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org.apache.orc.util.Murmur3 Maven / Gradle / Ivy
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.
*/
package org.apache.orc.util;
/**
* Murmur3 is successor to Murmur2 fast non-crytographic hash algorithms.
*
* Murmur3 32 and 128 bit variants.
* 32-bit Java port of https://code.google.com/p/smhasher/source/browse/trunk/MurmurHash3.cpp#94
* 128-bit Java port of https://code.google.com/p/smhasher/source/browse/trunk/MurmurHash3.cpp#255
*
* This is a public domain code with no copyrights.
* From homepage of MurmurHash (https://code.google.com/p/smhasher/),
* "All MurmurHash versions are public domain software, and the author disclaims all copyright
* to their code."
*/
public class Murmur3 {
// from 64-bit linear congruential generator
public static final long NULL_HASHCODE = 2862933555777941757L;
// Constants for 32 bit variant
private static final int C1_32 = 0xcc9e2d51;
private static final int C2_32 = 0x1b873593;
private static final int R1_32 = 15;
private static final int R2_32 = 13;
private static final int M_32 = 5;
private static final int N_32 = 0xe6546b64;
// Constants for 128 bit variant
private static final long C1 = 0x87c37b91114253d5L;
private static final long C2 = 0x4cf5ad432745937fL;
private static final int R1 = 31;
private static final int R2 = 27;
private static final int R3 = 33;
private static final int M = 5;
private static final int N1 = 0x52dce729;
private static final int N2 = 0x38495ab5;
private static final int DEFAULT_SEED = 104729;
/**
* Murmur3 32-bit variant.
*
* @param data - input byte array
* @return - hashcode
*/
public static int hash32(byte[] data) {
return hash32(data, data.length, DEFAULT_SEED);
}
/**
* Murmur3 32-bit variant.
*
* @param data - input byte array
* @param length - length of array
* @param seed - seed. (default 0)
* @return - hashcode
*/
public static int hash32(byte[] data, int length, int seed) {
int hash = seed;
final int nblocks = length >> 2;
// body
for (int i = 0; i < nblocks; i++) {
int i_4 = i << 2;
int k = (data[i_4] & 0xff)
| ((data[i_4 + 1] & 0xff) << 8)
| ((data[i_4 + 2] & 0xff) << 16)
| ((data[i_4 + 3] & 0xff) << 24);
// mix functions
k *= C1_32;
k = Integer.rotateLeft(k, R1_32);
k *= C2_32;
hash ^= k;
hash = Integer.rotateLeft(hash, R2_32) * M_32 + N_32;
}
// tail
int idx = nblocks << 2;
int k1 = 0;
switch (length - idx) {
case 3:
k1 ^= data[idx + 2] << 16;
case 2:
k1 ^= data[idx + 1] << 8;
case 1:
k1 ^= data[idx];
// mix functions
k1 *= C1_32;
k1 = Integer.rotateLeft(k1, R1_32);
k1 *= C2_32;
hash ^= k1;
}
// finalization
hash ^= length;
hash ^= (hash >>> 16);
hash *= 0x85ebca6b;
hash ^= (hash >>> 13);
hash *= 0xc2b2ae35;
hash ^= (hash >>> 16);
return hash;
}
/**
* Murmur3 64-bit variant. This is essentially MSB 8 bytes of Murmur3 128-bit variant.
*
* @param data - input byte array
* @return - hashcode
*/
public static long hash64(byte[] data) {
return hash64(data, 0, data.length, DEFAULT_SEED);
}
public static long hash64(byte[] data, int offset, int length) {
return hash64(data, offset, length, DEFAULT_SEED);
}
/**
* Murmur3 64-bit variant. This is essentially MSB 8 bytes of Murmur3 128-bit variant.
*
* @param data - input byte array
* @param length - length of array
* @param seed - seed. (default is 0)
* @return - hashcode
*/
public static long hash64(byte[] data, int offset, int length, int seed) {
long hash = seed;
final int nblocks = length >> 3;
// body
for (int i = 0; i < nblocks; i++) {
final int i8 = i << 3;
long k = ((long) data[offset + i8] & 0xff)
| (((long) data[offset + i8 + 1] & 0xff) << 8)
| (((long) data[offset + i8 + 2] & 0xff) << 16)
| (((long) data[offset + i8 + 3] & 0xff) << 24)
| (((long) data[offset + i8 + 4] & 0xff) << 32)
| (((long) data[offset + i8 + 5] & 0xff) << 40)
| (((long) data[offset + i8 + 6] & 0xff) << 48)
| (((long) data[offset + i8 + 7] & 0xff) << 56);
// mix functions
k *= C1;
k = Long.rotateLeft(k, R1);
k *= C2;
hash ^= k;
hash = Long.rotateLeft(hash, R2) * M + N1;
}
// tail
long k1 = 0;
int tailStart = nblocks << 3;
switch (length - tailStart) {
case 7:
k1 ^= ((long) data[offset + tailStart + 6] & 0xff) << 48;
case 6:
k1 ^= ((long) data[offset + tailStart + 5] & 0xff) << 40;
case 5:
k1 ^= ((long) data[offset + tailStart + 4] & 0xff) << 32;
case 4:
k1 ^= ((long) data[offset + tailStart + 3] & 0xff) << 24;
case 3:
k1 ^= ((long) data[offset + tailStart + 2] & 0xff) << 16;
case 2:
k1 ^= ((long) data[offset + tailStart + 1] & 0xff) << 8;
case 1:
k1 ^= ((long) data[offset + tailStart] & 0xff);
k1 *= C1;
k1 = Long.rotateLeft(k1, R1);
k1 *= C2;
hash ^= k1;
}
// finalization
hash ^= length;
hash = fmix64(hash);
return hash;
}
/**
* Murmur3 128-bit variant.
*
* @param data - input byte array
* @return - hashcode (2 longs)
*/
public static long[] hash128(byte[] data) {
return hash128(data, 0, data.length, DEFAULT_SEED);
}
/**
* Murmur3 128-bit variant.
*
* @param data - input byte array
* @param offset - the first element of array
* @param length - length of array
* @param seed - seed. (default is 0)
* @return - hashcode (2 longs)
*/
public static long[] hash128(byte[] data, int offset, int length, int seed) {
long h1 = seed;
long h2 = seed;
final int nblocks = length >> 4;
// body
for (int i = 0; i < nblocks; i++) {
final int i16 = i << 4;
long k1 = ((long) data[offset + i16] & 0xff)
| (((long) data[offset + i16 + 1] & 0xff) << 8)
| (((long) data[offset + i16 + 2] & 0xff) << 16)
| (((long) data[offset + i16 + 3] & 0xff) << 24)
| (((long) data[offset + i16 + 4] & 0xff) << 32)
| (((long) data[offset + i16 + 5] & 0xff) << 40)
| (((long) data[offset + i16 + 6] & 0xff) << 48)
| (((long) data[offset + i16 + 7] & 0xff) << 56);
long k2 = ((long) data[offset + i16 + 8] & 0xff)
| (((long) data[offset + i16 + 9] & 0xff) << 8)
| (((long) data[offset + i16 + 10] & 0xff) << 16)
| (((long) data[offset + i16 + 11] & 0xff) << 24)
| (((long) data[offset + i16 + 12] & 0xff) << 32)
| (((long) data[offset + i16 + 13] & 0xff) << 40)
| (((long) data[offset + i16 + 14] & 0xff) << 48)
| (((long) data[offset + i16 + 15] & 0xff) << 56);
// mix functions for k1
k1 *= C1;
k1 = Long.rotateLeft(k1, R1);
k1 *= C2;
h1 ^= k1;
h1 = Long.rotateLeft(h1, R2);
h1 += h2;
h1 = h1 * M + N1;
// mix functions for k2
k2 *= C2;
k2 = Long.rotateLeft(k2, R3);
k2 *= C1;
h2 ^= k2;
h2 = Long.rotateLeft(h2, R1);
h2 += h1;
h2 = h2 * M + N2;
}
// tail
long k1 = 0;
long k2 = 0;
int tailStart = nblocks << 4;
switch (length - tailStart) {
case 15:
k2 ^= (long) (data[offset + tailStart + 14] & 0xff) << 48;
case 14:
k2 ^= (long) (data[offset + tailStart + 13] & 0xff) << 40;
case 13:
k2 ^= (long) (data[offset + tailStart + 12] & 0xff) << 32;
case 12:
k2 ^= (long) (data[offset + tailStart + 11] & 0xff) << 24;
case 11:
k2 ^= (long) (data[offset + tailStart + 10] & 0xff) << 16;
case 10:
k2 ^= (long) (data[offset + tailStart + 9] & 0xff) << 8;
case 9:
k2 ^= (long) (data[offset + tailStart + 8] & 0xff);
k2 *= C2;
k2 = Long.rotateLeft(k2, R3);
k2 *= C1;
h2 ^= k2;
case 8:
k1 ^= (long) (data[offset + tailStart + 7] & 0xff) << 56;
case 7:
k1 ^= (long) (data[offset + tailStart + 6] & 0xff) << 48;
case 6:
k1 ^= (long) (data[offset + tailStart + 5] & 0xff) << 40;
case 5:
k1 ^= (long) (data[offset + tailStart + 4] & 0xff) << 32;
case 4:
k1 ^= (long) (data[offset + tailStart + 3] & 0xff) << 24;
case 3:
k1 ^= (long) (data[offset + tailStart + 2] & 0xff) << 16;
case 2:
k1 ^= (long) (data[offset + tailStart + 1] & 0xff) << 8;
case 1:
k1 ^= (long) (data[offset + tailStart] & 0xff);
k1 *= C1;
k1 = Long.rotateLeft(k1, R1);
k1 *= C2;
h1 ^= k1;
}
// finalization
h1 ^= length;
h2 ^= length;
h1 += h2;
h2 += h1;
h1 = fmix64(h1);
h2 = fmix64(h2);
h1 += h2;
h2 += h1;
return new long[]{h1, h2};
}
private static long fmix64(long h) {
h ^= (h >>> 33);
h *= 0xff51afd7ed558ccdL;
h ^= (h >>> 33);
h *= 0xc4ceb9fe1a85ec53L;
h ^= (h >>> 33);
return h;
}
}
