casacore::Time Class Reference

date and time enquiry functions, with some operations. More...

#include <Time.h>

Public Member Functions
	Time ()
	the default constructor returns an object with the present date and time
	Time (double jdn)
	Construct time with Julian day number.
	Time (uInt year, uInt month, uInt day, uInt hour=0, uInt min=0, double sec=0.0)
	Construct Time with Gregorian calendar.
	Time (const Time &time)
	Copy constructor.
double	julianDay () const
	return the Julian day (unit day)
double	modifiedJulianDay () const
	return the modified Julian day (unit day)
Time &	operator= (const Time &time)
	initialise the julian day data with Time class
double	operator- (const Time &begin)
Time	operator+ (const double plus)
Bool	operator== (const Time &other) const
Bool	operator!= (const Time &other) const
Bool	operator> (const Time &other) const
Bool	operator< (const Time &other) const
String	toString (const Bool iso=False) const
	if iso is True, then use ISO 8601 format otherwise, produce the string of the form Tue Mar 22 16:40:24 1994 with GMT time
const String	ISODate () const
	returns a String in ISO 8601 format YYYY-MM-DDTHH:MM:SS in GMT note: for dates beyond year 9999, use more digits for year
void	now ()
	reset date to the present instant
void	setDate (uInt year, uInt month, uInt day, uInt hour=0, uInt min=0, double sec=0.0)
double	age ()
	number of seconds which have elapsed since Time object was created or reset
uInt	seconds ()
	Return the seconds, minutes or hour part of the time.
double	dseconds ()
uInt	minutes ()
uInt	hours ()
uInt	dayOfMonth ()
uInt	month ()
uInt	year ()
uInt	dayOfWeek ()
uInt	dayOfYear ()
Static Public Member Functions
static uInt	howManyDaysInMonth ()
static uInt	howManyDaysInMonth (uInt month, uInt year)
static Bool	isLeapYear ()
static Bool	isLeapYear (uInt year)
static Int	timeZoneSeconds ()
	Returns the difference, in seconds, between UTC and local time.
static Double	timeZoneDays ()
	Same as timeZoneSeconds(), but returns fractional days rather than seconds.
static String	timeZoneName ()
	Returns a string, e.g.
Protected Attributes
uInt	mJulianDay
	Modified Julian day number 40587 modified Julian day number = 00:00:00 January 1, 1970, GMT.
double	mJulianDayfrac
	the fraction of the day
Friends
ostream &	operator<< (ostream &out, const Time &other)
	write the current time, GMT, in format Tue Mar 22 16:40:24 1994
istream &	operator>> (istream &, Time &)
	read in date, which must be in the following format month/day/year,hour:min:sec where month,day,year,hour,min and sec are uInt.

Detailed Description

date and time enquiry functions, with some operations.

Intended use:

Public interface

Review Status

Reviewed By:: Paul Shannon
Date Reviewed:: 1995/03/01
Test programs:: tTime

This class might be better named a Date object, especially given that more accurate Time classes are going to be required.

Prerequisite

you should understand the difference between "Julian" and "modified Julian" date

Synopsis

This class provides convenient date objects for the programmer. Once constructed, they may be compared, read and written, and queried for a wide variety of re-expressions. In a typical (?) use you might create a Time object, and then query it to find out the current month, day of the week, and whether it is a leap year. You can also find out the number of seconds which have elapsed since a specific Time.

Caution: This class should not be used for very high precision work; The time from epoch (1970;0) in seconds is interconverted between computer "double" values, and some loss of accuracy might result;

Example

 Time startTime;
 Time moonLanding (1969,7,14);
 cout << "date and time of moon landing: " << moonLanding << endl;
 cout << "day of week: " << moonLanding.dayOfWeek () << endl;
 cout << "day of year: " << moonLanding.dayOfYear () << endl;
 cout << "seconds since moon landing: " << moonLanding.age () << endl;
 cout << "weeks since moon landing: " <<
 moonLanding.age () / (60 * 60 * 24 * 7) << endl;
 cout << "seconds elapsed since start: " << startTime.age () << endl;

To Do

member function 'age' might be renamed 'elapsedTime'
A reference to the source of each algorithm should be provided.

Definition at line 88 of file Time.h.

Constructor & Destructor Documentation

casacore::Time::Time ( )

the default constructor returns an object with the present date and time

casacore::Time::Time ( double jdn )

Construct time with Julian day number.

casacore::Time::Time	(	uInt	year,
		uInt	month,
		uInt	day,
		uInt	hour = `0`,
		uInt	min = `0`,
		double	sec = `0.0`
	)

Construct Time with Gregorian calendar.

seconds after the minute [0,59.999] (include milliseconds)
minutes after the hour [0,59]
hours after midnight [0,23]
day of the month [1,31]
month of the year [1,12]
year. Beware, because '94' refers to the early Christian era, not the 20th century.

casacore::Time::Time ( const Time & time )

Copy constructor.

Member Function Documentation

double casacore::Time::age ( )

number of seconds which have elapsed since Time object was created or reset

uInt casacore::Time::dayOfMonth ( )

uInt casacore::Time::dayOfWeek ( )

uInt casacore::Time::dayOfYear ( )

double casacore::Time::dseconds ( )

uInt casacore::Time::hours ( )

static uInt casacore::Time::howManyDaysInMonth	(	uInt	month,
		uInt	year
	)			`[static]`

static uInt casacore::Time::howManyDaysInMonth ( ) [static]

static Bool casacore::Time::isLeapYear ( uInt year ) [static]

static Bool casacore::Time::isLeapYear ( ) [static]

const String casacore::Time::ISODate ( ) const [inline]

returns a String in ISO 8601 format YYYY-MM-DDTHH:MM:SS in GMT note: for dates beyond year 9999, use more digits for year

Definition at line 135 of file Time.h.

References toString(), and casacore::True.

double casacore::Time::julianDay ( ) const

return the Julian day (unit day)

uInt casacore::Time::minutes ( )

double casacore::Time::modifiedJulianDay ( ) const

return the modified Julian day (unit day)

uInt casacore::Time::month ( )

void casacore::Time::now ( )

reset date to the present instant

Bool casacore::Time::operator!= ( const Time & other ) const

Time casacore::Time::operator+ ( const double plus )

double casacore::Time::operator- ( const Time & begin )

Bool casacore::Time::operator< ( const Time & other ) const

Time& casacore::Time::operator= ( const Time & time )

initialise the julian day data with Time class

Bool casacore::Time::operator== ( const Time & other ) const

Bool casacore::Time::operator> ( const Time & other ) const

uInt casacore::Time::seconds ( )

Return the seconds, minutes or hour part of the time.

void casacore::Time::setDate	(	uInt	year,
		uInt	month,
		uInt	day,
		uInt	hour = `0`,
		uInt	min = `0`,
		double	sec = `0.0`
	)

static Double casacore::Time::timeZoneDays ( ) [static]

Same as timeZoneSeconds(), but returns fractional days rather than seconds.

static String casacore::Time::timeZoneName ( ) [static]

Returns a string, e.g.

"EST" or "MDT", describing the current local time zone.

static Int casacore::Time::timeZoneSeconds ( ) [static]

Returns the difference, in seconds, between UTC and local time.

Negative values are west of GMT, positive are east.

String casacore::Time::toString ( const Bool iso = False ) const

if iso is True, then use ISO 8601 format otherwise, produce the string of the form Tue Mar 22 16:40:24 1994 with GMT time

Referenced by ISODate().

uInt casacore::Time::year ( )

Friends And Related Function Documentation

ostream& operator<<	(	ostream &	out,
		const Time &	other
	)			`[friend]`

write the current time, GMT, in format Tue Mar 22 16:40:24 1994

Definition at line 140 of file Time.h.

istream& operator>>	(	istream &	,
		Time &
	)			`[friend]`

read in date, which must be in the following format month/day/year,hour:min:sec where month,day,year,hour,min and sec are uInt.

Member Data Documentation

uInt casacore::Time::mJulianDay [protected]

Modified Julian day number 40587 modified Julian day number = 00:00:00 January 1, 1970, GMT.

Definition at line 200 of file Time.h.

double casacore::Time::mJulianDayfrac [protected]

the fraction of the day

Definition at line 202 of file Time.h.

The documentation for this class was generated from the following file:

casacore/casa/OS/Time.h