[Freeciv-Dev] Re: Path-finding code is in (PR#2370)

[Gregory Berkolaiko <Gregory.Berkolaiko@xxxxxxxxxxxx>]

Bringing discussion back to the list/RT...

On Thu, 13 Mar 2003, Raimar Falke wrote:

> On Thu, Mar 13, 2003 at 12:43:34PM +0000, Gregory Berkolaiko wrote:
> > > > Maybe it's time to change some functions in path_finding into macros 
> > > > again...
> > > 
> > > Please no.
> > 
> > Another thing to think about is recycling maps (i.e. not really freeing 
> > the memory in destroy_map and not allocating new memory in create_map)
> 
> I think that the user recycling should be done first. That is that the
> AI passed struct pf_map * around. This will work for the non-iterate
> case out of the box. For the iterate case we may have to add a
> pf_reset function.

I suspect you are talking about reusing generated maps.  This, of course, 
should be encouraged.

I was talking (actually it was Ross' idea) about reusing memory.  Since 
much time is spent on allocating big chunks, we can have a cache of 
several maps.

Right now:
1. A call to pf_create_map (a) allocates a map, (b) clears the memory and 
(c) initializes as appropriate.
2. A call to pf_destroy_map frees the memory.

Proposal:
1. A call to pf_create_map will (a) get a currently unused map from the 
cache, (b) clear the memory and (c) initialize as appropriate.
2. A call to pf_destroy_map will mark the map as unused.

This should be done under the hood, interface should not be changed.

G.