[Freeciv-Dev] (PR#9360) restricting nations in scenarios

["Jason Dorje Short" <jdorje@xxxxxxxxxxx>]

<URL: http://rt.freeciv.org/Ticket/Display.html?id=9360 >

For a scenario that lists a nation for every starting position, the 
nations available should be restricted to just those nations.

This patch accomplishes that.  It includes PR#9359.

It also has some problems since most GUIs restrict nations by 
deselecting or crossing out the used nations.  But for nations 
unavailable from the start they should just not be shown.  This can 
probably be dealt with by expanding the boolean "available" nation value 
into an enumeration or pair of booleans.

jason

Index: server/srv_main.c
===================================================================
RCS file: /home/freeciv/CVS/freeciv/server/srv_main.c,v
retrieving revision 1.173
diff -u -r1.173 srv_main.c
--- server/srv_main.c   12 Jul 2004 21:35:00 -0000      1.173
+++ server/srv_main.c   12 Jul 2004 23:48:02 -0000
@@ -108,7 +108,7 @@
 static bool is_game_over(void);
 static void save_game_auto(void);
 static void generate_ai_players(void);
-static int mark_nation_as_used(int nation);
+static void mark_nation_as_used(Nation_Type_id nation);
 static void announce_ai_player(struct player *pplayer);
 static void send_select_nation(struct player *pplayer);
 static void srv_loop(void);
@@ -131,11 +131,8 @@
 */
 bool force_end_of_sniff;
 
-
-/* The next three variables make selecting nations for AI players cleaner */
-static int *nations_avail;
-static int *nations_used;
-static int num_nations_avail;
+/* List of which nations are available. */
+static bool *nations_available;
 
 /* this counter creates all the id numbers used */
 /* use get_next_id_number()                     */
@@ -1091,17 +1088,16 @@
 static void send_select_nation(struct player *pplayer)
 {
   struct packet_nation_unavailable packet;
+  Nation_Type_id nation;
 
   lsend_packet_select_races(&pplayer->connections);
 
-  players_iterate(other_player) {
-    if (other_player->nation == NO_NATION_SELECTED) {
-      continue;
+  for (nation = 0; nation < game.playable_nation_count; nation++) {
+    if (!nations_available[nation]) {
+      packet.nation = nation;
+      lsend_packet_nation_unavailable(&pplayer->connections, &packet);
     }
-
-    packet.nation = other_player->nation;
-    lsend_packet_nation_unavailable(&pplayer->connections, &packet);
-  } players_iterate_end;
+  }
 }
 
 /**************************************************************************
@@ -1138,33 +1134,33 @@
 **************************************************************************/
 static Nation_Type_id select_random_nation(const char* class)
 {
-  Nation_Type_id* nations, selected;
-  int i, j;
-  
-  if (class == NULL) {
-    return nations_avail[myrand(num_nations_avail)];
-  }
-  
-  nations = fc_malloc(num_nations_avail * sizeof(*nations));
-  for (j = i = 0; i < num_nations_avail; i++) {
-    struct nation_type* nation = get_nation_by_idx(nations_avail[i]);
+  Nation_Type_id i, available[game.playable_nation_count];
+  int count = 0;
 
-    assert(nation->class != NULL);
-    if (strcmp(nation->class, class) == 0) {
-      nations[j++] = nations_avail[i];
+  /* Determine which nations are available. */
+  for (i = 0; i < game.playable_nation_count; i++) {
+    struct nation_type *nation = get_nation_by_idx(i);
+
+    if (nations_available[i]
+       && (class == NULL || strcmp(nation->class, class) == 0)) {
+      available[count] = i;
+      count++;
     }
   }
 
-  if (j == 0) {
-    /* Pick any available nation. */
-    selected = nations_avail[myrand(num_nations_avail)];
-  } else {
-    selected = nations[myrand(j)];
-    assert(strcmp(get_nation_by_idx(selected)->class, class) == 0);
+  /* Handle the case where no nations are possible. */
+  if (count == 0) {
+    if (class) {
+      /* Try other classes. */
+      return select_random_nation(NULL);
+    }
+
+    /* Or else return an invalid value. */
+    return NO_NATION_SELECTED;
   }
 
-  free(nations);
-  return selected;
+  /* Then pick one. */
+  return available[myrand(count)];
 }
 
 /**************************************************************************
@@ -1208,10 +1204,23 @@
       continue;
     }
 
-    if (num_nations_avail == 0) {
+    /* See if the AI player matches a known leader name. */
+    for (nation = 0; nation < game.playable_nation_count; nation++) {
+      if (check_nation_leader_name(nation, pplayer->name)
+         && nations_available[nation]) {
+       mark_nation_as_used(nation);
+       pplayer->nation = nation;
+       pplayer->city_style = get_nation_city_style(nation);
+       pplayer->is_male = get_nation_leader_sex(nation, pplayer->name);
+       continue;
+      }
+    }
+
+    nation = select_random_nation(common_class);
+    if (nation == NO_NATION_SELECTED) {
       freelog(LOG_NORMAL,
              _("Ran out of nations.  AI controlled player %s not created."),
-             pplayer->name );
+             pplayer->name);
       server_remove_player(pplayer); 
       /*
        * Below decrement loop index 'i' so that the loop is redone with
@@ -1221,23 +1230,10 @@
        */
       i--;  
       continue;
-    }
-
-    for (nation = 0; nation < game.playable_nation_count; nation++) {
-      if (check_nation_leader_name(nation, pplayer->name)) {
-        if (nations_used[nation] != -1) {
-         pplayer->nation = mark_nation_as_used(nation);
-         pplayer->city_style = get_nation_city_style(nation);
-          pplayer->is_male = get_nation_leader_sex(nation, pplayer->name);
-         break;
-        }
-      }
-    }
-
-    if (nation == game.playable_nation_count) {
-      pplayer->nation =
-       mark_nation_as_used(select_random_nation(common_class));
-      pplayer->city_style = get_nation_city_style(pplayer->nation);
+    } else {
+      mark_nation_as_used(nation);
+      pplayer->nation = nation;
+      pplayer->city_style = get_nation_city_style(nation);
       pplayer->is_male = (myrand(2) == 1);
     }
 
@@ -1270,7 +1266,9 @@
   }
 
   for(;game.nplayers < game.aifill;) {
-    nation = mark_nation_as_used(select_random_nation(common_class));
+    nation = select_random_nation(common_class);
+    assert(nation != NO_NATION_SELECTED);
+    mark_nation_as_used(nation);
     pick_ai_player_name(nation, player_name);
 
     old_nplayers = game.nplayers;
@@ -1360,23 +1358,12 @@
 }
 
 /*************************************************************************
- mark_nation_as_used() - shuffles the appropriate arrays to indicate that
- the specified nation number has been allocated to some player and is
- therefore no longer available to any other player.  We do things this way
- so that the process of determining which nations are available to AI players
- is more efficient.
+  Simply mark the nation as unavailable.
 *************************************************************************/
-static int mark_nation_as_used (int nation) 
+static void mark_nation_as_used (Nation_Type_id nation) 
 {
-  if (num_nations_avail <= 0) {        /* no more unused nation */
-    die("Argh! ran out of nations!");
-  }
-
-   nations_used[nations_avail[num_nations_avail-1]]=nations_used[nation];
-   nations_avail[nations_used[nation]]=nations_avail[--num_nations_avail];
-   nations_used[nation]=-1;
-
-   return nation;
+  assert(nations_available[nation]);
+  nations_available[nation] = FALSE;
 }
 
 /*************************************************************************
@@ -1579,6 +1566,7 @@
 static void srv_loop(void)
 {
   int i;
+  bool start_nations;
 
   freelog(LOG_NORMAL, _("Now accepting new client connections."));
   while(server_state == PRE_GAME_STATE) {
@@ -1592,17 +1580,39 @@
     /* otherwise rulesets were loaded when savegame was loaded */
   }
 
-  nations_avail = fc_calloc(game.playable_nation_count, sizeof(int));
-  nations_used = fc_calloc(game.playable_nation_count, sizeof(int));
+  nations_available
+    = fc_realloc(nations_available,
+                game.playable_nation_count * sizeof(*nations_available));
 
 main_start_players:
 
   send_rulesets(&game.game_connections);
 
-  num_nations_avail = game.playable_nation_count;
-  for (i = 0; i < game.playable_nation_count; i++) {
-    nations_avail[i] = i;
-    nations_used[i] = i;
+  if (map.num_start_positions > 0) {
+    start_nations = TRUE;
+
+    for (i = 0; i < map.num_start_positions; i++) {
+      if (map.start_positions[i].nation == NO_NATION_SELECTED) {
+       start_nations = FALSE;
+       break;
+      }
+    }
+  } else {
+    start_nations = FALSE;
+  }
+
+  if (start_nations) {
+    for (i = 0; i < game.playable_nation_count; i++) {
+      nations_available[i] = FALSE;
+    }
+    for (i = 0; i < map.num_start_positions; i++) {
+      nations_available[map.start_positions[i].nation] = TRUE;
+    }
+    
+  } else {
+    for (i = 0; i < game.playable_nation_count; i++) {
+      nations_available[i] = TRUE;
+    }
   }
 
   if (game.auto_ai_toggle) {