Re: [Boost-users] file descriptor imitation - boost iostreams

From: eg (egoots_at_[hidden])
Date: 2007-12-14 02:54:52

Micha³ Nowotka wrote:
> Hi Boosters,
> 
> I have a function with following interface:
> 
> int gvRender (GVC_t *gvc, graph_t *g, char *format, FILE *out)
> 
> but I don't want to store the output in temporary file but to compute
> everything in memory... (but to store the output to same malloced
> string and pass it to a display function). Boost is so powerful - so
> can I solve this problem somehow using boost (C++ doesn't doesn't
> provide tools to simulate file descriptors )? I know very little about
> boost iostream would it be helpful?
> 

Not sure if it is what you want, but you could look at 
container_device_example.cpp in libs\iostreams\example

For example we could do something like this to write a zipped and 
encrypted stream of data into a std::string ...

io::filtering_ostream out;
out.push( io::gzip_compressor()  );
out.push( CryptFilter(key) );
std::string	memString;
out.push ( container_sink<std::string> (memString));
WriteStuff(out); // this writes stuff to the stream
out.reset(); // flush it

At this point the stuff is in the memString.