[Freeciv-Dev] (PR#9466) check direction in mapstep

["Jason Short" <jdorje@xxxxxxxxxxxxxxxxxxxxx>]

<URL: http://rt.freeciv.org/Ticket/Display.html?id=9466 >

For hex maps MAPSTEP needs to verify that the direction is valid.  This 
patch calls is_valid_dir to do that.

This slows down MAPSTEP significantly since is_valid_dir is an extra 
function call (it could easily be made inline/macro, but I doubt it's 
worth it).  But MAPSTEP isn't used very often so this shouldn't have a 
measurable effect on runtime.

This is the last cleanup necessary for hex-maps.

jason

Index: common/map.h
===================================================================
RCS file: /home/freeciv/CVS/freeciv/common/map.h,v
retrieving revision 1.198
diff -u -r1.198 map.h
--- common/map.h        21 Jul 2004 14:46:59 -0000      1.198
+++ common/map.h        21 Jul 2004 14:56:03 -0000
@@ -329,9 +329,10 @@
  * we bend this rule here.
  */
 #define MAPSTEP(dest_x, dest_y, src_x, src_y, dir)     \
-(    (dest_x) = (src_x) + DIR_DX[(dir)],               \
-     (dest_y) = (src_y) + DIR_DY[(dir)],               \
-     normalize_map_pos(&(dest_x), &(dest_y)))
+  (is_valid_dir(dir)                                    \
+   && ((dest_x) = (src_x) + DIR_DX[(dir)],             \
+       (dest_y) = (src_y) + DIR_DY[(dir)],             \
+       normalize_map_pos(&(dest_x), &(dest_y))))
 
 struct player *map_get_owner(int x, int y);
 void map_set_owner(int x, int y, struct player *pplayer);