CSVReader.hpp
No OneTemporary
Actions

Size

9 KB

Referenced Files

None

Subscribers

None

CSVReader.hpp
View Options

	//===-- rosa/support/csv/CSVReader.hpp --------------------------- C++ --===//
	//
	// The RoSA Framework
	//
	//===----------------------------------------------------------------------===//
	///
	/// \file rosa/support/csv/CSVReader.hpp
	///
	/// \authors David Juhasz (david.juhasz@tuwien.ac.at), Edwin Willegger (edwin.willegger@tuwien.ac.at)
	///
	/// \date 2017-2019
	///
	/// \brief Facitilities to read CSV files.
	///
	/// \note The implementation is based on the solution at
	/// https://stackoverflow.com/a/1120224
	///
	//===----------------------------------------------------------------------===//

	#ifndef ROSA_SUPPORT_CSV_CSVREADER_HPP
	#define ROSA_SUPPORT_CSV_CSVREADER_HPP

	#include "rosa/support/debug.hpp"
	#include "rosa/support/sequence.hpp"

	#include <istream>
	#include <sstream>
	#include <vector>
	#include <map>
	#include <algorithm>
	#include <set>

	namespace rosa {
	namespace csv {

	/// Indicating it the CSV file contains any header or not
	enum class HeaderInformation {
	HasHeader,
	HasNoHeader
	};

	/// Anonymous namespace providing implementation details for
	/// \c rosa::csv::CSVIterator, consider it private.
	namespace {

	/// Provides facility for parsing one value from a string.
	///
	/// \tparam T type of value to parse
	/// \tparam IsSignedInt if \p T is a signed integral type, always use default
	/// \tparam IsUnsignedInt if \p T is an unsigned integral type, always use
	/// default
	/// \tparam IsFloat if \p T is a floating-point type, always use default
	/// \tparam IsString if \p T is \c std::string, always use default
	///
	/// \note Specializations of this struct are provided for arithmentic types
	/// and \c std::string.
	template <typename T,
	bool IsSignedInt =
	(std::is_integral<T>::value && std::is_signed<T>::value),
	bool IsUnsignedInt =
	(std::is_integral<T>::value && std::is_unsigned<T>::value),
	bool IsFloat = std::is_floating_point<T>::value,
	bool IsString = std::is_same<T, std::string>::value>
	struct ValueParser {

	///
	///
	/// \param Cell the \c std::string to parse
	///
	/// \return the parsed value
	///
	/// \note The function silently fails if cannot parse \p Cell for type \p T.
	static T parse(const std::string &Cell) noexcept;
	};

	template <typename T>
	struct ValueParser<T, true, false, false, false> {
	STATIC_ASSERT((std::is_integral<T>::value && std::is_signed<T>::value),
	"wrong type"); // Sanity check.
	static T parse(const std::string &Cell) noexcept {
	return static_cast<T>(std::stoll(Cell));
	}
	};

	template <typename T>
	struct ValueParser<T, false, true, false, false> {
	STATIC_ASSERT((std::is_integral<T>::value && std::is_unsigned<T>::value),
	"wrong type"); // Sanity check.
	static T parse(const std::string &Cell) noexcept {
	return static_cast<T>(std::stoull(Cell));
	}
	};

	template <typename T>
	struct ValueParser<T, false, false, true, false> {
	STATIC_ASSERT((std::is_floating_point<T>::value),
	"wrong type"); // Sanity check.
	static T parse(const std::string &Cell) noexcept {
	return static_cast<T>(std::stold(Cell));
	}
	};

	template <typename T>
	struct ValueParser<T, false, false, false, true> {
	STATIC_ASSERT((std::is_same<T, std::string>::value),
	"wrong type"); // Sanity check.
	static T parse(const std::string &Cell) noexcept { return Cell; }
	};

	/// Parses and stores entries from a row of CSV data.
	///
	/// \tparam Ts types of values to parse and store, i.e. entries in the row
	///
	/// \note The implementation relies on \c rosa::csv::CSVRowParser, which is
	/// implemented only for `arithmetic` types -- signed and unsigned integral
	/// and floating-point types -- and for \c std::string. Those are the valid
	/// values for \p Ts.
	template <typename... Ts> class CSVRow {
	private:
	/// Parses a given row of CSV data into \c CSVRow::Data.
	///
	/// \ CSVRow::Data is filled with values parsed from \p LineStream. Entries
	/// in the line are to be separated by commas, the character `,`.
	///
	/// \note Parsed values are silently converted to types \p Ts.
	///
	/// \note Parsing silently fails if values do not match \p Ts.
	///
	/// \tparam S0 indices to access tuple elements.
	///
	/// \param [in,out] LineStream the line to parse
	///
	/// \note The last argument is used only to get \p S0, the actual value of
	/// the parameter is ignored.
	template <size_t... S0>
	void parseRow(std::stringstream &LineStream, Seq<S0...>) {
	STATIC_ASSERT(sizeof...(Ts) == sizeof...(S0),
	"Not matching template arguments.");
	std::string Cell;
	// Get fields and parse the values into the proper element of the tuple
	// one by one in a fold expression.
	((std::getline(LineStream, Cell, ','),
	std::get<S0>(Data) = ValueParser<Ts>::parse(Cell)),
	...);
	}

	public:
	/// Parses and stores one row of CSV data.
	///
	/// The function reads one line from \p Str and parses it into
	/// \c rosa::csv::CSVRow::Data using \c rosa::csv::CSVRowParser.
	///
	/// \param [in,out] Str input stream of a CSV file
	void readNextRow(std::istream &Str) {
	std::string Line;
	std::getline(Str, Line);
	std::stringstream LineStream(Line);
	parseRow(LineStream, seq_t<sizeof...(Ts)>());
	}

	/// Gives a constant references for the \c std::tuple containing the values
	/// read by \p this object.
	///
	/// \return \c CSVRow::Data
	const std::tuple<Ts...> &tuple(void) const noexcept { return Data; }

	private:
	std::tuple<Ts...> Data; ///< Stores parsed entries
	};

	/// Reads a row of CSV data into \c rosa::csv::CSVRow.
	///
	/// The next line is read from \p Str by calling
	/// \c rosa::csv::CSVRow::readNextRow on \p Data.
	///
	/// \tparam Ts type of values to read from the row
	///
	/// \note The CSV file should contain a line with fields matching \p Ts...
	///
	/// \param [in,out] Str input stream of a CSV file
	/// \param [in,out] Data object to read the next line into
	///
	/// \return \p Str after reading one line from it
	template <typename... Ts>
	std::istream &operator>>(std::istream &Str, CSVRow<Ts...> &Data) {
	Data.readNextRow(Str);
	return Str;
	}

	} // End namespace

	/// Provides `InputIterator` features for iterating over a CSV file.
	///
	/// The iterator parses rows into `std::tuple` values and iterates over the
	/// file row by row.
	///
	/// \tparam Ts types of values stored in one row of the CSV file
	///
	/// \note The iterator expects each row to consists of fields matching \p Ts.
	///
	/// \note The implementation relies on \c rosa::csv::CSVRow, which in turn
	/// relies on \c rosa::csv::CSVRowParser, which is implemented only for
	/// `arithmetic` types -- signed and unsigned integral types and floating-point
	/// types -- and for \c std::string. Those are the valid values for \p Ts
	template <typename... Ts> class CSVIterator {
	public:
	/// \defgroup CSVIteratorTypedefs Typedefs of rosa::csv::CSVIterator
	///
	/// Standard `typedef`s for iterators.
	///
	///@{
	typedef std::input_iterator_tag
	iterator_category; ///< Category of the iterator.
	typedef std::tuple<Ts...> value_type; ///< Type of values iterated over.
	typedef std::size_t difference_type; ///< Type to identify distance.
	typedef std::tuple<Ts...> *pointer; ///< Pointer to the type iterated over.
	typedef std::tuple<Ts...>
	&reference; ///< Reference to the type iterated over.
	///@}

	/// Creates a new instance.
	///
	/// \param [in,out] S input stream to iterate over
	CSVIterator(std::istream &S) : Str(S.good() ? &S : nullptr), Row() {
	// \c rosa::csv::CSVIterator::Row is initialized empty so the first
	// incrementation here will read the first row.
	++(*this);
	}

	/// Creates an empty new instance.
	CSVIterator(void) noexcept : Str(nullptr) {}

	/// Pre-increment operator.
	///
	/// The implementation reads the next row. If the end of the input stream is
	/// reached, the operator becomes empty and has no further effect.
	///
	/// \return \p this object after incrementing it.
	CSVIterator &operator++() {
	if (Str) {
	if (!((*Str) >> Row)) {
	Str = nullptr;
	}
	}
	return *this;
	}

	/// Post-increment operator.
	///
	/// The implementation uses the pre-increment operator and returns a copy of
	/// the original state of \p this object.
	///
	/// \return \p this object before incrementing it.
	CSVIterator operator++(int) {
	CSVIterator Tmp(*this);
	++(*this);
	return Tmp;
	}

	/// Returns a constant reference to the current entry.
	///
	/// \note Should not dereference the iterator when it is empty.
	///
	/// \return constant reference to the current entry.
	const std::tuple<Ts...> &operator*(void)const noexcept { return Row.tuple(); }

	/// Returns a constant pointer to the current entry.
	///
	/// \note Should not dereference the iterator when it is empty.
	///
	/// \return constant pointer to the current entry.
	const std::tuple<Ts...> *operator->(void)const noexcept {
	return &Row.tuple();
	}

	/// Tells if \p this object is equal to another one.
	///
	/// Two \c rosa::csv::CSVReader instances are equal if and only if they are
	/// the same or both are empty.
	///
	/// \param RHS other object to compare to
	///
	/// \return whether \p this object is equal with \p RHS
	bool operator==(const CSVIterator &RHS) const noexcept {
	return ((this == &RHS) \|\| ((this->Str == nullptr) && (RHS.Str == nullptr)));
	}

	/// Tells if \p this object is not equal to another one.
	///
	/// \see rosa::csv::CSVReader::operator==
	///
	/// \param RHS other object to compare to
	///
	/// \return whether \p this object is not equal with \p RHS.
	bool operator!=(const CSVIterator &RHS) const noexcept {
	return !((*this) == RHS);
	}

	private:
	std::istream *Str; ///< Input stream of a CSV file to iterate over.
	CSVRow<Ts...> Row; ///< Content of the current row.
	};

	} // End namespace csv
	} // End namespace rosa

	#endif // ROSA_SUPPORT_CSV_CSVREADER_HPP

File Metadata

Mime Type: text/x-c++
Expires: Sat, Aug 29, 1:16 PM (4 h, 49 m)
Storage Engine: blob
Storage Format: Raw Data
Storage Handle: 376178
Default Alt Text: CSVReader.hpp (9 KB)

CSVReader.hppNo OneTemporaryActions

CSVReader.hppView Options

File Metadata

Event Timeline

CSVReader.hpp
No OneTemporary
Actions

CSVReader.hpp
View Options