问有没有办法实现一个像cin的无限输入流？

//template <typename T>
using T = bool;
using _Elem = char;
using _Traits = std::char_traits<_Elem>;
using  _Alloc = std::allocator<_Elem>;
class PromiseAFuture {
public:
    std::promise<T> Pro;
    std::future<T> ip;
    std::mutex lock;
    std::atomic_bool canset = false;
    PromiseAFuture() {
        Pro = std::promise<T>();
        ip = Pro.get_future();
        canset = true;
    }
    bool set(T it) {
        if (canset)
        {
            Pro.set_value(it);
            canset = false;
            return true;
        }
        return false;
    }
    template <class _Rep, class _Period>
    std::future_status wait_for(T& getc, const std::chrono::duration<_Rep, _Period>& _Rel_time) {
        auto icp = ip.wait_for(_Rel_time);
        if (icp == std::future_status::ready)
        {
            getc = ip.get();
            Pro = std::promise<T>();
            ip = Pro.get_future();
            canset = true;
        }
        return icp;
    }
};
//template<class _Elem, class _Traits = std::char_traits<_Elem>, class _Alloc = std::allocator<_Elem>>
class Syncstreambuf : public std::basic_streambuf<_Elem, _Traits> {
public:
    using char_type = _Elem;
    using traits_type = _Traits;
    using int_type = typename _Traits::int_type;
    using off_type = typename _Traits::off_type;
    using Buftype = std::basic_streambuf<_Elem, _Traits>;
    using StringTpye = std::vector<_Elem, _Alloc>;
private:
    StringTpye buffer;//输出区与输入区公用
    std::mutex lock;
    PromiseAFuture needallread;//需要输入区全部被读
    PromiseAFuture needallwriter;//需要输出区被写入
public:
    ~Syncstreambuf()override {
    }
protected:
    //输入区已经读到结尾
    int_type underflow()override {
        std::unique_lock<std::mutex> lk(lock);
       
        if (gptr() == epptr()) {
            //输入区已经读到输出区结尾 需要输出区更新（需要输出区被写入）
            auto statc = std::future_status::timeout; bool var = false;
            while (statc == std::future_status::timeout) {
                lk.unlock();
                //等待 输出区被重新写入
                statc = needallwriter.wait_for(var,1ms);
                lk.lock();
            }
            //输入区指针重新设置  当前已经读到结尾 输入区当前指针设置为buf开始  结束指针为输出区当前指针
            setg(&buffer.front(), &buffer.front(), pptr());
            
        }
        else {

            while ((pptr() - gptr()) <= 0) {
                //等待输出区pptr移动 （输出区更新）
                lk.unlock();
                std::this_thread::sleep_for(1ms);
                lk.lock();
            }
            //输入区指针重新设置
            setg(&buffer.front(), gptr(), pptr());
        }
        // 输入区已全部被读
        needallread.set(true);
        return *gptr();
    }
    std::streamsize xsputn(const char_type* s, std::streamsize count)override {
        std::unique_lock<std::mutex> lk(lock);
        const char_type* __s = s;
        std::streamsize __i = 0;
        std::streamsize __n = count;
        while (__i < __n)
        {
            if (pptr() >= epptr())
            {
                //输出区满，等待输入区
                auto statc = std::future_status::timeout; bool vaar = false; 
                while (statc == std::future_status::timeout) {
                    lk.unlock();
                    //等待 输入区全部被读
                    statc = needallread.wait_for(vaar,1ms);
                    lk.lock();
                }
                //输出区 设置为buf开始 重新写入
                setp(&buffer.front(), &buffer.back());
                
            }
            else
            {


                std::streamsize __chunk_size = std::min(epptr() - pptr(), __n - __i);
                traits_type::copy(pptr(), __s, __chunk_size);
                pbump(__chunk_size);
                __s += __chunk_size;
                __i += __chunk_size;


                //输出区指针已更新
                needallwriter.set(true);
            }
        }
        return __i;
    }
    int_type overflow(int_type ch)override {
        std::unique_lock<std::mutex> lk(lock);
        auto statc = std::future_status::timeout; bool var = false;
        //输出区满，等待输入区
        while (statc == std::future_status::timeout) {
            lk.unlock();
            statc = needallread.wait_for(var,1ms);
            lk.lock();
        }
        //输出区 设置为buf开始 重新写入
        setp(&buffer.front(), &buffer.back());
        *pptr() = ch;
        pbump(1);
        //输出区指针已更新
        needallwriter.set(true);
        return 100;//不为eof即可
    }
private:
public:  
    inline const StringTpye& CurrentMemory() const { return buffer; }
    Syncstreambuf(size_t  buffersize)
    {
        buffer.resize(buffersize, 0);
        Buftype::setg(&buffer.front(), &buffer.front(), &buffer.front());//输入区设置
        Buftype::setp(&buffer.front(), &buffer.back());//输出区设置
    }
};
int main() {
    std::locale::global(std::locale(""));
    Syncstreambuf bufferc(4);
    std::thread thoutput([&bufferc]() {
        std::istream iut(&bufferc);

        while (true)
        {
            std::string sadasd;
            iut >> sadasd;
            std::cout << "输出::" << sadasd.length() << ";context:" << sadasd << std::endl;
        }
        }
    );
    std::thread thread([&bufferc]() {
        std::ostream out(&bufferc);
        std::string sadasd = "1234567890TESTZXCVBNMPOL12345";
        while (true) {
            std::cout << "输入::" << sadasd.length() << ";context:" << sadasd <<
                std::endl;
            out << sadasd << std::endl;
            std::this_thread::sleep_for(1200.0ms);
        }
        }

    );
    thread.detach();
    thoutput.join();
}