--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/java/util/SplittableRandom.java Mon Aug 26 22:55:03 2013 +0200
@@ -0,0 +1,1002 @@
+/*
+ * Copyright (c) 2013, 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.security.SecureRandom;
+import java.net.InetAddress;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.function.IntConsumer;
+import java.util.function.LongConsumer;
+import java.util.function.DoubleConsumer;
+import java.util.stream.StreamSupport;
+import java.util.stream.IntStream;
+import java.util.stream.LongStream;
+import java.util.stream.DoubleStream;
+
+/**
+ * A generator of uniform pseudorandom values applicable for use in
+ * (among other contexts) isolated parallel computations that may
+ * generate subtasks. Class {@code SplittableRandom} supports methods for
+ * producing pseudorandom numbers of type {@code int}, {@code long},
+ * and {@code double} with similar usages as for class
+ * {@link java.util.Random} but differs in the following ways:
+ *
+ * <ul>
+ *
+ * <li>Series of generated values pass the DieHarder suite testing
+ * independence and uniformity properties of random number generators.
+ * (Most recently validated with <a
+ * href="http://www.phy.duke.edu/~rgb/General/dieharder.php"> version
+ * 3.31.1</a>.) 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. The <em>period</em>
+ * (length of any series of generated values before it repeats) is at
+ * least 2<sup>64</sup>. </li>
+ *
+ * <li> Method {@link #split} constructs and returns a new
+ * SplittableRandom instance that shares no mutable state with the
+ * current instance. However, with very high probability, the
+ * values collectively generated by the two objects have the same
+ * statistical properties as if the same quantity of values were
+ * generated by a single thread using a single {@code
+ * SplittableRandom} object. </li>
+ *
+ * <li>Instances of SplittableRandom are <em>not</em> thread-safe.
+ * They are designed to be split, not shared, across threads. 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(aSplittableRandom.split()).fork()}.
+ *
+ * <li>This class provides additional methods for generating random
+ * streams, that employ the above techniques when used in {@code
+ * stream.parallel()} mode.</li>
+ *
+ * </ul>
+ *
+ * <p>Instances of {@code SplittableRandom} 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
+ * @author Doug Lea
+ * @since 1.8
+ */
+public final class SplittableRandom {
+
+ /*
+ * Implementation Overview.
+ *
+ * This algorithm was inspired by the "DotMix" algorithm by
+ * Leiserson, Schardl, and Sukha "Deterministic Parallel
+ * Random-Number Generation for Dynamic-Multithreading Platforms",
+ * PPoPP 2012, as well as those in "Parallel random numbers: as
+ * easy as 1, 2, 3" by Salmon, Morae, Dror, and Shaw, SC 2011. It
+ * differs mainly in simplifying and cheapening operations.
+ *
+ * The primary update step (method nextSeed()) is to add a
+ * constant ("gamma") to the current (64 bit) seed, forming a
+ * simple sequence. The seed and the gamma values for any two
+ * SplittableRandom instances are highly likely to be different.
+ *
+ * Methods nextLong, nextInt, and derivatives do not return the
+ * sequence (seed) values, but instead a hash-like bit-mix of
+ * their bits, producing more independently distributed sequences.
+ * For nextLong, the mix64 bit-mixing function computes the same
+ * value as the "64-bit finalizer" function in Austin Appleby's
+ * MurmurHash3 algorithm. See
+ * http://code.google.com/p/smhasher/wiki/MurmurHash3 , which
+ * comments: "The constants for the finalizers were generated by a
+ * simple simulated-annealing algorithm, and both avalanche all
+ * bits of 'h' to within 0.25% bias." The mix32 function is
+ * equivalent to (int)(mix64(seed) >>> 32), but faster because it
+ * omits a step that doesn't contribute to result.
+ *
+ * The split operation uses the current generator to form the seed
+ * and gamma for another SplittableRandom. To conservatively
+ * avoid potential correlations between seed and value generation,
+ * gamma selection (method nextGamma) uses the "Mix13" constants
+ * for MurmurHash3 described by David Stafford
+ * (http://zimbry.blogspot.com/2011/09/better-bit-mixing-improving-on.html)
+ * To avoid potential weaknesses in bit-mixing transformations, we
+ * restrict gammas to odd values with at least 12 and no more than
+ * 52 bits set. Rather than rejecting candidates with too few or
+ * too many bits set, method nextGamma flips some bits (which has
+ * the effect of mapping at most 4 to any given gamma value).
+ * This reduces the effective set of 64bit odd gamma values by
+ * about 2<sup>14</sup>, a very tiny percentage, and serves as an
+ * automated screening for sequence constant selection that is
+ * left as an empirical decision in some other hashing and crypto
+ * algorithms.
+ *
+ * The resulting generator thus transforms a sequence in which
+ * (typically) many bits change on each step, with an inexpensive
+ * mixer with good (but less than cryptographically secure)
+ * avalanching.
+ *
+ * The default (no-argument) constructor, in essence, invokes
+ * split() for a common "seeder" SplittableRandom. Unlike other
+ * cases, this split must be performed in a thread-safe manner, so
+ * we use an AtomicLong to represent the seed rather than use an
+ * explicit SplittableRandom. To bootstrap the seeder, we start
+ * off using a seed based on current time and host 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.
+ *
+ * It is a relatively simple matter to apply the basic design here
+ * to use 128 bit seeds. However, emulating 128bit arithmetic and
+ * carrying around twice the state add more overhead than appears
+ * warranted for current usages.
+ *
+ * File organization: First the non-public methods that constitute
+ * the main algorithm, then the main public methods, followed by
+ * some custom spliterator classes needed for stream methods.
+ */
+
+ /**
+ * The initial gamma value for (unsplit) SplittableRandoms. Must
+ * be odd with at least 12 and no more than 52 bits set. Currently
+ * set to the golden ratio scaled to 64bits.
+ */
+ private static final long INITIAL_GAMMA = 0x9e3779b97f4a7c15L;
+
+ /**
+ * The least non-zero value returned by nextDouble(). This value
+ * is scaled by a random value of 53 bits to produce a result.
+ */
+ private static final double DOUBLE_UNIT = 1.0 / (1L << 53);
+
+ /**
+ * The seed. Updated only via method nextSeed.
+ */
+ private long seed;
+
+ /**
+ * The step value.
+ */
+ private final long gamma;
+
+ /**
+ * Internal constructor used by all others except default constructor.
+ */
+ private SplittableRandom(long seed, long gamma) {
+ this.seed = seed;
+ this.gamma = gamma;
+ }
+
+ /**
+ * Computes MurmurHash3 64bit mix function.
+ */
+ private static long mix64(long z) {
+ z = (z ^ (z >>> 33)) * 0xff51afd7ed558ccdL;
+ z = (z ^ (z >>> 33)) * 0xc4ceb9fe1a85ec53L;
+ return z ^ (z >>> 33);
+ }
+
+ /**
+ * Returns the 32 high bits of mix64(z) as int.
+ */
+ private static int mix32(long z) {
+ z = (z ^ (z >>> 33)) * 0xff51afd7ed558ccdL;
+ return (int)(((z ^ (z >>> 33)) * 0xc4ceb9fe1a85ec53L) >>> 32);
+ }
+
+ /**
+ * Returns the gamma value to use for a new split instance.
+ */
+ private static long nextGamma(long z) {
+ z = (z ^ (z >>> 30)) * 0xbf58476d1ce4e5b9L; // Stafford "Mix13"
+ z = (z ^ (z >>> 27)) * 0x94d049bb133111ebL;
+ z = (z ^ (z >>> 31)) | 1L; // force to be odd
+ int n = Long.bitCount(z); // ensure enough 0 and 1 bits
+ return (n < 12 || n > 52) ? z ^ 0xaaaaaaaaaaaaaaaaL : z;
+ }
+
+ /**
+ * Adds gamma to seed.
+ */
+ private long nextSeed() {
+ return seed += gamma;
+ }
+
+ /**
+ * The seed generator for default constructors.
+ */
+ private static final AtomicLong seeder = new AtomicLong(initialSeed());
+
+ private static long initialSeed() {
+ String pp = java.security.AccessController.doPrivileged(
+ new sun.security.action.GetPropertyAction(
+ "java.util.secureRandomSeed"));
+ if (pp != null && pp.equalsIgnoreCase("true")) {
+ byte[] seedBytes = java.security.SecureRandom.getSeed(8);
+ long s = (long)(seedBytes[0]) & 0xffL;
+ for (int i = 1; i < 8; ++i)
+ s = (s << 8) | ((long)(seedBytes[i]) & 0xffL);
+ return s;
+ }
+ int hh = 0; // hashed host address
+ try {
+ hh = InetAddress.getLocalHost().hashCode();
+ } catch (Exception ignore) {
+ }
+ return (mix64((((long)hh) << 32) ^ System.currentTimeMillis()) ^
+ mix64(System.nanoTime()));
+ }
+
+ // IllegalArgumentException messages
+ static final String BadBound = "bound must be positive";
+ static final String BadRange = "bound must be greater than origin";
+ static final String BadSize = "size must be non-negative";
+
+ /*
+ * Internal versions of nextX methods used by streams, as well as
+ * the public nextX(origin, bound) methods. These exist mainly to
+ * avoid the need for multiple versions of stream spliterators
+ * across the different exported forms of streams.
+ */
+
+ /**
+ * The form of nextLong used by LongStream Spliterators. If
+ * origin is greater than bound, acts as unbounded form of
+ * nextLong, else as bounded form.
+ *
+ * @param origin the least value, unless greater than bound
+ * @param bound the upper bound (exclusive), must not equal origin
+ * @return a pseudorandom value
+ */
+ final long internalNextLong(long origin, long bound) {
+ /*
+ * Four Cases:
+ *
+ * 1. If the arguments indicate unbounded form, act as
+ * nextLong().
+ *
+ * 2. If the range is an exact power of two, apply the
+ * associated bit mask.
+ *
+ * 3. If the range is positive, loop to avoid potential bias
+ * when the implicit nextLong() bound (2<sup>64</sup>) is not
+ * evenly divisible by the range. The loop rejects candidates
+ * computed from otherwise over-represented values. The
+ * expected number of iterations under an ideal generator
+ * varies from 1 to 2, depending on the bound. The loop itself
+ * takes an unlovable form. Because the first candidate is
+ * already available, we need a break-in-the-middle
+ * construction, which is concisely but cryptically performed
+ * within the while-condition of a body-less for loop.
+ *
+ * 4. Otherwise, the range cannot be represented as a positive
+ * long. The loop repeatedly generates unbounded longs until
+ * obtaining a candidate meeting constraints (with an expected
+ * number of iterations of less than two).
+ */
+
+ long r = mix64(nextSeed());
+ if (origin < bound) {
+ long n = bound - origin, m = n - 1;
+ if ((n & m) == 0L) // power of two
+ r = (r & m) + origin;
+ else if (n > 0L) { // reject over-represented candidates
+ for (long u = r >>> 1; // ensure nonnegative
+ u + m - (r = u % n) < 0L; // rejection check
+ u = mix64(nextSeed()) >>> 1) // retry
+ ;
+ r += origin;
+ }
+ else { // range not representable as long
+ while (r < origin || r >= bound)
+ r = mix64(nextSeed());
+ }
+ }
+ return r;
+ }
+
+ /**
+ * The form of nextInt used by IntStream Spliterators.
+ * Exactly the same as long version, except for types.
+ *
+ * @param origin the least value, unless greater than bound
+ * @param bound the upper bound (exclusive), must not equal origin
+ * @return a pseudorandom value
+ */
+ final int internalNextInt(int origin, int bound) {
+ int r = mix32(nextSeed());
+ if (origin < bound) {
+ int n = bound - origin, m = n - 1;
+ if ((n & m) == 0)
+ r = (r & m) + origin;
+ else if (n > 0) {
+ for (int u = r >>> 1;
+ u + m - (r = u % n) < 0;
+ u = mix32(nextSeed()) >>> 1)
+ ;
+ r += origin;
+ }
+ else {
+ while (r < origin || r >= bound)
+ r = mix32(nextSeed());
+ }
+ }
+ return r;
+ }
+
+ /**
+ * The form of nextDouble used by DoubleStream Spliterators.
+ *
+ * @param origin the least value, unless greater than bound
+ * @param bound the upper bound (exclusive), must not equal origin
+ * @return a pseudorandom value
+ */
+ final double internalNextDouble(double origin, double bound) {
+ double r = (nextLong() >>> 11) * DOUBLE_UNIT;
+ if (origin < bound) {
+ r = r * (bound - origin) + origin;
+ if (r >= bound) // correct for rounding
+ r = Double.longBitsToDouble(Double.doubleToLongBits(bound) - 1);
+ }
+ return r;
+ }
+
+ /* ---------------- public methods ---------------- */
+
+ /**
+ * Creates a new SplittableRandom instance using the specified
+ * initial seed. SplittableRandom instances created with the same
+ * seed in the same program generate identical sequences of values.
+ *
+ * @param seed the initial seed
+ */
+ public SplittableRandom(long seed) {
+ this(seed, INITIAL_GAMMA);
+ }
+
+ /**
+ * Creates a new SplittableRandom instance that is likely to
+ * generate sequences of values that are statistically independent
+ * of those of any other instances in the current program; and
+ * may, and typically does, vary across program invocations.
+ */
+ public SplittableRandom() { // emulate seeder.split()
+ this.gamma = nextGamma(this.seed = seeder.addAndGet(INITIAL_GAMMA));
+ }
+
+ /**
+ * Constructs and returns a new SplittableRandom instance that
+ * shares no mutable state with this instance. However, with very
+ * high probability, the set of values collectively generated by
+ * the two objects has the same statistical properties as if the
+ * same quantity of values were generated by a single thread using
+ * a single SplittableRandom object. Either or both of the two
+ * objects may be further split using the {@code split()} method,
+ * and the same expected statistical properties apply to the
+ * entire set of generators constructed by such recursive
+ * splitting.
+ *
+ * @return the new SplittableRandom instance
+ */
+ public SplittableRandom split() {
+ long s = nextSeed();
+ return new SplittableRandom(s, nextGamma(s));
+ }
+
+ /**
+ * Returns a pseudorandom {@code int} value.
+ *
+ * @return a pseudorandom {@code int} value
+ */
+ public int nextInt() {
+ return mix32(nextSeed());
+ }
+
+ /**
+ * Returns a pseudorandom {@code int} value between zero (inclusive)
+ * and the specified bound (exclusive).
+ *
+ * @param bound the upper bound (exclusive). Must be positive.
+ * @return a pseudorandom {@code int} value between zero
+ * (inclusive) and the bound (exclusive)
+ * @throws IllegalArgumentException if {@code bound} is not positive
+ */
+ public int nextInt(int bound) {
+ if (bound <= 0)
+ throw new IllegalArgumentException(BadBound);
+ // Specialize internalNextInt for origin 0
+ int r = mix32(nextSeed());
+ int m = bound - 1;
+ if ((bound & m) == 0) // power of two
+ r &= m;
+ else { // reject over-represented candidates
+ for (int u = r >>> 1;
+ u + m - (r = u % bound) < 0;
+ u = mix32(nextSeed()) >>> 1)
+ ;
+ }
+ return r;
+ }
+
+ /**
+ * Returns a pseudorandom {@code int} value between the specified
+ * origin (inclusive) and the specified bound (exclusive).
+ *
+ * @param origin the least value returned
+ * @param bound the upper bound (exclusive)
+ * @return a pseudorandom {@code int} value between the origin
+ * (inclusive) and the bound (exclusive)
+ * @throws IllegalArgumentException if {@code origin} is greater than
+ * or equal to {@code bound}
+ */
+ public int nextInt(int origin, int bound) {
+ if (origin >= bound)
+ throw new IllegalArgumentException(BadRange);
+ return internalNextInt(origin, bound);
+ }
+
+ /**
+ * Returns a pseudorandom {@code long} value.
+ *
+ * @return a pseudorandom {@code long} value
+ */
+ public long nextLong() {
+ return mix64(nextSeed());
+ }
+
+ /**
+ * Returns a pseudorandom {@code long} value between zero (inclusive)
+ * and the specified bound (exclusive).
+ *
+ * @param bound the upper bound (exclusive). Must be positive.
+ * @return a pseudorandom {@code long} value between zero
+ * (inclusive) and the bound (exclusive)
+ * @throws IllegalArgumentException if {@code bound} is not positive
+ */
+ public long nextLong(long bound) {
+ if (bound <= 0)
+ throw new IllegalArgumentException(BadBound);
+ // Specialize internalNextLong for origin 0
+ long r = mix64(nextSeed());
+ long m = bound - 1;
+ if ((bound & m) == 0L) // power of two
+ r &= m;
+ else { // reject over-represented candidates
+ for (long u = r >>> 1;
+ u + m - (r = u % bound) < 0L;
+ u = mix64(nextSeed()) >>> 1)
+ ;
+ }
+ return r;
+ }
+
+ /**
+ * Returns a pseudorandom {@code long} value between the specified
+ * origin (inclusive) and the specified bound (exclusive).
+ *
+ * @param origin the least value returned
+ * @param bound the upper bound (exclusive)
+ * @return a pseudorandom {@code long} value between the origin
+ * (inclusive) and the bound (exclusive)
+ * @throws IllegalArgumentException if {@code origin} is greater than
+ * or equal to {@code bound}
+ */
+ public long nextLong(long origin, long bound) {
+ if (origin >= bound)
+ throw new IllegalArgumentException(BadRange);
+ return internalNextLong(origin, bound);
+ }
+
+ /**
+ * Returns a pseudorandom {@code double} value between zero
+ * (inclusive) and one (exclusive).
+ *
+ * @return a pseudorandom {@code double} value between zero
+ * (inclusive) and one (exclusive)
+ */
+ public double nextDouble() {
+ return (mix64(nextSeed()) >>> 11) * DOUBLE_UNIT;
+ }
+
+ /**
+ * Returns a pseudorandom {@code double} value between 0.0
+ * (inclusive) and the specified bound (exclusive).
+ *
+ * @param bound the upper bound (exclusive). Must be positive.
+ * @return a pseudorandom {@code double} value between zero
+ * (inclusive) and the bound (exclusive)
+ * @throws IllegalArgumentException if {@code bound} is not positive
+ */
+ public double nextDouble(double bound) {
+ if (!(bound > 0.0))
+ throw new IllegalArgumentException(BadBound);
+ double result = (mix64(nextSeed()) >>> 11) * DOUBLE_UNIT * bound;
+ return (result < bound) ? result : // correct for rounding
+ Double.longBitsToDouble(Double.doubleToLongBits(bound) - 1);
+ }
+
+ /**
+ * Returns a pseudorandom {@code double} value between the specified
+ * origin (inclusive) and bound (exclusive).
+ *
+ * @param origin the least value returned
+ * @param bound the upper bound (exclusive)
+ * @return a pseudorandom {@code double} value between the origin
+ * (inclusive) and the bound (exclusive)
+ * @throws IllegalArgumentException if {@code origin} is greater than
+ * or equal to {@code bound}
+ */
+ public double nextDouble(double origin, double bound) {
+ if (!(origin < bound))
+ throw new IllegalArgumentException(BadRange);
+ return internalNextDouble(origin, bound);
+ }
+
+ /**
+ * Returns a pseudorandom {@code boolean} value.
+ *
+ * @return a pseudorandom {@code boolean} value
+ */
+ public boolean nextBoolean() {
+ return mix32(nextSeed()) < 0;
+ }
+
+ // stream methods, coded in a way intended to better isolate for
+ // maintenance purposes the small differences across forms.
+
+ /**
+ * Returns a stream producing the given {@code streamSize} number
+ * of pseudorandom {@code int} values from this generator and/or
+ * one split from it.
+ *
+ * @param streamSize the number of values to generate
+ * @return a stream of pseudorandom {@code int} values
+ * @throws IllegalArgumentException if {@code streamSize} is
+ * less than zero
+ */
+ public IntStream ints(long streamSize) {
+ if (streamSize < 0L)
+ throw new IllegalArgumentException(BadSize);
+ return StreamSupport.intStream
+ (new RandomIntsSpliterator
+ (this, 0L, streamSize, Integer.MAX_VALUE, 0),
+ false);
+ }
+
+ /**
+ * Returns an effectively unlimited stream of pseudorandom {@code int}
+ * values from this generator and/or one split from it.
+ *
+ * @implNote This method is implemented to be equivalent to {@code
+ * ints(Long.MAX_VALUE)}.
+ *
+ * @return a stream of pseudorandom {@code int} values
+ */
+ public IntStream ints() {
+ return StreamSupport.intStream
+ (new RandomIntsSpliterator
+ (this, 0L, Long.MAX_VALUE, Integer.MAX_VALUE, 0),
+ false);
+ }
+
+ /**
+ * Returns a stream producing the given {@code streamSize} number
+ * of pseudorandom {@code int} values from this generator and/or one split
+ * from it; each value conforms to the given origin (inclusive) and bound
+ * (exclusive).
+ *
+ * @param streamSize the number of values to generate
+ * @param randomNumberOrigin the origin (inclusive) of each random value
+ * @param randomNumberBound the bound (exclusive) of each random value
+ * @return a stream of pseudorandom {@code int} values,
+ * each with the given origin (inclusive) and bound (exclusive)
+ * @throws IllegalArgumentException if {@code streamSize} is
+ * less than zero, or {@code randomNumberOrigin}
+ * is greater than or equal to {@code randomNumberBound}
+ */
+ public IntStream ints(long streamSize, int randomNumberOrigin,
+ int randomNumberBound) {
+ if (streamSize < 0L)
+ throw new IllegalArgumentException(BadSize);
+ if (randomNumberOrigin >= randomNumberBound)
+ throw new IllegalArgumentException(BadRange);
+ return StreamSupport.intStream
+ (new RandomIntsSpliterator
+ (this, 0L, streamSize, randomNumberOrigin, randomNumberBound),
+ false);
+ }
+
+ /**
+ * Returns an effectively unlimited stream of pseudorandom {@code
+ * int} values from this generator and/or one split from it; each value
+ * conforms to the given origin (inclusive) and bound (exclusive).
+ *
+ * @implNote This method is implemented to be equivalent to {@code
+ * ints(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound)}.
+ *
+ * @param randomNumberOrigin the origin (inclusive) of each random value
+ * @param randomNumberBound the bound (exclusive) of each random value
+ * @return a stream of pseudorandom {@code int} values,
+ * each with the given origin (inclusive) and bound (exclusive)
+ * @throws IllegalArgumentException if {@code randomNumberOrigin}
+ * is greater than or equal to {@code randomNumberBound}
+ */
+ public IntStream ints(int randomNumberOrigin, int randomNumberBound) {
+ if (randomNumberOrigin >= randomNumberBound)
+ throw new IllegalArgumentException(BadRange);
+ return StreamSupport.intStream
+ (new RandomIntsSpliterator
+ (this, 0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound),
+ false);
+ }
+
+ /**
+ * Returns a stream producing the given {@code streamSize} number
+ * of pseudorandom {@code long} values from this generator and/or
+ * one split from it.
+ *
+ * @param streamSize the number of values to generate
+ * @return a stream of pseudorandom {@code long} values
+ * @throws IllegalArgumentException if {@code streamSize} is
+ * less than zero
+ */
+ public LongStream longs(long streamSize) {
+ if (streamSize < 0L)
+ throw new IllegalArgumentException(BadSize);
+ return StreamSupport.longStream
+ (new RandomLongsSpliterator
+ (this, 0L, streamSize, Long.MAX_VALUE, 0L),
+ false);
+ }
+
+ /**
+ * Returns an effectively unlimited stream of pseudorandom {@code
+ * long} values from this generator and/or one split from it.
+ *
+ * @implNote This method is implemented to be equivalent to {@code
+ * longs(Long.MAX_VALUE)}.
+ *
+ * @return a stream of pseudorandom {@code long} values
+ */
+ public LongStream longs() {
+ return StreamSupport.longStream
+ (new RandomLongsSpliterator
+ (this, 0L, Long.MAX_VALUE, Long.MAX_VALUE, 0L),
+ false);
+ }
+
+ /**
+ * Returns a stream producing the given {@code streamSize} number of
+ * pseudorandom {@code long} values from this generator and/or one split
+ * from it; each value conforms to the given origin (inclusive) and bound
+ * (exclusive).
+ *
+ * @param streamSize the number of values to generate
+ * @param randomNumberOrigin the origin (inclusive) of each random value
+ * @param randomNumberBound the bound (exclusive) of each random value
+ * @return a stream of pseudorandom {@code long} values,
+ * each with the given origin (inclusive) and bound (exclusive)
+ * @throws IllegalArgumentException if {@code streamSize} is
+ * less than zero, or {@code randomNumberOrigin}
+ * is greater than or equal to {@code randomNumberBound}
+ */
+ public LongStream longs(long streamSize, long randomNumberOrigin,
+ long randomNumberBound) {
+ if (streamSize < 0L)
+ throw new IllegalArgumentException(BadSize);
+ if (randomNumberOrigin >= randomNumberBound)
+ throw new IllegalArgumentException(BadRange);
+ return StreamSupport.longStream
+ (new RandomLongsSpliterator
+ (this, 0L, streamSize, randomNumberOrigin, randomNumberBound),
+ false);
+ }
+
+ /**
+ * Returns an effectively unlimited stream of pseudorandom {@code
+ * long} values from this generator and/or one split from it; each value
+ * conforms to the given origin (inclusive) and bound (exclusive).
+ *
+ * @implNote This method is implemented to be equivalent to {@code
+ * longs(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound)}.
+ *
+ * @param randomNumberOrigin the origin (inclusive) of each random value
+ * @param randomNumberBound the bound (exclusive) of each random value
+ * @return a stream of pseudorandom {@code long} values,
+ * each with the given origin (inclusive) and bound (exclusive)
+ * @throws IllegalArgumentException if {@code randomNumberOrigin}
+ * is greater than or equal to {@code randomNumberBound}
+ */
+ public LongStream longs(long randomNumberOrigin, long randomNumberBound) {
+ if (randomNumberOrigin >= randomNumberBound)
+ throw new IllegalArgumentException(BadRange);
+ return StreamSupport.longStream
+ (new RandomLongsSpliterator
+ (this, 0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound),
+ false);
+ }
+
+ /**
+ * Returns a stream producing the given {@code streamSize} number of
+ * pseudorandom {@code double} values from this generator and/or one split
+ * from it; each value is between zero (inclusive) and one (exclusive).
+ *
+ * @param streamSize the number of values to generate
+ * @return a stream of {@code double} values
+ * @throws IllegalArgumentException if {@code streamSize} is
+ * less than zero
+ */
+ public DoubleStream doubles(long streamSize) {
+ if (streamSize < 0L)
+ throw new IllegalArgumentException(BadSize);
+ return StreamSupport.doubleStream
+ (new RandomDoublesSpliterator
+ (this, 0L, streamSize, Double.MAX_VALUE, 0.0),
+ false);
+ }
+
+ /**
+ * Returns an effectively unlimited stream of pseudorandom {@code
+ * double} values from this generator and/or one split from it; each value
+ * is between zero (inclusive) and one (exclusive).
+ *
+ * @implNote This method is implemented to be equivalent to {@code
+ * doubles(Long.MAX_VALUE)}.
+ *
+ * @return a stream of pseudorandom {@code double} values
+ */
+ public DoubleStream doubles() {
+ return StreamSupport.doubleStream
+ (new RandomDoublesSpliterator
+ (this, 0L, Long.MAX_VALUE, Double.MAX_VALUE, 0.0),
+ false);
+ }
+
+ /**
+ * Returns a stream producing the given {@code streamSize} number of
+ * pseudorandom {@code double} values from this generator and/or one split
+ * from it; each value conforms to the given origin (inclusive) and bound
+ * (exclusive).
+ *
+ * @param streamSize the number of values to generate
+ * @param randomNumberOrigin the origin (inclusive) of each random value
+ * @param randomNumberBound the bound (exclusive) of each random value
+ * @return a stream of pseudorandom {@code double} values,
+ * each with the given origin (inclusive) and bound (exclusive)
+ * @throws IllegalArgumentException if {@code streamSize} is
+ * less than zero
+ * @throws IllegalArgumentException if {@code randomNumberOrigin}
+ * is greater than or equal to {@code randomNumberBound}
+ */
+ public DoubleStream doubles(long streamSize, double randomNumberOrigin,
+ double randomNumberBound) {
+ if (streamSize < 0L)
+ throw new IllegalArgumentException(BadSize);
+ if (!(randomNumberOrigin < randomNumberBound))
+ throw new IllegalArgumentException(BadRange);
+ return StreamSupport.doubleStream
+ (new RandomDoublesSpliterator
+ (this, 0L, streamSize, randomNumberOrigin, randomNumberBound),
+ false);
+ }
+
+ /**
+ * Returns an effectively unlimited stream of pseudorandom {@code
+ * double} values from this generator and/or one split from it; each value
+ * conforms to the given origin (inclusive) and bound (exclusive).
+ *
+ * @implNote This method is implemented to be equivalent to {@code
+ * doubles(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound)}.
+ *
+ * @param randomNumberOrigin the origin (inclusive) of each random value
+ * @param randomNumberBound the bound (exclusive) of each random value
+ * @return a stream of pseudorandom {@code double} values,
+ * each with the given origin (inclusive) and bound (exclusive)
+ * @throws IllegalArgumentException if {@code randomNumberOrigin}
+ * is greater than or equal to {@code randomNumberBound}
+ */
+ public DoubleStream doubles(double randomNumberOrigin, double randomNumberBound) {
+ if (!(randomNumberOrigin < randomNumberBound))
+ throw new IllegalArgumentException(BadRange);
+ return StreamSupport.doubleStream
+ (new RandomDoublesSpliterator
+ (this, 0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound),
+ false);
+ }
+
+ /**
+ * Spliterator for int streams. We multiplex the four int
+ * versions into one class by treating a bound less than origin as
+ * unbounded, and also by treating "infinite" as equivalent to
+ * Long.MAX_VALUE. For splits, it uses the standard divide-by-two
+ * approach. The long and double versions of this class are
+ * identical except for types.
+ */
+ static final class RandomIntsSpliterator implements Spliterator.OfInt {
+ final SplittableRandom rng;
+ long index;
+ final long fence;
+ final int origin;
+ final int bound;
+ RandomIntsSpliterator(SplittableRandom rng, long index, long fence,
+ int origin, int bound) {
+ this.rng = rng; this.index = index; this.fence = fence;
+ this.origin = origin; this.bound = bound;
+ }
+
+ public RandomIntsSpliterator trySplit() {
+ long i = index, m = (i + fence) >>> 1;
+ return (m <= i) ? null :
+ new RandomIntsSpliterator(rng.split(), i, index = m, origin, bound);
+ }
+
+ public long estimateSize() {
+ return fence - index;
+ }
+
+ public int characteristics() {
+ return (Spliterator.SIZED | Spliterator.SUBSIZED |
+ Spliterator.NONNULL | Spliterator.IMMUTABLE);
+ }
+
+ public boolean tryAdvance(IntConsumer consumer) {
+ if (consumer == null) throw new NullPointerException();
+ long i = index, f = fence;
+ if (i < f) {
+ consumer.accept(rng.internalNextInt(origin, bound));
+ index = i + 1;
+ return true;
+ }
+ return false;
+ }
+
+ public void forEachRemaining(IntConsumer consumer) {
+ if (consumer == null) throw new NullPointerException();
+ long i = index, f = fence;
+ if (i < f) {
+ index = f;
+ SplittableRandom r = rng;
+ int o = origin, b = bound;
+ do {
+ consumer.accept(r.internalNextInt(o, b));
+ } while (++i < f);
+ }
+ }
+ }
+
+ /**
+ * Spliterator for long streams.
+ */
+ static final class RandomLongsSpliterator implements Spliterator.OfLong {
+ final SplittableRandom rng;
+ long index;
+ final long fence;
+ final long origin;
+ final long bound;
+ RandomLongsSpliterator(SplittableRandom rng, long index, long fence,
+ long origin, long bound) {
+ this.rng = rng; this.index = index; this.fence = fence;
+ this.origin = origin; this.bound = bound;
+ }
+
+ public RandomLongsSpliterator trySplit() {
+ long i = index, m = (i + fence) >>> 1;
+ return (m <= i) ? null :
+ new RandomLongsSpliterator(rng.split(), i, index = m, origin, bound);
+ }
+
+ public long estimateSize() {
+ return fence - index;
+ }
+
+ public int characteristics() {
+ return (Spliterator.SIZED | Spliterator.SUBSIZED |
+ Spliterator.NONNULL | Spliterator.IMMUTABLE);
+ }
+
+ public boolean tryAdvance(LongConsumer consumer) {
+ if (consumer == null) throw new NullPointerException();
+ long i = index, f = fence;
+ if (i < f) {
+ consumer.accept(rng.internalNextLong(origin, bound));
+ index = i + 1;
+ return true;
+ }
+ return false;
+ }
+
+ public void forEachRemaining(LongConsumer consumer) {
+ if (consumer == null) throw new NullPointerException();
+ long i = index, f = fence;
+ if (i < f) {
+ index = f;
+ SplittableRandom r = rng;
+ long o = origin, b = bound;
+ do {
+ consumer.accept(r.internalNextLong(o, b));
+ } while (++i < f);
+ }
+ }
+
+ }
+
+ /**
+ * Spliterator for double streams.
+ */
+ static final class RandomDoublesSpliterator implements Spliterator.OfDouble {
+ final SplittableRandom rng;
+ long index;
+ final long fence;
+ final double origin;
+ final double bound;
+ RandomDoublesSpliterator(SplittableRandom rng, long index, long fence,
+ double origin, double bound) {
+ this.rng = rng; this.index = index; this.fence = fence;
+ this.origin = origin; this.bound = bound;
+ }
+
+ public RandomDoublesSpliterator trySplit() {
+ long i = index, m = (i + fence) >>> 1;
+ return (m <= i) ? null :
+ new RandomDoublesSpliterator(rng.split(), i, index = m, origin, bound);
+ }
+
+ public long estimateSize() {
+ return fence - index;
+ }
+
+ public int characteristics() {
+ return (Spliterator.SIZED | Spliterator.SUBSIZED |
+ Spliterator.NONNULL | Spliterator.IMMUTABLE);
+ }
+
+ public boolean tryAdvance(DoubleConsumer consumer) {
+ if (consumer == null) throw new NullPointerException();
+ long i = index, f = fence;
+ if (i < f) {
+ consumer.accept(rng.internalNextDouble(origin, bound));
+ index = i + 1;
+ return true;
+ }
+ return false;
+ }
+
+ public void forEachRemaining(DoubleConsumer consumer) {
+ if (consumer == null) throw new NullPointerException();
+ long i = index, f = fence;
+ if (i < f) {
+ index = f;
+ SplittableRandom r = rng;
+ double o = origin, b = bound;
+ do {
+ consumer.accept(r.internalNextDouble(o, b));
+ } while (++i < f);
+ }
+ }
+ }
+
+}