001/*
002 * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.
003 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004 *
005 * This code is free software; you can redistribute it and/or modify it
006 * under the terms of the GNU General Public License version 2 only, as
007 * published by the Free Software Foundation.
008 *
009 * This code is distributed in the hope that it will be useful, but WITHOUT
010 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
011 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
012 * version 2 for more details (a copy is included in the LICENSE file that
013 * accompanied this code).
014 *
015 * You should have received a copy of the GNU General Public License version
016 * 2 along with this work; if not, write to the Free Software Foundation,
017 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
018 *
019 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
020 * or visit www.oracle.com if you need additional information or have any
021 * questions.
022 */
023package com.oracle.graal.graph.iterators;
024
025import java.util.*;
026
027import com.oracle.graal.graph.*;
028
029public class DistinctPredicatedProxyNodeIterator<T extends Node> extends PredicatedProxyNodeIterator<T> {
030
031    private NodeBitMap visited;
032
033    public DistinctPredicatedProxyNodeIterator(Iterator<T> iterator, NodePredicate predicate) {
034        super(iterator, predicate);
035    }
036
037    @Override
038    protected void forward() {
039        if (current == null) {
040            super.forward();
041            while (!accept(current)) {
042                current = null;
043                super.forward();
044            }
045        }
046    }
047
048    private boolean accept(T n) {
049        if (n == null) {
050            return true;
051        }
052        if (visited == null) {
053            visited = n.graph().createNodeBitMap();
054        }
055        boolean accept = !visited.isMarked(n);
056        visited.mark(n);
057        return accept;
058    }
059}