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comparison: media/libpng/pngpread.c

media/libpng/pngpread.c

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1
2 /* pngpread.c - read a png file in push mode
3 *
4 * Last changed in libpng 1.6.10 [March 6, 2014]
5 * Copyright (c) 1998-2014 Glenn Randers-Pehrson
6 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
7 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
8 *
9 * This code is released under the libpng license.
10 * For conditions of distribution and use, see the disclaimer
11 * and license in png.h
12 */
13
14 #include "pngpriv.h"
15
16 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
17
18 /* Push model modes */
19 #define PNG_READ_SIG_MODE 0
20 #define PNG_READ_CHUNK_MODE 1
21 #define PNG_READ_IDAT_MODE 2
22 #define PNG_SKIP_MODE 3
23 #define PNG_READ_tEXt_MODE 4
24 #define PNG_READ_zTXt_MODE 5
25 #define PNG_READ_DONE_MODE 6
26 #define PNG_READ_iTXt_MODE 7
27 #define PNG_ERROR_MODE 8
28
29 void PNGAPI
30 png_process_data(png_structrp png_ptr, png_inforp info_ptr,
31 png_bytep buffer, png_size_t buffer_size)
32 {
33 if (png_ptr == NULL || info_ptr == NULL)
34 return;
35
36 png_push_restore_buffer(png_ptr, buffer, buffer_size);
37
38 while (png_ptr->buffer_size)
39 {
40 png_process_some_data(png_ptr, info_ptr);
41 }
42 }
43
44 png_size_t PNGAPI
45 png_process_data_pause(png_structrp png_ptr, int save)
46 {
47 if (png_ptr != NULL)
48 {
49 /* It's easiest for the caller if we do the save, then the caller doesn't
50 * have to supply the same data again:
51 */
52 if (save)
53 png_push_save_buffer(png_ptr);
54 else
55 {
56 /* This includes any pending saved bytes: */
57 png_size_t remaining = png_ptr->buffer_size;
58 png_ptr->buffer_size = 0;
59
60 /* So subtract the saved buffer size, unless all the data
61 * is actually 'saved', in which case we just return 0
62 */
63 if (png_ptr->save_buffer_size < remaining)
64 return remaining - png_ptr->save_buffer_size;
65 }
66 }
67
68 return 0;
69 }
70
71 png_uint_32 PNGAPI
72 png_process_data_skip(png_structrp png_ptr)
73 {
74 png_uint_32 remaining = 0;
75
76 if (png_ptr != NULL && png_ptr->process_mode == PNG_SKIP_MODE &&
77 png_ptr->skip_length > 0)
78 {
79 /* At the end of png_process_data the buffer size must be 0 (see the loop
80 * above) so we can detect a broken call here:
81 */
82 if (png_ptr->buffer_size != 0)
83 png_error(png_ptr,
84 "png_process_data_skip called inside png_process_data");
85
86 /* If is impossible for there to be a saved buffer at this point -
87 * otherwise we could not be in SKIP mode. This will also happen if
88 * png_process_skip is called inside png_process_data (but only very
89 * rarely.)
90 */
91 if (png_ptr->save_buffer_size != 0)
92 png_error(png_ptr, "png_process_data_skip called with saved data");
93
94 remaining = png_ptr->skip_length;
95 png_ptr->skip_length = 0;
96 png_ptr->process_mode = PNG_READ_CHUNK_MODE;
97 }
98
99 return remaining;
100 }
101
102 /* What we do with the incoming data depends on what we were previously
103 * doing before we ran out of data...
104 */
105 void /* PRIVATE */
106 png_process_some_data(png_structrp png_ptr, png_inforp info_ptr)
107 {
108 if (png_ptr == NULL)
109 return;
110
111 switch (png_ptr->process_mode)
112 {
113 case PNG_READ_SIG_MODE:
114 {
115 png_push_read_sig(png_ptr, info_ptr);
116 break;
117 }
118
119 case PNG_READ_CHUNK_MODE:
120 {
121 png_push_read_chunk(png_ptr, info_ptr);
122 break;
123 }
124
125 case PNG_READ_IDAT_MODE:
126 {
127 png_push_read_IDAT(png_ptr);
128 break;
129 }
130
131 case PNG_SKIP_MODE:
132 {
133 png_push_crc_finish(png_ptr);
134 break;
135 }
136
137 default:
138 {
139 png_ptr->buffer_size = 0;
140 break;
141 }
142 }
143 }
144
145 /* Read any remaining signature bytes from the stream and compare them with
146 * the correct PNG signature. It is possible that this routine is called
147 * with bytes already read from the signature, either because they have been
148 * checked by the calling application, or because of multiple calls to this
149 * routine.
150 */
151 void /* PRIVATE */
152 png_push_read_sig(png_structrp png_ptr, png_inforp info_ptr)
153 {
154 png_size_t num_checked = png_ptr->sig_bytes, /* SAFE, does not exceed 8 */
155 num_to_check = 8 - num_checked;
156
157 if (png_ptr->buffer_size < num_to_check)
158 {
159 num_to_check = png_ptr->buffer_size;
160 }
161
162 png_push_fill_buffer(png_ptr, &(info_ptr->signature[num_checked]),
163 num_to_check);
164 png_ptr->sig_bytes = (png_byte)(png_ptr->sig_bytes + num_to_check);
165
166 if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
167 {
168 if (num_checked < 4 &&
169 png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
170 png_error(png_ptr, "Not a PNG file");
171
172 else
173 png_error(png_ptr, "PNG file corrupted by ASCII conversion");
174 }
175 else
176 {
177 if (png_ptr->sig_bytes >= 8)
178 {
179 png_ptr->process_mode = PNG_READ_CHUNK_MODE;
180 }
181 }
182 }
183
184 void /* PRIVATE */
185 png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
186 {
187 png_uint_32 chunk_name;
188 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
189 int keep; /* unknown handling method */
190 #endif
191
192 /* First we make sure we have enough data for the 4 byte chunk name
193 * and the 4 byte chunk length before proceeding with decoding the
194 * chunk data. To fully decode each of these chunks, we also make
195 * sure we have enough data in the buffer for the 4 byte CRC at the
196 * end of every chunk (except IDAT, which is handled separately).
197 */
198 if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
199 {
200 png_byte chunk_length[4];
201 png_byte chunk_tag[4];
202
203 if (png_ptr->buffer_size < 8)
204 {
205 png_push_save_buffer(png_ptr);
206 return;
207 }
208
209 png_push_fill_buffer(png_ptr, chunk_length, 4);
210 png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
211 png_reset_crc(png_ptr);
212 png_crc_read(png_ptr, chunk_tag, 4);
213 png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag);
214 png_check_chunk_name(png_ptr, png_ptr->chunk_name);
215 png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
216 }
217
218 chunk_name = png_ptr->chunk_name;
219
220 #ifdef PNG_READ_APNG_SUPPORTED
221 if (png_ptr->num_frames_read > 0 &&
222 png_ptr->num_frames_read < info_ptr->num_frames)
223 {
224 if (chunk_name == png_IDAT)
225 {
226 /* Discard trailing IDATs for the first frame */
227 if (png_ptr->mode & PNG_HAVE_fcTL || png_ptr->num_frames_read > 1)
228 png_error(png_ptr, "out of place IDAT");
229
230 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
231 {
232 png_push_save_buffer(png_ptr);
233 return;
234 }
235
236 png_push_crc_skip(png_ptr, png_ptr->push_length);
237 png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
238 return;
239 }
240 else if (chunk_name == png_fdAT)
241 {
242 if (png_ptr->buffer_size < 4)
243 {
244 png_push_save_buffer(png_ptr);
245 return;
246 }
247
248 png_ensure_sequence_number(png_ptr, 4);
249
250 if (!(png_ptr->mode & PNG_HAVE_fcTL))
251 {
252 /* Discard trailing fdATs for frames other than the first */
253 if (png_ptr->num_frames_read < 2)
254 png_error(png_ptr, "out of place fdAT");
255
256 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
257 {
258 png_push_save_buffer(png_ptr);
259 return;
260 }
261
262 png_push_crc_skip(png_ptr, png_ptr->push_length);
263 png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
264 return;
265 }
266
267 else
268 {
269 /* frame data follows */
270 png_ptr->idat_size = png_ptr->push_length - 4;
271 png_ptr->mode |= PNG_HAVE_IDAT;
272 png_ptr->process_mode = PNG_READ_IDAT_MODE;
273
274 return;
275 }
276 }
277
278 else if (chunk_name == png_fcTL)
279 {
280 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
281 {
282 png_push_save_buffer(png_ptr);
283 return;
284 }
285
286 png_read_reset(png_ptr);
287 png_ptr->mode &= ~PNG_HAVE_fcTL;
288
289 png_handle_fcTL(png_ptr, info_ptr, png_ptr->push_length);
290
291 if (!(png_ptr->mode & PNG_HAVE_fcTL))
292 png_error(png_ptr, "missing required fcTL chunk");
293
294 png_read_reinit(png_ptr, info_ptr);
295 png_progressive_read_reset(png_ptr);
296
297 if (png_ptr->frame_info_fn != NULL)
298 (*(png_ptr->frame_info_fn))(png_ptr, png_ptr->num_frames_read);
299
300 png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
301
302 return;
303 }
304
305 else
306 {
307 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
308 {
309 png_push_save_buffer(png_ptr);
310 return;
311 }
312 png_warning(png_ptr, "Skipped (ignored) a chunk "
313 "between APNG chunks");
314 png_push_crc_skip(png_ptr, png_ptr->push_length);
315 png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
316 return;
317 }
318
319 return;
320 }
321 #endif /* PNG_READ_APNG_SUPPORTED */
322
323 if (chunk_name == png_IDAT)
324 {
325 if (png_ptr->mode & PNG_AFTER_IDAT)
326 png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
327
328 /* If we reach an IDAT chunk, this means we have read all of the
329 * header chunks, and we can start reading the image (or if this
330 * is called after the image has been read - we have an error).
331 */
332 if (!(png_ptr->mode & PNG_HAVE_IHDR))
333 png_error(png_ptr, "Missing IHDR before IDAT");
334
335 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
336 !(png_ptr->mode & PNG_HAVE_PLTE))
337 png_error(png_ptr, "Missing PLTE before IDAT");
338
339 png_ptr->mode |= PNG_HAVE_IDAT;
340 png_ptr->process_mode = PNG_READ_IDAT_MODE;
341
342 if (!(png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
343 if (png_ptr->push_length == 0)
344 return;
345
346 if (png_ptr->mode & PNG_AFTER_IDAT)
347 png_benign_error(png_ptr, "Too many IDATs found");
348 }
349
350 if (chunk_name == png_IHDR)
351 {
352 if (png_ptr->push_length != 13)
353 png_error(png_ptr, "Invalid IHDR length");
354
355 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
356 {
357 png_push_save_buffer(png_ptr);
358 return;
359 }
360
361 png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length);
362 }
363
364 else if (chunk_name == png_IEND)
365 {
366 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
367 {
368 png_push_save_buffer(png_ptr);
369 return;
370 }
371
372 png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length);
373
374 png_ptr->process_mode = PNG_READ_DONE_MODE;
375 png_push_have_end(png_ptr, info_ptr);
376 }
377
378 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
379 else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0)
380 {
381 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
382 {
383 png_push_save_buffer(png_ptr);
384 return;
385 }
386
387 png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length, keep);
388
389 if (chunk_name == png_PLTE)
390 png_ptr->mode |= PNG_HAVE_PLTE;
391 }
392 #endif
393
394 else if (chunk_name == png_PLTE)
395 {
396 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
397 {
398 png_push_save_buffer(png_ptr);
399 return;
400 }
401 png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
402 }
403
404 else if (chunk_name == png_IDAT)
405 {
406 #ifdef PNG_READ_APNG_SUPPORTED
407 png_have_info(png_ptr, info_ptr);
408 #endif
409 png_ptr->idat_size = png_ptr->push_length;
410 png_ptr->process_mode = PNG_READ_IDAT_MODE;
411 png_push_have_info(png_ptr, info_ptr);
412 png_ptr->zstream.avail_out =
413 (uInt) PNG_ROWBYTES(png_ptr->pixel_depth,
414 png_ptr->iwidth) + 1;
415 png_ptr->zstream.next_out = png_ptr->row_buf;
416 return;
417 }
418
419 #ifdef PNG_READ_gAMA_SUPPORTED
420 else if (png_ptr->chunk_name == png_gAMA)
421 {
422 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
423 {
424 png_push_save_buffer(png_ptr);
425 return;
426 }
427
428 png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length);
429 }
430
431 #endif
432 #ifdef PNG_READ_sBIT_SUPPORTED
433 else if (png_ptr->chunk_name == png_sBIT)
434 {
435 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
436 {
437 png_push_save_buffer(png_ptr);
438 return;
439 }
440
441 png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length);
442 }
443
444 #endif
445 #ifdef PNG_READ_cHRM_SUPPORTED
446 else if (png_ptr->chunk_name == png_cHRM)
447 {
448 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
449 {
450 png_push_save_buffer(png_ptr);
451 return;
452 }
453
454 png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length);
455 }
456
457 #endif
458 #ifdef PNG_READ_sRGB_SUPPORTED
459 else if (chunk_name == png_sRGB)
460 {
461 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
462 {
463 png_push_save_buffer(png_ptr);
464 return;
465 }
466
467 png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length);
468 }
469
470 #endif
471 #ifdef PNG_READ_iCCP_SUPPORTED
472 else if (png_ptr->chunk_name == png_iCCP)
473 {
474 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
475 {
476 png_push_save_buffer(png_ptr);
477 return;
478 }
479
480 png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length);
481 }
482
483 #endif
484 #ifdef PNG_READ_sPLT_SUPPORTED
485 else if (chunk_name == png_sPLT)
486 {
487 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
488 {
489 png_push_save_buffer(png_ptr);
490 return;
491 }
492
493 png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length);
494 }
495
496 #endif
497 #ifdef PNG_READ_tRNS_SUPPORTED
498 else if (chunk_name == png_tRNS)
499 {
500 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
501 {
502 png_push_save_buffer(png_ptr);
503 return;
504 }
505
506 png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length);
507 }
508
509 #endif
510 #ifdef PNG_READ_bKGD_SUPPORTED
511 else if (chunk_name == png_bKGD)
512 {
513 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
514 {
515 png_push_save_buffer(png_ptr);
516 return;
517 }
518
519 png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length);
520 }
521
522 #endif
523 #ifdef PNG_READ_hIST_SUPPORTED
524 else if (chunk_name == png_hIST)
525 {
526 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
527 {
528 png_push_save_buffer(png_ptr);
529 return;
530 }
531
532 png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length);
533 }
534
535 #endif
536 #ifdef PNG_READ_pHYs_SUPPORTED
537 else if (chunk_name == png_pHYs)
538 {
539 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
540 {
541 png_push_save_buffer(png_ptr);
542 return;
543 }
544
545 png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length);
546 }
547
548 #endif
549 #ifdef PNG_READ_oFFs_SUPPORTED
550 else if (chunk_name == png_oFFs)
551 {
552 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
553 {
554 png_push_save_buffer(png_ptr);
555 return;
556 }
557
558 png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length);
559 }
560 #endif
561
562 #ifdef PNG_READ_pCAL_SUPPORTED
563 else if (chunk_name == png_pCAL)
564 {
565 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
566 {
567 png_push_save_buffer(png_ptr);
568 return;
569 }
570
571 png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length);
572 }
573
574 #endif
575 #ifdef PNG_READ_sCAL_SUPPORTED
576 else if (chunk_name == png_sCAL)
577 {
578 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
579 {
580 png_push_save_buffer(png_ptr);
581 return;
582 }
583
584 png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length);
585 }
586
587 #endif
588 #ifdef PNG_READ_tIME_SUPPORTED
589 else if (chunk_name == png_tIME)
590 {
591 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
592 {
593 png_push_save_buffer(png_ptr);
594 return;
595 }
596
597 png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length);
598 }
599
600 #endif
601 #ifdef PNG_READ_tEXt_SUPPORTED
602 else if (chunk_name == png_tEXt)
603 {
604 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
605 {
606 png_push_save_buffer(png_ptr);
607 return;
608 }
609
610 png_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length);
611 }
612
613 #endif
614 #ifdef PNG_READ_zTXt_SUPPORTED
615 else if (chunk_name == png_zTXt)
616 {
617 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
618 {
619 png_push_save_buffer(png_ptr);
620 return;
621 }
622
623 png_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
624 }
625
626 #endif
627 #ifdef PNG_READ_iTXt_SUPPORTED
628 else if (chunk_name == png_iTXt)
629 {
630 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
631 {
632 png_push_save_buffer(png_ptr);
633 return;
634 }
635
636 png_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
637 }
638 #endif
639
640 #ifdef PNG_READ_APNG_SUPPORTED
641 else if (chunk_name == png_acTL)
642 {
643 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
644 {
645 png_push_save_buffer(png_ptr);
646 return;
647 }
648
649 png_handle_acTL(png_ptr, info_ptr, png_ptr->push_length);
650 }
651
652 else if (chunk_name == png_fcTL)
653 {
654 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
655 {
656 png_push_save_buffer(png_ptr);
657 return;
658 }
659
660 png_handle_fcTL(png_ptr, info_ptr, png_ptr->push_length);
661 }
662
663 #endif /* PNG_READ_APNG_SUPPORTED */
664 else
665 {
666 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
667 {
668 png_push_save_buffer(png_ptr);
669 return;
670 }
671 png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length,
672 PNG_HANDLE_CHUNK_AS_DEFAULT);
673 }
674
675 png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
676 }
677
678 void /* PRIVATE */
679 png_push_crc_skip(png_structrp png_ptr, png_uint_32 skip)
680 {
681 png_ptr->process_mode = PNG_SKIP_MODE;
682 png_ptr->skip_length = skip;
683 }
684
685 void /* PRIVATE */
686 png_push_crc_finish(png_structrp png_ptr)
687 {
688 if (png_ptr->skip_length && png_ptr->save_buffer_size)
689 {
690 png_size_t save_size = png_ptr->save_buffer_size;
691 png_uint_32 skip_length = png_ptr->skip_length;
692
693 /* We want the smaller of 'skip_length' and 'save_buffer_size', but
694 * they are of different types and we don't know which variable has the
695 * fewest bits. Carefully select the smaller and cast it to the type of
696 * the larger - this cannot overflow. Do not cast in the following test
697 * - it will break on either 16 or 64 bit platforms.
698 */
699 if (skip_length < save_size)
700 save_size = (png_size_t)skip_length;
701
702 else
703 skip_length = (png_uint_32)save_size;
704
705 png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
706
707 png_ptr->skip_length -= skip_length;
708 png_ptr->buffer_size -= save_size;
709 png_ptr->save_buffer_size -= save_size;
710 png_ptr->save_buffer_ptr += save_size;
711 }
712 if (png_ptr->skip_length && png_ptr->current_buffer_size)
713 {
714 png_size_t save_size = png_ptr->current_buffer_size;
715 png_uint_32 skip_length = png_ptr->skip_length;
716
717 /* We want the smaller of 'skip_length' and 'current_buffer_size', here,
718 * the same problem exists as above and the same solution.
719 */
720 if (skip_length < save_size)
721 save_size = (png_size_t)skip_length;
722
723 else
724 skip_length = (png_uint_32)save_size;
725
726 png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
727
728 png_ptr->skip_length -= skip_length;
729 png_ptr->buffer_size -= save_size;
730 png_ptr->current_buffer_size -= save_size;
731 png_ptr->current_buffer_ptr += save_size;
732 }
733 if (!png_ptr->skip_length)
734 {
735 if (png_ptr->buffer_size < 4)
736 {
737 png_push_save_buffer(png_ptr);
738 return;
739 }
740
741 png_crc_finish(png_ptr, 0);
742 png_ptr->process_mode = PNG_READ_CHUNK_MODE;
743 }
744 }
745
746 void PNGCBAPI
747 png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
748 {
749 png_bytep ptr;
750
751 if (png_ptr == NULL)
752 return;
753
754 ptr = buffer;
755 if (png_ptr->save_buffer_size)
756 {
757 png_size_t save_size;
758
759 if (length < png_ptr->save_buffer_size)
760 save_size = length;
761
762 else
763 save_size = png_ptr->save_buffer_size;
764
765 memcpy(ptr, png_ptr->save_buffer_ptr, save_size);
766 length -= save_size;
767 ptr += save_size;
768 png_ptr->buffer_size -= save_size;
769 png_ptr->save_buffer_size -= save_size;
770 png_ptr->save_buffer_ptr += save_size;
771 }
772 if (length && png_ptr->current_buffer_size)
773 {
774 png_size_t save_size;
775
776 if (length < png_ptr->current_buffer_size)
777 save_size = length;
778
779 else
780 save_size = png_ptr->current_buffer_size;
781
782 memcpy(ptr, png_ptr->current_buffer_ptr, save_size);
783 png_ptr->buffer_size -= save_size;
784 png_ptr->current_buffer_size -= save_size;
785 png_ptr->current_buffer_ptr += save_size;
786 }
787 }
788
789 void /* PRIVATE */
790 png_push_save_buffer(png_structrp png_ptr)
791 {
792 if (png_ptr->save_buffer_size)
793 {
794 if (png_ptr->save_buffer_ptr != png_ptr->save_buffer)
795 {
796 png_size_t i, istop;
797 png_bytep sp;
798 png_bytep dp;
799
800 istop = png_ptr->save_buffer_size;
801 for (i = 0, sp = png_ptr->save_buffer_ptr, dp = png_ptr->save_buffer;
802 i < istop; i++, sp++, dp++)
803 {
804 *dp = *sp;
805 }
806 }
807 }
808 if (png_ptr->save_buffer_size + png_ptr->current_buffer_size >
809 png_ptr->save_buffer_max)
810 {
811 png_size_t new_max;
812 png_bytep old_buffer;
813
814 if (png_ptr->save_buffer_size > PNG_SIZE_MAX -
815 (png_ptr->current_buffer_size + 256))
816 {
817 png_error(png_ptr, "Potential overflow of save_buffer");
818 }
819
820 new_max = png_ptr->save_buffer_size + png_ptr->current_buffer_size + 256;
821 old_buffer = png_ptr->save_buffer;
822 png_ptr->save_buffer = (png_bytep)png_malloc_warn(png_ptr,
823 (png_size_t)new_max);
824
825 if (png_ptr->save_buffer == NULL)
826 {
827 png_free(png_ptr, old_buffer);
828 png_error(png_ptr, "Insufficient memory for save_buffer");
829 }
830
831 memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size);
832 png_free(png_ptr, old_buffer);
833 png_ptr->save_buffer_max = new_max;
834 }
835 if (png_ptr->current_buffer_size)
836 {
837 memcpy(png_ptr->save_buffer + png_ptr->save_buffer_size,
838 png_ptr->current_buffer_ptr, png_ptr->current_buffer_size);
839 png_ptr->save_buffer_size += png_ptr->current_buffer_size;
840 png_ptr->current_buffer_size = 0;
841 }
842 png_ptr->save_buffer_ptr = png_ptr->save_buffer;
843 png_ptr->buffer_size = 0;
844 }
845
846 void /* PRIVATE */
847 png_push_restore_buffer(png_structrp png_ptr, png_bytep buffer,
848 png_size_t buffer_length)
849 {
850 png_ptr->current_buffer = buffer;
851 png_ptr->current_buffer_size = buffer_length;
852 png_ptr->buffer_size = buffer_length + png_ptr->save_buffer_size;
853 png_ptr->current_buffer_ptr = png_ptr->current_buffer;
854 }
855
856 void /* PRIVATE */
857 png_push_read_IDAT(png_structrp png_ptr)
858 {
859 if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
860 {
861 png_byte chunk_length[4];
862 png_byte chunk_tag[4];
863
864 /* TODO: this code can be commoned up with the same code in push_read */
865 #ifdef PNG_READ_APNG_SUPPORTED
866 if (png_ptr->buffer_size < 12)
867 #else
868 if (png_ptr->buffer_size < 8)
869 #endif
870 {
871 png_push_save_buffer(png_ptr);
872 return;
873 }
874
875 png_push_fill_buffer(png_ptr, chunk_length, 4);
876 png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
877 png_reset_crc(png_ptr);
878 png_crc_read(png_ptr, chunk_tag, 4);
879 png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag);
880 png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
881
882 #ifdef PNG_READ_APNG_SUPPORTED
883 if (png_ptr->chunk_name != png_fdAT && png_ptr->num_frames_read > 0)
884 {
885 if (png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED)
886 {
887 png_ptr->process_mode = PNG_READ_CHUNK_MODE;
888 if (png_ptr->frame_end_fn != NULL)
889 (*(png_ptr->frame_end_fn))(png_ptr, png_ptr->num_frames_read);
890 png_ptr->num_frames_read++;
891 return;
892 }
893 else
894 {
895 if (png_ptr->chunk_name == png_IEND)
896 png_error(png_ptr, "Not enough image data");
897 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
898 {
899 png_push_save_buffer(png_ptr);
900 return;
901 }
902 png_warning(png_ptr, "Skipping (ignoring) a chunk between "
903 "APNG chunks");
904 png_crc_finish(png_ptr, png_ptr->push_length);
905 png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
906 return;
907 }
908 }
909 else
910 #endif
911 #ifdef PNG_READ_APNG_SUPPORTED
912 if (png_ptr->chunk_name != png_IDAT && png_ptr->num_frames_read == 0)
913 #else
914 if (png_ptr->chunk_name != png_IDAT)
915 #endif
916 {
917 png_ptr->process_mode = PNG_READ_CHUNK_MODE;
918
919 if (!(png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED))
920 png_error(png_ptr, "Not enough compressed data");
921
922 #ifdef PNG_READ_APNG_SUPPORTED
923 if (png_ptr->frame_end_fn != NULL)
924 (*(png_ptr->frame_end_fn))(png_ptr, png_ptr->num_frames_read);
925 png_ptr->num_frames_read++;
926 #endif
927
928 return;
929 }
930
931 png_ptr->idat_size = png_ptr->push_length;
932
933 #ifdef PNG_READ_APNG_SUPPORTED
934 if (png_ptr->num_frames_read > 0)
935 {
936 png_ensure_sequence_number(png_ptr, 4);
937 png_ptr->idat_size -= 4;
938 }
939 #endif
940 }
941
942 if (png_ptr->idat_size && png_ptr->save_buffer_size)
943 {
944 png_size_t save_size = png_ptr->save_buffer_size;
945 png_uint_32 idat_size = png_ptr->idat_size;
946
947 /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
948 * are of different types and we don't know which variable has the fewest
949 * bits. Carefully select the smaller and cast it to the type of the
950 * larger - this cannot overflow. Do not cast in the following test - it
951 * will break on either 16 or 64 bit platforms.
952 */
953 if (idat_size < save_size)
954 save_size = (png_size_t)idat_size;
955
956 else
957 idat_size = (png_uint_32)save_size;
958
959 png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
960
961 png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size);
962
963 png_ptr->idat_size -= idat_size;
964 png_ptr->buffer_size -= save_size;
965 png_ptr->save_buffer_size -= save_size;
966 png_ptr->save_buffer_ptr += save_size;
967 }
968
969 if (png_ptr->idat_size && png_ptr->current_buffer_size)
970 {
971 png_size_t save_size = png_ptr->current_buffer_size;
972 png_uint_32 idat_size = png_ptr->idat_size;
973
974 /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
975 * are of different types and we don't know which variable has the fewest
976 * bits. Carefully select the smaller and cast it to the type of the
977 * larger - this cannot overflow.
978 */
979 if (idat_size < save_size)
980 save_size = (png_size_t)idat_size;
981
982 else
983 idat_size = (png_uint_32)save_size;
984
985 png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
986
987 png_process_IDAT_data(png_ptr, png_ptr->current_buffer_ptr, save_size);
988
989 png_ptr->idat_size -= idat_size;
990 png_ptr->buffer_size -= save_size;
991 png_ptr->current_buffer_size -= save_size;
992 png_ptr->current_buffer_ptr += save_size;
993 }
994 if (!png_ptr->idat_size)
995 {
996 if (png_ptr->buffer_size < 4)
997 {
998 png_push_save_buffer(png_ptr);
999 return;
1000 }
1001
1002 png_crc_finish(png_ptr, 0);
1003 png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
1004 png_ptr->mode |= PNG_AFTER_IDAT;
1005 png_ptr->zowner = 0;
1006 }
1007 }
1008
1009 void /* PRIVATE */
1010 png_process_IDAT_data(png_structrp png_ptr, png_bytep buffer,
1011 png_size_t buffer_length)
1012 {
1013 /* The caller checks for a non-zero buffer length. */
1014 if (!(buffer_length > 0) || buffer == NULL)
1015 png_error(png_ptr, "No IDAT data (internal error)");
1016
1017 #ifdef PNG_READ_APNG_SUPPORTED
1018 /* If the app is not APNG-aware, decode only the first frame */
1019 if (!(png_ptr->apng_flags & PNG_APNG_APP) && png_ptr->num_frames_read > 0)
1020 {
1021 png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
1022 return;
1023 }
1024 #endif
1025
1026 /* This routine must process all the data it has been given
1027 * before returning, calling the row callback as required to
1028 * handle the uncompressed results.
1029 */
1030 png_ptr->zstream.next_in = buffer;
1031 /* TODO: WARNING: TRUNCATION ERROR: DANGER WILL ROBINSON: */
1032 png_ptr->zstream.avail_in = (uInt)buffer_length;
1033
1034 /* Keep going until the decompressed data is all processed
1035 * or the stream marked as finished.
1036 */
1037 while (png_ptr->zstream.avail_in > 0 &&
1038 !(png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED))
1039 {
1040 int ret;
1041
1042 /* We have data for zlib, but we must check that zlib
1043 * has someplace to put the results. It doesn't matter
1044 * if we don't expect any results -- it may be the input
1045 * data is just the LZ end code.
1046 */
1047 if (!(png_ptr->zstream.avail_out > 0))
1048 {
1049 /* TODO: WARNING: TRUNCATION ERROR: DANGER WILL ROBINSON: */
1050 png_ptr->zstream.avail_out = (uInt)(PNG_ROWBYTES(png_ptr->pixel_depth,
1051 png_ptr->iwidth) + 1);
1052
1053 png_ptr->zstream.next_out = png_ptr->row_buf;
1054 }
1055
1056 /* Using Z_SYNC_FLUSH here means that an unterminated
1057 * LZ stream (a stream with a missing end code) can still
1058 * be handled, otherwise (Z_NO_FLUSH) a future zlib
1059 * implementation might defer output and therefore
1060 * change the current behavior (see comments in inflate.c
1061 * for why this doesn't happen at present with zlib 1.2.5).
1062 */
1063 ret = inflate(&png_ptr->zstream, Z_SYNC_FLUSH);
1064
1065 /* Check for any failure before proceeding. */
1066 if (ret != Z_OK && ret != Z_STREAM_END)
1067 {
1068 /* Terminate the decompression. */
1069 png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
1070 png_ptr->zowner = 0;
1071
1072 /* This may be a truncated stream (missing or
1073 * damaged end code). Treat that as a warning.
1074 */
1075 if (png_ptr->row_number >= png_ptr->num_rows ||
1076 png_ptr->pass > 6)
1077 png_warning(png_ptr, "Truncated compressed data in IDAT");
1078
1079 else
1080 png_error(png_ptr, "Decompression error in IDAT");
1081
1082 /* Skip the check on unprocessed input */
1083 return;
1084 }
1085
1086 /* Did inflate output any data? */
1087 if (png_ptr->zstream.next_out != png_ptr->row_buf)
1088 {
1089 /* Is this unexpected data after the last row?
1090 * If it is, artificially terminate the LZ output
1091 * here.
1092 */
1093 if (png_ptr->row_number >= png_ptr->num_rows ||
1094 png_ptr->pass > 6)
1095 {
1096 /* Extra data. */
1097 png_warning(png_ptr, "Extra compressed data in IDAT");
1098 png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
1099 png_ptr->zowner = 0;
1100
1101 /* Do no more processing; skip the unprocessed
1102 * input check below.
1103 */
1104 return;
1105 }
1106
1107 /* Do we have a complete row? */
1108 if (png_ptr->zstream.avail_out == 0)
1109 png_push_process_row(png_ptr);
1110 }
1111
1112 /* And check for the end of the stream. */
1113 if (ret == Z_STREAM_END)
1114 png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
1115 }
1116
1117 /* All the data should have been processed, if anything
1118 * is left at this point we have bytes of IDAT data
1119 * after the zlib end code.
1120 */
1121 if (png_ptr->zstream.avail_in > 0)
1122 png_warning(png_ptr, "Extra compression data in IDAT");
1123 }
1124
1125 void /* PRIVATE */
1126 png_push_process_row(png_structrp png_ptr)
1127 {
1128 /* 1.5.6: row_info moved out of png_struct to a local here. */
1129 png_row_info row_info;
1130
1131 row_info.width = png_ptr->iwidth; /* NOTE: width of current interlaced row */
1132 row_info.color_type = png_ptr->color_type;
1133 row_info.bit_depth = png_ptr->bit_depth;
1134 row_info.channels = png_ptr->channels;
1135 row_info.pixel_depth = png_ptr->pixel_depth;
1136 row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
1137
1138 if (png_ptr->row_buf[0] > PNG_FILTER_VALUE_NONE)
1139 {
1140 if (png_ptr->row_buf[0] < PNG_FILTER_VALUE_LAST)
1141 png_read_filter_row(png_ptr, &row_info, png_ptr->row_buf + 1,
1142 png_ptr->prev_row + 1, png_ptr->row_buf[0]);
1143 else
1144 png_error(png_ptr, "bad adaptive filter value");
1145 }
1146
1147 /* libpng 1.5.6: the following line was copying png_ptr->rowbytes before
1148 * 1.5.6, while the buffer really is this big in current versions of libpng
1149 * it may not be in the future, so this was changed just to copy the
1150 * interlaced row count:
1151 */
1152 memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1);
1153
1154 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1155 if (png_ptr->transformations)
1156 png_do_read_transformations(png_ptr, &row_info);
1157 #endif
1158
1159 /* The transformed pixel depth should match the depth now in row_info. */
1160 if (png_ptr->transformed_pixel_depth == 0)
1161 {
1162 png_ptr->transformed_pixel_depth = row_info.pixel_depth;
1163 if (row_info.pixel_depth > png_ptr->maximum_pixel_depth)
1164 png_error(png_ptr, "progressive row overflow");
1165 }
1166
1167 else if (png_ptr->transformed_pixel_depth != row_info.pixel_depth)
1168 png_error(png_ptr, "internal progressive row size calculation error");
1169
1170
1171 #ifdef PNG_READ_INTERLACING_SUPPORTED
1172 /* Blow up interlaced rows to full size */
1173 if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
1174 {
1175 if (png_ptr->pass < 6)
1176 png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass,
1177 png_ptr->transformations);
1178
1179 switch (png_ptr->pass)
1180 {
1181 case 0:
1182 {
1183 int i;
1184 for (i = 0; i < 8 && png_ptr->pass == 0; i++)
1185 {
1186 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1187 png_read_push_finish_row(png_ptr); /* Updates png_ptr->pass */
1188 }
1189
1190 if (png_ptr->pass == 2) /* Pass 1 might be empty */
1191 {
1192 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
1193 {
1194 png_push_have_row(png_ptr, NULL);
1195 png_read_push_finish_row(png_ptr);
1196 }
1197 }
1198
1199 if (png_ptr->pass == 4 && png_ptr->height <= 4)
1200 {
1201 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
1202 {
1203 png_push_have_row(png_ptr, NULL);
1204 png_read_push_finish_row(png_ptr);
1205 }
1206 }
1207
1208 if (png_ptr->pass == 6 && png_ptr->height <= 4)
1209 {
1210 png_push_have_row(png_ptr, NULL);
1211 png_read_push_finish_row(png_ptr);
1212 }
1213
1214 break;
1215 }
1216
1217 case 1:
1218 {
1219 int i;
1220 for (i = 0; i < 8 && png_ptr->pass == 1; i++)
1221 {
1222 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1223 png_read_push_finish_row(png_ptr);
1224 }
1225
1226 if (png_ptr->pass == 2) /* Skip top 4 generated rows */
1227 {
1228 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
1229 {
1230 png_push_have_row(png_ptr, NULL);
1231 png_read_push_finish_row(png_ptr);
1232 }
1233 }
1234
1235 break;
1236 }
1237
1238 case 2:
1239 {
1240 int i;
1241
1242 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
1243 {
1244 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1245 png_read_push_finish_row(png_ptr);
1246 }
1247
1248 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
1249 {
1250 png_push_have_row(png_ptr, NULL);
1251 png_read_push_finish_row(png_ptr);
1252 }
1253
1254 if (png_ptr->pass == 4) /* Pass 3 might be empty */
1255 {
1256 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
1257 {
1258 png_push_have_row(png_ptr, NULL);
1259 png_read_push_finish_row(png_ptr);
1260 }
1261 }
1262
1263 break;
1264 }
1265
1266 case 3:
1267 {
1268 int i;
1269
1270 for (i = 0; i < 4 && png_ptr->pass == 3; i++)
1271 {
1272 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1273 png_read_push_finish_row(png_ptr);
1274 }
1275
1276 if (png_ptr->pass == 4) /* Skip top two generated rows */
1277 {
1278 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
1279 {
1280 png_push_have_row(png_ptr, NULL);
1281 png_read_push_finish_row(png_ptr);
1282 }
1283 }
1284
1285 break;
1286 }
1287
1288 case 4:
1289 {
1290 int i;
1291
1292 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
1293 {
1294 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1295 png_read_push_finish_row(png_ptr);
1296 }
1297
1298 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
1299 {
1300 png_push_have_row(png_ptr, NULL);
1301 png_read_push_finish_row(png_ptr);
1302 }
1303
1304 if (png_ptr->pass == 6) /* Pass 5 might be empty */
1305 {
1306 png_push_have_row(png_ptr, NULL);
1307 png_read_push_finish_row(png_ptr);
1308 }
1309
1310 break;
1311 }
1312
1313 case 5:
1314 {
1315 int i;
1316
1317 for (i = 0; i < 2 && png_ptr->pass == 5; i++)
1318 {
1319 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1320 png_read_push_finish_row(png_ptr);
1321 }
1322
1323 if (png_ptr->pass == 6) /* Skip top generated row */
1324 {
1325 png_push_have_row(png_ptr, NULL);
1326 png_read_push_finish_row(png_ptr);
1327 }
1328
1329 break;
1330 }
1331
1332 default:
1333 case 6:
1334 {
1335 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1336 png_read_push_finish_row(png_ptr);
1337
1338 if (png_ptr->pass != 6)
1339 break;
1340
1341 png_push_have_row(png_ptr, NULL);
1342 png_read_push_finish_row(png_ptr);
1343 }
1344 }
1345 }
1346 else
1347 #endif
1348 {
1349 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1350 png_read_push_finish_row(png_ptr);
1351 }
1352 }
1353
1354 void /* PRIVATE */
1355 png_read_push_finish_row(png_structrp png_ptr)
1356 {
1357 #ifdef PNG_READ_INTERLACING_SUPPORTED
1358 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
1359
1360 /* Start of interlace block */
1361 static PNG_CONST png_byte png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
1362
1363 /* Offset to next interlace block */
1364 static PNG_CONST png_byte png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
1365
1366 /* Start of interlace block in the y direction */
1367 static PNG_CONST png_byte png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
1368
1369 /* Offset to next interlace block in the y direction */
1370 static PNG_CONST png_byte png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
1371
1372 /* Height of interlace block. This is not currently used - if you need
1373 * it, uncomment it here and in png.h
1374 static PNG_CONST png_byte png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
1375 */
1376 #endif
1377
1378 png_ptr->row_number++;
1379 if (png_ptr->row_number < png_ptr->num_rows)
1380 return;
1381
1382 #ifdef PNG_READ_INTERLACING_SUPPORTED
1383 if (png_ptr->interlaced)
1384 {
1385 png_ptr->row_number = 0;
1386 memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
1387
1388 do
1389 {
1390 png_ptr->pass++;
1391 if ((png_ptr->pass == 1 && png_ptr->width < 5) ||
1392 (png_ptr->pass == 3 && png_ptr->width < 3) ||
1393 (png_ptr->pass == 5 && png_ptr->width < 2))
1394 png_ptr->pass++;
1395
1396 if (png_ptr->pass > 7)
1397 png_ptr->pass--;
1398
1399 if (png_ptr->pass >= 7)
1400 break;
1401
1402 png_ptr->iwidth = (png_ptr->width +
1403 png_pass_inc[png_ptr->pass] - 1 -
1404 png_pass_start[png_ptr->pass]) /
1405 png_pass_inc[png_ptr->pass];
1406
1407 if (png_ptr->transformations & PNG_INTERLACE)
1408 break;
1409
1410 png_ptr->num_rows = (png_ptr->height +
1411 png_pass_yinc[png_ptr->pass] - 1 -
1412 png_pass_ystart[png_ptr->pass]) /
1413 png_pass_yinc[png_ptr->pass];
1414
1415 } while (png_ptr->iwidth == 0 || png_ptr->num_rows == 0);
1416 }
1417 #endif /* PNG_READ_INTERLACING_SUPPORTED */
1418 }
1419
1420 void /* PRIVATE */
1421 png_push_have_info(png_structrp png_ptr, png_inforp info_ptr)
1422 {
1423 if (png_ptr->info_fn != NULL)
1424 (*(png_ptr->info_fn))(png_ptr, info_ptr);
1425 }
1426
1427 void /* PRIVATE */
1428 png_push_have_end(png_structrp png_ptr, png_inforp info_ptr)
1429 {
1430 if (png_ptr->end_fn != NULL)
1431 (*(png_ptr->end_fn))(png_ptr, info_ptr);
1432 }
1433
1434 void /* PRIVATE */
1435 png_push_have_row(png_structrp png_ptr, png_bytep row)
1436 {
1437 if (png_ptr->row_fn != NULL)
1438 (*(png_ptr->row_fn))(png_ptr, row, png_ptr->row_number,
1439 (int)png_ptr->pass);
1440 }
1441
1442 #ifdef PNG_READ_INTERLACING_SUPPORTED
1443 void PNGAPI
1444 png_progressive_combine_row(png_const_structrp png_ptr, png_bytep old_row,
1445 png_const_bytep new_row)
1446 {
1447 if (png_ptr == NULL)
1448 return;
1449
1450 /* new_row is a flag here - if it is NULL then the app callback was called
1451 * from an empty row (see the calls to png_struct::row_fn below), otherwise
1452 * it must be png_ptr->row_buf+1
1453 */
1454 if (new_row != NULL)
1455 png_combine_row(png_ptr, old_row, 1/*display*/);
1456 }
1457 #endif /* PNG_READ_INTERLACING_SUPPORTED */
1458
1459 void PNGAPI
1460 png_set_progressive_read_fn(png_structrp png_ptr, png_voidp progressive_ptr,
1461 png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,
1462 png_progressive_end_ptr end_fn)
1463 {
1464 if (png_ptr == NULL)
1465 return;
1466
1467 png_ptr->info_fn = info_fn;
1468 png_ptr->row_fn = row_fn;
1469 png_ptr->end_fn = end_fn;
1470
1471 png_set_read_fn(png_ptr, progressive_ptr, png_push_fill_buffer);
1472 }
1473
1474 #ifdef PNG_READ_APNG_SUPPORTED
1475 void PNGAPI
1476 png_set_progressive_frame_fn(png_structp png_ptr,
1477 png_progressive_frame_ptr frame_info_fn,
1478 png_progressive_frame_ptr frame_end_fn)
1479 {
1480 png_ptr->frame_info_fn = frame_info_fn;
1481 png_ptr->frame_end_fn = frame_end_fn;
1482 png_ptr->apng_flags |= PNG_APNG_APP;
1483 }
1484 #endif
1485
1486 png_voidp PNGAPI
1487 png_get_progressive_ptr(png_const_structrp png_ptr)
1488 {
1489 if (png_ptr == NULL)
1490 return (NULL);
1491
1492 return png_ptr->io_ptr;
1493 }
1494 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */

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