(svn r10205) -Codechange: refactor returning of cost, so it can be more easily modified.

4 files changed, 47 insertions, 45 deletions

diff --git a/src/ai/ai.cpp b/src/ai/ai.cpp
index ec8837f2c..8086ef29a 100644
--- a/src/ai/ai.cpp
+++ b/src/ai/ai.cpp
@@ -84,7 +84,7 @@ static void AI_PutCommandInQueue(PlayerID player, TileIndex tile, uint32 p1, uin
 CommandCost AI_DoCommandCc(TileIndex tile, uint32 p1, uint32 p2, uint32 flags, uint procc, CommandCallback* callback)
 {
 	PlayerID old_lp;
-	CommandCost res = 0;
+	CommandCost res;
 	const char* tmp_cmdtext;
 
 	/* If you enable DC_EXEC with DC_QUERY_COST you are a really strange
diff --git a/src/ai/default/default.cpp b/src/ai/default/default.cpp
index d5d3922c8..a5bc10514 100644
--- a/src/ai/default/default.cpp
+++ b/src/ai/default/default.cpp
@@ -152,7 +152,7 @@ static EngineID AiChooseTrainToBuild(RailType railtype, int32 money, byte flag,
 		}
 
 		ret = DoCommand(tile, i, 0, 0, CMD_BUILD_RAIL_VEHICLE);
-		if (CmdSucceeded(ret) && ret <= money && rvi->ai_rank >= best_veh_score) {
+		if (CmdSucceeded(ret) && ret.GetCost() <= money && rvi->ai_rank >= best_veh_score) {
 			best_veh_score = rvi->ai_rank;
 			best_veh_index = i;
 		}
@@ -189,8 +189,8 @@ static EngineID AiChooseRoadVehToBuild(CargoID cargo, int32 money, TileIndex til
 		if (CmdFailed(ret)) continue;
 
 		/* Add the cost of refitting */
-		if (rvi->cargo_type != cargo) ret += GetRefitCost(i);
-		if (ret > money) continue;
+		if (rvi->cargo_type != cargo) ret.AddCost(GetRefitCost(i));
+		if (ret.GetCost() > money) continue;
 
 		best_veh_rating = rating;
 		best_veh_index = i;
@@ -216,8 +216,8 @@ static EngineID AiChooseAircraftToBuild(int32 money, byte flag)
 		if ((AircraftVehInfo(i)->subtype & AIR_CTOL) != flag) continue;
 
 		ret = DoCommand(0, i, 0, DC_QUERY_COST, CMD_BUILD_AIRCRAFT);
-		if (CmdSucceeded(ret) && ret <= money && ret >= best_veh_cost) {
-			best_veh_cost = ret;
+		if (CmdSucceeded(ret) && ret.GetCost() <= money && ret.GetCost() >= best_veh_cost) {
+			best_veh_cost = ret.GetCost();
 			best_veh_index = i;
 		}
 	}
@@ -1641,7 +1641,7 @@ static bool AiCheckTrackResources(TileIndex tile, const AiDefaultBlockData *p, b
 static CommandCost AiDoBuildDefaultRailTrack(TileIndex tile, const AiDefaultBlockData* p, RailType railtype, byte flag)
 {
 	CommandCost ret;
-	CommandCost total_cost = 0;
+	CommandCost total_cost;
 	Town *t = NULL;
 	int rating = 0;
 	int i, j, k;
@@ -1662,7 +1662,7 @@ static CommandCost AiDoBuildDefaultRailTrack(TileIndex tile, const AiDefaultBloc
 			}
 
 			if (CmdFailed(ret)) return CMD_ERROR;
-			total_cost += ret;
+			total_cost.AddCost(ret);
 
 clear_town_stuff:;
 			if (_cleared_town != NULL) {
@@ -1684,7 +1684,7 @@ clear_town_stuff:;
 					k = i;
 					ret = DoCommand(c, railtype, i, flag | DC_AUTO | DC_NO_WATER, CMD_BUILD_SINGLE_RAIL);
 					if (CmdFailed(ret)) return CMD_ERROR;
-					total_cost += ret;
+					total_cost.AddCost(ret);
 				}
 			}
 
@@ -1699,17 +1699,18 @@ clear_town_stuff:;
 						ret = DoCommand(c, k, 0, flag, CMD_BUILD_SIGNALS);
 					} while (--j);
 				} else {
-					ret = _price.build_signals;
+					ret.AddCost(_price.build_signals);
 				}
 				if (CmdFailed(ret)) return CMD_ERROR;
-				total_cost += ret;
+				total_cost.AddCost(ret);
 			}
 		} else if (p->mode == 3) {
 			//Clear stuff and then build single rail.
 			if (GetTileSlope(c, NULL) != SLOPE_FLAT) return CMD_ERROR;
 			ret = DoCommand(c, 0, 0, flag | DC_AUTO | DC_NO_WATER | DC_AI_BUILDING, CMD_LANDSCAPE_CLEAR);
 			if (CmdFailed(ret)) return CMD_ERROR;
-			total_cost += ret + _price.build_rail;
+			total_cost.AddCost(ret);
+			total_cost.AddCost(_price.build_rail);
 
 			if (flag & DC_EXEC) {
 				DoCommand(c, railtype, p->attr & 1, flag | DC_AUTO | DC_NO_WATER | DC_AI_BUILDING, CMD_BUILD_SINGLE_RAIL);
@@ -2069,7 +2070,7 @@ static inline void AiCheckBuildRailTunnelHere(AiRailFinder *arf, TileIndex tile,
 	if (GetTileSlope(tile, &z) == _dir_table_2[p[0] & 3] && z != 0) {
 		CommandCost cost = DoCommand(tile, arf->player->ai.railtype_to_use, 0, DC_AUTO, CMD_BUILD_TUNNEL);
 
-		if (CmdSucceeded(cost) && cost <= (arf->player->player_money >> 4)) {
+		if (CmdSucceeded(cost) && cost.GetCost() <= (arf->player->player_money >> 4)) {
 			AiBuildRailRecursive(arf, _build_tunnel_endtile, p[0] & 3);
 			if (arf->depth == 1) AiCheckRailPathBetter(arf, p);
 		}
@@ -2210,8 +2211,8 @@ static void AiBuildRailConstruct(Player *p)
 		 */
 		for (i = MAX_BRIDGES - 1; i != 0; i--) {
 			if (CheckBridge_Stuff(i, bridge_len)) {
-				int32 cost = DoCommand(arf.bridge_end_tile, p->ai.cur_tile_a, i | (p->ai.railtype_to_use << 8), DC_AUTO, CMD_BUILD_BRIDGE);
-				if (CmdSucceeded(cost) && cost < (p->player_money >> 5)) break;
+				CommandCost cost = DoCommand(arf.bridge_end_tile, p->ai.cur_tile_a, i | (p->ai.railtype_to_use << 8), DC_AUTO, CMD_BUILD_BRIDGE);
+				if (CmdSucceeded(cost) && cost.GetCost() < (p->player_money >> 5)) break;
 			}
 		}
 
@@ -2629,7 +2630,7 @@ static int AiFindBestDefaultRoadBlock(TileIndex tile, byte direction, byte cargo
 static CommandCost AiDoBuildDefaultRoadBlock(TileIndex tile, const AiDefaultBlockData *p, byte flag)
 {
 	CommandCost ret;
-	CommandCost total_cost = 0;
+	CommandCost total_cost;
 	Town *t = NULL;
 	int rating = 0;
 	int roadflag = 0;
@@ -2651,7 +2652,7 @@ static CommandCost AiDoBuildDefaultRoadBlock(TileIndex tile, const AiDefaultBloc
 
 			ret = DoCommand(c, p->attr, 0, flag | DC_AUTO | DC_NO_WATER, CMD_BUILD_ROAD);
 			if (CmdFailed(ret)) return CMD_ERROR;
-			total_cost += ret;
+			total_cost.AddCost(ret);
 
 			continue;
 		}
@@ -2671,7 +2672,7 @@ static CommandCost AiDoBuildDefaultRoadBlock(TileIndex tile, const AiDefaultBloc
 clear_town_stuff:;
 
 			if (CmdFailed(ret)) return CMD_ERROR;
-			total_cost += ret;
+			total_cost.AddCost(ret);
 
 			if (_cleared_town != NULL) {
 				if (t != NULL && t != _cleared_town) return CMD_ERROR;
@@ -2969,7 +2970,7 @@ static inline void AiCheckBuildRoadTunnelHere(AiRoadFinder *arf, TileIndex tile,
 	if (GetTileSlope(tile, &z) == _dir_table_2[p[0] & 3] && z != 0) {
 		CommandCost cost = DoCommand(tile, 0x200, 0, DC_AUTO, CMD_BUILD_TUNNEL);
 
-		if (CmdSucceeded(cost) && cost <= (arf->player->player_money >> 4)) {
+		if (CmdSucceeded(cost) && cost.GetCost() <= (arf->player->player_money >> 4)) {
 			AiBuildRoadRecursive(arf, _build_tunnel_endtile, p[0] & 3);
 			if (arf->depth == 1)  AiCheckRoadPathBetter(arf, p);
 		}
@@ -3102,7 +3103,7 @@ do_some_terraform:
 		for (i = 10; i != 0; i--) {
 			if (CheckBridge_Stuff(i, bridge_len)) {
 				CommandCost cost = DoCommand(tile, p->ai.cur_tile_a, i + ((0x80 | ROADTYPES_ROAD) << 8), DC_AUTO, CMD_BUILD_BRIDGE);
-				if (CmdSucceeded(cost) && cost < (p->player_money >> 5)) break;
+				if (CmdSucceeded(cost) && cost.GetCost() < (p->player_money >> 5)) break;
 			}
 		}
 
@@ -3390,13 +3391,13 @@ static void AiStateAirportStuff(Player *p)
 static CommandCost AiDoBuildDefaultAirportBlock(TileIndex tile, const AiDefaultBlockData *p, byte flag)
 {
 	uint32 avail_airports = GetValidAirports();
-	CommandCost total_cost = 0, ret;
+	CommandCost total_cost, ret;
 
 	for (; p->mode == 0; p++) {
 		if (!HASBIT(avail_airports, p->attr)) return CMD_ERROR;
 		ret = DoCommand(TILE_MASK(tile + ToTileIndexDiff(p->tileoffs)), p->attr, 0, flag | DC_AUTO | DC_NO_WATER, CMD_BUILD_AIRPORT);
 		if (CmdFailed(ret)) return CMD_ERROR;
-		total_cost += ret;
+		total_cost.AddCost(ret);
 	}
 
 	return total_cost;
diff --git a/src/ai/trolly/build.cpp b/src/ai/trolly/build.cpp
index 25b7ebd8d..41c80529c 100644
--- a/src/ai/trolly/build.cpp
+++ b/src/ai/trolly/build.cpp
@@ -97,7 +97,7 @@ CommandCost AiNew_Build_RoutePart(Player *p, Ai_PathFinderInfo *PathFinderInfo,
 	TileIndex *route = PathFinderInfo->route;
 	int dir;
 	int old_dir = -1;
-	CommandCost cost = 0;
+	CommandCost cost;
 	CommandCost res;
 	// We need to calculate the direction with the parent of the parent.. so we skip
 	//  the first pieces and the last piece
@@ -105,30 +105,30 @@ CommandCost AiNew_Build_RoutePart(Player *p, Ai_PathFinderInfo *PathFinderInfo,
 	// When we are done, stop it
 	if (part >= PathFinderInfo->route_length - 1) {
 		PathFinderInfo->position = -2;
-		return 0;
+		return CommandCost();
 	}
 
 
 	if (PathFinderInfo->rail_or_road) {
 		// Tunnel code
 		if ((AI_PATHFINDER_FLAG_TUNNEL & route_extra[part]) != 0) {
-			cost += AI_DoCommand(route[part], 0, 0, flag, CMD_BUILD_TUNNEL);
+			cost.AddCost(AI_DoCommand(route[part], 0, 0, flag, CMD_BUILD_TUNNEL));
 			PathFinderInfo->position++;
 			// TODO: problems!
 			if (CmdFailed(cost)) {
 				DEBUG(ai, 0, "[BuildPath] tunnel could not be built (0x%X)", route[part]);
-				return 0;
+				return CommandCost();
 			}
 			return cost;
 		}
 		// Bridge code
 		if ((AI_PATHFINDER_FLAG_BRIDGE & route_extra[part]) != 0) {
-			cost += AiNew_Build_Bridge(p, route[part], route[part - 1], flag);
+			cost.AddCost(AiNew_Build_Bridge(p, route[part], route[part - 1], flag));
 			PathFinderInfo->position++;
 			// TODO: problems!
 			if (CmdFailed(cost)) {
 				DEBUG(ai, 0, "[BuildPath] bridge could not be built (0x%X, 0x%X)", route[part], route[part - 1]);
-				return 0;
+				return CommandCost();
 			}
 			return cost;
 		}
@@ -147,9 +147,9 @@ CommandCost AiNew_Build_RoutePart(Player *p, Ai_PathFinderInfo *PathFinderInfo,
 				if (CmdFailed(res)) {
 					// Problem.. let's just abort it all!
 					p->ainew.state = AI_STATE_NOTHING;
-					return 0;
+					return CommandCost();
 				}
-				cost += res;
+				cost.AddCost(res);
 				// Go to the next tile
 				part++;
 				// Check if it is still in range..
@@ -162,23 +162,23 @@ CommandCost AiNew_Build_RoutePart(Player *p, Ai_PathFinderInfo *PathFinderInfo,
 	} else {
 		// Tunnel code
 		if ((AI_PATHFINDER_FLAG_TUNNEL & route_extra[part]) != 0) {
-			cost += AI_DoCommand(route[part], 0x200 | ROADTYPES_ROAD, 0, flag, CMD_BUILD_TUNNEL);
+			cost.AddCost(AI_DoCommand(route[part], 0x200 | ROADTYPES_ROAD, 0, flag, CMD_BUILD_TUNNEL));
 			PathFinderInfo->position++;
 			// TODO: problems!
 			if (CmdFailed(cost)) {
 				DEBUG(ai, 0, "[BuildPath] tunnel could not be built (0x%X)", route[part]);
-				return 0;
+				return CommandCost();
 			}
 			return cost;
 		}
 		// Bridge code
 		if ((AI_PATHFINDER_FLAG_BRIDGE & route_extra[part]) != 0) {
-			cost += AiNew_Build_Bridge(p, route[part], route[part + 1], flag);
+			cost.AddCost(AiNew_Build_Bridge(p, route[part], route[part + 1], flag));
 			PathFinderInfo->position++;
 			// TODO: problems!
 			if (CmdFailed(cost)) {
 				DEBUG(ai, 0, "[BuildPath] bridge could not be built (0x%X, 0x%X)", route[part], route[part + 1]);
-				return 0;
+				return CommandCost();
 			}
 			return cost;
 		}
@@ -203,10 +203,10 @@ CommandCost AiNew_Build_RoutePart(Player *p, Ai_PathFinderInfo *PathFinderInfo,
 						// Problem.. let's just abort it all!
 						DEBUG(ai, 0, "[BuidPath] route building failed at tile 0x%X, aborting", route[part]);
 						p->ainew.state = AI_STATE_NOTHING;
-						return 0;
+						return CommandCost();
 					}
 
-					if (CmdSucceeded(res)) cost += res;
+					if (CmdSucceeded(res)) cost.AddCost(res);
 				}
 				// Go to the next tile
 				part++;
@@ -314,11 +314,12 @@ CommandCost AiNew_Build_Depot(Player* p, TileIndex tile, DiagDirection direction
 		return AI_DoCommand(tile, 0, direction, flag | DC_AUTO | DC_NO_WATER, CMD_BUILD_TRAIN_DEPOT);
 	} else {
 		ret = AI_DoCommand(tile, direction, 0, flag | DC_AUTO | DC_NO_WATER, CMD_BUILD_ROAD_DEPOT);
-		if (CmdFailed(ret)) return ret;
+		if (CmdFailed(ret2)) return ret;
 		// Try to build the road from the depot
 		ret2 = AI_DoCommand(tile + TileOffsByDiagDir(direction), DiagDirToRoadBits(ReverseDiagDir(direction)), 0, flag | DC_AUTO | DC_NO_WATER, CMD_BUILD_ROAD);
 		// If it fails, ignore it..
 		if (CmdFailed(ret2)) return ret;
-		return ret + ret2;
+		ret.AddCost(ret2);
+		return ret;
 	}
 }
diff --git a/src/ai/trolly/trolly.cpp b/src/ai/trolly/trolly.cpp
index f0e3e2500..fb0263d41 100644
--- a/src/ai/trolly/trolly.cpp
+++ b/src/ai/trolly/trolly.cpp
@@ -691,7 +691,7 @@ static void AiNew_State_FindStation(Player *p)
 
 		// See how much it is going to cost us...
 		r = AiNew_Build_Station(p, p->ainew.tbt, new_tile, 0, 0, 0, DC_QUERY_COST);
-		p->ainew.new_cost += r;
+		p->ainew.new_cost += r.GetCost();
 
 		direction = AI_PATHFINDER_NO_DIRECTION;
 	} else if (new_tile == 0 && p->ainew.tbt == AI_TRUCK) {
@@ -850,7 +850,7 @@ static void AiNew_State_FindDepot(Player *p)
 				r = AiNew_Build_Depot(p, t, ReverseDiagDir(j), 0);
 				if (CmdFailed(r)) continue;
 				// Found a spot!
-				p->ainew.new_cost += r;
+				p->ainew.new_cost += r.GetCost();
 				p->ainew.depot_tile = t;
 				p->ainew.depot_direction = ReverseDiagDir(j); // Reverse direction
 				p->ainew.state = AI_STATE_VERIFY_ROUTE;
@@ -935,7 +935,7 @@ static void AiNew_State_VerifyRoute(Player *p)
 
 	do {
 		p->ainew.path_info.position++;
-		p->ainew.new_cost += AiNew_Build_RoutePart(p, &p->ainew.path_info, DC_QUERY_COST);
+		p->ainew.new_cost += AiNew_Build_RoutePart(p, &p->ainew.path_info, DC_QUERY_COST).GetCost();
 	} while (p->ainew.path_info.position != -2);
 
 	// Now we know the price of build station + path. Now check how many vehicles
@@ -951,7 +951,7 @@ static void AiNew_State_VerifyRoute(Player *p)
 
 	// Check how much it it going to cost us..
 	for (i=0;i<res;i++) {
-		p->ainew.new_cost += AiNew_Build_Vehicle(p, 0, DC_QUERY_COST);
+		p->ainew.new_cost += AiNew_Build_Vehicle(p, 0, DC_QUERY_COST).GetCost();
 	}
 
 	// Now we know how much the route is going to cost us
@@ -985,7 +985,7 @@ static void AiNew_State_VerifyRoute(Player *p)
 // Build the stations
 static void AiNew_State_BuildStation(Player *p)
 {
-	CommandCost res = 0;
+	CommandCost res;
 	assert(p->ainew.state == AI_STATE_BUILD_STATION);
 	if (p->ainew.temp == 0) {
 		if (!IsTileType(p->ainew.from_tile, MP_STATION))
@@ -1103,7 +1103,7 @@ static void AiNew_State_BuildPath(Player *p)
 // Builds the depot
 static void AiNew_State_BuildDepot(Player *p)
 {
-	CommandCost res = 0;
+	CommandCost res;
 	assert(p->ainew.state == AI_STATE_BUILD_DEPOT);
 
 	if (IsTileType(p->ainew.depot_tile, MP_STREET) && GetRoadTileType(p->ainew.depot_tile) == ROAD_TILE_DEPOT) {
@@ -1278,7 +1278,7 @@ static void AiNew_CheckVehicle(Player *p, Vehicle *v)
 
 			if (!AiNew_SetSpecialVehicleFlag(p, v, AI_VEHICLEFLAG_SELL)) return;
 			{
-				CommandCost ret = 0;
+				CommandCost ret;
 				if (v->type == VEH_ROAD)
 					ret = AI_DoCommand(0, v->index, 0, DC_EXEC, CMD_SEND_ROADVEH_TO_DEPOT);
 				// This means we can not find a depot :s