calendar_date Class Reference

Class calendar_date represents a gregorian-calendar date in the range [1752-09-14, 9999-12-31]. More...

#include <calendar_date.hpp>

Public Member Functions
	calendar_date ()
	calendar_date (jdn_t)
	calendar_date (ymd_t)
	calendar_date (int year, int month, int day)
calendar_date &	operator= (jdn_t)
calendar_date &	operator= (ymd_t)
calendar_date &	operator++ ()
calendar_date &	operator-- ()
calendar_date &	operator+= (int)
calendar_date &	operator-= (int)
int	julian_day_number (int)
int	julian_day_number () const
bool	operator== (calendar_date const &) const
bool	operator!= (calendar_date const &) const
bool	operator< (calendar_date const &) const
bool	operator<= (calendar_date const &) const
int	year () const
int	month () const
int	day () const
int	days_in_month () const
int	days_in_year () const
bool	is_leap_year () const
std::string	str () const

Static Public Member Functions
static bool	is_verified_jdn (int)

Static Public Attributes
static constexpr int	gregorian_epoch_jdn {2361222}
static constexpr int	last_yyyy_date_jdn {5373484}
static constexpr int	min_verified_jdn {1721120}
static constexpr int	max_verified_jdn {9999999}

Private Member Functions
void	assign_from_gregorian (int year, int month, int day)
void	cache_gregorian_elements () const

Private Attributes
int	jdn_
int	cached_year_
int	cached_month_
int	cached_day_

Detailed Description

Class calendar_date represents a gregorian-calendar date in the range [1752-09-14, 9999-12-31].

Date calculations are probably valid for later dates, and for earlier dates on the proleptic gregorian calendar, though only the given range is tested. The gregorian epoch is assumed to be 1752-09-14, the value predominant among the English-speaking peoples. The range limits are available as [gregorian_epoch(), last_yyyy_date()].

A date is internally represented as its 'julian day number', which is defined as number of days since January 1, 4713 BC according to the proleptic julian calendar. Seemingly-similar terms such as 'julian date' and 'julian day' are rendered irredeemably vague by diverse lay usage: they might be intended to mean the date on the julian as opposed to the gregorian calendar, or perhaps the number of days elapsed since the beginning of the current year. Which variant of julian day number the internal representation signifies need not be specified, and deliberately is not: astronomers may regard days as beginning at noon UTC, while most others probably think of days as beginning at midnight and respecting civil time in a local timezone, with appropriate daylight-saving adjustments. Such concerns are irrelevant to this class, which represents only a date, not a time of day.

The default ctor uses the current date.

By convention, the interface presents year, month, and day in origin one, so that concatenating their numeric representations as YYYYMMDD produces a valid ISO8601 date. Thus, the ranges of those elements are: year: [1752 | 1753, 9999] month: [1, 12] day: [1, 28 | 29 | 30 | 31] depending on context.

Functions that increment a date by a given number of months or years support two different conventions:

• A person born on a leap day attains legal majority on the first of March, not the twenty-eighth of February.
• Monthly business processes may be expected to occur in distinct calendar months. If the first occurrence falls on the thirty- first of January, then the third falls on the thirty-first of March, and therefore the second must fall on the twenty-eighth of February, not the first of March. This is defined as the 'curtate' case because the nonexistent thirty-first of February is shortened to the twenty-eighth.

Implicitly-declared special member functions do the right thing.

Constructor & Destructor Documentation

calendar_date() [1/4]

calendar_date::calendar_date

(

)

calendar_date() [2/4]

calendar_date::calendar_date ( jdn_t  z )

explicit

calendar_date() [3/4]

calendar_date::calendar_date ( ymd_t  z )

explicit

calendar_date() [4/4]

calendar_date::calendar_date	(	int	year,
		int	month,
		int	day
	)

Member Function Documentation

assign_from_gregorian()

void calendar_date::assign_from_gregorian ( int  year, int  month, int  day  )

private

cache_gregorian_elements()

void calendar_date::cache_gregorian_elements ( ) const

private

day()

int calendar_date::day

(

)

const

days_in_month()

int calendar_date::days_in_month

(

)

const

days_in_year()

int calendar_date::days_in_year

(

)

const

is_leap_year()

bool calendar_date::is_leap_year

(

)

const

is_verified_jdn()

bool calendar_date::is_verified_jdn ( int  z )

static

julian_day_number() [1/2]

int calendar_date::julian_day_number

(

)

const

julian_day_number() [2/2]

int calendar_date::julian_day_number

(

int

z

)

month()

int calendar_date::month

(

)

const

operator!=()

bool calendar_date::operator!=

(

calendar_date const &

z

)

const

operator++()

calendar_date & calendar_date::operator++

(

)

operator+=()

calendar_date & calendar_date::operator+=

(

int

i

)

operator--()

calendar_date & calendar_date::operator--

(

)

operator-=()

calendar_date & calendar_date::operator-=

(

int

i

)

operator<()

bool calendar_date::operator<

(

calendar_date const &

z

)

const

operator<=()

bool calendar_date::operator<=

(

calendar_date const &

z

)

const

operator=() [1/2]

calendar_date & calendar_date::operator=

(

jdn_t

j

)

operator=() [2/2]

calendar_date & calendar_date::operator=

(

ymd_t

ymd

)

operator==()

bool calendar_date::operator==

(

calendar_date const &

z

)

const

str()

std::string calendar_date::str

(

)

const

year()

int calendar_date::year

(

)

const

Member Data Documentation

cached_day_

int calendar_date::cached_day_

mutableprivate

cached_month_

int calendar_date::cached_month_

mutableprivate

cached_year_

int calendar_date::cached_year_

mutableprivate

gregorian_epoch_jdn

constexpr int calendar_date::gregorian_epoch_jdn {2361222}

staticconstexpr

jdn_

int calendar_date::jdn_

private

last_yyyy_date_jdn

constexpr int calendar_date::last_yyyy_date_jdn {5373484}

staticconstexpr

max_verified_jdn

constexpr int calendar_date::max_verified_jdn {9999999}

staticconstexpr

min_verified_jdn

constexpr int calendar_date::min_verified_jdn {1721120}

staticconstexpr

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

• calendar_date.hpp
• calendar_date.cpp