001/*
002 * Copyright (c) 2014, 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;
024
025import java.util.*;
026
027/**
028 * Iterates over the nodes in a given graph.
029 */
030class GraphNodeIterator implements Iterator<Node> {
031
032    private final Graph graph;
033    private int index;
034
035    public GraphNodeIterator(Graph graph) {
036        this(graph, 0);
037    }
038
039    public GraphNodeIterator(Graph graph, int index) {
040        this.graph = graph;
041        this.index = index - 1;
042        forward();
043    }
044
045    private void forward() {
046        if (index < graph.nodesSize) {
047            do {
048                index++;
049            } while (index < graph.nodesSize && graph.nodes[index] == null);
050        }
051    }
052
053    @Override
054    public boolean hasNext() {
055        checkForDeletedNode();
056        return index < graph.nodesSize;
057    }
058
059    private void checkForDeletedNode() {
060        while (index < graph.nodesSize && graph.nodes[index] == null) {
061            index++;
062        }
063    }
064
065    @Override
066    public Node next() {
067        try {
068            return graph.nodes[index];
069        } finally {
070            forward();
071        }
072    }
073
074    @Override
075    public void remove() {
076        throw new UnsupportedOperationException();
077    }
078}