Truncate a string without spitting on a word, and without any trailing punctuation from the original string. (PHP)

String Truncate

function str_truncate($string, $length) {
    $bogus = array(",", ".", "?", "!", ";", "/", "$", "%", "*", "&", "#", "+", "=");
    if (strlen($string) > $length) {
        $string = substr($string, 0, ($length -3));
        $string = substr($string, 0, strrpos($string, ' '));
        if(in_array(substr($string, -1), $bogus)){
            $string = substr($string, 0, strlen($string)-1);
        }
        $string .= "...";
    }
    return $string;
}