Class const_buffer

3rdparty/cppzmq/zmq.hpp:1122–1150

}

class const_buffer
{
  public:
    constexpr const_buffer() noexcept : _data(nullptr), _size(0) {}
    constexpr const_buffer(const void *p, size_t n) noexcept : _data(p), _size(n)
    {
#ifdef ZMQ_EXTENDED_CONSTEXPR
        assert(p != nullptr || n == 0);
#endif
    }
    constexpr const_buffer(const mutable_buffer &mb) noexcept :
        _data(mb.data()), _size(mb.size())
    {
    }

    constexpr const void *data() const noexcept { return _data; }
    constexpr size_t size() const noexcept { return _size; }
    const_buffer &operator+=(size_t n) noexcept
    {
        const auto shift = (std::min)(n, _size);
        _data = static_cast<const char *>(_data) + shift;
        _size -= shift;
        return *this;
    }

  private:
    const void *_data;
    size_t _size;
};

inline const_buffer operator+(const const_buffer &cb, size_t n) noexcept
{