Index: common/map.c
===================================================================
RCS file: /home/freeciv/CVS/freeciv/common/map.c,v
retrieving revision 1.92
diff -u -r1.92 map.c
--- common/map.c	2001/09/27 22:49:52	1.92
+++ common/map.c	2001/09/28 00:03:26
@@ -1287,11 +1287,6 @@
   return 1;
 }
 
-int is_real_tile(int x, int y)
-{
-  return 0 <= y && y < map.ysize;
-}
-
 /**************************************************************************
 Normalizes the map position. Returns TRUE if it is real, FALSE otherwise.
 **************************************************************************/
Index: common/map.h
===================================================================
RCS file: /home/freeciv/CVS/freeciv/common/map.h,v
retrieving revision 1.94
diff -u -r1.94 map.h
--- common/map.h	2001/09/27 22:49:53	1.94
+++ common/map.h	2001/09/28 00:03:27
@@ -213,6 +213,9 @@
      (dest_y) += (src_y),   				\
      normalize_map_pos(&(dest_x), &(dest_y)))
 
+#define is_real_tile(x,y) \
+  (IN_RANGE((y), map.ysize))
+
 struct city *map_get_city(int x, int y);
 void map_set_city(int x, int y, struct city *pcity);
 enum tile_terrain_type map_get_terrain(int x, int y);
@@ -223,7 +226,6 @@
 void tile_init(struct tile *ptile);
 enum known_type tile_is_known(int x, int y);
 int check_coords(int *x, int *y);
-int is_real_tile(int x, int y);
 int normalize_map_pos(int *x, int *y);
 void nearest_real_pos(int *x, int *y);
 
Index: common/shared.h
===================================================================
RCS file: /home/freeciv/CVS/freeciv/common/shared.h,v
retrieving revision 1.87
diff -u -r1.87 shared.h
--- common/shared.h	2001/09/15 21:25:12	1.87
+++ common/shared.h	2001/09/28 00:03:28
@@ -59,6 +59,19 @@
 
 #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
 
+/* We're using a trick here.  The straightforward way to write
+IN_RANGE() would be as
+
+  0 <= (a) && (a) < b
+
+however, since we know that b is always positive and we know
+that the bit-pattern of a negative signed int is the same as the
+bit-pattern of a very large number when interpreted as an unsigned
+int, we can do away with the extra check.  */
+
+#define IN_RANGE(a,b) \
+  (((unsigned) (a)) < ((unsigned) (b)))
+
 char *create_centered_string(char *s);
 
 char * get_option(const char *option_name,char **argv,int *i,int argc);