private function encodeValue($val, $base)
    {
        $this->preOpMethodParamsCheck(array($val, $base));

        $digits = $this->baseCheck($base);

        try {

            $new = '';

            while ($this->math->comp($val, '0') > 0) {
                $qq  = $this->math->div($val, $base);
                $rem = $this->math->mod($val, $base);
                $val = $qq;
                $new = $new . $digits[$rem];
            }

            return $new;

        } catch (\Exception $e) {
            throw $e;
        }
    }