Re: [boost] decorated streambufs (was: Interest in library generating streambufs ...)

From: Larry Evans (jcampbell3_at_[hidden])
Date: 2003-06-15 08:31:31

Larry Evans wrote:
 > Larry Evans wrote:
 >
 > [snip]
 >
 >> Please see the just uploaded marg_ostreambuf.cpp for a
 >> little better version.
 >
 >
 > The just uploaded test_ostreambuf_decorator.zip contains
 > renamed classes as well as virtual {detach,attach}_ostream
 > to avoid using ostream* m_ostream==0 as flag indicating
 > the end of the chain of decorators.

The code mentioned MAY be very similar to that of J. Kanze available
at:

http://www.gabi-soft.fr/code/Util/IO/FilteringOutputStream/gb/FilteringOutputStream.hh

I say this because in the comments to the code, in class:

   class GB_FilteringOutputStreambufBase : public GB_iostd::streambuf

and after:

private:
     //      insert :
     //      --------

there's the following:

     //      Inserts a character into the destination.  This is where
     //      the actual filtering takes place.  The function receives
     //      the destination streambuf and the character as arguments;
     //      in case of error, it should return EOF, otherwise,
     //      anything else.  Exactly what it does with the character is
     //      upto the function in the derived class: it can pass it on
     //      to the destination, simply drop it, send a dozen or so
     //      other characters as well, or whatever it wants.

Since this is essentially what marg_ostreambuf does when it sees a
'\n' character( i.e. it outputs the margin before the next output
char) , I thought maybe this would be a better, more general, solution
to the problem solved by marg_ostreambuf and marg_ostream in:

   http://groups.yahoo.com/group/boost/files/col_io

What do other's think.  Would J. Kanze be interested and have time to
contribute this work to boost?