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/*
Ousía
Copyright (C) 2014, 2015 Benjamin Paaßen, Andreas Stöckel
This program 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.
This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @file Reader.hpp
*
* Provides parsers for various micro formats. These formats include integers,
* doubles, strings, JSON and the Ousía struct notation.
*
* @author Andreas Stöckel (astoecke@techfak.uni-bielefeld.de)
*/
#ifndef _OUSIA_VARIANT_READER_HPP_
#define _OUSIA_VARIANT_READER_HPP_
#include <unordered_set>
#include <utility>
#include <core/BufferedCharReader.hpp>
#include "Variant.hpp"
namespace ousia {
namespace variant {
class Reader {
public:
// TODO: Pass logger instance instead of using error codes?
/**
* The Err enum describes possible error codes that may be encountered when
* parsing the microtypes.
*/
enum class Err : int {
/**
* Reached the end of the stream, but expected more data.
*/
ERR_UNEXPECTED_END = -1,
/**
* The stream is malformed.
*/
ERR_MALFORMED = -2,
/**
* Unexpected character.
*/
ERR_UNEXPECTED_CHARACTER = -3,
/**
* Unterminated literal.
*/
ERR_UNTERMINATED = -4,
/**
* Invalid escape character.
*/
ERR_INVALID_ESCAPE = -5,
/**
* A value of the requested type was extracted successfully.
*/
OK = 0
};
/**
* Parses a string which may either be enclosed by " or ', unescapes
* entities in the string as specified for JavaScript.
*
* @param reader is a reference to the BufferedCharReader instance which is
* the source for the character data. The reader will be positioned after
* the terminating quote character or at the terminating delimiting
* character.
* @param delims is an optional set of delimiters after which parsing has to
* be stopped (the delimiters may occur inside the actual string, but not
* outside). If nullptr is given, no delimiter is used and a complete string
* is read.
*/
static std::pair<Err, std::string> parseString(
BufferedCharReader &reader,
const unordered_set<char> *delims = nullptr);
/**
* Extracts an unescaped string from the given buffered char reader
* instance. This function just reads text until one of the given delimiter
* characters is reached.
*
* @param reader is a reference to the BufferedCharReader instance which is
* the source for the character data. The reader will be positioned at the
* terminating delimiting character.
* @param delims is a set of characters which will terminate the string.
* These characters are not included in the result. May not be nullptr.
*/
static std::pair<Err, std::string> parseUnescapedString(
BufferedCharReader &reader, const unordered_set<char> *delims);
/**
* Tries to parse the most specific item from the given stream until one of
* the given delimiters is reached or a meaningful literal has been read.
* The resulting variant represents the value that has been read.
*
* @param reader is a reference to the BufferedCharReader instance which is
* the source for the character data. The reader will be positioned at the
* terminating delimiting character.
* @param delims is a set of characters which will terminate the string.
* These characters are not included in the result. May not be nullptr.
*/
static std::pair<Err, Variant> parseGeneric(
BufferedCharReader &reader, const unordered_set<char> *delims);
};
}
}
#endif /* _OUSIA_VARIANT_READER_HPP_ */
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