1315 lines
36 KiB
C
1315 lines
36 KiB
C
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/* pngpread.c - read a png file in push mode
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*
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* Last changed in libpng 1.5.9 [February 18, 2012]
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* Copyright (c) 1998-2012 Glenn Randers-Pehrson
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* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
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* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
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*
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* This code is released under the libpng license.
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* For conditions of distribution and use, see the disclaimer
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* and license in png.h
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*/
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#include "pngpriv.h"
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#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
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/* Push model modes */
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#define PNG_READ_SIG_MODE 0
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#define PNG_READ_CHUNK_MODE 1
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#define PNG_READ_IDAT_MODE 2
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#define PNG_SKIP_MODE 3
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#define PNG_READ_tEXt_MODE 4
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#define PNG_READ_zTXt_MODE 5
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#define PNG_READ_DONE_MODE 6
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#define PNG_READ_iTXt_MODE 7
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#define PNG_ERROR_MODE 8
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void PNGAPI
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png_process_data(png_structp png_ptr, png_infop info_ptr,
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png_bytep buffer, png_size_t buffer_size)
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{
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if (png_ptr == NULL || info_ptr == NULL)
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return;
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png_push_restore_buffer(png_ptr, buffer, buffer_size);
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while (png_ptr->buffer_size)
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{
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png_process_some_data(png_ptr, info_ptr);
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}
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}
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png_size_t PNGAPI
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png_process_data_pause(png_structp png_ptr, int save)
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{
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if (png_ptr != NULL)
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{
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/* It's easiest for the caller if we do the save, then the caller doesn't
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* have to supply the same data again:
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*/
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if (save)
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png_push_save_buffer(png_ptr);
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else
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{
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/* This includes any pending saved bytes: */
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png_size_t remaining = png_ptr->buffer_size;
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png_ptr->buffer_size = 0;
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/* So subtract the saved buffer size, unless all the data
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* is actually 'saved', in which case we just return 0
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*/
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if (png_ptr->save_buffer_size < remaining)
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return remaining - png_ptr->save_buffer_size;
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}
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}
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return 0;
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}
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png_uint_32 PNGAPI
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png_process_data_skip(png_structp png_ptr)
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{
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png_uint_32 remaining = 0;
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if (png_ptr != NULL && png_ptr->process_mode == PNG_SKIP_MODE &&
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png_ptr->skip_length > 0)
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{
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/* At the end of png_process_data the buffer size must be 0 (see the loop
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* above) so we can detect a broken call here:
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*/
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if (png_ptr->buffer_size != 0)
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png_error(png_ptr,
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"png_process_data_skip called inside png_process_data");
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/* If is impossible for there to be a saved buffer at this point -
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* otherwise we could not be in SKIP mode. This will also happen if
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* png_process_skip is called inside png_process_data (but only very
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* rarely.)
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*/
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if (png_ptr->save_buffer_size != 0)
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png_error(png_ptr, "png_process_data_skip called with saved data");
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remaining = png_ptr->skip_length;
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png_ptr->skip_length = 0;
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png_ptr->process_mode = PNG_READ_CHUNK_MODE;
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}
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return remaining;
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}
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/* What we do with the incoming data depends on what we were previously
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* doing before we ran out of data...
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*/
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void /* PRIVATE */
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png_process_some_data(png_structp png_ptr, png_infop info_ptr)
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{
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if (png_ptr == NULL)
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return;
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switch (png_ptr->process_mode)
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{
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case PNG_READ_SIG_MODE:
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{
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png_push_read_sig(png_ptr, info_ptr);
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break;
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}
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case PNG_READ_CHUNK_MODE:
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{
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png_push_read_chunk(png_ptr, info_ptr);
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break;
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}
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case PNG_READ_IDAT_MODE:
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{
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png_push_read_IDAT(png_ptr);
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break;
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}
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case PNG_SKIP_MODE:
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{
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png_push_crc_finish(png_ptr);
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break;
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}
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default:
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{
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png_ptr->buffer_size = 0;
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break;
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}
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}
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}
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/* Read any remaining signature bytes from the stream and compare them with
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* the correct PNG signature. It is possible that this routine is called
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* with bytes already read from the signature, either because they have been
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* checked by the calling application, or because of multiple calls to this
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* routine.
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*/
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void /* PRIVATE */
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png_push_read_sig(png_structp png_ptr, png_infop info_ptr)
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{
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png_size_t num_checked = png_ptr->sig_bytes,
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num_to_check = 8 - num_checked;
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if (png_ptr->buffer_size < num_to_check)
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{
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num_to_check = png_ptr->buffer_size;
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}
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png_push_fill_buffer(png_ptr, &(info_ptr->signature[num_checked]),
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num_to_check);
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png_ptr->sig_bytes = (png_byte)(png_ptr->sig_bytes + num_to_check);
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if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
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{
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if (num_checked < 4 &&
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png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
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png_error(png_ptr, "Not a PNG file");
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else
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png_error(png_ptr, "PNG file corrupted by ASCII conversion");
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}
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else
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{
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if (png_ptr->sig_bytes >= 8)
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{
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png_ptr->process_mode = PNG_READ_CHUNK_MODE;
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}
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}
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}
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void /* PRIVATE */
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png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
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{
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png_uint_32 chunk_name;
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/* First we make sure we have enough data for the 4 byte chunk name
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* and the 4 byte chunk length before proceeding with decoding the
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* chunk data. To fully decode each of these chunks, we also make
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* sure we have enough data in the buffer for the 4 byte CRC at the
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* end of every chunk (except IDAT, which is handled separately).
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*/
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if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
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{
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png_byte chunk_length[4];
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png_byte chunk_tag[4];
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if (png_ptr->buffer_size < 8)
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{
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png_push_save_buffer(png_ptr);
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return;
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}
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png_push_fill_buffer(png_ptr, chunk_length, 4);
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png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
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png_reset_crc(png_ptr);
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png_crc_read(png_ptr, chunk_tag, 4);
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png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag);
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png_check_chunk_name(png_ptr, png_ptr->chunk_name);
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png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
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}
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chunk_name = png_ptr->chunk_name;
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if (chunk_name == png_IDAT)
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{
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/* This is here above the if/else case statement below because if the
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* unknown handling marks 'IDAT' as unknown then the IDAT handling case is
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* completely skipped.
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*
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* TODO: there must be a better way of doing this.
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*/
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if (png_ptr->mode & PNG_AFTER_IDAT)
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png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
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}
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if (chunk_name == png_IHDR)
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{
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if (png_ptr->push_length != 13)
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png_error(png_ptr, "Invalid IHDR length");
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if (png_ptr->push_length + 4 > png_ptr->buffer_size)
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{
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png_push_save_buffer(png_ptr);
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return;
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}
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png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length);
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}
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else if (chunk_name == png_IEND)
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{
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if (png_ptr->push_length + 4 > png_ptr->buffer_size)
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{
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png_push_save_buffer(png_ptr);
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return;
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}
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png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length);
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png_ptr->process_mode = PNG_READ_DONE_MODE;
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png_push_have_end(png_ptr, info_ptr);
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}
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#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
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else if (png_chunk_unknown_handling(png_ptr, chunk_name))
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{
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if (png_ptr->push_length + 4 > png_ptr->buffer_size)
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{
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png_push_save_buffer(png_ptr);
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return;
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}
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if (chunk_name == png_IDAT)
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png_ptr->mode |= PNG_HAVE_IDAT;
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png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length);
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if (chunk_name == png_PLTE)
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png_ptr->mode |= PNG_HAVE_PLTE;
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else if (chunk_name == png_IDAT)
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{
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if (!(png_ptr->mode & PNG_HAVE_IHDR))
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png_error(png_ptr, "Missing IHDR before IDAT");
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else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
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!(png_ptr->mode & PNG_HAVE_PLTE))
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png_error(png_ptr, "Missing PLTE before IDAT");
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}
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}
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#endif
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else if (chunk_name == png_PLTE)
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{
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if (png_ptr->push_length + 4 > png_ptr->buffer_size)
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{
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png_push_save_buffer(png_ptr);
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return;
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}
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png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
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}
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else if (chunk_name == png_IDAT)
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{
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/* If we reach an IDAT chunk, this means we have read all of the
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* header chunks, and we can start reading the image (or if this
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* is called after the image has been read - we have an error).
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*/
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if (!(png_ptr->mode & PNG_HAVE_IHDR))
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png_error(png_ptr, "Missing IHDR before IDAT");
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else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
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!(png_ptr->mode & PNG_HAVE_PLTE))
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png_error(png_ptr, "Missing PLTE before IDAT");
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if (png_ptr->mode & PNG_HAVE_IDAT)
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{
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if (!(png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
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if (png_ptr->push_length == 0)
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return;
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if (png_ptr->mode & PNG_AFTER_IDAT)
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png_benign_error(png_ptr, "Too many IDATs found");
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}
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png_ptr->idat_size = png_ptr->push_length;
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png_ptr->mode |= PNG_HAVE_IDAT;
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png_ptr->process_mode = PNG_READ_IDAT_MODE;
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png_push_have_info(png_ptr, info_ptr);
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png_ptr->zstream.avail_out =
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(uInt) PNG_ROWBYTES(png_ptr->pixel_depth,
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png_ptr->iwidth) + 1;
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png_ptr->zstream.next_out = png_ptr->row_buf;
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return;
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}
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#ifdef PNG_READ_gAMA_SUPPORTED
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else if (png_ptr->chunk_name == png_gAMA)
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{
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if (png_ptr->push_length + 4 > png_ptr->buffer_size)
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{
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png_push_save_buffer(png_ptr);
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return;
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}
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png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length);
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}
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#endif
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#ifdef PNG_READ_sBIT_SUPPORTED
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else if (png_ptr->chunk_name == png_sBIT)
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{
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if (png_ptr->push_length + 4 > png_ptr->buffer_size)
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{
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png_push_save_buffer(png_ptr);
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return;
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}
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png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length);
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}
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#endif
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#ifdef PNG_READ_cHRM_SUPPORTED
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else if (png_ptr->chunk_name == png_cHRM)
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{
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if (png_ptr->push_length + 4 > png_ptr->buffer_size)
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{
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png_push_save_buffer(png_ptr);
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return;
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}
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png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length);
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}
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#endif
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#ifdef PNG_READ_sRGB_SUPPORTED
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else if (chunk_name == png_sRGB)
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{
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if (png_ptr->push_length + 4 > png_ptr->buffer_size)
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{
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png_push_save_buffer(png_ptr);
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return;
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}
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png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length);
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}
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#endif
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#ifdef PNG_READ_iCCP_SUPPORTED
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else if (png_ptr->chunk_name == png_iCCP)
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{
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if (png_ptr->push_length + 4 > png_ptr->buffer_size)
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{
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png_push_save_buffer(png_ptr);
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return;
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}
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png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length);
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}
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#endif
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#ifdef PNG_READ_sPLT_SUPPORTED
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else if (chunk_name == png_sPLT)
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{
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if (png_ptr->push_length + 4 > png_ptr->buffer_size)
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{
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png_push_save_buffer(png_ptr);
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return;
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}
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png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length);
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}
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#endif
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#ifdef PNG_READ_tRNS_SUPPORTED
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else if (chunk_name == png_tRNS)
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{
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if (png_ptr->push_length + 4 > png_ptr->buffer_size)
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{
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png_push_save_buffer(png_ptr);
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return;
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}
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png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length);
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}
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#endif
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#ifdef PNG_READ_bKGD_SUPPORTED
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else if (chunk_name == png_bKGD)
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{
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if (png_ptr->push_length + 4 > png_ptr->buffer_size)
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{
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png_push_save_buffer(png_ptr);
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return;
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}
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png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length);
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}
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#endif
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#ifdef PNG_READ_hIST_SUPPORTED
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else if (chunk_name == png_hIST)
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{
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if (png_ptr->push_length + 4 > png_ptr->buffer_size)
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{
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png_push_save_buffer(png_ptr);
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return;
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}
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png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length);
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}
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#endif
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#ifdef PNG_READ_pHYs_SUPPORTED
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else if (chunk_name == png_pHYs)
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{
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if (png_ptr->push_length + 4 > png_ptr->buffer_size)
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{
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png_push_save_buffer(png_ptr);
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return;
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}
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png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length);
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}
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#endif
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#ifdef PNG_READ_oFFs_SUPPORTED
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else if (chunk_name == png_oFFs)
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{
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if (png_ptr->push_length + 4 > png_ptr->buffer_size)
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{
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png_push_save_buffer(png_ptr);
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return;
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}
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png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length);
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}
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#endif
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#ifdef PNG_READ_pCAL_SUPPORTED
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else if (chunk_name == png_pCAL)
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{
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if (png_ptr->push_length + 4 > png_ptr->buffer_size)
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{
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png_push_save_buffer(png_ptr);
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return;
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}
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png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length);
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}
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#endif
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#ifdef PNG_READ_sCAL_SUPPORTED
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else if (chunk_name == png_sCAL)
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{
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if (png_ptr->push_length + 4 > png_ptr->buffer_size)
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{
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png_push_save_buffer(png_ptr);
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return;
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}
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png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length);
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}
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#endif
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#ifdef PNG_READ_tIME_SUPPORTED
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else if (chunk_name == png_tIME)
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{
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if (png_ptr->push_length + 4 > png_ptr->buffer_size)
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{
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png_push_save_buffer(png_ptr);
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return;
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}
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png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length);
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}
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#endif
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#ifdef PNG_READ_tEXt_SUPPORTED
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else if (chunk_name == png_tEXt)
|
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{
|
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if (png_ptr->push_length + 4 > png_ptr->buffer_size)
|
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{
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png_push_save_buffer(png_ptr);
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return;
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}
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png_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length);
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}
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#endif
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#ifdef PNG_READ_zTXt_SUPPORTED
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else if (chunk_name == png_zTXt)
|
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{
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if (png_ptr->push_length + 4 > png_ptr->buffer_size)
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{
|
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png_push_save_buffer(png_ptr);
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return;
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}
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|
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png_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
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}
|
|
|
|
#endif
|
|
#ifdef PNG_READ_iTXt_SUPPORTED
|
|
else if (chunk_name == png_iTXt)
|
|
{
|
|
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
|
|
{
|
|
png_push_save_buffer(png_ptr);
|
|
return;
|
|
}
|
|
|
|
png_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
|
|
}
|
|
|
|
#endif
|
|
else
|
|
{
|
|
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
|
|
{
|
|
png_push_save_buffer(png_ptr);
|
|
return;
|
|
}
|
|
png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length);
|
|
}
|
|
|
|
png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
|
|
}
|
|
|
|
void /* PRIVATE */
|
|
png_push_crc_skip(png_structp png_ptr, png_uint_32 skip)
|
|
{
|
|
png_ptr->process_mode = PNG_SKIP_MODE;
|
|
png_ptr->skip_length = skip;
|
|
}
|
|
|
|
void /* PRIVATE */
|
|
png_push_crc_finish(png_structp png_ptr)
|
|
{
|
|
if (png_ptr->skip_length && png_ptr->save_buffer_size)
|
|
{
|
|
png_size_t save_size = png_ptr->save_buffer_size;
|
|
png_uint_32 skip_length = png_ptr->skip_length;
|
|
|
|
/* We want the smaller of 'skip_length' and 'save_buffer_size', but
|
|
* they are of different types and we don't know which variable has the
|
|
* fewest bits. Carefully select the smaller and cast it to the type of
|
|
* the larger - this cannot overflow. Do not cast in the following test
|
|
* - it will break on either 16 or 64 bit platforms.
|
|
*/
|
|
if (skip_length < save_size)
|
|
save_size = (png_size_t)skip_length;
|
|
|
|
else
|
|
skip_length = (png_uint_32)save_size;
|
|
|
|
png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
|
|
|
|
png_ptr->skip_length -= skip_length;
|
|
png_ptr->buffer_size -= save_size;
|
|
png_ptr->save_buffer_size -= save_size;
|
|
png_ptr->save_buffer_ptr += save_size;
|
|
}
|
|
|
|
if (png_ptr->skip_length && png_ptr->current_buffer_size)
|
|
{
|
|
png_size_t save_size = png_ptr->current_buffer_size;
|
|
png_uint_32 skip_length = png_ptr->skip_length;
|
|
|
|
/* We want the smaller of 'skip_length' and 'current_buffer_size', here,
|
|
* the same problem exists as above and the same solution.
|
|
*/
|
|
if (skip_length < save_size)
|
|
save_size = (png_size_t)skip_length;
|
|
|
|
else
|
|
skip_length = (png_uint_32)save_size;
|
|
|
|
png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
|
|
|
|
png_ptr->skip_length -= skip_length;
|
|
png_ptr->buffer_size -= save_size;
|
|
png_ptr->current_buffer_size -= save_size;
|
|
png_ptr->current_buffer_ptr += save_size;
|
|
}
|
|
|
|
if (!png_ptr->skip_length)
|
|
{
|
|
if (png_ptr->buffer_size < 4)
|
|
{
|
|
png_push_save_buffer(png_ptr);
|
|
return;
|
|
}
|
|
|
|
png_crc_finish(png_ptr, 0);
|
|
png_ptr->process_mode = PNG_READ_CHUNK_MODE;
|
|
}
|
|
}
|
|
|
|
void PNGCBAPI
|
|
png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
|
|
{
|
|
png_bytep ptr;
|
|
|
|
if (png_ptr == NULL)
|
|
return;
|
|
|
|
ptr = buffer;
|
|
|
|
if (png_ptr->save_buffer_size)
|
|
{
|
|
png_size_t save_size;
|
|
|
|
if (length < png_ptr->save_buffer_size)
|
|
save_size = length;
|
|
|
|
else
|
|
save_size = png_ptr->save_buffer_size;
|
|
|
|
png_memcpy(ptr, png_ptr->save_buffer_ptr, save_size);
|
|
length -= save_size;
|
|
ptr += save_size;
|
|
png_ptr->buffer_size -= save_size;
|
|
png_ptr->save_buffer_size -= save_size;
|
|
png_ptr->save_buffer_ptr += save_size;
|
|
}
|
|
|
|
if (length && png_ptr->current_buffer_size)
|
|
{
|
|
png_size_t save_size;
|
|
|
|
if (length < png_ptr->current_buffer_size)
|
|
save_size = length;
|
|
|
|
else
|
|
save_size = png_ptr->current_buffer_size;
|
|
|
|
png_memcpy(ptr, png_ptr->current_buffer_ptr, save_size);
|
|
png_ptr->buffer_size -= save_size;
|
|
png_ptr->current_buffer_size -= save_size;
|
|
png_ptr->current_buffer_ptr += save_size;
|
|
}
|
|
}
|
|
|
|
void /* PRIVATE */
|
|
png_push_save_buffer(png_structp png_ptr)
|
|
{
|
|
if (png_ptr->save_buffer_size)
|
|
{
|
|
if (png_ptr->save_buffer_ptr != png_ptr->save_buffer)
|
|
{
|
|
png_size_t i, istop;
|
|
png_bytep sp;
|
|
png_bytep dp;
|
|
|
|
istop = png_ptr->save_buffer_size;
|
|
|
|
for (i = 0, sp = png_ptr->save_buffer_ptr, dp = png_ptr->save_buffer;
|
|
i < istop; i++, sp++, dp++)
|
|
{
|
|
*dp = *sp;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (png_ptr->save_buffer_size + png_ptr->current_buffer_size >
|
|
png_ptr->save_buffer_max)
|
|
{
|
|
png_size_t new_max;
|
|
png_bytep old_buffer;
|
|
|
|
if (png_ptr->save_buffer_size > PNG_SIZE_MAX -
|
|
(png_ptr->current_buffer_size + 256))
|
|
{
|
|
png_error(png_ptr, "Potential overflow of save_buffer");
|
|
}
|
|
|
|
new_max = png_ptr->save_buffer_size + png_ptr->current_buffer_size + 256;
|
|
old_buffer = png_ptr->save_buffer;
|
|
png_ptr->save_buffer = (png_bytep)png_malloc_warn(png_ptr, new_max);
|
|
|
|
if (png_ptr->save_buffer == NULL)
|
|
{
|
|
png_free(png_ptr, old_buffer);
|
|
png_error(png_ptr, "Insufficient memory for save_buffer");
|
|
}
|
|
|
|
png_memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size);
|
|
png_free(png_ptr, old_buffer);
|
|
png_ptr->save_buffer_max = new_max;
|
|
}
|
|
|
|
if (png_ptr->current_buffer_size)
|
|
{
|
|
png_memcpy(png_ptr->save_buffer + png_ptr->save_buffer_size,
|
|
png_ptr->current_buffer_ptr, png_ptr->current_buffer_size);
|
|
png_ptr->save_buffer_size += png_ptr->current_buffer_size;
|
|
png_ptr->current_buffer_size = 0;
|
|
}
|
|
|
|
png_ptr->save_buffer_ptr = png_ptr->save_buffer;
|
|
png_ptr->buffer_size = 0;
|
|
}
|
|
|
|
void /* PRIVATE */
|
|
png_push_restore_buffer(png_structp png_ptr, png_bytep buffer,
|
|
png_size_t buffer_length)
|
|
{
|
|
png_ptr->current_buffer = buffer;
|
|
png_ptr->current_buffer_size = buffer_length;
|
|
png_ptr->buffer_size = buffer_length + png_ptr->save_buffer_size;
|
|
png_ptr->current_buffer_ptr = png_ptr->current_buffer;
|
|
}
|
|
|
|
void /* PRIVATE */
|
|
png_push_read_IDAT(png_structp png_ptr)
|
|
{
|
|
if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
|
|
{
|
|
png_byte chunk_length[4];
|
|
png_byte chunk_tag[4];
|
|
|
|
/* TODO: this code can be commoned up with the same code in push_read */
|
|
if (png_ptr->buffer_size < 8)
|
|
{
|
|
png_push_save_buffer(png_ptr);
|
|
return;
|
|
}
|
|
|
|
png_push_fill_buffer(png_ptr, chunk_length, 4);
|
|
png_ptr->push_length = png_get_uint_31(png_ptr, chunk_length);
|
|
png_reset_crc(png_ptr);
|
|
png_crc_read(png_ptr, chunk_tag, 4);
|
|
png_ptr->chunk_name = PNG_CHUNK_FROM_STRING(chunk_tag);
|
|
png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
|
|
|
|
if (png_ptr->chunk_name != png_IDAT)
|
|
{
|
|
png_ptr->process_mode = PNG_READ_CHUNK_MODE;
|
|
|
|
if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
|
|
png_error(png_ptr, "Not enough compressed data");
|
|
|
|
return;
|
|
}
|
|
|
|
png_ptr->idat_size = png_ptr->push_length;
|
|
}
|
|
|
|
if (png_ptr->idat_size && png_ptr->save_buffer_size)
|
|
{
|
|
png_size_t save_size = png_ptr->save_buffer_size;
|
|
png_uint_32 idat_size = png_ptr->idat_size;
|
|
|
|
/* We want the smaller of 'idat_size' and 'current_buffer_size', but they
|
|
* are of different types and we don't know which variable has the fewest
|
|
* bits. Carefully select the smaller and cast it to the type of the
|
|
* larger - this cannot overflow. Do not cast in the following test - it
|
|
* will break on either 16 or 64 bit platforms.
|
|
*/
|
|
if (idat_size < save_size)
|
|
save_size = (png_size_t)idat_size;
|
|
|
|
else
|
|
idat_size = (png_uint_32)save_size;
|
|
|
|
png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
|
|
|
|
png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size);
|
|
|
|
png_ptr->idat_size -= idat_size;
|
|
png_ptr->buffer_size -= save_size;
|
|
png_ptr->save_buffer_size -= save_size;
|
|
png_ptr->save_buffer_ptr += save_size;
|
|
}
|
|
|
|
if (png_ptr->idat_size && png_ptr->current_buffer_size)
|
|
{
|
|
png_size_t save_size = png_ptr->current_buffer_size;
|
|
png_uint_32 idat_size = png_ptr->idat_size;
|
|
|
|
/* We want the smaller of 'idat_size' and 'current_buffer_size', but they
|
|
* are of different types and we don't know which variable has the fewest
|
|
* bits. Carefully select the smaller and cast it to the type of the
|
|
* larger - this cannot overflow.
|
|
*/
|
|
if (idat_size < save_size)
|
|
save_size = (png_size_t)idat_size;
|
|
|
|
else
|
|
idat_size = (png_uint_32)save_size;
|
|
|
|
png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
|
|
|
|
png_process_IDAT_data(png_ptr, png_ptr->current_buffer_ptr, save_size);
|
|
|
|
png_ptr->idat_size -= idat_size;
|
|
png_ptr->buffer_size -= save_size;
|
|
png_ptr->current_buffer_size -= save_size;
|
|
png_ptr->current_buffer_ptr += save_size;
|
|
}
|
|
|
|
if (!png_ptr->idat_size)
|
|
{
|
|
if (png_ptr->buffer_size < 4)
|
|
{
|
|
png_push_save_buffer(png_ptr);
|
|
return;
|
|
}
|
|
|
|
png_crc_finish(png_ptr, 0);
|
|
png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
|
|
png_ptr->mode |= PNG_AFTER_IDAT;
|
|
}
|
|
}
|
|
|
|
void /* PRIVATE */
|
|
png_process_IDAT_data(png_structp png_ptr, png_bytep buffer,
|
|
png_size_t buffer_length)
|
|
{
|
|
/* The caller checks for a non-zero buffer length. */
|
|
if (!(buffer_length > 0) || buffer == NULL)
|
|
png_error(png_ptr, "No IDAT data (internal error)");
|
|
|
|
/* This routine must process all the data it has been given
|
|
* before returning, calling the row callback as required to
|
|
* handle the uncompressed results.
|
|
*/
|
|
png_ptr->zstream.next_in = buffer;
|
|
png_ptr->zstream.avail_in = (uInt)buffer_length;
|
|
|
|
/* Keep going until the decompressed data is all processed
|
|
* or the stream marked as finished.
|
|
*/
|
|
while (png_ptr->zstream.avail_in > 0 &&
|
|
!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
|
|
{
|
|
int ret;
|
|
|
|
/* We have data for zlib, but we must check that zlib
|
|
* has someplace to put the results. It doesn't matter
|
|
* if we don't expect any results -- it may be the input
|
|
* data is just the LZ end code.
|
|
*/
|
|
if (!(png_ptr->zstream.avail_out > 0))
|
|
{
|
|
png_ptr->zstream.avail_out =
|
|
(uInt) PNG_ROWBYTES(png_ptr->pixel_depth,
|
|
png_ptr->iwidth) + 1;
|
|
|
|
png_ptr->zstream.next_out = png_ptr->row_buf;
|
|
}
|
|
|
|
/* Using Z_SYNC_FLUSH here means that an unterminated
|
|
* LZ stream (a stream with a missing end code) can still
|
|
* be handled, otherwise (Z_NO_FLUSH) a future zlib
|
|
* implementation might defer output and therefore
|
|
* change the current behavior (see comments in inflate.c
|
|
* for why this doesn't happen at present with zlib 1.2.5).
|
|
*/
|
|
ret = inflate(&png_ptr->zstream, Z_SYNC_FLUSH);
|
|
|
|
/* Check for any failure before proceeding. */
|
|
if (ret != Z_OK && ret != Z_STREAM_END)
|
|
{
|
|
/* Terminate the decompression. */
|
|
png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
|
|
|
|
/* This may be a truncated stream (missing or
|
|
* damaged end code). Treat that as a warning.
|
|
*/
|
|
if (png_ptr->row_number >= png_ptr->num_rows ||
|
|
png_ptr->pass > 6)
|
|
png_warning(png_ptr, "Truncated compressed data in IDAT");
|
|
|
|
else
|
|
png_error(png_ptr, "Decompression error in IDAT");
|
|
|
|
/* Skip the check on unprocessed input */
|
|
return;
|
|
}
|
|
|
|
/* Did inflate output any data? */
|
|
if (png_ptr->zstream.next_out != png_ptr->row_buf)
|
|
{
|
|
/* Is this unexpected data after the last row?
|
|
* If it is, artificially terminate the LZ output
|
|
* here.
|
|
*/
|
|
if (png_ptr->row_number >= png_ptr->num_rows ||
|
|
png_ptr->pass > 6)
|
|
{
|
|
/* Extra data. */
|
|
png_warning(png_ptr, "Extra compressed data in IDAT");
|
|
png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
|
|
|
|
/* Do no more processing; skip the unprocessed
|
|
* input check below.
|
|
*/
|
|
return;
|
|
}
|
|
|
|
/* Do we have a complete row? */
|
|
if (png_ptr->zstream.avail_out == 0)
|
|
png_push_process_row(png_ptr);
|
|
}
|
|
|
|
/* And check for the end of the stream. */
|
|
if (ret == Z_STREAM_END)
|
|
png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
|
|
}
|
|
|
|
/* All the data should have been processed, if anything
|
|
* is left at this point we have bytes of IDAT data
|
|
* after the zlib end code.
|
|
*/
|
|
if (png_ptr->zstream.avail_in > 0)
|
|
png_warning(png_ptr, "Extra compression data in IDAT");
|
|
}
|
|
|
|
void /* PRIVATE */
|
|
png_push_process_row(png_structp png_ptr)
|
|
{
|
|
/* 1.5.6: row_info moved out of png_struct to a local here. */
|
|
png_row_info row_info;
|
|
|
|
row_info.width = png_ptr->iwidth; /* NOTE: width of current interlaced row */
|
|
row_info.color_type = png_ptr->color_type;
|
|
row_info.bit_depth = png_ptr->bit_depth;
|
|
row_info.channels = png_ptr->channels;
|
|
row_info.pixel_depth = png_ptr->pixel_depth;
|
|
row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
|
|
|
|
if (png_ptr->row_buf[0] > PNG_FILTER_VALUE_NONE)
|
|
{
|
|
if (png_ptr->row_buf[0] < PNG_FILTER_VALUE_LAST)
|
|
png_read_filter_row(png_ptr, &row_info, png_ptr->row_buf + 1,
|
|
png_ptr->prev_row + 1, png_ptr->row_buf[0]);
|
|
else
|
|
png_error(png_ptr, "bad adaptive filter value");
|
|
}
|
|
|
|
/* libpng 1.5.6: the following line was copying png_ptr->rowbytes before
|
|
* 1.5.6, while the buffer really is this big in current versions of libpng
|
|
* it may not be in the future, so this was changed just to copy the
|
|
* interlaced row count:
|
|
*/
|
|
png_memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1);
|
|
|
|
#ifdef PNG_READ_TRANSFORMS_SUPPORTED
|
|
if (png_ptr->transformations)
|
|
png_do_read_transformations(png_ptr, &row_info);
|
|
#endif
|
|
|
|
/* The transformed pixel depth should match the depth now in row_info. */
|
|
if (png_ptr->transformed_pixel_depth == 0)
|
|
{
|
|
png_ptr->transformed_pixel_depth = row_info.pixel_depth;
|
|
if (row_info.pixel_depth > png_ptr->maximum_pixel_depth)
|
|
png_error(png_ptr, "progressive row overflow");
|
|
}
|
|
|
|
else if (png_ptr->transformed_pixel_depth != row_info.pixel_depth)
|
|
png_error(png_ptr, "internal progressive row size calculation error");
|
|
|
|
|
|
#ifdef PNG_READ_INTERLACING_SUPPORTED
|
|
/* Blow up interlaced rows to full size */
|
|
if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
|
|
{
|
|
if (png_ptr->pass < 6)
|
|
png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass,
|
|
png_ptr->transformations);
|
|
|
|
switch (png_ptr->pass)
|
|
{
|
|
case 0:
|
|
{
|
|
int i;
|
|
for (i = 0; i < 8 && png_ptr->pass == 0; i++)
|
|
{
|
|
png_push_have_row(png_ptr, png_ptr->row_buf + 1);
|
|
png_read_push_finish_row(png_ptr); /* Updates png_ptr->pass */
|
|
}
|
|
|
|
if (png_ptr->pass == 2) /* Pass 1 might be empty */
|
|
{
|
|
for (i = 0; i < 4 && png_ptr->pass == 2; i++)
|
|
{
|
|
png_push_have_row(png_ptr, NULL);
|
|
png_read_push_finish_row(png_ptr);
|
|
}
|
|
}
|
|
|
|
if (png_ptr->pass == 4 && png_ptr->height <= 4)
|
|
{
|
|
for (i = 0; i < 2 && png_ptr->pass == 4; i++)
|
|
{
|
|
png_push_have_row(png_ptr, NULL);
|
|
png_read_push_finish_row(png_ptr);
|
|
}
|
|
}
|
|
|
|
if (png_ptr->pass == 6 && png_ptr->height <= 4)
|
|
{
|
|
png_push_have_row(png_ptr, NULL);
|
|
png_read_push_finish_row(png_ptr);
|
|
}
|
|
|
|
break;
|
|
}
|
|
|
|
case 1:
|
|
{
|
|
int i;
|
|
for (i = 0; i < 8 && png_ptr->pass == 1; i++)
|
|
{
|
|
png_push_have_row(png_ptr, png_ptr->row_buf + 1);
|
|
png_read_push_finish_row(png_ptr);
|
|
}
|
|
|
|
if (png_ptr->pass == 2) /* Skip top 4 generated rows */
|
|
{
|
|
for (i = 0; i < 4 && png_ptr->pass == 2; i++)
|
|
{
|
|
png_push_have_row(png_ptr, NULL);
|
|
png_read_push_finish_row(png_ptr);
|
|
}
|
|
}
|
|
|
|
break;
|
|
}
|
|
|
|
case 2:
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < 4 && png_ptr->pass == 2; i++)
|
|
{
|
|
png_push_have_row(png_ptr, png_ptr->row_buf + 1);
|
|
png_read_push_finish_row(png_ptr);
|
|
}
|
|
|
|
for (i = 0; i < 4 && png_ptr->pass == 2; i++)
|
|
{
|
|
png_push_have_row(png_ptr, NULL);
|
|
png_read_push_finish_row(png_ptr);
|
|
}
|
|
|
|
if (png_ptr->pass == 4) /* Pass 3 might be empty */
|
|
{
|
|
for (i = 0; i < 2 && png_ptr->pass == 4; i++)
|
|
{
|
|
png_push_have_row(png_ptr, NULL);
|
|
png_read_push_finish_row(png_ptr);
|
|
}
|
|
}
|
|
|
|
break;
|
|
}
|
|
|
|
case 3:
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < 4 && png_ptr->pass == 3; i++)
|
|
{
|
|
png_push_have_row(png_ptr, png_ptr->row_buf + 1);
|
|
png_read_push_finish_row(png_ptr);
|
|
}
|
|
|
|
if (png_ptr->pass == 4) /* Skip top two generated rows */
|
|
{
|
|
for (i = 0; i < 2 && png_ptr->pass == 4; i++)
|
|
{
|
|
png_push_have_row(png_ptr, NULL);
|
|
png_read_push_finish_row(png_ptr);
|
|
}
|
|
}
|
|
|
|
break;
|
|
}
|
|
|
|
case 4:
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < 2 && png_ptr->pass == 4; i++)
|
|
{
|
|
png_push_have_row(png_ptr, png_ptr->row_buf + 1);
|
|
png_read_push_finish_row(png_ptr);
|
|
}
|
|
|
|
for (i = 0; i < 2 && png_ptr->pass == 4; i++)
|
|
{
|
|
png_push_have_row(png_ptr, NULL);
|
|
png_read_push_finish_row(png_ptr);
|
|
}
|
|
|
|
if (png_ptr->pass == 6) /* Pass 5 might be empty */
|
|
{
|
|
png_push_have_row(png_ptr, NULL);
|
|
png_read_push_finish_row(png_ptr);
|
|
}
|
|
|
|
break;
|
|
}
|
|
|
|
case 5:
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < 2 && png_ptr->pass == 5; i++)
|
|
{
|
|
png_push_have_row(png_ptr, png_ptr->row_buf + 1);
|
|
png_read_push_finish_row(png_ptr);
|
|
}
|
|
|
|
if (png_ptr->pass == 6) /* Skip top generated row */
|
|
{
|
|
png_push_have_row(png_ptr, NULL);
|
|
png_read_push_finish_row(png_ptr);
|
|
}
|
|
|
|
break;
|
|
}
|
|
|
|
default:
|
|
case 6:
|
|
{
|
|
png_push_have_row(png_ptr, png_ptr->row_buf + 1);
|
|
png_read_push_finish_row(png_ptr);
|
|
|
|
if (png_ptr->pass != 6)
|
|
break;
|
|
|
|
png_push_have_row(png_ptr, NULL);
|
|
png_read_push_finish_row(png_ptr);
|
|
}
|
|
}
|
|
}
|
|
else
|
|
#endif
|
|
{
|
|
png_push_have_row(png_ptr, png_ptr->row_buf + 1);
|
|
png_read_push_finish_row(png_ptr);
|
|
}
|
|
}
|
|
|
|
void /* PRIVATE */
|
|
png_read_push_finish_row(png_structp png_ptr)
|
|
{
|
|
#ifdef PNG_READ_INTERLACING_SUPPORTED
|
|
/* Arrays to facilitate easy interlacing - use pass (0 - 6) as index */
|
|
|
|
/* Start of interlace block */
|
|
static PNG_CONST png_byte FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
|
|
|
|
/* Offset to next interlace block */
|
|
static PNG_CONST png_byte FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
|
|
|
|
/* Start of interlace block in the y direction */
|
|
static PNG_CONST png_byte FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
|
|
|
|
/* Offset to next interlace block in the y direction */
|
|
static PNG_CONST png_byte FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
|
|
|
|
/* Height of interlace block. This is not currently used - if you need
|
|
* it, uncomment it here and in png.h
|
|
static PNG_CONST png_byte FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
|
|
*/
|
|
#endif
|
|
|
|
png_ptr->row_number++;
|
|
if (png_ptr->row_number < png_ptr->num_rows)
|
|
return;
|
|
|
|
#ifdef PNG_READ_INTERLACING_SUPPORTED
|
|
if (png_ptr->interlaced)
|
|
{
|
|
png_ptr->row_number = 0;
|
|
png_memset(png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
|
|
|
|
do
|
|
{
|
|
png_ptr->pass++;
|
|
if ((png_ptr->pass == 1 && png_ptr->width < 5) ||
|
|
(png_ptr->pass == 3 && png_ptr->width < 3) ||
|
|
(png_ptr->pass == 5 && png_ptr->width < 2))
|
|
png_ptr->pass++;
|
|
|
|
if (png_ptr->pass > 7)
|
|
png_ptr->pass--;
|
|
|
|
if (png_ptr->pass >= 7)
|
|
break;
|
|
|
|
png_ptr->iwidth = (png_ptr->width +
|
|
png_pass_inc[png_ptr->pass] - 1 -
|
|
png_pass_start[png_ptr->pass]) /
|
|
png_pass_inc[png_ptr->pass];
|
|
|
|
if (png_ptr->transformations & PNG_INTERLACE)
|
|
break;
|
|
|
|
png_ptr->num_rows = (png_ptr->height +
|
|
png_pass_yinc[png_ptr->pass] - 1 -
|
|
png_pass_ystart[png_ptr->pass]) /
|
|
png_pass_yinc[png_ptr->pass];
|
|
|
|
} while (png_ptr->iwidth == 0 || png_ptr->num_rows == 0);
|
|
}
|
|
#endif /* PNG_READ_INTERLACING_SUPPORTED */
|
|
}
|
|
|
|
void /* PRIVATE */
|
|
png_push_have_info(png_structp png_ptr, png_infop info_ptr)
|
|
{
|
|
if (png_ptr->info_fn != NULL)
|
|
(*(png_ptr->info_fn))(png_ptr, info_ptr);
|
|
}
|
|
|
|
void /* PRIVATE */
|
|
png_push_have_end(png_structp png_ptr, png_infop info_ptr)
|
|
{
|
|
if (png_ptr->end_fn != NULL)
|
|
(*(png_ptr->end_fn))(png_ptr, info_ptr);
|
|
}
|
|
|
|
void /* PRIVATE */
|
|
png_push_have_row(png_structp png_ptr, png_bytep row)
|
|
{
|
|
if (png_ptr->row_fn != NULL)
|
|
(*(png_ptr->row_fn))(png_ptr, row, png_ptr->row_number,
|
|
(int)png_ptr->pass);
|
|
}
|
|
|
|
#ifdef PNG_READ_INTERLACING_SUPPORTED
|
|
void PNGAPI
|
|
png_progressive_combine_row (png_structp png_ptr, png_bytep old_row,
|
|
png_const_bytep new_row)
|
|
{
|
|
if (png_ptr == NULL)
|
|
return;
|
|
|
|
/* new_row is a flag here - if it is NULL then the app callback was called
|
|
* from an empty row (see the calls to png_struct::row_fn below), otherwise
|
|
* it must be png_ptr->row_buf+1
|
|
*/
|
|
if (new_row != NULL)
|
|
png_combine_row(png_ptr, old_row, 1/*display*/);
|
|
}
|
|
#endif /* PNG_READ_INTERLACING_SUPPORTED */
|
|
|
|
void PNGAPI
|
|
png_set_progressive_read_fn(png_structp png_ptr, png_voidp progressive_ptr,
|
|
png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,
|
|
png_progressive_end_ptr end_fn)
|
|
{
|
|
if (png_ptr == NULL)
|
|
return;
|
|
|
|
png_ptr->info_fn = info_fn;
|
|
png_ptr->row_fn = row_fn;
|
|
png_ptr->end_fn = end_fn;
|
|
|
|
png_set_read_fn(png_ptr, progressive_ptr, png_push_fill_buffer);
|
|
}
|
|
|
|
png_voidp PNGAPI
|
|
png_get_progressive_ptr(png_const_structp png_ptr)
|
|
{
|
|
if (png_ptr == NULL)
|
|
return (NULL);
|
|
|
|
return png_ptr->io_ptr;
|
|
}
|
|
#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
|