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Change gzgetc() to a macro for speed (~40% speedup in testing).

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This commit is contained in:
Mark Adler
2011-09-26 22:50:28 -07:00
parent 8e0d212910
commit acfc85772a
5 changed files with 119 additions and 91 deletions
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25
zlib.h
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@@ -1186,7 +1186,7 @@ ZEXTERN int ZEXPORT uncompress OF((Bytef *dest, uLongf *destLen,
wrapper, documented in RFC 1952, wrapped around a deflate stream.
*/
typedef voidp gzFile; /* opaque gzip file descriptor */
typedef struct gzFile_s *gzFile; /* semi-opaque gzip file descriptor */
/*
ZEXTERN gzFile ZEXPORT gzopen OF((const char *path, const char *mode));
@@ -1322,10 +1322,13 @@ ZEXTERN int ZEXPORT gzputc OF((gzFile file, int c));
returns the value that was written, or -1 in case of error.
*/
ZEXTERN int ZEXPORT gzgetc OF((gzFile file));
/*
ZEXTERN int ZEXPORT gzgetc OF((gzFile file));
Reads one byte from the compressed file. gzgetc returns this byte or -1
in case of end of file or error.
in case of end of file or error. This is implemented as a macro for speed.
As such, it does not do all of the checking the other functions do. I.e.
it does not check to see if file is NULL, nor whether the structure file
points to has been clobbered or not.
*/
ZEXTERN int ZEXPORT gzungetc OF((int c, gzFile file));
@@ -1583,6 +1586,22 @@ ZEXTERN int ZEXPORT inflateBackInit_ OF((z_streamp strm, int windowBits,
inflateBackInit_((strm), (windowBits), (window), \
ZLIB_VERSION, (int)sizeof(z_stream))
/* gzgetc() macro and its supporting function and exposed data structure. Note
* that the real internal state is much larger than the exposed structure.
* This abbreviated structure exposes just enough for the gzgetc() macro. The
* user should not mess with these exposed elements, since their names or
* behavior could change in the future, perhaps even capriciously. They can
* only be used by the gzgetc() macro. You have been warned.
*/
struct gzFile_s {
unsigned have;
unsigned char *next;
z_off64_t pos;
};
ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file));
#define gzgetc(g) \
((g)->have ? ((g)->have--, (g)->pos++, *((g)->next)++) : gzgetc_(g))
/* provide 64-bit offset functions if _LARGEFILE64_SOURCE defined, and/or
* change the regular functions to 64 bits if _FILE_OFFSET_BITS is 64 (if
* both are true, the application gets the *64 functions, and the regular