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Time-Tzfile-0.01
River stage zero No dependents
/ Time::Tzfile

NAME

Time::Tzfile - reads a binary tzfile into a hashref

VERSION

version 0.01

SYNOPSIS

  use Time::Tzfile;

  # will get 64bit timestamps if available
  my $tzdata = Time::Tzfile->parse({filename => '/usr/share/zoneinfo/Europe/London'});

  # will always get 32bit timestamps
  my $tzdata = Time::Tzfile->parse({
    filename        => '/usr/share/zoneinfo/Europe/London',
    use_version_one => 1,
  });

METHODS

parse ({filename => /path/to/tzfile, use_version_one => 1})

The parse takes a hashref containing the filename of the tzfile to open and optionally a flag to use the version one (32bit) tzfile entry. Returns a hashref containing the tzfile data.

Tzfiles can have two entries in them: the version one entry with 32bit timestamps and the version two entry with 64bit timestamps. If the tzfile has the version two entry, and if perl is compiled with 64bit support, this method will automatically return the version two entry. If you want to force the version one entry, include the use_version_one flag in the method arguments.

The hashref returned looks like this:

  {
    header         => {}, # version and counts for the body
    transitions    => [], # historical timestamps when TZ changes occur
    transition_idx => [], # index of ttinfo structs which apply to transitions
    ttinfo_structs => [], # hashrefs of gmt offset, dst flag & the tz abbrev idx
    tz_abbreviation=> $,  # scalar of tz abbreviations (GMT, BST etc)
    leap_seconds   => [], # hashrefs of the timestamp & offset to apply leap secs
    std_wall       => [], # arrayref of std wall clock indicators
    gmt_local      => [], # arrayref of gm local indicators
  }

I believe that all binary tzfiles are compiled with UTC timestamps, in which case you can ignore std_wall and gmt_local entries for calculating offsets.

See #SYNOPSIS for examples.

SEE ALSO

TZFILE FORMAT INFO

I found these resources useful guides to understanding the tzfile format

  • Tzfile manpage

  • Very useful description of tzfile format from Bloomberg

  • Wikipedia entry on the TZ database

AUTHOR

David Farrell <dfarrell@cpan.org>

COPYRIGHT AND LICENSE

This software is Copyright (c) 2016 by David Farrell.

This is free software, licensed under:

  The (two-clause) FreeBSD License