1/*
2 * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23package org.graalvm.compiler.graph;
24
25import java.util.Iterator;
26import java.util.NoSuchElementException;
27
28class NodeUsageIterator implements Iterator<Node> {
29
30    final Node node;
31    int index = -1;
32    Node current;
33
34    void advance() {
35        current = null;
36        index++;
37        if (index == 0) {
38            current = node.usage0;
39        } else if (index == 1) {
40            current = node.usage1;
41        } else {
42            int relativeIndex = index - Node.INLINE_USAGE_COUNT;
43            if (relativeIndex < node.extraUsagesCount) {
44                current = node.extraUsages[relativeIndex];
45            }
46        }
47    }
48
49    NodeUsageIterator(Node node) {
50        this.node = node;
51        advance();
52    }
53
54    @Override
55    public boolean hasNext() {
56        return current != null;
57    }
58
59    @Override
60    public Node next() {
61        Node result = current;
62        if (result == null) {
63            throw new NoSuchElementException();
64        }
65        advance();
66        return result;
67    }
68
69    @Override
70    public void remove() {
71        throw new UnsupportedOperationException();
72    }
73}
74