c++ - 在 C++ 中是否有缓冲输出操作的标准解决方案？

Question

我编写了这个为一般输出操作提供缓冲的简单类:

template <typename T>
class WriteBuffer {
        typedef void (&flush_t)(const T* values, const size_t size);

    public:
        WriteBuffer(size_t size, flush_t flush) : flush_(flush) {
            v_.reserve(size);
        }

       ~WriteBuffer() { flush(); }

        void flush() {
            if (v_.size() > 0) {
                flush_(&v_[0], v_.size());
                v_.clear();
            }
        }

        void write(const T value) {
            if (v_.size() == v_.capacity())
                flush();
            v_.push_back(value);
        }

    private:
        vector<T> v_;
        flush_t flush_;
};

(为简单起见省略了错误检查。)以下示例程序:

void writeInt(const int* values, const size_t size) {
    cout << "Writing buffer of size " << size << ": " << endl;
    for (size_t i = 0; i < size; ++i)
        cout << values[i] << ", ";
    cout << endl;
}

int main(int argc, char* argv[]) {
    WriteBuffer<int> buffer(5, writeInt);

    for (size_t i = 0; i < 18; ++i)
        buffer.write(i);

    return 0;
}

然后生成以下输出:

Writing buffer of size 5: 0, 1, 2, 3, 4,Writing buffer of size 5: 5, 6, 7, 8, 9,Writing buffer of size 5: 10, 11, 12, 13, 14,Writing buffer of size 3: 15, 16, 17,

Is there any standard/better solution of this problem, e.g. some STL container / BOOST class with similar capabilities? Thanks!

Additional question: Would you prefer using function object instead of function reference flush_t?

EDIT

I would like to use such buffering for any type T and any flush operation provided by the client (not only characters and output streams). For example:

template <typename T>
void write(const T* values, const size_t size) {
    ...
    H5Dwrite(..., values);
    ...
}

WriteBuffer<unsigned long> buffer(8192, write<unsigned long>);

将数据写入 HDF5 数据集。 (这里不解决 HDF5 数据类型。)

Answer 1

标准解决方案是子类std::streambuf ，这正是为您的任务而设计的。有一些 boost magic以简化实现。