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Date::ICal::Duration.3pm

NAME

Date::ICal::Duration - durations in iCalendar format, for math purposes.

VERSION

$Revision: 1.61 $

SYNOPSIS

     use Date::ICal::Duration;
 
     $d = Date::ICal::Duration->new( ical => '-P1W3DT2H3M45S' );
 
     $d = Date::ICal::Duration->new( weeks => 1, 
                                     days => 1,
                                     hours => 6,
                                     minutes => 15,
                                     seconds => 45); 
 
     # a one hour duration, without other components
     $d = Date::ICal::Duration->new( seconds => "3600"); 
 
     # Read-only accessors:
     $d->weeks;
     $d->days;
     $d->hours;
     $d->minutes;
     $d->seconds;
     $d->sign;
 
     # TODO: Resolve sign() discussion from rk-devel and update synopsis.
     
     $d->as_seconds ();   # returns just seconds
     $d->as_elements ();  # returns a hash of elements, like the accessors above
     $d->as_ical();       # returns an iCalendar duration string
 
 

DESCRIPTION

This is a trivial class for representing duration objects, for doing math in Date::ICal

AUTHOR

Rich Bowen, and the Reefknot team (www.reefknot.org)

Last touched by $Author: rbowen $

METHODS

Date::ICal::Duration has the following methods available:

new

A new Date::ICal::Duration object can be created with an iCalendar string :

     my $ical = Date::ICal::Duration->new ( ical => 'P3W2D' );
     # 3 weeks, 2 days, positive direction
     my $ical = Date::ICal::Duration->new ( ical => '-P6H3M30S' );
     # 6 hours, 3 minutes, 30 seconds, negative direction
 
 

Or with a number of seconds:

     my $ical = Date::ICal::Duration->new ( seconds => "3600" );
     # one hour positive
 
 

Or, better still, create it with components

     my $date = Date::ICal::Duration->new ( 
                            weeks => 6, 
                            days => 2, 
                            hours => 7,
                            minutes => 15,
                            seconds => 47,
                            sign => "+"
                            );
 
 

The sign defaults to ``+'', but ``+'' and ``-'' are legal values.

sign, weeks, days, hours, minutes, seconds

Read-only accessors for the elements of the object.

as_seconds

Returns the duration in raw seconds.

WARNING --- this folds in the number of days, assuming that they are always 86400 seconds long (which is not true twice a year in areas that honor daylight savings time). If you're using this for date arithmetic, consider using the add() method from a Date::ICal object, as this will behave better. Otherwise, you might experience some error when working with times that are specified in a time zone that observes daylight savings time.

as_days

     $days = $duration->as_days;
 
 

Returns the duration as a number of days. Not to be confused with the "days" method, this method returns the total number of days, rather than mod'ing out the complete weeks. Thus, if we have a duration of 33 days, "weeks" will return 4, "days" will return 5, but "as_days" will return 33.

Note that this is a lazy convenience function which is just weeks*7 + days.

as_ical

Return the duration in an iCalendar format value string (e.g., ``PT2H0M0S'')

as_elements

Returns the duration as a hashref of elements.

INTERNALS

head2 GENERAL MODEL

Internally, we store 3 data values: a number of days, a number of seconds (anything shorter than a day), and a sign (1 or -1). We are assuming that a day is 24 hours for purposes of this module; yes, we know that's not completely accurate because of daylight-savings-time switchovers, but it's mostly correct. Suggestions are welcome.

NOTE: The methods below SHOULD NOT be relied on to stay the same in future versions.

_set_from_ical ($self, $duration_string)

Converts a RFC2445 DURATION format string to the internal storage format.

_parse_ical_string ($string)

Regular expression for parsing iCalendar into usable values.

_set_from_components ($self, $hashref)

Converts from a hashref to the internal storage format. The hashref can contain elements ``sign'', ``weeks'', ``days'', ``hours'', ``minutes'', ``seconds''.

_set_from_ical ($self, $num_seconds)

Sets internal data storage properly if we were only given seconds as a parameter.

$self->_hms();

Return an arrayref to hours, minutes, and second components, or undef if nsecs is undefined. If given an arrayref, computes the new nsecs value for the duration.

$self->_wd()

Return an arrayref to weeks and day components, or undef if ndays is undefined. If Given an arrayref, computs the new ndays value for the duration.