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libpng/pngpread.c

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/* pngpread.c - read a png file in push mode
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*
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* libpng version 1.2.6rc2 - August 8, 2004
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* For conditions of distribution and use, see copyright notice in png.h
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* Copyright (c) 1998-2004 Glenn Randers-Pehrson
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* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
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*/
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#define PNG_INTERNAL
#include "png.h"
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#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
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/* push model modes */
#define PNG_READ_SIG_MODE 0
#define PNG_READ_CHUNK_MODE 1
#define PNG_READ_IDAT_MODE 2
#define PNG_SKIP_MODE 3
#define PNG_READ_tEXt_MODE 4
#define PNG_READ_zTXt_MODE 5
#define PNG_READ_DONE_MODE 6
#define PNG_READ_iTXt_MODE 7
#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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png_push_restore_buffer(png_ptr, buffer, buffer_size);
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while (png_ptr->buffer_size)
{
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png_process_some_data(png_ptr, info_ptr);
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}
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}
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/* What we do with the incoming data depends on what we were previously
* doing before we ran out of data...
*/
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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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switch (png_ptr->process_mode)
{
case PNG_READ_SIG_MODE:
{
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png_push_read_sig(png_ptr, info_ptr);
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break;
}
case PNG_READ_CHUNK_MODE:
{
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png_push_read_chunk(png_ptr, info_ptr);
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break;
}
case PNG_READ_IDAT_MODE:
{
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png_push_read_IDAT(png_ptr);
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break;
}
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#if defined(PNG_READ_tEXt_SUPPORTED)
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case PNG_READ_tEXt_MODE:
{
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png_push_read_tEXt(png_ptr, info_ptr);
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break;
}
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#endif
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#if defined(PNG_READ_zTXt_SUPPORTED)
case PNG_READ_zTXt_MODE:
{
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png_push_read_zTXt(png_ptr, info_ptr);
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break;
}
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#endif
#if defined(PNG_READ_iTXt_SUPPORTED)
case PNG_READ_iTXt_MODE:
{
png_push_read_iTXt(png_ptr, info_ptr);
break;
}
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#endif
case PNG_SKIP_MODE:
{
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png_push_crc_finish(png_ptr);
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break;
}
default:
{
png_ptr->buffer_size = 0;
break;
}
}
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}
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/* Read any remaining signature bytes from the stream and compare them with
* 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
* checked by the calling application, or because of multiple calls to this
* 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,
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 &&
png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
png_error(png_ptr, "Not a PNG file");
else
png_error(png_ptr, "PNG file corrupted by ASCII conversion");
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}
else
{
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if (png_ptr->sig_bytes >= 8)
{
png_ptr->process_mode = PNG_READ_CHUNK_MODE;
}
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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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#ifdef PNG_USE_LOCAL_ARRAYS
PNG_IHDR;
PNG_IDAT;
PNG_IEND;
PNG_PLTE;
#if defined(PNG_READ_bKGD_SUPPORTED)
PNG_bKGD;
#endif
#if defined(PNG_READ_cHRM_SUPPORTED)
PNG_cHRM;
#endif
#if defined(PNG_READ_gAMA_SUPPORTED)
PNG_gAMA;
#endif
#if defined(PNG_READ_hIST_SUPPORTED)
PNG_hIST;
#endif
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#if defined(PNG_READ_iCCP_SUPPORTED)
PNG_iCCP;
#endif
#if defined(PNG_READ_iTXt_SUPPORTED)
PNG_iTXt;
#endif
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#if defined(PNG_READ_oFFs_SUPPORTED)
PNG_oFFs;
#endif
#if defined(PNG_READ_pCAL_SUPPORTED)
PNG_pCAL;
#endif
#if defined(PNG_READ_pHYs_SUPPORTED)
PNG_pHYs;
#endif
#if defined(PNG_READ_sBIT_SUPPORTED)
PNG_sBIT;
#endif
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#if defined(PNG_READ_sCAL_SUPPORTED)
PNG_sCAL;
#endif
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#if defined(PNG_READ_sRGB_SUPPORTED)
PNG_sRGB;
#endif
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#if defined(PNG_READ_sPLT_SUPPORTED)
PNG_sPLT;
#endif
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#if defined(PNG_READ_tEXt_SUPPORTED)
PNG_tEXt;
#endif
#if defined(PNG_READ_tIME_SUPPORTED)
PNG_tIME;
#endif
#if defined(PNG_READ_tRNS_SUPPORTED)
PNG_tRNS;
#endif
#if defined(PNG_READ_zTXt_SUPPORTED)
PNG_zTXt;
#endif
#endif /* PNG_USE_LOCAL_ARRAYS */
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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
* chunk data. To fully decode each of these chunks, we also make
* sure we have enough data in the buffer for the 4 byte CRC at the
* end of every chunk (except IDAT, which is handled separately).
*/
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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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if (png_ptr->buffer_size < 8)
{
png_push_save_buffer(png_ptr);
return;
}
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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, png_ptr->chunk_name, 4);
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png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
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}
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if (!png_memcmp(png_ptr->chunk_name, png_IHDR, 4))
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{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
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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 (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
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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);
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 (!png_memcmp(png_ptr->chunk_name, (png_bytep)png_IDAT, 4))
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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
* is called after the image has been read - we have an error).
*/
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if (!(png_ptr->mode & PNG_HAVE_IHDR))
png_error(png_ptr, "Missing IHDR before IDAT");
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)
{
if (png_ptr->push_length == 0)
return;
if (png_ptr->mode & PNG_AFTER_IDAT)
png_error(png_ptr, "Too many IDAT's found");
}
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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);
png_ptr->zstream.avail_out = (uInt)png_ptr->irowbytes;
png_ptr->zstream.next_out = png_ptr->row_buf;
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return;
}
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else if (!png_memcmp(png_ptr->chunk_name, png_IEND, 4))
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{
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if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length);
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png_ptr->process_mode = PNG_READ_DONE_MODE;
png_push_have_end(png_ptr, info_ptr);
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}
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#if defined(PNG_READ_gAMA_SUPPORTED)
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else if (!png_memcmp(png_ptr->chunk_name, png_gAMA, 4))
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{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
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png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length);
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}
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#endif
#if defined(PNG_READ_sBIT_SUPPORTED)
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else if (!png_memcmp(png_ptr->chunk_name, png_sBIT, 4))
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{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
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png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length);
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}
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#endif
#if defined(PNG_READ_cHRM_SUPPORTED)
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else if (!png_memcmp(png_ptr->chunk_name, png_cHRM, 4))
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{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
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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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#if defined(PNG_READ_sRGB_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_sRGB, 4))
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length);
}
#endif
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#if defined(PNG_READ_iCCP_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_iCCP, 4))
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length);
}
#endif
#if defined(PNG_READ_sPLT_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_sPLT, 4))
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length);
}
#endif
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#if defined(PNG_READ_tRNS_SUPPORTED)
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else if (!png_memcmp(png_ptr->chunk_name, png_tRNS, 4))
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{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
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png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length);
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}
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#endif
#if defined(PNG_READ_bKGD_SUPPORTED)
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else if (!png_memcmp(png_ptr->chunk_name, png_bKGD, 4))
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{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
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png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length);
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}
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#endif
#if defined(PNG_READ_hIST_SUPPORTED)
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else if (!png_memcmp(png_ptr->chunk_name, png_hIST, 4))
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{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
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png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length);
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}
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#endif
#if defined(PNG_READ_pHYs_SUPPORTED)
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else if (!png_memcmp(png_ptr->chunk_name, png_pHYs, 4))
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{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
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png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length);
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}
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#endif
#if defined(PNG_READ_oFFs_SUPPORTED)
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else if (!png_memcmp(png_ptr->chunk_name, png_oFFs, 4))
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{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
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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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#if defined(PNG_READ_pCAL_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_pCAL, 4))
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length);
}
#endif
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#if defined(PNG_READ_sCAL_SUPPORTED)
else if (!png_memcmp(png_ptr->chunk_name, png_sCAL, 4))
{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length);
}
#endif
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#if defined(PNG_READ_tIME_SUPPORTED)
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else if (!png_memcmp(png_ptr->chunk_name, png_tIME, 4))
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{
if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
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png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length);
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}
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#endif
#if defined(PNG_READ_tEXt_SUPPORTED)
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else if (!png_memcmp(png_ptr->chunk_name, png_tEXt, 4))
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{
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if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
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png_push_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length);
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}
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#endif
#if defined(PNG_READ_zTXt_SUPPORTED)
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else if (!png_memcmp(png_ptr->chunk_name, png_zTXt, 4))
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{
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if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
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png_push_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
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}
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#endif
#if defined(PNG_READ_iTXt_SUPPORTED)
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else if (!png_memcmp(png_ptr->chunk_name, png_iTXt, 4))
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{
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if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
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png_push_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
}
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#endif
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else
{
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if (png_ptr->push_length + 4 > png_ptr->buffer_size)
{
png_push_save_buffer(png_ptr);
return;
}
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png_push_handle_unknown(png_ptr, info_ptr, png_ptr->push_length);
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}
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png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
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}
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void /* PRIVATE */
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png_push_crc_skip(png_structp png_ptr, png_uint_32 skip)
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{
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png_ptr->process_mode = PNG_SKIP_MODE;
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png_ptr->skip_length = skip;
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}
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void /* PRIVATE */
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png_push_crc_finish(png_structp png_ptr)
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{
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if (png_ptr->skip_length && png_ptr->save_buffer_size)
{
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png_size_t save_size;
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if (png_ptr->skip_length < (png_uint_32)png_ptr->save_buffer_size)
save_size = (png_size_t)png_ptr->skip_length;
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else
save_size = png_ptr->save_buffer_size;
png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
png_ptr->skip_length -= save_size;
png_ptr->buffer_size -= save_size;
png_ptr->save_buffer_size -= save_size;
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png_ptr->save_buffer_ptr += save_size;
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}
if (png_ptr->skip_length && png_ptr->current_buffer_size)
{
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png_size_t save_size;
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if (png_ptr->skip_length < (png_uint_32)png_ptr->current_buffer_size)
save_size = (png_size_t)png_ptr->skip_length;
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else
save_size = png_ptr->current_buffer_size;
png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
png_ptr->skip_length -= save_size;
png_ptr->buffer_size -= save_size;
png_ptr->current_buffer_size -= save_size;
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png_ptr->current_buffer_ptr += save_size;
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}
if (!png_ptr->skip_length)
{
if (png_ptr->buffer_size < 4)
{
png_push_save_buffer(png_ptr);
return;
}
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png_crc_finish(png_ptr, 0);
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png_ptr->process_mode = PNG_READ_CHUNK_MODE;
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}
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}
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void PNGAPI
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png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
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{
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png_bytep ptr;
ptr = buffer;
if (png_ptr->save_buffer_size)
{
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png_size_t save_size;
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if (length < png_ptr->save_buffer_size)
save_size = length;
else
save_size = png_ptr->save_buffer_size;
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png_memcpy(ptr, png_ptr->save_buffer_ptr, save_size);
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length -= save_size;
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ptr += save_size;
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png_ptr->buffer_size -= save_size;
png_ptr->save_buffer_size -= save_size;
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png_ptr->save_buffer_ptr += save_size;
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}
if (length && png_ptr->current_buffer_size)
{
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png_size_t save_size;
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if (length < png_ptr->current_buffer_size)
save_size = length;
else
save_size = png_ptr->current_buffer_size;
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png_memcpy(ptr, png_ptr->current_buffer_ptr, save_size);
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png_ptr->buffer_size -= save_size;
png_ptr->current_buffer_size -= save_size;
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png_ptr->current_buffer_ptr += save_size;
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}
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}
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void /* PRIVATE */
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png_push_save_buffer(png_structp png_ptr)
{
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if (png_ptr->save_buffer_size)
{
if (png_ptr->save_buffer_ptr != png_ptr->save_buffer)
{
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png_size_t i,istop;
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png_bytep sp;
png_bytep dp;
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istop = png_ptr->save_buffer_size;
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for (i = 0, sp = png_ptr->save_buffer_ptr, dp = png_ptr->save_buffer;
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i < istop; i++, sp++, dp++)
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{
*dp = *sp;
}
}
}
if (png_ptr->save_buffer_size + png_ptr->current_buffer_size >
png_ptr->save_buffer_max)
{
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png_size_t new_max;
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png_bytep old_buffer;
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if (png_ptr->save_buffer_size > PNG_SIZE_MAX -
(png_ptr->current_buffer_size + 256))
{
png_error(png_ptr, "Potential overflow of save_buffer");
}
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new_max = png_ptr->save_buffer_size + png_ptr->current_buffer_size + 256;
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old_buffer = png_ptr->save_buffer;
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png_ptr->save_buffer = (png_bytep)png_malloc(png_ptr,
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(png_uint_32)new_max);
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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;
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}
if (png_ptr->current_buffer_size)
{
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png_memcpy(png_ptr->save_buffer + png_ptr->save_buffer_size,
png_ptr->current_buffer_ptr, png_ptr->current_buffer_size);
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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;
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}
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void /* PRIVATE */
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png_push_restore_buffer(png_structp png_ptr, png_bytep buffer,
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png_size_t buffer_length)
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{
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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;
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}
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void /* PRIVATE */
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png_push_read_IDAT(png_structp png_ptr)
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{
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#ifdef PNG_USE_LOCAL_ARRAYS
PNG_IDAT;
#endif
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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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if (png_ptr->buffer_size < 8)
{
png_push_save_buffer(png_ptr);
return;
}
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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, png_ptr->chunk_name, 4);
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png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
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if (png_memcmp(png_ptr->chunk_name, (png_bytep)png_IDAT, 4))
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{
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png_ptr->process_mode = PNG_READ_CHUNK_MODE;
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if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
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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)
{
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png_size_t save_size;
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if (png_ptr->idat_size < (png_uint_32)png_ptr->save_buffer_size)
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{
save_size = (png_size_t)png_ptr->idat_size;
/* check for overflow */
if((png_uint_32)save_size != png_ptr->idat_size)
png_error(png_ptr, "save_size overflowed in pngpread");
}
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else
save_size = png_ptr->save_buffer_size;
png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
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if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size);
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png_ptr->idat_size -= save_size;
png_ptr->buffer_size -= save_size;
png_ptr->save_buffer_size -= save_size;
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png_ptr->save_buffer_ptr += save_size;
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}
if (png_ptr->idat_size && png_ptr->current_buffer_size)
{
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png_size_t save_size;
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if (png_ptr->idat_size < (png_uint_32)png_ptr->current_buffer_size)
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{
save_size = (png_size_t)png_ptr->idat_size;
/* check for overflow */
if((png_uint_32)save_size != png_ptr->idat_size)
png_error(png_ptr, "save_size overflowed in pngpread");
}
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else
save_size = png_ptr->current_buffer_size;
png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
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if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
png_process_IDAT_data(png_ptr, png_ptr->current_buffer_ptr, save_size);
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png_ptr->idat_size -= save_size;
png_ptr->buffer_size -= save_size;
png_ptr->current_buffer_size -= save_size;
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png_ptr->current_buffer_ptr += save_size;
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}
if (!png_ptr->idat_size)
{
if (png_ptr->buffer_size <