get month working days between range (exclude weekends &| Greek holidays)

//date range between current year
$d_start= date("Y-01-01");
$d_end= date("Y-12-31");

$row_set=get($db, "select date_start, date_end from user_vacations where user_id=".$_SESSION['id']." and date_end between '{$d_start}' and '{$d_end}'",null);
$count_working_days = 0;

foreach($row_set as $row) {
	$count_working_days.=get_month_working_days_between_range($row["date_start"],$row["date_end"]);
}

echo $count_working_days;

function get_month_working_days_between_range($date_one, $date_two)
{
	$start = strtotime($date_one);
	$end = strtotime($date_two);

	$no_days=0;

	while ($start <= $end) {
		$what_day = date("N", $start);

	    if($what_day < 6) // 6 and 7 are weekend days
	        $no_days++;

	    $start += 86400; // +1 day
	}

	return $no_days;
}

<?php
	$d_start= date("Y-01-01");
	$d_end= date("Y-12-31");
	$row_set=getSet($db, "select date_start, date_end from user_vacations where user_id=".$_SESSION['id']." and date_end between '{$d_start}' and '{$d_end}'",null);
	$count_working_days = 0;

	foreach($row_set as $row) {
		$count_working_days.=$x->get_month_working_days_between_range($row["date_start"],$row["date_end"]);
	}

	echo $count_working_days. " days";
?>

class SimpleWorkingDays
{
	private function orthodox_eastern($year) { 
	    $a = $year % 4; 
	    $b = $year % 7; 
	    $c = $year % 19; 
	    $d = (19 * $c + 15) % 30; 
	    $e = (2 * $a + 4 * $b - $d + 34) % 7; 
	    $month = floor(($d + $e + 114) / 31); 
	    $day = (($d + $e + 114) % 31) + 1; 

	    $de = mktime(0, 0, 0, $month, $day + 13, $year); 

	    return date('Y-m-d',$de); 
	} 

	private function get_vacation_days($year)
	{
		$vacations = array();
		$easter = $this->orthodox_eastern($year);
		$vacations[] = "01.01"; //prwtoxronia
		$vacations[] = "06.01"; //8eofaneia
		$vacations[] = "25.03"; //25martioy
		$vacations[] = "01.05"; //1maioy - ergatikh protomagia
		$vacations[] = "15.08"; //15aug - koimhsh 8eotokoy
		$vacations[] = "26.10"; //26oct - polioyxoy 8essalonikhs
		$vacations[] = "28.10"; //28oct - epeteios toy oxi
		$vacations[] = "25.12"; //25dec - christmas
		$vacations[] = "26.12"; //26dec - christmas - 2nd day - syna3is tis 8eotokoy
		$vacations[] = date('d.m',strtotime($easter)); //orthodox easter
		$vacations[] = date('d.m',strtotime($easter."-48 days")); //clean monday
		$vacations[] = date('d.m',strtotime($easter."-2 days")); //big friday
		$vacations[] = date('d.m',strtotime($easter."+50 days")); //agioy pneymatos
		$vacations[] = date('d.m',strtotime($easter."+1 days")); //deytera toy pasxa

		return $vacations;
	}

	//get working days
	function get_month_working_days_between_range($date_one, $date_two)
	{
		$vacation_days = $this->get_vacation_days($year);

		$start = strtotime($date_one);
		$end = strtotime($date_two);

		$no_days=0;

		while ($start <= $end) {
			$get_name4vacation = date('d.m', $start);

			//when doesnt exist in vacation days			
			if (!in_array($get_name4vacation, $vacation_days)){
				$what_day = date("N", $start);

			    if($what_day < 6) // 6 and 7 are weekend days
			        $no_days++;
		    }

		    $start += 86400; // +1 day
		}

		return $no_days;
	}

	//get working day in month
	function get_month_working_days($month, $year)
	{
		$day_count = cal_days_in_month(CAL_GREGORIAN, $month, $year); // builtin function - get amount of days
		$vacation_days = $this->get_vacation_days($year);

		$exclude=0;

		for ($i = 1; $i <= $day_count; $i++) {
				$get_name = date('D', strtotime($year.'/'.$month.'/'.$i)); //get day
				$get_name4vacation = date('d.m', strtotime($year.'/'.$month.'/'.$i));

				if($get_name == 'Sun' || $get_name == 'Sat' || in_array($get_name4vacation, $vacation_days)){
					$exclude+=1;
				}
		}

		return ($day_count - $exclude);
	}
}