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   1  <?php
   2  
   3  /**
   4   * Validates contents based on NMTOKENS attribute type.
   5   * @note The only current use for this is the class attribute in HTML
   6   * @note Could have some functionality factored out into Nmtoken class
   7   * @warning We cannot assume this class will be used only for 'class'
   8   *          attributes. Not sure how to hook in magic behavior, then.
   9   */
  10  class HTMLPurifier_AttrDef_HTML_Nmtokens extends HTMLPurifier_AttrDef
  11  {
  12  
  13      public function validate($string, $config, $context) {
  14  
  15          $string = trim($string);
  16  
  17          // early abort: '' and '0' (strings that convert to false) are invalid
  18          if (!$string) return false;
  19  
  20          // OPTIMIZABLE!
  21          // do the preg_match, capture all subpatterns for reformulation
  22  
  23          // we don't support U+00A1 and up codepoints or
  24          // escaping because I don't know how to do that with regexps
  25          // and plus it would complicate optimization efforts (you never
  26          // see that anyway).
  27          $matches = array();
  28          $pattern = '/(?:(?<=\s)|\A)'. // look behind for space or string start
  29                     '((?:--|-?[A-Za-z_])[A-Za-z_\-0-9]*)'.
  30                     '(?:(?=\s)|\z)/'; // look ahead for space or string end
  31          preg_match_all($pattern, $string, $matches);
  32  
  33          if (empty($matches[1])) return false;
  34  
  35          // reconstruct string
  36          $new_string = '';
  37          foreach ($matches[1] as $token) {
  38              $new_string .= $token . ' ';
  39          }
  40          $new_string = rtrim($new_string);
  41  
  42          return $new_string;
  43  
  44      }
  45  
  46  }
  47  
  48  // vim: et sw=4 sts=4