"Frank B. Brokken" <f.b.brokken@xxxxxx> writes:
> class MultiStreambuf: public std::streambuf
> {
> public:
> enum Mode
> {
> OFF, // stream not used
> ON, // stream always used
> ONCE, // stream used until flushed
> RESET, // stream once used. Set to ONCE to re-use
> };
>
> class stream // holds a pointer to a stream and a indicator
> { // telling us whether or not to use the stream
> friend class MultiStreambuf;
>
> std::ostream *d_os;
> Mode d_mode;
>
> public:
> stream(std::ostream &os, Mode mode = ON);
> void setMode(Mode mode);
> Mode mode() const;
> std::ostream &ostream();
> private:
> static void setOnce(stream &os);
> };
>
> typedef std::vector<stream>::iterator iterator;
> typedef std::vector<stream>::const_iterator const_iterator;
>
> private:
> std::string d_buffer;
> std::vector<stream> d_os;
>
> public:
> MultiStreambuf() = default;
> explicit MultiStreambuf(std::ostream &os, Mode mode = ON);
> explicit MultiStreambuf(std::vector<stream> const &osvector);
>
> void insert(std::ostream &os, Mode mode = ON);
> void insert(std::vector<stream> const &os);
> iterator begin();
> iterator end();
> const_iterator begin() const;
> const_iterator end() const;
> void setOnce(); // reset all `RESET' modes to `ONCE'
>
> protected:
> int pSync();
>
> private:
> virtual int overflow(int c);
> virtual std::streamsize xsputn(char const *buffer, std::streamsize n);
> virtual int sync();
>
> struct Insert
> {
> std::string &buffer;
> bool ok;
> };
> static void insertStruct(stream &os, Insert &insert);
> };
OK, so the key method should be overflow.
> You won't see the implementations of the private virtual members here, as they
> are provided in the following header file, which is included by
> MultiStreambuf's sources:
>
> -------------------------------------------------------
> #include "multistreambuf"
>
> #include <algorithm>
> #include <bobcat/fnwrap>
>
> using namespace FBB;
>
> inline std::streamsize MultiStreambuf::xsputn(char const *buffer,
> std::streamsize n)
> {
> d_buffer.append(buffer, n);
> return n;
> }
>
> inline int MultiStreambuf::sync()
> {
> return pSync();
> }
>
> inline int MultiStreambuf::overflow(int c)
> {
> if (c == EOF)
> pSync();
> else
> d_buffer += c;
>
> return c;
> }
> -------------------------------------------------------
This approach will only work if you guarantee that every piece of code
that creates a new MultiStreambuf includes that header file.
> Since it looks like armel's compiler skips the inline definitions of virtual
> members when compiling for a shared library, we're in the process of removing
> all inline definitions of virtual members, replacing them by non-inline
> definitions in separate source files. From tests done so far by George Danchev
> we get the impression that this might very well solve (or bypass?) the issue.
Yes, that should work.
Ian
