cheng/libpng
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

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

Browse Source
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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
pngpriv.h
View File

@ -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

15
pngwutil.c
View File

@ -256,7 +256,12 @@ 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? */
if (!(png_ptr->mode & PNG_ZLIB_READY_FOR_ZTXT))
{
/* Free memory from previously opened zstream */
deflateEnd(&png_ptr->zstream);
/* 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);
@ -277,6 +282,8 @@ png_text_compress(png_structp png_ptr,
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
@ -778,6 +785,8 @@ 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 */
if (png_ptr->mode & PNG_ZLIB_READY_FOR_ZTXT)
{
/* Free memory from previously opened zstream */
deflateEnd(&png_ptr->zstream);
@ -801,6 +810,8 @@ png_write_IDAT(png_structp png_ptr, png_bytep data, png_size_t length)
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;
png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;