Write a PHP function to sort an array according to another array acting as a priority list

<?php
function list_cmp($a, $b) 
{ 
  global $order; 

  foreach($order as $key => $value) 
    { 
      if($a==$value) 
        { 
          return 0; 
          break; 
        } 

      if($b==$value) 
        { 
          return 1; 
          break; 
        } 
    } 
} 

$order[0] = 1;
$order[1] = 3; 
$order[2] = 4; 
$order[3] = 2; 

$array[0] = 2;
$array[1] = 1; 
$array[2] = 3; 
$array[3] = 4; 
$array[4] = 2; 
$array[5] = 1; 
$array[6] = 2; 

usort($array, "list_cmp"); 

print_r($array); 
?>

Sample Output:

Array                                                       
(                                                           
    [0] => 1                                                
    [1] => 1                                                
    [2] => 3                                                
    [3] => 4                                                
    [4] => 2                                                
    [5] => 2                                                
    [6] => 2                                                
)