(svn r4826) -Fix: [autoreplace] fixed possible problem when autoreplacing and was number of vehicles (of a type, not total) was reached

	now the new vehicle gets the same number as the old one, completely removing the problem where we could run out of numbers
	since we don't have to find free numbers for the new vehicles, autoreplace should be somewhat faster, specially in late games
	NOTE: in CmdBuildRailVehicle(), bit 0 and 1 in p2 have been switched to make the meaning of bit 0 consistent with the other build commands. CmdCloneVehicle() is modified to follow this as well

5 files changed, 18 insertions, 20 deletions

diff --git a/aircraft_cmd.c b/aircraft_cmd.c
index 54b881537..fd7dad834 100644
--- a/aircraft_cmd.c
+++ b/aircraft_cmd.c
@@ -158,7 +158,7 @@ static int32 EstimateAircraftCost(EngineID engine_type)
 /** Build an aircraft.
  * @param tile tile of depot where aircraft is built
  * @param p1 aircraft type being built (engine)
- * @param p2 unused
+ * @param p2 bit 0 when set, the unitnumber will be 0, otherwise it will be a free number
  */
 int32 CmdBuildAircraft(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
 {
@@ -186,7 +186,7 @@ int32 CmdBuildAircraft(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
 		return_cmd_error(STR_00E1_TOO_MANY_VEHICLES_IN_GAME);
 	}
 
-	unit_num = GetFreeUnitNumber(VEH_Aircraft);
+	unit_num = (HASBIT(p2, 0) == true) ? 0 : GetFreeUnitNumber(VEH_Aircraft);
 	if (unit_num > _patches.max_aircraft)
 		return_cmd_error(STR_00E1_TOO_MANY_VEHICLES_IN_GAME);
 
diff --git a/roadveh_cmd.c b/roadveh_cmd.c
index c9d1176f8..963f635ec 100644
--- a/roadveh_cmd.c
+++ b/roadveh_cmd.c
@@ -103,7 +103,7 @@ static int32 EstimateRoadVehCost(EngineID engine_type)
 /** Build a road vehicle.
  * @param tile tile of depot where road vehicle is built
  * @param p1 bus/truck type being built (engine)
- * @param p2 unused
+ * @param p2 bit 0 when set, the unitnumber will be 0, otherwise it will be a free number
  */
 int32 CmdBuildRoadVeh(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
 {
@@ -129,7 +129,7 @@ int32 CmdBuildRoadVeh(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
 		return_cmd_error(STR_00E1_TOO_MANY_VEHICLES_IN_GAME);
 
 	/* find the first free roadveh id */
-	unit_num = GetFreeUnitNumber(VEH_Road);
+	unit_num = (HASBIT(p2, 0) == true) ? 0 : GetFreeUnitNumber(VEH_Road);
 	if (unit_num > _patches.max_roadveh)
 		return_cmd_error(STR_00E1_TOO_MANY_VEHICLES_IN_GAME);
 
diff --git a/ship_cmd.c b/ship_cmd.c
index 3cb66e430..1d6e1383d 100644
--- a/ship_cmd.c
+++ b/ship_cmd.c
@@ -811,7 +811,7 @@ void ShipsYearlyLoop(void)
 /** Build a ship.
  * @param tile tile of depot where ship is built
  * @param p1 ship type being built (engine)
- * @param p2 unused
+ * @param p2 bit 0 when set, the unitnumber will be 0, otherwise it will be a free number
  */
 int32 CmdBuildShip(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
 {
@@ -833,8 +833,9 @@ int32 CmdBuildShip(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
 	if (!IsTileOwner(tile, _current_player)) return CMD_ERROR;
 
 	v = AllocateVehicle();
-	if (v == NULL || IsOrderPoolFull() ||
-			(unit_num = GetFreeUnitNumber(VEH_Ship)) > _patches.max_ships)
+	unit_num = (HASBIT(p2, 0) == true) ? 0 : GetFreeUnitNumber(VEH_Ship);
+
+	if (v == NULL || IsOrderPoolFull() || unit_num > _patches.max_ships)
 		return_cmd_error(STR_00E1_TOO_MANY_VEHICLES_IN_GAME);
 
 	if (flags & DC_EXEC) {
diff --git a/train_cmd.c b/train_cmd.c
index 81cccfc04..35f5d41af 100644
--- a/train_cmd.c
+++ b/train_cmd.c
@@ -699,8 +699,8 @@ static void AddRearEngineToMultiheadedTrain(Vehicle* v, Vehicle* u, bool buildin
 /** Build a railroad vehicle.
  * @param tile tile of the depot where rail-vehicle is built
  * @param p1 engine type id
- * @param p2 bit 0 prevents any free cars from being added to the train
- *           bit 1 when set, the train will get number 0, otherwise it will get a free number
+ * @param p2 bit 0 when set, the train will get number 0, otherwise it will get a free number
+ *           bit 1 prevents any free cars from being added to the train
  */
 int32 CmdBuildRailVehicle(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
 {
@@ -744,14 +744,10 @@ int32 CmdBuildRailVehicle(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
 
 		v = vl[0];
 
-		if (HASBIT(p2, 1)) {
-			// no number is needed, so we assign 0. The engine is likely intended for a train with more than one engine
-			unit_num = 0;
-		} else {
-			unit_num = GetFreeUnitNumber(VEH_Train);
-			if (unit_num > _patches.max_trains)
-				return_cmd_error(STR_00E1_TOO_MANY_VEHICLES_IN_GAME);
-		}
+		unit_num = (HASBIT(p2, 0) == true) ? 0 : GetFreeUnitNumber(VEH_Train);
+		if (unit_num > _patches.max_trains)
+			return_cmd_error(STR_00E1_TOO_MANY_VEHICLES_IN_GAME);
+
 		if (flags & DC_EXEC) {
 			DiagDirection dir = GetRailDepotDirection(tile);
 			int x = TileX(tile) * TILE_SIZE + _vehicle_initial_x_fract[dir];
@@ -815,7 +811,7 @@ int32 CmdBuildRailVehicle(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
 			TrainConsistChanged(v);
 			UpdateTrainAcceleration(v);
 
-			if (!HASBIT(p2, 0)) {	// check if the cars should be added to the new vehicle
+			if (!HASBIT(p2, 1)) {	// check if the cars should be added to the new vehicle
 				NormalizeTrainVehInDepot(v);
 			}
 
diff --git a/vehicle.c b/vehicle.c
index 9404a6db2..3d1103014 100644
--- a/vehicle.c
+++ b/vehicle.c
@@ -1490,7 +1490,7 @@ int32 CmdCloneVehicle(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
 	Vehicle *v_front, *v;
 	Vehicle *w_front, *w, *w_rear;
 	int cost, total_cost = 0;
-	uint32 build_argument = 1;
+	uint32 build_argument = 2;
 
 	if (!IsVehicleIndex(p1)) return CMD_ERROR;
 	v = GetVehicle(p1);
@@ -1624,7 +1624,7 @@ static int32 ReplaceVehicle(Vehicle **w, byte flags)
 	new_engine_type = EngineReplacementForPlayer(p, old_v->engine_type);
 	if (new_engine_type == INVALID_ENGINE) new_engine_type = old_v->engine_type;
 
-	cost = DoCommand(old_v->tile, new_engine_type, 1, flags, CMD_BUILD_VEH(old_v->type));
+	cost = DoCommand(old_v->tile, new_engine_type, 3, flags, CMD_BUILD_VEH(old_v->type));
 	if (CmdFailed(cost)) return cost;
 
 	if (flags & DC_EXEC) {
@@ -1660,6 +1660,7 @@ static int32 ReplaceVehicle(Vehicle **w, byte flags)
 			new_v->profit_last_year = old_v->profit_last_year;
 			new_v->service_interval = old_v->service_interval;
 			new_front = true;
+			new_v->unitnumber = old_v->unitnumber;	// use the same unit number
 
 			new_v->current_order = old_v->current_order;
 			if (old_v->type == VEH_Train && GetNextVehicle(old_v) != NULL){