Community Core Vision (Beta)

//

// DateTime.h

//

// $Id: //poco/1.3/Foundation/include/Poco/DateTime.h#2 $

//

// Library: Foundation

// Package: DateTime

// Module:  DateTime

//

// Definition of the DateTime class.

//

// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.

// and Contributors.

//

// Permission is hereby granted, free of charge, to any person or organization

// obtaining a copy of the software and accompanying documentation covered by

// this license (the "Software") to use, reproduce, display, distribute,

// execute, and transmit the Software, and to prepare derivative works of the

// Software, and to permit third-parties to whom the Software is furnished to

// do so, all subject to the following:

// 

// The copyright notices in the Software and this entire statement, including

// the above license grant, this restriction and the following disclaimer,

// must be included in all copies of the Software, in whole or in part, and

// all derivative works of the Software, unless such copies or derivative

// works are solely in the form of machine-executable object code generated by

// a source language processor.

// 

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT

// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE

// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,

// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER

// DEALINGS IN THE SOFTWARE.

//

#ifndef Foundation_DateTime_INCLUDED

#define Foundation_DateTime_INCLUDED

#include "Poco/Foundation.h"

#include "Poco/Timestamp.h"

#include "Poco/Timespan.h"

namespace Poco {

class Foundation_API DateTime

        /// This class represents an instant in time, expressed

        /// in years, months, days, hours, minutes, seconds

        /// and milliseconds based on the Gregorian calendar.

        /// The class is mainly useful for conversions between

        /// UTC, Julian day and Gregorian calendar dates.

        ///

        /// Conversion calculations are based on algorithms

        /// collected and described by Peter Baum at

        /// http://vsg.cape.com/~pbaum/date/date0.htm

        ///

        /// Internally, this class stores a date/time in two

        /// forms (UTC and broken down) for performance reasons. Only use 

        /// this class for conversions between date/time representations.

        /// Use the Timestamp class for everything else.

        ///

        /// Notes:

        ///   * Zero is a valid year (in accordance with ISO 8601 and astronomical year numbering)

        ///   * Year zero (0) is a leap year

        ///   * Negative years (years preceding 1 BC) are not supported

        ///

        /// For more information, please see:

        ///   * http://en.wikipedia.org/wiki/Gregorian_Calendar

        ///   * http://en.wikipedia.org/wiki/Julian_day

        ///   * http://en.wikipedia.org/wiki/UTC

        ///   * http://en.wikipedia.org/wiki/ISO_8601

{

public:

        enum Months

                /// Symbolic names for month numbers (1 to 12).

        {

                JANUARY = 1,

                FEBRUARY,

                MARCH,

                APRIL,

                MAY,

                JUNE,

                JULY,

                AUGUST,

                SEPTEMBER,

                OCTOBER,

                NOVEMBER,

                DECEMBER

        };

        enum DaysOfWeek

                /// Symbolic names for week day numbers (0 to 6).

        {

                SUNDAY = 0,

                MONDAY,

                TUESDAY,

                WEDNESDAY,

                THURSDAY,

                FRIDAY,

                SATURDAY

        };

        DateTime();

                /// Creates a DateTime for the current date and time.

        DateTime(const Timestamp& timestamp);

                /// Creates a DateTime for the date and time given in

                /// a Timestamp.

        DateTime(int year, int month, int day, int hour = 0, int minute = 0, int second = 0, int millisecond = 0, int microsecond = 0);

                /// Creates a DateTime for the given Gregorian date and time.

                ///   * year is from 0 to 9999.

                ///   * month is from 1 to 12.

                ///   * day is from 1 to 31.

                ///   * hour is from 0 to 23.

                ///   * minute is from 0 to 59.

                ///   * second is from 0 to 59.

                ///   * millisecond is from 0 to 999.

                ///   * microsecond is from 0 to 999.

        DateTime(double julianDay);

                /// Creates a DateTime for the given Julian day.

        DateTime(Timestamp::UtcTimeVal utcTime, Timestamp::TimeDiff diff);

                /// Creates a DateTime from an UtcTimeVal and a TimeDiff.

                ///

                /// Mainly used internally by DateTime and friends.

        DateTime(const DateTime& dateTime);

                /// Copy constructor. Creates the DateTime from another one.

        ~DateTime();

                /// Destroys the DateTime.

        DateTime& operator = (const DateTime& dateTime);

                /// Assigns another DateTime.

        DateTime& operator = (const Timestamp& timestamp);

                /// Assigns a Timestamp.

        DateTime& operator = (double julianDay);

                /// Assigns a Julian day.

        DateTime& assign(int year, int month, int day, int hour = 0, int minute = 0, int second = 0, int millisecond = 0, int microseconds = 0);

                /// Assigns a Gregorian date and time.

                ///   * year is from 0 to 9999.

                ///   * month is from 1 to 12.

                ///   * day is from 1 to 31.

                ///   * hour is from 0 to 23.

                ///   * minute is from 0 to 59.

                ///   * second is from 0 to 59.

                ///   * millisecond is from 0 to 999.

                ///   * microsecond is from 0 to 999.

        void swap(DateTime& dateTime);

                /// Swaps the DateTime with another one.

        int year() const;

                /// Returns the year.

        int month() const;

                /// Returns the month (1 to 12).

        int week(int firstDayOfWeek = MONDAY) const;

                /// Returns the week number within the year.

                /// FirstDayOfWeek should be either SUNDAY (0) or MONDAY (1).

                /// The returned week number will be from 0 to 53. Week number 1 is the week 

                /// containing January 4. This is in accordance to ISO 8601.

                /// 

                /// The following example assumes that firstDayOfWeek is MONDAY. For 2005, which started

                /// on a Saturday, week 1 will be the week starting on Monday, January 3.

                /// January 1 and 2 will fall within week 0 (or the last week of the previous year).

                ///

                /// For 2007, which starts on a Monday, week 1 will be the week startung on Monday, January 1.

                /// There will be no week 0 in 2007.

        int day() const;

                /// Returns the day witin the month (1 to 31).

        int dayOfWeek() const;

                /// Returns the weekday (0 to 6, where

                /// 0 = Sunday, 1 = Monday, ..., 6 = Saturday).

        int dayOfYear() const;

                /// Returns the number of the day in the year.

                /// January 1 is 1, February 1 is 32, etc.

        int hour() const;

                /// Returns the hour (0 to 23).

        int hourAMPM() const;

                /// Returns the hour (0 to 12).

        bool isAM() const;

                /// Returns true if hour < 12;

        bool isPM() const;

                /// Returns true if hour >= 12.

        int minute() const;

                /// Returns the minute (0 to 59).

        int second() const;

                /// Returns the second (0 to 59).

        int millisecond() const;

                /// Returns the millisecond (0 to 999)

        int microsecond() const;

                /// Returns the microsecond (0 to 999)

        double julianDay() const;

                /// Returns the julian day for the date and time.

        Timestamp timestamp() const;

                /// Returns the date and time expressed as a Timestamp.

        Timestamp::UtcTimeVal utcTime() const;

                /// Returns the date and time expressed in UTC-based

                /// time. UTC base time is midnight, October 15, 1582.

                /// Resolution is 100 nanoseconds.

        bool operator == (const DateTime& dateTime) const;        

        bool operator != (const DateTime& dateTime) const;        

        bool operator <  (const DateTime& dateTime) const;        

        bool operator <= (const DateTime& dateTime) const;        

        bool operator >  (const DateTime& dateTime) const;        

        bool operator >= (const DateTime& dateTime) const;        

        DateTime  operator +  (const Timespan& span) const;

        DateTime  operator -  (const Timespan& span) const;

        Timespan  operator -  (const DateTime& dateTime) const;

        DateTime& operator += (const Timespan& span);

        DateTime& operator -= (const Timespan& span);

        void makeUTC(int tzd);

                /// Converts a local time into UTC, by applying the given time zone differential.

        void makeLocal(int tzd);

                /// Converts a UTC time into a local time, by applying the given time zone differential.

        static bool isLeapYear(int year);

                /// Returns true if the given year is a leap year;

                /// false otherwise.

        static int daysOfMonth(int year, int month);

                /// Returns the number of days in the given month

                /// and year. Month is from 1 to 12.

        static bool isValid(int year, int month, int day, int hour = 0, int minute = 0, int second = 0, int millisecond = 0, int microsecond = 0);

                /// Checks if the given date and time is valid

                /// (all arguments are within a proper range).

                ///

                /// Returns true if all arguments are valid, false otherwise.

protected:        

        static double toJulianDay(Timestamp::UtcTimeVal utcTime);

                /// Computes the Julian day for an UTC time.

        static double toJulianDay(int year, int month, int day, int hour = 0, int minute = 0, int second = 0, int millisecond = 0, int microsecond = 0);

                /// Computes the Julian day for a gregorian calendar date and time.

                /// See <http://vsg.cape.com/~pbaum/date/jdimp.htm>, section 2.3.1 for the algorithm.

        static Timestamp::UtcTimeVal toUtcTime(double julianDay);

                /// Computes the UTC time for a Julian day.

        void computeGregorian(double julianDay);

                /// Computes the Gregorian date for the given Julian day.

                /// See <http://vsg.cape.com/~pbaum/date/injdimp.htm>, section 3.3.1 for the algorithm.

        void computeDaytime();

                /// Extracts the daytime (hours, minutes, seconds, etc.) from the stored utcTime.

private:

        void checkLimit(short& lower, short& higher, short limit);

        void normalize();

                ///utility functions used to correct the overflow in computeGregorian

        Timestamp::UtcTimeVal _utcTime;

        short  _year;

        short  _month;

        short  _day;

        short  _hour;

        short  _minute;

        short  _second;

        short  _millisecond;

        short  _microsecond;

};

//

// inlines

//

inline Timestamp DateTime::timestamp() const

{

        return Timestamp::fromUtcTime(_utcTime);

}

inline Timestamp::UtcTimeVal DateTime::utcTime() const

{

        return _utcTime;

}

inline int DateTime::year() const

{

        return _year;

}

inline int DateTime::month() const

{

        return _month;

}

inline int DateTime::day() const

{

        return _day;

}

inline int DateTime::hour() const

{

        return _hour;

}

inline int DateTime::hourAMPM() const

{

        if (_hour < 1)

                return 12;

        else if (_hour > 12)

                return _hour - 12;

        else

                return _hour;

}

inline bool DateTime::isAM() const

{

        return _hour < 12;

}

inline bool DateTime::isPM() const

{

        return _hour >= 12;

}

inline int DateTime::minute() const

{

        return _minute;

}

inline int DateTime::second() const

{

        return _second;

}

inline int DateTime::millisecond() const

{

        return _millisecond;

}

inline int DateTime::microsecond() const

{

        return _microsecond;

}

inline bool DateTime::operator == (const DateTime& dateTime) const

{

        return _utcTime == dateTime._utcTime;

}

inline bool DateTime::operator != (const DateTime& dateTime) const        

{

        return _utcTime != dateTime._utcTime;

}

inline bool DateTime::operator <  (const DateTime& dateTime) const        

{

        return _utcTime < dateTime._utcTime;

}

inline bool DateTime::operator <= (const DateTime& dateTime) const

{

        return _utcTime <= dateTime._utcTime;

}

inline bool DateTime::operator >  (const DateTime& dateTime) const

{

        return _utcTime > dateTime._utcTime;

}

inline bool DateTime::operator >= (const DateTime& dateTime) const        

{

        return _utcTime >= dateTime._utcTime;

}

inline bool DateTime::isLeapYear(int year)

{

        return (year % 4) == 0 && ((year % 100) != 0 || (year % 400) == 0);

}

inline void swap(DateTime& d1, DateTime& d2)

{

        d1.swap(d2);

}

} // namespace Poco

#endif // Foundation_DateTime_INCLUDED