package gnu.crypto.prng;
// ----------------------------------------------------------------------------
// Copyright (C) 2001, 2002, Free Software Foundation, Inc.
//
// This file is part of GNU Crypto.
//
// GNU Crypto is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2, or (at your option)
// any later version.
//
// GNU Crypto 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 for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; see the file COPYING. If not, write to the
//
// Free Software Foundation Inc.,
// 51 Franklin Street, Fifth Floor,
// Boston, MA 02110-1301
// USA
//
// Linking this library statically or dynamically with other modules is
// making a combined work based on this library. Thus, the terms and
// conditions of the GNU General Public License cover the whole
// combination.
//
// As a special exception, the copyright holders of this library give
// you permission to link this library with independent modules to
// produce an executable, regardless of the license terms of these
// independent modules, and to copy and distribute the resulting
// executable under terms of your choice, provided that you also meet,
// for each linked independent module, the terms and conditions of the
// license of that module. An independent module is a module which is
// not derived from or based on this library. If you modify this
// library, you may extend this exception to your version of the
// library, but you are not obligated to do so. If you do not wish to
// do so, delete this exception statement from your version.
// ----------------------------------------------------------------------------
import java.io.Serializable;
import java.util.Map;
/**
* <p>An abstract class to facilitate implementing PRNG algorithms.</p>
*
* Modified slightly by jrandom for I2P (removing unneeded exceptions)
* @version $Revision: 1.1 $
*/
public abstract class BasePRNGStandalone implements IRandomStandalone, Serializable {
// Constants and variables
// -------------------------------------------------------------------------
/** The canonical name prefix of the PRNG algorithm. */
protected final String name;
/** Indicate if this instance has already been initialised or not. */
protected volatile boolean initialised;
/** A temporary buffer to serve random bytes. */
protected volatile byte[] buffer;
/** The index into buffer of where the next byte will come from. */
protected int ndx;
// Constructor(s)
// -------------------------------------------------------------------------
/**
* <p>Trivial constructor for use by concrete subclasses.</p>
*
* @param name the canonical name of this instance.
*/
protected BasePRNGStandalone(String name) {
this.name = name;
buffer = new byte[0];
}
// Class methods
// -------------------------------------------------------------------------
// Instance methods
// -------------------------------------------------------------------------
// IRandomStandalone interface implementation ----------------------------------------
public String name() {
return name;
}
public void init(Map<String, byte[]> attributes) {
this.setup(attributes);
ndx = 0;
initialised = true;
}
public byte nextByte() throws IllegalStateException {//, LimitReachedException {
if (!initialised) {
throw new IllegalStateException();
}
return nextByteInternal();
}
public void nextBytes(byte[] out) throws IllegalStateException {//, LimitReachedException {
nextBytes(out, 0, out.length);
}
public void nextBytes(byte[] out, int offset, int length)
throws IllegalStateException //, LimitReachedException
{
if (!initialised)
throw new IllegalStateException("not initialized");
if (length == 0)
return;
if (offset < 0 || length < 0 || offset + length > out.length)
throw new ArrayIndexOutOfBoundsException("offset=" + offset + " length="
+ length + " limit=" + out.length);
if (buffer == null)
throw new IllegalStateException("Random is shut down - do you have a static ref?");
if (ndx >= buffer.length) {
fillBlock();
ndx = 0;
}
int count = 0;
while (count < length) {
int amount = Math.min(buffer.length - ndx, length - count);
System.arraycopy(buffer, ndx, out, offset+count, amount);
count += amount;
ndx += amount;
if (ndx >= buffer.length) {
fillBlock();
ndx = 0;
}
}
}
public void addRandomByte(byte b) {
throw new UnsupportedOperationException("random state is non-modifiable");
}
public void addRandomBytes(byte[] buffer) {
addRandomBytes(buffer, 0, buffer.length);
}
public void addRandomBytes(byte[] buffer, int offset, int length) {
throw new UnsupportedOperationException("random state is non-modifiable");
}
// Instance methods
// -------------------------------------------------------------------------
public boolean isInitialised() {
return initialised;
}
private byte nextByteInternal() {//throws LimitReachedException {
if (buffer == null)
throw new IllegalStateException("Random is shut down - do you have a static ref?");
if (ndx >= buffer.length) {
this.fillBlock();
ndx = 0;
}
return buffer[ndx++];
}
// abstract methods to implement by subclasses -----------------------------
@Override
public Object clone() throws CloneNotSupportedException
{
return super.clone();
}
public abstract void setup(Map<String, byte[]> attributes);
public abstract void fillBlock(); //throws LimitReachedException;
}