---
name: "Lire::WeekCalculator"
section: "3pm"
platform: "linux"
package: "lire"
version: "2.1.1-8"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/Lire::WeekCalculator"
---

# Lire::WeekCalculator(3pm)

handle different weeknumbering schemes

## NAME

Lire::WeekCalculator - handle different weeknumbering schemes

## SYNOPSIS

```
    use Lire::WeekCalculator;
    my $week_calc = new Lire::WeekCalculator();
    my $week_no   = $week_calc->week_number( $time );
```

## DESCRIPTION

We support three values for LR\_WEEK\_NUMBERING: ISO (strftime's `%V`): week starts on monday; W (week starts on monday) and U (week starts on sunday). See **strftime**(1).

## CONSTRUCTOR

### new( %params )

Creates a new week calculator. The style of week numbering is selected using the `"style"` parameter. If that parameter is omitted, it defaults to the style set in 'lr\_week\_numbering' configuration variable.

### style()

Returns the week numbering style used. This will be either `"U"`, `"W"` or `"ISO"`.

### week\_number( $time )

Returns the week number of `$time` according the current week numbering scheme. The week number returned is between 1 and 53.

### week\_idx( $time )

Returns the week index of `$time` according to the week numbering scheme. The week index is Lire specific and is used to normalise computations between different scheme in regards of the first incomplete week of the year. In the ISO case, the week index is always equals to **week\_number()** - 1, for the other style, the week index of the week 0 will be one less than the last week number of the previous year.

### last\_week\_of\_year($year)

Returns the week number of the last week in the year `$year`.

### week\_start( $year, $week\_no )

Returns the epoch time of the first day of week `$week_no` in year `$year` when calculated using current style.

### find\_year\_week1\_start\_date($year)

Returns the date (epoch) at which the first day of the first week of the year `$year` starts.

### strformat()

Returns a string that can be used as the format specificier in calls to strftime to print the week number of this style.

### strfdate()

Emulates **POSIX::strftime()** but picks up the `%V` if the system strftime doesn't support it. Should be called whenever you use format strings that may contain week-of-the-year-codes.

## AUTHORS

```
  Joost van Baal <joostvb@logreport.org>,
  Francis J. Lacoste <flacoste@logreport.org>,
  Wessel Dankers <wsl@logreport.org>
```

## VERSION

`$Id:` WeekCalculator.pm,v 1.16 2006/07/23 13:16:30 vanbaal Exp $

## COPYRIGHT

Copyright (C) 2002 Stichting LogReport Foundation LogReport@LogReport.org

This file is part of Lire.

Lire is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program (see COPYING); if not, check with http://www.gnu.org/copyleft/gpl.html.