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

[Gregory Berkolaiko <Gregory.Berkolaiko@xxxxxxxxxxxx>]

Quoting Raimar Falke <rf13@xxxxxxxxxxxxxxxxx>:

> On Fri, Feb 21, 2003 at 10:25:22PM +0000, Gregory Berkolaiko wrote:
> > > > > > +   */
> > > > > > +  int (*get_MC) (int from_x, int from_y, enum direction8 dir,
> > > > > > +            int to_x, int to_y, void *);
> > > > > 
> > > > > We should also supply "known".
> > > > 
> > > > When any user code needs it, it will be added.
> > > 
> > > Based on this we would have to remove this parameter also from the
> > > other callbacks. It should be added here and also to is_pos_dangerous.
> > 
> > Definitely add to is_pos_dangerous, I am surprised it's not there yet.
> > Definitely not here.  I am not having it just for uniformity's sake.  
> > This is a back-bone of the whole module and +- one byte makes a difference.
> 
> > Give me a problem that requires "known" here and cannot be solved by
> existing
> > call-backs and then we can negotiate.
> 
> This one extra argument is one extra push for the caller. Thats it. No
> other cost. gcc doesn't pop but just adjusts the %esp directly. And it
> has no influence on the called function (if the function doesn't use
> it). I expect that a push is fast. Very fast since you need it
> everytime you call a function.

Don't push it on me, man!
Since you are not giving me the example that needs it, we will assume that none
such exists.

> > While waiting for comments, I can suggest an alternative: return a negative
> number.
> 
> This is slightly better. But still not clean.

Cleaner than the way you suggest.

> > > Yes but the above starts to make exceptions. What about leaving the
> > > *_data fields and passing the param struct * into the callback instead
> > > of the _data pointers. This way the callback have both the "normal"
> > > fields of the parameter and also the special _data fields.
> > 
> > Makes good sense.  Shall we cut down number of *data fields?  If needed
> *data
> > can point to a struct with more data.
> 
> You mean cut down to one?

Yep.

G.