1/*
2 * Copyright (C) 2008 The Guava Authors
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.google.common.collect;
18
19import com.google.common.annotations.GwtCompatible;
20
21/**
22 * Static methods for implementing hash-based collections.
23 *
24 * @author Kevin Bourrillion
25 * @author Jesse Wilson
26 */
27@GwtCompatible
28final class Hashing {
29  private Hashing() {}
30
31  /*
32   * This method was written by Doug Lea with assistance from members of JCP
33   * JSR-166 Expert Group and released to the public domain, as explained at
34   * http://creativecommons.org/licenses/publicdomain
35   *
36   * As of 2010/06/11, this method is identical to the (package private) hash
37   * method in OpenJDK 7's java.util.HashMap class.
38   */
39  static int smear(int hashCode) {
40    hashCode ^= (hashCode >>> 20) ^ (hashCode >>> 12);
41    return hashCode ^ (hashCode >>> 7) ^ (hashCode >>> 4);
42  }
43}
44