#include <evo/time.h>

Detailed Description

Structure holding a calendar date.

This holds year, month, and day fields
You can access the fields directly, or use methods as needed
Format with format(), parse with parse()
Validate with validate()
See also: TimeOfDay, DateTime

Example

#include <evo/time.h>
#include <evo/io.h>
using namespace evo;
int main() {
    Date date(1999, 12, 31);
    date.add_days(1);
    date.format(con().out) << NL;
    return 0;
}

Output:

2000-01-01

Public Member Functions
	Date ()
	Constructor. More...

	Date (int year, int month, int day)
	Constructor to initialize with date. More...

	Date (const Date &src)
	Copy constructor. More...

bool	add_days (int days)
	Add days to current date, subtract if negative. More...

bool	add_months (int months)
	Add months to current date, subtract if negative. More...

bool	add_years (int years)
	Add years to current date, subtract if negative. More...

int	compare (const Date &oth) const
	Compare to another date. More...

template<class T >
T &	format (T &out, char delim='-') const
	Format date to String or Stream. More...

template<class T >
T &	format_yearday (T &out, char delim='-')
	Format ordinal date to String or Stream. More...

ulong	get_jdn () const
	Get Julian Day Number for current date. More...

bool	operator!= (const Date &oth) const
	Compare for inequality with another date. More...

bool	operator< (const Date &oth) const
	Compare whether less than another date. More...

bool	operator<= (const Date &oth) const
	Compare whether less than or equal to another date. More...

Date &	operator= (const Date &src)
	Assignment operator. More...

bool	operator== (const Date &oth) const
	Compare for equality with another date. More...

bool	operator> (const Date &oth) const
	Compare whether greater than another date. More...

bool	operator>= (const Date &oth) const
	Compare whether greater than or equal to another date. More...

bool	parse (const SubString &str)
	Set date from parsing standard date string (used internally). More...

bool	parse_std_impl (const char &inp, const char end)
	Set date from parsing standard date string (used internally). More...

void	set ()
	Set all fields to 0, which is not a valid date. More...

bool	set (int new_year, int new_month, int new_day)
	Set new date fields. More...

bool	set_jdn (ulong jdn)
	Set date converted from Julian Day Number. More...

void	set_local ()
	Set to current date in local time zone. More...

void	set_utc ()
	Set to current date in UTC. More...

bool	validate () const
	Validate current date. More...

Static Public Member Functions
static ulong	calc_jdn (int year, int month, int day)
	Calculate Julian Day Number from date fields. More...

static int	days_per_month (int month, bool leap_year)
	Helper to get number of days per given month. More...

static int	days_per_month (int month, int year)
	Helper to get number of days per given month in given year. More...

static bool	is_leap_year (int year)
	Helper to check whether given year is a leap year. More...

static SubString	month_name (int month)
	Get name of given month. More...

static SubString	month_name3 (int month)
	Get abbreviated name of given month. More...

Public Attributes
int	day
	Day of month (1 - 31) More...

int	month
	Month of year (1 - 12) More...

int	year
	4 digit year (1000 - 9999) More...

Static Public Attributes
static const int	DAY_MAX = 31
	Max day for any month – see days_per_month() More...

static const int	DAY_MIN = 1
	First day per month. More...

static const ulong	JDN_MIN = 2086302
	Minimum Julian Day Number for Jan 1, 1000. More...

static const ulong	JDN_MOD = 2400000
	Julian Day Number for Modified Julian Day, subtract from JDN to get MJD (smaller number), add back for normal JDN. More...

static const int	MONTH_MAX = 12
	Last month per year. More...

static const int	MONTH_MIN = 1
	First month per year. More...

static const int	YEAR_MAX = 9999
	Maximum year for 4 digits. More...

static const int	YEAR_MIN = 1000
	Minimum year for 4 digits. More...

Constructor & Destructor Documentation

◆ Date() [1/3]

Date ( )

inline

Constructor.

◆ Date() [2/3]

Date	(	int	year,
		int	month,
		int	day
	)

inline

Constructor to initialize with date.

This does not validate the fields, use valid_date() to check this

Parameters

year	4 digit year
month	Month of year
day	Day of month

◆ Date() [3/3]

Date ( const Date & src )

inline

Copy constructor.

Parameters

src	Source to copy

Member Function Documentation

◆ add_days()

bool add_days ( int days )

inline

Add days to current date, subtract if negative.

This adds the given days and adjusts months and years accordingly

Parameters

days	Number of days to add, negative to subtract

Returns: Whether successful, false if current date is invalid before or after modification

◆ add_months()

bool add_months ( int months )

inline

Add months to current date, subtract if negative.

This adds the given months and adjusts day of month to last day of month if not valid for the new year and month

Parameters

months Number of months to add, negative to subtract

Returns: Whether successful, false if current date is invalid before or after modification

◆ add_years()

bool add_years ( int years )

inline

Add years to current date, subtract if negative.

This adds the given years and adjusts day of month to last day of month if not valid for the new year and month

Parameters

years Number of years to add, negative to subtract

Returns: Whether successful, false if current date is invalid before or after modification

◆ calc_jdn()

static ulong calc_jdn	(	int	year,
		int	month,
		int	day
	)

inlinestatic

Calculate Julian Day Number from date fields.

This does not validate the input
Notes:
- Julian Days normally begin at noon, but this uses it purely as a date and pretends they begin at midnight – time of day can be tracked separately
- Not related to the Julian calendar

Parameters

year	Year to use (1000 - 9999)
month	Month of year to use (1 - 12)
day	Day of month to use (1 - 31)

Returns: Julian Day Number for date

◆ compare()

int compare ( const Date & oth ) const

inline

Compare to another date.

Parameters

oth	Other date to compare to

Returns: Result (<0 if this is less, 0 if equal, >0 if this is greater)

◆ days_per_month() [1/2]

static int days_per_month	(	int	month,
		bool	leap_year
	)

inlinestatic

Helper to get number of days per given month.

Parameters

month	Month to get number of days of (1 - 12)
leap_year	Whether this is for a leap year, which affects the result for `month=2`

Returns: Number of days in month

◆ days_per_month() [2/2]

static int days_per_month	(	int	month,
		int	year
	)

inlinestatic

Helper to get number of days per given month in given year.

Parameters

month	Month to get number of days of (1 - 12)
year	Year for month, used to determine whether a leap year applies for `month=2`

Returns: Number of days in month

◆ format()

T& format	(	T &	out,
		char	delim = `'-'`
	)		const

inline

Format date to String or Stream.

Date syntax is based on ISO 8601:
- YYYY-MM-DD – with default delimiter, other delimiters may be use but aren't considered standard
- YYYYMMDD – with no delimiter
See also: format_yearday()

Template Parameters

T	String/Stream type, inferred from argument

Parameters

out	Output String/Stream to format to
delim	Delimiter to use between fields, 0 for none

Returns: Reference to out

◆ format_yearday()

T& format_yearday	(	T &	out,
		char	delim = `'-'`
	)

inline

Format ordinal date to String or Stream.

Date syntax is based on ISO 8601 ordinal date:
- YYYY-DDD – ordinal date with default delimiter, other delimiters may be use but aren't considered standard
- YYYYDDD – ordinal date with no delimiter
See also: format()

Template Parameters

Output String/Stream type, inferred from argument

Parameters

out	Output String/Stream to format to
delim	Delimiter to use between fields, 0 for none

Returns: Reference to out

◆ get_jdn()

ulong get_jdn ( ) const

inline

Get Julian Day Number for current date.

This is useful for turning a date into a single number in day units that is easy to add/subtract and convert back to a date
Call set_jdn() to convert a JDN back into date fields
For a Modified JDN: subtract JDN_MOD from a valid (non-zero) result, then add it back again
Notes:
- Julian Days normally begin at noon, but this uses it purely as a date and pretends they begin at midnight – time of day can be tracked separately
- Not related to the Julian calendar

Returns: Julian Day Number for current date, 0 if current date is not valid

◆ is_leap_year()

static bool is_leap_year ( int year )

inlinestatic

Helper to check whether given year is a leap year.

Leap years are years divisible by 400, or years divisible by 4 but not divisible by 100

Parameters

year	Year to check

Returns: Whether a leap year

◆ month_name()

static SubString month_name ( int month )

inlinestatic

Get name of given month.

String is always static/immutable and terminated

Parameters

month Month to get name of (1 - 12)

Returns: Name of month, null if invalid month

◆ month_name3()

static SubString month_name3 ( int month )

inlinestatic

Get abbreviated name of given month.

String is always static/immutable and terminated

Parameters

month Month to get name of (1 - 12)

Returns: Name of month, null if invalid month

◆ operator!=()

bool operator!= ( const Date & oth ) const

inline

Compare for inequality with another date.

Parameters

oth	Other date to compare to

Returns: Whether inequal

◆ operator<()

bool operator< ( const Date & oth ) const

inline

Compare whether less than another date.

Parameters

oth	Other date to compare to

Returns: Whether less than

◆ operator<=()

bool operator<= ( const Date & oth ) const

inline

Compare whether less than or equal to another date.

Parameters

oth	Other date to compare to

Returns: Whether less than or equal

◆ operator=()

Date& operator= ( const Date & src )

inline

Assignment operator.

Parameters

src	Source to copy

Returns: This

◆ operator==()

bool operator== ( const Date & oth ) const

inline

Compare for equality with another date.

Parameters

oth	Other date to compare to

Returns: Whether equal

◆ operator>()

bool operator> ( const Date & oth ) const

inline

Compare whether greater than another date.

Parameters

oth	Other date to compare to

Returns: Whether greater than

◆ operator>=()

bool operator>= ( const Date & oth ) const

inline

Compare whether greater than or equal to another date.

Parameters

oth	Other date to compare to

Returns: Whether greater than or equal

◆ parse()

bool parse ( const SubString & str )

inline

Set date from parsing standard date string (used internally).

Supported date syntax is based on ISO 8601:
- YYYY-MM-DD – full date with delimiter
- YYYYMMDD – shorter version without delimiters
- YYYY-DDD – ordinal date with delimiter, with 4 digit year (1000 - 999) and day of year (1 - 366)
- YYYYDDD – ordinal date, shorter version without delimiters
- Alternate delimiters supported: SPACE, SLASH (/), PERIOD (.)

Parameters

str	String to parse

Returns: Whether successful, false on bad input or unrecognized format

◆ parse_std_impl()

bool parse_std_impl	(	const char *&	inp,
		const char *	end
	)

inline

Set date from parsing standard date string (used internally).

Supported date syntax is based on ISO 8601:
- YYYY-MM-DD – full date with delimiter
- YYYYMMDD – shorter version without delimiters
- YYYY-DDD – ordinal date with delimiter, with 4 digit year (1000 - 999) and day of year (1 - 366)
- YYYYDDD – ordinal date, shorter version without delimiters
- Alternate delimiters supported: SPACE, SLASH (/), PERIOD (.)

Parameters

inp	Start parsing pointer (must be `<= end`), set to stop position [in/out]
end	End of string pointer, must not be NULL

Returns: Whether successful, false on bad input or unrecognized format

◆ set() [1/2]

void set ( )

inline

Set all fields to 0, which is not a valid date.

◆ set() [2/2]

bool set	(	int	new_year,
		int	new_month,
		int	new_day
	)

inline

Set new date fields.

This does validate the fields before setting them

Parameters

new_year	New year value
new_month	New month value
new_day	New day value

Returns: Whether successful, false if one of the fields is invalid

◆ set_jdn()

bool set_jdn ( ulong jdn )

inline

Set date converted from Julian Day Number.

Call get_jdn() to convert date into a JDN first – this is useful for turning a date into a single number in day units that is easy to add/subtract
For a Modified JDN: subtract JDN_MOD from a valid (non-zero) result, then add it back again before calling this
Notes:
- Julian Days normally begin at noon, but this uses it purely as a date and pretends they begin at midnight – time of day can be tracked separately
- Not related to the Julian calendar

Parameters

jdn	Julian Day Number to set

Returns: Whether successful, false if JDN is invalid (0 or less than JDN_MIN)

◆ set_local()

void set_local ( )

inline

Set to current date in local time zone.

◆ set_utc()

void set_utc ( )

inline

Set to current date in UTC.

◆ validate()

bool validate ( ) const

inline

Validate current date.

Returns: Whether date is valid, false if any field is invalid (out of range)

Member Data Documentation

◆ day

int day

Day of month (1 - 31)

◆ DAY_MAX

const int DAY_MAX = 31

static

Max day for any month – see days_per_month()

◆ DAY_MIN

const int DAY_MIN = 1

static

First day per month.

◆ JDN_MIN

const ulong JDN_MIN = 2086302

static

Minimum Julian Day Number for Jan 1, 1000.

◆ JDN_MOD

const ulong JDN_MOD = 2400000

static

Julian Day Number for Modified Julian Day, subtract from JDN to get MJD (smaller number), add back for normal JDN.

◆ month

int month

Month of year (1 - 12)

◆ MONTH_MAX

const int MONTH_MAX = 12

static

Last month per year.

◆ MONTH_MIN

const int MONTH_MIN = 1

static

First month per year.

◆ year

int year

4 digit year (1000 - 9999)

◆ YEAR_MAX

const int YEAR_MAX = 9999

static

Maximum year for 4 digits.

◆ YEAR_MIN

const int YEAR_MIN = 1000

static

Minimum year for 4 digits.

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

evo/time.h

Detailed Description

Public Member Functions

Static Public Member Functions

Public Attributes

Static Public Attributes

Constructor & Destructor Documentation

◆ Date() [1/3]

◆ Date() [2/3]

◆ Date() [3/3]

Member Function Documentation

◆ add_days()

◆ add_months()

◆ add_years()

◆ calc_jdn()

◆ compare()

◆ days_per_month() [1/2]

◆ days_per_month() [2/2]

◆ format()

◆ format_yearday()

◆ get_jdn()

◆ is_leap_year()

◆ month_name()

◆ month_name3()

◆ operator!=()

◆ operator<()

◆ operator<=()

◆ operator=()

◆ operator==()

◆ operator>()

◆ operator>=()

◆ parse()

◆ parse_std_impl()

◆ set() [1/2]

◆ set() [2/2]

◆ set_jdn()

◆ set_local()

◆ set_utc()

◆ validate()

Member Data Documentation

◆ day

◆ DAY_MAX

◆ DAY_MIN

◆ JDN_MIN

◆ JDN_MOD

◆ month

◆ MONTH_MAX

◆ MONTH_MIN

◆ year

◆ YEAR_MAX

◆ YEAR_MIN