CI_Utf8::clean_string PHP Method

    public function clean_string($str)
    {
        if ($this->is_ascii($str) === FALSE) {
            if (MB_ENABLED) {
                $str = mb_convert_encoding($str, 'UTF-8', 'UTF-8');
            } elseif (ICONV_ENABLED) {
                $str = @iconv('UTF-8', 'UTF-8//IGNORE', $str);
            }
        }
        return $str;
    }