mirror of
https://git.code.sf.net/p/libpng/code.git
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[libpng16] Fixed undefined behavior in contrib/tools/pngfix.c and added new
strip option. pngfix relied on undefined behavior and even a simple change from gcc to g++ caused it to fail. The new strip option 'unsafe' has been implemented and is the default if --max is given. Option names have been clarified, with --strip=transform now stripping the bKGD chunk, which was stripped previously with --strip=unused. Added all documented chunk types to pngpriv.h
This commit is contained in:
John Bowler
Glenn Randers-Pehrson
parent
497e7319f4
commit
f5f1206778
7
ANNOUNCE
7
ANNOUNCE
@ -115,6 +115,13 @@ Version 1.6.3beta09 [June 27, 2013]
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Version 1.6.3beta10 [July 3, 2013]
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Updated documentation to show default behavior of benign errors correctly.
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Only compile ARM code when PNG_READ_SUPPORTED is defined.
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Fixed undefined behavior in contrib/tools/pngfix.c and added new strip
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option. pngfix relied on undefined behavior and even a simple change from
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gcc to g++ caused it to fail. The new strip option 'unsafe' has been
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implemented and is the default if --max is given. Option names have
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been clarified, with --strip=transform now stripping the bKGD chunk,
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which was stripped previously with --strip=unused.
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Added all documented chunk types to pngpriv.h
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Send comments/corrections/commendations to png-mng-implement at lists.sf.net
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||||
(subscription required; visit
|
||||
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7
CHANGES
7
CHANGES
@ -4599,6 +4599,13 @@ Version 1.6.3beta09 [June 27, 2013]
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Version 1.6.3beta10 [July 3, 2013]
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Updated documentation to show default behavior of benign errors correctly.
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Only compile ARM code when PNG_READ_SUPPORTED is defined.
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Fixed undefined behavior in contrib/tools/pngfix.c and added new strip
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option. pngfix relied on undefined behavior and even a simple change from
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gcc to g++ caused it to fail. The new strip option 'unsafe' has been
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implemented and is the default if --max is given. Option names have
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been clarified, with --strip=transform now stripping the bKGD chunk,
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which was stripped previously with --strip=unused.
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Added all documented chunk types to pngpriv.h
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Send comments/corrections/commendations to png-mng-implement at lists.sf.net
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(subscription required; visit
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||||
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@ -75,38 +75,49 @@
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/* Chunk tags (copied from pngpriv.h) */
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#define PNG_32b(b,s) ((png_uint_32)(b) << (s))
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#define PNG_CHUNK(b1,b2,b3,b4) \
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#define PNG_U32(b1,b2,b3,b4) \
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(PNG_32b(b1,24) | PNG_32b(b2,16) | PNG_32b(b3,8) | PNG_32b(b4,0))
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#define png_IHDR PNG_CHUNK( 73, 72, 68, 82)
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#define png_IDAT PNG_CHUNK( 73, 68, 65, 84)
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#define png_IEND PNG_CHUNK( 73, 69, 78, 68)
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#define png_PLTE PNG_CHUNK( 80, 76, 84, 69)
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#define png_bKGD PNG_CHUNK( 98, 75, 71, 68)
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#define png_cHRM PNG_CHUNK( 99, 72, 82, 77)
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#define png_gAMA PNG_CHUNK(103, 65, 77, 65)
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#define png_hIST PNG_CHUNK(104, 73, 83, 84)
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#define png_iCCP PNG_CHUNK(105, 67, 67, 80)
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#define png_iTXt PNG_CHUNK(105, 84, 88, 116)
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#define png_oFFs PNG_CHUNK(111, 70, 70, 115)
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#define png_pCAL PNG_CHUNK(112, 67, 65, 76)
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#define png_sCAL PNG_CHUNK(115, 67, 65, 76)
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#define png_pHYs PNG_CHUNK(112, 72, 89, 115)
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#define png_sBIT PNG_CHUNK(115, 66, 73, 84)
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#define png_sPLT PNG_CHUNK(115, 80, 76, 84)
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#define png_sRGB PNG_CHUNK(115, 82, 71, 66)
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#define png_sTER PNG_CHUNK(115, 84, 69, 82)
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#define png_tEXt PNG_CHUNK(116, 69, 88, 116)
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#define png_tIME PNG_CHUNK(116, 73, 77, 69)
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#define png_tRNS PNG_CHUNK(116, 82, 78, 83)
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#define png_zTXt PNG_CHUNK(122, 84, 88, 116)
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/* Constants for known chunk types.
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*
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* Copied from ../../pngpriv.h.
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*/
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#define png_IDAT PNG_U32( 73, 68, 65, 84)
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#define png_IEND PNG_U32( 73, 69, 78, 68)
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#define png_IHDR PNG_U32( 73, 72, 68, 82)
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#define png_PLTE PNG_U32( 80, 76, 84, 69)
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#define png_bKGD PNG_U32( 98, 75, 71, 68)
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#define png_cHRM PNG_U32( 99, 72, 82, 77)
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#define png_fRAc PNG_U32(102, 82, 65, 99) /* registered, not defined */
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#define png_gAMA PNG_U32(103, 65, 77, 65)
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#define png_gIFg PNG_U32(103, 73, 70, 103)
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#define png_gIFt PNG_U32(103, 73, 70, 116) /* deprecated */
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#define png_gIFx PNG_U32(103, 73, 70, 120)
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#define png_hIST PNG_U32(104, 73, 83, 84)
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#define png_iCCP PNG_U32(105, 67, 67, 80)
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#define png_iTXt PNG_U32(105, 84, 88, 116)
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#define png_oFFs PNG_U32(111, 70, 70, 115)
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#define png_pCAL PNG_U32(112, 67, 65, 76)
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#define png_pHYs PNG_U32(112, 72, 89, 115)
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#define png_sBIT PNG_U32(115, 66, 73, 84)
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#define png_sCAL PNG_U32(115, 67, 65, 76)
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#define png_sPLT PNG_U32(115, 80, 76, 84)
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#define png_sRGB PNG_U32(115, 82, 71, 66)
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#define png_sTER PNG_U32(115, 84, 69, 82)
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#define png_tEXt PNG_U32(116, 69, 88, 116)
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#define png_tIME PNG_U32(116, 73, 77, 69)
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#define png_tRNS PNG_U32(116, 82, 78, 83)
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#define png_zTXt PNG_U32(122, 84, 88, 116)
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/* The 8 byte signature as a pair of 32 bit quantities */
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#define sig1 PNG_CHUNK(137, 80, 78, 71)
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#define sig2 PNG_CHUNK( 13, 10, 26, 10)
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#define sig1 PNG_U32(137, 80, 78, 71)
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#define sig2 PNG_U32( 13, 10, 26, 10)
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/* Is the chunk critical? */
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#define CRITICAL(chunk) (((chunk) & PNG_CHUNK(32,0,0,0)) == 0)
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#define CRITICAL(chunk) (((chunk) & PNG_U32(32,0,0,0)) == 0)
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/* Is it safe to copy? */
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#define SAFE_TO_COPY(chunk) (((chunk) & PNG_U32(0,0,0,32)) != 0)
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/********************************* UTILITIES **********************************/
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/* UNREACHED is a value to cause an assert to fail. Because of the way the
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@ -540,19 +551,19 @@ chunk_type_valid(png_uint_32 c)
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* 8-bit unit must be in the range 65-90 to be valid. So bit 5
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* must be zero, bit 6 must be set and bit 7 zero.
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*/
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c &= ~PNG_CHUNK(32,32,0,32);
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c &= ~PNG_U32(32,32,0,32);
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t = (c & ~0x1f1f1f1f) ^ 0x40404040;
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/* Subtract 65 for each 8 bit quantity, this must not overflow
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* and each byte must then be in the range 0-25.
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*/
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c -= PNG_CHUNK(65,65,65,65);
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c -= PNG_U32(65,65,65,65);
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t |=c ;
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/* Subtract 26, handling the overflow which should set the top
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* three bits of each byte.
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*/
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c -= PNG_CHUNK(25,25,25,26);
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c -= PNG_U32(25,25,25,26);
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t |= ~c;
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return (t & 0xe0e0e0e0) == 0;
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@ -654,9 +665,11 @@ struct global
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unsigned int skip :3; /* Non-critical chunks to skip */
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# define SKIP_NONE 0
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# define SKIP_BAD_CRC 1 /* Chunks with a bad CRC */
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# define SKIP_NON_IMAGE 2 /* Chunks not used by libpng */
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# define SKIP_COLOR 3 /* Everything but tRNS, sBIT, gAMA and sRGB */
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# define SKIP_ALL 4 /* Everything but tRNS */
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# define SKIP_UNSAFE 2 /* Chunks not safe to copy */
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# define SKIP_UNUSED 3 /* Chunks not used by libpng */
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# define SKIP_TRANSFORM 4 /* Chunks only used in transforms */
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# define SKIP_COLOR 5 /* Everything but tRNS, sBIT, gAMA and sRGB */
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# define SKIP_ALL 6 /* Everything but tRNS and sBIT */
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png_uint_32 idat_max; /* 0 to perform no re-chunking */
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@ -707,6 +720,80 @@ global_init(struct global *global)
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IDAT_list_init(&global->idat_cache);
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}
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static int
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skip_chunk_type(const struct global *global, png_uint_32 type)
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/* Return true if this chunk is to be skipped according to the --strip
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* option. This code needs to recognize all known ancillary chunks in order
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* to handle the --strip=unsafe option.
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*/
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{
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/* Never strip critical chunks: */
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if (CRITICAL(type))
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return 0;
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switch (type)
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{
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/* Chunks that are treated as, effectively, critical because they affect
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* correct interpretation of the pixel values:
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*/
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case png_tRNS: case png_sBIT:
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return 0;
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/* Chunks that specify gamma encoding which should therefore only be
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* removed the the user insists:
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*/
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case png_gAMA: case png_sRGB:
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if (global->skip >= SKIP_ALL)
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return 1;
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return 0;
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/* Chunks that affect color interpretation - not used by libpng and rarely
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* used by applications, but technically still required for correct
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* interpretation of the image data:
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*/
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case png_cHRM: case png_iCCP:
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if (global->skip >= SKIP_COLOR)
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return 1;
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return 0;
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/* Other chunks that are used by libpng in image transformations (as
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* opposed to known chunks that have get/set APIs but are not otherwise
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* used.)
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*/
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case png_bKGD:
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if (global->skip >= SKIP_TRANSFORM)
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return 1;
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return 0;
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/* All other chunks that libpng knows about and affect neither image
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* interpretation nor libpng transforms - chunks that are effectively
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* unused by libpng even though libpng might recognize and store them.
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*/
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case png_fRAc: case png_gIFg: case png_gIFt: case png_gIFx: case png_hIST:
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case png_iTXt: case png_oFFs: case png_pCAL: case png_pHYs: case png_sCAL:
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case png_sPLT: case png_sTER: case png_tEXt: case png_tIME: case png_zTXt:
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if (global->skip >= SKIP_UNUSED)
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return 1;
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return 0;
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/* Chunks that libpng does not know about (notice that this depends on the
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* list above including all known chunks!) The decision here depends on
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* whether the safe-to-copy bit is set in the chunk type.
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*/
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default:
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if (SAFE_TO_COPY(type))
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{
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if (global->skip >= SKIP_UNUSED) /* as above */
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return 1;
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}
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else if (global->skip >= SKIP_UNSAFE)
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return 1;
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return 0;
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}
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}
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/* PER-FILE CONTROL STRUCTURE */
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struct chunk;
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struct IDAT;
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@ -2672,7 +2759,6 @@ process_chunk(struct file *file, png_uint_32 file_crc, png_uint_32 next_length,
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*/
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{
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const png_uint_32 type = file->type;
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int critical = CRITICAL(type);
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if (file->global->verbose > 1)
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{
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@ -2700,7 +2786,7 @@ process_chunk(struct file *file, png_uint_32 file_crc, png_uint_32 next_length,
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type_message(file, type, "bad CRC");
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/* This will cause an IEND with a bad CRC to stop */
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else if (critical)
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else if (CRITICAL(type))
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stop(file, READ_ERROR_CODE, "bad CRC in critical chunk");
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else
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@ -2716,32 +2802,8 @@ process_chunk(struct file *file, png_uint_32 file_crc, png_uint_32 next_length,
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* ancillary chunks (and not tRNS, which should probably have been a critical
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* chunk.)
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*/
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if (!critical)
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{
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unsigned int skip = file->global->skip;
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/* SKIP_BAD_CRC was handled above: */
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if (skip > SKIP_BAD_CRC) switch (type)
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{
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case png_tRNS: case png_sBIT: /* always handle this */
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break;
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case png_gAMA: case png_sRGB:
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if (skip >= SKIP_ALL)
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goto skip_chunk;
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break;
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case png_cHRM: case png_iCCP:
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if (skip >= SKIP_COLOR)
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goto skip_chunk;
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break;
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default:
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if (skip >= SKIP_NON_IMAGE)
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goto skip_chunk;
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break;
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}
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}
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if (skip_chunk_type(file->global, type))
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goto skip_chunk;
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/* The chunk may still be skipped if problems are detected in the LZ data,
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* however the LZ data check requires a chunk. Handle this by instantiating
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@ -2884,6 +2946,7 @@ sync_stream(struct file *file)
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/* Return to the start of the chunk data */
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file_setpos(file, &file->data_pos);
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file->read_count = 8;
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if (read_4(file, &file_crc) == 4) /* else completely truncated */
|
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{
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@ -3109,10 +3172,10 @@ read_callback(png_structp png_ptr, png_bytep buffer, size_t count)
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assert(file->read_count == 0);
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assert((file->status_code & TRUNCATED) == 0);
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|
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file->read_count = read_4(file, &file->length);
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(void)read_4(file, &file->length);
|
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|
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if (file->read_count == 4)
|
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file->read_count += read_4(file, &file->type);
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(void)read_4(file, &file->type);
|
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|
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if (file->read_count < 8)
|
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{
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@ -3595,22 +3658,40 @@ usage(const char *prog)
|
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" the file.",
|
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" --optimize (-o):",
|
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" Find the smallest deflate window size for the compressed data.",
|
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" --strip=[none|crc|unused|color|all]:",
|
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" none: Retain all chunks.",
|
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" --strip=[none|crc|unsafe|unused|transform|color|all]:",
|
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" none (default): Retain all chunks.",
|
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" crc: Remove chunks with a bad CRC.",
|
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" unused: Remove chunks not used by libpng.",
|
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" 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.",
|
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" 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 ommited the original chunk sizes will not be changed.",
|
||||
" 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",
|
||||
" 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).",
|
||||
@ -3698,7 +3779,7 @@ usage(const char *prog)
|
||||
" chunk SKP comp-level file-bits zlib-rc compressed message file",
|
||||
" chunk ??? comp-level file-bits ok-bits compressed uncompress file",
|
||||
0,
|
||||
" The varrious fields are",
|
||||
" 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.",
|
||||
@ -3710,9 +3791,9 @@ 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.",
|
||||
"$3 status: For 'ERR' the accumulate status code from 'EXIT CODES' above,",
|
||||
" this is printed as a 2 digit hexadecimal value",
|
||||
" 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",
|
||||
@ -3723,7 +3804,7 @@ usage(const char *prog)
|
||||
" 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",
|
||||
" 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",
|
||||
@ -3769,11 +3850,21 @@ 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;
|
||||
|
||||
@ -3792,8 +3883,14 @@ 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;
|
||||
|
||||
75
pngpriv.h
75
pngpriv.h
@ -670,37 +670,64 @@
|
||||
* architectures where (int) is only 16 bits.
|
||||
*/
|
||||
#define PNG_32b(b,s) ((png_uint_32)(b) << (s))
|
||||
#define PNG_CHUNK(b1,b2,b3,b4) \
|
||||
#define PNG_U32(b1,b2,b3,b4) \
|
||||
(PNG_32b(b1,24) | PNG_32b(b2,16) | PNG_32b(b3,8) | PNG_32b(b4,0))
|
||||
|
||||
#define png_IHDR PNG_CHUNK( 73, 72, 68, 82)
|
||||
#define png_IDAT PNG_CHUNK( 73, 68, 65, 84)
|
||||
#define png_IEND PNG_CHUNK( 73, 69, 78, 68)
|
||||
#define png_PLTE PNG_CHUNK( 80, 76, 84, 69)
|
||||
#define png_bKGD PNG_CHUNK( 98, 75, 71, 68)
|
||||
#define png_cHRM PNG_CHUNK( 99, 72, 82, 77)
|
||||
#define png_gAMA PNG_CHUNK(103, 65, 77, 65)
|
||||
#define png_hIST PNG_CHUNK(104, 73, 83, 84)
|
||||
#define png_iCCP PNG_CHUNK(105, 67, 67, 80)
|
||||
#define png_iTXt PNG_CHUNK(105, 84, 88, 116)
|
||||
#define png_oFFs PNG_CHUNK(111, 70, 70, 115)
|
||||
#define png_pCAL PNG_CHUNK(112, 67, 65, 76)
|
||||
#define png_sCAL PNG_CHUNK(115, 67, 65, 76)
|
||||
#define png_pHYs PNG_CHUNK(112, 72, 89, 115)
|
||||
#define png_sBIT PNG_CHUNK(115, 66, 73, 84)
|
||||
#define png_sPLT PNG_CHUNK(115, 80, 76, 84)
|
||||
#define png_sRGB PNG_CHUNK(115, 82, 71, 66)
|
||||
#define png_sTER PNG_CHUNK(115, 84, 69, 82)
|
||||
#define png_tEXt PNG_CHUNK(116, 69, 88, 116)
|
||||
#define png_tIME PNG_CHUNK(116, 73, 77, 69)
|
||||
#define png_tRNS PNG_CHUNK(116, 82, 78, 83)
|
||||
#define png_zTXt PNG_CHUNK(122, 84, 88, 116)
|
||||
/* Constants for known chunk types.
|
||||
*
|
||||
* MAINTAINERS: If you need to add a chunk, define the name here.
|
||||
* For historical reasons these constants have the form png_<name>; i.e.
|
||||
* the prefix is lower case. Please use decimal values as the parameters to
|
||||
* match the ISO PNG specification and to avoid relying on the C locale
|
||||
* interpretation of character values. Please keep the list sorted.
|
||||
*
|
||||
* Notice that PNG_U32 is used to define a 32-bit value for the 4 byte chunk
|
||||
* type. In fact the specification does not express chunk types this way,
|
||||
* however using a 32-bit value means that the chunk type can be read from the
|
||||
* stream using exactly the same code as used for a 32-bit unsigned value and
|
||||
* can be examined far more efficiently (using one arithmetic compare).
|
||||
*
|
||||
* Prior to 1.5.6 the chunk type constants were expressed as C strings. The
|
||||
* libpng API still uses strings for 'unknown' chunks and a macro,
|
||||
* PNG_STRING_FROM_CHUNK, allows a string to be generated if required. Notice
|
||||
* that for portable code numeric values must still be used; the string "IHDR"
|
||||
* is not portable and neither is PNG_U32('I', 'H', 'D', 'R').
|
||||
*
|
||||
* In 1.7.0 the definitions will be made public in png.h to avoid having to
|
||||
* duplicate the same definitions in application code.
|
||||
*/
|
||||
#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)
|
||||
|
||||
/* The following will work on (signed char*) strings, whereas the get_uint_32
|
||||
* macro will fail on top-bit-set values because of the sign extension.
|
||||
*/
|
||||
#define PNG_CHUNK_FROM_STRING(s)\
|
||||
PNG_CHUNK(0xff&(s)[0], 0xff&(s)[1], 0xff&(s)[2], 0xff&(s)[3])
|
||||
PNG_U32(0xff&(s)[0], 0xff&(s)[1], 0xff&(s)[2], 0xff&(s)[3])
|
||||
|
||||
/* This uses (char), not (png_byte) to avoid warnings on systems where (char) is
|
||||
* signed and the argument is a (char[]) This macro will fail miserably on
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user