File indexing completed on 2025-01-26 05:29:06

 <?php
 
 /**
  * Validates the HTML attribute lang, effectively a language code.
  * @note Built according to RFC 3066, which obsoleted RFC 1766
  */
 class HTMLPurifier_AttrDef_Lang extends HTMLPurifier_AttrDef
 {
 
     /**
      * @param string $string
      * @param HTMLPurifier_Config $config
      * @param HTMLPurifier_Context $context
      * @return bool|string
      */
     public function validate($string, $config, $context)
     {
         $string = trim($string);
         if (!$string) {
             return false;
         }
 
         $subtags = explode('-', $string);
         $num_subtags = count($subtags);
 
         if ($num_subtags == 0) { // sanity check
             return false;
         }
 
         // process primary subtag : $subtags[0]
         $length = strlen($subtags[0]);
         switch ($length) {
             case 0:
                 return false;
             case 1:
                 if (!($subtags[0] == 'x' || $subtags[0] == 'i')) {
                     return false;
                 }
                 break;
             case 2:
             case 3:
                 if (!ctype_alpha($subtags[0])) {
                     return false;
                 } elseif (!ctype_lower($subtags[0])) {
                     $subtags[0] = strtolower($subtags[0]);
                 }
                 break;
             default:
                 return false;
         }
 
         $new_string = $subtags[0];
         if ($num_subtags == 1) {
             return $new_string;
         }
 
         // process second subtag : $subtags[1]
         $length = strlen($subtags[1]);
         if ($length == 0 || ($length == 1 && $subtags[1] != 'x') || $length > 8 || !ctype_alnum($subtags[1])) {
             return $new_string;
         }
         if (!ctype_lower($subtags[1])) {
             $subtags[1] = strtolower($subtags[1]);
         }
 
         $new_string .= '-' . $subtags[1];
         if ($num_subtags == 2) {
             return $new_string;
         }
 
         // process all other subtags, index 2 and up
         for ($i = 2; $i < $num_subtags; $i++) {
             $length = strlen($subtags[$i]);
             if ($length == 0 || $length > 8 || !ctype_alnum($subtags[$i])) {
                 return $new_string;
             }
             if (!ctype_lower($subtags[$i])) {
                 $subtags[$i] = strtolower($subtags[$i]);
             }
             $new_string .= '-' . $subtags[$i];
         }
         return $new_string;
     }
 }
 
 // vim: et sw=4 sts=4