/*
 
* Copyright (c) 1995, 2013, Oracle and/or its affiliates. All rights reserved.
 
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 
*
 
* This code is free software; you can redistribute it and/or modify it
 
* under the terms of the GNU General Public License version 2 only, as
 
* published by the Free Software Foundation.
  
Oracle designates this
 
* particular file as subject to the "Classpath" exception as provided
 
* by Oracle in the LICENSE file that accompanied this code.
 
*
 
* This code is distributed in the hope that it will be useful, but WITHOUT
 
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 
* FITNESS FOR A PARTICULAR PURPOSE.
  
See the GNU General Public License
 
* version 2 for more details (a copy is included in the LICENSE file that
 
* accompanied this code).
 
*
 
* You should have received a copy of the GNU General Public License version
 
* 2 along with this work; if not, write to the Free Software Foundation,
 
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 
*
 
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 
* or visit www.oracle.com if you need additional information or have any
 
* questions.
 
*/

package java.util;
import java.io.*;
import java.util.concurrent.atomic.AtomicLong;
import java.util.function.DoubleConsumer;
import java.util.function.IntConsumer;
import java.util.function.LongConsumer;
import java.util.stream.DoubleStream;
import java.util.stream.IntStream;
import java.util.stream.LongStream;
import java.util.stream.StreamSupport;

import sun.misc.Unsafe;

/**
 
* An instance of this class is used to generate a stream of
 
* pseudorandom numbers. The class uses a 48-bit seed, which is
 
* modified using a linear congruential formula. (See Donald Knuth,
 
* <i>The Art of Computer Programming, Volume 2</i>, Section 3.2.1.)
 
* <p>
 
* If two instances of {@code Random} are created with the same
 
* seed, and the same sequence of method calls is made for each, they
 
* will generate and return identical sequences of numbers. In order to
 
* guarantee this property, particular algorithms are specified for the
 
* class {@code Random}. Java implementations must use all the algorithms
 
* shown here for the class {@code Random}, for the sake of absolute
 
* portability of Java code. However, subclasses of class {@code Random}
 
* are permitted to use other algorithms, so long as they adhere to the
 
* general contracts for all the methods.
 
* <p>
 
* The algorithms implemented by class {@code Random} use a
 
* {@code protected} utility method that on each invocation can supply
 
* up to 32 pseudorandomly generated bits.
 
* <p>
 
* Many applications will find the method {@link Math#random} simpler to use.
 
*
 
* <p>Instances of {@code java.util.Random} are threadsafe.
 
* However, the concurrent use of the same {@code java.util.Random}
 
* instance across threads may encounter contention and consequent
 
* poor performance. Consider instead using
 
*
 
in multithreaded
 
* designs.
 
*
 
* <p>Instances of {@code java.util.Random} are not cryptographically
 
* secure.
  
Consider instead using
 
to
 
* get a cryptographically secure pseudo-random number generator for use
 
* by security-sensitive applications.
 
*
 
* @author
  
Frank Yellin
 
* @since
   
1.0
 
*/

public
class
Random implements java.io.Serializable {
    
/** use serialVersionUID from JDK 1.1 for interoperability */
    
static final long serialVersionUID = 3905348978240129619L;

    
/**
     
* The internal state associated with this pseudorandom number generator.
     
* (The specs for the methods in this class describe the ongoing
     
* computation of this value.)
     
*/

    
private final AtomicLong seed;

    
private static final long multiplier = 0x5DEECE66DL;
    
private static final long addend = 0xBL;
    
private static final long mask = (1L << 48) - 1;

    
private static final double DOUBLE_UNIT = 0x1.0p-53; // 1.0 / (1L << 53)

    
// IllegalArgumentException messages
    
static final String BadBound = "bound must be positive";
    
static final String BadRange = "bound must be greater than origin";
    
static final String BadSize
  
= "size must be non-negative";

    
/**
     
* Creates a new random number generator. This constructor sets
     
* the seed of the random number generator to a value very likely
     
* to be distinct from any other invocation of this constructor.
     
*/

    
public Random() {
        
this(seedUniquifier() ^ System.nanoTime());
    
}

    
private static long seedUniquifier() {
        
// L'Ecuyer, "Tables of Linear Congruential Generators of
        
// Different Sizes and Good Lattice Structure", 1999
        
for (;;) {
            
long current = seedUniquifier.get();
            
long next = current * 181783497276652981L;
            
if (seedUniquifier.compareAndSet(current, next))
                
return next;
        
}
    
}

    
private static final AtomicLong seedUniquifier
        
= new AtomicLong(8682522807148012L);

    
/**
     
* Creates a new random number generator using a single {@code long} seed.
     
* The seed is the initial value of the internal state of the pseudorandom
     
* number generator which is maintained by method {@link #next}.
     
*
     
* <p>The invocation {@code new Random(seed)} is equivalent to:
     
*
  
<pre> {@code
     
* Random rnd = new Random();
     
* rnd.setSeed(seed);}</pre>
     
*
     
* @param seed the initial seed
     
* @see
   
#setSeed(long)
     
*/

    
public Random(long seed) {
        
if (getClass() == Random.class)
            
this.seed = new AtomicLong(initialScramble(seed));
        
else {
            
// subclass might have overriden setSeed
            
this.seed = new AtomicLong();
            
setSeed(seed);
        
}
    
}

    
private static long initialScramble(long seed) {
        
return (seed ^ multiplier) & mask;
    
}

    
/**
     
* Sets the seed of this random number generator using a single
     
* {@code long} seed. The general contract of {@code setSeed} is
     
* that it alters the state of this random number generator object
     
* so as to be in exactly the same state as if it had just been
     
* created with the argument {@code seed} as a seed. The method
     
* {@code setSeed} is implemented by class {@code Random} by
     
* atomically updating the seed to
     
*
  
<pre>{@code (seed ^ 0x5DEECE66DL) & ((1L << 48) - 1)}</pre>
     
* and clearing the {@code haveNextNextGaussian} flag used by {@link
     
* #nextGaussian}.
     
*
     
* <p>The implementation of {@code setSeed} by class {@code Random}
     
* happens to use only 48 bits of the given seed. In general, however,
     
* an overriding method may use all 64 bits of the {@code long}
     
* argument as a seed value.
     
*
     
* @param seed the initial seed
     
*/

    
synchronized public void setSeed(long seed) {
        
this.seed.set(initialScramble(seed));
        
haveNextNextGaussian = false;
    
}

    
/**
     
* Generates the next pseudorandom number. Subclasses should
     
* override this, as this is used by all other methods.
     
*
     
* <p>The general contract of {@code next} is that it returns an
     
* {@code int} value and if the argument {@code bits} is between
     
* {@code 1} and {@code 32} (inclusive), then that many low-order
     
* bits of the returned value will be (approximately) independently
     
* chosen bit values, each of which is (approximately) equally
     
* likely to be {@code 0} or {@code 1}. The method {@code next} is
     
* implemented by class {@code Random} by atomically updating the seed to
     
*
  
<pre>{@code (seed * 0x5DEECE66DL + 0xBL) & ((1L << 48) - 1)}</pre>
     
* and returning
     
*
  
<pre>{@code (int)(seed >>> (48 - bits))}.</pre>
     
*
     
* This is a linear congruential pseudorandom number generator, as
     
* defined by D. H. Lehmer and described by Donald E. Knuth in
     
* <i>The Art of Computer Programming,</i> Volume 3:
     
* <i>Seminumerical Algorithms</i>, section 3.2.1.
     
*
     
* @param
  
bits random bits
     
* @return the next pseudorandom value from this random number
     
*
         
generator's sequence
     
* @since
  
1.1
     
*/

    
protected int next(int bits) {
        
long oldseed, nextseed;
        
AtomicLong seed = this.seed;
        
do {
            
oldseed = seed.get();
            
nextseed = (oldseed * multiplier + addend) & mask;
        
} while (!seed.compareAndSet(oldseed, nextseed));
        
return (int)(nextseed >>> (48 - bits));
    
}

    
/**
     
* Generates random bytes and places them into a user-supplied
     
* byte array.
  
The number of random bytes produced is equal to
     
* the length of the byte array.
     
*
     
* <p>The method {@code nextBytes} is implemented by class {@code Random}
     
* as if by:
     
*
  
<pre> {@code
     
* public void nextBytes(byte[] bytes) {
     
*
   
for (int i = 0; i < bytes.length; )
     
*for (int rnd = nextInt(), n = Math.min(bytes.length - i, 4);
     
*
          
n-- > 0; rnd >>= 8)
     
*
       
bytes[i++] = (byte)rnd;
     
* }}</pre>
     
*
     
* @param
  
bytes the byte array to fill with random bytes
     
* @throws NullPointerException if the byte array is null
     
* @since
  
1.1
     
*/

    
public void nextBytes(byte[] bytes) {
        
for (int i = 0, len = bytes.length; i < len; )
            
for (int rnd = nextInt(),
                     
n = Math.min(len - i, Integer.SIZE/Byte.SIZE);
                 
n-- > 0; rnd >>= Byte.SIZE)
                
bytes[i++] = (byte)rnd;
    
}

    
/**
     
* The form of nextLong used by LongStream Spliterators.
  
If
     
* origin is greater than bound, acts as unbounded form of
     
* nextLong, else as bounded form.
     
*
     
* @param origin the least value, unless greater than bound
     
* @param bound the upper bound (exclusive), must not equal origin
     
* @return a pseudorandom value
     
*/

    
final long internalNextLong(long origin, long bound) {
        
long r = nextLong();
        
if (origin < bound) {
            
long n = bound - origin, m = n - 1;
            
if ((n & m) == 0L)
  
// power of two
                
r = (r & m) + origin;
            
else if (n > 0L) {
  
// reject over-represented candidates
                
for (long u = r >>> 1;
            
// ensure nonnegative
                     
u + m - (r = u % n) < 0L;
    
// rejection check
                     
u = nextLong() >>> 1) // retry
                    
;
                
r += origin;
            
}
            
else {
              
// range not representable as long
                
while (r < origin || r >= bound)
                    
r = nextLong();
            
}
        
}
        
return r;
    
}

    
/**
     
* The form of nextInt used by IntStream Spliterators.
     
* For the unbounded case: uses nextInt().
     
* For the bounded case with representable range: uses nextInt(int bound)
     
* For the bounded case with unrepresentable range: uses nextInt()
     
*
     
* @param origin the least value, unless greater than bound
     
* @param bound the upper bound (exclusive), must not equal origin
     
* @return a pseudorandom value
     
*/

    
final int internalNextInt(int origin, int bound) {
        
if (origin < bound) {
            
int n = bound - origin;
            
if (n > 0) {
                
return nextInt(n) + origin;
            
}
            
else {
  
// range not representable as int
                
int r;
                
do {
                    
r = nextInt();
                
} while (r < origin || r >= bound);
                
return r;
            
}
        
}
        
else {
            
return nextInt();
        
}
    
}

    
/**
     
* The form of nextDouble used by DoubleStream Spliterators.
     
*
     
* @param origin the least value, unless greater than bound
     
* @param bound the upper bound (exclusive), must not equal origin
     
* @return a pseudorandom value
     
*/

    
final double internalNextDouble(double origin, double bound) {
        
double r = nextDouble();
        
if (origin < bound) {
            
r = r * (bound - origin) + origin;
            
if (r >= bound) // correct for rounding
                
r = Double.longBitsToDouble(Double.doubleToLongBits(bound) - 1);
        
}
        
return r;
    
}

    
/**
     
* Returns the next pseudorandom, uniformly distributed {@code int}
     
* value from this random number generator's sequence. The general
     
* contract of {@code nextInt} is that one {@code int} value is
     
* pseudorandomly generated and returned. All 2<sup>32</sup> possible
     
* {@code int} values are produced with (approximately) equal probability.
     
*
     
* <p>The method {@code nextInt} is implemented by class {@code Random}
     
* as if by:
     
*
  
<pre> {@code
     
* public int nextInt() {
     
*
   
return next(32);
     
* }}</pre>
     
*
     
* @return the next pseudorandom, uniformly distributed {@code int}
     
*
         
value from this random number generator's sequence
     
*/

    
public int nextInt() {
        
return next(32);
    
}

    
/**
     
* Returns a pseudorandom, uniformly distributed {@code int} value
     
* between 0 (inclusive) and the specified value (exclusive), drawn from
     
* this random number generator's sequence.
  
The general contract of
     
* {@code nextInt} is that one {@code int} value in the specified range
     
* is pseudorandomly generated and returned.
  
All {@code bound} possible
     
* {@code int} values are produced with (approximately) equal
     
* probability.
  
The method {@code nextInt(int bound)} is implemented by
     
* class {@code Random} as if by:
     
*
  
<pre> {@code
     
* public int nextInt(int bound) {
     
*
   
if (bound <= 0)
     
*throw new IllegalArgumentException("bound must be positive");
     
*
     
*
   
if ((bound & -bound) == bound)
  
// i.e., bound is a power of 2
     
*return (int)((bound * (long)next(31)) >> 31);
     
*
     
*
   
int bits, val;
     
*
   
do {
     
*
       
bits = next(31);
     
*
       
val = bits % bound;
     
*
   
} while (bits - val + (bound-1) < 0);
     
*
   
return val;
     
* }}</pre>
     
*
     
* <p>The hedge "approximately" is used in the foregoing description only
     
* because the next method is only approximately an unbiased source of
     
* independently chosen bits.
  
If it were a perfect source of randomly
     
* chosen bits, then the algorithm shown would choose {@code int}
     
* values from the stated range with perfect uniformity.
     
* <p>
     
* The algorithm is slightly tricky.
  
It rejects values that would result
     
* in an uneven distribution (due to the fact that 2^31 is not divisible
     
* by n). The probability of a value being rejected depends on n.
  
The
     
* worst case is n=2^30+1, for which the probability of a reject is 1/2,
     
* and the expected number of iterations before the loop terminates is 2.
     
* <p>
     
* The algorithm treats the case where n is a power of two specially: it
     
* returns the correct number of high-order bits from the underlying
     
* pseudo-random number generator.
  
In the absence of special treatment,
     
* the correct number of <i>low-order</i> bits would be returned.
  
Linear
     
* congruential pseudo-random number generators such as the one
     
* implemented by this class are known to have short periods in the
     
* sequence of values of their low-order bits.
  
Thus, this special case
     
* greatly increases the length of the sequence of values returned by
     
* successive calls to this method if n is a small power of two.
     
*
     
* @param bound the upper bound (exclusive).
  
Must be positive.
     
* @return the next pseudorandom, uniformly distributed {@code int}
     
*
         
value between zero (inclusive) and {@code bound} (exclusive)
     
*
         
from this random number generator's sequence
     
* @throws IllegalArgumentException if bound is not positive
     
* @since 1.2
     
*/

    
public int nextInt(int bound) {
        
if (bound <= 0)
            
throw new IllegalArgumentException(BadBound);

        
int r = next(31);
        
int m = bound - 1;
        
if ((bound & m) == 0)
  
// i.e., bound is a power of 2
            
r = (int)((bound * (long)r) >> 31);
        
else {
            
for (int u = r;
                 
u - (r = u % bound) + m < 0;
                 
u = next(31))
                
;
        
}
        
return r;
    
}

    
/**
     
* Returns the next pseudorandom, uniformly distributed {@code long}
     
* value from this random number generator's sequence. The general
     
* contract of {@code nextLong} is that one {@code long} value is
     
* pseudorandomly generated and returned.
     
*
     
* <p>The method {@code nextLong} is implemented by class {@code Random}
     
* as if by:
     
*
  
<pre> {@code
     
* public long nextLong() {
     
*
   
return ((long)next(32) << 32) + next(32);
     
* }}</pre>
     
*
     
* Because class {@code Random} uses a seed with only 48 bits,
     
* this algorithm will not return all possible {@code long} values.
     
*
     
* @return the next pseudorandom, uniformly distributed {@code long}
     
*
         
value from this random number generator's sequence
     
*/

    
public long nextLong() {
        
// it's okay that the bottom word remains signed.
        
return ((long)(next(32)) << 32) + next(32);
    
}

    
/**
     
* Returns the next pseudorandom, uniformly distributed
     
* {@code boolean} value from this random number generator's
     
* sequence. The general contract of {@code nextBoolean} is that one
     
* {@code boolean} value is pseudorandomly generated and returned.
  
The
     
* values {@code true} and {@code false} are produced with
     
* (approximately) equal probability.
     
*
     
* <p>The method {@code nextBoolean} is implemented by class {@code Random}
     
* as if by:
     
*
  
<pre> {@code
     
* public boolean nextBoolean() {
     
*
   
return next(1) != 0;
     
* }}</pre>
     
*
     
* @return the next pseudorandom, uniformly distributed
     
*
         
{@code boolean} value from this random number generator's
     
*
         
sequence
     
* @since 1.2
     
*/

    
public boolean nextBoolean() {
        
return next(1) != 0;
    
}

    
/**
     
* Returns the next pseudorandom, uniformly distributed {@code float}
     
* value between {@code 0.0} and {@code 1.0} from this random
     
* number generator's sequence.
     
*
     
* <p>The general contract of {@code nextFloat} is that one
     
* {@code float} value, chosen (approximately) uniformly from the
     
* range {@code 0.0f} (inclusive) to {@code 1.0f} (exclusive), is
     
* pseudorandomly generated and returned. All 2<sup>24</sup> possible
     
* {@code float} values of the form <i>m&nbsp;x&nbsp;</i>2<sup>-24</sup>,
     
* where <i>m</i> is a positive integer less than 2<sup>24</sup>, are
     
* produced with (approximately) equal probability.
     
*
     
* <p>The method {@code nextFloat} is implemented by class {@code Random}
     
* as if by:
     
*
  
<pre> {@code
     
* public float nextFloat() {
     
*
   
return next(24) / ((float)(1 << 24));
     
* }}</pre>
     
*
     
* <p>The hedge "approximately" is used in the foregoing description only
     
* because the next method is only approximately an unbiased source of
     
* independently chosen bits. If it were a perfect source of randomly
     
* chosen bits, then the algorithm shown would choose {@code float}
     
* values from the stated range with perfect uniformity.<p>
     
* [In early versions of Java, the result was incorrectly calculated as:
     
*
  
<pre> {@code
     
*
   
return next(30) / ((float)(1 << 30));}</pre>
     
* This might seem to be equivalent, if not better, but in fact it
     
* introduced a slight nonuniformity because of the bias in the rounding
     
* of floating-point numbers: it was slightly more likely that the
     
* low-order bit of the significand would be 0 than that it would be 1.]
     
*
     
* @return the next pseudorandom, uniformly distributed {@code float}
     
*
         
value between {@code 0.0} and {@code 1.0} from this
     
*
         
random number generator's sequence
     
*/

    
public float nextFloat() {
        
return next(24) / ((float)(1 << 24));
    
}

    
/**
     
* Returns the next pseudorandom, uniformly distributed
     
* {@code double} value between {@code 0.0} and
     
* {@code 1.0} from this random number generator's sequence.
     
*
     
* <p>The general contract of {@code nextDouble} is that one
     
* {@code double} value, chosen (approximately) uniformly from the
     
* range {@code 0.0d} (inclusive) to {@code 1.0d} (exclusive), is
     
* pseudorandomly generated and returned.
     
*
     
* <p>The method {@code nextDouble} is implemented by class {@code Random}
     
* as if by:
     
*
  
<pre> {@code
     
* public double nextDouble() {
     
*
   
return (((long)next(26) << 27) + next(27))
     
*/ (double)(1L << 53);
     
* }}</pre>
     
*
     
* <p>The hedge "approximately" is used in the foregoing description only
     
* because the {@code next} method is only approximately an unbiased
     
* source of independently chosen bits. If it were a perfect source of
     
* randomly chosen bits, then the algorithm shown would choose
     
* {@code double} values from the stated range with perfect uniformity.
     
* <p>[In early versions of Java, the result was incorrectly calculated as:
     
*
  
<pre> {@code
     
*
   
return (((long)next(27) << 27) + next(27))
     
*/ (double)(1L << 54);}</pre>
     
* This might seem to be equivalent, if not better, but in fact it
     
* introduced a large nonuniformity because of the bias in the rounding
     
* of floating-point numbers: it was three times as likely that the
     
* low-order bit of the significand would be 0 than that it would be 1!
     
* This nonuniformity probably doesn't matter much in practice, but we
     
* strive for perfection.]
     
*
     
* @return the next pseudorandom, uniformly distributed {@code double}
     
*
         
value between {@code 0.0} and {@code 1.0} from this
     
*
         
random number generator's sequence
     
* @see Math#random
     
*/

    
public double nextDouble() {
        
return (((long)(next(26)) << 27) + next(27)) * DOUBLE_UNIT;
    
}

    
private double nextNextGaussian;
    
private boolean haveNextNextGaussian = false;

    
/**
     
* Returns the next pseudorandom, Gaussian ("normally") distributed
     
* {@code double} value with mean {@code 0.0} and standard
     
* deviation {@code 1.0} from this random number generator's sequence.
     
* <p>
     
* The general contract of {@code nextGaussian} is that one
     
* {@code double} value, chosen from (approximately) the usual
     
* normal distribution with mean {@code 0.0} and standard deviation
     
* {@code 1.0}, is pseudorandomly generated and returned.
     
*
     
* <p>The method {@code nextGaussian} is implemented by class
     
* {@code Random} as if by a threadsafe version of the following:
     
*
  
<pre> {@code
     
* private double nextNextGaussian;
     
* private boolean haveNextNextGaussian = false;
     
*
     
* public double nextGaussian() {
     
*
   
if (haveNextNextGaussian) {
     
*haveNextNextGaussian = false;
     
*return nextNextGaussian;
     
*
   
} else {
     
*double v1, v2, s;
     
*do {
     
*
       
v1 = 2 * nextDouble() - 1;
   
// between -1.0 and 1.0
     
*
       
v2 = 2 * nextDouble() - 1;
   
// between -1.0 and 1.0
     
*
       
s = v1 * v1 + v2 * v2;
     
*} while (s >= 1 || s == 0);
     
*double multiplier = StrictMath.sqrt(-2 * StrictMath.log(s)/s);
     
*nextNextGaussian = v2 * multiplier;
     
*haveNextNextGaussian = true;
     
*return v1 * multiplier;
     
*
   
}
     
* }}</pre>
     
* This uses the <i>polar method</i> of G. E. P. Box, M. E. Muller, and
     
* G. Marsaglia, as described by Donald E. Knuth in <i>The Art of
     
* Computer Programming</i>, Volume 3: <i>Seminumerical Algorithms</i>,
     
* section 3.4.1, subsection C, algorithm P. Note that it generates two
     
* independent values at the cost of only one call to {@code StrictMath.log}
     
* and one call to {@code StrictMath.sqrt}.
     
*
     
* @return the next pseudorandom, Gaussian ("normally") distributed
     
*
         
{@code double} value with mean {@code 0.0} and
     
*
         
standard deviation {@code 1.0} from this random number
     
*
         
generator's sequence
     
*/

    
synchronized public double nextGaussian() {
        
// See Knuth, ACP, Section 3.4.1 Algorithm C.
        
if (haveNextNextGaussian) {
            
haveNextNextGaussian = false;
            
return nextNextGaussian;
        
} else {
            
double v1, v2, s;
            
do {
                
v1 = 2 * nextDouble() - 1; // between -1 and 1
                
v2 = 2 * nextDouble() - 1; // between -1 and 1
                
s = v1 * v1 + v2 * v2;
            
} while (s >= 1 || s == 0);
            
double multiplier = StrictMath.sqrt(-2 * StrictMath.log(s)/s);
            
nextNextGaussian = v2 * multiplier;
            
haveNextNextGaussian = true;
            
return v1 * multiplier;
        
}
    
}

    
// stream methods, coded in a way intended to better isolate for
    
// maintenance purposes the small differences across forms.

    
/**
     
* Returns a stream producing the given {@code streamSize} number of
     
* pseudorandom {@code int} values.
     
*
     
* <p>A pseudorandom {@code int} value is generated as if it's the result of
     
* calling the method
 
.
     
*
     
* @param streamSize the number of values to generate
     
* @return a stream of pseudorandom {@code int} values
     
* @throws IllegalArgumentException if {@code streamSize} is
     
*
         
less than zero
     
* @since 1.8
     
*/

    
public IntStream ints(long streamSize) {
        
if (streamSize < 0L)
            
throw new IllegalArgumentException(BadSize);
        
return StreamSupport.intStream
                
(new RandomIntsSpliterator
                         
(this, 0L, streamSize, Integer.MAX_VALUE, 0),
                 
false);
    
}

    
/**
     
* Returns an effectively unlimited stream of pseudorandom {@code int}
     
* values.
     
*
     
* <p>A pseudorandom {@code int} value is generated as if it's the result of
     
* calling the method
 
.
     
*
     
* @implNote This method is implemented to be equivalent to {@code
     
* ints(Long.MAX_VALUE)}.
     
*
     
* @return a stream of pseudorandom {@code int} values
     
* @since 1.8
     
*/

    
public IntStream ints() {
        
return StreamSupport.intStream
                
(new RandomIntsSpliterator
                         
(this, 0L, Long.MAX_VALUE, Integer.MAX_VALUE, 0),
                 
false);
    
}

    
/**
     
* Returns a stream producing the given {@code streamSize} number
     
* of pseudorandom {@code int} values, each conforming to the given
     
* origin (inclusive) and bound (exclusive).
     
*
     
* <p>A pseudorandom {@code int} value is generated as if it's the result of
     
* calling the following method with the origin and bound:
     
* <pre> {@code
     
* int nextInt(int origin, int bound) {
     
*
   
int n = bound - origin;
     
*
   
if (n > 0) {
     
*return nextInt(n) + origin;
     
*
   
}
     
*
   
else {
  
// range not representable as int
     
*int r;
     
*do {
     
*
       
r = nextInt();
     
*} while (r < origin || r >= bound);
     
*return r;
     
*
   
}
     
* }}</pre>
     
*
     
* @param streamSize the number of values to generate
     
* @param randomNumberOrigin the origin (inclusive) of each random value
     
* @param randomNumberBound the bound (exclusive) of each random value
     
* @return a stream of pseudorandom {@code int} values,
     
*
         
each with the given origin (inclusive) and bound (exclusive)
     
* @throws IllegalArgumentException if {@code streamSize} is
     
*
         
less than zero, or {@code randomNumberOrigin}
     
*
         
is greater than or equal to {@code randomNumberBound}
     
* @since 1.8
     
*/

    
public IntStream ints(long streamSize, int randomNumberOrigin,
                          
int randomNumberBound) {
        
if (streamSize < 0L)
            
throw new IllegalArgumentException(BadSize);
        
if (randomNumberOrigin >= randomNumberBound)
            
throw new IllegalArgumentException(BadRange);
        
return StreamSupport.intStream
                
(new RandomIntsSpliterator
                         
(this, 0L, streamSize, randomNumberOrigin, randomNumberBound),
                 
false);
    
}

    
/**
     
* Returns an effectively unlimited stream of pseudorandom {@code
     
* int} values, each conforming to the given origin (inclusive) and bound
     
* (exclusive).
     
*
     
* <p>A pseudorandom {@code int} value is generated as if it's the result of
     
* calling the following method with the origin and bound:
     
* <pre> {@code
     
* int nextInt(int origin, int bound) {
     
*
   
int n = bound - origin;
     
*
   
if (n > 0) {
     
*return nextInt(n) + origin;
     
*
   
}
     
*
   
else {
  
// range not representable as int
     
*int r;
     
*do {
     
*
       
r = nextInt();
     
*} while (r < origin || r >= bound);
     
*return r;
     
*
   
}
     
* }}</pre>
     
*
     
* @implNote This method is implemented to be equivalent to {@code
     
* ints(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound)}.
     
*
     
* @param randomNumberOrigin the origin (inclusive) of each random value
     
* @param randomNumberBound the bound (exclusive) of each random value
     
* @return a stream of pseudorandom {@code int} values,
     
*
         
each with the given origin (inclusive) and bound (exclusive)
     
* @throws IllegalArgumentException if {@code randomNumberOrigin}
     
*
         
is greater than or equal to {@code randomNumberBound}
     
* @since 1.8
     
*/

    
public IntStream ints(int randomNumberOrigin, int randomNumberBound) {
        
if (randomNumberOrigin >= randomNumberBound)
            
throw new IllegalArgumentException(BadRange);
        
return StreamSupport.intStream
                
(new RandomIntsSpliterator
                         
(this, 0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound),
                 
false);
    
}

    
/**
     
* Returns a stream producing the given {@code streamSize} number of
     
* pseudorandom {@code long} values.
     
*
     
* <p>A pseudorandom {@code long} value is generated as if it's the result
     
* of calling the method
 
.
     
*
     
* @param streamSize the number of values to generate
     
* @return a stream of pseudorandom {@code long} values
     
* @throws IllegalArgumentException if {@code streamSize} is
     
*
         
less than zero
     
* @since 1.8
     
*/

    
public LongStream longs(long streamSize) {
        
if (streamSize < 0L)
            
throw new IllegalArgumentException(BadSize);
        
return StreamSupport.longStream
                
(new RandomLongsSpliterator
                         
(this, 0L, streamSize, Long.MAX_VALUE, 0L),
                 
false);
    
}

    
/**
     
* Returns an effectively unlimited stream of pseudorandom {@code long}
     
* values.
     
*
     
* <p>A pseudorandom {@code long} value is generated as if it's the result
     
* of calling the method
 
.
     
*
     
* @implNote This method is implemented to be equivalent to {@code
     
* longs(Long.MAX_VALUE)}.
     
*
     
* @return a stream of pseudorandom {@code long} values
     
* @since 1.8
     
*/

    
public LongStream longs() {
        
return StreamSupport.longStream
                
(new RandomLongsSpliterator
                         
(this, 0L, Long.MAX_VALUE, Long.MAX_VALUE, 0L),
                 
false);
    
}

    
/**
     
* Returns a stream producing the given {@code streamSize} number of
     
* pseudorandom {@code long}, each conforming to the given origin
     
* (inclusive) and bound (exclusive).
     
*
     
* <p>A pseudorandom {@code long} value is generated as if it's the result
     
* of calling the following method with the origin and bound:
     
* <pre> {@code
     
* long nextLong(long origin, long bound) {
     
*
   
long r = nextLong();
     
*
   
long n = bound - origin, m = n - 1;
     
*
   
if ((n & m) == 0L)
  
// power of two
     
*r = (r & m) + origin;
     
*
   
else if (n > 0L) {
  
// reject over-represented candidates
     
*for (long u = r >>> 1;
            
// ensure nonnegative
     
*
          
u + m - (r = u % n) < 0L;
    
// rejection check
     
*
          
u = nextLong() >>> 1) // retry
     
*
         
;
     
*r += origin;
     
*
   
}
     
*
   
else {
              
// range not representable as long
     
*while (r < origin || r >= bound)
     
*
       
r = nextLong();
     
*
   
}
     
*
   
return r;
     
* }}</pre>
     
*
     
* @param streamSize the number of values to generate
     
* @param randomNumberOrigin the origin (inclusive) of each random value
     
* @param randomNumberBound the bound (exclusive) of each random value
     
* @return a stream of pseudorandom {@code long} values,
     
*
         
each with the given origin (inclusive) and bound (exclusive)
     
* @throws IllegalArgumentException if {@code streamSize} is
     
*
         
less than zero, or {@code randomNumberOrigin}
     
*
         
is greater than or equal to {@code randomNumberBound}
     
* @since 1.8
     
*/

    
public LongStream longs(long streamSize, long randomNumberOrigin,
                            
long randomNumberBound) {
        
if (streamSize < 0L)
            
throw new IllegalArgumentException(BadSize);
        
if (randomNumberOrigin >= randomNumberBound)
            
throw new IllegalArgumentException(BadRange);
        
return StreamSupport.longStream
                
(new RandomLongsSpliterator
                         
(this, 0L, streamSize, randomNumberOrigin, randomNumberBound),
                 
false);
    
}

    
/**
     
* Returns an effectively unlimited stream of pseudorandom {@code
     
* long} values, each conforming to the given origin (inclusive) and bound
     
* (exclusive).
     
*
     
* <p>A pseudorandom {@code long} value is generated as if it's the result
     
* of calling the following method with the origin and bound:
     
* <pre> {@code
     
* long nextLong(long origin, long bound) {
     
*
   
long r = nextLong();
     
*
   
long n = bound - origin, m = n - 1;
     
*
   
if ((n & m) == 0L)
  
// power of two
     
*r = (r & m) + origin;
     
*
   
else if (n > 0L) {
  
// reject over-represented candidates
     
*for (long u = r >>> 1;
            
// ensure nonnegative
     
*
          
u + m - (r = u % n) < 0L;
    
// rejection check
     
*
          
u = nextLong() >>> 1) // retry
     
*
         
;
     
*r += origin;
     
*
   
}
     
*
   
else {
              
// range not representable as long
     
*while (r < origin || r >= bound)
     
*
       
r = nextLong();
     
*
   
}
     
*
   
return r;
     
* }}</pre>
     
*
     
* @implNote This method is implemented to be equivalent to {@code
     
* longs(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound)}.
     
*
     
* @param randomNumberOrigin the origin (inclusive) of each random value
     
* @param randomNumberBound the bound (exclusive) of each random value
     
* @return a stream of pseudorandom {@code long} values,
     
*
         
each with the given origin (inclusive) and bound (exclusive)
     
* @throws IllegalArgumentException if {@code randomNumberOrigin}
     
*
         
is greater than or equal to {@code randomNumberBound}
     
* @since 1.8
     
*/

    
public LongStream longs(long randomNumberOrigin, long randomNumberBound) {
        
if (randomNumberOrigin >= randomNumberBound)
            
throw new IllegalArgumentException(BadRange);
        
return StreamSupport.longStream
                
(new RandomLongsSpliterator
                         
(this, 0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound),
                 
false);
    
}

    
/**
     
* Returns a stream producing the given {@code streamSize} number of
     
* pseudorandom {@code double} values, each between zero
     
* (inclusive) and one (exclusive).
     
*
     
* <p>A pseudorandom {@code double} value is generated as if it's the result
     
* of calling the method
 
.
     
*
     
* @param streamSize the number of values to generate
     
* @return a stream of {@code double} values
     
* @throws IllegalArgumentException if {@code streamSize} is
     
*
         
less than zero
     
* @since 1.8
     
*/

    
public DoubleStream doubles(long streamSize) {
        
if (streamSize < 0L)
            
throw new IllegalArgumentException(BadSize);
        
return StreamSupport.doubleStream
                
(new RandomDoublesSpliterator
                         
(this, 0L, streamSize, Double.MAX_VALUE, 0.0),
                 
false);
    
}

    
/**
     
* Returns an effectively unlimited stream of pseudorandom {@code
     
* double} values, each between zero (inclusive) and one
     
* (exclusive).
     
*
     
* <p>A pseudorandom {@code double} value is generated as if it's the result
     
* of calling the method
 
.
     
*
     
* @implNote This method is implemented to be equivalent to {@code
     
* doubles(Long.MAX_VALUE)}.
     
*
     
* @return a stream of pseudorandom {@code double} values
     
* @since 1.8
     
*/

    
public DoubleStream doubles() {
        
return StreamSupport.doubleStream
                
(new RandomDoublesSpliterator
                         
(this, 0L, Long.MAX_VALUE, Double.MAX_VALUE, 0.0),
                 
false);
    
}

    
/**
     
* Returns a stream producing the given {@code streamSize} number of
     
* pseudorandom {@code double} values, each conforming to the given origin
     
* (inclusive) and bound (exclusive).
     
*
     
* <p>A pseudorandom {@code double} value is generated as if it's the result
     
* of calling the following method with the origin and bound:
     
* <pre> {@code
     
* double nextDouble(double origin, double bound) {
     
*
   
double r = nextDouble();
     
*
   
r = r * (bound - origin) + origin;
     
*
   
if (r >= bound) // correct for rounding
     
*r = Math.nextDown(bound);
     
*
   
return r;
     
* }}</pre>
     
*
     
* @param streamSize the number of values to generate
     
* @param randomNumberOrigin the origin (inclusive) of each random value
     
* @param randomNumberBound the bound (exclusive) of each random value
     
* @return a stream of pseudorandom {@code double} values,
     
*
         
each with the given origin (inclusive) and bound (exclusive)
     
* @throws IllegalArgumentException if {@code streamSize} is
     
*
         
less than zero
     
* @throws IllegalArgumentException if {@code randomNumberOrigin}
     
*
         
is greater than or equal to {@code randomNumberBound}
     
* @since 1.8
     
*/

    
public DoubleStream doubles(long streamSize, double randomNumberOrigin,
                                
double randomNumberBound) {
        
if (streamSize < 0L)
            
throw new IllegalArgumentException(BadSize);
        
if (!(randomNumberOrigin < randomNumberBound))
            
throw new IllegalArgumentException(BadRange);
        
return StreamSupport.doubleStream
                
(new RandomDoublesSpliterator
                         
(this, 0L, streamSize, randomNumberOrigin, randomNumberBound),
                 
false);
    
}

    
/**
     
* Returns an effectively unlimited stream of pseudorandom {@code
     
* double} values, each conforming to the given origin (inclusive) and bound
     
* (exclusive).
     
*
     
* <p>A pseudorandom {@code double} value is generated as if it's the result
     
* of calling the following method with the origin and bound:
     
* <pre> {@code
     
* double nextDouble(double origin, double bound) {
     
*
   
double r = nextDouble();
     
*
   
r = r * (bound - origin) + origin;
     
*
   
if (r >= bound) // correct for rounding
     
*r = Math.nextDown(bound);
     
*
   
return r;
     
* }}</pre>
     
*
     
* @implNote This method is implemented to be equivalent to {@code
     
* doubles(Long.MAX_VALUE, randomNumberOrigin, randomNumberBound)}.
     
*
     
* @param randomNumberOrigin the origin (inclusive) of each random value
     
* @param randomNumberBound the bound (exclusive) of each random value
     
* @return a stream of pseudorandom {@code double} values,
     
*
         
each with the given origin (inclusive) and bound (exclusive)
     
* @throws IllegalArgumentException if {@code randomNumberOrigin}
     
*
         
is greater than or equal to {@code randomNumberBound}
     
* @since 1.8
     
*/

    
public DoubleStream doubles(double randomNumberOrigin, double randomNumberBound) {
        
if (!(randomNumberOrigin < randomNumberBound))
            
throw new IllegalArgumentException(BadRange);
        
return StreamSupport.doubleStream
                
(new RandomDoublesSpliterator
                         
(this, 0L, Long.MAX_VALUE, randomNumberOrigin, randomNumberBound),
                 
false);
    
}

    
/**
     
* Spliterator for int streams.
  
We multiplex the four int
     
* versions into one class by treating a bound less than origin as
     
* unbounded, and also by treating "infinite" as equivalent to
     
* Long.MAX_VALUE. For splits, it uses the standard divide-by-two
     
* approach. The long and double versions of this class are
     
* identical except for types.
     
*/

    
static final class RandomIntsSpliterator implements Spliterator.OfInt {
        
final Random rng;
        
long index;
        
final long fence;
        
final int origin;
        
final int bound;
        
RandomIntsSpliterator(Random rng, long index, long fence,
                              
int origin, int bound) {
            
this.rng = rng; this.index = index; this.fence = fence;
            
this.origin = origin; this.bound = bound;
        
}

        
public RandomIntsSpliterator trySplit() {
            
long i = index, m = (i + fence) >>> 1;
            
return (m <= i) ? null :
                   
new RandomIntsSpliterator(rng, i, index = m, origin, bound);
        
}

        
public long estimateSize() {
            
return fence - index;
        
}

        
public int characteristics() {
            
return (Spliterator.SIZED | Spliterator.SUBSIZED |
                    
Spliterator.NONNULL | Spliterator.IMMUTABLE);
        
}

        
public boolean tryAdvance(IntConsumer consumer) {
            
if (consumer == null) throw new NullPointerException();
            
long i = index, f = fence;
            
if (i < f) {
                
consumer.accept(rng.internalNextInt(origin, bound));
                
index = i + 1;
                
return true;
            
}
            
return false;
        
}

        
public void forEachRemaining(IntConsumer consumer) {
            
if (consumer == null) throw new NullPointerException();
            
long i = index, f = fence;
            
if (i < f) {
                
index = f;
                
Random r = rng;
                
int o = origin, b = bound;
                
do {
                    
consumer.accept(r.internalNextInt(o, b));
                
} while (++i < f);
            
}
        
}
    
}

    
/**
     
* Spliterator for long streams.
     
*/
    
static final class RandomLongsSpliterator implements Spliterator.OfLong {
        
final Random rng;
        
long index;
        
final long fence;
        
final long origin;
        
final long bound;
        
RandomLongsSpliterator(Random rng, long index, long fence,
                               
long origin, long bound) {
            
this.rng = rng; this.index = index; this.fence = fence;
            
this.origin = origin; this.bound = bound;
        
}

        
public RandomLongsSpliterator trySplit() {
            
long i = index, m = (i + fence) >>> 1;
            
return (m <= i) ? null :
                   
new RandomLongsSpliterator(rng, i, index = m, origin, bound);
        
}

        
public long estimateSize() {
            
return fence - index;
        
}

        
public int characteristics() {
            
return (Spliterator.SIZED | Spliterator.SUBSIZED |
                    
Spliterator.NONNULL | Spliterator.IMMUTABLE);
        
}

        
public boolean tryAdvance(LongConsumer consumer) {
            
if (consumer == null) throw new NullPointerException();
            
long i = index, f = fence;
            
if (i < f) {
                
consumer.accept(rng.internalNextLong(origin, bound));
                
index = i + 1;
                
return true;
            
}
            
return false;
        
}

        
public void forEachRemaining(LongConsumer consumer) {
            
if (consumer == null) throw new NullPointerException();
            
long i = index, f = fence;
            
if (i < f) {
                
index = f;
                
Random r = rng;
                
long o = origin, b = bound;
                
do {
                    
consumer.accept(r.internalNextLong(o, b));
                
} while (++i < f);
            
}
        
}

    
}

    
/**
     
* Spliterator for double streams.
     
*/
    
static final class RandomDoublesSpliterator implements Spliterator.OfDouble {
        
final Random rng;
        
long index;
        
final long fence;
        
final double origin;
        
final double bound;
        
RandomDoublesSpliterator(Random rng, long index, long fence,
                                 
double origin, double bound) {
            
this.rng = rng; this.index = index; this.fence = fence;
            
this.origin = origin; this.bound = bound;
        
}

        
public RandomDoublesSpliterator trySplit() {
            
long i = index, m = (i + fence) >>> 1;
            
return (m <= i) ? null :
                   
new RandomDoublesSpliterator(rng, i, index = m, origin, bound);
        
}

        
public long estimateSize() {
            
return fence - index;
        
}

        
public int characteristics() {
            
return (Spliterator.SIZED | Spliterator.SUBSIZED |
                    
Spliterator.NONNULL | Spliterator.IMMUTABLE);
        
}

        
public boolean tryAdvance(DoubleConsumer consumer) {
            
if (consumer == null) throw new NullPointerException();
            
long i = index, f = fence;
            
if (i < f) {
                
consumer.accept(rng.internalNextDouble(origin, bound));
                
index = i + 1;
                
return true;
            
}
            
return false;
        
}

        
public void forEachRemaining(DoubleConsumer consumer) {
            
if (consumer == null) throw new NullPointerException();
            
long i = index, f = fence;
            
if (i < f) {
                
index = f;
                
Random r = rng;
                
double o = origin, b = bound;
                
do {
                    
consumer.accept(r.internalNextDouble(o, b));
                
} while (++i < f);
            
}
        
}
    
}

    
/**
     
* Serializable fields for Random.
     
*
     
* @serialField
    
seed long
     
*
              
seed for random computations
     
* @serialField
    
nextNextGaussian double
     
*
              
next Gaussian to be returned
     
* @serialField
      
haveNextNextGaussian boolean
     
*
              
nextNextGaussian is valid
     
*/

    
private static final ObjectStreamField[] serialPersistentFields = {
        
new ObjectStreamField("seed", Long.TYPE),
        
new ObjectStreamField("nextNextGaussian", Double.TYPE),
        
new ObjectStreamField("haveNextNextGaussian", Boolean.TYPE)
    
};

    
/**
     
* Reconstitute the {@code Random} instance from a stream (that is,
     
* deserialize it).
     
*/

    
private void readObject(java.io.ObjectInputStream s)
        
throws java.io.IOException, ClassNotFoundException {

        
ObjectInputStream.GetField fields = s.readFields();

        
// The seed is read in as {@code long} for
        
// historical reasons, but it is converted to an AtomicLong.
        
long seedVal = fields.get("seed", -1L);
        
if (seedVal < 0)
          
throw new java.io.StreamCorruptedException(
                              
"Random: invalid seed");
        
resetSeed(seedVal);
        
nextNextGaussian = fields.get("nextNextGaussian", 0.0);
        
haveNextNextGaussian = fields.get("haveNextNextGaussian", false);
    
}

    
/**
     
* Save the {@code Random} instance to a stream.
     
*/
    
synchronized private void writeObject(ObjectOutputStream s)
        
throws IOException {

        
// set the values of the Serializable fields
        
ObjectOutputStream.PutField fields = s.putFields();

        
// The seed is serialized as a long for historical reasons.
        
fields.put("seed", seed.get());
        
fields.put("nextNextGaussian", nextNextGaussian);
        
fields.put("haveNextNextGaussian", haveNextNextGaussian);

        
// save them
        
s.writeFields();
    
}

    
// Support for resetting seed while deserializing
    
private static final Unsafe unsafe = Unsafe.getUnsafe();
    
private static final long seedOffset;
    
static {
        
try {
            
seedOffset = unsafe.objectFieldOffset
                
(Random.class.getDeclaredField("seed"));
        
} catch (Exception ex) { throw new Error(ex); }
    
}
    
private void resetSeed(long seedVal) {
        
unsafe.putObjectVolatile(this, seedOffset, new AtomicLong(seedVal));
    
}
}