php restore tags

<?PHP
  // Found on http://www.the-art-of-web.com/php/truncate/

  // Original PHP code by Chirp Internet: www.chirp.com.au
  // Please acknowledge use of this code by including this header.

  function restoreTags($input)
  {
    $opened = array();

    // loop through opened and closed tags in order
    if(preg_match_all("/<(\/?[a-z]+)>?/i", $input, $matches)) {
      foreach($matches[1] as $tag) {
        if(preg_match("/^[a-z]+$/i", $tag, $regs)) {
          // a tag has been opened
          if(strtolower($regs[0]) != 'br') $opened[] = $regs[0];
        } elseif(preg_match("/^\/([a-z]+)$/i", $tag, $regs)) {
          // a tag has been closed
          unset($opened[array_pop(array_keys($opened, $regs[1]))]);
        }
      }
    }

    // close tags that are still open
    if($opened) {
      $tagstoclose = array_reverse($opened);
      foreach($tagstoclose as $tag) $input .= "</$tag>";
    }

    return $input;
  }
?>