2 /* pngpread.c - read a png file in push mode
4 * Last changed in libpng 1.6.24 [August 4, 2016]
5 * Copyright (c) 1998-2002,2004,2006-2016 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
->process_mode
= PNG_READ_IDAT_MODE
;
215 if ((png_ptr
->mode
& PNG_HAVE_IDAT
) != 0)
216 if ((png_ptr
->mode
& PNG_HAVE_CHUNK_AFTER_IDAT
) == 0)
217 if (png_ptr
->push_length
== 0)
220 png_ptr
->mode
|= PNG_HAVE_IDAT
;
222 if ((png_ptr
->mode
& PNG_AFTER_IDAT
) != 0)
223 png_benign_error(png_ptr
, "Too many IDATs found");
226 if (chunk_name
== png_IHDR
)
228 if (png_ptr
->push_length
!= 13)
229 png_error(png_ptr
, "Invalid IHDR length");
231 PNG_PUSH_SAVE_BUFFER_IF_FULL
232 png_handle_IHDR(png_ptr
, info_ptr
, png_ptr
->push_length
);
235 else if (chunk_name
== png_IEND
)
237 PNG_PUSH_SAVE_BUFFER_IF_FULL
238 png_handle_IEND(png_ptr
, info_ptr
, png_ptr
->push_length
);
240 png_ptr
->process_mode
= PNG_READ_DONE_MODE
;
241 png_push_have_end(png_ptr
, info_ptr
);
244 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
245 else if ((keep
= png_chunk_unknown_handling(png_ptr
, chunk_name
)) != 0)
247 PNG_PUSH_SAVE_BUFFER_IF_FULL
248 png_handle_unknown(png_ptr
, info_ptr
, png_ptr
->push_length
, keep
);
250 if (chunk_name
== png_PLTE
)
251 png_ptr
->mode
|= PNG_HAVE_PLTE
;
255 else if (chunk_name
== png_PLTE
)
257 PNG_PUSH_SAVE_BUFFER_IF_FULL
258 png_handle_PLTE(png_ptr
, info_ptr
, png_ptr
->push_length
);
261 else if (chunk_name
== png_IDAT
)
263 png_ptr
->idat_size
= png_ptr
->push_length
;
264 png_ptr
->process_mode
= PNG_READ_IDAT_MODE
;
265 png_push_have_info(png_ptr
, info_ptr
);
266 png_ptr
->zstream
.avail_out
=
267 (uInt
) PNG_ROWBYTES(png_ptr
->pixel_depth
,
268 png_ptr
->iwidth
) + 1;
269 png_ptr
->zstream
.next_out
= png_ptr
->row_buf
;
273 #ifdef PNG_READ_gAMA_SUPPORTED
274 else if (png_ptr
->chunk_name
== png_gAMA
)
276 PNG_PUSH_SAVE_BUFFER_IF_FULL
277 png_handle_gAMA(png_ptr
, info_ptr
, png_ptr
->push_length
);
281 #ifdef PNG_READ_sBIT_SUPPORTED
282 else if (png_ptr
->chunk_name
== png_sBIT
)
284 PNG_PUSH_SAVE_BUFFER_IF_FULL
285 png_handle_sBIT(png_ptr
, info_ptr
, png_ptr
->push_length
);
289 #ifdef PNG_READ_cHRM_SUPPORTED
290 else if (png_ptr
->chunk_name
== png_cHRM
)
292 PNG_PUSH_SAVE_BUFFER_IF_FULL
293 png_handle_cHRM(png_ptr
, info_ptr
, png_ptr
->push_length
);
297 #ifdef PNG_READ_sRGB_SUPPORTED
298 else if (chunk_name
== png_sRGB
)
300 PNG_PUSH_SAVE_BUFFER_IF_FULL
301 png_handle_sRGB(png_ptr
, info_ptr
, png_ptr
->push_length
);
305 #ifdef PNG_READ_iCCP_SUPPORTED
306 else if (png_ptr
->chunk_name
== png_iCCP
)
308 PNG_PUSH_SAVE_BUFFER_IF_FULL
309 png_handle_iCCP(png_ptr
, info_ptr
, png_ptr
->push_length
);
313 #ifdef PNG_READ_sPLT_SUPPORTED
314 else if (chunk_name
== png_sPLT
)
316 PNG_PUSH_SAVE_BUFFER_IF_FULL
317 png_handle_sPLT(png_ptr
, info_ptr
, png_ptr
->push_length
);
321 #ifdef PNG_READ_tRNS_SUPPORTED
322 else if (chunk_name
== png_tRNS
)
324 PNG_PUSH_SAVE_BUFFER_IF_FULL
325 png_handle_tRNS(png_ptr
, info_ptr
, png_ptr
->push_length
);
329 #ifdef PNG_READ_bKGD_SUPPORTED
330 else if (chunk_name
== png_bKGD
)
332 PNG_PUSH_SAVE_BUFFER_IF_FULL
333 png_handle_bKGD(png_ptr
, info_ptr
, png_ptr
->push_length
);
337 #ifdef PNG_READ_hIST_SUPPORTED
338 else if (chunk_name
== png_hIST
)
340 PNG_PUSH_SAVE_BUFFER_IF_FULL
341 png_handle_hIST(png_ptr
, info_ptr
, png_ptr
->push_length
);
345 #ifdef PNG_READ_pHYs_SUPPORTED
346 else if (chunk_name
== png_pHYs
)
348 PNG_PUSH_SAVE_BUFFER_IF_FULL
349 png_handle_pHYs(png_ptr
, info_ptr
, png_ptr
->push_length
);
353 #ifdef PNG_READ_oFFs_SUPPORTED
354 else if (chunk_name
== png_oFFs
)
356 PNG_PUSH_SAVE_BUFFER_IF_FULL
357 png_handle_oFFs(png_ptr
, info_ptr
, png_ptr
->push_length
);
361 #ifdef PNG_READ_pCAL_SUPPORTED
362 else if (chunk_name
== png_pCAL
)
364 PNG_PUSH_SAVE_BUFFER_IF_FULL
365 png_handle_pCAL(png_ptr
, info_ptr
, png_ptr
->push_length
);
369 #ifdef PNG_READ_sCAL_SUPPORTED
370 else if (chunk_name
== png_sCAL
)
372 PNG_PUSH_SAVE_BUFFER_IF_FULL
373 png_handle_sCAL(png_ptr
, info_ptr
, png_ptr
->push_length
);
377 #ifdef PNG_READ_tIME_SUPPORTED
378 else if (chunk_name
== png_tIME
)
380 PNG_PUSH_SAVE_BUFFER_IF_FULL
381 png_handle_tIME(png_ptr
, info_ptr
, png_ptr
->push_length
);
385 #ifdef PNG_READ_tEXt_SUPPORTED
386 else if (chunk_name
== png_tEXt
)
388 PNG_PUSH_SAVE_BUFFER_IF_FULL
389 png_handle_tEXt(png_ptr
, info_ptr
, png_ptr
->push_length
);
393 #ifdef PNG_READ_zTXt_SUPPORTED
394 else if (chunk_name
== png_zTXt
)
396 PNG_PUSH_SAVE_BUFFER_IF_FULL
397 png_handle_zTXt(png_ptr
, info_ptr
, png_ptr
->push_length
);
401 #ifdef PNG_READ_iTXt_SUPPORTED
402 else if (chunk_name
== png_iTXt
)
404 PNG_PUSH_SAVE_BUFFER_IF_FULL
405 png_handle_iTXt(png_ptr
, info_ptr
, png_ptr
->push_length
);
411 PNG_PUSH_SAVE_BUFFER_IF_FULL
412 png_handle_unknown(png_ptr
, info_ptr
, png_ptr
->push_length
,
413 PNG_HANDLE_CHUNK_AS_DEFAULT
);
416 png_ptr
->mode
&= ~PNG_HAVE_CHUNK_HEADER
;
420 png_push_fill_buffer(png_structp png_ptr
, png_bytep buffer
, png_size_t length
)
428 if (png_ptr
->save_buffer_size
!= 0)
430 png_size_t save_size
;
432 if (length
< png_ptr
->save_buffer_size
)
436 save_size
= png_ptr
->save_buffer_size
;
438 memcpy(ptr
, png_ptr
->save_buffer_ptr
, save_size
);
441 png_ptr
->buffer_size
-= save_size
;
442 png_ptr
->save_buffer_size
-= save_size
;
443 png_ptr
->save_buffer_ptr
+= save_size
;
445 if (length
!= 0 && png_ptr
->current_buffer_size
!= 0)
447 png_size_t save_size
;
449 if (length
< png_ptr
->current_buffer_size
)
453 save_size
= png_ptr
->current_buffer_size
;
455 memcpy(ptr
, png_ptr
->current_buffer_ptr
, save_size
);
456 png_ptr
->buffer_size
-= save_size
;
457 png_ptr
->current_buffer_size
-= save_size
;
458 png_ptr
->current_buffer_ptr
+= save_size
;
463 png_push_save_buffer(png_structrp png_ptr
)
465 if (png_ptr
->save_buffer_size
!= 0)
467 if (png_ptr
->save_buffer_ptr
!= png_ptr
->save_buffer
)
473 istop
= png_ptr
->save_buffer_size
;
474 for (i
= 0, sp
= png_ptr
->save_buffer_ptr
, dp
= png_ptr
->save_buffer
;
475 i
< istop
; i
++, sp
++, dp
++)
481 if (png_ptr
->save_buffer_size
+ png_ptr
->current_buffer_size
>
482 png_ptr
->save_buffer_max
)
485 png_bytep old_buffer
;
487 if (png_ptr
->save_buffer_size
> PNG_SIZE_MAX
-
488 (png_ptr
->current_buffer_size
+ 256))
490 png_error(png_ptr
, "Potential overflow of save_buffer");
493 new_max
= png_ptr
->save_buffer_size
+ png_ptr
->current_buffer_size
+ 256;
494 old_buffer
= png_ptr
->save_buffer
;
495 png_ptr
->save_buffer
= (png_bytep
)png_malloc_warn(png_ptr
,
496 (png_size_t
)new_max
);
498 if (png_ptr
->save_buffer
== NULL
)
500 png_free(png_ptr
, old_buffer
);
501 png_error(png_ptr
, "Insufficient memory for save_buffer");
505 memcpy(png_ptr
->save_buffer
, old_buffer
, png_ptr
->save_buffer_size
);
506 else if (png_ptr
->save_buffer_size
)
507 png_error(png_ptr
, "save_buffer error");
508 png_free(png_ptr
, old_buffer
);
509 png_ptr
->save_buffer_max
= new_max
;
511 if (png_ptr
->current_buffer_size
)
513 memcpy(png_ptr
->save_buffer
+ png_ptr
->save_buffer_size
,
514 png_ptr
->current_buffer_ptr
, png_ptr
->current_buffer_size
);
515 png_ptr
->save_buffer_size
+= png_ptr
->current_buffer_size
;
516 png_ptr
->current_buffer_size
= 0;
518 png_ptr
->save_buffer_ptr
= png_ptr
->save_buffer
;
519 png_ptr
->buffer_size
= 0;
523 png_push_restore_buffer(png_structrp png_ptr
, png_bytep buffer
,
524 png_size_t buffer_length
)
526 png_ptr
->current_buffer
= buffer
;
527 png_ptr
->current_buffer_size
= buffer_length
;
528 png_ptr
->buffer_size
= buffer_length
+ png_ptr
->save_buffer_size
;
529 png_ptr
->current_buffer_ptr
= png_ptr
->current_buffer
;
533 png_push_read_IDAT(png_structrp png_ptr
)
535 if ((png_ptr
->mode
& PNG_HAVE_CHUNK_HEADER
) == 0)
537 png_byte chunk_length
[4];
538 png_byte chunk_tag
[4];
540 /* TODO: this code can be commoned up with the same code in push_read */
541 PNG_PUSH_SAVE_BUFFER_IF_LT(8)
542 png_push_fill_buffer(png_ptr
, chunk_length
, 4);
543 png_ptr
->push_length
= png_get_uint_31(png_ptr
, chunk_length
);
544 png_reset_crc(png_ptr
);
545 png_crc_read(png_ptr
, chunk_tag
, 4);
546 png_ptr
->chunk_name
= PNG_CHUNK_FROM_STRING(chunk_tag
);
547 png_ptr
->mode
|= PNG_HAVE_CHUNK_HEADER
;
549 if (png_ptr
->chunk_name
!= png_IDAT
)
551 png_ptr
->process_mode
= PNG_READ_CHUNK_MODE
;
553 if ((png_ptr
->flags
& PNG_FLAG_ZSTREAM_ENDED
) == 0)
554 png_error(png_ptr
, "Not enough compressed data");
559 png_ptr
->idat_size
= png_ptr
->push_length
;
562 if (png_ptr
->idat_size
!= 0 && png_ptr
->save_buffer_size
!= 0)
564 png_size_t save_size
= png_ptr
->save_buffer_size
;
565 png_uint_32 idat_size
= png_ptr
->idat_size
;
567 /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
568 * are of different types and we don't know which variable has the fewest
569 * bits. Carefully select the smaller and cast it to the type of the
570 * larger - this cannot overflow. Do not cast in the following test - it
571 * will break on either 16-bit or 64-bit platforms.
573 if (idat_size
< save_size
)
574 save_size
= (png_size_t
)idat_size
;
577 idat_size
= (png_uint_32
)save_size
;
579 png_calculate_crc(png_ptr
, png_ptr
->save_buffer_ptr
, save_size
);
581 png_process_IDAT_data(png_ptr
, png_ptr
->save_buffer_ptr
, save_size
);
583 png_ptr
->idat_size
-= idat_size
;
584 png_ptr
->buffer_size
-= save_size
;
585 png_ptr
->save_buffer_size
-= save_size
;
586 png_ptr
->save_buffer_ptr
+= save_size
;
589 if (png_ptr
->idat_size
!= 0 && png_ptr
->current_buffer_size
!= 0)
591 png_size_t save_size
= png_ptr
->current_buffer_size
;
592 png_uint_32 idat_size
= png_ptr
->idat_size
;
594 /* We want the smaller of 'idat_size' and 'current_buffer_size', but they
595 * are of different types and we don't know which variable has the fewest
596 * bits. Carefully select the smaller and cast it to the type of the
597 * larger - this cannot overflow.
599 if (idat_size
< save_size
)
600 save_size
= (png_size_t
)idat_size
;
603 idat_size
= (png_uint_32
)save_size
;
605 png_calculate_crc(png_ptr
, png_ptr
->current_buffer_ptr
, save_size
);
607 png_process_IDAT_data(png_ptr
, png_ptr
->current_buffer_ptr
, save_size
);
609 png_ptr
->idat_size
-= idat_size
;
610 png_ptr
->buffer_size
-= save_size
;
611 png_ptr
->current_buffer_size
-= save_size
;
612 png_ptr
->current_buffer_ptr
+= save_size
;
615 if (png_ptr
->idat_size
== 0)
617 PNG_PUSH_SAVE_BUFFER_IF_LT(4)
618 png_crc_finish(png_ptr
, 0);
619 png_ptr
->mode
&= ~PNG_HAVE_CHUNK_HEADER
;
620 png_ptr
->mode
|= PNG_AFTER_IDAT
;
626 png_process_IDAT_data(png_structrp png_ptr
, png_bytep buffer
,
627 png_size_t buffer_length
)
629 /* The caller checks for a non-zero buffer length. */
630 if (!(buffer_length
> 0) || buffer
== NULL
)
631 png_error(png_ptr
, "No IDAT data (internal error)");
633 /* This routine must process all the data it has been given
634 * before returning, calling the row callback as required to
635 * handle the uncompressed results.
637 png_ptr
->zstream
.next_in
= buffer
;
638 /* TODO: WARNING: TRUNCATION ERROR: DANGER WILL ROBINSON: */
639 png_ptr
->zstream
.avail_in
= (uInt
)buffer_length
;
641 /* Keep going until the decompressed data is all processed
642 * or the stream marked as finished.
644 while (png_ptr
->zstream
.avail_in
> 0 &&
645 (png_ptr
->flags
& PNG_FLAG_ZSTREAM_ENDED
) == 0)
649 /* We have data for zlib, but we must check that zlib
650 * has someplace to put the results. It doesn't matter
651 * if we don't expect any results -- it may be the input
652 * data is just the LZ end code.
654 if (!(png_ptr
->zstream
.avail_out
> 0))
656 /* TODO: WARNING: TRUNCATION ERROR: DANGER WILL ROBINSON: */
657 png_ptr
->zstream
.avail_out
= (uInt
)(PNG_ROWBYTES(png_ptr
->pixel_depth
,
658 png_ptr
->iwidth
) + 1);
660 png_ptr
->zstream
.next_out
= png_ptr
->row_buf
;
663 /* Using Z_SYNC_FLUSH here means that an unterminated
664 * LZ stream (a stream with a missing end code) can still
665 * be handled, otherwise (Z_NO_FLUSH) a future zlib
666 * implementation might defer output and therefore
667 * change the current behavior (see comments in inflate.c
668 * for why this doesn't happen at present with zlib 1.2.5).
670 ret
= PNG_INFLATE(png_ptr
, Z_SYNC_FLUSH
);
672 /* Check for any failure before proceeding. */
673 if (ret
!= Z_OK
&& ret
!= Z_STREAM_END
)
675 /* Terminate the decompression. */
676 png_ptr
->flags
|= PNG_FLAG_ZSTREAM_ENDED
;
679 /* This may be a truncated stream (missing or
680 * damaged end code). Treat that as a warning.
682 if (png_ptr
->row_number
>= png_ptr
->num_rows
||
684 png_warning(png_ptr
, "Truncated compressed data in IDAT");
688 if (ret
== Z_DATA_ERROR
)
689 png_benign_error(png_ptr
, "IDAT: ADLER32 checksum mismatch");
691 png_error(png_ptr
, "Decompression error in IDAT");
694 /* Skip the check on unprocessed input */
698 /* Did inflate output any data? */
699 if (png_ptr
->zstream
.next_out
!= png_ptr
->row_buf
)
701 /* Is this unexpected data after the last row?
702 * If it is, artificially terminate the LZ output
705 if (png_ptr
->row_number
>= png_ptr
->num_rows
||
709 png_warning(png_ptr
, "Extra compressed data in IDAT");
710 png_ptr
->flags
|= PNG_FLAG_ZSTREAM_ENDED
;
713 /* Do no more processing; skip the unprocessed
719 /* Do we have a complete row? */
720 if (png_ptr
->zstream
.avail_out
== 0)
721 png_push_process_row(png_ptr
);
724 /* And check for the end of the stream. */
725 if (ret
== Z_STREAM_END
)
726 png_ptr
->flags
|= PNG_FLAG_ZSTREAM_ENDED
;
729 /* All the data should have been processed, if anything
730 * is left at this point we have bytes of IDAT data
731 * after the zlib end code.
733 if (png_ptr
->zstream
.avail_in
> 0)
734 png_warning(png_ptr
, "Extra compression data in IDAT");
738 png_push_process_row(png_structrp png_ptr
)
740 /* 1.5.6: row_info moved out of png_struct to a local here. */
741 png_row_info row_info
;
743 row_info
.width
= png_ptr
->iwidth
; /* NOTE: width of current interlaced row */
744 row_info
.color_type
= png_ptr
->color_type
;
745 row_info
.bit_depth
= png_ptr
->bit_depth
;
746 row_info
.channels
= png_ptr
->channels
;
747 row_info
.pixel_depth
= png_ptr
->pixel_depth
;
748 row_info
.rowbytes
= PNG_ROWBYTES(row_info
.pixel_depth
, row_info
.width
);
750 if (png_ptr
->row_buf
[0] > PNG_FILTER_VALUE_NONE
)
752 if (png_ptr
->row_buf
[0] < PNG_FILTER_VALUE_LAST
)
753 png_read_filter_row(png_ptr
, &row_info
, png_ptr
->row_buf
+ 1,
754 png_ptr
->prev_row
+ 1, png_ptr
->row_buf
[0]);
756 png_error(png_ptr
, "bad adaptive filter value");
759 /* libpng 1.5.6: the following line was copying png_ptr->rowbytes before
760 * 1.5.6, while the buffer really is this big in current versions of libpng
761 * it may not be in the future, so this was changed just to copy the
762 * interlaced row count:
764 memcpy(png_ptr
->prev_row
, png_ptr
->row_buf
, row_info
.rowbytes
+ 1);
766 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
767 if (png_ptr
->transformations
!= 0)
768 png_do_read_transformations(png_ptr
, &row_info
);
771 /* The transformed pixel depth should match the depth now in row_info. */
772 if (png_ptr
->transformed_pixel_depth
== 0)
774 png_ptr
->transformed_pixel_depth
= row_info
.pixel_depth
;
775 if (row_info
.pixel_depth
> png_ptr
->maximum_pixel_depth
)
776 png_error(png_ptr
, "progressive row overflow");
779 else if (png_ptr
->transformed_pixel_depth
!= row_info
.pixel_depth
)
780 png_error(png_ptr
, "internal progressive row size calculation error");
783 #ifdef PNG_READ_INTERLACING_SUPPORTED
784 /* Expand interlaced rows to full size */
785 if (png_ptr
->interlaced
!= 0 &&
786 (png_ptr
->transformations
& PNG_INTERLACE
) != 0)
788 if (png_ptr
->pass
< 6)
789 png_do_read_interlace(&row_info
, png_ptr
->row_buf
+ 1, png_ptr
->pass
,
790 png_ptr
->transformations
);
792 switch (png_ptr
->pass
)
797 for (i
= 0; i
< 8 && png_ptr
->pass
== 0; i
++)
799 png_push_have_row(png_ptr
, png_ptr
->row_buf
+ 1);
800 png_read_push_finish_row(png_ptr
); /* Updates png_ptr->pass */
803 if (png_ptr
->pass
== 2) /* Pass 1 might be empty */
805 for (i
= 0; i
< 4 && png_ptr
->pass
== 2; i
++)
807 png_push_have_row(png_ptr
, NULL
);
808 png_read_push_finish_row(png_ptr
);
812 if (png_ptr
->pass
== 4 && png_ptr
->height
<= 4)
814 for (i
= 0; i
< 2 && png_ptr
->pass
== 4; i
++)
816 png_push_have_row(png_ptr
, NULL
);
817 png_read_push_finish_row(png_ptr
);
821 if (png_ptr
->pass
== 6 && png_ptr
->height
<= 4)
823 png_push_have_row(png_ptr
, NULL
);
824 png_read_push_finish_row(png_ptr
);
833 for (i
= 0; i
< 8 && png_ptr
->pass
== 1; i
++)
835 png_push_have_row(png_ptr
, png_ptr
->row_buf
+ 1);
836 png_read_push_finish_row(png_ptr
);
839 if (png_ptr
->pass
== 2) /* Skip top 4 generated rows */
841 for (i
= 0; i
< 4 && png_ptr
->pass
== 2; i
++)
843 png_push_have_row(png_ptr
, NULL
);
844 png_read_push_finish_row(png_ptr
);
855 for (i
= 0; i
< 4 && png_ptr
->pass
== 2; i
++)
857 png_push_have_row(png_ptr
, png_ptr
->row_buf
+ 1);
858 png_read_push_finish_row(png_ptr
);
861 for (i
= 0; i
< 4 && png_ptr
->pass
== 2; i
++)
863 png_push_have_row(png_ptr
, NULL
);
864 png_read_push_finish_row(png_ptr
);
867 if (png_ptr
->pass
== 4) /* Pass 3 might be empty */
869 for (i
= 0; i
< 2 && png_ptr
->pass
== 4; i
++)
871 png_push_have_row(png_ptr
, NULL
);
872 png_read_push_finish_row(png_ptr
);
883 for (i
= 0; i
< 4 && png_ptr
->pass
== 3; i
++)
885 png_push_have_row(png_ptr
, png_ptr
->row_buf
+ 1);
886 png_read_push_finish_row(png_ptr
);
889 if (png_ptr
->pass
== 4) /* Skip top two generated rows */
891 for (i
= 0; i
< 2 && png_ptr
->pass
== 4; i
++)
893 png_push_have_row(png_ptr
, NULL
);
894 png_read_push_finish_row(png_ptr
);
905 for (i
= 0; i
< 2 && png_ptr
->pass
== 4; i
++)
907 png_push_have_row(png_ptr
, png_ptr
->row_buf
+ 1);
908 png_read_push_finish_row(png_ptr
);
911 for (i
= 0; i
< 2 && png_ptr
->pass
== 4; i
++)
913 png_push_have_row(png_ptr
, NULL
);
914 png_read_push_finish_row(png_ptr
);
917 if (png_ptr
->pass
== 6) /* Pass 5 might be empty */
919 png_push_have_row(png_ptr
, NULL
);
920 png_read_push_finish_row(png_ptr
);
930 for (i
= 0; i
< 2 && png_ptr
->pass
== 5; i
++)
932 png_push_have_row(png_ptr
, png_ptr
->row_buf
+ 1);
933 png_read_push_finish_row(png_ptr
);
936 if (png_ptr
->pass
== 6) /* Skip top generated row */
938 png_push_have_row(png_ptr
, NULL
);
939 png_read_push_finish_row(png_ptr
);
948 png_push_have_row(png_ptr
, png_ptr
->row_buf
+ 1);
949 png_read_push_finish_row(png_ptr
);
951 if (png_ptr
->pass
!= 6)
954 png_push_have_row(png_ptr
, NULL
);
955 png_read_push_finish_row(png_ptr
);
962 png_push_have_row(png_ptr
, png_ptr
->row_buf
+ 1);
963 png_read_push_finish_row(png_ptr
);
968 png_read_push_finish_row(png_structrp png_ptr
)
970 #ifdef PNG_READ_INTERLACING_SUPPORTED
971 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
973 /* Start of interlace block */
974 static PNG_CONST png_byte png_pass_start
[] = {0, 4, 0, 2, 0, 1, 0};
976 /* Offset to next interlace block */
977 static PNG_CONST png_byte png_pass_inc
[] = {8, 8, 4, 4, 2, 2, 1};
979 /* Start of interlace block in the y direction */
980 static PNG_CONST png_byte png_pass_ystart
[] = {0, 0, 4, 0, 2, 0, 1};
982 /* Offset to next interlace block in the y direction */
983 static PNG_CONST png_byte png_pass_yinc
[] = {8, 8, 8, 4, 4, 2, 2};
985 /* Height of interlace block. This is not currently used - if you need
986 * it, uncomment it here and in png.h
987 static PNG_CONST png_byte png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
991 png_ptr
->row_number
++;
992 if (png_ptr
->row_number
< png_ptr
->num_rows
)
995 #ifdef PNG_READ_INTERLACING_SUPPORTED
996 if (png_ptr
->interlaced
!= 0)
998 png_ptr
->row_number
= 0;
999 memset(png_ptr
->prev_row
, 0, png_ptr
->rowbytes
+ 1);
1004 if ((png_ptr
->pass
== 1 && png_ptr
->width
< 5) ||
1005 (png_ptr
->pass
== 3 && png_ptr
->width
< 3) ||
1006 (png_ptr
->pass
== 5 && png_ptr
->width
< 2))
1009 if (png_ptr
->pass
> 7)
1012 if (png_ptr
->pass
>= 7)
1015 png_ptr
->iwidth
= (png_ptr
->width
+
1016 png_pass_inc
[png_ptr
->pass
] - 1 -
1017 png_pass_start
[png_ptr
->pass
]) /
1018 png_pass_inc
[png_ptr
->pass
];
1020 if ((png_ptr
->transformations
& PNG_INTERLACE
) != 0)
1023 png_ptr
->num_rows
= (png_ptr
->height
+
1024 png_pass_yinc
[png_ptr
->pass
] - 1 -
1025 png_pass_ystart
[png_ptr
->pass
]) /
1026 png_pass_yinc
[png_ptr
->pass
];
1028 } while (png_ptr
->iwidth
== 0 || png_ptr
->num_rows
== 0);
1030 #endif /* READ_INTERLACING */
1034 png_push_have_info(png_structrp png_ptr
, png_inforp info_ptr
)
1036 if (png_ptr
->info_fn
!= NULL
)
1037 (*(png_ptr
->info_fn
))(png_ptr
, info_ptr
);
1041 png_push_have_end(png_structrp png_ptr
, png_inforp info_ptr
)
1043 if (png_ptr
->end_fn
!= NULL
)
1044 (*(png_ptr
->end_fn
))(png_ptr
, info_ptr
);
1048 png_push_have_row(png_structrp png_ptr
, png_bytep row
)
1050 if (png_ptr
->row_fn
!= NULL
)
1051 (*(png_ptr
->row_fn
))(png_ptr
, row
, png_ptr
->row_number
,
1052 (int)png_ptr
->pass
);
1055 #ifdef PNG_READ_INTERLACING_SUPPORTED
1057 png_progressive_combine_row(png_const_structrp png_ptr
, png_bytep old_row
,
1058 png_const_bytep new_row
)
1060 if (png_ptr
== NULL
)
1063 /* new_row is a flag here - if it is NULL then the app callback was called
1064 * from an empty row (see the calls to png_struct::row_fn below), otherwise
1065 * it must be png_ptr->row_buf+1
1067 if (new_row
!= NULL
)
1068 png_combine_row(png_ptr
, old_row
, 1/*blocky display*/);
1070 #endif /* READ_INTERLACING */
1073 png_set_progressive_read_fn(png_structrp png_ptr
, png_voidp progressive_ptr
,
1074 png_progressive_info_ptr info_fn
, png_progressive_row_ptr row_fn
,
1075 png_progressive_end_ptr end_fn
)
1077 if (png_ptr
== NULL
)
1080 png_ptr
->info_fn
= info_fn
;
1081 png_ptr
->row_fn
= row_fn
;
1082 png_ptr
->end_fn
= end_fn
;
1084 png_set_read_fn(png_ptr
, progressive_ptr
, png_push_fill_buffer
);
1088 png_get_progressive_ptr(png_const_structrp png_ptr
)
1090 if (png_ptr
== NULL
)
1093 return png_ptr
->io_ptr
;
1095 #endif /* PROGRESSIVE_READ */