[Freeciv-Dev] Re: bug in mapgen (PR#1043)

["Ross W. Wetmore" <rwetmore@xxxxxxxxxxxx>]

I would delete the lines. I don't think they are actually used after
this point, but I didn't do an exhaustive check. Create_island() resets
them each time, and when you leave at this point you aren't looping
back to place_island().

Since they are (badly named) globals anybody could access them, but it
isn't really likely.

Cheers,
RossW
=====

At 07:50 AM 01/10/31 -0800, jdorje@xxxxxxxxxxxxxxxxxxxxx wrote:
>There is a bug in map generators 3 and 4 (or 2 and 3, depending on your
>numbering) that causes the creation of non-normal, out-of-bounds
>coordiantes.  This happens in place_island(); after the main body of the
>function the rectangle defined by the n,s,e,w variables is translated to
>have its origin at the randomly found new position.  However no checking
>is done to see if this newly formed rectangle is entirely within the
>"normal" region.
>
>The attached patch provides a simple fix for this.  This may not be the
>correct fix, but the code there now is pretty certainly a bug.  Ross,
>how would you fix it?
>
>jasonIndex: server/mapgen.c
>===================================================================
>RCS file: /home/freeciv/CVS/freeciv/server/mapgen.c,v
>retrieving revision 1.76
>diff -u -r1.76 mapgen.c
>--- server/mapgen.c    2001/10/30 10:59:20     1.76
>+++ server/mapgen.c    2001/10/31 15:45:32
>@@ -1586,8 +1586,8 @@
>         i++;
>       }
>     }
>-  s += yo - n;
>-  e += xo - w;
>+  s = MIN(yo + (s - n), map.ysize-1);
>+  e = MIN(xo + (e - w), map.xsize-1);
>   n = yo;
>   w = xo;
>   return i;
>