com.orientechnologies.common.hash.OMurmurHash3 Maven / Gradle / Ivy
/*
*
* * Copyright 2014 Orient Technologies LTD (info(at)orientechnologies.com)
* *
* * Licensed under the Apache License, Version 2.0 (the "License");
* * you may not use this file except in compliance with the License.
* * You may obtain a copy of the License at
* *
* * http://www.apache.org/licenses/LICENSE-2.0
* *
* * Unless required by applicable law or agreed to in writing, software
* * distributed under the License is distributed on an "AS IS" BASIS,
* * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* * See the License for the specific language governing permissions and
* * limitations under the License.
* *
* * For more information: http://www.orientechnologies.com
*
*/
package com.orientechnologies.common.hash;
/**
* @since 13.08.12
*/
public class OMurmurHash3 {
static class State {
long h1;
long h2;
long k1;
long k2;
long c1;
long c2;
}
static long getblock(byte[] key, int i) {
return (((long) key[i + 0] & 0x00000000000000FFL)) | (((long) key[i + 1] & 0x00000000000000FFL) << 8)
| (((long) key[i + 2] & 0x00000000000000FFL) << 16) | (((long) key[i + 3] & 0x00000000000000FFL) << 24)
| (((long) key[i + 4] & 0x00000000000000FFL) << 32) | (((long) key[i + 5] & 0x00000000000000FFL) << 40)
| (((long) key[i + 6] & 0x00000000000000FFL) << 48) | (((long) key[i + 7] & 0x00000000000000FFL) << 56);
}
static void bmix(State state) {
state.k1 *= state.c1;
state.k1 = (state.k1 << 23) | (state.k1 >>> 64 - 23);
state.k1 *= state.c2;
state.h1 ^= state.k1;
state.h1 += state.h2;
state.h2 = (state.h2 << 41) | (state.h2 >>> 64 - 41);
state.k2 *= state.c2;
state.k2 = (state.k2 << 23) | (state.k2 >>> 64 - 23);
state.k2 *= state.c1;
state.h2 ^= state.k2;
state.h2 += state.h1;
state.h1 = state.h1 * 3 + 0x52dce729;
state.h2 = state.h2 * 3 + 0x38495ab5;
state.c1 = state.c1 * 5 + 0x7b7d159c;
state.c2 = state.c2 * 5 + 0x6bce6396;
}
static long fmix(long k) {
k ^= k >>> 33;
k *= 0xff51afd7ed558ccdL;
k ^= k >>> 33;
k *= 0xc4ceb9fe1a85ec53L;
k ^= k >>> 33;
return k;
}
public static long murmurHash3_x64_64(final byte[] key, final int seed) {
State state = new State();
state.h1 = 0x9368e53c2f6af274L ^ seed;
state.h2 = 0x586dcd208f7cd3fdL ^ seed;
state.c1 = 0x87c37b91114253d5L;
state.c2 = 0x4cf5ad432745937fL;
for (int i = 0; i < key.length / 16; i++) {
state.k1 = getblock(key, i * 2 * 8);
state.k2 = getblock(key, (i * 2 + 1) * 8);
bmix(state);
}
state.k1 = 0;
state.k2 = 0;
int tail = (key.length >>> 4) << 4;
switch (key.length & 15) {
case 15:
state.k2 ^= (long) key[tail + 14] << 48;
case 14:
state.k2 ^= (long) key[tail + 13] << 40;
case 13:
state.k2 ^= (long) key[tail + 12] << 32;
case 12:
state.k2 ^= (long) key[tail + 11] << 24;
case 11:
state.k2 ^= (long) key[tail + 10] << 16;
case 10:
state.k2 ^= (long) key[tail + 9] << 8;
case 9:
state.k2 ^= (long) key[tail + 8];
case 8:
state.k1 ^= (long) key[tail + 7] << 56;
case 7:
state.k1 ^= (long) key[tail + 6] << 48;
case 6:
state.k1 ^= (long) key[tail + 5] << 40;
case 5:
state.k1 ^= (long) key[tail + 4] << 32;
case 4:
state.k1 ^= (long) key[tail + 3] << 24;
case 3:
state.k1 ^= (long) key[tail + 2] << 16;
case 2:
state.k1 ^= (long) key[tail + 1] << 8;
case 1:
state.k1 ^= (long) key[tail + 0];
bmix(state);
}
state.h2 ^= key.length;
state.h1 += state.h2;
state.h2 += state.h1;
state.h1 = fmix(state.h1);
state.h2 = fmix(state.h2);
state.h1 += state.h2;
state.h2 += state.h1;
return state.h1;
}
}