/*
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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/*
 *
 *
 *
 *
 *
 * Written by Doug Lea with assistance from members of JCP JSR-166
 * Expert Group and released to the public domain, as explained at
 * http://creativecommons.org/publicdomain/zero/1.0/
 */

package java.util.concurrent;

import java.io.ObjectStreamField;
import java.security.AccessControlContext;
import java.util.Random;
import java.util.Spliterator;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicLong;
import java.util.function.DoubleConsumer;
import java.util.function.IntConsumer;
import java.util.function.LongConsumer;
import java.util.stream.DoubleStream;
import java.util.stream.IntStream;
import java.util.stream.LongStream;
import java.util.stream.StreamSupport;
import jdk.internal.misc.Unsafe;
import jdk.internal.misc.VM;

/**
 * A random number generator isolated to the current thread. Like the
 * global {@link java.util.Random} generator used by the {@link
 * java.lang.Math} class, a {@code ThreadLocalRandom} is initialized
 * with an internally generated seed that may not otherwise be
 * modified. When applicable, use of {@code ThreadLocalRandom} rather
 * than shared {@code Random} objects in concurrent programs will
 * typically encounter much less overhead and contention. Use of
 * {@code ThreadLocalRandom} is particularly appropriate when multiple
 * tasks (for example, each a {@link ForkJoinTask}) use random numbers
 * in parallel in thread pools.
 *
 * <p>Usages of this class should typically be of the form:
 * {@code ThreadLocalRandom.current().nextX(...)} (where
 * {@code X} is {@code Int}, {@code Long}, etc).
 * When all usages are of this form, it is never possible to
 * accidentally share a {@code ThreadLocalRandom} across multiple threads.
 *
 * <p>This class also provides additional commonly used bounded random
 * generation methods.
 *
 * <p>Instances of {@code ThreadLocalRandom} 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 1.7
 * @author Doug Lea
 */
public class ThreadLocalRandom extends Random {
 /*
 * This class implements the java.util.Random API (and subclasses
 * Random) using a single static instance that accesses random
 * number state held in class Thread (primarily, field
 * threadLocalRandomSeed). In doing so, it also provides a home
 * for managing package-private utilities that rely on exactly the
 * same state as needed to maintain the ThreadLocalRandom
 * instances. We leverage the need for an initialization flag
 * field to also use it as a "probe" -- a self-adjusting thread
 * hash used for contention avoidance, as well as a secondary
 * simpler (xorShift) random seed that is conservatively used to
 * avoid otherwise surprising users by hijacking the
 * ThreadLocalRandom sequence. The dual use is a marriage of
 * convenience, but is a simple and efficient way of reducing
 * application-level overhead and footprint of most concurrent
 * programs. Even more opportunistically, we also define here
 * other package-private utilities that access Thread class
 * fields.
 *
 * Even though this class subclasses java.util.Random, it uses the
 * same basic algorithm as java.util.SplittableRandom. (See its
 * internal documentation for explanations, which are not repeated
 * here.) Because ThreadLocalRandoms are not splittable
 * though, we use only a single 64bit gamma.
 *
 * Because this class is in a different package than class Thread,
 * field access methods use Unsafe to bypass access control rules.
 * To conform to the requirements of the Random superclass
 * constructor, the common static ThreadLocalRandom maintains an
 * "initialized" field for the sake of rejecting user calls to
 * setSeed while still allowing a call from constructor. Note
 * that serialization is completely unnecessary because there is
 * only a static singleton. But we generate a serial form
 * containing "rnd" and "initialized" fields to ensure
 * compatibility across versions.
 *
 * Implementations of non-core methods are mostly the same as in
 * SplittableRandom, that were in part derived from a previous
 * version of this class.
 *
 * The nextLocalGaussian ThreadLocal supports the very rarely used
 * nextGaussian method by providing a holder for the second of a
 * pair of them. As is true for the base class version of this
 * method, this time/space tradeoff is probably never worthwhile,
 * but we provide identical statistical properties.
 */

 private static long mix64(long z) {
 z = (z ^ (z >>> 33)) * 0xff51afd7ed558ccdL;
 z = (z ^ (z >>> 33)) * 0xc4ceb9fe1a85ec53L;
 return z ^ (z >>> 33);
 }

 private static int mix32(long z) {
 z = (z ^ (z >>> 33)) * 0xff51afd7ed558ccdL;
 return (int)(((z ^ (z >>> 33)) * 0xc4ceb9fe1a85ec53L) >>> 32);
 }

 /**
 * Field used only during singleton initialization.
 * True when constructor completes.
 */
 boolean initialized;

 /** Constructor used only for static singleton */
 private ThreadLocalRandom() {
 initialized = true; // false during super() call
 }

 /**
 * Initialize Thread fields for the current thread. Called only
 * when Thread.threadLocalRandomProbe is zero, indicating that a
 * thread local seed value needs to be generated. Note that even
 * though the initialization is purely thread-local, we need to
 * rely on (static) atomic generators to initialize the values.
 */
 static final void localInit() {
 int p = probeGenerator.addAndGet(PROBE_INCREMENT);
 int probe = (p == 0) ? 1 : p; // skip 0
 long seed = mix64(seeder.getAndAdd(SEEDER_INCREMENT));
 Thread t = Thread.currentThread();
 U.putLong(t, SEED, seed);
 U.putInt(t, PROBE, probe);
 }

 /**
 * Returns the current thread's {@code ThreadLocalRandom}.
 *
 * @return the current thread's {@code ThreadLocalRandom}
 */
 public static ThreadLocalRandom current() {
 if (U.getInt(Thread.currentThread(), PROBE) == 0)
 localInit();
 return instance;
 }

 /**
 * Throws {@code UnsupportedOperationException}. Setting seeds in
 * this generator is not supported.
 *
 * @throws UnsupportedOperationException always
 */
 public void setSeed(long seed) {
 // only allow call from super() constructor
 if (initialized)
 throw new UnsupportedOperationException();
 }

 final long nextSeed() {
 Thread t; long r; // read and update per-thread seed
 U.putLong(t = Thread.currentThread(), SEED,
 r = U.getLong(t, SEED) + GAMMA);
 return r;
 }

 /**
 * Generates a pseudorandom number with the indicated number of
 * low-order bits. Because this class has no subclasses, this
 * method cannot be invoked or overridden.
 *
 * @param bits random bits
 * @return the next pseudorandom value from this random number
 * generator's sequence
 */
 protected int next(int bits) {
 return nextInt() >>> (32 - bits);
 }

 /**
 * 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) {
 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;
 }

 /**
 * 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(BAD_BOUND);
 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(BAD_RANGE);
 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(BAD_BOUND);
 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(BAD_RANGE);
 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(BAD_BOUND);
 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(BAD_RANGE);
 return internalNextDouble(origin, bound);
 }

 /**
 * Returns a pseudorandom {@code boolean} value.
 *
 * @return a pseudorandom {@code boolean} value
 */
 public boolean nextBoolean() {
 return mix32(nextSeed()) < 0;
 }

 /**
 * Returns a pseudorandom {@code float} value between zero
 * (inclusive) and one (exclusive).
 *
 * @return a pseudorandom {@code float} value between zero
 * (inclusive) and one (exclusive)
 */
 public float nextFloat() {
 return (mix32(nextSeed()) >>> 8) * FLOAT_UNIT;
 }

 public double nextGaussian() {
 // Use nextLocalGaussian instead of nextGaussian field
 Double d = nextLocalGaussian.get();
 if (d != null) {
 nextLocalGaussian.set(null);
 return d.doubleValue();
 }
 double v1, v2, s;
 do {
 v1 = 2 * nextDouble() - 1; // between -1 and 1
 v2 = 2 * nextDouble() - 1; // between -1 and 1
 s = v1 * v1 + v2 * v2;
 } while (s >= 1 || s == 0);
 double multiplier = StrictMath.sqrt(-2 * StrictMath.log(s)/s);
 nextLocalGaussian.set(Double.valueOf(v2 * multiplier));
 return v1 * multiplier;
 }

 // 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.
 *
 * @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
 * @since 1.8
 */
 public IntStream ints(long streamSize) {
 if (streamSize < 0L)
 throw new IllegalArgumentException(BAD_SIZE);
 return StreamSupport.intStream
 (new RandomIntsSpliterator
 (0L, streamSize, Integer.MAX_VALUE, 0),
 false);
 }

 /**
 * Returns an effectively unlimited stream of pseudorandom {@code int}
 * values.
 *
 * @implNote This method is implemented to be equivalent to {@code
 * ints(Long.MAX_VALUE)}.
 *
 * @return a stream of pseudorandom {@code int} values
 * @since 1.8
 */
 public IntStream ints() {
 return StreamSupport.intStream
 (new RandomIntsSpliterator
 (0L, Long.MAX_VALUE, Integer.MAX_VALUE, 0),
 false);
 }

 /**
 * Returns a stream producing the given {@code streamSize} number
 * of pseudorandom {@code int} values, each conforming 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}
 * @since 1.8
 */
 public IntStream ints(long streamSize, int randomNumberOrigin,
 int randomNumberBound) {
 if (streamSize < 0L)
 throw new IllegalArgumentException(BAD_SIZE);
 if (randomNumberOrigin >= randomNumberBound)
 throw new IllegalArgumentException(BAD_RANGE);
 return StreamSupport.intStream
 (new RandomIntsSpliterator
 (0L, streamSize, randomNumberOrigin, randomNumberBound),
 false);
 }

 /**
 * Returns an effectively unlimited stream of pseudorandom {@code
 * int} values, each conforming 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}
 * @since 1.8
 */
 public IntStream ints(int randomNumberOrigin, int randomNumberBound) {
 if (randomNumberOrigin >= randomNumberBound)
 throw new IllegalArgumentException(BAD_RANGE);
 return StreamSupport.intStream
 (new RandomIntsSpliterator
 (0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound),
 false);
 }

 /**
 * Returns a stream producing the given {@code streamSize} number of
 * pseudorandom {@code long} values.
 *
 * @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
 * @since 1.8
 */
 public LongStream longs(long streamSize) {
 if (streamSize < 0L)
 throw new IllegalArgumentException(BAD_SIZE);
 return StreamSupport.longStream
 (new RandomLongsSpliterator
 (0L, streamSize, Long.MAX_VALUE, 0L),
 false);
 }

 /**
 * Returns an effectively unlimited stream of pseudorandom {@code long}
 * values.
 *
 * @implNote This method is implemented to be equivalent to {@code
 * longs(Long.MAX_VALUE)}.
 *
 * @return a stream of pseudorandom {@code long} values
 * @since 1.8
 */
 public LongStream longs() {
 return StreamSupport.longStream
 (new RandomLongsSpliterator
 (0L, Long.MAX_VALUE, Long.MAX_VALUE, 0L),
 false);
 }

 /**
 * Returns a stream producing the given {@code streamSize} number of
 * pseudorandom {@code long}, each conforming 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}
 * @since 1.8
 */
 public LongStream longs(long streamSize, long randomNumberOrigin,
 long randomNumberBound) {
 if (streamSize < 0L)
 throw new IllegalArgumentException(BAD_SIZE);
 if (randomNumberOrigin >= randomNumberBound)
 throw new IllegalArgumentException(BAD_RANGE);
 return StreamSupport.longStream
 (new RandomLongsSpliterator
 (0L, streamSize, randomNumberOrigin, randomNumberBound),
 false);
 }

 /**
 * Returns an effectively unlimited stream of pseudorandom {@code
 * long} values, each conforming 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}
 * @since 1.8
 */
 public LongStream longs(long randomNumberOrigin, long randomNumberBound) {
 if (randomNumberOrigin >= randomNumberBound)
 throw new IllegalArgumentException(BAD_RANGE);
 return StreamSupport.longStream
 (new RandomLongsSpliterator
 (0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound),
 false);
 }

 /**
 * Returns a stream producing the given {@code streamSize} number of
 * pseudorandom {@code double} values, each 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
 * @since 1.8
 */
 public DoubleStream doubles(long streamSize) {
 if (streamSize < 0L)
 throw new IllegalArgumentException(BAD_SIZE);
 return StreamSupport.doubleStream
 (new RandomDoublesSpliterator
 (0L, streamSize, Double.MAX_VALUE, 0.0),
 false);
 }

 /**
 * Returns an effectively unlimited stream of pseudorandom {@code
 * double} values, each 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
 * @since 1.8
 */
 public DoubleStream doubles() {
 return StreamSupport.doubleStream
 (new RandomDoublesSpliterator
 (0L, Long.MAX_VALUE, Double.MAX_VALUE, 0.0),
 false);
 }

 /**
 * Returns a stream producing the given {@code streamSize} number of
 * pseudorandom {@code double} values, each conforming 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, or {@code randomNumberOrigin}
 * is greater than or equal to {@code randomNumberBound}
 * @since 1.8
 */
 public DoubleStream doubles(long streamSize, double randomNumberOrigin,
 double randomNumberBound) {
 if (streamSize < 0L)
 throw new IllegalArgumentException(BAD_SIZE);
 if (!(randomNumberOrigin < randomNumberBound))
 throw new IllegalArgumentException(BAD_RANGE);
 return StreamSupport.doubleStream
 (new RandomDoublesSpliterator
 (0L, streamSize, randomNumberOrigin, randomNumberBound),
 false);
 }

 /**
 * Returns an effectively unlimited stream of pseudorandom {@code
 * double} values, each conforming 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}
 * @since 1.8
 */
 public DoubleStream doubles(double randomNumberOrigin, double randomNumberBound) {
 if (!(randomNumberOrigin < randomNumberBound))
 throw new IllegalArgumentException(BAD_RANGE);
 return StreamSupport.doubleStream
 (new RandomDoublesSpliterator
 (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.
 */
 private static final class RandomIntsSpliterator
 implements Spliterator.OfInt {
 long index;
 final long fence;
 final int origin;
 final int bound;
 RandomIntsSpliterator(long index, long fence,
 int origin, int bound) {
 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(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(ThreadLocalRandom.current().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;
 int o = origin, b = bound;
 ThreadLocalRandom rng = ThreadLocalRandom.current();
 do {
 consumer.accept(rng.internalNextInt(o, b));
 } while (++i < f);
 }
 }
 }

 /**
 * Spliterator for long streams.
 */
 private static final class RandomLongsSpliterator
 implements Spliterator.OfLong {
 long index;
 final long fence;
 final long origin;
 final long bound;
 RandomLongsSpliterator(long index, long fence,
 long origin, long bound) {
 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(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(ThreadLocalRandom.current().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;
 long o = origin, b = bound;
 ThreadLocalRandom rng = ThreadLocalRandom.current();
 do {
 consumer.accept(rng.internalNextLong(o, b));
 } while (++i < f);
 }
 }

 }

 /**
 * Spliterator for double streams.
 */
 private static final class RandomDoublesSpliterator
 implements Spliterator.OfDouble {
 long index;
 final long fence;
 final double origin;
 final double bound;
 RandomDoublesSpliterator(long index, long fence,
 double origin, double bound) {
 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(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(ThreadLocalRandom.current().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;
 double o = origin, b = bound;
 ThreadLocalRandom rng = ThreadLocalRandom.current();
 do {
 consumer.accept(rng.internalNextDouble(o, b));
 } while (++i < f);
 }
 }
 }


 // Within-package utilities

 /*
 * Descriptions of the usages of the methods below can be found in
 * the classes that use them. Briefly, a thread's "probe" value is
 * a non-zero hash code that (probably) does not collide with
 * other existing threads with respect to any power of two
 * collision space. When it does collide, it is pseudo-randomly
 * adjusted (using a Marsaglia XorShift). The nextSecondarySeed
 * method is used in the same contexts as ThreadLocalRandom, but
 * only for transient usages such as random adaptive spin/block
 * sequences for which a cheap RNG suffices and for which it could
 * in principle disrupt user-visible statistical properties of the
 * main ThreadLocalRandom if we were to use it.
 *
 * Note: Because of package-protection issues, versions of some
 * these methods also appear in some subpackage classes.
 */

 /**
 * Returns the probe value for the current thread without forcing
 * initialization. Note that invoking ThreadLocalRandom.current()
 * can be used to force initialization on zero return.
 */
 static final int getProbe() {
 return U.getInt(Thread.currentThread(), PROBE);
 }

 /**
 * Pseudo-randomly advances and records the given probe value for the
 * given thread.
 */
 static final int advanceProbe(int probe) {
 probe ^= probe << 13; // xorshift
 probe ^= probe >>> 17;
 probe ^= probe << 5;
 U.putInt(Thread.currentThread(), PROBE, probe);
 return probe;
 }

 /**
 * Returns the pseudo-randomly initialized or updated secondary seed.
 */
 static final int nextSecondarySeed() {
 int r;
 Thread t = Thread.currentThread();
 if ((r = U.getInt(t, SECONDARY)) != 0) {
 r ^= r << 13; // xorshift
 r ^= r >>> 17;
 r ^= r << 5;
 }
 else if ((r = mix32(seeder.getAndAdd(SEEDER_INCREMENT))) == 0)
 r = 1; // avoid zero
 U.putInt(t, SECONDARY, r);
 return r;
 }

 // Support for other package-private ThreadLocal access

 /**
 * Erases ThreadLocals by nulling out Thread maps.
 */
 static final void eraseThreadLocals(Thread thread) {
 U.putObject(thread, THREADLOCALS, null);
 U.putObject(thread, INHERITABLETHREADLOCALS, null);
 }

 static final void setInheritedAccessControlContext(Thread thread,
 AccessControlContext acc) {
 U.putObjectRelease(thread, INHERITEDACCESSCONTROLCONTEXT, acc);
 }

 // Serialization support

 private static final long serialVersionUID = -5851777807851030925L;

 /**
 * @serialField rnd long
 * seed for random computations
 * @serialField initialized boolean
 * always true
 */
 private static final ObjectStreamField[] serialPersistentFields = {
 new ObjectStreamField("rnd", long.class),
 new ObjectStreamField("initialized", boolean.class),
 };

 /**
 * Saves the {@code ThreadLocalRandom} to a stream (that is, serializes it).
 * @param s the stream
 * @throws java.io.IOException if an I/O error occurs
 */
 private void writeObject(java.io.ObjectOutputStream s)
 throws java.io.IOException {

 java.io.ObjectOutputStream.PutField fields = s.putFields();
 fields.put("rnd", U.getLong(Thread.currentThread(), SEED));
 fields.put("initialized", true);
 s.writeFields();
 }

 /**
 * Returns the {@link #current() current} thread's {@code ThreadLocalRandom}.
 * @return the {@link #current() current} thread's {@code ThreadLocalRandom}
 */
 private Object readResolve() {
 return current();
 }

 // Static initialization

 /**
 * The seed increment.
 */
 private static final long GAMMA = 0x9e3779b97f4a7c15L;

 /**
 * The increment for generating probe values.
 */
 private static final int PROBE_INCREMENT = 0x9e3779b9;

 /**
 * The increment of seeder per new instance.
 */
 private static final long SEEDER_INCREMENT = 0xbb67ae8584caa73bL;

 /**
 * 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 = 0x1.0p-53; // 1.0 / (1L << 53)
 private static final float FLOAT_UNIT = 0x1.0p-24f; // 1.0f / (1 << 24)

 // IllegalArgumentException messages
 static final String BAD_BOUND = "bound must be positive";
 static final String BAD_RANGE = "bound must be greater than origin";
 static final String BAD_SIZE = "size must be non-negative";

 // Unsafe mechanics
 private static final Unsafe U = Unsafe.getUnsafe();
 private static final long SEED = U.objectFieldOffset
 (Thread.class, "threadLocalRandomSeed");
 private static final long PROBE = U.objectFieldOffset
 (Thread.class, "threadLocalRandomProbe");
 private static final long SECONDARY = U.objectFieldOffset
 (Thread.class, "threadLocalRandomSecondarySeed");
 private static final long THREADLOCALS = U.objectFieldOffset
 (Thread.class, "threadLocals");
 private static final long INHERITABLETHREADLOCALS = U.objectFieldOffset
 (Thread.class, "inheritableThreadLocals");
 private static final long INHERITEDACCESSCONTROLCONTEXT = U.objectFieldOffset
 (Thread.class, "inheritedAccessControlContext");

 /** Rarely-used holder for the second of a pair of Gaussians */
 private static final ThreadLocal<Double> nextLocalGaussian =
 new ThreadLocal<>();

 /** Generates per-thread initialization/probe field */
 private static final AtomicInteger probeGenerator = new AtomicInteger();

 /** The common ThreadLocalRandom */
 static final ThreadLocalRandom instance = new ThreadLocalRandom();

 /**
 * The next seed for default constructors.
 */
 private static final AtomicLong seeder
 = new AtomicLong(mix64(System.currentTimeMillis()) ^
 mix64(System.nanoTime()));

 // at end of <clinit> to survive static initialization circularity
 static {
 String sec = VM.getSavedProperty("java.util.secureRandomSeed");
 if (Boolean.parseBoolean(sec)) {
 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);
 seeder.set(s);
 }
 }
}