Class TStringOutput

util/stream/str.h:64–105

* Stream for writing data into a string. */

 * Stream for writing data into a string.
 */
class TStringOutput: public IZeroCopyOutput {
public:
    /**
     * Constructs a string output stream that appends character data to the
     * provided string.
     *
     * Note that this stream keeps a reference to the provided string, so it's
     * up to the user to make sure that the string doesn't get destroyed while
     * this stream is in use.
     *
     * @param s                         String to append to.
     */
    inline TStringOutput(TString& s Y_LIFETIME_BOUND) noexcept
        : S_(&s)
    {
    }

    TStringOutput(TStringOutput&& s) noexcept = default;

    ~TStringOutput() override;

    /**
     * @param size                      Number of additional characters to
     *                                  reserve in output string.
     */
    inline void Reserve(size_t size) {
        S_->reserve(S_->size() + size);
    }

    inline void Swap(TStringOutput& s) noexcept {
        DoSwap(S_, s.S_);
    }

protected:
    size_t DoNext(void** ptr) override;
    void DoUndo(size_t len) override;
    void DoWrite(const void* buf, size_t len) override;
    void DoWriteC(char c) override;

private:
    TString* S_;
};

/**
 * String input/output stream, similar to `std::stringstream`.