Wordpress - Accurate Trim text function

function pcsite_trim ($text, $maxwords, $allowtags = "") {
// <?php echo pcsite_trim(get_the_content(), 15, "");
  // Strip tags
  $text = strip_tags($text, $allowtags);
 
  //workingonthis-$thinchars = ereg_replace("[^fijlt]", "", $text); 
  //workingonthis-$fatchars = ereg_replace("[^mw]", "", $text);
  //workingonthis-$modifier = 5.1 + ( (strlen($thinchars) / strlen($text)) - (strlen($fatchars) / strlen($text)) );
  $modifier = 5.1; // average letters per word (in normal english it's 4.5, but in blogging and so it increases)
 
  $text = substr($text, 0, $maxwords * $modifier);
 
  $words = explode(" ", $text);
  $words = array_slice($words, 0, count($words) - 1 );
 
  // Array to text
  $text = implode(" ", $words);
  $text = "<p>".$text."...</p>";
 
  return $text;
}