solidity/liblangutil/CharStream.h

/*
 * This file is part of solidity.
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 * 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
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 * * Redistributions of source code must retain the above copyright
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/**
 * @author Christian <c@ethdev.com>
 * @date 2014
 * Solidity scanner.
 */

#pragma once

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

namespace solidity::langutil
{

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

	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);
	/// Sets scanner position to @ _amount characters backwards in source text.
	/// @returns The character of the current location after update is returned.
	char rollback(size_t _amount);
	/// Sets scanner position to @ _location if it refers a valid offset in m_source.
	/// If not, nothing is done.
	/// @returns The character of the current location after update is returned.
	char setPosition(size_t _location);

	void reset() { m_position = 0; }

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

	///@{
	///@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;
	std::string m_name;
	size_t m_position{0};
};

}