2 /* pngpread.c - read a png file in push mode
4 * Last changed in libpng 1.6.15 [November 20, 2014]
5 * Copyright (c) 1998-2014 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.)
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
16 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
18 /* Push model modes */
19 #define PNG_READ_SIG_MODE 0
20 #define PNG_READ_CHUNK_MODE 1
21 #define PNG_READ_IDAT_MODE 2
22 #define PNG_SKIP_MODE 3
23 #define PNG_READ_tEXt_MODE 4
24 #define PNG_READ_zTXt_MODE 5
25 #define PNG_READ_DONE_MODE 6
26 #define PNG_READ_iTXt_MODE 7
27 #define PNG_ERROR_MODE 8
29 #define PNG_PUSH_SAVE_BUFFER_IF_FULL \
30 if (png_ptr->push_length + 4 > png_ptr->buffer_size) \
31 { png_push_save_buffer(png_ptr); return; }
32 #define PNG_PUSH_SAVE_BUFFER_IF_LT(N) \
33 if (png_ptr->buffer_size < N) \
34 { png_push_save_buffer(png_ptr); return; }
37 png_process_data(png_structrp png_ptr
, png_inforp info_ptr
,
38 png_bytep buffer
, png_size_t buffer_size
)
40 if (png_ptr
== NULL
|| info_ptr
== NULL
)
43 png_push_restore_buffer(png_ptr
, buffer
, buffer_size
);
45 while (png_ptr
->buffer_size
)
47 png_process_some_data(png_ptr
, info_ptr
);
52 png_process_data_pause(png_structrp png_ptr
, int save
)
56 /* It's easiest for the caller if we do the save; then the caller doesn't
57 * have to supply the same data again:
60 png_push_save_buffer(png_ptr
);
63 /* This includes any pending saved bytes: */
64 png_size_t remaining
= png_ptr
->buffer_size
;
65 png_ptr
->buffer_size
= 0;
67 /* So subtract the saved buffer size, unless all the data
68 * is actually 'saved', in which case we just return 0
70 if (png_ptr
->save_buffer_size
< remaining
)
71 return remaining
- png_ptr
->save_buffer_size
;
79 png_process_data_skip(png_structrp png_ptr
)
81 png_uint_32 remaining
= 0;
83 if (png_ptr
!= NULL
&& png_ptr
->process_mode
== PNG_SKIP_MODE
&&
84 png_ptr
->skip_length
> 0)
86 /* At the end of png_process_data the buffer size must be 0 (see the loop
87 * above) so we can detect a broken call here:
89 if (png_ptr
->buffer_size
!= 0)
91 "png_process_data_skip called inside png_process_data");
93 /* If is impossible for there to be a saved buffer at this point -
94 * otherwise we could not be in SKIP mode. This will also happen if
95 * png_process_skip is called inside png_process_data (but only very
98 if (png_ptr
->save_buffer_size
!= 0)
99 png_error(png_ptr
, "png_process_data_skip called with saved data");
101 remaining
= png_ptr
->skip_length
;
102 png_ptr
->skip_length
= 0;
103 png_ptr
->process_mode
= PNG_READ_CHUNK_MODE
;
109 /* What we do with the incoming data depends on what we were previously
110 * doing before we ran out of data...
113 png_process_some_data(png_structrp png_ptr
, png_inforp info_ptr
)
118 switch (png_ptr
->process_mode
)
120 case PNG_READ_SIG_MODE
:
122 png_push_read_sig(png_ptr
, info_ptr
);
126 case PNG_READ_CHUNK_MODE
:
128 png_push_read_chunk(png_ptr
, info_ptr
);
132 case PNG_READ_IDAT_MODE
:
134 png_push_read_IDAT(png_ptr
);
140 png_push_crc_finish(png_ptr
);
146 png_ptr
->buffer_size
= 0;
152 /* Read any remaining signature bytes from the stream and compare them with
153 * the correct PNG signature. It is possible that this routine is called
154 * with bytes already read from the signature, either because they have been
155 * checked by the calling application, or because of multiple calls to this
159 png_push_read_sig(png_structrp png_ptr
, png_inforp info_ptr
)
161 png_size_t num_checked
= png_ptr
->sig_bytes
, /* SAFE, does not exceed 8 */
162 num_to_check
= 8 - num_checked
;
164 if (png_ptr
->buffer_size
< num_to_check
)
166 num_to_check
= png_ptr
->buffer_size
;
169 png_push_fill_buffer(png_ptr
, &(info_ptr
->signature
[num_checked
]),
171 png_ptr
->sig_bytes
= (png_byte
)(png_ptr
->sig_bytes
+ num_to_check
);
173 if (png_sig_cmp(info_ptr
->signature
, num_checked
, num_to_check
))
175 if (num_checked
< 4 &&
176 png_sig_cmp(info_ptr
->signature
, num_checked
, num_to_check
- 4))
177 png_error(png_ptr
, "Not a PNG file");
180 png_error(png_ptr
, "PNG file corrupted by ASCII conversion");
184 if (png_ptr
->sig_bytes
>= 8)
186 png_ptr
->process_mode
= PNG_READ_CHUNK_MODE
;
192 png_push_read_chunk(png_structrp png_ptr
, png_inforp info_ptr
)
194 png_uint_32 chunk_name
;
195 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
196 int keep
; /* unknown handling method */
199 /* First we make sure we have enough data for the 4-byte chunk name
200 * and the 4-byte chunk length before proceeding with decoding the
201 * chunk data. To fully decode each of these chunks, we also make
202 * sure we have enough data in the buffer for the 4-byte CRC at the
203 * end of every chunk (except IDAT, which is handled separately).
205 if ((png_ptr
->mode
& PNG_HAVE_CHUNK_HEADER
) == 0)
207 png_byte chunk_length
[4];
208 png_byte chunk_tag
[4];
210 PNG_PUSH_SAVE_BUFFER_IF_LT(8)
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
, chunk_tag
, 4);
215 png_ptr
->chunk_name
= PNG_CHUNK_FROM_STRING(chunk_tag
);
216 png_check_chunk_name(png_ptr
, png_ptr
->chunk_name
);
217 png_ptr
->mode
|= PNG_HAVE_CHUNK_HEADER
;
220 chunk_name
= png_ptr
->chunk_name
;
222 #ifdef PNG_READ_APNG_SUPPORTED
223 if (png_ptr
->num_frames_read
> 0 &&
224 png_ptr
->num_frames_read
< info_ptr
->num_frames
)
226 if (chunk_name
== png_IDAT
)
228 /* Discard trailing IDATs for the first frame */
229 if ((png_ptr
->mode
& PNG_HAVE_fcTL
) != 0 ||
230 png_ptr
->num_frames_read
> 1)
231 png_error(png_ptr
, "out of place IDAT");
233 PNG_PUSH_SAVE_BUFFER_IF_FULL
234 png_push_crc_skip(png_ptr
, png_ptr
->push_length
);
235 png_ptr
->mode
&= ~PNG_HAVE_CHUNK_HEADER
;
238 else if (chunk_name
== png_fdAT
)
240 PNG_PUSH_SAVE_BUFFER_IF_LT(4)
241 png_ensure_sequence_number(png_ptr
, 4);
243 if ((png_ptr
->mode
& PNG_HAVE_fcTL
) == 0)
245 /* Discard trailing fdATs for frames other than the first */
246 if (png_ptr
->num_frames_read
< 2)
247 png_error(png_ptr
, "out of place fdAT");
249 PNG_PUSH_SAVE_BUFFER_IF_FULL
250 png_push_crc_skip(png_ptr
, png_ptr
->push_length
);
251 png_ptr
->mode
&= ~PNG_HAVE_CHUNK_HEADER
;
257 /* frame data follows */
258 png_ptr
->idat_size
= png_ptr
->push_length
- 4;
259 png_ptr
->mode
|= PNG_HAVE_IDAT
;
260 png_ptr
->process_mode
= PNG_READ_IDAT_MODE
;
266 else if (chunk_name
== png_fcTL
)
268 PNG_PUSH_SAVE_BUFFER_IF_FULL
269 png_read_reset(png_ptr
);
270 png_ptr
->mode
&= ~PNG_HAVE_fcTL
;
272 png_handle_fcTL(png_ptr
, info_ptr
, png_ptr
->push_length
);
274 if ((png_ptr
->mode
& PNG_HAVE_fcTL
) == 0)
275 png_error(png_ptr
, "missing required fcTL chunk");
277 png_read_reinit(png_ptr
, info_ptr
);
278 png_progressive_read_reset(png_ptr
);
280 if (png_ptr
->frame_info_fn
!= NULL
)
281 (*(png_ptr
->frame_info_fn
))(png_ptr
, png_ptr
->num_frames_read
);
283 png_ptr
->mode
&= ~PNG_HAVE_CHUNK_HEADER
;
290 PNG_PUSH_SAVE_BUFFER_IF_FULL
291 png_warning(png_ptr
, "Skipped (ignored) a chunk "
292 "between APNG chunks");
293 png_push_crc_skip(png_ptr
, png_ptr
->push_length
);
294 png_ptr
->mode
&= ~PNG_HAVE_CHUNK_HEADER
;
300 #endif /* READ_APNG */
302 if (chunk_name
== png_IDAT
)
304 if ((png_ptr
->mode
& PNG_AFTER_IDAT
) != 0)
305 png_ptr
->mode
|= PNG_HAVE_CHUNK_AFTER_IDAT
;
307 /* If we reach an IDAT chunk, this means we have read all of the
308 * header chunks, and we can start reading the image (or if this
309 * is called after the image has been read - we have an error).
311 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
312 png_error(png_ptr
, "Missing IHDR before IDAT");
314 else if (png_ptr
->color_type
== PNG_COLOR_TYPE_PALETTE
&&
315 (png_ptr
->mode
& PNG_HAVE_PLTE
) == 0)
316 png_error(png_ptr
, "Missing PLTE before IDAT");
318 png_ptr
->mode
|= PNG_HAVE_IDAT
;
319 png_ptr
->process_mode
= PNG_READ_IDAT_MODE
;
321 if ((png_ptr
->mode
& PNG_HAVE_CHUNK_AFTER_IDAT
) == 0)
322 if (png_ptr
->push_length
== 0)
325 if ((png_ptr
->mode
& PNG_AFTER_IDAT
) != 0)
326 png_benign_error(png_ptr
, "Too many IDATs found");
329 if (chunk_name
== png_IHDR
)
331 if (png_ptr
->push_length
!= 13)
332 png_error(png_ptr
, "Invalid IHDR length");
334 PNG_PUSH_SAVE_BUFFER_IF_FULL
335 png_handle_IHDR(png_ptr
, info_ptr
, png_ptr
->push_length
);
338 else if (chunk_name
== png_IEND
)
340 PNG_PUSH_SAVE_BUFFER_IF_FULL
341 png_handle_IEND(png_ptr
, info_ptr
, png_ptr
->push_length
);
343 png_ptr
->process_mode
= PNG_READ_DONE_MODE
;
344 png_push_have_end(png_ptr
, info_ptr
);
347 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
348 else if ((keep
= png_chunk_unknown_handling(png_ptr
, chunk_name
)) != 0)
350 PNG_PUSH_SAVE_BUFFER_IF_FULL
351 png_handle_unknown(png_ptr
, info_ptr
, png_ptr
->push_length
, keep
);
353 if (chunk_name
== png_PLTE
)
354 png_ptr
->mode
|= PNG_HAVE_PLTE
;
358 else if (chunk_name
== png_PLTE
)
360 PNG_PUSH_SAVE_BUFFER_IF_FULL
361 png_handle_PLTE(png_ptr
, info_ptr
, png_ptr
->push_length
);
364 else if (chunk_name
== png_IDAT
)
366 #ifdef PNG_READ_APNG_SUPPORTED
367 png_have_info(png_ptr
, info_ptr
);
369 png_ptr
->idat_size
= png_ptr
->push_length
;
370 png_ptr
->process_mode
= PNG_READ_IDAT_MODE
;
371 png_push_have_info(png_ptr
, info_ptr
);
372 png_ptr
->zstream
.avail_out
=
373 (uInt
) PNG_ROWBYTES(png_ptr
->pixel_depth
,
374 png_ptr
->iwidth
) + 1;
375 png_ptr
->zstream
.next_out
= png_ptr
->row_buf
;
379 #ifdef PNG_READ_gAMA_SUPPORTED
380 else if (png_ptr
->chunk_name
== png_gAMA
)
382 PNG_PUSH_SAVE_BUFFER_IF_FULL
383 png_handle_gAMA(png_ptr
, info_ptr
, png_ptr
->push_length
);
387 #ifdef PNG_READ_sBIT_SUPPORTED
388 else if (png_ptr
->chunk_name
== png_sBIT
)
390 PNG_PUSH_SAVE_BUFFER_IF_FULL
391 png_handle_sBIT(png_ptr
, info_ptr
, png_ptr
->push_length
);
395 #ifdef PNG_READ_cHRM_SUPPORTED
396 else if (png_ptr
->chunk_name
== png_cHRM
)
398 PNG_PUSH_SAVE_BUFFER_IF_FULL
399 png_handle_cHRM(png_ptr
, info_ptr
, png_ptr
->push_length
);
403 #ifdef PNG_READ_sRGB_SUPPORTED
404 else if (chunk_name
== png_sRGB
)
406 PNG_PUSH_SAVE_BUFFER_IF_FULL
407 png_handle_sRGB(png_ptr
, info_ptr
, png_ptr
->push_length
);
411 #ifdef PNG_READ_iCCP_SUPPORTED
412 else if (png_ptr
->chunk_name
== png_iCCP
)
414 PNG_PUSH_SAVE_BUFFER_IF_FULL
415 png_handle_iCCP(png_ptr
, info_ptr
, png_ptr
->push_length
);
419 #ifdef PNG_READ_sPLT_SUPPORTED
420 else if (chunk_name
== png_sPLT
)
422 PNG_PUSH_SAVE_BUFFER_IF_FULL
423 png_handle_sPLT(png_ptr
, info_ptr
, png_ptr
->push_length
);
427 #ifdef PNG_READ_tRNS_SUPPORTED
428 else if (chunk_name
== png_tRNS
)
430 PNG_PUSH_SAVE_BUFFER_IF_FULL
431 png_handle_tRNS(png_ptr
, info_ptr
, png_ptr
->push_length
);
435 #ifdef PNG_READ_bKGD_SUPPORTED
436 else if (chunk_name
== png_bKGD
)
438 PNG_PUSH_SAVE_BUFFER_IF_FULL
439 png_handle_bKGD(png_ptr
, info_ptr
, png_ptr
->push_length
);
443 #ifdef PNG_READ_hIST_SUPPORTED
444 else if (chunk_name
== png_hIST
)
446 PNG_PUSH_SAVE_BUFFER_IF_FULL
447 png_handle_hIST(png_ptr
, info_ptr
, png_ptr
->push_length
);
451 #ifdef PNG_READ_pHYs_SUPPORTED
452 else if (chunk_name
== png_pHYs
)
454 PNG_PUSH_SAVE_BUFFER_IF_FULL
455 png_handle_pHYs(png_ptr
, info_ptr
, png_ptr
->push_length
);
459 #ifdef PNG_READ_oFFs_SUPPORTED
460 else if (chunk_name
== png_oFFs
)
462 PNG_PUSH_SAVE_BUFFER_IF_FULL
463 png_handle_oFFs(png_ptr
, info_ptr
, png_ptr
->push_length
);
467 #ifdef PNG_READ_pCAL_SUPPORTED
468 else if (chunk_name
== png_pCAL
)
470 PNG_PUSH_SAVE_BUFFER_IF_FULL
471 png_handle_pCAL(png_ptr
, info_ptr
, png_ptr
->push_length
);
475 #ifdef PNG_READ_sCAL_SUPPORTED
476 else if (chunk_name
== png_sCAL
)
478 PNG_PUSH_SAVE_BUFFER_IF_FULL
479 png_handle_sCAL(png_ptr
, info_ptr
, png_ptr
->push_length
);
483 #ifdef PNG_READ_tIME_SUPPORTED
484 else if (chunk_name
== png_tIME
)
486 PNG_PUSH_SAVE_BUFFER_IF_FULL
487 png_handle_tIME(png_ptr
, info_ptr
, png_ptr
->push_length
);
491 #ifdef PNG_READ_tEXt_SUPPORTED
492 else if (chunk_name
== png_tEXt
)
494 PNG_PUSH_SAVE_BUFFER_IF_FULL
495 png_handle_tEXt(png_ptr
, info_ptr
, png_ptr
->push_length
);
499 #ifdef PNG_READ_zTXt_SUPPORTED
500 else if (chunk_name
== png_zTXt
)
502 PNG_PUSH_SAVE_BUFFER_IF_FULL
503 png_handle_zTXt(png_ptr
, info_ptr
, png_ptr
->push_length
);
507 #ifdef PNG_READ_iTXt_SUPPORTED
508 else if (chunk_name
== png_iTXt
)
510 PNG_PUSH_SAVE_BUFFER_IF_FULL
511 png_handle_iTXt(png_ptr
, info_ptr
, png_ptr
->push_length
);
515 #ifdef PNG_READ_APNG_SUPPORTED
516 else if (chunk_name
== png_acTL
)
518 PNG_PUSH_SAVE_BUFFER_IF_FULL
519 png_handle_acTL(png_ptr
, info_ptr
, png_ptr
->push_length
);
522 else if (chunk_name
== png_fcTL
)
524 PNG_PUSH_SAVE_BUFFER_IF_FULL
525 png_handle_fcTL(png_ptr
, info_ptr
, png_ptr
->push_length
);
528 #endif /* READ_APNG */
531 PNG_PUSH_SAVE_BUFFER_IF_FULL
532 png_handle_unknown(png_ptr
, info_ptr
, png_ptr
->push_length
,
533 PNG_HANDLE_CHUNK_AS_DEFAULT
);
536 png_ptr
->mode
&= ~PNG_HAVE_CHUNK_HEADER
;
540 png_push_crc_skip(png_structrp png_ptr
, png_uint_32 skip
)
542 png_ptr
->process_mode
= PNG_SKIP_MODE
;
543 png_ptr
->skip_length
= skip
;
547 png_push_crc_finish(png_structrp png_ptr
)
549 if (png_ptr
->skip_length
!= 0 && png_ptr
->save_buffer_size
!= 0)
551 png_size_t save_size
= png_ptr
->save_buffer_size
;
552 png_uint_32 skip_length
= png_ptr
->skip_length
;
554 /* We want the smaller of 'skip_length' and 'save_buffer_size', but
555 * they are of different types and we don't know which variable has the
556 * fewest bits. Carefully select the smaller and cast it to the type of
557 * the larger - this cannot overflow. Do not cast in the following test
558 * - it will break on either 16 or 64 bit platforms.
560 if (skip_length
< save_size
)
561 save_size
= (png_size_t
)skip_length
;
564 skip_length
= (png_uint_32
)save_size
;
566 png_calculate_crc(png_ptr
, png_ptr
->save_buffer_ptr
, save_size
);
568 png_ptr
->skip_length
-= skip_length
;
569 png_ptr
->buffer_size
-= save_size
;
570 png_ptr
->save_buffer_size
-= save_size
;
571 png_ptr
->save_buffer_ptr
+= save_size
;
573 if (png_ptr
->skip_length
!= 0 && png_ptr
->current_buffer_size
!= 0)
575 png_size_t save_size
= png_ptr
->current_buffer_size
;
576 png_uint_32 skip_length
= png_ptr
->skip_length
;
578 /* We want the smaller of 'skip_length' and 'current_buffer_size', here,
579 * the same problem exists as above and the same solution.
581 if (skip_length
< save_size
)
582 save_size
= (png_size_t
)skip_length
;
585 skip_length
= (png_uint_32
)save_size
;
587 png_calculate_crc(png_ptr
, png_ptr
->current_buffer_ptr
, save_size
);
589 png_ptr
->skip_length
-= skip_length
;
590 png_ptr
->buffer_size
-= save_size
;
591 png_ptr
->current_buffer_size
-= save_size
;
592 png_ptr
->current_buffer_ptr
+= save_size
;
594 if (png_ptr
->skip_length
== 0)
596 PNG_PUSH_SAVE_BUFFER_IF_LT(4)
597 png_crc_finish(png_ptr
, 0);
598 png_ptr
->process_mode
= PNG_READ_CHUNK_MODE
;
603 png_push_fill_buffer(png_structp png_ptr
, png_bytep buffer
, png_size_t length
)
611 if (png_ptr
->save_buffer_size
!= 0)
613 png_size_t save_size
;
615 if (length
< png_ptr
->save_buffer_size
)
619 save_size
= png_ptr
->save_buffer_size
;
621 memcpy(ptr
, png_ptr
->save_buffer_ptr
, save_size
);
624 png_ptr
->buffer_size
-= save_size
;
625 png_ptr
->save_buffer_size
-= save_size
;
626 png_ptr
->save_buffer_ptr
+= save_size
;
628 if (length
!= 0 && png_ptr
->current_buffer_size
!= 0)
630 png_size_t save_size
;
632 if (length
< png_ptr
->current_buffer_size
)
636 save_size
= png_ptr
->current_buffer_size
;
638 memcpy(ptr
, png_ptr
->current_buffer_ptr
, save_size
);
639 png_ptr
->buffer_size
-= save_size
;
640 png_ptr
->current_buffer_size
-= save_size
;
641 png_ptr
->current_buffer_ptr
+= save_size
;
646 png_push_save_buffer(png_structrp png_ptr
)
648 if (png_ptr
->save_buffer_size
!= 0)
650 if (png_ptr
->save_buffer_ptr
!= png_ptr
->save_buffer
)
656 istop
= png_ptr
->save_buffer_size
;
657 for (i
= 0, sp
= png_ptr
->save_buffer_ptr
, dp
= png_ptr
->save_buffer
;
658 i
< istop
; i
++, sp
++, dp
++)
664 if (png_ptr
->save_buffer_size
+ png_ptr
->current_buffer_size
>
665 png_ptr
->save_buffer_max
)
668 png_bytep old_buffer
;
670 if (png_ptr
->save_buffer_size
> PNG_SIZE_MAX
-
671 (png_ptr
->current_buffer_size
+ 256))
673 png_error(png_ptr
, "Potential overflow of save_buffer");
676 new_max
= png_ptr
->save_buffer_size
+ png_ptr
->current_buffer_size
+ 256;
677 old_buffer
= png_ptr
->save_buffer
;
678 png_ptr
->save_buffer
= (png_bytep
)png_malloc_warn(png_ptr
,
679 (png_size_t
)new_max
);
681 if (png_ptr
->save_buffer
== NULL
)
683 png_free(png_ptr
, old_buffer
);
685 png_error(png_ptr
, "Insufficient memory for save_buffer");
688 memcpy(png_ptr
->save_buffer
, old_buffer
, png_ptr
->save_buffer_size
);
689 png_free(png_ptr
, old_buffer
);
691 png_ptr
->save_buffer_max
= new_max
;
693 if (png_ptr
->current_buffer_size
)
695 memcpy(png_ptr
->save_buffer
+ png_ptr
->save_buffer_size
,
696 png_ptr
->current_buffer_ptr
, png_ptr
->current_buffer_size
);
697 png_ptr
->save_buffer_size
+= png_ptr
->current_buffer_size
;
698 png_ptr
->current_buffer_size
= 0;
700 png_ptr
->save_buffer_ptr
= png_ptr
->save_buffer
;
701 png_ptr
->buffer_size
= 0;
705 png_push_restore_buffer(png_structrp png_ptr
, png_bytep buffer
,
706 png_size_t buffer_length
)
708 png_ptr
->current_buffer
= buffer
;
709 png_ptr
->current_buffer_size
= buffer_length
;
710 png_ptr
->buffer_size
= buffer_length
+ png_ptr
->save_buffer_size
;
711 png_ptr
->current_buffer_ptr
= png_ptr
->current_buffer
;
715 png_push_read_IDAT(png_structrp png_ptr
)
717 if ((png_ptr
->mode
& PNG_HAVE_CHUNK_HEADER
) == 0)
719 png_byte chunk_length
[4];
720 png_byte chunk_tag
[4];
722 /* TODO: this code can be commoned up with the same code in push_read */
723 #ifdef PNG_READ_APNG_SUPPORTED
724 PNG_PUSH_SAVE_BUFFER_IF_LT(12)
726 PNG_PUSH_SAVE_BUFFER_IF_LT(8)
728 png_push_fill_buffer(png_ptr
, chunk_length
, 4);
729 png_ptr
->push_length
= png_get_uint_31(png_ptr
, chunk_length
);
730 png_reset_crc(png_ptr
);
731 png_crc_read(png_ptr
, chunk_tag
, 4);
732 png_ptr
->chunk_name
= PNG_CHUNK_FROM_STRING(chunk_tag
);
733 png_ptr
->mode
|= PNG_HAVE_CHUNK_HEADER
;
735 #ifdef PNG_READ_APNG_SUPPORTED
736 if (png_ptr
->chunk_name
!= png_fdAT
&& png_ptr
->num_frames_read
> 0)
738 if ((png_ptr
->flags
& PNG_FLAG_ZSTREAM_ENDED
) != 0)
740 png_ptr
->process_mode
= PNG_READ_CHUNK_MODE
;
741 if (png_ptr
->frame_end_fn
!= NULL
)
742 (*(png_ptr
->frame_end_fn
))(png_ptr
, png_ptr
->num_frames_read
);
743 png_ptr
->num_frames_read
++;
748 if (png_ptr
->chunk_name
== png_IEND
)
749 png_error(png_ptr
, "Not enough image data");
750 PNG_PUSH_SAVE_BUFFER_IF_FULL
751 png_warning(png_ptr
, "Skipping (ignoring) a chunk between "
753 png_crc_finish(png_ptr
, png_ptr
->push_length
);
754 png_ptr
->mode
&= ~PNG_HAVE_CHUNK_HEADER
;
760 #ifdef PNG_READ_APNG_SUPPORTED
761 if (png_ptr
->chunk_name
!= png_IDAT
&& png_ptr
->num_frames_read
== 0)
763 if (png_ptr
->chunk_name
!= png_IDAT
)
766 png_ptr
->process_mode
= PNG_READ_CHUNK_MODE
;
768 if ((png_ptr
->flags
& PNG_FLAG_ZSTREAM_ENDED
) == 0)
769 png_error(png_ptr
, "Not enough compressed data");
771 #ifdef PNG_READ_APNG_SUPPORTED
772 if (png_ptr
->frame_end_fn
!= NULL
)
773 (*(png_ptr
->frame_end_fn
))(png_ptr
, png_ptr
->num_frames_read
);
774 png_ptr
->num_frames_read
++;
780 png_ptr
->idat_size
= png_ptr
->push_length
;
782 #ifdef PNG_READ_APNG_SUPPORTED
783 if (png_ptr
->num_frames_read
> 0)
785 png_ensure_sequence_number(png_ptr
, 4);
786 png_ptr
->idat_size
-= 4;
791 if (png_ptr
->idat_size
!= 0 && png_ptr
->save_buffer_size
!= 0)
793 png_size_t save_size
= png_ptr
->save_buffer_size
;
794 png_uint_32 idat_size
= png_ptr
->idat_size
;
796 /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
797 * are of different types and we don't know which variable has the fewest
798 * bits. Carefully select the smaller and cast it to the type of the
799 * larger - this cannot overflow. Do not cast in the following test - it
800 * will break on either 16 or 64 bit platforms.
802 if (idat_size
< save_size
)
803 save_size
= (png_size_t
)idat_size
;
806 idat_size
= (png_uint_32
)save_size
;
808 png_calculate_crc(png_ptr
, png_ptr
->save_buffer_ptr
, save_size
);
810 png_process_IDAT_data(png_ptr
, png_ptr
->save_buffer_ptr
, save_size
);
812 png_ptr
->idat_size
-= idat_size
;
813 png_ptr
->buffer_size
-= save_size
;
814 png_ptr
->save_buffer_size
-= save_size
;
815 png_ptr
->save_buffer_ptr
+= save_size
;
818 if (png_ptr
->idat_size
!= 0 && png_ptr
->current_buffer_size
!= 0)
820 png_size_t save_size
= png_ptr
->current_buffer_size
;
821 png_uint_32 idat_size
= png_ptr
->idat_size
;
823 /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
824 * are of different types and we don't know which variable has the fewest
825 * bits. Carefully select the smaller and cast it to the type of the
826 * larger - this cannot overflow.
828 if (idat_size
< save_size
)
829 save_size
= (png_size_t
)idat_size
;
832 idat_size
= (png_uint_32
)save_size
;
834 png_calculate_crc(png_ptr
, png_ptr
->current_buffer_ptr
, save_size
);
836 png_process_IDAT_data(png_ptr
, png_ptr
->current_buffer_ptr
, save_size
);
838 png_ptr
->idat_size
-= idat_size
;
839 png_ptr
->buffer_size
-= save_size
;
840 png_ptr
->current_buffer_size
-= save_size
;
841 png_ptr
->current_buffer_ptr
+= save_size
;
843 if (png_ptr
->idat_size
== 0)
845 PNG_PUSH_SAVE_BUFFER_IF_LT(4)
846 png_crc_finish(png_ptr
, 0);
847 png_ptr
->mode
&= ~PNG_HAVE_CHUNK_HEADER
;
848 png_ptr
->mode
|= PNG_AFTER_IDAT
;
854 png_process_IDAT_data(png_structrp png_ptr
, png_bytep buffer
,
855 png_size_t buffer_length
)
857 /* The caller checks for a non-zero buffer length. */
858 if (!(buffer_length
> 0) || buffer
== NULL
)
859 png_error(png_ptr
, "No IDAT data (internal error)");
861 #ifdef PNG_READ_APNG_SUPPORTED
862 /* If the app is not APNG-aware, decode only the first frame */
863 if ((png_ptr
->apng_flags
& PNG_APNG_APP
) == 0 &&
864 png_ptr
->num_frames_read
> 0)
866 png_ptr
->flags
|= PNG_FLAG_ZSTREAM_ENDED
;
871 /* This routine must process all the data it has been given
872 * before returning, calling the row callback as required to
873 * handle the uncompressed results.
875 png_ptr
->zstream
.next_in
= buffer
;
876 /* TODO: WARNING: TRUNCATION ERROR: DANGER WILL ROBINSON: */
877 png_ptr
->zstream
.avail_in
= (uInt
)buffer_length
;
879 /* Keep going until the decompressed data is all processed
880 * or the stream marked as finished.
882 while (png_ptr
->zstream
.avail_in
> 0 &&
883 !(png_ptr
->flags
& PNG_FLAG_ZSTREAM_ENDED
))
887 /* We have data for zlib, but we must check that zlib
888 * has someplace to put the results. It doesn't matter
889 * if we don't expect any results -- it may be the input
890 * data is just the LZ end code.
892 if (!(png_ptr
->zstream
.avail_out
> 0))
894 /* TODO: WARNING: TRUNCATION ERROR: DANGER WILL ROBINSON: */
895 png_ptr
->zstream
.avail_out
= (uInt
)(PNG_ROWBYTES(png_ptr
->pixel_depth
,
896 png_ptr
->iwidth
) + 1);
898 png_ptr
->zstream
.next_out
= png_ptr
->row_buf
;
901 /* Using Z_SYNC_FLUSH here means that an unterminated
902 * LZ stream (a stream with a missing end code) can still
903 * be handled, otherwise (Z_NO_FLUSH) a future zlib
904 * implementation might defer output and therefore
905 * change the current behavior (see comments in inflate.c
906 * for why this doesn't happen at present with zlib 1.2.5).
908 ret
= inflate(&png_ptr
->zstream
, Z_SYNC_FLUSH
);
910 /* Check for any failure before proceeding. */
911 if (ret
!= Z_OK
&& ret
!= Z_STREAM_END
)
913 /* Terminate the decompression. */
914 png_ptr
->flags
|= PNG_FLAG_ZSTREAM_ENDED
;
917 /* This may be a truncated stream (missing or
918 * damaged end code). Treat that as a warning.
920 if (png_ptr
->row_number
>= png_ptr
->num_rows
||
922 png_warning(png_ptr
, "Truncated compressed data in IDAT");
925 png_error(png_ptr
, "Decompression error in IDAT");
927 /* Skip the check on unprocessed input */
931 /* Did inflate output any data? */
932 if (png_ptr
->zstream
.next_out
!= png_ptr
->row_buf
)
934 /* Is this unexpected data after the last row?
935 * If it is, artificially terminate the LZ output
938 if (png_ptr
->row_number
>= png_ptr
->num_rows
||
942 png_warning(png_ptr
, "Extra compressed data in IDAT");
943 png_ptr
->flags
|= PNG_FLAG_ZSTREAM_ENDED
;
946 /* Do no more processing; skip the unprocessed
952 /* Do we have a complete row? */
953 if (png_ptr
->zstream
.avail_out
== 0)
954 png_push_process_row(png_ptr
);
957 /* And check for the end of the stream. */
958 if (ret
== Z_STREAM_END
)
959 png_ptr
->flags
|= PNG_FLAG_ZSTREAM_ENDED
;
962 /* All the data should have been processed, if anything
963 * is left at this point we have bytes of IDAT data
964 * after the zlib end code.
966 if (png_ptr
->zstream
.avail_in
> 0)
967 png_warning(png_ptr
, "Extra compression data in IDAT");
971 png_push_process_row(png_structrp png_ptr
)
973 /* 1.5.6: row_info moved out of png_struct to a local here. */
974 png_row_info row_info
;
976 row_info
.width
= png_ptr
->iwidth
; /* NOTE: width of current interlaced row */
977 row_info
.color_type
= png_ptr
->color_type
;
978 row_info
.bit_depth
= png_ptr
->bit_depth
;
979 row_info
.channels
= png_ptr
->channels
;
980 row_info
.pixel_depth
= png_ptr
->pixel_depth
;
981 row_info
.rowbytes
= PNG_ROWBYTES(row_info
.pixel_depth
, row_info
.width
);
983 if (png_ptr
->row_buf
[0] > PNG_FILTER_VALUE_NONE
)
985 if (png_ptr
->row_buf
[0] < PNG_FILTER_VALUE_LAST
)
986 png_read_filter_row(png_ptr
, &row_info
, png_ptr
->row_buf
+ 1,
987 png_ptr
->prev_row
+ 1, png_ptr
->row_buf
[0]);
989 png_error(png_ptr
, "bad adaptive filter value");
992 /* libpng 1.5.6: the following line was copying png_ptr->rowbytes before
993 * 1.5.6, while the buffer really is this big in current versions of libpng
994 * it may not be in the future, so this was changed just to copy the
995 * interlaced row count:
997 memcpy(png_ptr
->prev_row
, png_ptr
->row_buf
, row_info
.rowbytes
+ 1);
999 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
1000 if (png_ptr
->transformations
!= 0)
1001 png_do_read_transformations(png_ptr
, &row_info
);
1004 /* The transformed pixel depth should match the depth now in row_info. */
1005 if (png_ptr
->transformed_pixel_depth
== 0)
1007 png_ptr
->transformed_pixel_depth
= row_info
.pixel_depth
;
1008 if (row_info
.pixel_depth
> png_ptr
->maximum_pixel_depth
)
1009 png_error(png_ptr
, "progressive row overflow");
1012 else if (png_ptr
->transformed_pixel_depth
!= row_info
.pixel_depth
)
1013 png_error(png_ptr
, "internal progressive row size calculation error");
1016 #ifdef PNG_READ_INTERLACING_SUPPORTED
1017 /* Expand interlaced rows to full size */
1018 if (png_ptr
->interlaced
!= 0 &&
1019 (png_ptr
->transformations
& PNG_INTERLACE
) != 0)
1021 if (png_ptr
->pass
< 6)
1022 png_do_read_interlace(&row_info
, png_ptr
->row_buf
+ 1, png_ptr
->pass
,
1023 png_ptr
->transformations
);
1025 switch (png_ptr
->pass
)
1030 for (i
= 0; i
< 8 && png_ptr
->pass
== 0; i
++)
1032 png_push_have_row(png_ptr
, png_ptr
->row_buf
+ 1);
1033 png_read_push_finish_row(png_ptr
); /* Updates png_ptr->pass */
1036 if (png_ptr
->pass
== 2) /* Pass 1 might be empty */
1038 for (i
= 0; i
< 4 && png_ptr
->pass
== 2; i
++)
1040 png_push_have_row(png_ptr
, NULL
);
1041 png_read_push_finish_row(png_ptr
);
1045 if (png_ptr
->pass
== 4 && png_ptr
->height
<= 4)
1047 for (i
= 0; i
< 2 && png_ptr
->pass
== 4; i
++)
1049 png_push_have_row(png_ptr
, NULL
);
1050 png_read_push_finish_row(png_ptr
);
1054 if (png_ptr
->pass
== 6 && png_ptr
->height
<= 4)
1056 png_push_have_row(png_ptr
, NULL
);
1057 png_read_push_finish_row(png_ptr
);
1066 for (i
= 0; i
< 8 && png_ptr
->pass
== 1; i
++)
1068 png_push_have_row(png_ptr
, png_ptr
->row_buf
+ 1);
1069 png_read_push_finish_row(png_ptr
);
1072 if (png_ptr
->pass
== 2) /* Skip top 4 generated rows */
1074 for (i
= 0; i
< 4 && png_ptr
->pass
== 2; i
++)
1076 png_push_have_row(png_ptr
, NULL
);
1077 png_read_push_finish_row(png_ptr
);
1088 for (i
= 0; i
< 4 && png_ptr
->pass
== 2; i
++)
1090 png_push_have_row(png_ptr
, png_ptr
->row_buf
+ 1);
1091 png_read_push_finish_row(png_ptr
);
1094 for (i
= 0; i
< 4 && png_ptr
->pass
== 2; i
++)
1096 png_push_have_row(png_ptr
, NULL
);
1097 png_read_push_finish_row(png_ptr
);
1100 if (png_ptr
->pass
== 4) /* Pass 3 might be empty */
1102 for (i
= 0; i
< 2 && png_ptr
->pass
== 4; i
++)
1104 png_push_have_row(png_ptr
, NULL
);
1105 png_read_push_finish_row(png_ptr
);
1116 for (i
= 0; i
< 4 && png_ptr
->pass
== 3; i
++)
1118 png_push_have_row(png_ptr
, png_ptr
->row_buf
+ 1);
1119 png_read_push_finish_row(png_ptr
);
1122 if (png_ptr
->pass
== 4) /* Skip top two generated rows */
1124 for (i
= 0; i
< 2 && png_ptr
->pass
== 4; i
++)
1126 png_push_have_row(png_ptr
, NULL
);
1127 png_read_push_finish_row(png_ptr
);
1138 for (i
= 0; i
< 2 && png_ptr
->pass
== 4; i
++)
1140 png_push_have_row(png_ptr
, png_ptr
->row_buf
+ 1);
1141 png_read_push_finish_row(png_ptr
);
1144 for (i
= 0; i
< 2 && png_ptr
->pass
== 4; i
++)
1146 png_push_have_row(png_ptr
, NULL
);
1147 png_read_push_finish_row(png_ptr
);
1150 if (png_ptr
->pass
== 6) /* Pass 5 might be empty */
1152 png_push_have_row(png_ptr
, NULL
);
1153 png_read_push_finish_row(png_ptr
);
1163 for (i
= 0; i
< 2 && png_ptr
->pass
== 5; i
++)
1165 png_push_have_row(png_ptr
, png_ptr
->row_buf
+ 1);
1166 png_read_push_finish_row(png_ptr
);
1169 if (png_ptr
->pass
== 6) /* Skip top generated row */
1171 png_push_have_row(png_ptr
, NULL
);
1172 png_read_push_finish_row(png_ptr
);
1181 png_push_have_row(png_ptr
, png_ptr
->row_buf
+ 1);
1182 png_read_push_finish_row(png_ptr
);
1184 if (png_ptr
->pass
!= 6)
1187 png_push_have_row(png_ptr
, NULL
);
1188 png_read_push_finish_row(png_ptr
);
1194 png_push_have_row(png_ptr
, png_ptr
->row_buf
+ 1);
1195 png_read_push_finish_row(png_ptr
);
1200 png_read_push_finish_row(png_structrp png_ptr
)
1202 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
1204 /* Start of interlace block */
1205 static PNG_CONST png_byte png_pass_start
[] = {0, 4, 0, 2, 0, 1, 0};
1207 /* Offset to next interlace block */
1208 static PNG_CONST png_byte png_pass_inc
[] = {8, 8, 4, 4, 2, 2, 1};
1210 /* Start of interlace block in the y direction */
1211 static PNG_CONST png_byte png_pass_ystart
[] = {0, 0, 4, 0, 2, 0, 1};
1213 /* Offset to next interlace block in the y direction */
1214 static PNG_CONST png_byte png_pass_yinc
[] = {8, 8, 8, 4, 4, 2, 2};
1216 /* Height of interlace block. This is not currently used - if you need
1217 * it, uncomment it here and in png.h
1218 static PNG_CONST png_byte png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
1222 png_ptr
->row_number
++;
1223 if (png_ptr
->row_number
< png_ptr
->num_rows
)
1226 if (png_ptr
->interlaced
!= 0)
1228 png_ptr
->row_number
= 0;
1229 memset(png_ptr
->prev_row
, 0, png_ptr
->rowbytes
+ 1);
1234 if ((png_ptr
->pass
== 1 && png_ptr
->width
< 5) ||
1235 (png_ptr
->pass
== 3 && png_ptr
->width
< 3) ||
1236 (png_ptr
->pass
== 5 && png_ptr
->width
< 2))
1239 if (png_ptr
->pass
> 7)
1242 if (png_ptr
->pass
>= 7)
1245 png_ptr
->iwidth
= (png_ptr
->width
+
1246 png_pass_inc
[png_ptr
->pass
] - 1 -
1247 png_pass_start
[png_ptr
->pass
]) /
1248 png_pass_inc
[png_ptr
->pass
];
1250 if ((png_ptr
->transformations
& PNG_INTERLACE
) != 0)
1253 png_ptr
->num_rows
= (png_ptr
->height
+
1254 png_pass_yinc
[png_ptr
->pass
] - 1 -
1255 png_pass_ystart
[png_ptr
->pass
]) /
1256 png_pass_yinc
[png_ptr
->pass
];
1258 } while (png_ptr
->iwidth
== 0 || png_ptr
->num_rows
== 0);
1263 png_push_have_info(png_structrp png_ptr
, png_inforp info_ptr
)
1265 if (png_ptr
->info_fn
!= NULL
)
1266 (*(png_ptr
->info_fn
))(png_ptr
, info_ptr
);
1270 png_push_have_end(png_structrp png_ptr
, png_inforp info_ptr
)
1272 if (png_ptr
->end_fn
!= NULL
)
1273 (*(png_ptr
->end_fn
))(png_ptr
, info_ptr
);
1277 png_push_have_row(png_structrp png_ptr
, png_bytep row
)
1279 if (png_ptr
->row_fn
!= NULL
)
1280 (*(png_ptr
->row_fn
))(png_ptr
, row
, png_ptr
->row_number
,
1281 (int)png_ptr
->pass
);
1285 png_progressive_combine_row(png_const_structrp png_ptr
, png_bytep old_row
,
1286 png_const_bytep new_row
)
1288 if (png_ptr
== NULL
)
1291 /* new_row is a flag here - if it is NULL then the app callback was called
1292 * from an empty row (see the calls to png_struct::row_fn below), otherwise
1293 * it must be png_ptr->row_buf+1
1295 if (new_row
!= NULL
)
1296 png_combine_row(png_ptr
, old_row
, 1/*blocky display*/);
1300 png_set_progressive_read_fn(png_structrp png_ptr
, png_voidp progressive_ptr
,
1301 png_progressive_info_ptr info_fn
, png_progressive_row_ptr row_fn
,
1302 png_progressive_end_ptr end_fn
)
1304 if (png_ptr
== NULL
)
1307 png_ptr
->info_fn
= info_fn
;
1308 png_ptr
->row_fn
= row_fn
;
1309 png_ptr
->end_fn
= end_fn
;
1311 png_set_read_fn(png_ptr
, progressive_ptr
, png_push_fill_buffer
);
1314 #ifdef PNG_READ_APNG_SUPPORTED
1316 png_set_progressive_frame_fn(png_structp png_ptr
,
1317 png_progressive_frame_ptr frame_info_fn
,
1318 png_progressive_frame_ptr frame_end_fn
)
1320 png_ptr
->frame_info_fn
= frame_info_fn
;
1321 png_ptr
->frame_end_fn
= frame_end_fn
;
1322 png_ptr
->apng_flags
|= PNG_APNG_APP
;
1327 png_get_progressive_ptr(png_const_structrp png_ptr
)
1329 if (png_ptr
== NULL
)
1332 return png_ptr
->io_ptr
;
1334 #endif /* PROGRESSIVE_READ */