Add sources for API 35
Downloaded from https://dl.google.com/android/repository/source-35_r01.zip
using SdkManager in Studio
Test: None
Change-Id: I83f78aa820b66edfdc9f8594d17bc7b6cacccec1
diff --git a/android-35/jdk/random/L64X128StarStarRandom.java b/android-35/jdk/random/L64X128StarStarRandom.java
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+/*
+ * Copyright (c) 2021, 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 jdk.random;
+
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.random.RandomGenerator;
+import jdk.internal.util.random.RandomSupport;
+import jdk.internal.util.random.RandomSupport.AbstractSplittableWithBrineGenerator;
+import jdk.internal.util.random.RandomSupport.RandomGeneratorProperties;
+
+/**
+ * A "splittable" pseudorandom number generator (PRNG) whose period
+ * is roughly 2<sup>192</sup>. Class {@link L64X128StarStarRandom} implements
+ * interfaces {@link RandomGenerator} and {@link SplittableGenerator},
+ * and therefore supports methods for producing pseudorandomly chosen
+ * values of type {@code int}, {@code long}, {@code float}, {@code double},
+ * and {@code boolean} (and for producing streams of pseudorandomly chosen
+ * numbers of type {@code int}, {@code long}, and {@code double}),
+ * as well as methods for creating new split-off {@link L64X128StarStarRandom}
+ * objects or streams of such objects.
+ *
+ * <p>The {@link L64X128StarStarRandom} algorithm is a specific member of
+ * the LXM family of algorithms for pseudorandom number generators;
+ * for more information, see the documentation for package
+ * {@link jdk.random}. Each instance of {@link L64X128StarStarRandom}
+ * has 192 bits of state plus one 64-bit instance-specific parameter.
+ *
+ * <p>If two instances of {@link L64X128StarStarRandom} are created with
+ * the same seed within the same program execution, and the same
+ * sequence of method calls is made for each, they will generate and
+ * return identical sequences of values.
+ *
+ * <p>As with {@link java.util.SplittableRandom}, instances of
+ * {@link L64X128StarStarRandom} are <em>not</em> thread-safe. They are
+ * designed to be split, not shared, across threads (see the {@link #split}
+ * method). For example, a {@link java.util.concurrent.ForkJoinTask}
+ * fork/join-style computation using random numbers might include a
+ * construction of the form
+ * {@code new Subtask(someL64X128StarStarRandom.split()).fork()}.
+ *
+ * <p>This class provides additional methods for generating random
+ * streams, that employ the above techniques when used in
+ * {@code stream.parallel()} mode.
+ *
+ * <p>Instances of {@link L64X128StarStarRandom} 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}.
+ *
+ * @since 17
+ *
+ */
+@RandomGeneratorProperties(
+ name = "L64X128StarStarRandom",
+ group = "LXM",
+ i = 128, j = 1, k = 64,
+ equidistribution = 2
+)
+public final class L64X128StarStarRandom extends AbstractSplittableWithBrineGenerator {
+
+ /*
+ * Implementation Overview.
+ *
+ * The split operation uses the current generator to choose four new 64-bit
+ * long values that are then used to initialize the parameter `a` and the
+ * state variables `s`, `x0`, and `x1` for a newly constructed generator.
+ *
+ * With extremely high probability, no two generators so chosen
+ * will have the same `a` parameter, and testing has indicated
+ * that the values generated by two instances of {@link L64X128StarStarRandom}
+ * will be (approximately) independent if have different values for `a`.
+ *
+ * The default (no-argument) constructor, in essence, uses
+ * "defaultGen" to generate four new 64-bit values for the same
+ * purpose. Multiple generators created in this way will certainly
+ * differ in their `a` parameters. The defaultGen state must be accessed
+ * in a thread-safe manner, so we use an AtomicLong to represent
+ * this state. To bootstrap the defaultGen, we start off using a
+ * seed based on current time unless the
+ * java.util.secureRandomSeed property is set. This serves as a
+ * slimmed-down (and insecure) variant of SecureRandom that also
+ * avoids stalls that may occur when using /dev/random.
+ *
+ * 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(RandomSupport.initialSeed());
+
+ /*
+ * Multiplier used in the LCG portion of the algorithm.
+ * Chosen based on research by Sebastiano Vigna and Guy Steele (2019).
+ * The spectral scores for dimensions 2 through 8 for the multiplier 0xd1342543de82ef95
+ * are [0.958602, 0.937479, 0.870757, 0.822326, 0.820405, 0.813065, 0.760215].
+ */
+
+ private static final long M = 0xd1342543de82ef95L;
+
+ /* ---------------- instance fields ---------------- */
+
+ /**
+ * The parameter that is used as an additive constant for the LCG.
+ * Must be odd.
+ */
+ private final long a;
+
+ /**
+ * The per-instance state: s for the LCG; x0 and x1 for the XBG.
+ * At least one of x0 and x1 must be nonzero.
+ */
+ private long s, x0, x1;
+
+ /* ---------------- 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 a additive parameter for the LCG
+ * @param s initial state for the LCG
+ * @param x0 first word of the initial state for the XBG
+ * @param x1 second word of the initial state for the XBG
+ */
+ public L64X128StarStarRandom(long a, long s, long x0, long x1) {
+ // Force a to be odd.
+ this.a = a | 1;
+ this.s = s;
+ this.x0 = x0;
+ this.x1 = x1;
+ // If x0 and x1 are both zero, we must choose nonzero values.
+ if ((x0 | x1) == 0) {
+ long v = s;
+ // At least one of the two values generated here will be nonzero.
+ this.x0 = RandomSupport.mixStafford13(v += RandomSupport.GOLDEN_RATIO_64);
+ this.x1 = RandomSupport.mixStafford13(v + RandomSupport.GOLDEN_RATIO_64);
+ }
+ }
+
+ /**
+ * Creates a new instance of {@link L64X128StarStarRandom} using the
+ * specified {@code long} value as the initial seed. Instances of
+ * {@link L64X128StarStarRandom} created with the same seed in the same
+ * program generate identical sequences of values.
+ *
+ * @param seed the initial seed
+ */
+ public L64X128StarStarRandom(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 seed is hashed by mixMurmur64 to produce the `a` parameter.
+ // The seed is hashed by mixStafford13 to produce the initial `x0`,
+ // which will then be used to produce the first generated value.
+ // Then x1 is filled in as if by a SplitMix PRNG with
+ // GOLDEN_RATIO_64 as the gamma value and mixStafford13 as the mixer.
+ this(RandomSupport.mixMurmur64(seed ^= RandomSupport.SILVER_RATIO_64),
+ 1,
+ RandomSupport.mixStafford13(seed),
+ RandomSupport.mixStafford13(seed + RandomSupport.GOLDEN_RATIO_64));
+ }
+
+ /**
+ * Creates a new instance of {@link L64X128StarStarRandom} 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 L64X128StarStarRandom() {
+ // Using GOLDEN_RATIO_64 here gives us a good Weyl sequence of values.
+ this(defaultGen.getAndAdd(RandomSupport.GOLDEN_RATIO_64));
+ }
+
+ /**
+ * Creates a new instance of {@link L64X128StarStarRandom} using the specified array of
+ * initial seed bytes. Instances of {@link L64X128StarStarRandom} created with the same
+ * seed array in the same program execution generate identical sequences of values.
+ *
+ * @param seed the initial seed
+ */
+ public L64X128StarStarRandom(byte[] seed) {
+ // Convert the seed to 4 long values, of which the last 2 are not all zero.
+ long[] data = RandomSupport.convertSeedBytesToLongs(seed, 4, 2);
+ long a = data[0], s = data[1], x0 = data[2], x1 = data[3];
+ // Force a to be odd.
+ this.a = a | 1;
+ this.s = s;
+ this.x0 = x0;
+ this.x1 = x1;
+ }
+
+ /* ---------------- public methods ---------------- */
+
+ @Override
+ public SplittableGenerator split(SplittableGenerator source, long brine) {
+ // Pick a new instance "at random", but use the brine for `a`.
+ return new L64X128StarStarRandom(brine << 1, source.nextLong(),
+ source.nextLong(), source.nextLong());
+ }
+
+ @Override
+ public long nextLong() {
+ // Compute the result based on current state information
+ // (this allows the computation to be overlapped with state update).
+ final long result = Long.rotateLeft((s + x0) * 5, 7) * 9; // "starstar" scrambler
+
+ // Update the LCG subgenerator
+ s = M * s + a;
+
+ // Update the XBG subgenerator
+ long q0 = x0, q1 = x1;
+ { // xoroshiro128v1_0
+ q1 ^= q0;
+ q0 = Long.rotateLeft(q0, 24);
+ q0 = q0 ^ q1 ^ (q1 << 16);
+ q1 = Long.rotateLeft(q1, 37);
+ }
+ x0 = q0; x1 = q1;
+
+ return result;
+ }
+
+}
