/*
* JBoss, Home of Professional Open Source
* Copyright 2011 Red Hat Inc. and/or its affiliates and other
* contributors as indicated by the @author tags. All rights reserved.
* See the copyright.txt in the distribution for a full listing of
* individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.streaminer.util.hash;
import java.nio.charset.Charset;
import java.util.Arrays;
/**
* MurmurHash3 implementation in Java, based on Austin Appleby's <a href=
* "https://code.google.com/p/smhasher/source/browse/trunk/MurmurHash3.cpp"
* >original in C</a>
*
* Only implementing x64 version, because this should always be faster on 64 bit
* native processors, even 64 bit being ran with a 32 bit OS; this should also
* be as fast or faster than the x86 version on some modern 32 bit processors.
*
* @author Patrick McFarland
* @see <a href="http://sites.google.com/site/murmurhash/">MurmurHash website</a>
* @see <a href="http://en.wikipedia.org/wiki/MurmurHash">MurmurHash entry on Wikipedia</a>
* @since 5.0
*/
public class MurmurHash3 extends Hash {
private static final Charset UTF8 = Charset.forName("UTF-8");
private static MurmurHash3 _instance = new MurmurHash3();
public static Hash getInstance() {
return _instance;
}
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) << 0)
| (((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;
}
/**
* Hash a value using the x64 128 bit variant of MurmurHash3
*
* @param key value to hash
* @param seed random value
* @return 128 bit hashed key, in an array containing two longs
*/
public static long[] MurmurHash3_x64_128(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] << 0;
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] << 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 new long[] { state.h1, state.h2 };
}
/**
* Hash a value using the x64 64 bit variant of MurmurHash3
*
* @param key value to hash
* @param seed random value
* @return 64 bit hashed key
*/
public static long MurmurHash3_x64_64(final byte[] key, final int seed) {
return MurmurHash3_x64_128(key, seed)[0];
}
/**
* Hash a value using the x64 32 bit variant of MurmurHash3
*
* @param key value to hash
* @param seed random value
* @return 32 bit hashed key
*/
public static int MurmurHash3_x64_32(final byte[] key, final int seed) {
return (int) (MurmurHash3_x64_128(key, seed)[0] >>> 32);
}
public long[] hash64(Object o, int seed) {
long[] result;
if (o instanceof byte[]) {
result = MurmurHash3_x64_128((byte[]) o, seed);
} else if (o instanceof long[]) {
result = MurmurHash3_x64_128((long[]) o, seed);
} else if (o instanceof String) {
result = MurmurHash3_x64_128(((String) o).getBytes(UTF8), seed);
} else {
result = MurmurHash3_x64_128(((Integer)o.hashCode()).toString().getBytes(UTF8), seed);
}
return Arrays.copyOfRange(result, 0, 2);
}
/**
* Hash a value using the x64 128 bit variant of MurmurHash3
*
* @param key value to hash
* @param seed random value
* @return 128 bit hashed key, in an array containing two longs
*/
public static long[] MurmurHash3_x64_128(final long[] 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 / 2; i++) {
state.k1 = key[i * 2];
state.k2 = key[i * 2 + 1];
bmix(state);
}
long tail = key[key.length - 1];
if (key.length % 2 != 0) {
state.k1 ^= tail;
bmix(state);
}
state.h2 ^= key.length * 8;
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 new long[] { state.h1, state.h2 };
}
/**
* Hash a value using the x64 64 bit variant of MurmurHash3
*
* @param key value to hash
* @param seed random value
* @return 64 bit hashed key
*/
public static long MurmurHash3_x64_64(final long[] key, final int seed) {
return MurmurHash3_x64_128(key, seed)[0];
}
/**
* Hash a value using the x64 32 bit variant of MurmurHash3
*
* @param key value to hash
* @param seed random value
* @return 32 bit hashed key
*/
public static int MurmurHash3_x64_32(final long[] key, final int seed) {
return (int) (MurmurHash3_x64_128(key, seed)[0] >>> 32);
}
@Override
public int hash(byte[] payload) {
return MurmurHash3_x64_32(payload, 9001);
}
/**
* Hashes a byte array efficiently.
*
* @param payload a byte array to hash
* @return a hash code for the byte array
*/
public int hash(long[] payload) {
return MurmurHash3_x64_32(payload, 9001);
}
public int hash(int hashcode) {
byte[] b = new byte[4];
b[0] = (byte) hashcode;
b[1] = (byte) (hashcode >>> 8);
b[2] = (byte) (hashcode >>> 16);
b[3] = (byte) (hashcode >>> 24);
return hash(b);
}
public int hash(Object o) {
if (o instanceof byte[])
return hash((byte[]) o);
else if (o instanceof long[])
return hash((long[]) o);
else if (o instanceof String)
return hash(((String) o).getBytes(UTF8));
else
return hash(o.hashCode());
}
@Override
public int hash(byte[] bytes, int length, int initval) {
return MurmurHash3_x64_32(bytes, initval);
}
@Override
public long hash64(Object o) {
return hash64(o, 9001)[0];
}
@Override
public long hash64(byte[] bytes, int length, int seed) {
return hash64(bytes, seed);
}
}