[DEVENUM]
[reactos.git] / reactos / dll / 3rdparty / libpng / pngpread.c
1
2 /* pngpread.c - read a png file in push mode
3 *
4 * Last changed in libpng 1.5.11 [June 14, 2012]
5 * Copyright (c) 1998-2012 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_structp png_ptr, png_infop 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_structp 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_structp 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_structp png_ptr, png_infop 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_structp png_ptr, png_infop info_ptr)
153 {
154 png_size_t num_checked = png_ptr->sig_bytes,
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
176 else
177 {
178 if (png_ptr->sig_bytes >= 8)
179 {
180 png_ptr->process_mode = PNG_READ_CHUNK_MODE;
181 }
182 }
183 }
184
185 void /* PRIVATE */
186 png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
187 {
188 png_uint_32 chunk_name;
189
190 /* First we make sure we have enough data for the 4 byte chunk name
191 * and the 4 byte chunk length before proceeding with decoding the
192 * chunk data. To fully decode each of these chunks, we also make
193 * sure we have enough data in the buffer for the 4 byte CRC at the
194 * end of every chunk (except IDAT, which is handled separately).
195 */
196 if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
197 {
198 png_byte chunk_length[4];
199 png_byte chunk_tag[4];
200
201 if (png_ptr->buffer_size < 8)
202 {
203 png_push_save_buffer(png_ptr);
204 return;
205 }
206
207 png_push_fill_buffer(png_ptr, chunk_length, 4);
208 png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
209 png_reset_crc(png_ptr);
210 png_crc_read(png_ptr, chunk_tag, 4);
211 png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag);
212 png_check_chunk_name(png_ptr, png_ptr->chunk_name);
213 png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
214 }
215
216 chunk_name = png_ptr->chunk_name;
217
218 if (chunk_name == png_IDAT)
219 {
220 /* This is here above the if/else case statement below because if the
221 * unknown handling marks 'IDAT' as unknown then the IDAT handling case is
222 * completely skipped.
223 *
224 * TODO: there must be a better way of doing this.
225 */
226 if (png_ptr->mode & PNG_AFTER_IDAT)
227 png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
228 }
229
230 if (chunk_name == png_IHDR)
231 {
232 if (png_ptr->push_length != 13)
233 png_error(png_ptr, "Invalid IHDR length");
234
235 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
236 {
237 png_push_save_buffer(png_ptr);
238 return;
239 }
240
241 png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length);
242 }
243
244 else if (chunk_name == png_IEND)
245 {
246 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
247 {
248 png_push_save_buffer(png_ptr);
249 return;
250 }
251
252 png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length);
253
254 png_ptr->process_mode = PNG_READ_DONE_MODE;
255 png_push_have_end(png_ptr, info_ptr);
256 }
257
258 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
259 else if (png_chunk_unknown_handling(png_ptr, chunk_name))
260 {
261 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
262 {
263 png_push_save_buffer(png_ptr);
264 return;
265 }
266
267 if (chunk_name == png_IDAT)
268 png_ptr->mode |= PNG_HAVE_IDAT;
269
270 png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length);
271
272 if (chunk_name == png_PLTE)
273 png_ptr->mode |= PNG_HAVE_PLTE;
274
275 else if (chunk_name == png_IDAT)
276 {
277 if (!(png_ptr->mode & PNG_HAVE_IHDR))
278 png_error(png_ptr, "Missing IHDR before IDAT");
279
280 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
281 !(png_ptr->mode & PNG_HAVE_PLTE))
282 png_error(png_ptr, "Missing PLTE before IDAT");
283 }
284 }
285 #endif
286
287 else if (chunk_name == png_PLTE)
288 {
289 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
290 {
291 png_push_save_buffer(png_ptr);
292 return;
293 }
294 png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
295 }
296
297 else if (chunk_name == png_IDAT)
298 {
299 /* If we reach an IDAT chunk, this means we have read all of the
300 * header chunks, and we can start reading the image (or if this
301 * is called after the image has been read - we have an error).
302 */
303
304 if (!(png_ptr->mode & PNG_HAVE_IHDR))
305 png_error(png_ptr, "Missing IHDR before IDAT");
306
307 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
308 !(png_ptr->mode & PNG_HAVE_PLTE))
309 png_error(png_ptr, "Missing PLTE before IDAT");
310
311 if (png_ptr->mode & PNG_HAVE_IDAT)
312 {
313 if (!(png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
314 if (png_ptr->push_length == 0)
315 return;
316
317 if (png_ptr->mode & PNG_AFTER_IDAT)
318 png_benign_error(png_ptr, "Too many IDATs found");
319 }
320
321 png_ptr->idat_size = png_ptr->push_length;
322 png_ptr->mode |= PNG_HAVE_IDAT;
323 png_ptr->process_mode = PNG_READ_IDAT_MODE;
324 png_push_have_info(png_ptr, info_ptr);
325 png_ptr->zstream.avail_out =
326 (uInt) PNG_ROWBYTES(png_ptr->pixel_depth,
327 png_ptr->iwidth) + 1;
328 png_ptr->zstream.next_out = png_ptr->row_buf;
329 return;
330 }
331
332 #ifdef PNG_READ_gAMA_SUPPORTED
333 else if (png_ptr->chunk_name == png_gAMA)
334 {
335 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
336 {
337 png_push_save_buffer(png_ptr);
338 return;
339 }
340
341 png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length);
342 }
343
344 #endif
345 #ifdef PNG_READ_sBIT_SUPPORTED
346 else if (png_ptr->chunk_name == png_sBIT)
347 {
348 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
349 {
350 png_push_save_buffer(png_ptr);
351 return;
352 }
353
354 png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length);
355 }
356
357 #endif
358 #ifdef PNG_READ_cHRM_SUPPORTED
359 else if (png_ptr->chunk_name == png_cHRM)
360 {
361 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
362 {
363 png_push_save_buffer(png_ptr);
364 return;
365 }
366
367 png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length);
368 }
369
370 #endif
371 #ifdef PNG_READ_sRGB_SUPPORTED
372 else if (chunk_name == png_sRGB)
373 {
374 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
375 {
376 png_push_save_buffer(png_ptr);
377 return;
378 }
379
380 png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length);
381 }
382
383 #endif
384 #ifdef PNG_READ_iCCP_SUPPORTED
385 else if (png_ptr->chunk_name == png_iCCP)
386 {
387 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
388 {
389 png_push_save_buffer(png_ptr);
390 return;
391 }
392
393 png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length);
394 }
395
396 #endif
397 #ifdef PNG_READ_sPLT_SUPPORTED
398 else if (chunk_name == png_sPLT)
399 {
400 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
401 {
402 png_push_save_buffer(png_ptr);
403 return;
404 }
405
406 png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length);
407 }
408
409 #endif
410 #ifdef PNG_READ_tRNS_SUPPORTED
411 else if (chunk_name == png_tRNS)
412 {
413 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
414 {
415 png_push_save_buffer(png_ptr);
416 return;
417 }
418
419 png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length);
420 }
421
422 #endif
423 #ifdef PNG_READ_bKGD_SUPPORTED
424 else if (chunk_name == png_bKGD)
425 {
426 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
427 {
428 png_push_save_buffer(png_ptr);
429 return;
430 }
431
432 png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length);
433 }
434
435 #endif
436 #ifdef PNG_READ_hIST_SUPPORTED
437 else if (chunk_name == png_hIST)
438 {
439 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
440 {
441 png_push_save_buffer(png_ptr);
442 return;
443 }
444
445 png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length);
446 }
447
448 #endif
449 #ifdef PNG_READ_pHYs_SUPPORTED
450 else if (chunk_name == png_pHYs)
451 {
452 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
453 {
454 png_push_save_buffer(png_ptr);
455 return;
456 }
457
458 png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length);
459 }
460
461 #endif
462 #ifdef PNG_READ_oFFs_SUPPORTED
463 else if (chunk_name == png_oFFs)
464 {
465 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
466 {
467 png_push_save_buffer(png_ptr);
468 return;
469 }
470
471 png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length);
472 }
473 #endif
474
475 #ifdef PNG_READ_pCAL_SUPPORTED
476 else if (chunk_name == png_pCAL)
477 {
478 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
479 {
480 png_push_save_buffer(png_ptr);
481 return;
482 }
483
484 png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length);
485 }
486
487 #endif
488 #ifdef PNG_READ_sCAL_SUPPORTED
489 else if (chunk_name == png_sCAL)
490 {
491 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
492 {
493 png_push_save_buffer(png_ptr);
494 return;
495 }
496
497 png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length);
498 }
499
500 #endif
501 #ifdef PNG_READ_tIME_SUPPORTED
502 else if (chunk_name == png_tIME)
503 {
504 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
505 {
506 png_push_save_buffer(png_ptr);
507 return;
508 }
509
510 png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length);
511 }
512
513 #endif
514 #ifdef PNG_READ_tEXt_SUPPORTED
515 else if (chunk_name == png_tEXt)
516 {
517 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
518 {
519 png_push_save_buffer(png_ptr);
520 return;
521 }
522
523 png_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length);
524 }
525
526 #endif
527 #ifdef PNG_READ_zTXt_SUPPORTED
528 else if (chunk_name == png_zTXt)
529 {
530 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
531 {
532 png_push_save_buffer(png_ptr);
533 return;
534 }
535
536 png_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
537 }
538
539 #endif
540 #ifdef PNG_READ_iTXt_SUPPORTED
541 else if (chunk_name == png_iTXt)
542 {
543 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
544 {
545 png_push_save_buffer(png_ptr);
546 return;
547 }
548
549 png_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
550 }
551
552 #endif
553
554 else
555 {
556 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
557 {
558 png_push_save_buffer(png_ptr);
559 return;
560 }
561 png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length);
562 }
563
564 png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
565 }
566
567 void /* PRIVATE */
568 png_push_crc_skip(png_structp png_ptr, png_uint_32 skip)
569 {
570 png_ptr->process_mode = PNG_SKIP_MODE;
571 png_ptr->skip_length = skip;
572 }
573
574 void /* PRIVATE */
575 png_push_crc_finish(png_structp png_ptr)
576 {
577 if (png_ptr->skip_length && png_ptr->save_buffer_size)
578 {
579 png_size_t save_size = png_ptr->save_buffer_size;
580 png_uint_32 skip_length = png_ptr->skip_length;
581
582 /* We want the smaller of 'skip_length' and 'save_buffer_size', but
583 * they are of different types and we don't know which variable has the
584 * fewest bits. Carefully select the smaller and cast it to the type of
585 * the larger - this cannot overflow. Do not cast in the following test
586 * - it will break on either 16 or 64 bit platforms.
587 */
588 if (skip_length < save_size)
589 save_size = (png_size_t)skip_length;
590
591 else
592 skip_length = (png_uint_32)save_size;
593
594 png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
595
596 png_ptr->skip_length -= skip_length;
597 png_ptr->buffer_size -= save_size;
598 png_ptr->save_buffer_size -= save_size;
599 png_ptr->save_buffer_ptr += save_size;
600 }
601
602 if (png_ptr->skip_length && png_ptr->current_buffer_size)
603 {
604 png_size_t save_size = png_ptr->current_buffer_size;
605 png_uint_32 skip_length = png_ptr->skip_length;
606
607 /* We want the smaller of 'skip_length' and 'current_buffer_size', here,
608 * the same problem exists as above and the same solution.
609 */
610 if (skip_length < save_size)
611 save_size = (png_size_t)skip_length;
612
613 else
614 skip_length = (png_uint_32)save_size;
615
616 png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
617
618 png_ptr->skip_length -= skip_length;
619 png_ptr->buffer_size -= save_size;
620 png_ptr->current_buffer_size -= save_size;
621 png_ptr->current_buffer_ptr += save_size;
622 }
623
624 if (!png_ptr->skip_length)
625 {
626 if (png_ptr->buffer_size < 4)
627 {
628 png_push_save_buffer(png_ptr);
629 return;
630 }
631
632 png_crc_finish(png_ptr, 0);
633 png_ptr->process_mode = PNG_READ_CHUNK_MODE;
634 }
635 }
636
637 void PNGCBAPI
638 png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
639 {
640 png_bytep ptr;
641
642 if (png_ptr == NULL)
643 return;
644
645 ptr = buffer;
646
647 if (png_ptr->save_buffer_size)
648 {
649 png_size_t save_size;
650
651 if (length < png_ptr->save_buffer_size)
652 save_size = length;
653
654 else
655 save_size = png_ptr->save_buffer_size;
656
657 png_memcpy(ptr, png_ptr->save_buffer_ptr, save_size);
658 length -= save_size;
659 ptr += save_size;
660 png_ptr->buffer_size -= save_size;
661 png_ptr->save_buffer_size -= save_size;
662 png_ptr->save_buffer_ptr += save_size;
663 }
664
665 if (length && png_ptr->current_buffer_size)
666 {
667 png_size_t save_size;
668
669 if (length < png_ptr->current_buffer_size)
670 save_size = length;
671
672 else
673 save_size = png_ptr->current_buffer_size;
674
675 png_memcpy(ptr, png_ptr->current_buffer_ptr, save_size);
676 png_ptr->buffer_size -= save_size;
677 png_ptr->current_buffer_size -= save_size;
678 png_ptr->current_buffer_ptr += save_size;
679 }
680 }
681
682 void /* PRIVATE */
683 png_push_save_buffer(png_structp png_ptr)
684 {
685 if (png_ptr->save_buffer_size)
686 {
687 if (png_ptr->save_buffer_ptr != png_ptr->save_buffer)
688 {
689 png_size_t i, istop;
690 png_bytep sp;
691 png_bytep dp;
692
693 istop = png_ptr->save_buffer_size;
694
695 for (i = 0, sp = png_ptr->save_buffer_ptr, dp = png_ptr->save_buffer;
696 i < istop; i++, sp++, dp++)
697 {
698 *dp = *sp;
699 }
700 }
701 }
702
703 if (png_ptr->save_buffer_size + png_ptr->current_buffer_size >
704 png_ptr->save_buffer_max)
705 {
706 png_size_t new_max;
707 png_bytep old_buffer;
708
709 if (png_ptr->save_buffer_size > PNG_SIZE_MAX -
710 (png_ptr->current_buffer_size + 256))
711 {
712 png_error(png_ptr, "Potential overflow of save_buffer");
713 }
714
715 new_max = png_ptr->save_buffer_size + png_ptr->current_buffer_size + 256;
716 old_buffer = png_ptr->save_buffer;
717 png_ptr->save_buffer = (png_bytep)png_malloc_warn(png_ptr, new_max);
718
719 if (png_ptr->save_buffer == NULL)
720 {
721 png_free(png_ptr, old_buffer);
722 png_error(png_ptr, "Insufficient memory for save_buffer");
723 }
724
725 png_memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size);
726 png_free(png_ptr, old_buffer);
727 png_ptr->save_buffer_max = new_max;
728 }
729
730 if (png_ptr->current_buffer_size)
731 {
732 png_memcpy(png_ptr->save_buffer + png_ptr->save_buffer_size,
733 png_ptr->current_buffer_ptr, png_ptr->current_buffer_size);
734 png_ptr->save_buffer_size += png_ptr->current_buffer_size;
735 png_ptr->current_buffer_size = 0;
736 }
737
738 png_ptr->save_buffer_ptr = png_ptr->save_buffer;
739 png_ptr->buffer_size = 0;
740 }
741
742 void /* PRIVATE */
743 png_push_restore_buffer(png_structp png_ptr, png_bytep buffer,
744 png_size_t buffer_length)
745 {
746 png_ptr->current_buffer = buffer;
747 png_ptr->current_buffer_size = buffer_length;
748 png_ptr->buffer_size = buffer_length + png_ptr->save_buffer_size;
749 png_ptr->current_buffer_ptr = png_ptr->current_buffer;
750 }
751
752 void /* PRIVATE */
753 png_push_read_IDAT(png_structp png_ptr)
754 {
755 if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
756 {
757 png_byte chunk_length[4];
758 png_byte chunk_tag[4];
759
760 /* TODO: this code can be commoned up with the same code in push_read */
761 if (png_ptr->buffer_size < 8)
762 {
763 png_push_save_buffer(png_ptr);
764 return;
765 }
766
767 png_push_fill_buffer(png_ptr, chunk_length, 4);
768 png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
769 png_reset_crc(png_ptr);
770 png_crc_read(png_ptr, chunk_tag, 4);
771 png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag);
772 png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
773
774 if (png_ptr->chunk_name != png_IDAT)
775 {
776 png_ptr->process_mode = PNG_READ_CHUNK_MODE;
777
778 if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
779 png_error(png_ptr, "Not enough compressed data");
780
781 return;
782 }
783
784 png_ptr->idat_size = png_ptr->push_length;
785 }
786
787 if (png_ptr->idat_size && png_ptr->save_buffer_size)
788 {
789 png_size_t save_size = png_ptr->save_buffer_size;
790 png_uint_32 idat_size = png_ptr->idat_size;
791
792 /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
793 * are of different types and we don't know which variable has the fewest
794 * bits. Carefully select the smaller and cast it to the type of the
795 * larger - this cannot overflow. Do not cast in the following test - it
796 * will break on either 16 or 64 bit platforms.
797 */
798 if (idat_size < save_size)
799 save_size = (png_size_t)idat_size;
800
801 else
802 idat_size = (png_uint_32)save_size;
803
804 png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
805
806 png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size);
807
808 png_ptr->idat_size -= idat_size;
809 png_ptr->buffer_size -= save_size;
810 png_ptr->save_buffer_size -= save_size;
811 png_ptr->save_buffer_ptr += save_size;
812 }
813
814 if (png_ptr->idat_size && png_ptr->current_buffer_size)
815 {
816 png_size_t save_size = png_ptr->current_buffer_size;
817 png_uint_32 idat_size = png_ptr->idat_size;
818
819 /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
820 * are of different types and we don't know which variable has the fewest
821 * bits. Carefully select the smaller and cast it to the type of the
822 * larger - this cannot overflow.
823 */
824 if (idat_size < save_size)
825 save_size = (png_size_t)idat_size;
826
827 else
828 idat_size = (png_uint_32)save_size;
829
830 png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
831
832 png_process_IDAT_data(png_ptr, png_ptr->current_buffer_ptr, save_size);
833
834 png_ptr->idat_size -= idat_size;
835 png_ptr->buffer_size -= save_size;
836 png_ptr->current_buffer_size -= save_size;
837 png_ptr->current_buffer_ptr += save_size;
838 }
839
840 if (!png_ptr->idat_size)
841 {
842 if (png_ptr->buffer_size < 4)
843 {
844 png_push_save_buffer(png_ptr);
845 return;
846 }
847
848 png_crc_finish(png_ptr, 0);
849 png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
850 png_ptr->mode |= PNG_AFTER_IDAT;
851 }
852 }
853
854 void /* PRIVATE */
855 png_process_IDAT_data(png_structp png_ptr, png_bytep buffer,
856 png_size_t buffer_length)
857 {
858 /* The caller checks for a non-zero buffer length. */
859 if (!(buffer_length > 0) || buffer == NULL)
860 png_error(png_ptr, "No IDAT data (internal error)");
861
862 /* This routine must process all the data it has been given
863 * before returning, calling the row callback as required to
864 * handle the uncompressed results.
865 */
866 png_ptr->zstream.next_in = buffer;
867 png_ptr->zstream.avail_in = (uInt)buffer_length;
868
869 /* Keep going until the decompressed data is all processed
870 * or the stream marked as finished.
871 */
872 while (png_ptr->zstream.avail_in > 0 &&
873 !(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
874 {
875 int ret;
876
877 /* We have data for zlib, but we must check that zlib
878 * has someplace to put the results. It doesn't matter
879 * if we don't expect any results -- it may be the input
880 * data is just the LZ end code.
881 */
882 if (!(png_ptr->zstream.avail_out > 0))
883 {
884 png_ptr->zstream.avail_out =
885 (uInt) PNG_ROWBYTES(png_ptr->pixel_depth,
886 png_ptr->iwidth) + 1;
887
888 png_ptr->zstream.next_out = png_ptr->row_buf;
889 }
890
891 /* Using Z_SYNC_FLUSH here means that an unterminated
892 * LZ stream (a stream with a missing end code) can still
893 * be handled, otherwise (Z_NO_FLUSH) a future zlib
894 * implementation might defer output and therefore
895 * change the current behavior (see comments in inflate.c
896 * for why this doesn't happen at present with zlib 1.2.5).
897 */
898 ret = inflate(&png_ptr->zstream, Z_SYNC_FLUSH);
899
900 /* Check for any failure before proceeding. */
901 if (ret != Z_OK && ret != Z_STREAM_END)
902 {
903 /* Terminate the decompression. */
904 png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
905
906 /* This may be a truncated stream (missing or
907 * damaged end code). Treat that as a warning.
908 */
909 if (png_ptr->row_number >= png_ptr->num_rows ||
910 png_ptr->pass > 6)
911 png_warning(png_ptr, "Truncated compressed data in IDAT");
912
913 else
914 png_error(png_ptr, "Decompression error in IDAT");
915
916 /* Skip the check on unprocessed input */
917 return;
918 }
919
920 /* Did inflate output any data? */
921 if (png_ptr->zstream.next_out != png_ptr->row_buf)
922 {
923 /* Is this unexpected data after the last row?
924 * If it is, artificially terminate the LZ output
925 * here.
926 */
927 if (png_ptr->row_number >= png_ptr->num_rows ||
928 png_ptr->pass > 6)
929 {
930 /* Extra data. */
931 png_warning(png_ptr, "Extra compressed data in IDAT");
932 png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
933
934 /* Do no more processing; skip the unprocessed
935 * input check below.
936 */
937 return;
938 }
939
940 /* Do we have a complete row? */
941 if (png_ptr->zstream.avail_out == 0)
942 png_push_process_row(png_ptr);
943 }
944
945 /* And check for the end of the stream. */
946 if (ret == Z_STREAM_END)
947 png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
948 }
949
950 /* All the data should have been processed, if anything
951 * is left at this point we have bytes of IDAT data
952 * after the zlib end code.
953 */
954 if (png_ptr->zstream.avail_in > 0)
955 png_warning(png_ptr, "Extra compression data in IDAT");
956 }
957
958 void /* PRIVATE */
959 png_push_process_row(png_structp png_ptr)
960 {
961 /* 1.5.6: row_info moved out of png_struct to a local here. */
962 png_row_info row_info;
963
964 row_info.width = png_ptr->iwidth; /* NOTE: width of current interlaced row */
965 row_info.color_type = png_ptr->color_type;
966 row_info.bit_depth = png_ptr->bit_depth;
967 row_info.channels = png_ptr->channels;
968 row_info.pixel_depth = png_ptr->pixel_depth;
969 row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
970
971 if (png_ptr->row_buf[0] > PNG_FILTER_VALUE_NONE)
972 {
973 if (png_ptr->row_buf[0] < PNG_FILTER_VALUE_LAST)
974 png_read_filter_row(png_ptr, &row_info, png_ptr->row_buf + 1,
975 png_ptr->prev_row + 1, png_ptr->row_buf[0]);
976 else
977 png_error(png_ptr, "bad adaptive filter value");
978 }
979
980 /* libpng 1.5.6: the following line was copying png_ptr->rowbytes before
981 * 1.5.6, while the buffer really is this big in current versions of libpng
982 * it may not be in the future, so this was changed just to copy the
983 * interlaced row count:
984 */
985 png_memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1);
986
987 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
988 if (png_ptr->transformations)
989 png_do_read_transformations(png_ptr, &row_info);
990 #endif
991
992 /* The transformed pixel depth should match the depth now in row_info. */
993 if (png_ptr->transformed_pixel_depth == 0)
994 {
995 png_ptr->transformed_pixel_depth = row_info.pixel_depth;
996 if (row_info.pixel_depth > png_ptr->maximum_pixel_depth)
997 png_error(png_ptr, "progressive row overflow");
998 }
999
1000 else if (png_ptr->transformed_pixel_depth != row_info.pixel_depth)
1001 png_error(png_ptr, "internal progressive row size calculation error");
1002
1003
1004 #ifdef PNG_READ_INTERLACING_SUPPORTED
1005 /* Blow up interlaced rows to full size */
1006 if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
1007 {
1008 if (png_ptr->pass < 6)
1009 png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass,
1010 png_ptr->transformations);
1011
1012 switch (png_ptr->pass)
1013 {
1014 case 0:
1015 {
1016 int i;
1017 for (i = 0; i < 8 && png_ptr->pass == 0; i++)
1018 {
1019 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1020 png_read_push_finish_row(png_ptr); /* Updates png_ptr->pass */
1021 }
1022
1023 if (png_ptr->pass == 2) /* Pass 1 might be empty */
1024 {
1025 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
1026 {
1027 png_push_have_row(png_ptr, NULL);
1028 png_read_push_finish_row(png_ptr);
1029 }
1030 }
1031
1032 if (png_ptr->pass == 4 && png_ptr->height <= 4)
1033 {
1034 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
1035 {
1036 png_push_have_row(png_ptr, NULL);
1037 png_read_push_finish_row(png_ptr);
1038 }
1039 }
1040
1041 if (png_ptr->pass == 6 && png_ptr->height <= 4)
1042 {
1043 png_push_have_row(png_ptr, NULL);
1044 png_read_push_finish_row(png_ptr);
1045 }
1046
1047 break;
1048 }
1049
1050 case 1:
1051 {
1052 int i;
1053 for (i = 0; i < 8 && png_ptr->pass == 1; i++)
1054 {
1055 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1056 png_read_push_finish_row(png_ptr);
1057 }
1058
1059 if (png_ptr->pass == 2) /* Skip top 4 generated rows */
1060 {
1061 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
1062 {
1063 png_push_have_row(png_ptr, NULL);
1064 png_read_push_finish_row(png_ptr);
1065 }
1066 }
1067
1068 break;
1069 }
1070
1071 case 2:
1072 {
1073 int i;
1074
1075 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
1076 {
1077 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1078 png_read_push_finish_row(png_ptr);
1079 }
1080
1081 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
1082 {
1083 png_push_have_row(png_ptr, NULL);
1084 png_read_push_finish_row(png_ptr);
1085 }
1086
1087 if (png_ptr->pass == 4) /* Pass 3 might be empty */
1088 {
1089 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
1090 {
1091 png_push_have_row(png_ptr, NULL);
1092 png_read_push_finish_row(png_ptr);
1093 }
1094 }
1095
1096 break;
1097 }
1098
1099 case 3:
1100 {
1101 int i;
1102
1103 for (i = 0; i < 4 && png_ptr->pass == 3; i++)
1104 {
1105 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1106 png_read_push_finish_row(png_ptr);
1107 }
1108
1109 if (png_ptr->pass == 4) /* Skip top two generated rows */
1110 {
1111 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
1112 {
1113 png_push_have_row(png_ptr, NULL);
1114 png_read_push_finish_row(png_ptr);
1115 }
1116 }
1117
1118 break;
1119 }
1120
1121 case 4:
1122 {
1123 int i;
1124
1125 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
1126 {
1127 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1128 png_read_push_finish_row(png_ptr);
1129 }
1130
1131 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
1132 {
1133 png_push_have_row(png_ptr, NULL);
1134 png_read_push_finish_row(png_ptr);
1135 }
1136
1137 if (png_ptr->pass == 6) /* Pass 5 might be empty */
1138 {
1139 png_push_have_row(png_ptr, NULL);
1140 png_read_push_finish_row(png_ptr);
1141 }
1142
1143 break;
1144 }
1145
1146 case 5:
1147 {
1148 int i;
1149
1150 for (i = 0; i < 2 && png_ptr->pass == 5; i++)
1151 {
1152 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1153 png_read_push_finish_row(png_ptr);
1154 }
1155
1156 if (png_ptr->pass == 6) /* Skip top generated row */
1157 {
1158 png_push_have_row(png_ptr, NULL);
1159 png_read_push_finish_row(png_ptr);
1160 }
1161
1162 break;
1163 }
1164
1165 default:
1166 case 6:
1167 {
1168 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1169 png_read_push_finish_row(png_ptr);
1170
1171 if (png_ptr->pass != 6)
1172 break;
1173
1174 png_push_have_row(png_ptr, NULL);
1175 png_read_push_finish_row(png_ptr);
1176 }
1177 }
1178 }
1179 else
1180 #endif
1181 {
1182 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1183 png_read_push_finish_row(png_ptr);
1184 }
1185 }
1186
1187 void /* PRIVATE */
1188 png_read_push_finish_row(png_structp png_ptr)
1189 {
1190 #ifdef PNG_READ_INTERLACING_SUPPORTED
1191 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
1192
1193 /* Start of interlace block */
1194 static PNG_CONST png_byte FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
1195
1196 /* Offset to next interlace block */
1197 static PNG_CONST png_byte FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
1198
1199 /* Start of interlace block in the y direction */
1200 static PNG_CONST png_byte FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
1201
1202 /* Offset to next interlace block in the y direction */
1203 static PNG_CONST png_byte FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
1204
1205 /* Height of interlace block. This is not currently used - if you need
1206 * it, uncomment it here and in png.h
1207 static PNG_CONST png_byte FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
1208 */
1209 #endif
1210
1211 png_ptr->row_number++;
1212 if (png_ptr->row_number < png_ptr->num_rows)
1213 return;
1214
1215 #ifdef PNG_READ_INTERLACING_SUPPORTED
1216 if (png_ptr->interlaced)
1217 {
1218 png_ptr->row_number = 0;
1219 png_memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
1220
1221 do
1222 {
1223 png_ptr->pass++;
1224 if ((png_ptr->pass == 1 && png_ptr->width < 5) ||
1225 (png_ptr->pass == 3 && png_ptr->width < 3) ||
1226 (png_ptr->pass == 5 && png_ptr->width < 2))
1227 png_ptr->pass++;
1228
1229 if (png_ptr->pass > 7)
1230 png_ptr->pass--;
1231
1232 if (png_ptr->pass >= 7)
1233 break;
1234
1235 png_ptr->iwidth = (png_ptr->width +
1236 png_pass_inc[png_ptr->pass] - 1 -
1237 png_pass_start[png_ptr->pass]) /
1238 png_pass_inc[png_ptr->pass];
1239
1240 if (png_ptr->transformations & PNG_INTERLACE)
1241 break;
1242
1243 png_ptr->num_rows = (png_ptr->height +
1244 png_pass_yinc[png_ptr->pass] - 1 -
1245 png_pass_ystart[png_ptr->pass]) /
1246 png_pass_yinc[png_ptr->pass];
1247
1248 } while (png_ptr->iwidth == 0 || png_ptr->num_rows == 0);
1249 }
1250 #endif /* PNG_READ_INTERLACING_SUPPORTED */
1251 }
1252
1253 void /* PRIVATE */
1254 png_push_have_info(png_structp png_ptr, png_infop info_ptr)
1255 {
1256 if (png_ptr->info_fn != NULL)
1257 (*(png_ptr->info_fn))(png_ptr, info_ptr);
1258 }
1259
1260 void /* PRIVATE */
1261 png_push_have_end(png_structp png_ptr, png_infop info_ptr)
1262 {
1263 if (png_ptr->end_fn != NULL)
1264 (*(png_ptr->end_fn))(png_ptr, info_ptr);
1265 }
1266
1267 void /* PRIVATE */
1268 png_push_have_row(png_structp png_ptr, png_bytep row)
1269 {
1270 if (png_ptr->row_fn != NULL)
1271 (*(png_ptr->row_fn))(png_ptr, row, png_ptr->row_number,
1272 (int)png_ptr->pass);
1273 }
1274
1275 #ifdef PNG_READ_INTERLACING_SUPPORTED
1276 void PNGAPI
1277 png_progressive_combine_row (png_structp png_ptr, png_bytep old_row,
1278 png_const_bytep new_row)
1279 {
1280 if (png_ptr == NULL)
1281 return;
1282
1283 /* new_row is a flag here - if it is NULL then the app callback was called
1284 * from an empty row (see the calls to png_struct::row_fn below), otherwise
1285 * it must be png_ptr->row_buf+1
1286 */
1287 if (new_row != NULL)
1288 png_combine_row(png_ptr, old_row, 1/*display*/);
1289 }
1290 #endif /* PNG_READ_INTERLACING_SUPPORTED */
1291
1292 void PNGAPI
1293 png_set_progressive_read_fn(png_structp png_ptr, png_voidp progressive_ptr,
1294 png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,
1295 png_progressive_end_ptr end_fn)
1296 {
1297 if (png_ptr == NULL)
1298 return;
1299
1300 png_ptr->info_fn = info_fn;
1301 png_ptr->row_fn = row_fn;
1302 png_ptr->end_fn = end_fn;
1303
1304 png_set_read_fn(png_ptr, progressive_ptr, png_push_fill_buffer);
1305 }
1306
1307 png_voidp PNGAPI
1308 png_get_progressive_ptr(png_const_structp png_ptr)
1309 {
1310 if (png_ptr == NULL)
1311 return (NULL);
1312
1313 return png_ptr->io_ptr;
1314 }
1315 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */