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8202449: overflow handling in Random.doubles
Reviewed-by: darcy
This commit is contained in:
Raffaello Giulietti
Joe Darcy
parent
c15e10fb6c
commit
c8cff1bd6f
5 changed files with 82 additions and 71 deletions
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@ -256,7 +256,8 @@ public class Random implements RandomGenerator, java.io.Serializable {
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private static final long addend = 0xBL;
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private static final long mask = (1L << 48) - 1;
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private static final double DOUBLE_UNIT = 0x1.0p-53; // 1.0 / (1L << 53)
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private static final double DOUBLE_UNIT = 0x1.0p-53; // 1.0 / (1L << Double.PRECISION)
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private static final float FLOAT_UNIT = 0x1.0p-24f; // 1.0f / (1 << Float.PRECISION)
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/**
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* Creates a new random number generator. This constructor sets
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@ -598,12 +599,12 @@ public class Random implements RandomGenerator, java.io.Serializable {
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* low-order bit of the significand would be 0 than that it would be 1.]
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*
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* @return the next pseudorandom, uniformly distributed {@code float}
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* value between {@code 0.0} and {@code 1.0} from this
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* value between {@code 0.0f} and {@code 1.0f} from this
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* random number generator's sequence
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*/
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@Override
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public float nextFloat() {
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return next(24) / ((float)(1 << 24));
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return next(Float.PRECISION) * FLOAT_UNIT;
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}
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/**
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@ -644,7 +645,7 @@ public class Random implements RandomGenerator, java.io.Serializable {
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*/
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@Override
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public double nextDouble() {
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return (((long)(next(26)) << 27) + next(27)) * DOUBLE_UNIT;
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return (((long)(next(Double.PRECISION - 27)) << 27) + next(27)) * DOUBLE_UNIT;
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}
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private double nextNextGaussian;
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@ -1070,26 +1071,12 @@ public class Random implements RandomGenerator, java.io.Serializable {
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* pseudorandom {@code double} values, each conforming to the given origin
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* (inclusive) and bound (exclusive).
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*
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* <p>A pseudorandom {@code double} value is generated as if it's the result
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* of calling the following method with the origin and bound:
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* <pre> {@code
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* double nextDouble(double origin, double bound) {
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* double r = nextDouble();
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* r = r * (bound - origin) + origin;
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* if (r >= bound) // correct for rounding
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* r = Math.nextDown(bound);
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* return r;
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* }}</pre>
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*
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* @param streamSize the number of values to generate
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* @param randomNumberOrigin the origin (inclusive) of each random value
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* @param randomNumberBound the bound (exclusive) of each random value
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* @return a stream of pseudorandom {@code double} values,
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* each with the given origin (inclusive) and bound (exclusive)
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* @throws IllegalArgumentException if {@code streamSize} is less than zero,
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* or {@code randomNumberOrigin} is not finite,
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* or {@code randomNumberBound} is not finite, or {@code randomNumberOrigin}
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* is greater than or equal to {@code randomNumberBound}
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* @throws IllegalArgumentException {@inheritDoc}
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* @since 1.8
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*/
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@Override
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@ -1101,18 +1088,7 @@ public class Random implements RandomGenerator, java.io.Serializable {
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* Returns an effectively unlimited stream of pseudorandom {@code
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* double} values, each conforming to the given origin (inclusive) and bound
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* (exclusive).
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*
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* <p>A pseudorandom {@code double} value is generated as if it's the result
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* of calling the following method with the origin and bound:
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* <pre> {@code
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* double nextDouble(double origin, double bound) {
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* double r = nextDouble();
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* r = r * (bound - origin) + origin;
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* if (r >= bound) // correct for rounding
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* r = Math.nextDown(bound);
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* return r;
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* }}</pre>
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*
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* @implNote This method is implemented to be equivalent to {@code
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* doubles(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound)}.
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*
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@ -1120,8 +1096,7 @@ public class Random implements RandomGenerator, java.io.Serializable {
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* @param randomNumberBound the bound (exclusive) of each random value
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* @return a stream of pseudorandom {@code double} values,
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* each with the given origin (inclusive) and bound (exclusive)
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* @throws IllegalArgumentException if {@code randomNumberOrigin}
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* is greater than or equal to {@code randomNumberBound}
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* @throws IllegalArgumentException {@inheritDoc}
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* @since 1.8
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*/
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@Override
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@ -1,5 +1,5 @@
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/*
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* Copyright (c) 2013, 2021, Oracle and/or its affiliates. All rights reserved.
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* Copyright (c) 2013, 2022, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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@ -24,7 +24,6 @@
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*/
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package java.util;
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import java.math.BigInteger;
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import java.util.concurrent.atomic.AtomicLong;
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import java.util.random.RandomGenerator;
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import java.util.random.RandomGenerator.SplittableGenerator;
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@ -551,9 +550,7 @@ public final class SplittableRandom implements RandomGenerator, SplittableGenera
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* @param randomNumberBound the bound (exclusive) of each random value
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* @return a stream of pseudorandom {@code double} values,
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* each with the given origin (inclusive) and bound (exclusive)
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* @throws IllegalArgumentException if {@code streamSize} is
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* less than zero, or {@code randomNumberOrigin}
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* is greater than or equal to {@code randomNumberBound}
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* @throws IllegalArgumentException {@inheritDoc}
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*/
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@Override
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public DoubleStream doubles(long streamSize, double randomNumberOrigin, double randomNumberBound) {
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@ -572,8 +569,7 @@ public final class SplittableRandom implements RandomGenerator, SplittableGenera
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* @param randomNumberBound the bound (exclusive) of each random value
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* @return a stream of pseudorandom {@code double} values,
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* each with the given origin (inclusive) and bound (exclusive)
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* @throws IllegalArgumentException if {@code randomNumberOrigin}
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* is greater than or equal to {@code randomNumberBound}
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* @throws IllegalArgumentException {@inheritDoc}
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*/
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@Override
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public DoubleStream doubles(double randomNumberOrigin, double randomNumberBound) {
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@ -540,10 +540,7 @@ public interface RandomGenerator {
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*
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* @throws IllegalArgumentException if {@code origin} is not finite,
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* or {@code bound} is not finite, or {@code origin}
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* is greater than or equal to {@code bound}, or
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* the difference between {@code bound} and {@code origin}
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* is so large that it cannot be represented as a finite
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* {@code float} value
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* is greater than or equal to {@code bound}
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*
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* @implSpec The default implementation verifies that the {@code origin}
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* and {@code bound} are valid then invokes {@code nextFloat()}
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@ -606,11 +603,8 @@ public interface RandomGenerator {
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*
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* @throws IllegalArgumentException if {@code origin} is not finite,
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* or {@code bound} is not finite, or {@code origin}
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* is greater than or equal to {@code bound}, or
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* the difference between {@code bound} and {@code origin}
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* is so large that it cannot be represented as a finite
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* {@code double} value
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*
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* is greater than or equal to {@code bound}
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* @implSpec The default implementation verifies that the {@code origin}
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* and {@code bound} are valid, then invokes {@code nextDouble()}
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* scaling and translating the result to fit between {@code origin}
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