forked from hrydgard/ppsspp
-
Notifications
You must be signed in to change notification settings - Fork 0
/
png.h
4252 lines (3876 loc) · 191 KB
/
png.h
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/* png.h - header file for PNG reference library
*
* libpng version 1.7.0beta90, August 28, 2017
*
* Copyright (c) 1998-2002,2004,2006-2017 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
*
* This code is released under the libpng license (See LICENSE, below)
*
* Authors and maintainers:
* libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
* libpng versions 0.89, June 1996, through 0.96, May 1997: Andreas Dilger
* libpng versions 0.97, January 1998, through 1.7.0beta90, August 28, 2017:
* Glenn Randers-Pehrson.
* See also "Contributing Authors", below.
*/
/*
* COPYRIGHT NOTICE, DISCLAIMER, and LICENSE:
*
* If you modify libpng you may insert additional notices immediately following
* this sentence.
*
* This code is released under the libpng license.
*
* libpng versions 1.0.7, July 1, 2000 through 1.7.0beta90, August 28, 2017 are
* Copyright (c) 2000-2002, 2004, 2006-2017 Glenn Randers-Pehrson, are
* derived from libpng-1.0.6, and are distributed according to the same
* disclaimer and license as libpng-1.0.6 with the following individuals
* added to the list of Contributing Authors:
*
* Simon-Pierre Cadieux
* Eric S. Raymond
* Mans Rullgard
* Cosmin Truta
* Gilles Vollant
* James Yu
*
* and with the following additions to the disclaimer:
*
* There is no warranty against interference with your enjoyment of the
* library or against infringement. There is no warranty that our
* efforts or the library will fulfill any of your particular purposes
* or needs. This library is provided with all faults, and the entire
* risk of satisfactory quality, performance, accuracy, and effort is with
* the user.
*
* Some files in the "contrib" directory and some configure-generated
* files that are distributed with libpng have other copyright owners and
* are released under other open source licenses.
*
* libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
* Copyright (c) 1998-2000 Glenn Randers-Pehrson, are derived from
* libpng-0.96, and are distributed according to the same disclaimer and
* license as libpng-0.96, with the following individuals added to the list
* of Contributing Authors:
*
* Tom Lane
* Glenn Randers-Pehrson
* Willem van Schaik
*
* libpng versions 0.89, June 1996, through 0.96, May 1997, are
* Copyright (c) 1996-1997 Andreas Dilger, are derived from libpng-0.88,
* and are distributed according to the same disclaimer and license as
* libpng-0.88, with the following individuals added to the list of
* Contributing Authors:
*
* John Bowler
* Kevin Bracey
* Sam Bushell
* Magnus Holmgren
* Greg Roelofs
* Tom Tanner
*
* Some files in the "scripts" directory have other copyright owners
* but are released under this license.
*
* libpng versions 0.5, May 1995, through 0.88, January 1996, are
* Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
*
* For the purposes of this copyright and license, "Contributing Authors"
* is defined as the following set of individuals:
*
* Andreas Dilger
* Dave Martindale
* Guy Eric Schalnat
* Paul Schmidt
* Tim Wegner
*
* The PNG Reference Library is supplied "AS IS". The Contributing Authors
* and Group 42, Inc. disclaim all warranties, expressed or implied,
* including, without limitation, the warranties of merchantability and of
* fitness for any purpose. The Contributing Authors and Group 42, Inc.
* assume no liability for direct, indirect, incidental, special, exemplary,
* or consequential damages, which may result from the use of the PNG
* Reference Library, even if advised of the possibility of such damage.
*
* Permission is hereby granted to use, copy, modify, and distribute this
* source code, or portions hereof, for any purpose, without fee, subject
* to the following restrictions:
*
* 1. The origin of this source code must not be misrepresented.
*
* 2. Altered versions must be plainly marked as such and must not
* be misrepresented as being the original source.
*
* 3. This Copyright notice may not be removed or altered from any
* source or altered source distribution.
*
* The Contributing Authors and Group 42, Inc. specifically permit, without
* fee, and encourage the use of this source code as a component to
* supporting the PNG file format in commercial products. If you use this
* source code in a product, acknowledgment is not required but would be
* appreciated.
*
* END OF COPYRIGHT NOTICE, DISCLAIMER, and LICENSE.
*
* TRADEMARK:
*
* The name "libpng" has not been registered by the Copyright owner
* as a trademark in any jurisdiction. However, because libpng has
* been distributed and maintained world-wide, continually since 1995,
* the Copyright owner claims "common-law trademark protection" in any
* jurisdiction where common-law trademark is recognized.
*
* OSI CERTIFICATION:
*
* Libpng is OSI Certified Open Source Software. OSI Certified Open Source is
* a certification mark of the Open Source Initiative. OSI has not addressed
* the additional disclaimers inserted at version 1.0.7.
*
* EXPORT CONTROL:
*
* The Copyright owner believes that the Export Control Classification
* Number (ECCN) for libpng is EAR99, which means not subject to export
* controls or International Traffic in Arms Regulations (ITAR) because
* it is open source, publicly available software, that does not contain
* any encryption software. See the EAR, paragraphs 734.3(b)(3) and
* 734.7(b).
*/
/*
* A "png_get_copyright" function is available, for convenient use in "about"
* boxes and the like:
*
* printf("%s", png_get_copyright(NULL));
*
* Also, the PNG logo (in PNG format, of course) is supplied in the
* files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).
*/
/*
* The contributing authors would like to thank all those who helped
* with testing, bug fixes, and patience. This wouldn't have been
* possible without all of you.
*
* Thanks to Frank J. T. Wojcik for helping with the documentation.
*/
/* Note about libpng version numbers:
*
* Due to various miscommunications, unforeseen code incompatibilities
* and occasional factors outside the authors' control, version numbering
* on the library has not always been consistent and straightforward.
* The following table summarizes matters since version 0.89c, which was
* the first widely used release:
*
* source png.h png.h shared-lib
* version string int version
* ------- ------ ----- ----------
* 0.89c "1.0 beta 3" 0.89 89 1.0.89
* 0.90 "1.0 beta 4" 0.90 90 0.90 [should have been 2.0.90]
* 0.95 "1.0 beta 5" 0.95 95 0.95 [should have been 2.0.95]
* 0.96 "1.0 beta 6" 0.96 96 0.96 [should have been 2.0.96]
* 0.97b "1.00.97 beta 7" 1.00.97 97 1.0.1 [should have been 2.0.97]
* 0.97c 0.97 97 2.0.97
* 0.98 0.98 98 2.0.98
* 0.99 0.99 98 2.0.99
* 0.99a-m 0.99 99 2.0.99
* 1.00 1.00 100 2.1.0 [100 should be 10000]
* 1.0.0 (from here on, the 100 2.1.0 [100 should be 10000]
* 1.0.1 png.h string is 10001 2.1.0
* 1.0.1a-e identical to the 10002 from here on, the shared library
* 1.0.2 source version) 10002 is 2.V where V is the source code
* 1.0.2a-b 10003 version, except as noted.
* 1.0.3 10003
* 1.0.3a-d 10004
* 1.0.4 10004
* 1.0.4a-f 10005
* 1.0.5 (+ 2 patches) 10005
* 1.0.5a-d 10006
* 1.0.5e-r 10100 (not source compatible)
* 1.0.5s-v 10006 (not binary compatible)
* 1.0.6 (+ 3 patches) 10006 (still binary incompatible)
* 1.0.6d-f 10007 (still binary incompatible)
* 1.0.6g 10007
* 1.0.6h 10007 10.6h (testing xy.z so-numbering)
* 1.0.6i 10007 10.6i
* 1.0.6j 10007 2.1.0.6j (incompatible with 1.0.0)
* 1.0.7beta11-14 DLLNUM 10007 2.1.0.7beta11-14 (binary compatible)
* 1.0.7beta15-18 1 10007 2.1.0.7beta15-18 (binary compatible)
* 1.0.7rc1-2 1 10007 2.1.0.7rc1-2 (binary compatible)
* 1.0.7 1 10007 (still compatible)
* ...
* 1.0.19 10 10019 10.so.0.19[.0]
* ...
* 1.2.56 13 10253 12.so.0.53[.0]
* ...
* 1.5.27 15 10523 15.so.15.23[.0]
* ...
* 1.6.22 16 10622 16.so.16.22[.0]
* ...
* 1.7.0alpha01-10 17 10700 17.so.17.0[.0]
* 1.7.0beta01-84 17 10700 17.so.17.0[.0]
*
* Henceforth the source version will match the shared-library major
* and minor numbers; the shared-library major version number will be
* used for changes in backward compatibility, as it is intended. The
* PNG_LIBPNG_VER macro, which is not used within libpng but is available
* for applications, is an unsigned integer of the form xyyzz corresponding
* to the source version x.y.z (leading zeros in y and z). Beta versions
* were given the previous public release number plus a letter, until
* version 1.0.6j; from then on they were given the upcoming public
* release number plus "betaNN" or "rcNN".
*
* Binary incompatibility exists only when applications make direct access
* to the info_ptr or png_ptr members through png.h, and the compiled
* application is loaded with a different version of the library.
*
* DLLNUM will change each time there are forward or backward changes
* in binary compatibility (e.g., when a new feature is added).
*
* See libpng.txt or libpng.3 for more information. The PNG specification
* is available as a W3C Recommendation and as an ISO Specification,
* <https://www.w3.org/TR/2003/REC-PNG-20031110/
*/
/*
* Y2K compliance in libpng:
* =========================
*
* August 28, 2017
*
* Since the PNG Development group is an ad-hoc body, we can't make
* an official declaration.
*
* This is your unofficial assurance that libpng from version 0.71 and
* upward through 1.7.0beta90 are Y2K compliant. It is my belief that
* earlier versions were also Y2K compliant.
*
* Libpng only has two year fields. One is a 2-byte unsigned integer
* that will hold years up to 65535. The other, which is deprecated,
* holds the date in text format, and will hold years up to 9999.
*
* The integer is
* "png_uint_16 year" in png_time_struct.
*
* The string is
* "char time_buffer[29]" in png_struct. This is no longer used
* in libpng-1.6.x and will be removed from libpng-1.7.0.
*
* There are seven time-related functions:
* png.c: png_convert_to_rfc_1123_buffer() in png.c
* (formerly png_convert_to_rfc_1123() prior to libpng-1.5.x and
* png_convert_to_rfc_1152() in error prior to libpng-0.98)
* png_convert_from_struct_tm() in pngwrite.c, called in pngwrite.c
* png_convert_from_time_t() in pngwrite.c
* png_get_tIME() in pngget.c
* png_handle_tIME() in pngrutil.c, called in pngread.c
* png_set_tIME() in pngset.c
* png_write_tIME() in pngwutil.c, called in pngwrite.c
*
* All handle dates properly in a Y2K environment. The
* png_convert_from_time_t() function calls gmtime() to convert from system
* clock time, which returns (year - 1900), which we properly convert to
* the full 4-digit year. There is a possibility that libpng applications
* are not passing 4-digit years into the png_convert_to_rfc_1123_buffer()
* function, or that they are incorrectly passing only a 2-digit year
* instead of "year - 1900" into the png_convert_from_struct_tm() function,
* but this is not under our control. The libpng documentation has always
* stated that it works with 4-digit years, and the APIs have been
* documented as such.
*
* The tIME chunk itself is also Y2K compliant. It uses a 2-byte unsigned
* integer to hold the year, and can hold years as large as 65535.
*
* zlib, upon which libpng depends, is also Y2K compliant. It contains
* no date-related code.
*
* Glenn Randers-Pehrson
* libpng maintainer
* PNG Development Group
*/
#ifndef PNG_H
#define PNG_H
/* This is not the place to learn how to use libpng. The file libpng-manual.txt
* describes how to use libpng, and the file example.c summarizes it
* with some code on which to build. This file is useful for looking
* at the actual function definitions and structure components. If that
* file has been stripped from your copy of libpng, you can find it at
* <http://www.libpng.org/pub/png/libpng-manual.txt>
*
* If you just need to read a PNG file and don't want to read the documentation
* skip to the end of this file and read the section entitled 'simplified API'.
*/
/* Version information for png.h - this should match the version in png.c */
#define PNG_LIBPNG_VER_STRING "1.7.0beta90"
#define PNG_HEADER_VERSION_STRING " libpng version 1.7.0beta90 - August 28, 2017\n"
#define PNG_LIBPNG_VER_SONUM 17
#define PNG_LIBPNG_VER_DLLNUM 17
/* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
#define PNG_LIBPNG_VER_MAJOR 1
#define PNG_LIBPNG_VER_MINOR 7
#define PNG_LIBPNG_VER_RELEASE 0
/* This should match the numeric part of the final component of
* PNG_LIBPNG_VER_STRING, omitting any leading zero:
*/
#define PNG_LIBPNG_VER_BUILD 90
/* Release Status */
#define PNG_LIBPNG_BUILD_ALPHA 1
#define PNG_LIBPNG_BUILD_BETA 2
#define PNG_LIBPNG_BUILD_RC 3
#define PNG_LIBPNG_BUILD_STABLE 4
#define PNG_LIBPNG_BUILD_RELEASE_STATUS_MASK 7
/* Release-Specific Flags */
#define PNG_LIBPNG_BUILD_PATCH 8 /* Can be OR'ed with
PNG_LIBPNG_BUILD_STABLE only */
#define PNG_LIBPNG_BUILD_PRIVATE 16 /* Cannot be OR'ed with
PNG_LIBPNG_BUILD_SPECIAL */
#define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with
PNG_LIBPNG_BUILD_PRIVATE */
#define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_BETA
/* Careful here. At one time, Guy wanted to use 082, but that would be octal.
* We must not include leading zeros.
* Versions 0.7 through 1.0.0 were in the range 0 to 100 here (only
* version 1.0.0 was mis-numbered 100 instead of 10000). From
* version 1.0.1 it's xxyyzz, where x=major, y=minor, z=release
*/
#define PNG_LIBPNG_VER 10700 /* 1.7.0 */
/* Library configuration: these options cannot be changed after
* the library has been built.
*/
#ifndef PNGLCONF_H
/* If pnglibconf.h is missing, you can
* copy scripts/pnglibconf.h.prebuilt to pnglibconf.h
*/
# include "pnglibconf.h"
#endif
#ifndef PNG_VERSION_INFO_ONLY
/* Machine specific configuration. */
# include "pngconf.h"
#endif
/*
* Added at libpng-1.2.8
*
* Ref MSDN: Private as priority over Special
* VS_FF_PRIVATEBUILD File *was not* built using standard release
* procedures. If this value is given, the StringFileInfo block must
* contain a PrivateBuild string.
*
* VS_FF_SPECIALBUILD File *was* built by the original company using
* standard release procedures but is a variation of the standard
* file of the same version number. If this value is given, the
* StringFileInfo block must contain a SpecialBuild string.
*/
#ifdef PNG_USER_PRIVATEBUILD /* From pnglibconf.h */
# define PNG_LIBPNG_BUILD_TYPE \
(PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_PRIVATE)
#else
# ifdef PNG_LIBPNG_SPECIALBUILD
# define PNG_LIBPNG_BUILD_TYPE \
(PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_SPECIAL)
# else
# define PNG_LIBPNG_BUILD_TYPE (PNG_LIBPNG_BUILD_BASE_TYPE)
# endif
#endif
#ifndef PNG_VERSION_INFO_ONLY
/* Version information for C files, stored in png.c. This had better match
* the version above.
*/
#define png_libpng_ver png_get_header_ver(NULL)
/* This file is arranged in several sections:
*
* 1. ISO-PNG constants and definitions; values defined by PNG and not specific
* to the libpng API.
* 2. Any configuration options that can be specified by for the application
* code when it is built. (Build time configuration is in pnglibconf.h)
* 3. Type definitions (base types are defined in pngconf.h), structure
* definitions.
* 4. Exported library functions.
* 5. Simplified API.
* 6. Implementation options
*
* The library source code has additional files (principally pngpriv.h) that
* allow configuration of the library.
*/
/* Section 1: ISO PNG constants and macros. */
/* ISO-PNG defines byte encodings for 16 and 32-bit unsigned values and 32-bit
* signed values. The macros PNG_U16, PNG_U32 and PNG_S32 return values of type
* (png_uint_16), (png_uint_32) and (png_int_32) which are target machine
* specific representations of these values, using the types defined in
* pngconf.h. The macros take two or four byte values in the order in which
* they would occur in a PNG stream.
*
* These macros must return compile time constants if passed constant values -
* machine specific implementations are not permitted. These macros are used by
* default in the API functions/macros png_get_uint_16, png_get_uint_32,
* png_get_uint_31 and png_get_int_32 declared below: these functions or macros
* are the correct places for machine specific implementations (such as hardware
* specific instructions.)
*
* The macros defined here are generic and intended to give maximum flexibility
* in implementation to the compiler; only PNG_S32 contains a sequence point,
* there are no side effects and the expressions used permit the maximum
* parallelization (relevant because the four bytes may be loaded in parallel.)
*/
#define PNG_u2(b1, b2) (((unsigned int)(b1) << 8) + (b2))
#define PNG_U16(b1, b2) ((png_uint_16)/*SAFE*/PNG_u2(b1, b2))
#define PNG_U32(b1, b2, b3, b4)\
(((png_uint_32)/*SAFE*/PNG_u2(b1, b2) << 16) + PNG_u2(b3, b4))
/* ISO-PNG states that signed 32-bit values are stored in two's complement
* format. There is no guarantee that (png_int_32) is exactly 32 bits, so the
* following macro tests for a negative number and generates the machine format
* directly by portable arithmetic operations. The cost is that the argument
* 'b1' is evaluated twice.
*
* NOTE: the 0x7fffffffU BIC is there to ensure that potential overflow in the
* cast does not occur. This fixes the case where 1's complement machines could
* be forced into an overflow by an invalid value in the stream and, therefore,
* potentially raise an arithmetic exception; the invalid value is converted to
* 0 and any resultant problems will be caught later in the libpng checking.
*/
#define PNG_S32(b1, b2, b3, b4) ((b1) & 0x80\
? -(png_int_32)(((PNG_U32(b1, b2, b3, b4)^0xffffffffU)+1U)&0x7fffffffU)\
: (png_int_32)PNG_U32(b1, b2, b3, b4))
/* 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 were made public in png.h to avoid having to
* duplicate the same definitions in application code.
*
* SOURCE: http://www.libpng.org/pub/png/spec/register/
* "Register of PNG Public Chunks and Keywords, version 1.4.6"
* "Extensions to the PNG Specification, version 1.4.0"
*/
#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_dSIG PNG_U32(100, 83, 73, 71) /* separate spec */
#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 PNG_U32 macro
* used directory would fail on top-bit-set values because of the sign
* extension.
*/
#define PNG_CHUNK_FROM_STRING(s)\
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
* systems where (char) is more than 8 bits.
*/
#define PNG_STRING_FROM_CHUNK(s,c)\
(void)(((char*)(s))[0]=(char)(((c)>>24) & 0xff), \
((char*)(s))[1]=(char)(((c)>>16) & 0xff),\
((char*)(s))[2]=(char)(((c)>>8) & 0xff), \
((char*)(s))[3]=(char)((c & 0xff)))
/* Do the same but terminate with a null character. */
#define PNG_CSTRING_FROM_CHUNK(s,c)\
(void)(PNG_STRING_FROM_CHUNK(s,c), ((char*)(s))[4] = 0)
/* Test on flag values as defined in the spec (section 5.4): */
#define PNG_CHUNK_ANCILLARY(c) (1 & ((c) >> 29))
#define PNG_CHUNK_CRITICAL(c) (!PNG_CHUNK_ANCILLARY(c))
#define PNG_CHUNK_PRIVATE(c) (1 & ((c) >> 21))
#define PNG_CHUNK_RESERVED(c) (1 & ((c) >> 13))
#define PNG_CHUNK_SAFE_TO_COPY(c) (1 & ((c) >> 5))
/* Section 2: run time configuration
* See pnglibconf.h for build time configuration
*
* Run time configuration allows the application to choose between
* implementations of certain arithmetic APIs. The default is set
* at build time and recorded in pnglibconf.h, but it is safe to
* override these (and only these) settings. Note that this won't
* change what the library does, only application code, and the
* settings can (and probably should) be made on a per-file basis
* by setting the #defines before including png.h
*
* Use macros to read integers from PNG data or use the exported
* functions?
* PNG_USE_READ_MACROS: use the macros (see below) Note that
* the macros evaluate their argument multiple times.
* PNG_NO_USE_READ_MACROS: call the relevant library function.
*
* Use the alternative algorithm for compositing alpha samples that
* does not use division?
* PNG_READ_COMPOSITE_NODIV_SUPPORTED: use the 'no division'
* algorithm.
* PNG_NO_READ_COMPOSITE_NODIV: use the 'division' algorithm.
*
* How to handle benign errors if PNG_ALLOW_BENIGN_ERRORS is
* false?
* PNG_ALLOW_BENIGN_ERRORS: map calls to the benign error
* APIs to png_warning.
* Otherwise the calls are mapped to png_error.
*/
/* Inhibit C++ name-mangling for libpng functions but not for system calls. */
#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */
/* Section 3: type definitions, including structures and compile time
* constants.
* See pngconf.h for base types that vary by machine/system
*/
/* This triggers a compiler error in png.c, if png.c and png.h
* do not agree upon the version number.
*/
typedef char* png_libpng_version_1_7_0beta90;
/* Basic control structions. Read libpng-manual.txt or libpng.3 for more info.
*
* png_struct is the cache of information used while reading or writing a single
* PNG file. One of these is always required, although the simplified API
* (below) hides the creation and destruction of it.
*/
typedef struct png_struct_def png_struct;
typedef const png_struct * png_const_structp;
typedef png_struct * png_structp;
typedef png_struct * * png_structpp;
/* png_info contains information read from or to be written to a PNG file. One
* or more of these must exist while reading or creating a PNG file. The
* information is not used by libpng during read but is used to control what
* gets written when a PNG file is created. "png_get_" function calls read
* information during read and "png_set_" functions calls write information
* when creating a PNG.
* been moved into a separate header file that is not accessible to
* applications. Read libpng-manual.txt or libpng.3 for more info.
*/
typedef struct png_info_def png_info;
typedef png_info * png_infop;
typedef const png_info * png_const_infop;
typedef png_info * * png_infopp;
/* Types with names ending 'p' are pointer types. The corresponding types with
* names ending 'rp' are identical pointer types except that the pointer is
* marked 'restrict', which means that it is the only pointer to the object
* passed to the function. Applications should not use the 'restrict' types;
* it is always valid to pass 'p' to a pointer with a function argument of the
* corresponding 'rp' type. Different compilers have different rules with
* regard to type matching in the presence of 'restrict'. For backward
* compatibility libpng callbacks never have 'restrict' in their parameters and,
* consequentially, writing portable application code is extremely difficult if
* an attempt is made to use 'restrict'.
*/
typedef png_struct * PNG_RESTRICT png_structrp;
typedef const png_struct * PNG_RESTRICT png_const_structrp;
typedef png_info * PNG_RESTRICT png_inforp;
typedef const png_info * PNG_RESTRICT png_const_inforp;
/* Three color definitions. The order of the red, green, and blue, (and the
* exact size) is not important, although the size of the fields need to
* be png_byte or png_uint_16 (as defined below).
*/
typedef struct png_color_struct
{
png_byte red;
png_byte green;
png_byte blue;
} png_color;
typedef png_color * png_colorp;
typedef const png_color * png_const_colorp;
typedef png_color * * png_colorpp;
typedef struct png_color_16_struct
{
png_byte index; /* used for palette files */
png_uint_16 red; /* for use in red green blue files */
png_uint_16 green;
png_uint_16 blue;
png_uint_16 gray; /* for use in grayscale files */
} png_color_16;
typedef png_color_16 * png_color_16p;
typedef const png_color_16 * png_const_color_16p;
typedef png_color_16 * * png_color_16pp;
typedef struct png_color_8_struct
{
png_byte red; /* for use in red green blue files */
png_byte green;
png_byte blue;
png_byte gray; /* for use in grayscale files */
png_byte alpha; /* for alpha channel files */
} png_color_8;
typedef png_color_8 * png_color_8p;
typedef const png_color_8 * png_const_color_8p;
typedef png_color_8 * * png_color_8pp;
/*
* The following two structures are used for the in-core representation
* of sPLT chunks.
*/
typedef struct png_sPLT_entry_struct
{
png_uint_16 red;
png_uint_16 green;
png_uint_16 blue;
png_uint_16 alpha;
png_uint_16 frequency;
} png_sPLT_entry;
typedef png_sPLT_entry * png_sPLT_entryp;
typedef const png_sPLT_entry * png_const_sPLT_entryp;
typedef png_sPLT_entry * * png_sPLT_entrypp;
/* When the depth of the sPLT palette is 8 bits, the color and alpha samples
* occupy the LSB of their respective members, and the MSB of each member
* is zero-filled. The frequency member always occupies the full 16 bits.
*/
typedef struct png_sPLT_struct
{
png_charp name; /* palette name */
png_byte depth; /* depth of palette samples */
png_sPLT_entryp entries; /* palette entries */
png_int_32 nentries; /* number of palette entries */
} png_sPLT_t;
typedef png_sPLT_t * png_sPLT_tp;
typedef const png_sPLT_t * png_const_sPLT_tp;
typedef png_sPLT_t * * png_sPLT_tpp;
#ifdef PNG_TEXT_SUPPORTED
/* png_text holds the contents of a text/ztxt/itxt chunk in a PNG file,
* and whether that contents is compressed or not. The "key" field
* points to a regular zero-terminated C string. The "text" fields can be a
* regular C string, an empty string, or a NULL pointer.
* However, the structure returned by png_get_text() will always contain
* the "text" field as a regular zero-terminated C string (possibly
* empty), never a NULL pointer, so it can be safely used in printf() and
* other string-handling functions. Note that the "itxt_length", "lang", and
* "lang_key" members of the structure only exist when the library is built
* with iTXt chunk support. Prior to libpng-1.4.0 the library was built by
* default without iTXt support. Also note that when iTXt *is* supported,
* the "lang" and "lang_key" fields contain NULL pointers when the
* "compression" field contains * PNG_TEXT_COMPRESSION_NONE or
* PNG_TEXT_COMPRESSION_zTXt. Note that the "compression value" is not the
* same as what appears in the PNG tEXt/zTXt/iTXt chunk's "compression flag"
* which is always 0 or 1, or its "compression method" which is always 0.
*
* The location field (added in libpng 1.7.0) records where the text chunk was
* found when png_get_text is used. When png_set_text is used the field in the
* structure passed in is ignored and, instead, the field is set to the current
* write position.
*
* Prior to 1.7.0 the write behavior was the same; the text fields were written
* (once) at the next write_info call, however the read mechanism did not record
* the chunk location so if an info_struct from read was passed to the write
* APIs the text chunks would all be written at the start (before PLTE).
*/
typedef struct png_text_struct
{
int compression; /* compression value:
-1: tEXt, none
0: zTXt, deflate
1: iTXt, none
2: iTXt, deflate */
png_byte location; /* 1: PNG_HAVE_IHDR
2: PNG_HAVE_PLTE
8: PNG_AFTER_IDAT */
png_charp key; /* keyword, 1-79 character description of "text" */
png_charp text; /* comment, may be an empty string (ie "")
or a NULL pointer */
size_t text_length; /* length of the text string */
size_t itxt_length; /* length of the itxt string */
png_charp lang; /* language code, 0-79 characters
or a NULL pointer */
png_charp lang_key; /* keyword translated UTF-8 string, 0 or more
chars or a NULL pointer */
} png_text;
typedef png_text * png_textp;
typedef const png_text * png_const_textp;
typedef png_text * * png_textpp;
#endif
/* Supported compression types for text in PNG files (tEXt, and zTXt).
* The values of the PNG_TEXT_COMPRESSION_ defines should NOT be changed. */
#ifdef PNG_OLD_COMPRESSION_CODES_SUPPORTED
/* These values were used to prevent double write of text chunks in versions
* prior to 1.7.0. They are never set now; if you need them #define the
* _SUPPORTED macro.
*/
#define PNG_TEXT_COMPRESSION_NONE_WR -3
#define PNG_TEXT_COMPRESSION_zTXt_WR -2
#endif /* OLD_COMPRESSION_CODES */
#define PNG_TEXT_COMPRESSION_NONE -1
#define PNG_TEXT_COMPRESSION_zTXt 0
#define PNG_ITXT_COMPRESSION_NONE 1
#define PNG_ITXT_COMPRESSION_zTXt 2
#define PNG_TEXT_COMPRESSION_LAST 3 /* Not a valid value */
/* png_time is a way to hold the time in an machine independent way.
* Two conversions are provided, both from time_t and struct tm. There
* is no portable way to convert to either of these structures, as far
* as I know. If you know of a portable way, send it to me. As a side
* note - PNG has always been Year 2000 compliant!
*/
typedef struct png_time_struct
{
png_uint_16 year; /* full year, as in, 1995 */
png_byte month; /* month of year, 1 - 12 */
png_byte day; /* day of month, 1 - 31 */
png_byte hour; /* hour of day, 0 - 23 */
png_byte minute; /* minute of hour, 0 - 59 */
png_byte second; /* second of minute, 0 - 60 (for leap seconds) */
} png_time;
typedef png_time * png_timep;
typedef const png_time * png_const_timep;
typedef png_time * * png_timepp;
#if defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) ||\
defined(PNG_USER_CHUNKS_SUPPORTED)
/* png_unknown_chunk is a structure to hold queued chunks for which there is
* no specific support. The idea is that we can use this to queue
* up private chunks for output even though the library doesn't actually
* know about their semantics.
*
* The data in the structure is set by libpng on read and used on write.
*/
typedef struct png_unknown_chunk_t
{
png_byte *data; /* Data, should not be modified on read! */
png_uint_32 size; /* Size of data, must not exceed 0x7fffffff.
* API CHANGE 1.7.0: changed from 'size_t'
*/
png_byte name[5]; /* Textual chunk name with '\0' terminator */
/* On write 'location' must be set using the flag values listed below.
* Notice that on read it is set by libpng however the values stored have
* more bits set than are listed below. Always treat the value as a
* bitmask. On write set only one bit - setting multiple bits may cause the
* chunk to be written in multiple places.
*/
png_byte location; /* mode of operation at read time */
}
png_unknown_chunk;
typedef png_unknown_chunk * png_unknown_chunkp;
typedef const png_unknown_chunk * png_const_unknown_chunkp;
typedef png_unknown_chunk * * png_unknown_chunkpp;
#endif
/* Flag values for the chunk location byte. */
#define PNG_HAVE_IHDR 0x01U
#define PNG_HAVE_PLTE 0x02U
#define PNG_AFTER_IDAT 0x08U
/* Maximum positive integer used in PNG is (2^31)-1 */
#define PNG_UINT_31_MAX ((png_uint_32)0x7fffffffL)
#define PNG_UINT_32_MAX ((png_uint_32)(-1))
#define PNG_SIZE_MAX ((size_t)(-1))
/* These are constants for fixed point values encoded in the
* PNG specification manner (x100000)
*/
#define PNG_FP_1 100000
#define PNG_FP_HALF 50000
#define PNG_FP_MAX ((png_fixed_point)0x7fffffffL)
#define PNG_FP_MIN (-PNG_FP_MAX)
/* These describe the color_type field in png_info. */
/* color type masks */
#define PNG_COLOR_MASK_PALETTE 1U
#define PNG_COLOR_MASK_COLOR 2U
#define PNG_COLOR_MASK_ALPHA 4U
/* color types. Note that not all combinations are legal */
#define PNG_COLOR_TYPE_GRAY 0U
#define PNG_COLOR_TYPE_PALETTE (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)
#define PNG_COLOR_TYPE_RGB (PNG_COLOR_MASK_COLOR)
#define PNG_COLOR_TYPE_RGB_ALPHA (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA)
#define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA)
/* aliases */
#define PNG_COLOR_TYPE_RGBA PNG_COLOR_TYPE_RGB_ALPHA
#define PNG_COLOR_TYPE_GA PNG_COLOR_TYPE_GRAY_ALPHA
/* This is for compression type. PNG 1.0-1.2 only define the single type. */
#define PNG_COMPRESSION_TYPE_BASE 0 /* Deflate method 8, 32K window */
#define PNG_COMPRESSION_TYPE_DEFAULT PNG_COMPRESSION_TYPE_BASE
/* This is for filter method. PNG 1.0-1.2 only defines a single method.
*
* NOTE: CONFUSING NAME. The specification refers to a 'method', one of the
* defines below, and a 'type', one of the FILTER_VALUE defines.
* Historically libpng uses TYPE for 'method' and VALUE for 'type'.
*/
#define PNG_FILTER_TYPE_BASE 0 /* Single row per-byte filtering */
#define PNG_INTRAPIXEL_DIFFERENCING 64 /* Used only in MNG datastreams */
#define PNG_FILTER_TYPE_DEFAULT PNG_FILTER_TYPE_BASE
/* Filter values defined for method '0' (PNG_FILTER_TYPE_BASE) in the PNG
* specification.
*/
#define PNG_FILTER_VALUE_NONE 0
#define PNG_FILTER_VALUE_SUB 1
#define PNG_FILTER_VALUE_UP 2
#define PNG_FILTER_VALUE_AVG 3
#define PNG_FILTER_VALUE_PAETH 4
#define PNG_FILTER_VALUE_LAST 5 /* Not a valid value */
/* These are for the interlacing type. These values should NOT be changed. */
#define PNG_INTERLACE_NONE 0 /* Non-interlaced image */
#define PNG_INTERLACE_ADAM7 1 /* Adam7 interlacing */
#define PNG_INTERLACE_LAST 2 /* Not a valid value */
/* These are for the oFFs chunk. These values should NOT be changed. */
#define PNG_OFFSET_PIXEL 0 /* Offset in pixels */
#define PNG_OFFSET_MICROMETER 1 /* Offset in micrometers (1/10^6 meter) */
#define PNG_OFFSET_LAST 2 /* Not a valid value */
/* These are for the pCAL chunk. These values should NOT be changed. */
#define PNG_EQUATION_LINEAR 0 /* Linear transformation */
#define PNG_EQUATION_BASE_E 1 /* Exponential base e transform */
#define PNG_EQUATION_ARBITRARY 2 /* Arbitrary base exponential transform */
#define PNG_EQUATION_HYPERBOLIC 3 /* Hyperbolic sine transformation */
#define PNG_EQUATION_LAST 4 /* Not a valid value */
/* These are for the sCAL chunk. These values should NOT be changed. */
#define PNG_SCALE_UNKNOWN 0 /* unknown unit (image scale) */
#define PNG_SCALE_METER 1 /* meters per pixel */
#define PNG_SCALE_RADIAN 2 /* radians per pixel */
#define PNG_SCALE_LAST 3 /* Not a valid value */
/* These are for the pHYs chunk. These values should NOT be changed. */
#define PNG_RESOLUTION_UNKNOWN 0 /* pixels/unknown unit (aspect ratio) */
#define PNG_RESOLUTION_METER 1 /* pixels/meter */
#define PNG_RESOLUTION_LAST 2 /* Not a valid value */
/* These are for the sRGB chunk. These values should NOT be changed. */
#define PNG_sRGB_INTENT_PERCEPTUAL 0
#define PNG_sRGB_INTENT_RELATIVE 1
#define PNG_sRGB_INTENT_SATURATION 2
#define PNG_sRGB_INTENT_ABSOLUTE 3
#define PNG_sRGB_INTENT_LAST 4 /* Not a valid value */
/* This is for text chunks */
#define PNG_KEYWORD_MAX_LENGTH 79
/* Maximum number of entries in PLTE/sPLT/tRNS arrays */
#define PNG_MAX_PALETTE_LENGTH 256
/* These determine if an ancillary chunk's data has been successfully read
* from the PNG header, or if the application has filled in the corresponding
* data in the info_struct to be written into the output file. The values
* of the PNG_INFO_<chunk> defines should NOT be changed.
*/
#define PNG_INFO_gAMA 0x0001U
#define PNG_INFO_sBIT 0x0002U
#define PNG_INFO_cHRM 0x0004U
#define PNG_INFO_PLTE 0x0008U
#define PNG_INFO_tRNS 0x0010U
#define PNG_INFO_bKGD 0x0020U
#define PNG_INFO_hIST 0x0040U
#define PNG_INFO_pHYs 0x0080U
#define PNG_INFO_oFFs 0x0100U
#define PNG_INFO_tIME 0x0200U
#define PNG_INFO_pCAL 0x0400U
#define PNG_INFO_sRGB 0x0800U /* GR-P, 0.96a */
#define PNG_INFO_iCCP 0x1000U /* ESR, 1.0.6 */
#define PNG_INFO_sPLT 0x2000U /* ESR, 1.0.6 */
#define PNG_INFO_sCAL 0x4000U /* ESR, 1.0.6 */
#define PNG_INFO_IDAT 0x8000U /* ESR, 1.0.6 */
/* This is used for the transformation routines, as some of them
* change these values for the row. It also should enable using
* the routines for other purposes.
*/
typedef struct png_row_info_struct
{
png_uint_32 width; /* width of row */
size_t rowbytes; /* number of bytes in row */
png_byte color_type; /* color type of row */
png_byte bit_depth; /* bit depth of row */
png_byte channels; /* number of channels (1, 2, 3, or 4) */
png_byte pixel_depth; /* bits per pixel (depth * channels) */
} png_row_info;
typedef png_row_info * png_row_infop;
typedef png_row_info * * png_row_infopp;
/* These are the function types for the I/O functions and for the functions
* that allow the user to override the default I/O functions with his or her
* own. The png_error_ptr type should match that of user-supplied warning
* and error functions, while the png_rw_ptr type should match that of the
* user read/write data functions. Note that the 'write' function must not
* modify the buffer it is passed. The 'read' function, on the other hand, is
* expected to return the read data in the buffer.
*/
typedef PNG_CALLBACK(void, *png_error_ptr, (png_structp, png_const_charp));
typedef PNG_CALLBACK(void, *png_rw_ptr, (png_structp, png_bytep, size_t));
typedef PNG_CALLBACK(void, *png_flush_ptr, (png_structp));
typedef PNG_CALLBACK(void, *png_read_status_ptr, (png_structp, png_uint_32,
int));
typedef PNG_CALLBACK(void, *png_write_status_ptr, (png_structp, png_uint_32,
int));
#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
typedef PNG_CALLBACK(void, *png_progressive_info_ptr, (png_structp, png_infop));
typedef PNG_CALLBACK(void, *png_progressive_end_ptr, (png_structp, png_infop));
/* WARNING: the API for this callback is poorly documented and produces
* unexpected results when dealing with interlaced images. For non-interlaced
* images the parameters are straightforward:
*
* next_row: a pointer to the transformed row read from the PNG input
* stream, it has png_get_image_width() pixels.
* row_y: the y ordinate of the image; 0..png_get_image_height()-1
* pass: 0
*
* For interlaced images if png_set_interlace_handling has been called (libpng
* does *not* call this itself) the parameters are the same except that the
* pass will be the pass in the range 0..6 (NOTE: one less than the PNG spec)
* and 'next_row' will be NULL if (and only if) the row does not contribute
* to the output in 'blocky' display mode.
*
* pass: 0..6
*
* If 'next_row' is not NULL it is necessary for the application to combine the
* pixels with the output. This can most easily be done by calling
* png_progressive_combine_row(). Note that the 'next_row' data cannot be
* changed; even though the value is passed to png_progressive_combine_row the
* pointer is not used, it is just a flag , if it is NULL nothing will happen.
*