public function decode($based)
    {
        if (!is_array($based)) {
            $based = str_split($based);
        }
        $numbers = [];
        $char2int = $this->char2int;
        foreach ($based as $char) {
            if (isset($char2int[$char])) {
                $numbers[] = $char2int[$char];
            } else {
                throw new InvalidBase64($based);
            }
        }
        return $numbers;
    }