1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation. Oracle designates this
7 * particular file as subject to the "Classpath" exception as provided
8 * by Oracle in the LICENSE file that accompanied this code.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 */
24
25 /* pngpread.c - read a png file in push mode
26 *
27 * This file is available under and governed by the GNU General Public
28 * License version 2 only, as published by the Free Software Foundation.
29 * However, the following notice accompanied the original version of this
30 * file and, per its terms, should not be removed:
31 *
32 * Last changed in libpng 1.6.35 [July 15, 2018]
33 * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
34 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
35 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
36 *
37 * This code is released under the libpng license.
38 * For conditions of distribution and use, see the disclaimer
39 * and license in png.h
40 */
41
42 #include "pngpriv.h"
43
44 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
45
46 /* Push model modes */
47 #define PNG_READ_SIG_MODE 0
48 #define PNG_READ_CHUNK_MODE 1
49 #define PNG_READ_IDAT_MODE 2
50 #define PNG_READ_tEXt_MODE 4
51 #define PNG_READ_zTXt_MODE 5
52 #define PNG_READ_DONE_MODE 6
53 #define PNG_READ_iTXt_MODE 7
54 #define PNG_ERROR_MODE 8
55
56 #define PNG_PUSH_SAVE_BUFFER_IF_FULL \
57 if (png_ptr->push_length + 4 > png_ptr->buffer_size) \
58 { png_push_save_buffer(png_ptr); return; }
59 #define PNG_PUSH_SAVE_BUFFER_IF_LT(N) \
60 if (png_ptr->buffer_size < N) \
61 { png_push_save_buffer(png_ptr); return; }
62
63 void PNGAPI
64 png_process_data(png_structrp png_ptr, png_inforp info_ptr,
65 png_bytep buffer, size_t buffer_size)
66 {
67 if (png_ptr == NULL || info_ptr == NULL)
68 return;
69
70 png_push_restore_buffer(png_ptr, buffer, buffer_size);
71
72 while (png_ptr->buffer_size)
73 {
74 png_process_some_data(png_ptr, info_ptr);
75 }
76 }
77
78 size_t PNGAPI
79 png_process_data_pause(png_structrp png_ptr, int save)
80 {
81 if (png_ptr != NULL)
82 {
83 /* It's easiest for the caller if we do the save; then the caller doesn't
84 * have to supply the same data again:
85 */
86 if (save != 0)
87 png_push_save_buffer(png_ptr);
88 else
89 {
90 /* This includes any pending saved bytes: */
91 size_t remaining = png_ptr->buffer_size;
92 png_ptr->buffer_size = 0;
93
94 /* So subtract the saved buffer size, unless all the data
95 * is actually 'saved', in which case we just return 0
96 */
97 if (png_ptr->save_buffer_size < remaining)
98 return remaining - png_ptr->save_buffer_size;
99 }
100 }
101
102 return 0;
103 }
104
105 png_uint_32 PNGAPI
106 png_process_data_skip(png_structrp png_ptr)
107 {
108 /* TODO: Deprecate and remove this API.
109 * Somewhere the implementation of this seems to have been lost,
110 * or abandoned. It was only to support some internal back-door access
111 * to png_struct) in libpng-1.4.x.
112 */
113 png_app_warning(png_ptr,
114 "png_process_data_skip is not implemented in any current version of libpng");
115 return 0;
116 }
117
118 /* What we do with the incoming data depends on what we were previously
119 * doing before we ran out of data...
120 */
121 void /* PRIVATE */
122 png_process_some_data(png_structrp png_ptr, png_inforp info_ptr)
123 {
124 if (png_ptr == NULL)
125 return;
126
127 switch (png_ptr->process_mode)
128 {
129 case PNG_READ_SIG_MODE:
130 {
131 png_push_read_sig(png_ptr, info_ptr);
132 break;
133 }
134
135 case PNG_READ_CHUNK_MODE:
136 {
137 png_push_read_chunk(png_ptr, info_ptr);
138 break;
139 }
140
141 case PNG_READ_IDAT_MODE:
142 {
143 png_push_read_IDAT(png_ptr);
144 break;
145 }
146
147 default:
148 {
149 png_ptr->buffer_size = 0;
150 break;
151 }
152 }
153 }
154
155 /* Read any remaining signature bytes from the stream and compare them with
156 * the correct PNG signature. It is possible that this routine is called
157 * with bytes already read from the signature, either because they have been
158 * checked by the calling application, or because of multiple calls to this
159 * routine.
160 */
161 void /* PRIVATE */
162 png_push_read_sig(png_structrp png_ptr, png_inforp info_ptr)
163 {
164 size_t num_checked = png_ptr->sig_bytes; /* SAFE, does not exceed 8 */
165 size_t num_to_check = 8 - num_checked;
166
167 if (png_ptr->buffer_size < num_to_check)
168 {
169 num_to_check = png_ptr->buffer_size;
170 }
171
172 png_push_fill_buffer(png_ptr, &(info_ptr->signature[num_checked]),
173 num_to_check);
174 png_ptr->sig_bytes = (png_byte)(png_ptr->sig_bytes + num_to_check);
175
176 if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
177 {
178 if (num_checked < 4 &&
179 png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
180 png_error(png_ptr, "Not a PNG file");
181
182 else
183 png_error(png_ptr, "PNG file corrupted by ASCII conversion");
184 }
185 else
186 {
187 if (png_ptr->sig_bytes >= 8)
188 {
189 png_ptr->process_mode = PNG_READ_CHUNK_MODE;
190 }
191 }
192 }
193
194 void /* PRIVATE */
195 png_push_read_chunk(png_structrp png_ptr, png_inforp info_ptr)
196 {
197 png_uint_32 chunk_name;
198 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
199 int keep; /* unknown handling method */
200 #endif
201
202 /* First we make sure we have enough data for the 4-byte chunk name
203 * and the 4-byte chunk length before proceeding with decoding the
204 * chunk data. To fully decode each of these chunks, we also make
205 * sure we have enough data in the buffer for the 4-byte CRC at the
206 * end of every chunk (except IDAT, which is handled separately).
207 */
208 if ((png_ptr->mode & PNG_HAVE_CHUNK_HEADER) == 0)
209 {
210 png_byte chunk_length[4];
211 png_byte chunk_tag[4];
212
213 PNG_PUSH_SAVE_BUFFER_IF_LT(8)
214 png_push_fill_buffer(png_ptr, chunk_length, 4);
215 png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
216 png_reset_crc(png_ptr);
217 png_crc_read(png_ptr, chunk_tag, 4);
218 png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag);
219 png_check_chunk_name(png_ptr, png_ptr->chunk_name);
220 png_check_chunk_length(png_ptr, png_ptr->push_length);
221 png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
222 }
223
224 chunk_name = png_ptr->chunk_name;
225
226 if (chunk_name == png_IDAT)
227 {
228 if ((png_ptr->mode & PNG_AFTER_IDAT) != 0)
229 png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
230
231 /* If we reach an IDAT chunk, this means we have read all of the
232 * header chunks, and we can start reading the image (or if this
233 * is called after the image has been read - we have an error).
234 */
235 if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
236 png_error(png_ptr, "Missing IHDR before IDAT");
237
238 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
239 (png_ptr->mode & PNG_HAVE_PLTE) == 0)
240 png_error(png_ptr, "Missing PLTE before IDAT");
241
242 png_ptr->process_mode = PNG_READ_IDAT_MODE;
243
244 if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
245 if ((png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) == 0)
246 if (png_ptr->push_length == 0)
247 return;
248
249 png_ptr->mode |= PNG_HAVE_IDAT;
250
251 if ((png_ptr->mode & PNG_AFTER_IDAT) != 0)
252 png_benign_error(png_ptr, "Too many IDATs found");
253 }
254
255 if (chunk_name == png_IHDR)
256 {
257 if (png_ptr->push_length != 13)
258 png_error(png_ptr, "Invalid IHDR length");
259
260 PNG_PUSH_SAVE_BUFFER_IF_FULL
261 png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length);
262 }
263
264 else if (chunk_name == png_IEND)
265 {
266 PNG_PUSH_SAVE_BUFFER_IF_FULL
267 png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length);
268
269 png_ptr->process_mode = PNG_READ_DONE_MODE;
270 png_push_have_end(png_ptr, info_ptr);
271 }
272
273 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
274 else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0)
275 {
276 PNG_PUSH_SAVE_BUFFER_IF_FULL
277 png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length, keep);
278
279 if (chunk_name == png_PLTE)
280 png_ptr->mode |= PNG_HAVE_PLTE;
281 }
282 #endif
283
284 else if (chunk_name == png_PLTE)
285 {
286 PNG_PUSH_SAVE_BUFFER_IF_FULL
287 png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
288 }
289
290 else if (chunk_name == png_IDAT)
291 {
292 png_ptr->idat_size = png_ptr->push_length;
293 png_ptr->process_mode = PNG_READ_IDAT_MODE;
294 png_push_have_info(png_ptr, info_ptr);
295 png_ptr->zstream.avail_out =
296 (uInt) PNG_ROWBYTES(png_ptr->pixel_depth,
297 png_ptr->iwidth) + 1;
298 png_ptr->zstream.next_out = png_ptr->row_buf;
299 return;
300 }
301
302 #ifdef PNG_READ_gAMA_SUPPORTED
303 else if (png_ptr->chunk_name == png_gAMA)
304 {
305 PNG_PUSH_SAVE_BUFFER_IF_FULL
306 png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length);
307 }
308
309 #endif
310 #ifdef PNG_READ_sBIT_SUPPORTED
311 else if (png_ptr->chunk_name == png_sBIT)
312 {
313 PNG_PUSH_SAVE_BUFFER_IF_FULL
314 png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length);
315 }
316
317 #endif
318 #ifdef PNG_READ_cHRM_SUPPORTED
319 else if (png_ptr->chunk_name == png_cHRM)
320 {
321 PNG_PUSH_SAVE_BUFFER_IF_FULL
322 png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length);
323 }
324
325 #endif
326 #ifdef PNG_READ_sRGB_SUPPORTED
327 else if (chunk_name == png_sRGB)
328 {
329 PNG_PUSH_SAVE_BUFFER_IF_FULL
330 png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length);
331 }
332
333 #endif
334 #ifdef PNG_READ_iCCP_SUPPORTED
335 else if (png_ptr->chunk_name == png_iCCP)
336 {
337 PNG_PUSH_SAVE_BUFFER_IF_FULL
338 png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length);
339 }
340
341 #endif
342 #ifdef PNG_READ_sPLT_SUPPORTED
343 else if (chunk_name == png_sPLT)
344 {
345 PNG_PUSH_SAVE_BUFFER_IF_FULL
346 png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length);
347 }
348
349 #endif
350 #ifdef PNG_READ_tRNS_SUPPORTED
351 else if (chunk_name == png_tRNS)
352 {
353 PNG_PUSH_SAVE_BUFFER_IF_FULL
354 png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length);
355 }
356
357 #endif
358 #ifdef PNG_READ_bKGD_SUPPORTED
359 else if (chunk_name == png_bKGD)
360 {
361 PNG_PUSH_SAVE_BUFFER_IF_FULL
362 png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length);
363 }
364
365 #endif
366 #ifdef PNG_READ_hIST_SUPPORTED
367 else if (chunk_name == png_hIST)
368 {
369 PNG_PUSH_SAVE_BUFFER_IF_FULL
370 png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length);
371 }
372
373 #endif
374 #ifdef PNG_READ_pHYs_SUPPORTED
375 else if (chunk_name == png_pHYs)
376 {
377 PNG_PUSH_SAVE_BUFFER_IF_FULL
378 png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length);
379 }
380
381 #endif
382 #ifdef PNG_READ_oFFs_SUPPORTED
383 else if (chunk_name == png_oFFs)
384 {
385 PNG_PUSH_SAVE_BUFFER_IF_FULL
386 png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length);
387 }
388 #endif
389
390 #ifdef PNG_READ_pCAL_SUPPORTED
391 else if (chunk_name == png_pCAL)
392 {
393 PNG_PUSH_SAVE_BUFFER_IF_FULL
394 png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length);
395 }
396
397 #endif
398 #ifdef PNG_READ_sCAL_SUPPORTED
399 else if (chunk_name == png_sCAL)
400 {
401 PNG_PUSH_SAVE_BUFFER_IF_FULL
402 png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length);
403 }
404
405 #endif
406 #ifdef PNG_READ_tIME_SUPPORTED
407 else if (chunk_name == png_tIME)
408 {
409 PNG_PUSH_SAVE_BUFFER_IF_FULL
410 png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length);
411 }
412
413 #endif
414 #ifdef PNG_READ_tEXt_SUPPORTED
415 else if (chunk_name == png_tEXt)
416 {
417 PNG_PUSH_SAVE_BUFFER_IF_FULL
418 png_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length);
419 }
420
421 #endif
422 #ifdef PNG_READ_zTXt_SUPPORTED
423 else if (chunk_name == png_zTXt)
424 {
425 PNG_PUSH_SAVE_BUFFER_IF_FULL
426 png_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
427 }
428
429 #endif
430 #ifdef PNG_READ_iTXt_SUPPORTED
431 else if (chunk_name == png_iTXt)
432 {
433 PNG_PUSH_SAVE_BUFFER_IF_FULL
434 png_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
435 }
436 #endif
437
438 else
439 {
440 PNG_PUSH_SAVE_BUFFER_IF_FULL
441 png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length,
442 PNG_HANDLE_CHUNK_AS_DEFAULT);
443 }
444
445 png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
446 }
447
448 void PNGCBAPI
449 png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, size_t length)
450 {
451 png_bytep ptr;
452
453 if (png_ptr == NULL)
454 return;
455
456 ptr = buffer;
457 if (png_ptr->save_buffer_size != 0)
458 {
459 size_t save_size;
460
461 if (length < png_ptr->save_buffer_size)
462 save_size = length;
463
464 else
465 save_size = png_ptr->save_buffer_size;
466
467 memcpy(ptr, png_ptr->save_buffer_ptr, save_size);
468 length -= save_size;
469 ptr += save_size;
470 png_ptr->buffer_size -= save_size;
471 png_ptr->save_buffer_size -= save_size;
472 png_ptr->save_buffer_ptr += save_size;
473 }
474 if (length != 0 && png_ptr->current_buffer_size != 0)
475 {
476 size_t save_size;
477
478 if (length < png_ptr->current_buffer_size)
479 save_size = length;
480
481 else
482 save_size = png_ptr->current_buffer_size;
483
484 memcpy(ptr, png_ptr->current_buffer_ptr, save_size);
485 png_ptr->buffer_size -= save_size;
486 png_ptr->current_buffer_size -= save_size;
487 png_ptr->current_buffer_ptr += save_size;
488 }
489 }
490
491 void /* PRIVATE */
492 png_push_save_buffer(png_structrp png_ptr)
493 {
494 if (png_ptr->save_buffer_size != 0)
495 {
496 if (png_ptr->save_buffer_ptr != png_ptr->save_buffer)
497 {
498 size_t i, istop;
499 png_bytep sp;
500 png_bytep dp;
501
502 istop = png_ptr->save_buffer_size;
503 for (i = 0, sp = png_ptr->save_buffer_ptr, dp = png_ptr->save_buffer;
504 i < istop; i++, sp++, dp++)
505 {
506 *dp = *sp;
507 }
508 }
509 }
510 if (png_ptr->save_buffer_size + png_ptr->current_buffer_size >
511 png_ptr->save_buffer_max)
512 {
513 size_t new_max;
514 png_bytep old_buffer;
515
516 if (png_ptr->save_buffer_size > PNG_SIZE_MAX -
517 (png_ptr->current_buffer_size + 256))
518 {
519 png_error(png_ptr, "Potential overflow of save_buffer");
520 }
521
522 new_max = png_ptr->save_buffer_size + png_ptr->current_buffer_size + 256;
523 old_buffer = png_ptr->save_buffer;
524 png_ptr->save_buffer = (png_bytep)png_malloc_warn(png_ptr,
525 (size_t)new_max);
526
527 if (png_ptr->save_buffer == NULL)
528 {
529 png_free(png_ptr, old_buffer);
530 png_error(png_ptr, "Insufficient memory for save_buffer");
531 }
532
533 if (old_buffer)
534 memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size);
535 else if (png_ptr->save_buffer_size)
536 png_error(png_ptr, "save_buffer error");
537 png_free(png_ptr, old_buffer);
538 png_ptr->save_buffer_max = new_max;
539 }
540 if (png_ptr->current_buffer_size)
541 {
542 memcpy(png_ptr->save_buffer + png_ptr->save_buffer_size,
543 png_ptr->current_buffer_ptr, png_ptr->current_buffer_size);
544 png_ptr->save_buffer_size += png_ptr->current_buffer_size;
545 png_ptr->current_buffer_size = 0;
546 }
547 png_ptr->save_buffer_ptr = png_ptr->save_buffer;
548 png_ptr->buffer_size = 0;
549 }
550
551 void /* PRIVATE */
552 png_push_restore_buffer(png_structrp png_ptr, png_bytep buffer,
553 size_t buffer_length)
554 {
555 png_ptr->current_buffer = buffer;
556 png_ptr->current_buffer_size = buffer_length;
557 png_ptr->buffer_size = buffer_length + png_ptr->save_buffer_size;
558 png_ptr->current_buffer_ptr = png_ptr->current_buffer;
559 }
560
561 void /* PRIVATE */
562 png_push_read_IDAT(png_structrp png_ptr)
563 {
564 if ((png_ptr->mode & PNG_HAVE_CHUNK_HEADER) == 0)
565 {
566 png_byte chunk_length[4];
567 png_byte chunk_tag[4];
568
569 /* TODO: this code can be commoned up with the same code in push_read */
570 PNG_PUSH_SAVE_BUFFER_IF_LT(8)
571 png_push_fill_buffer(png_ptr, chunk_length, 4);
572 png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
573 png_reset_crc(png_ptr);
574 png_crc_read(png_ptr, chunk_tag, 4);
575 png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag);
576 png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
577
578 if (png_ptr->chunk_name != png_IDAT)
579 {
580 png_ptr->process_mode = PNG_READ_CHUNK_MODE;
581
582 if ((png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
583 png_error(png_ptr, "Not enough compressed data");
584
585 return;
586 }
587
588 png_ptr->idat_size = png_ptr->push_length;
589 }
590
591 if (png_ptr->idat_size != 0 && png_ptr->save_buffer_size != 0)
592 {
593 size_t save_size = png_ptr->save_buffer_size;
594 png_uint_32 idat_size = png_ptr->idat_size;
595
596 /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
597 * are of different types and we don't know which variable has the fewest
598 * bits. Carefully select the smaller and cast it to the type of the
599 * larger - this cannot overflow. Do not cast in the following test - it
600 * will break on either 16-bit or 64-bit platforms.
601 */
602 if (idat_size < save_size)
603 save_size = (size_t)idat_size;
604
605 else
606 idat_size = (png_uint_32)save_size;
607
608 png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
609
610 png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size);
611
612 png_ptr->idat_size -= idat_size;
613 png_ptr->buffer_size -= save_size;
614 png_ptr->save_buffer_size -= save_size;
615 png_ptr->save_buffer_ptr += save_size;
616 }
617
618 if (png_ptr->idat_size != 0 && png_ptr->current_buffer_size != 0)
619 {
620 size_t save_size = png_ptr->current_buffer_size;
621 png_uint_32 idat_size = png_ptr->idat_size;
622
623 /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
624 * are of different types and we don't know which variable has the fewest
625 * bits. Carefully select the smaller and cast it to the type of the
626 * larger - this cannot overflow.
627 */
628 if (idat_size < save_size)
629 save_size = (size_t)idat_size;
630
631 else
632 idat_size = (png_uint_32)save_size;
633
634 png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
635
636 png_process_IDAT_data(png_ptr, png_ptr->current_buffer_ptr, save_size);
637
638 png_ptr->idat_size -= idat_size;
639 png_ptr->buffer_size -= save_size;
640 png_ptr->current_buffer_size -= save_size;
641 png_ptr->current_buffer_ptr += save_size;
642 }
643
644 if (png_ptr->idat_size == 0)
645 {
646 PNG_PUSH_SAVE_BUFFER_IF_LT(4)
647 png_crc_finish(png_ptr, 0);
648 png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
649 png_ptr->mode |= PNG_AFTER_IDAT;
650 png_ptr->zowner = 0;
651 }
652 }
653
654 void /* PRIVATE */
655 png_process_IDAT_data(png_structrp png_ptr, png_bytep buffer,
656 size_t buffer_length)
657 {
658 /* The caller checks for a non-zero buffer length. */
659 if (!(buffer_length > 0) || buffer == NULL)
660 png_error(png_ptr, "No IDAT data (internal error)");
661
662 /* This routine must process all the data it has been given
663 * before returning, calling the row callback as required to
664 * handle the uncompressed results.
665 */
666 png_ptr->zstream.next_in = buffer;
667 /* TODO: WARNING: TRUNCATION ERROR: DANGER WILL ROBINSON: */
668 png_ptr->zstream.avail_in = (uInt)buffer_length;
669
670 /* Keep going until the decompressed data is all processed
671 * or the stream marked as finished.
672 */
673 while (png_ptr->zstream.avail_in > 0 &&
674 (png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED) == 0)
675 {
676 int ret;
677
678 /* We have data for zlib, but we must check that zlib
679 * has someplace to put the results. It doesn't matter
680 * if we don't expect any results -- it may be the input
681 * data is just the LZ end code.
682 */
683 if (!(png_ptr->zstream.avail_out > 0))
684 {
685 /* TODO: WARNING: TRUNCATION ERROR: DANGER WILL ROBINSON: */
686 png_ptr->zstream.avail_out = (uInt)(PNG_ROWBYTES(png_ptr->pixel_depth,
687 png_ptr->iwidth) + 1);
688
689 png_ptr->zstream.next_out = png_ptr->row_buf;
690 }
691
692 /* Using Z_SYNC_FLUSH here means that an unterminated
693 * LZ stream (a stream with a missing end code) can still
694 * be handled, otherwise (Z_NO_FLUSH) a future zlib
695 * implementation might defer output and therefore
696 * change the current behavior (see comments in inflate.c
697 * for why this doesn't happen at present with zlib 1.2.5).
698 */
699 ret = PNG_INFLATE(png_ptr, Z_SYNC_FLUSH);
700
701 /* Check for any failure before proceeding. */
702 if (ret != Z_OK && ret != Z_STREAM_END)
703 {
704 /* Terminate the decompression. */
705 png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
706 png_ptr->zowner = 0;
707
708 /* This may be a truncated stream (missing or
709 * damaged end code). Treat that as a warning.
710 */
711 if (png_ptr->row_number >= png_ptr->num_rows ||
712 png_ptr->pass > 6)
713 png_warning(png_ptr, "Truncated compressed data in IDAT");
714
715 else
716 {
717 if (ret == Z_DATA_ERROR)
718 png_benign_error(png_ptr, "IDAT: ADLER32 checksum mismatch");
719 else
720 png_error(png_ptr, "Decompression error in IDAT");
721 }
722
723 /* Skip the check on unprocessed input */
724 return;
725 }
726
727 /* Did inflate output any data? */
728 if (png_ptr->zstream.next_out != png_ptr->row_buf)
729 {
730 /* Is this unexpected data after the last row?
731 * If it is, artificially terminate the LZ output
732 * here.
733 */
734 if (png_ptr->row_number >= png_ptr->num_rows ||
735 png_ptr->pass > 6)
736 {
737 /* Extra data. */
738 png_warning(png_ptr, "Extra compressed data in IDAT");
739 png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
740 png_ptr->zowner = 0;
741
742 /* Do no more processing; skip the unprocessed
743 * input check below.
744 */
745 return;
746 }
747
748 /* Do we have a complete row? */
749 if (png_ptr->zstream.avail_out == 0)
750 png_push_process_row(png_ptr);
751 }
752
753 /* And check for the end of the stream. */
754 if (ret == Z_STREAM_END)
755 png_ptr->flags |= PNG_FLAG_ZSTREAM_ENDED;
756 }
757
758 /* All the data should have been processed, if anything
759 * is left at this point we have bytes of IDAT data
760 * after the zlib end code.
761 */
762 if (png_ptr->zstream.avail_in > 0)
763 png_warning(png_ptr, "Extra compression data in IDAT");
764 }
765
766 void /* PRIVATE */
767 png_push_process_row(png_structrp png_ptr)
768 {
769 /* 1.5.6: row_info moved out of png_struct to a local here. */
770 png_row_info row_info;
771
772 row_info.width = png_ptr->iwidth; /* NOTE: width of current interlaced row */
773 row_info.color_type = png_ptr->color_type;
774 row_info.bit_depth = png_ptr->bit_depth;
775 row_info.channels = png_ptr->channels;
776 row_info.pixel_depth = png_ptr->pixel_depth;
777 row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
778
779 if (png_ptr->row_buf[0] > PNG_FILTER_VALUE_NONE)
780 {
781 if (png_ptr->row_buf[0] < PNG_FILTER_VALUE_LAST)
782 png_read_filter_row(png_ptr, &row_info, png_ptr->row_buf + 1,
783 png_ptr->prev_row + 1, png_ptr->row_buf[0]);
784 else
785 png_error(png_ptr, "bad adaptive filter value");
786 }
787
788 /* libpng 1.5.6: the following line was copying png_ptr->rowbytes before
789 * 1.5.6, while the buffer really is this big in current versions of libpng
790 * it may not be in the future, so this was changed just to copy the
791 * interlaced row count:
792 */
793 memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1);
794
795 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
796 if (png_ptr->transformations != 0)
797 png_do_read_transformations(png_ptr, &row_info);
798 #endif
799
800 /* The transformed pixel depth should match the depth now in row_info. */
801 if (png_ptr->transformed_pixel_depth == 0)
802 {
803 png_ptr->transformed_pixel_depth = row_info.pixel_depth;
804 if (row_info.pixel_depth > png_ptr->maximum_pixel_depth)
805 png_error(png_ptr, "progressive row overflow");
806 }
807
808 else if (png_ptr->transformed_pixel_depth != row_info.pixel_depth)
809 png_error(png_ptr, "internal progressive row size calculation error");
810
811
812 #ifdef PNG_READ_INTERLACING_SUPPORTED
813 /* Expand interlaced rows to full size */
814 if (png_ptr->interlaced != 0 &&
815 (png_ptr->transformations & PNG_INTERLACE) != 0)
816 {
817 if (png_ptr->pass < 6)
818 png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass,
819 png_ptr->transformations);
820
821 switch (png_ptr->pass)
822 {
823 case 0:
824 {
825 int i;
826 for (i = 0; i < 8 && png_ptr->pass == 0; i++)
827 {
828 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
829 png_read_push_finish_row(png_ptr); /* Updates png_ptr->pass */
830 }
831
832 if (png_ptr->pass == 2) /* Pass 1 might be empty */
833 {
834 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
835 {
836 png_push_have_row(png_ptr, NULL);
837 png_read_push_finish_row(png_ptr);
838 }
839 }
840
841 if (png_ptr->pass == 4 && png_ptr->height <= 4)
842 {
843 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
844 {
845 png_push_have_row(png_ptr, NULL);
846 png_read_push_finish_row(png_ptr);
847 }
848 }
849
850 if (png_ptr->pass == 6 && png_ptr->height <= 4)
851 {
852 png_push_have_row(png_ptr, NULL);
853 png_read_push_finish_row(png_ptr);
854 }
855
856 break;
857 }
858
859 case 1:
860 {
861 int i;
862 for (i = 0; i < 8 && png_ptr->pass == 1; i++)
863 {
864 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
865 png_read_push_finish_row(png_ptr);
866 }
867
868 if (png_ptr->pass == 2) /* Skip top 4 generated rows */
869 {
870 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
871 {
872 png_push_have_row(png_ptr, NULL);
873 png_read_push_finish_row(png_ptr);
874 }
875 }
876
877 break;
878 }
879
880 case 2:
881 {
882 int i;
883
884 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
885 {
886 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
887 png_read_push_finish_row(png_ptr);
888 }
889
890 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
891 {
892 png_push_have_row(png_ptr, NULL);
893 png_read_push_finish_row(png_ptr);
894 }
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, NULL);
901 png_read_push_finish_row(png_ptr);
902 }
903 }
904
905 break;
906 }
907
908 case 3:
909 {
910 int i;
911
912 for (i = 0; i < 4 && png_ptr->pass == 3; i++)
913 {
914 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
915 png_read_push_finish_row(png_ptr);
916 }
917
918 if (png_ptr->pass == 4) /* Skip top two generated rows */
919 {
920 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
921 {
922 png_push_have_row(png_ptr, NULL);
923 png_read_push_finish_row(png_ptr);
924 }
925 }
926
927 break;
928 }
929
930 case 4:
931 {
932 int i;
933
934 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
935 {
936 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
937 png_read_push_finish_row(png_ptr);
938 }
939
940 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
941 {
942 png_push_have_row(png_ptr, NULL);
943 png_read_push_finish_row(png_ptr);
944 }
945
946 if (png_ptr->pass == 6) /* Pass 5 might be empty */
947 {
948 png_push_have_row(png_ptr, NULL);
949 png_read_push_finish_row(png_ptr);
950 }
951
952 break;
953 }
954
955 case 5:
956 {
957 int i;
958
959 for (i = 0; i < 2 && png_ptr->pass == 5; i++)
960 {
961 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
962 png_read_push_finish_row(png_ptr);
963 }
964
965 if (png_ptr->pass == 6) /* Skip top generated row */
966 {
967 png_push_have_row(png_ptr, NULL);
968 png_read_push_finish_row(png_ptr);
969 }
970
971 break;
972 }
973
974 default:
975 case 6:
976 {
977 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
978 png_read_push_finish_row(png_ptr);
979
980 if (png_ptr->pass != 6)
981 break;
982
983 png_push_have_row(png_ptr, NULL);
984 png_read_push_finish_row(png_ptr);
985 }
986 }
987 }
988 else
989 #endif
990 {
991 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
992 png_read_push_finish_row(png_ptr);
993 }
994 }
995
996 void /* PRIVATE */
997 png_read_push_finish_row(png_structrp png_ptr)
998 {
999 #ifdef PNG_READ_INTERLACING_SUPPORTED
1000 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
1001
1002 /* Start of interlace block */
1003 static PNG_CONST png_byte png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
1004
1005 /* Offset to next interlace block */
1006 static PNG_CONST png_byte png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
1007
1008 /* Start of interlace block in the y direction */
1009 static PNG_CONST png_byte png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
1010
1011 /* Offset to next interlace block in the y direction */
1012 static PNG_CONST png_byte png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
1013
1014 /* Height of interlace block. This is not currently used - if you need
1015 * it, uncomment it here and in png.h
1016 static PNG_CONST png_byte png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
1017 */
1018 #endif
1019
1020 png_ptr->row_number++;
1021 if (png_ptr->row_number < png_ptr->num_rows)
1022 return;
1023
1024 #ifdef PNG_READ_INTERLACING_SUPPORTED
1025 if (png_ptr->interlaced != 0)
1026 {
1027 png_ptr->row_number = 0;
1028 memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
1029
1030 do
1031 {
1032 png_ptr->pass++;
1033 if ((png_ptr->pass == 1 && png_ptr->width < 5) ||
1034 (png_ptr->pass == 3 && png_ptr->width < 3) ||
1035 (png_ptr->pass == 5 && png_ptr->width < 2))
1036 png_ptr->pass++;
1037
1038 if (png_ptr->pass > 7)
1039 png_ptr->pass--;
1040
1041 if (png_ptr->pass >= 7)
1042 break;
1043
1044 png_ptr->iwidth = (png_ptr->width +
1045 png_pass_inc[png_ptr->pass] - 1 -
1046 png_pass_start[png_ptr->pass]) /
1047 png_pass_inc[png_ptr->pass];
1048
1049 if ((png_ptr->transformations & PNG_INTERLACE) != 0)
1050 break;
1051
1052 png_ptr->num_rows = (png_ptr->height +
1053 png_pass_yinc[png_ptr->pass] - 1 -
1054 png_pass_ystart[png_ptr->pass]) /
1055 png_pass_yinc[png_ptr->pass];
1056
1057 } while (png_ptr->iwidth == 0 || png_ptr->num_rows == 0);
1058 }
1059 #endif /* READ_INTERLACING */
1060 }
1061
1062 void /* PRIVATE */
1063 png_push_have_info(png_structrp png_ptr, png_inforp info_ptr)
1064 {
1065 if (png_ptr->info_fn != NULL)
1066 (*(png_ptr->info_fn))(png_ptr, info_ptr);
1067 }
1068
1069 void /* PRIVATE */
1070 png_push_have_end(png_structrp png_ptr, png_inforp info_ptr)
1071 {
1072 if (png_ptr->end_fn != NULL)
1073 (*(png_ptr->end_fn))(png_ptr, info_ptr);
1074 }
1075
1076 void /* PRIVATE */
1077 png_push_have_row(png_structrp png_ptr, png_bytep row)
1078 {
1079 if (png_ptr->row_fn != NULL)
1080 (*(png_ptr->row_fn))(png_ptr, row, png_ptr->row_number,
1081 (int)png_ptr->pass);
1082 }
1083
1084 #ifdef PNG_READ_INTERLACING_SUPPORTED
1085 void PNGAPI
1086 png_progressive_combine_row(png_const_structrp png_ptr, png_bytep old_row,
1087 png_const_bytep new_row)
1088 {
1089 if (png_ptr == NULL)
1090 return;
1091
1092 /* new_row is a flag here - if it is NULL then the app callback was called
1093 * from an empty row (see the calls to png_struct::row_fn below), otherwise
1094 * it must be png_ptr->row_buf+1
1095 */
1096 if (new_row != NULL)
1097 png_combine_row(png_ptr, old_row, 1/*blocky display*/);
1098 }
1099 #endif /* READ_INTERLACING */
1100
1101 void PNGAPI
1102 png_set_progressive_read_fn(png_structrp png_ptr, png_voidp progressive_ptr,
1103 png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,
1104 png_progressive_end_ptr end_fn)
1105 {
1106 if (png_ptr == NULL)
1107 return;
1108
1109 png_ptr->info_fn = info_fn;
1110 png_ptr->row_fn = row_fn;
1111 png_ptr->end_fn = end_fn;
1112
1113 png_set_read_fn(png_ptr, progressive_ptr, png_push_fill_buffer);
1114 }
1115
1116 png_voidp PNGAPI
1117 png_get_progressive_ptr(png_const_structrp png_ptr)
1118 {
1119 if (png_ptr == NULL)
1120 return (NULL);
1121
1122 return png_ptr->io_ptr;
1123 }
1124 #endif /* PROGRESSIVE_READ */