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[devel] Use a mode bit to avoid reopening the zstream except when necessary.

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This commit is contained in:
Glenn Randers-Pehrson 2011-03-31 22:06:04 -05:00
parent ed8aab4d85
commit f83783115f
2 changed files with 45 additions and 33 deletions
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1
pngpriv.h
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@ -277,6 +277,7 @@ typedef PNG_CONST png_uint_16p FAR * png_const_uint_16pp;
#define PNG_BACKGROUND_IS_GRAY 0x800
#define PNG_HAVE_PNG_SIGNATURE 0x1000
#define PNG_HAVE_CHUNK_AFTER_IDAT 0x2000 /* Have another chunk after IDAT */
#define PNG_ZLIB_READY_FOR_ZTXT 0x4000 /* 1: ready for ZTXT; 0: for IDAT */
/* Flags for the transformations the PNG library does on the image data */
#define PNG_BGR 0x0001

77
pngwutil.c
View File

@ -256,26 +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 (!(png_ptr->mode & PNG_ZLIB_READY_FOR_ZTXT))
{
/* Free memory from previously opened zstream */
deflateEnd(&png_ptr->zstream);
if (ret != Z_OK)
{
if (ret == Z_VERSION_ERROR)
png_error(png_ptr,
"zlib failed to initialize compressor for text-- version error");
/* Initialize the compressor for zTXt compression. */
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_STREAM_ERROR)
png_error(png_ptr,
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,
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");
png_error(png_ptr, "zlib failed to initialize compressor for text");
}
png_ptr->mode |= PNG_ZLIB_READY_FOR_ZTXT;
}
/* Set up the compression buffers */
@ -685,7 +692,7 @@ png_write_IHDR(png_structp png_ptr, png_uint_32 width, png_uint_32 height,
png_ptr->zlib_method, png_ptr->zlib_window_bits,
png_ptr->zlib_mem_level, png_ptr->zlib_strategy);
png_ptr->mode = PNG_HAVE_IHDR;
png_ptr->mode = PNG_HAVE_IHDR; /* not READY_FOR_ZTXT */
}
/* Write the palette. We are careful not to trust png_color to be in the
@ -778,28 +785,32 @@ png_write_IDAT(png_structp png_ptr, png_bytep data, png_size_t length)
int ret;
unsigned int z_cmf; /* zlib compression method and flags */
/* Free memory from previously opened zstream */
deflateEnd(&png_ptr->zstream);
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 (png_ptr->mode & PNG_ZLIB_READY_FOR_ZTXT)
{
if (ret == Z_VERSION_ERROR)
png_error(png_ptr,
"zlib failed to initialize compressor -- version error");
/* Free memory from previously opened zstream */
deflateEnd(&png_ptr->zstream);
if (ret == Z_STREAM_ERROR)
png_error(png_ptr,
"zlib failed to initialize compressor -- stream error");
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_MEM_ERROR)
png_error(png_ptr,
"zlib failed to initialize compressor -- mem error");
if (ret != Z_OK)
{
if (ret == Z_VERSION_ERROR)
png_error(png_ptr,
"zlib failed to initialize compressor -- version error");
png_error(png_ptr, "zlib failed to initialize compressor");
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->mode &= ~PNG_ZLIB_READY_FOR_ZTXT; /* Ready for IDAT */
}
png_ptr->zstream.next_out = png_ptr->zbuf;