117 lines
3.2 KiB
Perl
117 lines
3.2 KiB
Perl
use warnings;
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use strict;
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package Data::ICal::Entry::TimeZone::Standard;
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use base qw/Data::ICal::Entry/;
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=head1 NAME
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Data::ICal::Entry::TimeZone::Standard - Represents a Standard Time base offset from UTC for parent TimeZone
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=head1 DESCRIPTION
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A time zone is unambiguously defined by the set of time measurement
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rules determined by the governing body for a given geographic
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area. These rules describe at a minimum the base offset from UTC for
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the time zone, often referred to as the Standard Time offset. Many
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locations adjust their Standard Time forward or backward by one hour,
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in order to accommodate seasonal changes in number of daylight hours,
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often referred to as Daylight Saving Time. Some locations adjust their
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time by a fraction of an hour. Standard Time is also known as Winter
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Time. Daylight Saving Time is also known as Advanced Time, Summer
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Time, or Legal Time in certain countries. The following table shows
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the changes in time zone rules in effect for New York City starting
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from 1967. Each line represents a description or rule for a particular
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observance.
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Effective Observance Rule
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Date (Date/Time) Offset Abbreviation
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1967-* last Sun in Oct, 02:00 -0500 EST
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1967-1973 last Sun in Apr, 02:00 -0400 EDT
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1974-1974 Jan 6, 02:00 -0400 EDT
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1975-1975 Feb 23, 02:00 -0400 EDT
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1976-1986 last Sun in Apr, 02:00 -0400 EDT
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1987-* first Sun in Apr, 02:00 -0400 EDT
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Note: The specification of a global time zone registry is not
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addressed by this document and is left for future study. However,
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implementers may find the Olson time zone database [TZ] a useful
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reference. It is an informal, public-domain collection of time zone
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information, which is currently being maintained by volunteer Internet
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participants, and is used in several operating systems. This database
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contains current and historical time zone information for a wide
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variety of locations around the globe; it provides a time zone
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identifier for every unique time zone rule set in actual use since
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1970, with historical data going back to the introduction of standard
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time.
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=head1 METHODS
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=cut
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=head2 ical_entry_type
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Returns C<STANDARD>, its iCalendar entry name.
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=cut
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sub ical_entry_type {'STANDARD'}
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=head2 mandatory_unique_properties
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According to the iCalendar standard, the following properties must be
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specified exactly one time in a standard time declaration:
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dtstart tzoffsetto tzoffsetfrom
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=cut
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sub mandatory_unique_properties {
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qw(
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dtstart
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tzoffsetto
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tzoffsetfrom
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);
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}
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=head2 optional_repeatable_properties
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According to the iCalendar standard, the following properties may be
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specified any number of times for a standard time declaration:
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comment rdate rrule tzname
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=cut
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sub optional_repeatable_properties {
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qw(
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comment
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rdate
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rrule
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tzname
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);
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}
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=head1 AUTHOR
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Best Practical Solutions, LLC E<lt>modules@bestpractical.comE<gt>
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=head1 LICENCE AND COPYRIGHT
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Copyright (c) 2005 - 2015, Best Practical Solutions, LLC. All rights reserved.
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This module is free software; you can redistribute it and/or
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modify it under the same terms as Perl itself. See L<perlartistic>.
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=cut
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1;
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