Java Hash Calculate hashInt(final int v)

Description

Quickly mixes the bits of an integer.

License

Open Source License

Declaration

public static int hashInt(final int v) 

Method Source Code

//package com.java2s;
/*/*w  ww  .  j a  va  2 s  . c o  m*/
 * Copyright (c) 2016 SnappyData, Inc. All rights reserved.
 *
 * 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. See accompanying
 * LICENSE file.
 */

public class Main {
    /** 2<sup>32</sup> &middot; &phi;, &phi; = (&#x221A;5 &minus; 1)/2. */
    private static final int INT_PHI = 0x9E3779B9;

    /** Quickly mixes the bits of an integer.
     *
     * <p>This method mixes the bits of the argument by multiplying by the
     * golden ratio and XORshifting the result. It is borrowed from
     * <a href="https://github.com/OpenHFT/Koloboke">Koloboke</a>, and
     * it has slightly worse behaviour than MurmurHash3 (in open-addressed
     * hash tables the average number of probes is slightly larger),
     * but it's much faster.
     */
    public static int hashInt(final int v) {
        final int h = v * INT_PHI;
        return h ^ (h >>> 16);
    }
}

Related

1. hashFNV32(int val)
2. hashFNV64(byte[] bytes)
3. hashForEqual(Class clazz)
4. hashHC(int i)
5. hashHsieh(int init, Object... vals)
6. hashIntArray(int seed, int[] data, int offset, int len)
7. hashIt(Object o)
8. hashJava32(byte[] byteList)
9. hashJava64(byte[] byteList)