--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/newrandom/AbstractArbitrarilyJumpableRng.java Thu May 23 16:45:56 2019 -0400
@@ -0,0 +1,543 @@
+/*
+ * Copyright (c) 2016, 2019, Oracle and/or its affiliates. All rights reserved.
+ * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ *
+ */
+
+// package java.util;
+
+import java.util.Spliterator;
+import java.util.function.Consumer;
+import java.util.function.IntConsumer;
+import java.util.function.LongConsumer;
+import java.util.function.DoubleConsumer;
+import java.util.stream.StreamSupport;
+import java.util.stream.Stream;
+
+/**
+ * This class provides much of the implementation of the
+ * {@code ArbitrarilyJumpableRng} interface, to minimize the effort
+ * required to implement that interface.
+ *
+ * To implement a pseudorandom number generator, the programmer needs
+ * only to extend this class and provide implementations for the
+ * methods {@code nextInt()}, {@code nextLong()}, {@code copy()},
+ * {@code jump(distance)}, {@code jumpPowerOfTwo(distance)},
+ * {@code defaultJumpDistance()}, and {@code defaultLeapDistance()}.
+ *
+ * (If the pseudorandom number generator also has the ability to split,
+ * then the programmer may wish to consider instead extending
+ * {@code AbstractSplittableArbitrarilyJumpableRng}.)
+ *
+ * The programmer should generally provide at least three constructors:
+ * one that takes no arguments, one that accepts a {@code long}
+ * seed value, and one that accepts an array of seed {@code byte} values.
+ * This class provides a public {@code initialSeed()} method that may
+ * be useful in initializing some static state from which to derive
+ * defaults seeds for use by the no-argument constructor.
+ *
+ * For the stream methods (such as {@code ints()} and {@code splits()}),
+ * this class provides {@code Spliterator}-based implementations that
+ * allow parallel execution when appropriate. In this respect
+ * {@code ArbitrarilyJumpableRng} differs from {@code JumpableRng},
+ * which provides very simple implementations that produce
+ * sequential streams only.
+ *
+ * <p>An implementation of the {@code AbstractArbitrarilyJumpableRng} class
+ * must provide concrete definitions for the methods {@code nextInt()},
+ * {@code nextLong}, {@code period()}, {@code copy()}, {@code jump(double)},
+ * {@code defaultJumpDistance()}, and {@code defaultLeapDistance()}.
+ * Default implementations are provided for all other methods.
+ *
+ * The documentation for each non-abstract method in this class
+ * describes its implementation in detail. Each of these methods may
+ * be overridden if the pseudorandom number generator being
+ * implemented admits a more efficient implementation.
+ *
+ * @author Guy Steele
+ * @since 1.9
+ */
+public abstract class AbstractArbitrarilyJumpableRng
+ extends AbstractSpliteratorRng implements ArbitrarilyJumpableRng {
+
+ /*
+ * Implementation Overview.
+ *
+ * This class provides most of the "user API" methods needed to satisfy
+ * the interface java.util.ArbitrarilyJumpableRng. Most of these methods
+ * are in turn inherited from AbstractRng and the non-public class
+ * AbstractSpliteratorRng; this file implements four versions of the
+ * jumps method and defines the spliterators necessary to support them.
+ *
+ * File organization: First the non-public methods needed by the class
+ * AbstractSpliteratorRng, then the main public methods, followed by some
+ * custom spliterator classes needed for stream methods.
+ */
+
+ // IllegalArgumentException messages
+ static final String BadLogDistance = "logDistance must be non-negative";
+
+ // Methods required by class AbstractSpliteratorRng
+ Spliterator.OfInt makeIntsSpliterator(long index, long fence, int origin, int bound) {
+ return new RandomIntsSpliterator(this, index, fence, origin, bound);
+ }
+ Spliterator.OfLong makeLongsSpliterator(long index, long fence, long origin, long bound) {
+ return new RandomLongsSpliterator(this, index, fence, origin, bound);
+ }
+ Spliterator.OfDouble makeDoublesSpliterator(long index, long fence, double origin, double bound) {
+ return new RandomDoublesSpliterator(this, index, fence, origin, bound);
+ }
+
+ // Similar methods used by this class
+ Spliterator<Rng> makeJumpsSpliterator(long index, long fence, double distance) {
+ return new RandomJumpsSpliterator(this, index, fence, distance);
+ }
+ Spliterator<JumpableRng> makeLeapsSpliterator(long index, long fence, double distance) {
+ return new RandomLeapsSpliterator(this, index, fence, distance);
+ }
+ Spliterator<ArbitrarilyJumpableRng> makeArbitraryJumpsSpliterator(long index, long fence, double distance) {
+ return new RandomArbitraryJumpsSpliterator(this, index, fence, distance);
+ }
+
+ /* ---------------- public methods ---------------- */
+
+ /**
+ * Returns a new generator whose internal state is an exact copy
+ * of this generator (therefore their future behavior should be
+ * identical if subjected to the same series of operations).
+ *
+ * @return a new object that is a copy of this generator
+ */
+ public abstract AbstractArbitrarilyJumpableRng copy();
+
+ // Stream methods for jumping
+
+ /**
+ * Returns an effectively unlimited stream of new pseudorandom
+ * number generators, each of which implements the {@code Rng}
+ * interface, produced by jumping copies of this generator
+ * by different integer multiples of the default jump distance.
+ *
+ * @implNote This method is implemented to be equivalent to
+ * {@code jumps(Long.MAX_VALUE)}.
+ *
+ * @return a stream of objects that implement the {@code Rng} interface
+ */
+ public Stream<Rng> jumps() {
+ return StreamSupport.stream
+ (makeJumpsSpliterator(0L, Long.MAX_VALUE, defaultJumpDistance()),
+ false);
+ }
+
+ /**
+ * Returns a stream producing the given {@code streamSize} number of
+ * new pseudorandom number generators, each of which implements the
+ * {@code Rng} interface, produced by jumping copies of this generator
+ * by different integer multiples of the default jump distance.
+ *
+ * @param streamSize the number of generators to generate
+ * @return a stream of objects that implement the {@code Rng} interface
+ * @throws IllegalArgumentException if {@code streamSize} is
+ * less than zero
+ */
+ public Stream<Rng> jumps(long streamSize) {
+ return StreamSupport.stream
+ (makeJumpsSpliterator(0L, streamSize, defaultJumpDistance()),
+ false);
+ }
+
+ /**
+ * Returns an effectively unlimited stream of new pseudorandom
+ * number generators, each of which implements the {@code Rng}
+ * interface, produced by jumping copies of this generator
+ * by different integer multiples of the specified jump distance.
+ *
+ * @implNote This method is implemented to be equivalent to
+ * {@code jumps(Long.MAX_VALUE)}.
+ *
+ * @param distance a distance to jump forward within the state cycle
+ * @return a stream of objects that implement the {@code Rng} interface
+ */
+ public Stream<ArbitrarilyJumpableRng> jumps(double distance) {
+ return StreamSupport.stream
+ (makeArbitraryJumpsSpliterator(0L, Long.MAX_VALUE, distance),
+ false);
+ }
+
+ /**
+ * Returns a stream producing the given {@code streamSize} number of
+ * new pseudorandom number generators, each of which implements the
+ * {@code Rng} interface, produced by jumping copies of this generator
+ * by different integer multiples of the specified jump distance.
+ *
+ * @param streamSize the number of generators to generate
+ * @param distance a distance to jump forward within the state cycle
+ * @return a stream of objects that implement the {@code Rng} interface
+ * @throws IllegalArgumentException if {@code streamSize} is
+ * less than zero
+ */
+ public Stream<ArbitrarilyJumpableRng> jumps(long streamSize, double distance) {
+ RngSupport.checkStreamSize(streamSize);
+ return StreamSupport.stream
+ (makeArbitraryJumpsSpliterator(0L, streamSize, distance),
+ false);
+ }
+
+ /**
+ * Alter the state of this pseudorandom number generator so as to
+ * jump forward a very large, fixed distance (typically 2<sup>128</sup>
+ * or more) within its state cycle. The distance used is that
+ * returned by method {@code defaultLeapDistance()}.
+ */
+ public void leap() { jump(defaultLeapDistance()); }
+
+ // Stream methods for leaping
+
+ /**
+ * Returns an effectively unlimited stream of new pseudorandom
+ * number generators, each of which implements the {@code Rng}
+ * interface, produced by jumping copies of this generator
+ * by different integer multiples of the default leap distance.
+ *
+ * @implNote This method is implemented to be equivalent to
+ * {@code leaps(Long.MAX_VALUE)}.
+ *
+ * @return a stream of objects that implement the {@code Rng} interface
+ */
+ public Stream<JumpableRng> leaps() {
+ return StreamSupport.stream
+ (makeLeapsSpliterator(0L, Long.MAX_VALUE, defaultLeapDistance()),
+ false);
+ }
+
+ /**
+ * Returns a stream producing the given {@code streamSize} number of
+ * new pseudorandom number generators, each of which implements the
+ * {@code Rng} interface, produced by jumping copies of this generator
+ * by different integer multiples of the default leap distance.
+ *
+ * @param streamSize the number of generators to generate
+ * @return a stream of objects that implement the {@code Rng} interface
+ * @throws IllegalArgumentException if {@code streamSize} is
+ * less than zero
+ */
+ public Stream<JumpableRng> leaps(long streamSize) {
+ return StreamSupport.stream
+ (makeLeapsSpliterator(0L, streamSize, defaultLeapDistance()),
+ 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, we choose to override the method
+ * {@code trySplit()} to try to optimize execution speed: instead of
+ * dividing a range in half, it breaks off the largest possible chunk
+ * whose size is a power of two such that the remaining chunk is not
+ * empty. In this way, the necessary jump distances will tend to be
+ * powers of two. The long and double versions of this class are
+ * identical except for types.
+ */
+ static class RandomIntsSpliterator extends RngSupport.RandomSpliterator implements Spliterator.OfInt {
+ final ArbitrarilyJumpableRng generatingRng;
+ final int origin;
+ final int bound;
+
+ RandomIntsSpliterator(ArbitrarilyJumpableRng generatingRng, long index, long fence, int origin, int bound) {
+ super(index, fence);
+ this.origin = origin; this.bound = bound;
+ this.generatingRng = generatingRng;
+ }
+
+ public Spliterator.OfInt trySplit() {
+ long i = index, delta = Long.highestOneBit((fence - i) - 1), m = i + delta;
+ if (m <= i) return null;
+ index = m;
+ ArbitrarilyJumpableRng r = (ArbitrarilyJumpableRng) generatingRng;
+ return new RandomIntsSpliterator(r.copyAndJump((double)delta), i, m, origin, bound);
+ }
+
+ public boolean tryAdvance(IntConsumer consumer) {
+ if (consumer == null) throw new NullPointerException();
+ long i = index, f = fence;
+ if (i < f) {
+ consumer.accept(RngSupport.boundedNextInt(generatingRng, origin, bound));
+ index = i + 1;
+ return true;
+ }
+ else return false;
+ }
+
+ public void forEachRemaining(IntConsumer consumer) {
+ if (consumer == null) throw new NullPointerException();
+ long i = index, f = fence;
+ if (i < f) {
+ index = f;
+ ArbitrarilyJumpableRng r = generatingRng;
+ int o = origin, b = bound;
+ do {
+ consumer.accept(RngSupport.boundedNextInt(r, o, b));
+ } while (++i < f);
+ }
+ }
+ }
+
+ /**
+ * Spliterator for long streams.
+ */
+ static class RandomLongsSpliterator extends RngSupport.RandomSpliterator implements Spliterator.OfLong {
+ final ArbitrarilyJumpableRng generatingRng;
+ final long origin;
+ final long bound;
+
+ RandomLongsSpliterator(ArbitrarilyJumpableRng generatingRng, long index, long fence, long origin, long bound) {
+ super(index, fence);
+ this.generatingRng = generatingRng;
+ this.origin = origin; this.bound = bound;
+ }
+
+ public Spliterator.OfLong trySplit() {
+ long i = index, delta = Long.highestOneBit((fence - i) - 1), m = i + delta;
+ if (m <= i) return null;
+ index = m;
+ ArbitrarilyJumpableRng r = (ArbitrarilyJumpableRng) generatingRng;
+ return new RandomLongsSpliterator(r.copyAndJump((double)delta), i, m, origin, bound);
+ }
+
+ public boolean tryAdvance(LongConsumer consumer) {
+ if (consumer == null) throw new NullPointerException();
+ long i = index, f = fence;
+ if (i < f) {
+ consumer.accept(RngSupport.boundedNextLong(generatingRng, origin, bound));
+ index = i + 1;
+ return true;
+ }
+ else return false;
+ }
+
+ public void forEachRemaining(LongConsumer consumer) {
+ if (consumer == null) throw new NullPointerException();
+ long i = index, f = fence;
+ if (i < f) {
+ index = f;
+ ArbitrarilyJumpableRng r = generatingRng;
+ long o = origin, b = bound;
+ do {
+ consumer.accept(RngSupport.boundedNextLong(r, o, b));
+ } while (++i < f);
+ }
+ }
+ }
+
+ /**
+ * Spliterator for double streams.
+ */
+ static class RandomDoublesSpliterator extends RngSupport.RandomSpliterator implements Spliterator.OfDouble {
+ final ArbitrarilyJumpableRng generatingRng;
+ final double origin;
+ final double bound;
+
+ RandomDoublesSpliterator(ArbitrarilyJumpableRng generatingRng, long index, long fence, double origin, double bound) {
+ super(index, fence);
+ this.generatingRng = generatingRng;
+ this.origin = origin; this.bound = bound;
+ }
+
+ public Spliterator.OfDouble trySplit() {
+
+ long i = index, delta = Long.highestOneBit((fence - i) - 1), m = i + delta;
+ if (m <= i) return null;
+ index = m;
+ ArbitrarilyJumpableRng r = (ArbitrarilyJumpableRng) generatingRng;
+ return new RandomDoublesSpliterator(r.copyAndJump((double)delta), i, m, origin, bound);
+ }
+
+ public boolean tryAdvance(DoubleConsumer consumer) {
+ if (consumer == null) throw new NullPointerException();
+ long i = index, f = fence;
+ if (i < f) {
+ consumer.accept(RngSupport.boundedNextDouble(generatingRng, origin, bound));
+ index = i + 1;
+ return true;
+ }
+ else return false;
+ }
+
+ public void forEachRemaining(DoubleConsumer consumer) {
+ if (consumer == null) throw new NullPointerException();
+ long i = index, f = fence;
+ if (i < f) {
+ index = f;
+ ArbitrarilyJumpableRng r = generatingRng;
+ double o = origin, b = bound;
+ do {
+ consumer.accept(RngSupport.boundedNextDouble(r, o, b));
+ } while (++i < f);
+ }
+ }
+ }
+
+ // Spliterators for producing new generators by jumping or leaping. The
+ // complete implementation of each of these spliterators is right here.
+ // In the same manner as for the preceding spliterators, the method trySplit() is
+ // coded to optimize execution speed: instead of dividing a range
+ // in half, it breaks off the largest possible chunk whose
+ // size is a power of two such that the remaining chunk is not
+ // empty. In this way, the necessary jump distances will tend to be
+ // powers of two.
+
+ /**
+ * Spliterator for stream of generators of type Rng produced by jumps.
+ */
+ static class RandomJumpsSpliterator extends RngSupport.RandomSpliterator implements Spliterator<Rng> {
+ ArbitrarilyJumpableRng generatingRng;
+ final double distance;
+
+ RandomJumpsSpliterator(ArbitrarilyJumpableRng generatingRng, long index, long fence, double distance) {
+ super(index, fence);
+ this.generatingRng = generatingRng; this.distance = distance;
+ }
+
+ public Spliterator<Rng> trySplit() {
+ long i = index, delta = Long.highestOneBit((fence - i) - 1), m = i + delta;
+ if (m <= i) return null;
+ index = m;
+ ArbitrarilyJumpableRng r = (ArbitrarilyJumpableRng) generatingRng;
+ // Because delta is a power of two, (distance * (double)delta) can always be computed exactly.
+ return new RandomJumpsSpliterator(r.copyAndJump(distance * (double)delta), i, m, distance);
+ }
+
+ public boolean tryAdvance(Consumer<? super Rng> consumer) {
+ if (consumer == null) throw new NullPointerException();
+ long i = index, f = fence;
+ if (i < f) {
+ consumer.accept(generatingRng.copyAndJump(distance));
+ index = i + 1;
+ return true;
+ }
+ return false;
+ }
+
+ public void forEachRemaining(Consumer<? super Rng> consumer) {
+ if (consumer == null) throw new NullPointerException();
+ long i = index, f = fence;
+ if (i < f) {
+ index = f;
+ ArbitrarilyJumpableRng r = generatingRng;
+ do {
+ consumer.accept(r.copyAndJump(distance));
+ } while (++i < f);
+ }
+ }
+ }
+
+ /**
+ * Spliterator for stream of generators of type Rng produced by leaps.
+ */
+ static class RandomLeapsSpliterator extends RngSupport.RandomSpliterator implements Spliterator<JumpableRng> {
+ ArbitrarilyJumpableRng generatingRng;
+ final double distance;
+
+ RandomLeapsSpliterator(ArbitrarilyJumpableRng generatingRng, long index, long fence, double distance) {
+ super(index, fence);
+ this.generatingRng = generatingRng; this.distance = distance;
+ }
+
+ public Spliterator<JumpableRng> trySplit() {
+ long i = index, delta = Long.highestOneBit((fence - i) - 1), m = i + delta;
+ if (m <= i) return null;
+ index = m;
+ // Because delta is a power of two, (distance * (double)delta) can always be computed exactly.
+ return new RandomLeapsSpliterator(generatingRng.copyAndJump(distance * (double)delta), i, m, distance);
+ }
+
+ public boolean tryAdvance(Consumer<? super JumpableRng> consumer) {
+ if (consumer == null) throw new NullPointerException();
+ long i = index, f = fence;
+ if (i < f) {
+ consumer.accept(generatingRng.copyAndJump(distance));
+ index = i + 1;
+ return true;
+ }
+ return false;
+ }
+
+ public void forEachRemaining(Consumer<? super JumpableRng> consumer) {
+ if (consumer == null) throw new NullPointerException();
+ long i = index, f = fence;
+ if (i < f) {
+ index = f;
+ ArbitrarilyJumpableRng r = generatingRng;
+ do {
+ consumer.accept(r.copyAndJump(distance));
+ } while (++i < f);
+ }
+ }
+ }
+
+ /**
+ * Spliterator for stream of generators of type Rng produced by arbitrary jumps.
+ */
+ static class RandomArbitraryJumpsSpliterator extends RngSupport.RandomSpliterator implements Spliterator<ArbitrarilyJumpableRng> {
+ ArbitrarilyJumpableRng generatingRng;
+ final double distance;
+
+ RandomArbitraryJumpsSpliterator(ArbitrarilyJumpableRng generatingRng, long index, long fence, double distance) {
+ super(index, fence);
+ this.generatingRng = generatingRng; this.distance = distance;
+ }
+
+ public Spliterator<ArbitrarilyJumpableRng> trySplit() {
+ long i = index, delta = Long.highestOneBit((fence - i) - 1), m = i + delta;
+ if (m <= i) return null;
+ index = m;
+ // Because delta is a power of two, (distance * (double)delta) can always be computed exactly.
+ return new RandomArbitraryJumpsSpliterator(generatingRng.copyAndJump(distance * (double)delta), i, m, distance);
+ }
+
+ public boolean tryAdvance(Consumer<? super ArbitrarilyJumpableRng> consumer) {
+ if (consumer == null) throw new NullPointerException();
+ long i = index, f = fence;
+ if (i < f) {
+ consumer.accept(generatingRng.copyAndJump(distance));
+ index = i + 1;
+ return true;
+ }
+ return false;
+ }
+
+ public void forEachRemaining(Consumer<? super ArbitrarilyJumpableRng> consumer) {
+ if (consumer == null) throw new NullPointerException();
+ long i = index, f = fence;
+ if (i < f) {
+ index = f;
+ ArbitrarilyJumpableRng r = generatingRng;
+ do {
+ consumer.accept(r.copyAndJump(distance));
+ } while (++i < f);
+ }
+ }
+ }
+
+}