#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 ROTL32(x,y) rotl32(x,y)

#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])

//-----------------------------------------------------------------------------
// Finalization mix - force all bits of a hash block to avalanche

FORCE_INLINE uint32_t fmix32(uint32_t h) {
    h ^= h >> 16;
    h *= 0x85ebca6b;
    h ^= h >> 13;
    h *= 0xc2b2ae35;
    h ^= h >> 16;

    return h;
}

//-----------------------------------------------------------------------------

#ifdef __cplusplus
extern "C"
#else
extern
#endif
void MurmurHash3_32(const void * key, int len, uint32_t seed, void * out) {
    const uint8_t * data = (const uint8_t*) key;
    const int nblocks = len / 4;
    int i;

    uint32_t h1 = seed;

    uint32_t c1 = 0xcc9e2d51;
    uint32_t c2 = 0x1b873593;

    //----------
    // body

    const uint32_t * blocks = (const uint32_t *) (data + nblocks * 4);

    for (i = -nblocks; i; i++) {
        uint32_t k1 = getblock(blocks,i);

        k1 *= c1;
        k1 = ROTL32(k1,15);
        k1 *= c2;

        h1 ^= k1;
        h1 = ROTL32(h1,13);
        h1 = h1 * 5 + 0xe6546b64;
    }

    //----------
    // tail
    {
        const uint8_t * tail = (const uint8_t*) (data + nblocks * 4);

        uint32_t k1 = 0;

        switch (len & 3) {
        case 3:
            k1 ^= tail[2] << 16;
        case 2:
            k1 ^= tail[1] << 8;
        case 1:
            k1 ^= tail[0];
            k1 *= c1;
            k1 = ROTL32(k1,15);
            k1 *= c2;
            h1 ^= k1;
        };
    }

    //----------
    // finalization

    h1 ^= len;

    h1 = fmix32(h1);

    *(uint32_t*) out = h1;
}

#endif