NAME

Date::Span -- deal with date/time ranges than span multiple dates

VERSION

version 1.125

SYNOPSIS

 use Date::Span;

 @spanned = range_expand($start, $end);

 print "from $_->[0] to $_->[1]\n" for (@spanned);

DESCRIPTION

This module provides code for dealing with datetime ranges that span multiple calendar days. This is useful for computing, for example, the amount of seconds spent performing a task on each day. Given the following table:

  event   | begun            | ended
 ---------+------------------+------------------
  loading | 2004-01-01 00:00 | 2004-01-01 12:45
  venting | 2004-01-01 12:45 | 2004-01-02 21:15
  running | 2004-01-02 21:15 | 2004-01-03 00:00

We may want to gather the following data:

  date       | event   | time spent
 ------------+---------+----------------
  2004-01-01 | loading | 12.75 hours
  2004-01-01 | venting | 11.25 hours
  2004-01-02 | venting | 21.25 hours
  2004-01-02 | running |  2.75 hours

Date::Span takes a data like the first and produces data more like the second. (Details on exact interface are below.)

FUNCTIONS

range_durations($start, $end)

Given $start and $end as timestamps (in epoch seconds), range_durations returns a list of arrayrefs. Each arrayref is a date (expressed as epoch seconds at midnight) and the number of seconds for which the given range intersects with the date.

range_expand($start, $end)

Given $start and $end as timestamps (in epoch seconds), range_durations returns a list of arrayrefs. Each arrayref is a start and end timestamp. No pair of start and end times will cross a date boundary, and the set of ranges as a whole will be identical to the passed start and end.

range_from_unit(@date_unit)

@date_unit is a specification of a unit of time, in the form:

 @date_unit = ($year, $month, $day, $hour, $minute);

Only $year is mandatory; other arguments may be added, in order. Month is given in the range (0 .. 11). This function will return the first and last second of the given unit.

A code reference may be passed as the last object. It will be used to convert the date specification to a starting time. If no coderef is passed, a simple one using Time::Local (and timegm) will be used.

TODO

This code was just yanked out of a general purpose set of utility functions I've compiled over the years. It should be refactored (internally) and further tested. The interface should stay pretty stable, though.

AUTHOR

Ricardo SIGNES, <rjbs@cpan.org>

COPYRIGHT

(C) 2004-2006, Ricardo SIGNES. Date::Span is available under the same terms as Perl itself.