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Comparing jsr166/src/main/java/util/SplittableRandom.java (file contents):
Revision 1.13 by dl, Thu Jul 25 13:19:09 2013 UTC vs.
Revision 1.23 by dl, Fri Sep 20 14:06:46 2013 UTC

#	Line 25 | Line 25
25
26		package java.util;
27
28	<	import java.security.SecureRandom;
28	>	import java.net.NetworkInterface;
29		import java.util.concurrent.atomic.AtomicLong;
30	–	import java.util.Spliterator;
30		import java.util.function.IntConsumer;
31		import java.util.function.LongConsumer;
32		import java.util.function.DoubleConsumer;
#	Line 39 | Line 38 | import java.util.stream.DoubleStream;
38		/**
39		* A generator of uniform pseudorandom values applicable for use in
40		* (among other contexts) isolated parallel computations that may
41	<	* generate subtasks. Class SplittableRandom supports methods for
41	>	* generate subtasks. Class {@code SplittableRandom} supports methods for
42		* producing pseudorandom numbers of type {@code int}, {@code long},
43		* and {@code double} with similar usages as for class
44		* {@link java.util.Random} but differs in the following ways:
#	Line 77 | Line 76 | import java.util.stream.DoubleStream;
76		*
77		* </ul>
78		*
79	+	* <p>Instances of {@code SplittableRandom} are not cryptographically
80	+	* secure.  Consider instead using {@link java.security.SecureRandom}
81	+	* in security-sensitive applications. Additionally,
82	+	* default-constructed instances do not use a cryptographically random
83	+	* seed unless the {@linkplain System#getProperty system property}
84	+	* {@code java.util.secureRandomSeed} is set to {@code true}.
85	+	*
86		* @author  Guy Steele
87		* @author  Doug Lea
88		* @since   1.8
89		*/
90	<	public class SplittableRandom {
85	<
86	<	/*
87	<	* File organization: First the non-public methods that constitute
88	<	* the main algorithm, then the main public methods, followed by
89	<	* some custom spliterator classes needed for stream methods.
90	<	*
91	<	* Credits: Primary algorithm and code by Guy Steele.  Stream
92	<	* support methods by Doug Lea.  Documentation jointly produced
93	<	* with additional help from Brian Goetz.
94	<	*/
90	>	public final class SplittableRandom {
91
92		/*
93		* Implementation Overview.
#	Line 99 | Line 95 | public class SplittableRandom {
95		* This algorithm was inspired by the "DotMix" algorithm by
96		* Leiserson, Schardl, and Sukha "Deterministic Parallel
97		* Random-Number Generation for Dynamic-Multithreading Platforms",
98	<	* PPoPP 2012, but improves and extends it in several ways.
98	>	* PPoPP 2012, as well as those in "Parallel random numbers: as
99	>	* easy as 1, 2, 3" by Salmon, Morae, Dror, and Shaw, SC 2011.  It
100	>	* differs mainly in simplifying and cheapening operations.
101	>	*
102	>	* The primary update step (method nextSeed()) is to add a
103	>	* constant ("gamma") to the current (64 bit) seed, forming a
104	>	* simple sequence.  The seed and the gamma values for any two
105	>	* SplittableRandom instances are highly likely to be different.
106	>	*
107	>	* Methods nextLong, nextInt, and derivatives do not return the
108	>	* sequence (seed) values, but instead a hash-like bit-mix of
109	>	* their bits, producing more independently distributed sequences.
110	>	* For nextLong, the mix64 function is based on David Stafford's
111	>	* (http://zimbry.blogspot.com/2011/09/better-bit-mixing-improving-on.html)
112	>	* "Mix13" variant of the "64-bit finalizer" function in Austin
113	>	* Appleby's MurmurHash3 algorithm See
114	>	* http://code.google.com/p/smhasher/wiki/MurmurHash3 . The mix32
115	>	* function is based on Stafford's Mix04 mix function, but returns
116	>	* the upper 32 bits cast as int.
117	>	*
118	>	* The split operation uses the current generator to form the seed
119	>	* and gamma for another SplittableRandom.  To conservatively
120	>	* avoid potential correlations between seed and value generation,
121	>	* gamma selection (method mixGamma) uses different
122	>	* (Murmurhash3's) mix constants.  To avoid potential weaknesses
123	>	* in bit-mixing transformations, we restrict gammas to odd values
124	>	* with at least 24 0-1 or 1-0 bit transitions.  Rather than
125	>	* rejecting candidates with too few or too many bits set, method
126	>	* mixGamma flips some bits (which has the effect of mapping at
127	>	* most 4 to any given gamma value).  This reduces the effective
128	>	* set of 64bit odd gamma values by about 2%, and serves as an
129	>	* automated screening for sequence constant selection that is
130	>	* left as an empirical decision in some other hashing and crypto
131	>	* algorithms.
132	>	*
133	>	* The resulting generator thus transforms a sequence in which
134	>	* (typically) many bits change on each step, with an inexpensive
135	>	* mixer with good (but less than cryptographically secure)
136	>	* avalanching.
137	>	*
138	>	* The default (no-argument) constructor, in essence, invokes
139	>	* split() for a common "defaultGen" SplittableRandom.  Unlike
140	>	* other cases, this split must be performed in a thread-safe
141	>	* manner, so we use an AtomicLong to represent the seed rather
142	>	* than use an explicit SplittableRandom. To bootstrap the
143	>	* defaultGen, we start off using a seed based on current time and
144	>	* network interface address unless the java.util.secureRandomSeed
145	>	* property is set. This serves as a slimmed-down (and insecure)
146	>	* variant of SecureRandom that also avoids stalls that may occur
147	>	* when using /dev/random.
148	>	*
149	>	* It is a relatively simple matter to apply the basic design here
150	>	* to use 128 bit seeds. However, emulating 128bit arithmetic and
151	>	* carrying around twice the state add more overhead than appears
152	>	* warranted for current usages.
153		*
154	<	* The primary update step (see method nextSeed()) is simply to
155	<	* add a constant ("gamma") to the current seed, modulo a prime
156	<	* ("George"). However, the nextLong and nextInt methods do not
107	<	* return this value, but instead the results of bit-mixing
108	<	* transformations that produce more uniformly distributed
109	<	* sequences.
110	<	*
111	<	* "George" is the otherwise nameless (because it cannot be
112	<	* represented) prime number 2^64+13. Using a prime number larger
113	<	* than can fit in a long ensures that all possible long values
114	<	* can occur, plus 13 others that just get skipped over when they
115	<	* are encountered; see method addGammaModGeorge. For this to
116	<	* work, initial gamma values must be at least 13.
117	<	*
118	<	* The mix64 bit-mixing function called by nextLong and other
119	<	* methods computes the same value as the "64-bit finalizer"
120	<	* function in Austin Appleby's MurmurHash3 algorithm.  See
121	<	* http://code.google.com/p/smhasher/wiki/MurmurHash3 , which
122	<	* comments: "The constants for the finalizers were generated by a
123	<	* simple simulated-annealing algorithm, and both avalanche all
124	<	* bits of 'h' to within 0.25% bias."
125	<	*
126	<	* The value of gamma differs for each instance across a series of
127	<	* splits, and is generated using an independent variant of the
128	<	* same algorithm, but operating across calls to split(), not
129	<	* calls to nextSeed(): Each instance carries the state of this
130	<	* generator as nextSplit. Gammas are treated as 57bit values,
131	<	* advancing by adding GAMMA_GAMMA mod GAMMA_PRIME, and bit-mixed
132	<	* with a 57-bit version of mix, using the "Mix01" multiplicative
133	<	* constants for MurmurHash3 described by David Stafford
134	<	* (http://zimbry.blogspot.com/2011/09/better-bit-mixing-improving-on.html).
135	<	* The value of GAMMA_GAMMA is arbitrary (except must be at least
136	<	* 13 and less than GAMMA_PRIME), but because it serves as the
137	<	* base of split sequences, should be subject to validation of
138	<	* consequent random number quality metrics.
139	<	*
140	<	* The mix32 function used for nextInt just consists of two of the
141	<	* five lines of mix64; avalanche testing shows that the 64-bit
142	<	* result has its top 32 bits avalanched well, though not the
143	<	* bottom 32 bits.  DieHarder tests show that it is adequate for
144	<	* generating one random int from the 64-bit result of nextSeed.
145	<	*
146	<	* Support for the default (no-argument) constructor relies on an
147	<	* AtomicLong (defaultSeedGenerator) to help perform the
148	<	* equivalent of a split of a statically constructed
149	<	* SplittableRandom. Unlike other cases, this split must be
150	<	* performed in a thread-safe manner. We use
151	<	* AtomicLong.compareAndSet as the (typically) most efficient
152	<	* mechanism. To bootstrap, we start off using a SecureRandom
153	<	* initial default seed, and update using a fixed
154	<	* DEFAULT_SEED_GAMMA. The default constructor uses GAMMA_GAMMA,
155	<	* not 0, for its splitSeed argument (addGammaModGeorge(0,
156	<	* GAMMA_GAMMA) == GAMMA_GAMMA) to reflect that each is split from
157	<	* this root generator, even though the root is not explicitly
158	<	* represented as a SplittableRandom.
159	<	*/
160	<
161	<	/**
162	<	* The prime modulus for gamma values.
163	<	*/
164	<	private static final long GAMMA_PRIME = (1L << 57) - 13L;
165	<
166	<	/**
167	<	* The value for producing new gamma values. Must be greater or
168	<	* equal to 13 and less than GAMMA_PRIME. Otherwise, the value is
169	<	* arbitrary subject to validation of the resulting statistical
170	<	* quality of splits.
171	<	*/
172	<	private static final long GAMMA_GAMMA = 0x00aae38294f712aabL;
173	<
174	<	/**
175	<	* The seed update value for default constructors.  Must be
176	<	* greater or equal to 13. Otherwise, the value is arbitrary
177	<	* subject to quality checks.
154	>	* File organization: First the non-public methods that constitute
155	>	* the main algorithm, then the main public methods, followed by
156	>	* some custom spliterator classes needed for stream methods.
157		*/
179	–	private static final long DEFAULT_SEED_GAMMA = 0x9e3779b97f4a7c15L;
158
159		/**
160	<	* The value 13 with 64bit sign bit set. Used in the signed
161	<	* comparison in addGammaModGeorge.
160	>	* The golden ratio scaled to 64bits, used as the initial gamma
161	>	* value for (unsplit) SplittableRandoms.
162		*/
163	<	private static final long BOTTOM13 = 0x800000000000000DL;
163	>	private static final long GOLDEN_GAMMA = 0x9e3779b97f4a7c15L;
164
165		/**
166		* The least non-zero value returned by nextDouble(). This value
167		* is scaled by a random value of 53 bits to produce a result.
168		*/
169	<	private static final double DOUBLE_UNIT = 1.0 / (1L << 53);
169	>	private static final double DOUBLE_ULP = 1.0 / (1L << 53);
170
171		/**
172	<	* The next seed for default constructors.
195	<	*/
196	<	private static final AtomicLong defaultSeedGenerator =
197	<	new AtomicLong(getInitialDefaultSeed());
198	<
199	<	/**
200	<	* The seed, updated only via method nextSeed.
172	>	* The seed. Updated only via method nextSeed.
173		*/
174		private long seed;
175
176		/**
177	<	* The constant value added to seed (mod George) on each update.
177	>	* The step value.
178		*/
179		private final long gamma;
180
181		/**
182	<	* The next seed to use for splits. Propagated using
211	<	* addGammaModGeorge across instances.
212	<	*/
213	<	private final long nextSplit;
214	<
215	<	/**
216	<	* Adds the given gamma value, g, to the given seed value s, mod
217	<	* George (2^64+13). We regard s and g as unsigned values
218	<	* (ranging from 0 to 2^64-1). We add g to s either once or twice
219	<	* (mod George) as necessary to produce an (unsigned) result less
220	<	* than 2^64.  We require that g must be at least 13. This
221	<	* guarantees that if (s+g) mod George >= 2^64 then (s+g+g) mod
222	<	* George < 2^64; thus we need only a conditional, not a loop,
223	<	* to be sure of getting a representable value.
224	<	*
225	<	* Because Java comparison operators are signed, we implement this
226	<	* by conceptually offsetting seed values downwards by 2^63, so
227	<	* 0..13 is represented as Long.MIN_VALUE..BOTTOM13.
228	<	*
229	<	* @param s a seed value, viewed as a signed long
230	<	* @param g a gamma value, 13 <= g (as unsigned)
182	>	* Internal constructor used by all others except default constructor.
183		*/
184	<	private static long addGammaModGeorge(long s, long g) {
185	<	long p = s + g;
186	<	return (p >= s) ? p : ((p >= BOTTOM13) ? p  : p + g) - 13L;
184	>	private SplittableRandom(long seed, long gamma) {
185	>	this.seed = seed;
186	>	this.gamma = gamma;
187		}
188
189		/**
190	<	* Returns a bit-mixed transformation of its argument.
239	<	* See above for explanation.
190	>	* Computes Stafford variant 13 of 64bit mix function.
191		*/
192		private static long mix64(long z) {
193	<	z ^= (z >>> 33);
194	<	z *= 0xff51afd7ed558ccdL;
195	<	z ^= (z >>> 33);
245	<	z *= 0xc4ceb9fe1a85ec53L;
246	<	z ^= (z >>> 33);
247	<	return z;
193	>	z *= 0xbf58476d1ce4e5b9L;
194	>	z = (z ^ (z >>> 32)) * 0x94d049bb133111ebL;
195	>	return z ^ (z >>> 32);
196		}
197
198		/**
199	<	* Returns a bit-mixed int transformation of its argument.
252	<	* See above for explanation.
199	>	* Returns the 32 high bits of Stafford variant 4 mix64 function as int.
200		*/
201		private static int mix32(long z) {
202	<	z ^= (z >>> 33);
203	<	z *= 0xc4ceb9fe1a85ec53L;
257	<	return (int)(z >>> 32);
258	<	}
259	<
260	<	/**
261	<	* Returns a 57-bit mixed transformation of its argument.  See
262	<	* above for explanation.
263	<	*/
264	<	private static long mix57(long z) {
265	<	z ^= (z >>> 33);
266	<	z *= 0x7fb5d329728ea185L;
267	<	z &= 0x01FFFFFFFFFFFFFFL;
268	<	z ^= (z >>> 33);
269	<	z *= 0x81dadef4bc2dd44dL;
270	<	z &= 0x01FFFFFFFFFFFFFFL;
271	<	z ^= (z >>> 33);
272	<	return z;
202	>	z *= 0x62a9d9ed799705f5L;
203	>	return (int)(((z ^ (z >>> 28)) * 0xcb24d0a5c88c35b3L) >>> 32);
204		}
205
206		/**
207	<	* Internal constructor used by all other constructors and by
277	<	* method split. Establishes the initial seed for this instance,
278	<	* and uses the given splitSeed to establish gamma, as well as the
279	<	* nextSplit to use by this instance. The loop to skip ineligible
280	<	* gammas very rarely iterates, and does so at most 13 times.
207	>	* Returns the gamma value to use for a new split instance.
208		*/
209	<	private SplittableRandom(long seed, long splitSeed) {
210	<	this.seed = seed;
211	<	long s = splitSeed, g;
212	<	do { // ensure gamma >= 13, considered as an unsigned integer
213	<	s += GAMMA_GAMMA;
214	<	if (s >= GAMMA_PRIME)
288	<	s -= GAMMA_PRIME;
289	<	g = mix57(s);
290	<	} while (g < 13L);
291	<	this.gamma = g;
292	<	this.nextSplit = s;
209	>	private static long mixGamma(long z) {
210	>	z *= 0xff51afd7ed558ccdL;                   // MurmurHash3 mix constants
211	>	z = (z ^ (z >>> 33)) * 0xc4ceb9fe1a85ec53L;
212	>	z = (z ^ (z >>> 33)) | 1L;                  // force to be odd
213	>	int n = Long.bitCount(z ^ (z >>> 1));       // ensure enough transitions
214	>	return (n < 24) ? z ^ 0xaaaaaaaaaaaaaaaaL : z;
215		}
216
217		/**
218	<	* Updates in-place and returns seed.
297	<	* See above for explanation.
218	>	* Adds gamma to seed.
219		*/
220		private long nextSeed() {
221	<	return seed = addGammaModGeorge(seed, gamma);
221	>	return seed += gamma;
222		}
223
224		/**
225	<	* Atomically updates and returns next seed for default constructor.
225	>	* The seed generator for default constructors.
226		*/
227	<	private static long nextDefaultSeed() {
307	<	long oldSeed, newSeed;
308	<	do {
309	<	oldSeed = defaultSeedGenerator.get();
310	<	newSeed = addGammaModGeorge(oldSeed, DEFAULT_SEED_GAMMA);
311	<	} while (!defaultSeedGenerator.compareAndSet(oldSeed, newSeed));
312	<	return mix64(newSeed);
313	<	}
227	>	private static final AtomicLong defaultGen = new AtomicLong(initialSeed());
228
229	<	/**
230	<	* Returns an initial default seed.
231	<	*/
232	<	private static long getInitialDefaultSeed() {
233	<	byte[] seedBytes = java.security.SecureRandom.getSeed(8);
234	<	long s = (long)(seedBytes[0]) & 0xffL;
235	<	for (int i = 1; i < 8; ++i)
236	<	s = (s << 8) | ((long)(seedBytes[i]) & 0xffL);
237	<	return s;
229	>	private static long initialSeed() {
230	>	String pp = java.security.AccessController.doPrivileged(
231	>	new sun.security.action.GetPropertyAction(
232	>	"java.util.secureRandomSeed"));
233	>	if (pp != null && pp.equalsIgnoreCase("true")) {
234	>	byte[] seedBytes = java.security.SecureRandom.getSeed(8);
235	>	long s = (long)(seedBytes[0]) & 0xffL;
236	>	for (int i = 1; i < 8; ++i)
237	>	s = (s << 8) | ((long)(seedBytes[i]) & 0xffL);
238	>	return s;
239	>	}
240	>	long h = 0L;
241	>	try {
242	>	Enumeration<NetworkInterface> ifcs =
243	>	NetworkInterface.getNetworkInterfaces();
244	>	boolean retry = false; // retry once if getHardwareAddress is null
245	>	while (ifcs.hasMoreElements()) {
246	>	NetworkInterface ifc = ifcs.nextElement();
247	>	if (!ifc.isVirtual()) { // skip fake addresses
248	>	byte[] bs = ifc.getHardwareAddress();
249	>	if (bs != null) {
250	>	int n = bs.length;
251	>	int m = Math.min(n >>> 1, 4);
252	>	for (int i = 0; i < m; ++i)
253	>	h = (h << 16) ^ (bs[i] << 8) ^ bs[n-1-i];
254	>	if (m < 4)
255	>	h = (h << 8) ^ bs[n-1-m];
256	>	h = mix64(h);
257	>	break;
258	>	}
259	>	else if (!retry)
260	>	retry = true;
261	>	else
262	>	break;
263	>	}
264	>	}
265	>	} catch (Exception ignore) {
266	>	}
267	>	return (h ^ mix64(System.currentTimeMillis()) ^
268	>	mix64(System.nanoTime()));
269		}
270
271	+	// IllegalArgumentException messages
272	+	static final String BadBound = "bound must be positive";
273	+	static final String BadRange = "bound must be greater than origin";
274	+	static final String BadSize  = "size must be non-negative";
275	+
276		/*
277		* Internal versions of nextX methods used by streams, as well as
278		* the public nextX(origin, bound) methods.  These exist mainly to
#	Line 423 | Line 373 | public class SplittableRandom {
373		* @return a pseudorandom value
374		*/
375		final double internalNextDouble(double origin, double bound) {
376	<	double r = (nextLong() >>> 11) * DOUBLE_UNIT;
376	>	double r = (nextLong() >>> 11) * DOUBLE_ULP;
377		if (origin < bound) {
378		r = r * (bound - origin) + origin;
379		if (r >= bound) // correct for rounding
#	Line 442 | Line 392 | public class SplittableRandom {
392		* @param seed the initial seed
393		*/
394		public SplittableRandom(long seed) {
395	<	this(seed, 0L);
395	>	this(seed, GOLDEN_GAMMA);
396		}
397
398		/**
#	Line 451 | Line 401 | public class SplittableRandom {
401		* of those of any other instances in the current program; and
402		* may, and typically does, vary across program invocations.
403		*/
404	<	public SplittableRandom() {
405	<	this(nextDefaultSeed(), GAMMA_GAMMA);
404	>	public SplittableRandom() { // emulate defaultGen.split()
405	>	long s = defaultGen.getAndAdd(2 * GOLDEN_GAMMA);
406	>	this.seed = mix64(s);
407	>	this.gamma = mixGamma(s + GOLDEN_GAMMA);
408		}
409
410		/**
#	Line 470 | Line 422 | public class SplittableRandom {
422		* @return the new SplittableRandom instance
423		*/
424		public SplittableRandom split() {
425	<	return new SplittableRandom(nextSeed(), nextSplit);
425	>	return new SplittableRandom(nextLong(), mixGamma(nextSeed()));
426		}
427
428		/**
#	Line 486 | Line 438 | public class SplittableRandom {
438		* Returns a pseudorandom {@code int} value between zero (inclusive)
439		* and the specified bound (exclusive).
440		*
441	<	* @param bound the bound on the random number to be returned.  Must be
490	<	*        positive.
441	>	* @param bound the upper bound (exclusive).  Must be positive.
442		* @return a pseudorandom {@code int} value between zero
443		*         (inclusive) and the bound (exclusive)
444	<	* @throws IllegalArgumentException if the bound is less than zero
444	>	* @throws IllegalArgumentException if {@code bound} is not positive
445		*/
446		public int nextInt(int bound) {
447		if (bound <= 0)
448	<	throw new IllegalArgumentException("bound must be positive");
448	>	throw new IllegalArgumentException(BadBound);
449		// Specialize internalNextInt for origin 0
450		int r = mix32(nextSeed());
451		int m = bound - 1;
#	Line 522 | Line 473 | public class SplittableRandom {
473		*/
474		public int nextInt(int origin, int bound) {
475		if (origin >= bound)
476	<	throw new IllegalArgumentException("bound must be greater than origin");
476	>	throw new IllegalArgumentException(BadRange);
477		return internalNextInt(origin, bound);
478		}
479
#	Line 539 | Line 490 | public class SplittableRandom {
490		* Returns a pseudorandom {@code long} value between zero (inclusive)
491		* and the specified bound (exclusive).
492		*
493	<	* @param bound the bound on the random number to be returned.  Must be
543	<	*        positive.
493	>	* @param bound the upper bound (exclusive).  Must be positive.
494		* @return a pseudorandom {@code long} value between zero
495		*         (inclusive) and the bound (exclusive)
496	<	* @throws IllegalArgumentException if {@code bound} is less than zero
496	>	* @throws IllegalArgumentException if {@code bound} is not positive
497		*/
498		public long nextLong(long bound) {
499		if (bound <= 0)
500	<	throw new IllegalArgumentException("bound must be positive");
500	>	throw new IllegalArgumentException(BadBound);
501		// Specialize internalNextLong for origin 0
502		long r = mix64(nextSeed());
503		long m = bound - 1;
#	Line 575 | Line 525 | public class SplittableRandom {
525		*/
526		public long nextLong(long origin, long bound) {
527		if (origin >= bound)
528	<	throw new IllegalArgumentException("bound must be greater than origin");
528	>	throw new IllegalArgumentException(BadRange);
529		return internalNextLong(origin, bound);
530		}
531
#	Line 584 | Line 534 | public class SplittableRandom {
534		* (inclusive) and one (exclusive).
535		*
536		* @return a pseudorandom {@code double} value between zero
537	<	* (inclusive) and one (exclusive)
537	>	*         (inclusive) and one (exclusive)
538		*/
539		public double nextDouble() {
540	<	return (mix64(nextSeed()) >>> 11) * DOUBLE_UNIT;
540	>	return (mix64(nextSeed()) >>> 11) * DOUBLE_ULP;
541		}
542
543		/**
544		* Returns a pseudorandom {@code double} value between 0.0
545		* (inclusive) and the specified bound (exclusive).
546		*
547	<	* @param bound the bound on the random number to be returned.  Must be
598	<	*        positive.
547	>	* @param bound the upper bound (exclusive).  Must be positive.
548		* @return a pseudorandom {@code double} value between zero
549		*         (inclusive) and the bound (exclusive)
550	<	* @throws IllegalArgumentException if {@code bound} is less than zero
550	>	* @throws IllegalArgumentException if {@code bound} is not positive
551		*/
552		public double nextDouble(double bound) {
553		if (!(bound > 0.0))
554	<	throw new IllegalArgumentException("bound must be positive");
555	<	double result = (mix64(nextSeed()) >>> 11) * DOUBLE_UNIT * bound;
554	>	throw new IllegalArgumentException(BadBound);
555	>	double result = (mix64(nextSeed()) >>> 11) * DOUBLE_ULP * bound;
556		return (result < bound) ?  result : // correct for rounding
557		Double.longBitsToDouble(Double.doubleToLongBits(bound) - 1);
558		}
#	Line 613 | Line 562 | public class SplittableRandom {
562		* origin (inclusive) and bound (exclusive).
563		*
564		* @param origin the least value returned
565	<	* @param bound the upper bound
565	>	* @param bound the upper bound (exclusive)
566		* @return a pseudorandom {@code double} value between the origin
567		*         (inclusive) and the bound (exclusive)
568		* @throws IllegalArgumentException if {@code origin} is greater than
#	Line 621 | Line 570 | public class SplittableRandom {
570		*/
571		public double nextDouble(double origin, double bound) {
572		if (!(origin < bound))
573	<	throw new IllegalArgumentException("bound must be greater than origin");
573	>	throw new IllegalArgumentException(BadRange);
574		return internalNextDouble(origin, bound);
575		}
576
#	Line 638 | Line 587 | public class SplittableRandom {
587		// maintenance purposes the small differences across forms.
588
589		/**
590	<	* Returns a stream producing the given {@code streamSize} number of
591	<	* pseudorandom {@code int} values.
590	>	* Returns a stream producing the given {@code streamSize} number
591	>	* of pseudorandom {@code int} values from this generator and/or
592	>	* one split from it.
593		*
594		* @param streamSize the number of values to generate
595		* @return a stream of pseudorandom {@code int} values
#	Line 648 | Line 598 | public class SplittableRandom {
598		*/
599		public IntStream ints(long streamSize) {
600		if (streamSize < 0L)
601	<	throw new IllegalArgumentException("negative Stream size");
601	>	throw new IllegalArgumentException(BadSize);
602		return StreamSupport.intStream
603		(new RandomIntsSpliterator
604		(this, 0L, streamSize, Integer.MAX_VALUE, 0),
#	Line 657 | Line 607 | public class SplittableRandom {
607
608		/**
609		* Returns an effectively unlimited stream of pseudorandom {@code int}
610	<	* values.
610	>	* values from this generator and/or one split from it.
611		*
612		* @implNote This method is implemented to be equivalent to {@code
613		* ints(Long.MAX_VALUE)}.
#	Line 672 | Line 622 | public class SplittableRandom {
622		}
623
624		/**
625	<	* Returns a stream producing the given {@code streamSize} number of
626	<	* pseudorandom {@code int} values, each conforming to the given
627	<	* origin and bound.
625	>	* Returns a stream producing the given {@code streamSize} number
626	>	* of pseudorandom {@code int} values from this generator and/or one split
627	>	* from it; each value conforms to the given origin (inclusive) and bound
628	>	* (exclusive).
629		*
630		* @param streamSize the number of values to generate
631	<	* @param randomNumberOrigin the origin of each random value
632	<	* @param randomNumberBound the bound of each random value
631	>	* @param randomNumberOrigin the origin (inclusive) of each random value
632	>	* @param randomNumberBound the bound (exclusive) of each random value
633		* @return a stream of pseudorandom {@code int} values,
634	<	*         each with the given origin and bound
634	>	*         each with the given origin (inclusive) and bound (exclusive)
635		* @throws IllegalArgumentException if {@code streamSize} is
636		*         less than zero, or {@code randomNumberOrigin}
637		*         is greater than or equal to {@code randomNumberBound}
#	Line 688 | Line 639 | public class SplittableRandom {
639		public IntStream ints(long streamSize, int randomNumberOrigin,
640		int randomNumberBound) {
641		if (streamSize < 0L)
642	<	throw new IllegalArgumentException("negative Stream size");
642	>	throw new IllegalArgumentException(BadSize);
643		if (randomNumberOrigin >= randomNumberBound)
644	<	throw new IllegalArgumentException("bound must be greater than origin");
644	>	throw new IllegalArgumentException(BadRange);
645		return StreamSupport.intStream
646		(new RandomIntsSpliterator
647		(this, 0L, streamSize, randomNumberOrigin, randomNumberBound),
#	Line 699 | Line 650 | public class SplittableRandom {
650
651		/**
652		* Returns an effectively unlimited stream of pseudorandom {@code
653	<	* int} values, each conforming to the given origin and bound.
653	>	* int} values from this generator and/or one split from it; each value
654	>	* conforms to the given origin (inclusive) and bound (exclusive).
655		*
656		* @implNote This method is implemented to be equivalent to {@code
657		* ints(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound)}.
658		*
659	<	* @param randomNumberOrigin the origin of each random value
660	<	* @param randomNumberBound the bound of each random value
659	>	* @param randomNumberOrigin the origin (inclusive) of each random value
660	>	* @param randomNumberBound the bound (exclusive) of each random value
661		* @return a stream of pseudorandom {@code int} values,
662	<	*         each with the given origin and bound
662	>	*         each with the given origin (inclusive) and bound (exclusive)
663		* @throws IllegalArgumentException if {@code randomNumberOrigin}
664		*         is greater than or equal to {@code randomNumberBound}
665		*/
666		public IntStream ints(int randomNumberOrigin, int randomNumberBound) {
667		if (randomNumberOrigin >= randomNumberBound)
668	<	throw new IllegalArgumentException("bound must be greater than origin");
668	>	throw new IllegalArgumentException(BadRange);
669		return StreamSupport.intStream
670		(new RandomIntsSpliterator
671		(this, 0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound),
#	Line 721 | Line 673 | public class SplittableRandom {
673		}
674
675		/**
676	<	* Returns a stream producing the given {@code streamSize} number of
677	<	* pseudorandom {@code long} values.
676	>	* Returns a stream producing the given {@code streamSize} number
677	>	* of pseudorandom {@code long} values from this generator and/or
678	>	* one split from it.
679		*
680		* @param streamSize the number of values to generate
681		* @return a stream of pseudorandom {@code long} values
#	Line 731 | Line 684 | public class SplittableRandom {
684		*/
685		public LongStream longs(long streamSize) {
686		if (streamSize < 0L)
687	<	throw new IllegalArgumentException("negative Stream size");
687	>	throw new IllegalArgumentException(BadSize);
688		return StreamSupport.longStream
689		(new RandomLongsSpliterator
690		(this, 0L, streamSize, Long.MAX_VALUE, 0L),
#	Line 739 | Line 692 | public class SplittableRandom {
692		}
693
694		/**
695	<	* Returns an effectively unlimited stream of pseudorandom {@code long}
696	<	* values.
695	>	* Returns an effectively unlimited stream of pseudorandom {@code
696	>	* long} values from this generator and/or one split from it.
697		*
698		* @implNote This method is implemented to be equivalent to {@code
699		* longs(Long.MAX_VALUE)}.
#	Line 756 | Line 709 | public class SplittableRandom {
709
710		/**
711		* Returns a stream producing the given {@code streamSize} number of
712	<	* pseudorandom {@code long} values, each conforming to the
713	<	* given origin and bound.
712	>	* pseudorandom {@code long} values from this generator and/or one split
713	>	* from it; each value conforms to the given origin (inclusive) and bound
714	>	* (exclusive).
715		*
716		* @param streamSize the number of values to generate
717	<	* @param randomNumberOrigin the origin of each random value
718	<	* @param randomNumberBound the bound of each random value
717	>	* @param randomNumberOrigin the origin (inclusive) of each random value
718	>	* @param randomNumberBound the bound (exclusive) of each random value
719		* @return a stream of pseudorandom {@code long} values,
720	<	*         each with the given origin and bound
720	>	*         each with the given origin (inclusive) and bound (exclusive)
721		* @throws IllegalArgumentException if {@code streamSize} is
722		*         less than zero, or {@code randomNumberOrigin}
723		*         is greater than or equal to {@code randomNumberBound}
#	Line 771 | Line 725 | public class SplittableRandom {
725		public LongStream longs(long streamSize, long randomNumberOrigin,
726		long randomNumberBound) {
727		if (streamSize < 0L)
728	<	throw new IllegalArgumentException("negative Stream size");
728	>	throw new IllegalArgumentException(BadSize);
729		if (randomNumberOrigin >= randomNumberBound)
730	<	throw new IllegalArgumentException("bound must be greater than origin");
730	>	throw new IllegalArgumentException(BadRange);
731		return StreamSupport.longStream
732		(new RandomLongsSpliterator
733		(this, 0L, streamSize, randomNumberOrigin, randomNumberBound),
#	Line 782 | Line 736 | public class SplittableRandom {
736
737		/**
738		* Returns an effectively unlimited stream of pseudorandom {@code
739	<	* long} values, each conforming to the given origin and bound.
739	>	* long} values from this generator and/or one split from it; each value
740	>	* conforms to the given origin (inclusive) and bound (exclusive).
741		*
742		* @implNote This method is implemented to be equivalent to {@code
743		* longs(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound)}.
744		*
745	<	* @param randomNumberOrigin the origin of each random value
746	<	* @param randomNumberBound the bound of each random value
745	>	* @param randomNumberOrigin the origin (inclusive) of each random value
746	>	* @param randomNumberBound the bound (exclusive) of each random value
747		* @return a stream of pseudorandom {@code long} values,
748	<	*         each with the given origin and bound
748	>	*         each with the given origin (inclusive) and bound (exclusive)
749		* @throws IllegalArgumentException if {@code randomNumberOrigin}
750		*         is greater than or equal to {@code randomNumberBound}
751		*/
752		public LongStream longs(long randomNumberOrigin, long randomNumberBound) {
753		if (randomNumberOrigin >= randomNumberBound)
754	<	throw new IllegalArgumentException("bound must be greater than origin");
754	>	throw new IllegalArgumentException(BadRange);
755		return StreamSupport.longStream
756		(new RandomLongsSpliterator
757		(this, 0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound),
#	Line 805 | Line 760 | public class SplittableRandom {
760
761		/**
762		* Returns a stream producing the given {@code streamSize} number of
763	<	* pseudorandom {@code double} values, each between zero
764	<	* (inclusive) and one (exclusive).
763	>	* pseudorandom {@code double} values from this generator and/or one split
764	>	* from it; each value is between zero (inclusive) and one (exclusive).
765		*
766		* @param streamSize the number of values to generate
767		* @return a stream of {@code double} values
#	Line 815 | Line 770 | public class SplittableRandom {
770		*/
771		public DoubleStream doubles(long streamSize) {
772		if (streamSize < 0L)
773	<	throw new IllegalArgumentException("negative Stream size");
773	>	throw new IllegalArgumentException(BadSize);
774		return StreamSupport.doubleStream
775		(new RandomDoublesSpliterator
776		(this, 0L, streamSize, Double.MAX_VALUE, 0.0),
#	Line 824 | Line 779 | public class SplittableRandom {
779
780		/**
781		* Returns an effectively unlimited stream of pseudorandom {@code
782	<	* double} values, each between zero (inclusive) and one
783	<	* (exclusive).
782	>	* double} values from this generator and/or one split from it; each value
783	>	* is between zero (inclusive) and one (exclusive).
784		*
785		* @implNote This method is implemented to be equivalent to {@code
786		* doubles(Long.MAX_VALUE)}.
#	Line 841 | Line 796 | public class SplittableRandom {
796
797		/**
798		* Returns a stream producing the given {@code streamSize} number of
799	<	* pseudorandom {@code double} values, each conforming to the
800	<	* given origin and bound.
799	>	* pseudorandom {@code double} values from this generator and/or one split
800	>	* from it; each value conforms to the given origin (inclusive) and bound
801	>	* (exclusive).
802		*
803		* @param streamSize the number of values to generate
804	<	* @param randomNumberOrigin the origin of each random value
805	<	* @param randomNumberBound the bound of each random value
804	>	* @param randomNumberOrigin the origin (inclusive) of each random value
805	>	* @param randomNumberBound the bound (exclusive) of each random value
806		* @return a stream of pseudorandom {@code double} values,
807	<	* each with the given origin and bound
807	>	*         each with the given origin (inclusive) and bound (exclusive)
808		* @throws IllegalArgumentException if {@code streamSize} is
809	<	* less than zero
809	>	*         less than zero
810		* @throws IllegalArgumentException if {@code randomNumberOrigin}
811		*         is greater than or equal to {@code randomNumberBound}
812		*/
813		public DoubleStream doubles(long streamSize, double randomNumberOrigin,
814		double randomNumberBound) {
815		if (streamSize < 0L)
816	<	throw new IllegalArgumentException("negative Stream size");
816	>	throw new IllegalArgumentException(BadSize);
817		if (!(randomNumberOrigin < randomNumberBound))
818	<	throw new IllegalArgumentException("bound must be greater than origin");
818	>	throw new IllegalArgumentException(BadRange);
819		return StreamSupport.doubleStream
820		(new RandomDoublesSpliterator
821		(this, 0L, streamSize, randomNumberOrigin, randomNumberBound),
#	Line 868 | Line 824 | public class SplittableRandom {
824
825		/**
826		* Returns an effectively unlimited stream of pseudorandom {@code
827	<	* double} values, each conforming to the given origin and bound.
827	>	* double} values from this generator and/or one split from it; each value
828	>	* conforms to the given origin (inclusive) and bound (exclusive).
829		*
830		* @implNote This method is implemented to be equivalent to {@code
831		* doubles(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound)}.
832		*
833	<	* @param randomNumberOrigin the origin of each random value
834	<	* @param randomNumberBound the bound of each random value
833	>	* @param randomNumberOrigin the origin (inclusive) of each random value
834	>	* @param randomNumberBound the bound (exclusive) of each random value
835		* @return a stream of pseudorandom {@code double} values,
836	<	* each with the given origin and bound
836	>	*         each with the given origin (inclusive) and bound (exclusive)
837		* @throws IllegalArgumentException if {@code randomNumberOrigin}
838		*         is greater than or equal to {@code randomNumberBound}
839		*/
840		public DoubleStream doubles(double randomNumberOrigin, double randomNumberBound) {
841		if (!(randomNumberOrigin < randomNumberBound))
842	<	throw new IllegalArgumentException("bound must be greater than origin");
842	>	throw new IllegalArgumentException(BadRange);
843		return StreamSupport.doubleStream
844		(new RandomDoublesSpliterator
845		(this, 0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound),
#	Line 940 | Line 897 | public class SplittableRandom {
897		long i = index, f = fence;
898		if (i < f) {
899		index = f;
900	+	SplittableRandom r = rng;
901		int o = origin, b = bound;
902		do {
903	<	consumer.accept(rng.internalNextInt(o, b));
903	>	consumer.accept(r.internalNextInt(o, b));
904		} while (++i < f);
905		}
906		}
#	Line 994 | Line 952 | public class SplittableRandom {
952		long i = index, f = fence;
953		if (i < f) {
954		index = f;
955	+	SplittableRandom r = rng;
956		long o = origin, b = bound;
957		do {
958	<	consumer.accept(rng.internalNextLong(o, b));
958	>	consumer.accept(r.internalNextLong(o, b));
959		} while (++i < f);
960		}
961		}
#	Line 1049 | Line 1008 | public class SplittableRandom {
1008		long i = index, f = fence;
1009		if (i < f) {
1010		index = f;
1011	+	SplittableRandom r = rng;
1012		double o = origin, b = bound;
1013		do {
1014	<	consumer.accept(rng.internalNextDouble(o, b));
1014	>	consumer.accept(r.internalNextDouble(o, b));
1015		} while (++i < f);
1016		}
1017		}

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