WebCore/PositionIterator.h

   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
  32 namespace 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.
  37 class PositionIterator {
  38 public:
  39     PositionIterator()
  40         : m_parent(0)
  41         , m_child(0)
  42         , m_offset(0)
  43     {
  44     }
  45
  46     PositionIterator(const Position& pos)
  47         : m_parent(pos.node())
  48         , m_child(m_parent->childNode(pos.offset()))
  49         , m_offset(m_child ? 0 : pos.offset())
  50     {
  51     }
  52     operator Position() const;
  53
  54     void increment();
  55     void decrement();
  56
  57     Node* node() const { return m_parent; }
  58     int offsetInLeafNode() const { return m_offset; }
  59
  60     bool atStart() const;
  61     bool atEnd() const;
  62     bool atStartOfNode() const;
  63     bool atEndOfNode() const;
  64     bool isCandidate() const;
  65
  66 private:
  67     Node* m_parent;
  68     Node* m_child;
  69     int m_offset;
  70 };
  71
  72 } // namespace WebCore
  73
  74 #endif // PositionIterator_h