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Common Lisp implementation running on the JVM
/*
* RandomState.java
*
* Copyright (C) 2003-2005 Peter Graves
* $Id$
*
* This program 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
* of the License, or (at your option) any later version.
*
* This program 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; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* 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.
*/
package org.armedbear.lisp;
import static org.armedbear.lisp.Lisp.*;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.math.BigInteger;
import java.util.Random;
public final class RandomState extends LispObject
{
private Random random;
public RandomState()
{
random = new Random();
}
public RandomState(RandomState rs)
{
try {
ByteArrayOutputStream byteOut = new ByteArrayOutputStream();
ObjectOutputStream out = new ObjectOutputStream(byteOut);
out.writeObject(rs.random);
out.close();
ByteArrayInputStream byteIn = new ByteArrayInputStream(byteOut.toByteArray());
ObjectInputStream in = new ObjectInputStream(byteIn);
random = (Random) in.readObject();
in.close();
}
catch (Throwable t) { // ANY exception gets converted to a lisp error
error(new LispError("Unable to copy random state."));
}
}
@Override
public LispObject typeOf()
{
return Symbol.RANDOM_STATE;
}
@Override
public LispObject classOf()
{
return BuiltInClass.RANDOM_STATE;
}
@Override
public LispObject typep(LispObject type)
{
if (type == Symbol.RANDOM_STATE)
return T;
if (type == BuiltInClass.RANDOM_STATE)
return T;
return super.typep(type);
}
@Override
public String printObject()
{
return unreadableString("RANDOM-STATE");
}
public LispObject random(LispObject arg)
{
if (arg instanceof Fixnum) {
int limit = ((Fixnum)arg).value;
if (limit > 0) {
int n = random.nextInt((int)limit);
return Fixnum.getInstance(n);
}
} else if (arg instanceof Bignum) {
BigInteger limit = ((Bignum)arg).value;
if (limit.signum() > 0) {
int bitLength = limit.bitLength();
BigInteger rand = new BigInteger(bitLength + 1, random);
BigInteger remainder = rand.remainder(limit);
return number(remainder);
}
} else if (arg instanceof SingleFloat) {
float limit = ((SingleFloat)arg).value;
if (limit > 0) {
float rand = random.nextFloat();
return new SingleFloat(rand * limit);
}
} else if (arg instanceof DoubleFloat) {
double limit = ((DoubleFloat)arg).value;
if (limit > 0) {
double rand = random.nextDouble();
return new DoubleFloat(rand * limit);
}
}
return type_error(arg, list(Symbol.OR,
list(Symbol.INTEGER, Fixnum.ONE),
list(Symbol.FLOAT, list(Fixnum.ZERO))));
}
// ### random limit &optional random-state => random-number
private static final Primitive RANDOM =
new Primitive(Symbol.RANDOM, "limit &optional random-state")
{
@Override
public LispObject execute(LispObject arg)
{
RandomState randomState =
(RandomState) Symbol._RANDOM_STATE_.symbolValue();
return randomState.random(arg);
}
@Override
public LispObject execute(LispObject first, LispObject second)
{
if (second instanceof RandomState) {
RandomState randomState = (RandomState) second;
return randomState.random(first);
}
return type_error(first, Symbol.RANDOM_STATE);
}
};
// ### make-random-state &optional state
private static final Primitive MAKE_RANDOM_STATE =
new Primitive(Symbol.MAKE_RANDOM_STATE, "&optional state")
{
@Override
public LispObject execute()
{
return new RandomState((RandomState)Symbol._RANDOM_STATE_.symbolValue());
}
@Override
public LispObject execute(LispObject arg)
{
if (arg == NIL)
return new RandomState((RandomState)Symbol._RANDOM_STATE_.symbolValue());
if (arg == T)
return new RandomState();
if (arg instanceof RandomState)
return new RandomState((RandomState)arg);
return type_error(arg, Symbol.RANDOM_STATE);
}
};
// ### random-state-p
private static final Primitive RANDOM_STATE_P =
new Primitive(Symbol.RANDOM_STATE_P, "object")
{
@Override
public LispObject execute(LispObject arg)
{
return arg instanceof RandomState ? T : NIL;
}
};
}