lib/htmlpurifier/HTMLPurifier/AttrDef/Lang.php

   1 <?php
   2
   3 require_once 'HTMLPurifier/AttrDef.php';
   4
   5 /**
   6  * Validates the HTML attribute lang, effectively a language code.
   7  * @note Built according to RFC 3066, which obsoleted RFC 1766
   8  */
   9 class HTMLPurifier_AttrDef_Lang extends HTMLPurifier_AttrDef
  10 {
  11
  12     function validate($string, $config, &$context) {
  13
  14         $string = trim($string);
  15         if (!$string) return false;
  16
  17         $subtags = explode('-', $string);
  18         $num_subtags = count($subtags);
  19
  20         if ($num_subtags == 0) return false; // sanity check
  21
  22         // process primary subtag : $subtags[0]
  23         $length = strlen($subtags[0]);
  24         switch ($length) {
  25             case 0:
  26                 return false;
  27             case 1:
  28                 if (! ($subtags[0] == 'x' || $subtags[0] == 'i') ) {
  29                     return false;
  30                 }
  31                 break;
  32             case 2:
  33             case 3:
  34                 if (! ctype_alpha($subtags[0]) ) {
  35                     return false;
  36                 } elseif (! ctype_lower($subtags[0]) ) {
  37                     $subtags[0] = strtolower($subtags[0]);
  38                 }
  39                 break;
  40             default:
  41                 return false;
  42         }
  43
  44         $new_string = $subtags[0];
  45         if ($num_subtags == 1) return $new_string;
  46
  47         // process second subtag : $subtags[1]
  48         $length = strlen($subtags[1]);
  49         if ($length == 0 || ($length == 1 && $subtags[1] != 'x') || $length > 8 || !ctype_alnum($subtags[1])) {
  50             return $new_string;
  51         }
  52         if (!ctype_lower($subtags[1])) $subtags[1] = strtolower($subtags[1]);
  53
  54         $new_string .= '-' . $subtags[1];
  55         if ($num_subtags == 2) return $new_string;
  56
  57         // process all other subtags, index 2 and up
  58         for ($i = 2; $i < $num_subtags; $i++) {
  59             $length = strlen($subtags[$i]);
  60             if ($length == 0 || $length > 8 || !ctype_alnum($subtags[$i])) {
  61                 return $new_string;
  62             }
  63             if (!ctype_lower($subtags[$i])) {
  64                 $subtags[$i] = strtolower($subtags[$i]);
  65             }
  66             $new_string .= '-' . $subtags[$i];
  67         }
  68
  69         return $new_string;
  70
  71     }
  72
  73 }
  74
  75 ?>