[boost] Overlapped IO usinig IOStreams library (was: re Compression usinig IOStreams library)

From: George M. Garner Jr. (gmgarner_at_[hidden])
Date: 2004-09-11 18:21:32

Johnathan,

> Now for some real fun.  I am going to try and attach an overlapped filebuf 
> to one of your
>> streams. :-)
>
> Good luck!
>

That worked without a hitch.  But that is only because my overlapped_filebuf 
uses blocking semantics.  My original goal was to be able to transparently 
interchange regular files and sockets as "sinks" and this will allow me to 
do that.  But the std stream and filebuf interfaces are really a 
straight-jacket when it comes to more advanced applications, such as truly 
asynchronous io; and the sooner we realize that the better.  Imagine if, for 
example, instead of doing write(char_type*, size_t) you could do 
write(ref_string<char_type>&) or 
write(ref_string_plus_overlapped<char_type>&).  An observer could 
transparently pass the buffer to the next layer without modification while 
an asynchronous sink could take ownership of buffer by calling a swap() 
member function and then pass the buffer to a waiting thread.  The buffer 
could grow or shrink as it passes from one filter to another.  The buffer 
could even pass in round robin fashion back to its origin if every observer 
or filter called swap() in turn.  But that is just a dream.

Regards,

George.