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Imported from libpng-1.0.5c.tar

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This commit is contained in:
Glenn Randers-Pehrson
1999-11-27 10:22:33 -06:00
parent 6d8f3b080a
commit 5379b24536
46 changed files with 720 additions and 178 deletions
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45
pngpread.c
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@@ -1,7 +1,7 @@
/* pngpread.c - read a png file in push mode
*
* libpng 1.0.5a - October 23, 1999
* libpng 1.0.5c - November 27, 1999
* For conditions of distribution and use, see copyright notice in png.h
* Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
* Copyright (c) 1996, 1997 Andreas Dilger
@@ -116,13 +116,14 @@ png_push_read_sig(png_structp png_ptr, png_infop info_ptr)
void
png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
{
#include "pngtypes.h"
/* First we make sure we have enough data for the 4 byte chunk name
* 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).
*/
if (!(png_ptr->flags & PNG_FLAG_HAVE_CHUNK_HEADER))
if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
{
png_byte chunk_length[4];
@@ -136,7 +137,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
png_ptr->push_length = png_get_uint_32(chunk_length);
png_reset_crc(png_ptr);
png_crc_read(png_ptr, png_ptr->chunk_name, 4);
png_ptr->flags |= PNG_FLAG_HAVE_CHUNK_HEADER;
png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
}
if (!png_memcmp(png_ptr->chunk_name, png_IHDR, 4))
@@ -159,7 +160,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
}
else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
else if (!png_memcmp(png_ptr->chunk_name, (png_bytep)png_IDAT, 4))
{
/* If we reach an IDAT chunk, this means we have read all of the
* header chunks, and we can start reading the image (or if this
@@ -343,7 +344,7 @@ png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
png_push_handle_unknown(png_ptr, info_ptr, png_ptr->push_length);
}
png_ptr->flags &= ~PNG_FLAG_HAVE_CHUNK_HEADER;
png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
}
void
@@ -496,7 +497,8 @@ png_push_restore_buffer(png_structp png_ptr, png_bytep buffer,
void
png_push_read_IDAT(png_structp png_ptr)
{
if (!(png_ptr->flags & PNG_FLAG_HAVE_CHUNK_HEADER))
const png_byte png_IDAT[5] = { 73, 68, 65, 84, '\0'};
if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
{
png_byte chunk_length[4];
@@ -511,9 +513,9 @@ png_push_read_IDAT(png_structp png_ptr)
png_reset_crc(png_ptr);
png_crc_read(png_ptr, png_ptr->chunk_name, 4);
png_ptr->flags |= PNG_FLAG_HAVE_CHUNK_HEADER;
png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
if (png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
if (png_memcmp(png_ptr->chunk_name, (png_bytep)png_IDAT, 4))
{
png_ptr->process_mode = PNG_READ_CHUNK_MODE;
if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
@@ -576,7 +578,7 @@ png_push_read_IDAT(png_structp png_ptr)
}
png_crc_finish(png_ptr, 0);
png_ptr->flags &= ~PNG_FLAG_HAVE_CHUNK_HEADER;
png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
}
}
@@ -767,6 +769,30 @@ png_push_process_row(png_structp png_ptr)
void
png_read_push_finish_row(png_structp png_ptr)
{
/* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
/* start of interlace block */
const int png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
/* offset to next interlace block */
const int png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
/* start of interlace block in the y direction */
const int png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
/* offset to next interlace block in the y direction */
const int png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
/* Width of interlace block. This is not currently used - if you need
* it, uncomment it here and in png.h
const int png_pass_width[] = {8, 4, 4, 2, 2, 1, 1};
*/
/* Height of interlace block. This is not currently used - if you need
* it, uncomment it here and in png.h
const int png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
*/
png_ptr->row_number++;
if (png_ptr->row_number < png_ptr->num_rows)
return;
@@ -1115,6 +1141,7 @@ void
png_progressive_combine_row (png_structp png_ptr,
png_bytep old_row, png_bytep new_row)
{
const int png_pass_dsp_mask[7] = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
if (new_row != NULL) /* new_row must == png_ptr->row_buf here. */
png_combine_row(png_ptr, old_row, png_pass_dsp_mask[png_ptr->pass]);
}