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[libpng17] Revised pngfix.c to use PNG_U32() instead of PNG_CHUNK()

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This commit is contained in:
Glenn Randers-Pehrson 2013-07-02 09:52:09 -05:00
parent 7905286ffa
commit 5aa2ca454d
3 changed files with 12 additions and 38 deletions
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5
ANNOUNCE
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@ -1,5 +1,5 @@
Libpng 1.7.0beta16 - July 1, 2013
Libpng 1.7.0beta16 - July 2, 2013
This is not intended to be a public release. It will be replaced
within a few weeks by a public version or by another test version.
@ -331,12 +331,13 @@ Version 1.7.0beta14 [June 8, 2013]
Version 1.7.0beta15 [June 18, 2013]
Revised libpng.3 so that "doclifter" can process it.
Version 1.7.0beta16 [July 1, 2013]
Version 1.7.0beta16 [July 2, 2013]
Revised example.c to illustrate use of PNG_DEFAULT_sRGB and PNG_GAMMA_MAC_18
as parameters for png_set_gamma(). These have been available since
libpng-1.5.4.
Renamed contrib/tools/png-fix-too-far-back.c to pngfix.c and revised it
to check all compressed chunks known to libpng.
Updated documentation to show default behavior of benign errors correctly.
Send comments/corrections/commendations to png-mng-implement at lists.sf.net
(subscription required; visit

3
CHANGES
View File

@ -4619,12 +4619,13 @@ Version 1.7.0beta14 [June 8, 2013]
Version 1.7.0beta15 [June 18, 2013]
Revised libpng.3 so that "doclifter" can process it.
Version 1.7.0beta16 [July 1, 2013]
Version 1.7.0beta16 [July 2, 2013]
Revised example.c to illustrate use of PNG_DEFAULT_sRGB and PNG_GAMMA_MAC_18
as parameters for png_set_gamma(). These have been available since
libpng-1.5.4.
Renamed contrib/tools/png-fix-too-far-back.c to pngfix.c and revised it
to check all compressed chunks known to libpng.
Updated documentation to show default behavior of benign errors correctly.
Send comments/corrections/commendations to png-mng-implement at lists.sf.net
(subscription required; visit

42
contrib/tools/pngfix.c
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@ -2,7 +2,7 @@
*
* Copyright (c) 2013 John Cunningham Bowler
*
* Last changed in libpng 1.6.3 [(PENDING RELEASE)]
* Last changed in libpng 1.7.0 [(PENDING RELEASE)]
*
* This code is released under the libpng license.
* For conditions of distribution and use, see the disclaimer
@ -73,40 +73,12 @@
# define png_aligncastconst(type, value) ((const void*)(value))
#endif /* __cplusplus */
/* Chunk tags (copied from pngpriv.h) */
#define PNG_32b(b,s) ((png_uint_32)(b) << (s))
#define PNG_CHUNK(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)
/* The 8 byte signature as a pair of 32 bit quantities */
#define sig1 PNG_CHUNK(137, 80, 78, 71)
#define sig2 PNG_CHUNK( 13, 10, 26, 10)
#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_CHUNK(32,0,0,0)) == 0)
#define CRITICAL(chunk) (((chunk) & PNG_U32(32,0,0,0)) == 0)
/********************************* UTILITIES **********************************/
/* UNREACHED is a value to cause an assert to fail. Because of the way the
@ -540,19 +512,19 @@ chunk_type_valid(png_uint_32 c)
* 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_CHUNK(32,32,0,32);
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_CHUNK(65,65,65,65);
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_CHUNK(25,25,25,26);
c -= PNG_U32(25,25,25,26);
t |= ~c;
return (t & 0xe0e0e0e0) == 0;