/* Soot - a J*va Optimization Framework
 * Copyright (C) 2003 Ondrej Lhotak
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

package soot.util;

public final class SharedBitSet {
    BitVector value;
    boolean own = true;
    public SharedBitSet(int i) {
        value = new BitVector( i );
    }
    public SharedBitSet() {
        this(32);
    }
    private void acquire() {
        if( own ) return;
        own = true;
        value = (BitVector) value.clone();
    }
    private void canonicalize() {
        value = SharedBitSetCache.v().canonicalize( value );
        own = false;
    }
    public boolean set(int bit) {
        acquire();
        return value.set(bit);
    }
    public void clear(int bit) {
        acquire();
        value.clear(bit);
    }
    public boolean get(int bit) {
        return value.get(bit);
    }
    public void and( SharedBitSet other ) {
        if( own ) {
            value.and( other.value );
        } else {
            value = BitVector.and( value, other.value );
            own = true;
        }
        canonicalize();
    }
    public void or( SharedBitSet other ) {
        if( own ) {
            value.or( other.value );
        } else {
            value = BitVector.or( value, other.value );
            own = true;
        }
        canonicalize();
    }
    public boolean orAndAndNot( SharedBitSet orset, SharedBitSet andset, SharedBitSet andnotset ) {
        acquire();
        boolean ret = value.orAndAndNot( orset.value, andset.value, andnotset.value );
        canonicalize();
        return ret;
    }
    public boolean orAndAndNot( SharedBitSet orset, BitVector andset, SharedBitSet andnotset ) {
        acquire();
        boolean ret = value.orAndAndNot( orset.value, andset,
                andnotset == null ? null : andnotset.value );
        canonicalize();
        return ret;
    }
    public BitSetIterator iterator() {
        return value.iterator(); 
    }
    public String toString() {
        StringBuffer b = new StringBuffer();
        for( BitSetIterator it = iterator(); it.hasNext(); ) {
            b.append( it.next() );
            b.append( "," );
        }
        return b.toString();
    }
}