29         'em' => 
true, 
'ex' => 
true, 
'px' => 
true, 
'in' => 
true,
 
   30         'cm' => 
true, 
'mm' => 
true, 
'pt' => 
true, 
'pc' => 
true 
   38         $this->
n = (string) 
$n;
 
   39         $this->unit = $u !== 
false ? (string) $u : 
false;
 
   46     static public function make($s) {
 
   48         $n_length = strspn($s, 
'1234567890.+-');
 
   49         $n = substr($s, 0, $n_length);
 
   50         $unit = substr($s, $n_length);
 
   52         return new HTMLPurifier_Length(
$n, 
$unit);
 
   60         if ($this->
n === 
'+0' || $this->
n === 
'-0') $this->
n = 
'0';
 
   61         if ($this->
n === 
'0' && $this->unit === 
false) 
return true;
 
   62         if (!ctype_lower($this->unit)) $this->unit = strtolower($this->unit);
 
   66         $result = $def->validate($this->
n, 
false, 
false);
 
   67         if (
$result === 
false) 
return false;
 
   76         if (!$this->
isValid()) 
return false;
 
  104         if ($l === 
false) 
return false;
 
  105         if ($l->unit !== $this->unit) {
 
  107             $l = $converter->convert($l, $this->unit);
 
  108             if ($l === 
false) 
return false;
 
  110         return $this->
n - $l->n;