package DateTime::TimeZone; use 5.008004; use strict; use warnings; use namespace::autoclean; our $VERSION = '2.62'; # Note that while we make use of DateTime::Duration in this module if we # actually try to load it here all hell breaks loose with circular # dependencies. use DateTime::TimeZone::Catalog; use DateTime::TimeZone::Floating; use DateTime::TimeZone::Local; use DateTime::TimeZone::OffsetOnly; use DateTime::TimeZone::OlsonDB::Change; use DateTime::TimeZone::UTC; use Module::Runtime qw( require_module ); use Params::ValidationCompiler 0.13 qw( validation_for ); use Specio::Library::Builtins; use Specio::Library::String; use Try::Tiny; ## no critic (ValuesAndExpressions::ProhibitConstantPragma) use constant INFINITY => 100**1000; use constant NEG_INFINITY => -1 * ( 100**1000 ); # the offsets for each span element use constant UTC_START => 0; use constant UTC_END => 1; use constant LOCAL_START => 2; use constant LOCAL_END => 3; use constant OFFSET => 4; use constant IS_DST => 5; use constant SHORT_NAME => 6; my %SpecialName = map { $_ => 1 } qw( EST MST HST CET EET MET WET EST5EDT CST6CDT MST7MDT PST8PDT ); { my $validator = validation_for( name => '_check_new_params', name_is_optional => 1, params => { name => { type => t('NonEmptyStr'), }, }, ); sub new { shift; my %p = $validator->(@_); if ( exists $DateTime::TimeZone::Catalog::LINKS{ $p{name} } ) { $p{name} = $DateTime::TimeZone::Catalog::LINKS{ $p{name} }; } elsif ( exists $DateTime::TimeZone::Catalog::LINKS{ uc $p{name} } ) { $p{name} = $DateTime::TimeZone::Catalog::LINKS{ uc $p{name} }; } unless ( $p{name} =~ m{/} || $SpecialName{ $p{name} } ) { if ( $p{name} eq 'floating' ) { return DateTime::TimeZone::Floating->instance; } if ( $p{name} eq 'local' ) { return DateTime::TimeZone::Local->TimeZone(); } if ( $p{name} eq 'UTC' || $p{name} eq 'Z' ) { return DateTime::TimeZone::UTC->instance; } return DateTime::TimeZone::OffsetOnly->new( offset => $p{name} ); } if ( $p{name} =~ m{Etc/(?:GMT|UTC)(\+|-)(\d{1,2})}i ) { # Etc/GMT+4 is actually UTC-4. For more info, see # https://data.iana.org/time-zones/tzdb/etcetera my $sign = $1 eq '-' ? '+' : '-'; my $hours = $2; die "The timezone '$p{name}' is an invalid name.\n" unless $hours <= 14; return DateTime::TimeZone::OffsetOnly->new( offset => "${sign}${hours}:00" ); } my $subclass = $p{name}; $subclass =~ s{/}{::}g; $subclass =~ s/-(\d)/_Minus$1/; $subclass =~ s/\+/_Plus/; $subclass =~ s/-/_/g; my $real_class = "DateTime::TimeZone::$subclass"; die "The timezone '$p{name}' is an invalid name.\n" unless $real_class =~ /^\w+(::\w+)*$/; unless ( $real_class->can('instance') ) { ($real_class) = $real_class =~ m{\A([a-zA-Z0-9_]+(?:::[a-zA-Z0-9_]+)*)\z}; my $e; try { ## no critic (Variables::RequireInitializationForLocalVars) local $SIG{__DIE__}; require_module($real_class); } catch { $e = $_; }; if ($e) { my $regex = join '.', split /::/, $real_class; $regex .= '\\.pm'; if ( $e =~ /^Can't locate $regex/i ) { die "The timezone '$p{name}' could not be loaded, or is an invalid name.\n"; } else { die $e; } } } my $zone = $real_class->instance( name => $p{name}, is_olson => 1 ); if ( $zone->is_olson() ) { my $object_version = $zone->can('olson_version') ? $zone->olson_version() : 'unknown'; my $catalog_version = DateTime::TimeZone::Catalog->OlsonVersion(); if ( $object_version ne $catalog_version ) { warn "Loaded $real_class, which is from a different version ($object_version) of the Olson database than this installation of DateTime::TimeZone ($catalog_version).\n"; } } return $zone; } } { my $validator = validation_for( name => '_check_init_params', name_is_optional => 1, params => { name => { type => t('NonEmptyStr'), }, spans => { type => t('ArrayRef'), }, is_olson => { type => t('Bool'), default => 0, }, }, ); ## no critic (Subroutines::ProhibitUnusedPrivateSubroutines) sub _init { my $class = shift; my %p = $validator->(@_); my $self = bless { name => $p{name}, spans => $p{spans}, is_olson => $p{is_olson}, }, $class; foreach my $k (qw( last_offset last_observance rules max_year )) { my $m = "_$k"; $self->{$k} = $self->$m() if $self->can($m); } return $self; } ## use critic } sub is_olson { $_[0]->{is_olson} } sub is_dst_for_datetime { my $self = shift; my $span = $self->_span_for_datetime( 'utc', $_[0] ); return $span->[IS_DST]; } sub offset_for_datetime { my $self = shift; my $span = $self->_span_for_datetime( 'utc', $_[0] ); return $span->[OFFSET]; } sub offset_for_local_datetime { my $self = shift; my $span = $self->_span_for_datetime( 'local', $_[0] ); return $span->[OFFSET]; } sub short_name_for_datetime { my $self = shift; my $span = $self->_span_for_datetime( 'utc', $_[0] ); return $span->[SHORT_NAME]; } sub _span_for_datetime { my $self = shift; my $type = shift; my $dt = shift; my $method = $type . '_rd_as_seconds'; my $end = $type eq 'utc' ? UTC_END : LOCAL_END; my $span; my $seconds = $dt->$method(); if ( $seconds < $self->max_span->[$end] ) { $span = $self->_spans_binary_search( $type, $seconds ); } else { my $until_year = $dt->utc_year + 1; $span = $self->_generate_spans_until_match( $until_year, $seconds, $type ); } # This means someone gave a local time that doesn't exist # (like during a transition into savings time) unless ( defined $span ) { my $err = 'Invalid local time for date'; $err .= q{ } . $dt->iso8601 if $type eq 'utc'; $err .= ' in time zone: ' . $self->name; $err .= "\n"; die $err; } return $span; } sub _spans_binary_search { my $self = shift; my ( $type, $seconds ) = @_; my ( $start, $end ) = _keys_for_type($type); my $min = 0; my $max = scalar @{ $self->{spans} } + 1; my $i = int( $max / 2 ); # special case for when there are only 2 spans $i++ if $max % 2 && $max != 3; $i = 0 if @{ $self->{spans} } == 1; while (1) { my $current = $self->{spans}[$i]; if ( $seconds < $current->[$start] ) { $max = $i; my $c = int( ( $i - $min ) / 2 ); $c ||= 1; $i -= $c; return if $i < $min; } elsif ( $seconds >= $current->[$end] ) { $min = $i; my $c = int( ( $max - $i ) / 2 ); $c ||= 1; $i += $c; return if $i >= $max; } else { # Special case for overlapping ranges because of DST and # other weirdness (like Alaska's change when bought from # Russia by the US). Always prefer latest span. if ( $current->[IS_DST] && $type eq 'local' ) { # Asia/Dhaka in 2009j goes into DST without any known # end-of-DST date (wtf, Bangladesh). return $current if $current->[UTC_END] == INFINITY; my $next = $self->{spans}[ $i + 1 ]; # Sometimes we will get here and the span we're # looking at is the last that's been generated so far. # We need to try to generate one more or else we run # out. $next ||= $self->_generate_next_span; die "No next span in $self->{max_year}" unless defined $next; if ( ( !$next->[IS_DST] ) && $next->[$start] <= $seconds && $seconds <= $next->[$end] ) { return $next; } } return $current; } } } sub _generate_next_span { my $self = shift; my $last_idx = $#{ $self->{spans} }; my $max_span = $self->max_span; # Kind of a hack, but AFAIK there are no zones where it takes # _more_ than a year for a _future_ time zone change to occur, so # by looking two years out we can ensure that we will find at # least one more span. Of course, I will no doubt be proved wrong # and this will cause errors. $self->_generate_spans_until_match( $self->{max_year} + 2, $max_span->[UTC_END] + ( 366 * 86400 ), 'utc' ); return $self->{spans}[ $last_idx + 1 ]; } sub _generate_spans_until_match { my $self = shift; my $generate_until_year = shift; my $seconds = shift; my $type = shift; my @changes; my @rules = @{ $self->_rules }; foreach my $year ( $self->{max_year} .. $generate_until_year ) { ## no critic (ControlStructures::ProhibitCStyleForLoops) for ( my $x = 0; $x < @rules; $x++ ) { my $last_offset_from_std; if ( @rules == 2 ) { $last_offset_from_std = $x ? $rules[0]->offset_from_std : $rules[1]->offset_from_std; } elsif ( @rules == 1 ) { $last_offset_from_std = $rules[0]->offset_from_std; } else { my $count = scalar @rules; die "Cannot generate future changes for zone with $count infinite rules\n"; } my $rule = $rules[$x]; my $next = $rule->utc_start_datetime_for_year( $year, $self->{last_offset}, $last_offset_from_std ); # don't bother with changes we've seen already next if $next->utc_rd_as_seconds < $self->max_span->[UTC_END]; push @changes, DateTime::TimeZone::OlsonDB::Change->new( type => 'rule', utc_start_datetime => $next, local_start_datetime => $next + DateTime::Duration->new( seconds => $self->{last_observance}->total_offset + $rule->offset_from_std ), short_name => $self->{last_observance} ->formatted_short_name( $rule->letter ), observance => $self->{last_observance}, rule => $rule, ); } } $self->{max_year} = $generate_until_year; my @sorted = sort { $a->utc_start_datetime <=> $b->utc_start_datetime } @changes; my ( $start, $end ) = _keys_for_type($type); my $match; ## no critic (ControlStructures::ProhibitCStyleForLoops) for ( my $x = 1; $x < @sorted; $x++ ) { my $span = DateTime::TimeZone::OlsonDB::Change::two_changes_as_span( @sorted[ $x - 1, $x ] ); $span = _span_as_array($span); push @{ $self->{spans} }, $span; $match = $span if $seconds >= $span->[$start] && $seconds < $span->[$end]; } return $match; } sub max_span { $_[0]->{spans}[-1] } sub _keys_for_type { $_[0] eq 'utc' ? ( UTC_START, UTC_END ) : ( LOCAL_START, LOCAL_END ); } sub _span_as_array { [ @{ $_[0] }{ qw( utc_start utc_end local_start local_end offset is_dst short_name ) } ]; } sub is_floating {0} sub is_utc {0} sub has_dst_changes {0} sub name { $_[0]->{name} } sub category { ( split /\//, $_[0]->{name}, 2 )[0] } sub is_valid_name { my $class = shift; my $name = shift; my $tz = try { ## no critic (Variables::RequireInitializationForLocalVars) local $SIG{__DIE__}; $class->new( name => $name ); }; return $tz && $tz->isa('DateTime::TimeZone') ? 1 : 0; } sub STORABLE_freeze { my $self = shift; return $self->name; } sub STORABLE_thaw { my $self = shift; shift; my $serialized = shift; my $class = ref $self || $self; my $obj; if ( $class->isa(__PACKAGE__) ) { $obj = __PACKAGE__->new( name => $serialized ); } else { $obj = $class->new( name => $serialized ); } %$self = %$obj; return $self; } # # Functions # sub offset_as_seconds { my $offset = shift; $offset = shift if try { ## no critic (Variables::RequireInitializationForLocalVars) local $SIG{__DIE__}; $offset->isa('DateTime::TimeZone'); }; return undef unless defined $offset; return 0 if $offset eq '0'; my ( $sign, $hours, $minutes, $seconds ); if ( $offset =~ /^([\+\-])?(\d\d?):(\d\d)(?::(\d\d))?$/ ) { ( $sign, $hours, $minutes, $seconds ) = ( $1, $2, $3, $4 ); } elsif ( $offset =~ /^([\+\-])?(\d\d)(\d\d)(\d\d)?$/ ) { ( $sign, $hours, $minutes, $seconds ) = ( $1, $2, $3, $4 ); } else { return undef; } $sign = '+' unless defined $sign; return undef unless $hours >= 0 && $hours <= 99; return undef unless $minutes >= 0 && $minutes <= 59; return undef unless !defined($seconds) || ( $seconds >= 0 && $seconds <= 59 ); my $total = $hours * 3600 + $minutes * 60; $total += $seconds if $seconds; $total *= -1 if $sign eq '-'; return $total; } sub offset_as_string { my $offset = shift; $offset = shift if try { ## no critic (Variables::RequireInitializationForLocalVars) local $SIG{__DIE__}; $offset->isa('DateTime::TimeZone'); }; my $sep = shift || q{}; return undef unless defined $offset; return undef unless $offset >= -359999 && $offset <= 359999; my $sign = $offset < 0 ? '-' : '+'; $offset = abs($offset); my $hours = int( $offset / 3600 ); $offset %= 3600; my $mins = int( $offset / 60 ); $offset %= 60; my $secs = int($offset); return ( $secs ? sprintf( '%s%02d%s%02d%s%02d', $sign, $hours, $sep, $mins, $sep, $secs ) : sprintf( '%s%02d%s%02d', $sign, $hours, $sep, $mins ) ); } # These methods all operate on data contained in the DateTime/TimeZone/Catalog.pm file. sub all_names { return wantarray ? @DateTime::TimeZone::Catalog::ALL : [@DateTime::TimeZone::Catalog::ALL]; } sub categories { return wantarray ? @DateTime::TimeZone::Catalog::CATEGORY_NAMES : [@DateTime::TimeZone::Catalog::CATEGORY_NAMES]; } sub links { return wantarray ? %DateTime::TimeZone::Catalog::LINKS : {%DateTime::TimeZone::Catalog::LINKS}; } sub names_in_category { shift if $_[0]->isa('DateTime::TimeZone'); return unless exists $DateTime::TimeZone::Catalog::CATEGORIES{ $_[0] }; return wantarray ? @{ $DateTime::TimeZone::Catalog::CATEGORIES{ $_[0] } } : $DateTime::TimeZone::Catalog::CATEGORIES{ $_[0] }; } sub countries { wantarray ? ( sort keys %DateTime::TimeZone::Catalog::ZONES_BY_COUNTRY ) : [ sort keys %DateTime::TimeZone::Catalog::ZONES_BY_COUNTRY ]; } sub names_in_country { shift if $_[0]->isa('DateTime::TimeZone'); return unless exists $DateTime::TimeZone::Catalog::ZONES_BY_COUNTRY{ lc $_[0] }; return wantarray ? @{ $DateTime::TimeZone::Catalog::ZONES_BY_COUNTRY{ lc $_[0] } } : $DateTime::TimeZone::Catalog::ZONES_BY_COUNTRY{ lc $_[0] }; } 1; # ABSTRACT: Time zone object base class and factory __END__ =pod =encoding UTF-8 =head1 NAME DateTime::TimeZone - Time zone object base class and factory =head1 VERSION version 2.62 =head1 SYNOPSIS use DateTime; use DateTime::TimeZone; my $tz = DateTime::TimeZone->new( name => 'America/Chicago' ); my $dt = DateTime->now(); my $offset = $tz->offset_for_datetime($dt); =head1 DESCRIPTION This class is the base class for all time zone objects. A time zone is represented internally as a set of observances, each of which describes the offset from GMT for a given time period. Note that without the L module, this module does not do much. It's primary interface is through a L object, and most users will not need to directly use C methods. =head2 Special Case Platforms If you are on the Win32 platform, you will want to also install L. This will enable you to specify a time zone of C<'local'> when creating a L object. If you are on HPUX, install L. This provides support for HPUX style time zones like C<'MET-1METDST'>. =head1 USAGE This class has the following methods: =head2 DateTime::TimeZone->new( name => $tz_name ) Given a valid time zone name, this method returns a new time zone blessed into the appropriate subclass. Subclasses are named for the given time zone, so that the time zone "America/Chicago" is the DateTime::TimeZone::America::Chicago class. If the name given is a "link" name in the Olson database, the object created may have a different name. For example, there is a link from the old "EST5EDT" name to "America/New_York". When loading a time zone from the Olson database, the constructor checks the version of the loaded class to make sure it matches the version of the current DateTime::TimeZone installation. If they do not match it will issue a warning. This is useful because time zone names may fall out of use, but you may have an old module file installed for that time zone. There are also several special values that can be given as names. If the "name" parameter is "floating", then a C object is returned. A floating time zone does not have I offset, and is always the same time. This is useful for calendaring applications, which may need to specify that a given event happens at the same I time, regardless of where it occurs. See L for more details. If the "name" parameter is "UTC", then a C object is returned. If the "name" is an offset string, it is converted to a number, and a C object is returned. =head3 The "local" time zone If the "name" parameter is "local", then the module attempts to determine the local time zone for the system. The method for finding the local zone varies by operating system. See the appropriate module for details of how we check for the local time zone. =over 4 =item * L =item * L =item * L =item * L =item * L =back If a local time zone is not found, then an exception will be thrown. This exception will always stringify to something containing the text C<"Cannot determine local time zone">. If you are writing code for users to run on systems you do not control, you should try to account for the possibility that this exception may be thrown. Falling back to UTC might be a reasonable alternative. When writing tests for your modules that might be run on others' systems, you are strongly encouraged to either not use C when creating L objects or to set C<$ENV{TZ}> to a known value in your test code. All of the per-OS classes check this environment variable. =head2 $tz->offset_for_datetime( $dt ) Given a C object, this method returns the offset in seconds for the given datetime. This takes into account historical time zone information, as well as Daylight Saving Time. The offset is determined by looking at the object's UTC Rata Die days and seconds. =head2 $tz->offset_for_local_datetime( $dt ) Given a C object, this method returns the offset in seconds for the given datetime. Unlike the previous method, this method uses the local time's Rata Die days and seconds. This should only be done when the corresponding UTC time is not yet known, because local times can be ambiguous due to Daylight Saving Time rules. =head2 $tz->is_dst_for_datetime( $dt ) Given a C object, this method returns true if the DateTime is currently in Daylight Saving Time. =head2 $tz->name Returns the name of the time zone. =head2 $tz->short_name_for_datetime( $dt ) Given a C object, this method returns the "short name" for the current observance and rule this datetime is in. These are names like "EST", "GMT", etc. It is B recommended that you do not rely on these names for anything other than display. These names are not official, and many of them are simply the invention of the Olson database maintainers. Moreover, these names are not unique. For example, there is an "EST" at both -0500 and +1000/+1100. =head2 $tz->is_floating Returns a boolean indicating whether or not this object represents a floating time zone, as defined by L. =head2 $tz->is_utc Indicates whether or not this object represents the UTC (GMT) time zone. =head2 $tz->has_dst_changes Indicates whether or not this zone has I had a change to and from DST, either in the past or future. =head2 $tz->is_olson Returns true if the time zone is a named time zone from the Olson database. =head2 $tz->category Returns the part of the time zone name before the first slash. For example, the "America/Chicago" time zone would return "America". =head2 DateTime::TimeZone->is_valid_name($name) Given a string, this method returns a boolean value indicating whether or not the string is a valid time zone name. If you are using C, any aliases you've created will be valid. =head2 DateTime::TimeZone->all_names This returns a pre-sorted list of all the time zone names. This list does not include link names. In scalar context, it returns an array reference, while in list context it returns an array. =head2 DateTime::TimeZone->categories This returns a list of all time zone categories. In scalar context, it returns an array reference, while in list context it returns an array. =head2 DateTime::TimeZone->links This returns a hash of all time zone links, where the keys are the old, deprecated names, and the values are the new names. In scalar context, it returns a hash reference, while in list context it returns a hash. =head2 DateTime::TimeZone->names_in_category( $category ) Given a valid category, this method returns a list of the names in that category, without the category portion. So the list for the "America" category would include the strings "Chicago", "Kentucky/Monticello", and "New_York". In scalar context, it returns an array reference, while in list context it returns an array. =head2 DateTime::TimeZone->countries() Returns a sorted list of all the valid country codes (in lower-case) which can be passed to C. In scalar context, it returns an array reference, while in list context it returns an array. If you need to convert country codes to names or vice versa you can use C to do so. Note that one of the codes returned is "uk", which is an alias for the country code "gb", and is not a valid ISO country code. =head2 DateTime::TimeZone->names_in_country( $country_code ) Given a two-letter ISO3166 country code, this method returns a list of time zones used in that country. The country code may be of any case. In scalar context, it returns an array reference, while in list context it returns an array. This list is returned in an order vaguely based on geography and population. In general, the least used zones come last, but there are not guarantees of a specific order from one release to the next. This order is probably the best option for presenting zones names to end users. =head2 DateTime::TimeZone->offset_as_seconds( $offset ) Given an offset as a string, this returns the number of seconds represented by the offset as a positive or negative number. Returns C if $offset is not in the range C<-99:59:59> to C<+99:59:59>. The offset is expected to match either C or C. If it doesn't match either of these, C will be returned. This means that if you want to specify hours as a single digit, then each element of the offset must be separated by a colon (:). =head2 DateTime::TimeZone->offset_as_string( $offset, $sep ) Given an offset as a number, this returns the offset as a string. Returns C if $offset is not in the range C<-359999> to C<359999>. You can also provide an optional separator which will go between the hours, minutes, and seconds (if applicable) portions of the offset. =head2 Storable Hooks This module provides freeze and thaw hooks for C so that the huge data structures for Olson time zones are not actually stored in the serialized structure. If you subclass C, you will inherit its hooks, which may not work for your module, so please test the interaction of your module with Storable. =head1 LOADING TIME ZONES IN A PRE-FORKING SYSTEM If you are running an application that does pre-forking (for example with Starman), then you should try to load all the time zones that you'll need in the parent process. Time zones are loaded on-demand, so loading them once in each child will waste memory that could otherwise be shared. =head1 CREDITS This module was inspired by Jesse Vincent's work on Date::ICal::Timezone, and written with much help from the datetime@perl.org list. =head1 SEE ALSO datetime@perl.org mailing list The tools directory of the DateTime::TimeZone distribution includes two scripts that may be of interest to some people. They are parse_olson and tests_from_zdump. Please run them with the --help flag to see what they can be used for. =head1 SUPPORT Support for this module is provided via the datetime@perl.org email list. Bugs may be submitted at L. =head1 SOURCE The source code repository for DateTime-TimeZone can be found at L. =head1 DONATIONS If you'd like to thank me for the work I've done on this module, please consider making a "donation" to me via PayPal. I spend a lot of free time creating free software, and would appreciate any support you'd care to offer. Please note that B in order for me to continue working on this particular software. I will continue to do so, inasmuch as I have in the past, for as long as it interests me. Similarly, a donation made in this way will probably not make me work on this software much more, unless I get so many donations that I can consider working on free software full time (let's all have a chuckle at that together). To donate, log into PayPal and send money to autarch@urth.org, or use the button at L. =head1 AUTHOR Dave Rolsky =head1 CONTRIBUTORS =for stopwords Alexey Molchanov Alfie John Andrew Paprocki Brian Fraser Bron Gondwana Daisuke Maki David Pinkowitz Iain Truskett Jakub Wilk James E Keenan Joshua Hoblitt Karen Etheridge karupanerura kclaggett Matthew Horsfall Mohammad S Anwar Olaf Alders Peter Rabbitson Tom Wyant =over 4 =item * Alexey Molchanov =item * Alfie John =item * Andrew Paprocki =item * Brian Fraser =item * Bron Gondwana =item * Daisuke Maki =item * David Pinkowitz =item * Iain Truskett =item * Jakub Wilk =item * James E Keenan =item * Joshua Hoblitt =item * Karen Etheridge =item * karupanerura =item * kclaggett =item * Matthew Horsfall =item * Mohammad S Anwar =item * Olaf Alders =item * Peter Rabbitson =item * Tom Wyant =back =head1 COPYRIGHT AND LICENSE This software is copyright (c) 2024 by Dave Rolsky. This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself. The full text of the license can be found in the F file included with this distribution. =cut