(svn r14807) -Codechange: use INVALID_TILE instead of 0 to mark invalid depots, industries, towns and waypoints

15 files changed, 42 insertions, 32 deletions

diff --git a/src/build_vehicle_gui.cpp b/src/build_vehicle_gui.cpp
index 6ce2334df..7cfcc6aec 100644
--- a/src/build_vehicle_gui.cpp
+++ b/src/build_vehicle_gui.cpp
@@ -797,7 +797,7 @@ struct BuildVehicleWindow : Window {
 	EngineID rename_engine;
 	GUIEngineList eng_list;
 
-	BuildVehicleWindow(const WindowDesc *desc, TileIndex tile, VehicleType type) : Window(desc, tile == 0 ? (int)type : tile)
+	BuildVehicleWindow(const WindowDesc *desc, TileIndex tile, VehicleType type) : Window(desc, tile == INVALID_TILE ? (int)type : tile)
 	{
 		this->vehicle_type = type;
 		int vlh = GetVehicleListHeight(this->vehicle_type);
@@ -810,7 +810,7 @@ struct BuildVehicleWindow : Window {
 		this->resize.width  = this->width;
 		this->resize.height = this->height;
 
-		this->caption_color = (tile != 0) ? GetTileOwner(tile) : _local_company;
+		this->caption_color = (tile != INVALID_TILE) ? GetTileOwner(tile) : _local_company;
 
 		this->sel_engine      = INVALID_ENGINE;
 		this->regenerate_list = false;
@@ -821,15 +821,15 @@ struct BuildVehicleWindow : Window {
 		switch (type) {
 			default: NOT_REACHED();
 			case VEH_TRAIN:
-				this->filter.railtype = (tile == 0) ? RAILTYPE_END : GetRailType(tile);
+				this->filter.railtype = (tile == INVALID_TILE) ? RAILTYPE_END : GetRailType(tile);
 				break;
 			case VEH_ROAD:
-				this->filter.roadtypes = (tile == 0) ? ROADTYPES_ALL : GetRoadTypes(tile);
+				this->filter.roadtypes = (tile == INVALID_TILE) ? ROADTYPES_ALL : GetRoadTypes(tile);
 			case VEH_SHIP:
 				break;
 			case VEH_AIRCRAFT:
 				this->filter.flags =
-					tile == 0 ? AirportFTAClass::ALL : GetStationByTile(tile)->Airport()->flags;
+					tile == INVALID_TILE ? AirportFTAClass::ALL : GetStationByTile(tile)->Airport()->flags;
 				break;
 		}
 		this->SetupWindowStrings(type);
@@ -1194,10 +1194,10 @@ static const WindowDesc _build_vehicle_desc = {
 void ShowBuildVehicleWindow(TileIndex tile, VehicleType type)
 {
 	/* We want to be able to open both Available Train as Available Ships,
-	 *  so if tile == 0 (Available XXX Window), use 'type' as unique number.
+	 *  so if tile == INVALID_TILE (Available XXX Window), use 'type' as unique number.
 	 *  As it always is a low value, it won't collide with any real tile
 	 *  number. */
-	uint num = (tile == 0) ? (int)type : tile;
+	uint num = (tile == INVALID_TILE) ? (int)type : tile;
 
 	assert(IsCompanyBuildableVehicleType(type));
 
diff --git a/src/depot.cpp b/src/depot.cpp
index 8b9abe06a..005f067b1 100644
--- a/src/depot.cpp
+++ b/src/depot.cpp
@@ -43,7 +43,7 @@ Depot::~Depot()
 
 	/* Delete the depot-window */
 	DeleteWindowById(WC_VEHICLE_DEPOT, this->xy);
-	this->xy = 0;
+	this->xy = INVALID_TILE;
 }
 
 void InitializeDepots()
diff --git a/src/depot_base.h b/src/depot_base.h
index 35d35e392..53877485d 100644
--- a/src/depot_base.h
+++ b/src/depot_base.h
@@ -16,10 +16,10 @@ struct Depot : PoolItem<Depot, DepotID, &_Depot_pool> {
 	TileIndex xy;
 	TownID town_index;
 
-	Depot(TileIndex xy = 0) : xy(xy) {}
+	Depot(TileIndex xy = INVALID_TILE) : xy(xy) {}
 	~Depot();
 
-	inline bool IsValid() const { return this->xy != 0; }
+	inline bool IsValid() const { return this->xy != INVALID_TILE; }
 };
 
 static inline bool IsValidDepotID(DepotID index)
diff --git a/src/economy.cpp b/src/economy.cpp
index 6b8162608..a6fbb55f2 100644
--- a/src/economy.cpp
+++ b/src/economy.cpp
@@ -1313,7 +1313,7 @@ static bool CheckSubsidised(Station *from, Station *to, CargoID cargo_type)
 			if (cs->town_effect == TE_PASSENGERS || cs->town_effect == TE_MAIL) {
 				xy = GetTown(s->from)->xy;
 			} else {
-				xy = (GetIndustry(s->from))->xy;
+				xy = GetIndustry(s->from)->xy;
 			}
 			if (DistanceMax(xy, from->xy) > 9) continue;
 
diff --git a/src/group_gui.cpp b/src/group_gui.cpp
index e15a2f629..a59b7830c 100644
--- a/src/group_gui.cpp
+++ b/src/group_gui.cpp
@@ -535,7 +535,7 @@ public:
 
 
 			case GRP_WIDGET_AVAILABLE_VEHICLES:
-				ShowBuildVehicleWindow(0, this->vehicle_type);
+				ShowBuildVehicleWindow(INVALID_TILE, this->vehicle_type);
 				break;
 
 			case GRP_WIDGET_MANAGE_VEHICLES_DROPDOWN:
diff --git a/src/industry.h b/src/industry.h
index e750c6ab0..f154823a2 100644
--- a/src/industry.h
+++ b/src/industry.h
@@ -132,10 +132,10 @@ struct Industry : PoolItem<Industry, IndustryID, &_Industry_pool> {
 
 	PersistentStorage psa;              ///< Persistent storage for NewGRF industries.
 
-	Industry(TileIndex tile = 0) : xy(tile) {}
+	Industry(TileIndex tile = INVALID_TILE) : xy(tile) {}
 	~Industry();
 
-	inline bool IsValid() const { return this->xy != 0; }
+	inline bool IsValid() const { return this->xy != INVALID_TILE; }
 };
 
 struct IndustryTileTable {
diff --git a/src/industry_cmd.cpp b/src/industry_cmd.cpp
index 413a3aa81..d13cf5132 100644
--- a/src/industry_cmd.cpp
+++ b/src/industry_cmd.cpp
@@ -140,7 +140,7 @@ Industry::~Industry()
 	/* Industry can also be destroyed when not fully initialized.
 	 * This means that we do not have to clear tiles either. */
 	if (this->width == 0) {
-		this->xy = 0;
+		this->xy = INVALID_TILE;
 		return;
 	}
 
@@ -174,7 +174,7 @@ Industry::~Industry()
 	DeleteSubsidyWithIndustry(this->index);
 	DeleteWindowById(WC_INDUSTRY_VIEW, this->index);
 	InvalidateWindowData(WC_INDUSTRY_DIRECTORY, 0, 0);
-	this->xy = 0;
+	this->xy = INVALID_TILE;
 }
 
 static void IndustryDrawSugarMine(const TileInfo *ti)
diff --git a/src/oldloader.cpp b/src/oldloader.cpp
index a94824978..cb55afc50 100644
--- a/src/oldloader.cpp
+++ b/src/oldloader.cpp
@@ -490,7 +490,12 @@ static const OldChunks town_chunk[] = {
 };
 static bool LoadOldTown(LoadgameState *ls, int num)
 {
-	return LoadChunk(ls, new (num) Town(), town_chunk);
+	Town *t = new (num) Town();
+	if (!LoadChunk(ls, t, town_chunk)) return false;
+
+	if (t->xy == 0) t->xy = INVALID_TILE;
+
+	return true;
 }
 
 static uint16 _old_order;
@@ -545,10 +550,13 @@ static const OldChunks depot_chunk[] = {
 
 static bool LoadOldDepot(LoadgameState *ls, int num)
 {
-	if (!LoadChunk(ls, new (num) Depot(), depot_chunk)) return false;
+	Depot *d = new (num) Depot();
+	if (!LoadChunk(ls, d, depot_chunk)) return false;
 
-	if (IsValidDepotID(num)) {
+	if (d->xy != 0) {
 		GetDepot(num)->town_index = REMAP_TOWN_IDX(_old_town_index);
+	} else {
+		d->xy = INVALID_TILE;
 	}
 
 	return true;
@@ -732,9 +740,11 @@ static bool LoadOldIndustry(LoadgameState *ls, int num)
 	Industry *i = new (num) Industry();
 	if (!LoadChunk(ls, i, industry_chunk)) return false;
 
-	if (i->IsValid()) {
+	if (i->xy != 0) {
 		i->town = GetTown(REMAP_TOWN_IDX(_old_town_index));
 		IncIndustryTypeCount(i->type);
+	} else {
+		i->xy = INVALID_TILE;
 	}
 
 	return true;
diff --git a/src/order_gui.cpp b/src/order_gui.cpp
index a3a69d8a1..3f70a8c28 100644
--- a/src/order_gui.cpp
+++ b/src/order_gui.cpp
@@ -838,7 +838,7 @@ public:
 
 				if (_ctrl_pressed && sel < this->vehicle->GetNumOrders()) {
 					const Order *ord = GetVehicleOrder(this->vehicle, sel);
-					TileIndex xy = 0;
+					TileIndex xy = INVALID_TILE;
 
 					switch (ord->GetType()) {
 						case OT_GOTO_STATION:  xy = GetStation(ord->GetDestination())->xy ; break;
@@ -851,7 +851,7 @@ public:
 							break;
 					}
 
-					if (xy != 0) ScrollMainWindowToTile(xy);
+					if (xy != INVALID_TILE) ScrollMainWindowToTile(xy);
 					return;
 				}
 
diff --git a/src/town.h b/src/town.h
index f7f584b86..0e2b2221b 100644
--- a/src/town.h
+++ b/src/town.h
@@ -179,12 +179,12 @@ struct Town : PoolItem<Town, TownID, &_Town_pool> {
 	/**
 	 * Creates a new town
 	 */
-	Town(TileIndex tile = 0);
+	Town(TileIndex tile = INVALID_TILE);
 
 	/** Destroy the town */
 	~Town();
 
-	inline bool IsValid() const { return this->xy != 0; }
+	inline bool IsValid() const { return this->xy != INVALID_TILE; }
 
 	void InitializeLayout();
 
diff --git a/src/town_cmd.cpp b/src/town_cmd.cpp
index e37e331c1..ec318f488 100644
--- a/src/town_cmd.cpp
+++ b/src/town_cmd.cpp
@@ -65,7 +65,7 @@ DEFINE_OLD_POOL_GENERIC(Town, Town)
 
 Town::Town(TileIndex tile)
 {
-	if (tile != 0) _total_towns++;
+	if (tile != INVALID_TILE) _total_towns++;
 	this->xy = tile;
 }
 
@@ -115,7 +115,7 @@ Town::~Town()
 
 	MarkWholeScreenDirty();
 
-	this->xy = 0;
+	this->xy = INVALID_TILE;
 
 	UpdateNearestTownForRoadTiles(false);
 }
diff --git a/src/town_gui.cpp b/src/town_gui.cpp
index 4803e3bf2..c76556170 100644
--- a/src/town_gui.cpp
+++ b/src/town_gui.cpp
@@ -554,7 +554,7 @@ public:
 			while (i < this->towns.Length()) {
 				const Town *t = this->towns[i];
 
-				assert(t->xy);
+				assert(t->xy != INVALID_TILE);
 
 				SetDParam(0, t->index);
 				SetDParam(1, t->population);
@@ -601,7 +601,7 @@ public:
 				if (id_v >= this->towns.Length()) return; // click out of town bounds
 
 				const Town *t = this->towns[id_v];
-				assert(t->xy);
+				assert(t->xy != INVALID_TILE);
 				if (_ctrl_pressed) {
 					ShowExtraViewPortWindow(t->xy);
 				} else {
diff --git a/src/vehicle_gui.cpp b/src/vehicle_gui.cpp
index 6f5df3e62..a9133e611 100644
--- a/src/vehicle_gui.cpp
+++ b/src/vehicle_gui.cpp
@@ -1037,7 +1037,7 @@ struct VehicleListWindow : public BaseVehicleListWindow {
 			} break;
 
 			case VLW_WIDGET_AVAILABLE_VEHICLES:
-				ShowBuildVehicleWindow(0, this->vehicle_type);
+				ShowBuildVehicleWindow(INVALID_TILE, this->vehicle_type);
 				break;
 
 			case VLW_WIDGET_MANAGE_VEHICLES_DROPDOWN: {
diff --git a/src/waypoint.cpp b/src/waypoint.cpp
index a08e543c3..81d7d9563 100644
--- a/src/waypoint.cpp
+++ b/src/waypoint.cpp
@@ -460,7 +460,7 @@ Waypoint::~Waypoint()
 	RemoveOrderFromAllVehicles(OT_GOTO_WAYPOINT, this->index);
 
 	RedrawWaypointSign(this);
-	this->xy = 0;
+	this->xy = INVALID_TILE;
 }
 
 /**
diff --git a/src/waypoint.h b/src/waypoint.h
index a4afbba43..8b07bdbac 100644
--- a/src/waypoint.h
+++ b/src/waypoint.h
@@ -33,10 +33,10 @@ struct Waypoint : PoolItem<Waypoint, WaypointID, &_Waypoint_pool> {
 
 	byte deleted;      ///< Delete counter. If greater than 0 then it is decremented until it reaches 0; the waypoint is then is deleted.
 
-	Waypoint(TileIndex tile = 0);
+	Waypoint(TileIndex tile = INVALID_TILE);
 	~Waypoint();
 
-	inline bool IsValid() const { return this->xy != 0; }
+	inline bool IsValid() const { return this->xy != INVALID_TILE; }
 };
 
 static inline bool IsValidWaypointID(WaypointID index)