PHP TZ setting length

Question

I was wonder what is the maximum length of the timezone settings in PHP? I'm storing the string in a database, and would like to keep the length as short as possible, but i see timezones like "Canada/East-Saskatchewan", which goes beyond our current limit.

If I could just get a list of all the supported timezone string, I can sort them, but they are currently split on to several different pages.

linky: http://www.php.net/manual/en/timezones.php

Answer 1

Every timezone can be abbreviated into 4 characters or less. (http://www.timeanddate.com/library/abbreviations/timezones/) So then maybe you can simple build a static array of the full name timezones linking them to their abbreviated name. This will allow you to use both.

$timeZone = 'Canada/East-Saskatchewan';
$tz = DateTimeZone::listAbbreviations();
echo recursiveArraySearch($tz, $timeZone);
function recursiveArraySearch($haystack, $needle, $index = null) {
    $aIt     = new RecursiveArrayIterator($haystack);
    $it    = new RecursiveIteratorIterator($aIt);
    while($it->valid()) {       
        if (((isset($index) AND ($it->key() == $index)) OR (!isset($index))) AND ($it->current() == $needle)) {
            return $aIt->key();
        }
        $it->next();
    }
    return false;
}

Answer 2

From the manual:

<?php
$timezone_identifiers = DateTimeZone::listIdentifiers();
for ($i=0; $i < 5; $i++) {
    echo "$timezone_identifiers[$i]\n";
}
?>

Answer 3

Answer is 32. And here is the complete PHP code to find that:

<?php
$timezone_identifiers = DateTimeZone::listIdentifiers();

$maxlen = 0;
foreach($timezone_identifiers as $id)
{
    if(strlen($id) > $maxlen)
        $maxlen = strlen($id);
}

echo "Max Length: $maxlen";

/*
Output:

Max Length: 32

*/
?>

Answer 4

The Olson database - available from ftp://elsie.nci.nih.gov/pub/ (but see also http://www.twinsun.com/tz/tz-link.htm and http://en.wikipedia.org/wiki/Tz_database) - is the source of these names. The documentation in the file Theory includes a description of how the zone names are formed. This would help you establish how long names can be.

The longest 'current' names are 30 characters (America/Argentina/Buenos_Aires, America/Argentina/Rio_Gallegos, America/North_Dakota/New_Salem); the longest 'backwards compatibility' name is 32 characters (America/Argentina/ComodRivadavia).