58 lines
1.3 KiB
C++
58 lines
1.3 KiB
C++
/*
|
|
Copyright (c) 2013 Microsoft Corporation. All rights reserved.
|
|
Released under Apache 2.0 license as described in the file LICENSE.
|
|
|
|
Author: Leonardo de Moura
|
|
*/
|
|
#include "runtime/hash.h"
|
|
|
|
namespace lean {
|
|
|
|
//-----------------------------------------------------------------------------
|
|
// MurmurHash2, 64-bit versions, by Austin Appleby
|
|
// https://sites.google.com/site/murmurhash/
|
|
static uint64 MurmurHash64A(void const * key, size_t len, uint64 seed) {
|
|
const uint64 m = 0xc6a4a7935bd1e995;
|
|
const int r = 47;
|
|
|
|
uint64 h = seed ^ (len * m);
|
|
|
|
const uint64 * data = (const uint64 *)key;
|
|
const uint64 * end = data + (len/8);
|
|
|
|
while (data != end) {
|
|
uint64 k = *data++;
|
|
|
|
k *= m;
|
|
k ^= k >> r;
|
|
k *= m;
|
|
|
|
h ^= k;
|
|
h *= m;
|
|
}
|
|
|
|
const unsigned char * data2 = (const unsigned char *) data;
|
|
|
|
switch (len & 7) {
|
|
case 7: h ^= uint64(data2[6]) << 48;
|
|
case 6: h ^= uint64(data2[5]) << 40;
|
|
case 5: h ^= uint64(data2[4]) << 32;
|
|
case 4: h ^= uint64(data2[3]) << 24;
|
|
case 3: h ^= uint64(data2[2]) << 16;
|
|
case 2: h ^= uint64(data2[1]) << 8;
|
|
case 1: h ^= uint64(data2[0]);
|
|
h *= m;
|
|
};
|
|
|
|
h ^= h >> r;
|
|
h *= m;
|
|
h ^= h >> r;
|
|
|
|
return h;
|
|
}
|
|
|
|
uint64 hash_str(size_t len, unsigned char const * str, uint64 init_value) {
|
|
return MurmurHash64A(str, len, init_value);
|
|
}
|
|
|
|
}
|