/*

 * This file is part of solidity.

 *

 * solidity is free software: you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation, either version 3 of the License, or

 * (at your option) any later version.

 *

 * solidity 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 General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with solidity.  If not, see <http://www.gnu.org/licenses/>.

 *

 * This file is derived from the file "scanner.cc", which was part of the

 * V8 project. The original copyright header follows:

 *

 * Copyright 2006-2012, the V8 project authors. All rights reserved.

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are

 * met:

 *

 * * Redistributions of source code must retain the above copyright

 *   notice, this list of conditions and the following disclaimer.

 * * 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.

 * * Neither the name of Google Inc. nor the names of its

 *   contributors may be used to endorse or promote products derived

 *   from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 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 THE COPYRIGHT

 * OWNER 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.

*/

/**

 * Character stream / input file.

 */

#include <liblangutil/CharStream.h>

#include <liblangutil/Exceptions.h>

using namespace std;

using namespace solidity;

using namespace solidity::langutil;

char CharStream::advanceAndGet(size_t _chars)

{

  if (isPastEndOfInput())

    return 0;

  m_position += _chars;

  if (isPastEndOfInput())

    return 0;

  return m_source[m_position];

}

char CharStream::rollback(size_t _amount)

{

  solAssert(m_position >= _amount, "");

  m_position -= _amount;

  return get();

}

char CharStream::setPosition(size_t _location)

{

  solAssert(_location <= m_source.size(), "Attempting to set position past end of source.");

  m_position = _location;

  return get();

}

string CharStream::lineAtPosition(int _position) const

{

  // if _position points to \n, it returns the line before the \n

  using size_type = string::size_type;

  size_type searchStart = min<size_type>(m_source.size(), size_type(_position));

  if (searchStart > 0)

    searchStart--;

  size_type lineStart = m_source.rfind('\n', searchStart);

  if (lineStart == string::npos)

    lineStart = 0;

  else

    lineStart++;

  string line = m_source.substr(

    lineStart,

    min(m_source.find('\n', lineStart), m_source.size()) - lineStart

  );

  if (!line.empty() && line.back() == '\r')

    line.pop_back();

  return line;

}

LineColumn CharStream::translatePositionToLineColumn(int _position) const

{

  using size_type = string::size_type;

  using diff_type = string::difference_type;

  size_type searchPosition = min<size_type>(m_source.size(), size_type(_position));

  int lineNumber = static_cast<int>(count(m_source.begin(), m_source.begin() + diff_type(searchPosition), '\n'));

  size_type lineStart;

  if (searchPosition == 0)

    lineStart = 0;

  else

  {

    lineStart = m_source.rfind('\n', searchPosition - 1);

    lineStart = lineStart == string::npos ? 0 : lineStart + 1;

  }

  return LineColumn{lineNumber, static_cast<int>(searchPosition - lineStart)};

}

string_view CharStream::text(SourceLocation const& _location) const

{

  if (!_location.hasText())

    return {};

  solAssert(_location.sourceName && *_location.sourceName == m_name, "");

  solAssert(static_cast<size_t>(_location.end) <= m_source.size(), "");

  return string_view{m_source}.substr(

    static_cast<size_t>(_location.start),

    static_cast<size_t>(_location.end - _location.start)

  );

}

string CharStream::singleLineSnippet(string const& _sourceCode, SourceLocation const& _location)

{

  if (!_location.hasText())

    return {};

  if (static_cast<size_t>(_location.start) >= _sourceCode.size())

    return {};

  string cut = _sourceCode.substr(static_cast<size_t>(_location.start), static_cast<size_t>(_location.end - _location.start));

  auto newLinePos = cut.find_first_of("\n\r");

  if (newLinePos != string::npos)

    cut = cut.substr(0, newLinePos) + "...";

  return cut;

}

optional<int> CharStream::translateLineColumnToPosition(LineColumn const& _lineColumn) const

{

  return translateLineColumnToPosition(m_source, _lineColumn);

}

optional<int> CharStream::translateLineColumnToPosition(std::string const& _text, LineColumn const& _input)

{

  if (_input.line < 0)

    return nullopt;

  size_t offset = 0;

  for (int i = 0; i < _input.line; i++)

  {

    offset = _text.find('\n', offset);

    if (offset == _text.npos)

      return nullopt;

    offset++; // Skip linefeed.

  }

  size_t endOfLine = _text.find('\n', offset);

  if (endOfLine == string::npos)

    endOfLine = _text.size();

  if (offset + static_cast<size_t>(_input.column) > endOfLine)

    return nullopt;

  return offset + static_cast<size_t>(_input.column);

}