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 generator.
022 *
023 * <p>This is a member of the Xor-Shift-Rotate family of generators. Memory footprint is 512 bits
024 * and the period is 2<sup>512</sup>-1. Speed is expected to be slower than
025 * {@link XoShiRo256StarStar}.</p>
026 *
027 * @see <a href="http://xoshiro.di.unimi.it/xoshiro512plusplus.c">Original source code</a>
028 * @see <a href="http://xoshiro.di.unimi.it/">xorshiro / xoroshiro generators</a>
029 * @since 1.3
030 */
031public class XoShiRo512PlusPlus extends AbstractXoShiRo512 {
032    /**
033     * Creates a new instance.
034     *
035     * @param seed Initial seed.
036     * If the length is larger than 8, only the first 8 elements will
037     * be used; if smaller, the remaining elements will be automatically
038     * set. A seed containing all zeros will create a non-functional generator.
039     */
040    public XoShiRo512PlusPlus(long[] seed) {
041        super(seed);
042    }
043
044    /**
045     * Creates a new instance using an 8 element seed.
046     * A seed containing all zeros will create a non-functional generator.
047     *
048     * @param seed0 Initial seed element 0.
049     * @param seed1 Initial seed element 1.
050     * @param seed2 Initial seed element 2.
051     * @param seed3 Initial seed element 3.
052     * @param seed4 Initial seed element 4.
053     * @param seed5 Initial seed element 5.
054     * @param seed6 Initial seed element 6.
055     * @param seed7 Initial seed element 7.
056     */
057    public XoShiRo512PlusPlus(long seed0, long seed1, long seed2, long seed3,
058                              long seed4, long seed5, long seed6, long seed7) {
059        super(seed0, seed1, seed2, seed3, seed4, seed5, seed6, seed7);
060    }
061
062    /**
063     * Creates a copy instance.
064     *
065     * @param source Source to copy.
066     */
067    protected XoShiRo512PlusPlus(XoShiRo512PlusPlus source) {
068        super(source);
069    }
070
071    /** {@inheritDoc} */
072    @Override
073    protected long nextOutput() {
074        return Long.rotateLeft(state0 + state2, 17) + state2;
075    }
076
077    /** {@inheritDoc} */
078    @Override
079    protected XoShiRo512PlusPlus copy() {
080        // This exists to ensure the jump function performed in the super class returns
081        // the correct class type. It should not be public.
082        return new XoShiRo512PlusPlus(this);
083    }
084}