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xs/murmur3.h  view on Meta::CPAN

#ifndef MURMUR3_H
#define MURMUR3_H

//-----------------------------------------------------------------------------
// MurmurHash3 was written by Austin Appleby, and is placed in the public
// domain. The author hereby disclaims copyright to this source code.

// Note - The x86 and x64 versions do _not_ produce the same results, as the
// algorithms are optimized for their respective platforms. You can still
// compile and run any of them on any platform, but your performance with the
// non-native version will be less than optimal.

//-----------------------------------------------------------------------------
// Platform-specific functions and macros

// Microsoft Visual Studio

#if defined(_MSC_VER)

#define FORCE_INLINE    __forceinline
typedef unsigned char uint8_t;
typedef unsigned long uint32_t;
typedef unsigned __int64 uint64_t;

// Other compilers

#else   // defined(_MSC_VER)
#include <stdint.h>

#endif // !defined(_MSC_VER)
#define FORCE_INLINE inline __attribute__((always_inline))

inline uint32_t rotl32(uint32_t x, int8_t r) {
    return (x << r) | (x >> (32 - r));
}

#define BIG_CONSTANT(x) (x##LLU)

/* NO-OP for little-endian platforms */
#if defined(__BYTE_ORDER__) && defined(__ORDER_LITTLE_ENDIAN__)
# if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
#   define BYTESWAP(x) (x)
# endif
/* if __BYTE_ORDER__ is not predefined (like FreeBSD), use arch */
#elif defined(__i386)  || defined(__x86_64) \
  ||  defined(__alpha) || defined(__vax)

# define BYTESWAP(x) (x)
/* use __builtin_bswap32 if available */
#elif defined(__GNUC__) || defined(__clang__)
#ifdef __has_builtin
#if __has_builtin(__builtin_bswap32)
#define BYTESWAP(x) __builtin_bswap32(x)
#endif // __has_builtin(__builtin_bswap32)
#endif // __has_builtin
#endif // defined(__GNUC__) || defined(__clang__)
/* last resort (big-endian w/o __builtin_bswap) */
#ifndef BYTESWAP
# define BYTESWAP(x)   ((((x)&0xFF)<<24) \
         |(((x)>>24)&0xFF) \
         |(((x)&0x0000FF00)<<8)    \
         |(((x)&0x00FF0000)>>8)    )
#endif

//-----------------------------------------------------------------------------
// Block read - if your platform needs to do endian-swapping or can only
// handle aligned reads, do the conversion here
#define getblock(p, i) BYTESWAP(p[i])