/*
* logbitp.java
*
* Copyright (C) 2003 Peter Graves
* $Id: logbitp.java,v 1.6 2003/11/15 11:03:34 beedlem Exp $
*
* 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.
*/
package org.armedbear.lisp;
import java.math.BigInteger;
// ### logbitp
// logbitp index integer => generalized-boolean
public final class logbitp extends Primitive2
{
private logbitp(String name)
{
super(name);
}
public LispObject execute(LispObject first, LispObject second)
throws ConditionThrowable
{
int index = -1;
if (first instanceof Fixnum) {
index = ((Fixnum)first).getValue();
} else if (first instanceof Bignum) {
// FIXME If the number is really big, we're not checking the right
// bit...
if (((Bignum)first).getValue().signum() > 0)
index = Integer.MAX_VALUE;
}
if (index < 0)
throw new ConditionThrowable(new TypeError(first, "non-negative integer"));
BigInteger n;
if (second instanceof Fixnum)
n = ((Fixnum)second).getBigInteger();
else if (second instanceof Bignum)
n = ((Bignum)second).getValue();
else
throw new ConditionThrowable(new TypeError(second, "integer"));
// FIXME See above.
if (index == Integer.MAX_VALUE)
return n.signum() < 0 ? T : NIL;
return n.testBit(index) ? T : NIL;
}
private static final logbitp LOGBITP = new logbitp("logbitp");
}