[spanbuf.general] (original) (raw)

31 Input/output library [input.output]

31.9 Span-based streams [span.streams]

31.9.3 Class template basic_spanbuf [spanbuf]

31.9.3.1 General [spanbuf.general]

namespace std { template<class charT, class traits = char_traits<charT>> class basic_spanbuf: public basic_streambuf<charT, traits> { public: using char_type = charT;using int_type = typename traits::int_type;using pos_type = typename traits::pos_type;using off_type = typename traits::off_type;using traits_type = traits; basic_spanbuf() : basic_spanbuf(ios_base::in | ios_base::out) {} explicit basic_spanbuf(ios_base::openmode which) : basic_spanbuf(std::span<charT>(), which) {} explicit basic_spanbuf(std::span<charT> s, ios_base::openmode which = ios_base::in | ios_base::out); basic_spanbuf(const basic_spanbuf&) = delete; basic_spanbuf(basic_spanbuf&& rhs); basic_spanbuf& operator=(const basic_spanbuf&) = delete; basic_spanbuf& operator=(basic_spanbuf&& rhs);void swap(basic_spanbuf& rhs); std::span<charT> span() const noexcept;void span(std::span<charT> s) noexcept;protected: basic_streambuf<charT, traits>* setbuf(charT*, streamsize) override; pos_type seekoff(off_type off, ios_base::seekdir way, ios_base::openmode which = ios_base::in | ios_base::out) override; pos_type seekpos(pos_type sp, ios_base::openmode which = ios_base::in | ios_base::out) override;private: ios_base::openmode mode; std::span<charT> buf; };}

The class template basic_spanbuf is derived from basic_streambufto associate possibly the input sequence and possibly the output sequence with a sequence of arbitrary characters.

The sequence is provided by an object of class span<charT>.

For the sake of exposition, the maintained data is presented here as:

• ios_base​::​openmode mode, hasin set if the input sequence can be read, andout set if the output sequence can be written.
• std​::​span<charT> buf is the view to the underlying character sequence.