Handles the time change part of the Posix timezone string like "M3.2.0/2:00:00". More...

#include <LocalTimeRK.h>

Public Member Functions
	LocalTimeChange ()
	Default contructor.

virtual	~LocalTimeChange ()
	Destructor.

	LocalTimeChange (const char *str)
	Constructs a time change object with a string format (calls parse()) More...

void	clear ()
	Clears all values.

void	parse (const char *str)
	Parses a time change string. More...

String	toString () const
	Turns the parsed data into a normalized string like "M3.2.0/2:00:00".

time_t	calculate (struct tm *pTimeInfo, LocalTimeHMS tzAdjust) const
	Calculate the time change in a given year. More...

Data Fields
int8_t	month = 0
	1-12, 1=January

int8_t	week = 0
	1-5, 1=first

int8_t	dayOfWeek = 0
	0-6, 0=Sunday, 1=Monday, ...

int8_t	valid = 0
	true = valid

LocalTimeHMS	hms
	Local time when timezone change occurs.

Detailed Description

Handles the time change part of the Posix timezone string like "M3.2.0/2:00:00".

Other formats with shortened time of day are also allowed like "M3.2.0/2" or even "M3.2.0" (midnight) are also allowed. Since the hour is local time, it can also be negative "M3.2.0/-1".

Constructor & Destructor Documentation

◆ LocalTimeChange()

LocalTimeChange::LocalTimeChange ( const char * str )

Constructs a time change object with a string format (calls parse())

Parameters

str	the time change string to parse

The time change string is part of the POSIX timezone specification and looks something like "M3.2.0/2:00:00".

Member Function Documentation

◆ calculate()

time_t LocalTimeChange::calculate	(	struct tm *	pTimeInfo,
		LocalTimeHMS	tzAdjust
	)		const

Calculate the time change in a given year.

On input, pTimeInfo must have a valid tm_year (121 = 2021) set.

On output, all struct tm values are set appropriately with UTC values of when the time change occurs.

◆ parse()

void LocalTimeChange::parse ( const char * str )

Parses a time change string.

Parameters

str	the time change string to parse

The time change string is part of the POSIX timezone specification and looks something like "M3.2.0/2:00:00".

M3 indicates that DST starts on the 3rd month (March)
2 is the week number (second week)
0 is the day of week (0 = Sunday)
2:00:00 at 2 AM local time, the transition occurs

Setting the week to 5 essentially means the last week of the month. If the month does not have a fifth week for that day of the week, then the fourth is used instead.

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

src/LocalTimeRK.h
src/LocalTimeRK.cpp