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
027class NodeUsageIterator implements Iterator<Node> {
028
029    final Node node;
030    int index = -1;
031    Node current;
032
033    void advance() {
034        current = null;
035        index++;
036        if (index == 0) {
037            current = node.usage0;
038        } else if (index == 1) {
039            current = node.usage1;
040        } else {
041            int relativeIndex = index - Node.INLINE_USAGE_COUNT;
042            if (relativeIndex < node.extraUsagesCount) {
043                current = node.extraUsages[relativeIndex];
044            }
045        }
046    }
047
048    public NodeUsageIterator(Node node) {
049        this.node = node;
050        advance();
051    }
052
053    public boolean hasNext() {
054        return current != null;
055    }
056
057    public Node next() {
058        Node result = current;
059        if (result == null) {
060            throw new NoSuchElementException();
061        }
062        advance();
063        return result;
064    }
065
066    @Override
067    public void remove() {
068        throw new UnsupportedOperationException();
069    }
070}