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view libs/libpng/pngpread.c @ 35:643f4ab609a4
added readme and license
| author | John Tsiombikas <nuclear@member.fsf.org> |
|---|---|
| date | Sat, 31 Oct 2015 05:45:35 +0200 |
| parents | |
| children |
line source
2 /* pngpread.c - read a png file in push mode
3 *
4 * Last changed in libpng 1.2.32 [September 18, 2008]
5 * For conditions of distribution and use, see copyright notice in png.h
6 * Copyright (c) 1998-2008 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 */
11 #define PNG_INTERNAL
12 #include "png.h"
13 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
15 /* push model modes */
16 #define PNG_READ_SIG_MODE 0
17 #define PNG_READ_CHUNK_MODE 1
18 #define PNG_READ_IDAT_MODE 2
19 #define PNG_SKIP_MODE 3
20 #define PNG_READ_tEXt_MODE 4
21 #define PNG_READ_zTXt_MODE 5
22 #define PNG_READ_DONE_MODE 6
23 #define PNG_READ_iTXt_MODE 7
24 #define PNG_ERROR_MODE 8
26 void PNGAPI
27 png_process_data(png_structp png_ptr, png_infop info_ptr,
28 png_bytep buffer, png_size_t buffer_size)
29 {
30 if (png_ptr == NULL || info_ptr == NULL) return;
31 png_push_restore_buffer(png_ptr, buffer, buffer_size);
33 while (png_ptr->buffer_size)
34 {
35 png_process_some_data(png_ptr, info_ptr);
36 }
37 }
39 /* What we do with the incoming data depends on what we were previously
40 * doing before we ran out of data...
41 */
42 void /* PRIVATE */
43 png_process_some_data(png_structp png_ptr, png_infop info_ptr)
44 {
45 if (png_ptr == NULL) return;
46 switch (png_ptr->process_mode)
47 {
48 case PNG_READ_SIG_MODE:
49 {
50 png_push_read_sig(png_ptr, info_ptr);
51 break;
52 }
53 case PNG_READ_CHUNK_MODE:
54 {
55 png_push_read_chunk(png_ptr, info_ptr);
56 break;
57 }
58 case PNG_READ_IDAT_MODE:
59 {
60 png_push_read_IDAT(png_ptr);
61 break;
62 }
63 #if defined(PNG_READ_tEXt_SUPPORTED)
64 case PNG_READ_tEXt_MODE:
65 {
66 png_push_read_tEXt(png_ptr, info_ptr);
67 break;
68 }
69 #endif
70 #if defined(PNG_READ_zTXt_SUPPORTED)
71 case PNG_READ_zTXt_MODE:
72 {
73 png_push_read_zTXt(png_ptr, info_ptr);
74 break;
75 }
76 #endif
77 #if defined(PNG_READ_iTXt_SUPPORTED)
78 case PNG_READ_iTXt_MODE:
79 {
80 png_push_read_iTXt(png_ptr, info_ptr);
81 break;
82 }
83 #endif
84 case PNG_SKIP_MODE:
85 {
86 png_push_crc_finish(png_ptr);
87 break;
88 }
89 default:
90 {
91 png_ptr->buffer_size = 0;
92 break;
93 }
94 }
95 }
97 /* Read any remaining signature bytes from the stream and compare them with
98 * the correct PNG signature. It is possible that this routine is called
99 * with bytes already read from the signature, either because they have been
100 * checked by the calling application, or because of multiple calls to this
101 * routine.
102 */
103 void /* PRIVATE */
104 png_push_read_sig(png_structp png_ptr, png_infop info_ptr)
105 {
106 png_size_t num_checked = png_ptr->sig_bytes,
107 num_to_check = 8 - num_checked;
109 if (png_ptr->buffer_size < num_to_check)
110 {
111 num_to_check = png_ptr->buffer_size;
112 }
114 png_push_fill_buffer(png_ptr, &(info_ptr->signature[num_checked]),
115 num_to_check);
116 png_ptr->sig_bytes = (png_byte)(png_ptr->sig_bytes + num_to_check);
118 if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
119 {
120 if (num_checked < 4 &&
121 png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
122 png_error(png_ptr, "Not a PNG file");
123 else
124 png_error(png_ptr, "PNG file corrupted by ASCII conversion");
125 }
126 else
127 {
128 if (png_ptr->sig_bytes >= 8)
129 {
130 png_ptr->process_mode = PNG_READ_CHUNK_MODE;
131 }
132 }
133 }
135 void /* PRIVATE */
136 png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
137 {
138 #ifdef PNG_USE_LOCAL_ARRAYS
139 PNG_CONST PNG_IHDR;
140 PNG_CONST PNG_IDAT;
141 PNG_CONST PNG_IEND;
142 PNG_CONST PNG_PLTE;
143 #if defined(PNG_READ_bKGD_SUPPORTED)
144 PNG_CONST PNG_bKGD;
145 #endif
146 #if defined(PNG_READ_cHRM_SUPPORTED)
147 PNG_CONST PNG_cHRM;
148 #endif
149 #if defined(PNG_READ_gAMA_SUPPORTED)
150 PNG_CONST PNG_gAMA;
151 #endif
152 #if defined(PNG_READ_hIST_SUPPORTED)
153 PNG_CONST PNG_hIST;
154 #endif
155 #if defined(PNG_READ_iCCP_SUPPORTED)
156 PNG_CONST PNG_iCCP;
157 #endif
158 #if defined(PNG_READ_iTXt_SUPPORTED)
159 PNG_CONST PNG_iTXt;
160 #endif
161 #if defined(PNG_READ_oFFs_SUPPORTED)
162 PNG_CONST PNG_oFFs;
163 #endif
164 #if defined(PNG_READ_pCAL_SUPPORTED)
165 PNG_CONST PNG_pCAL;
166 #endif
167 #if defined(PNG_READ_pHYs_SUPPORTED)
168 PNG_CONST PNG_pHYs;
169 #endif
170 #if defined(PNG_READ_sBIT_SUPPORTED)
171 PNG_CONST PNG_sBIT;
172 #endif
173 #if defined(PNG_READ_sCAL_SUPPORTED)
174 PNG_CONST PNG_sCAL;
175 #endif
176 #if defined(PNG_READ_sRGB_SUPPORTED)
177 PNG_CONST PNG_sRGB;
178 #endif
179 #if defined(PNG_READ_sPLT_SUPPORTED)
180 PNG_CONST PNG_sPLT;
181 #endif
182 #if defined(PNG_READ_tEXt_SUPPORTED)
183 PNG_CONST PNG_tEXt;
184 #endif
185 #if defined(PNG_READ_tIME_SUPPORTED)
186 PNG_CONST PNG_tIME;
187 #endif
188 #if defined(PNG_READ_tRNS_SUPPORTED)
189 PNG_CONST PNG_tRNS;
190 #endif
191 #if defined(PNG_READ_zTXt_SUPPORTED)
192 PNG_CONST PNG_zTXt;
193 #endif
194 #endif /* PNG_USE_LOCAL_ARRAYS */
195 /* First we make sure we have enough data for the 4 byte chunk name
196 * and the 4 byte chunk length before proceeding with decoding the
197 * chunk data. To fully decode each of these chunks, we also make
198 * sure we have enough data in the buffer for the 4 byte CRC at the
199 * end of every chunk (except IDAT, which is handled separately).
200 */
201 if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
202 {
203 png_byte chunk_length[4];
205 if (png_ptr->buffer_size < 8)
206 {
207 png_push_save_buffer(png_ptr);
208 return;
209 }
211 png_push_fill_buffer(png_ptr, chunk_length, 4);
212 png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
213 png_reset_crc(png_ptr);
214 png_crc_read(png_ptr, png_ptr->chunk_name, 4);
215 png_check_chunk_name(png_ptr, png_ptr->chunk_name);
216 png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
217 }
219 if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
220 if (png_ptr->mode & PNG_AFTER_IDAT)
221 png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
223 if (!png_memcmp(png_ptr->chunk_name, png_IHDR, 4))
224 {
225 if (png_ptr->push_length != 13)
226 png_error(png_ptr, "Invalid IHDR length");
227 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
228 {
229 png_push_save_buffer(png_ptr);
230 return;
231 }
232 png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length);
233 }
234 else if (!png_memcmp(png_ptr->chunk_name, png_IEND, 4))
235 {
236 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
237 {
238 png_push_save_buffer(png_ptr);
239 return;
240 }
241 png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length);
243 png_ptr->process_mode = PNG_READ_DONE_MODE;
244 png_push_have_end(png_ptr, info_ptr);
245 }
246 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
247 else if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name))
248 {
249 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
250 {
251 png_push_save_buffer(png_ptr);
252 return;
253 }
254 if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
255 png_ptr->mode |= PNG_HAVE_IDAT;
256 png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length);
257 if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
258 png_ptr->mode |= PNG_HAVE_PLTE;
259 else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
260 {
261 if (!(png_ptr->mode & PNG_HAVE_IHDR))
262 png_error(png_ptr, "Missing IHDR before IDAT");
263 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
264 !(png_ptr->mode & PNG_HAVE_PLTE))
265 png_error(png_ptr, "Missing PLTE before IDAT");
266 }
267 }
268 #endif
269 else if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
270 {
271 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
272 {
273 png_push_save_buffer(png_ptr);
274 return;
275 }
276 png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
277 }
278 else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
279 {
280 /* If we reach an IDAT chunk, this means we have read all of the
281 * header chunks, and we can start reading the image (or if this
282 * is called after the image has been read - we have an error).
283 */
284 if (!(png_ptr->mode & PNG_HAVE_IHDR))
285 png_error(png_ptr, "Missing IHDR before IDAT");
286 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
287 !(png_ptr->mode & PNG_HAVE_PLTE))
288 png_error(png_ptr, "Missing PLTE before IDAT");
290 if (png_ptr->mode & PNG_HAVE_IDAT)
291 {
292 if (!(png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
293 if (png_ptr->push_length == 0)
294 return;
296 if (png_ptr->mode & PNG_AFTER_IDAT)
297 png_error(png_ptr, "Too many IDAT's found");
298 }
300 png_ptr->idat_size = png_ptr->push_length;
301 png_ptr->mode |= PNG_HAVE_IDAT;
302 png_ptr->process_mode = PNG_READ_IDAT_MODE;
303 png_push_have_info(png_ptr, info_ptr);
304 png_ptr->zstream.avail_out = (uInt)png_ptr->irowbytes;
305 png_ptr->zstream.next_out = png_ptr->row_buf;
306 return;
307 }
308 #if defined(PNG_READ_gAMA_SUPPORTED)
309 else if (!png_memcmp(png_ptr->chunk_name, png_gAMA, 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 png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length);
317 }
318 #endif
319 #if defined(PNG_READ_sBIT_SUPPORTED)
320 else if (!png_memcmp(png_ptr->chunk_name, png_sBIT, 4))
321 {
322 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
323 {
324 png_push_save_buffer(png_ptr);
325 return;
326 }
327 png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length);
328 }
329 #endif
330 #if defined(PNG_READ_cHRM_SUPPORTED)
331 else if (!png_memcmp(png_ptr->chunk_name, png_cHRM, 4))
332 {
333 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
334 {
335 png_push_save_buffer(png_ptr);
336 return;
337 }
338 png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length);
339 }
340 #endif
341 #if defined(PNG_READ_sRGB_SUPPORTED)
342 else if (!png_memcmp(png_ptr->chunk_name, png_sRGB, 4))
343 {
344 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
345 {
346 png_push_save_buffer(png_ptr);
347 return;
348 }
349 png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length);
350 }
351 #endif
352 #if defined(PNG_READ_iCCP_SUPPORTED)
353 else if (!png_memcmp(png_ptr->chunk_name, png_iCCP, 4))
354 {
355 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
356 {
357 png_push_save_buffer(png_ptr);
358 return;
359 }
360 png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length);
361 }
362 #endif
363 #if defined(PNG_READ_sPLT_SUPPORTED)
364 else if (!png_memcmp(png_ptr->chunk_name, png_sPLT, 4))
365 {
366 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
367 {
368 png_push_save_buffer(png_ptr);
369 return;
370 }
371 png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length);
372 }
373 #endif
374 #if defined(PNG_READ_tRNS_SUPPORTED)
375 else if (!png_memcmp(png_ptr->chunk_name, png_tRNS, 4))
376 {
377 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
378 {
379 png_push_save_buffer(png_ptr);
380 return;
381 }
382 png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length);
383 }
384 #endif
385 #if defined(PNG_READ_bKGD_SUPPORTED)
386 else if (!png_memcmp(png_ptr->chunk_name, png_bKGD, 4))
387 {
388 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
389 {
390 png_push_save_buffer(png_ptr);
391 return;
392 }
393 png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length);
394 }
395 #endif
396 #if defined(PNG_READ_hIST_SUPPORTED)
397 else if (!png_memcmp(png_ptr->chunk_name, png_hIST, 4))
398 {
399 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
400 {
401 png_push_save_buffer(png_ptr);
402 return;
403 }
404 png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length);
405 }
406 #endif
407 #if defined(PNG_READ_pHYs_SUPPORTED)
408 else if (!png_memcmp(png_ptr->chunk_name, png_pHYs, 4))
409 {
410 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
411 {
412 png_push_save_buffer(png_ptr);
413 return;
414 }
415 png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length);
416 }
417 #endif
418 #if defined(PNG_READ_oFFs_SUPPORTED)
419 else if (!png_memcmp(png_ptr->chunk_name, png_oFFs, 4))
420 {
421 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
422 {
423 png_push_save_buffer(png_ptr);
424 return;
425 }
426 png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length);
427 }
428 #endif
429 #if defined(PNG_READ_pCAL_SUPPORTED)
430 else if (!png_memcmp(png_ptr->chunk_name, png_pCAL, 4))
431 {
432 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
433 {
434 png_push_save_buffer(png_ptr);
435 return;
436 }
437 png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length);
438 }
439 #endif
440 #if defined(PNG_READ_sCAL_SUPPORTED)
441 else if (!png_memcmp(png_ptr->chunk_name, png_sCAL, 4))
442 {
443 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
444 {
445 png_push_save_buffer(png_ptr);
446 return;
447 }
448 png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length);
449 }
450 #endif
451 #if defined(PNG_READ_tIME_SUPPORTED)
452 else if (!png_memcmp(png_ptr->chunk_name, png_tIME, 4))
453 {
454 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
455 {
456 png_push_save_buffer(png_ptr);
457 return;
458 }
459 png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length);
460 }
461 #endif
462 #if defined(PNG_READ_tEXt_SUPPORTED)
463 else if (!png_memcmp(png_ptr->chunk_name, png_tEXt, 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 png_push_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length);
471 }
472 #endif
473 #if defined(PNG_READ_zTXt_SUPPORTED)
474 else if (!png_memcmp(png_ptr->chunk_name, png_zTXt, 4))
475 {
476 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
477 {
478 png_push_save_buffer(png_ptr);
479 return;
480 }
481 png_push_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
482 }
483 #endif
484 #if defined(PNG_READ_iTXt_SUPPORTED)
485 else if (!png_memcmp(png_ptr->chunk_name, png_iTXt, 4))
486 {
487 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
488 {
489 png_push_save_buffer(png_ptr);
490 return;
491 }
492 png_push_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
493 }
494 #endif
495 else
496 {
497 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
498 {
499 png_push_save_buffer(png_ptr);
500 return;
501 }
502 png_push_handle_unknown(png_ptr, info_ptr, png_ptr->push_length);
503 }
505 png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
506 }
508 void /* PRIVATE */
509 png_push_crc_skip(png_structp png_ptr, png_uint_32 skip)
510 {
511 png_ptr->process_mode = PNG_SKIP_MODE;
512 png_ptr->skip_length = skip;
513 }
515 void /* PRIVATE */
516 png_push_crc_finish(png_structp png_ptr)
517 {
518 if (png_ptr->skip_length && png_ptr->save_buffer_size)
519 {
520 png_size_t save_size;
522 if (png_ptr->skip_length < (png_uint_32)png_ptr->save_buffer_size)
523 save_size = (png_size_t)png_ptr->skip_length;
524 else
525 save_size = png_ptr->save_buffer_size;
527 png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
529 png_ptr->skip_length -= save_size;
530 png_ptr->buffer_size -= save_size;
531 png_ptr->save_buffer_size -= save_size;
532 png_ptr->save_buffer_ptr += save_size;
533 }
534 if (png_ptr->skip_length && png_ptr->current_buffer_size)
535 {
536 png_size_t save_size;
538 if (png_ptr->skip_length < (png_uint_32)png_ptr->current_buffer_size)
539 save_size = (png_size_t)png_ptr->skip_length;
540 else
541 save_size = png_ptr->current_buffer_size;
543 png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
545 png_ptr->skip_length -= save_size;
546 png_ptr->buffer_size -= save_size;
547 png_ptr->current_buffer_size -= save_size;
548 png_ptr->current_buffer_ptr += save_size;
549 }
550 if (!png_ptr->skip_length)
551 {
552 if (png_ptr->buffer_size < 4)
553 {
554 png_push_save_buffer(png_ptr);
555 return;
556 }
558 png_crc_finish(png_ptr, 0);
559 png_ptr->process_mode = PNG_READ_CHUNK_MODE;
560 }
561 }
563 void PNGAPI
564 png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
565 {
566 png_bytep ptr;
568 if (png_ptr == NULL) return;
569 ptr = buffer;
570 if (png_ptr->save_buffer_size)
571 {
572 png_size_t save_size;
574 if (length < png_ptr->save_buffer_size)
575 save_size = length;
576 else
577 save_size = png_ptr->save_buffer_size;
579 png_memcpy(ptr, png_ptr->save_buffer_ptr, save_size);
580 length -= save_size;
581 ptr += save_size;
582 png_ptr->buffer_size -= save_size;
583 png_ptr->save_buffer_size -= save_size;
584 png_ptr->save_buffer_ptr += save_size;
585 }
586 if (length && png_ptr->current_buffer_size)
587 {
588 png_size_t save_size;
590 if (length < png_ptr->current_buffer_size)
591 save_size = length;
592 else
593 save_size = png_ptr->current_buffer_size;
595 png_memcpy(ptr, png_ptr->current_buffer_ptr, save_size);
596 png_ptr->buffer_size -= save_size;
597 png_ptr->current_buffer_size -= save_size;
598 png_ptr->current_buffer_ptr += save_size;
599 }
600 }
602 void /* PRIVATE */
603 png_push_save_buffer(png_structp png_ptr)
604 {
605 if (png_ptr->save_buffer_size)
606 {
607 if (png_ptr->save_buffer_ptr != png_ptr->save_buffer)
608 {
609 png_size_t i, istop;
610 png_bytep sp;
611 png_bytep dp;
613 istop = png_ptr->save_buffer_size;
614 for (i = 0, sp = png_ptr->save_buffer_ptr, dp = png_ptr->save_buffer;
615 i < istop; i++, sp++, dp++)
616 {
617 *dp = *sp;
618 }
619 }
620 }
621 if (png_ptr->save_buffer_size + png_ptr->current_buffer_size >
622 png_ptr->save_buffer_max)
623 {
624 png_size_t new_max;
625 png_bytep old_buffer;
627 if (png_ptr->save_buffer_size > PNG_SIZE_MAX -
628 (png_ptr->current_buffer_size + 256))
629 {
630 png_error(png_ptr, "Potential overflow of save_buffer");
631 }
632 new_max = png_ptr->save_buffer_size + png_ptr->current_buffer_size + 256;
633 old_buffer = png_ptr->save_buffer;
634 png_ptr->save_buffer = (png_bytep)png_malloc(png_ptr,
635 (png_uint_32)new_max);
636 png_memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size);
637 png_free(png_ptr, old_buffer);
638 png_ptr->save_buffer_max = new_max;
639 }
640 if (png_ptr->current_buffer_size)
641 {
642 png_memcpy(png_ptr->save_buffer + png_ptr->save_buffer_size,
643 png_ptr->current_buffer_ptr, png_ptr->current_buffer_size);
644 png_ptr->save_buffer_size += png_ptr->current_buffer_size;
645 png_ptr->current_buffer_size = 0;
646 }
647 png_ptr->save_buffer_ptr = png_ptr->save_buffer;
648 png_ptr->buffer_size = 0;
649 }
651 void /* PRIVATE */
652 png_push_restore_buffer(png_structp png_ptr, png_bytep buffer,
653 png_size_t buffer_length)
654 {
655 png_ptr->current_buffer = buffer;
656 png_ptr->current_buffer_size = buffer_length;
657 png_ptr->buffer_size = buffer_length + png_ptr->save_buffer_size;
658 png_ptr->current_buffer_ptr = png_ptr->current_buffer;
659 }
661 void /* PRIVATE */
662 png_push_read_IDAT(png_structp png_ptr)
663 {
664 #ifdef PNG_USE_LOCAL_ARRAYS
665 PNG_CONST PNG_IDAT;
666 #endif
667 if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
668 {
669 png_byte chunk_length[4];
671 if (png_ptr->buffer_size < 8)
672 {
673 png_push_save_buffer(png_ptr);
674 return;
675 }
677 png_push_fill_buffer(png_ptr, chunk_length, 4);
678 png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
679 png_reset_crc(png_ptr);
680 png_crc_read(png_ptr, png_ptr->chunk_name, 4);
681 png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
683 if (png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
684 {
685 png_ptr->process_mode = PNG_READ_CHUNK_MODE;
686 if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
687 png_error(png_ptr, "Not enough compressed data");
688 return;
689 }
691 png_ptr->idat_size = png_ptr->push_length;
692 }
693 if (png_ptr->idat_size && png_ptr->save_buffer_size)
694 {
695 png_size_t save_size;
697 if (png_ptr->idat_size < (png_uint_32)png_ptr->save_buffer_size)
698 {
699 save_size = (png_size_t)png_ptr->idat_size;
700 /* check for overflow */
701 if ((png_uint_32)save_size != png_ptr->idat_size)
702 png_error(png_ptr, "save_size overflowed in pngpread");
703 }
704 else
705 save_size = png_ptr->save_buffer_size;
707 png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
708 if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
709 png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size);
710 png_ptr->idat_size -= save_size;
711 png_ptr->buffer_size -= save_size;
712 png_ptr->save_buffer_size -= save_size;
713 png_ptr->save_buffer_ptr += save_size;
714 }
715 if (png_ptr->idat_size && png_ptr->current_buffer_size)
716 {
717 png_size_t save_size;
719 if (png_ptr->idat_size < (png_uint_32)png_ptr->current_buffer_size)
720 {
721 save_size = (png_size_t)png_ptr->idat_size;
722 /* check for overflow */
723 if ((png_uint_32)save_size != png_ptr->idat_size)
724 png_error(png_ptr, "save_size overflowed in pngpread");
725 }
726 else
727 save_size = png_ptr->current_buffer_size;
729 png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
730 if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
731 png_process_IDAT_data(png_ptr, png_ptr->current_buffer_ptr, save_size);
733 png_ptr->idat_size -= save_size;
734 png_ptr->buffer_size -= save_size;
735 png_ptr->current_buffer_size -= save_size;
736 png_ptr->current_buffer_ptr += save_size;
737 }
738 if (!png_ptr->idat_size)
739 {
740 if (png_ptr->buffer_size < 4)
741 {
742 png_push_save_buffer(png_ptr);
743 return;
744 }
746 png_crc_finish(png_ptr, 0);
747 png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
748 png_ptr->mode |= PNG_AFTER_IDAT;
749 }
750 }
752 void /* PRIVATE */
753 png_process_IDAT_data(png_structp png_ptr, png_bytep buffer,
754 png_size_t buffer_length)
755 {
756 int ret;
758 if ((png_ptr->flags & PNG_FLAG_ZLIB_FINISHED) && buffer_length)
759 png_error(png_ptr, "Extra compression data");
761 png_ptr->zstream.next_in = buffer;
762 png_ptr->zstream.avail_in = (uInt)buffer_length;
763 for (;;)
764 {
765 ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
766 if (ret != Z_OK)
767 {
768 if (ret == Z_STREAM_END)
769 {
770 if (png_ptr->zstream.avail_in)
771 png_error(png_ptr, "Extra compressed data");
772 if (!(png_ptr->zstream.avail_out))
773 {
774 png_push_process_row(png_ptr);
775 }
777 png_ptr->mode |= PNG_AFTER_IDAT;
778 png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
779 break;
780 }
781 else if (ret == Z_BUF_ERROR)
782 break;
783 else
784 png_error(png_ptr, "Decompression Error");
785 }
786 if (!(png_ptr->zstream.avail_out))
787 {
788 if ((
789 #if defined(PNG_READ_INTERLACING_SUPPORTED)
790 png_ptr->interlaced && png_ptr->pass > 6) ||
791 (!png_ptr->interlaced &&
792 #endif
793 png_ptr->row_number == png_ptr->num_rows))
794 {
795 if (png_ptr->zstream.avail_in)
796 png_warning(png_ptr, "Too much data in IDAT chunks");
797 png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
798 break;
799 }
800 png_push_process_row(png_ptr);
801 png_ptr->zstream.avail_out = (uInt)png_ptr->irowbytes;
802 png_ptr->zstream.next_out = png_ptr->row_buf;
803 }
804 else
805 break;
806 }
807 }
809 void /* PRIVATE */
810 png_push_process_row(png_structp png_ptr)
811 {
812 png_ptr->row_info.color_type = png_ptr->color_type;
813 png_ptr->row_info.width = png_ptr->iwidth;
814 png_ptr->row_info.channels = png_ptr->channels;
815 png_ptr->row_info.bit_depth = png_ptr->bit_depth;
816 png_ptr->row_info.pixel_depth = png_ptr->pixel_depth;
818 png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth,
819 png_ptr->row_info.width);
821 png_read_filter_row(png_ptr, &(png_ptr->row_info),
822 png_ptr->row_buf + 1, png_ptr->prev_row + 1,
823 (int)(png_ptr->row_buf[0]));
825 png_memcpy_check(png_ptr, png_ptr->prev_row, png_ptr->row_buf,
826 png_ptr->rowbytes + 1);
828 if (png_ptr->transformations || (png_ptr->flags&PNG_FLAG_STRIP_ALPHA))
829 png_do_read_transformations(png_ptr);
831 #if defined(PNG_READ_INTERLACING_SUPPORTED)
832 /* blow up interlaced rows to full size */
833 if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
834 {
835 if (png_ptr->pass < 6)
836 /* old interface (pre-1.0.9):
837 png_do_read_interlace(&(png_ptr->row_info),
838 png_ptr->row_buf + 1, png_ptr->pass, png_ptr->transformations);
839 */
840 png_do_read_interlace(png_ptr);
842 switch (png_ptr->pass)
843 {
844 case 0:
845 {
846 int i;
847 for (i = 0; i < 8 && png_ptr->pass == 0; i++)
848 {
849 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
850 png_read_push_finish_row(png_ptr); /* updates png_ptr->pass */
851 }
852 if (png_ptr->pass == 2) /* pass 1 might be empty */
853 {
854 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
855 {
856 png_push_have_row(png_ptr, png_bytep_NULL);
857 png_read_push_finish_row(png_ptr);
858 }
859 }
860 if (png_ptr->pass == 4 && png_ptr->height <= 4)
861 {
862 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
863 {
864 png_push_have_row(png_ptr, png_bytep_NULL);
865 png_read_push_finish_row(png_ptr);
866 }
867 }
868 if (png_ptr->pass == 6 && png_ptr->height <= 4)
869 {
870 png_push_have_row(png_ptr, png_bytep_NULL);
871 png_read_push_finish_row(png_ptr);
872 }
873 break;
874 }
875 case 1:
876 {
877 int i;
878 for (i = 0; i < 8 && png_ptr->pass == 1; i++)
879 {
880 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
881 png_read_push_finish_row(png_ptr);
882 }
883 if (png_ptr->pass == 2) /* skip top 4 generated rows */
884 {
885 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
886 {
887 png_push_have_row(png_ptr, png_bytep_NULL);
888 png_read_push_finish_row(png_ptr);
889 }
890 }
891 break;
892 }
893 case 2:
894 {
895 int i;
896 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
897 {
898 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
899 png_read_push_finish_row(png_ptr);
900 }
901 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
902 {
903 png_push_have_row(png_ptr, png_bytep_NULL);
904 png_read_push_finish_row(png_ptr);
905 }
906 if (png_ptr->pass == 4) /* pass 3 might be empty */
907 {
908 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
909 {
910 png_push_have_row(png_ptr, png_bytep_NULL);
911 png_read_push_finish_row(png_ptr);
912 }
913 }
914 break;
915 }
916 case 3:
917 {
918 int i;
919 for (i = 0; i < 4 && png_ptr->pass == 3; i++)
920 {
921 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
922 png_read_push_finish_row(png_ptr);
923 }
924 if (png_ptr->pass == 4) /* skip top two generated rows */
925 {
926 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
927 {
928 png_push_have_row(png_ptr, png_bytep_NULL);
929 png_read_push_finish_row(png_ptr);
930 }
931 }
932 break;
933 }
934 case 4:
935 {
936 int i;
937 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
938 {
939 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
940 png_read_push_finish_row(png_ptr);
941 }
942 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
943 {
944 png_push_have_row(png_ptr, png_bytep_NULL);
945 png_read_push_finish_row(png_ptr);
946 }
947 if (png_ptr->pass == 6) /* pass 5 might be empty */
948 {
949 png_push_have_row(png_ptr, png_bytep_NULL);
950 png_read_push_finish_row(png_ptr);
951 }
952 break;
953 }
954 case 5:
955 {
956 int i;
957 for (i = 0; i < 2 && png_ptr->pass == 5; i++)
958 {
959 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
960 png_read_push_finish_row(png_ptr);
961 }
962 if (png_ptr->pass == 6) /* skip top generated row */
963 {
964 png_push_have_row(png_ptr, png_bytep_NULL);
965 png_read_push_finish_row(png_ptr);
966 }
967 break;
968 }
969 case 6:
970 {
971 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
972 png_read_push_finish_row(png_ptr);
973 if (png_ptr->pass != 6)
974 break;
975 png_push_have_row(png_ptr, png_bytep_NULL);
976 png_read_push_finish_row(png_ptr);
977 }
978 }
979 }
980 else
981 #endif
982 {
983 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
984 png_read_push_finish_row(png_ptr);
985 }
986 }
988 void /* PRIVATE */
989 png_read_push_finish_row(png_structp png_ptr)
990 {
991 #ifdef PNG_USE_LOCAL_ARRAYS
992 /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
994 /* start of interlace block */
995 PNG_CONST int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
997 /* offset to next interlace block */
998 PNG_CONST int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
1000 /* start of interlace block in the y direction */
1001 PNG_CONST int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
1003 /* offset to next interlace block in the y direction */
1004 PNG_CONST int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
1006 /* Height of interlace block. This is not currently used - if you need
1007 * it, uncomment it here and in png.h
1008 PNG_CONST int FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
1009 */
1010 #endif
1012 png_ptr->row_number++;
1013 if (png_ptr->row_number < png_ptr->num_rows)
1014 return;
1016 if (png_ptr->interlaced)
1017 {
1018 png_ptr->row_number = 0;
1019 png_memset_check(png_ptr, png_ptr->prev_row, 0,
1020 png_ptr->rowbytes + 1);
1021 do
1022 {
1023 png_ptr->pass++;
1024 if ((png_ptr->pass == 1 && png_ptr->width < 5) ||
1025 (png_ptr->pass == 3 && png_ptr->width < 3) ||
1026 (png_ptr->pass == 5 && png_ptr->width < 2))
1027 png_ptr->pass++;
1029 if (png_ptr->pass > 7)
1030 png_ptr->pass--;
1031 if (png_ptr->pass >= 7)
1032 break;
1034 png_ptr->iwidth = (png_ptr->width +
1035 png_pass_inc[png_ptr->pass] - 1 -
1036 png_pass_start[png_ptr->pass]) /
1037 png_pass_inc[png_ptr->pass];
1039 png_ptr->irowbytes = PNG_ROWBYTES(png_ptr->pixel_depth,
1040 png_ptr->iwidth) + 1;
1042 if (png_ptr->transformations & PNG_INTERLACE)
1043 break;
1045 png_ptr->num_rows = (png_ptr->height +
1046 png_pass_yinc[png_ptr->pass] - 1 -
1047 png_pass_ystart[png_ptr->pass]) /
1048 png_pass_yinc[png_ptr->pass];
1050 } while (png_ptr->iwidth == 0 || png_ptr->num_rows == 0);
1051 }
1052 }
1054 #if defined(PNG_READ_tEXt_SUPPORTED)
1055 void /* PRIVATE */
1056 png_push_handle_tEXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
1057 length)
1058 {
1059 if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
1060 {
1061 png_error(png_ptr, "Out of place tEXt");
1062 info_ptr = info_ptr; /* to quiet some compiler warnings */
1063 }
1065 #ifdef PNG_MAX_MALLOC_64K
1066 png_ptr->skip_length = 0; /* This may not be necessary */
1068 if (length > (png_uint_32)65535L) /* Can't hold entire string in memory */
1069 {
1070 png_warning(png_ptr, "tEXt chunk too large to fit in memory");
1071 png_ptr->skip_length = length - (png_uint_32)65535L;
1072 length = (png_uint_32)65535L;
1073 }
1074 #endif
1076 png_ptr->current_text = (png_charp)png_malloc(png_ptr,
1077 (png_uint_32)(length + 1));
1078 png_ptr->current_text[length] = '\0';
1079 png_ptr->current_text_ptr = png_ptr->current_text;
1080 png_ptr->current_text_size = (png_size_t)length;
1081 png_ptr->current_text_left = (png_size_t)length;
1082 png_ptr->process_mode = PNG_READ_tEXt_MODE;
1083 }
1085 void /* PRIVATE */
1086 png_push_read_tEXt(png_structp png_ptr, png_infop info_ptr)
1087 {
1088 if (png_ptr->buffer_size && png_ptr->current_text_left)
1089 {
1090 png_size_t text_size;
1092 if (png_ptr->buffer_size < png_ptr->current_text_left)
1093 text_size = png_ptr->buffer_size;
1094 else
1095 text_size = png_ptr->current_text_left;
1096 png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
1097 png_ptr->current_text_left -= text_size;
1098 png_ptr->current_text_ptr += text_size;
1099 }
1100 if (!(png_ptr->current_text_left))
1101 {
1102 png_textp text_ptr;
1103 png_charp text;
1104 png_charp key;
1105 int ret;
1107 if (png_ptr->buffer_size < 4)
1108 {
1109 png_push_save_buffer(png_ptr);
1110 return;
1111 }
1113 png_push_crc_finish(png_ptr);
1115 #if defined(PNG_MAX_MALLOC_64K)
1116 if (png_ptr->skip_length)
1117 return;
1118 #endif
1120 key = png_ptr->current_text;
1122 for (text = key; *text; text++)
1123 /* empty loop */ ;
1125 if (text < key + png_ptr->current_text_size)
1126 text++;
1128 text_ptr = (png_textp)png_malloc(png_ptr,
1129 (png_uint_32)png_sizeof(png_text));
1130 text_ptr->compression = PNG_TEXT_COMPRESSION_NONE;
1131 text_ptr->key = key;
1132 #ifdef PNG_iTXt_SUPPORTED
1133 text_ptr->lang = NULL;
1134 text_ptr->lang_key = NULL;
1135 #endif
1136 text_ptr->text = text;
1138 ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
1140 png_free(png_ptr, key);
1141 png_free(png_ptr, text_ptr);
1142 png_ptr->current_text = NULL;
1144 if (ret)
1145 png_warning(png_ptr, "Insufficient memory to store text chunk.");
1146 }
1147 }
1148 #endif
1150 #if defined(PNG_READ_zTXt_SUPPORTED)
1151 void /* PRIVATE */
1152 png_push_handle_zTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
1153 length)
1154 {
1155 if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
1156 {
1157 png_error(png_ptr, "Out of place zTXt");
1158 info_ptr = info_ptr; /* to quiet some compiler warnings */
1159 }
1161 #ifdef PNG_MAX_MALLOC_64K
1162 /* We can't handle zTXt chunks > 64K, since we don't have enough space
1163 * to be able to store the uncompressed data. Actually, the threshold
1164 * is probably around 32K, but it isn't as definite as 64K is.
1165 */
1166 if (length > (png_uint_32)65535L)
1167 {
1168 png_warning(png_ptr, "zTXt chunk too large to fit in memory");
1169 png_push_crc_skip(png_ptr, length);
1170 return;
1171 }
1172 #endif
1174 png_ptr->current_text = (png_charp)png_malloc(png_ptr,
1175 (png_uint_32)(length + 1));
1176 png_ptr->current_text[length] = '\0';
1177 png_ptr->current_text_ptr = png_ptr->current_text;
1178 png_ptr->current_text_size = (png_size_t)length;
1179 png_ptr->current_text_left = (png_size_t)length;
1180 png_ptr->process_mode = PNG_READ_zTXt_MODE;
1181 }
1183 void /* PRIVATE */
1184 png_push_read_zTXt(png_structp png_ptr, png_infop info_ptr)
1185 {
1186 if (png_ptr->buffer_size && png_ptr->current_text_left)
1187 {
1188 png_size_t text_size;
1190 if (png_ptr->buffer_size < (png_uint_32)png_ptr->current_text_left)
1191 text_size = png_ptr->buffer_size;
1192 else
1193 text_size = png_ptr->current_text_left;
1194 png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
1195 png_ptr->current_text_left -= text_size;
1196 png_ptr->current_text_ptr += text_size;
1197 }
1198 if (!(png_ptr->current_text_left))
1199 {
1200 png_textp text_ptr;
1201 png_charp text;
1202 png_charp key;
1203 int ret;
1204 png_size_t text_size, key_size;
1206 if (png_ptr->buffer_size < 4)
1207 {
1208 png_push_save_buffer(png_ptr);
1209 return;
1210 }
1212 png_push_crc_finish(png_ptr);
1214 key = png_ptr->current_text;
1216 for (text = key; *text; text++)
1217 /* empty loop */ ;
1219 /* zTXt can't have zero text */
1220 if (text >= key + png_ptr->current_text_size)
1221 {
1222 png_ptr->current_text = NULL;
1223 png_free(png_ptr, key);
1224 return;
1225 }
1227 text++;
1229 if (*text != PNG_TEXT_COMPRESSION_zTXt) /* check compression byte */
1230 {
1231 png_ptr->current_text = NULL;
1232 png_free(png_ptr, key);
1233 return;
1234 }
1236 text++;
1238 png_ptr->zstream.next_in = (png_bytep )text;
1239 png_ptr->zstream.avail_in = (uInt)(png_ptr->current_text_size -
1240 (text - key));
1241 png_ptr->zstream.next_out = png_ptr->zbuf;
1242 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
1244 key_size = text - key;
1245 text_size = 0;
1246 text = NULL;
1247 ret = Z_STREAM_END;
1249 while (png_ptr->zstream.avail_in)
1250 {
1251 ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
1252 if (ret != Z_OK && ret != Z_STREAM_END)
1253 {
1254 inflateReset(&png_ptr->zstream);
1255 png_ptr->zstream.avail_in = 0;
1256 png_ptr->current_text = NULL;
1257 png_free(png_ptr, key);
1258 png_free(png_ptr, text);
1259 return;
1260 }
1261 if (!(png_ptr->zstream.avail_out) || ret == Z_STREAM_END)
1262 {
1263 if (text == NULL)
1264 {
1265 text = (png_charp)png_malloc(png_ptr,
1266 (png_uint_32)(png_ptr->zbuf_size
1267 - png_ptr->zstream.avail_out + key_size + 1));
1268 png_memcpy(text + key_size, png_ptr->zbuf,
1269 png_ptr->zbuf_size - png_ptr->zstream.avail_out);
1270 png_memcpy(text, key, key_size);
1271 text_size = key_size + png_ptr->zbuf_size -
1272 png_ptr->zstream.avail_out;
1273 *(text + text_size) = '\0';
1274 }
1275 else
1276 {
1277 png_charp tmp;
1279 tmp = text;
1280 text = (png_charp)png_malloc(png_ptr, text_size +
1281 (png_uint_32)(png_ptr->zbuf_size
1282 - png_ptr->zstream.avail_out + 1));
1283 png_memcpy(text, tmp, text_size);
1284 png_free(png_ptr, tmp);
1285 png_memcpy(text + text_size, png_ptr->zbuf,
1286 png_ptr->zbuf_size - png_ptr->zstream.avail_out);
1287 text_size += png_ptr->zbuf_size - png_ptr->zstream.avail_out;
1288 *(text + text_size) = '\0';
1289 }
1290 if (ret != Z_STREAM_END)
1291 {
1292 png_ptr->zstream.next_out = png_ptr->zbuf;
1293 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
1294 }
1295 }
1296 else
1297 {
1298 break;
1299 }
1301 if (ret == Z_STREAM_END)
1302 break;
1303 }
1305 inflateReset(&png_ptr->zstream);
1306 png_ptr->zstream.avail_in = 0;
1308 if (ret != Z_STREAM_END)
1309 {
1310 png_ptr->current_text = NULL;
1311 png_free(png_ptr, key);
1312 png_free(png_ptr, text);
1313 return;
1314 }
1316 png_ptr->current_text = NULL;
1317 png_free(png_ptr, key);
1318 key = text;
1319 text += key_size;
1321 text_ptr = (png_textp)png_malloc(png_ptr,
1322 (png_uint_32)png_sizeof(png_text));
1323 text_ptr->compression = PNG_TEXT_COMPRESSION_zTXt;
1324 text_ptr->key = key;
1325 #ifdef PNG_iTXt_SUPPORTED
1326 text_ptr->lang = NULL;
1327 text_ptr->lang_key = NULL;
1328 #endif
1329 text_ptr->text = text;
1331 ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
1333 png_free(png_ptr, key);
1334 png_free(png_ptr, text_ptr);
1336 if (ret)
1337 png_warning(png_ptr, "Insufficient memory to store text chunk.");
1338 }
1339 }
1340 #endif
1342 #if defined(PNG_READ_iTXt_SUPPORTED)
1343 void /* PRIVATE */
1344 png_push_handle_iTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
1345 length)
1346 {
1347 if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
1348 {
1349 png_error(png_ptr, "Out of place iTXt");
1350 info_ptr = info_ptr; /* to quiet some compiler warnings */
1351 }
1353 #ifdef PNG_MAX_MALLOC_64K
1354 png_ptr->skip_length = 0; /* This may not be necessary */
1356 if (length > (png_uint_32)65535L) /* Can't hold entire string in memory */
1357 {
1358 png_warning(png_ptr, "iTXt chunk too large to fit in memory");
1359 png_ptr->skip_length = length - (png_uint_32)65535L;
1360 length = (png_uint_32)65535L;
1361 }
1362 #endif
1364 png_ptr->current_text = (png_charp)png_malloc(png_ptr,
1365 (png_uint_32)(length + 1));
1366 png_ptr->current_text[length] = '\0';
1367 png_ptr->current_text_ptr = png_ptr->current_text;
1368 png_ptr->current_text_size = (png_size_t)length;
1369 png_ptr->current_text_left = (png_size_t)length;
1370 png_ptr->process_mode = PNG_READ_iTXt_MODE;
1371 }
1373 void /* PRIVATE */
1374 png_push_read_iTXt(png_structp png_ptr, png_infop info_ptr)
1375 {
1377 if (png_ptr->buffer_size && png_ptr->current_text_left)
1378 {
1379 png_size_t text_size;
1381 if (png_ptr->buffer_size < png_ptr->current_text_left)
1382 text_size = png_ptr->buffer_size;
1383 else
1384 text_size = png_ptr->current_text_left;
1385 png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
1386 png_ptr->current_text_left -= text_size;
1387 png_ptr->current_text_ptr += text_size;
1388 }
1389 if (!(png_ptr->current_text_left))
1390 {
1391 png_textp text_ptr;
1392 png_charp key;
1393 int comp_flag;
1394 png_charp lang;
1395 png_charp lang_key;
1396 png_charp text;
1397 int ret;
1399 if (png_ptr->buffer_size < 4)
1400 {
1401 png_push_save_buffer(png_ptr);
1402 return;
1403 }
1405 png_push_crc_finish(png_ptr);
1407 #if defined(PNG_MAX_MALLOC_64K)
1408 if (png_ptr->skip_length)
1409 return;
1410 #endif
1412 key = png_ptr->current_text;
1414 for (lang = key; *lang; lang++)
1415 /* empty loop */ ;
1417 if (lang < key + png_ptr->current_text_size - 3)
1418 lang++;
1420 comp_flag = *lang++;
1421 lang++; /* skip comp_type, always zero */
1423 for (lang_key = lang; *lang_key; lang_key++)
1424 /* empty loop */ ;
1425 lang_key++; /* skip NUL separator */
1427 text=lang_key;
1428 if (lang_key < key + png_ptr->current_text_size - 1)
1429 {
1430 for (; *text; text++)
1431 /* empty loop */ ;
1432 }
1434 if (text < key + png_ptr->current_text_size)
1435 text++;
1437 text_ptr = (png_textp)png_malloc(png_ptr,
1438 (png_uint_32)png_sizeof(png_text));
1439 text_ptr->compression = comp_flag + 2;
1440 text_ptr->key = key;
1441 text_ptr->lang = lang;
1442 text_ptr->lang_key = lang_key;
1443 text_ptr->text = text;
1444 text_ptr->text_length = 0;
1445 text_ptr->itxt_length = png_strlen(text);
1447 ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
1449 png_ptr->current_text = NULL;
1451 png_free(png_ptr, text_ptr);
1452 if (ret)
1453 png_warning(png_ptr, "Insufficient memory to store iTXt chunk.");
1454 }
1455 }
1456 #endif
1458 /* This function is called when we haven't found a handler for this
1459 * chunk. If there isn't a problem with the chunk itself (ie a bad chunk
1460 * name or a critical chunk), the chunk is (currently) silently ignored.
1461 */
1462 void /* PRIVATE */
1463 png_push_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32
1464 length)
1465 {
1466 png_uint_32 skip = 0;
1468 if (!(png_ptr->chunk_name[0] & 0x20))
1469 {
1470 #if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
1471 if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
1472 PNG_HANDLE_CHUNK_ALWAYS
1473 #if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
1474 && png_ptr->read_user_chunk_fn == NULL
1475 #endif
1476 )
1477 #endif
1478 png_chunk_error(png_ptr, "unknown critical chunk");
1480 info_ptr = info_ptr; /* to quiet some compiler warnings */
1481 }
1483 #if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
1484 if (png_ptr->flags & PNG_FLAG_KEEP_UNKNOWN_CHUNKS)
1485 {
1486 #ifdef PNG_MAX_MALLOC_64K
1487 if (length > (png_uint_32)65535L)
1488 {
1489 png_warning(png_ptr, "unknown chunk too large to fit in memory");
1490 skip = length - (png_uint_32)65535L;
1491 length = (png_uint_32)65535L;
1492 }
1493 #endif
1494 png_memcpy((png_charp)png_ptr->unknown_chunk.name,
1495 (png_charp)png_ptr->chunk_name,
1496 png_sizeof(png_ptr->unknown_chunk.name));
1497 png_ptr->unknown_chunk.name[png_sizeof(png_ptr->unknown_chunk.name) - 1]
1498 = '\0';
1500 png_ptr->unknown_chunk.size = (png_size_t)length;
1501 if (length == 0)
1502 png_ptr->unknown_chunk.data = NULL;
1503 else
1504 {
1505 png_ptr->unknown_chunk.data = (png_bytep)png_malloc(png_ptr,
1506 (png_uint_32)length);
1507 png_crc_read(png_ptr, (png_bytep)png_ptr->unknown_chunk.data, length);
1508 }
1509 #if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
1510 if (png_ptr->read_user_chunk_fn != NULL)
1511 {
1512 /* callback to user unknown chunk handler */
1513 int ret;
1514 ret = (*(png_ptr->read_user_chunk_fn))
1515 (png_ptr, &png_ptr->unknown_chunk);
1516 if (ret < 0)
1517 png_chunk_error(png_ptr, "error in user chunk");
1518 if (ret == 0)
1519 {
1520 if (!(png_ptr->chunk_name[0] & 0x20))
1521 if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
1522 PNG_HANDLE_CHUNK_ALWAYS)
1523 png_chunk_error(png_ptr, "unknown critical chunk");
1524 png_set_unknown_chunks(png_ptr, info_ptr,
1525 &png_ptr->unknown_chunk, 1);
1526 }
1527 }
1528 else
1529 #endif
1530 png_set_unknown_chunks(png_ptr, info_ptr, &png_ptr->unknown_chunk, 1);
1531 png_free(png_ptr, png_ptr->unknown_chunk.data);
1532 png_ptr->unknown_chunk.data = NULL;
1533 }
1534 else
1535 #endif
1536 skip=length;
1537 png_push_crc_skip(png_ptr, skip);
1538 }
1540 void /* PRIVATE */
1541 png_push_have_info(png_structp png_ptr, png_infop info_ptr)
1542 {
1543 if (png_ptr->info_fn != NULL)
1544 (*(png_ptr->info_fn))(png_ptr, info_ptr);
1545 }
1547 void /* PRIVATE */
1548 png_push_have_end(png_structp png_ptr, png_infop info_ptr)
1549 {
1550 if (png_ptr->end_fn != NULL)
1551 (*(png_ptr->end_fn))(png_ptr, info_ptr);
1552 }
1554 void /* PRIVATE */
1555 png_push_have_row(png_structp png_ptr, png_bytep row)
1556 {
1557 if (png_ptr->row_fn != NULL)
1558 (*(png_ptr->row_fn))(png_ptr, row, png_ptr->row_number,
1559 (int)png_ptr->pass);
1560 }
1562 void PNGAPI
1563 png_progressive_combine_row (png_structp png_ptr,
1564 png_bytep old_row, png_bytep new_row)
1565 {
1566 #ifdef PNG_USE_LOCAL_ARRAYS
1567 PNG_CONST int FARDATA png_pass_dsp_mask[7] =
1568 {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
1569 #endif
1570 if (png_ptr == NULL) return;
1571 if (new_row != NULL) /* new_row must == png_ptr->row_buf here. */
1572 png_combine_row(png_ptr, old_row, png_pass_dsp_mask[png_ptr->pass]);
1573 }
1575 void PNGAPI
1576 png_set_progressive_read_fn(png_structp png_ptr, png_voidp progressive_ptr,
1577 png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,
1578 png_progressive_end_ptr end_fn)
1579 {
1580 if (png_ptr == NULL) return;
1581 png_ptr->info_fn = info_fn;
1582 png_ptr->row_fn = row_fn;
1583 png_ptr->end_fn = end_fn;
1585 png_set_read_fn(png_ptr, progressive_ptr, png_push_fill_buffer);
1586 }
1588 png_voidp PNGAPI
1589 png_get_progressive_ptr(png_structp png_ptr)
1590 {
1591 if (png_ptr == NULL) return (NULL);
1592 return png_ptr->io_ptr;
1593 }
1594 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */