Android examples for java.security:Hash
Hash every element uniformly using the Modified Bernstein hash.
/*// w w w . j av a 2 s. c o m * Copyright (C) 2014 The Android Open Source Project * * 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 com.java2s; public class Main { /** * Hash every element uniformly using the Modified Bernstein hash. * * <p>Useful to implement a {@link Object#hashCode} for uniformly distributed data.</p> * * @param array a non-{@code null} array of integers * * @return the numeric hash code */ public static int hashCode(int... array) { if (array == null) { return 0; } /* * Note that we use 31 here instead of 33 since it's preferred in Effective Java * and used elsewhere in the runtime (e.g. Arrays#hashCode) * * That being said 33 and 31 are nearly identical in terms of their usefulness * according to http://svn.apache.org/repos/asf/apr/apr/trunk/tables/apr_hash.c */ int h = 1; for (int x : array) { // Strength reduction; in case the compiler has illusions about divisions being faster h = ((h << 5) - h) ^ x; // (h * 31) XOR x } return h; } /** * Hash every element uniformly using the Modified Bernstein hash. * * <p>Useful to implement a {@link Object#hashCode} for uniformly distributed data.</p> * * @param array a non-{@code null} array of floats * * @return the numeric hash code */ public static int hashCode(float... array) { if (array == null) { return 0; } int h = 1; for (float f : array) { int x = Float.floatToIntBits(f); h = ((h << 5) - h) ^ x; // (h * 31) XOR x } return h; } }