--- a/src/java.base/share/classes/java/util/Xoshiro256StarStar.java Thu Jun 27 16:46:44 2019 -0300
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,285 +0,0 @@
-/*
- * Copyright (c) 2013, 2019, Oracle and/or its affiliates. All rights reserved.
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This code is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation. Oracle designates this
- * particular file as subject to the "Classpath" exception as provided
- * by Oracle in the LICENSE file that accompanied this code.
- *
- * This code is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
- * or visit www.oracle.com if you need additional information or have any
- * questions.
- */
-package java.util;
-
-import java.math.BigInteger;
-import java.util.concurrent.atomic.AtomicLong;
-
-/**
- * A generator of uniform pseudorandom values applicable for use in
- * (among other contexts) isolated parallel computations that may
- * generate subtasks. Class {@code Xoshiro256StarStar} implements
- * interfaces {@link java.util.Rng} and {@link java.util.LeapableRng},
- * and therefore supports methods for producing pseudorandomly chosen
- * numbers of type {@code int}, {@code long}, {@code float}, and {@code double}
- * as well as creating new {@code Xoshiro256StarStar} objects
- * by "jumping" or "leaping".
- *
- * <p>Series of generated values pass the TestU01 BigCrush and PractRand test suites
- * that measure independence and uniformity properties of random number generators.
- * (Most recently validated with
- * <a href="http://simul.iro.umontreal.ca/testu01/tu01.html">version 1.2.3 of TestU01</a>
- * and <a href="http://pracrand.sourceforge.net">version 0.90 of PractRand</a>.
- * Note that TestU01 BigCrush was used to test not only values produced by the {@code nextLong()}
- * method but also the result of bit-reversing each value produced by {@code nextLong()}.)
- * These tests validate only the methods for certain
- * types and ranges, but similar properties are expected to hold, at
- * least approximately, for others as well.
- *
- * <p>The class {@code Xoshiro256StarStar} uses the {@code xoshiro256} algorithm,
- * version 1.0 (parameters 17, 45), with the "**" scrambler (a mixing function).
- * Its state consists of four {@code long} fields {@code x0}, {@code x1}, {@code x2},
- * and {@code x3}, which can take on any values provided that they are not all zero.
- * The period of this generator is 2<sup>256</sup>-1.
- *
- * <p>The 64-bit values produced by the {@code nextLong()} method are equidistributed.
- * To be precise, over the course of the cycle of length 2<sup>256</sup>-1,
- * each nonzero {@code long} value is generated 2<sup>192</sup> times,
- * but the value 0 is generated only 2<sup>192</sup>-1 times.
- * The values produced by the {@code nextInt()}, {@code nextFloat()}, and {@code nextDouble()}
- * methods are likewise equidistributed.
- *
- * <p>In fact, the 64-bit values produced by the {@code nextLong()} method are 4-equidistributed.
- * To be precise: consider the (overlapping) length-4 subsequences of the cycle of 64-bit
- * values produced by {@code nextLong()} (assuming no other methods are called that would
- * affect the state). There are 2<sup>256</sup>-1 such subsequences, and each subsequence,
- * which consists of 4 64-bit values, can have one of 2<sup>256</sup> values. Of those
- * 2<sup>256</sup> subsequence values, each one is generated exactly once over the course
- * of the entire cycle, except that the subsequence (0, 0, 0, 0) never appears.
- * The values produced by the {@code nextInt()}, {@code nextFloat()}, and {@code nextDouble()}
- * methods are likewise 4-equidistributed, but note that that the subsequence (0, 0, 0, 0)
- * can also appear (but occurring somewhat less frequently than all other subsequences),
- * because the values produced by those methods have fewer than 64 randomly chosen bits.
- *
- * <p>Instances {@code Xoshiro256StarStar} are <em>not</em> thread-safe.
- * They are designed to be used so that each thread as its own instance.
- * The methods {@link #jump} and {@link #leap} and {@link #jumps} and {@link #leaps}
- * can be used to construct new instances of {@code Xoshiro256StarStar} that traverse
- * other parts of the state cycle.
- *
- * <p>Instances of {@code Xoshiro256StarStar} are not cryptographically
- * secure. Consider instead using {@link java.security.SecureRandom}
- * in security-sensitive applications. Additionally,
- * default-constructed instances do not use a cryptographically random
- * seed unless the {@linkplain System#getProperty system property}
- * {@code java.util.secureRandomSeed} is set to {@code true}.
- *
- * @author Guy Steele
- * @since 1.9
- */
-public final class Xoshiro256StarStar implements LeapableRng {
-
- /*
- * Implementation Overview.
- *
- * This is an implementation of the xoroshiro128** algorithm written
- * in 2018 by David Blackman and Sebastiano Vigna (vigna@acm.org).
- * See http://xoshiro.di.unimi.it and these two papers:
- *
- * Sebastiano Vigna. 2016. An Experimental Exploration of Marsaglia's
- * xorshift Generators, Scrambled. ACM Transactions on Mathematical
- * Software 42, 4, Article 30 (June 2016), 23 pages.
- * https://doi.org/10.1145/2845077
- *
- * David Blackman and Sebastiano Vigna. 2018. Scrambled Linear
- * Pseudorandom Number Generators. Computing Research Repository (CoRR).
- * http://arxiv.org/abs/1805.01407
- *
- * The jump operation moves the current generator forward by 2*128
- * steps; this has the same effect as calling nextLong() 2**128
- * times, but is much faster. Similarly, the leap operation moves
- * the current generator forward by 2*192 steps; this has the same
- * effect as calling nextLong() 2**192 times, but is much faster.
- * The copy method may be used to make a copy of the current
- * generator. Thus one may repeatedly and cumulatively copy and
- * jump to produce a sequence of generators whose states are well
- * spaced apart along the overall state cycle (indeed, the jumps()
- * and leaps() methods each produce a stream of such generators).
- * The generators can then be parceled out to other threads.
- *
- * File organization: First static fields, then instance
- * fields, then constructors, then instance methods.
- */
-
- /* ---------------- static fields ---------------- */
-
- /**
- * The seed generator for default constructors.
- */
- private static final AtomicLong defaultGen = new AtomicLong(RngSupport.initialSeed());
-
- /*
- * The period of this generator, which is 2**256 - 1.
- */
- private static final BigInteger thePeriod =
- BigInteger.ONE.shiftLeft(256).subtract(BigInteger.ONE);
-
- /* ---------------- instance fields ---------------- */
-
- /**
- * The per-instance state.
- * At least one of the four fields x0, x1, x2, and x3 must be nonzero.
- */
- private long x0, x1, x2, x3;
-
- /* ---------------- constructors ---------------- */
-
- /**
- * Basic constructor that initializes all fields from parameters.
- * It then adjusts the field values if necessary to ensure that
- * all constraints on the values of fields are met.
- *
- * @param x0 first word of the initial state
- * @param x1 second word of the initial state
- * @param x2 third word of the initial state
- * @param x3 fourth word of the initial state
- */
- public Xoshiro256StarStar(long x0, long x1, long x2, long x3) {
- this.x0 = x0;
- this.x1 = x1;
- this.x2 = x2;
- this.x3 = x3;
- // If x0, x1, x2, and x3 are all zero, we must choose nonzero values.
- if ((x0 | x1 | x2 | x3) == 0) {
- // At least three of the four values generated here will be nonzero.
- this.x0 = RngSupport.mixStafford13(x0 += RngSupport.GOLDEN_RATIO_64);
- this.x1 = (x0 += RngSupport.GOLDEN_RATIO_64);
- this.x2 = (x0 += RngSupport.GOLDEN_RATIO_64);
- this.x3 = (x0 += RngSupport.GOLDEN_RATIO_64);
- }
- }
-
- /**
- * Creates a new instance of {@code Xoshiro256StarStar} using the
- * specified {@code long} value as the initial seed. Instances of
- * {@code Xoshiro256StarStar} created with the same seed in the same
- * program generate identical sequences of values.
- *
- * @param seed the initial seed
- */
- public Xoshiro256StarStar(long seed) {
- // Using a value with irregularly spaced 1-bits to xor the seed
- // argument tends to improve "pedestrian" seeds such as 0 or
- // other small integers. We may as well use SILVER_RATIO_64.
- //
- // The x values are then filled in as if by a SplitMix PRNG with
- // GOLDEN_RATIO_64 as the gamma value and Stafford13 as the mixer.
- this(RngSupport.mixStafford13(seed ^= RngSupport.SILVER_RATIO_64),
- RngSupport.mixStafford13(seed += RngSupport.GOLDEN_RATIO_64),
- RngSupport.mixStafford13(seed += RngSupport.GOLDEN_RATIO_64),
- RngSupport.mixStafford13(seed + RngSupport.GOLDEN_RATIO_64));
- }
-
- /**
- * Creates a new instance of {@code Xoshiro256StarStar} that is likely to
- * generate sequences of values that are statistically independent
- * of those of any other instances in the current program execution,
- * but may, and typically does, vary across program invocations.
- */
- public Xoshiro256StarStar() {
- // Using GOLDEN_RATIO_64 here gives us a good Weyl sequence of values.
- this(defaultGen.getAndAdd(RngSupport.GOLDEN_RATIO_64));
- }
-
- /**
- * Creates a new instance of {@code Xoshiro256StarStar} using the specified array of
- * initial seed bytes. Instances of {@code Xoshiro256StarStar} created with the same
- * seed array in the same program execution generate identical sequences of values.
- *
- * @param seed the initial seed
- */
- public Xoshiro256StarStar(byte[] seed) {
- // Convert the seed to 4 long values, which are not all zero.
- long[] data = RngSupport.convertSeedBytesToLongs(seed, 4, 4);
- long x0 = data[0], x1 = data[1], x2 = data[2], x3 = data[3];
- this.x0 = x0;
- this.x1 = x1;
- this.x2 = x2;
- this.x3 = x3;
- }
-
- /* ---------------- public methods ---------------- */
-
- public Xoshiro256StarStar copy() { return new Xoshiro256StarStar(x0, x1, x2, x3); }
-
- /**
- * Returns a pseudorandom {@code long} value.
- *
- * @return a pseudorandom {@code long} value
- */
-
- public long nextLong() {
- final long z = x0;
- long q0 = x0, q1 = x1, q2 = x2, q3 = x3;
- { long t = q1 << 17; q2 ^= q0; q3 ^= q1; q1 ^= q2; q0 ^= q3; q2 ^= t; q3 = Long.rotateLeft(q3, 45); } // xoshiro256 1.0
- x0 = q0; x1 = q1; x2 = q2; x3 = q3;
- return Long.rotateLeft(z * 5, 7) * 9; // "starstar" mixing function
- }
-
- public BigInteger period() { return thePeriod; }
-
-
- public double defaultJumpDistance() { return 0x1.0p64; }
- public double defaultLeapDistance() { return 0x1.0p96; }
-
- private static final long[] JUMP_TABLE = {
- 0x180ec6d33cfd0abaL, 0xd5a61266f0c9392cL, 0xa9582618e03fc9aaL, 0x39abdc4529b1661cL };
-
- private static final long[] LEAP_TABLE = {
- 0x76e15d3efefdcbbfL, 0xc5004e441c522fb3L, 0x77710069854ee241L, 0x39109bb02acbe635L };
-
-/* This is the jump function for the generator. It is equivalent
- to 2**128 calls to next(); it can be used to generate 2**128
- non-overlapping subsequences for parallel computations. */
-
- public void jump() { jumpAlgorithm(JUMP_TABLE); }
-
-/* This is the long-jump function for the generator. It is equivalent to
- 2**192 calls to next(); it can be used to generate 2**64 starting points,
- from each of which jump() will generate 2**64 non-overlapping
- subsequences for parallel distributed computations. */
-
- public void leap() { jumpAlgorithm(LEAP_TABLE); }
-
- private void jumpAlgorithm(long[] table) {
- long s0 = 0, s1 = 0, s2 = 0, s3 = 0;
- for (int i = 0; i < table.length; i++) {
- for (int b = 0; b < 64; b++) {
- if ((table[i] & (1L << b)) != 0) {
- s0 ^= x0;
- s1 ^= x1;
- s2 ^= x2;
- s3 ^= x3;
- }
- nextLong();
- }
- x0 = s0;
- x1 = s1;
- x2 = s2;
- x3 = s3;
- }
- }
-
-}