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/*
    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.h", 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
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    * Neither the name of Google Inc. nor the names of its
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    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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    OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
 * @author Christian <c@ethdev.com>
 * @date 2014
 * Solidity scanner.
 */

#pragma once

#include <cstdint>
#include <string>
#include <tuple>

namespace langutil
{

/**
 * Bidirectional stream of characters.
 *
 * This CharStream is used by lexical analyzers as the source.
 */
class CharStream
{
public:
    CharStream(): m_position(0) {}
    explicit CharStream(std::string const& _source): m_source(_source), m_position(0) {}

    int position() const { return m_position; }
    bool isPastEndOfInput(size_t _charsForward = 0) const { return (m_position + _charsForward) >= m_source.size(); }

    char get(size_t _charsForward = 0) const { return m_source[m_position + _charsForward]; }
    char advanceAndGet(size_t _chars = 1);
    char rollback(size_t _amount);

    void reset() { m_position = 0; }

    std::string const& source() const { return m_source; }

    ///@{
    ///@name Error printing helper functions
    /// Functions that help pretty-printing parse errors
    /// Do only use in error cases, they are quite expensive.
    std::string lineAtPosition(int _position) const;
    std::tuple<int, int> translatePositionToLineColumn(int _position) const;
    ///@}

private:
    std::string m_source;
    size_t m_position;
};

}