third_party/WebKit/Source/core/editing/iterators/BackwardsCharacterIterator.cpp

/*
 * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012 Apple Inc. All
 * rights reserved.
 * Copyright (C) 2005 Alexey Proskuryakov.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "core/editing/iterators/BackwardsCharacterIterator.h"

namespace blink {

template <typename Strategy>
BackwardsCharacterIteratorAlgorithm<Strategy>::
    BackwardsCharacterIteratorAlgorithm(const PositionTemplate<Strategy>& start,
                                        const PositionTemplate<Strategy>& end,
                                        TextIteratorBehaviorFlags behavior)
    : m_offset(0),
      m_runOffset(0),
      m_atBreak(true),
      m_textIterator(start, end, behavior) {
  while (!atEnd() && !m_textIterator.length())
    m_textIterator.advance();
}

template <typename Strategy>
PositionTemplate<Strategy>
BackwardsCharacterIteratorAlgorithm<Strategy>::endPosition() const {
  if (!m_textIterator.atEnd()) {
    if (m_textIterator.length() > 1) {
      Node* n = m_textIterator.startContainer();
      return PositionTemplate<Strategy>::editingPositionOf(
          n, m_textIterator.endOffset() - m_runOffset);
    }
    DCHECK(!m_runOffset);
  }
  return m_textIterator.endPosition();
}

template <typename Strategy>
void BackwardsCharacterIteratorAlgorithm<Strategy>::advance(int count) {
  if (count <= 0) {
    DCHECK(!count);
    return;
  }

  m_atBreak = false;

  int remaining = m_textIterator.length() - m_runOffset;
  if (count < remaining) {
    m_runOffset += count;
    m_offset += count;
    return;
  }

  count -= remaining;
  m_offset += remaining;

  for (m_textIterator.advance(); !atEnd(); m_textIterator.advance()) {
    int runLength = m_textIterator.length();
    if (!runLength) {
      m_atBreak = true;
    } else {
      if (count < runLength) {
        m_runOffset = count;
        m_offset += count;
        return;
      }

      count -= runLength;
      m_offset += runLength;
    }
  }

  m_atBreak = true;
  m_runOffset = 0;
}

template class CORE_TEMPLATE_EXPORT
    BackwardsCharacterIteratorAlgorithm<EditingStrategy>;
template class CORE_TEMPLATE_EXPORT
    BackwardsCharacterIteratorAlgorithm<EditingInFlatTreeStrategy>;

}  // namespace blink