void getBytes(uint8_t* buf, uint32_t  len)
    {
        if (0 == memcpy_s(buf, len, p_buffer_ + position_, remaining()))
            position_ = position_ + len;
    }
    void getBytes(uint32_t index, uint8_t* buf, uint32_t len) const
    {
        memcpy_s(buf, len, p_buffer_ + index, limit_ - index);
    }