poco/Foundation/include/Poco/DateTimeParser.h

//
// DateTimeParser.h
//
// Library: Foundation
// Package: DateTime
// Module:  DateTimeParser
//
// Definition of the DateTimeParser class.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier:	BSL-1.0
//


#ifndef Foundation_DateTimeParser_INCLUDED
#define Foundation_DateTimeParser_INCLUDED


#include "Poco/Foundation.h"
#include "Poco/DateTime.h"


namespace Poco {


class Foundation_API DateTimeParser
	/// This class provides a method for parsing dates and times
	/// from strings. All parsing methods do their best to
	/// parse a meaningful result, even from malformed input
	/// strings.
	///
	/// The returned DateTime will always contain a time in the same
	/// timezone as the time in the string. Call DateTime::makeUTC()
	/// with the timeZoneDifferential returned by parse() to convert
	/// the DateTime to UTC.
	///
	/// Note: When parsing a time in 12-hour (AM/PM) format, the hour
	/// (%h) must be parsed before the AM/PM designator (%a, %A),
	/// otherwise the AM/PM designator will be ignored.
	///
	/// See the DateTimeFormatter class for a list of supported format specifiers.
	/// In addition to the format specifiers supported by DateTimeFormatter, an
	/// additional specifier is supported: %r will parse a year given by either
	/// two or four digits. Years 69-00 are interpreted in the 20th century
	/// (1969-2000), years 01-68 in the 21th century (2001-2068).
	///
	/// Note that in the current implementation all characters other than format specifiers in
	/// the format string are ignored/not matched against the date/time string. This may
	/// lead to non-error results even with nonsense input strings.
	/// This may change in a future version to a more strict behavior.
	/// If more strict format validation of date/time strings is required, a regular
	/// expression could be used for initial validation, before passing the string
	/// to DateTimeParser.
	/// TODO: Correct description

{
public:
	static void parse(const std::string& fmt, const std::string& str, DateTime& dateTime, int& timeZoneDifferential);
		/// Parses a date and time in the given format from the given string.
		/// Performs cleanup of the input string (trims spaces).
		/// Throws a SyntaxException if the string cannot be successfully parsed.
		/// Please see DateTimeFormatter::format() for a description of the format string.
		/// Class DateTimeFormat defines format strings for various standard date/time formats.

	static DateTime parse(const std::string& fmt, const std::string& str, int& timeZoneDifferential);
		/// Parses a date and time in the given format from the given string.
		/// Performs cleanup of the input string (trims spaces).
		/// Throws a SyntaxException if the string cannot be successfully parsed.
		/// Please see DateTimeFormatter::format() for a description of the format string.
		/// Class DateTimeFormat defines format strings for various standard date/time formats.

	static bool tryParse(const std::string& fmt, const std::string& str, DateTime& dateTime, int& timeZoneDifferential);
		/// Parses a date and time in the given format from the given string.
		/// Performs cleanup of the input string (trims spaces).
		/// Returns true if the string has been successfully parsed, false otherwise.
		/// Please see DateTimeFormatter::format() for a description of the format string.
		/// Class DateTimeFormat defines format strings for various standard date/time formats.

	static void parse(const std::string& str, DateTime& dateTime, int& timeZoneDifferential);
		/// Parses a date and time from the given dateTime string. Before parsing, the method
		/// performs cleanup of the input string (trims spaces) when cleanup is true and
		/// examines the dateTime string for a known date/time format.
		/// Throws a SyntaxException if the string cannot be successfully parsed.
		/// Please see DateTimeFormatter::format() for a description of the format string.
		/// Class DateTimeFormat defines format strings for various standard date/time formats.

	static DateTime parse(const std::string& str, int& timeZoneDifferential);
		/// Parses a date and time from the given dateTime string. Before parsing, the method
		/// performs cleanup of the input string (trims spaces) and
		/// examines the dateTime string for a known date/time format.
		/// Please see DateTimeFormatter::format() for a description of the format string.
		/// Class DateTimeFormat defines format strings for various standard date/time formats.

	static bool tryParse(const std::string& str, DateTime& dateTime, int& timeZoneDifferential);
		/// Parses a date and time from the given dateTime string. Before parsing, the method
		/// performs cleanup of the input string (trims spaces) and
		/// examines the dateTime string for a known date/time format.
		/// Please see DateTimeFormatter::format() for a description of the format string.
		/// Class DateTimeFormat defines format strings for various standard date/time formats.

	static int parseMonth(std::string::const_iterator& it, const std::string::const_iterator& end);
		/// Tries to interpret the given range as a month name. The range must be at least
		/// three characters long.
		/// Returns the month number (1 .. 12) if the month name is valid. Otherwise throws
		/// a SyntaxException.

	static int parseDayOfWeek(std::string::const_iterator& it, const std::string::const_iterator& end);
		/// Tries to interpret the given range as a weekday name. The range must be at least
		/// three characters long.
		/// Returns the weekday number (0 .. 6, where 0 = Sunday, 1 = Monday, etc.) if the
		/// weekday name is valid. Otherwise throws a SyntaxException.

protected:
	static int parseTZD(std::string::const_iterator& it, const std::string::const_iterator& end);
	static int parseAMPM(std::string::const_iterator& it, const std::string::const_iterator& end, int hour);
};


} // namespace Poco


#endif // Foundation_DateTimeParser_INCLUDED