X-Git-Url: https://pd.if.org/git/?p=nbds;a=blobdiff_plain;f=include%2Fmurmur.h;h=cf54201281513d808bff662c6dbf576cfcd2ef7d;hp=fcb4cb642a9f08285d968135ca67f59712270e8e;hb=HEAD;hpb=4a7804bd08c790fc3c4233312e4b485c3302fe02 diff --git a/include/murmur.h b/include/murmur.h index fcb4cb6..cf54201 100644 --- a/include/murmur.h +++ b/include/murmur.h @@ -12,16 +12,16 @@ // 2. It will not produce the same results on little-endian and big-endian // machines. -static inline unsigned int murmur32 (const char *key, int len) +static inline uint32_t murmur32 (const char *key, int len) { // 'm' and 'r' are mixing constants generated offline. // They're not really 'magic', they just happen to work well. - const unsigned int m = 0x5bd1e995; + const uint32_t m = 0x5bd1e995; const int r = 24; // Initialize the hash to a 'random' value - unsigned int h = len; + uint32_t h = len; // Mix 4 bytes at a time into the hash @@ -61,3 +61,74 @@ static inline unsigned int murmur32 (const char *key, int len) return h; } + +static inline uint32_t murmur32_8b (uint64_t key) +{ + // 'm' and 'r' are mixing constants generated offline. + // They're not really 'magic', they just happen to work well. + + const uint32_t m = 0x5bd1e995; + const int r = 24; + + // Initialize the hash to a 'random' value + uint32_t h = 8; + + uint32_t k1 = (uint32_t)(key >> 32); + uint32_t k2 = (uint32_t)key; + + k1 *= m; + k1 ^= k1 >> r; + k1 *= m; + + k2 *= m; + k2 ^= k2 >> r; + k2 *= m; + + // Mix 4 bytes at a time into the hash + + h *= m; + h ^= k1; + h *= m; + h ^= k2; + + // Do a few final mixes of the hash to ensure the last few + // bytes are well-incorporated. + + h ^= h >> 13; + h *= m; + h ^= h >> 15; + + return h; +} + +static inline uint32_t murmur32_4b (uint32_t key) +{ + // 'm' and 'r' are mixing constants generated offline. + // They're not really 'magic', they just happen to work well. + + const uint32_t m = 0x5bd1e995; + const int r = 24; + + // Initialize the hash to a 'random' value + uint32_t h = 4; + + uint32_t k = *(uint32_t *)&key; + + k *= m; + k ^= k >> r; + k *= m; + + // Mix 4 bytes at a time into the hash + + h *= m; + h ^= k; + + // Do a few final mixes of the hash to ensure the last few + // bytes are well-incorporated. + + h ^= h >> 13; + h *= m; + h ^= h >> 15; + + return h; +}