PHP: getting weekdays numbers of a given month - php

Question

Given a Month and a weekday, I need to build a function that can retrieve the day number of all Mondays, Tuesdays, Wednesdays, Thursdays and Fridays.
Let's say I give the function this month, September 2012 and weekday number 1. The function should retrieve all the Mondays in September 2012 which are: 3, 10, 17 and 24
Please note that to me weekday number 1 is Monday, number 2 Tuesday, 3 is Wednesday, 4 Thursday and 5 Friday.
So far I've have done: getting the first day of the week given today's date (I post the function below). But I don't know how to follow from here in a simple way, I've been many hours on it and I suspect there's a better way to do it. Can you please show me how?
function getFirstDayOfWeek($date) {
$getdate = getdate($date);
// How many days ahead monday are we?
switch ( $getdate['wday'] ) {
case 0: // we are on sunday
$days = 6;
break;
default: // any other day
$days = $getdate['wday']-1;
break;
}
$seconds = $days*24*60*60;
$monday = date($getdate[0])-$seconds;
return $monday;
}
Thanks a ton

Answer 1

Not very smart, but would works for you:
// sept. 2012
$month = 9;
// loop through month days
for ($i = 1; $i <= 31; $i++) {
// given month timestamp
$timestamp = mktime(0, 0, 0, $month, $i, 2012);
// to be sure we have not gone to the next month
if (date("n", $timestamp) == $month) {
// current day in the loop
$day = date("N", $timestamp);
// if this is between 1 to 5, weekdays, 1 = Monday, 5 = Friday
if ($day == 1 OR $day <= 5) {
// write it down now
$days[$day][] = date("j", $timestamp);
}
}
}
// to see if it works :)
print_r($days);