2 /* pngpread.c - read a png file in push mode
4 * Last changed in libpng 1.4.0 [January 3, 2010]
5 * Copyright (c) 1998-2010 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
14 #define PNG_NO_PEDANTIC_WARNINGS
16 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
19 /* Push model modes */
20 #define PNG_READ_SIG_MODE 0
21 #define PNG_READ_CHUNK_MODE 1
22 #define PNG_READ_IDAT_MODE 2
23 #define PNG_SKIP_MODE 3
24 #define PNG_READ_tEXt_MODE 4
25 #define PNG_READ_zTXt_MODE 5
26 #define PNG_READ_DONE_MODE 6
27 #define PNG_READ_iTXt_MODE 7
28 #define PNG_ERROR_MODE 8
31 png_process_data(png_structp png_ptr, png_infop info_ptr,
32 png_bytep buffer, png_size_t buffer_size)
34 if (png_ptr == NULL || info_ptr == NULL)
37 png_push_restore_buffer(png_ptr, buffer, buffer_size);
39 while (png_ptr->buffer_size)
41 png_process_some_data(png_ptr, info_ptr);
45 /* What we do with the incoming data depends on what we were previously
46 * doing before we ran out of data...
49 png_process_some_data(png_structp png_ptr, png_infop info_ptr)
54 switch (png_ptr->process_mode)
56 case PNG_READ_SIG_MODE:
58 png_push_read_sig(png_ptr, info_ptr);
62 case PNG_READ_CHUNK_MODE:
64 png_push_read_chunk(png_ptr, info_ptr);
68 case PNG_READ_IDAT_MODE:
70 png_push_read_IDAT(png_ptr);
74 #ifdef PNG_READ_tEXt_SUPPORTED
75 case PNG_READ_tEXt_MODE:
77 png_push_read_tEXt(png_ptr, info_ptr);
82 #ifdef PNG_READ_zTXt_SUPPORTED
83 case PNG_READ_zTXt_MODE:
85 png_push_read_zTXt(png_ptr, info_ptr);
90 #ifdef PNG_READ_iTXt_SUPPORTED
91 case PNG_READ_iTXt_MODE:
93 png_push_read_iTXt(png_ptr, info_ptr);
100 png_push_crc_finish(png_ptr);
106 png_ptr->buffer_size = 0;
112 /* Read any remaining signature bytes from the stream and compare them with
113 * the correct PNG signature. It is possible that this routine is called
114 * with bytes already read from the signature, either because they have been
115 * checked by the calling application, or because of multiple calls to this
119 png_push_read_sig(png_structp png_ptr, png_infop info_ptr)
121 png_size_t num_checked = png_ptr->sig_bytes,
122 num_to_check = 8 - num_checked;
124 if (png_ptr->buffer_size < num_to_check)
126 num_to_check = png_ptr->buffer_size;
129 png_push_fill_buffer(png_ptr, &(info_ptr->signature[num_checked]),
131 png_ptr->sig_bytes = (png_byte)(png_ptr->sig_bytes + num_to_check);
133 if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
135 if (num_checked < 4 &&
136 png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
137 png_error(png_ptr, "Not a PNG file");
139 png_error(png_ptr, "PNG file corrupted by ASCII conversion");
143 if (png_ptr->sig_bytes >= 8)
145 png_ptr->process_mode = PNG_READ_CHUNK_MODE;
151 png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
157 #ifdef PNG_READ_bKGD_SUPPORTED
160 #ifdef PNG_READ_cHRM_SUPPORTED
163 #ifdef PNG_READ_gAMA_SUPPORTED
166 #ifdef PNG_READ_hIST_SUPPORTED
169 #ifdef PNG_READ_iCCP_SUPPORTED
172 #ifdef PNG_READ_iTXt_SUPPORTED
175 #ifdef PNG_READ_oFFs_SUPPORTED
178 #ifdef PNG_READ_pCAL_SUPPORTED
181 #ifdef PNG_READ_pHYs_SUPPORTED
184 #ifdef PNG_READ_sBIT_SUPPORTED
187 #ifdef PNG_READ_sCAL_SUPPORTED
190 #ifdef PNG_READ_sRGB_SUPPORTED
193 #ifdef PNG_READ_sPLT_SUPPORTED
196 #ifdef PNG_READ_tEXt_SUPPORTED
199 #ifdef PNG_READ_tIME_SUPPORTED
202 #ifdef PNG_READ_tRNS_SUPPORTED
205 #ifdef PNG_READ_zTXt_SUPPORTED
209 /* First we make sure we have enough data for the 4 byte chunk name
210 * and the 4 byte chunk length before proceeding with decoding the
211 * chunk data. To fully decode each of these chunks, we also make
212 * sure we have enough data in the buffer for the 4 byte CRC at the
213 * end of every chunk (except IDAT, which is handled separately).
215 if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
217 png_byte chunk_length[4];
219 if (png_ptr->buffer_size < 8)
221 png_push_save_buffer(png_ptr);
225 png_push_fill_buffer(png_ptr, chunk_length, 4);
226 png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
227 png_reset_crc(png_ptr);
228 png_crc_read(png_ptr, png_ptr->chunk_name, 4);
229 png_check_chunk_name(png_ptr, png_ptr->chunk_name);
230 png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
233 if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
234 if (png_ptr->mode & PNG_AFTER_IDAT)
235 png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
237 if (!png_memcmp(png_ptr->chunk_name, png_IHDR, 4))
239 if (png_ptr->push_length != 13)
240 png_error(png_ptr, "Invalid IHDR length");
242 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
244 png_push_save_buffer(png_ptr);
248 png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length);
251 else if (!png_memcmp(png_ptr->chunk_name, png_IEND, 4))
253 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
255 png_push_save_buffer(png_ptr);
259 png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length);
261 png_ptr->process_mode = PNG_READ_DONE_MODE;
262 png_push_have_end(png_ptr, info_ptr);
265 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
266 else if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name))
268 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
270 png_push_save_buffer(png_ptr);
274 if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
275 png_ptr->mode |= PNG_HAVE_IDAT;
277 png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length);
279 if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
280 png_ptr->mode |= PNG_HAVE_PLTE;
282 else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
284 if (!(png_ptr->mode & PNG_HAVE_IHDR))
285 png_error(png_ptr, "Missing IHDR before IDAT");
287 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
288 !(png_ptr->mode & PNG_HAVE_PLTE))
289 png_error(png_ptr, "Missing PLTE before IDAT");
294 else if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
296 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
298 png_push_save_buffer(png_ptr);
301 png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
304 else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
306 /* If we reach an IDAT chunk, this means we have read all of the
307 * header chunks, and we can start reading the image (or if this
308 * is called after the image has been read - we have an error).
311 if (!(png_ptr->mode & PNG_HAVE_IHDR))
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))
316 png_error(png_ptr, "Missing PLTE before IDAT");
318 if (png_ptr->mode & PNG_HAVE_IDAT)
320 if (!(png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
321 if (png_ptr->push_length == 0)
324 if (png_ptr->mode & PNG_AFTER_IDAT)
325 png_benign_error(png_ptr, "Too many IDATs found");
328 png_ptr->idat_size = png_ptr->push_length;
329 png_ptr->mode |= PNG_HAVE_IDAT;
330 png_ptr->process_mode = PNG_READ_IDAT_MODE;
331 png_push_have_info(png_ptr, info_ptr);
332 png_ptr->zstream.avail_out = (uInt)png_ptr->irowbytes;
333 png_ptr->zstream.next_out = png_ptr->row_buf;
337 #ifdef PNG_READ_gAMA_SUPPORTED
338 else if (!png_memcmp(png_ptr->chunk_name, png_gAMA, 4))
340 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
342 png_push_save_buffer(png_ptr);
346 png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length);
350 #ifdef PNG_READ_sBIT_SUPPORTED
351 else if (!png_memcmp(png_ptr->chunk_name, png_sBIT, 4))
353 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
355 png_push_save_buffer(png_ptr);
359 png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length);
363 #ifdef PNG_READ_cHRM_SUPPORTED
364 else if (!png_memcmp(png_ptr->chunk_name, png_cHRM, 4))
366 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
368 png_push_save_buffer(png_ptr);
372 png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length);
376 #ifdef PNG_READ_sRGB_SUPPORTED
377 else if (!png_memcmp(png_ptr->chunk_name, png_sRGB, 4))
379 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
381 png_push_save_buffer(png_ptr);
385 png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length);
389 #ifdef PNG_READ_iCCP_SUPPORTED
390 else if (!png_memcmp(png_ptr->chunk_name, png_iCCP, 4))
392 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
394 png_push_save_buffer(png_ptr);
398 png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length);
402 #ifdef PNG_READ_sPLT_SUPPORTED
403 else if (!png_memcmp(png_ptr->chunk_name, png_sPLT, 4))
405 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
407 png_push_save_buffer(png_ptr);
411 png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length);
415 #ifdef PNG_READ_tRNS_SUPPORTED
416 else if (!png_memcmp(png_ptr->chunk_name, png_tRNS, 4))
418 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
420 png_push_save_buffer(png_ptr);
424 png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length);
428 #ifdef PNG_READ_bKGD_SUPPORTED
429 else if (!png_memcmp(png_ptr->chunk_name, png_bKGD, 4))
431 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
433 png_push_save_buffer(png_ptr);
437 png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length);
441 #ifdef PNG_READ_hIST_SUPPORTED
442 else if (!png_memcmp(png_ptr->chunk_name, png_hIST, 4))
444 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
446 png_push_save_buffer(png_ptr);
450 png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length);
454 #ifdef PNG_READ_pHYs_SUPPORTED
455 else if (!png_memcmp(png_ptr->chunk_name, png_pHYs, 4))
457 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
459 png_push_save_buffer(png_ptr);
463 png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length);
467 #ifdef PNG_READ_oFFs_SUPPORTED
468 else if (!png_memcmp(png_ptr->chunk_name, png_oFFs, 4))
470 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
472 png_push_save_buffer(png_ptr);
476 png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length);
480 #ifdef PNG_READ_pCAL_SUPPORTED
481 else if (!png_memcmp(png_ptr->chunk_name, png_pCAL, 4))
483 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
485 png_push_save_buffer(png_ptr);
489 png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length);
493 #ifdef PNG_READ_sCAL_SUPPORTED
494 else if (!png_memcmp(png_ptr->chunk_name, png_sCAL, 4))
496 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
498 png_push_save_buffer(png_ptr);
502 png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length);
506 #ifdef PNG_READ_tIME_SUPPORTED
507 else if (!png_memcmp(png_ptr->chunk_name, png_tIME, 4))
509 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
511 png_push_save_buffer(png_ptr);
515 png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length);
519 #ifdef PNG_READ_tEXt_SUPPORTED
520 else if (!png_memcmp(png_ptr->chunk_name, png_tEXt, 4))
522 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
524 png_push_save_buffer(png_ptr);
528 png_push_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length);
532 #ifdef PNG_READ_zTXt_SUPPORTED
533 else if (!png_memcmp(png_ptr->chunk_name, png_zTXt, 4))
535 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
537 png_push_save_buffer(png_ptr);
541 png_push_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
545 #ifdef PNG_READ_iTXt_SUPPORTED
546 else if (!png_memcmp(png_ptr->chunk_name, png_iTXt, 4))
548 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
550 png_push_save_buffer(png_ptr);
554 png_push_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
560 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
562 png_push_save_buffer(png_ptr);
565 png_push_handle_unknown(png_ptr, info_ptr, png_ptr->push_length);
568 png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
572 png_push_crc_skip(png_structp png_ptr, png_uint_32 skip)
574 png_ptr->process_mode = PNG_SKIP_MODE;
575 png_ptr->skip_length = skip;
579 png_push_crc_finish(png_structp png_ptr)
581 if (png_ptr->skip_length && png_ptr->save_buffer_size)
583 png_size_t save_size;
585 if (png_ptr->skip_length < (png_uint_32)png_ptr->save_buffer_size)
586 save_size = (png_size_t)png_ptr->skip_length;
588 save_size = png_ptr->save_buffer_size;
590 png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
592 png_ptr->skip_length -= save_size;
593 png_ptr->buffer_size -= save_size;
594 png_ptr->save_buffer_size -= save_size;
595 png_ptr->save_buffer_ptr += save_size;
597 if (png_ptr->skip_length && png_ptr->current_buffer_size)
599 png_size_t save_size;
601 if (png_ptr->skip_length < (png_uint_32)png_ptr->current_buffer_size)
602 save_size = (png_size_t)png_ptr->skip_length;
604 save_size = png_ptr->current_buffer_size;
606 png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
608 png_ptr->skip_length -= save_size;
609 png_ptr->buffer_size -= save_size;
610 png_ptr->current_buffer_size -= save_size;
611 png_ptr->current_buffer_ptr += save_size;
613 if (!png_ptr->skip_length)
615 if (png_ptr->buffer_size < 4)
617 png_push_save_buffer(png_ptr);
621 png_crc_finish(png_ptr, 0);
622 png_ptr->process_mode = PNG_READ_CHUNK_MODE;
627 png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
635 if (png_ptr->save_buffer_size)
637 png_size_t save_size;
639 if (length < png_ptr->save_buffer_size)
642 save_size = png_ptr->save_buffer_size;
644 png_memcpy(ptr, png_ptr->save_buffer_ptr, save_size);
647 png_ptr->buffer_size -= save_size;
648 png_ptr->save_buffer_size -= save_size;
649 png_ptr->save_buffer_ptr += save_size;
651 if (length && png_ptr->current_buffer_size)
653 png_size_t save_size;
655 if (length < png_ptr->current_buffer_size)
659 save_size = png_ptr->current_buffer_size;
661 png_memcpy(ptr, png_ptr->current_buffer_ptr, save_size);
662 png_ptr->buffer_size -= save_size;
663 png_ptr->current_buffer_size -= save_size;
664 png_ptr->current_buffer_ptr += save_size;
669 png_push_save_buffer(png_structp png_ptr)
671 if (png_ptr->save_buffer_size)
673 if (png_ptr->save_buffer_ptr != png_ptr->save_buffer)
679 istop = png_ptr->save_buffer_size;
680 for (i = 0, sp = png_ptr->save_buffer_ptr, dp = png_ptr->save_buffer;
681 i < istop; i++, sp++, dp++)
687 if (png_ptr->save_buffer_size + png_ptr->current_buffer_size >
688 png_ptr->save_buffer_max)
691 png_bytep old_buffer;
693 if (png_ptr->save_buffer_size > PNG_SIZE_MAX -
694 (png_ptr->current_buffer_size + 256))
696 png_error(png_ptr, "Potential overflow of save_buffer");
699 new_max = png_ptr->save_buffer_size + png_ptr->current_buffer_size + 256;
700 old_buffer = png_ptr->save_buffer;
701 png_ptr->save_buffer = (png_bytep)png_malloc(png_ptr,
702 (png_size_t)new_max);
703 png_memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size);
704 png_free(png_ptr, old_buffer);
705 png_ptr->save_buffer_max = new_max;
707 if (png_ptr->current_buffer_size)
709 png_memcpy(png_ptr->save_buffer + png_ptr->save_buffer_size,
710 png_ptr->current_buffer_ptr, png_ptr->current_buffer_size);
711 png_ptr->save_buffer_size += png_ptr->current_buffer_size;
712 png_ptr->current_buffer_size = 0;
714 png_ptr->save_buffer_ptr = png_ptr->save_buffer;
715 png_ptr->buffer_size = 0;
719 png_push_restore_buffer(png_structp png_ptr, png_bytep buffer,
720 png_size_t buffer_length)
722 png_ptr->current_buffer = buffer;
723 png_ptr->current_buffer_size = buffer_length;
724 png_ptr->buffer_size = buffer_length + png_ptr->save_buffer_size;
725 png_ptr->current_buffer_ptr = png_ptr->current_buffer;
729 png_push_read_IDAT(png_structp png_ptr)
732 if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
734 png_byte chunk_length[4];
736 if (png_ptr->buffer_size < 8)
738 png_push_save_buffer(png_ptr);
742 png_push_fill_buffer(png_ptr, chunk_length, 4);
743 png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
744 png_reset_crc(png_ptr);
745 png_crc_read(png_ptr, png_ptr->chunk_name, 4);
746 png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
748 if (png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
750 png_ptr->process_mode = PNG_READ_CHUNK_MODE;
751 if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
752 png_error(png_ptr, "Not enough compressed data");
756 png_ptr->idat_size = png_ptr->push_length;
758 if (png_ptr->idat_size && png_ptr->save_buffer_size)
760 png_size_t save_size;
762 if (png_ptr->idat_size < (png_uint_32)png_ptr->save_buffer_size)
764 save_size = (png_size_t)png_ptr->idat_size;
766 /* Check for overflow */
767 if ((png_uint_32)save_size != png_ptr->idat_size)
768 png_error(png_ptr, "save_size overflowed in pngpread");
771 save_size = png_ptr->save_buffer_size;
773 png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
775 if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
776 png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size);
778 png_ptr->idat_size -= save_size;
779 png_ptr->buffer_size -= save_size;
780 png_ptr->save_buffer_size -= save_size;
781 png_ptr->save_buffer_ptr += save_size;
783 if (png_ptr->idat_size && png_ptr->current_buffer_size)
785 png_size_t save_size;
787 if (png_ptr->idat_size < (png_uint_32)png_ptr->current_buffer_size)
789 save_size = (png_size_t)png_ptr->idat_size;
791 /* Check for overflow */
792 if ((png_uint_32)save_size != png_ptr->idat_size)
793 png_error(png_ptr, "save_size overflowed in pngpread");
796 save_size = png_ptr->current_buffer_size;
798 png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
799 if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
800 png_process_IDAT_data(png_ptr, png_ptr->current_buffer_ptr, save_size);
802 png_ptr->idat_size -= save_size;
803 png_ptr->buffer_size -= save_size;
804 png_ptr->current_buffer_size -= save_size;
805 png_ptr->current_buffer_ptr += save_size;
807 if (!png_ptr->idat_size)
809 if (png_ptr->buffer_size < 4)
811 png_push_save_buffer(png_ptr);
815 png_crc_finish(png_ptr, 0);
816 png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
817 png_ptr->mode |= PNG_AFTER_IDAT;
822 png_process_IDAT_data(png_structp png_ptr, png_bytep buffer,
823 png_size_t buffer_length)
827 if ((png_ptr->flags & PNG_FLAG_ZLIB_FINISHED) && buffer_length)
828 png_benign_error(png_ptr, "Extra compression data");
830 png_ptr->zstream.next_in = buffer;
831 png_ptr->zstream.avail_in = (uInt)buffer_length;
834 ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
837 if (ret == Z_STREAM_END)
839 if (png_ptr->zstream.avail_in)
840 png_benign_error(png_ptr, "Extra compressed data");
842 if (!(png_ptr->zstream.avail_out))
844 png_push_process_row(png_ptr);
847 png_ptr->mode |= PNG_AFTER_IDAT;
848 png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
851 else if (ret == Z_BUF_ERROR)
855 png_error(png_ptr, "Decompression Error");
857 if (!(png_ptr->zstream.avail_out))
860 #ifdef PNG_READ_INTERLACING_SUPPORTED
861 png_ptr->interlaced && png_ptr->pass > 6) ||
862 (!png_ptr->interlaced &&
864 png_ptr->row_number == png_ptr->num_rows))
866 if (png_ptr->zstream.avail_in)
867 png_warning(png_ptr, "Too much data in IDAT chunks");
868 png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
871 png_push_process_row(png_ptr);
872 png_ptr->zstream.avail_out = (uInt)png_ptr->irowbytes;
873 png_ptr->zstream.next_out = png_ptr->row_buf;
882 png_push_process_row(png_structp png_ptr)
884 png_ptr->row_info.color_type = png_ptr->color_type;
885 png_ptr->row_info.width = png_ptr->iwidth;
886 png_ptr->row_info.channels = png_ptr->channels;
887 png_ptr->row_info.bit_depth = png_ptr->bit_depth;
888 png_ptr->row_info.pixel_depth = png_ptr->pixel_depth;
890 png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth,
891 png_ptr->row_info.width);
893 png_read_filter_row(png_ptr, &(png_ptr->row_info),
894 png_ptr->row_buf + 1, png_ptr->prev_row + 1,
895 (int)(png_ptr->row_buf[0]));
897 png_memcpy(png_ptr->prev_row, png_ptr->row_buf, png_ptr->rowbytes + 1);
899 if (png_ptr->transformations || (png_ptr->flags&PNG_FLAG_STRIP_ALPHA))
900 png_do_read_transformations(png_ptr);
902 #ifdef PNG_READ_INTERLACING_SUPPORTED
903 /* Blow up interlaced rows to full size */
904 if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
906 if (png_ptr->pass < 6)
907 /* old interface (pre-1.0.9):
908 png_do_read_interlace(&(png_ptr->row_info),
909 png_ptr->row_buf + 1, png_ptr->pass, png_ptr->transformations);
911 png_do_read_interlace(png_ptr);
913 switch (png_ptr->pass)
918 for (i = 0; i < 8 && png_ptr->pass == 0; i++)
920 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
921 png_read_push_finish_row(png_ptr); /* Updates png_ptr->pass */
924 if (png_ptr->pass == 2) /* Pass 1 might be empty */
926 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
928 png_push_have_row(png_ptr, NULL);
929 png_read_push_finish_row(png_ptr);
933 if (png_ptr->pass == 4 && png_ptr->height <= 4)
935 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
937 png_push_have_row(png_ptr, NULL);
938 png_read_push_finish_row(png_ptr);
942 if (png_ptr->pass == 6 && png_ptr->height <= 4)
944 png_push_have_row(png_ptr, NULL);
945 png_read_push_finish_row(png_ptr);
954 for (i = 0; i < 8 && png_ptr->pass == 1; i++)
956 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
957 png_read_push_finish_row(png_ptr);
960 if (png_ptr->pass == 2) /* Skip top 4 generated rows */
962 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
964 png_push_have_row(png_ptr, NULL);
965 png_read_push_finish_row(png_ptr);
976 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
978 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
979 png_read_push_finish_row(png_ptr);
982 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
984 png_push_have_row(png_ptr, NULL);
985 png_read_push_finish_row(png_ptr);
988 if (png_ptr->pass == 4) /* Pass 3 might be empty */
990 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
992 png_push_have_row(png_ptr, NULL);
993 png_read_push_finish_row(png_ptr);
1004 for (i = 0; i < 4 && png_ptr->pass == 3; i++)
1006 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1007 png_read_push_finish_row(png_ptr);
1010 if (png_ptr->pass == 4) /* Skip top two generated rows */
1012 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
1014 png_push_have_row(png_ptr, NULL);
1015 png_read_push_finish_row(png_ptr);
1026 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
1028 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1029 png_read_push_finish_row(png_ptr);
1032 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
1034 png_push_have_row(png_ptr, NULL);
1035 png_read_push_finish_row(png_ptr);
1038 if (png_ptr->pass == 6) /* Pass 5 might be empty */
1040 png_push_have_row(png_ptr, NULL);
1041 png_read_push_finish_row(png_ptr);
1051 for (i = 0; i < 2 && png_ptr->pass == 5; i++)
1053 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1054 png_read_push_finish_row(png_ptr);
1057 if (png_ptr->pass == 6) /* Skip top generated row */
1059 png_push_have_row(png_ptr, NULL);
1060 png_read_push_finish_row(png_ptr);
1067 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1068 png_read_push_finish_row(png_ptr);
1070 if (png_ptr->pass != 6)
1073 png_push_have_row(png_ptr, NULL);
1074 png_read_push_finish_row(png_ptr);
1081 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
1082 png_read_push_finish_row(png_ptr);
1087 png_read_push_finish_row(png_structp png_ptr)
1089 /* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
1091 /* Start of interlace block */
1092 PNG_CONST int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
1094 /* Offset to next interlace block */
1095 PNG_CONST int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
1097 /* Start of interlace block in the y direction */
1098 PNG_CONST int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
1100 /* Offset to next interlace block in the y direction */
1101 PNG_CONST int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
1103 /* Height of interlace block. This is not currently used - if you need
1104 * it, uncomment it here and in png.h
1105 PNG_CONST int FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
1108 png_ptr->row_number++;
1109 if (png_ptr->row_number < png_ptr->num_rows)
1112 #ifdef PNG_READ_INTERLACING_SUPPORTED
1113 if (png_ptr->interlaced)
1115 png_ptr->row_number = 0;
1116 png_memset(png_ptr->prev_row, 0,
1117 png_ptr->rowbytes + 1);
1121 if ((png_ptr->pass == 1 && png_ptr->width < 5) ||
1122 (png_ptr->pass == 3 && png_ptr->width < 3) ||
1123 (png_ptr->pass == 5 && png_ptr->width < 2))
1126 if (png_ptr->pass > 7)
1129 if (png_ptr->pass >= 7)
1132 png_ptr->iwidth = (png_ptr->width +
1133 png_pass_inc[png_ptr->pass] - 1 -
1134 png_pass_start[png_ptr->pass]) /
1135 png_pass_inc[png_ptr->pass];
1137 png_ptr->irowbytes = PNG_ROWBYTES(png_ptr->pixel_depth,
1138 png_ptr->iwidth) + 1;
1140 if (png_ptr->transformations & PNG_INTERLACE)
1143 png_ptr->num_rows = (png_ptr->height +
1144 png_pass_yinc[png_ptr->pass] - 1 -
1145 png_pass_ystart[png_ptr->pass]) /
1146 png_pass_yinc[png_ptr->pass];
1148 } while (png_ptr->iwidth == 0 || png_ptr->num_rows == 0);
1150 #endif /* PNG_READ_INTERLACING_SUPPORTED */
1153 #ifdef PNG_READ_tEXt_SUPPORTED
1155 png_push_handle_tEXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
1158 if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
1160 png_error(png_ptr, "Out of place tEXt");
1161 info_ptr = info_ptr; /* To quiet some compiler warnings */
1164 #ifdef PNG_MAX_MALLOC_64K
1165 png_ptr->skip_length = 0; /* This may not be necessary */
1167 if (length > (png_uint_32)65535L) /* Can't hold entire string in memory */
1169 png_warning(png_ptr, "tEXt chunk too large to fit in memory");
1170 png_ptr->skip_length = length - (png_uint_32)65535L;
1171 length = (png_uint_32)65535L;
1175 png_ptr->current_text = (png_charp)png_malloc(png_ptr,
1176 (png_size_t)(length + 1));
1177 png_ptr->current_text[length] = '\0';
1178 png_ptr->current_text_ptr = png_ptr->current_text;
1179 png_ptr->current_text_size = (png_size_t)length;
1180 png_ptr->current_text_left = (png_size_t)length;
1181 png_ptr->process_mode = PNG_READ_tEXt_MODE;
1185 png_push_read_tEXt(png_structp png_ptr, png_infop info_ptr)
1187 if (png_ptr->buffer_size && png_ptr->current_text_left)
1189 png_size_t text_size;
1191 if (png_ptr->buffer_size < png_ptr->current_text_left)
1192 text_size = png_ptr->buffer_size;
1195 text_size = png_ptr->current_text_left;
1197 png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
1198 png_ptr->current_text_left -= text_size;
1199 png_ptr->current_text_ptr += text_size;
1201 if (!(png_ptr->current_text_left))
1208 if (png_ptr->buffer_size < 4)
1210 png_push_save_buffer(png_ptr);
1214 png_push_crc_finish(png_ptr);
1216 #ifdef PNG_MAX_MALLOC_64K
1217 if (png_ptr->skip_length)
1221 key = png_ptr->current_text;
1223 for (text = key; *text; text++)
1226 if (text < key + png_ptr->current_text_size)
1229 text_ptr = (png_textp)png_malloc(png_ptr,
1230 png_sizeof(png_text));
1231 text_ptr->compression = PNG_TEXT_COMPRESSION_NONE;
1232 text_ptr->key = key;
1233 #ifdef PNG_iTXt_SUPPORTED
1234 text_ptr->lang = NULL;
1235 text_ptr->lang_key = NULL;
1237 text_ptr->text = text;
1239 ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
1241 png_free(png_ptr, key);
1242 png_free(png_ptr, text_ptr);
1243 png_ptr->current_text = NULL;
1246 png_warning(png_ptr, "Insufficient memory to store text chunk");
1251 #ifdef PNG_READ_zTXt_SUPPORTED
1253 png_push_handle_zTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
1256 if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
1258 png_error(png_ptr, "Out of place zTXt");
1259 info_ptr = info_ptr; /* To quiet some compiler warnings */
1262 #ifdef PNG_MAX_MALLOC_64K
1263 /* We can't handle zTXt chunks > 64K, since we don't have enough space
1264 * to be able to store the uncompressed data. Actually, the threshold
1265 * is probably around 32K, but it isn't as definite as 64K is.
1267 if (length > (png_uint_32)65535L)
1269 png_warning(png_ptr, "zTXt chunk too large to fit in memory");
1270 png_push_crc_skip(png_ptr, length);
1275 png_ptr->current_text = (png_charp)png_malloc(png_ptr,
1276 (png_size_t)(length + 1));
1277 png_ptr->current_text[length] = '\0';
1278 png_ptr->current_text_ptr = png_ptr->current_text;
1279 png_ptr->current_text_size = (png_size_t)length;
1280 png_ptr->current_text_left = (png_size_t)length;
1281 png_ptr->process_mode = PNG_READ_zTXt_MODE;
1285 png_push_read_zTXt(png_structp png_ptr, png_infop info_ptr)
1287 if (png_ptr->buffer_size && png_ptr->current_text_left)
1289 png_size_t text_size;
1291 if (png_ptr->buffer_size < (png_uint_32)png_ptr->current_text_left)
1292 text_size = png_ptr->buffer_size;
1295 text_size = png_ptr->current_text_left;
1297 png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
1298 png_ptr->current_text_left -= text_size;
1299 png_ptr->current_text_ptr += text_size;
1301 if (!(png_ptr->current_text_left))
1307 png_size_t text_size, key_size;
1309 if (png_ptr->buffer_size < 4)
1311 png_push_save_buffer(png_ptr);
1315 png_push_crc_finish(png_ptr);
1317 key = png_ptr->current_text;
1319 for (text = key; *text; text++)
1322 /* zTXt can't have zero text */
1323 if (text >= key + png_ptr->current_text_size)
1325 png_ptr->current_text = NULL;
1326 png_free(png_ptr, key);
1332 if (*text != PNG_TEXT_COMPRESSION_zTXt) /* Check compression byte */
1334 png_ptr->current_text = NULL;
1335 png_free(png_ptr, key);
1341 png_ptr->zstream.next_in = (png_bytep )text;
1342 png_ptr->zstream.avail_in = (uInt)(png_ptr->current_text_size -
1344 png_ptr->zstream.next_out = png_ptr->zbuf;
1345 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
1347 key_size = text - key;
1352 while (png_ptr->zstream.avail_in)
1354 ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
1355 if (ret != Z_OK && ret != Z_STREAM_END)
1357 inflateReset(&png_ptr->zstream);
1358 png_ptr->zstream.avail_in = 0;
1359 png_ptr->current_text = NULL;
1360 png_free(png_ptr, key);
1361 png_free(png_ptr, text);
1364 if (!(png_ptr->zstream.avail_out) || ret == Z_STREAM_END)
1368 text = (png_charp)png_malloc(png_ptr,
1370 - png_ptr->zstream.avail_out + key_size + 1));
1372 png_memcpy(text + key_size, png_ptr->zbuf,
1373 png_ptr->zbuf_size - png_ptr->zstream.avail_out);
1375 png_memcpy(text, key, key_size);
1377 text_size = key_size + png_ptr->zbuf_size -
1378 png_ptr->zstream.avail_out;
1380 *(text + text_size) = '\0';
1387 text = (png_charp)png_malloc(png_ptr, text_size +
1389 - png_ptr->zstream.avail_out + 1));
1391 png_memcpy(text, tmp, text_size);
1392 png_free(png_ptr, tmp);
1394 png_memcpy(text + text_size, png_ptr->zbuf,
1395 png_ptr->zbuf_size - png_ptr->zstream.avail_out);
1397 text_size += png_ptr->zbuf_size - png_ptr->zstream.avail_out;
1398 *(text + text_size) = '\0';
1400 if (ret != Z_STREAM_END)
1402 png_ptr->zstream.next_out = png_ptr->zbuf;
1403 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
1411 if (ret == Z_STREAM_END)
1415 inflateReset(&png_ptr->zstream);
1416 png_ptr->zstream.avail_in = 0;
1418 if (ret != Z_STREAM_END)
1420 png_ptr->current_text = NULL;
1421 png_free(png_ptr, key);
1422 png_free(png_ptr, text);
1426 png_ptr->current_text = NULL;
1427 png_free(png_ptr, key);
1431 text_ptr = (png_textp)png_malloc(png_ptr,
1432 png_sizeof(png_text));
1433 text_ptr->compression = PNG_TEXT_COMPRESSION_zTXt;
1434 text_ptr->key = key;
1435 #ifdef PNG_iTXt_SUPPORTED
1436 text_ptr->lang = NULL;
1437 text_ptr->lang_key = NULL;
1439 text_ptr->text = text;
1441 ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
1443 png_free(png_ptr, key);
1444 png_free(png_ptr, text_ptr);
1447 png_warning(png_ptr, "Insufficient memory to store text chunk");
1452 #ifdef PNG_READ_iTXt_SUPPORTED
1454 png_push_handle_iTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
1457 if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
1459 png_error(png_ptr, "Out of place iTXt");
1460 info_ptr = info_ptr; /* To quiet some compiler warnings */
1463 #ifdef PNG_MAX_MALLOC_64K
1464 png_ptr->skip_length = 0; /* This may not be necessary */
1466 if (length > (png_uint_32)65535L) /* Can't hold entire string in memory */
1468 png_warning(png_ptr, "iTXt chunk too large to fit in memory");
1469 png_ptr->skip_length = length - (png_uint_32)65535L;
1470 length = (png_uint_32)65535L;
1474 png_ptr->current_text = (png_charp)png_malloc(png_ptr,
1475 (png_size_t)(length + 1));
1476 png_ptr->current_text[length] = '\0';
1477 png_ptr->current_text_ptr = png_ptr->current_text;
1478 png_ptr->current_text_size = (png_size_t)length;
1479 png_ptr->current_text_left = (png_size_t)length;
1480 png_ptr->process_mode = PNG_READ_iTXt_MODE;
1484 png_push_read_iTXt(png_structp png_ptr, png_infop info_ptr)
1487 if (png_ptr->buffer_size && png_ptr->current_text_left)
1489 png_size_t text_size;
1491 if (png_ptr->buffer_size < png_ptr->current_text_left)
1492 text_size = png_ptr->buffer_size;
1495 text_size = png_ptr->current_text_left;
1497 png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
1498 png_ptr->current_text_left -= text_size;
1499 png_ptr->current_text_ptr += text_size;
1501 if (!(png_ptr->current_text_left))
1511 if (png_ptr->buffer_size < 4)
1513 png_push_save_buffer(png_ptr);
1517 png_push_crc_finish(png_ptr);
1519 #ifdef PNG_MAX_MALLOC_64K
1520 if (png_ptr->skip_length)
1524 key = png_ptr->current_text;
1526 for (lang = key; *lang; lang++)
1529 if (lang < key + png_ptr->current_text_size - 3)
1532 comp_flag = *lang++;
1533 lang++; /* Skip comp_type, always zero */
1535 for (lang_key = lang; *lang_key; lang_key++)
1538 lang_key++; /* Skip NUL separator */
1542 if (lang_key < key + png_ptr->current_text_size - 1)
1544 for (; *text; text++)
1548 if (text < key + png_ptr->current_text_size)
1551 text_ptr = (png_textp)png_malloc(png_ptr,
1552 png_sizeof(png_text));
1554 text_ptr->compression = comp_flag + 2;
1555 text_ptr->key = key;
1556 text_ptr->lang = lang;
1557 text_ptr->lang_key = lang_key;
1558 text_ptr->text = text;
1559 text_ptr->text_length = 0;
1560 text_ptr->itxt_length = png_strlen(text);
1562 ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
1564 png_ptr->current_text = NULL;
1566 png_free(png_ptr, text_ptr);
1568 png_warning(png_ptr, "Insufficient memory to store iTXt chunk");
1573 /* This function is called when we haven't found a handler for this
1574 * chunk. If there isn't a problem with the chunk itself (ie a bad chunk
1575 * name or a critical chunk), the chunk is (currently) silently ignored.
1578 png_push_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32
1581 png_uint_32 skip = 0;
1583 if (!(png_ptr->chunk_name[0] & 0x20))
1585 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
1586 if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
1587 PNG_HANDLE_CHUNK_ALWAYS
1588 #ifdef PNG_READ_USER_CHUNKS_SUPPORTED
1589 && png_ptr->read_user_chunk_fn == NULL
1593 png_chunk_error(png_ptr, "unknown critical chunk");
1595 info_ptr = info_ptr; /* To quiet some compiler warnings */
1598 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
1599 if (png_ptr->flags & PNG_FLAG_KEEP_UNKNOWN_CHUNKS)
1601 #ifdef PNG_MAX_MALLOC_64K
1602 if (length > (png_uint_32)65535L)
1604 png_warning(png_ptr, "unknown chunk too large to fit in memory");
1605 skip = length - (png_uint_32)65535L;
1606 length = (png_uint_32)65535L;
1609 png_memcpy((png_charp)png_ptr->unknown_chunk.name,
1610 (png_charp)png_ptr->chunk_name,
1611 png_sizeof(png_ptr->unknown_chunk.name));
1612 png_ptr->unknown_chunk.name[png_sizeof(png_ptr->unknown_chunk.name) - 1]
1615 png_ptr->unknown_chunk.size = (png_size_t)length;
1618 png_ptr->unknown_chunk.data = NULL;
1622 png_ptr->unknown_chunk.data = (png_bytep)png_malloc(png_ptr,
1623 (png_size_t)length);
1624 png_crc_read(png_ptr, (png_bytep)png_ptr->unknown_chunk.data, length);
1627 #ifdef PNG_READ_USER_CHUNKS_SUPPORTED
1628 if (png_ptr->read_user_chunk_fn != NULL)
1630 /* Callback to user unknown chunk handler */
1632 ret = (*(png_ptr->read_user_chunk_fn))
1633 (png_ptr, &png_ptr->unknown_chunk);
1636 png_chunk_error(png_ptr, "error in user chunk");
1640 if (!(png_ptr->chunk_name[0] & 0x20))
1641 if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
1642 PNG_HANDLE_CHUNK_ALWAYS)
1643 png_chunk_error(png_ptr, "unknown critical chunk");
1644 png_set_unknown_chunks(png_ptr, info_ptr,
1645 &png_ptr->unknown_chunk, 1);
1651 png_set_unknown_chunks(png_ptr, info_ptr, &png_ptr->unknown_chunk, 1);
1652 png_free(png_ptr, png_ptr->unknown_chunk.data);
1653 png_ptr->unknown_chunk.data = NULL;
1659 png_push_crc_skip(png_ptr, skip);
1663 png_push_have_info(png_structp png_ptr, png_infop info_ptr)
1665 if (png_ptr->info_fn != NULL)
1666 (*(png_ptr->info_fn))(png_ptr, info_ptr);
1670 png_push_have_end(png_structp png_ptr, png_infop info_ptr)
1672 if (png_ptr->end_fn != NULL)
1673 (*(png_ptr->end_fn))(png_ptr, info_ptr);
1677 png_push_have_row(png_structp png_ptr, png_bytep row)
1679 if (png_ptr->row_fn != NULL)
1680 (*(png_ptr->row_fn))(png_ptr, row, png_ptr->row_number,
1681 (int)png_ptr->pass);
1685 png_progressive_combine_row (png_structp png_ptr,
1686 png_bytep old_row, png_bytep new_row)
1688 PNG_CONST int FARDATA png_pass_dsp_mask[7] =
1689 {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
1691 if (png_ptr == NULL)
1694 if (new_row != NULL) /* new_row must == png_ptr->row_buf here. */
1695 png_combine_row(png_ptr, old_row, png_pass_dsp_mask[png_ptr->pass]);
1699 png_set_progressive_read_fn(png_structp png_ptr, png_voidp progressive_ptr,
1700 png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,
1701 png_progressive_end_ptr end_fn)
1703 if (png_ptr == NULL)
1706 png_ptr->info_fn = info_fn;
1707 png_ptr->row_fn = row_fn;
1708 png_ptr->end_fn = end_fn;
1710 png_set_read_fn(png_ptr, progressive_ptr, png_push_fill_buffer);
1714 png_get_progressive_ptr(png_structp png_ptr)
1716 if (png_ptr == NULL)
1719 return png_ptr->io_ptr;
1721 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */