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/*
* 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.commons.codec.digest;
/**
* MurmurHash3 yields a 32-bit or 128-bit value.
*
* MurmurHash is a non-cryptographic hash function suitable for general
* hash-based lookup. The name comes from two basic operations, multiply (MU)
* and rotate (R), used in its inner loop. Unlike cryptographic hash functions,
* it is not specifically designed to be difficult to reverse by an adversary,
* making it unsuitable for cryptographic purposes.
*
* 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."
*
* Copied from Apache Hive:
* https://github.com/apache/hive/blob/master/storage-api/src/java/org/apache/hive/common/util/Murmur3.java
*
* @see MurmurHash
* @since 1.13
*/
public final class MurmurHash3 {
/** TODO Replace on Java 8 with Long.BYTES. */
static final int LONG_BYTES = Long.SIZE / Byte.SIZE;
/** TODO Replace on Java 8 with Integer.BYTES. */
static final int INTEGER_BYTES = Integer.SIZE / Byte.SIZE;
/** TODO Replace on Java 8 with Short.BYTES. */
static final int SHORT_BYTES = Short.SIZE / Byte.SIZE;
// 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;
public static final int DEFAULT_SEED = 104729;
// all methods static; private constructor.
private MurmurHash3() {
}
/**
* Generates 32 bit hash from two longs with default seed value.
*
* @param l0 long to hash
* @param l1 long to hash
* @return 32 bit hash
*/
public static int hash32(final long l0, final long l1) {
return hash32(l0, l1, DEFAULT_SEED);
}
/**
* Generates 32 bit hash from a long with default seed value.
*
* @param l0 long to hash
* @return 32 bit hash
*/
public static int hash32(final long l0) {
return hash32(l0, DEFAULT_SEED);
}
/**
* Generates 32 bit hash from a long with the given seed.
*
* @param l0 long to hash
* @param seed initial seed value
* @return 32 bit hash
*/
public static int hash32(final long l0, final int seed) {
int hash = seed;
final long r0 = Long.reverseBytes(l0);
hash = mix32((int) r0, hash);
hash = mix32((int) (r0 >>> 32), hash);
return fmix32(LONG_BYTES, hash);
}
/**
* Generates 32 bit hash from two longs with the given seed.
*
* @param l0 long to hash
* @param l1 long to hash
* @param seed initial seed value
* @return 32 bit hash
*/
public static int hash32(final long l0, final long l1, final int seed) {
int hash = seed;
final long r0 = Long.reverseBytes(l0);
final long r1 = Long.reverseBytes(l1);
hash = mix32((int) r0, hash);
hash = mix32((int) (r0 >>> 32), hash);
hash = mix32((int) (r1), hash);
hash = mix32((int) (r1 >>> 32), hash);
return fmix32(LONG_BYTES * 2, hash);
}
/**
* Generates 32 bit hash from byte array with the default seed.
*
* @param data - input byte array
* @return 32 bit hash
*/
public static int hash32(final byte[] data) {
return hash32(data, 0, data.length, DEFAULT_SEED);
}
/**
* Generates 32 bit hash from a string with the default seed.
*
* @param data - input string
* @return 32 bit hash
*/
public static int hash32(final String data) {
final byte[] origin = data.getBytes();
return hash32(origin, 0, origin.length, DEFAULT_SEED);
}
/**
* Generates 32 bit hash from byte array with the default seed.
*
* @param data - input byte array
* @param length - length of array
* @return 32 bit hash
*/
public static int hash32(final byte[] data, final int length) {
return hash32(data, length, DEFAULT_SEED);
}
/**
* Generates 32 bit hash from byte array with the given length and seed.
*
* @param data - input byte array
* @param length - length of array
* @param seed - seed. (default 0)
* @return 32 bit hash
*/
public static int hash32(final byte[] data, final int length, final int seed) {
return hash32(data, 0, length, seed);
}
/**
* Generates 32 bit hash from byte array with the given length, offset and seed.
*
* @param data - input byte array
* @param offset - offset of data
* @param length - length of array
* @param seed - seed. (default 0)
* @return 32 bit hash
*/
public static int hash32(final byte[] data, final int offset, final int length, final int seed) {
int hash = seed;
final int nblocks = length >> 2;
// body
for (int i = 0; i < nblocks; i++) {
final int i_4 = i << 2;
final int k = (data[offset + i_4] & 0xff) | ((data[offset + i_4 + 1] & 0xff) << 8)
| ((data[offset + i_4 + 2] & 0xff) << 16) | ((data[offset + i_4 + 3] & 0xff) << 24);
hash = mix32(k, hash);
}
// tail
final int idx = nblocks << 2;
int k1 = 0;
switch (length - idx) {
case 3:
k1 ^= data[offset + idx + 2] << 16;
case 2:
k1 ^= data[offset + idx + 1] << 8;
case 1:
k1 ^= data[offset + idx];
// mix functions
k1 *= C1_32;
k1 = Integer.rotateLeft(k1, R1_32);
k1 *= C2_32;
hash ^= k1;
}
return fmix32(length, hash);
}
/**
* Murmur3 64-bit variant. This is essentially MSB 8 bytes of Murmur3 128-bit
* variant.
*
* @param data - input byte array
* @return 64 bit hash
*/
public static long hash64(final byte[] data) {
return hash64(data, 0, data.length, DEFAULT_SEED);
}
/**
* Murmur3 64-bit variant. This is essentially MSB 8 bytes of Murmur3 128-bit
* variant.
*
* @param data - input long
* @return 64 bit hash
*/
public static long hash64(final long data) {
long hash = DEFAULT_SEED;
long k = Long.reverseBytes(data);
final int length = LONG_BYTES;
// mix functions
k *= C1;
k = Long.rotateLeft(k, R1);
k *= C2;
hash ^= k;
hash = Long.rotateLeft(hash, R2) * M + N1;
// finalization
hash ^= length;
hash = fmix64(hash);
return hash;
}
/**
* Murmur3 64-bit variant. This is essentially MSB 8 bytes of Murmur3 128-bit
* variant.
*
* @param data - input int
* @return 64 bit hash
*/
public static long hash64(final int data) {
long k1 = Integer.reverseBytes(data) & (-1L >>> 32);
final int length = INTEGER_BYTES;
long hash = DEFAULT_SEED;
k1 *= C1;
k1 = Long.rotateLeft(k1, R1);
k1 *= C2;
hash ^= k1;
// finalization
hash ^= length;
hash = fmix64(hash);
return hash;
}
/**
* Murmur3 64-bit variant. This is essentially MSB 8 bytes of Murmur3 128-bit
* variant.
*
* @param data - input short
* @return 64 bit hash
*/
public static long hash64(final short data) {
long hash = DEFAULT_SEED;
long k1 = 0;
k1 ^= ((long) data & 0xff) << 8;
k1 ^= ((long) ((data & 0xFF00) >> 8) & 0xff);
k1 *= C1;
k1 = Long.rotateLeft(k1, R1);
k1 *= C2;
hash ^= k1;
// finalization
hash ^= SHORT_BYTES;
hash = fmix64(hash);
return hash;
}
/**
* Generates 64 bit hash from byte array with the given length, offset and
* default seed.
*
* @param data - input byte array
* @param offset - offset of data
* @param length - length of array
* @return 64 bit hash
*/
public static long hash64(final byte[] data, final int offset, final int length) {
return hash64(data, offset, length, DEFAULT_SEED);
}
/**
* Generates 64 bit hash from byte array with the given length, offset and seed.
*
* @param data - input byte array
* @param offset - offset of data
* @param length - length of array
* @param seed - seed. (default 0)
* @return 64 bit hash
*/
public static long hash64(final byte[] data, final int offset, final int length, final 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;
final 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 - 128 bit hash (2 longs)
*/
public static long[] hash128(final byte[] data) {
return hash128(data, 0, data.length, DEFAULT_SEED);
}
/**
* Murmur3 128-bit variant.
*
* @param data - input String
* @return - 128 bit hash (2 longs)
*/
public static long[] hash128(final String data) {
final byte[] origin = data.getBytes();
return hash128(origin, 0, origin.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 - 128 bit hash (2 longs)
*/
public static long[] hash128(final byte[] data, final int offset, final int length, final 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;
final 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 ^= 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 ^= 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 int mix32(int k, int hash) {
k *= C1_32;
k = Integer.rotateLeft(k, R1_32);
k *= C2_32;
hash ^= k;
return Integer.rotateLeft(hash, R2_32) * M_32 + N_32;
}
private static int fmix32(final int length, int hash) {
hash ^= length;
hash ^= (hash >>> 16);
hash *= 0x85ebca6b;
hash ^= (hash >>> 13);
hash *= 0xc2b2ae35;
hash ^= (hash >>> 16);
return hash;
}
private static long fmix64(long h) {
h ^= (h >>> 33);
h *= 0xff51afd7ed558ccdL;
h ^= (h >>> 33);
h *= 0xc4ceb9fe1a85ec53L;
h ^= (h >>> 33);
return h;
}
public static class IncrementalHash32 {
byte[] tail = new byte[3];
int tailLen;
int totalLen;
int hash;
public final void start(final int hash) {
tailLen = totalLen = 0;
this.hash = hash;
}
public final void add(final byte[] data, int offset, final int length) {
if (length == 0) {
return;
}
totalLen += length;
if (tailLen + length < 4) {
System.arraycopy(data, offset, tail, tailLen, length);
tailLen += length;
return;
}
int offset2 = 0;
if (tailLen > 0) {
offset2 = (4 - tailLen);
int k = -1;
switch (tailLen) {
case 1:
k = orBytes(tail[0], data[offset], data[offset + 1], data[offset + 2]);
break;
case 2:
k = orBytes(tail[0], tail[1], data[offset], data[offset + 1]);
break;
case 3:
k = orBytes(tail[0], tail[1], tail[2], data[offset]);
break;
default:
throw new AssertionError(tailLen);
}
// 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;
}
final int length2 = length - offset2;
offset += offset2;
final int nblocks = length2 >> 2;
for (int i = 0; i < nblocks; i++) {
final int i_4 = (i << 2) + offset;
int k = orBytes(data[i_4], data[i_4 + 1], data[i_4 + 2], data[i_4 + 3]);
// 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;
}
final int consumed = (nblocks << 2);
tailLen = length2 - consumed;
if (consumed == length2) {
return;
}
System.arraycopy(data, offset + consumed, tail, 0, tailLen);
}
public final int end() {
int k1 = 0;
switch (tailLen) {
case 3:
k1 ^= tail[2] << 16;
case 2:
k1 ^= tail[1] << 8;
case 1:
k1 ^= tail[0];
// mix functions
k1 *= C1_32;
k1 = Integer.rotateLeft(k1, R1_32);
k1 *= C2_32;
hash ^= k1;
}
// finalization
hash ^= totalLen;
hash ^= (hash >>> 16);
hash *= 0x85ebca6b;
hash ^= (hash >>> 13);
hash *= 0xc2b2ae35;
hash ^= (hash >>> 16);
return hash;
}
}
private static int orBytes(final byte b1, final byte b2, final byte b3, final byte b4) {
return (b1 & 0xff) | ((b2 & 0xff) << 8) | ((b3 & 0xff) << 16) | ((b4 & 0xff) << 24);
}
}