gistfile1.php

for($orderlines as $ol_id=>$ol_amount) {
  if ($ol_amount <= $available) {
    identify_and_add_refund_detail($refund_id, $ol_amount, $ol_id);
    unset($orderlines[$ol_id]);
  } else {
    identify_and_add_refund_detail($refund_id, $available, $ol_id);
    $leftover = $ol_amount - $available;
    $orderlines[$ol_id] = $leftover;
  }
  $available -= $ol_amount;
  if ($available <= 0) {
    break;
  }
}