flutter_flutter/sky/engine/platform/text/TextBreakIterator.cpp

/*
 * (C) 1999 Lars Knoll (knoll@kde.org)
 * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
 * Copyright (C) 2007-2009 Torch Mobile, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#include "flutter/sky/engine/platform/text/TextBreakIterator.h"

namespace blink {

unsigned numGraphemeClusters(const String& string) {
  unsigned stringLength = string.length();

  if (!stringLength)
    return 0;

  // The only Latin-1 Extended Grapheme Cluster is CR LF
  if (string.is8Bit() && !string.contains('\r'))
    return stringLength;

  NonSharedCharacterBreakIterator it(string);
  if (!it)
    return stringLength;

  unsigned num = 0;
  while (it.next() != TextBreakDone)
    ++num;
  return num;
}

unsigned numCharactersInGraphemeClusters(const String& string,
                                         unsigned numGraphemeClusters) {
  unsigned stringLength = string.length();

  if (!stringLength)
    return 0;

  // The only Latin-1 Extended Grapheme Cluster is CR LF
  if (string.is8Bit() && !string.contains('\r'))
    return std::min(stringLength, numGraphemeClusters);

  NonSharedCharacterBreakIterator it(string);
  if (!it)
    return std::min(stringLength, numGraphemeClusters);

  for (unsigned i = 0; i < numGraphemeClusters; ++i) {
    if (it.next() == TextBreakDone)
      return stringLength;
  }
  return it.current();
}

}  // namespace blink