001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 018package org.apache.commons.rng.core.source64; 019 020/** 021 * A fast all-purpose 64-bit generator. 022 * 023 * <p>This is a member of the Xor-Shift-Rotate family of generators. Memory footprint is 256 bits 024 * and the period is 2<sup>256</sup>-1.</p> 025 * 026 * @see <a href="http://xoshiro.di.unimi.it/xoshiro256starstar.c">Original source code</a> 027 * @see <a href="http://xoshiro.di.unimi.it/">xorshiro / xoroshiro generators</a> 028 * @since 1.3 029 */ 030public class XoShiRo256PlusPlus extends AbstractXoShiRo256 { 031 /** 032 * Creates a new instance. 033 * 034 * @param seed Initial seed. 035 * If the length is larger than 4, only the first 4 elements will 036 * be used; if smaller, the remaining elements will be automatically 037 * set. A seed containing all zeros will create a non-functional generator. 038 */ 039 public XoShiRo256PlusPlus(long[] seed) { 040 super(seed); 041 } 042 043 /** 044 * Creates a new instance using a 4 element seed. 045 * A seed containing all zeros will create a non-functional generator. 046 * 047 * @param seed0 Initial seed element 0. 048 * @param seed1 Initial seed element 1. 049 * @param seed2 Initial seed element 2. 050 * @param seed3 Initial seed element 3. 051 */ 052 public XoShiRo256PlusPlus(long seed0, long seed1, long seed2, long seed3) { 053 super(seed0, seed1, seed2, seed3); 054 } 055 056 /** 057 * Creates a copy instance. 058 * 059 * @param source Source to copy. 060 */ 061 protected XoShiRo256PlusPlus(XoShiRo256PlusPlus source) { 062 super(source); 063 } 064 065 /** {@inheritDoc} */ 066 @Override 067 protected long nextOutput() { 068 return Long.rotateLeft(state0 + state3, 23) + state0; 069 } 070 071 /** {@inheritDoc} */ 072 @Override 073 protected XoShiRo256PlusPlus copy() { 074 // This exists to ensure the jump function performed in the super class returns 075 // the correct class type. It should not be public. 076 return new XoShiRo256PlusPlus(this); 077 } 078}