PHP Calculate Monthly Intervals

monthly_intervals.php

<?php

$start_at = '2012-11-15';
$end_at = strtotime('2012-11-15');
$final_date = strtotime('2013-01-22');
$dates = array();
						
# Calculate intervals.
while($end_at < $final_date){
						
	if(strtotime('2012-11-15') != $end_at)
		$start_at = date("Y-m-d", strtotime("+1 day", $end_at));
	
	$end_of_month = date("Y-m-t", strtotime($start_at));
						
	if(strtotime($end_of_month) > strtotime('2013-01-22'))
		$end_of_month = '2013-01-22';
						
	$dates[] = array(
		"start"=>$start_at,
		"end"=>$end_of_month,
	);
						
	$end_at = strtotime($end_of_month);
						
}
?>

<pre>
<?=print_r($dates)?>
</pre>