third_party/WebKit/Source/wtf/text/TextPosition.cpp

/*
 * Copyright (C) 2013, Google Inc. All rights reserved.
 *
 * 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 INC. AND ITS CONTRIBUTORS ``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 INC. OR ITS 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
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 */

#include "wtf/text/TextPosition.h"

#include "wtf/PtrUtil.h"
#include "wtf/StdLibExtras.h"
#include <algorithm>
#include <memory>

namespace WTF {

std::unique_ptr<Vector<unsigned>> lineEndings(const String& text) {
  std::unique_ptr<Vector<unsigned>> result(wrapUnique(new Vector<unsigned>()));

  unsigned start = 0;
  while (start < text.length()) {
    size_t lineEnd = text.find('\n', start);
    if (lineEnd == kNotFound)
      break;

    result->append(static_cast<unsigned>(lineEnd));
    start = lineEnd + 1;
  }
  result->append(text.length());

  return result;
}

OrdinalNumber TextPosition::toOffset(const Vector<unsigned>& lineEndings) {
  unsigned lineStartOffset = m_line != OrdinalNumber::first()
                                 ? lineEndings.at(m_line.zeroBasedInt() - 1) + 1
                                 : 0;
  return OrdinalNumber::fromZeroBasedInt(lineStartOffset +
                                         m_column.zeroBasedInt());
}

TextPosition TextPosition::fromOffsetAndLineEndings(
    unsigned offset,
    const Vector<unsigned>& lineEndings) {
  const unsigned* foundLineEnding =
      std::lower_bound(lineEndings.begin(), lineEndings.end(), offset);
  int lineIndex = foundLineEnding - &lineEndings.at(0);
  unsigned lineStartOffset =
      lineIndex > 0 ? lineEndings.at(lineIndex - 1) + 1 : 0;
  int column = offset - lineStartOffset;
  return TextPosition(OrdinalNumber::fromZeroBasedInt(lineIndex),
                      OrdinalNumber::fromZeroBasedInt(column));
}

}  // namespace WTF