1/*
2 * Copyright (C) 2007, 2008 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#ifndef PositionIterator_h
27#define PositionIterator_h
28
29#include "Node.h"
30#include "Position.h"
31
32namespace WebCore {
33
34// A Position iterator with constant-time
35// increment, decrement, and several predicates on the Position it is at.
36// Conversion to/from Position is O(n) in the offset.
37class PositionIterator {
38public:
39    PositionIterator()
40        : m_anchorNode(0)
41        , m_nodeAfterPositionInAnchor(0)
42        , m_offsetInAnchor(0)
43    {
44    }
45
46    PositionIterator(const Position& pos)
47        : m_anchorNode(pos.anchorNode())
48        , m_nodeAfterPositionInAnchor(m_anchorNode->childNode(pos.deprecatedEditingOffset()))
49        , m_offsetInAnchor(m_nodeAfterPositionInAnchor ? 0 : pos.deprecatedEditingOffset())
50    {
51    }
52    operator Position() const;
53
54    void increment();
55    void decrement();
56
57    Node* node() const { return m_anchorNode; }
58    int offsetInLeafNode() const { return m_offsetInAnchor; }
59    void setOffsetInLeafNode(int offset);
60
61    bool atStart() const;
62    bool atEnd() const;
63    bool atStartOfNode() const;
64    bool atEndOfNode() const;
65    bool isCandidate() const;
66
67private:
68    Node* m_anchorNode;
69    Node* m_nodeAfterPositionInAnchor; // If this is non-null, m_nodeAfterPositionInAnchor->parentNode() == m_anchorNode;
70    int m_offsetInAnchor;
71};
72
73} // namespace WebCore
74
75#endif // PositionIterator_h
76