2 /* pngpread.c - read a png file in push mode
4 * libpng 1.0.9 - January 31, 2001
5 * For conditions of distribution and use, see copyright notice in png.h
6 * Copyright (c) 1998-2001 Glenn Randers-Pehrson
7 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
8 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
14 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
16 /* push model modes */
17 #define PNG_READ_SIG_MODE 0
18 #define PNG_READ_CHUNK_MODE 1
19 #define PNG_READ_IDAT_MODE 2
20 #define PNG_SKIP_MODE 3
21 #define PNG_READ_tEXt_MODE 4
22 #define PNG_READ_zTXt_MODE 5
23 #define PNG_READ_DONE_MODE 6
24 #define PNG_READ_iTXt_MODE 7
25 #define PNG_ERROR_MODE 8
28 png_process_data(png_structp png_ptr, png_infop info_ptr,
29 png_bytep buffer, png_size_t buffer_size)
31 png_push_restore_buffer(png_ptr, buffer, buffer_size);
33 while (png_ptr->buffer_size)
35 png_process_some_data(png_ptr, info_ptr);
39 /* What we do with the incoming data depends on what we were previously
40 * doing before we ran out of data...
43 png_process_some_data(png_structp png_ptr, png_infop info_ptr)
45 switch (png_ptr->process_mode)
47 case PNG_READ_SIG_MODE:
49 png_push_read_sig(png_ptr, info_ptr);
52 case PNG_READ_CHUNK_MODE:
54 png_push_read_chunk(png_ptr, info_ptr);
57 case PNG_READ_IDAT_MODE:
59 png_push_read_IDAT(png_ptr);
62 #if defined(PNG_READ_tEXt_SUPPORTED)
63 case PNG_READ_tEXt_MODE:
65 png_push_read_tEXt(png_ptr, info_ptr);
69 #if defined(PNG_READ_zTXt_SUPPORTED)
70 case PNG_READ_zTXt_MODE:
72 png_push_read_zTXt(png_ptr, info_ptr);
76 #if defined(PNG_READ_iTXt_SUPPORTED)
77 case PNG_READ_iTXt_MODE:
79 png_push_read_iTXt(png_ptr, info_ptr);
85 png_push_crc_finish(png_ptr);
90 png_ptr->buffer_size = 0;
96 /* Read any remaining signature bytes from the stream and compare them with
97 * the correct PNG signature. It is possible that this routine is called
98 * with bytes already read from the signature, either because they have been
99 * checked by the calling application, or because of multiple calls to this
103 png_push_read_sig(png_structp png_ptr, png_infop info_ptr)
105 png_size_t num_checked = png_ptr->sig_bytes,
106 num_to_check = 8 - num_checked;
108 if (png_ptr->buffer_size < num_to_check)
110 num_to_check = png_ptr->buffer_size;
113 png_push_fill_buffer(png_ptr, &(info_ptr->signature[num_checked]),
115 png_ptr->sig_bytes = (png_byte)(png_ptr->sig_bytes+num_to_check);
117 if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
119 if (num_checked < 4 &&
120 png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
121 png_error(png_ptr, "Not a PNG file");
123 png_error(png_ptr, "PNG file corrupted by ASCII conversion");
127 if (png_ptr->sig_bytes >= 8)
129 png_ptr->process_mode = PNG_READ_CHUNK_MODE;
135 png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
137 #ifdef PNG_USE_LOCAL_ARRAYS
142 #if defined(PNG_READ_bKGD_SUPPORTED)
145 #if defined(PNG_READ_cHRM_SUPPORTED)
148 #if defined(PNG_READ_gAMA_SUPPORTED)
151 #if defined(PNG_READ_hIST_SUPPORTED)
154 #if defined(PNG_READ_iCCP_SUPPORTED)
157 #if defined(PNG_READ_iTXt_SUPPORTED)
160 #if defined(PNG_READ_oFFs_SUPPORTED)
163 #if defined(PNG_READ_pCAL_SUPPORTED)
166 #if defined(PNG_READ_pHYs_SUPPORTED)
169 #if defined(PNG_READ_sBIT_SUPPORTED)
172 #if defined(PNG_READ_sCAL_SUPPORTED)
175 #if defined(PNG_READ_sRGB_SUPPORTED)
178 #if defined(PNG_READ_sPLT_SUPPORTED)
181 #if defined(PNG_READ_tEXt_SUPPORTED)
184 #if defined(PNG_READ_tIME_SUPPORTED)
187 #if defined(PNG_READ_tRNS_SUPPORTED)
190 #if defined(PNG_READ_zTXt_SUPPORTED)
193 #endif /* PNG_USE_LOCAL_ARRAYS */
194 /* First we make sure we have enough data for the 4 byte chunk name
195 * and the 4 byte chunk length before proceeding with decoding the
196 * chunk data. To fully decode each of these chunks, we also make
197 * sure we have enough data in the buffer for the 4 byte CRC at the
198 * end of every chunk (except IDAT, which is handled separately).
200 if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
202 png_byte chunk_length[4];
204 if (png_ptr->buffer_size < 8)
206 png_push_save_buffer(png_ptr);
210 png_push_fill_buffer(png_ptr, chunk_length, 4);
211 png_ptr->push_length = png_get_uint_32(chunk_length);
212 png_reset_crc(png_ptr);
213 png_crc_read(png_ptr, png_ptr->chunk_name, 4);
214 png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
217 if (!png_memcmp(png_ptr->chunk_name, png_IHDR, 4))
219 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
221 png_push_save_buffer(png_ptr);
225 png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length);
227 else if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
229 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
231 png_push_save_buffer(png_ptr);
235 png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
237 else if (!png_memcmp(png_ptr->chunk_name, (png_bytep)png_IDAT, 4))
239 /* If we reach an IDAT chunk, this means we have read all of the
240 * header chunks, and we can start reading the image (or if this
241 * is called after the image has been read - we have an error).
243 if (png_ptr->mode & PNG_HAVE_IDAT)
245 if (png_ptr->push_length == 0)
248 if (png_ptr->mode & PNG_AFTER_IDAT)
249 png_error(png_ptr, "Too many IDAT's found");
252 png_ptr->idat_size = png_ptr->push_length;
253 png_ptr->mode |= PNG_HAVE_IDAT;
254 png_ptr->process_mode = PNG_READ_IDAT_MODE;
255 png_push_have_info(png_ptr, info_ptr);
256 png_ptr->zstream.avail_out = (uInt)png_ptr->irowbytes;
257 png_ptr->zstream.next_out = png_ptr->row_buf;
260 else if (!png_memcmp(png_ptr->chunk_name, png_IEND, 4))
262 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
264 png_push_save_buffer(png_ptr);
268 png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length);
269 png_ptr->process_mode = PNG_READ_DONE_MODE;
270 png_push_have_end(png_ptr, info_ptr);
272 #if defined(PNG_READ_gAMA_SUPPORTED)
273 else if (!png_memcmp(png_ptr->chunk_name, png_gAMA, 4))
275 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
277 png_push_save_buffer(png_ptr);
281 png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length);
284 #if defined(PNG_READ_sBIT_SUPPORTED)
285 else if (!png_memcmp(png_ptr->chunk_name, png_sBIT, 4))
287 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
289 png_push_save_buffer(png_ptr);
293 png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length);
296 #if defined(PNG_READ_cHRM_SUPPORTED)
297 else if (!png_memcmp(png_ptr->chunk_name, png_cHRM, 4))
299 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
301 png_push_save_buffer(png_ptr);
305 png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length);
308 #if defined(PNG_READ_sRGB_SUPPORTED)
309 else if (!png_memcmp(png_ptr->chunk_name, png_sRGB, 4))
311 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
313 png_push_save_buffer(png_ptr);
317 png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length);
320 #if defined(PNG_READ_iCCP_SUPPORTED)
321 else if (!png_memcmp(png_ptr->chunk_name, png_iCCP, 4))
323 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
325 png_push_save_buffer(png_ptr);
329 png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length);
332 #if defined(PNG_READ_sPLT_SUPPORTED)
333 else if (!png_memcmp(png_ptr->chunk_name, png_sPLT, 4))
335 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
337 png_push_save_buffer(png_ptr);
341 png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length);
344 #if defined(PNG_READ_tRNS_SUPPORTED)
345 else if (!png_memcmp(png_ptr->chunk_name, png_tRNS, 4))
347 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
349 png_push_save_buffer(png_ptr);
353 png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length);
356 #if defined(PNG_READ_bKGD_SUPPORTED)
357 else if (!png_memcmp(png_ptr->chunk_name, png_bKGD, 4))
359 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
361 png_push_save_buffer(png_ptr);
365 png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length);
368 #if defined(PNG_READ_hIST_SUPPORTED)
369 else if (!png_memcmp(png_ptr->chunk_name, png_hIST, 4))
371 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
373 png_push_save_buffer(png_ptr);
377 png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length);
380 #if defined(PNG_READ_pHYs_SUPPORTED)
381 else if (!png_memcmp(png_ptr->chunk_name, png_pHYs, 4))
383 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
385 png_push_save_buffer(png_ptr);
389 png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length);
392 #if defined(PNG_READ_oFFs_SUPPORTED)
393 else if (!png_memcmp(png_ptr->chunk_name, png_oFFs, 4))
395 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
397 png_push_save_buffer(png_ptr);
401 png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length);
404 #if defined(PNG_READ_pCAL_SUPPORTED)
405 else if (!png_memcmp(png_ptr->chunk_name, png_pCAL, 4))
407 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
409 png_push_save_buffer(png_ptr);
413 png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length);
416 #if defined(PNG_READ_sCAL_SUPPORTED)
417 else if (!png_memcmp(png_ptr->chunk_name, png_sCAL, 4))
419 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
421 png_push_save_buffer(png_ptr);
425 png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length);
428 #if defined(PNG_READ_tIME_SUPPORTED)
429 else if (!png_memcmp(png_ptr->chunk_name, png_tIME, 4))
431 if (png_ptr->push_length + 4 > png_ptr->buffer_size)
433 png_push_save_buffer(png_ptr);
437 png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length);
440 #if defined(PNG_READ_tEXt_SUPPORTED)
441 else if (!png_memcmp(png_ptr->chunk_name, png_tEXt, 4))
443 png_push_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length);
446 #if defined(PNG_READ_zTXt_SUPPORTED)
447 else if (!png_memcmp(png_ptr->chunk_name, png_zTXt, 4))
449 png_push_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
452 #if defined(PNG_READ_iTXt_SUPPORTED)
453 else if (!png_memcmp(png_ptr->chunk_name, png_iTXt, 4))
455 png_push_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
460 png_push_handle_unknown(png_ptr, info_ptr, png_ptr->push_length);
463 png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
467 png_push_crc_skip(png_structp png_ptr, png_uint_32 skip)
469 png_ptr->process_mode = PNG_SKIP_MODE;
470 png_ptr->skip_length = skip;
474 png_push_crc_finish(png_structp png_ptr)
476 if (png_ptr->skip_length && png_ptr->save_buffer_size)
478 png_size_t save_size;
480 if (png_ptr->skip_length < (png_uint_32)png_ptr->save_buffer_size)
481 save_size = (png_size_t)png_ptr->skip_length;
483 save_size = png_ptr->save_buffer_size;
485 png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
487 png_ptr->skip_length -= save_size;
488 png_ptr->buffer_size -= save_size;
489 png_ptr->save_buffer_size -= save_size;
490 png_ptr->save_buffer_ptr += save_size;
492 if (png_ptr->skip_length && png_ptr->current_buffer_size)
494 png_size_t save_size;
496 if (png_ptr->skip_length < (png_uint_32)png_ptr->current_buffer_size)
497 save_size = (png_size_t)png_ptr->skip_length;
499 save_size = png_ptr->current_buffer_size;
501 png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
503 png_ptr->skip_length -= save_size;
504 png_ptr->buffer_size -= save_size;
505 png_ptr->current_buffer_size -= save_size;
506 png_ptr->current_buffer_ptr += save_size;
508 if (!png_ptr->skip_length)
510 if (png_ptr->buffer_size < 4)
512 png_push_save_buffer(png_ptr);
516 png_crc_finish(png_ptr, 0);
517 png_ptr->process_mode = PNG_READ_CHUNK_MODE;
522 png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
527 if (png_ptr->save_buffer_size)
529 png_size_t save_size;
531 if (length < png_ptr->save_buffer_size)
534 save_size = png_ptr->save_buffer_size;
536 png_memcpy(ptr, png_ptr->save_buffer_ptr, save_size);
539 png_ptr->buffer_size -= save_size;
540 png_ptr->save_buffer_size -= save_size;
541 png_ptr->save_buffer_ptr += save_size;
543 if (length && png_ptr->current_buffer_size)
545 png_size_t save_size;
547 if (length < png_ptr->current_buffer_size)
550 save_size = png_ptr->current_buffer_size;
552 png_memcpy(ptr, png_ptr->current_buffer_ptr, save_size);
553 png_ptr->buffer_size -= save_size;
554 png_ptr->current_buffer_size -= save_size;
555 png_ptr->current_buffer_ptr += save_size;
560 png_push_save_buffer(png_structp png_ptr)
562 if (png_ptr->save_buffer_size)
564 if (png_ptr->save_buffer_ptr != png_ptr->save_buffer)
570 istop = png_ptr->save_buffer_size;
571 for (i = 0, sp = png_ptr->save_buffer_ptr, dp = png_ptr->save_buffer;
572 i < istop; i++, sp++, dp++)
578 if (png_ptr->save_buffer_size + png_ptr->current_buffer_size >
579 png_ptr->save_buffer_max)
582 png_bytep old_buffer;
584 new_max = png_ptr->save_buffer_size + png_ptr->current_buffer_size + 256;
585 old_buffer = png_ptr->save_buffer;
586 png_ptr->save_buffer = (png_bytep)png_malloc(png_ptr,
587 (png_uint_32)new_max);
588 png_memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size);
589 png_free(png_ptr, old_buffer);
590 png_ptr->save_buffer_max = new_max;
592 if (png_ptr->current_buffer_size)
594 png_memcpy(png_ptr->save_buffer + png_ptr->save_buffer_size,
595 png_ptr->current_buffer_ptr, png_ptr->current_buffer_size);
596 png_ptr->save_buffer_size += png_ptr->current_buffer_size;
597 png_ptr->current_buffer_size = 0;
599 png_ptr->save_buffer_ptr = png_ptr->save_buffer;
600 png_ptr->buffer_size = 0;
604 png_push_restore_buffer(png_structp png_ptr, png_bytep buffer,
605 png_size_t buffer_length)
607 png_ptr->current_buffer = buffer;
608 png_ptr->current_buffer_size = buffer_length;
609 png_ptr->buffer_size = buffer_length + png_ptr->save_buffer_size;
610 png_ptr->current_buffer_ptr = png_ptr->current_buffer;
614 png_push_read_IDAT(png_structp png_ptr)
616 #ifdef PNG_USE_LOCAL_ARRAYS
619 if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
621 png_byte chunk_length[4];
623 if (png_ptr->buffer_size < 8)
625 png_push_save_buffer(png_ptr);
629 png_push_fill_buffer(png_ptr, chunk_length, 4);
630 png_ptr->push_length = png_get_uint_32(chunk_length);
632 png_reset_crc(png_ptr);
633 png_crc_read(png_ptr, png_ptr->chunk_name, 4);
634 png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
636 if (png_memcmp(png_ptr->chunk_name, (png_bytep)png_IDAT, 4))
638 png_ptr->process_mode = PNG_READ_CHUNK_MODE;
639 if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
640 png_error(png_ptr, "Not enough compressed data");
644 png_ptr->idat_size = png_ptr->push_length;
646 if (png_ptr->idat_size && png_ptr->save_buffer_size)
648 png_size_t save_size;
650 if (png_ptr->idat_size < (png_uint_32)png_ptr->save_buffer_size)
652 save_size = (png_size_t)png_ptr->idat_size;
653 /* check for overflow */
654 if((png_uint_32)save_size != png_ptr->idat_size)
655 png_error(png_ptr, "save_size overflowed in pngpread");
658 save_size = png_ptr->save_buffer_size;
660 png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
661 png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size);
663 png_ptr->idat_size -= save_size;
664 png_ptr->buffer_size -= save_size;
665 png_ptr->save_buffer_size -= save_size;
666 png_ptr->save_buffer_ptr += save_size;
668 if (png_ptr->idat_size && png_ptr->current_buffer_size)
670 png_size_t save_size;
672 if (png_ptr->idat_size < (png_uint_32)png_ptr->current_buffer_size)
674 save_size = (png_size_t)png_ptr->idat_size;
675 /* check for overflow */
676 if((png_uint_32)save_size != png_ptr->idat_size)
677 png_error(png_ptr, "save_size overflowed in pngpread");
680 save_size = png_ptr->current_buffer_size;
682 png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
683 png_process_IDAT_data(png_ptr, png_ptr->current_buffer_ptr, save_size);
685 png_ptr->idat_size -= save_size;
686 png_ptr->buffer_size -= save_size;
687 png_ptr->current_buffer_size -= save_size;
688 png_ptr->current_buffer_ptr += save_size;
690 if (!png_ptr->idat_size)
692 if (png_ptr->buffer_size < 4)
694 png_push_save_buffer(png_ptr);
698 png_crc_finish(png_ptr, 0);
699 png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
704 png_process_IDAT_data(png_structp png_ptr, png_bytep buffer,
705 png_size_t buffer_length)
709 if ((png_ptr->flags & PNG_FLAG_ZLIB_FINISHED) && buffer_length)
710 png_error(png_ptr, "Extra compression data");
712 png_ptr->zstream.next_in = buffer;
713 png_ptr->zstream.avail_in = (uInt)buffer_length;
716 ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
719 if (ret == Z_STREAM_END)
721 if (png_ptr->zstream.avail_in)
722 png_error(png_ptr, "Extra compressed data");
723 if (!(png_ptr->zstream.avail_out))
725 png_push_process_row(png_ptr);
728 png_ptr->mode |= PNG_AFTER_IDAT;
729 png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
732 else if (ret == Z_BUF_ERROR)
735 png_error(png_ptr, "Decompression Error");
737 if (!(png_ptr->zstream.avail_out))
739 png_push_process_row(png_ptr);
740 png_ptr->zstream.avail_out = (uInt)png_ptr->irowbytes;
741 png_ptr->zstream.next_out = png_ptr->row_buf;
749 png_push_process_row(png_structp png_ptr)
751 png_ptr->row_info.color_type = png_ptr->color_type;
752 png_ptr->row_info.width = png_ptr->iwidth;
753 png_ptr->row_info.channels = png_ptr->channels;
754 png_ptr->row_info.bit_depth = png_ptr->bit_depth;
755 png_ptr->row_info.pixel_depth = png_ptr->pixel_depth;
757 png_ptr->row_info.rowbytes = ((png_ptr->row_info.width *
758 (png_uint_32)png_ptr->row_info.pixel_depth + 7) >> 3);
760 png_read_filter_row(png_ptr, &(png_ptr->row_info),
761 png_ptr->row_buf + 1, png_ptr->prev_row + 1,
762 (int)(png_ptr->row_buf[0]));
764 png_memcpy_check(png_ptr, png_ptr->prev_row, png_ptr->row_buf,
765 png_ptr->rowbytes + 1);
767 if (png_ptr->transformations)
768 png_do_read_transformations(png_ptr);
770 #if defined(PNG_READ_INTERLACING_SUPPORTED)
771 /* blow up interlaced rows to full size */
772 if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
774 if (png_ptr->pass < 6)
775 /* old interface (pre-1.0.9):
776 png_do_read_interlace(&(png_ptr->row_info),
777 png_ptr->row_buf + 1, png_ptr->pass, png_ptr->transformations);
779 png_do_read_interlace(png_ptr);
781 switch (png_ptr->pass)
786 for (i = 0; i < 8 && png_ptr->pass == 0; i++)
788 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
789 png_read_push_finish_row(png_ptr); /* updates png_ptr->pass */
791 if (png_ptr->pass == 2) /* pass 1 might be empty */
793 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
795 png_push_have_row(png_ptr, NULL);
796 png_read_push_finish_row(png_ptr);
804 for (i = 0; i < 8 && png_ptr->pass == 1; i++)
806 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
807 png_read_push_finish_row(png_ptr);
809 if (png_ptr->pass == 2) /* skip top 4 generated rows */
811 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
813 png_push_have_row(png_ptr, NULL);
814 png_read_push_finish_row(png_ptr);
822 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
824 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
825 png_read_push_finish_row(png_ptr);
827 for (i = 0; i < 4 && png_ptr->pass == 2; i++)
829 png_push_have_row(png_ptr, NULL);
830 png_read_push_finish_row(png_ptr);
832 if (png_ptr->pass == 4) /* pass 3 might be empty */
834 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
836 png_push_have_row(png_ptr, NULL);
837 png_read_push_finish_row(png_ptr);
845 for (i = 0; i < 4 && png_ptr->pass == 3; i++)
847 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
848 png_read_push_finish_row(png_ptr);
850 if (png_ptr->pass == 4) /* skip top two generated rows */
852 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
854 png_push_have_row(png_ptr, NULL);
855 png_read_push_finish_row(png_ptr);
863 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
865 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
866 png_read_push_finish_row(png_ptr);
868 for (i = 0; i < 2 && png_ptr->pass == 4; i++)
870 png_push_have_row(png_ptr, NULL);
871 png_read_push_finish_row(png_ptr);
873 if (png_ptr->pass == 6) /* pass 5 might be empty */
875 png_push_have_row(png_ptr, NULL);
876 png_read_push_finish_row(png_ptr);
883 for (i = 0; i < 2 && png_ptr->pass == 5; i++)
885 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
886 png_read_push_finish_row(png_ptr);
888 if (png_ptr->pass == 6) /* skip top generated row */
890 png_push_have_row(png_ptr, NULL);
891 png_read_push_finish_row(png_ptr);
897 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
898 png_read_push_finish_row(png_ptr);
899 if (png_ptr->pass != 6)
901 png_push_have_row(png_ptr, NULL);
902 png_read_push_finish_row(png_ptr);
909 png_push_have_row(png_ptr, png_ptr->row_buf + 1);
910 png_read_push_finish_row(png_ptr);
915 png_read_push_finish_row(png_structp png_ptr)
917 #ifdef PNG_USE_LOCAL_ARRAYS
918 /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
920 /* start of interlace block */
921 const int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
923 /* offset to next interlace block */
924 const int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
926 /* start of interlace block in the y direction */
927 const int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
929 /* offset to next interlace block in the y direction */
930 const int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
932 /* Width of interlace block. This is not currently used - if you need
933 * it, uncomment it here and in png.h
934 const int FARDATA png_pass_width[] = {8, 4, 4, 2, 2, 1, 1};
937 /* Height of interlace block. This is not currently used - if you need
938 * it, uncomment it here and in png.h
939 const int FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
943 png_ptr->row_number++;
944 if (png_ptr->row_number < png_ptr->num_rows)
947 if (png_ptr->interlaced)
949 png_ptr->row_number = 0;
950 png_memset_check(png_ptr, png_ptr->prev_row, 0,
951 png_ptr->rowbytes + 1);
955 if ((png_ptr->pass == 1 && png_ptr->width < 5) ||
956 (png_ptr->pass == 3 && png_ptr->width < 3) ||
957 (png_ptr->pass == 5 && png_ptr->width < 2))
960 if (png_ptr->pass >= 7)
963 png_ptr->iwidth = (png_ptr->width +
964 png_pass_inc[png_ptr->pass] - 1 -
965 png_pass_start[png_ptr->pass]) /
966 png_pass_inc[png_ptr->pass];
968 png_ptr->irowbytes = ((png_ptr->iwidth *
969 png_ptr->pixel_depth + 7) >> 3) + 1;
971 if (png_ptr->transformations & PNG_INTERLACE)
974 png_ptr->num_rows = (png_ptr->height +
975 png_pass_yinc[png_ptr->pass] - 1 -
976 png_pass_ystart[png_ptr->pass]) /
977 png_pass_yinc[png_ptr->pass];
979 } while (png_ptr->iwidth == 0 || png_ptr->num_rows == 0);
983 #if defined(PNG_READ_tEXt_SUPPORTED)
985 png_push_handle_tEXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
987 if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
989 png_error(png_ptr, "Out of place tEXt");
990 /* to quiet some compiler warnings */
991 if(info_ptr == NULL) return;
994 #ifdef PNG_MAX_MALLOC_64K
995 png_ptr->skip_length = 0; /* This may not be necessary */
997 if (length > (png_uint_32)65535L) /* Can't hold the entire string in memory */
999 png_warning(png_ptr, "tEXt chunk too large to fit in memory");
1000 png_ptr->skip_length = length - (png_uint_32)65535L;
1001 length = (png_uint_32)65535L;
1005 png_ptr->current_text = (png_charp)png_malloc(png_ptr,
1006 (png_uint_32)(length+1));
1007 png_ptr->current_text[length] = '\0';
1008 png_ptr->current_text_ptr = png_ptr->current_text;
1009 png_ptr->current_text_size = (png_size_t)length;
1010 png_ptr->current_text_left = (png_size_t)length;
1011 png_ptr->process_mode = PNG_READ_tEXt_MODE;
1015 png_push_read_tEXt(png_structp png_ptr, png_infop info_ptr)
1017 if (png_ptr->buffer_size && png_ptr->current_text_left)
1019 png_size_t text_size;
1021 if (png_ptr->buffer_size < png_ptr->current_text_left)
1022 text_size = png_ptr->buffer_size;
1024 text_size = png_ptr->current_text_left;
1025 png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
1026 png_ptr->current_text_left -= text_size;
1027 png_ptr->current_text_ptr += text_size;
1029 if (!(png_ptr->current_text_left))
1035 if (png_ptr->buffer_size < 4)
1037 png_push_save_buffer(png_ptr);
1041 png_push_crc_finish(png_ptr);
1043 #if defined(PNG_MAX_MALLOC_64K)
1044 if (png_ptr->skip_length)
1048 key = png_ptr->current_text;
1049 png_ptr->current_text = 0;
1051 for (text = key; *text; text++)
1054 if (text != key + png_ptr->current_text_size)
1057 text_ptr = (png_textp)png_malloc(png_ptr, (png_uint_32)sizeof(png_text));
1058 text_ptr->compression = PNG_TEXT_COMPRESSION_NONE;
1059 text_ptr->key = key;
1060 #ifdef PNG_iTXt_SUPPORTED
1061 text_ptr->lang = (char *)NULL;
1062 text_ptr->lang_key = (char *)NULL;
1064 text_ptr->text = text;
1066 png_set_text(png_ptr, info_ptr, text_ptr, 1);
1068 png_free(png_ptr, key);
1069 png_free(png_ptr, text_ptr);
1074 #if defined(PNG_READ_zTXt_SUPPORTED)
1076 png_push_handle_zTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
1078 if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
1080 png_error(png_ptr, "Out of place zTXt");
1081 /* to quiet some compiler warnings */
1082 if(info_ptr == NULL) return;
1085 #ifdef PNG_MAX_MALLOC_64K
1086 /* We can't handle zTXt chunks > 64K, since we don't have enough space
1087 * to be able to store the uncompressed data. Actually, the threshold
1088 * is probably around 32K, but it isn't as definite as 64K is.
1090 if (length > (png_uint_32)65535L)
1092 png_warning(png_ptr, "zTXt chunk too large to fit in memory");
1093 png_push_crc_skip(png_ptr, length);
1098 png_ptr->current_text = (png_charp)png_malloc(png_ptr,
1099 (png_uint_32)(length+1));
1100 png_ptr->current_text[length] = '\0';
1101 png_ptr->current_text_ptr = png_ptr->current_text;
1102 png_ptr->current_text_size = (png_size_t)length;
1103 png_ptr->current_text_left = (png_size_t)length;
1104 png_ptr->process_mode = PNG_READ_zTXt_MODE;
1108 png_push_read_zTXt(png_structp png_ptr, png_infop info_ptr)
1110 if (png_ptr->buffer_size && png_ptr->current_text_left)
1112 png_size_t text_size;
1114 if (png_ptr->buffer_size < (png_uint_32)png_ptr->current_text_left)
1115 text_size = png_ptr->buffer_size;
1117 text_size = png_ptr->current_text_left;
1118 png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
1119 png_ptr->current_text_left -= text_size;
1120 png_ptr->current_text_ptr += text_size;
1122 if (!(png_ptr->current_text_left))
1128 png_size_t text_size, key_size;
1130 if (png_ptr->buffer_size < 4)
1132 png_push_save_buffer(png_ptr);
1136 png_push_crc_finish(png_ptr);
1138 key = png_ptr->current_text;
1139 png_ptr->current_text = 0;
1141 for (text = key; *text; text++)
1144 /* zTXt can't have zero text */
1145 if (text == key + png_ptr->current_text_size)
1147 png_free(png_ptr, key);
1153 if (*text != PNG_TEXT_COMPRESSION_zTXt) /* check compression byte */
1155 png_free(png_ptr, key);
1161 png_ptr->zstream.next_in = (png_bytep )text;
1162 png_ptr->zstream.avail_in = (uInt)(png_ptr->current_text_size -
1164 png_ptr->zstream.next_out = png_ptr->zbuf;
1165 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
1167 key_size = text - key;
1172 while (png_ptr->zstream.avail_in)
1174 ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
1175 if (ret != Z_OK && ret != Z_STREAM_END)
1177 inflateReset(&png_ptr->zstream);
1178 png_ptr->zstream.avail_in = 0;
1179 png_free(png_ptr, key);
1180 png_free(png_ptr, text);
1183 if (!(png_ptr->zstream.avail_out) || ret == Z_STREAM_END)
1187 text = (png_charp)png_malloc(png_ptr,
1188 (png_uint_32)(png_ptr->zbuf_size - png_ptr->zstream.avail_out +
1190 png_memcpy(text + key_size, png_ptr->zbuf,
1191 png_ptr->zbuf_size - png_ptr->zstream.avail_out);
1192 png_memcpy(text, key, key_size);
1193 text_size = key_size + png_ptr->zbuf_size -
1194 png_ptr->zstream.avail_out;
1195 *(text + text_size) = '\0';
1202 text = (png_charp)png_malloc(png_ptr, text_size +
1203 (png_uint_32)(png_ptr->zbuf_size - png_ptr->zstream.avail_out
1205 png_memcpy(text, tmp, text_size);
1206 png_free(png_ptr, tmp);
1207 png_memcpy(text + text_size, png_ptr->zbuf,
1208 png_ptr->zbuf_size - png_ptr->zstream.avail_out);
1209 text_size += png_ptr->zbuf_size - png_ptr->zstream.avail_out;
1210 *(text + text_size) = '\0';
1212 if (ret != Z_STREAM_END)
1214 png_ptr->zstream.next_out = png_ptr->zbuf;
1215 png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
1223 if (ret == Z_STREAM_END)
1227 inflateReset(&png_ptr->zstream);
1228 png_ptr->zstream.avail_in = 0;
1230 if (ret != Z_STREAM_END)
1232 png_free(png_ptr, key);
1233 png_free(png_ptr, text);
1237 png_free(png_ptr, key);
1241 text_ptr = (png_textp)png_malloc(png_ptr, (png_uint_32)sizeof(png_text));
1242 text_ptr->compression = PNG_TEXT_COMPRESSION_zTXt;
1243 text_ptr->key = key;
1244 #ifdef PNG_iTXt_SUPPORTED
1245 text_ptr->lang = (char *)NULL;
1246 text_ptr->lang_key = (char *)NULL;
1248 text_ptr->text = text;
1250 png_set_text(png_ptr, info_ptr, text_ptr, 1);
1252 png_free(png_ptr, key);
1253 png_free(png_ptr, text_ptr);
1258 #if defined(PNG_READ_iTXt_SUPPORTED)
1260 png_push_handle_iTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
1262 if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
1264 png_error(png_ptr, "Out of place iTXt");
1265 /* to quiet some compiler warnings */
1266 if(info_ptr == NULL) return;
1269 #ifdef PNG_MAX_MALLOC_64K
1270 png_ptr->skip_length = 0; /* This may not be necessary */
1272 if (length > (png_uint_32)65535L) /* Can't hold the entire string in memory */
1274 png_warning(png_ptr, "iTXt chunk too large to fit in memory");
1275 png_ptr->skip_length = length - (png_uint_32)65535L;
1276 length = (png_uint_32)65535L;
1280 png_ptr->current_text = (png_charp)png_malloc(png_ptr,
1281 (png_uint_32)(length+1));
1282 png_ptr->current_text[length] = '\0';
1283 png_ptr->current_text_ptr = png_ptr->current_text;
1284 png_ptr->current_text_size = (png_size_t)length;
1285 png_ptr->current_text_left = (png_size_t)length;
1286 png_ptr->process_mode = PNG_READ_iTXt_MODE;
1290 png_push_read_iTXt(png_structp png_ptr, png_infop info_ptr)
1293 if (png_ptr->buffer_size && png_ptr->current_text_left)
1295 png_size_t text_size;
1297 if (png_ptr->buffer_size < png_ptr->current_text_left)
1298 text_size = png_ptr->buffer_size;
1300 text_size = png_ptr->current_text_left;
1301 png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
1302 png_ptr->current_text_left -= text_size;
1303 png_ptr->current_text_ptr += text_size;
1305 if (!(png_ptr->current_text_left))
1314 if (png_ptr->buffer_size < 4)
1316 png_push_save_buffer(png_ptr);
1320 png_push_crc_finish(png_ptr);
1322 #if defined(PNG_MAX_MALLOC_64K)
1323 if (png_ptr->skip_length)
1327 key = png_ptr->current_text;
1328 png_ptr->current_text = 0;
1330 for (lang = key; *lang; lang++)
1333 if (lang != key + png_ptr->current_text_size)
1336 comp_flag = *lang++;
1337 lang++; /* skip comp_type, always zero */
1339 for (lang_key = lang; *lang_key; lang_key++)
1341 lang_key++; /* skip NUL separator */
1343 for (text = lang_key; *text; text++)
1346 if (text != key + png_ptr->current_text_size)
1349 text_ptr = (png_textp)png_malloc(png_ptr, (png_uint_32)sizeof(png_text));
1350 text_ptr->compression = comp_flag + 2;
1351 text_ptr->key = key;
1352 text_ptr->lang = lang;
1353 text_ptr->lang_key = lang_key;
1354 text_ptr->text = text;
1355 text_ptr->text_length = 0;
1356 text_ptr->itxt_length = png_strlen(text);
1358 png_set_text(png_ptr, info_ptr, text_ptr, 1);
1360 png_free(png_ptr, text_ptr);
1365 /* This function is called when we haven't found a handler for this
1366 * chunk. If there isn't a problem with the chunk itself (ie a bad chunk
1367 * name or a critical chunk), the chunk is (currently) silently ignored.
1370 png_push_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
1373 png_check_chunk_name(png_ptr, png_ptr->chunk_name);
1375 if (!(png_ptr->chunk_name[0] & 0x20))
1377 #if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
1378 if(png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
1380 #if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
1381 && png_ptr->read_user_chunk_fn == (png_user_chunk_ptr)NULL
1385 png_chunk_error(png_ptr, "unknown critical chunk");
1387 /* to quiet compiler warnings about unused info_ptr */
1388 if (info_ptr == NULL)
1392 #if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
1393 if (png_ptr->flags & PNG_FLAG_KEEP_UNKNOWN_CHUNKS)
1395 png_unknown_chunk chunk;
1397 #ifdef PNG_MAX_MALLOC_64K
1398 if (length > (png_uint_32)65535L)
1400 png_warning(png_ptr, "unknown chunk too large to fit in memory");
1401 skip = length - (png_uint_32)65535L;
1402 length = (png_uint_32)65535L;
1406 strcpy((png_charp)chunk.name, (png_charp)png_ptr->chunk_name);
1407 chunk.data = (png_bytep)png_malloc(png_ptr, length);
1408 png_crc_read(png_ptr, chunk.data, length);
1409 chunk.size = length;
1410 #if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
1411 if(png_ptr->read_user_chunk_fn != (png_user_chunk_ptr)NULL)
1413 /* callback to user unknown chunk handler */
1414 if ((*(png_ptr->read_user_chunk_fn)) (png_ptr, &chunk) <= 0)
1416 if (!(png_ptr->chunk_name[0] & 0x20))
1417 if(png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
1418 HANDLE_CHUNK_ALWAYS)
1419 png_chunk_error(png_ptr, "unknown critical chunk");
1421 png_set_unknown_chunks(png_ptr, info_ptr, &chunk, 1);
1425 png_set_unknown_chunks(png_ptr, info_ptr, &chunk, 1);
1426 png_free(png_ptr, chunk.data);
1431 png_push_crc_skip(png_ptr, skip);
1435 png_push_have_info(png_structp png_ptr, png_infop info_ptr)
1437 if (png_ptr->info_fn != NULL)
1438 (*(png_ptr->info_fn))(png_ptr, info_ptr);
1442 png_push_have_end(png_structp png_ptr, png_infop info_ptr)
1444 if (png_ptr->end_fn != NULL)
1445 (*(png_ptr->end_fn))(png_ptr, info_ptr);
1449 png_push_have_row(png_structp png_ptr, png_bytep row)
1451 if (png_ptr->row_fn != NULL)
1452 (*(png_ptr->row_fn))(png_ptr, row, png_ptr->row_number,
1453 (int)png_ptr->pass);
1457 png_progressive_combine_row (png_structp png_ptr,
1458 png_bytep old_row, png_bytep new_row)
1460 #ifdef PNG_USE_LOCAL_ARRAYS
1461 const int FARDATA png_pass_dsp_mask[7] =
1462 {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
1464 if (new_row != NULL) /* new_row must == png_ptr->row_buf here. */
1465 png_combine_row(png_ptr, old_row, png_pass_dsp_mask[png_ptr->pass]);
1469 png_set_progressive_read_fn(png_structp png_ptr, png_voidp progressive_ptr,
1470 png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,
1471 png_progressive_end_ptr end_fn)
1473 png_ptr->info_fn = info_fn;
1474 png_ptr->row_fn = row_fn;
1475 png_ptr->end_fn = end_fn;
1477 png_set_read_fn(png_ptr, progressive_ptr, png_push_fill_buffer);
1481 png_get_progressive_ptr(png_structp png_ptr)
1483 return png_ptr->io_ptr;
1486 #endif /* PNG_PROGRESSIVE_READ_SUPPORTED */