poco/Foundation/include/Poco/DateTime.h

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//
// DateTime.h
//
// $Id: //poco/1.4/Foundation/include/Poco/DateTime.h#1 $
//
// Library: Foundation
// Package: DateTime
// Module: DateTime
//
// Definition of the DateTime class.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier: BSL-1.0
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//
#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).
///
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/// For 2007, which starts on a Monday, week 1 will be the week starting on Monday, January 1.
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/// There will be no week 0 in 2007.
int day() const;
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/// Returns the day within the month (1 to 31).
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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);
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/// Computes the Julian day for a Gregorian calendar date and time.
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/// 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