2 /* pngpread.c - read a png file in push mode
4 * Last changed in libpng 1.6.18 [July 23, 2015]
5 * Copyright (c) 1998-2002,2004,2006-2015 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.)
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_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
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; }
36 png_process_data(png_structrp png_ptr
, png_inforp info_ptr
,
37 png_bytep buffer
, png_size_t buffer_size
)
39 if (png_ptr
== NULL
|| info_ptr
== NULL
)
42 png_push_restore_buffer(png_ptr
, buffer
, buffer_size
);
44 while (png_ptr
->buffer_size
)
46 png_process_some_data(png_ptr
, info_ptr
);
51 png_process_data_pause(png_structrp png_ptr
, int save
)
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:
59 png_push_save_buffer(png_ptr
);
62 /* This includes any pending saved bytes: */
63 png_size_t remaining
= png_ptr
->buffer_size
;
64 png_ptr
->buffer_size
= 0;
66 /* So subtract the saved buffer size, unless all the data
67 * is actually 'saved', in which case we just return 0
69 if (png_ptr
->save_buffer_size
< remaining
)
70 return remaining
- png_ptr
->save_buffer_size
;
78 png_process_data_skip(png_structrp png_ptr
)
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.
85 png_app_warning(png_ptr
,
86 "png_process_data_skip is not implemented in any current version of libpng");
90 /* What we do with the incoming data depends on what we were previously
91 * doing before we ran out of data...
94 png_process_some_data(png_structrp png_ptr
, png_inforp info_ptr
)
99 switch (png_ptr
->process_mode
)
101 case PNG_READ_SIG_MODE
:
103 png_push_read_sig(png_ptr
, info_ptr
);
107 case PNG_READ_CHUNK_MODE
:
109 png_push_read_chunk(png_ptr
, info_ptr
);
113 case PNG_READ_IDAT_MODE
:
115 png_push_read_IDAT(png_ptr
);
121 png_ptr
->buffer_size
= 0;
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
134 png_push_read_sig(png_structrp png_ptr
, png_inforp info_ptr
)
136 png_size_t num_checked
= png_ptr
->sig_bytes
, /* SAFE, does not exceed 8 */
137 num_to_check
= 8 - num_checked
;
139 if (png_ptr
->buffer_size
< num_to_check
)
141 num_to_check
= png_ptr
->buffer_size
;
144 png_push_fill_buffer(png_ptr
, &(info_ptr
->signature
[num_checked
]),
146 png_ptr
->sig_bytes
= (png_byte
)(png_ptr
->sig_bytes
+ num_to_check
);
148 if (png_sig_cmp(info_ptr
->signature
, num_checked
, num_to_check
))
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");
155 png_error(png_ptr
, "PNG file corrupted by ASCII conversion");
159 if (png_ptr
->sig_bytes
>= 8)
161 png_ptr
->process_mode
= PNG_READ_CHUNK_MODE
;
167 png_push_read_chunk(png_structrp png_ptr
, png_inforp info_ptr
)
169 png_uint_32 chunk_name
;
170 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
171 int keep
; /* unknown handling method */
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).
180 if ((png_ptr
->mode
& PNG_HAVE_CHUNK_HEADER
) == 0)
182 png_byte chunk_length
[4];
183 png_byte chunk_tag
[4];
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
;
195 chunk_name
= png_ptr
->chunk_name
;
197 if (chunk_name
== png_IDAT
)
199 if ((png_ptr
->mode
& PNG_AFTER_IDAT
) != 0)
200 png_ptr
->mode
|= PNG_HAVE_CHUNK_AFTER_IDAT
;
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).
206 if ((png_ptr
->mode
& PNG_HAVE_IHDR
) == 0)
207 png_error(png_ptr
, "Missing IHDR before IDAT");
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");
213 png_ptr
->mode
|= PNG_HAVE_IDAT
;
214 png_ptr
->process_mode
= PNG_READ_IDAT_MODE
;
216 if ((png_ptr
->mode
& PNG_HAVE_CHUNK_AFTER_IDAT
) == 0)
217 if (png_ptr
->push_length
== 0)
220 if ((png_ptr
->mode
& PNG_AFTER_IDAT
) != 0)
221 png_benign_error(png_ptr
, "Too many IDATs found");
224 if (chunk_name
== png_IHDR
)
226 if (png_ptr
->push_length
!= 13)
227 png_error(png_ptr
, "Invalid IHDR length");
229 PNG_PUSH_SAVE_BUFFER_IF_FULL
230 png_handle_IHDR(png_ptr
, info_ptr
, png_ptr
->push_length
);
233 else if (chunk_name
== png_IEND
)
235 PNG_PUSH_SAVE_BUFFER_IF_FULL
236 png_handle_IEND(png_ptr
, info_ptr
, png_ptr
->push_length
);
238 png_ptr
->process_mode
= PNG_READ_DONE_MODE
;
239 png_push_have_end(png_ptr
, info_ptr
);
242 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
243 else if ((keep
= png_chunk_unknown_handling(png_ptr
, chunk_name
)) != 0)
245 PNG_PUSH_SAVE_BUFFER_IF_FULL
246 png_handle_unknown(png_ptr
, info_ptr
, png_ptr
->push_length
, keep
);
248 if (chunk_name
== png_PLTE
)
249 png_ptr
->mode
|= PNG_HAVE_PLTE
;
253 else if (chunk_name
== png_PLTE
)
255 PNG_PUSH_SAVE_BUFFER_IF_FULL
256 png_handle_PLTE(png_ptr
, info_ptr
, png_ptr
->push_length
);
259 else if (chunk_name
== png_IDAT
)
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
;
271 #ifdef PNG_READ_gAMA_SUPPORTED
272 else if (png_ptr
->chunk_name
== png_gAMA
)
274 PNG_PUSH_SAVE_BUFFER_IF_FULL
275 png_handle_gAMA(png_ptr
, info_ptr
, png_ptr
->push_length
);
279 #ifdef PNG_READ_sBIT_SUPPORTED
280 else if (png_ptr
->chunk_name
== png_sBIT
)
282 PNG_PUSH_SAVE_BUFFER_IF_FULL
283 png_handle_sBIT(png_ptr
, info_ptr
, png_ptr
->push_length
);
287 #ifdef PNG_READ_cHRM_SUPPORTED
288 else if (png_ptr
->chunk_name
== png_cHRM
)
290 PNG_PUSH_SAVE_BUFFER_IF_FULL
291 png_handle_cHRM(png_ptr
, info_ptr
, png_ptr
->push_length
);
295 #ifdef PNG_READ_sRGB_SUPPORTED
296 else if (chunk_name
== png_sRGB
)
298 PNG_PUSH_SAVE_BUFFER_IF_FULL
299 png_handle_sRGB(png_ptr
, info_ptr
, png_ptr
->push_length
);
303 #ifdef PNG_READ_iCCP_SUPPORTED
304 else if (png_ptr
->chunk_name
== png_iCCP
)
306 PNG_PUSH_SAVE_BUFFER_IF_FULL
307 png_handle_iCCP(png_ptr
, info_ptr
, png_ptr
->push_length
);
311 #ifdef PNG_READ_sPLT_SUPPORTED
312 else if (chunk_name
== png_sPLT
)
314 PNG_PUSH_SAVE_BUFFER_IF_FULL
315 png_handle_sPLT(png_ptr
, info_ptr
, png_ptr
->push_length
);
319 #ifdef PNG_READ_tRNS_SUPPORTED
320 else if (chunk_name
== png_tRNS
)
322 PNG_PUSH_SAVE_BUFFER_IF_FULL
323 png_handle_tRNS(png_ptr
, info_ptr
, png_ptr
->push_length
);
327 #ifdef PNG_READ_bKGD_SUPPORTED
328 else if (chunk_name
== png_bKGD
)
330 PNG_PUSH_SAVE_BUFFER_IF_FULL
331 png_handle_bKGD(png_ptr
, info_ptr
, png_ptr
->push_length
);
335 #ifdef PNG_READ_hIST_SUPPORTED
336 else if (chunk_name
== png_hIST
)
338 PNG_PUSH_SAVE_BUFFER_IF_FULL
339 png_handle_hIST(png_ptr
, info_ptr
, png_ptr
->push_length
);
343 #ifdef PNG_READ_pHYs_SUPPORTED
344 else if (chunk_name
== png_pHYs
)
346 PNG_PUSH_SAVE_BUFFER_IF_FULL
347 png_handle_pHYs(png_ptr
, info_ptr
, png_ptr
->push_length
);
351 #ifdef PNG_READ_oFFs_SUPPORTED
352 else if (chunk_name
== png_oFFs
)
354 PNG_PUSH_SAVE_BUFFER_IF_FULL
355 png_handle_oFFs(png_ptr
, info_ptr
, png_ptr
->push_length
);
359 #ifdef PNG_READ_pCAL_SUPPORTED
360 else if (chunk_name
== png_pCAL
)
362 PNG_PUSH_SAVE_BUFFER_IF_FULL
363 png_handle_pCAL(png_ptr
, info_ptr
, png_ptr
->push_length
);
367 #ifdef PNG_READ_sCAL_SUPPORTED
368 else if (chunk_name
== png_sCAL
)
370 PNG_PUSH_SAVE_BUFFER_IF_FULL
371 png_handle_sCAL(png_ptr
, info_ptr
, png_ptr
->push_length
);
375 #ifdef PNG_READ_tIME_SUPPORTED
376 else if (chunk_name
== png_tIME
)
378 PNG_PUSH_SAVE_BUFFER_IF_FULL
379 png_handle_tIME(png_ptr
, info_ptr
, png_ptr
->push_length
);
383 #ifdef PNG_READ_tEXt_SUPPORTED
384 else if (chunk_name
== png_tEXt
)
386 PNG_PUSH_SAVE_BUFFER_IF_FULL
387 png_handle_tEXt(png_ptr
, info_ptr
, png_ptr
->push_length
);
391 #ifdef PNG_READ_zTXt_SUPPORTED
392 else if (chunk_name
== png_zTXt
)
394 PNG_PUSH_SAVE_BUFFER_IF_FULL
395 png_handle_zTXt(png_ptr
, info_ptr
, png_ptr
->push_length
);
399 #ifdef PNG_READ_iTXt_SUPPORTED
400 else if (chunk_name
== png_iTXt
)
402 PNG_PUSH_SAVE_BUFFER_IF_FULL
403 png_handle_iTXt(png_ptr
, info_ptr
, png_ptr
->push_length
);
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
);
414 png_ptr
->mode
&= ~PNG_HAVE_CHUNK_HEADER
;
418 png_push_fill_buffer(png_structp png_ptr
, png_bytep buffer
, png_size_t length
)
426 if (png_ptr
->save_buffer_size
!= 0)
428 png_size_t save_size
;
430 if (length
< png_ptr
->save_buffer_size
)
434 save_size
= png_ptr
->save_buffer_size
;
436 memcpy(ptr
, png_ptr
->save_buffer_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
;
443 if (length
!= 0 && png_ptr
->current_buffer_size
!= 0)
445 png_size_t save_size
;
447 if (length
< png_ptr
->current_buffer_size
)
451 save_size
= png_ptr
->current_buffer_size
;
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
;
461 png_push_save_buffer(png_structrp png_ptr
)
463 if (png_ptr
->save_buffer_size
!= 0)
465 if (png_ptr
->save_buffer_ptr
!= png_ptr
->save_buffer
)
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
++)
479 if (png_ptr
->save_buffer_size
+ png_ptr
->current_buffer_size
>
480 png_ptr
->save_buffer_max
)
483 png_bytep old_buffer
;
485 if (png_ptr
->save_buffer_size
> PNG_SIZE_MAX
-
486 (png_ptr
->current_buffer_size
+ 256))
488 png_error(png_ptr
, "Potential overflow of save_buffer");
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
);
496 if (png_ptr
->save_buffer
== NULL
)
498 png_free(png_ptr
, old_buffer
);
499 png_error(png_ptr
, "Insufficient memory for save_buffer");
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
;
506 if (png_ptr
->current_buffer_size
)
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;
513 png_ptr
->save_buffer_ptr
= png_ptr
->save_buffer
;
514 png_ptr
->buffer_size
= 0;
518 png_push_restore_buffer(png_structrp png_ptr
, png_bytep buffer
,
519 png_size_t buffer_length
)
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
;
528 png_push_read_IDAT(png_structrp png_ptr
)
530 if ((png_ptr
->mode
& PNG_HAVE_CHUNK_HEADER
) == 0)
532 png_byte chunk_length
[4];
533 png_byte chunk_tag
[4];
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
;
544 if (png_ptr
->chunk_name
!= png_IDAT
)
546 png_ptr
->process_mode
= PNG_READ_CHUNK_MODE
;
548 if ((png_ptr
->flags
& PNG_FLAG_ZSTREAM_ENDED
) == 0)
549 png_error(png_ptr
, "Not enough compressed data");
554 png_ptr
->idat_size
= png_ptr
->push_length
;
557 if (png_ptr
->idat_size
!= 0 && png_ptr
->save_buffer_size
!= 0)
559 png_size_t save_size
= png_ptr
->save_buffer_size
;
560 png_uint_32 idat_size
= png_ptr
->idat_size
;
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.
568 if (idat_size
< save_size
)
569 save_size
= (png_size_t
)idat_size
;
572 idat_size
= (png_uint_32
)save_size
;
574 png_calculate_crc(png_ptr
, png_ptr
->save_buffer_ptr
, save_size
);
576 png_process_IDAT_data(png_ptr
, png_ptr
->save_buffer_ptr
, save_size
);
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
;
584 if (png_ptr
->idat_size
!= 0 && png_ptr
->current_buffer_size
!= 0)
586 png_size_t save_size
= png_ptr
->current_buffer_size
;
587 png_uint_32 idat_size
= png_ptr
->idat_size
;
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.
594 if (idat_size
< save_size
)
595 save_size
= (png_size_t
)idat_size
;
598 idat_size
= (png_uint_32
)save_size
;
600 png_calculate_crc(png_ptr
, png_ptr
->current_buffer_ptr
, save_size
);
602 png_process_IDAT_data(png_ptr
, png_ptr
->current_buffer_ptr
, save_size
);
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
;
610 if (png_ptr
->idat_size
== 0)
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
;
621 png_process_IDAT_data(png_structrp png_ptr
, png_bytep buffer
,
622 png_size_t buffer_length
)
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)");
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.
632 png_ptr
->zstream
.next_in
= buffer
;
633 /* TODO: WARNING: TRUNCATION ERROR: DANGER WILL ROBINSON: */
634 png_ptr
->zstream
.avail_in
= (uInt
)buffer_length
;
636 /* Keep going until the decompressed data is all processed
637 * or the stream marked as finished.
639 while (png_ptr
->zstream
.avail_in
> 0 &&
640 (png_ptr
->flags
& PNG_FLAG_ZSTREAM_ENDED
) == 0)
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.
649 if (!(png_ptr
->zstream
.avail_out
> 0))
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);
655 png_ptr
->zstream
.next_out
= png_ptr
->row_buf
;
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).
665 ret
= PNG_INFLATE(png_ptr
, Z_SYNC_FLUSH
);
667 /* Check for any failure before proceeding. */
668 if (ret
!= Z_OK
&& ret
!= Z_STREAM_END
)
670 /* Terminate the decompression. */
671 png_ptr
->flags
|= PNG_FLAG_ZSTREAM_ENDED
;
674 /* This may be a truncated stream (missing or
675 * damaged end code). Treat that as a warning.
677 if (png_ptr
->row_number
>= png_ptr
->num_rows
||
679 png_warning(png_ptr
, "Truncated compressed data in IDAT");
682 png_error(png_ptr
, "Decompression error in IDAT");
684 /* Skip the check on unprocessed input */
688 /* Did inflate output any data? */
689 if (png_ptr
->zstream
.next_out
!= png_ptr
->row_buf
)
691 /* Is this unexpected data after the last row?
692 * If it is, artificially terminate the LZ output
695 if (png_ptr
->row_number
>= png_ptr
->num_rows
||
699 png_warning(png_ptr
, "Extra compressed data in IDAT");
700 png_ptr
->flags
|= PNG_FLAG_ZSTREAM_ENDED
;
703 /* Do no more processing; skip the unprocessed
709 /* Do we have a complete row? */
710 if (png_ptr
->zstream
.avail_out
== 0)
711 png_push_process_row(png_ptr
);
714 /* And check for the end of the stream. */
715 if (ret
== Z_STREAM_END
)
716 png_ptr
->flags
|= PNG_FLAG_ZSTREAM_ENDED
;
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.
723 if (png_ptr
->zstream
.avail_in
> 0)
724 png_warning(png_ptr
, "Extra compression data in IDAT");
728 png_push_process_row(png_structrp png_ptr
)
730 /* 1.5.6: row_info moved out of png_struct to a local here. */
731 png_row_info row_info
;
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
);
740 if (png_ptr
->row_buf
[0] > PNG_FILTER_VALUE_NONE
)
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]);
746 png_error(png_ptr
, "bad adaptive filter value");
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:
754 memcpy(png_ptr
->prev_row
, png_ptr
->row_buf
, row_info
.rowbytes
+ 1);
756 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
757 if (png_ptr
->transformations
!= 0)
758 png_do_read_transformations(png_ptr
, &row_info
);
761 /* The transformed pixel depth should match the depth now in row_info. */
762 if (png_ptr
->transformed_pixel_depth
== 0)
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");
769 else if (png_ptr
->transformed_pixel_depth
!= row_info
.pixel_depth
)
770 png_error(png_ptr
, "internal progressive row size calculation error");
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)
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
);
782 switch (png_ptr
->pass
)
787 for (i
= 0; i
< 8 && png_ptr
->pass
== 0; i
++)
789 png_push_have_row(png_ptr
, png_ptr
->row_buf
+ 1);
790 png_read_push_finish_row(png_ptr
); /* Updates png_ptr->pass */
793 if (png_ptr
->pass
== 2) /* Pass 1 might be empty */
795 for (i
= 0; i
< 4 && png_ptr
->pass
== 2; i
++)
797 png_push_have_row(png_ptr
, NULL
);
798 png_read_push_finish_row(png_ptr
);
802 if (png_ptr
->pass
== 4 && png_ptr
->height
<= 4)
804 for (i
= 0; i
< 2 && png_ptr
->pass
== 4; i
++)
806 png_push_have_row(png_ptr
, NULL
);
807 png_read_push_finish_row(png_ptr
);
811 if (png_ptr
->pass
== 6 && png_ptr
->height
<= 4)
813 png_push_have_row(png_ptr
, NULL
);
814 png_read_push_finish_row(png_ptr
);
823 for (i
= 0; i
< 8 && png_ptr
->pass
== 1; i
++)
825 png_push_have_row(png_ptr
, png_ptr
->row_buf
+ 1);
826 png_read_push_finish_row(png_ptr
);
829 if (png_ptr
->pass
== 2) /* Skip top 4 generated rows */
831 for (i
= 0; i
< 4 && png_ptr
->pass
== 2; i
++)
833 png_push_have_row(png_ptr
, NULL
);
834 png_read_push_finish_row(png_ptr
);
845 for (i
= 0; i
< 4 && png_ptr
->pass
== 2; i
++)
847 png_push_have_row(png_ptr
, png_ptr
->row_buf
+ 1);
848 png_read_push_finish_row(png_ptr
);
851 for (i
= 0; i
< 4 && png_ptr
->pass
== 2; i
++)
853 png_push_have_row(png_ptr
, NULL
);
854 png_read_push_finish_row(png_ptr
);
857 if (png_ptr
->pass
== 4) /* Pass 3 might be empty */
859 for (i
= 0; i
< 2 && png_ptr
->pass
== 4; i
++)
861 png_push_have_row(png_ptr
, NULL
);
862 png_read_push_finish_row(png_ptr
);
873 for (i
= 0; i
< 4 && png_ptr
->pass
== 3; i
++)
875 png_push_have_row(png_ptr
, png_ptr
->row_buf
+ 1);
876 png_read_push_finish_row(png_ptr
);
879 if (png_ptr
->pass
== 4) /* Skip top two generated rows */
881 for (i
= 0; i
< 2 && png_ptr
->pass
== 4; i
++)
883 png_push_have_row(png_ptr
, NULL
);
884 png_read_push_finish_row(png_ptr
);
895 for (i
= 0; i
< 2 && png_ptr
->pass
== 4; i
++)
897 png_push_have_row(png_ptr
, png_ptr
->row_buf
+ 1);
898 png_read_push_finish_row(png_ptr
);
901 for (i
= 0; i
< 2 && png_ptr
->pass
== 4; i
++)
903 png_push_have_row(png_ptr
, NULL
);
904 png_read_push_finish_row(png_ptr
);
907 if (png_ptr
->pass
== 6) /* Pass 5 might be empty */
909 png_push_have_row(png_ptr
, NULL
);
910 png_read_push_finish_row(png_ptr
);
920 for (i
= 0; i
< 2 && png_ptr
->pass
== 5; i
++)
922 png_push_have_row(png_ptr
, png_ptr
->row_buf
+ 1);
923 png_read_push_finish_row(png_ptr
);
926 if (png_ptr
->pass
== 6) /* Skip top generated row */
928 png_push_have_row(png_ptr
, NULL
);
929 png_read_push_finish_row(png_ptr
);
938 png_push_have_row(png_ptr
, png_ptr
->row_buf
+ 1);
939 png_read_push_finish_row(png_ptr
);
941 if (png_ptr
->pass
!= 6)
944 png_push_have_row(png_ptr
, NULL
);
945 png_read_push_finish_row(png_ptr
);
952 png_push_have_row(png_ptr
, png_ptr
->row_buf
+ 1);
953 png_read_push_finish_row(png_ptr
);
958 png_read_push_finish_row(png_structrp png_ptr
)
960 #ifdef PNG_READ_INTERLACING_SUPPORTED
961 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
963 /* Start of interlace block */
964 static PNG_CONST png_byte png_pass_start
[] = {0, 4, 0, 2, 0, 1, 0};
966 /* Offset to next interlace block */
967 static PNG_CONST png_byte png_pass_inc
[] = {8, 8, 4, 4, 2, 2, 1};
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};
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};
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};
981 png_ptr
->row_number
++;
982 if (png_ptr
->row_number
< png_ptr
->num_rows
)
985 #ifdef PNG_READ_INTERLACING_SUPPORTED
986 if (png_ptr
->interlaced
!= 0)
988 png_ptr
->row_number
= 0;
989 memset(png_ptr
->prev_row
, 0, png_ptr
->rowbytes
+ 1);
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))
999 if (png_ptr
->pass
> 7)
1002 if (png_ptr
->pass
>= 7)
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
];
1010 if ((png_ptr
->transformations
& PNG_INTERLACE
) != 0)
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
];
1018 } while (png_ptr
->iwidth
== 0 || png_ptr
->num_rows
== 0);
1020 #endif /* READ_INTERLACING */
1024 png_push_have_info(png_structrp png_ptr
, png_inforp info_ptr
)
1026 if (png_ptr
->info_fn
!= NULL
)
1027 (*(png_ptr
->info_fn
))(png_ptr
, info_ptr
);
1031 png_push_have_end(png_structrp png_ptr
, png_inforp info_ptr
)
1033 if (png_ptr
->end_fn
!= NULL
)
1034 (*(png_ptr
->end_fn
))(png_ptr
, info_ptr
);
1038 png_push_have_row(png_structrp png_ptr
, png_bytep row
)
1040 if (png_ptr
->row_fn
!= NULL
)
1041 (*(png_ptr
->row_fn
))(png_ptr
, row
, png_ptr
->row_number
,
1042 (int)png_ptr
->pass
);
1045 #ifdef PNG_READ_INTERLACING_SUPPORTED
1047 png_progressive_combine_row(png_const_structrp png_ptr
, png_bytep old_row
,
1048 png_const_bytep new_row
)
1050 if (png_ptr
== NULL
)
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
1057 if (new_row
!= NULL
)
1058 png_combine_row(png_ptr
, old_row
, 1/*blocky display*/);
1060 #endif /* READ_INTERLACING */
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
)
1067 if (png_ptr
== NULL
)
1070 png_ptr
->info_fn
= info_fn
;
1071 png_ptr
->row_fn
= row_fn
;
1072 png_ptr
->end_fn
= end_fn
;
1074 png_set_read_fn(png_ptr
, progressive_ptr
, png_push_fill_buffer
);
1078 png_get_progressive_ptr(png_const_structrp png_ptr
)
1080 if (png_ptr
== NULL
)
1083 return png_ptr
->io_ptr
;
1085 #endif /* PROGRESSIVE_READ */