/**************************************************************************
* Copyright (c) 2001 by Punch Telematix. All rights reserved. *
* *
* Redistribution and use in source and binary forms, with or without *
* modification, are permitted provided that the following conditions *
* are met: *
* 1. Redistributions of source code must retain the above copyright *
* notice, this list of conditions and the following disclaimer. *
* 2. Redistributions in binary form must reproduce the above copyright *
* notice, this list of conditions and the following disclaimer in the *
* documentation and/or other materials provided with the distribution. *
* 3. Neither the name of Punch Telematix nor the names of *
* other contributors may be used to endorse or promote products *
* derived from this software without specific prior written permission.*
* *
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED *
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF *
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. *
* IN NO EVENT SHALL PUNCH TELEMATIX OR OTHER CONTRIBUTORS BE LIABLE *
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR *
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF *
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR *
* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, *
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* IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. *
**************************************************************************/
/*
** $Id: Random.java,v 1.2 2006/04/18 11:35:28 cvs Exp $
*/
package java.util;
public class Random implements java.io.Serializable {
private static final long serialVersionUID = 3905348978240129619L;
private long seed;
private double nextNextGaussian;
private boolean haveNextNextGaussian;
private transient Long saved_seed;
public Random() {
if (saved_seed == null) {
saved_seed = new Long(System.currentTimeMillis());
this.seed = (saved_seed.longValue() ^ 0x5DEECE66DL) & ((1L<<48) - 1);
}
setSeed(saved_seed.longValue());
}
public Random(long seed) {
setSeed(seed);
}
public void setSeed(long seed) {
this.seed = (seed ^ 0x5DEECE66DL) & ((1L<<48) - 1);
haveNextNextGaussian = false;
}
protected int next(int bits) {
seed = (seed * 0x5DEECE66DL + 0xBL) & ((1L << 48) - 1);
return (int)(seed >>> (48-bits));
}
public int nextInt() {
return next(32);
}
public int nextInt(int n) {
if (n<=0) {
throw new IllegalArgumentException("n must be positive");
}
if ((n & -n) == n) {// i.e., n is a power of 2
return (int)((n * (long)next(31)) >> 31);
}
int bits, val;
do {
bits = next(31);
val = bits % n;
} while(bits - val + (n-1) < 0);
return val;
}
public long nextLong() {
return ((long)next(32)<<32) + next(32);
}
public float nextFloat() {
return next(24) / ((float)(1<<24));
}
public double nextDouble() {
return (((long)next(26)<<27) + next(27)) / (double)(1L<<53);
}
public double nextGaussian(){
if (haveNextNextGaussian) {
haveNextNextGaussian = false;
return nextNextGaussian;
}
else {
double v1, v2, s;
do {
v1 = 2 * nextDouble() - 1;
v2 = 2 * nextDouble() - 1;
s = v1 * v1 + v2 * v2;
} while (s >= 1);
double norm = Math.sqrt(-2 * Math.log(s)/s);
nextNextGaussian = v2 * norm;
haveNextNextGaussian = true;
return v1 * norm;
}
}
public void nextBytes(byte [] buf){
for (int i=0; i < buf.length ; i++){
buf[i] = (byte)next(8);
}
}
public boolean nextBoolean() {
return next(1) != 0;
}
}