Codechange: Replace duplicated code with TileArea::Expand() (#7467)

src/industry_cmd.cpp

@@ -156,8 +156,7 @@ Industry::~Industry()
 	}
 
 	if (GetIndustrySpec(this->type)->behaviour & INDUSTRYBEH_PLANT_FIELDS) {
-		TileArea ta(this->location.tile - TileDiffXY(min(TileX(this->location.tile), 21), min(TileY(this->location.tile), 21)), 42, 42);
-		ta.ClampToMap();
+		TileArea ta = TileArea(this->location.tile, 0, 0).Expand(21);
 
 		/* Remove the farmland and convert it to regular tiles over time. */
 		TILE_AREA_LOOP(tile_cur, ta) {
@@ -1533,6 +1532,8 @@ static bool CheckIfCanLevelIndustryPlatform(TileIndex tile, DoCommandFlag flags,
 	/* Check that all tiles in area and surrounding are clear
 	 * this determines that there are no obstructing items */
 
+	/* TileArea::Expand is not used here as we need to abort
+	 * instead of clamping if the bounds cannot expanded. */
 	TileArea ta(tile + TileDiffXY(-_settings_game.construction.industry_platform, -_settings_game.construction.industry_platform),
 			max_x + 2 + 2 * _settings_game.construction.industry_platform, max_y + 2 + 2 * _settings_game.construction.industry_platform);
 
@@ -1593,9 +1594,7 @@ static CommandCost CheckIfFarEnoughFromConflictingIndustry(TileIndex tile, int t
 	/* On a large map with many industries, it may be faster to check an area. */
 	static const int dmax = 14;
 	if (Industry::GetNumItems() > (size_t) (dmax * dmax * 2)) {
-		const int tx = TileX(tile);
-		const int ty = TileY(tile);
-		TileArea tile_area = TileArea(TileXY(max(0, tx - dmax), max(0, ty - dmax)), TileXY(min(MapMaxX(), tx + dmax), min(MapMaxY(), ty + dmax)));
+		TileArea tile_area = TileArea(tile, 1, 1).Expand(dmax);
 		TILE_AREA_LOOP(atile, tile_area) {
 			if (GetTileType(atile) == MP_INDUSTRY) {
 				const Industry *i2 = Industry::GetByTile(atile);

src/script/api/script_tilelist.cpp

@@ -66,7 +66,7 @@ ScriptTileList_IndustryAccepting::ScriptTileList_IndustryAccepting(IndustryID in
 
 	if (!_settings_game.station.modified_catchment) radius = CA_UNMODIFIED;
 
-	TileArea ta(i->location.tile - ::TileDiffXY(radius, radius), i->location.w + radius * 2, i->location.h + radius * 2);
+	TileArea ta = TileArea(i->location).Expand(radius);
 	TILE_AREA_LOOP(cur_tile, ta) {
 		if (!::IsValidTile(cur_tile)) continue;
 		/* Exclude all tiles that belong to this industry */
@@ -102,7 +102,7 @@ ScriptTileList_IndustryProducing::ScriptTileList_IndustryProducing(IndustryID in
 
 	if (!_settings_game.station.modified_catchment) radius = CA_UNMODIFIED;
 
-	TileArea ta(i->location.tile - ::TileDiffXY(radius, radius), i->location.w + radius * 2, i->location.h + radius * 2);
+	TileArea ta = TileArea(i->location).Expand(radius);
 	TILE_AREA_LOOP(cur_tile, ta) {
 		if (!::IsValidTile(cur_tile)) continue;
 		/* Exclude all tiles that belong to this industry */

src/station.cpp

@@ -449,7 +449,7 @@ void Station::RecomputeCatchment()
 		if (r == CA_NONE) continue;
 
 		/* This tile sub-loop doesn't need to test any tiles, they are simply added to the catchment set. */
-		TileArea ta2(TileXY(max<int>(TileX(tile) - r, 0), max<int>(TileY(tile) - r, 0)), TileXY(min<int>(TileX(tile) + r, MapMaxX()), min<int>(TileY(tile) + r, MapMaxY())));
+		TileArea ta2 = TileArea(tile, 1, 1).Expand(r);
 		TILE_AREA_LOOP(tile2, ta2) this->catchment_tiles.SetTile(tile2);
 	}
 

src/station_cmd.cpp

@@ -101,9 +101,7 @@ bool IsHangar(TileIndex t)
 template <class T>
 CommandCost GetStationAround(TileArea ta, StationID closest_station, CompanyID company, T **st)
 {
-	ta.tile -= TileDiffXY(1, 1);
-	ta.w    += 2;
-	ta.h    += 2;
+	ta.Expand(1);
 
 	/* check around to see if there are any stations there owned by the company */
 	TILE_AREA_LOOP(tile_cur, ta) {
@@ -495,25 +493,8 @@ static void ShowRejectOrAcceptNews(const Station *st, uint num_items, CargoID *c
 CargoArray GetProductionAroundTiles(TileIndex tile, int w, int h, int rad)
 {
 	CargoArray produced;
-
-	int x = TileX(tile);
-	int y = TileY(tile);
-
-	/* expand the region by rad tiles on each side
-	 * while making sure that we remain inside the board. */
-	int x2 = min(x + w + rad, MapSizeX());
-	int x1 = max(x - rad, 0);
-
-	int y2 = min(y + h + rad, MapSizeY());
-	int y1 = max(y - rad, 0);
-
-	assert(x1 < x2);
-	assert(y1 < y2);
-	assert(w > 0);
-	assert(h > 0);
-
 	std::set<IndustryID> industries;
-	TileArea ta(TileXY(x1, y1), TileXY(x2 - 1, y2 - 1));
+	TileArea ta = TileArea(tile, w, h).Expand(rad);
 
 	/* Loop over all tiles to get the produced cargo of
 	 * everything except industries */
@@ -553,30 +534,13 @@ CargoArray GetAcceptanceAroundTiles(TileIndex tile, int w, int h, int rad, Cargo
 	CargoArray acceptance;
 	if (always_accepted != nullptr) *always_accepted = 0;
 
-	int x = TileX(tile);
-	int y = TileY(tile);
-
-	/* expand the region by rad tiles on each side
-	 * while making sure that we remain inside the board. */
-	int x2 = min(x + w + rad, MapSizeX());
-	int y2 = min(y + h + rad, MapSizeY());
-	int x1 = max(x - rad, 0);
-	int y1 = max(y - rad, 0);
+	TileArea ta = TileArea(tile, w, h).Expand(rad);
 
-	assert(x1 < x2);
-	assert(y1 < y2);
-	assert(w > 0);
-	assert(h > 0);
-
-	for (int yc = y1; yc != y2; yc++) {
-		for (int xc = x1; xc != x2; xc++) {
-			TileIndex tile = TileXY(xc, yc);
-
-			/* Ignore industry if it has a neutral station. */
-			if (!_settings_game.station.serve_neutral_industries && IsTileType(tile, MP_INDUSTRY) && Industry::GetByTile(tile)->neutral_station != nullptr) continue;
+	TILE_AREA_LOOP(tile, ta) {
+		/* Ignore industry if it has a neutral station. */
+		if (!_settings_game.station.serve_neutral_industries && IsTileType(tile, MP_INDUSTRY) && Industry::GetByTile(tile)->neutral_station != nullptr) continue;
 
-			AddAcceptedCargo(tile, acceptance, always_accepted);
-		}
+		AddAcceptedCargo(tile, acceptance, always_accepted);
 	}
 
 	return acceptance;
@@ -3858,15 +3822,12 @@ void FindStationsAroundTiles(const TileArea &location, StationList * const stati
 	}
 
 	/* Not using, or don't have a nearby stations list, so we need to scan. */
-	uint x = TileX(location.tile);
-	uint y = TileY(location.tile);
-
 	std::set<StationID> seen_stations;
 
 	/* Scan an area around the building covering the maximum possible station
 	 * to find the possible nearby stations. */
 	uint max_c = _settings_game.station.modified_catchment ? MAX_CATCHMENT : CA_UNMODIFIED;
-	TileArea ta(TileXY(max<int>(0, x - max_c), max<int>(0, y - max_c)), TileXY(min<int>(MapMaxX(), x + location.w + max_c), min<int>(MapMaxY(), y + location.h + max_c)));
+	TileArea ta = TileArea(location).Expand(max_c);
 	TILE_AREA_LOOP(tile, ta) {
 		if (IsTileType(tile, MP_STATION)) seen_stations.insert(GetStationIndex(tile));
 	}

src/tilearea.cpp

@@ -117,6 +117,27 @@ bool OrthogonalTileArea::Contains(TileIndex tile) const
 	return IsInsideBS(tile_x, left, this->w) && IsInsideBS(tile_y, top, this->h);
 }
 
+/**
+ * Expand a tile area by rad tiles in each direction, keeping within map bounds.
+ * @param rad Number of tiles to expand
+ * @return The OrthogonalTileArea.
+ */
+OrthogonalTileArea &OrthogonalTileArea::Expand(int rad)
+{
+	int x = TileX(this->tile);
+	int y = TileY(this->tile);
+
+	int sx = max(x - rad, 0);
+	int sy = max(y - rad, 0);
+	int ex = min(x + this->w + rad, MapSizeX());
+	int ey = min(y + this->h + rad, MapSizeY());
+
+	this->tile = TileXY(sx, sy);
+	this->w    = ex - sx;
+	this->h    = ey - sy;
+	return *this;
+}
+
 /**
  * Clamp the tile area to map borders.
  */

src/tilearea_type.h

@@ -48,6 +48,8 @@ struct OrthogonalTileArea {
 
 	bool Contains(TileIndex tile) const;
 
+	OrthogonalTileArea &Expand(int rad);
+
 	void ClampToMap();
 
 	/**

src/waypoint_cmd.cpp

@@ -200,7 +200,7 @@ CommandCost CmdBuildRailWaypoint(TileIndex start_tile, DoCommandFlag flags, uint
 	}
 
 	Waypoint *wp = nullptr;
-	TileArea new_location(TileArea(start_tile, width, height));
+	TileArea new_location(start_tile, width, height);
 	CommandCost ret = FindJoiningWaypoint(est, station_to_join, adjacent, new_location, &wp);
 	if (ret.Failed()) return ret;