File Coverage

blib/lib/Time/Zone/Olson.pm

Criterion	Covered	Total	%
statement	766	825	92.8
branch	198	258	76.7
condition	46	91	50.5
subroutine	109	110	99.0
pod	16	16	100.0
total	1135	1300	87.3

package Time::Zone::Olson;

use 5.010;
use strict;
use warnings;

use FileHandle();
use File::Spec();
use Config;
use Carp();
use English qw( -no_match_vars );
use DirHandle();
use POSIX();

our $VERSION = '0.12';

sub _SIZE_OF_TZ_HEADER                     { return 44 }
sub _SIZE_OF_TRANSITION_TIME_V1            { return 4 }
sub _SIZE_OF_TRANSITION_TIME_V2            { return 8 }
sub _SIZE_OF_TTINFO                        { return 6 }
sub _SIZE_OF_LEAP_SECOND_V1                { return 4 }
sub _SIZE_OF_LEAP_SECOND_V2                { return 8 }
sub _PAIR                                  { return 2 }
sub _STAT_MTIME_IDX                        { return 9 }
sub _MAX_LENGTH_FOR_TRAILING_TZ_DEFINITION { return 256 }
sub _MONTHS_IN_ONE_YEAR                    { return 12 }
sub _HOURS_IN_ONE_DAY                      { return 24 }
sub _MINUTES_IN_ONE_HOUR                   { return 60 }
sub _SECONDS_IN_ONE_MINUTE                 { return 60 }
sub _SECONDS_IN_ONE_HOUR                   { return 3_600 }
sub _SECONDS_IN_ONE_DAY                    { return 86_400 }
sub _NEGATIVE_ONE                          { return -1 }
sub _LOCALTIME_ISDST_INDEX                 { return 8 }
sub _LOCALTIME_DAY_OF_WEEK_INDEX           { return 6 }
sub _LOCALTIME_YEAR_INDEX                  { return 5 }
sub _LOCALTIME_MONTH_INDEX                 { return 4 }
sub _LOCALTIME_DAY_INDEX                   { return 3 }
sub _LOCALTIME_HOUR_INDEX                  { return 2 }
sub _LOCALTIME_MINUTE_INDEX                { return 1 }
sub _LOCALTIME_SECOND_INDEX                { return 0 }
sub _LOCALTIME_BASE_YEAR                   { return 1900 }
sub _EPOCH_YEAR                            { return 1970 }
sub _EPOCH_WDAY                            { return 4 }
sub _DAYS_IN_JANUARY                       { return 31 }
sub _DAYS_IN_FEBRUARY_LEAP_YEAR            { return 29 }
sub _DAYS_IN_FEBRUARY_NON_LEAP             { return 28 }
sub _DAYS_IN_MARCH                         { return 31 }
sub _DAYS_IN_APRIL                         { return 30 }
sub _DAYS_IN_MAY                           { return 31 }
sub _DAYS_IN_JUNE                          { return 30 }
sub _DAYS_IN_JULY                          { return 31 }
sub _DAYS_IN_AUGUST                        { return 31 }
sub _DAYS_IN_SEPTEMBER                     { return 30 }
sub _DAYS_IN_OCTOBER                       { return 31 }
sub _DAYS_IN_NOVEMBER                      { return 30 }
sub _DAYS_IN_DECEMBER                      { return 31 }
sub _DAYS_IN_A_LEAP_YEAR                   { return 366 }
sub _DAYS_IN_A_NON_LEAP_YEAR               { return 365 }
sub _LAST_WEEK_VALUE                       { return 5 }
sub _LOCALTIME_WEEKDAY_HIGHEST_VALUE       { return 6 }
sub _DAYS_IN_ONE_WEEK                      { return 7 }
sub _EVERY_FOUR_HUNDRED_YEARS              { return 400 }
sub _EVERY_FOUR_YEARS                      { return 4 }
sub _EVERY_ONE_HUNDRED_YEARS               { return 100 }
sub _DEFAULT_DST_START_HOUR                { return 2 }
sub _DEFAULT_DST_END_HOUR                  { return 2 }

sub _TIMEZONE_FULL_NAME_REGEX {
    return qr/(?\w+)(?:\/(?[\w\-\/+]+))?/smx;
}

my $_default_zoneinfo_directory = '/usr/share/zoneinfo';
if ( -e $_default_zoneinfo_directory ) {
}
else {
    if ( -e '/usr/lib/zoneinfo' ) {
        $_default_zoneinfo_directory = '/usr/lib/zoneinfo';
    }
}
my $_zonetab_cache = {};
my $_tzdata_cache  = {};

sub _DEFAULT_ZONEINFO_DIRECTORY { return $_default_zoneinfo_directory }

sub new {
    my ( $class, $params ) = @_;
    my $self = {};
    bless $self, $class;
    $self->directory( $params->{directory}
          || $ENV{TZDIR}
          || _DEFAULT_ZONEINFO_DIRECTORY() );
    if ( defined $params->{offset} ) {
        $self->offset( $params->{offset} );
    }
    else {
        $self->timezone( $params->{timezone} || $ENV{TZ} );
    }
    return $self;
}

sub directory {
    my ( $self, $new ) = @_;
    my $old = $self->{directory};
    if ( @_ > 1 ) {
        $self->{directory} = $new;
    }
    return $old;
}

sub offset {
    my ( $self, $new ) = @_;
    my $old = $self->{offset};
    if ( @_ > 1 ) {
        $self->{offset} = $new;
        delete $self->{tz};
    }
    return $old;
}

sub equiv {
    my ( $self, $time_zone, $from_time ) = @_;
    $from_time //= time;
    my $class = ref $self;
    my $compare = $class->new( { 'timezone' => $time_zone } );
    my %offsets_compare;
    foreach my $transition_time ( $compare->transition_times() ) {
        if ( $transition_time >= $from_time ) {
            $offsets_compare{$transition_time} =
              $compare->local_offset($transition_time);
        }
    }
    my %offsets_self;
    foreach my $transition_time ( $self->transition_times() ) {
        if ( $transition_time >= $from_time ) {
            $offsets_self{$transition_time} =
              $self->local_offset($transition_time);
        }
    }
    if ( scalar keys %offsets_compare == scalar keys %offsets_self ) {
        foreach my $transition_time ( sort { $a <=> $b } keys %offsets_compare )
        {
            if (
                ( defined $offsets_self{$transition_time} )
                && ( $offsets_self{$transition_time} ==
                    $offsets_compare{$transition_time} )
              )
            {
            }
            else {
                return;
            }
        }
        return 1;
    }
    return;
}

sub _timezones {
    my ($self) = @_;
    my $path = File::Spec->catfile( $self->directory(), 'zone.tab' );
    my $handle = FileHandle->new($path)
      or Carp::croak("Failed to open $path for reading:$EXTENDED_OS_ERROR");
    my @stat = stat $handle
      or Carp::croak("Failed to stat $path:$EXTENDED_OS_ERROR");
    my $last_modified = $stat[ _STAT_MTIME_IDX() ];
    if (   ( $self->{_zonetab_last_modified} )
        && ( $self->{_zonetab_last_modified} == $last_modified ) )
    {
    }
    elsif (( $_zonetab_cache->{_zonetab_last_modified} )
        && ( $_zonetab_cache->{_zonetab_last_modified} == $last_modified ) )
    {

        foreach my $key (qw(_zonetab_last_modified _comments _zones)) {
            $self->{$key} = $_zonetab_cache->{$key};
        }
    }
    else {
        $self->{_zones}    = [];
        $self->{_comments} = {};
        while ( my $line = <$handle> ) {
            next if ( $line =~ /^[#]/smx );
            chomp $line;
            my ( $country_code, $coordinates, $timezone, $comment ) =
              split /\t/smx, $line;
            push @{ $self->{_zones} }, $timezone;
            $self->{_comments}->{$timezone} = $comment;
        }
        close $handle
          or Carp::croak("Failed to close $path:$EXTENDED_OS_ERROR");
        $self->{_zonetab_last_modified} = $last_modified;
        foreach my $key (qw(_zonetab_last_modified _comments _zones)) {
            $_zonetab_cache->{$key} = $self->{$key};
        }
    }
    my @sorted_zones = sort { $a cmp $b } @{ $self->{_zones} };
    return @sorted_zones;
}

sub areas {
    my ($self) = @_;
    my %areas;
    foreach my $timezone ( $self->_timezones() ) {
        my $timezone_full_name_regex = _TIMEZONE_FULL_NAME_REGEX();
        if ( $timezone =~ /^$timezone_full_name_regex$/smx ) {
            $areas{ $LAST_PAREN_MATCH{area} } = 1;
        }
        else {
            Carp::croak(
                "'$timezone' does not have a valid format for a TZ timezone");
        }
    }
    my @sorted_areas = sort { $a cmp $b } keys %areas;
    return @sorted_areas;
}

sub locations {
    my ( $self, $area ) = @_;
    if ( !length $area ) {
        return ();
    }
    my %locations;
    foreach my $timezone ( $self->_timezones() ) {
        my $timezone_full_name_regex = _TIMEZONE_FULL_NAME_REGEX();
        if ( $timezone =~ /^$timezone_full_name_regex$/smx ) {
            if (   ( $area eq $LAST_PAREN_MATCH{area} )
                && ( $LAST_PAREN_MATCH{location} ) )
            {
                $locations{ $LAST_PAREN_MATCH{location} } = 1;
            }
        }
        else {
            Carp::croak(
                "'$timezone' does not have a valid format for a TZ timezone");
        }
    }
    my @sorted_locations = sort { $a cmp $b } keys %locations;
    return @sorted_locations;
}

sub comment {
    my ( $self, $tz ) = @_;
    $tz ||= $self->timezone();
    $self->_timezones();
    if ( defined $self->{_comments}->{$tz} ) {
        return $self->{_comments}->{$tz};
    }
    else {
        return;
    }
}

sub area {
    my ($self) = @_;
    return $self->{area};
}

sub location {
    my ($self) = @_;
    return $self->{location};
}

sub timezone {
    my ( $self, $new ) = @_;
    my $old = $self->{tz};
    if ( @_ > 1 ) {
        if ( defined $new ) {
            my $timezone_full_name_regex = _TIMEZONE_FULL_NAME_REGEX();
            if ( $new !~ /^$timezone_full_name_regex$/smx ) {
                Carp::croak(
                    "'$new' does not have a valid format for a TZ timezone");
            }
            $self->{area}     = $LAST_PAREN_MATCH{area};
            $self->{location} = $LAST_PAREN_MATCH{location};
            my $path = File::Spec->catfile( $self->directory(), $new );
            if ( !-f $path ) {
                Carp::croak(
                    "'$new' is not an timezone in the existing Olson database");
            }
        }
        $self->{tz} = $new;
        delete $self->{offset};
    }
    return $old;
}

sub _is_leap_year {
    my ( $self, $year ) = @_;
    my $leap_year;
    if (
        ( $year % _EVERY_FOUR_HUNDRED_YEARS() == 0 )
        || (   ( $year % _EVERY_FOUR_YEARS() == 0 )
            && ( $year % _EVERY_ONE_HUNDRED_YEARS() != 0 ) )
      )
    {
        $leap_year = 1;
    }
    else {
        $leap_year = 0;
    }
    return $leap_year;
}

sub _in_dst_according_to_tz {
    my ( $self, $check_time, $tz_definition ) = @_;

    if (   ( defined $tz_definition->{start_day} )
        && ( defined $tz_definition->{end_day} )
        && ( defined $tz_definition->{start_week} )
        && ( defined $tz_definition->{end_week} )
        && ( defined $tz_definition->{start_month} )
        && ( defined $tz_definition->{end_month} ) )
    {
        my $check_year =
          ( $self->_gm_time($check_time) )[ _LOCALTIME_YEAR_INDEX() ] +
          _LOCALTIME_BASE_YEAR();
        my $dst_start_time = $self->_get_time_for_wday_week_month_year(
            $tz_definition->{start_day},   $tz_definition->{start_week},
            $tz_definition->{start_month}, $check_year
          ) +
          ( $tz_definition->{start_hour} *
              _SECONDS_IN_ONE_MINUTE() *
              _MINUTES_IN_ONE_HOUR() ) +
          ( $tz_definition->{start_minute} * _SECONDS_IN_ONE_MINUTE() ) +
          $tz_definition->{start_second} -
          $tz_definition->{std_offset_in_seconds};
        my $dst_end_time = $self->_get_time_for_wday_week_month_year(
            $tz_definition->{end_day},   $tz_definition->{end_week},
            $tz_definition->{end_month}, $check_year
          ) +
          ( $tz_definition->{end_hour} *
              _SECONDS_IN_ONE_MINUTE() *
              _MINUTES_IN_ONE_HOUR() ) +
          ( $tz_definition->{end_minute} * _SECONDS_IN_ONE_MINUTE() ) +
          $tz_definition->{end_second} -
          $tz_definition->{dst_offset_in_seconds};

        if ( $dst_start_time < $dst_end_time ) {
            if (   ( $dst_start_time < $check_time )
                && ( $check_time < $dst_end_time ) )
            {
                return 1;
            }
        }
        else {
            if (   ( $check_time < $dst_start_time )
                || ( $dst_end_time < $check_time ) )
            {
                return 1;
            }
        }
    }

    return 0;
}

sub _get_time_for_wday_week_month_year {
    my ( $self, $wday, $week, $month, $year ) = @_;

    my $check_year = _EPOCH_YEAR();
    my $time       = 0;
    my $increment  = 0;
    my $leap_year  = 1;
    while ( $check_year < $year ) {
        $check_year += 1;
        if ( $self->_is_leap_year($check_year) ) {
            $leap_year = 1;
            $increment = _DAYS_IN_A_LEAP_YEAR() * _SECONDS_IN_ONE_DAY();
        }
        else {
            $leap_year = 0;
            $increment = _DAYS_IN_A_NON_LEAP_YEAR() * _SECONDS_IN_ONE_DAY();
        }
        $time += $increment;
    }

    $increment = 0;
    my $check_month   = 1;
    my @days_in_month = $self->_days_in_month($leap_year);
    while ( $check_month < $month ) {

        $increment = $days_in_month[ $check_month - 1 ] * _SECONDS_IN_ONE_DAY();
        $time += $increment;
        $check_month += 1;
    }

    if ( $week == _LAST_WEEK_VALUE() ) {
        $time +=
          ( $days_in_month[ $check_month - 1 ] - 1 ) * _SECONDS_IN_ONE_DAY();
        my $check_day_of_week =
          ( $self->_gm_time($time) )[ _LOCALTIME_DAY_OF_WEEK_INDEX() ];

        while ( $check_day_of_week != $wday ) {

            $time -= _SECONDS_IN_ONE_DAY;
            $check_day_of_week -= 1;
            if ( $check_day_of_week < 0 ) {
                $check_day_of_week = _LOCALTIME_WEEKDAY_HIGHEST_VALUE();
            }
        }
    }
    else {
        my $check_day_of_week =
          ( $self->_gm_time($time) )[ _LOCALTIME_DAY_OF_WEEK_INDEX() ];
        my $check_week = 1;
        $increment = _DAYS_IN_ONE_WEEK() * _SECONDS_IN_ONE_DAY();
        while ( $check_week < $week ) {
            $check_week += 1;
            $time += $increment;
        }

        while ( $check_day_of_week != $wday ) {

            $time += _SECONDS_IN_ONE_DAY();
            $check_day_of_week += 1;
            $check_day_of_week = $check_day_of_week % _DAYS_IN_ONE_WEEK();
        }
    }

    return $time;
}

sub _get_tz_offset_according_to_v2_tz_rule {
    my ( $self, $time ) = @_;
    if ( defined $self->offset() ) {
        return ( 0, $self->offset() * _SECONDS_IN_ONE_MINUTE(), q[] );
    }
    my $tz = $self->timezone();
    my ( $isdst, $gmtoff, $abbr );
    my $tz_definition = $self->{_tzdata}->{$tz}->{tz_definition};
    if ( defined $tz_definition->{std_name} ) {
        if ( defined $tz_definition->{dst_name} ) {
            if ( $self->_in_dst_according_to_tz( $time, $tz_definition ) ) {
                $isdst  = 1;
                $gmtoff = $tz_definition->{dst_offset_in_seconds};
                $abbr   = $tz_definition->{dst_name};
            }
            else {
                $isdst  = 0;
                $gmtoff = $tz_definition->{std_offset_in_seconds};
                $abbr   = $tz_definition->{std_name};
            }
        }
        else {
            $isdst  = 0;
            $gmtoff = $tz_definition->{std_offset_in_seconds};
            $abbr   = $tz_definition->{std_name};
        }
    }
    return ( $isdst, $gmtoff, $abbr );
}

sub _negative_gm_time {
    my ( $self, $time ) = @_;
    my $year           = _EPOCH_YEAR() - 1;
    my $wday           = _EPOCH_WDAY() - 1;
    my $check_time     = 0;
    my $number_of_days = 0;
    my $leap_year;
  YEAR: while (1) {
        $leap_year      = $self->_is_leap_year($year);
        $number_of_days = $self->_number_of_days_in_a_year($leap_year);
        my $increment = $number_of_days * _SECONDS_IN_ONE_DAY();
        if ( $check_time - $increment > $time ) {
            $check_time -= $increment;
            $wday       -= $number_of_days;
            $year       -= 1;
        }
        else {
            last YEAR;
        }
    }
    my $yday = $self->_number_of_days_in_a_year($leap_year);
    $year -= _LOCALTIME_BASE_YEAR();

    my $month         = _MONTHS_IN_ONE_YEAR();
    my @days_in_month = $self->_days_in_month($leap_year);
  MONTH: while (1) {

        $number_of_days = $days_in_month[ $month - 1 ];
        my $increment = $number_of_days * _SECONDS_IN_ONE_DAY();
        if ( $check_time - $increment > $time ) {
            $check_time -= $increment;
            $wday       -= $number_of_days;
            $yday       -= $number_of_days;
            $month      -= 1;
        }
        else {
            last MONTH;
        }
    }
    $month -= 1;

    my $day       = $days_in_month[$month];
    my $increment = _SECONDS_IN_ONE_DAY();
  DAY: while (1) {
        if ( $check_time - $increment > $time ) {
            $check_time -= $increment;
            $day        -= 1;
            $yday       -= 1;
            $wday       -= 1;
        }
        else {
            last DAY;
        }
    }

    $wday = abs $wday % _DAYS_IN_ONE_WEEK();

    my $hour = _HOURS_IN_ONE_DAY() - 1;
    $increment = _SECONDS_IN_ONE_HOUR();
  HOUR: while (1) {
        if ( $check_time - $increment > $time ) {
            $check_time -= $increment;
            $hour -= 1;
        }
        else {
            last HOUR;
        }
    }
    my $minute = _MINUTES_IN_ONE_HOUR() - 1;
    $increment = _SECONDS_IN_ONE_MINUTE();
  MINUTE: while (1) {
        if ( $check_time - $increment > $time ) {
            $check_time -= $increment;
            $minute -= 1;
        }
        else {
            last MINUTE;
        }
    }
    my $seconds = _SECONDS_IN_ONE_MINUTE() - ( $check_time - $time );

    return ( $seconds, $minute, $hour, $day, $month, "$year", $wday, $yday, 0 );
}

sub _positive_gm_time {
    my ( $self, $time ) = @_;
    my $year           = _EPOCH_YEAR();
    my $wday           = _EPOCH_WDAY();
    my $check_time     = 0;
    my $number_of_days = 0;
    my $leap_year;
  YEAR: while (1) {
        $leap_year      = $self->_is_leap_year($year);
        $number_of_days = $self->_number_of_days_in_a_year($leap_year);
        my $increment = $number_of_days * _SECONDS_IN_ONE_DAY();
        if ( $check_time + $increment <= $time ) {
            $check_time += $increment;
            $wday       += $number_of_days;
            $year       += 1;
        }
        else {
            last YEAR;
        }
    }
    $year -= _LOCALTIME_BASE_YEAR();

    my $month         = 0;
    my @days_in_month = $self->_days_in_month($leap_year);
    my $yday          = 0;
  MONTH: while (1) {

        $number_of_days = $days_in_month[$month];
        my $increment = $number_of_days * _SECONDS_IN_ONE_DAY();
        if ( $check_time + $increment <= $time ) {
            $check_time += $increment;
            $wday       += $number_of_days;
            $yday       += $number_of_days;
            $month      += 1;
        }
        else {
            last MONTH;
        }
    }
    my $day       = 1;
    my $increment = _SECONDS_IN_ONE_DAY();
  DAY: while (1) {
        if ( $check_time + $increment <= $time ) {
            $check_time += $increment;
            $day        += 1;
            $yday       += 1;
            $wday       += 1;
        }
        else {
            last DAY;
        }
    }

    $wday = $wday % _DAYS_IN_ONE_WEEK();

    my $hour = 0;
    $increment = _SECONDS_IN_ONE_HOUR();
  HOUR: while (1) {
        if ( $check_time + $increment <= $time ) {
            $check_time += $increment;
            $hour += 1;
        }
        else {
            last HOUR;
        }
    }
    my $minute = 0;
    $increment = _SECONDS_IN_ONE_MINUTE();
  MINUTE: while (1) {
        if ( $check_time + $increment <= $time ) {
            $check_time += $increment;
            $minute += 1;
        }
        else {
            last MINUTE;
        }
    }
    my $seconds = $time - $check_time;

    return ( $seconds, $minute, $hour, $day, $month, "$year", $wday, $yday, 0 );
}

sub _gm_time {
    my ( $self, $time ) = @_;
    my @gmtime;
    if ( $time < 0 ) {
        @gmtime = $self->_negative_gm_time($time);
    }
    else {
        @gmtime = $self->_positive_gm_time($time);
    }
    if (wantarray) {
        return @gmtime;
    }
    else {
        return POSIX::strftime( '%a %b %e %H:%M:%S %Y', @gmtime );
    }
}

sub time_local {
    my ( $self, @localtime ) = @_;
    my $time = 0;
    $localtime[ _LOCALTIME_YEAR_INDEX() ] += _LOCALTIME_BASE_YEAR();
    if ( $localtime[ _LOCALTIME_YEAR_INDEX() ] >= _EPOCH_YEAR() ) {
        return $self->_positive_time_local(@localtime);
    }
    else {
        return $self->_negative_time_local(@localtime);
    }
}

sub _positive_time_local {
    my ( $self, @localtime ) = @_;
    my $check_year = _EPOCH_YEAR();
    my $wday       = _EPOCH_WDAY();
    my $time       = 0;
    my $leap_year  = 0;
  YEAR: while (1) {

        if ( $check_year < $localtime[ _LOCALTIME_YEAR_INDEX() ] ) {
            $time += $self->_number_of_days_in_a_year($leap_year) *
              _SECONDS_IN_ONE_DAY();
            $check_year += 1;
            $leap_year = $self->_is_leap_year($check_year);
        }
        else {
            last YEAR;
        }
    }

    my $check_month   = 0;
    my @days_in_month = $self->_days_in_month($leap_year);
  MONTH: while (1) {

        if ( $check_month < $localtime[ _LOCALTIME_MONTH_INDEX() ] ) {
            $time += $days_in_month[$check_month] * _SECONDS_IN_ONE_DAY();
            $check_month += 1;
        }
        else {
            last MONTH;
        }
    }
    my $check_day = 1;
  DAY: while (1) {
        if ( $check_day < $localtime[ _LOCALTIME_DAY_INDEX() ] ) {
            $time += _SECONDS_IN_ONE_DAY();
            $check_day += 1;
        }
        else {
            last DAY;
        }
    }

    $wday = $wday % _DAYS_IN_ONE_WEEK();

    my $check_hour = 0;
  HOUR: while (1) {
        if ( $check_hour < $localtime[ _LOCALTIME_HOUR_INDEX() ] ) {
            $time += _SECONDS_IN_ONE_HOUR();
            $check_hour += 1;
        }
        else {
            last HOUR;
        }
    }
    my $check_minute = 0;
  MINUTE: while (1) {
        if ( $check_minute < $localtime[ _LOCALTIME_MINUTE_INDEX() ] ) {
            $time += _SECONDS_IN_ONE_MINUTE();
            $check_minute += 1;
        }
        else {
            last MINUTE;
        }
    }
    $time += $localtime[ _LOCALTIME_SECOND_INDEX() ];
    my ( $isdst, $gmtoff, $abbr ) =
      $self->_get_isdst_gmtoff_abbr_calculating_for_time_local($time);
    $time -= $gmtoff;

    return $time;
}

sub _days_in_month {
    my ( $self, $leap_year ) = @_;
    return (
        _DAYS_IN_JANUARY(),
        (
            $leap_year
            ? _DAYS_IN_FEBRUARY_LEAP_YEAR()
            : _DAYS_IN_FEBRUARY_NON_LEAP()
        ),
        _DAYS_IN_MARCH(),
        _DAYS_IN_APRIL(),
        _DAYS_IN_MAY(),
        _DAYS_IN_JUNE(),
        _DAYS_IN_JULY(),
        _DAYS_IN_AUGUST(),
        _DAYS_IN_SEPTEMBER(),
        _DAYS_IN_OCTOBER(),
        _DAYS_IN_NOVEMBER(),
        _DAYS_IN_DECEMBER(),
    );
}

sub _number_of_days_in_a_year {
    my ( $self, $leap_year ) = @_;
    if ($leap_year) {
        return _DAYS_IN_A_LEAP_YEAR();
    }
    else {
        return _DAYS_IN_A_NON_LEAP_YEAR();
    }
}

sub _negative_time_local {
    my ( $self, @localtime ) = @_;
    my $check_year = _EPOCH_YEAR() - 1;
    my $wday       = _EPOCH_WDAY();
    my $time       = 0;
    my $leap_year;
  YEAR: while (1) {

        if ( $check_year > $localtime[ _LOCALTIME_YEAR_INDEX() ] ) {
            $time -= $self->_number_of_days_in_a_year($leap_year) *
              _SECONDS_IN_ONE_DAY();
            $check_year -= 1;
            $leap_year = $self->_is_leap_year($check_year);
        }
        else {
            last YEAR;
        }
    }

    my $check_month   = _MONTHS_IN_ONE_YEAR() - 1;
    my @days_in_month = $self->_days_in_month($leap_year);
  MONTH: while (1) {

        if ( $check_month > $localtime[ _LOCALTIME_MONTH_INDEX() ] ) {
            $time -= $days_in_month[$check_month] * _SECONDS_IN_ONE_DAY();
            $check_month -= 1;
        }
        else {
            last MONTH;
        }
    }
    my $check_day = $days_in_month[$check_month];
  DAY: while (1) {
        if ( $check_day > $localtime[ _LOCALTIME_DAY_INDEX() ] ) {
            $time -= _SECONDS_IN_ONE_DAY();
            $check_day -= 1;
        }
        else {
            last DAY;
        }
    }

    $wday = $wday % _DAYS_IN_ONE_WEEK();

    my $check_hour = _HOURS_IN_ONE_DAY() - 1;
  HOUR: while (1) {
        if ( $check_hour > $localtime[ _LOCALTIME_HOUR_INDEX() ] ) {
            $time -= _SECONDS_IN_ONE_HOUR();
            $check_hour -= 1;
        }
        else {
            last HOUR;
        }
    }
    my $check_minute = _MINUTES_IN_ONE_HOUR();
  MINUTE: while (1) {
        if ( $check_minute > $localtime[ _LOCALTIME_MINUTE_INDEX() ] ) {
            $time -= _SECONDS_IN_ONE_MINUTE();
            $check_minute -= 1;
        }
        else {
            last MINUTE;
        }
    }
    $time += $localtime[ _LOCALTIME_SECOND_INDEX() ];
    my ( $isdst, $gmtoff, $abbr ) =
      $self->_get_isdst_gmtoff_abbr_calculating_for_time_local($time);
    $time -= $gmtoff;

    return $time;
}

sub _get_first_standard_time_type {
    my ( $self, $tz ) = @_;
    my $first_standard_time_type;
    if ( defined $self->{_tzdata}->{$tz}->{local_time_types}->[0] ) {
        $first_standard_time_type =
          $self->{_tzdata}->{$tz}->{local_time_types}->[0];
    }
  FIRST_STANDARD_TIME_TYPE:
    foreach
      my $local_time_type ( @{ $self->{_tzdata}->{$tz}->{local_time_types} } )
    {
        if ( $local_time_type->{isdst} ) {
        }
        else {
            $first_standard_time_type = $local_time_type;
            last FIRST_STANDARD_TIME_TYPE;
        }
    }
    return $first_standard_time_type;
}

sub _get_isdst_gmtoff_abbr_calculating_for_time_local {
    my ( $self, $time ) = @_;
    if ( defined $self->offset() ) {
        return ( 0, $self->offset() * _SECONDS_IN_ONE_MINUTE(), q[] );
    }
    my ( $isdst, $gmtoff, $abbr );
    my $tz = $self->timezone();
    $self->_read_tzfile();
    my $first_standard_time_type = $self->_get_first_standard_time_type($tz);
    my $transition_index         = 0;
    my $transition_time_found;
    my $previous_offset = $first_standard_time_type->{gmtoff};
    my $first_transition_time;
  TRANSITION_TIME:

    foreach my $transition_time_in_gmt ( $self->transition_times() ) {

        if ( !defined $first_transition_time ) {
            $first_transition_time = $transition_time_in_gmt;
        }
        my $local_time_index =
          $self->{_tzdata}->{$tz}->{local_time_indexes}->[$transition_index];
        my $local_time_type =
          $self->{_tzdata}->{$tz}->{local_time_types}->[$local_time_index];
        if ( $local_time_type->{gmtoff} < $previous_offset ) {
            if (
                ( $transition_time_in_gmt > $time - $previous_offset )
                && ( $transition_time_in_gmt <=
                    $time - $local_time_type->{gmtoff} )
              )
            {
                $transition_time_found = 1;
                last TRANSITION_TIME;
            }
            elsif (
                $transition_time_in_gmt > $time - $local_time_type->{gmtoff} )
            {
                $transition_time_found = 1;
                last TRANSITION_TIME;
            }
        }
        else {
            if ( $transition_time_in_gmt > $time - $local_time_type->{gmtoff} )
            {
                $transition_time_found = 1;
                last TRANSITION_TIME;
            }
        }
        $transition_index += 1;
        $previous_offset = $local_time_type->{gmtoff};
    }
    my $offset_found;
    if (
           ( defined $first_transition_time )
        && ($first_standard_time_type)
        && ( $time <
            $first_transition_time + $first_standard_time_type->{gmtoff} )
      )
    {
        $gmtoff       = $first_standard_time_type->{gmtoff};
        $isdst        = $first_standard_time_type->{isdst};
        $abbr         = $first_standard_time_type->{abbr};
        $offset_found = 1;
    }
    elsif ( !$transition_time_found ) {
        ( $isdst, $gmtoff, $abbr ) =
          $self->_get_tz_offset_according_to_v2_tz_rule($time);
        if ( defined $gmtoff ) {
            $offset_found = 1;
        }
    }
    if ($offset_found) {
    }
    elsif (
        defined $self->{_tzdata}->{$tz}->{local_time_indexes}
        ->[ $transition_index - 1 ] )
    {
        my $local_time_index = $self->{_tzdata}->{$tz}->{local_time_indexes}
          ->[ $transition_index - 1 ];
        my $local_time_type =
          $self->{_tzdata}->{$tz}->{local_time_types}->[$local_time_index];
        $gmtoff = $local_time_type->{gmtoff};
        $isdst  = $local_time_type->{isdst};
        $abbr   = $local_time_type->{abbr};
    }
    else {
        $gmtoff = $first_standard_time_type->{gmtoff};
        $isdst  = $first_standard_time_type->{isdst};
        $abbr   = $first_standard_time_type->{abbr};
    }
    return ( $isdst, $gmtoff, $abbr );
}

sub _get_isdst_gmtoff_abbr_calculating_for_local_time {
    my ( $self, $time ) = @_;
    my ( $isdst, $gmtoff, $abbr );
    if ( defined $self->offset() ) {
        return ( 0, $self->offset() * _SECONDS_IN_ONE_MINUTE(), q[] );
    }
    my $tz = $self->timezone();
    $self->_read_tzfile();
    my $transition_index = 0;
    my $transition_time_found;
    my $first_transition_time;
  TRANSITION_TIME:
    foreach my $transition_time_in_gmt ( $self->transition_times() ) {

        if ( !defined $first_transition_time ) {
            $first_transition_time = $transition_time_in_gmt;
        }
        if ( $transition_time_in_gmt > $time ) {
            $transition_time_found = 1;
            last TRANSITION_TIME;
        }
        $transition_index += 1;
    }
    my $first_standard_time_type = $self->_get_first_standard_time_type($tz);
    my $offset_found;
    if (   ( defined $first_transition_time )
        && ( $time < $first_transition_time ) )
    {
        $gmtoff       = $first_standard_time_type->{gmtoff};
        $isdst        = $first_standard_time_type->{isdst};
        $abbr         = $first_standard_time_type->{abbr};
        $offset_found = 1;
    }
    elsif ( !$transition_time_found ) {
        ( $isdst, $gmtoff, $abbr ) =
          $self->_get_tz_offset_according_to_v2_tz_rule($time);
        if ( defined $gmtoff ) {
            $offset_found = 1;
        }
    }
    if ($offset_found) {
    }
    elsif (
        defined $self->{_tzdata}->{$tz}->{local_time_indexes}
        ->[ $transition_index - 1 ] )
    {
        my $local_time_index = $self->{_tzdata}->{$tz}->{local_time_indexes}
          ->[ $transition_index - 1 ];
        my $local_time_type =
          $self->{_tzdata}->{$tz}->{local_time_types}->[$local_time_index];
        $gmtoff = $local_time_type->{gmtoff};
        $isdst  = $local_time_type->{isdst};
        $abbr   = $local_time_type->{abbr};
    }
    else {
        $gmtoff = $first_standard_time_type->{gmtoff};
        $isdst  = $first_standard_time_type->{isdst};
        $abbr   = $first_standard_time_type->{abbr};
    }
    return ( $isdst, $gmtoff, $abbr );
}

sub local_offset {
    my ( $self, $time ) = @_;
    if ( !defined $time ) {
        $time = time;
    }
    my ( $isdst, $gmtoff, $abbr ) =
      $self->_get_isdst_gmtoff_abbr_calculating_for_local_time($time);
    return int( $gmtoff / _SECONDS_IN_ONE_MINUTE() );
}

sub local_time {
    my ( $self, $time ) = @_;
    if ( !defined $time ) {
        $time = time;
    }

    my ( $isdst, $gmtoff, $abbr ) =
      $self->_get_isdst_gmtoff_abbr_calculating_for_local_time($time);
    $time += $gmtoff;

    if (wantarray) {
        my (@local_time) = $self->_gm_time($time);
        $local_time[ _LOCALTIME_ISDST_INDEX() ] = $isdst;
        return @local_time;
    }
    else {
        return $self->_gm_time($time);
    }
}

sub transition_times {
    my ($self) = @_;
    my $tz = $self->timezone();
    $self->_read_tzfile();
    return @{ $self->{_tzdata}->{$tz}->{transition_times} };
}

sub leap_seconds {
    my ($self) = @_;
    my $tz = $self->timezone();
    $self->_read_tzfile();
    my @leap_seconds =
      sort { $a <=> $b } keys %{ $self->{_tzdata}->{$tz}->{leap_seconds} };
    return @leap_seconds;
}

sub _read_header {
    my ( $self, $handle, $path ) = @_;
    my $result = $handle->read( my $buffer, _SIZE_OF_TZ_HEADER() );
    if ( defined $result ) {
        if ( $result != _SIZE_OF_TZ_HEADER() ) {
            Carp::croak(
"Failed to read entire header from $path.  $result bytes were read instead of the expected "
                  . _SIZE_OF_TZ_HEADER() );
        }
    }
    else {
        Carp::croak("Failed to read header from $path:$EXTENDED_OS_ERROR");
    }
    my ( $magic, $version, $ttisgmtcnt, $ttisstdcnt, $leapcnt, $timecnt,
        $typecnt, $charcnt )
      = unpack 'A4A1x15N!N!N!N!N!N!', $buffer;
    ( $magic eq 'TZif' ) or Carp::croak("$path is not a TZ file");
    my $header = {
        magic      => $magic,
        version    => $version,
        ttisgmtcnt => $ttisgmtcnt,
        ttisstdcnt => $ttisstdcnt,
        leapcnt    => $leapcnt,
        timecnt    => $timecnt,
        typecnt    => $typecnt,
        charcnt    => $charcnt
    };

    return $header;
}

sub _read_transition_times {
    my ( $self, $handle, $path, $timecnt, $sizeof_transition_time ) = @_;
    my $sizeof_transition_times = $timecnt * $sizeof_transition_time;
    my $result = $handle->read( my $buffer, $sizeof_transition_times );
    if ( defined $result ) {
        if ( $result != $sizeof_transition_times ) {
            Carp::croak(
"Failed to read all the transition times from $path.  $result bytes were read instead of the expected "
                  . $sizeof_transition_times );
        }
    }
    else {
        Carp::croak(
            "Failed to read transition times from $path:$EXTENDED_OS_ERROR");
    }
    my @transition_times;
    if ( $sizeof_transition_time == _SIZE_OF_TRANSITION_TIME_V1() ) {
        @transition_times = unpack 'l>' . $timecnt, $buffer;
    }
    elsif ( $sizeof_transition_time == _SIZE_OF_TRANSITION_TIME_V2() ) {
        eval { @transition_times = unpack 'q>' . $timecnt, $buffer; 1; } or do {
            require Math::Int64;
            @transition_times =
              map { Math::Int64::net_to_int64($_) } unpack '(a8)' . $timecnt,
              $buffer;
        };
    }
    return \@transition_times;
}

sub _read_local_time_indexes {
    my ( $self, $handle, $path, $timecnt ) = @_;
    my $result = $handle->read( my $buffer, $timecnt );
    if ( defined $result ) {
        if ( $result != $timecnt ) {
            Carp::croak(
"Failed to read all the local time indexes from $path.  $result bytes were read instead of the expected "
                  . $timecnt );
        }
    }
    else {
        Carp::croak(
            "Failed to read local time indexes from $path:$EXTENDED_OS_ERROR");
    }
    my @local_time_indexes = unpack 'C' . $timecnt, $buffer;
    return \@local_time_indexes;
}

sub _read_local_time_types {
    my ( $self, $handle, $path, $typecnt ) = @_;
    my $sizeof_local_time_types = $typecnt * _SIZE_OF_TTINFO();
    my $result = $handle->read( my $buffer, $sizeof_local_time_types );
    if ( defined $result ) {
        if ( $result != $sizeof_local_time_types ) {
            Carp::croak(
"Failed to read all the local time types from $path.  $result bytes were read instead of the expected "
                  . $sizeof_local_time_types );
        }
    }
    else {
        Carp::croak(
            "Failed to read local time types from $path:$EXTENDED_OS_ERROR");
    }
    my @local_time_types;
    foreach my $local_time_type ( unpack '(a6)' . $typecnt, $buffer ) {
        my ( $c1, $c2, $c3 ) = unpack 'a4aa', $local_time_type;
        my $gmtoff  = unpack 'l>', $c1;
        my $isdst   = unpack 'C',  $c2;
        my $abbrind = unpack 'C',  $c3;
        push @local_time_types,
          { gmtoff => $gmtoff, isdst => $isdst, abbrind => $abbrind };
    }
    return \@local_time_types;
}

sub _read_time_zone_abbreviation_strings {
    my ( $self, $handle, $path, $charcnt ) = @_;
    my $result = $handle->read( my $time_zone_abbreviation_strings, $charcnt );
    if ( defined $result ) {
        if ( $result != $charcnt ) {
            Carp::croak(
"Failed to read all the time zone abbreviations from $path.  $result bytes were read instead of the expected "
                  . $charcnt );
        }
    }
    else {
        Carp::croak(
"Failed to read time zone abbreviations from $path:$EXTENDED_OS_ERROR"
        );
    }
    return $time_zone_abbreviation_strings;
}

sub _read_leap_seconds {
    my ( $self, $handle, $path, $leapcnt, $sizeof_leap_second ) = @_;
    my $sizeof_leap_seconds = $leapcnt * _PAIR() * $sizeof_leap_second;
    my $result = $handle->read( my $buffer, $sizeof_leap_seconds );
    if ( defined $result ) {
        if ( $result != $sizeof_leap_seconds ) {
            Carp::croak(
"Failed to read all the leap seconds from $path.  $result bytes were read instead of the expected "
                  . $sizeof_leap_seconds );
        }
    }
    else {
        Carp::croak(
            "Failed to read leap seconds from $path:$EXTENDED_OS_ERROR");
    }
    my @paired_leap_seconds = unpack 'L>' . $leapcnt, $buffer;
    my %leap_seconds;
    while (@paired_leap_seconds) {
        my $time_leap_second_occurs      = shift @paired_leap_seconds;
        my $total_number_of_leap_seconds = shift @paired_leap_seconds;
        $leap_seconds{$time_leap_second_occurs} = $total_number_of_leap_seconds;
    }
    return \%leap_seconds;
}

sub _read_is_standard_time {
    my ( $self, $handle, $path, $ttisstdcnt ) = @_;
    my $result = $handle->read( my $buffer, $ttisstdcnt );
    if ( defined $result ) {
        if ( $result != $ttisstdcnt ) {
            Carp::croak(
"Failed to read all the is standard time values from $path.  $result bytes were read instead of the expected "
                  . $ttisstdcnt );
        }
    }
    else {
        Carp::croak(
"Failed to read is standard time values from $path:$EXTENDED_OS_ERROR"
        );
    }
    my @is_std_time = unpack 'C' . $ttisstdcnt, $buffer;
    return \@is_std_time;
}

sub _read_is_gmt {
    my ( $self, $handle, $path, $ttisgmtcnt ) = @_;
    my $result = $handle->read( my $buffer, $ttisgmtcnt );
    if ( defined $result ) {
        if ( $result != $ttisgmtcnt ) {
            Carp::croak(
"Failed to read all the is GMT values from $path.  $result bytes were read instead of the expected "
                  . $ttisgmtcnt );
        }
    }
    else {
        Carp::croak(
            "Failed to read is GMT values from $path:$EXTENDED_OS_ERROR");
    }
    my @is_gmt_time = unpack 'C' . $ttisgmtcnt, $buffer;
    return \@is_gmt_time;
}

sub _read_tz_definition {
    my ( $self, $handle, $path ) = @_;
    my $result =
      $handle->read( my $buffer, _MAX_LENGTH_FOR_TRAILING_TZ_DEFINITION() );
    if ( defined $result ) {
        if ( $result == _MAX_LENGTH_FOR_TRAILING_TZ_DEFINITION() ) {
            Carp::croak(
                    "The tz defintion at the end of $path could not be read in "
                  . _MAX_LENGTH_FOR_TRAILING_TZ_DEFINITION()
                  . ' bytes' );
        }
    }
    else {
        Carp::croak(
            "Failed to read tz definition from $path:$EXTENDED_OS_ERROR");
    }
    if ( $buffer =~ /^\n([^\n]+)\n*$/smx ) {
        return $self->_parse_tz_variable( $1, $path );

    }
    return;
}

sub _parse_tz_variable {
    my ( $self, $tz_variable, $path ) = @_;
    my $timezone_abbr_name_regex =
      qr/(?:[^:\d,+-][^\d,+-]{2,}|[<]\w*[+-]?\d+[>])/smx;
    my $std_name_regex = qr/(?$timezone_abbr_name_regex)/smx
      ;    # Name for standard offset from GMT
    my $std_sign_regex    = qr/(?[+-])/smx;
    my $std_hours_regex   = qr/(?\d+)/smx;
    my $std_minutes_regex = qr/(?::(?\d+))/smx;
    my $std_seconds_regex = qr/(?::(?\d+))/smx;
    my $std_offset_regex =
qr/$std_sign_regex?$std_hours_regex$std_minutes_regex?$std_seconds_regex?/smx
      ;    # Standard offset from GMT
    my $dst_name_regex = qr/(?$timezone_abbr_name_regex)/smx
      ;    # Name for daylight saving offset from GMT
    my $dst_sign_regex    = qr/(?[+-])/smx;
    my $dst_hours_regex   = qr/(?\d+)/smx;
    my $dst_minutes_regex = qr/(?::(?\d+))/smx;
    my $dst_seconds_regex = qr/(?::(?\d+))/smx;
    my $dst_offset_regex =
qr/$dst_sign_regex?$dst_hours_regex$dst_minutes_regex?$dst_seconds_regex?/smx
      ;    # Standard offset from GMT
    my $start_julian_without_feb29_regex =
      qr/(?:J(?\d{1,3}))/smx;
    my $start_julian_with_feb29_regex =
      qr/(?\d{1,3})/smx;
    my $start_month_regex = qr/(?\d{1,2})/smx;
    my $start_week_regex  = qr/(?[1-5])/smx;
    my $start_day_regex   = qr/(?[0-6])/smx;
    my $start_month_week_day_regex =
      qr/(?:M$start_month_regex[.]$start_week_regex[.]$start_day_regex)/smx;
    my $start_date_regex =
qr/(?:$start_julian_without_feb29_regex|$start_julian_with_feb29_regex|$start_month_week_day_regex)/smx;
    my $start_hour_regex   = qr/(?\-?\d+)/smx;
    my $start_minute_regex = qr/(?::(?\d+))/smx;
    my $start_second_regex = qr/(?::(?\d+))/smx;
    my $start_time_regex =
      qr/[\/]$start_hour_regex$start_minute_regex?$start_second_regex?/smx;
    my $start_datetime_regex = qr/$start_date_regex(?:$start_time_regex)?/smx;
    my $end_julian_without_feb29_regex =
      qr/(?:J(?\d{1,3}))/smx;
    my $end_julian_with_feb29_regex = qr/(?\d{1,3})/smx;
    my $end_month_regex             = qr/(?\d{1,2})/smx;
    my $end_week_regex              = qr/(?[1-5])/smx;
    my $end_day_regex               = qr/(?[0-6])/smx;
    my $end_month_week_day_regex =
      qr/(?:M$end_month_regex[.]$end_week_regex[.]$end_day_regex)/smx;
    my $end_date_regex =
qr/(?:$end_julian_without_feb29_regex|$end_julian_with_feb29_regex|$end_month_week_day_regex)/smx;
    my $end_hour_regex   = qr/(?\-?\d+)/smx;
    my $end_minute_regex = qr/(?::(?\d+))/smx;
    my $end_second_regex = qr/(?::(?\d+))/smx;
    my $end_time_regex =
      qr/[\/]$end_hour_regex$end_minute_regex?$end_second_regex?/smx;
    my $end_datetime_regex = qr/$end_date_regex(?:$end_time_regex)?/smx;

    if ( $tz_variable =~
/^$std_name_regex$std_offset_regex(?:$dst_name_regex(?:$dst_offset_regex)?,$start_datetime_regex,$end_datetime_regex)?$/smx
      )
    {
        my $tz_definition = { tz => $tz_variable };
        foreach my $key (
            qw(std_name std_sign std_hours std_minutes std_seconds dst_name dst_sign dst_hours dst_minutes dst_seconds start_julian_without_feb29 end_julian_withou_feb29 start_julian_with_feb29 end_julian_with_feb29 start_month end_month start_week end_week start_day end_day start_hour end_hour start_minute end_minute start_second end_second)
          )
        {
            if ( defined $LAST_PAREN_MATCH{$key} ) {
                $tz_definition->{$key} = $LAST_PAREN_MATCH{$key};
            }
        }
        $self->_initialise_undefined_tz_definition_values($tz_definition);
        $tz_definition->{std_offset_in_seconds} =
          $self->_std_offset_in_seconds($tz_definition);
        $tz_definition->{dst_offset_in_seconds} =
          $self->_dst_offset_in_seconds($tz_definition);
        return $tz_definition;
    }
    else {
        Carp::croak(
            "Failed to parse the tz defintion of $tz_variable from $path");
    }
}

sub _dst_offset_in_seconds {
    my ( $self, $tz_definition ) = @_;
    my $dst_offset_in_seconds = $tz_definition->{dst_seconds} || 0;
    if ( defined $tz_definition->{dst_minutes} ) {
        $dst_offset_in_seconds +=
          $tz_definition->{dst_minutes} * _SECONDS_IN_ONE_MINUTE();
    }
    if ( defined $tz_definition->{dst_hours} ) {
        $dst_offset_in_seconds +=
          $tz_definition->{dst_hours} *
          _MINUTES_IN_ONE_HOUR() *
          _SECONDS_IN_ONE_MINUTE();
    }
    if (   ( defined $tz_definition->{dst_sign} )
        && ( $tz_definition->{dst_sign} eq q[-] ) )
    {
    }
    else {
        $dst_offset_in_seconds *= _NEGATIVE_ONE();
    }
    if ( $dst_offset_in_seconds == 0 ) {
        $dst_offset_in_seconds = $tz_definition->{std_offset_in_seconds} +
          ( _MINUTES_IN_ONE_HOUR() * _SECONDS_IN_ONE_MINUTE() );
    }
    return $dst_offset_in_seconds;
}

sub _std_offset_in_seconds {
    my ( $self, $tz_definition ) = @_;
    my $std_offset_in_seconds = $tz_definition->{std_seconds} || 0;

    if ( defined $tz_definition->{std_minutes} ) {
        $std_offset_in_seconds +=
          $tz_definition->{std_minutes} * _SECONDS_IN_ONE_MINUTE();
    }
    if ( defined $tz_definition->{std_hours} ) {
        $std_offset_in_seconds +=
          $tz_definition->{std_hours} *
          _MINUTES_IN_ONE_HOUR() *
          _SECONDS_IN_ONE_MINUTE();
    }
    if (   ( defined $tz_definition->{std_sign} )
        && ( $tz_definition->{std_sign} eq q[-] ) )
    {
    }
    else {
        $std_offset_in_seconds *= _NEGATIVE_ONE();
    }
    return $std_offset_in_seconds;
}

sub _initialise_undefined_tz_definition_values {
    my ( $self, $tz_definition ) = @_;
    $tz_definition->{start_hour} =
      defined $tz_definition->{start_hour}
      ? $tz_definition->{start_hour}
      : _DEFAULT_DST_START_HOUR();
    $tz_definition->{start_minute} =
      defined $tz_definition->{start_minute}
      ? $tz_definition->{start_minute}
      : 0;
    $tz_definition->{start_second} =
      defined $tz_definition->{start_second}
      ? $tz_definition->{start_second}
      : 0;
    $tz_definition->{end_hour} =
      defined $tz_definition->{end_hour}
      ? $tz_definition->{end_hour}
      : _DEFAULT_DST_END_HOUR();
    $tz_definition->{end_minute} =
      defined $tz_definition->{end_minute}
      ? $tz_definition->{end_minute}
      : 0;
    $tz_definition->{end_second} =
      defined $tz_definition->{end_second}
      ? $tz_definition->{end_second}
      : 0;
    return;
}

sub _set_abbrs {
    my ( $self, $tz ) = @_;
    my $index = 0;
    foreach
      my $local_time_type ( @{ $self->{_tzdata}->{$tz}->{local_time_types} } )
    {
        if ( $self->{_tzdata}->{$tz}->{local_time_types}->[ $index + 1 ] ) {
            $local_time_type->{abbr} =
              substr $self->{_tzdata}->{$tz}->{time_zone_abbreviation_strings},
              $local_time_type->{abbrind},
              $self->{_tzdata}->{$tz}->{local_time_types}->[ $index + 1 ]
              ->{abbrind};
        }
        else {
            $local_time_type->{abbr} =
              substr $self->{_tzdata}->{$tz}->{time_zone_abbreviation_strings},
              $local_time_type->{abbrind};
        }
        $local_time_type->{abbr} =~ s/\0+$//smx;
        $index += 1;
    }
    return;
}

sub _read_v1_tzfile {
    my ( $self, $handle, $path, $header, $tz ) = @_;
    $self->{_tzdata}->{$tz}->{transition_times} =
      $self->_read_transition_times( $handle, $path, $header->{timecnt},
        _SIZE_OF_TRANSITION_TIME_V1() );
    $self->{_tzdata}->{$tz}->{local_time_indexes} =
      $self->_read_local_time_indexes( $handle, $path, $header->{timecnt} );
    $self->{_tzdata}->{$tz}->{local_time_types} =
      $self->_read_local_time_types( $handle, $path, $header->{typecnt} );
    $self->{_tzdata}->{$tz}->{time_zone_abbreviation_strings} =
      $self->_read_time_zone_abbreviation_strings( $handle, $path,
        $header->{charcnt} );
    $self->_set_abbrs($tz);
    $self->{_tzdata}->{$tz}->{leap_seconds} =
      $self->_read_leap_seconds( $handle, $path, $header->{leapcnt},
        _SIZE_OF_LEAP_SECOND_V1() );
    $self->{_tzdata}->{$tz}->{is_std} =
      $self->_read_is_standard_time( $handle, $path, $header->{ttisstdcnt} );
    $self->{_tzdata}->{$tz}->{is_gmt} =
      $self->_read_is_gmt( $handle, $path, $header->{ttisstdcnt} );
    return;
}

sub _read_v2_tzfile {
    my ( $self, $handle, $path, $header, $tz ) = @_;

    if (   ( $header->{version} )
        && ( $header->{version} >= 2 )
        && ( defined $Config{'d_quad'} )
        && ( $Config{'d_quad'} eq 'define' ) )
    {
        $self->{_tzdata}->{$tz} = {};
        $header = $self->_read_header( $handle, $path );
        $self->{_tzdata}->{$tz}->{transition_times} =
          $self->_read_transition_times( $handle, $path, $header->{timecnt},
            _SIZE_OF_TRANSITION_TIME_V2() );
        $self->{_tzdata}->{$tz}->{local_time_indexes} =
          $self->_read_local_time_indexes( $handle, $path, $header->{timecnt} );
        $self->{_tzdata}->{$tz}->{local_time_types} =
          $self->_read_local_time_types( $handle, $path, $header->{typecnt} );
        $self->{_tzdata}->{$tz}->{time_zone_abbreviation_strings} =
          $self->_read_time_zone_abbreviation_strings( $handle, $path,
            $header->{charcnt} );
        $self->_set_abbrs($tz);
        $self->{_tzdata}->{$tz}->{leap_seconds} =
          $self->_read_leap_seconds( $handle, $path, $header->{leapcnt},
            _SIZE_OF_LEAP_SECOND_V2() );
        $self->{_tzdata}->{$tz}->{is_std} =
          $self->_read_is_standard_time( $handle, $path,
            $header->{ttisstdcnt} );
        $self->{_tzdata}->{$tz}->{is_gmt} =
          $self->_read_is_gmt( $handle, $path, $header->{ttisstdcnt} );
        $self->{_tzdata}->{$tz}->{tz_definition} =
          $self->_read_tz_definition( $handle, $path );
    }
    return;
}

sub _read_tzfile {
    my ($self) = @_;
    my $tz = $self->timezone();
    my $path = File::Spec->catfile( $self->directory, $tz );
    my $handle = FileHandle->new($path)
      or Carp::croak("Failed to open $path for reading:$EXTENDED_OS_ERROR");
    my @stat = stat $handle
      or Carp::croak("Failed to stat $path:$EXTENDED_OS_ERROR");
    my $last_modified = $stat[ _STAT_MTIME_IDX() ];
    if (   ( $self->{_tzdata}->{$tz}->{last_modified} )
        && ( $self->{_tzdata}->{$tz}->{last_modified} == $last_modified ) )
    {
    }
    elsif (( $_tzdata_cache->{$tz} )
        && ( $_tzdata_cache->{$tz}->{last_modified} )
        && ( $_tzdata_cache->{$tz}->{last_modified} == $last_modified ) )
    {
        $self->{_tzdata}->{$tz} = $_tzdata_cache->{$tz};
    }
    else {
        binmode $handle;
        my $header = $self->_read_header( $handle, $path );
        $self->_read_v1_tzfile( $handle, $path, $header, $tz );
        $self->_read_v2_tzfile( $handle, $path, $header, $tz );
        $self->{_tzdata}->{$tz}->{last_modified} = $last_modified;
        $_tzdata_cache->{$tz} = $self->{_tzdata}->{$tz};
    }
    close $handle
      or Carp::croak("Failed to close $path:$EXTENDED_OS_ERROR");
    return;
}

sub reset_cache {
    my ($self) = @_;
    if ( ref $self ) {
        foreach my $key (qw(_tzdata _zonetab_last_modified _comments _zones)) {
            $self->{$key} = {};
        }
    }
    else {
        $_tzdata_cache  = {};
        $_zonetab_cache = {};
    }
    return;
}

1;
__END__