source: XMLIO_V2/external/include/Poco/DateTime.h @ 80

//
// DateTime.h
//
// $Id: //poco/1.3/Foundation/include/Poco/DateTime.h#3 $
//
// 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.
        ///
        /// The date and time stored in a DateTime is always in UTC
        /// (Coordinated Universal Time) and thus independent of the 
        /// timezone in effect on the system.
        ///
        /// 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