Hello Vinnie,

thanks for your reply

On Thu, May 24, 2018 at 5:22 PM, Vinnie Falco via Boost-users <boost-users@lists.boost.org> wrote:

However, let me propose a wild idea. Set your current code aside for
the moment and reimplement it a different way. Instead of doing three
asynchronous reads, call async_read_some once into your
basic_streambuf. Use a reasonably large size in the call to prepare
(say, 2048 or higher). When you have data in your buffer, inspect the
contents and determine if you have a complete message. If not, then
keep looping and calling async_read_some until your buffer has an
entire message. Then extract the message, consume the bytes used, and
repeat. When extracting the bytes do not use asynchronous I/O.

Not a wild idea at all. Yet a see a two problems with it.

This pretty much means taking over what asio calls 'composed operations' myself. Instead of letting asio do read_some calls and figure out when I have, say, a line completely read (until CRL), I read and figure it out myself. Which is very much what I wanted to avoid by going the streambuf approach in the first place.

The second issue to me is the inspection of the contents. The packets are of variable size and can theoretically (though not practically) range up to about 64k. I don't know how large the payload is until I read and parsed the header. Which means I would hav to do just that: Inspect the contents of the buffer. Which I have no idea how to do. Over the years, this is not the first time I'm trying this approach and I always folded when it came to inspecting the contents of a streambuf. I simply don't know how this can be done. I can't even reliably do it in the debugger. Sure, I see data but which is input and which is output and where are all those position markers and what would I really get if I read...

I guess you are right though. An new implementation using fixed buffers would probably solve the bug as well. As it always did in the past. I guess I just wanted to be fancy again.

Thanks for your suggestion...

Stephan