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package java.util; |
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import java.net.InetAddress; |
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import java.util.concurrent.atomic.AtomicLong; |
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import java.util.Spliterator; |
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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.function.DoubleConsumer; |
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import java.util.stream.StreamSupport; |
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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.DoubleStream; |
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import java.util.stream.StreamSupport; |
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|
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/** |
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* A generator of uniform pseudorandom values applicable for use in |
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* (among other contexts) isolated parallel computations that may |
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* generate subtasks. Class SplittableRandom supports methods for |
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* generate subtasks. Class {@code SplittableRandom} supports methods for |
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* producing pseudorandom numbers of type {@code int}, {@code long}, |
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* and {@code double} with similar usages as for class |
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* {@link java.util.Random} but differs in the following ways: |
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* types and ranges, but similar properties are expected to hold, at |
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* least approximately, for others as well. The <em>period</em> |
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* (length of any series of generated values before it repeats) is at |
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* least 2<sup>64</sup>. </li> |
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* least 2<sup>64</sup>. |
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* |
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* <li> Method {@link #split} constructs and returns a new |
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* <li>Method {@link #split} constructs and returns a new |
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* SplittableRandom instance that shares no mutable state with the |
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* current instance. However, with very high probability, the |
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* values collectively generated by the two objects have the same |
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* statistical properties as if the same quantity of values were |
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* generated by a single thread using a single {@code |
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* SplittableRandom} object. </li> |
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* SplittableRandom} object. |
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* |
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* <li>Instances of SplittableRandom are <em>not</em> thread-safe. |
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* They are designed to be split, not shared, across threads. For |
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* |
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* <li>This class provides additional methods for generating random |
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* streams, that employ the above techniques when used in {@code |
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* stream.parallel()} mode.</li> |
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* stream.parallel()} mode. |
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* |
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* </ul> |
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* |
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* <p>Instances of {@code SplittableRandom} are not cryptographically |
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* secure. Consider instead using {@link java.security.SecureRandom} |
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* 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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* |
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* @author Guy Steele |
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* @author Doug Lea |
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* @since 1.8 |
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*/ |
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public class SplittableRandom { |
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public final class SplittableRandom { |
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|
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/* |
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* Implementation Overview. |
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* Methods nextLong, nextInt, and derivatives do not return the |
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* sequence (seed) values, but instead a hash-like bit-mix of |
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* their bits, producing more independently distributed sequences. |
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* For nextLong, the mix64 bit-mixing function computes the same |
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* value as the "64-bit finalizer" function in Austin Appleby's |
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* MurmurHash3 algorithm. See |
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* http://code.google.com/p/smhasher/wiki/MurmurHash3 , which |
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* comments: "The constants for the finalizers were generated by a |
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* simple simulated-annealing algorithm, and both avalanche all |
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* bits of 'h' to within 0.25% bias." The mix32 function is |
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* equivalent to (int)(mix64(seed) >>> 32), but faster because it |
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* omits a step that doesn't contribute to result. |
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* For nextLong, the mix64 function is based on David Stafford's |
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* (http://zimbry.blogspot.com/2011/09/better-bit-mixing-improving-on.html) |
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* "Mix13" variant of the "64-bit finalizer" function in Austin |
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* Appleby's MurmurHash3 algorithm (see |
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* http://code.google.com/p/smhasher/wiki/MurmurHash3). The mix32 |
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* function is based on Stafford's Mix04 mix function, but returns |
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* the upper 32 bits cast as int. |
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* |
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* The split operation uses the current generator to form the seed |
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* and gamma for another SplittableRandom. To conservatively |
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* avoid potential correlations between seed and value generation, |
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* gamma selection (method nextGamma) uses the "Mix13" constants |
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* for MurmurHash3 described by David Stafford |
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* (http://zimbry.blogspot.com/2011/09/better-bit-mixing-improving-on.html) |
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* To avoid potential weaknesses in bit-mixing transformations, we |
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* restrict gammas to odd values with at least 12 and no more than |
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* 52 bits set. Rather than rejecting candidates with too few or |
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* too many bits set, method nextGamma flips some bits (which has |
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* the effect of mapping at most 4 to any given gamma value). |
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* This reduces the effective set of 64bit odd gamma values by |
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* about 2<sup>14</sup>, a very tiny percentage, and serves as an |
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* gamma selection (method mixGamma) uses different |
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* (Murmurhash3's) mix constants. To avoid potential weaknesses |
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* in bit-mixing transformations, we restrict gammas to odd values |
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* with at least 24 0-1 or 1-0 bit transitions. Rather than |
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* rejecting candidates with too few or too many bits set, method |
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* mixGamma flips some bits (which has the effect of mapping at |
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* most 4 to any given gamma value). This reduces the effective |
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* set of 64bit odd gamma values by about 2%, and serves as an |
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* automated screening for sequence constant selection that is |
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* left as an empirical decision in some other hashing and crypto |
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* algorithms. |
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* avalanching. |
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* |
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* The default (no-argument) constructor, in essence, invokes |
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* split() for a common "seeder" SplittableRandom. Unlike other |
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* cases, this split must be performed in a thread-safe manner, so |
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* we use an AtomicLong to represent the seed rather than use an |
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* explicit SplittableRandom. To bootstrap the seeder, we start |
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* off using a seed based on current time and host. This serves as |
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* a slimmed-down (and insecure) variant of SecureRandom that also |
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* avoids stalls that may occur when using /dev/random. |
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* split() for a common "defaultGen" SplittableRandom. Unlike |
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* other cases, this split must be performed in a thread-safe |
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* manner, so we use an AtomicLong to represent the seed rather |
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* than use an explicit SplittableRandom. To bootstrap the |
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* defaultGen, we start off using a seed based on current time |
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* unless the java.util.secureRandomSeed property is set. This |
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* serves as a slimmed-down (and insecure) variant of SecureRandom |
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* that also avoids stalls that may occur when using /dev/random. |
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* |
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* It is a relatively simple matter to apply the basic design here |
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* to use 128 bit seeds. However, emulating 128bit arithmetic and |
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*/ |
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|
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/** |
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* The initial gamma value for (unsplit) SplittableRandoms. Must |
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* be odd with at least 12 and no more than 52 bits set. Currently |
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* set to the golden ratio scaled to 64bits. |
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* The golden ratio scaled to 64bits, used as the initial gamma |
159 |
> |
* value for (unsplit) SplittableRandoms. |
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*/ |
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< |
private static final long INITIAL_GAMMA = 0x9e3779b97f4a7c15L; |
161 |
> |
private static final long GOLDEN_GAMMA = 0x9e3779b97f4a7c15L; |
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|
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/** |
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* The least non-zero value returned by nextDouble(). This value |
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* is scaled by a random value of 53 bits to produce a result. |
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*/ |
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< |
private static final double DOUBLE_UNIT = 1.0 / (1L << 53); |
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> |
private static final double DOUBLE_UNIT = 0x1.0p-53; // 1.0 / (1L << 53); |
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/** |
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* The seed. Updated only via method nextSeed. |
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} |
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/** |
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* Computes MurmurHash3 64bit mix function. |
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> |
* Computes Stafford variant 13 of 64bit mix function. |
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*/ |
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private static long mix64(long z) { |
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< |
z = (z ^ (z >>> 33)) * 0xff51afd7ed558ccdL; |
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< |
z = (z ^ (z >>> 33)) * 0xc4ceb9fe1a85ec53L; |
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< |
return z ^ (z >>> 33); |
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> |
z = (z ^ (z >>> 30)) * 0xbf58476d1ce4e5b9L; |
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> |
z = (z ^ (z >>> 27)) * 0x94d049bb133111ebL; |
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> |
return z ^ (z >>> 31); |
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} |
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/** |
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< |
* Returns the 32 high bits of mix64(z) as int. |
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> |
* Returns the 32 high bits of Stafford variant 4 mix64 function as int. |
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*/ |
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private static int mix32(long z) { |
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z = (z ^ (z >>> 33)) * 0xff51afd7ed558ccdL; |
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< |
return (int)(((z ^ (z >>> 33)) * 0xc4ceb9fe1a85ec53L) >>> 32); |
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> |
z = (z ^ (z >>> 33)) * 0x62a9d9ed799705f5L; |
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> |
return (int)(((z ^ (z >>> 28)) * 0xcb24d0a5c88c35b3L) >>> 32); |
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} |
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/** |
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* Returns the gamma value to use for a new split instance. |
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*/ |
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< |
private static long nextGamma(long z) { |
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< |
z = (z ^ (z >>> 30)) * 0xbf58476d1ce4e5b9L; // Stafford "Mix13" |
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< |
z = (z ^ (z >>> 27)) * 0x94d049bb133111ebL; |
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< |
z = (z ^ (z >>> 31)) | 1L; // force to be odd |
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int n = Long.bitCount(z); // ensure enough 0 and 1 bits |
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return (n < 12 || n > 52) ? z ^ 0xaaaaaaaaaaaaaaaaL : z; |
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> |
private static long mixGamma(long z) { |
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> |
z = (z ^ (z >>> 33)) * 0xff51afd7ed558ccdL; // MurmurHash3 mix constants |
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> |
z = (z ^ (z >>> 33)) * 0xc4ceb9fe1a85ec53L; |
210 |
> |
z = (z ^ (z >>> 33)) | 1L; // force to be odd |
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> |
int n = Long.bitCount(z ^ (z >>> 1)); // ensure enough transitions |
212 |
> |
return (n < 24) ? z ^ 0xaaaaaaaaaaaaaaaaL : z; |
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} |
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/** |
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/** |
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* The seed generator for default constructors. |
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*/ |
225 |
< |
private static final AtomicLong seeder = |
225 |
< |
new AtomicLong(mix64((((long)hashedHostAddress()) << 32) ^ |
226 |
< |
System.currentTimeMillis()) ^ |
227 |
< |
mix64(System.nanoTime())); |
225 |
> |
private static final AtomicLong defaultGen = new AtomicLong(initialSeed()); |
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|
227 |
< |
/** |
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* Returns hash of local host IP address, if available; else 0. |
229 |
< |
*/ |
230 |
< |
private static int hashedHostAddress() { |
231 |
< |
try { |
232 |
< |
return InetAddress.getLocalHost().hashCode(); |
233 |
< |
} catch (Exception ex) { |
234 |
< |
return 0; |
227 |
> |
private static long initialSeed() { |
228 |
> |
java.security.PrivilegedAction<Boolean> action = |
229 |
> |
() -> Boolean.getBoolean("java.util.secureRandomSeed"); |
230 |
> |
if (java.security.AccessController.doPrivileged(action)) { |
231 |
> |
byte[] seedBytes = java.security.SecureRandom.getSeed(8); |
232 |
> |
long s = (long)seedBytes[0] & 0xffL; |
233 |
> |
for (int i = 1; i < 8; ++i) |
234 |
> |
s = (s << 8) | ((long)seedBytes[i] & 0xffL); |
235 |
> |
return s; |
236 |
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} |
237 |
+ |
return (mix64(System.currentTimeMillis()) ^ |
238 |
+ |
mix64(System.nanoTime())); |
239 |
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} |
240 |
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|
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// IllegalArgumentException messages |
242 |
< |
static final String BadBound = "bound must be positive"; |
243 |
< |
static final String BadRange = "bound must be greater than origin"; |
244 |
< |
static final String BadSize = "size must be non-negative"; |
242 |
> |
static final String BAD_BOUND = "bound must be positive"; |
243 |
> |
static final String BAD_RANGE = "bound must be greater than origin"; |
244 |
> |
static final String BAD_SIZE = "size must be non-negative"; |
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|
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/* |
247 |
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* Internal versions of nextX methods used by streams, as well as |
362 |
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* @param seed the initial seed |
363 |
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*/ |
364 |
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public SplittableRandom(long seed) { |
365 |
< |
this(seed, INITIAL_GAMMA); |
365 |
> |
this(seed, GOLDEN_GAMMA); |
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} |
367 |
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|
368 |
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/** |
371 |
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* of those of any other instances in the current program; and |
372 |
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* may, and typically does, vary across program invocations. |
373 |
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*/ |
374 |
< |
public SplittableRandom() { // emulate seeder.split() |
375 |
< |
this.gamma = nextGamma(this.seed = seeder.addAndGet(INITIAL_GAMMA)); |
374 |
> |
public SplittableRandom() { // emulate defaultGen.split() |
375 |
> |
long s = defaultGen.getAndAdd(2 * GOLDEN_GAMMA); |
376 |
> |
this.seed = mix64(s); |
377 |
> |
this.gamma = mixGamma(s + GOLDEN_GAMMA); |
378 |
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} |
379 |
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|
380 |
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/** |
392 |
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* @return the new SplittableRandom instance |
393 |
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*/ |
394 |
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public SplittableRandom split() { |
395 |
< |
long s = nextSeed(); |
393 |
< |
return new SplittableRandom(s, nextGamma(s)); |
395 |
> |
return new SplittableRandom(nextLong(), mixGamma(nextSeed())); |
396 |
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} |
397 |
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|
398 |
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/** |
408 |
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* Returns a pseudorandom {@code int} value between zero (inclusive) |
409 |
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* and the specified bound (exclusive). |
410 |
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* |
411 |
< |
* @param bound the bound on the random number to be returned. Must be |
410 |
< |
* positive. |
411 |
> |
* @param bound the upper bound (exclusive). Must be positive. |
412 |
|
* @return a pseudorandom {@code int} value between zero |
413 |
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* (inclusive) and the bound (exclusive) |
414 |
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* @throws IllegalArgumentException if {@code bound} is not positive |
415 |
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*/ |
416 |
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public int nextInt(int bound) { |
417 |
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if (bound <= 0) |
418 |
< |
throw new IllegalArgumentException(BadBound); |
418 |
> |
throw new IllegalArgumentException(BAD_BOUND); |
419 |
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// Specialize internalNextInt for origin 0 |
420 |
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int r = mix32(nextSeed()); |
421 |
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int m = bound - 1; |
443 |
|
*/ |
444 |
|
public int nextInt(int origin, int bound) { |
445 |
|
if (origin >= bound) |
446 |
< |
throw new IllegalArgumentException(BadRange); |
446 |
> |
throw new IllegalArgumentException(BAD_RANGE); |
447 |
|
return internalNextInt(origin, bound); |
448 |
|
} |
449 |
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|
460 |
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* Returns a pseudorandom {@code long} value between zero (inclusive) |
461 |
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* and the specified bound (exclusive). |
462 |
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* |
463 |
< |
* @param bound the bound on the random number to be returned. Must be |
463 |
< |
* positive. |
463 |
> |
* @param bound the upper bound (exclusive). Must be positive. |
464 |
|
* @return a pseudorandom {@code long} value between zero |
465 |
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* (inclusive) and the bound (exclusive) |
466 |
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* @throws IllegalArgumentException if {@code bound} is not positive |
467 |
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*/ |
468 |
|
public long nextLong(long bound) { |
469 |
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if (bound <= 0) |
470 |
< |
throw new IllegalArgumentException(BadBound); |
470 |
> |
throw new IllegalArgumentException(BAD_BOUND); |
471 |
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// Specialize internalNextLong for origin 0 |
472 |
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long r = mix64(nextSeed()); |
473 |
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long m = bound - 1; |
495 |
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*/ |
496 |
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public long nextLong(long origin, long bound) { |
497 |
|
if (origin >= bound) |
498 |
< |
throw new IllegalArgumentException(BadRange); |
498 |
> |
throw new IllegalArgumentException(BAD_RANGE); |
499 |
|
return internalNextLong(origin, bound); |
500 |
|
} |
501 |
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|
504 |
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* (inclusive) and one (exclusive). |
505 |
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* |
506 |
|
* @return a pseudorandom {@code double} value between zero |
507 |
< |
* (inclusive) and one (exclusive) |
507 |
> |
* (inclusive) and one (exclusive) |
508 |
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*/ |
509 |
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public double nextDouble() { |
510 |
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return (mix64(nextSeed()) >>> 11) * DOUBLE_UNIT; |
514 |
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* Returns a pseudorandom {@code double} value between 0.0 |
515 |
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* (inclusive) and the specified bound (exclusive). |
516 |
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* |
517 |
< |
* @param bound the bound on the random number to be returned. Must be |
518 |
< |
* positive. |
517 |
> |
* @param bound the upper bound (exclusive). Must be positive. |
518 |
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* @return a pseudorandom {@code double} value between zero |
519 |
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* (inclusive) and the bound (exclusive) |
520 |
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* @throws IllegalArgumentException if {@code bound} is not positive |
521 |
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*/ |
522 |
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public double nextDouble(double bound) { |
523 |
|
if (!(bound > 0.0)) |
524 |
< |
throw new IllegalArgumentException(BadBound); |
524 |
> |
throw new IllegalArgumentException(BAD_BOUND); |
525 |
|
double result = (mix64(nextSeed()) >>> 11) * DOUBLE_UNIT * bound; |
526 |
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return (result < bound) ? result : // correct for rounding |
527 |
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Double.longBitsToDouble(Double.doubleToLongBits(bound) - 1); |
532 |
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* origin (inclusive) and bound (exclusive). |
533 |
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* |
534 |
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* @param origin the least value returned |
535 |
< |
* @param bound the upper bound |
535 |
> |
* @param bound the upper bound (exclusive) |
536 |
|
* @return a pseudorandom {@code double} value between the origin |
537 |
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* (inclusive) and the bound (exclusive) |
538 |
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* @throws IllegalArgumentException if {@code origin} is greater than |
540 |
|
*/ |
541 |
|
public double nextDouble(double origin, double bound) { |
542 |
|
if (!(origin < bound)) |
543 |
< |
throw new IllegalArgumentException(BadRange); |
543 |
> |
throw new IllegalArgumentException(BAD_RANGE); |
544 |
|
return internalNextDouble(origin, bound); |
545 |
|
} |
546 |
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|
568 |
|
*/ |
569 |
|
public IntStream ints(long streamSize) { |
570 |
|
if (streamSize < 0L) |
571 |
< |
throw new IllegalArgumentException(BadSize); |
571 |
> |
throw new IllegalArgumentException(BAD_SIZE); |
572 |
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return StreamSupport.intStream |
573 |
|
(new RandomIntsSpliterator |
574 |
|
(this, 0L, streamSize, Integer.MAX_VALUE, 0), |
593 |
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|
594 |
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/** |
595 |
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* Returns a stream producing the given {@code streamSize} number |
596 |
< |
* of pseudorandom {@code int} values, each conforming to the |
597 |
< |
* given origin and bound. |
596 |
> |
* of pseudorandom {@code int} values from this generator and/or one split |
597 |
> |
* from it; each value conforms to the given origin (inclusive) and bound |
598 |
> |
* (exclusive). |
599 |
|
* |
600 |
|
* @param streamSize the number of values to generate |
601 |
< |
* @param randomNumberOrigin the origin of each random value |
602 |
< |
* @param randomNumberBound the bound of each random value |
601 |
> |
* @param randomNumberOrigin the origin (inclusive) of each random value |
602 |
> |
* @param randomNumberBound the bound (exclusive) of each random value |
603 |
|
* @return a stream of pseudorandom {@code int} values, |
604 |
< |
* each with the given origin and bound |
604 |
> |
* each with the given origin (inclusive) and bound (exclusive) |
605 |
|
* @throws IllegalArgumentException if {@code streamSize} is |
606 |
|
* less than zero, or {@code randomNumberOrigin} |
607 |
|
* is greater than or equal to {@code randomNumberBound} |
609 |
|
public IntStream ints(long streamSize, int randomNumberOrigin, |
610 |
|
int randomNumberBound) { |
611 |
|
if (streamSize < 0L) |
612 |
< |
throw new IllegalArgumentException(BadSize); |
612 |
> |
throw new IllegalArgumentException(BAD_SIZE); |
613 |
|
if (randomNumberOrigin >= randomNumberBound) |
614 |
< |
throw new IllegalArgumentException(BadRange); |
614 |
> |
throw new IllegalArgumentException(BAD_RANGE); |
615 |
|
return StreamSupport.intStream |
616 |
|
(new RandomIntsSpliterator |
617 |
|
(this, 0L, streamSize, randomNumberOrigin, randomNumberBound), |
620 |
|
|
621 |
|
/** |
622 |
|
* Returns an effectively unlimited stream of pseudorandom {@code |
623 |
< |
* int} values, each conforming to the given origin and bound. |
623 |
> |
* int} values from this generator and/or one split from it; each value |
624 |
> |
* conforms to the given origin (inclusive) and bound (exclusive). |
625 |
|
* |
626 |
|
* @implNote This method is implemented to be equivalent to {@code |
627 |
|
* ints(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound)}. |
628 |
|
* |
629 |
< |
* @param randomNumberOrigin the origin of each random value |
630 |
< |
* @param randomNumberBound the bound of each random value |
629 |
> |
* @param randomNumberOrigin the origin (inclusive) of each random value |
630 |
> |
* @param randomNumberBound the bound (exclusive) of each random value |
631 |
|
* @return a stream of pseudorandom {@code int} values, |
632 |
< |
* each with the given origin and bound |
632 |
> |
* each with the given origin (inclusive) and bound (exclusive) |
633 |
|
* @throws IllegalArgumentException if {@code randomNumberOrigin} |
634 |
|
* is greater than or equal to {@code randomNumberBound} |
635 |
|
*/ |
636 |
|
public IntStream ints(int randomNumberOrigin, int randomNumberBound) { |
637 |
|
if (randomNumberOrigin >= randomNumberBound) |
638 |
< |
throw new IllegalArgumentException(BadRange); |
638 |
> |
throw new IllegalArgumentException(BAD_RANGE); |
639 |
|
return StreamSupport.intStream |
640 |
|
(new RandomIntsSpliterator |
641 |
|
(this, 0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound), |
654 |
|
*/ |
655 |
|
public LongStream longs(long streamSize) { |
656 |
|
if (streamSize < 0L) |
657 |
< |
throw new IllegalArgumentException(BadSize); |
657 |
> |
throw new IllegalArgumentException(BAD_SIZE); |
658 |
|
return StreamSupport.longStream |
659 |
|
(new RandomLongsSpliterator |
660 |
|
(this, 0L, streamSize, Long.MAX_VALUE, 0L), |
679 |
|
|
680 |
|
/** |
681 |
|
* Returns a stream producing the given {@code streamSize} number of |
682 |
< |
* pseudorandom {@code long} values, each conforming to the |
683 |
< |
* given origin and bound. |
682 |
> |
* pseudorandom {@code long} values from this generator and/or one split |
683 |
> |
* from it; each value conforms to the given origin (inclusive) and bound |
684 |
> |
* (exclusive). |
685 |
|
* |
686 |
|
* @param streamSize the number of values to generate |
687 |
< |
* @param randomNumberOrigin the origin of each random value |
688 |
< |
* @param randomNumberBound the bound of each random value |
687 |
> |
* @param randomNumberOrigin the origin (inclusive) of each random value |
688 |
> |
* @param randomNumberBound the bound (exclusive) of each random value |
689 |
|
* @return a stream of pseudorandom {@code long} values, |
690 |
< |
* each with the given origin and bound |
690 |
> |
* each with the given origin (inclusive) and bound (exclusive) |
691 |
|
* @throws IllegalArgumentException if {@code streamSize} is |
692 |
|
* less than zero, or {@code randomNumberOrigin} |
693 |
|
* is greater than or equal to {@code randomNumberBound} |
695 |
|
public LongStream longs(long streamSize, long randomNumberOrigin, |
696 |
|
long randomNumberBound) { |
697 |
|
if (streamSize < 0L) |
698 |
< |
throw new IllegalArgumentException(BadSize); |
698 |
> |
throw new IllegalArgumentException(BAD_SIZE); |
699 |
|
if (randomNumberOrigin >= randomNumberBound) |
700 |
< |
throw new IllegalArgumentException(BadRange); |
700 |
> |
throw new IllegalArgumentException(BAD_RANGE); |
701 |
|
return StreamSupport.longStream |
702 |
|
(new RandomLongsSpliterator |
703 |
|
(this, 0L, streamSize, randomNumberOrigin, randomNumberBound), |
706 |
|
|
707 |
|
/** |
708 |
|
* Returns an effectively unlimited stream of pseudorandom {@code |
709 |
< |
* long} values, each conforming to the given origin and bound. |
709 |
> |
* long} values from this generator and/or one split from it; each value |
710 |
> |
* conforms to the given origin (inclusive) and bound (exclusive). |
711 |
|
* |
712 |
|
* @implNote This method is implemented to be equivalent to {@code |
713 |
|
* longs(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound)}. |
714 |
|
* |
715 |
< |
* @param randomNumberOrigin the origin of each random value |
716 |
< |
* @param randomNumberBound the bound of each random value |
715 |
> |
* @param randomNumberOrigin the origin (inclusive) of each random value |
716 |
> |
* @param randomNumberBound the bound (exclusive) of each random value |
717 |
|
* @return a stream of pseudorandom {@code long} values, |
718 |
< |
* each with the given origin and bound |
718 |
> |
* each with the given origin (inclusive) and bound (exclusive) |
719 |
|
* @throws IllegalArgumentException if {@code randomNumberOrigin} |
720 |
|
* is greater than or equal to {@code randomNumberBound} |
721 |
|
*/ |
722 |
|
public LongStream longs(long randomNumberOrigin, long randomNumberBound) { |
723 |
|
if (randomNumberOrigin >= randomNumberBound) |
724 |
< |
throw new IllegalArgumentException(BadRange); |
724 |
> |
throw new IllegalArgumentException(BAD_RANGE); |
725 |
|
return StreamSupport.longStream |
726 |
|
(new RandomLongsSpliterator |
727 |
|
(this, 0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound), |
730 |
|
|
731 |
|
/** |
732 |
|
* Returns a stream producing the given {@code streamSize} number of |
733 |
< |
* pseudorandom {@code double} values, each between zero |
734 |
< |
* (inclusive) and one (exclusive). |
733 |
> |
* pseudorandom {@code double} values from this generator and/or one split |
734 |
> |
* from it; each value is between zero (inclusive) and one (exclusive). |
735 |
|
* |
736 |
|
* @param streamSize the number of values to generate |
737 |
|
* @return a stream of {@code double} values |
740 |
|
*/ |
741 |
|
public DoubleStream doubles(long streamSize) { |
742 |
|
if (streamSize < 0L) |
743 |
< |
throw new IllegalArgumentException(BadSize); |
743 |
> |
throw new IllegalArgumentException(BAD_SIZE); |
744 |
|
return StreamSupport.doubleStream |
745 |
|
(new RandomDoublesSpliterator |
746 |
|
(this, 0L, streamSize, Double.MAX_VALUE, 0.0), |
749 |
|
|
750 |
|
/** |
751 |
|
* Returns an effectively unlimited stream of pseudorandom {@code |
752 |
< |
* double} values, each between zero (inclusive) and one |
753 |
< |
* (exclusive). |
752 |
> |
* double} values from this generator and/or one split from it; each value |
753 |
> |
* is between zero (inclusive) and one (exclusive). |
754 |
|
* |
755 |
|
* @implNote This method is implemented to be equivalent to {@code |
756 |
|
* doubles(Long.MAX_VALUE)}. |
766 |
|
|
767 |
|
/** |
768 |
|
* Returns a stream producing the given {@code streamSize} number of |
769 |
< |
* pseudorandom {@code double} values, each conforming to the |
770 |
< |
* given origin and bound. |
769 |
> |
* pseudorandom {@code double} values from this generator and/or one split |
770 |
> |
* from it; each value conforms to the given origin (inclusive) and bound |
771 |
> |
* (exclusive). |
772 |
|
* |
773 |
|
* @param streamSize the number of values to generate |
774 |
< |
* @param randomNumberOrigin the origin of each random value |
775 |
< |
* @param randomNumberBound the bound of each random value |
774 |
> |
* @param randomNumberOrigin the origin (inclusive) of each random value |
775 |
> |
* @param randomNumberBound the bound (exclusive) of each random value |
776 |
|
* @return a stream of pseudorandom {@code double} values, |
777 |
< |
* each with the given origin and bound |
777 |
> |
* each with the given origin (inclusive) and bound (exclusive) |
778 |
|
* @throws IllegalArgumentException if {@code streamSize} is |
779 |
< |
* less than zero |
779 |
> |
* less than zero |
780 |
|
* @throws IllegalArgumentException if {@code randomNumberOrigin} |
781 |
|
* is greater than or equal to {@code randomNumberBound} |
782 |
|
*/ |
783 |
|
public DoubleStream doubles(long streamSize, double randomNumberOrigin, |
784 |
|
double randomNumberBound) { |
785 |
|
if (streamSize < 0L) |
786 |
< |
throw new IllegalArgumentException(BadSize); |
786 |
> |
throw new IllegalArgumentException(BAD_SIZE); |
787 |
|
if (!(randomNumberOrigin < randomNumberBound)) |
788 |
< |
throw new IllegalArgumentException(BadRange); |
788 |
> |
throw new IllegalArgumentException(BAD_RANGE); |
789 |
|
return StreamSupport.doubleStream |
790 |
|
(new RandomDoublesSpliterator |
791 |
|
(this, 0L, streamSize, randomNumberOrigin, randomNumberBound), |
794 |
|
|
795 |
|
/** |
796 |
|
* Returns an effectively unlimited stream of pseudorandom {@code |
797 |
< |
* double} values, each conforming to the given origin and bound. |
797 |
> |
* double} values from this generator and/or one split from it; each value |
798 |
> |
* conforms to the given origin (inclusive) and bound (exclusive). |
799 |
|
* |
800 |
|
* @implNote This method is implemented to be equivalent to {@code |
801 |
|
* doubles(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound)}. |
802 |
|
* |
803 |
< |
* @param randomNumberOrigin the origin of each random value |
804 |
< |
* @param randomNumberBound the bound of each random value |
803 |
> |
* @param randomNumberOrigin the origin (inclusive) of each random value |
804 |
> |
* @param randomNumberBound the bound (exclusive) of each random value |
805 |
|
* @return a stream of pseudorandom {@code double} values, |
806 |
< |
* each with the given origin and bound |
806 |
> |
* each with the given origin (inclusive) and bound (exclusive) |
807 |
|
* @throws IllegalArgumentException if {@code randomNumberOrigin} |
808 |
|
* is greater than or equal to {@code randomNumberBound} |
809 |
|
*/ |
810 |
|
public DoubleStream doubles(double randomNumberOrigin, double randomNumberBound) { |
811 |
|
if (!(randomNumberOrigin < randomNumberBound)) |
812 |
< |
throw new IllegalArgumentException(BadRange); |
812 |
> |
throw new IllegalArgumentException(BAD_RANGE); |
813 |
|
return StreamSupport.doubleStream |
814 |
|
(new RandomDoublesSpliterator |
815 |
|
(this, 0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound), |
824 |
|
* approach. The long and double versions of this class are |
825 |
|
* identical except for types. |
826 |
|
*/ |
827 |
< |
static final class RandomIntsSpliterator implements Spliterator.OfInt { |
827 |
> |
private static final class RandomIntsSpliterator |
828 |
> |
implements Spliterator.OfInt { |
829 |
|
final SplittableRandom rng; |
830 |
|
long index; |
831 |
|
final long fence; |
880 |
|
/** |
881 |
|
* Spliterator for long streams. |
882 |
|
*/ |
883 |
< |
static final class RandomLongsSpliterator implements Spliterator.OfLong { |
883 |
> |
private static final class RandomLongsSpliterator |
884 |
> |
implements Spliterator.OfLong { |
885 |
|
final SplittableRandom rng; |
886 |
|
long index; |
887 |
|
final long fence; |
937 |
|
/** |
938 |
|
* Spliterator for double streams. |
939 |
|
*/ |
940 |
< |
static final class RandomDoublesSpliterator implements Spliterator.OfDouble { |
940 |
> |
private static final class RandomDoublesSpliterator |
941 |
> |
implements Spliterator.OfDouble { |
942 |
|
final SplittableRandom rng; |
943 |
|
long index; |
944 |
|
final long fence; |