FNV Hash : Hash Code « Development Class « Java






FNV Hash

      
/*
 * @(#)$Id$
 *
 * Copyright 2006-2008 Makoto YUI
 *
 * 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.
 * 
 * Contributors:
 *     Makoto YUI - initial implementation
 */
//package xbird.util.hashes;


/**
 * 
 * <DIV lang="en"></DIV>
 * <DIV lang="ja"></DIV>
 * 
 * @author Makoto YUI (yuin405+xbird@gmail.com)
 * @link http://www.isthe.com/chongo/tech/comp/fnv/index.html
 */
public final class FNVHash {

    private static final long FNV_64_INIT = 0xcbf29ce484222325L;
    private static final long FNV_64_PRIME = 0x100000001b3L;

    private static final int FNV_32_INIT = 0x811c9dc5;
    private static final int FNV_32_PRIME = 0x01000193;

    public FNVHash() {}

    public static int hash32(final byte[] k) {
        int rv = FNV_32_INIT;
        final int len = k.length;
        for(int i = 0; i < len; i++) {
            rv ^= k[i];
            rv *= FNV_32_PRIME;
        }
        return rv;
    }

    public static long hash64(final byte[] k) {
        long rv = FNV_64_INIT;
        final int len = k.length;
        for(int i = 0; i < len; i++) {
            rv ^= k[i];
            rv *= FNV_64_PRIME;
        }
        return rv;
    }

    public static int hash32(final String k) {
        int rv = FNV_32_INIT;
        final int len = k.length();
        for(int i = 0; i < len; i++) {
            rv ^= k.charAt(i);
            rv *= FNV_32_PRIME;
        }
        return rv;
    }

    public static long hash64(final String k) {
        long rv = FNV_64_INIT;
        final int len = k.length();
        for(int i = 0; i < len; i++) {
            rv ^= k.charAt(i);
            rv *= FNV_64_PRIME;
        }
        return rv;
    }

}

   
    
    
    
    
    
  








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