[Freeciv-Dev] Re: packet_conn_ping_info and connections

[Anthony Stuckey <stuckey@xxxxxxxxxxxxx>]

Jason Dorje Short wrote:

> Andreas Røsdal wrote:
>
> > On Tue, 19 Oct 2004, Mike Kaufman wrote:
> >
> > > On Tue, Oct 19, 2004 at 02:33:27PM -0400, Jason Dorje Short wrote:
> > >
> > > > packet_conn_ping_info assumes there can be no more than 
> > > > MAX_NUM_PLAYERS
> > > > connections.  Is this a safe assumption?  It seems unlikely.
> > >
> > > this is absolutely wrong.
> > >
> > > sernet.h:
> > >
> > > #define MAX_NUM_CONNECTIONS (2 * (MAX_NUM_PLAYERS + 
> > > MAX_NUM_BARBARIANS))
> > > the 2 there was put in by me, but it's really arbitrary. For a really
> > > exciting game (league finals?), you might want to have a great many
> > > observers. We might want to raise it sometime in the future.
> >
> > Why should there be a limit to the number of connections? Also, why 
> > should
> > there be a limit to the number of players?
>
> 1.  Assumptions in the code.
>
> 2.  Limitations in the network code (arrays must be bounded).
>
> If the first were fixed then MAX_NUM_PLAYERS could be made much 
> larger.  MAX_NUM_CONNECTIONS could easily be larger.  However without 
> redesigning the network packets or the core network code there must be 
> _some_ limitation.
> The most common code assumption is that 
> MAX_NUM_PLAYERS+MAX_NUM_BARBARIANS<=32.  4-byte bitfields are used for 
> players.  However this has been fixed in a number of places already.
> jason
Limitting the number of players can also be important for game balance 
reasons.  Things like the Great Library become more effective with an 
increasing number of players.  Modpack authors need to be aware of this 
kind of scalability problem.