protected function indexAfter($string, $offset = null)
    {
        if ($offset === null) {
            $offset = $this->offset;
        }
        if ($offset + mb_strlen($string, 'UTF-8') > $this->length) {
            return $this->length;
        }

        $afterIndexOf = mb_strpos($this->sql, $string, $offset, 'UTF-8');
        if ($afterIndexOf === false) {
            $afterIndexOf = $this->length;
        } else {
            $afterIndexOf += mb_strlen($string, 'UTF-8');
        }

        return $afterIndexOf;
    }