Re: In memory Stream

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On 2024-02-17 19:09, Simon Wright wrote:

> I can't remember at this distance in time, but I think I would have
> liked to construct a memory stream on the received UDP packet rather
> than copying the content; the compiler wouldn't let me. Perhaps worth
> another try.

UDP is a kind of thing... Basically, there is no use of UDP except for 
broadcasting, e.g. in LAN discovery.

In all other cases it is either TCP or multicast. Since UDP does not 
guarantee either delivery or ordering. It would be a huge overhead to 
implement reliable buffered streams on top of UDP, with sequence 
numbers, acknowledgements, re-sending, reordering etc.

As for taking apart a UDP packet, it is straightforward. You simply 
declare a stream element array of the packet size and map it on the 
packet using:

    pragma Import (Ada, A);
    for A'Address use UDP_Packet'Address;

And somewhere

    pragma Assert (Stream_Element'Size = 8);

just in case...

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de