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[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 1.5.2 [March 31, 2011]
5 * Copyright (c) 1998-2011 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 #ifdef PNG_READ_tEXt_SUPPORTED
132 case PNG_READ_tEXt_MODE:
133 {
134 png_push_read_tEXt(png_ptr, info_ptr);
135 break;
136 }
137
138 #endif
139 #ifdef PNG_READ_zTXt_SUPPORTED
140 case PNG_READ_zTXt_MODE:
141 {
142 png_push_read_zTXt(png_ptr, info_ptr);
143 break;
144 }
145
146 #endif
147 #ifdef PNG_READ_iTXt_SUPPORTED
148 case PNG_READ_iTXt_MODE:
149 {
150 png_push_read_iTXt(png_ptr, info_ptr);
151 break;
152 }
153
154 #endif
155 case PNG_SKIP_MODE:
156 {
157 png_push_crc_finish(png_ptr);
158 break;
159 }
160
161 default:
162 {
163 png_ptr->buffer_size = 0;
164 break;
165 }
166 }
167 }
168
169 /* Read any remaining signature bytes from the stream and compare them with
170 * the correct PNG signature. It is possible that this routine is called
171 * with bytes already read from the signature, either because they have been
172 * checked by the calling application, or because of multiple calls to this
173 * routine.
174 */
175 void /* PRIVATE */
176 png_push_read_sig(png_structp png_ptr, png_infop info_ptr)
177 {
178 png_size_t num_checked = png_ptr->sig_bytes,
179 num_to_check = 8 - num_checked;
180
181 if (png_ptr->buffer_size < num_to_check)
182 {
183 num_to_check = png_ptr->buffer_size;
184 }
185
186 png_push_fill_buffer(png_ptr, &(info_ptr->signature[num_checked]),
187 num_to_check);
188 png_ptr->sig_bytes = (png_byte)(png_ptr->sig_bytes + num_to_check);
189
190 if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
191 {
192 if (num_checked < 4 &&
193 png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
194 png_error(png_ptr, "Not a PNG file");
195
196 else
197 png_error(png_ptr, "PNG file corrupted by ASCII conversion");
198 }
199 else
200 {
201 if (png_ptr->sig_bytes >= 8)
202 {
203 png_ptr->process_mode = PNG_READ_CHUNK_MODE;
204 }
205 }
206 }
207
208 void /* PRIVATE */
209 png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
210 {
211 PNG_IHDR;
212 PNG_IDAT;
213 PNG_IEND;
214 PNG_PLTE;
215 #ifdef PNG_READ_bKGD_SUPPORTED
216 PNG_bKGD;
217 #endif
218 #ifdef PNG_READ_cHRM_SUPPORTED
219 PNG_cHRM;
220 #endif
221 #ifdef PNG_READ_gAMA_SUPPORTED
222 PNG_gAMA;
223 #endif
224 #ifdef PNG_READ_hIST_SUPPORTED
225 PNG_hIST;
226 #endif
227 #ifdef PNG_READ_iCCP_SUPPORTED
228 PNG_iCCP;
229 #endif
230 #ifdef PNG_READ_iTXt_SUPPORTED
231 PNG_iTXt;
232 #endif
233 #ifdef PNG_READ_oFFs_SUPPORTED
234 PNG_oFFs;
235 #endif
236 #ifdef PNG_READ_pCAL_SUPPORTED
237 PNG_pCAL;
238 #endif
239 #ifdef PNG_READ_pHYs_SUPPORTED
240 PNG_pHYs;
241 #endif
242 #ifdef PNG_READ_sBIT_SUPPORTED
243 PNG_sBIT;
244 #endif
245 #ifdef PNG_READ_sCAL_SUPPORTED
246 PNG_sCAL;
247 #endif
248 #ifdef PNG_READ_sRGB_SUPPORTED
249 PNG_sRGB;
250 #endif
251 #ifdef PNG_READ_sPLT_SUPPORTED
252 PNG_sPLT;
253 #endif
254 #ifdef PNG_READ_tEXt_SUPPORTED
255 PNG_tEXt;
256 #endif
257 #ifdef PNG_READ_tIME_SUPPORTED
258 PNG_tIME;
259 #endif
260 #ifdef PNG_READ_tRNS_SUPPORTED
261 PNG_tRNS;
262 #endif
263 #ifdef PNG_READ_zTXt_SUPPORTED
264 PNG_zTXt;
265 #endif
266
267 /* First we make sure we have enough data for the 4 byte chunk name
268 * and the 4 byte chunk length before proceeding with decoding the
269 * chunk data. To fully decode each of these chunks, we also make
270 * sure we have enough data in the buffer for the 4 byte CRC at the
271 * end of every chunk (except IDAT, which is handled separately).
272 */
273 if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
274 {
275 png_byte chunk_length[4];
276
277 if (png_ptr->buffer_size < 8)
278 {
279 png_push_save_buffer(png_ptr);
280 return;
281 }
282
283 png_push_fill_buffer(png_ptr, chunk_length, 4);
284 png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
285 png_reset_crc(png_ptr);
286 png_crc_read(png_ptr, png_ptr->chunk_name, 4);
287 png_check_chunk_name(png_ptr, png_ptr->chunk_name);
288 png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
289 }
290
291 if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
292 if (png_ptr->mode & PNG_AFTER_IDAT)
293 png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
294
295 if (!png_memcmp(png_ptr->chunk_name, png_IHDR, 4))
296 {
297 if (png_ptr->push_length != 13)
298 png_error(png_ptr, "Invalid IHDR length");
299
300 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
301 {
302 png_push_save_buffer(png_ptr);
303 return;
304 }
305
306 png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length);
307 }
308
309 else if (!png_memcmp(png_ptr->chunk_name, png_IEND, 4))
310 {
311 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
312 {
313 png_push_save_buffer(png_ptr);
314 return;
315 }
316
317 png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length);
318
319 png_ptr->process_mode = PNG_READ_DONE_MODE;
320 png_push_have_end(png_ptr, info_ptr);
321 }
322
323 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
324 else if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name))
325 {
326 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
327 {
328 png_push_save_buffer(png_ptr);
329 return;
330 }
331
332 if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
333 png_ptr->mode |= PNG_HAVE_IDAT;
334
335 png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length);
336
337 if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
338 png_ptr->mode |= PNG_HAVE_PLTE;
339
340 else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
341 {
342 if (!(png_ptr->mode & PNG_HAVE_IHDR))
343 png_error(png_ptr, "Missing IHDR before IDAT");
344
345 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
346 !(png_ptr->mode & PNG_HAVE_PLTE))
347 png_error(png_ptr, "Missing PLTE before IDAT");
348 }
349 }
350
351 #endif
352 else if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
353 {
354 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
355 {
356 png_push_save_buffer(png_ptr);
357 return;
358 }
359 png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
360 }
361
362 else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
363 {
364 /* If we reach an IDAT chunk, this means we have read all of the
365 * header chunks, and we can start reading the image (or if this
366 * is called after the image has been read - we have an error).
367 */
368
369 if (!(png_ptr->mode & PNG_HAVE_IHDR))
370 png_error(png_ptr, "Missing IHDR before IDAT");
371
372 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
373 !(png_ptr->mode & PNG_HAVE_PLTE))
374 png_error(png_ptr, "Missing PLTE before IDAT");
375
376 if (png_ptr->mode & PNG_HAVE_IDAT)
377 {
378 if (!(png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
379 if (png_ptr->push_length == 0)
380 return;
381
382 if (png_ptr->mode & PNG_AFTER_IDAT)
383 png_benign_error(png_ptr, "Too many IDATs found");
384 }
385
386 png_ptr->idat_size = png_ptr->push_length;
387 png_ptr->mode |= PNG_HAVE_IDAT;
388 png_ptr->process_mode = PNG_READ_IDAT_MODE;
389 png_push_have_info(png_ptr, info_ptr);
390 png_ptr->zstream.avail_out =
391 (uInt) PNG_ROWBYTES(png_ptr->pixel_depth,
392 png_ptr->iwidth) + 1;
393 png_ptr->zstream.next_out = png_ptr->row_buf;
394 return;
395 }
396
397 #ifdef PNG_READ_gAMA_SUPPORTED
398 else if (!png_memcmp(png_ptr->chunk_name, png_gAMA, 4))
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_gAMA(png_ptr, info_ptr, png_ptr->push_length);
407 }
408
409 #endif
410 #ifdef PNG_READ_sBIT_SUPPORTED
411 else if (!png_memcmp(png_ptr->chunk_name, png_sBIT, 4))
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_sBIT(png_ptr, info_ptr, png_ptr->push_length);
420 }
421
422 #endif
423 #ifdef PNG_READ_cHRM_SUPPORTED
424 else if (!png_memcmp(png_ptr->chunk_name, png_cHRM, 4))
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_cHRM(png_ptr, info_ptr, png_ptr->push_length);
433 }
434
435 #endif
436 #ifdef PNG_READ_sRGB_SUPPORTED
437 else if (!png_memcmp(png_ptr->chunk_name, png_sRGB, 4))
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_sRGB(png_ptr, info_ptr, png_ptr->push_length);
446 }
447
448 #endif
449 #ifdef PNG_READ_iCCP_SUPPORTED
450 else if (!png_memcmp(png_ptr->chunk_name, png_iCCP, 4))
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_iCCP(png_ptr, info_ptr, png_ptr->push_length);
459 }
460
461 #endif
462 #ifdef PNG_READ_sPLT_SUPPORTED
463 else if (!png_memcmp(png_ptr->chunk_name, png_sPLT, 4))
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_sPLT(png_ptr, info_ptr, png_ptr->push_length);
472 }
473
474 #endif
475 #ifdef PNG_READ_tRNS_SUPPORTED
476 else if (!png_memcmp(png_ptr->chunk_name, png_tRNS, 4))
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_tRNS(png_ptr, info_ptr, png_ptr->push_length);
485 }
486
487 #endif
488 #ifdef PNG_READ_bKGD_SUPPORTED
489 else if (!png_memcmp(png_ptr->chunk_name, png_bKGD, 4))
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_bKGD(png_ptr, info_ptr, png_ptr->push_length);
498 }
499
500 #endif
501 #ifdef PNG_READ_hIST_SUPPORTED
502 else if (!png_memcmp(png_ptr->chunk_name, png_hIST, 4))
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_hIST(png_ptr, info_ptr, png_ptr->push_length);
511 }
512
513 #endif
514 #ifdef PNG_READ_pHYs_SUPPORTED
515 else if (!png_memcmp(png_ptr->chunk_name, png_pHYs, 4))
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_pHYs(png_ptr, info_ptr, png_ptr->push_length);
524 }
525
526 #endif
527 #ifdef PNG_READ_oFFs_SUPPORTED
528 else if (!png_memcmp(png_ptr->chunk_name, png_oFFs, 4))
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_oFFs(png_ptr, info_ptr, png_ptr->push_length);
537 }
538 #endif
539
540 #ifdef PNG_READ_pCAL_SUPPORTED
541 else if (!png_memcmp(png_ptr->chunk_name, png_pCAL, 4))
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_pCAL(png_ptr, info_ptr, png_ptr->push_length);
550 }
551
552 #endif
553 #ifdef PNG_READ_sCAL_SUPPORTED
554 else if (!png_memcmp(png_ptr->chunk_name, png_sCAL, 4))
555 {
556 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
557 {
558 png_push_save_buffer(png_ptr);
559 return;
560 }
561
562 png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length);
563 }
564
565 #endif
566 #ifdef PNG_READ_tIME_SUPPORTED
567 else if (!png_memcmp(png_ptr->chunk_name, png_tIME, 4))
568 {
569 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
570 {
571 png_push_save_buffer(png_ptr);
572 return;
573 }
574
575 png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length);
576 }
577
578 #endif
579 #ifdef PNG_READ_tEXt_SUPPORTED
580 else if (!png_memcmp(png_ptr->chunk_name, png_tEXt, 4))
581 {
582 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
583 {
584 png_push_save_buffer(png_ptr);
585 return;
586 }
587
588 png_push_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length);
589 }
590
591 #endif
592 #ifdef PNG_READ_zTXt_SUPPORTED
593 else if (!png_memcmp(png_ptr->chunk_name, png_zTXt, 4))
594 {
595 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
596 {
597 png_push_save_buffer(png_ptr);
598 return;
599 }
600
601 png_push_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
602 }
603
604 #endif
605 #ifdef PNG_READ_iTXt_SUPPORTED
606 else if (!png_memcmp(png_ptr->chunk_name, png_iTXt, 4))
607 {
608 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
609 {
610 png_push_save_buffer(png_ptr);
611 return;
612 }
613
614 png_push_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
615 }
616
617 #endif
618 else
619 {
620 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
621 {
622 png_push_save_buffer(png_ptr);
623 return;
624 }
625 png_push_handle_unknown(png_ptr, info_ptr, png_ptr->push_length);
626 }
627
628 png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
629 }
630
631 void /* PRIVATE */
632 png_push_crc_skip(png_structp png_ptr, png_uint_32 skip)
633 {
634 png_ptr->process_mode = PNG_SKIP_MODE;
635 png_ptr->skip_length = skip;
636 }
637
638 void /* PRIVATE */
639 png_push_crc_finish(png_structp png_ptr)
640 {
641 if (png_ptr->skip_length && png_ptr->save_buffer_size)
642 {
643 png_size_t save_size = png_ptr->save_buffer_size;
644 png_uint_32 skip_length = png_ptr->skip_length;
645
646 /* We want the smaller of 'skip_length' and 'save_buffer_size', but
647 * they are of different types and we don't know which variable has the
648 * fewest bits. Carefully select the smaller and cast it to the type of
649 * the larger - this cannot overflow. Do not cast in the following test
650 * - it will break on either 16 or 64 bit platforms.
651 */
652 if (skip_length < save_size)
653 save_size = (png_size_t)skip_length;
654
655 else
656 skip_length = (png_uint_32)save_size;
657
658 png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
659
660 png_ptr->skip_length -= skip_length;
661 png_ptr->buffer_size -= save_size;
662 png_ptr->save_buffer_size -= save_size;
663 png_ptr->save_buffer_ptr += save_size;
664 }
665 if (png_ptr->skip_length && png_ptr->current_buffer_size)
666 {
667 png_size_t save_size = png_ptr->current_buffer_size;
668 png_uint_32 skip_length = png_ptr->skip_length;
669
670 /* We want the smaller of 'skip_length' and 'current_buffer_size', here,
671 * the same problem exists as above and the same solution.
672 */
673 if (skip_length < save_size)
674 save_size = (png_size_t)skip_length;
675
676 else
677 skip_length = (png_uint_32)save_size;
678
679 png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
680
681 png_ptr->skip_length -= skip_length;
682 png_ptr->buffer_size -= save_size;
683 png_ptr->current_buffer_size -= save_size;
684 png_ptr->current_buffer_ptr += save_size;
685 }
686 if (!png_ptr->skip_length)
687 {
688 if (png_ptr->buffer_size < 4)
689 {
690 png_push_save_buffer(png_ptr);
691 return;
692 }
693
694 png_crc_finish(png_ptr, 0);
695 png_ptr->process_mode = PNG_READ_CHUNK_MODE;
696 }
697 }
698
699 void PNGCBAPI
700 png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
701 {
702 png_bytep ptr;
703
704 if (png_ptr == NULL)
705 return;
706
707 ptr = buffer;
708 if (png_ptr->save_buffer_size)
709 {
710 png_size_t save_size;
711
712 if (length < png_ptr->save_buffer_size)
713 save_size = length;
714
715 else
716 save_size = png_ptr->save_buffer_size;
717
718 png_memcpy(ptr, png_ptr->save_buffer_ptr, save_size);
719 length -= save_size;
720 ptr += save_size;
721 png_ptr->buffer_size -= save_size;
722 png_ptr->save_buffer_size -= save_size;
723 png_ptr->save_buffer_ptr += save_size;
724 }
725 if (length && png_ptr->current_buffer_size)
726 {
727 png_size_t save_size;
728
729 if (length < png_ptr->current_buffer_size)
730 save_size = length;
731
732 else
733 save_size = png_ptr->current_buffer_size;
734
735 png_memcpy(ptr, png_ptr->current_buffer_ptr, save_size);
736 png_ptr->buffer_size -= save_size;
737 png_ptr->current_buffer_size -= save_size;
738 png_ptr->current_buffer_ptr += save_size;
739 }
740 }
741
742 void /* PRIVATE */
743 png_push_save_buffer(png_structp png_ptr)
744 {
745 if (png_ptr->save_buffer_size)
746 {
747 if (png_ptr->save_buffer_ptr != png_ptr->save_buffer)
748 {
749 png_size_t i, istop;
750 png_bytep sp;
751 png_bytep dp;
752
753 istop = png_ptr->save_buffer_size;
754 for (i = 0, sp = png_ptr->save_buffer_ptr, dp = png_ptr->save_buffer;
755 i < istop; i++, sp++, dp++)
756 {
757 *dp = *sp;
758 }
759 }
760 }
761 if (png_ptr->save_buffer_size + png_ptr->current_buffer_size >
762 png_ptr->save_buffer_max)
763 {
764 png_size_t new_max;
765 png_bytep old_buffer;
766
767 if (png_ptr->save_buffer_size > PNG_SIZE_MAX -
768 (png_ptr->current_buffer_size + 256))
769 {
770 png_error(png_ptr, "Potential overflow of save_buffer");
771 }
772
773 new_max = png_ptr->save_buffer_size + png_ptr->current_buffer_size + 256;
774 old_buffer = png_ptr->save_buffer;
775 png_ptr->save_buffer = (png_bytep)png_malloc_warn(png_ptr,
776 (png_size_t)new_max);
777
778 if (png_ptr->save_buffer == NULL)
779 {
780 png_free(png_ptr, old_buffer);
781 png_error(png_ptr, "Insufficient memory for save_buffer");
782 }
783
784 png_memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size);
785 png_free(png_ptr, old_buffer);
786 png_ptr->save_buffer_max = new_max;
787 }
788 if (png_ptr->current_buffer_size)
789 {
790 png_memcpy(png_ptr->save_buffer + png_ptr->save_buffer_size,
791 png_ptr->current_buffer_ptr, png_ptr->current_buffer_size);
792 png_ptr->save_buffer_size += png_ptr->current_buffer_size;
793 png_ptr->current_buffer_size = 0;
794 }
795 png_ptr->save_buffer_ptr = png_ptr->save_buffer;
796 png_ptr->buffer_size = 0;
797 }
798
799 void /* PRIVATE */
800 png_push_restore_buffer(png_structp png_ptr, png_bytep buffer,
801 png_size_t buffer_length)
802 {
803 png_ptr->current_buffer = buffer;
804 png_ptr->current_buffer_size = buffer_length;
805 png_ptr->buffer_size = buffer_length + png_ptr->save_buffer_size;
806 png_ptr->current_buffer_ptr = png_ptr->current_buffer;
807 }
808
809 void /* PRIVATE */
810 png_push_read_IDAT(png_structp png_ptr)
811 {
812 PNG_IDAT;
813 if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
814 {
815 png_byte chunk_length[4];
816
817 if (png_ptr->buffer_size < 8)
818 {
819 png_push_save_buffer(png_ptr);
820 return;
821 }
822
823 png_push_fill_buffer(png_ptr, chunk_length, 4);
824 png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
825 png_reset_crc(png_ptr);
826 png_crc_read(png_ptr, png_ptr->chunk_name, 4);
827 png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
828
829 if (png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
830 {
831 png_ptr->process_mode = PNG_READ_CHUNK_MODE;
832
833 if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
834 png_error(png_ptr, "Not enough compressed data");
835
836 return;
837 }
838
839 png_ptr->idat_size = png_ptr->push_length;
840 }
841 if (png_ptr->idat_size && png_ptr->save_buffer_size)
842 {
843 png_size_t save_size = png_ptr->save_buffer_size;
844 png_uint_32 idat_size = png_ptr->idat_size;
845
846 /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
847 * are of different types and we don't know which variable has the fewest
848 * bits. Carefully select the smaller and cast it to the type of the
849 * larger - this cannot overflow. Do not cast in the following test - it
850 * will break on either 16 or 64 bit platforms.
851 */
852 if (idat_size < save_size)
853 save_size = (png_size_t)idat_size;
854
855 else
856 idat_size = (png_uint_32)save_size;
857
858 png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
859
860 png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size);
861
862 png_ptr->idat_size -= idat_size;
863 png_ptr->buffer_size -= save_size;
864 png_ptr->save_buffer_size -= save_size;
865 png_ptr->save_buffer_ptr += save_size;
866 }
867
868 if (png_ptr->idat_size && png_ptr->current_buffer_size)
869 {
870 png_size_t save_size = png_ptr->current_buffer_size;
871 png_uint_32 idat_size = png_ptr->idat_size;
872
873 /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
874 * are of different types and we don't know which variable has the fewest
875 * bits. Carefully select the smaller and cast it to the type of the
876 * larger - this cannot overflow.
877 */
878 if (idat_size < save_size)
879 save_size = (png_size_t)idat_size;
880
881 else
882 idat_size = (png_uint_32)save_size;
883
884 png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
885
886 png_process_IDAT_data(png_ptr, png_ptr->current_buffer_ptr, save_size);
887
888 png_ptr->idat_size -= idat_size;
889 png_ptr->buffer_size -= save_size;
890 png_ptr->current_buffer_size -= save_size;
891 png_ptr->current_buffer_ptr += save_size;
892 }
893 if (!png_ptr->idat_size)
894 {
895 if (png_ptr->buffer_size < 4)
896 {
897 png_push_save_buffer(png_ptr);
898 return;
899 }
900
901 png_crc_finish(png_ptr, 0);
902 png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
903 png_ptr->mode |= PNG_AFTER_IDAT;
904 }
905 }
906
907 void /* PRIVATE */
908 png_process_IDAT_data(png_structp png_ptr, png_bytep buffer,
909 png_size_t buffer_length)
910 {
911 /* The caller checks for a non-zero buffer length. */
912 if (!(buffer_length > 0) || buffer == NULL)
913 png_error(png_ptr, "No IDAT data (internal error)");
914
915 /* This routine must process all the data it has been given
916 * before returning, calling the row callback as required to
917 * handle the uncompressed results.
918 */
919 png_ptr->zstream.next_in = buffer;
920 png_ptr->zstream.avail_in = (uInt)buffer_length;
921
922 /* Keep going until the decompressed data is all processed
923 * or the stream marked as finished.
924 */
925 while (png_ptr->zstream.avail_in > 0 &&
926 !(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
927 {
928 int ret;
929
930 /* We have data for zlib, but we must check that zlib
931 * has someplace to put the results. It doesn't matter
932 * if we don't expect any results -- it may be the input
933 * data is just the LZ end code.
934 */
935 if (!(png_ptr->zstream.avail_out > 0))
936 {
937 png_ptr->zstream.avail_out =
938 (uInt) PNG_ROWBYTES(png_ptr->pixel_depth,
939 png_ptr->iwidth) + 1;
940
941 png_ptr->zstream.next_out = png_ptr->row_buf;
942 }
943
944 /* Using Z_SYNC_FLUSH here means that an unterminated
945 * LZ stream (a stream with a missing end code) can still
946 * be handled, otherwise (Z_NO_FLUSH) a future zlib
947 * implementation might defer output and therefore
948 * change the current behavior (see comments in inflate.c
949 * for why this doesn't happen at present with zlib 1.2.5).
950 */
951 ret = inflate(&png_ptr->zstream, Z_SYNC_FLUSH);
952
953 /* Check for any failure before proceeding. */
954 if (ret != Z_OK && ret != Z_STREAM_END)
955 {
956 /* Terminate the decompression. */
957 png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
958
959 /* This may be a truncated stream (missing or
960 * damaged end code). Treat that as a warning.
961 */
962 if (png_ptr->row_number >= png_ptr->num_rows ||
963 png_ptr->pass > 6)
964 png_warning(png_ptr, "Truncated compressed data in IDAT");
965
966 else
967 png_error(png_ptr, "Decompression error in IDAT");
968
969 /* Skip the check on unprocessed input */
970 return;
971 }
972
973 /* Did inflate output any data? */
974 if (png_ptr->zstream.next_out != png_ptr->row_buf)
975 {
976 /* Is this unexpected data after the last row?
977 * If it is, artificially terminate the LZ output
978 * here.
979 */
980 if (png_ptr->row_number >= png_ptr->num_rows ||
981 png_ptr->pass > 6)
982 {
983 /* Extra data. */
984 png_warning(png_ptr, "Extra compressed data in IDAT");
985 png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
986
987 /* Do no more processing; skip the unprocessed
988 * input check below.
989 */
990 return;
991 }
992
993 /* Do we have a complete row? */
994 if (png_ptr->zstream.avail_out == 0)
995 png_push_process_row(png_ptr);
996 }
997
998 /* And check for the end of the stream. */
999 if (ret == Z_STREAM_END)
1000 png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
1001 }
1002
1003 /* All the data should have been processed, if anything
1004 * is left at this point we have bytes of IDAT data
1005 * after the zlib end code.
1006 */
1007 if (png_ptr->zstream.avail_in > 0)
1008 png_warning(png_ptr, "Extra compression data in IDAT");
1009 }
1010
1011 void /* PRIVATE */
1012 png_push_process_row(png_structp png_ptr)
1013 {
1014 png_ptr->row_info.color_type = png_ptr->color_type;
1015 png_ptr->row_info.width = png_ptr->iwidth;
1016 png_ptr->row_info.channels = png_ptr->channels;
1017 png_ptr->row_info.bit_depth = png_ptr->bit_depth;
1018 png_ptr->row_info.pixel_depth = png_ptr->pixel_depth;
1019
1020 png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth,
1021 png_ptr->row_info.width);
1022
1023 png_read_filter_row(png_ptr, &(png_ptr->row_info),
1024 png_ptr->row_buf + 1, png_ptr->prev_row + 1,
1025 (int)(png_ptr->row_buf[0]));
1026
1027 png_memcpy(png_ptr->prev_row, png_ptr->row_buf, png_ptr->rowbytes + 1);
1028
1029 if (png_ptr->transformations)
1030 png_do_read_transformations(png_ptr);
1031
1032 #ifdef PNG_READ_INTERLACING_SUPPORTED
1033 /* Blow up interlaced rows to full size */
1034 if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
1035 {
1036 if (png_ptr->pass < 6)
1037 /* old interface (pre-1.0.9):
1038 png_do_read_interlace(&(png_ptr->row_info),
1039 png_ptr->row_buf + 1, png_ptr->pass, png_ptr->transformations);
1040 */
1041 png_do_read_interlace(png_ptr);
1042
1043 switch (png_ptr->pass)
1044 {
1045 case 0:
1046 {
1047 int i;
1048 for (i = 0; i < 8 && png_ptr->pass == 0; i++)
1049 {
1050 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1051 png_read_push_finish_row(png_ptr); /* Updates png_ptr->pass */
1052 }
1053
1054 if (png_ptr->pass == 2) /* Pass 1 might be empty */
1055 {
1056 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
1057 {
1058 png_push_have_row(png_ptr, NULL);
1059 png_read_push_finish_row(png_ptr);
1060 }
1061 }
1062
1063 if (png_ptr->pass == 4 && png_ptr->height <= 4)
1064 {
1065 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
1066 {
1067 png_push_have_row(png_ptr, NULL);
1068 png_read_push_finish_row(png_ptr);
1069 }
1070 }
1071
1072 if (png_ptr->pass == 6 && png_ptr->height <= 4)
1073 {
1074 png_push_have_row(png_ptr, NULL);
1075 png_read_push_finish_row(png_ptr);
1076 }
1077
1078 break;
1079 }
1080
1081 case 1:
1082 {
1083 int i;
1084 for (i = 0; i < 8 && png_ptr->pass == 1; i++)
1085 {
1086 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1087 png_read_push_finish_row(png_ptr);
1088 }
1089
1090 if (png_ptr->pass == 2) /* Skip top 4 generated rows */
1091 {
1092 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
1093 {
1094 png_push_have_row(png_ptr, NULL);
1095 png_read_push_finish_row(png_ptr);
1096 }
1097 }
1098
1099 break;
1100 }
1101
1102 case 2:
1103 {
1104 int i;
1105
1106 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
1107 {
1108 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1109 png_read_push_finish_row(png_ptr);
1110 }
1111
1112 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
1113 {
1114 png_push_have_row(png_ptr, NULL);
1115 png_read_push_finish_row(png_ptr);
1116 }
1117
1118 if (png_ptr->pass == 4) /* Pass 3 might be empty */
1119 {
1120 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
1121 {
1122 png_push_have_row(png_ptr, NULL);
1123 png_read_push_finish_row(png_ptr);
1124 }
1125 }
1126
1127 break;
1128 }
1129
1130 case 3:
1131 {
1132 int i;
1133
1134 for (i = 0; i < 4 && png_ptr->pass == 3; i++)
1135 {
1136 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1137 png_read_push_finish_row(png_ptr);
1138 }
1139
1140 if (png_ptr->pass == 4) /* Skip top two generated rows */
1141 {
1142 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
1143 {
1144 png_push_have_row(png_ptr, NULL);
1145 png_read_push_finish_row(png_ptr);
1146 }
1147 }
1148
1149 break;
1150 }
1151
1152 case 4:
1153 {
1154 int i;
1155
1156 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
1157 {
1158 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1159 png_read_push_finish_row(png_ptr);
1160 }
1161
1162 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
1163 {
1164 png_push_have_row(png_ptr, NULL);
1165 png_read_push_finish_row(png_ptr);
1166 }
1167
1168 if (png_ptr->pass == 6) /* Pass 5 might be empty */
1169 {
1170 png_push_have_row(png_ptr, NULL);
1171 png_read_push_finish_row(png_ptr);
1172 }
1173
1174 break;
1175 }
1176
1177 case 5:
1178 {
1179 int i;
1180
1181 for (i = 0; i < 2 && png_ptr->pass == 5; i++)
1182 {
1183 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1184 png_read_push_finish_row(png_ptr);
1185 }
1186
1187 if (png_ptr->pass == 6) /* Skip top generated row */
1188 {
1189 png_push_have_row(png_ptr, NULL);
1190 png_read_push_finish_row(png_ptr);
1191 }
1192
1193 break;
1194 }
1195
1196 default:
1197 case 6:
1198 {
1199 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1200 png_read_push_finish_row(png_ptr);
1201
1202 if (png_ptr->pass != 6)
1203 break;
1204
1205 png_push_have_row(png_ptr, NULL);
1206 png_read_push_finish_row(png_ptr);
1207 }
1208 }
1209 }
1210 else
1211 #endif
1212 {
1213 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1214 png_read_push_finish_row(png_ptr);
1215 }
1216 }
1217
1218 void /* PRIVATE */
1219 png_read_push_finish_row(png_structp png_ptr)
1220 {
1221 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
1222
1223 /* Start of interlace block */
1224 PNG_CONST int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
1225
1226 /* Offset to next interlace block */
1227 PNG_CONST int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
1228
1229 /* Start of interlace block in the y direction */
1230 PNG_CONST int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
1231
1232 /* Offset to next interlace block in the y direction */
1233 PNG_CONST int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
1234
1235 /* Height of interlace block. This is not currently used - if you need
1236 * it, uncomment it here and in png.h
1237 PNG_CONST int FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
1238 */
1239
1240 png_ptr->row_number++;
1241 if (png_ptr->row_number < png_ptr->num_rows)
1242 return;
1243
1244 #ifdef PNG_READ_INTERLACING_SUPPORTED
1245 if (png_ptr->interlaced)
1246 {
1247 png_ptr->row_number = 0;
1248 png_memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
1249
1250 do
1251 {
1252 png_ptr->pass++;
1253 if ((png_ptr->pass == 1 && png_ptr->width < 5) ||
1254 (png_ptr->pass == 3 && png_ptr->width < 3) ||
1255 (png_ptr->pass == 5 && png_ptr->width < 2))
1256 png_ptr->pass++;
1257
1258 if (png_ptr->pass > 7)
1259 png_ptr->pass--;
1260
1261 if (png_ptr->pass >= 7)
1262 break;
1263
1264 png_ptr->iwidth = (png_ptr->width +
1265 png_pass_inc[png_ptr->pass] - 1 -
1266 png_pass_start[png_ptr->pass]) /
1267 png_pass_inc[png_ptr->pass];
1268
1269 if (png_ptr->transformations & PNG_INTERLACE)
1270 break;
1271
1272 png_ptr->num_rows = (png_ptr->height +
1273 png_pass_yinc[png_ptr->pass] - 1 -
1274 png_pass_ystart[png_ptr->pass]) /
1275 png_pass_yinc[png_ptr->pass];
1276
1277 } while (png_ptr->iwidth == 0 || png_ptr->num_rows == 0);
1278 }
1279 #endif /* PNG_READ_INTERLACING_SUPPORTED */
1280 }
1281
1282 #ifdef PNG_READ_tEXt_SUPPORTED
1283 void /* PRIVATE */
1284 png_push_handle_tEXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
1285 length)
1286 {
1287 if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
1288 {
1289 PNG_UNUSED(info_ptr) /* To quiet some compiler warnings */
1290 png_error(png_ptr, "Out of place tEXt");
1291 /*NOT REACHED*/
1292 }
1293
1294 #ifdef PNG_MAX_MALLOC_64K
1295 png_ptr->skip_length = 0; /* This may not be necessary */
1296
1297 if (length > (png_uint_32)65535L) /* Can't hold entire string in memory */
1298 {
1299 png_warning(png_ptr, "tEXt chunk too large to fit in memory");
1300 png_ptr->skip_length = length - (png_uint_32)65535L;
1301 length = (png_uint_32)65535L;
1302 }
1303 #endif
1304
1305 png_ptr->current_text = (png_charp)png_malloc(png_ptr,
1306 (png_size_t)(length + 1));
1307 png_ptr->current_text[length] = '\0';
1308 png_ptr->current_text_ptr = png_ptr->current_text;
1309 png_ptr->current_text_size = (png_size_t)length;
1310 png_ptr->current_text_left = (png_size_t)length;
1311 png_ptr->process_mode = PNG_READ_tEXt_MODE;
1312 }
1313
1314 void /* PRIVATE */
1315 png_push_read_tEXt(png_structp png_ptr, png_infop info_ptr)
1316 {
1317 if (png_ptr->buffer_size && png_ptr->current_text_left)
1318 {
1319 png_size_t text_size;
1320
1321 if (png_ptr->buffer_size < png_ptr->current_text_left)
1322 text_size = png_ptr->buffer_size;
1323
1324 else
1325 text_size = png_ptr->current_text_left;
1326
1327 png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
1328 png_ptr->current_text_left -= text_size;
1329 png_ptr->current_text_ptr += text_size;
1330 }
1331 if (!(png_ptr->current_text_left))
1332 {
1333 png_textp text_ptr;
1334 png_charp text;
1335 png_charp key;
1336 int ret;
1337
1338 if (png_ptr->buffer_size < 4)
1339 {
1340 png_push_save_buffer(png_ptr);
1341 return;
1342 }
1343
1344 png_push_crc_finish(png_ptr);
1345
1346 #ifdef PNG_MAX_MALLOC_64K
1347 if (png_ptr->skip_length)
1348 return;
1349 #endif
1350
1351 key = png_ptr->current_text;
1352
1353 for (text = key; *text; text++)
1354 /* Empty loop */ ;
1355
1356 if (text < key + png_ptr->current_text_size)
1357 text++;
1358
1359 text_ptr = (png_textp)png_malloc(png_ptr, png_sizeof(png_text));
1360 text_ptr->compression = PNG_TEXT_COMPRESSION_NONE;
1361 text_ptr->key = key;
1362 text_ptr->itxt_length = 0;
1363 text_ptr->lang = NULL;
1364 text_ptr->lang_key = NULL;
1365 text_ptr->text = text;
1366
1367 ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
1368
1369 png_free(png_ptr, key);
1370 png_free(png_ptr, text_ptr);
1371 png_ptr->current_text = NULL;
1372
1373 if (ret)
1374 png_warning(png_ptr, "Insufficient memory to store text chunk");
1375 }
1376 }
1377 #endif
1378
1379 #ifdef PNG_READ_zTXt_SUPPORTED
1380 void /* PRIVATE */
1381 png_push_handle_zTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
1382 length)
1383 {
1384 if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
1385 {
1386 PNG_UNUSED(info_ptr) /* To quiet some compiler warnings */
1387 png_error(png_ptr, "Out of place zTXt");
1388 /*NOT REACHED*/
1389 }
1390
1391 #ifdef PNG_MAX_MALLOC_64K
1392 /* We can't handle zTXt chunks > 64K, since we don't have enough space
1393 * to be able to store the uncompressed data. Actually, the threshold
1394 * is probably around 32K, but it isn't as definite as 64K is.
1395 */
1396 if (length > (png_uint_32)65535L)
1397 {
1398 png_warning(png_ptr, "zTXt chunk too large to fit in memory");
1399 png_push_crc_skip(png_ptr, length);
1400 return;
1401 }
1402 #endif
1403
1404 png_ptr->current_text = (png_charp)png_malloc(png_ptr,
1405 (png_size_t)(length + 1));
1406 png_ptr->current_text[length] = '\0';
1407 png_ptr->current_text_ptr = png_ptr->current_text;
1408 png_ptr->current_text_size = (png_size_t)length;
1409 png_ptr->current_text_left = (png_size_t)length;
1410 png_ptr->process_mode = PNG_READ_zTXt_MODE;
1411 }
1412
1413 void /* PRIVATE */
1414 png_push_read_zTXt(png_structp png_ptr, png_infop info_ptr)
1415 {
1416 if (png_ptr->buffer_size && png_ptr->current_text_left)
1417 {
1418 png_size_t text_size;
1419
1420 if (png_ptr->buffer_size < (png_uint_32)png_ptr->current_text_left)
1421 text_size = png_ptr->buffer_size;
1422
1423 else
1424 text_size = png_ptr->current_text_left;
1425
1426 png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
1427 png_ptr->current_text_left -= text_size;
1428 png_ptr->current_text_ptr += text_size;
1429 }
1430 if (!(png_ptr->current_text_left))
1431 {
1432 png_textp text_ptr;
1433 png_charp text;
1434 png_charp key;
1435 int ret;
1436 png_size_t text_size, key_size;
1437
1438 if (png_ptr->buffer_size < 4)
1439 {
1440 png_push_save_buffer(png_ptr);
1441 return;
1442 }
1443
1444 png_push_crc_finish(png_ptr);
1445
1446 key = png_ptr->current_text;
1447
1448 for (text = key; *text; text++)
1449 /* Empty loop */ ;
1450
1451 /* zTXt can't have zero text */
1452 if (text >= key + png_ptr->current_text_size)
1453 {
1454 png_ptr->current_text = NULL;
1455 png_free(png_ptr, key);
1456 return;
1457 }
1458
1459 text++;
1460
1461 if (*text != PNG_TEXT_COMPRESSION_zTXt) /* Check compression byte */
1462 {
1463 png_ptr->current_text = NULL;
1464 png_free(png_ptr, key);
1465 return;
1466 }
1467
1468 text++;
1469
1470 png_ptr->zstream.next_in = (png_bytep)text;
1471 png_ptr->zstream.avail_in = (uInt)(png_ptr->current_text_size -
1472 (text - key));
1473 png_ptr->zstream.next_out = png_ptr->zbuf;
1474 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
1475
1476 key_size = text - key;
1477 text_size = 0;
1478 text = NULL;
1479 ret = Z_STREAM_END;
1480
1481 while (png_ptr->zstream.avail_in)
1482 {
1483 ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
1484 if (ret != Z_OK && ret != Z_STREAM_END)
1485 {
1486 inflateReset(&png_ptr->zstream);
1487 png_ptr->zstream.avail_in = 0;
1488 png_ptr->current_text = NULL;
1489 png_free(png_ptr, key);
1490 png_free(png_ptr, text);
1491 return;
1492 }
1493
1494 if (!(png_ptr->zstream.avail_out) || ret == Z_STREAM_END)
1495 {
1496 if (text == NULL)
1497 {
1498 text = (png_charp)png_malloc(png_ptr,
1499 (png_ptr->zbuf_size
1500 - png_ptr->zstream.avail_out + key_size + 1));
1501
1502 png_memcpy(text + key_size, png_ptr->zbuf,
1503 png_ptr->zbuf_size - png_ptr->zstream.avail_out);
1504
1505 png_memcpy(text, key, key_size);
1506
1507 text_size = key_size + png_ptr->zbuf_size -
1508 png_ptr->zstream.avail_out;
1509
1510 *(text + text_size) = '\0';
1511 }
1512
1513 else
1514 {
1515 png_charp tmp;
1516
1517 tmp = text;
1518 text = (png_charp)png_malloc(png_ptr, text_size +
1519 (png_ptr->zbuf_size
1520 - png_ptr->zstream.avail_out + 1));
1521
1522 png_memcpy(text, tmp, text_size);
1523 png_free(png_ptr, tmp);
1524
1525 png_memcpy(text + text_size, png_ptr->zbuf,
1526 png_ptr->zbuf_size - png_ptr->zstream.avail_out);
1527
1528 text_size += png_ptr->zbuf_size - png_ptr->zstream.avail_out;
1529 *(text + text_size) = '\0';
1530 }
1531
1532 if (ret != Z_STREAM_END)
1533 {
1534 png_ptr->zstream.next_out = png_ptr->zbuf;
1535 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
1536 }
1537 }
1538 else
1539 {
1540 break;
1541 }
1542
1543 if (ret == Z_STREAM_END)
1544 break;
1545 }
1546
1547 inflateReset(&png_ptr->zstream);
1548 png_ptr->zstream.avail_in = 0;
1549
1550 if (ret != Z_STREAM_END)
1551 {
1552 png_ptr->current_text = NULL;
1553 png_free(png_ptr, key);
1554 png_free(png_ptr, text);
1555 return;
1556 }
1557
1558 png_ptr->current_text = NULL;
1559 png_free(png_ptr, key);
1560 key = text;
1561 text += key_size;
1562
1563 text_ptr = (png_textp)png_malloc(png_ptr,
1564 png_sizeof(png_text));
1565 text_ptr->compression = PNG_TEXT_COMPRESSION_zTXt;
1566 text_ptr->key = key;
1567 text_ptr->itxt_length = 0;
1568 text_ptr->lang = NULL;
1569 text_ptr->lang_key = NULL;
1570 text_ptr->text = text;
1571
1572 ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
1573
1574 png_free(png_ptr, key);
1575 png_free(png_ptr, text_ptr);
1576
1577 if (ret)
1578 png_warning(png_ptr, "Insufficient memory to store text chunk");
1579 }
1580 }
1581 #endif
1582
1583 #ifdef PNG_READ_iTXt_SUPPORTED
1584 void /* PRIVATE */
1585 png_push_handle_iTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
1586 length)
1587 {
1588 if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
1589 {
1590 PNG_UNUSED(info_ptr) /* To quiet some compiler warnings */
1591 png_error(png_ptr, "Out of place iTXt");
1592 /*NOT REACHED*/
1593 }
1594
1595 #ifdef PNG_MAX_MALLOC_64K
1596 png_ptr->skip_length = 0; /* This may not be necessary */
1597
1598 if (length > (png_uint_32)65535L) /* Can't hold entire string in memory */
1599 {
1600 png_warning(png_ptr, "iTXt chunk too large to fit in memory");
1601 png_ptr->skip_length = length - (png_uint_32)65535L;
1602 length = (png_uint_32)65535L;
1603 }
1604 #endif
1605
1606 png_ptr->current_text = (png_charp)png_malloc(png_ptr,
1607 (png_size_t)(length + 1));
1608 png_ptr->current_text[length] = '\0';
1609 png_ptr->current_text_ptr = png_ptr->current_text;
1610 png_ptr->current_text_size = (png_size_t)length;
1611 png_ptr->current_text_left = (png_size_t)length;
1612 png_ptr->process_mode = PNG_READ_iTXt_MODE;
1613 }
1614
1615 void /* PRIVATE */
1616 png_push_read_iTXt(png_structp png_ptr, png_infop info_ptr)
1617 {
1618
1619 if (png_ptr->buffer_size && png_ptr->current_text_left)
1620 {
1621 png_size_t text_size;
1622
1623 if (png_ptr->buffer_size < png_ptr->current_text_left)
1624 text_size = png_ptr->buffer_size;
1625
1626 else
1627 text_size = png_ptr->current_text_left;
1628
1629 png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
1630 png_ptr->current_text_left -= text_size;
1631 png_ptr->current_text_ptr += text_size;
1632 }
1633
1634 if (!(png_ptr->current_text_left))
1635 {
1636 png_textp text_ptr;
1637 png_charp key;
1638 int comp_flag;
1639 png_charp lang;
1640 png_charp lang_key;
1641 png_charp text;
1642 int ret;
1643
1644 if (png_ptr->buffer_size < 4)
1645 {
1646 png_push_save_buffer(png_ptr);
1647 return;
1648 }
1649
1650 png_push_crc_finish(png_ptr);
1651
1652 #ifdef PNG_MAX_MALLOC_64K
1653 if (png_ptr->skip_length)
1654 return;
1655 #endif
1656
1657 key = png_ptr->current_text;
1658
1659 for (lang = key; *lang; lang++)
1660 /* Empty loop */ ;
1661
1662 if (lang < key + png_ptr->current_text_size - 3)
1663 lang++;
1664
1665 comp_flag = *lang++;
1666 lang++; /* Skip comp_type, always zero */
1667
1668 for (lang_key = lang; *lang_key; lang_key++)
1669 /* Empty loop */ ;
1670
1671 lang_key++; /* Skip NUL separator */
1672
1673 text=lang_key;
1674
1675 if (lang_key < key + png_ptr->current_text_size - 1)
1676 {
1677 for (; *text; text++)
1678 /* Empty loop */ ;
1679 }
1680
1681 if (text < key + png_ptr->current_text_size)
1682 text++;
1683
1684 text_ptr = (png_textp)png_malloc(png_ptr,
1685 png_sizeof(png_text));
1686
1687 text_ptr->compression = comp_flag + 2;
1688 text_ptr->key = key;
1689 text_ptr->lang = lang;
1690 text_ptr->lang_key = lang_key;
1691 text_ptr->text = text;
1692 text_ptr->text_length = 0;
1693 text_ptr->itxt_length = png_strlen(text);
1694
1695 ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
1696
1697 png_ptr->current_text = NULL;
1698
1699 png_free(png_ptr, text_ptr);
1700 if (ret)
1701 png_warning(png_ptr, "Insufficient memory to store iTXt chunk");
1702 }
1703 }
1704 #endif
1705
1706 /* This function is called when we haven't found a handler for this
1707 * chunk. If there isn't a problem with the chunk itself (ie a bad chunk
1708 * name or a critical chunk), the chunk is (currently) silently ignored.
1709 */
1710 void /* PRIVATE */
1711 png_push_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32
1712 length)
1713 {
1714 png_uint_32 skip = 0;
1715
1716 if (!(png_ptr->chunk_name[0] & 0x20))
1717 {
1718 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
1719 if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
1720 PNG_HANDLE_CHUNK_ALWAYS
1721 #ifdef PNG_READ_USER_CHUNKS_SUPPORTED
1722 && png_ptr->read_user_chunk_fn == NULL
1723 #endif
1724 )
1725 #endif
1726 png_chunk_error(png_ptr, "unknown critical chunk");
1727
1728 PNG_UNUSED(info_ptr) /* To quiet some compiler warnings */
1729 }
1730
1731 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
1732 if (png_ptr->flags & PNG_FLAG_KEEP_UNKNOWN_CHUNKS)
1733 {
1734 #ifdef PNG_MAX_MALLOC_64K
1735 if (length > (png_uint_32)65535L)
1736 {
1737 png_warning(png_ptr, "unknown chunk too large to fit in memory");
1738 skip = length - (png_uint_32)65535L;
1739 length = (png_uint_32)65535L;
1740 }
1741 #endif
1742 png_memcpy((png_charp)png_ptr->unknown_chunk.name,
1743 (png_charp)png_ptr->chunk_name,
1744 png_sizeof(png_ptr->unknown_chunk.name));
1745 png_ptr->unknown_chunk.name[png_sizeof(png_ptr->unknown_chunk.name) - 1]
1746 = '\0';
1747
1748 png_ptr->unknown_chunk.size = (png_size_t)length;
1749
1750 if (length == 0)
1751 png_ptr->unknown_chunk.data = NULL;
1752
1753 else
1754 {
1755 png_ptr->unknown_chunk.data = (png_bytep)png_malloc(png_ptr,
1756 (png_size_t)length);
1757 png_crc_read(png_ptr, (png_bytep)png_ptr->unknown_chunk.data, length);
1758 }
1759
1760 #ifdef PNG_READ_USER_CHUNKS_SUPPORTED
1761 if (png_ptr->read_user_chunk_fn != NULL)
1762 {
1763 /* Callback to user unknown chunk handler */
1764 int ret;
1765 ret = (*(png_ptr->read_user_chunk_fn))
1766 (png_ptr, &png_ptr->unknown_chunk);
1767
1768 if (ret < 0)
1769 png_chunk_error(png_ptr, "error in user chunk");
1770
1771 if (ret == 0)
1772 {
1773 if (!(png_ptr->chunk_name[0] & 0x20))
1774 if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
1775 PNG_HANDLE_CHUNK_ALWAYS)
1776 png_chunk_error(png_ptr, "unknown critical chunk");
1777 png_set_unknown_chunks(png_ptr, info_ptr,
1778 &png_ptr->unknown_chunk, 1);
1779 }
1780 }
1781
1782 else
1783 #endif
1784 png_set_unknown_chunks(png_ptr, info_ptr, &png_ptr->unknown_chunk, 1);
1785 png_free(png_ptr, png_ptr->unknown_chunk.data);
1786 png_ptr->unknown_chunk.data = NULL;
1787 }
1788
1789 else
1790 #endif
1791 skip=length;
1792 png_push_crc_skip(png_ptr, skip);
1793 }
1794
1795 void /* PRIVATE */
1796 png_push_have_info(png_structp png_ptr, png_infop info_ptr)
1797 {
1798 if (png_ptr->info_fn != NULL)
1799 (*(png_ptr->info_fn))(png_ptr, info_ptr);
1800 }
1801
1802 void /* PRIVATE */
1803 png_push_have_end(png_structp png_ptr, png_infop info_ptr)
1804 {
1805 if (png_ptr->end_fn != NULL)
1806 (*(png_ptr->end_fn))(png_ptr, info_ptr);
1807 }
1808
1809 void /* PRIVATE */
1810 png_push_have_row(png_structp png_ptr, png_bytep row)
1811 {
1812 if (png_ptr->row_fn != NULL)
1813 (*(png_ptr->row_fn))(png_ptr, row, png_ptr->row_number,
1814 (int)png_ptr->pass);
1815 }
1816
1817 void PNGAPI
1818 png_progressive_combine_row (png_structp png_ptr, png_bytep old_row,
1819 png_const_bytep new_row)
1820 {
1821 PNG_CONST int FARDATA png_pass_dsp_mask[7] =
1822 {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
1823
1824 if (png_ptr == NULL)
1825 return;
1826
1827 if (new_row != NULL) /* new_row must == png_ptr->row_buf here. */
1828 png_combine_row(png_ptr, old_row, png_pass_dsp_mask[png_ptr->pass]);
1829 }
1830
1831 void PNGAPI
1832 png_set_progressive_read_fn(png_structp png_ptr, png_voidp progressive_ptr,
1833 png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,
1834 png_progressive_end_ptr end_fn)
1835 {
1836 if (png_ptr == NULL)
1837 return;
1838
1839 png_ptr->info_fn = info_fn;
1840 png_ptr->row_fn = row_fn;
1841 png_ptr->end_fn = end_fn;
1842
1843 png_set_read_fn(png_ptr, progressive_ptr, png_push_fill_buffer);
1844 }
1845
1846 png_voidp PNGAPI
1847 png_get_progressive_ptr(png_const_structp png_ptr)
1848 {
1849 if (png_ptr == NULL)
1850 return (NULL);
1851
1852 return png_ptr->io_ptr;
1853 }
1854 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
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