Reversing PHP’s mktime

mktime takes a set of six integers and creates a UNIX timestamp. Surely there is a better way of reversing it than this?

$timestring = date("Y-m-d H:i:s", $time);
preg_match('/(\d+)\-(\d+)-(\d+) (\d+):(\d+):(\d+)/', $timestring, $matches);
$year = $matches[1];
$month = $matches[2];
$day = $matches[3];
$hour = $matches[4];
$minute = $matches[5];
$second = $matches[6];