9f68f99023289b2b7ac006e67afcd3ac3ab1b3b6
[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 1.6.18 [July 23, 2015]
5 * Copyright (c) 1998-2015 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_READ_tEXt_MODE 4
23 #define PNG_READ_zTXt_MODE 5
24 #define PNG_READ_DONE_MODE 6
25 #define PNG_READ_iTXt_MODE 7
26 #define PNG_ERROR_MODE 8
27
28 #define PNG_PUSH_SAVE_BUFFER_IF_FULL \
29 if (png_ptr->push_length + 4 > png_ptr->buffer_size) \
30 { png_push_save_buffer(png_ptr); return; }
31 #define PNG_PUSH_SAVE_BUFFER_IF_LT(N) \
32 if (png_ptr->buffer_size < N) \
33 { png_push_save_buffer(png_ptr); return; }
34
35 void PNGAPI
36 png_process_data(png_structrp png_ptr, png_inforp info_ptr,
37 png_bytep buffer, png_size_t buffer_size)
38 {
39 if (png_ptr == NULL || info_ptr == NULL)
40 return;
41
42 png_push_restore_buffer(png_ptr, buffer, buffer_size);
43
44 while (png_ptr->buffer_size)
45 {
46 png_process_some_data(png_ptr, info_ptr);
47 }
48 }
49
50 png_size_t PNGAPI
51 png_process_data_pause(png_structrp png_ptr, int save)
52 {
53 if (png_ptr != NULL)
54 {
55 /* It's easiest for the caller if we do the save; then the caller doesn't
56 * have to supply the same data again:
57 */
58 if (save != 0)
59 png_push_save_buffer(png_ptr);
60 else
61 {
62 /* This includes any pending saved bytes: */
63 png_size_t remaining = png_ptr->buffer_size;
64 png_ptr->buffer_size = 0;
65
66 /* So subtract the saved buffer size, unless all the data
67 * is actually 'saved', in which case we just return 0
68 */
69 if (png_ptr->save_buffer_size < remaining)
70 return remaining - png_ptr->save_buffer_size;
71 }
72 }
73
74 return 0;
75 }
76
77 png_uint_32 PNGAPI
78 png_process_data_skip(png_structrp png_ptr)
79 {
80 /* TODO: Deprecate and remove this API.
81 * Somewhere the implementation of this seems to have been lost,
82 * or abandoned. It was only to support some internal back-door access
83 * to png_struct) in libpng-1.4.x.
84 */
85 png_app_warning(png_ptr,
86 "png_process_data_skip is not implemented in any current version of libpng");
87 return 0;
88 }
89
90 /* What we do with the incoming data depends on what we were previously
91 * doing before we ran out of data...
92 */
93 void /* PRIVATE */
94 png_process_some_data(png_structrp png_ptr, png_inforp info_ptr)
95 {
96 if (png_ptr == NULL)
97 return;
98
99 switch (png_ptr->process_mode)
100 {
101 case PNG_READ_SIG_MODE:
102 {
103 png_push_read_sig(png_ptr, info_ptr);
104 break;
105 }
106
107 case PNG_READ_CHUNK_MODE:
108 {
109 png_push_read_chunk(png_ptr, info_ptr);
110 break;
111 }
112
113 case PNG_READ_IDAT_MODE:
114 {
115 png_push_read_IDAT(png_ptr);
116 break;
117 }
118
119 default:
120 {
121 png_ptr->buffer_size = 0;
122 break;
123 }
124 }
125 }
126
127 /* Read any remaining signature bytes from the stream and compare them with
128 * the correct PNG signature. It is possible that this routine is called
129 * with bytes already read from the signature, either because they have been
130 * checked by the calling application, or because of multiple calls to this
131 * routine.
132 */
133 void /* PRIVATE */
134 png_push_read_sig(png_structrp png_ptr, png_inforp info_ptr)
135 {
136 png_size_t num_checked = png_ptr->sig_bytes, /* SAFE, does not exceed 8 */
137 num_to_check = 8 - num_checked;
138
139 if (png_ptr->buffer_size < num_to_check)
140 {
141 num_to_check = png_ptr->buffer_size;
142 }
143
144 png_push_fill_buffer(png_ptr, &(info_ptr->signature[num_checked]),
145 num_to_check);
146 png_ptr->sig_bytes = (png_byte)(png_ptr->sig_bytes + num_to_check);
147
148 if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
149 {
150 if (num_checked < 4 &&
151 png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
152 png_error(png_ptr, "Not a PNG file");
153
154 else
155 png_error(png_ptr, "PNG file corrupted by ASCII conversion");
156 }
157 else
158 {
159 if (png_ptr->sig_bytes >= 8)
160 {
161 png_ptr->process_mode = PNG_READ_CHUNK_MODE;
162 }
163 }
164 }
165
166 void /* PRIVATE */
167 png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
168 {
169 png_uint_32 chunk_name;
170 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
171 int keep; /* unknown handling method */
172 #endif
173
174 /* First we make sure we have enough data for the 4-byte chunk name
175 * and the 4-byte chunk length before proceeding with decoding the
176 * chunk data. To fully decode each of these chunks, we also make
177 * sure we have enough data in the buffer for the 4-byte CRC at the
178 * end of every chunk (except IDAT, which is handled separately).
179 */
180 if ((png_ptr->mode & PNG_HAVE_CHUNK_HEADER) == 0)
181 {
182 png_byte chunk_length[4];
183 png_byte chunk_tag[4];
184
185 PNG_PUSH_SAVE_BUFFER_IF_LT(8)
186 png_push_fill_buffer(png_ptr, chunk_length, 4);
187 png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
188 png_reset_crc(png_ptr);
189 png_crc_read(png_ptr, chunk_tag, 4);
190 png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag);
191 png_check_chunk_name(png_ptr, png_ptr->chunk_name);
192 png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
193 }
194
195 chunk_name = png_ptr->chunk_name;
196
197 if (chunk_name == png_IDAT)
198 {
199 if ((png_ptr->mode & PNG_AFTER_IDAT) != 0)
200 png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
201
202 /* If we reach an IDAT chunk, this means we have read all of the
203 * header chunks, and we can start reading the image (or if this
204 * is called after the image has been read - we have an error).
205 */
206 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
207 png_error(png_ptr, "Missing IHDR before IDAT");
208
209 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
210 (png_ptr->mode & PNG_HAVE_PLTE) == 0)
211 png_error(png_ptr, "Missing PLTE before IDAT");
212
213 png_ptr->mode |= PNG_HAVE_IDAT;
214 png_ptr->process_mode = PNG_READ_IDAT_MODE;
215
216 if ((png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) == 0)
217 if (png_ptr->push_length == 0)
218 return;
219
220 if ((png_ptr->mode & PNG_AFTER_IDAT) != 0)
221 png_benign_error(png_ptr, "Too many IDATs found");
222 }
223
224 if (chunk_name == png_IHDR)
225 {
226 if (png_ptr->push_length != 13)
227 png_error(png_ptr, "Invalid IHDR length");
228
229 PNG_PUSH_SAVE_BUFFER_IF_FULL
230 png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length);
231 }
232
233 else if (chunk_name == png_IEND)
234 {
235 PNG_PUSH_SAVE_BUFFER_IF_FULL
236 png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length);
237
238 png_ptr->process_mode = PNG_READ_DONE_MODE;
239 png_push_have_end(png_ptr, info_ptr);
240 }
241
242 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
243 else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0)
244 {
245 PNG_PUSH_SAVE_BUFFER_IF_FULL
246 png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length, keep);
247
248 if (chunk_name == png_PLTE)
249 png_ptr->mode |= PNG_HAVE_PLTE;
250 }
251 #endif
252
253 else if (chunk_name == png_PLTE)
254 {
255 PNG_PUSH_SAVE_BUFFER_IF_FULL
256 png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
257 }
258
259 else if (chunk_name == png_IDAT)
260 {
261 png_ptr->idat_size = png_ptr->push_length;
262 png_ptr->process_mode = PNG_READ_IDAT_MODE;
263 png_push_have_info(png_ptr, info_ptr);
264 png_ptr->zstream.avail_out =
265 (uInt) PNG_ROWBYTES(png_ptr->pixel_depth,
266 png_ptr->iwidth) + 1;
267 png_ptr->zstream.next_out = png_ptr->row_buf;
268 return;
269 }
270
271 #ifdef PNG_READ_gAMA_SUPPORTED
272 else if (png_ptr->chunk_name == png_gAMA)
273 {
274 PNG_PUSH_SAVE_BUFFER_IF_FULL
275 png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length);
276 }
277
278 #endif
279 #ifdef PNG_READ_sBIT_SUPPORTED
280 else if (png_ptr->chunk_name == png_sBIT)
281 {
282 PNG_PUSH_SAVE_BUFFER_IF_FULL
283 png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length);
284 }
285
286 #endif
287 #ifdef PNG_READ_cHRM_SUPPORTED
288 else if (png_ptr->chunk_name == png_cHRM)
289 {
290 PNG_PUSH_SAVE_BUFFER_IF_FULL
291 png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length);
292 }
293
294 #endif
295 #ifdef PNG_READ_sRGB_SUPPORTED
296 else if (chunk_name == png_sRGB)
297 {
298 PNG_PUSH_SAVE_BUFFER_IF_FULL
299 png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length);
300 }
301
302 #endif
303 #ifdef PNG_READ_iCCP_SUPPORTED
304 else if (png_ptr->chunk_name == png_iCCP)
305 {
306 PNG_PUSH_SAVE_BUFFER_IF_FULL
307 png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length);
308 }
309
310 #endif
311 #ifdef PNG_READ_sPLT_SUPPORTED
312 else if (chunk_name == png_sPLT)
313 {
314 PNG_PUSH_SAVE_BUFFER_IF_FULL
315 png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length);
316 }
317
318 #endif
319 #ifdef PNG_READ_tRNS_SUPPORTED
320 else if (chunk_name == png_tRNS)
321 {
322 PNG_PUSH_SAVE_BUFFER_IF_FULL
323 png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length);
324 }
325
326 #endif
327 #ifdef PNG_READ_bKGD_SUPPORTED
328 else if (chunk_name == png_bKGD)
329 {
330 PNG_PUSH_SAVE_BUFFER_IF_FULL
331 png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length);
332 }
333
334 #endif
335 #ifdef PNG_READ_hIST_SUPPORTED
336 else if (chunk_name == png_hIST)
337 {
338 PNG_PUSH_SAVE_BUFFER_IF_FULL
339 png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length);
340 }
341
342 #endif
343 #ifdef PNG_READ_pHYs_SUPPORTED
344 else if (chunk_name == png_pHYs)
345 {
346 PNG_PUSH_SAVE_BUFFER_IF_FULL
347 png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length);
348 }
349
350 #endif
351 #ifdef PNG_READ_oFFs_SUPPORTED
352 else if (chunk_name == png_oFFs)
353 {
354 PNG_PUSH_SAVE_BUFFER_IF_FULL
355 png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length);
356 }
357 #endif
358
359 #ifdef PNG_READ_pCAL_SUPPORTED
360 else if (chunk_name == png_pCAL)
361 {
362 PNG_PUSH_SAVE_BUFFER_IF_FULL
363 png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length);
364 }
365
366 #endif
367 #ifdef PNG_READ_sCAL_SUPPORTED
368 else if (chunk_name == png_sCAL)
369 {
370 PNG_PUSH_SAVE_BUFFER_IF_FULL
371 png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length);
372 }
373
374 #endif
375 #ifdef PNG_READ_tIME_SUPPORTED
376 else if (chunk_name == png_tIME)
377 {
378 PNG_PUSH_SAVE_BUFFER_IF_FULL
379 png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length);
380 }
381
382 #endif
383 #ifdef PNG_READ_tEXt_SUPPORTED
384 else if (chunk_name == png_tEXt)
385 {
386 PNG_PUSH_SAVE_BUFFER_IF_FULL
387 png_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length);
388 }
389
390 #endif
391 #ifdef PNG_READ_zTXt_SUPPORTED
392 else if (chunk_name == png_zTXt)
393 {
394 PNG_PUSH_SAVE_BUFFER_IF_FULL
395 png_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
396 }
397
398 #endif
399 #ifdef PNG_READ_iTXt_SUPPORTED
400 else if (chunk_name == png_iTXt)
401 {
402 PNG_PUSH_SAVE_BUFFER_IF_FULL
403 png_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
404 }
405 #endif
406
407 else
408 {
409 PNG_PUSH_SAVE_BUFFER_IF_FULL
410 png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length,
411 PNG_HANDLE_CHUNK_AS_DEFAULT);
412 }
413
414 png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
415 }
416
417 void PNGCBAPI
418 png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
419 {
420 png_bytep ptr;
421
422 if (png_ptr == NULL)
423 return;
424
425 ptr = buffer;
426 if (png_ptr->save_buffer_size != 0)
427 {
428 png_size_t save_size;
429
430 if (length < png_ptr->save_buffer_size)
431 save_size = length;
432
433 else
434 save_size = png_ptr->save_buffer_size;
435
436 memcpy(ptr, png_ptr->save_buffer_ptr, save_size);
437 length -= save_size;
438 ptr += save_size;
439 png_ptr->buffer_size -= save_size;
440 png_ptr->save_buffer_size -= save_size;
441 png_ptr->save_buffer_ptr += save_size;
442 }
443 if (length != 0 && png_ptr->current_buffer_size != 0)
444 {
445 png_size_t save_size;
446
447 if (length < png_ptr->current_buffer_size)
448 save_size = length;
449
450 else
451 save_size = png_ptr->current_buffer_size;
452
453 memcpy(ptr, png_ptr->current_buffer_ptr, save_size);
454 png_ptr->buffer_size -= save_size;
455 png_ptr->current_buffer_size -= save_size;
456 png_ptr->current_buffer_ptr += save_size;
457 }
458 }
459
460 void /* PRIVATE */
461 png_push_save_buffer(png_structrp png_ptr)
462 {
463 if (png_ptr->save_buffer_size != 0)
464 {
465 if (png_ptr->save_buffer_ptr != png_ptr->save_buffer)
466 {
467 png_size_t i, istop;
468 png_bytep sp;
469 png_bytep dp;
470
471 istop = png_ptr->save_buffer_size;
472 for (i = 0, sp = png_ptr->save_buffer_ptr, dp = png_ptr->save_buffer;
473 i < istop; i++, sp++, dp++)
474 {
475 *dp = *sp;
476 }
477 }
478 }
479 if (png_ptr->save_buffer_size + png_ptr->current_buffer_size >
480 png_ptr->save_buffer_max)
481 {
482 png_size_t new_max;
483 png_bytep old_buffer;
484
485 if (png_ptr->save_buffer_size > PNG_SIZE_MAX -
486 (png_ptr->current_buffer_size + 256))
487 {
488 png_error(png_ptr, "Potential overflow of save_buffer");
489 }
490
491 new_max = png_ptr->save_buffer_size + png_ptr->current_buffer_size + 256;
492 old_buffer = png_ptr->save_buffer;
493 png_ptr->save_buffer = (png_bytep)png_malloc_warn(png_ptr,
494 (png_size_t)new_max);
495
496 if (png_ptr->save_buffer == NULL)
497 {
498 png_free(png_ptr, old_buffer);
499 png_error(png_ptr, "Insufficient memory for save_buffer");
500 }
501
502 memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size);
503 png_free(png_ptr, old_buffer);
504 png_ptr->save_buffer_max = new_max;
505 }
506 if (png_ptr->current_buffer_size)
507 {
508 memcpy(png_ptr->save_buffer + png_ptr->save_buffer_size,
509 png_ptr->current_buffer_ptr, png_ptr->current_buffer_size);
510 png_ptr->save_buffer_size += png_ptr->current_buffer_size;
511 png_ptr->current_buffer_size = 0;
512 }
513 png_ptr->save_buffer_ptr = png_ptr->save_buffer;
514 png_ptr->buffer_size = 0;
515 }
516
517 void /* PRIVATE */
518 png_push_restore_buffer(png_structrp png_ptr, png_bytep buffer,
519 png_size_t buffer_length)
520 {
521 png_ptr->current_buffer = buffer;
522 png_ptr->current_buffer_size = buffer_length;
523 png_ptr->buffer_size = buffer_length + png_ptr->save_buffer_size;
524 png_ptr->current_buffer_ptr = png_ptr->current_buffer;
525 }
526
527 void /* PRIVATE */
528 png_push_read_IDAT(png_structrp png_ptr)
529 {
530 if ((png_ptr->mode & PNG_HAVE_CHUNK_HEADER) == 0)
531 {
532 png_byte chunk_length[4];
533 png_byte chunk_tag[4];
534
535 /* TODO: this code can be commoned up with the same code in push_read */
536 PNG_PUSH_SAVE_BUFFER_IF_LT(8)
537 png_push_fill_buffer(png_ptr, chunk_length, 4);
538 png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
539 png_reset_crc(png_ptr);
540 png_crc_read(png_ptr, chunk_tag, 4);
541 png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag);
542 png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
543
544 if (png_ptr->chunk_name != png_IDAT)
545 {
546 png_ptr->process_mode = PNG_READ_CHUNK_MODE;
547
548 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
549 png_error(png_ptr, "Not enough compressed data");
550
551 return;
552 }
553
554 png_ptr->idat_size = png_ptr->push_length;
555 }
556
557 if (png_ptr->idat_size != 0 && png_ptr->save_buffer_size != 0)
558 {
559 png_size_t save_size = png_ptr->save_buffer_size;
560 png_uint_32 idat_size = png_ptr->idat_size;
561
562 /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
563 * are of different types and we don't know which variable has the fewest
564 * bits. Carefully select the smaller and cast it to the type of the
565 * larger - this cannot overflow. Do not cast in the following test - it
566 * will break on either 16-bit or 64-bit platforms.
567 */
568 if (idat_size < save_size)
569 save_size = (png_size_t)idat_size;
570
571 else
572 idat_size = (png_uint_32)save_size;
573
574 png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
575
576 png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size);
577
578 png_ptr->idat_size -= idat_size;
579 png_ptr->buffer_size -= save_size;
580 png_ptr->save_buffer_size -= save_size;
581 png_ptr->save_buffer_ptr += save_size;
582 }
583
584 if (png_ptr->idat_size != 0 && png_ptr->current_buffer_size != 0)
585 {
586 png_size_t save_size = png_ptr->current_buffer_size;
587 png_uint_32 idat_size = png_ptr->idat_size;
588
589 /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
590 * are of different types and we don't know which variable has the fewest
591 * bits. Carefully select the smaller and cast it to the type of the
592 * larger - this cannot overflow.
593 */
594 if (idat_size < save_size)
595 save_size = (png_size_t)idat_size;
596
597 else
598 idat_size = (png_uint_32)save_size;
599
600 png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
601
602 png_process_IDAT_data(png_ptr, png_ptr->current_buffer_ptr, save_size);
603
604 png_ptr->idat_size -= idat_size;
605 png_ptr->buffer_size -= save_size;
606 png_ptr->current_buffer_size -= save_size;
607 png_ptr->current_buffer_ptr += save_size;
608 }
609
610 if (png_ptr->idat_size == 0)
611 {
612 PNG_PUSH_SAVE_BUFFER_IF_LT(4)
613 png_crc_finish(png_ptr, 0);
614 png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
615 png_ptr->mode |= PNG_AFTER_IDAT;
616 png_ptr->zowner = 0;
617 }
618 }
619
620 void /* PRIVATE */
621 png_process_IDAT_data(png_structrp png_ptr, png_bytep buffer,
622 png_size_t buffer_length)
623 {
624 /* The caller checks for a non-zero buffer length. */
625 if (!(buffer_length > 0) || buffer == NULL)
626 png_error(png_ptr, "No IDAT data (internal error)");
627
628 /* This routine must process all the data it has been given
629 * before returning, calling the row callback as required to
630 * handle the uncompressed results.
631 */
632 png_ptr->zstream.next_in = buffer;
633 /* TODO: WARNING: TRUNCATION ERROR: DANGER WILL ROBINSON: */
634 png_ptr->zstream.avail_in = (uInt)buffer_length;
635
636 /* Keep going until the decompressed data is all processed
637 * or the stream marked as finished.
638 */
639 while (png_ptr->zstream.avail_in > 0 &&
640 (png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
641 {
642 int ret;
643
644 /* We have data for zlib, but we must check that zlib
645 * has someplace to put the results. It doesn't matter
646 * if we don't expect any results -- it may be the input
647 * data is just the LZ end code.
648 */
649 if (!(png_ptr->zstream.avail_out > 0))
650 {
651 /* TODO: WARNING: TRUNCATION ERROR: DANGER WILL ROBINSON: */
652 png_ptr->zstream.avail_out = (uInt)(PNG_ROWBYTES(png_ptr->pixel_depth,
653 png_ptr->iwidth) + 1);
654
655 png_ptr->zstream.next_out = png_ptr->row_buf;
656 }
657
658 /* Using Z_SYNC_FLUSH here means that an unterminated
659 * LZ stream (a stream with a missing end code) can still
660 * be handled, otherwise (Z_NO_FLUSH) a future zlib
661 * implementation might defer output and therefore
662 * change the current behavior (see comments in inflate.c
663 * for why this doesn't happen at present with zlib 1.2.5).
664 */
665 ret = inflate(&png_ptr->zstream, Z_SYNC_FLUSH);
666
667 /* Check for any failure before proceeding. */
668 if (ret != Z_OK && ret != Z_STREAM_END)
669 {
670 /* Terminate the decompression. */
671 png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
672 png_ptr->zowner = 0;
673
674 /* This may be a truncated stream (missing or
675 * damaged end code). Treat that as a warning.
676 */
677 if (png_ptr->row_number >= png_ptr->num_rows ||
678 png_ptr->pass > 6)
679 png_warning(png_ptr, "Truncated compressed data in IDAT");
680
681 else
682 png_error(png_ptr, "Decompression error in IDAT");
683
684 /* Skip the check on unprocessed input */
685 return;
686 }
687
688 /* Did inflate output any data? */
689 if (png_ptr->zstream.next_out != png_ptr->row_buf)
690 {
691 /* Is this unexpected data after the last row?
692 * If it is, artificially terminate the LZ output
693 * here.
694 */
695 if (png_ptr->row_number >= png_ptr->num_rows ||
696 png_ptr->pass > 6)
697 {
698 /* Extra data. */
699 png_warning(png_ptr, "Extra compressed data in IDAT");
700 png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
701 png_ptr->zowner = 0;
702
703 /* Do no more processing; skip the unprocessed
704 * input check below.
705 */
706 return;
707 }
708
709 /* Do we have a complete row? */
710 if (png_ptr->zstream.avail_out == 0)
711 png_push_process_row(png_ptr);
712 }
713
714 /* And check for the end of the stream. */
715 if (ret == Z_STREAM_END)
716 png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
717 }
718
719 /* All the data should have been processed, if anything
720 * is left at this point we have bytes of IDAT data
721 * after the zlib end code.
722 */
723 if (png_ptr->zstream.avail_in > 0)
724 png_warning(png_ptr, "Extra compression data in IDAT");
725 }
726
727 void /* PRIVATE */
728 png_push_process_row(png_structrp png_ptr)
729 {
730 /* 1.5.6: row_info moved out of png_struct to a local here. */
731 png_row_info row_info;
732
733 row_info.width = png_ptr->iwidth; /* NOTE: width of current interlaced row */
734 row_info.color_type = png_ptr->color_type;
735 row_info.bit_depth = png_ptr->bit_depth;
736 row_info.channels = png_ptr->channels;
737 row_info.pixel_depth = png_ptr->pixel_depth;
738 row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
739
740 if (png_ptr->row_buf[0] > PNG_FILTER_VALUE_NONE)
741 {
742 if (png_ptr->row_buf[0] < PNG_FILTER_VALUE_LAST)
743 png_read_filter_row(png_ptr, &row_info, png_ptr->row_buf + 1,
744 png_ptr->prev_row + 1, png_ptr->row_buf[0]);
745 else
746 png_error(png_ptr, "bad adaptive filter value");
747 }
748
749 /* libpng 1.5.6: the following line was copying png_ptr->rowbytes before
750 * 1.5.6, while the buffer really is this big in current versions of libpng
751 * it may not be in the future, so this was changed just to copy the
752 * interlaced row count:
753 */
754 memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1);
755
756 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
757 if (png_ptr->transformations != 0)
758 png_do_read_transformations(png_ptr, &row_info);
759 #endif
760
761 /* The transformed pixel depth should match the depth now in row_info. */
762 if (png_ptr->transformed_pixel_depth == 0)
763 {
764 png_ptr->transformed_pixel_depth = row_info.pixel_depth;
765 if (row_info.pixel_depth > png_ptr->maximum_pixel_depth)
766 png_error(png_ptr, "progressive row overflow");
767 }
768
769 else if (png_ptr->transformed_pixel_depth != row_info.pixel_depth)
770 png_error(png_ptr, "internal progressive row size calculation error");
771
772
773 #ifdef PNG_READ_INTERLACING_SUPPORTED
774 /* Expand interlaced rows to full size */
775 if (png_ptr->interlaced != 0 &&
776 (png_ptr->transformations & PNG_INTERLACE) != 0)
777 {
778 if (png_ptr->pass < 6)
779 png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass,
780 png_ptr->transformations);
781
782 switch (png_ptr->pass)
783 {
784 case 0:
785 {
786 int i;
787 for (i = 0; i < 8 && png_ptr->pass == 0; i++)
788 {
789 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
790 png_read_push_finish_row(png_ptr); /* Updates png_ptr->pass */
791 }
792
793 if (png_ptr->pass == 2) /* Pass 1 might be empty */
794 {
795 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
796 {
797 png_push_have_row(png_ptr, NULL);
798 png_read_push_finish_row(png_ptr);
799 }
800 }
801
802 if (png_ptr->pass == 4 && png_ptr->height <= 4)
803 {
804 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
805 {
806 png_push_have_row(png_ptr, NULL);
807 png_read_push_finish_row(png_ptr);
808 }
809 }
810
811 if (png_ptr->pass == 6 && png_ptr->height <= 4)
812 {
813 png_push_have_row(png_ptr, NULL);
814 png_read_push_finish_row(png_ptr);
815 }
816
817 break;
818 }
819
820 case 1:
821 {
822 int i;
823 for (i = 0; i < 8 && png_ptr->pass == 1; i++)
824 {
825 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
826 png_read_push_finish_row(png_ptr);
827 }
828
829 if (png_ptr->pass == 2) /* Skip top 4 generated rows */
830 {
831 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
832 {
833 png_push_have_row(png_ptr, NULL);
834 png_read_push_finish_row(png_ptr);
835 }
836 }
837
838 break;
839 }
840
841 case 2:
842 {
843 int i;
844
845 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
846 {
847 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
848 png_read_push_finish_row(png_ptr);
849 }
850
851 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
852 {
853 png_push_have_row(png_ptr, NULL);
854 png_read_push_finish_row(png_ptr);
855 }
856
857 if (png_ptr->pass == 4) /* Pass 3 might be empty */
858 {
859 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
860 {
861 png_push_have_row(png_ptr, NULL);
862 png_read_push_finish_row(png_ptr);
863 }
864 }
865
866 break;
867 }
868
869 case 3:
870 {
871 int i;
872
873 for (i = 0; i < 4 && png_ptr->pass == 3; i++)
874 {
875 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
876 png_read_push_finish_row(png_ptr);
877 }
878
879 if (png_ptr->pass == 4) /* Skip top two generated rows */
880 {
881 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
882 {
883 png_push_have_row(png_ptr, NULL);
884 png_read_push_finish_row(png_ptr);
885 }
886 }
887
888 break;
889 }
890
891 case 4:
892 {
893 int i;
894
895 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
896 {
897 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
898 png_read_push_finish_row(png_ptr);
899 }
900
901 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
902 {
903 png_push_have_row(png_ptr, NULL);
904 png_read_push_finish_row(png_ptr);
905 }
906
907 if (png_ptr->pass == 6) /* Pass 5 might be empty */
908 {
909 png_push_have_row(png_ptr, NULL);
910 png_read_push_finish_row(png_ptr);
911 }
912
913 break;
914 }
915
916 case 5:
917 {
918 int i;
919
920 for (i = 0; i < 2 && png_ptr->pass == 5; i++)
921 {
922 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
923 png_read_push_finish_row(png_ptr);
924 }
925
926 if (png_ptr->pass == 6) /* Skip top generated row */
927 {
928 png_push_have_row(png_ptr, NULL);
929 png_read_push_finish_row(png_ptr);
930 }
931
932 break;
933 }
934
935 default:
936 case 6:
937 {
938 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
939 png_read_push_finish_row(png_ptr);
940
941 if (png_ptr->pass != 6)
942 break;
943
944 png_push_have_row(png_ptr, NULL);
945 png_read_push_finish_row(png_ptr);
946 }
947 }
948 }
949 else
950 #endif
951 {
952 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
953 png_read_push_finish_row(png_ptr);
954 }
955 }
956
957 void /* PRIVATE */
958 png_read_push_finish_row(png_structrp png_ptr)
959 {
960 #ifdef PNG_READ_INTERLACING_SUPPORTED
961 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
962
963 /* Start of interlace block */
964 static PNG_CONST png_byte png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
965
966 /* Offset to next interlace block */
967 static PNG_CONST png_byte png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
968
969 /* Start of interlace block in the y direction */
970 static PNG_CONST png_byte png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
971
972 /* Offset to next interlace block in the y direction */
973 static PNG_CONST png_byte png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
974
975 /* Height of interlace block. This is not currently used - if you need
976 * it, uncomment it here and in png.h
977 static PNG_CONST png_byte png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
978 */
979 #endif
980
981 png_ptr->row_number++;
982 if (png_ptr->row_number < png_ptr->num_rows)
983 return;
984
985 #ifdef PNG_READ_INTERLACING_SUPPORTED
986 if (png_ptr->interlaced != 0)
987 {
988 png_ptr->row_number = 0;
989 memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
990
991 do
992 {
993 png_ptr->pass++;
994 if ((png_ptr->pass == 1 && png_ptr->width < 5) ||
995 (png_ptr->pass == 3 && png_ptr->width < 3) ||
996 (png_ptr->pass == 5 && png_ptr->width < 2))
997 png_ptr->pass++;
998
999 if (png_ptr->pass > 7)
1000 png_ptr->pass--;
1001
1002 if (png_ptr->pass >= 7)
1003 break;
1004
1005 png_ptr->iwidth = (png_ptr->width +
1006 png_pass_inc[png_ptr->pass] - 1 -
1007 png_pass_start[png_ptr->pass]) /
1008 png_pass_inc[png_ptr->pass];
1009
1010 if ((png_ptr->transformations & PNG_INTERLACE) != 0)
1011 break;
1012
1013 png_ptr->num_rows = (png_ptr->height +
1014 png_pass_yinc[png_ptr->pass] - 1 -
1015 png_pass_ystart[png_ptr->pass]) /
1016 png_pass_yinc[png_ptr->pass];
1017
1018 } while (png_ptr->iwidth == 0 || png_ptr->num_rows == 0);
1019 }
1020 #endif /* READ_INTERLACING */
1021 }
1022
1023 void /* PRIVATE */
1024 png_push_have_info(png_structrp png_ptr, png_inforp info_ptr)
1025 {
1026 if (png_ptr->info_fn != NULL)
1027 (*(png_ptr->info_fn))(png_ptr, info_ptr);
1028 }
1029
1030 void /* PRIVATE */
1031 png_push_have_end(png_structrp png_ptr, png_inforp info_ptr)
1032 {
1033 if (png_ptr->end_fn != NULL)
1034 (*(png_ptr->end_fn))(png_ptr, info_ptr);
1035 }
1036
1037 void /* PRIVATE */
1038 png_push_have_row(png_structrp png_ptr, png_bytep row)
1039 {
1040 if (png_ptr->row_fn != NULL)
1041 (*(png_ptr->row_fn))(png_ptr, row, png_ptr->row_number,
1042 (int)png_ptr->pass);
1043 }
1044
1045 #ifdef PNG_READ_INTERLACING_SUPPORTED
1046 void PNGAPI
1047 png_progressive_combine_row(png_const_structrp png_ptr, png_bytep old_row,
1048 png_const_bytep new_row)
1049 {
1050 if (png_ptr == NULL)
1051 return;
1052
1053 /* new_row is a flag here - if it is NULL then the app callback was called
1054 * from an empty row (see the calls to png_struct::row_fn below), otherwise
1055 * it must be png_ptr->row_buf+1
1056 */
1057 if (new_row != NULL)
1058 png_combine_row(png_ptr, old_row, 1/*blocky display*/);
1059 }
1060 #endif /* READ_INTERLACING */
1061
1062 void PNGAPI
1063 png_set_progressive_read_fn(png_structrp png_ptr, png_voidp progressive_ptr,
1064 png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,
1065 png_progressive_end_ptr end_fn)
1066 {
1067 if (png_ptr == NULL)
1068 return;
1069
1070 png_ptr->info_fn = info_fn;
1071 png_ptr->row_fn = row_fn;
1072 png_ptr->end_fn = end_fn;
1073
1074 png_set_read_fn(png_ptr, progressive_ptr, png_push_fill_buffer);
1075 }
1076
1077 png_voidp PNGAPI
1078 png_get_progressive_ptr(png_const_structrp png_ptr)
1079 {
1080 if (png_ptr == NULL)
1081 return (NULL);
1082
1083 return png_ptr->io_ptr;
1084 }
1085 #endif /* PROGRESSIVE_READ */