Date::ICal::Duration(3)

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. Alas, Reefknot is no more. See http://datetime.perl.org/ for more modern modules.

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.