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[devel] Re-initialize the zlib compressor before compressing non-IDAT chunks.

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This commit is contained in:
Glenn Randers-Pehrson
2011-03-31 20:14:29 -05:00
parent dcc3505c7b
commit 6b3d50b2cd
9 changed files with 239 additions and 91 deletions
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109
pngwutil.c
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@@ -1,7 +1,7 @@
/* pngwutil.c - utilities to write a PNG file
*
* Last changed in libpng 1.5.0 [January 6, 2011]
* Last changed in libpng 1.5.3 [(PENDING RELEASE)]
* Copyright (c) 1998-2011 Glenn Randers-Pehrson
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
@@ -256,9 +256,33 @@ png_text_compress(png_structp png_ptr,
* wouldn't cause a failure, just a slowdown due to swapping).
*/
/* Initialize the compressor. To do: Why do we need this? */
ret = deflateInit2(&png_ptr->zstream, png_ptr->zlib_text_level,
png_ptr->zlib_text_method, png_ptr->zlib_text_window_bits,
png_ptr->zlib_text_mem_level, png_ptr->zlib_text_strategy);
if (ret != Z_OK)
{
if (ret == Z_VERSION_ERROR)
png_error(png_ptr,
"zlib failed to initialize compressor for text-- version error");
if (ret == Z_STREAM_ERROR)
png_error(png_ptr,
"zlib failed to initialize compressor for text-- stream error");
if (ret == Z_MEM_ERROR)
png_error(png_ptr,
"zlib failed to initialize compressor for text-- mem error");
png_error(png_ptr, "zlib failed to initialize compressor for text");
}
/* Set up the compression buffers */
/* TODO: the following cast hides a potential overflow problem. */
png_ptr->zstream.avail_in = (uInt)text_len;
/* NOTE: assume zlib doesn't overwrite the input */
png_ptr->zstream.next_in = (Bytef *)text;
png_ptr->zstream.avail_out = png_ptr->zbuf_size;
@@ -437,7 +461,6 @@ png_write_compressed_data_out(png_structp png_ptr, compression_state *comp)
/* Reset zlib for another zTXt/iTXt or image data */
deflateReset(&png_ptr->zstream);
png_ptr->zstream.data_type = Z_BINARY;
}
#endif
@@ -632,34 +655,34 @@ png_write_IHDR(png_structp png_ptr, png_uint_32 width, png_uint_32 height,
if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_METHOD))
png_ptr->zlib_method = 8;
#ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION
if (!(png_ptr->flags & PNG_FLAG_ZTXT_CUSTOM_STRATEGY))
png_ptr->zlib_text_strategy = Z_DEFAULT_STRATEGY;
if (!(png_ptr->flags & PNG_FLAG_ZTXT_CUSTOM_LEVEL))
png_ptr->zlib_text_level = Z_DEFAULT_COMPRESSION;
if (!(png_ptr->flags & PNG_FLAG_ZTXT_CUSTOM_MEM_LEVEL))
png_ptr->zlib_text_mem_level = 8;
if (!(png_ptr->flags & PNG_FLAG_ZTXT_CUSTOM_WINDOW_BITS))
png_ptr->zlib_text_window_bits = 15;
if (!(png_ptr->flags & PNG_FLAG_ZTXT_CUSTOM_METHOD))
png_ptr->zlib_text_method = 8;
#else
png_ptr->zlib_text_strategy = Z_DEFAULT_STRATEGY;
png_ptr->zlib_text_level = Z_DEFAULT_COMPRESSION;
png_ptr->zlib_text_mem_level = 8;
png_ptr->zlib_text_window_bits = 15;
png_ptr->zlib_text_method = 8;
#endif /* PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION */
/* Initialize the zlib compressor */
ret = deflateInit2(&png_ptr->zstream, png_ptr->zlib_level,
png_ptr->zlib_method, png_ptr->zlib_window_bits,
png_ptr->zlib_mem_level, png_ptr->zlib_strategy);
if (ret != Z_OK)
{
if (ret == Z_VERSION_ERROR)
png_error(png_ptr,
"zlib failed to initialize compressor -- version error");
if (ret == Z_STREAM_ERROR)
png_error(png_ptr,
"zlib failed to initialize compressor -- stream error");
if (ret == Z_MEM_ERROR)
png_error(png_ptr,
"zlib failed to initialize compressor -- mem error");
png_error(png_ptr, "zlib failed to initialize compressor");
}
png_ptr->zstream.next_out = png_ptr->zbuf;
png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
/* libpng is not interested in zstream.data_type, so set it
* to a predefined value, to avoid its evaluation inside zlib
*/
png_ptr->zstream.data_type = Z_BINARY;
png_ptr->mode = PNG_HAVE_IHDR;
}
@@ -750,7 +773,39 @@ png_write_IDAT(png_structp png_ptr, png_bytep data, png_size_t length)
if (!(png_ptr->mode & PNG_HAVE_IDAT) &&
png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
{
unsigned int z_cmf = data[0]; /* zlib compression method and flags */
int ret;
unsigned int z_cmf; /* zlib compression method and flags */
ret = deflateInit2(&png_ptr->zstream, png_ptr->zlib_level,
png_ptr->zlib_method, png_ptr->zlib_window_bits,
png_ptr->zlib_mem_level, png_ptr->zlib_strategy);
if (ret != Z_OK)
{
if (ret == Z_VERSION_ERROR)
png_error(png_ptr,
"zlib failed to initialize compressor -- version error");
if (ret == Z_STREAM_ERROR)
png_error(png_ptr,
"zlib failed to initialize compressor -- stream error");
if (ret == Z_MEM_ERROR)
png_error(png_ptr,
"zlib failed to initialize compressor -- mem error");
png_error(png_ptr, "zlib failed to initialize compressor");
}
png_ptr->zstream.next_out = png_ptr->zbuf;
png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
/* libpng is not interested in zstream.data_type, so set it
* to a predefined value, to avoid its evaluation inside zlib
*/
png_ptr->zstream.data_type = Z_BINARY;
z_cmf = data[0];
if ((z_cmf & 0x0f) == 8 && (z_cmf & 0xf0) <= 0x70)
{
/* Avoid memory underflows and multiplication overflows.