Java Murmur Hash murmurHash(byte[] data, int offset, int length)

Here you can find the source of murmurHash(byte[] data, int offset, int length)

Description

murmur Hash

License

Apache License

Declaration

public static int murmurHash(byte[] data, int offset, int length) 

Method Source Code

//package com.java2s;
/**//from  ww w . j a  va  2  s.c o  m
 * 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.
 */

public class Main {
    public static int murmurHash(byte[] data, int offset, int length) {
        int m = 0x5bd1e995;
        int r = 24;

        int h = length;

        int len_4 = length >> 2;

        for (int i = 0; i < len_4; i++) {
            int i_4 = offset + (i << 2);
            int k = data[i_4 + 3];
            k = k << 8;
            k = k | (data[i_4 + 2] & 0xff);
            k = k << 8;
            k = k | (data[i_4 + 1] & 0xff);
            k = k << 8;
            k = k | (data[i_4 + 0] & 0xff);
            k *= m;
            k ^= k >>> r;
            k *= m;
            h *= m;
            h ^= k;
        }

        // avoid calculating modulo
        int len_m = len_4 << 2;
        int left = length - len_m;

        if (left != 0) {
            length += offset;
            if (left >= 3) {
                h ^= (int) data[length - 3] << 16;
            }
            if (left >= 2) {
                h ^= (int) data[length - 2] << 8;
            }
            if (left >= 1) {
                h ^= (int) data[length - 1];
            }

            h *= m;
        }

        h ^= h >>> 13;
        h *= m;
        h ^= h >>> 15;

        return h;
    }
}

Related

  1. murmur(String str, int seed)
  2. murmur2(final byte[] data)
  3. murmur2(int value, int salt)
  4. murmur3fmix(int value)
  5. murmurHash(int code)
  6. murmurhash2_64(final byte[] data, int length, int seed)
  7. murmurHash3(int k)
  8. murmurHash3(int x)