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1
2/* pngpread.c - read a png file in push mode
3 *
4 * libpng version 1.2.7 - September 12, 2004
5 * For conditions of distribution and use, see copyright notice in png.h
6 * Copyright (c) 1998-2004 Glenn Randers-Pehrson
7 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
8 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
9 */
10
11#define PNG_INTERNAL
12#include "png.h"
13
14#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
15
16/* push model modes */
17#define PNG_READ_SIG_MODE 0
18#define PNG_READ_CHUNK_MODE 1
19#define PNG_READ_IDAT_MODE 2
20#define PNG_SKIP_MODE 3
21#define PNG_READ_tEXt_MODE 4
22#define PNG_READ_zTXt_MODE 5
23#define PNG_READ_DONE_MODE 6
24#define PNG_READ_iTXt_MODE 7
25#define PNG_ERROR_MODE 8
26
27void PNGAPI
28png_process_data(png_structp png_ptr, png_infop info_ptr,
29 png_bytep buffer, png_size_t buffer_size)
30{
31 png_push_restore_buffer(png_ptr, buffer, buffer_size);
32
33 while (png_ptr->buffer_size)
34 {
35 png_process_some_data(png_ptr, info_ptr);
36 }
37}
38
39/* What we do with the incoming data depends on what we were previously
40 * doing before we ran out of data...
41 */
42void /* PRIVATE */
43png_process_some_data(png_structp png_ptr, png_infop info_ptr)
44{
45 switch (png_ptr->process_mode)
46 {
47 case PNG_READ_SIG_MODE:
48 {
49 png_push_read_sig(png_ptr, info_ptr);
50 break;
51 }
52 case PNG_READ_CHUNK_MODE:
53 {
54 png_push_read_chunk(png_ptr, info_ptr);
55 break;
56 }
57 case PNG_READ_IDAT_MODE:
58 {
59 png_push_read_IDAT(png_ptr);
60 break;
61 }
62#if defined(PNG_READ_tEXt_SUPPORTED)
63 case PNG_READ_tEXt_MODE:
64 {
65 png_push_read_tEXt(png_ptr, info_ptr);
66 break;
67 }
68#endif
69#if defined(PNG_READ_zTXt_SUPPORTED)
70 case PNG_READ_zTXt_MODE:
71 {
72 png_push_read_zTXt(png_ptr, info_ptr);
73 break;
74 }
75#endif
76#if defined(PNG_READ_iTXt_SUPPORTED)
77 case PNG_READ_iTXt_MODE:
78 {
79 png_push_read_iTXt(png_ptr, info_ptr);
80 break;
81 }
82#endif
83 case PNG_SKIP_MODE:
84 {
85 png_push_crc_finish(png_ptr);
86 break;
87 }
88 default:
89 {
90 png_ptr->buffer_size = 0;
91 break;
92 }
93 }
94}
95
96/* Read any remaining signature bytes from the stream and compare them with
97 * the correct PNG signature. It is possible that this routine is called
98 * with bytes already read from the signature, either because they have been
99 * checked by the calling application, or because of multiple calls to this
100 * routine.
101 */
102void /* PRIVATE */
103png_push_read_sig(png_structp png_ptr, png_infop info_ptr)
104{
105 png_size_t num_checked = png_ptr->sig_bytes,
106 num_to_check = 8 - num_checked;
107
108 if (png_ptr->buffer_size < num_to_check)
109 {
110 num_to_check = png_ptr->buffer_size;
111 }
112
113 png_push_fill_buffer(png_ptr, &(info_ptr->signature[num_checked]),
114 num_to_check);
115 png_ptr->sig_bytes = (png_byte)(png_ptr->sig_bytes+num_to_check);
116
117 if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
118 {
119 if (num_checked < 4 &&
120 png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
121 png_error(png_ptr, "Not a PNG file");
122 else
123 png_error(png_ptr, "PNG file corrupted by ASCII conversion");
124 }
125 else
126 {
127 if (png_ptr->sig_bytes >= 8)
128 {
129 png_ptr->process_mode = PNG_READ_CHUNK_MODE;
130 }
131 }
132}
133
134void /* PRIVATE */
135png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
136{
137#ifdef PNG_USE_LOCAL_ARRAYS
138 PNG_IHDR;
139 PNG_IDAT;
140 PNG_IEND;
141 PNG_PLTE;
142#if defined(PNG_READ_bKGD_SUPPORTED)
143 PNG_bKGD;
144#endif
145#if defined(PNG_READ_cHRM_SUPPORTED)
146 PNG_cHRM;
147#endif
148#if defined(PNG_READ_gAMA_SUPPORTED)
149 PNG_gAMA;
150#endif
151#if defined(PNG_READ_hIST_SUPPORTED)
152 PNG_hIST;
153#endif
154#if defined(PNG_READ_iCCP_SUPPORTED)
155 PNG_iCCP;
156#endif
157#if defined(PNG_READ_iTXt_SUPPORTED)
158 PNG_iTXt;
159#endif
160#if defined(PNG_READ_oFFs_SUPPORTED)
161 PNG_oFFs;
162#endif
163#if defined(PNG_READ_pCAL_SUPPORTED)
164 PNG_pCAL;
165#endif
166#if defined(PNG_READ_pHYs_SUPPORTED)
167 PNG_pHYs;
168#endif
169#if defined(PNG_READ_sBIT_SUPPORTED)
170 PNG_sBIT;
171#endif
172#if defined(PNG_READ_sCAL_SUPPORTED)
173 PNG_sCAL;
174#endif
175#if defined(PNG_READ_sRGB_SUPPORTED)
176 PNG_sRGB;
177#endif
178#if defined(PNG_READ_sPLT_SUPPORTED)
179 PNG_sPLT;
180#endif
181#if defined(PNG_READ_tEXt_SUPPORTED)
182 PNG_tEXt;
183#endif
184#if defined(PNG_READ_tIME_SUPPORTED)
185 PNG_tIME;
186#endif
187#if defined(PNG_READ_tRNS_SUPPORTED)
188 PNG_tRNS;
189#endif
190#if defined(PNG_READ_zTXt_SUPPORTED)
191 PNG_zTXt;
192#endif
193#endif /* PNG_USE_LOCAL_ARRAYS */
194 /* First we make sure we have enough data for the 4 byte chunk name
195 * and the 4 byte chunk length before proceeding with decoding the
196 * chunk data. To fully decode each of these chunks, we also make
197 * sure we have enough data in the buffer for the 4 byte CRC at the
198 * end of every chunk (except IDAT, which is handled separately).
199 */
200 if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
201 {
202 png_byte chunk_length[4];
203
204 if (png_ptr->buffer_size < 8)
205 {
206 png_push_save_buffer(png_ptr);
207 return;
208 }
209
210 png_push_fill_buffer(png_ptr, chunk_length, 4);
211 png_ptr->push_length = png_get_uint_31(png_ptr,chunk_length);
212 png_reset_crc(png_ptr);
213 png_crc_read(png_ptr, png_ptr->chunk_name, 4);
214 png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
215 }
216
217 if (!png_memcmp(png_ptr->chunk_name, png_IHDR, 4))
218 {
219 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
220 {
221 png_push_save_buffer(png_ptr);
222 return;
223 }
224 png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length);
225 }
226 else if (!png_memcmp(png_ptr->chunk_name, png_IEND, 4))
227 {
228 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
229 {
230 png_push_save_buffer(png_ptr);
231 return;
232 }
233 png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length);
234
235 png_ptr->process_mode = PNG_READ_DONE_MODE;
236 png_push_have_end(png_ptr, info_ptr);
237 }
238#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
239 else if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name))
240 {
241 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
242 {
243 png_push_save_buffer(png_ptr);
244 return;
245 }
246 if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
247 png_ptr->mode |= PNG_HAVE_IDAT;
248 png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length);
249 if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
250 png_ptr->mode |= PNG_HAVE_PLTE;
251 else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
252 {
253 if (!(png_ptr->mode & PNG_HAVE_IHDR))
254 png_error(png_ptr, "Missing IHDR before IDAT");
255 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
256 !(png_ptr->mode & PNG_HAVE_PLTE))
257 png_error(png_ptr, "Missing PLTE before IDAT");
258 }
259 }
260#endif
261 else if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
262 {
263 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
264 {
265 png_push_save_buffer(png_ptr);
266 return;
267 }
268 png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
269 }
270 else if (!png_memcmp(png_ptr->chunk_name, (png_bytep)png_IDAT, 4))
271 {
272 /* If we reach an IDAT chunk, this means we have read all of the
273 * header chunks, and we can start reading the image (or if this
274 * is called after the image has been read - we have an error).
275 */
276 if (!(png_ptr->mode & PNG_HAVE_IHDR))
277 png_error(png_ptr, "Missing IHDR before IDAT");
278 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
279 !(png_ptr->mode & PNG_HAVE_PLTE))
280 png_error(png_ptr, "Missing PLTE before IDAT");
281
282 if (png_ptr->mode & PNG_HAVE_IDAT)
283 {
284 if (png_ptr->push_length == 0)
285 return;
286
287 if (png_ptr->mode & PNG_AFTER_IDAT)
288 png_error(png_ptr, "Too many IDAT's found");
289 }
290
291 png_ptr->idat_size = png_ptr->push_length;
292 png_ptr->mode |= PNG_HAVE_IDAT;
293 png_ptr->process_mode = PNG_READ_IDAT_MODE;
294 png_push_have_info(png_ptr, info_ptr);
295 png_ptr->zstream.avail_out = (uInt)png_ptr->irowbytes;
296 png_ptr->zstream.next_out = png_ptr->row_buf;
297 return;
298 }
299#if defined(PNG_READ_gAMA_SUPPORTED)
300 else if (!png_memcmp(png_ptr->chunk_name, png_gAMA, 4))
301 {
302 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
303 {
304 png_push_save_buffer(png_ptr);
305 return;
306 }
307 png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length);
308 }
309#endif
310#if defined(PNG_READ_sBIT_SUPPORTED)
311 else if (!png_memcmp(png_ptr->chunk_name, png_sBIT, 4))
312 {
313 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
314 {
315 png_push_save_buffer(png_ptr);
316 return;
317 }
318 png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length);
319 }
320#endif
321#if defined(PNG_READ_cHRM_SUPPORTED)
322 else if (!png_memcmp(png_ptr->chunk_name, png_cHRM, 4))
323 {
324 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
325 {
326 png_push_save_buffer(png_ptr);
327 return;
328 }
329 png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length);
330 }
331#endif
332#if defined(PNG_READ_sRGB_SUPPORTED)
333 else if (!png_memcmp(png_ptr->chunk_name, png_sRGB, 4))
334 {
335 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
336 {
337 png_push_save_buffer(png_ptr);
338 return;
339 }
340 png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length);
341 }
342#endif
343#if defined(PNG_READ_iCCP_SUPPORTED)
344 else if (!png_memcmp(png_ptr->chunk_name, png_iCCP, 4))
345 {
346 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
347 {
348 png_push_save_buffer(png_ptr);
349 return;
350 }
351 png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length);
352 }
353#endif
354#if defined(PNG_READ_sPLT_SUPPORTED)
355 else if (!png_memcmp(png_ptr->chunk_name, png_sPLT, 4))
356 {
357 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
358 {
359 png_push_save_buffer(png_ptr);
360 return;
361 }
362 png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length);
363 }
364#endif
365#if defined(PNG_READ_tRNS_SUPPORTED)
366 else if (!png_memcmp(png_ptr->chunk_name, png_tRNS, 4))
367 {
368 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
369 {
370 png_push_save_buffer(png_ptr);
371 return;
372 }
373 png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length);
374 }
375#endif
376#if defined(PNG_READ_bKGD_SUPPORTED)
377 else if (!png_memcmp(png_ptr->chunk_name, png_bKGD, 4))
378 {
379 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
380 {
381 png_push_save_buffer(png_ptr);
382 return;
383 }
384 png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length);
385 }
386#endif
387#if defined(PNG_READ_hIST_SUPPORTED)
388 else if (!png_memcmp(png_ptr->chunk_name, png_hIST, 4))
389 {
390 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
391 {
392 png_push_save_buffer(png_ptr);
393 return;
394 }
395 png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length);
396 }
397#endif
398#if defined(PNG_READ_pHYs_SUPPORTED)
399 else if (!png_memcmp(png_ptr->chunk_name, png_pHYs, 4))
400 {
401 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
402 {
403 png_push_save_buffer(png_ptr);
404 return;
405 }
406 png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length);
407 }
408#endif
409#if defined(PNG_READ_oFFs_SUPPORTED)
410 else if (!png_memcmp(png_ptr->chunk_name, png_oFFs, 4))
411 {
412 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
413 {
414 png_push_save_buffer(png_ptr);
415 return;
416 }
417 png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length);
418 }
419#endif
420#if defined(PNG_READ_pCAL_SUPPORTED)
421 else if (!png_memcmp(png_ptr->chunk_name, png_pCAL, 4))
422 {
423 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
424 {
425 png_push_save_buffer(png_ptr);
426 return;
427 }
428 png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length);
429 }
430#endif
431#if defined(PNG_READ_sCAL_SUPPORTED)
432 else if (!png_memcmp(png_ptr->chunk_name, png_sCAL, 4))
433 {
434 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
435 {
436 png_push_save_buffer(png_ptr);
437 return;
438 }
439 png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length);
440 }
441#endif
442#if defined(PNG_READ_tIME_SUPPORTED)
443 else if (!png_memcmp(png_ptr->chunk_name, png_tIME, 4))
444 {
445 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
446 {
447 png_push_save_buffer(png_ptr);
448 return;
449 }
450 png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length);
451 }
452#endif
453#if defined(PNG_READ_tEXt_SUPPORTED)
454 else if (!png_memcmp(png_ptr->chunk_name, png_tEXt, 4))
455 {
456 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
457 {
458 png_push_save_buffer(png_ptr);
459 return;
460 }
461 png_push_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length);
462 }
463#endif
464#if defined(PNG_READ_zTXt_SUPPORTED)
465 else if (!png_memcmp(png_ptr->chunk_name, png_zTXt, 4))
466 {
467 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
468 {
469 png_push_save_buffer(png_ptr);
470 return;
471 }
472 png_push_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
473 }
474#endif
475#if defined(PNG_READ_iTXt_SUPPORTED)
476 else if (!png_memcmp(png_ptr->chunk_name, png_iTXt, 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 png_push_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
484 }
485#endif
486 else
487 {
488 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
489 {
490 png_push_save_buffer(png_ptr);
491 return;
492 }
493 png_push_handle_unknown(png_ptr, info_ptr, png_ptr->push_length);
494 }
495
496 png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
497}
498
499void /* PRIVATE */
500png_push_crc_skip(png_structp png_ptr, png_uint_32 skip)
501{
502 png_ptr->process_mode = PNG_SKIP_MODE;
503 png_ptr->skip_length = skip;
504}
505
506void /* PRIVATE */
507png_push_crc_finish(png_structp png_ptr)
508{
509 if (png_ptr->skip_length && png_ptr->save_buffer_size)
510 {
511 png_size_t save_size;
512
513 if (png_ptr->skip_length < (png_uint_32)png_ptr->save_buffer_size)
514 save_size = (png_size_t)png_ptr->skip_length;
515 else
516 save_size = png_ptr->save_buffer_size;
517
518 png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
519
520 png_ptr->skip_length -= save_size;
521 png_ptr->buffer_size -= save_size;
522 png_ptr->save_buffer_size -= save_size;
523 png_ptr->save_buffer_ptr += save_size;
524 }
525 if (png_ptr->skip_length && png_ptr->current_buffer_size)
526 {
527 png_size_t save_size;
528
529 if (png_ptr->skip_length < (png_uint_32)png_ptr->current_buffer_size)
530 save_size = (png_size_t)png_ptr->skip_length;
531 else
532 save_size = png_ptr->current_buffer_size;
533
534 png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
535
536 png_ptr->skip_length -= save_size;
537 png_ptr->buffer_size -= save_size;
538 png_ptr->current_buffer_size -= save_size;
539 png_ptr->current_buffer_ptr += save_size;
540 }
541 if (!png_ptr->skip_length)
542 {
543 if (png_ptr->buffer_size < 4)
544 {
545 png_push_save_buffer(png_ptr);
546 return;
547 }
548
549 png_crc_finish(png_ptr, 0);
550 png_ptr->process_mode = PNG_READ_CHUNK_MODE;
551 }
552}
553
554void PNGAPI
555png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
556{
557 png_bytep ptr;
558
559 ptr = buffer;
560 if (png_ptr->save_buffer_size)
561 {
562 png_size_t save_size;
563
564 if (length < png_ptr->save_buffer_size)
565 save_size = length;
566 else
567 save_size = png_ptr->save_buffer_size;
568
569 png_memcpy(ptr, png_ptr->save_buffer_ptr, save_size);
570 length -= save_size;
571 ptr += save_size;
572 png_ptr->buffer_size -= save_size;
573 png_ptr->save_buffer_size -= save_size;
574 png_ptr->save_buffer_ptr += save_size;
575 }
576 if (length && png_ptr->current_buffer_size)
577 {
578 png_size_t save_size;
579
580 if (length < png_ptr->current_buffer_size)
581 save_size = length;
582 else
583 save_size = png_ptr->current_buffer_size;
584
585 png_memcpy(ptr, png_ptr->current_buffer_ptr, save_size);
586 png_ptr->buffer_size -= save_size;
587 png_ptr->current_buffer_size -= save_size;
588 png_ptr->current_buffer_ptr += save_size;
589 }
590}
591
592void /* PRIVATE */
593png_push_save_buffer(png_structp png_ptr)
594{
595 if (png_ptr->save_buffer_size)
596 {
597 if (png_ptr->save_buffer_ptr != png_ptr->save_buffer)
598 {
599 png_size_t i,istop;
600 png_bytep sp;
601 png_bytep dp;
602
603 istop = png_ptr->save_buffer_size;
604 for (i = 0, sp = png_ptr->save_buffer_ptr, dp = png_ptr->save_buffer;
605 i < istop; i++, sp++, dp++)
606 {
607 *dp = *sp;
608 }
609 }
610 }
611 if (png_ptr->save_buffer_size + png_ptr->current_buffer_size >
612 png_ptr->save_buffer_max)
613 {
614 png_size_t new_max;
615 png_bytep old_buffer;
616
617 if (png_ptr->save_buffer_size > PNG_SIZE_MAX -
618 (png_ptr->current_buffer_size + 256))
619 {
620 png_error(png_ptr, "Potential overflow of save_buffer");
621 }
622 new_max = png_ptr->save_buffer_size + png_ptr->current_buffer_size + 256;
623 old_buffer = png_ptr->save_buffer;
624 png_ptr->save_buffer = (png_bytep)png_malloc(png_ptr,
625 (png_uint_32)new_max);
626 png_memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size);
627 png_free(png_ptr, old_buffer);
628 png_ptr->save_buffer_max = new_max;
629 }
630 if (png_ptr->current_buffer_size)
631 {
632 png_memcpy(png_ptr->save_buffer + png_ptr->save_buffer_size,
633 png_ptr->current_buffer_ptr, png_ptr->current_buffer_size);
634 png_ptr->save_buffer_size += png_ptr->current_buffer_size;
635 png_ptr->current_buffer_size = 0;
636 }
637 png_ptr->save_buffer_ptr = png_ptr->save_buffer;
638 png_ptr->buffer_size = 0;
639}
640
641void /* PRIVATE */
642png_push_restore_buffer(png_structp png_ptr, png_bytep buffer,
643 png_size_t buffer_length)
644{
645 png_ptr->current_buffer = buffer;
646 png_ptr->current_buffer_size = buffer_length;
647 png_ptr->buffer_size = buffer_length + png_ptr->save_buffer_size;
648 png_ptr->current_buffer_ptr = png_ptr->current_buffer;
649}
650
651void /* PRIVATE */
652png_push_read_IDAT(png_structp png_ptr)
653{
654#ifdef PNG_USE_LOCAL_ARRAYS
655 PNG_IDAT;
656#endif
657 if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
658 {
659 png_byte chunk_length[4];
660
661 if (png_ptr->buffer_size < 8)
662 {
663 png_push_save_buffer(png_ptr);
664 return;
665 }
666
667 png_push_fill_buffer(png_ptr, chunk_length, 4);
668 png_ptr->push_length = png_get_uint_31(png_ptr,chunk_length);
669 png_reset_crc(png_ptr);
670 png_crc_read(png_ptr, png_ptr->chunk_name, 4);
671 png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
672
673 if (png_memcmp(png_ptr->chunk_name, (png_bytep)png_IDAT, 4))
674 {
675 png_ptr->process_mode = PNG_READ_CHUNK_MODE;
676 if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
677 png_error(png_ptr, "Not enough compressed data");
678 return;
679 }
680
681 png_ptr->idat_size = png_ptr->push_length;
682 }
683 if (png_ptr->idat_size && png_ptr->save_buffer_size)
684 {
685 png_size_t save_size;
686
687 if (png_ptr->idat_size < (png_uint_32)png_ptr->save_buffer_size)
688 {
689 save_size = (png_size_t)png_ptr->idat_size;
690 /* check for overflow */
691 if((png_uint_32)save_size != png_ptr->idat_size)
692 png_error(png_ptr, "save_size overflowed in pngpread");
693 }
694 else
695 save_size = png_ptr->save_buffer_size;
696
697 png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
698 if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
699 png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size);
700 png_ptr->idat_size -= save_size;
701 png_ptr->buffer_size -= save_size;
702 png_ptr->save_buffer_size -= save_size;
703 png_ptr->save_buffer_ptr += save_size;
704 }
705 if (png_ptr->idat_size && png_ptr->current_buffer_size)
706 {
707 png_size_t save_size;
708
709 if (png_ptr->idat_size < (png_uint_32)png_ptr->current_buffer_size)
710 {
711 save_size = (png_size_t)png_ptr->idat_size;
712 /* check for overflow */
713 if((png_uint_32)save_size != png_ptr->idat_size)
714 png_error(png_ptr, "save_size overflowed in pngpread");
715 }
716 else
717 save_size = png_ptr->current_buffer_size;
718
719 png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
720 if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
721 png_process_IDAT_data(png_ptr, png_ptr->current_buffer_ptr, save_size);
722
723 png_ptr->idat_size -= save_size;
724 png_ptr->buffer_size -= save_size;
725 png_ptr->current_buffer_size -= save_size;
726 png_ptr->current_buffer_ptr += save_size;
727 }
728 if (!png_ptr->idat_size)
729 {
730 if (png_ptr->buffer_size < 4)
731 {
732 png_push_save_buffer(png_ptr);
733 return;
734 }
735
736 png_crc_finish(png_ptr, 0);
737 png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
738 png_ptr->mode |= PNG_AFTER_IDAT;
739 }
740}
741
742void /* PRIVATE */
743png_process_IDAT_data(png_structp png_ptr, png_bytep buffer,
744 png_size_t buffer_length)
745{
746 int ret;
747
748 if ((png_ptr->flags & PNG_FLAG_ZLIB_FINISHED) && buffer_length)
749 png_error(png_ptr, "Extra compression data");
750
751 png_ptr->zstream.next_in = buffer;
752 png_ptr->zstream.avail_in = (uInt)buffer_length;
753 for(;;)
754 {
755 ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
756 if (ret != Z_OK)
757 {
758 if (ret == Z_STREAM_END)
759 {
760 if (png_ptr->zstream.avail_in)
761 png_error(png_ptr, "Extra compressed data");
762 if (!(png_ptr->zstream.avail_out))
763 {
764 png_push_process_row(png_ptr);
765 }
766
767 png_ptr->mode |= PNG_AFTER_IDAT;
768 png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
769 break;
770 }
771 else if (ret == Z_BUF_ERROR)
772 break;
773 else
774 png_error(png_ptr, "Decompression Error");
775 }
776 if (!(png_ptr->zstream.avail_out))
777 {
778 if ((
779#if defined(PNG_READ_INTERLACING_SUPPORTED)
780 png_ptr->interlaced && png_ptr->pass > 6) ||
781 (!png_ptr->interlaced &&
782#endif
783 png_ptr->row_number == png_ptr->num_rows))
784 {
785 if (png_ptr->zstream.avail_in)
786 png_warning(png_ptr, "Too much data in IDAT chunks");
787 png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
788 break;
789 }
790 png_push_process_row(png_ptr);
791 png_ptr->zstream.avail_out = (uInt)png_ptr->irowbytes;
792 png_ptr->zstream.next_out = png_ptr->row_buf;
793 }
794 else
795 break;
796 }
797}
798
799void /* PRIVATE */
800png_push_process_row(png_structp png_ptr)
801{
802 png_ptr->row_info.color_type = png_ptr->color_type;
803 png_ptr->row_info.width = png_ptr->iwidth;
804 png_ptr->row_info.channels = png_ptr->channels;
805 png_ptr->row_info.bit_depth = png_ptr->bit_depth;
806 png_ptr->row_info.pixel_depth = png_ptr->pixel_depth;
807
808 png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth,
809 png_ptr->row_info.width);
810
811 png_read_filter_row(png_ptr, &(png_ptr->row_info),
812 png_ptr->row_buf + 1, png_ptr->prev_row + 1,
813 (int)(png_ptr->row_buf[0]));
814
815 png_memcpy_check(png_ptr, png_ptr->prev_row, png_ptr->row_buf,
816 png_ptr->rowbytes + 1);
817
818 if (png_ptr->transformations)
819 png_do_read_transformations(png_ptr);
820
821#if defined(PNG_READ_INTERLACING_SUPPORTED)
822 /* blow up interlaced rows to full size */
823 if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
824 {
825 if (png_ptr->pass < 6)
826/* old interface (pre-1.0.9):
827 png_do_read_interlace(&(png_ptr->row_info),
828 png_ptr->row_buf + 1, png_ptr->pass, png_ptr->transformations);
829 */
830 png_do_read_interlace(png_ptr);
831
832 switch (png_ptr->pass)
833 {
834 case 0:
835 {
836 int i;
837 for (i = 0; i < 8 && png_ptr->pass == 0; i++)
838 {
839 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
840 png_read_push_finish_row(png_ptr); /* updates png_ptr->pass */
841 }
842 if (png_ptr->pass == 2) /* pass 1 might be empty */
843 {
844 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
845 {
846 png_push_have_row(png_ptr, png_bytep_NULL);
847 png_read_push_finish_row(png_ptr);
848 }
849 }
850 if (png_ptr->pass == 4 && png_ptr->height <= 4)
851 {
852 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
853 {
854 png_push_have_row(png_ptr, png_bytep_NULL);
855 png_read_push_finish_row(png_ptr);
856 }
857 }
858 if (png_ptr->pass == 6 && png_ptr->height <= 4)
859 {
860 png_push_have_row(png_ptr, png_bytep_NULL);
861 png_read_push_finish_row(png_ptr);
862 }
863 break;
864 }
865 case 1:
866 {
867 int i;
868 for (i = 0; i < 8 && png_ptr->pass == 1; i++)
869 {
870 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
871 png_read_push_finish_row(png_ptr);
872 }
873 if (png_ptr->pass == 2) /* skip top 4 generated rows */
874 {
875 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
876 {
877 png_push_have_row(png_ptr, png_bytep_NULL);
878 png_read_push_finish_row(png_ptr);
879 }
880 }
881 break;
882 }
883 case 2:
884 {
885 int i;
886 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
887 {
888 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
889 png_read_push_finish_row(png_ptr);
890 }
891 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
892 {
893 png_push_have_row(png_ptr, png_bytep_NULL);
894 png_read_push_finish_row(png_ptr);
895 }
896 if (png_ptr->pass == 4) /* pass 3 might be empty */
897 {
898 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
899 {
900 png_push_have_row(png_ptr, png_bytep_NULL);
901 png_read_push_finish_row(png_ptr);
902 }
903 }
904 break;
905 }
906 case 3:
907 {
908 int i;
909 for (i = 0; i < 4 && png_ptr->pass == 3; i++)
910 {
911 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
912 png_read_push_finish_row(png_ptr);
913 }
914 if (png_ptr->pass == 4) /* skip top two generated rows */
915 {
916 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
917 {
918 png_push_have_row(png_ptr, png_bytep_NULL);
919 png_read_push_finish_row(png_ptr);
920 }
921 }
922 break;
923 }
924 case 4:
925 {
926 int i;
927 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
928 {
929 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
930 png_read_push_finish_row(png_ptr);
931 }
932 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
933 {
934 png_push_have_row(png_ptr, png_bytep_NULL);
935 png_read_push_finish_row(png_ptr);
936 }
937 if (png_ptr->pass == 6) /* pass 5 might be empty */
938 {
939 png_push_have_row(png_ptr, png_bytep_NULL);
940 png_read_push_finish_row(png_ptr);
941 }
942 break;
943 }
944 case 5:
945 {
946 int i;
947 for (i = 0; i < 2 && png_ptr->pass == 5; i++)
948 {
949 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
950 png_read_push_finish_row(png_ptr);
951 }
952 if (png_ptr->pass == 6) /* skip top generated row */
953 {
954 png_push_have_row(png_ptr, png_bytep_NULL);
955 png_read_push_finish_row(png_ptr);
956 }
957 break;
958 }
959 case 6:
960 {
961 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
962 png_read_push_finish_row(png_ptr);
963 if (png_ptr->pass != 6)
964 break;
965 png_push_have_row(png_ptr, png_bytep_NULL);
966 png_read_push_finish_row(png_ptr);
967 }
968 }
969 }
970 else
971#endif
972 {
973 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
974 png_read_push_finish_row(png_ptr);
975 }
976}
977
978void /* PRIVATE */
979png_read_push_finish_row(png_structp png_ptr)
980{
981#ifdef PNG_USE_LOCAL_ARRAYS
982 /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
983
984 /* start of interlace block */
985 const int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
986
987 /* offset to next interlace block */
988 const int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
989
990 /* start of interlace block in the y direction */
991 const int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
992
993 /* offset to next interlace block in the y direction */
994 const int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
995
996 /* Width of interlace block. This is not currently used - if you need
997 * it, uncomment it here and in png.h
998 const int FARDATA png_pass_width[] = {8, 4, 4, 2, 2, 1, 1};
999 */
1000
1001 /* Height of interlace block. This is not currently used - if you need
1002 * it, uncomment it here and in png.h
1003 const int FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
1004 */
1005#endif
1006
1007 png_ptr->row_number++;
1008 if (png_ptr->row_number < png_ptr->num_rows)
1009 return;
1010
1011 if (png_ptr->interlaced)
1012 {
1013 png_ptr->row_number = 0;
1014 png_memset_check(png_ptr, png_ptr->prev_row, 0,
1015 png_ptr->rowbytes + 1);
1016 do
1017 {
1018 png_ptr->pass++;
1019 if ((png_ptr->pass == 1 && png_ptr->width < 5) ||
1020 (png_ptr->pass == 3 && png_ptr->width < 3) ||
1021 (png_ptr->pass == 5 && png_ptr->width < 2))
1022 png_ptr->pass++;
1023
1024 if (png_ptr->pass > 7)
1025 png_ptr->pass--;
1026 if (png_ptr->pass >= 7)
1027 break;
1028
1029 png_ptr->iwidth = (png_ptr->width +
1030 png_pass_inc[png_ptr->pass] - 1 -
1031 png_pass_start[png_ptr->pass]) /
1032 png_pass_inc[png_ptr->pass];
1033
1034 png_ptr->irowbytes = PNG_ROWBYTES(png_ptr->pixel_depth,
1035 png_ptr->iwidth) + 1;
1036
1037 if (png_ptr->transformations & PNG_INTERLACE)
1038 break;
1039
1040 png_ptr->num_rows = (png_ptr->height +
1041 png_pass_yinc[png_ptr->pass] - 1 -
1042 png_pass_ystart[png_ptr->pass]) /
1043 png_pass_yinc[png_ptr->pass];
1044
1045 } while (png_ptr->iwidth == 0 || png_ptr->num_rows == 0);
1046 }
1047}
1048
1049#if defined(PNG_READ_tEXt_SUPPORTED)
1050void /* PRIVATE */
1051png_push_handle_tEXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
1052 length)
1053{
1054 if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
1055 {
1056 png_error(png_ptr, "Out of place tEXt");
1057 /* to quiet some compiler warnings */
1058 if(info_ptr == NULL) return;
1059 }
1060
1061#ifdef PNG_MAX_MALLOC_64K
1062 png_ptr->skip_length = 0; /* This may not be necessary */
1063
1064 if (length > (png_uint_32)65535L) /* Can't hold entire string in memory */
1065 {
1066 png_warning(png_ptr, "tEXt chunk too large to fit in memory");
1067 png_ptr->skip_length = length - (png_uint_32)65535L;
1068 length = (png_uint_32)65535L;
1069 }
1070#endif
1071
1072 png_ptr->current_text = (png_charp)png_malloc(png_ptr,
1073 (png_uint_32)(length+1));
1074 png_ptr->current_text[length] = '\0';
1075 png_ptr->current_text_ptr = png_ptr->current_text;
1076 png_ptr->current_text_size = (png_size_t)length;
1077 png_ptr->current_text_left = (png_size_t)length;
1078 png_ptr->process_mode = PNG_READ_tEXt_MODE;
1079}
1080
1081void /* PRIVATE */
1082png_push_read_tEXt(png_structp png_ptr, png_infop info_ptr)
1083{
1084 if (png_ptr->buffer_size && png_ptr->current_text_left)
1085 {
1086 png_size_t text_size;
1087
1088 if (png_ptr->buffer_size < png_ptr->current_text_left)
1089 text_size = png_ptr->buffer_size;
1090 else
1091 text_size = png_ptr->current_text_left;
1092 png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
1093 png_ptr->current_text_left -= text_size;
1094 png_ptr->current_text_ptr += text_size;
1095 }
1096 if (!(png_ptr->current_text_left))
1097 {
1098 png_textp text_ptr;
1099 png_charp text;
1100 png_charp key;
1101 int ret;
1102
1103 if (png_ptr->buffer_size < 4)
1104 {
1105 png_push_save_buffer(png_ptr);
1106 return;
1107 }
1108
1109 png_push_crc_finish(png_ptr);
1110
1111#if defined(PNG_MAX_MALLOC_64K)
1112 if (png_ptr->skip_length)
1113 return;
1114#endif
1115
1116 key = png_ptr->current_text;
1117
1118 for (text = key; *text; text++)
1119 /* empty loop */ ;
1120
1121 if (text != key + png_ptr->current_text_size)
1122 text++;
1123
1124 text_ptr = (png_textp)png_malloc(png_ptr,
1125 (png_uint_32)png_sizeof(png_text));
1126 text_ptr->compression = PNG_TEXT_COMPRESSION_NONE;
1127 text_ptr->key = key;
1128#ifdef PNG_iTXt_SUPPORTED
1129 text_ptr->lang = NULL;
1130 text_ptr->lang_key = NULL;
1131#endif
1132 text_ptr->text = text;
1133
1134 ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
1135
1136 png_free(png_ptr, key);
1137 png_free(png_ptr, text_ptr);
1138 png_ptr->current_text = NULL;
1139
1140 if (ret)
1141 png_warning(png_ptr, "Insufficient memory to store text chunk.");
1142 }
1143}
1144#endif
1145
1146#if defined(PNG_READ_zTXt_SUPPORTED)
1147void /* PRIVATE */
1148png_push_handle_zTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
1149 length)
1150{
1151 if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
1152 {
1153 png_error(png_ptr, "Out of place zTXt");
1154 /* to quiet some compiler warnings */
1155 if(info_ptr == NULL) return;
1156 }
1157
1158#ifdef PNG_MAX_MALLOC_64K
1159 /* We can't handle zTXt chunks > 64K, since we don't have enough space
1160 * to be able to store the uncompressed data. Actually, the threshold
1161 * is probably around 32K, but it isn't as definite as 64K is.
1162 */
1163 if (length > (png_uint_32)65535L)
1164 {
1165 png_warning(png_ptr, "zTXt chunk too large to fit in memory");
1166 png_push_crc_skip(png_ptr, length);
1167 return;
1168 }
1169#endif
1170
1171 png_ptr->current_text = (png_charp)png_malloc(png_ptr,
1172 (png_uint_32)(length+1));
1173 png_ptr->current_text[length] = '\0';
1174 png_ptr->current_text_ptr = png_ptr->current_text;
1175 png_ptr->current_text_size = (png_size_t)length;
1176 png_ptr->current_text_left = (png_size_t)length;
1177 png_ptr->process_mode = PNG_READ_zTXt_MODE;
1178}
1179
1180void /* PRIVATE */
1181png_push_read_zTXt(png_structp png_ptr, png_infop info_ptr)
1182{
1183 if (png_ptr->buffer_size && png_ptr->current_text_left)
1184 {
1185 png_size_t text_size;
1186
1187 if (png_ptr->buffer_size < (png_uint_32)png_ptr->current_text_left)
1188 text_size = png_ptr->buffer_size;
1189 else
1190 text_size = png_ptr->current_text_left;
1191 png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
1192 png_ptr->current_text_left -= text_size;
1193 png_ptr->current_text_ptr += text_size;
1194 }
1195 if (!(png_ptr->current_text_left))
1196 {
1197 png_textp text_ptr;
1198 png_charp text;
1199 png_charp key;
1200 int ret;
1201 png_size_t text_size, key_size;
1202
1203 if (png_ptr->buffer_size < 4)
1204 {
1205 png_push_save_buffer(png_ptr);
1206 return;
1207 }
1208
1209 png_push_crc_finish(png_ptr);
1210
1211 key = png_ptr->current_text;
1212
1213 for (text = key; *text; text++)
1214 /* empty loop */ ;
1215
1216 /* zTXt can't have zero text */
1217 if (text == key + png_ptr->current_text_size)
1218 {
1219 png_ptr->current_text = NULL;
1220 png_free(png_ptr, key);
1221 return;
1222 }
1223
1224 text++;
1225
1226 if (*text != PNG_TEXT_COMPRESSION_zTXt) /* check compression byte */
1227 {
1228 png_ptr->current_text = NULL;
1229 png_free(png_ptr, key);
1230 return;
1231 }
1232
1233 text++;
1234
1235 png_ptr->zstream.next_in = (png_bytep )text;
1236 png_ptr->zstream.avail_in = (uInt)(png_ptr->current_text_size -
1237 (text - key));
1238 png_ptr->zstream.next_out = png_ptr->zbuf;
1239 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
1240
1241 key_size = text - key;
1242 text_size = 0;
1243 text = NULL;
1244 ret = Z_STREAM_END;
1245
1246 while (png_ptr->zstream.avail_in)
1247 {
1248 ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
1249 if (ret != Z_OK && ret != Z_STREAM_END)
1250 {
1251 inflateReset(&png_ptr->zstream);
1252 png_ptr->zstream.avail_in = 0;
1253 png_ptr->current_text = NULL;
1254 png_free(png_ptr, key);
1255 png_free(png_ptr, text);
1256 return;
1257 }
1258 if (!(png_ptr->zstream.avail_out) || ret == Z_STREAM_END)
1259 {
1260 if (text == NULL)
1261 {
1262 text = (png_charp)png_malloc(png_ptr,
1263 (png_uint_32)(png_ptr->zbuf_size - png_ptr->zstream.avail_out
1264 + key_size + 1));
1265 png_memcpy(text + key_size, png_ptr->zbuf,
1266 png_ptr->zbuf_size - png_ptr->zstream.avail_out);
1267 png_memcpy(text, key, key_size);
1268 text_size = key_size + png_ptr->zbuf_size -
1269 png_ptr->zstream.avail_out;
1270 *(text + text_size) = '\0';
1271 }
1272 else
1273 {
1274 png_charp tmp;
1275
1276 tmp = text;
1277 text = (png_charp)png_malloc(png_ptr, text_size +
1278 (png_uint_32)(png_ptr->zbuf_size - png_ptr->zstream.avail_out
1279 + 1));
1280 png_memcpy(text, tmp, text_size);
1281 png_free(png_ptr, tmp);
1282 png_memcpy(text + text_size, png_ptr->zbuf,
1283 png_ptr->zbuf_size - png_ptr->zstream.avail_out);
1284 text_size += png_ptr->zbuf_size - png_ptr->zstream.avail_out;
1285 *(text + text_size) = '\0';
1286 }
1287 if (ret != Z_STREAM_END)
1288 {
1289 png_ptr->zstream.next_out = png_ptr->zbuf;
1290 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
1291 }
1292 }
1293 else
1294 {
1295 break;
1296 }
1297
1298 if (ret == Z_STREAM_END)
1299 break;
1300 }
1301
1302 inflateReset(&png_ptr->zstream);
1303 png_ptr->zstream.avail_in = 0;
1304
1305 if (ret != Z_STREAM_END)
1306 {
1307 png_ptr->current_text = NULL;
1308 png_free(png_ptr, key);
1309 png_free(png_ptr, text);
1310 return;
1311 }
1312
1313 png_ptr->current_text = NULL;
1314 png_free(png_ptr, key);
1315 key = text;
1316 text += key_size;
1317
1318 text_ptr = (png_textp)png_malloc(png_ptr,
1319 (png_uint_32)png_sizeof(png_text));
1320 text_ptr->compression = PNG_TEXT_COMPRESSION_zTXt;
1321 text_ptr->key = key;
1322#ifdef PNG_iTXt_SUPPORTED
1323 text_ptr->lang = NULL;
1324 text_ptr->lang_key = NULL;
1325#endif
1326 text_ptr->text = text;
1327
1328 ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
1329
1330 png_free(png_ptr, key);
1331 png_free(png_ptr, text_ptr);
1332
1333 if (ret)
1334 png_warning(png_ptr, "Insufficient memory to store text chunk.");
1335 }
1336}
1337#endif
1338
1339#if defined(PNG_READ_iTXt_SUPPORTED)
1340void /* PRIVATE */
1341png_push_handle_iTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
1342 length)
1343{
1344 if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
1345 {
1346 png_error(png_ptr, "Out of place iTXt");
1347 /* to quiet some compiler warnings */
1348 if(info_ptr == NULL) return;
1349 }
1350
1351#ifdef PNG_MAX_MALLOC_64K
1352 png_ptr->skip_length = 0; /* This may not be necessary */
1353
1354 if (length > (png_uint_32)65535L) /* Can't hold entire string in memory */
1355 {
1356 png_warning(png_ptr, "iTXt chunk too large to fit in memory");
1357 png_ptr->skip_length = length - (png_uint_32)65535L;
1358 length = (png_uint_32)65535L;
1359 }
1360#endif
1361
1362 png_ptr->current_text = (png_charp)png_malloc(png_ptr,
1363 (png_uint_32)(length+1));
1364 png_ptr->current_text[length] = '\0';
1365 png_ptr->current_text_ptr = png_ptr->current_text;
1366 png_ptr->current_text_size = (png_size_t)length;
1367 png_ptr->current_text_left = (png_size_t)length;
1368 png_ptr->process_mode = PNG_READ_iTXt_MODE;
1369}
1370
1371void /* PRIVATE */
1372png_push_read_iTXt(png_structp png_ptr, png_infop info_ptr)
1373{
1374
1375 if (png_ptr->buffer_size && png_ptr->current_text_left)
1376 {
1377 png_size_t text_size;
1378
1379 if (png_ptr->buffer_size < png_ptr->current_text_left)
1380 text_size = png_ptr->buffer_size;
1381 else
1382 text_size = png_ptr->current_text_left;
1383 png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
1384 png_ptr->current_text_left -= text_size;
1385 png_ptr->current_text_ptr += text_size;
1386 }
1387 if (!(png_ptr->current_text_left))
1388 {
1389 png_textp text_ptr;
1390 png_charp key;
1391 int comp_flag;
1392 png_charp lang;
1393 png_charp lang_key;
1394 png_charp text;
1395 int ret;
1396
1397 if (png_ptr->buffer_size < 4)
1398 {
1399 png_push_save_buffer(png_ptr);
1400 return;
1401 }
1402
1403 png_push_crc_finish(png_ptr);
1404
1405#if defined(PNG_MAX_MALLOC_64K)
1406 if (png_ptr->skip_length)
1407 return;
1408#endif
1409
1410 key = png_ptr->current_text;
1411
1412 for (lang = key; *lang; lang++)
1413 /* empty loop */ ;
1414
1415 if (lang != key + png_ptr->current_text_size)
1416 lang++;
1417
1418 comp_flag = *lang++;
1419 lang++; /* skip comp_type, always zero */
1420
1421 for (lang_key = lang; *lang_key; lang_key++)
1422 /* empty loop */ ;
1423 lang_key++; /* skip NUL separator */
1424
1425 for (text = lang_key; *text; text++)
1426 /* empty loop */ ;
1427
1428 if (text != key + png_ptr->current_text_size)
1429 text++;
1430
1431 text_ptr = (png_textp)png_malloc(png_ptr,
1432 (png_uint_32)png_sizeof(png_text));
1433 text_ptr->compression = comp_flag + 2;
1434 text_ptr->key = key;
1435 text_ptr->lang = lang;
1436 text_ptr->lang_key = lang_key;
1437 text_ptr->text = text;
1438 text_ptr->text_length = 0;
1439 text_ptr->itxt_length = png_strlen(text);
1440
1441 ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
1442
1443 png_ptr->current_text = NULL;
1444
1445 png_free(png_ptr, text_ptr);
1446 if (ret)
1447 png_warning(png_ptr, "Insufficient memory to store iTXt chunk.");
1448 }
1449}
1450#endif
1451
1452/* This function is called when we haven't found a handler for this
1453 * chunk. If there isn't a problem with the chunk itself (ie a bad chunk
1454 * name or a critical chunk), the chunk is (currently) silently ignored.
1455 */
1456void /* PRIVATE */
1457png_push_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32
1458 length)
1459{
1460 png_uint_32 skip=0;
1461 png_check_chunk_name(png_ptr, png_ptr->chunk_name);
1462
1463 if (!(png_ptr->chunk_name[0] & 0x20))
1464 {
1465#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
1466 if(png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
1467 PNG_HANDLE_CHUNK_ALWAYS
1468#if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
1469 && png_ptr->read_user_chunk_fn == NULL
1470#endif
1471 )
1472#endif
1473 png_chunk_error(png_ptr, "unknown critical chunk");
1474
1475 /* to quiet compiler warnings about unused info_ptr */
1476 if (info_ptr == NULL)
1477 return;
1478 }
1479
1480#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
1481 if (png_ptr->flags & PNG_FLAG_KEEP_UNKNOWN_CHUNKS)
1482 {
1483 png_unknown_chunk chunk;
1484
1485#ifdef PNG_MAX_MALLOC_64K
1486 if (length > (png_uint_32)65535L)
1487 {
1488 png_warning(png_ptr, "unknown chunk too large to fit in memory");
1489 skip = length - (png_uint_32)65535L;
1490 length = (png_uint_32)65535L;
1491 }
1492#endif
1493
1494 png_strcpy((png_charp)chunk.name, (png_charp)png_ptr->chunk_name);
1495 chunk.data = (png_bytep)png_malloc(png_ptr, length);
1496 png_crc_read(png_ptr, chunk.data, length);
1497 chunk.size = length;
1498#if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
1499 if(png_ptr->read_user_chunk_fn != NULL)
1500 {
1501 /* callback to user unknown chunk handler */
1502 if ((*(png_ptr->read_user_chunk_fn)) (png_ptr, &chunk) <= 0)
1503 {
1504 if (!(png_ptr->chunk_name[0] & 0x20))
1505 if(png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
1506 PNG_HANDLE_CHUNK_ALWAYS)
1507 png_chunk_error(png_ptr, "unknown critical chunk");
1508 }
1509 png_set_unknown_chunks(png_ptr, info_ptr, &chunk, 1);
1510 }
1511 else
1512#endif
1513 png_set_unknown_chunks(png_ptr, info_ptr, &chunk, 1);
1514 png_free(png_ptr, chunk.data);
1515 }
1516 else
1517#endif
1518 skip=length;
1519 png_push_crc_skip(png_ptr, skip);
1520}
1521
1522void /* PRIVATE */
1523png_push_have_info(png_structp png_ptr, png_infop info_ptr)
1524{
1525 if (png_ptr->info_fn != NULL)
1526 (*(png_ptr->info_fn))(png_ptr, info_ptr);
1527}
1528
1529void /* PRIVATE */
1530png_push_have_end(png_structp png_ptr, png_infop info_ptr)
1531{
1532 if (png_ptr->end_fn != NULL)
1533 (*(png_ptr->end_fn))(png_ptr, info_ptr);
1534}
1535
1536void /* PRIVATE */
1537png_push_have_row(png_structp png_ptr, png_bytep row)
1538{
1539 if (png_ptr->row_fn != NULL)
1540 (*(png_ptr->row_fn))(png_ptr, row, png_ptr->row_number,
1541 (int)png_ptr->pass);
1542}
1543
1544void PNGAPI
1545png_progressive_combine_row (png_structp png_ptr,
1546 png_bytep old_row, png_bytep new_row)
1547{
1548#ifdef PNG_USE_LOCAL_ARRAYS
1549 const int FARDATA png_pass_dsp_mask[7] =
1550 {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
1551#endif
1552 if (new_row != NULL) /* new_row must == png_ptr->row_buf here. */
1553 png_combine_row(png_ptr, old_row, png_pass_dsp_mask[png_ptr->pass]);
1554}
1555
1556void PNGAPI
1557png_set_progressive_read_fn(png_structp png_ptr, png_voidp progressive_ptr,
1558 png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,
1559 png_progressive_end_ptr end_fn)
1560{
1561 png_ptr->info_fn = info_fn;
1562 png_ptr->row_fn = row_fn;
1563 png_ptr->end_fn = end_fn;
1564
1565 png_set_read_fn(png_ptr, progressive_ptr, png_push_fill_buffer);
1566}
1567
1568png_voidp PNGAPI
1569png_get_progressive_ptr(png_structp png_ptr)
1570{
1571 return png_ptr->io_ptr;
1572}
1573#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
wxWidgets (Impactor)