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jsr166 |
1.1 |
/* |
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* Written by Doug Lea with assistance from members of JCP JSR-166 |
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* Expert Group and released to the public domain, as explained at |
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jsr166 |
1.6 |
* http://creativecommons.org/publicdomain/zero/1.0/ |
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jsr166 |
1.1 |
*/ |
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package java.util.concurrent; |
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dl |
1.21 |
import java.security.SecureRandom; |
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import java.net.InetAddress; |
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dl |
1.9 |
import java.io.ObjectStreamField; |
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jsr166 |
1.1 |
import java.util.Random; |
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dl |
1.19 |
import java.util.Spliterator; |
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dl |
1.7 |
import java.util.concurrent.atomic.AtomicInteger; |
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import java.util.concurrent.atomic.AtomicLong; |
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dl |
1.19 |
import java.util.function.DoubleConsumer; |
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import java.util.function.IntConsumer; |
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import java.util.function.LongConsumer; |
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import java.util.stream.DoubleStream; |
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import java.util.stream.IntStream; |
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import java.util.stream.LongStream; |
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import java.util.stream.StreamSupport; |
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jsr166 |
1.1 |
|
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/** |
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jsr166 |
1.3 |
* A random number generator isolated to the current thread. Like the |
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jsr166 |
1.2 |
* global {@link java.util.Random} generator used by the {@link |
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jsr166 |
1.3 |
* java.lang.Math} class, a {@code ThreadLocalRandom} is initialized |
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* with an internally generated seed that may not otherwise be |
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* modified. When applicable, use of {@code ThreadLocalRandom} rather |
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* than shared {@code Random} objects in concurrent programs will |
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* typically encounter much less overhead and contention. Use of |
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* {@code ThreadLocalRandom} is particularly appropriate when multiple |
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* tasks (for example, each a {@link ForkJoinTask}) use random numbers |
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* in parallel in thread pools. |
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jsr166 |
1.1 |
* |
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* <p>Usages of this class should typically be of the form: |
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* {@code ThreadLocalRandom.current().nextX(...)} (where |
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* {@code X} is {@code Int}, {@code Long}, etc). |
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* When all usages are of this form, it is never possible to |
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jsr166 |
1.3 |
* accidently share a {@code ThreadLocalRandom} across multiple threads. |
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jsr166 |
1.1 |
* |
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* <p>This class also provides additional commonly used bounded random |
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* generation methods. |
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* |
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dl |
1.21 |
* <p>Instances of {@code ThreadLocalRandom} are not cryptographically |
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* secure. Consider instead using {@link java.security.SecureRandom} |
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dl |
1.23 |
* in security-sensitive applications. Additionally, |
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* default-constructed instances do not use a cryptographically random |
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* seed unless the {@linkplain System#getProperty system property} |
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* {@code java.util.secureRandomSeed} is set to {@code true}. |
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dl |
1.21 |
* |
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jsr166 |
1.1 |
* @since 1.7 |
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* @author Doug Lea |
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*/ |
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public class ThreadLocalRandom extends Random { |
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dl |
1.7 |
/* |
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* This class implements the java.util.Random API (and subclasses |
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* Random) using a single static instance that accesses random |
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* number state held in class Thread (primarily, field |
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* threadLocalRandomSeed). In doing so, it also provides a home |
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* for managing package-private utilities that rely on exactly the |
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* same state as needed to maintain the ThreadLocalRandom |
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* instances. We leverage the need for an initialization flag |
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* field to also use it as a "probe" -- a self-adjusting thread |
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* hash used for contention avoidance, as well as a secondary |
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* simpler (xorShift) random seed that is conservatively used to |
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* avoid otherwise surprising users by hijacking the |
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* ThreadLocalRandom sequence. The dual use is a marriage of |
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* convenience, but is a simple and efficient way of reducing |
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* application-level overhead and footprint of most concurrent |
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* programs. |
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* |
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dl |
1.19 |
* Even though this class subclasses java.util.Random, it uses the |
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* same basic algorithm as java.util.SplittableRandom. (See its |
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* internal documentation for explanations, which are not repeated |
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* here.) Because ThreadLocalRandoms are not splittable |
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* though, we use only a single 64bit gamma. |
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* |
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dl |
1.7 |
* Because this class is in a different package than class Thread, |
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jsr166 |
1.15 |
* field access methods use Unsafe to bypass access control rules. |
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dl |
1.19 |
* To conform to the requirements of the Random superclass |
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* constructor, the common static ThreadLocalRandom maintains an |
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* "initialized" field for the sake of rejecting user calls to |
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* setSeed while still allowing a call from constructor. Note |
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* that serialization is completely unnecessary because there is |
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* only a static singleton. But we generate a serial form |
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* containing "rnd" and "initialized" fields to ensure |
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* compatibility across versions. |
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* |
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* Implementations of non-core methods are mostly the same as in |
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* SplittableRandom, that were in part derived from a previous |
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* version of this class. |
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dl |
1.7 |
* |
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* The nextLocalGaussian ThreadLocal supports the very rarely used |
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* nextGaussian method by providing a holder for the second of a |
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* pair of them. As is true for the base class version of this |
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* method, this time/space tradeoff is probably never worthwhile, |
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* but we provide identical statistical properties. |
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*/ |
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dl |
1.19 |
/** Generates per-thread initialization/probe field */ |
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private static final AtomicInteger probeGenerator = |
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new AtomicInteger(); |
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jsr166 |
1.1 |
|
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dl |
1.19 |
/** |
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* The next seed for default constructors. |
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*/ |
108 |
dl |
1.23 |
private static final AtomicLong seeder = new AtomicLong(initialSeed()); |
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private static long initialSeed() { |
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String pp = java.security.AccessController.doPrivileged( |
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new sun.security.action.GetPropertyAction( |
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"java.util.secureRandomSeed")); |
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if (pp != null && pp.equalsIgnoreCase("true")) { |
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byte[] seedBytes = java.security.SecureRandom.getSeed(8); |
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long s = (long)(seedBytes[0]) & 0xffL; |
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for (int i = 1; i < 8; ++i) |
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s = (s << 8) | ((long)(seedBytes[i]) & 0xffL); |
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return s; |
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} |
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int hh = 0; // hashed host address |
122 |
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try { |
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hh = InetAddress.getLocalHost().hashCode(); |
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} catch (Exception ignore) { |
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} |
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return (mix64((((long)hh) << 32) ^ System.currentTimeMillis()) ^ |
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mix64(System.nanoTime())); |
128 |
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} |
129 |
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130 |
dl |
1.19 |
/** |
131 |
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* The seed increment |
132 |
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*/ |
133 |
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private static final long GAMMA = 0x9e3779b97f4a7c15L; |
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135 |
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/** |
136 |
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* The increment for generating probe values |
137 |
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*/ |
138 |
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private static final int PROBE_INCREMENT = 0x9e3779b9; |
139 |
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140 |
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/** |
141 |
dl |
1.21 |
* The increment of seeder per new instance |
142 |
dl |
1.19 |
*/ |
143 |
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private static final long SEEDER_INCREMENT = 0xbb67ae8584caa73bL; |
144 |
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145 |
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// Constants from SplittableRandom |
146 |
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private static final double DOUBLE_UNIT = 1.0 / (1L << 53); |
147 |
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private static final float FLOAT_UNIT = 1.0f / (1 << 24); |
148 |
jsr166 |
1.1 |
|
149 |
dl |
1.7 |
/** Rarely-used holder for the second of a pair of Gaussians */ |
150 |
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private static final ThreadLocal<Double> nextLocalGaussian = |
151 |
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new ThreadLocal<Double>(); |
152 |
jsr166 |
1.1 |
|
153 |
dl |
1.19 |
private static long mix64(long z) { |
154 |
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z = (z ^ (z >>> 33)) * 0xff51afd7ed558ccdL; |
155 |
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z = (z ^ (z >>> 33)) * 0xc4ceb9fe1a85ec53L; |
156 |
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return z ^ (z >>> 33); |
157 |
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} |
158 |
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159 |
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private static int mix32(long z) { |
160 |
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z = (z ^ (z >>> 33)) * 0xff51afd7ed558ccdL; |
161 |
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return (int)(((z ^ (z >>> 33)) * 0xc4ceb9fe1a85ec53L) >>> 32); |
162 |
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} |
163 |
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164 |
jsr166 |
1.11 |
/** |
165 |
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* Field used only during singleton initialization. |
166 |
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* True when constructor completes. |
167 |
jsr166 |
1.1 |
*/ |
168 |
jsr166 |
1.11 |
boolean initialized; |
169 |
dl |
1.7 |
|
170 |
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/** Constructor used only for static singleton */ |
171 |
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private ThreadLocalRandom() { |
172 |
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initialized = true; // false during super() call |
173 |
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} |
174 |
jsr166 |
1.1 |
|
175 |
dl |
1.7 |
/** The common ThreadLocalRandom */ |
176 |
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static final ThreadLocalRandom instance = new ThreadLocalRandom(); |
177 |
jsr166 |
1.1 |
|
178 |
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/** |
179 |
dl |
1.7 |
* Initialize Thread fields for the current thread. Called only |
180 |
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* when Thread.threadLocalRandomProbe is zero, indicating that a |
181 |
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* thread local seed value needs to be generated. Note that even |
182 |
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* though the initialization is purely thread-local, we need to |
183 |
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* rely on (static) atomic generators to initialize the values. |
184 |
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*/ |
185 |
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static final void localInit() { |
186 |
dl |
1.19 |
int p = probeGenerator.addAndGet(PROBE_INCREMENT); |
187 |
dl |
1.7 |
int probe = (p == 0) ? 1 : p; // skip 0 |
188 |
dl |
1.21 |
long seed = mix64(seeder.getAndAdd(SEEDER_INCREMENT)); |
189 |
dl |
1.7 |
Thread t = Thread.currentThread(); |
190 |
dl |
1.19 |
UNSAFE.putLong(t, SEED, seed); |
191 |
dl |
1.7 |
UNSAFE.putInt(t, PROBE, probe); |
192 |
jsr166 |
1.1 |
} |
193 |
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194 |
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/** |
195 |
jsr166 |
1.3 |
* Returns the current thread's {@code ThreadLocalRandom}. |
196 |
jsr166 |
1.1 |
* |
197 |
jsr166 |
1.3 |
* @return the current thread's {@code ThreadLocalRandom} |
198 |
jsr166 |
1.1 |
*/ |
199 |
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public static ThreadLocalRandom current() { |
200 |
dl |
1.7 |
if (UNSAFE.getInt(Thread.currentThread(), PROBE) == 0) |
201 |
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localInit(); |
202 |
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return instance; |
203 |
jsr166 |
1.1 |
} |
204 |
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205 |
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/** |
206 |
jsr166 |
1.3 |
* Throws {@code UnsupportedOperationException}. Setting seeds in |
207 |
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* this generator is not supported. |
208 |
jsr166 |
1.1 |
* |
209 |
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* @throws UnsupportedOperationException always |
210 |
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*/ |
211 |
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public void setSeed(long seed) { |
212 |
jsr166 |
1.15 |
// only allow call from super() constructor |
213 |
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if (initialized) |
214 |
jsr166 |
1.1 |
throw new UnsupportedOperationException(); |
215 |
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} |
216 |
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217 |
dl |
1.19 |
final long nextSeed() { |
218 |
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Thread t; long r; // read and update per-thread seed |
219 |
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UNSAFE.putLong(t = Thread.currentThread(), SEED, |
220 |
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r = UNSAFE.getLong(t, SEED) + GAMMA); |
221 |
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return r; |
222 |
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} |
223 |
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|
224 |
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// We must define this, but never use it. |
225 |
jsr166 |
1.1 |
protected int next(int bits) { |
226 |
dl |
1.19 |
return (int)(mix64(nextSeed()) >>> (64 - bits)); |
227 |
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} |
228 |
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229 |
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// IllegalArgumentException messages |
230 |
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static final String BadBound = "bound must be positive"; |
231 |
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static final String BadRange = "bound must be greater than origin"; |
232 |
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static final String BadSize = "size must be non-negative"; |
233 |
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234 |
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/** |
235 |
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* The form of nextLong used by LongStream Spliterators. If |
236 |
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* origin is greater than bound, acts as unbounded form of |
237 |
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* nextLong, else as bounded form. |
238 |
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* |
239 |
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* @param origin the least value, unless greater than bound |
240 |
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* @param bound the upper bound (exclusive), must not equal origin |
241 |
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* @return a pseudorandom value |
242 |
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*/ |
243 |
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final long internalNextLong(long origin, long bound) { |
244 |
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long r = mix64(nextSeed()); |
245 |
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if (origin < bound) { |
246 |
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long n = bound - origin, m = n - 1; |
247 |
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if ((n & m) == 0L) // power of two |
248 |
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r = (r & m) + origin; |
249 |
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else if (n > 0L) { // reject over-represented candidates |
250 |
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for (long u = r >>> 1; // ensure nonnegative |
251 |
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u + m - (r = u % n) < 0L; // rejection check |
252 |
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u = mix64(nextSeed()) >>> 1) // retry |
253 |
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; |
254 |
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r += origin; |
255 |
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} |
256 |
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else { // range not representable as long |
257 |
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while (r < origin || r >= bound) |
258 |
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r = mix64(nextSeed()); |
259 |
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} |
260 |
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} |
261 |
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return r; |
262 |
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} |
263 |
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264 |
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/** |
265 |
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* The form of nextInt used by IntStream Spliterators. |
266 |
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* Exactly the same as long version, except for types. |
267 |
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* |
268 |
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* @param origin the least value, unless greater than bound |
269 |
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* @param bound the upper bound (exclusive), must not equal origin |
270 |
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* @return a pseudorandom value |
271 |
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*/ |
272 |
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final int internalNextInt(int origin, int bound) { |
273 |
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int r = mix32(nextSeed()); |
274 |
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if (origin < bound) { |
275 |
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int n = bound - origin, m = n - 1; |
276 |
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if ((n & m) == 0) |
277 |
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r = (r & m) + origin; |
278 |
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else if (n > 0) { |
279 |
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for (int u = r >>> 1; |
280 |
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u + m - (r = u % n) < 0; |
281 |
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u = mix32(nextSeed()) >>> 1) |
282 |
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; |
283 |
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r += origin; |
284 |
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} |
285 |
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else { |
286 |
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while (r < origin || r >= bound) |
287 |
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r = mix32(nextSeed()); |
288 |
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} |
289 |
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} |
290 |
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return r; |
291 |
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} |
292 |
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|
293 |
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/** |
294 |
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* The form of nextDouble used by DoubleStream Spliterators. |
295 |
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* |
296 |
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* @param origin the least value, unless greater than bound |
297 |
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* @param bound the upper bound (exclusive), must not equal origin |
298 |
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* @return a pseudorandom value |
299 |
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*/ |
300 |
|
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final double internalNextDouble(double origin, double bound) { |
301 |
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double r = (nextLong() >>> 11) * DOUBLE_UNIT; |
302 |
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if (origin < bound) { |
303 |
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r = r * (bound - origin) + origin; |
304 |
|
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if (r >= bound) // correct for rounding |
305 |
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r = Double.longBitsToDouble(Double.doubleToLongBits(bound) - 1); |
306 |
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} |
307 |
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return r; |
308 |
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} |
309 |
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|
310 |
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/** |
311 |
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* Returns a pseudorandom {@code int} value. |
312 |
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* |
313 |
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* @return a pseudorandom {@code int} value |
314 |
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*/ |
315 |
|
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public int nextInt() { |
316 |
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return mix32(nextSeed()); |
317 |
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} |
318 |
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|
319 |
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/** |
320 |
|
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* Returns a pseudorandom {@code int} value between zero (inclusive) |
321 |
|
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* and the specified bound (exclusive). |
322 |
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* |
323 |
dl |
1.21 |
* @param bound the upper bound (exclusive). Must be positive. |
324 |
dl |
1.19 |
* @return a pseudorandom {@code int} value between zero |
325 |
|
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* (inclusive) and the bound (exclusive) |
326 |
dl |
1.20 |
* @throws IllegalArgumentException if {@code bound} is not positive |
327 |
dl |
1.19 |
*/ |
328 |
|
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public int nextInt(int bound) { |
329 |
|
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if (bound <= 0) |
330 |
|
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throw new IllegalArgumentException(BadBound); |
331 |
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int r = mix32(nextSeed()); |
332 |
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int m = bound - 1; |
333 |
|
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if ((bound & m) == 0) // power of two |
334 |
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r &= m; |
335 |
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else { // reject over-represented candidates |
336 |
|
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for (int u = r >>> 1; |
337 |
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u + m - (r = u % bound) < 0; |
338 |
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u = mix32(nextSeed()) >>> 1) |
339 |
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; |
340 |
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} |
341 |
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return r; |
342 |
jsr166 |
1.1 |
} |
343 |
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|
344 |
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/** |
345 |
dl |
1.19 |
* Returns a pseudorandom {@code int} value between the specified |
346 |
|
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* origin (inclusive) and the specified bound (exclusive). |
347 |
jsr166 |
1.1 |
* |
348 |
dl |
1.19 |
* @param origin the least value returned |
349 |
jsr166 |
1.1 |
* @param bound the upper bound (exclusive) |
350 |
dl |
1.19 |
* @return a pseudorandom {@code int} value between the origin |
351 |
|
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* (inclusive) and the bound (exclusive) |
352 |
|
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* @throws IllegalArgumentException if {@code origin} is greater than |
353 |
|
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* or equal to {@code bound} |
354 |
|
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*/ |
355 |
|
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public int nextInt(int origin, int bound) { |
356 |
|
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if (origin >= bound) |
357 |
|
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throw new IllegalArgumentException(BadRange); |
358 |
|
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return internalNextInt(origin, bound); |
359 |
|
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} |
360 |
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|
361 |
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/** |
362 |
|
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* Returns a pseudorandom {@code long} value. |
363 |
|
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* |
364 |
|
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* @return a pseudorandom {@code long} value |
365 |
jsr166 |
1.1 |
*/ |
366 |
dl |
1.19 |
public long nextLong() { |
367 |
|
|
return mix64(nextSeed()); |
368 |
jsr166 |
1.1 |
} |
369 |
|
|
|
370 |
|
|
/** |
371 |
dl |
1.19 |
* Returns a pseudorandom {@code long} value between zero (inclusive) |
372 |
|
|
* and the specified bound (exclusive). |
373 |
jsr166 |
1.1 |
* |
374 |
dl |
1.21 |
* @param bound the upper bound (exclusive). Must be positive. |
375 |
dl |
1.19 |
* @return a pseudorandom {@code long} value between zero |
376 |
|
|
* (inclusive) and the bound (exclusive) |
377 |
dl |
1.20 |
* @throws IllegalArgumentException if {@code bound} is not positive |
378 |
dl |
1.19 |
*/ |
379 |
|
|
public long nextLong(long bound) { |
380 |
|
|
if (bound <= 0) |
381 |
|
|
throw new IllegalArgumentException(BadBound); |
382 |
|
|
long r = mix64(nextSeed()); |
383 |
|
|
long m = bound - 1; |
384 |
|
|
if ((bound & m) == 0L) // power of two |
385 |
|
|
r &= m; |
386 |
|
|
else { // reject over-represented candidates |
387 |
|
|
for (long u = r >>> 1; |
388 |
|
|
u + m - (r = u % bound) < 0L; |
389 |
|
|
u = mix64(nextSeed()) >>> 1) |
390 |
|
|
; |
391 |
jsr166 |
1.1 |
} |
392 |
dl |
1.19 |
return r; |
393 |
jsr166 |
1.1 |
} |
394 |
|
|
|
395 |
|
|
/** |
396 |
dl |
1.19 |
* Returns a pseudorandom {@code long} value between the specified |
397 |
|
|
* origin (inclusive) and the specified bound (exclusive). |
398 |
jsr166 |
1.1 |
* |
399 |
dl |
1.19 |
* @param origin the least value returned |
400 |
jsr166 |
1.1 |
* @param bound the upper bound (exclusive) |
401 |
dl |
1.19 |
* @return a pseudorandom {@code long} value between the origin |
402 |
|
|
* (inclusive) and the bound (exclusive) |
403 |
|
|
* @throws IllegalArgumentException if {@code origin} is greater than |
404 |
|
|
* or equal to {@code bound} |
405 |
|
|
*/ |
406 |
|
|
public long nextLong(long origin, long bound) { |
407 |
|
|
if (origin >= bound) |
408 |
|
|
throw new IllegalArgumentException(BadRange); |
409 |
|
|
return internalNextLong(origin, bound); |
410 |
|
|
} |
411 |
|
|
|
412 |
|
|
/** |
413 |
|
|
* Returns a pseudorandom {@code double} value between zero |
414 |
|
|
* (inclusive) and one (exclusive). |
415 |
|
|
* |
416 |
|
|
* @return a pseudorandom {@code double} value between zero |
417 |
dl |
1.21 |
* (inclusive) and one (exclusive) |
418 |
jsr166 |
1.1 |
*/ |
419 |
dl |
1.19 |
public double nextDouble() { |
420 |
|
|
return (mix64(nextSeed()) >>> 11) * DOUBLE_UNIT; |
421 |
jsr166 |
1.1 |
} |
422 |
|
|
|
423 |
|
|
/** |
424 |
dl |
1.19 |
* Returns a pseudorandom {@code double} value between 0.0 |
425 |
|
|
* (inclusive) and the specified bound (exclusive). |
426 |
jsr166 |
1.1 |
* |
427 |
dl |
1.21 |
* @param bound the upper bound (exclusive). Must be positive. |
428 |
dl |
1.19 |
* @return a pseudorandom {@code double} value between zero |
429 |
|
|
* (inclusive) and the bound (exclusive) |
430 |
dl |
1.20 |
* @throws IllegalArgumentException if {@code bound} is not positive |
431 |
dl |
1.19 |
*/ |
432 |
|
|
public double nextDouble(double bound) { |
433 |
|
|
if (!(bound > 0.0)) |
434 |
|
|
throw new IllegalArgumentException(BadBound); |
435 |
|
|
double result = (mix64(nextSeed()) >>> 11) * DOUBLE_UNIT * bound; |
436 |
|
|
return (result < bound) ? result : // correct for rounding |
437 |
|
|
Double.longBitsToDouble(Double.doubleToLongBits(bound) - 1); |
438 |
|
|
} |
439 |
|
|
|
440 |
|
|
/** |
441 |
|
|
* Returns a pseudorandom {@code double} value between the specified |
442 |
|
|
* origin (inclusive) and bound (exclusive). |
443 |
|
|
* |
444 |
|
|
* @param origin the least value returned |
445 |
dl |
1.21 |
* @param bound the upper bound (exclusive) |
446 |
dl |
1.19 |
* @return a pseudorandom {@code double} value between the origin |
447 |
|
|
* (inclusive) and the bound (exclusive) |
448 |
|
|
* @throws IllegalArgumentException if {@code origin} is greater than |
449 |
|
|
* or equal to {@code bound} |
450 |
|
|
*/ |
451 |
|
|
public double nextDouble(double origin, double bound) { |
452 |
|
|
if (!(origin < bound)) |
453 |
|
|
throw new IllegalArgumentException(BadRange); |
454 |
|
|
return internalNextDouble(origin, bound); |
455 |
|
|
} |
456 |
|
|
|
457 |
|
|
/** |
458 |
|
|
* Returns a pseudorandom {@code boolean} value. |
459 |
|
|
* |
460 |
|
|
* @return a pseudorandom {@code boolean} value |
461 |
jsr166 |
1.1 |
*/ |
462 |
dl |
1.19 |
public boolean nextBoolean() { |
463 |
|
|
return mix32(nextSeed()) < 0; |
464 |
jsr166 |
1.1 |
} |
465 |
|
|
|
466 |
|
|
/** |
467 |
dl |
1.19 |
* Returns a pseudorandom {@code float} value between zero |
468 |
|
|
* (inclusive) and one (exclusive). |
469 |
jsr166 |
1.1 |
* |
470 |
dl |
1.19 |
* @return a pseudorandom {@code float} value between zero |
471 |
dl |
1.21 |
* (inclusive) and one (exclusive) |
472 |
dl |
1.19 |
*/ |
473 |
|
|
public float nextFloat() { |
474 |
|
|
return (mix32(nextSeed()) >>> 8) * FLOAT_UNIT; |
475 |
jsr166 |
1.1 |
} |
476 |
|
|
|
477 |
dl |
1.7 |
public double nextGaussian() { |
478 |
|
|
// Use nextLocalGaussian instead of nextGaussian field |
479 |
|
|
Double d = nextLocalGaussian.get(); |
480 |
|
|
if (d != null) { |
481 |
|
|
nextLocalGaussian.set(null); |
482 |
|
|
return d.doubleValue(); |
483 |
|
|
} |
484 |
|
|
double v1, v2, s; |
485 |
|
|
do { |
486 |
|
|
v1 = 2 * nextDouble() - 1; // between -1 and 1 |
487 |
|
|
v2 = 2 * nextDouble() - 1; // between -1 and 1 |
488 |
|
|
s = v1 * v1 + v2 * v2; |
489 |
|
|
} while (s >= 1 || s == 0); |
490 |
|
|
double multiplier = StrictMath.sqrt(-2 * StrictMath.log(s)/s); |
491 |
|
|
nextLocalGaussian.set(new Double(v2 * multiplier)); |
492 |
|
|
return v1 * multiplier; |
493 |
|
|
} |
494 |
|
|
|
495 |
dl |
1.19 |
// stream methods, coded in a way intended to better isolate for |
496 |
|
|
// maintenance purposes the small differences across forms. |
497 |
|
|
|
498 |
|
|
/** |
499 |
|
|
* Returns a stream producing the given {@code streamSize} number of |
500 |
|
|
* pseudorandom {@code int} values. |
501 |
|
|
* |
502 |
|
|
* @param streamSize the number of values to generate |
503 |
|
|
* @return a stream of pseudorandom {@code int} values |
504 |
|
|
* @throws IllegalArgumentException if {@code streamSize} is |
505 |
|
|
* less than zero |
506 |
dl |
1.21 |
* @since 1.8 |
507 |
dl |
1.19 |
*/ |
508 |
|
|
public IntStream ints(long streamSize) { |
509 |
|
|
if (streamSize < 0L) |
510 |
|
|
throw new IllegalArgumentException(BadSize); |
511 |
|
|
return StreamSupport.intStream |
512 |
|
|
(new RandomIntsSpliterator |
513 |
|
|
(0L, streamSize, Integer.MAX_VALUE, 0), |
514 |
|
|
false); |
515 |
|
|
} |
516 |
|
|
|
517 |
|
|
/** |
518 |
|
|
* Returns an effectively unlimited stream of pseudorandom {@code int} |
519 |
|
|
* values. |
520 |
|
|
* |
521 |
|
|
* @implNote This method is implemented to be equivalent to {@code |
522 |
|
|
* ints(Long.MAX_VALUE)}. |
523 |
|
|
* |
524 |
|
|
* @return a stream of pseudorandom {@code int} values |
525 |
dl |
1.21 |
* @since 1.8 |
526 |
dl |
1.19 |
*/ |
527 |
|
|
public IntStream ints() { |
528 |
|
|
return StreamSupport.intStream |
529 |
|
|
(new RandomIntsSpliterator |
530 |
|
|
(0L, Long.MAX_VALUE, Integer.MAX_VALUE, 0), |
531 |
|
|
false); |
532 |
|
|
} |
533 |
|
|
|
534 |
|
|
/** |
535 |
dl |
1.21 |
* Returns a stream producing the given {@code streamSize} number |
536 |
|
|
* of pseudorandom {@code int} values, each conforming to the given |
537 |
|
|
* origin (inclusive) and bound (exclusive). |
538 |
dl |
1.19 |
* |
539 |
|
|
* @param streamSize the number of values to generate |
540 |
dl |
1.21 |
* @param randomNumberOrigin the origin (inclusive) of each random value |
541 |
|
|
* @param randomNumberBound the bound (exclusive) of each random value |
542 |
dl |
1.19 |
* @return a stream of pseudorandom {@code int} values, |
543 |
dl |
1.21 |
* each with the given origin (inclusive) and bound (exclusive) |
544 |
dl |
1.19 |
* @throws IllegalArgumentException if {@code streamSize} is |
545 |
|
|
* less than zero, or {@code randomNumberOrigin} |
546 |
|
|
* is greater than or equal to {@code randomNumberBound} |
547 |
dl |
1.21 |
* @since 1.8 |
548 |
dl |
1.19 |
*/ |
549 |
|
|
public IntStream ints(long streamSize, int randomNumberOrigin, |
550 |
|
|
int randomNumberBound) { |
551 |
|
|
if (streamSize < 0L) |
552 |
|
|
throw new IllegalArgumentException(BadSize); |
553 |
|
|
if (randomNumberOrigin >= randomNumberBound) |
554 |
|
|
throw new IllegalArgumentException(BadRange); |
555 |
|
|
return StreamSupport.intStream |
556 |
|
|
(new RandomIntsSpliterator |
557 |
|
|
(0L, streamSize, randomNumberOrigin, randomNumberBound), |
558 |
|
|
false); |
559 |
|
|
} |
560 |
|
|
|
561 |
|
|
/** |
562 |
|
|
* Returns an effectively unlimited stream of pseudorandom {@code |
563 |
dl |
1.21 |
* int} values, each conforming to the given origin (inclusive) and bound |
564 |
|
|
* (exclusive). |
565 |
dl |
1.19 |
* |
566 |
|
|
* @implNote This method is implemented to be equivalent to {@code |
567 |
|
|
* ints(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound)}. |
568 |
|
|
* |
569 |
dl |
1.21 |
* @param randomNumberOrigin the origin (inclusive) of each random value |
570 |
|
|
* @param randomNumberBound the bound (exclusive) of each random value |
571 |
dl |
1.19 |
* @return a stream of pseudorandom {@code int} values, |
572 |
dl |
1.21 |
* each with the given origin (inclusive) and bound (exclusive) |
573 |
dl |
1.19 |
* @throws IllegalArgumentException if {@code randomNumberOrigin} |
574 |
|
|
* is greater than or equal to {@code randomNumberBound} |
575 |
dl |
1.21 |
* @since 1.8 |
576 |
dl |
1.19 |
*/ |
577 |
|
|
public IntStream ints(int randomNumberOrigin, int randomNumberBound) { |
578 |
|
|
if (randomNumberOrigin >= randomNumberBound) |
579 |
|
|
throw new IllegalArgumentException(BadRange); |
580 |
|
|
return StreamSupport.intStream |
581 |
|
|
(new RandomIntsSpliterator |
582 |
|
|
(0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound), |
583 |
|
|
false); |
584 |
|
|
} |
585 |
|
|
|
586 |
|
|
/** |
587 |
|
|
* Returns a stream producing the given {@code streamSize} number of |
588 |
|
|
* pseudorandom {@code long} values. |
589 |
|
|
* |
590 |
|
|
* @param streamSize the number of values to generate |
591 |
|
|
* @return a stream of pseudorandom {@code long} values |
592 |
|
|
* @throws IllegalArgumentException if {@code streamSize} is |
593 |
|
|
* less than zero |
594 |
dl |
1.21 |
* @since 1.8 |
595 |
dl |
1.19 |
*/ |
596 |
|
|
public LongStream longs(long streamSize) { |
597 |
|
|
if (streamSize < 0L) |
598 |
|
|
throw new IllegalArgumentException(BadSize); |
599 |
|
|
return StreamSupport.longStream |
600 |
|
|
(new RandomLongsSpliterator |
601 |
|
|
(0L, streamSize, Long.MAX_VALUE, 0L), |
602 |
|
|
false); |
603 |
|
|
} |
604 |
|
|
|
605 |
|
|
/** |
606 |
|
|
* Returns an effectively unlimited stream of pseudorandom {@code long} |
607 |
|
|
* values. |
608 |
|
|
* |
609 |
|
|
* @implNote This method is implemented to be equivalent to {@code |
610 |
|
|
* longs(Long.MAX_VALUE)}. |
611 |
|
|
* |
612 |
|
|
* @return a stream of pseudorandom {@code long} values |
613 |
dl |
1.21 |
* @since 1.8 |
614 |
dl |
1.19 |
*/ |
615 |
|
|
public LongStream longs() { |
616 |
|
|
return StreamSupport.longStream |
617 |
|
|
(new RandomLongsSpliterator |
618 |
|
|
(0L, Long.MAX_VALUE, Long.MAX_VALUE, 0L), |
619 |
|
|
false); |
620 |
|
|
} |
621 |
|
|
|
622 |
|
|
/** |
623 |
|
|
* Returns a stream producing the given {@code streamSize} number of |
624 |
dl |
1.21 |
* pseudorandom {@code long}, each conforming to the given origin |
625 |
|
|
* (inclusive) and bound (exclusive). |
626 |
dl |
1.19 |
* |
627 |
|
|
* @param streamSize the number of values to generate |
628 |
dl |
1.21 |
* @param randomNumberOrigin the origin (inclusive) of each random value |
629 |
|
|
* @param randomNumberBound the bound (exclusive) of each random value |
630 |
dl |
1.19 |
* @return a stream of pseudorandom {@code long} values, |
631 |
dl |
1.21 |
* each with the given origin (inclusive) and bound (exclusive) |
632 |
dl |
1.19 |
* @throws IllegalArgumentException if {@code streamSize} is |
633 |
|
|
* less than zero, or {@code randomNumberOrigin} |
634 |
|
|
* is greater than or equal to {@code randomNumberBound} |
635 |
dl |
1.21 |
* @since 1.8 |
636 |
dl |
1.19 |
*/ |
637 |
|
|
public LongStream longs(long streamSize, long randomNumberOrigin, |
638 |
|
|
long randomNumberBound) { |
639 |
|
|
if (streamSize < 0L) |
640 |
|
|
throw new IllegalArgumentException(BadSize); |
641 |
|
|
if (randomNumberOrigin >= randomNumberBound) |
642 |
|
|
throw new IllegalArgumentException(BadRange); |
643 |
|
|
return StreamSupport.longStream |
644 |
|
|
(new RandomLongsSpliterator |
645 |
|
|
(0L, streamSize, randomNumberOrigin, randomNumberBound), |
646 |
|
|
false); |
647 |
|
|
} |
648 |
|
|
|
649 |
|
|
/** |
650 |
|
|
* Returns an effectively unlimited stream of pseudorandom {@code |
651 |
dl |
1.21 |
* long} values, each conforming to the given origin (inclusive) and bound |
652 |
|
|
* (exclusive). |
653 |
dl |
1.19 |
* |
654 |
|
|
* @implNote This method is implemented to be equivalent to {@code |
655 |
|
|
* longs(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound)}. |
656 |
|
|
* |
657 |
dl |
1.21 |
* @param randomNumberOrigin the origin (inclusive) of each random value |
658 |
|
|
* @param randomNumberBound the bound (exclusive) of each random value |
659 |
dl |
1.19 |
* @return a stream of pseudorandom {@code long} values, |
660 |
dl |
1.21 |
* each with the given origin (inclusive) and bound (exclusive) |
661 |
dl |
1.19 |
* @throws IllegalArgumentException if {@code randomNumberOrigin} |
662 |
|
|
* is greater than or equal to {@code randomNumberBound} |
663 |
dl |
1.21 |
* @since 1.8 |
664 |
dl |
1.19 |
*/ |
665 |
|
|
public LongStream longs(long randomNumberOrigin, long randomNumberBound) { |
666 |
|
|
if (randomNumberOrigin >= randomNumberBound) |
667 |
|
|
throw new IllegalArgumentException(BadRange); |
668 |
|
|
return StreamSupport.longStream |
669 |
|
|
(new RandomLongsSpliterator |
670 |
|
|
(0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound), |
671 |
|
|
false); |
672 |
|
|
} |
673 |
|
|
|
674 |
|
|
/** |
675 |
|
|
* Returns a stream producing the given {@code streamSize} number of |
676 |
|
|
* pseudorandom {@code double} values, each between zero |
677 |
|
|
* (inclusive) and one (exclusive). |
678 |
|
|
* |
679 |
|
|
* @param streamSize the number of values to generate |
680 |
|
|
* @return a stream of {@code double} values |
681 |
|
|
* @throws IllegalArgumentException if {@code streamSize} is |
682 |
|
|
* less than zero |
683 |
dl |
1.21 |
* @since 1.8 |
684 |
dl |
1.19 |
*/ |
685 |
|
|
public DoubleStream doubles(long streamSize) { |
686 |
|
|
if (streamSize < 0L) |
687 |
|
|
throw new IllegalArgumentException(BadSize); |
688 |
|
|
return StreamSupport.doubleStream |
689 |
|
|
(new RandomDoublesSpliterator |
690 |
|
|
(0L, streamSize, Double.MAX_VALUE, 0.0), |
691 |
|
|
false); |
692 |
|
|
} |
693 |
|
|
|
694 |
|
|
/** |
695 |
|
|
* Returns an effectively unlimited stream of pseudorandom {@code |
696 |
|
|
* double} values, each between zero (inclusive) and one |
697 |
|
|
* (exclusive). |
698 |
|
|
* |
699 |
|
|
* @implNote This method is implemented to be equivalent to {@code |
700 |
|
|
* doubles(Long.MAX_VALUE)}. |
701 |
|
|
* |
702 |
|
|
* @return a stream of pseudorandom {@code double} values |
703 |
dl |
1.21 |
* @since 1.8 |
704 |
dl |
1.19 |
*/ |
705 |
|
|
public DoubleStream doubles() { |
706 |
|
|
return StreamSupport.doubleStream |
707 |
|
|
(new RandomDoublesSpliterator |
708 |
|
|
(0L, Long.MAX_VALUE, Double.MAX_VALUE, 0.0), |
709 |
|
|
false); |
710 |
|
|
} |
711 |
|
|
|
712 |
|
|
/** |
713 |
|
|
* Returns a stream producing the given {@code streamSize} number of |
714 |
dl |
1.21 |
* pseudorandom {@code double} values, each conforming to the given origin |
715 |
|
|
* (inclusive) and bound (exclusive). |
716 |
dl |
1.19 |
* |
717 |
|
|
* @param streamSize the number of values to generate |
718 |
dl |
1.21 |
* @param randomNumberOrigin the origin (inclusive) of each random value |
719 |
|
|
* @param randomNumberBound the bound (exclusive) of each random value |
720 |
dl |
1.19 |
* @return a stream of pseudorandom {@code double} values, |
721 |
dl |
1.21 |
* each with the given origin (inclusive) and bound (exclusive) |
722 |
dl |
1.19 |
* @throws IllegalArgumentException if {@code streamSize} is |
723 |
dl |
1.21 |
* less than zero |
724 |
dl |
1.19 |
* @throws IllegalArgumentException if {@code randomNumberOrigin} |
725 |
|
|
* is greater than or equal to {@code randomNumberBound} |
726 |
dl |
1.21 |
* @since 1.8 |
727 |
dl |
1.19 |
*/ |
728 |
|
|
public DoubleStream doubles(long streamSize, double randomNumberOrigin, |
729 |
|
|
double randomNumberBound) { |
730 |
|
|
if (streamSize < 0L) |
731 |
|
|
throw new IllegalArgumentException(BadSize); |
732 |
|
|
if (!(randomNumberOrigin < randomNumberBound)) |
733 |
|
|
throw new IllegalArgumentException(BadRange); |
734 |
|
|
return StreamSupport.doubleStream |
735 |
|
|
(new RandomDoublesSpliterator |
736 |
|
|
(0L, streamSize, randomNumberOrigin, randomNumberBound), |
737 |
|
|
false); |
738 |
|
|
} |
739 |
|
|
|
740 |
|
|
/** |
741 |
|
|
* Returns an effectively unlimited stream of pseudorandom {@code |
742 |
dl |
1.21 |
* double} values, each conforming to the given origin (inclusive) and bound |
743 |
|
|
* (exclusive). |
744 |
dl |
1.19 |
* |
745 |
|
|
* @implNote This method is implemented to be equivalent to {@code |
746 |
|
|
* doubles(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound)}. |
747 |
|
|
* |
748 |
dl |
1.21 |
* @param randomNumberOrigin the origin (inclusive) of each random value |
749 |
|
|
* @param randomNumberBound the bound (exclusive) of each random value |
750 |
dl |
1.19 |
* @return a stream of pseudorandom {@code double} values, |
751 |
dl |
1.21 |
* each with the given origin (inclusive) and bound (exclusive) |
752 |
dl |
1.19 |
* @throws IllegalArgumentException if {@code randomNumberOrigin} |
753 |
|
|
* is greater than or equal to {@code randomNumberBound} |
754 |
dl |
1.21 |
* @since 1.8 |
755 |
dl |
1.19 |
*/ |
756 |
|
|
public DoubleStream doubles(double randomNumberOrigin, double randomNumberBound) { |
757 |
|
|
if (!(randomNumberOrigin < randomNumberBound)) |
758 |
|
|
throw new IllegalArgumentException(BadRange); |
759 |
|
|
return StreamSupport.doubleStream |
760 |
|
|
(new RandomDoublesSpliterator |
761 |
|
|
(0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound), |
762 |
|
|
false); |
763 |
|
|
} |
764 |
|
|
|
765 |
|
|
/** |
766 |
|
|
* Spliterator for int streams. We multiplex the four int |
767 |
|
|
* versions into one class by treating a bound less than origin as |
768 |
|
|
* unbounded, and also by treating "infinite" as equivalent to |
769 |
|
|
* Long.MAX_VALUE. For splits, it uses the standard divide-by-two |
770 |
|
|
* approach. The long and double versions of this class are |
771 |
|
|
* identical except for types. |
772 |
|
|
*/ |
773 |
|
|
static final class RandomIntsSpliterator implements Spliterator.OfInt { |
774 |
|
|
long index; |
775 |
|
|
final long fence; |
776 |
|
|
final int origin; |
777 |
|
|
final int bound; |
778 |
|
|
RandomIntsSpliterator(long index, long fence, |
779 |
|
|
int origin, int bound) { |
780 |
|
|
this.index = index; this.fence = fence; |
781 |
|
|
this.origin = origin; this.bound = bound; |
782 |
|
|
} |
783 |
|
|
|
784 |
|
|
public RandomIntsSpliterator trySplit() { |
785 |
|
|
long i = index, m = (i + fence) >>> 1; |
786 |
|
|
return (m <= i) ? null : |
787 |
|
|
new RandomIntsSpliterator(i, index = m, origin, bound); |
788 |
|
|
} |
789 |
|
|
|
790 |
|
|
public long estimateSize() { |
791 |
|
|
return fence - index; |
792 |
|
|
} |
793 |
|
|
|
794 |
|
|
public int characteristics() { |
795 |
|
|
return (Spliterator.SIZED | Spliterator.SUBSIZED | |
796 |
|
|
Spliterator.NONNULL | Spliterator.IMMUTABLE); |
797 |
|
|
} |
798 |
|
|
|
799 |
|
|
public boolean tryAdvance(IntConsumer consumer) { |
800 |
|
|
if (consumer == null) throw new NullPointerException(); |
801 |
|
|
long i = index, f = fence; |
802 |
|
|
if (i < f) { |
803 |
|
|
consumer.accept(ThreadLocalRandom.current().internalNextInt(origin, bound)); |
804 |
|
|
index = i + 1; |
805 |
|
|
return true; |
806 |
|
|
} |
807 |
|
|
return false; |
808 |
|
|
} |
809 |
|
|
|
810 |
|
|
public void forEachRemaining(IntConsumer consumer) { |
811 |
|
|
if (consumer == null) throw new NullPointerException(); |
812 |
|
|
long i = index, f = fence; |
813 |
|
|
if (i < f) { |
814 |
|
|
index = f; |
815 |
|
|
int o = origin, b = bound; |
816 |
|
|
ThreadLocalRandom rng = ThreadLocalRandom.current(); |
817 |
|
|
do { |
818 |
|
|
consumer.accept(rng.internalNextInt(o, b)); |
819 |
|
|
} while (++i < f); |
820 |
|
|
} |
821 |
|
|
} |
822 |
|
|
} |
823 |
|
|
|
824 |
|
|
/** |
825 |
|
|
* Spliterator for long streams. |
826 |
|
|
*/ |
827 |
|
|
static final class RandomLongsSpliterator implements Spliterator.OfLong { |
828 |
|
|
long index; |
829 |
|
|
final long fence; |
830 |
|
|
final long origin; |
831 |
|
|
final long bound; |
832 |
|
|
RandomLongsSpliterator(long index, long fence, |
833 |
|
|
long origin, long bound) { |
834 |
|
|
this.index = index; this.fence = fence; |
835 |
|
|
this.origin = origin; this.bound = bound; |
836 |
|
|
} |
837 |
|
|
|
838 |
|
|
public RandomLongsSpliterator trySplit() { |
839 |
|
|
long i = index, m = (i + fence) >>> 1; |
840 |
|
|
return (m <= i) ? null : |
841 |
|
|
new RandomLongsSpliterator(i, index = m, origin, bound); |
842 |
|
|
} |
843 |
|
|
|
844 |
|
|
public long estimateSize() { |
845 |
|
|
return fence - index; |
846 |
|
|
} |
847 |
|
|
|
848 |
|
|
public int characteristics() { |
849 |
|
|
return (Spliterator.SIZED | Spliterator.SUBSIZED | |
850 |
|
|
Spliterator.NONNULL | Spliterator.IMMUTABLE); |
851 |
|
|
} |
852 |
|
|
|
853 |
|
|
public boolean tryAdvance(LongConsumer consumer) { |
854 |
|
|
if (consumer == null) throw new NullPointerException(); |
855 |
|
|
long i = index, f = fence; |
856 |
|
|
if (i < f) { |
857 |
|
|
consumer.accept(ThreadLocalRandom.current().internalNextLong(origin, bound)); |
858 |
|
|
index = i + 1; |
859 |
|
|
return true; |
860 |
|
|
} |
861 |
|
|
return false; |
862 |
|
|
} |
863 |
|
|
|
864 |
|
|
public void forEachRemaining(LongConsumer consumer) { |
865 |
|
|
if (consumer == null) throw new NullPointerException(); |
866 |
|
|
long i = index, f = fence; |
867 |
|
|
if (i < f) { |
868 |
|
|
index = f; |
869 |
|
|
long o = origin, b = bound; |
870 |
|
|
ThreadLocalRandom rng = ThreadLocalRandom.current(); |
871 |
|
|
do { |
872 |
|
|
consumer.accept(rng.internalNextLong(o, b)); |
873 |
|
|
} while (++i < f); |
874 |
|
|
} |
875 |
|
|
} |
876 |
|
|
|
877 |
|
|
} |
878 |
|
|
|
879 |
|
|
/** |
880 |
|
|
* Spliterator for double streams. |
881 |
|
|
*/ |
882 |
|
|
static final class RandomDoublesSpliterator implements Spliterator.OfDouble { |
883 |
|
|
long index; |
884 |
|
|
final long fence; |
885 |
|
|
final double origin; |
886 |
|
|
final double bound; |
887 |
|
|
RandomDoublesSpliterator(long index, long fence, |
888 |
|
|
double origin, double bound) { |
889 |
|
|
this.index = index; this.fence = fence; |
890 |
|
|
this.origin = origin; this.bound = bound; |
891 |
|
|
} |
892 |
|
|
|
893 |
|
|
public RandomDoublesSpliterator trySplit() { |
894 |
|
|
long i = index, m = (i + fence) >>> 1; |
895 |
|
|
return (m <= i) ? null : |
896 |
|
|
new RandomDoublesSpliterator(i, index = m, origin, bound); |
897 |
|
|
} |
898 |
|
|
|
899 |
|
|
public long estimateSize() { |
900 |
|
|
return fence - index; |
901 |
|
|
} |
902 |
|
|
|
903 |
|
|
public int characteristics() { |
904 |
|
|
return (Spliterator.SIZED | Spliterator.SUBSIZED | |
905 |
|
|
Spliterator.NONNULL | Spliterator.IMMUTABLE); |
906 |
|
|
} |
907 |
|
|
|
908 |
|
|
public boolean tryAdvance(DoubleConsumer consumer) { |
909 |
|
|
if (consumer == null) throw new NullPointerException(); |
910 |
|
|
long i = index, f = fence; |
911 |
|
|
if (i < f) { |
912 |
|
|
consumer.accept(ThreadLocalRandom.current().internalNextDouble(origin, bound)); |
913 |
|
|
index = i + 1; |
914 |
|
|
return true; |
915 |
|
|
} |
916 |
|
|
return false; |
917 |
|
|
} |
918 |
|
|
|
919 |
|
|
public void forEachRemaining(DoubleConsumer consumer) { |
920 |
|
|
if (consumer == null) throw new NullPointerException(); |
921 |
|
|
long i = index, f = fence; |
922 |
|
|
if (i < f) { |
923 |
|
|
index = f; |
924 |
|
|
double o = origin, b = bound; |
925 |
|
|
ThreadLocalRandom rng = ThreadLocalRandom.current(); |
926 |
|
|
do { |
927 |
|
|
consumer.accept(rng.internalNextDouble(o, b)); |
928 |
|
|
} while (++i < f); |
929 |
|
|
} |
930 |
|
|
} |
931 |
|
|
} |
932 |
|
|
|
933 |
|
|
|
934 |
dl |
1.7 |
// Within-package utilities |
935 |
|
|
|
936 |
|
|
/* |
937 |
|
|
* Descriptions of the usages of the methods below can be found in |
938 |
|
|
* the classes that use them. Briefly, a thread's "probe" value is |
939 |
|
|
* a non-zero hash code that (probably) does not collide with |
940 |
|
|
* other existing threads with respect to any power of two |
941 |
|
|
* collision space. When it does collide, it is pseudo-randomly |
942 |
|
|
* adjusted (using a Marsaglia XorShift). The nextSecondarySeed |
943 |
|
|
* method is used in the same contexts as ThreadLocalRandom, but |
944 |
|
|
* only for transient usages such as random adaptive spin/block |
945 |
|
|
* sequences for which a cheap RNG suffices and for which it could |
946 |
|
|
* in principle disrupt user-visible statistical properties of the |
947 |
|
|
* main ThreadLocalRandom if we were to use it. |
948 |
|
|
* |
949 |
|
|
* Note: Because of package-protection issues, versions of some |
950 |
dl |
1.9 |
* these methods also appear in some subpackage classes. |
951 |
dl |
1.7 |
*/ |
952 |
|
|
|
953 |
|
|
/** |
954 |
|
|
* Returns the probe value for the current thread without forcing |
955 |
|
|
* initialization. Note that invoking ThreadLocalRandom.current() |
956 |
|
|
* can be used to force initialization on zero return. |
957 |
|
|
*/ |
958 |
|
|
static final int getProbe() { |
959 |
|
|
return UNSAFE.getInt(Thread.currentThread(), PROBE); |
960 |
|
|
} |
961 |
|
|
|
962 |
|
|
/** |
963 |
|
|
* Pseudo-randomly advances and records the given probe value for the |
964 |
|
|
* given thread. |
965 |
|
|
*/ |
966 |
|
|
static final int advanceProbe(int probe) { |
967 |
|
|
probe ^= probe << 13; // xorshift |
968 |
|
|
probe ^= probe >>> 17; |
969 |
|
|
probe ^= probe << 5; |
970 |
|
|
UNSAFE.putInt(Thread.currentThread(), PROBE, probe); |
971 |
|
|
return probe; |
972 |
|
|
} |
973 |
|
|
|
974 |
|
|
/** |
975 |
|
|
* Returns the pseudo-randomly initialized or updated secondary seed. |
976 |
|
|
*/ |
977 |
|
|
static final int nextSecondarySeed() { |
978 |
|
|
int r; |
979 |
|
|
Thread t = Thread.currentThread(); |
980 |
|
|
if ((r = UNSAFE.getInt(t, SECONDARY)) != 0) { |
981 |
|
|
r ^= r << 13; // xorshift |
982 |
|
|
r ^= r >>> 17; |
983 |
|
|
r ^= r << 5; |
984 |
|
|
} |
985 |
dl |
1.10 |
else { |
986 |
|
|
localInit(); |
987 |
|
|
if ((r = (int)UNSAFE.getLong(t, SEED)) == 0) |
988 |
|
|
r = 1; // avoid zero |
989 |
|
|
} |
990 |
dl |
1.7 |
UNSAFE.putInt(t, SECONDARY, r); |
991 |
|
|
return r; |
992 |
|
|
} |
993 |
|
|
|
994 |
jsr166 |
1.13 |
// Serialization support |
995 |
dl |
1.9 |
|
996 |
jsr166 |
1.1 |
private static final long serialVersionUID = -5851777807851030925L; |
997 |
dl |
1.7 |
|
998 |
dl |
1.9 |
/** |
999 |
jsr166 |
1.14 |
* @serialField rnd long |
1000 |
|
|
* seed for random computations |
1001 |
|
|
* @serialField initialized boolean |
1002 |
|
|
* always true |
1003 |
|
|
*/ |
1004 |
|
|
private static final ObjectStreamField[] serialPersistentFields = { |
1005 |
|
|
new ObjectStreamField("rnd", long.class), |
1006 |
|
|
new ObjectStreamField("initialized", boolean.class), |
1007 |
|
|
}; |
1008 |
|
|
|
1009 |
|
|
/** |
1010 |
|
|
* Saves the {@code ThreadLocalRandom} to a stream (that is, serializes it). |
1011 |
jsr166 |
1.16 |
* @param s the stream |
1012 |
jsr166 |
1.17 |
* @throws java.io.IOException if an I/O error occurs |
1013 |
jsr166 |
1.14 |
*/ |
1014 |
jsr166 |
1.16 |
private void writeObject(java.io.ObjectOutputStream s) |
1015 |
jsr166 |
1.14 |
throws java.io.IOException { |
1016 |
|
|
|
1017 |
jsr166 |
1.16 |
java.io.ObjectOutputStream.PutField fields = s.putFields(); |
1018 |
jsr166 |
1.14 |
fields.put("rnd", UNSAFE.getLong(Thread.currentThread(), SEED)); |
1019 |
|
|
fields.put("initialized", true); |
1020 |
jsr166 |
1.16 |
s.writeFields(); |
1021 |
jsr166 |
1.14 |
} |
1022 |
|
|
|
1023 |
|
|
/** |
1024 |
dl |
1.9 |
* Returns the {@link #current() current} thread's {@code ThreadLocalRandom}. |
1025 |
jsr166 |
1.16 |
* @return the {@link #current() current} thread's {@code ThreadLocalRandom} |
1026 |
dl |
1.9 |
*/ |
1027 |
|
|
private Object readResolve() { |
1028 |
|
|
return current(); |
1029 |
|
|
} |
1030 |
|
|
|
1031 |
dl |
1.7 |
// Unsafe mechanics |
1032 |
|
|
private static final sun.misc.Unsafe UNSAFE; |
1033 |
|
|
private static final long SEED; |
1034 |
|
|
private static final long PROBE; |
1035 |
|
|
private static final long SECONDARY; |
1036 |
|
|
static { |
1037 |
|
|
try { |
1038 |
|
|
UNSAFE = sun.misc.Unsafe.getUnsafe(); |
1039 |
|
|
Class<?> tk = Thread.class; |
1040 |
|
|
SEED = UNSAFE.objectFieldOffset |
1041 |
|
|
(tk.getDeclaredField("threadLocalRandomSeed")); |
1042 |
|
|
PROBE = UNSAFE.objectFieldOffset |
1043 |
|
|
(tk.getDeclaredField("threadLocalRandomProbe")); |
1044 |
|
|
SECONDARY = UNSAFE.objectFieldOffset |
1045 |
|
|
(tk.getDeclaredField("threadLocalRandomSecondarySeed")); |
1046 |
|
|
} catch (Exception e) { |
1047 |
|
|
throw new Error(e); |
1048 |
|
|
} |
1049 |
|
|
} |
1050 |
jsr166 |
1.1 |
} |