-
Notifications
You must be signed in to change notification settings - Fork 589
/
png.c
4559 lines (3989 loc) · 152 KB
/
png.c
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.c - location for general purpose libpng functions
*
* Copyright (c) 2018-2024 Cosmin Truta
* Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
* Copyright (c) 1996-1997 Andreas Dilger
* Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
*
* This code is released under the libpng license.
* For conditions of distribution and use, see the disclaimer
* and license in png.h
*/
#include "pngpriv.h"
/* Generate a compiler error if there is an old png.h in the search path. */
typedef png_libpng_version_1_6_44_git Your_png_h_is_not_version_1_6_44_git;
/* Tells libpng that we have already handled the first "num_bytes" bytes
* of the PNG file signature. If the PNG data is embedded into another
* stream we can set num_bytes = 8 so that libpng will not attempt to read
* or write any of the magic bytes before it starts on the IHDR.
*/
#ifdef PNG_READ_SUPPORTED
void PNGAPI
png_set_sig_bytes(png_structrp png_ptr, int num_bytes)
{
unsigned int nb = (unsigned int)num_bytes;
png_debug(1, "in png_set_sig_bytes");
if (png_ptr == NULL)
return;
if (num_bytes < 0)
nb = 0;
if (nb > 8)
png_error(png_ptr, "Too many bytes for PNG signature");
png_ptr->sig_bytes = (png_byte)nb;
}
/* Checks whether the supplied bytes match the PNG signature. We allow
* checking less than the full 8-byte signature so that those apps that
* already read the first few bytes of a file to determine the file type
* can simply check the remaining bytes for extra assurance. Returns
* an integer less than, equal to, or greater than zero if sig is found,
* respectively, to be less than, to match, or be greater than the correct
* PNG signature (this is the same behavior as strcmp, memcmp, etc).
*/
int PNGAPI
png_sig_cmp(png_const_bytep sig, size_t start, size_t num_to_check)
{
static const png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
if (num_to_check > 8)
num_to_check = 8;
else if (num_to_check < 1)
return -1;
if (start > 7)
return -1;
if (start + num_to_check > 8)
num_to_check = 8 - start;
return memcmp(&sig[start], &png_signature[start], num_to_check);
}
#endif /* READ */
#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
/* Function to allocate memory for zlib */
PNG_FUNCTION(voidpf /* PRIVATE */,
png_zalloc,(voidpf png_ptr, uInt items, uInt size),PNG_ALLOCATED)
{
png_alloc_size_t num_bytes = size;
if (png_ptr == NULL)
return NULL;
if (items >= (~(png_alloc_size_t)0)/size)
{
png_warning (png_voidcast(png_structrp, png_ptr),
"Potential overflow in png_zalloc()");
return NULL;
}
num_bytes *= items;
return png_malloc_warn(png_voidcast(png_structrp, png_ptr), num_bytes);
}
/* Function to free memory for zlib */
void /* PRIVATE */
png_zfree(voidpf png_ptr, voidpf ptr)
{
png_free(png_voidcast(png_const_structrp,png_ptr), ptr);
}
/* Reset the CRC variable to 32 bits of 1's. Care must be taken
* in case CRC is > 32 bits to leave the top bits 0.
*/
void /* PRIVATE */
png_reset_crc(png_structrp png_ptr)
{
/* The cast is safe because the crc is a 32-bit value. */
png_ptr->crc = (png_uint_32)crc32(0, Z_NULL, 0);
}
/* Calculate the CRC over a section of data. We can only pass as
* much data to this routine as the largest single buffer size. We
* also check that this data will actually be used before going to the
* trouble of calculating it.
*/
void /* PRIVATE */
png_calculate_crc(png_structrp png_ptr, png_const_bytep ptr, size_t length)
{
int need_crc = 1;
if (PNG_CHUNK_ANCILLARY(png_ptr->chunk_name) != 0)
{
if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
(PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
need_crc = 0;
}
else /* critical */
{
if ((png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE) != 0)
need_crc = 0;
}
/* 'uLong' is defined in zlib.h as unsigned long; this means that on some
* systems it is a 64-bit value. crc32, however, returns 32 bits so the
* following cast is safe. 'uInt' may be no more than 16 bits, so it is
* necessary to perform a loop here.
*/
if (need_crc != 0 && length > 0)
{
uLong crc = png_ptr->crc; /* Should never issue a warning */
do
{
uInt safe_length = (uInt)length;
#ifndef __COVERITY__
if (safe_length == 0)
safe_length = (uInt)-1; /* evil, but safe */
#endif
crc = crc32(crc, ptr, safe_length);
/* The following should never issue compiler warnings; if they do the
* target system has characteristics that will probably violate other
* assumptions within the libpng code.
*/
ptr += safe_length;
length -= safe_length;
}
while (length > 0);
/* And the following is always safe because the crc is only 32 bits. */
png_ptr->crc = (png_uint_32)crc;
}
}
/* Check a user supplied version number, called from both read and write
* functions that create a png_struct.
*/
int
png_user_version_check(png_structrp png_ptr, png_const_charp user_png_ver)
{
/* Libpng versions 1.0.0 and later are binary compatible if the version
* string matches through the second '.'; we must recompile any
* applications that use any older library version.
*/
if (user_png_ver != NULL)
{
int i = -1;
int found_dots = 0;
do
{
i++;
if (user_png_ver[i] != PNG_LIBPNG_VER_STRING[i])
png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
if (user_png_ver[i] == '.')
found_dots++;
} while (found_dots < 2 && user_png_ver[i] != 0 &&
PNG_LIBPNG_VER_STRING[i] != 0);
}
else
png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
if ((png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH) != 0)
{
#ifdef PNG_WARNINGS_SUPPORTED
size_t pos = 0;
char m[128];
pos = png_safecat(m, (sizeof m), pos,
"Application built with libpng-");
pos = png_safecat(m, (sizeof m), pos, user_png_ver);
pos = png_safecat(m, (sizeof m), pos, " but running with ");
pos = png_safecat(m, (sizeof m), pos, PNG_LIBPNG_VER_STRING);
PNG_UNUSED(pos)
png_warning(png_ptr, m);
#endif
#ifdef PNG_ERROR_NUMBERS_SUPPORTED
png_ptr->flags = 0;
#endif
return 0;
}
/* Success return. */
return 1;
}
/* Generic function to create a png_struct for either read or write - this
* contains the common initialization.
*/
PNG_FUNCTION(png_structp /* PRIVATE */,
png_create_png_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED)
{
png_struct create_struct;
# ifdef PNG_SETJMP_SUPPORTED
jmp_buf create_jmp_buf;
# endif
/* This temporary stack-allocated structure is used to provide a place to
* build enough context to allow the user provided memory allocator (if any)
* to be called.
*/
memset(&create_struct, 0, (sizeof create_struct));
/* Added at libpng-1.2.6 */
# ifdef PNG_USER_LIMITS_SUPPORTED
create_struct.user_width_max = PNG_USER_WIDTH_MAX;
create_struct.user_height_max = PNG_USER_HEIGHT_MAX;
# ifdef PNG_USER_CHUNK_CACHE_MAX
/* Added at libpng-1.2.43 and 1.4.0 */
create_struct.user_chunk_cache_max = PNG_USER_CHUNK_CACHE_MAX;
# endif
# ifdef PNG_USER_CHUNK_MALLOC_MAX
/* Added at libpng-1.2.43 and 1.4.1, required only for read but exists
* in png_struct regardless.
*/
create_struct.user_chunk_malloc_max = PNG_USER_CHUNK_MALLOC_MAX;
# endif
# endif
/* The following two API calls simply set fields in png_struct, so it is safe
* to do them now even though error handling is not yet set up.
*/
# ifdef PNG_USER_MEM_SUPPORTED
png_set_mem_fn(&create_struct, mem_ptr, malloc_fn, free_fn);
# else
PNG_UNUSED(mem_ptr)
PNG_UNUSED(malloc_fn)
PNG_UNUSED(free_fn)
# endif
/* (*error_fn) can return control to the caller after the error_ptr is set,
* this will result in a memory leak unless the error_fn does something
* extremely sophisticated. The design lacks merit but is implicit in the
* API.
*/
png_set_error_fn(&create_struct, error_ptr, error_fn, warn_fn);
# ifdef PNG_SETJMP_SUPPORTED
if (!setjmp(create_jmp_buf))
# endif
{
# ifdef PNG_SETJMP_SUPPORTED
/* Temporarily fake out the longjmp information until we have
* successfully completed this function. This only works if we have
* setjmp() support compiled in, but it is safe - this stuff should
* never happen.
*/
create_struct.jmp_buf_ptr = &create_jmp_buf;
create_struct.jmp_buf_size = 0; /*stack allocation*/
create_struct.longjmp_fn = longjmp;
# endif
/* Call the general version checker (shared with read and write code):
*/
if (png_user_version_check(&create_struct, user_png_ver) != 0)
{
png_structrp png_ptr = png_voidcast(png_structrp,
png_malloc_warn(&create_struct, (sizeof *png_ptr)));
if (png_ptr != NULL)
{
/* png_ptr->zstream holds a back-pointer to the png_struct, so
* this can only be done now:
*/
create_struct.zstream.zalloc = png_zalloc;
create_struct.zstream.zfree = png_zfree;
create_struct.zstream.opaque = png_ptr;
# ifdef PNG_SETJMP_SUPPORTED
/* Eliminate the local error handling: */
create_struct.jmp_buf_ptr = NULL;
create_struct.jmp_buf_size = 0;
create_struct.longjmp_fn = 0;
# endif
*png_ptr = create_struct;
/* This is the successful return point */
return png_ptr;
}
}
}
/* A longjmp because of a bug in the application storage allocator or a
* simple failure to allocate the png_struct.
*/
return NULL;
}
/* Allocate the memory for an info_struct for the application. */
PNG_FUNCTION(png_infop,PNGAPI
png_create_info_struct,(png_const_structrp png_ptr),PNG_ALLOCATED)
{
png_inforp info_ptr;
png_debug(1, "in png_create_info_struct");
if (png_ptr == NULL)
return NULL;
/* Use the internal API that does not (or at least should not) error out, so
* that this call always returns ok. The application typically sets up the
* error handling *after* creating the info_struct because this is the way it
* has always been done in 'example.c'.
*/
info_ptr = png_voidcast(png_inforp, png_malloc_base(png_ptr,
(sizeof *info_ptr)));
if (info_ptr != NULL)
memset(info_ptr, 0, (sizeof *info_ptr));
return info_ptr;
}
/* This function frees the memory associated with a single info struct.
* Normally, one would use either png_destroy_read_struct() or
* png_destroy_write_struct() to free an info struct, but this may be
* useful for some applications. From libpng 1.6.0 this function is also used
* internally to implement the png_info release part of the 'struct' destroy
* APIs. This ensures that all possible approaches free the same data (all of
* it).
*/
void PNGAPI
png_destroy_info_struct(png_const_structrp png_ptr, png_infopp info_ptr_ptr)
{
png_inforp info_ptr = NULL;
png_debug(1, "in png_destroy_info_struct");
if (png_ptr == NULL)
return;
if (info_ptr_ptr != NULL)
info_ptr = *info_ptr_ptr;
if (info_ptr != NULL)
{
/* Do this first in case of an error below; if the app implements its own
* memory management this can lead to png_free calling png_error, which
* will abort this routine and return control to the app error handler.
* An infinite loop may result if it then tries to free the same info
* ptr.
*/
*info_ptr_ptr = NULL;
png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
memset(info_ptr, 0, (sizeof *info_ptr));
png_free(png_ptr, info_ptr);
}
}
/* Initialize the info structure. This is now an internal function (0.89)
* and applications using it are urged to use png_create_info_struct()
* instead. Use deprecated in 1.6.0, internal use removed (used internally it
* is just a memset).
*
* NOTE: it is almost inconceivable that this API is used because it bypasses
* the user-memory mechanism and the user error handling/warning mechanisms in
* those cases where it does anything other than a memset.
*/
PNG_FUNCTION(void,PNGAPI
png_info_init_3,(png_infopp ptr_ptr, size_t png_info_struct_size),
PNG_DEPRECATED)
{
png_inforp info_ptr = *ptr_ptr;
png_debug(1, "in png_info_init_3");
if (info_ptr == NULL)
return;
if ((sizeof (png_info)) > png_info_struct_size)
{
*ptr_ptr = NULL;
/* The following line is why this API should not be used: */
free(info_ptr);
info_ptr = png_voidcast(png_inforp, png_malloc_base(NULL,
(sizeof *info_ptr)));
if (info_ptr == NULL)
return;
*ptr_ptr = info_ptr;
}
/* Set everything to 0 */
memset(info_ptr, 0, (sizeof *info_ptr));
}
void PNGAPI
png_data_freer(png_const_structrp png_ptr, png_inforp info_ptr,
int freer, png_uint_32 mask)
{
png_debug(1, "in png_data_freer");
if (png_ptr == NULL || info_ptr == NULL)
return;
if (freer == PNG_DESTROY_WILL_FREE_DATA)
info_ptr->free_me |= mask;
else if (freer == PNG_USER_WILL_FREE_DATA)
info_ptr->free_me &= ~mask;
else
png_error(png_ptr, "Unknown freer parameter in png_data_freer");
}
void PNGAPI
png_free_data(png_const_structrp png_ptr, png_inforp info_ptr, png_uint_32 mask,
int num)
{
png_debug(1, "in png_free_data");
if (png_ptr == NULL || info_ptr == NULL)
return;
#ifdef PNG_TEXT_SUPPORTED
/* Free text item num or (if num == -1) all text items */
if (info_ptr->text != NULL &&
((mask & PNG_FREE_TEXT) & info_ptr->free_me) != 0)
{
if (num != -1)
{
png_free(png_ptr, info_ptr->text[num].key);
info_ptr->text[num].key = NULL;
}
else
{
int i;
for (i = 0; i < info_ptr->num_text; i++)
png_free(png_ptr, info_ptr->text[i].key);
png_free(png_ptr, info_ptr->text);
info_ptr->text = NULL;
info_ptr->num_text = 0;
info_ptr->max_text = 0;
}
}
#endif
#ifdef PNG_tRNS_SUPPORTED
/* Free any tRNS entry */
if (((mask & PNG_FREE_TRNS) & info_ptr->free_me) != 0)
{
info_ptr->valid &= ~PNG_INFO_tRNS;
png_free(png_ptr, info_ptr->trans_alpha);
info_ptr->trans_alpha = NULL;
info_ptr->num_trans = 0;
}
#endif
#ifdef PNG_sCAL_SUPPORTED
/* Free any sCAL entry */
if (((mask & PNG_FREE_SCAL) & info_ptr->free_me) != 0)
{
png_free(png_ptr, info_ptr->scal_s_width);
png_free(png_ptr, info_ptr->scal_s_height);
info_ptr->scal_s_width = NULL;
info_ptr->scal_s_height = NULL;
info_ptr->valid &= ~PNG_INFO_sCAL;
}
#endif
#ifdef PNG_pCAL_SUPPORTED
/* Free any pCAL entry */
if (((mask & PNG_FREE_PCAL) & info_ptr->free_me) != 0)
{
png_free(png_ptr, info_ptr->pcal_purpose);
png_free(png_ptr, info_ptr->pcal_units);
info_ptr->pcal_purpose = NULL;
info_ptr->pcal_units = NULL;
if (info_ptr->pcal_params != NULL)
{
int i;
for (i = 0; i < info_ptr->pcal_nparams; i++)
png_free(png_ptr, info_ptr->pcal_params[i]);
png_free(png_ptr, info_ptr->pcal_params);
info_ptr->pcal_params = NULL;
}
info_ptr->valid &= ~PNG_INFO_pCAL;
}
#endif
#ifdef PNG_iCCP_SUPPORTED
/* Free any profile entry */
if (((mask & PNG_FREE_ICCP) & info_ptr->free_me) != 0)
{
png_free(png_ptr, info_ptr->iccp_name);
png_free(png_ptr, info_ptr->iccp_profile);
info_ptr->iccp_name = NULL;
info_ptr->iccp_profile = NULL;
info_ptr->valid &= ~PNG_INFO_iCCP;
}
#endif
#ifdef PNG_sPLT_SUPPORTED
/* Free a given sPLT entry, or (if num == -1) all sPLT entries */
if (info_ptr->splt_palettes != NULL &&
((mask & PNG_FREE_SPLT) & info_ptr->free_me) != 0)
{
if (num != -1)
{
png_free(png_ptr, info_ptr->splt_palettes[num].name);
png_free(png_ptr, info_ptr->splt_palettes[num].entries);
info_ptr->splt_palettes[num].name = NULL;
info_ptr->splt_palettes[num].entries = NULL;
}
else
{
int i;
for (i = 0; i < info_ptr->splt_palettes_num; i++)
{
png_free(png_ptr, info_ptr->splt_palettes[i].name);
png_free(png_ptr, info_ptr->splt_palettes[i].entries);
}
png_free(png_ptr, info_ptr->splt_palettes);
info_ptr->splt_palettes = NULL;
info_ptr->splt_palettes_num = 0;
info_ptr->valid &= ~PNG_INFO_sPLT;
}
}
#endif
#ifdef PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED
if (info_ptr->unknown_chunks != NULL &&
((mask & PNG_FREE_UNKN) & info_ptr->free_me) != 0)
{
if (num != -1)
{
png_free(png_ptr, info_ptr->unknown_chunks[num].data);
info_ptr->unknown_chunks[num].data = NULL;
}
else
{
int i;
for (i = 0; i < info_ptr->unknown_chunks_num; i++)
png_free(png_ptr, info_ptr->unknown_chunks[i].data);
png_free(png_ptr, info_ptr->unknown_chunks);
info_ptr->unknown_chunks = NULL;
info_ptr->unknown_chunks_num = 0;
}
}
#endif
#ifdef PNG_eXIf_SUPPORTED
/* Free any eXIf entry */
if (((mask & PNG_FREE_EXIF) & info_ptr->free_me) != 0)
{
# ifdef PNG_READ_eXIf_SUPPORTED
if (info_ptr->eXIf_buf)
{
png_free(png_ptr, info_ptr->eXIf_buf);
info_ptr->eXIf_buf = NULL;
}
# endif
if (info_ptr->exif)
{
png_free(png_ptr, info_ptr->exif);
info_ptr->exif = NULL;
}
info_ptr->valid &= ~PNG_INFO_eXIf;
}
#endif
#ifdef PNG_hIST_SUPPORTED
/* Free any hIST entry */
if (((mask & PNG_FREE_HIST) & info_ptr->free_me) != 0)
{
png_free(png_ptr, info_ptr->hist);
info_ptr->hist = NULL;
info_ptr->valid &= ~PNG_INFO_hIST;
}
#endif
/* Free any PLTE entry that was internally allocated */
if (((mask & PNG_FREE_PLTE) & info_ptr->free_me) != 0)
{
png_free(png_ptr, info_ptr->palette);
info_ptr->palette = NULL;
info_ptr->valid &= ~PNG_INFO_PLTE;
info_ptr->num_palette = 0;
}
#ifdef PNG_INFO_IMAGE_SUPPORTED
/* Free any image bits attached to the info structure */
if (((mask & PNG_FREE_ROWS) & info_ptr->free_me) != 0)
{
if (info_ptr->row_pointers != NULL)
{
png_uint_32 row;
for (row = 0; row < info_ptr->height; row++)
png_free(png_ptr, info_ptr->row_pointers[row]);
png_free(png_ptr, info_ptr->row_pointers);
info_ptr->row_pointers = NULL;
}
info_ptr->valid &= ~PNG_INFO_IDAT;
}
#endif
if (num != -1)
mask &= ~PNG_FREE_MUL;
info_ptr->free_me &= ~mask;
}
#endif /* READ || WRITE */
/* This function returns a pointer to the io_ptr associated with the user
* functions. The application should free any memory associated with this
* pointer before png_write_destroy() or png_read_destroy() are called.
*/
png_voidp PNGAPI
png_get_io_ptr(png_const_structrp png_ptr)
{
if (png_ptr == NULL)
return NULL;
return png_ptr->io_ptr;
}
#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
# ifdef PNG_STDIO_SUPPORTED
/* Initialize the default input/output functions for the PNG file. If you
* use your own read or write routines, you can call either png_set_read_fn()
* or png_set_write_fn() instead of png_init_io(). If you have defined
* PNG_NO_STDIO or otherwise disabled PNG_STDIO_SUPPORTED, you must use a
* function of your own because "FILE *" isn't necessarily available.
*/
void PNGAPI
png_init_io(png_structrp png_ptr, png_FILE_p fp)
{
png_debug(1, "in png_init_io");
if (png_ptr == NULL)
return;
png_ptr->io_ptr = (png_voidp)fp;
}
# endif
# ifdef PNG_SAVE_INT_32_SUPPORTED
/* PNG signed integers are saved in 32-bit 2's complement format. ANSI C-90
* defines a cast of a signed integer to an unsigned integer either to preserve
* the value, if it is positive, or to calculate:
*
* (UNSIGNED_MAX+1) + integer
*
* Where UNSIGNED_MAX is the appropriate maximum unsigned value, so when the
* negative integral value is added the result will be an unsigned value
* corresponding to the 2's complement representation.
*/
void PNGAPI
png_save_int_32(png_bytep buf, png_int_32 i)
{
png_save_uint_32(buf, (png_uint_32)i);
}
# endif
# ifdef PNG_TIME_RFC1123_SUPPORTED
/* Convert the supplied time into an RFC 1123 string suitable for use in
* a "Creation Time" or other text-based time string.
*/
int PNGAPI
png_convert_to_rfc1123_buffer(char out[29], png_const_timep ptime)
{
static const char short_months[12][4] =
{"Jan", "Feb", "Mar", "Apr", "May", "Jun",
"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
if (out == NULL)
return 0;
if (ptime->year > 9999 /* RFC1123 limitation */ ||
ptime->month == 0 || ptime->month > 12 ||
ptime->day == 0 || ptime->day > 31 ||
ptime->hour > 23 || ptime->minute > 59 ||
ptime->second > 60)
return 0;
{
size_t pos = 0;
char number_buf[5] = {0, 0, 0, 0, 0}; /* enough for a four-digit year */
# define APPEND_STRING(string) pos = png_safecat(out, 29, pos, (string))
# define APPEND_NUMBER(format, value)\
APPEND_STRING(PNG_FORMAT_NUMBER(number_buf, format, (value)))
# define APPEND(ch) if (pos < 28) out[pos++] = (ch)
APPEND_NUMBER(PNG_NUMBER_FORMAT_u, (unsigned)ptime->day);
APPEND(' ');
APPEND_STRING(short_months[(ptime->month - 1)]);
APPEND(' ');
APPEND_NUMBER(PNG_NUMBER_FORMAT_u, ptime->year);
APPEND(' ');
APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->hour);
APPEND(':');
APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->minute);
APPEND(':');
APPEND_NUMBER(PNG_NUMBER_FORMAT_02u, (unsigned)ptime->second);
APPEND_STRING(" +0000"); /* This reliably terminates the buffer */
PNG_UNUSED (pos)
# undef APPEND
# undef APPEND_NUMBER
# undef APPEND_STRING
}
return 1;
}
# if PNG_LIBPNG_VER < 10700
/* To do: remove the following from libpng-1.7 */
/* Original API that uses a private buffer in png_struct.
* Deprecated because it causes png_struct to carry a spurious temporary
* buffer (png_struct::time_buffer), better to have the caller pass this in.
*/
png_const_charp PNGAPI
png_convert_to_rfc1123(png_structrp png_ptr, png_const_timep ptime)
{
if (png_ptr != NULL)
{
/* The only failure above if png_ptr != NULL is from an invalid ptime */
if (png_convert_to_rfc1123_buffer(png_ptr->time_buffer, ptime) == 0)
png_warning(png_ptr, "Ignoring invalid time value");
else
return png_ptr->time_buffer;
}
return NULL;
}
# endif /* LIBPNG_VER < 10700 */
# endif /* TIME_RFC1123 */
#endif /* READ || WRITE */
png_const_charp PNGAPI
png_get_copyright(png_const_structrp png_ptr)
{
PNG_UNUSED(png_ptr) /* Silence compiler warning about unused png_ptr */
#ifdef PNG_STRING_COPYRIGHT
return PNG_STRING_COPYRIGHT
#else
return PNG_STRING_NEWLINE \
"libpng version 1.6.44.git" PNG_STRING_NEWLINE \
"Copyright (c) 2018-2024 Cosmin Truta" PNG_STRING_NEWLINE \
"Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson" \
PNG_STRING_NEWLINE \
"Copyright (c) 1996-1997 Andreas Dilger" PNG_STRING_NEWLINE \
"Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc." \
PNG_STRING_NEWLINE;
#endif
}
/* The following return the library version as a short string in the
* format 1.0.0 through 99.99.99zz. To get the version of *.h files
* used with your application, print out PNG_LIBPNG_VER_STRING, which
* is defined in png.h.
* Note: now there is no difference between png_get_libpng_ver() and
* png_get_header_ver(). Due to the version_nn_nn_nn typedef guard,
* it is guaranteed that png.c uses the correct version of png.h.
*/
png_const_charp PNGAPI
png_get_libpng_ver(png_const_structrp png_ptr)
{
/* Version of *.c files used when building libpng */
return png_get_header_ver(png_ptr);
}
png_const_charp PNGAPI
png_get_header_ver(png_const_structrp png_ptr)
{
/* Version of *.h files used when building libpng */
PNG_UNUSED(png_ptr) /* Silence compiler warning about unused png_ptr */
return PNG_LIBPNG_VER_STRING;
}
png_const_charp PNGAPI
png_get_header_version(png_const_structrp png_ptr)
{
/* Returns longer string containing both version and date */
PNG_UNUSED(png_ptr) /* Silence compiler warning about unused png_ptr */
#ifdef __STDC__
return PNG_HEADER_VERSION_STRING
# ifndef PNG_READ_SUPPORTED
" (NO READ SUPPORT)"
# endif
PNG_STRING_NEWLINE;
#else
return PNG_HEADER_VERSION_STRING;
#endif
}
#ifdef PNG_BUILD_GRAYSCALE_PALETTE_SUPPORTED
/* NOTE: this routine is not used internally! */
/* Build a grayscale palette. Palette is assumed to be 1 << bit_depth
* large of png_color. This lets grayscale images be treated as
* paletted. Most useful for gamma correction and simplification
* of code. This API is not used internally.
*/
void PNGAPI
png_build_grayscale_palette(int bit_depth, png_colorp palette)
{
int num_palette;
int color_inc;
int i;
int v;
png_debug(1, "in png_do_build_grayscale_palette");
if (palette == NULL)
return;
switch (bit_depth)
{
case 1:
num_palette = 2;
color_inc = 0xff;
break;
case 2:
num_palette = 4;
color_inc = 0x55;
break;
case 4:
num_palette = 16;
color_inc = 0x11;
break;
case 8:
num_palette = 256;
color_inc = 1;
break;
default:
num_palette = 0;
color_inc = 0;
break;
}
for (i = 0, v = 0; i < num_palette; i++, v += color_inc)
{
palette[i].red = (png_byte)(v & 0xff);
palette[i].green = (png_byte)(v & 0xff);
palette[i].blue = (png_byte)(v & 0xff);
}
}
#endif
#ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
int PNGAPI
png_handle_as_unknown(png_const_structrp png_ptr, png_const_bytep chunk_name)
{
/* Check chunk_name and return "keep" value if it's on the list, else 0 */
png_const_bytep p, p_end;
if (png_ptr == NULL || chunk_name == NULL || png_ptr->num_chunk_list == 0)
return PNG_HANDLE_CHUNK_AS_DEFAULT;
p_end = png_ptr->chunk_list;
p = p_end + png_ptr->num_chunk_list*5; /* beyond end */
/* The code is the fifth byte after each four byte string. Historically this
* code was always searched from the end of the list, this is no longer
* necessary because the 'set' routine handles duplicate entries correctly.
*/
do /* num_chunk_list > 0, so at least one */
{
p -= 5;
if (memcmp(chunk_name, p, 4) == 0)
return p[4];
}
while (p > p_end);
/* This means that known chunks should be processed and unknown chunks should
* be handled according to the value of png_ptr->unknown_default; this can be
* confusing because, as a result, there are two levels of defaulting for
* unknown chunks.
*/
return PNG_HANDLE_CHUNK_AS_DEFAULT;
}
#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED) ||\
defined(PNG_HANDLE_AS_UNKNOWN_SUPPORTED)
int /* PRIVATE */
png_chunk_unknown_handling(png_const_structrp png_ptr, png_uint_32 chunk_name)
{
png_byte chunk_string[5];
PNG_CSTRING_FROM_CHUNK(chunk_string, chunk_name);
return png_handle_as_unknown(png_ptr, chunk_string);
}
#endif /* READ_UNKNOWN_CHUNKS || HANDLE_AS_UNKNOWN */
#endif /* SET_UNKNOWN_CHUNKS */
#ifdef PNG_READ_SUPPORTED
/* This function, added to libpng-1.0.6g, is untested. */
int PNGAPI
png_reset_zstream(png_structrp png_ptr)
{
if (png_ptr == NULL)
return Z_STREAM_ERROR;
/* WARNING: this resets the window bits to the maximum! */
return inflateReset(&png_ptr->zstream);
}
#endif /* READ */
/* This function was added to libpng-1.0.7 */
png_uint_32 PNGAPI
png_access_version_number(void)
{
/* Version of *.c files used when building libpng */
return (png_uint_32)PNG_LIBPNG_VER;
}
#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
/* Ensure that png_ptr->zstream.msg holds some appropriate error message string.
* If it doesn't 'ret' is used to set it to something appropriate, even in cases
* like Z_OK or Z_STREAM_END where the error code is apparently a success code.
*/
void /* PRIVATE */
png_zstream_error(png_structrp png_ptr, int ret)
{
/* Translate 'ret' into an appropriate error string, priority is given to the
* one in zstream if set. This always returns a string, even in cases like
* Z_OK or Z_STREAM_END where the error code is a success code.
*/
if (png_ptr->zstream.msg == NULL) switch (ret)
{
default:
case Z_OK:
png_ptr->zstream.msg = PNGZ_MSG_CAST("unexpected zlib return code");
break;
case Z_STREAM_END:
/* Normal exit */
png_ptr->zstream.msg = PNGZ_MSG_CAST("unexpected end of LZ stream");
break;
case Z_NEED_DICT:
/* This means the deflate stream did not have a dictionary; this
* indicates a bogus PNG.
*/
png_ptr->zstream.msg = PNGZ_MSG_CAST("missing LZ dictionary");
break;