mchapman/zlib
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Don't use library or built-in byte swaps.

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Using optimized byte swaps reduced portability for no real benefit,
since they are in parts of the code that represent a tiny fraction
of the execution time.  So a simple definition of a byte swap is
now used.
This commit is contained in:
Mark Adler
2012-03-03 00:03:30 -08:00
parent 513dfcc00e
commit 2547c6c81f
1 changed files with 2 additions and 13 deletions
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15
zutil.h
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@@ -246,18 +246,7 @@ extern const char * const z_errmsg[10]; /* indexed by 2-zlib_error */
#define TRY_FREE(s, p) {if (p) ZFREE(s, p);} #define TRY_FREE(s, p) {if (p) ZFREE(s, p);}
/* Reverse the bytes in a 32-bit value */ /* Reverse the bytes in a 32-bit value */
#ifndef Z_SOLO #define ZSWAP32(q) ((((q) >> 24) & 0xff) + (((q) >> 8) & 0xff00) + \
# if defined(_WIN32) && (_MSC_VER >= 1300) && (defined(_M_IX86) || defined(_M_X64)) (((q) & 0xff00) << 8) + (((q) & 0xff) << 24))
# include <stdlib.h>
# pragma intrinsic(_byteswap_ulong)
# define ZSWAP32(q) _byteswap_ulong(q)
# elif defined(__GNUC__) && ((__GNUC__ > 4) || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3))
# define ZSWAP32(q) __builtin_bswap32(q)
# endif
#endif
#ifndef ZSWAP32
# define ZSWAP32(q) ((((q) >> 24) & 0xff) + (((q) >> 8) & 0xff00) + \
(((q) & 0xff00) << 8) + (((q) & 0xff) << 24))
#endif
#endif /* ZUTIL_H */ #endif /* ZUTIL_H */