Hashing.java

/*
 * Copyright (C) 2008 The Guava Authors
 *
 * 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.
 */

package org.glassfish.jersey.internal.guava;

/**
 * Static methods for implementing hash-based collections.
 *
 * @author Kevin Bourrillion
 * @author Jesse Wilson
 * @author Austin Appleby
 */
final class Hashing {
    private static final int C1 = 0xcc9e2d51;
    private static final int C2 = 0x1b873593;

    private Hashing() {
    }

    /*
     * This method was rewritten in Java from an intermediate step of the Murmur hash function in
     * http://code.google.com/p/smhasher/source/browse/trunk/MurmurHash3.cpp, which contained the
     * following header:
     *
     * MurmurHash3 was written by Austin Appleby, and is placed in the public domain. The author
     * hereby disclaims copyright to this source code.
     */
    static int smear(int hashCode) {
        return C2 * Integer.rotateLeft(hashCode * C1, 15);
    }

}