Intervalle entre 2 dates sans les week end

<?php 
  
 $date_debut = '01/01/2012'; 
 $date_fin = '28/02/2012'; 
 list($dd,$md,$yd) = explode('/',$date_debut); 
 list($df,$mf,$yf) = explode('/',$date_fin); 
  
 $timstamp_debut = mktime(0,0,0,$md,$dd,$yd); 
 $timstamp_fin = mktime(0,0,0,$mf,$df,$yf); 
  
 $conges = 0; 
 $jours = 0; 
 // 86400 -> nombre de seconde par jour 
 for($i = $timstamp_debut; $i <= $timstamp_fin; $i+= 86400){ 
  if(in_array(date('w', $i) , array(1,2,3,4,5))){ 
   $conges++; 
  } 
  $jours++; 
 } 
 echo $conges.' sur '.$jours; 

?>