counts are maintained by the read and write routines below and are - * reset by the chunk handling code. They record the total number of bytes - * read or written for the chunk, including the header (length,type) bytes. - */ - png_uint_32 read_count; /* Count of bytes read (in the chunk) */ - png_uint_32 write_count; /* Count of bytes written (in the chunk) */ - int state; /* As defined here: */ -# define STATE_SIGNATURE 0 /* The signature is being written */ -# define STATE_CHUNKS 1 /* Non-IDAT chunks are being written */ -# define STATE_IDAT 2 /* An IDAT stream is being written */ - - /* Two pointers used to enable clean-up in the event of fatal errors and to - * hold state about the parser process (only one of each at present.) - */ - struct chunk * chunk; - struct IDAT * idat; - - /* Interface to allocate a new chunk or IDAT control structure. The result - * is returned by setting one or other of the above variables. Note that the - * relevant initializer is called by the allocator function. The alloc_ptr - * is used only by the implementation of the allocate function. - */ - void * alloc_ptr; - void (*alloc)(struct file*,int idat); - /* idat: allocate IDAT not chunk */ -}; - -/* Valid longjmp (stop) codes are: */ -#define LIBPNG_WARNING_CODE 1 /* generic png_error */ -#define LIBPNG_ERROR_CODE 2 /* generic png_error */ -#define ZLIB_ERROR_CODE 3 /* generic zlib error */ -#define INVALID_ERROR_CODE 4 /* detected an invalid PNG */ -#define READ_ERROR_CODE 5 /* read failed */ -#define WRITE_ERROR_CODE 6 /* error in write */ -#define UNEXPECTED_ERROR_CODE 7 /* unexpected (internal?) error */ - -static void -emit_string(const char *str, FILE *out) - /* Print a string with spaces replaced by '_' and non-printing characters by - * an octal escape. - */ -{ - for (; *str; ++str) - if (isgraph(UCHAR_MAX & *str)) - putc(*str, out); - - else if (isspace(UCHAR_MAX & *str)) - putc('_', out); - - else - fprintf(out, "\\%.3o", *str); -} - -static const char * -strcode(int code) -{ - switch (code) - { - case LIBPNG_WARNING_CODE: return "warning"; - case LIBPNG_ERROR_CODE: return "libpng"; - case ZLIB_ERROR_CODE: return "zlib"; - case INVALID_ERROR_CODE: return "invalid"; - case READ_ERROR_CODE: return "read"; - case WRITE_ERROR_CODE: return "write"; - case UNEXPECTED_ERROR_CODE: return "unexpected"; - default: return "INVALID"; - } -} - -static void -emit_error(struct file *file, int code, const char *what) - /* Generic error message routine, takes a 'stop' code but can be used - * elsewhere. Always outputs a message. - */ -{ - const char *reason; - int err = 0; - - switch (code) - { - case LIBPNG_WARNING_CODE: reason = "libpng warning:"; break; - case LIBPNG_ERROR_CODE: reason = "libpng error:"; break; - case ZLIB_ERROR_CODE: reason = "zlib error:"; break; - case INVALID_ERROR_CODE: reason = "invalid"; break; - case READ_ERROR_CODE: reason = "read failure:"; - err = file->read_errno; - break; - case WRITE_ERROR_CODE: reason = "write error"; - err = file->write_errno; - break; - case UNEXPECTED_ERROR_CODE: reason = "unexpected error:"; - err = file->read_errno; - if (err == 0) - err = file->write_errno; - break; - default: reason = "INVALID (internal error):"; break; - } - - if (err != 0) - fprintf(stderr, "%s: %s %s [%s]\n", file->file_name, reason, what, - strerror(err)); - - else - fprintf(stderr, "%s: %s %s\n", file->file_name, reason, what); -} - -static void chunk_end(struct chunk **); -static void IDAT_end(struct IDAT **); - -static int -file_end(struct file *file) -{ - int rc; - - /* If either of the chunk pointers are set end them here, the IDAT structure - * must be deallocated first as it may deallocate the chunk structure. - */ - if (file->idat != NULL) - IDAT_end(&file->idat); - - if (file->chunk != NULL) - chunk_end(&file->chunk); - - rc = file->status_code; - - if (file->file != NULL) - (void)fclose(file->file); - - if (file->out != NULL) - { - /* NOTE: this is bitwise |, all the following functions must execute and - * must succeed. - */ - if (ferror(file->out) | fflush(file->out) | fclose(file->out)) - { - perror(file->out_name); - emit_error(file, READ_ERROR_CODE, "output write error"); - rc |= WRITE_ERROR; - } - } - - /* Accumulate the result codes */ - file->global->status_code |= rc; - - CLEAR(*file); - - return rc; /* status code: non-zero on read or write error */ -} - -static int -file_init(struct file *file, struct global *global, const char *file_name, - const char *out_name, void *alloc_ptr, void (*alloc)(struct file*,int)) - /* Initialize a file control structure. This will open the given files as - * well. The status code returned is 0 on success, non zero (using the flags - * above) on a file open error. - */ -{ - CLEAR(*file); - file->global = global; - - file->file_name = file_name; - file->out_name = out_name; - file->status_code = 0; - file->read_errno = 0; - file->write_errno = 0; - - file->file = NULL; - file->out = NULL; - /* jmpbuf is garbage: must be set by read_png */ - - file->read_count = 0; - file->state = STATE_SIGNATURE; - - file->chunk = NULL; - file->idat = NULL; - - file->alloc_ptr = alloc_ptr; - file->alloc = alloc; - - /* Open the files: */ - assert(file_name != NULL); - file->file = fopen(file_name, "rb"); - - if (file->file == NULL) - { - file->read_errno = errno; - file->status_code |= FILE_ERROR; - /* Always output: please give a readable file! */ - perror(file_name); - return FILE_ERROR; - } - - if (out_name != NULL) - { - file->out = fopen(out_name, "wb"); - - if (file->out == NULL) - { - file->write_errno = errno; - file->status_code |= WRITE_ERROR; - perror(out_name); - return WRITE_ERROR; - } - } - - return 0; -} - -static void -log_error(struct file *file, int code, const char *what) - /* Like emit_error but checks the global 'errors' flag */ -{ - if (file->global->errors) - emit_error(file, code, what); -} - -static char -type_char(png_uint_32 v) -{ - /* In fact because chunk::chunk_type is validated prior to any call to this - * function it will always return a-zA-Z, but the extra codes are just there - * to help in finding internal (programming) errors. Note that the code only - * ever considers the low 7 bits of the value (so it is not necessary for the - * type_name function to mask of the byte.) - */ - if (v & 32) - return "!abcdefghijklmnopqrstuvwxyz56789"[(v-96)&31]; - - else - return "@ABCDEFGHIJKLMNOPQRSTUVWXYZ01234"[(v-64)&31]; -} - -static void -type_name(png_uint_32 type, FILE *out) -{ - putc(type_char(type >> 24), out); - putc(type_char(type >> 16), out); - putc(type_char(type >> 8), out); - putc(type_char(type ), out); -} - -static void -type_sep(FILE *out) -{ - putc(':', out); - putc(' ', out); -} - -static png_uint_32 current_type(struct file *file, int code); - -PNG_NORETURN static void -stop(struct file *file, int code, const char *what) - /* Return control when a PNG file cannot be read. This outputs an 'ERR' - * summary line too. - */ -{ - log_error(file, code, what); - - /* The chunk being read is typically identified by file->chunk or, if this is - * NULL, by file->type. This may be wrong if libpng reads ahead, but this - * only happens with IDAT where libpng reads the header then jumps around - * finding errors in the previous chunks. We know that is happening because - * we are at the start of the IDAT (i.e. no IDAT data has yet been written.) - * - * SUMMARY FORMAT (stop): - * - * IDAT ERR status code read-errno write-errno message file - * - * 'uncompressed' will be 0 if there was a problem in the IHDR. The errno - * values are emit_string(strerror(errno)). - */ - if (file->global->quiet < 2) /* need two quiets to stop this. */ - { - png_uint_32 type; - - if (file->chunk != NULL) - type = current_type(file, code); /* Gropes in struct chunk and IDAT */ - - else - type = file->type; - - if (type) - type_name(type, stdout); - - else /* magic: an IDAT header, produces bogons for too many IDATs */ - fputs("HEAD", stdout); /* not a registered chunk! */ - - printf(" ERR %.2x %s ", file->status_code, strcode(code)); - /* This only works one strerror at a time, because of the way strerror is - * implemented. - */ - emit_string(strerror(file->read_errno), stdout); - putc(' ', stdout); - emit_string(strerror(file->write_errno), stdout); - putc(' ', stdout); - emit_string(what, stdout); - putc(' ', stdout); - fputs(file->file_name, stdout); - putc('\n', stdout); - } - - file->status_code |= FILE_ERROR; - longjmp(file->jmpbuf, code); -} - -PNG_NORETURN static void -stop_invalid(struct file *file, const char *what) -{ - stop(file, INVALID_ERROR_CODE, what); -} - -static void -type_message(struct file *file, png_uint_32 type, const char *what) - /* Error message for a chunk; the chunk name comes from 'type' */ -{ - if (file->global->errors) - { - fputs(file->file_name, stderr); - type_sep(stderr); - type_name(type, stderr); - type_sep(stderr); - fputs(what, stderr); - putc('\n', stderr); - } -} - -/* Input file positioning - we jump around in the input file while reading - * stuff, these wrappers deal with the error handling. - */ -static void -file_getpos(struct file *file, fpos_t *pos) -{ - if (fgetpos(file->file, pos)) - { - /* This is unexpected, so perror it */ - perror(file->file_name); - stop(file, READ_ERROR_CODE, "fgetpos"); - } -} - -static void -file_setpos(struct file *file, const fpos_t *pos) -{ - if (fsetpos(file->file, pos)) - { - perror(file->file_name); - stop(file, READ_ERROR_CODE, "fsetpos"); - } -} - -static void -getpos(struct file *file) - /* Get the current position and store it in 'data_pos'. The corresponding - * setpos() function is chunk specific because it uses the copy of the - * position for the specific chunk. - */ -{ - file_getpos(file, &file->data_pos); -} - - -/* Read utility - read a single byte, returns a value in the range 0..255 or EOF - * on a read error. In the latter case status_code and read_errno are updated - * appropriately. - */ -static int -read_byte(struct file *file) -{ - int ch = getc(file->file); - - if (ch >= 0 && ch <= 255) - { - ++(file->read_count); - return ch; - } - - else if (ch != EOF) - { - file->status_code |= INTERNAL_ERROR; - file->read_errno = ERANGE; /* out of range character */ - - /* This is very unexpected; an error message is always output: */ - emit_error(file, UNEXPECTED_ERROR_CODE, "file read"); - } - -# ifdef EINTR - else if (errno == EINTR) /* Interrupted, try again */ - { - errno = 0; - return read_byte(file); - } -# endif - - else - { - /* An error, it doesn't really matter what the error is but it gets - * recorded anyway. - */ - if (ferror(file->file)) - file->read_errno = errno; - - else if (feof(file->file)) - file->read_errno = 0; /* I.e. a regular EOF, no error */ - - else /* unexpected */ - file->read_errno = EDOM; - } - - /* 'TRUNCATED' is used for all cases of failure to read a byte, because of - * the way libpng works a byte read is never attempted unless the byte is - * expected to be there, so EOF should not occur. - */ - file->status_code |= TRUNCATED; - return EOF; -} - -static png_byte -reread_byte(struct file *file) - /* Read a byte when an error is not expected to happen because the byte has - * been read before without error. - */ -{ - int ch = getc(file->file); - - if (errno != 0) - file->read_errno = errno; - - if (ch < 0 || ch > 255) - stop(file, UNEXPECTED_ERROR_CODE, "reread"); - - return (png_byte)ch; -} - -static png_uint_32 -reread_4(struct file *file) - /* The same but for a four byte quantity */ -{ - png_uint_32 result = 0; - int i = 0; - - while (++i <= 4) - result = (result << 8) + reread_byte(file); - - return result; -} - -static void -skip_12(struct file *file) - /* Skip exactly 12 bytes in the input stream - used to skip a CRC and chunk - * header that has been read before. - */ -{ - /* Since the chunks were read before this shouldn't fail: */ - if (fseek(file->file, 12, SEEK_CUR) != 0) - { - if (errno != 0) - file->read_errno = errno; - - stop(file, UNEXPECTED_ERROR_CODE, "reskip"); - } -} - -static void -write_byte(struct file *file, int b) - /* Write one byte to the output - this causes a fatal error if the write - * fails and the read of this PNG file immediately terminates. Just - * increments the write count if there is no output file. - */ -{ - if (file->out != NULL) - { - if (putc(b, file->out) != b) - { - file->write_errno = errno; - file->status_code |= WRITE_ERROR; - stop(file, WRITE_ERROR_CODE, "write byte"); - } - } - - ++(file->write_count); -} - -/* Derivatives of the read/write functions. */ -static unsigned int -read_4(struct file *file, png_uint_32 *pu) - /* Read four bytes, returns the number of bytes read successfully and, if all - * four bytes are read, assigns the result to *pu. - */ -{ - unsigned int i = 0; - png_uint_32 val = 0; - - do - { - int ch = read_byte(file); - - if (ch == EOF) - return i; - - val = (val << 8) + ch; - } while (++i < 4); - - *pu = val; - return i; -} - -/* CRC handling - read but calculate the CRC while doing so. */ -static int -crc_read_many(struct file *file, png_uint_32 length) - /* Reads 'length' bytes and updates the CRC, returns true on success, false - * if the input is truncated. - */ -{ - if (length > 0) - { - png_uint_32 crc = file->crc; - - do - { - int ch = read_byte(file); - - if (ch == EOF) - return 0; /* Truncated */ - - crc = crc_one_byte(crc, ch); - } - while (--length > 0); - - file->crc = crc; - } - - return 1; /* OK */ -} - -static int -calc_image_size(struct file *file) - /* Fill in the image_bytes field given the IHDR information, calls stop on - * error. - */ -{ - png_uint_16 pd = file->bit_depth; - - switch (file->color_type) - { - default: - stop_invalid(file, "IHDR: colour type"); - - invalid_bit_depth: - stop_invalid(file, "IHDR: bit depth"); - - case 0: /* g */ - if (pd != 1 && pd != 2 && pd != 4 && pd != 8 && pd != 16) - goto invalid_bit_depth; - break; - - case 3: - if (pd != 1 && pd != 2 && pd != 4 && pd != 8) - goto invalid_bit_depth; - break; - - case 2: /* rgb */ - if (pd != 8 && pd != 16) - goto invalid_bit_depth; - - pd = (png_uint_16)(pd * 3); - break; - - case 4: /* ga */ - if (pd != 8 && pd != 16) - goto invalid_bit_depth; - - pd = (png_uint_16)(pd * 2); - break; - - case 6: /* rgba */ - if (pd != 8 && pd != 16) - goto invalid_bit_depth; - - pd = (png_uint_16)(pd * 4); - break; - } - - if (file->width < 1 || file->width > 0x7fffffff) - stop_invalid(file, "IHDR: width"); - - else if (file->height < 1 || file->height > 0x7fffffff) - stop_invalid(file, "IHDR: height"); - - else if (file->compression_method != 0) - stop_invalid(file, "IHDR: compression method"); - - else if (file->filter_method != 0) - stop_invalid(file, "IHDR: filter method"); - - else switch (file->interlace_method) - { - case PNG_INTERLACE_ADAM7: - /* Interlacing makes the image larger because of the replication of - * both the filter byte and the padding to a byte boundary. - */ - { - int pass; - int image_digits = 0; - udigit row_width[2], row_bytes[3]; - - for (pass=0; pass<=6; ++pass) - { - png_uint_32 pw = PNG_PASS_COLS(file->width, pass); - - if (pw > 0) - { - int digits; - - /* calculate 1+((pw*pd+7)>>3) in row_bytes */ - digits = uarb_mult_digit(row_bytes, uarb_set(row_bytes, 7), - row_width, uarb_set(row_width, pw), pd); - digits = uarb_shift(row_bytes, digits, 3); - digits = uarb_inc(row_bytes, digits, 1); - - /* Add row_bytes * pass-height to the file image_bytes field - */ - image_digits = uarb_mult32(file->image_bytes, image_digits, - row_bytes, digits, - PNG_PASS_ROWS(file->height, pass)); - } - } - - file->image_digits = image_digits; - } - break; - - case PNG_INTERLACE_NONE: - { - int digits; - udigit row_width[2], row_bytes[3]; - - /* As above, but use image_width in place of the pass width: */ - digits = uarb_mult_digit(row_bytes, uarb_set(row_bytes, 7), - row_width, uarb_set(row_width, file->width), pd); - digits = uarb_shift(row_bytes, digits, 3); - digits = uarb_inc(row_bytes, digits, 1); - - /* Set row_bytes * image-height to the file image_bytes field */ - file->image_digits = uarb_mult32(file->image_bytes, 0, - row_bytes, digits, file->height); - } - break; - - default: - stop_invalid(file, "IHDR: interlace method"); - } - - assert(file->image_digits >= 1 && file->image_digits <= 5); - return 1; -} - -/* PER-CHUNK CONTROL STRUCTURE - * This structure is instantiated for each chunk, except for the IDAT chunks - * where one chunk control structure is used for the whole of a single stream of - * IDAT chunks (see the IDAT control structure below). - */ -struct chunk -{ - /* ANCESTORS */ - struct file * file; - struct global * global; - - /* PUBLIC IDAT INFORMATION: SET BY THE ZLIB CODE */ - udigit uncompressed_bytes[5]; - int uncompressed_digits; - udigit compressed_bytes[5]; - int compressed_digits; - - /* PUBLIC PER-CHUNK INFORMATION: USED BY CHUNK READ CODE */ - /* This information is filled in by chunk_init from the data in the file - * control structure, but chunk_length may be changed later. - */ - fpos_t chunk_data_pos; /* Position of first byte of chunk data */ - png_uint_32 chunk_length; /* From header (or modified below) */ - png_uint_32 chunk_type; /* From header */ - - /* PUBLIC PER-CHUNK INFORMATION: FOR THE CHUNK WRITE CODE */ - png_uint_32 write_crc; /* Output CRC (may differ from read_crc) */ - png_uint_32 rewrite_offset; /* Count of bytes before rewrite. */ - int rewrite_length; /* Number of bytes left to change */ - png_byte rewrite_buffer[2]; /* Buffer of new byte values */ -}; - -static void -chunk_message(struct chunk *chunk, const char *message) -{ - type_message(chunk->file, chunk->chunk_type, message); -} - -static void -chunk_end(struct chunk **chunk_var) -{ - struct chunk *chunk = *chunk_var; - - *chunk_var = NULL; - CLEAR(*chunk); -} - -static void -chunk_init(struct chunk * const chunk, struct file * const file) - /* When a chunk is initialized the file length/type/pos are copied into the - * corresponding chunk fields and the new chunk is registered in the file - * structure. There can only be one chunk at a time. - * - * NOTE: this routine must onely be called from the file alloc routine! - */ -{ - assert(file->chunk == NULL); - - CLEAR(*chunk); - - chunk->file = file; - chunk->global = file->global; - - chunk->chunk_data_pos = file->data_pos; - chunk->chunk_length = file->length; - chunk->chunk_type = file->type; - - /* Compresssed/uncompressed size information (from the zlib control structure - * that is used to check the compressed data in a chunk.) - */ - chunk->uncompressed_digits = 0; - chunk->compressed_digits = 0; - - file->chunk = chunk; -} - -static png_uint_32 -current_type(struct file *file, int code) - /* Guess the actual chunk type that causes a stop() */ -{ - /* This may return png_IDAT for errors detected (late) in the header; that - * includes any inter-chunk consistency check that libpng performs. Assume - * that if the chunk_type is png_IDAT and the file write count is 8 this is - * what is happening. - */ - if (file->chunk != NULL) - { - png_uint_32 type = file->chunk->chunk_type; - - /* This is probably wrong for the excess IDATs case, because then libpng - * whines about too many of them (apparently in some cases erroneously) - * when the header is read. - */ - if (code <= LIBPNG_ERROR_CODE && type == png_IDAT && - file->write_count == 8) - type = 0; /* magic */ - - return type; - } - - else - return file->type; -} - -static void -setpos(struct chunk *chunk) - /* Reset the position to 'chunk_data_pos' - the start of the data for this - * chunk. As a side effect the read_count in the file is reset to 8, just - * after the length/type header. - */ -{ - chunk->file->read_count = 8; - file_setpos(chunk->file, &chunk->chunk_data_pos); -} - -/* Specific chunk handling - called for each chunk header, all special chunk - * processing is initiated in these functions. - */ -/* The next functions handle special processing for those chunks with LZ data, - * the data is identified and checked for validity. If there are problems which - * cannot be corrected the routines return false, otherwise true (although - * modification to the zlib header may be required.) - * - * The compressed data is in zlib format (RFC1950) and consequently has a - * minimum length of 7 bytes. - */ -static int zlib_check(struct file *file, png_uint_32 offset); - -static int -process_zTXt_iCCP(struct file *file) - /* zTXt and iCCP have exactly the same form - keyword, null, compression - * method then compressed data. - */ -{ - struct chunk *chunk = file->chunk; - png_uint_32 length; - png_uint_32 index = 0; - - assert(chunk != NULL && file->idat == NULL); - length = chunk->chunk_length; - setpos(chunk); - - while (length >= 9) - { - --length; - ++index; - if (reread_byte(file) == 0) /* keyword null terminator */ - { - --length; - ++index; - (void)reread_byte(file); /* compression method */ - return zlib_check(file, index); - } - } - - chunk_message(chunk, "too short"); - return 0; /* skip */ -} - -static int -process_iTXt(struct file *file) -{ - /* Like zTXt but more fields. */ - struct chunk *chunk = file->chunk; - png_uint_32 length; - png_uint_32 index = 0; - - assert(chunk != NULL && file->idat == NULL); - length = chunk->chunk_length; - setpos(chunk); - - while (length >= 5) - { - --length; - ++index; - if (reread_byte(file) == 0) /* keyword null terminator */ - { - --length; - ++index; - if (reread_byte(file) == 0) /* uncompressed text */ - return 1; /* nothing to check */ - - --length; - ++index; - (void)reread_byte(file); /* compression method */ - - /* Skip the language tag (null terminated). */ - while (length >= 9) - { - --length; - ++index; - if (reread_byte(file) == 0) /* terminator */ - { - /* Skip the translated keyword */ - while (length >= 8) - { - --length; - ++index; - if (reread_byte(file) == 0) /* terminator */ - return zlib_check(file, index); - } - } - } - - /* Ran out of bytes in the compressed case. */ - break; - } - } - - log_error(file, INVALID_ERROR_CODE, "iTXt chunk length"); - - return 0; /* skip */ -} - -/* IDAT READ/WRITE CONTROL STRUCTURE */ -struct IDAT -{ - /* ANCESTORS */ - struct file * file; - struct global * global; - - /* PROTECTED IDAT INFORMATION: SET BY THE IDAT READ CODE */ - struct IDAT_list *idat_list_head; /* START of the list of IDAT information */ - struct IDAT_list *idat_list_tail; /* *END* of the list of IDAT information */ - - /* PROTECTED IDAT INFORMATION: USED BY THE IDAT WRITE CODE */ - struct IDAT_list *idat_cur; /* Current list entry */ - unsigned int idat_count; /* And the *current* index into the list */ - png_uint_32 idat_index; /* Index of *next* input byte to write */ - png_uint_32 idat_length; /* Cache of current chunk length */ -}; - -/* NOTE: there is currently no IDAT_reset, so a stream cannot contain more than - * one IDAT sequence (i.e. MNG is not supported). - */ - -static void -IDAT_end(struct IDAT **idat_var) -{ - struct IDAT *idat = *idat_var; - struct file *file = idat->file; - - *idat_var = NULL; - - CLEAR(*idat); - - assert(file->chunk != NULL); - chunk_end(&file->chunk); - - /* Regardless of why the IDAT was killed set the state back to CHUNKS (it may - * already be CHUNKS because the state isn't changed until process_IDAT - * returns; a stop will cause IDAT_end to be entered in state CHUNKS!) - */ - file->state = STATE_CHUNKS; -} - -static void -IDAT_init(struct IDAT * const idat, struct file * const file) - /* When the chunk is png_IDAT instantiate an IDAT control structure in place - * of a chunk control structure. The IDAT will instantiate a chunk control - * structure using the file alloc routine. - * - * NOTE: this routine must only be called from the file alloc routine! - */ -{ - assert(file->chunk == NULL); - assert(file->idat == NULL); - - CLEAR(*idat); - - idat->file = file; - idat->global = file->global; - - /* Initialize the tail to the pre-allocated buffer and set the count to 0 - * (empty.) - */ - idat->global->idat_cache.count = 0; - idat->idat_list_head = idat->idat_list_tail = &idat->global->idat_cache; - - /* Now the chunk. The allocator calls the initializer of the new chunk and - * stores the result in file->chunk: - */ - file->alloc(file, 0/*chunk*/); - assert(file->chunk != NULL); - - /* And store this for cleanup (and to check for double alloc or failure to - * free.) - */ - file->idat = idat; -} - -static png_uint_32 -rechunk_length(struct IDAT *idat) - /* Return the length for the next IDAT chunk, taking into account - * rechunking. - */ -{ - png_uint_32 len = idat->global->idat_max; - - if (len == 0) /* use original chunk lengths */ - { - const struct IDAT_list *cur; - unsigned int count; - - if (idat->idat_index == 0) /* at the new chunk (first time) */ - return idat->idat_length; /* use the cache */ - - /* Otherwise rechunk_length is called at the end of a chunk for the length - * of the next one. - */ - cur = idat->idat_cur; - count = idat->idat_count; - - assert(idat->idat_index == idat->idat_length && - idat->idat_length == cur->lengths[count]); - - /* Return length of the *next* chunk */ - if (++count < cur->count) - return cur->lengths[count]; - - /* End of this list */ - assert(cur != idat->idat_list_tail); - cur = cur->next; - assert(cur != NULL && cur->count > 0); - return cur->lengths[0]; - } - - else /* rechunking */ - { - /* The chunk size is the lesser of file->idat_max and the number - * of remaining bytes. - */ - png_uint_32 have = idat->idat_length - idat->idat_index; - - if (len > have) - { - struct IDAT_list *cur = idat->idat_cur; - unsigned int j = idat->idat_count+1; /* the next IDAT in the list */ - - do - { - /* Add up the remaining bytes. This can't overflow because the - * individual lengths are always <= 0x7fffffff, so when we add two - * of them overflow is not possible. - */ - assert(cur != NULL); - - for (;;) - { - /* NOTE: IDAT_list::count here, not IDAT_list::length */ - for (; j < cur->count; ++j) - { - have += cur->lengths[j]; - if (len <= have) - return len; - } - - /* If this was the end return the count of the available bytes */ - if (cur == idat->idat_list_tail) - return have; - - cur = cur->next; - j = 0; - } - } - while (len > have); - } - - return len; - } -} - -static int -process_IDAT(struct file *file) - /* Process the IDAT stream, this is the more complex than the preceding - * cases because the compressed data is spread across multiple IDAT chunks - * (typically). Rechunking of the data is not handled here; all this - * function does is establish whether the zlib header needs to be modified. - * - * Initially the function returns false, indicating that the chunk should not - * be written. It does this until the last IDAT chunk is passed in, then it - * checks the zlib data and returns true. - * - * It does not return false on a fatal error; it calls stop instead. - * - * The caller must have an instantiated (IDAT) control structure and it must - * have extent over the whole read of the IDAT stream. For a PNG this means - * the whole PNG read, for MNG it could have lesser extent. - */ -{ - struct IDAT_list *list; - - assert(file->idat != NULL && file->chunk != NULL); - - /* We need to first check the entire sequence of IDAT chunks to ensure the - * stream is in sync. Do this by building a list of all the chunks and - * recording the length of each because the length may have been fixed up by - * sync_stream below. - * - * At the end of the list of chunks, where the type of the next chunk is not - * png_IDAT, process the whole stream using the list data to check validity - * then return control to the start and rewrite everything. - */ - list = file->idat->idat_list_tail; - - if (list->count == list->length) - { - list = IDAT_list_extend(list); - - if (list == NULL) - stop(file, READ_ERROR_CODE, "out of memory"); - - /* Move to the next block */ - list->count = 0; - file->idat->idat_list_tail = list; - } - - /* And fill in the next IDAT information buffer. */ - list->lengths[(list->count)++] = file->chunk->chunk_length; - - /* The type of the next chunk was recorded in the file control structure by - * the caller, if this is png_IDAT return 'skip' to the caller. - */ - if (file->type == png_IDAT) - return 0; /* skip this for the moment */ - - /* This is the final IDAT chunk, so run the tests to check for the too far - * back error and possibly optimize the window bits. This means going back - * to the start of the first chunk data, which is stored in the original - * chunk allocation. - */ - setpos(file->chunk); - - if (zlib_check(file, 0)) - { - struct IDAT *idat; - int cmp; - - /* The IDAT stream was successfully uncompressed; see whether it - * contained the correct number of bytes of image data. - */ - cmp = uarb_cmp(file->image_bytes, file->image_digits, - file->chunk->uncompressed_bytes, file->chunk->uncompressed_digits); - - if (cmp < 0) - type_message(file, png_IDAT, "extra uncompressed data"); - - else if (cmp > 0) - stop(file, LIBPNG_ERROR_CODE, "IDAT: uncompressed data too small"); - - /* Return the stream to the start of the first IDAT chunk; the length - * is set in the write case below but the input chunk variables must be - * set (once) here: - */ - setpos(file->chunk); - - idat = file->idat; - idat->idat_cur = idat->idat_list_head; - idat->idat_length = idat->idat_cur->lengths[0]; - idat->idat_count = 0; /* Count of chunks read in current list */ - idat->idat_index = 0; /* Index into chunk data */ - - /* Update the chunk length to the correct value for the IDAT chunk: */ - file->chunk->chunk_length = rechunk_length(idat); - - /* Change the state to writing IDAT chunks */ - file->state = STATE_IDAT; - - return 1; - } - - else /* Failure to decompress the IDAT stream; give up. */ - stop(file, ZLIB_ERROR_CODE, "could not uncompress IDAT"); -} - -/* ZLIB CONTROL STRUCTURE */ -struct zlib -{ - /* ANCESTORS */ - struct IDAT * idat; /* NOTE: May be NULL */ - struct chunk * chunk; - struct file * file; - struct global *global; - - /* GLOBAL ZLIB INFORMATION: SET BY THE CALLER */ - png_uint_32 rewrite_offset; - - /* GLOBAL ZLIB INFORMATION: SET BY THE ZLIB READ CODE */ - udigit compressed_bytes[5]; - int compressed_digits; - udigit uncompressed_bytes[5]; - int uncompressed_digits; - int file_bits; /* window bits from the file */ - int ok_bits; /* Set <16 on a successful read */ - int cksum; /* Set on a checksum error */ - - /* PROTECTED ZLIB INFORMATION: USED BY THE ZLIB ROUTINES */ - z_stream z; - png_uint_32 extra_bytes; /* Count of extra compressed bytes */ - int state; - int rc; /* Last return code */ - int window_bits; /* 0 if no change */ - png_byte header[2]; -}; - -static const char * -zlib_flevel(struct zlib *zlib) -{ - switch (zlib->header[1] >> 6) - { - case 0: return "supfast"; - case 1: return "stdfast"; - case 2: return "default"; - case 3: return "maximum"; - default: assert(UNREACHED); - } - - return "COMPILER BUG"; -} - -static const char * -zlib_rc(struct zlib *zlib) - /* Return a string for the zlib return code */ -{ - switch (zlib->rc) - { - case Z_OK: return "Z_OK"; - case Z_STREAM_END: return "Z_STREAM_END"; - case Z_NEED_DICT: return "Z_NEED_DICT"; - case Z_ERRNO: return "Z_ERRNO"; - case Z_STREAM_ERROR: return "Z_STREAM_ERROR"; - case Z_DATA_ERROR: return "Z_DATA_ERROR"; - case Z_MEM_ERROR: return "Z_MEM_ERROR"; - case Z_BUF_ERROR: return "Z_BUF_ERROR"; - case Z_VERSION_ERROR: return "Z_VERSION_ERROR"; - default: return "Z_*INVALID_RC*"; - } -} - -static void -zlib_message(struct zlib *zlib, int unexpected) - /* Output a message given a zlib rc */ -{ - if (zlib->global->errors) - { - const char *reason = zlib->z.msg; - - if (reason == NULL) - reason = "[no message]"; - - fputs(zlib->file->file_name, stderr); - type_sep(stderr); - type_name(zlib->chunk->chunk_type, stderr); - fprintf(stderr, ": %szlib error: %d (%s) (%s)\n", - unexpected ? "unexpected " : "", zlib->rc, zlib_rc(zlib), reason); - } -} - -static void -zlib_end(struct zlib *zlib) -{ - /* Output the summary line now; this ensures a summary line always gets - * output regardless of the manner of exit. - */ - if (!zlib->global->quiet) - { - if (zlib->ok_bits < 16) /* stream was read ok */ - { - const char *reason; - - if (zlib->cksum) - reason = "CHK"; /* checksum error */ - - else if (zlib->ok_bits > zlib->file_bits) - reason = "TFB"; /* fixing a too-far-back error */ - - else if (zlib->ok_bits == zlib->file_bits) - reason = "OK "; - - else - reason = "OPT"; /* optimizing window bits */ - - /* SUMMARY FORMAT (for a successful zlib inflate): - * - * IDAT reason flevel file-bits ok-bits compressed uncompressed file - */ - type_name(zlib->chunk->chunk_type, stdout); - printf(" %s %s %d %d ", reason, zlib_flevel(zlib), zlib->file_bits, - zlib->ok_bits); - uarb_print(zlib->compressed_bytes, zlib->compressed_digits, stdout); - putc(' ', stdout); - uarb_print(zlib->uncompressed_bytes, zlib->uncompressed_digits, - stdout); - putc(' ', stdout); - fputs(zlib->file->file_name, stdout); - putc('\n', stdout); - } - - else - { - /* This is a zlib read error; the chunk will be skipped. For an IDAT - * stream this will also cause a fatal read error (via stop()). - * - * SUMMARY FORMAT: - * - * IDAT SKP flevel file-bits z-rc compressed message file - * - * z-rc is the zlib failure code; message is the error message with - * spaces replaced by '-'. The compressed byte count indicates where - * in the zlib stream the error occured. - */ - type_name(zlib->chunk->chunk_type, stdout); - printf(" SKP %s %d %s ", zlib_flevel(zlib), zlib->file_bits, - zlib_rc(zlib)); - uarb_print(zlib->compressed_bytes, zlib->compressed_digits, stdout); - putc(' ', stdout); - emit_string(zlib->z.msg ? zlib->z.msg : "[no_message]", stdout); - putc(' ', stdout); - fputs(zlib->file->file_name, stdout); - putc('\n', stdout); - } - } - - if (zlib->state >= 0) - { - zlib->rc = inflateEnd(&zlib->z); - - if (zlib->rc != Z_OK) - zlib_message(zlib, 1/*unexpected*/); - } - - CLEAR(*zlib); -} - -static int -zlib_reset(struct zlib *zlib, int window_bits) - /* Reinitializes a zlib with a different window_bits */ -{ - assert(zlib->state >= 0); /* initialized by zlib_init */ - - zlib->z.next_in = Z_NULL; - zlib->z.avail_in = 0; - zlib->z.next_out = Z_NULL; - zlib->z.avail_out = 0; - - zlib->window_bits = window_bits; - zlib->compressed_digits = 0; - zlib->uncompressed_digits = 0; - - zlib->state = 0; /* initialized, once */ - zlib->rc = inflateReset2(&zlib->z, 0); - if (zlib->rc != Z_OK) - { - zlib_message(zlib, 1/*unexpected*/); - return 0; - } - - return 1; -} - -static int -zlib_init(struct zlib *zlib, struct IDAT *idat, struct chunk *chunk, - int window_bits, png_uint_32 offset) - /* Initialize a zlib_control; the result is true/false */ -{ - CLEAR(*zlib); - - zlib->idat = idat; - zlib->chunk = chunk; - zlib->file = chunk->file; - zlib->global = chunk->global; - zlib->rewrite_offset = offset; /* never changed for this zlib */ - - /* *_out does not need to be set: */ - zlib->z.next_in = Z_NULL; - zlib->z.avail_in = 0; - zlib->z.zalloc = Z_NULL; - zlib->z.zfree = Z_NULL; - zlib->z.opaque = Z_NULL; - - zlib->state = -1; - zlib->window_bits = window_bits; - - zlib->compressed_digits = 0; - zlib->uncompressed_digits = 0; - - /* These values are sticky across reset (in addition to the stuff in the - * first block, which is actually constant.) - */ - zlib->file_bits = 16; - zlib->ok_bits = 16; /* unset */ - zlib->cksum = 0; /* set when a checksum error is detected */ - - /* '0' means use the header; inflateInit2 should always succeed because it - * does nothing apart from allocating the internal zstate. - */ - zlib->rc = inflateInit2(&zlib->z, 0); - if (zlib->rc != Z_OK) - { - zlib_message(zlib, 1/*unexpected*/); - return 0; - } - - else - { - zlib->state = 0; /* initialized */ - return 1; - } -} - -static int -max_window_bits(uarbc size, int ndigits) - /* Return the zlib stream window bits required for data of the given size. */ -{ - png_uint_16 cb; - - if (ndigits > 1) - return 15; - - cb = size[0]; - - if (cb > 16384) return 15; - if (cb > 8192) return 14; - if (cb > 4096) return 13; - if (cb > 2048) return 12; - if (cb > 1024) return 11; - if (cb > 512) return 10; - if (cb > 256) return 9; - return 8; -} - -static int -zlib_advance(struct zlib *zlib, png_uint_32 nbytes) - /* Read nbytes compressed bytes; the stream will be initialized if required. - * Bytes are always being reread and errors are fatal. The return code is as - * follows: - * - * -1: saw the "too far back" error - * 0: ok, keep going - * 1: saw Z_STREAM_END (zlib->extra_bytes indicates too much data) - * 2: a zlib error that cannot be corrected (error message already - * output if required.) - */ -# define ZLIB_TOO_FAR_BACK (-1) -# define ZLIB_OK 0 -# define ZLIB_STREAM_END 1 -# define ZLIB_FATAL 2 -{ - int state = zlib->state; - int endrc = ZLIB_OK; - png_uint_32 in_bytes = 0; - struct file *file = zlib->file; - - assert(state >= 0); - - while (in_bytes < nbytes && endrc == ZLIB_OK) - { - png_uint_32 out_bytes; - int flush; - png_byte bIn = reread_byte(file); - png_byte bOut; - - switch (state) - { - case 0: /* first header byte */ - { - int file_bits = 8+(bIn >> 4); - int new_bits = zlib->window_bits; - - zlib->file_bits = file_bits; - - /* Check against the existing value - it may not need to be - * changed. - */ - if (new_bits == 0) /* no change */ - zlib->window_bits = file_bits; - - else if (new_bits != file_bits) /* rewrite required */ - bIn = (png_byte)((bIn & 0xf) + ((new_bits-8) << 4)); - } - - zlib->header[0] = bIn; - zlib->state = state = 1; - break; - - case 1: /* second header byte */ - { - int b2 = bIn & 0xe0; /* top 3 bits */ - - /* The checksum calculation, on the first 11 bits: */ - b2 += 0x1f - ((zlib->header[0] << 8) + b2) % 0x1f; - - /* Update the checksum byte if required: */ - if (bIn != b2) - { - /* If the first byte wasn't changed this indicates an error in - * the checksum calculation; signal this by setting file_bits - * (not window_bits) to 0. - */ - if (zlib->file_bits == zlib->window_bits) - zlib->cksum = 1; - - bIn = (png_byte)b2; - } - } - - zlib->header[1] = bIn; - zlib->state = state = 2; - break; - - default: /* After the header bytes */ - break; - } - - /* For some streams, perhaps only those compressed with 'superfast - * compression' (which results in a lot of copying) Z_BUF_ERROR can happen - * immediately after all output has been flushed on the next input byte. - * This is handled below when Z_BUF_ERROR is detected by adding an output - * byte. - */ - zlib->z.next_in = &bIn; - zlib->z.avail_in = 1; - zlib->z.next_out = &bOut; - zlib->z.avail_out = 0; /* Initially */ - - /* Initially use Z_NO_FLUSH in an attempt to persuade zlib to look at this - * byte without confusing what is going on with output. - */ - flush = Z_NO_FLUSH; - out_bytes = 0; - - /* NOTE: expression 3 is only evaluted on 'continue', because of the - * 'break' at the end of this loop below. - */ - for (;endrc == ZLIB_OK; - flush = Z_SYNC_FLUSH, - zlib->z.next_out = &bOut, - zlib->z.avail_out = 1, - ++out_bytes) - { - zlib->rc = inflate(&zlib->z, flush); - out_bytes -= zlib->z.avail_out; - - switch (zlib->rc) - { - case Z_BUF_ERROR: - if (zlib->z.avail_out == 0) - continue; /* Try another output byte. */ - - if (zlib->z.avail_in == 0) - break; /* Try another input byte */ - - /* Both avail_out and avail_in are 1 yet zlib returned a code - * indicating no progress was possible. This is unexpected. - */ - zlib_message(zlib, 1/*unexpected*/); - endrc = ZLIB_FATAL; /* stop processing */ - break; - - case Z_OK: - /* Zlib is supposed to have made progress: */ - assert(zlib->z.avail_out == 0 || zlib->z.avail_in == 0); - continue; - - case Z_STREAM_END: - /* This is the successful end. */ - zlib->state = 3; /* end of stream */ - endrc = ZLIB_STREAM_END; - break; - - case Z_NEED_DICT: - zlib_message(zlib, 0/*stream error*/); - endrc = ZLIB_FATAL; - break; - - case Z_DATA_ERROR: - /* The too far back error can be corrected, others cannot: */ - if (zlib->z.msg != NULL && - strcmp(zlib->z.msg, "invalid distance too far back") == 0) - { - endrc = ZLIB_TOO_FAR_BACK; - break; - } - /* FALL THROUGH */ - - default: - zlib_message(zlib, 0/*stream error*/); - endrc = ZLIB_FATAL; - break; - } /* switch (inflate rc) */ - - /* Control gets here when further output is not possible; endrc may - * still be ZLIB_OK if more input is required. - */ - break; - } /* for (output bytes) */ - - /* Keep a running count of output byte produced: */ - zlib->uncompressed_digits = uarb_add32(zlib->uncompressed_bytes, - zlib->uncompressed_digits, out_bytes); - - /* Keep going, the loop will terminate when endrc is no longer set to - * ZLIB_OK or all the input bytes have been consumed; meanwhile keep - * adding input bytes. - */ - assert(zlib->z.avail_in == 0 || endrc != ZLIB_OK); - - in_bytes += 1 - zlib->z.avail_in; - } /* while (input bytes) */ - - assert(in_bytes == nbytes || endrc != ZLIB_OK); - - /* Update the running total of input bytes consumed */ - zlib->compressed_digits = uarb_add32(zlib->compressed_bytes, - zlib->compressed_digits, in_bytes - zlib->z.avail_in); - - /* At the end of the stream update the chunk with the accumulated - * information if it is an improvement: - */ - if (endrc == ZLIB_STREAM_END && zlib->window_bits < zlib->ok_bits) - { - struct chunk *chunk = zlib->chunk; - - chunk->uncompressed_digits = uarb_copy(chunk->uncompressed_bytes, - zlib->uncompressed_bytes, zlib->uncompressed_digits); - chunk->compressed_digits = uarb_copy(chunk->compressed_bytes, - zlib->compressed_bytes, zlib->compressed_digits); - chunk->rewrite_buffer[0] = zlib->header[0]; - chunk->rewrite_buffer[1] = zlib->header[1]; - - if (zlib->window_bits != zlib->file_bits || zlib->cksum) - { - /* A rewrite is required */ - chunk->rewrite_offset = zlib->rewrite_offset; - chunk->rewrite_length = 2; - } - - else - { - chunk->rewrite_offset = 0; - chunk->rewrite_length = 0; - } - - if (in_bytes < nbytes) - chunk_message(chunk, "extra compressed data"); - - zlib->extra_bytes = nbytes - in_bytes; - zlib->ok_bits = zlib->window_bits; - } - - return endrc; -} - -static int -zlib_run(struct zlib *zlib) - /* Like zlib_advance but also handles a stream of IDAT chunks. */ -{ - /* The 'extra_bytes' field is set by zlib_advance if there is extra - * compressed data in the chunk it handles (if it sees Z_STREAM_END before - * all the input data has been used.) This function uses the value to update - * the correct chunk length, so the problem should only ever be detected once - * for each chunk. zlib_advance outputs the error message, though see the - * IDAT specific check below. - */ - zlib->extra_bytes = 0; - - if (zlib->idat != NULL) - { - struct IDAT_list *list = zlib->idat->idat_list_head; - struct IDAT_list *last = zlib->idat->idat_list_tail; - int skip = 0; - - /* 'rewrite_offset' is the offset of the LZ data within the chunk, for - * IDAT it should be 0: - */ - assert(zlib->rewrite_offset == 0); - - /* Process each IDAT_list in turn; the caller has left the stream - * positioned at the start of the first IDAT chunk data. - */ - for (;;) - { - const unsigned int count = list->count; - unsigned int i; - - for (i = 0; i<count; ++i) - { - int rc; - - if (skip > 0) /* Skip CRC and next IDAT header */ - skip_12(zlib->file); - - skip = 12; /* for the next time */ - - rc = zlib_advance(zlib, list->lengths[i]); - - switch (rc) - { - case ZLIB_OK: /* keep going */ - break; - - case ZLIB_STREAM_END: /* stop */ - /* There may be extra chunks; if there are and one of them is - * not zero length output the 'extra data' message. Only do - * this check if errors are being output. - */ - if (zlib->global->errors && zlib->extra_bytes == 0) - { - struct IDAT_list *check = list; - int j = i+1, jcount = count; - - for (;;) - { - for (; j<jcount; ++j) - if (check->lengths[j] > 0) - { - chunk_message(zlib->chunk, - "extra compressed data"); - goto end_check; - } - - if (check == last) - break; - - check = check->next; - jcount = check->count; - j = 0; - } - } - - end_check: - /* Terminate the list at the current position, reducing the - * length of the last IDAT too if required. - */ - list->lengths[i] -= zlib->extra_bytes; - list->count = i+1; - zlib->idat->idat_list_tail = list; - /* FALL THROUGH */ - - default: - return rc; - } - } - - /* At the end of the compressed data and Z_STREAM_END was not seen. */ - if (list == last) - return ZLIB_OK; - - list = list->next; - } - } - - else - { - struct chunk *chunk = zlib->chunk; - int rc; - - assert(zlib->rewrite_offset < chunk->chunk_length); - - rc = zlib_advance(zlib, chunk->chunk_length - zlib->rewrite_offset); - - /* The extra bytes in the chunk are handled now by adjusting the chunk - * length to exclude them; the zlib data is always stored at the end of - * the PNG chunk (although clearly this is not necessary.) zlib_advance - * has already output a warning message. - */ - chunk->chunk_length -= zlib->extra_bytes; - return rc; - } -} - -static int /* global function; not a member function */ -zlib_check(struct file *file, png_uint_32 offset) - /* Check the stream of zlib compressed data in either idat (if given) or (if - * not) chunk. In fact it is zlib_run that handles the difference in reading - * a single chunk and a list of IDAT chunks. - * - * In either case the input file must be positioned at the first byte of zlib - * compressed data (the first header byte). - * - * The return value is true on success, including the case where the zlib - * header may need to be rewritten, and false on an unrecoverable error. - * - * In the case of IDAT chunks 'offset' should be 0. - */ -{ - fpos_t start_pos; - struct zlib zlib; - - /* Record the start of the LZ data to allow a re-read. */ - file_getpos(file, &start_pos); - - /* First test the existing (file) window bits: */ - if (zlib_init(&zlib, file->idat, file->chunk, 0/*window bits*/, offset)) - { - int min_bits, max_bits, rc; - - /* The first run using the existing window bits. */ - rc = zlib_run(&zlib); - - switch (rc) - { - case ZLIB_TOO_FAR_BACK: - /* too far back error */ - file->status_code |= TOO_FAR_BACK; - min_bits = zlib.window_bits + 1; - max_bits = 15; - break; - - case ZLIB_STREAM_END: - if (!zlib.global->optimize_zlib && - zlib.window_bits == zlib.file_bits && !zlib.cksum) - { - /* The trivial case where the stream is ok and optimization was - * not requested. - */ - zlib_end(&zlib); - return 1; - } - - max_bits = max_window_bits(zlib.uncompressed_bytes, - zlib.uncompressed_digits); - if (zlib.ok_bits < max_bits) - max_bits = zlib.ok_bits; - min_bits = 8; - - /* cksum is set if there is an error in the zlib header checksum - * calculation in the original file (and this may be the only reason - * a rewrite is required). We can't rely on the file window bits in - * this case, so do the optimization anyway. - */ - if (zlib.cksum) - chunk_message(zlib.chunk, "zlib checkum"); - break; - - - case ZLIB_OK: - /* Truncated stream; unrecoverable, gets converted to ZLIB_FATAL */ - zlib.z.msg = PNGZ_MSG_CAST("[truncated]"); - zlib_message(&zlib, 0/*expected*/); - /* FALL THROUGH */ - - default: - /* Unrecoverable error; skip the chunk; a zlib_message has already - * been output. - */ - zlib_end(&zlib); - return 0; - } - - /* Optimize window bits or fix a too-far-back error. min_bits and - * max_bits have been set appropriately, ok_bits records the bit value - * known to work. - */ - while (min_bits < max_bits || max_bits < zlib.ok_bits/*if 16*/) - { - int test_bits = (min_bits + max_bits) >> 1; - - if (zlib_reset(&zlib, test_bits)) - { - file_setpos(file, &start_pos); - rc = zlib_run(&zlib); - - switch (rc) - { - case ZLIB_TOO_FAR_BACK: - min_bits = test_bits+1; - if (min_bits > max_bits) - { - /* This happens when the stream really is damaged and it - * contains a distance code that addresses bytes before - * the start of the uncompressed data. - */ - assert(test_bits == 15); - - /* Output the error that wasn't output before: */ - if (zlib.z.msg == NULL) - zlib.z.msg = PNGZ_MSG_CAST( - "invalid distance too far back"); - zlib_message(&zlib, 0/*stream error*/); - zlib_end(&zlib); - return 0; - } - break; - - case ZLIB_STREAM_END: /* success */ - max_bits = test_bits; - break; - - default: - /* A fatal error; this happens if a too-far-back error was - * hiding a more serious error, zlib_advance has already - * output a zlib_message. - */ - zlib_end(&zlib); - return 0; - } - } - - else /* inflateReset2 failed */ - { - zlib_end(&zlib); - return 0; - } - } - - /* The loop guarantees this */ - assert(zlib.ok_bits == max_bits); - zlib_end(&zlib); - return 1; - } - - else /* zlib initialization failed - skip the chunk */ - { - zlib_end(&zlib); - return 0; - } -} - -/***************************** LIBPNG CALLBACKS *******************************/ -/* The strategy here is to run a regular libpng PNG file read but examine the - * input data (from the file) before passing it to libpng so as to be aware of - * the state we expect libpng to be in. Warning and error callbacks are also - * intercepted so that they can be quieted and interpreted. Interpretation - * depends on a somewhat risky string match for known error messages; let us - * hope that this can be fixed in the next version of libpng. - * - * The control structure is pointed to by the libpng error pointer. It contains - * that set of structures which must persist across multiple read callbacks, - * which is pretty much everything except the 'zlib' control structure. - * - * The file structure is instantiated in the caller of the per-file routine, but - * the per-file routine contains the chunk and IDAT control structures. - */ -/* The three routines read_chunk, process_chunk and sync_stream can only be - * called via a call to read_chunk and only exit at a return from process_chunk. - * These routines could have been written as one confusing large routine, - * instead this code relies on the compiler to do tail call elimination. The - * possible calls are as follows: - * - * read_chunk - * -> sync_stream - * -> process_chunk - * -> process_chunk - * -> read_chunk - * returns - */ -static void read_chunk(struct file *file); -static void -process_chunk(struct file *file, png_uint_32 file_crc, png_uint_32 next_length, - png_uint_32 next_type) - /* Called when the chunk data has been read, next_length and next_type - * will be set for the next chunk (or 0 if this is IEND). - * - * When this routine returns, chunk_length and chunk_type will be set for the - * next chunk to write because if a chunk is skipped this return calls back - * to read_chunk. - */ -{ - const png_uint_32 type = file->type; - - if (file->global->verbose > 1) - { - fputs(" ", stderr); - type_name(file->type, stderr); - fprintf(stderr, " %lu 0x%.8x 0x%.8x\n", (unsigned long)file->length, - file->crc ^ 0xffffffff, file_crc); - } - - /* The basic structure seems correct but the CRC may not match, in this - * case assume that it is simply a bad CRC, either wrongly calculated or - * because of damaged stream data. - */ - if ((file->crc ^ 0xffffffff) != file_crc) - { - /* The behavior is set by the 'skip' setting; if it is anything other - * than SKIP_BAD_CRC ignore the bad CRC and return the chunk, with a - * corrected CRC and possibly processed, to libpng. Otherwise skip the - * chunk, which will result in a fatal error if the chunk is critical. - */ - file->status_code |= CRC_ERROR; - - /* Ignore the bad CRC */ - if (file->global->skip != SKIP_BAD_CRC) - type_message(file, type, "bad CRC"); - - /* This will cause an IEND with a bad CRC to stop */ - else if (CRITICAL(type)) - stop(file, READ_ERROR_CODE, "bad CRC in critical chunk"); - - else - { - type_message(file, type, "skipped: bad CRC"); - - /* NOTE: this cannot be reached for IEND because it is critical. */ - goto skip_chunk; - } - } - - /* Check for other 'skip' cases and handle these; these only apply to - * ancillary chunks (and not tRNS, which should probably have been a critical - * chunk.) - */ - if (skip_chunk_type(file->global, type)) - goto skip_chunk; - - /* The chunk may still be skipped if problems are detected in the LZ data, - * however the LZ data check requires a chunk. Handle this by instantiating - * a chunk unless an IDAT is already instantiated (IDAT control structures - * instantiate their own chunk.) - */ - if (type != png_IDAT) - file->alloc(file, 0/*chunk*/); - - else if (file->idat == NULL) - file->alloc(file, 1/*IDAT*/); - - else - { - /* The chunk length must be updated for process_IDAT */ - assert(file->chunk != NULL); - assert(file->chunk->chunk_type == png_IDAT); - file->chunk->chunk_length = file->length; - } - - /* Record the 'next' information too, now that the original values for - * this chunk have been copied. Notice that the IDAT chunks only make a - * copy of the position of the first chunk, this is fine - process_IDAT does - * not need the position of this chunk. - */ - file->length = next_length; - file->type = next_type; - getpos(file); - - /* Do per-type processing, note that if this code does not return from the - * function the chunk will be skipped. The rewrite is cancelled here so that - * it can be set in the per-chunk processing. - */ - file->chunk->rewrite_length = 0; - file->chunk->rewrite_offset = 0; - switch (type) - { - default: - return; - - case png_IHDR: - /* Read this now and update the control structure with the information - * it contains. The header is validated completely to ensure this is a - * PNG. - */ - { - struct chunk *chunk = file->chunk; - - if (chunk->chunk_length != 13) - stop_invalid(file, "IHDR length"); - - /* Read all the IHDR information and validate it. */ - setpos(chunk); - file->width = reread_4(file); - file->height = reread_4(file); - file->bit_depth = reread_byte(file); - file->color_type = reread_byte(file); - file->compression_method = reread_byte(file); - file->filter_method = reread_byte(file); - file->interlace_method = reread_byte(file); - - /* This validates all the fields, and calls stop_invalid if - * there is a problem. - */ - calc_image_size(file); - } - return; - - /* Ancillary chunks that require further processing: */ - case png_zTXt: case png_iCCP: - if (process_zTXt_iCCP(file)) - return; - chunk_end(&file->chunk); - file_setpos(file, &file->data_pos); - break; - - case png_iTXt: - if (process_iTXt(file)) - return; - chunk_end(&file->chunk); - file_setpos(file, &file->data_pos); - break; - - case png_IDAT: - if (process_IDAT(file)) - return; - /* First pass: */ - assert(next_type == png_IDAT); - break; - } - - /* Control reaches this point if the chunk must be skipped. For chunks other - * than IDAT this means that the zlib compressed data is fatally damanged and - * the chunk will not be passed to libpng. For IDAT it means that the end of - * the IDAT stream has not yet been reached and we must handle the next - * (IDAT) chunk. If the LZ data in an IDAT stream cannot be read 'stop' must - * be used to halt parsing of the PNG. - */ - read_chunk(file); - return; - - /* This is the generic code to skip the current chunk; simply jump to the - * next one. - */ -skip_chunk: - file->length = next_length; - file->type = next_type; - getpos(file); - read_chunk(file); -} - -static png_uint_32 -get32(png_bytep buffer, int offset) - /* Read a 32-bit value from an 8-byte circular buffer (used only below). - */ -{ - return - (buffer[ offset & 7] << 24) + - (buffer[(offset+1) & 7] << 16) + - (buffer[(offset+2) & 7] << 8) + - (buffer[(offset+3) & 7] ); -} - -static void -sync_stream(struct file *file) - /* The stream seems to be messed up, attempt to resync from the current chunk - * header. Executes stop on a fatal error, otherwise calls process_chunk. - */ -{ - png_uint_32 file_crc; - - file->status_code |= STREAM_ERROR; - - if (file->global->verbose) - { - fputs(" SYNC ", stderr); - type_name(file->type, stderr); - putc('\n', stderr); - } - - /* Return to the start of the chunk data */ - file_setpos(file, &file->data_pos); - file->read_count = 8; - - if (read_4(file, &file_crc) == 4) /* else completely truncated */ - { - /* Ignore the recorded chunk length, proceed through the data looking for - * a leading sequence of bytes that match the CRC in the following four - * bytes. Each time a match is found check the next 8 bytes for a valid - * length, chunk-type pair. - */ - png_uint_32 length; - png_uint_32 type = file->type; - png_uint_32 crc = crc_init_4(type); - png_byte buffer[8]; - unsigned int nread = 0, nused = 0; - - for (length=0; length <= 0x7fffffff; ++length) - { - int ch; - - if ((crc ^ 0xffffffff) == file_crc) - { - /* A match on the CRC; for IEND this is sufficient, but for anything - * else expect a following chunk header. - */ - if (type == png_IEND) - { - file->length = length; - process_chunk(file, file_crc, 0, 0); - return; - } - - else - { - /* Need 8 bytes */ - while (nread < 8+nused) - { - ch = read_byte(file); - if (ch == EOF) - goto truncated; - buffer[(nread++) & 7] = (png_byte)ch; - } - - /* Prevent overflow */ - nread -= nused & ~7; - nused -= nused & ~7; /* or, nused &= 7 ;-) */ - - /* Examine the 8 bytes for a valid chunk header. */ - { - png_uint_32 next_length = get32(buffer, nused); - - if (next_length < 0x7fffffff) - { - png_uint_32 next_type = get32(buffer, nused+4); - - if (chunk_type_valid(next_type)) - { - file->read_count -= 8; - process_chunk(file, file_crc, next_length, next_type); - return; - } - } - - /* Not valid, keep going. */ - } - } - } - - /* This catches up with the circular buffer which gets filled above - * while checking a chunk header. This code is slightly tricky - if - * the chunk_type is IEND the buffer will never be used, if it is not - * the code will always read ahead exactly 8 bytes and pass this on to - * process_chunk. So the invariant that IEND leaves the file position - * after the IEND CRC and other chunk leave it after the *next* chunk - * header is not broken. - */ - if (nread <= nused) - { - ch = read_byte(file); - - if (ch == EOF) - goto truncated; - } - - else - ch = buffer[(++nused) & 7]; - - crc = crc_one_byte(crc, file_crc >> 24); - file_crc = (file_crc << 8) + ch; - } - - /* Control gets to here if when 0x7fffffff bytes (plus 8) have been read, - * ok, treat this as a damaged stream too: - */ - } - -truncated: - stop(file, READ_ERROR_CODE, "damaged PNG stream"); -} - -static void -read_chunk(struct file *file) - /* On entry file::data_pos must be set to the position of the first byte - * of the chunk data *and* the input file must be at this position. This - * routine (via process_chunk) instantiates a chunk or IDAT control structure - * based on file::length and file::type and also resets these fields and - * file::data_pos for the chunk after this one. For an IDAT chunk the whole - * stream of IDATs will be read, until something other than an IDAT is - * encountered, and the file fields will be set for the chunk after the end - * of the stream of IDATs. - * - * For IEND the file::type field will be set to 0, and nothing beyond the end - * of the IEND chunk will have been read. - */ -{ - png_uint_32 length = file->length; - png_uint_32 type = file->type; - - /* After IEND file::type is set to 0, if libpng attempts to read - * more data at this point this is a bug in libpng. - */ - if (type == 0) - stop(file, UNEXPECTED_ERROR_CODE, "read beyond IEND"); - - if (file->global->verbose > 2) - { - fputs(" ", stderr); - type_name(type, stderr); - fprintf(stderr, " %lu\n", (unsigned long)length); - } - - /* Start the read_crc calculation with the chunk type, then read to the end - * of the chunk data (without processing it in any way) to check that it is - * all there and calculate the CRC. - */ - file->crc = crc_init_4(type); - if (crc_read_many(file, length)) /* else it was truncated */ - { - png_uint_32 file_crc; /* CRC read from file */ - unsigned int nread = read_4(file, &file_crc); - - if (nread == 4) - { - if (type != png_IEND) /* do not read beyond IEND */ - { - png_uint_32 next_length; - - nread += read_4(file, &next_length); - if (nread == 8 && next_length <= 0x7fffffff) - { - png_uint_32 next_type; - - nread += read_4(file, &next_type); - - if (nread == 12 && chunk_type_valid(next_type)) - { - /* Adjust the read count back to the correct value for this - * chunk. - */ - file->read_count -= 8; - process_chunk(file, file_crc, next_length, next_type); - return; - } - } - } - - else /* IEND */ - { - process_chunk(file, file_crc, 0, 0); - return; - } - } - } - - /* Control gets to here if the the stream seems invalid or damaged in some - * way. Either there was a problem reading all the expected data (this - * chunk's data, its CRC and the length and type of the next chunk) or the - * next chunk length/type are invalid. Notice that the cases that end up - * here all correspond to cases that would otherwise terminate the read of - * the PNG file. - */ - sync_stream(file); -} - -/* This returns a file* from a png_struct in an implementation specific way. */ -static struct file *get_control(png_const_structrp png_ptr); - -static void PNGCBAPI -error_handler(png_structp png_ptr, png_const_charp message) -{ - stop(get_control(png_ptr), LIBPNG_ERROR_CODE, message); -} - -static void PNGCBAPI -warning_handler(png_structp png_ptr, png_const_charp message) -{ - struct file *file = get_control(png_ptr); - - if (file->global->warnings) - emit_error(file, LIBPNG_WARNING_CODE, message); -} - -/* Read callback - this is where the work gets done to check the stream before - * passing it to libpng - */ -static void PNGCBAPI -read_callback(png_structp png_ptr, png_bytep buffer, size_t count) - /* Return 'count' bytes to libpng in 'buffer' */ -{ - struct file *file = get_control(png_ptr); - png_uint_32 type, length; /* For the chunk be *WRITTEN* */ - struct chunk *chunk; - - /* libpng should always ask for at least one byte */ - if (count == 0) - stop(file, UNEXPECTED_ERROR_CODE, "read callback for 0 bytes"); - - /* The callback always reads ahead by 8 bytes - the signature or chunk header - * - these bytes are stored in chunk_length and chunk_type. This block is - * executed once for the signature and once for the first chunk right at the - * start. - */ - if (file->read_count < 8) - { - assert(file->read_count == 0); - assert((file->status_code & TRUNCATED) == 0); - - (void)read_4(file, &file->length); - - if (file->read_count == 4) - (void)read_4(file, &file->type); - - if (file->read_count < 8) - { - assert((file->status_code & TRUNCATED) != 0); - stop(file, READ_ERROR_CODE, "not a PNG (too short)"); - } - - if (file->state == STATE_SIGNATURE) - { - if (file->length != sig1 || file->type != sig2) - stop(file, LIBPNG_ERROR_CODE, "not a PNG (signature)"); - - /* Else write it (this is the initialization of write_count, prior to - * this it contains CLEAR garbage.) - */ - file->write_count = 0; - } - - else - { - assert(file->state == STATE_CHUNKS); - - /* The first chunk must be a well formed IHDR (this could be relaxed to - * use the checks in process_chunk, but that seems unnecessary.) - */ - if (file->length != 13 || file->type != png_IHDR) - stop(file, LIBPNG_ERROR_CODE, "not a PNG (IHDR)"); - - /* The position of the data must be stored too */ - getpos(file); - } - } - - /* Retrieve previous state (because the read callbacks are made pretty much - * byte-by-byte in the sequential reader prior to 1.7). - */ - chunk = file->chunk; - - if (chunk != NULL) - { - length = chunk->chunk_length; - type = chunk->chunk_type; - } - - else - { - /* This is the signature case; for IDAT and other chunks these values will - * be overwritten when read_chunk is called below. - */ - length = file->length; - type = file->type; - } - - do - { - png_uint_32 b; - - /* Complete the read of a chunk; as a side effect this also instantiates - * a chunk control structure and sets the file length/type/data_pos fields - * for the *NEXT* chunk header. - * - * NOTE: at an IDAT any following IDAT chunks will also be read and the - * next_ fields will refer to the chunk after the last IDAT. - * - * NOTE: read_chunk only returns when it has read a chunk that must now be - * written. - */ - if (file->state != STATE_SIGNATURE && chunk == NULL) - { - assert(file->read_count == 8); - assert(file->idat == NULL); - read_chunk(file); - chunk = file->chunk; - assert(chunk != NULL); - - /* Do the initialization that was not done before. */ - length = chunk->chunk_length; - type = chunk->chunk_type; - - /* And start writing the new chunk. */ - file->write_count = 0; - } - - /* The chunk_ fields describe a chunk that must be written, or hold the - * signature. Write the header first. In the signature case this - * rewrites the signature. - */ - switch (file->write_count) - { - case 0: b = length >> 24; break; - case 1: b = length >> 16; break; - case 2: b = length >> 8; break; - case 3: b = length ; break; - - case 4: b = type >> 24; break; - case 5: b = type >> 16; break; - case 6: b = type >> 8; break; - case 7: b = type ; break; - - case 8: - /* The header has been written. If this is really the signature - * that's all that is required and we can go to normal chunk - * processing. - */ - if (file->state == STATE_SIGNATURE) - { - /* The signature has been written, the tail call to read_callback - * below (it's just a goto to the start with a decent compiler) - * will read the IHDR header ahead and validate it. - */ - assert(length == sig1 && type == sig2); - file->read_count = 0; /* Forces a header read */ - file->state = STATE_CHUNKS; /* IHDR: checked above */ - read_callback(png_ptr, buffer, count); - return; - } - - else - { - assert(chunk != NULL); - - /* Set up for write, notice that repositioning the input stream - * is only necessary if something is to be read from it. Also - * notice that for the IDAT stream this must only happen once - - * on the first IDAT - to get back to the start of the list and - * this is done inside process_IDAT: - */ - chunk->write_crc = crc_init_4(type); - if (file->state != STATE_IDAT && length > 0) - setpos(chunk); - } - /* FALL THROUGH */ - - default: - assert(chunk != NULL); - - /* NOTE: the arithmetic below overflows and gives a large positive - * png_uint_32 value until the whole chunk data has been written. - */ - switch (file->write_count - length) - { - /* Write the chunk data, normally this just comes from - * the file. The only exception is for that part of a - * chunk which is zlib data and which must be rewritten, - * and IDAT chunks which can be completely - * reconstructed. - */ - default: - if (file->state == STATE_IDAT) - { - struct IDAT *idat = file->idat; - - assert(idat != NULL); - - /* Read an IDAT byte from the input stream of IDAT chunks. - * Because the IDAT stream can be re-chunked this stream is - * held in the struct IDAT members. The chunk members, in - * particular chunk_length (and therefore the length local) - * refer to the output chunk. - */ - while (idat->idat_index >= idat->idat_length) - { - /* Advance one chunk */ - struct IDAT_list *cur = idat->idat_cur; - - assert(idat->idat_index == idat->idat_length); - assert(cur != NULL && cur->count > 0); - - /* NOTE: IDAT_list::count here, not IDAT_list::length */ - if (++(idat->idat_count) >= cur->count) - { - assert(idat->idat_count == cur->count); - - /* Move on to the next IDAT_list: */ - cur = cur->next; - - /* This is an internal error - read beyond the end of - * the pre-calculated stream. - */ - if (cur == NULL || cur->count == 0) - stop(file, UNEXPECTED_ERROR_CODE, - "read beyond end of IDAT"); - - idat->idat_count = 0; - idat->idat_cur = cur; - } - - idat->idat_index = 0; - /* Zero length IDAT chunks are permitted, so the length - * here may be 0. - */ - idat->idat_length = cur->lengths[idat->idat_count]; - - /* And skip 12 bytes to the next chunk data */ - skip_12(file); - } - - /* The index is always that of the next byte, the rest of - * the information is always the current IDAT chunk and the - * current list. - */ - ++(idat->idat_index); - } - - /* Read the byte from the stream. */ - b = reread_byte(file); - - /* If the byte must be rewritten handle that here */ - if (chunk->rewrite_length > 0) - { - if (chunk->rewrite_offset > 0) - --(chunk->rewrite_offset); - - else - { - b = chunk->rewrite_buffer[0]; - memmove(chunk->rewrite_buffer, chunk->rewrite_buffer+1, - (sizeof chunk->rewrite_buffer)- - (sizeof chunk->rewrite_buffer[0])); - - --(chunk->rewrite_length); - } - } - - chunk->write_crc = crc_one_byte(chunk->write_crc, b); - break; - - /* The CRC is written at: - * - * chunk_write == chunk_length+8..chunk_length+11 - * - * so 8 to 11. The CRC is not (yet) conditioned. - */ - case 8: b = chunk->write_crc >> 24; goto write_crc; - case 9: b = chunk->write_crc >> 16; goto write_crc; - case 10: b = chunk->write_crc >> 8; goto write_crc; - case 11: - /* This must happen before the chunk_end below: */ - b = chunk->write_crc; - - if (file->global->verbose > 2) - { - fputs(" ", stderr); - type_name(type, stderr); - fprintf(stderr, " %lu 0x%.8x\n", (unsigned long)length, - chunk->write_crc ^ 0xffffffff); - } - - /* The IDAT stream is written without a call to read_chunk - * until the end is reached. rechunk_length() calculates the - * length of the output chunks. Control gets to this point at - * the end of an *output* chunk - the length calculated by - * rechunk_length. If this corresponds to the end of the - * input stream stop writing IDAT chunks, otherwise continue. - */ - if (file->state == STATE_IDAT && - (file->idat->idat_index < file->idat->idat_length || - 1+file->idat->idat_count < file->idat->idat_cur->count || - file->idat->idat_cur != file->idat->idat_list_tail)) - { - /* Write another IDAT chunk. Call rechunk_length to - * calculate the length required. - */ - length = chunk->chunk_length = rechunk_length(file->idat); - assert(type == png_IDAT); - file->write_count = 0; /* for the new chunk */ - --(file->write_count); /* fake out the increment below */ - } - - else - { - /* Entered at the end of a non-IDAT chunk and at the end of - * the IDAT stream. The rewrite should have been cleared. - */ - if (chunk->rewrite_length > 0 || chunk->rewrite_offset > 0) - stop(file, UNEXPECTED_ERROR_CODE, "pending rewrite"); - - /* This is the last byte so reset chunk_read for the next - * chunk and move the input file to the position after the - * *next* chunk header if required. - */ - file->read_count = 8; - file_setpos(file, &file->data_pos); - - if (file->idat == NULL) - chunk_end(&file->chunk); - - else - IDAT_end(&file->idat); - } - - write_crc: - b ^= 0xff; /* conditioning */ - break; - } - break; - } - - /* Write one byte */ - b &= 0xff; - *buffer++ = (png_byte)b; - --count; - write_byte(file, (png_byte)b); /* increments chunk_write */ - } - while (count > 0); -} - -/* Bundle the file and an uninitialized chunk and IDAT control structure - * together to allow implementation of the chunk/IDAT allocate routine. - */ -struct control -{ - struct file file; - struct chunk chunk; - struct IDAT idat; -}; - -static int -control_end(struct control *control) -{ - return file_end(&control->file); -} - -static struct file * -get_control(png_const_structrp png_ptr) -{ - /* This just returns the (file*). The chunk and idat control structures - * don't always exist. - */ - struct control *control = png_voidcast(struct control*, - png_get_error_ptr(png_ptr)); - return &control->file; -} - -static void -allocate(struct file *file, int allocate_idat) -{ - struct control *control = png_voidcast(struct control*, file->alloc_ptr); - - if (allocate_idat) - { - assert(file->idat == NULL); - IDAT_init(&control->idat, file); - } - - else /* chunk */ - { - assert(file->chunk == NULL); - chunk_init(&control->chunk, file); - } -} - -static int -control_init(struct control *control, struct global *global, - const char *file_name, const char *out_name) - /* This wraps file_init(&control::file) and simply returns the result from - * file_init. - */ -{ - return file_init(&control->file, global, file_name, out_name, control, - allocate); -} - -static int -read_png(struct control *control) - /* Read a PNG, return 0 on success else an error (status) code; a bit mask as - * defined for file::status_code as above. - */ -{ - png_structp png_ptr; - png_infop info_ptr = NULL; - volatile png_bytep row = NULL, display = NULL; - volatile int rc; - - png_ptr = png_create_read_struct(png_get_libpng_ver(NULL), control, - error_handler, warning_handler); - - if (png_ptr == NULL) - { - /* This is not really expected. */ - log_error(&control->file, LIBPNG_ERROR_CODE, "OOM allocating png_struct"); - control->file.status_code |= INTERNAL_ERROR; - return LIBPNG_ERROR_CODE; - } - - rc = setjmp(control->file.jmpbuf); - if (rc == 0) - { - png_set_read_fn(png_ptr, control, read_callback); - - info_ptr = png_create_info_struct(png_ptr); - if (info_ptr == NULL) - png_error(png_ptr, "OOM allocating info structure"); - - if (control->file.global->verbose) - fprintf(stderr, " INFO\n"); - - png_read_info(png_ptr, info_ptr); - - { - png_size_t rowbytes = png_get_rowbytes(png_ptr, info_ptr); - - row = png_voidcast(png_byte*, malloc(rowbytes)); - display = png_voidcast(png_byte*, malloc(rowbytes)); - - if (row == NULL || display == NULL) - png_error(png_ptr, "OOM allocating row buffers"); - - { - png_uint_32 height = png_get_image_height(png_ptr, info_ptr); - int passes = png_set_interlace_handling(png_ptr); - int pass; - - png_start_read_image(png_ptr); - - for (pass = 0; pass < passes; ++pass) - { - png_uint_32 y = height; - - /* NOTE: this trashes the row each time; interlace handling won't - * work, but this avoids memory thrashing for speed testing. - */ - while (y-- > 0) - png_read_row(png_ptr, row, display); - } - } - } - - if (control->file.global->verbose) - fprintf(stderr, " END\n"); - - /* Make sure to read to the end of the file: */ - png_read_end(png_ptr, info_ptr); - } - - png_destroy_read_struct(&png_ptr, &info_ptr, NULL); - if (row != NULL) free(row); - if (display != NULL) free(display); - return rc; -} - -static int -one_file(struct global *global, const char *file_name, const char *out_name) -{ - int rc; - struct control control; - - if (global->verbose) - fprintf(stderr, "FILE %s -> %s\n", file_name, - out_name ? out_name : "<none>"); - - /* Although control_init can return a failure code the structure is always - * initialized, so control_end can be used to accumulate any status codes. - */ - rc = control_init(&control, global, file_name, out_name); - - if (rc == 0) - rc = read_png(&control); - - rc |= control_end(&control); - - return rc; -} - -static void -usage(const char *prog) -{ - /* ANSI C-90 limits strings to 509 characters, so use a string array: */ - size_t i; - static const char *usage_string[] = { -" Tests, optimizes and optionally fixes the zlib header in PNG files.", -" Optionally, when fixing, strips ancilliary chunks from the file.", -0, -"OPTIONS", -" OPERATION", -" By default files are just checked for readability with a summary of the", -" of zlib issues founds for each compressed chunk and the IDAT stream in", -" the file.", -" --optimize (-o):", -" Find the smallest deflate window size for the compressed data.", -" --strip=[none|crc|unsafe|unused|transform|color|all]:", -" none (default): Retain all chunks.", -" crc: Remove chunks with a bad CRC.", -" unsafe: Remove chunks that may be unsafe to retain if the image data", -" is modified. This is set automatically if --max is given but", -" may be cancelled by a later --strip=none.", -" unused: Remove chunks not used by libpng when decoding an image.", -" This retains any chunks that might be used by libpng image", -" transformations.", -" transform: unused+bKGD.", -" color: transform+iCCP and cHRM.", -" all: color+gAMA and sRGB.", -" Only ancillary chunks are ever removed. In addition the tRNS and sBIT", -" chunks are never removed as they affect exact interpretation of the", -" image pixel values. The following known chunks are treated specially", -" by the above options:", -" gAMA, sRGB [all]: These specify the gamma encoding used for the pixel", -" values.", -" cHRM, iCCP [color]: These specify how colors are encoded. iCCP also", -" specifies the exact encoding of a pixel value however in practice", -" most programs will ignore it.", -" bKGD [transform]: This is used by libpng transforms." -" --max=<number>:", -" Use IDAT chunks sized <number>. If no number is given the the IDAT", -" chunks will be the maximum size permitted; 2^31-1 bytes. If the option", -" is omitted the original chunk sizes will not be changed. When the", -" option is given --strip=unsafe is set automatically, this may be", -" cancelled if you know that all unknown unsafe-to-copy chunks really are", -" safe to copy across an IDAT size change. This is true of all chunks", -" that have ever been formally proposed as PNG extensions.", -" MESSAGES", -" By default the program only outputs summaries for each file.", -" --quiet (-q):", -" Do not output the summaries except for files which cannot be read. With", -" two --quiets these are not output either.", -" --errors (-e):", -" Output errors from libpng and the program (except too-far-back).", -" --warnings (-w):", -" Output warnings from libpng.", -" OUTPUT", -" By default nothing is written.", -" --out=<file>:", -" Write the optimized/corrected version of the next PNG to <file>. This", -" overrides the following two options", -" --suffix=<suffix>:", -" Set --out=<name><suffix> for all following files unless overridden on", -" a per-file basis by explicit --out.", -" --prefix=<prefix>:", -" Set --out=<prefix><name> for all the following files unless overridden", -" on a per-file basis by explicit --out.", -" These two options can be used together to produce a suffix and prefix.", -" INTERNAL OPTIONS", -#if 0 /*NYI*/ -#ifdef PNG_MAXIMUM_INFLATE_WINDOW -" --test:", -" Test the PNG_MAXIMUM_INFLATE_WINDOW option. Setting this disables", -" output as this would produce a broken file.", -#endif -#endif -0, -"EXIT CODES", -" *** SUBJECT TO CHANGE ***", -" The program exit code is value in the range 0..127 holding a bit mask of", -" the following codes. Notice that the results for each file are combined", -" together - check one file at a time to get a meaningful error code!", -" 0x01: The zlib too-far-back error existed in at least one chunk.", -" 0x02: At least once chunk had a CRC error.", -" 0x04: A chunk length was incorrect.", -" 0x08: The file was truncated.", -" Errors less than 16 are potentially recoverable, for a single file if the", -" exit code is less than 16 the file could be read (with corrections if a", -" non-zero code is returned).", -" 0x10: The file could not be read, even with corrections.", -" 0x20: The output file could not be written.", -" 0x40: An unexpected, potentially internal, error occured.", -" If the command line arguments are incorrect the program exits with exit", -" 255. Some older operating systems only support 7-bit exit codes, on those", -" systems it is suggested that this program is first tested by supplying", -" invalid arguments.", -0, -"DESCRIPTION", -" " PROGRAM_NAME ":", -" checks each PNG file on the command line for errors. By default errors are", -" not output and the program just returns an exit code and prints a summary.", -" With the --quiet (-q) option the summaries are suppressed too and the", -" program only outputs unexpected errors (internal errors and file open", -" errors).", -" Various known problems in PNG files are fixed while the file is being read", -" The exit code says what problems were fixed. In particular the zlib error:", -0, -" \"invalid distance too far back\"", -0, -" caused by an incorrect optimization of a zlib stream is fixed in any", -" compressed chunk in which it is encountered. An integrity problem of the", -" PNG stream caused by a bug in libpng which wrote an incorrect chunk length", -" is also fixed. Chunk CRC errors are automatically fixed up.", -0, -" Setting one of the \"OUTPUT\" options causes the possibly modified file to", -" be written to a new file.", -0, -" Notice that some PNG files with the zlib optimization problem can still be", -" read by libpng under some circumstances. This program will still detect", -" and, if requested, correct the error.", -0, -" The program will reliably process all files on the command line unless", -" either an invalid argument causes the usage message (this message) to be", -" produced or the program crashes.", -0, -" The summary lines describe issues encountered with the zlib compressed", -" stream of a chunk. They have the following format, which is SUBJECT TO", -" CHANGE in the future:", -0, -" chunk reason comp-level p1 p2 p3 p4 file", -0, -" p1 through p4 vary according to the 'reason'. There are always 8 space", -" separated fields. Reasons specific formats are:", -0, -" chunk ERR status code read-errno write-errno message file", -" chunk SKP comp-level file-bits zlib-rc compressed message file", -" chunk ??? comp-level file-bits ok-bits compressed uncompress file", -0, -" The various fields are", -0, -"$1 chunk: The chunk type of a chunk in the file or 'HEAD' if a problem", -" is reported by libpng at the start of the IDAT stream.", -"$2 reason: One of:", -" CHK: A zlib header checksum was detected and fixed.", -" TFB: The zlib too far back error was detected and fixed.", -" OK : No errors were detected in the zlib stream and optimization", -" was not requested, or was not possible.", -" OPT: The zlib stream window bits value could be improved (and was).", -" SKP: The chunk was skipped because of a zlib issue (zlib-rc) with", -" explanation 'message'", -" ERR: The read of the file was aborted. The parameters explain why.", -"$3 status: For 'ERR' the accumulate status code from 'EXIT CODES' above.", -" This is printed as a 2 digit hexadecimal value", -" comp-level: The recorded compression level (FLEVEL) of a zlib stream", -" expressed as a string {supfast,stdfast,default,maximum}", -"$4 code: The file exit code; where stop was called, as a fairly terse", -" string {warning,libpng,zlib,invalid,read,write,unexpected}.", -" file-bits: The zlib window bits recorded in the file.", -"$5 read-errno: A system errno value from a read translated by strerror(3).", -" zlib-rc: A zlib return code as a string (see zlib.h).", -" ok-bits: The smallest zlib window bits value that works.", -"$6 write-errno:A system errno value from a write translated by strerror(3).", -" compressed: The count of compressed bytes in the zlib stream, when the", -" reason is 'SKP'; this is a count of the bytes read from the", -" stream when the fatal error was encountered.", -"$7 message: An error message (spaces replaced by _, as in all parameters),", -" uncompress: The count of bytes from uncompressing the zlib stream; this", -" may not be the same as the number of bytes in the image.", -"$8 file: The name of the file (this may contain spaces).", -}; - - fprintf(stderr, "Usage: %s {[options] png-file}\n", prog); - - for (i=0; i < (sizeof usage_string)/(sizeof usage_string[0]); ++i) - { - if (usage_string[i] != 0) - fputs(usage_string[i], stderr); - - fputc('\n', stderr); - } - - exit(255); -} - -int -main(int argc, const char **argv) -{ - const char * prog = *argv; - const char * outfile = NULL; - const char * suffix = NULL; - const char * prefix = NULL; - int done = 0; /* if at least one file is processed */ - struct global global; - - global_init(&global); - - while (--argc > 0) - { - ++argv; - - if (strcmp(*argv, "--debug") == 0) - { - /* To help debugging problems: */ - global.errors = global.warnings = 1; - global.quiet = 0; - global.verbose = 7; - } - - else if (strncmp(*argv, "--max=", 6) == 0) - { - global.idat_max = (png_uint_32)atol(6+*argv); - - if (global.skip < SKIP_UNSAFE) - global.skip = SKIP_UNSAFE; - } - - else if (strcmp(*argv, "--max") == 0) - { - global.idat_max = 0x7fffffff; - - if (global.skip < SKIP_UNSAFE) - global.skip = SKIP_UNSAFE; - } - - else if (strcmp(*argv, "--optimize") == 0 || strcmp(*argv, "-o") == 0) - global.optimize_zlib = 1; - - else if (strncmp(*argv, "--out=", 6) == 0) - outfile = 6+*argv; - - else if (strncmp(*argv, "--suffix=", 9) == 0) - suffix = 9+*argv; - - else if (strncmp(*argv, "--prefix=", 9) == 0) - prefix = 9+*argv; - - else if (strcmp(*argv, "--strip=none") == 0) - global.skip = SKIP_NONE; - - else if (strcmp(*argv, "--strip=crc") == 0) - global.skip = SKIP_BAD_CRC; - - else if (strcmp(*argv, "--strip=unsafe") == 0) - global.skip = SKIP_UNSAFE; - - else if (strcmp(*argv, "--strip=unused") == 0) - global.skip = SKIP_UNUSED; - - else if (strcmp(*argv, "--strip=transform") == 0) - global.skip = SKIP_TRANSFORM; - - else if (strcmp(*argv, "--strip=color") == 0) - global.skip = SKIP_COLOR; - - else if (strcmp(*argv, "--strip=all") == 0) - global.skip = SKIP_ALL; - - else if (strcmp(*argv, "--errors") == 0 || strcmp(*argv, "-e") == 0) - global.errors = 1; - - else if (strcmp(*argv, "--warnings") == 0 || strcmp(*argv, "-w") == 0) - global.warnings = 1; - - else if (strcmp(*argv, "--quiet") == 0 || strcmp(*argv, "-q") == 0) - { - if (global.quiet) - global.quiet = 2; - - else - global.quiet = 1; - } - - else if (strcmp(*argv, "--verbose") == 0 || strcmp(*argv, "-v") == 0) - ++global.verbose; - -#if 0 - /* NYI */ -# ifdef PNG_MAXIMUM_INFLATE_WINDOW - else if (strcmp(*argv, "--test") == 0) - ++set_option; -# endif -#endif - - else if ((*argv)[0] == '-') - usage(prog); - - else - { - size_t outlen = strlen(*argv); - char temp_name[FILENAME_MAX+1]; - - if (outfile == NULL) /* else this takes precedence */ - { - /* Consider the prefix/suffix options */ - if (prefix != NULL) - { - size_t prefixlen = strlen(prefix); - - if (prefixlen+outlen > FILENAME_MAX) - { - fprintf(stderr, "%s: output file name too long: %s%s%s\n", - prog, prefix, *argv, suffix ? suffix : ""); - global.status_code |= WRITE_ERROR; - continue; - } - - memcpy(temp_name, prefix, prefixlen); - memcpy(temp_name+prefixlen, *argv, outlen); - outlen += prefixlen; - outfile = temp_name; - } - - else if (suffix != NULL) - memcpy(temp_name, *argv, outlen); - - temp_name[outlen] = 0; - - if (suffix != NULL) - { - size_t suffixlen = strlen(suffix); - - if (outlen+suffixlen > FILENAME_MAX) - { - fprintf(stderr, "%s: output file name too long: %s%s\n", - prog, *argv, suffix); - global.status_code |= WRITE_ERROR; - continue; - } - - memcpy(temp_name+outlen, suffix, suffixlen); - outlen += suffixlen; - temp_name[outlen] = 0; - outfile = temp_name; - } - } - - (void)one_file(&global, *argv, outfile); - ++done; - outfile = NULL; - } - } - - if (!done) - usage(prog); - - return global_end(&global); -} - -#else /* ZLIB_VERNUM < 0x1240 */ -int -main(void) -{ - fprintf(stderr, - "pngfix needs libpng with a zlib >=1.2.4 (not 0x%x)\n", - ZLIB_VERNUM); - return 77; -} -#endif /* ZLIB_VERNUM */ - -#else /* No read support */ - -int -main(void) -{ - fprintf(stderr, "pngfix does not work without read support\n"); - return 77; -} -#endif /* PNG_READ_SUPPORTED && PNG_EASY_ACCESS_SUPPORTED */ -#else /* No setjmp support */ -int -main(void) -{ - fprintf(stderr, "pngfix does not work without setjmp support\n"); - return 77; -} -#endif /* PNG_SETJMP_SUPPORTED */ - |