Index: common/city.c
===================================================================
RCS file: /home/freeciv/CVS/freeciv/common/city.c,v
retrieving revision 1.163
diff -u -r1.163 city.c
--- common/city.c	2002/07/15 19:30:58	1.163
+++ common/city.c	2002/07/25 10:32:17
@@ -1062,7 +1062,7 @@
 /**************************************************************************
 ...
 **************************************************************************/
-struct city *city_list_find_name(struct city_list *This, char *name)
+struct city *city_list_find_name(struct city_list *This, const char *name)
 {
   struct genlist_iterator myiter;
 
Index: common/city.h
===================================================================
RCS file: /home/freeciv/CVS/freeciv/common/city.h,v
retrieving revision 1.110
diff -u -r1.110 city.h
--- common/city.h	2002/07/15 17:06:22	1.110
+++ common/city.h	2002/07/25 10:32:18
@@ -408,7 +408,7 @@
 
 /* list functions */
 struct city *city_list_find_id(struct city_list *This, int id);
-struct city *city_list_find_name(struct city_list *This, char *name);
+struct city *city_list_find_name(struct city_list *This, const char *name);
 
 int city_name_compare(const void *p1, const void *p2);
 
Index: common/game.c
===================================================================
RCS file: /home/freeciv/CVS/freeciv/common/game.c,v
retrieving revision 1.142
diff -u -r1.142 game.c
--- common/game.c	2002/07/15 19:30:59	1.142
+++ common/game.c	2002/07/25 10:32:18
@@ -544,7 +544,7 @@
 /**************************************************************************
 ...
 **************************************************************************/
-struct city *game_find_city_by_name(char *name)
+struct city *game_find_city_by_name(const char *name)
 {
   players_iterate(pplayer) {
     struct city *pcity = city_list_find_name(&pplayer->cities, name);
@@ -711,6 +711,7 @@
   game.randseed=GAME_DEFAULT_RANDSEED;
   game.watchtower_vision=GAME_DEFAULT_WATCHTOWER_VISION;
   game.watchtower_extra_vision=GAME_DEFAULT_WATCHTOWER_EXTRA_VISION,
+  game.allowed_city_names = GAME_DEFAULT_ALLOWED_CITY_NAMES;
 
   sz_strlcpy(game.rulesetdir, GAME_DEFAULT_RULESETDIR);
 
Index: common/game.h
===================================================================
RCS file: /home/freeciv/CVS/freeciv/common/game.h,v
retrieving revision 1.108
diff -u -r1.108 game.h
--- common/game.h	2002/07/15 19:30:59	1.108
+++ common/game.h	2002/07/25 10:32:19
@@ -155,6 +155,7 @@
 
   int watchtower_extra_vision;
   int watchtower_vision;
+  int allowed_city_names;
 
   char rulesetdir[MAX_LEN_NAME];
   int firepower_factor;		/* See README.rulesets */
@@ -231,7 +232,7 @@
 void game_advance_year(void);
 
 int civ_population(struct player *pplayer);
-struct city *game_find_city_by_name(char *name);
+struct city *game_find_city_by_name(const char *name);
 
 struct unit *find_unit_by_id(int id);
 struct city *find_city_by_id(int id);
@@ -449,6 +450,10 @@
 #define GAME_DEFAULT_WATCHTOWER_EXTRA_VISION 0
 #define GAME_MIN_WATCHTOWER_EXTRA_VISION 0
 #define GAME_MAX_WATCHTOWER_EXTRA_VISION 2
+
+#define GAME_DEFAULT_ALLOWED_CITY_NAMES 1
+#define GAME_MIN_ALLOWED_CITY_NAMES 0
+#define GAME_MAX_ALLOWED_CITY_NAMES 3
 
 #define GAME_START_YEAR -4000
 
Index: server/cityhand.c
===================================================================
RCS file: /home/freeciv/CVS/freeciv/server/cityhand.c,v
retrieving revision 1.114
diff -u -r1.114 cityhand.c
--- server/cityhand.c	2002/06/12 07:24:48	1.114
+++ server/cityhand.c	2002/07/25 10:32:19
@@ -386,14 +386,19 @@
     return;
   }
 
-  if((cp=get_sane_name(preq->name))) {
-    /* more sanity tests! any existing city with that name? */
-    sz_strlcpy(pcity->name, cp);
-    city_refresh(pcity);
-    send_city_info(NULL, pcity);
-  } else {
+  cp = get_sane_name(preq->name);
+  if (!cp) {
     notify_player(pplayer, _("Game: %s is not a valid name."), preq->name);
+    return;
   }
+
+  if (!is_allowed_city_name(pplayer, cp, pcity->x, pcity->y, TRUE)) {
+    return;
+  }
+
+  sz_strlcpy(pcity->name, cp);
+  city_refresh(pcity);
+  send_city_info(NULL, pcity);
 }
 
 /**************************************************************************
Index: server/citytools.c
===================================================================
RCS file: /home/freeciv/CVS/freeciv/server/citytools.c,v
retrieving revision 1.183
diff -u -r1.183 citytools.c
--- server/citytools.c	2002/07/03 07:59:02	1.183
+++ server/citytools.c	2002/07/25 10:32:21
@@ -55,7 +55,8 @@
 static int evaluate_city_name_priority(int x, int y,
 				       struct city_name *city_name,
 				       int default_priority);
-static char *search_for_city_name(int x, int y, struct city_name *city_names);
+static char *search_for_city_name(int x, int y, struct city_name *city_names,
+				  struct player *pplayer);
 static void server_set_tile_city(struct city *pcity, int city_x, int city_y,
 				 enum city_tile_type type);
 
@@ -145,6 +146,24 @@
   return (int)priority;	
 }
 
+/**************************************************************************
+Checks if a city name belongs to default city names of a particular
+player.
+**************************************************************************/
+static bool is_default_city_name(const char *name, struct player *pplayer)
+{
+  struct nation_type *nation = get_nation_by_plr(pplayer);
+  int choice;
+
+  for (choice = 0; nation->city_names[choice].name; choice++) {
+    if (mystrcasecmp(name, nation->city_names[choice].name) == 0) {
+      return TRUE;
+    }
+  }
+
+  return FALSE;
+}
+
 /****************************************************************
 Searches through a city name list (a struct city_name array)
 to pick the best available city name, and returns a pointer to
@@ -153,19 +172,21 @@
 city name.  If the list has no valid entries in it, NULL will be
 returned.
 *****************************************************************/
-static char *search_for_city_name(int x, int y, struct city_name *city_names)
+static char *search_for_city_name(int x, int y, struct city_name *city_names,
+				  struct player *pplayer)
 {
   int choice, best_priority = -1;
   char* best_name = NULL;
 
   for (choice = 0; city_names[choice].name; choice++) {
-    if (!game_find_city_by_name(city_names[choice].name)) {
+    if (!game_find_city_by_name(city_names[choice].name) &&
+	is_allowed_city_name(pplayer, city_names[choice].name, x, y, FALSE)) {
       int priority = evaluate_city_name_priority(x, y, &city_names[choice],
-					         choice);
+						 choice);
 
       if (best_priority == -1 || priority < best_priority) {
-        best_priority = priority;
-        best_name = city_names[choice].name;
+	best_priority = priority;
+	best_name = city_names[choice].name;
       }
     }
   }
@@ -173,6 +194,75 @@
   return best_name;
 }
 
+/**************************************************************************
+Checks, if a city name is allowed for a player. If not, reports a
+reason for rejection. There's 4 different modes:
+0: no restrictions,
+1: a city name has to be unique to player
+2: a city name has to be globally unique
+3: a city name has to be globally unique, and players can't use names
+   that are in another player's default city names. (E.g. Swedish may not
+   call new cities or rename old cities as Helsinki, because it's in
+   Finns' default city names)
+**************************************************************************/
+bool is_allowed_city_name(struct player *pplayer, const char *city_name,
+			  int x, int y, bool notify_player)
+{
+  /* Mode 0: No restrictions to city names */
+  if (game.allowed_city_names == 0) {
+    return TRUE;
+  }
+
+  /* Mode 1: A city name has to be unique to player */
+  if (game.allowed_city_names == 1 &&
+      city_list_find_name(&pplayer->cities, city_name)) {
+    if (notify_player) {
+      notify_player_ex(pplayer, x, y, E_NOEVENT,
+		       _("Game: You already have a city called %s"),
+		       city_name);
+    }
+    return FALSE;
+  }
+
+  /* 
+   * Mode 3: Check first that the proposed city name is not in another
+   * player's default city names.
+   */
+  if (game.allowed_city_names == 3) {
+    struct player *pother = NULL;
+
+    players_iterate(player2) {
+      if (player2 != pplayer && is_default_city_name(city_name, player2)) {
+	pother = player2;
+	break;
+      }
+    } players_iterate_end;
+
+    if (pother != NULL) {
+      if (notify_player) {
+	notify_player_ex(pplayer, x, y, E_NOEVENT,
+			 _("Game: Can't use %s as a city name. "
+			   "It is reserved for %s."),
+			 city_name, get_nation_name_plural(pother->nation));
+      }
+      return FALSE;
+    }
+  }
+
+  /* Modes 2,3: A city name has to be globally unique */
+  if ((game.allowed_city_names == 2 ||
+       game.allowed_city_names == 3) && game_find_city_by_name(city_name)) {
+    if (notify_player) {
+      notify_player_ex(pplayer, x, y, E_NOEVENT,
+		       _("Game: A city called %s already exists."),
+		       city_name);
+    }
+    return FALSE;
+  }
+
+  return TRUE;
+}
+
 /****************************************************************
 Come up with a default name when a new city is about to be built.
 Handle running out of names etc. gracefully.  Maybe we should keep
@@ -197,13 +287,12 @@
   
   CHECK_MAP_POS(x,y);
 
-  /* coastal */
-  name = search_for_city_name(x, y, nation->city_names);
+  name = search_for_city_name(x, y, nation->city_names, pplayer);
   if (name) {
     return name;
   }
 
-  name = search_for_city_name(x, y, misc_city_names);
+  name = search_for_city_name(x, y, misc_city_names, pplayer);
   if (name) {
     return name;
   }
@@ -841,6 +930,7 @@
   struct player *pgiver = city_owner(pcity);
   int old_trade_routes[NUM_TRADEROUTES];
   bool had_palace = pcity->improvements[B_PALACE] != I_NONE;
+  char old_city_name[MAX_LEN_NAME];
 
   assert(pgiver != ptaker);
 
@@ -865,6 +955,17 @@
 
   give_citymap_from_player_to_player(pcity, pgiver, ptaker);
   map_unfog_pseudo_city_area(ptaker, pcity->x, pcity->y);
+
+  sz_strlcpy(old_city_name, pcity->name);
+  if (game.allowed_city_names == 1 &&
+      city_list_find_name(&ptaker->cities, pcity->name)) {
+    sz_strlcpy(pcity->name,
+	       city_name_suggestion(ptaker, pcity->x, pcity->y));
+    notify_player_ex(ptaker, pcity->x, pcity->y, E_NOEVENT,
+		     _("You already had a city called %s."
+		       " The city was renamed to %s."), old_city_name,
+		     pcity->name);
+  }
 
   /* Has to follow the unfog call above. */
   city_list_unlink(&pgiver->cities, pcity);
Index: server/citytools.h
===================================================================
RCS file: /home/freeciv/CVS/freeciv/server/citytools.h,v
retrieving revision 1.39
diff -u -r1.39 citytools.h
--- server/citytools.h	2002/04/30 12:52:58	1.39
+++ server/citytools.h	2002/07/25 10:32:21
@@ -80,6 +80,8 @@
 void change_build_target(struct player *pplayer, struct city *pcity, 
 			 int target, bool is_unit, int event);
 
+bool is_allowed_city_name(struct player *pplayer, const char *city_name,
+			  int x, int y, bool notify_player);
 char *city_name_suggestion(struct player *pplayer, int x, int y);
 extern struct city_name *misc_city_names;
 
Index: server/savegame.c
===================================================================
RCS file: /home/freeciv/CVS/freeciv/server/savegame.c,v
retrieving revision 1.83
diff -u -r1.83 savegame.c
--- server/savegame.c	2002/07/15 19:31:01	1.83
+++ server/savegame.c	2002/07/25 10:32:22
@@ -1822,6 +1822,9 @@
 						   "game.occupychance");
     game.randseed = secfile_lookup_int_default(file, game.randseed,
 					       "game.randseed");
+    game.allowed_city_names =
+	secfile_lookup_int_default(file, game.allowed_city_names,
+				   "game.allowed_city_names"); 
 
     if(game.civstyle == 1) {
       string = "civ1";
@@ -2147,6 +2150,7 @@
   secfile_insert_str(file, game.demography, "game.demography");
   secfile_insert_int(file, game.watchtower_vision, "game.watchtower_vision");
   secfile_insert_int(file, game.watchtower_extra_vision, "game.watchtower_extra_vision");
+  secfile_insert_int(file, game.allowed_city_names, "game.allowed_city_names");
 
   if (TRUE) {
     /* Now always save these, so the server options reflect the
Index: server/stdinhand.c
===================================================================
RCS file: /home/freeciv/CVS/freeciv/server/stdinhand.c,v
retrieving revision 1.236
diff -u -r1.236 stdinhand.c
--- server/stdinhand.c	2002/07/23 19:24:08	1.236
+++ server/stdinhand.c	2002/07/25 10:32:25
@@ -543,6 +543,19 @@
 	  GAME_MIN_WATCHTOWER_EXTRA_VISION, GAME_MAX_WATCHTOWER_EXTRA_VISION, 
 	  GAME_DEFAULT_WATCHTOWER_EXTRA_VISION)
 
+  GEN_INT("citynames", game.allowed_city_names, SSET_RULES, SSET_TO_CLIENT,
+	  N_("Allowed city names"),
+	  N_("If set to 0, there are no restrictions: players can have "
+	     "multiple cities with the same names. "
+	     "If set to 1, city names have to be unique to a player: "
+	     "one player can't have multiple cities with the same name. "
+	     "If set to 2 or 3, city names have to be globally unique: "
+	     "all cities in a game have to have different names. "
+	     "If set to 3, a player isn't allowed to use a default city name "
+	     "of another nations."),NULL,
+	  GAME_MIN_ALLOWED_CITY_NAMES, GAME_MAX_ALLOWED_CITY_NAMES, 
+	  GAME_DEFAULT_ALLOWED_CITY_NAMES)
+  
 /* Flexible rules: these can be changed after the game has started.
  *
  * The distinction between "rules" and "flexible rules" is not always
Index: server/unithand.c
===================================================================
RCS file: /home/freeciv/CVS/freeciv/server/unithand.c,v
retrieving revision 1.228
diff -u -r1.228 unithand.c
--- server/unithand.c	2002/07/18 08:58:59	1.228
+++ server/unithand.c	2002/07/25 10:32:26
@@ -532,13 +532,18 @@
 		       char *name)
 {
   char *city_name = get_sane_name(name);
-
+ 
   if (!city_name) {
     notify_player_ex(pplayer, punit->x, punit->y, E_NOEVENT,
 		     _("Game: Let's not build a city with "
 		       "such a stupid name."));
     return;
   }
+
+  if (!is_allowed_city_name(pplayer, city_name, punit->x, punit->y, TRUE)) {
+    return;
+  }
+
   create_city(pplayer, punit->x, punit->y, city_name);
   wipe_unit(punit);
 }