25 |
|
|
26 |
|
package java.util; |
27 |
|
|
28 |
– |
import java.net.NetworkInterface; |
28 |
|
import java.util.concurrent.atomic.AtomicLong; |
29 |
+ |
import java.util.function.DoubleConsumer; |
30 |
|
import java.util.function.IntConsumer; |
31 |
|
import java.util.function.LongConsumer; |
32 |
< |
import java.util.function.DoubleConsumer; |
33 |
< |
import java.util.stream.StreamSupport; |
32 |
> |
import java.util.stream.DoubleStream; |
33 |
|
import java.util.stream.IntStream; |
34 |
|
import java.util.stream.LongStream; |
35 |
< |
import java.util.stream.DoubleStream; |
35 |
> |
import java.util.stream.StreamSupport; |
36 |
|
|
37 |
|
/** |
38 |
|
* A generator of uniform pseudorandom values applicable for use in |
52 |
|
* types and ranges, but similar properties are expected to hold, at |
53 |
|
* least approximately, for others as well. The <em>period</em> |
54 |
|
* (length of any series of generated values before it repeats) is at |
55 |
< |
* least 2<sup>64</sup>. </li> |
55 |
> |
* least 2<sup>64</sup>. |
56 |
|
* |
57 |
< |
* <li> Method {@link #split} constructs and returns a new |
57 |
> |
* <li>Method {@link #split} constructs and returns a new |
58 |
|
* SplittableRandom instance that shares no mutable state with the |
59 |
|
* current instance. However, with very high probability, the |
60 |
|
* values collectively generated by the two objects have the same |
61 |
|
* statistical properties as if the same quantity of values were |
62 |
|
* generated by a single thread using a single {@code |
63 |
< |
* SplittableRandom} object. </li> |
63 |
> |
* SplittableRandom} object. |
64 |
|
* |
65 |
|
* <li>Instances of SplittableRandom are <em>not</em> thread-safe. |
66 |
|
* They are designed to be split, not shared, across threads. For |
71 |
|
* |
72 |
|
* <li>This class provides additional methods for generating random |
73 |
|
* streams, that employ the above techniques when used in {@code |
74 |
< |
* stream.parallel()} mode.</li> |
74 |
> |
* stream.parallel()} mode. |
75 |
|
* |
76 |
|
* </ul> |
77 |
|
* |
139 |
|
* other cases, this split must be performed in a thread-safe |
140 |
|
* manner, so we use an AtomicLong to represent the seed rather |
141 |
|
* than use an explicit SplittableRandom. To bootstrap the |
142 |
< |
* defaultGen, we start off using a seed based on current time and |
143 |
< |
* network interface address unless the java.util.secureRandomSeed |
144 |
< |
* property is set. This serves as a slimmed-down (and insecure) |
145 |
< |
* variant of SecureRandom that also avoids stalls that may occur |
147 |
< |
* when using /dev/random. |
142 |
> |
* defaultGen, we start off using a seed based on current time |
143 |
> |
* unless the java.util.secureRandomSeed property is set. This |
144 |
> |
* serves as a slimmed-down (and insecure) variant of SecureRandom |
145 |
> |
* that also avoids stalls that may occur when using /dev/random. |
146 |
|
* |
147 |
|
* It is a relatively simple matter to apply the basic design here |
148 |
|
* to use 128 bit seeds. However, emulating 128bit arithmetic and |
225 |
|
private static final AtomicLong defaultGen = new AtomicLong(initialSeed()); |
226 |
|
|
227 |
|
private static long initialSeed() { |
228 |
< |
String pp = java.security.AccessController.doPrivileged( |
229 |
< |
new sun.security.action.GetPropertyAction( |
230 |
< |
"java.util.secureRandomSeed")); |
233 |
< |
if (pp != null && pp.equalsIgnoreCase("true")) { |
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; |
232 |
> |
long s = (long)seedBytes[0] & 0xffL; |
233 |
|
for (int i = 1; i < 8; ++i) |
234 |
< |
s = (s << 8) | ((long)(seedBytes[i]) & 0xffL); |
234 |
> |
s = (s << 8) | ((long)seedBytes[i] & 0xffL); |
235 |
|
return s; |
236 |
|
} |
237 |
< |
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()) ^ |
237 |
> |
return (mix64(System.currentTimeMillis()) ^ |
238 |
|
mix64(System.nanoTime())); |
239 |
|
} |
240 |
|
|
241 |
|
// 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"; |
245 |
|
|
246 |
|
/* |
247 |
|
* Internal versions of nextX methods used by streams, as well as |
415 |
|
*/ |
416 |
|
public int nextInt(int bound) { |
417 |
|
if (bound <= 0) |
418 |
< |
throw new IllegalArgumentException(BadBound); |
418 |
> |
throw new IllegalArgumentException(BAD_BOUND); |
419 |
|
// Specialize internalNextInt for origin 0 |
420 |
|
int r = mix32(nextSeed()); |
421 |
|
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 |
|
|
467 |
|
*/ |
468 |
|
public long nextLong(long bound) { |
469 |
|
if (bound <= 0) |
470 |
< |
throw new IllegalArgumentException(BadBound); |
470 |
> |
throw new IllegalArgumentException(BAD_BOUND); |
471 |
|
// Specialize internalNextLong for origin 0 |
472 |
|
long r = mix64(nextSeed()); |
473 |
|
long m = bound - 1; |
495 |
|
*/ |
496 |
|
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 |
|
|
521 |
|
*/ |
522 |
|
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 |
|
return (result < bound) ? result : // correct for rounding |
527 |
|
Double.longBitsToDouble(Double.doubleToLongBits(bound) - 1); |
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 |
|
|
568 |
|
*/ |
569 |
|
public IntStream ints(long streamSize) { |
570 |
|
if (streamSize < 0L) |
571 |
< |
throw new IllegalArgumentException(BadSize); |
571 |
> |
throw new IllegalArgumentException(BAD_SIZE); |
572 |
|
return StreamSupport.intStream |
573 |
|
(new RandomIntsSpliterator |
574 |
|
(this, 0L, streamSize, Integer.MAX_VALUE, 0), |
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), |
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), |
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), |
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), |
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), |
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), |
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; |