com.fasteasytrade.jrandtest.algo.MT19937 Maven / Gradle / Ivy
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/*
* Created on 16/02/2005
*
* JRandTest package
*
* Copyright (c) 2005, Zur Aougav, [email protected]
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* Redistributions of source code must retain the above copyright notice, this list
* of conditions and the following disclaimer.
*
* 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.
*
* Neither the name of the JRandTest nor the names of its contributors may be
* used to endorse or promote products derived from this software without specific
* prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 THE COPYRIGHT OWNER OR 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, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package com.fasteasytrade.jrandtest.algo;
import com.fasteasytrade.jrandtest.io.FileAlgoRandomStream;
/**
* Stream of random bytes from MT19937Prng class
*
*
* @author Zur Aougav
*/
public class MT19937 extends FileAlgoRandomStream {
MT19937Prng mt = null; // actual class algorithm
long[] defaultPublicKey = { 0x123, 0x234, 0x345, 0x456 };
byte[] outAlgoBuffer = new byte[4];
int outAlgoBufferIx = outAlgoBuffer.length;
public MT19937() {
super();
}
public MT19937(String keyFileName) {
super(keyFileName);
}
@Override
public String getFilename() {
return filename;
}
@Override
public void setFilename(String s) {
filename = s;
}
@Override
public void setupKeys() {
publicKeyLength = 256;
privateKeyLength = 256;
super.setupKeys();
}
@Override
public void setup() {
mt = new MT19937Prng();
if (publicKey == null || publicKey.length < 4) {
mt.init_by_array(defaultPublicKey, defaultPublicKey.length);
} else {
long[] p = new long[publicKey.length / 4];
for (int i = 0; i < p.length; i++) {
p[i] = 0xff & publicKey[4 * i];
p[i] = (p[i] << 8) | (0xff & publicKey[4 * i + 1]);
p[i] = (p[i] << 8) | (0xff & publicKey[4 * i + 2]);
p[i] = (p[i] << 8) | (0xff & publicKey[4 * i + 3]);
}
mt.init_by_array(p, p.length);
}
}
@Override
public boolean openInputStream() {
setup(); // make sure algorithm and keys/states are reset
if (filename != null) {
super.openInputStream();
}
count = 0;
countLastRead = SIZE;
actualSize = SIZE;
outAlgoBufferIx = outAlgoBuffer.length;
open = true;
return open;
}
@Override
public byte readByte() {
if (!isOpen()) {
return -1;
}
if (filename == null && count > maxCount) {
open = false;
return -1;
}
if (outAlgoBufferIx == outAlgoBuffer.length) {
int i = (int)mt.genrand_int32();
outAlgoBuffer[0] = (byte)(i >>> 24);
outAlgoBuffer[1] = (byte)(i >>> 16);
outAlgoBuffer[2] = (byte)(i >>> 8);
outAlgoBuffer[3] = (byte)i;
outAlgoBufferIx = 0;
}
byte prng = outAlgoBuffer[outAlgoBufferIx++];
if (filename == null) {
count++;
return prng;
}
/*
* we have a real filename to encrypt
*/
byte data = super.readByte();
return (byte)(prng ^ data);
}
@Override
public int readInt() {
if (!isOpen()) {
return -1;
}
if (filename == null && count > maxCount) {
open = false;
return -1;
}
int prng = 0;
if (outAlgoBufferIx == outAlgoBuffer.length) {
prng = (int)mt.genrand_int32();
if (filename == null) {
count += 4;
}
} else {
byte temp;
for (int i = 0; i < 4; i++) {
temp = readByte();
prng = (prng << 8) | (0xff & temp);
}
}
if (filename == null) {
return prng;
}
/*
* we have a real filename to encrypt
*/
int data = super.readInt();
return data ^ prng;
}
@Override
public long readLong() {
if (!isOpen()) {
return -1;
}
if (filename == null && count > maxCount) {
open = false;
return -1;
}
long prng = 0;
if (outAlgoBufferIx == outAlgoBuffer.length) {
prng = 0xffffffffL & mt.genrand_int32();
prng = (prng << 32) | (0xffffffffL & mt.genrand_int32());
if (filename == null) {
count += 8;
}
} else {
byte temp;
for (int i = 0; i < 8; i++) {
temp = readByte();
prng = (prng << 8) | (0xff & temp);
}
}
if (filename == null) {
return prng;
}
/*
* we have a real filename to encrypt
*/
long data = super.readLong();
return data ^ prng;
}
}