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[libpng17] Ported pngfix.c patches from libpng16.

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John Bowler 2013-07-03 07:50:24 -05:00 committed by Glenn Randers-Pehrson
parent f97b2a6cde
commit 23f3e46518
3 changed files with 168 additions and 42 deletions
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1
ANNOUNCE
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@ -341,6 +341,7 @@ Version 1.7.0beta16 [July 3, 2013]
Added perfect hash code generation for lists of PNG chunks. This is
a work in progress; checked in for use in pngfix.c
Ported ARM no-read patch from libpng16.
Ported pngfix.c patches from libpng16.
Send comments/corrections/commendations to png-mng-implement at lists.sf.net
(subscription required; visit

1
CHANGES
View File

@ -4629,6 +4629,7 @@ Version 1.7.0beta16 [July 3, 2013]
Added perfect hash code generation for lists of PNG chunks. This is
a work in progress; checked in for use in pngfix.c
Ported ARM no-read patch from libpng16.
Ported pngfix.c patches from libpng16.
Send comments/corrections/commendations to png-mng-implement at lists.sf.net
(subscription required; visit

208
contrib/tools/pngfix.c
View File

@ -73,6 +73,41 @@
# 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)
@ -80,6 +115,9 @@
/* 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)
/********************************* 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
@ -626,9 +664,11 @@ struct global
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_NON_IMAGE 2 /* Chunks not used by libpng */
# define SKIP_COLOR 3 /* Everything but tRNS, sBIT, gAMA and sRGB */
# define SKIP_ALL 4 /* Everything but tRNS */
# 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 */
@ -679,6 +719,80 @@ global_init(struct global *global)
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;
@ -2644,7 +2758,6 @@ process_chunk(struct file *file, png_uint_32 file_crc, png_uint_32 next_length,
*/
{
const png_uint_32 type = file->type;
int critical = CRITICAL(type);
if (file->global->verbose > 1)
{
@ -2672,7 +2785,7 @@ process_chunk(struct file *file, png_uint_32 file_crc, png_uint_32 next_length,
type_message(file, type, "bad CRC");
/* This will cause an IEND with a bad CRC to stop */
else if (critical)
else if (CRITICAL(type))
stop(file, READ_ERROR_CODE, "bad CRC in critical chunk");
else
@ -2688,32 +2801,8 @@ process_chunk(struct file *file, png_uint_32 file_crc, png_uint_32 next_length,
* ancillary chunks (and not tRNS, which should probably have been a critical
* chunk.)
*/
if (!critical)
{
unsigned int skip = file->global->skip;
/* SKIP_BAD_CRC was handled above: */
if (skip > SKIP_BAD_CRC) switch (type)
{
case png_tRNS: case png_sBIT: /* always handle this */
break;
case png_gAMA: case png_sRGB:
if (skip >= SKIP_ALL)
goto skip_chunk;
break;
case png_cHRM: case png_iCCP:
if (skip >= SKIP_COLOR)
goto skip_chunk;
break;
default:
if (skip >= SKIP_NON_IMAGE)
goto skip_chunk;
break;
}
}
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
@ -2856,6 +2945,7 @@ sync_stream(struct file *file)
/* 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 */
{
@ -3081,10 +3171,10 @@ read_callback(png_structp png_ptr, png_bytep buffer, size_t count)
assert(file->read_count == 0);
assert((file->status_code & TRUNCATED) == 0);
file->read_count = read_4(file, &file->length);
(void)read_4(file, &file->length);
if (file->read_count == 4)
file->read_count += read_4(file, &file->type);
(void)read_4(file, &file->type);
if (file->read_count < 8)
{
@ -3567,18 +3657,36 @@ usage(const char *prog)
" the file.",
" --optimize (-o):",
" Find the smallest deflate window size for the compressed data.",
" --strip=[none|crc|unused|color|all]:",
" none (default): Retain all chunks.",
" --strip=[none|crc|unsafe|unused|transform|color|all]:",
" none: Retain all chunks.",
" crc: Remove chunks with a bad CRC.",
" unused: Remove chunks not used by libpng.",
" color: unused+iCCP and cHRM.",
" 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.",
" The chunks used by libpng are IHDR, PLTE, IEND, tRNS, sBIT plus the",
" colorspace chunks (sRGB, iCCP, gAMA and cHRM).",
" 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.",
" is ommited 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):",
@ -3682,7 +3790,7 @@ usage(const char *prog)
" 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.",
" 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",
@ -3741,11 +3849,21 @@ main(int argc, const char **argv)
}
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;
@ -3764,8 +3882,14 @@ main(int argc, const char **argv)
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_NON_IMAGE;
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;