Codechange: Refactor FindStationsAroundTiles to avoid code duplication

src/industry_cmd.cpp

@@ -1697,20 +1697,10 @@ static void PopulateStationsNearby(Industry *ind)
 		return;
 	}
 
-	/* Get our list of nearby stations. */
-	FindStationsAroundTiles(ind->location, &ind->stations_near, false);
-
-	/* Test if industry can accept cargo */
-	uint cargo_index;
-	for (cargo_index = 0; cargo_index < lengthof(ind->accepts_cargo); cargo_index++) {
-		if (ind->accepts_cargo[cargo_index] != CT_INVALID) break;
-	}
-	if (cargo_index >= lengthof(ind->accepts_cargo)) return;
-
-	/* Cargo is accepted, add industry to nearby stations nearby industry list. */
-	for (Station *st : ind->stations_near) {
-		st->industries_near.insert(ind);
-	}
+	ForAllStationsAroundTiles(ind->location, [ind](Station *st) {
+		ind->stations_near.insert(st);
+		st->AddIndustryToDeliver(ind);
+	});
 }
 
 /**

src/station.cpp

@@ -359,12 +359,11 @@ Rect Station::GetCatchmentRect() const
 /**
  * Add nearby industry to station's industries_near list if it accepts cargo.
  * @param ind Industry
- * @param st Station
  */
-static void AddIndustryToDeliver(Industry *ind, Station *st)
+void Station::AddIndustryToDeliver(Industry *ind)
 {
 	/* Don't check further if this industry is already in the list */
-	if (st->industries_near.find(ind) != st->industries_near.end()) return;
+	if (this->industries_near.find(ind) != this->industries_near.end()) return;
 
 	/* Include only industries that can accept cargo */
 	uint cargo_index;
@@ -373,7 +372,7 @@ static void AddIndustryToDeliver(Industry *ind, Station *st)
 	}
 	if (cargo_index >= lengthof(ind->accepts_cargo)) return;
 
-	st->industries_near.insert(ind);
+	this->industries_near.insert(ind);
 }
 
 /**
@@ -464,7 +463,7 @@ void Station::RecomputeCatchment()
 			i->stations_near.insert(this);
 
 			/* Add if we can deliver to this industry as well */
-			AddIndustryToDeliver(i, this);
+			this->AddIndustryToDeliver(i);
 		}
 	}
 }

src/station_base.h

@@ -503,6 +503,7 @@ struct Station FINAL : SpecializedStation<Station, false> {
 	uint GetCatchmentRadius() const;
 	Rect GetCatchmentRect() const;
 	bool CatchmentCoversTown(TownID t) const;
+	void AddIndustryToDeliver(Industry *ind);
 	void RemoveFromAllNearbyLists();
 
 	inline bool TileIsInCatchment(TileIndex tile) const
@@ -557,4 +558,39 @@ class AirportTileIterator : public OrthogonalTileIterator {
 
 void RebuildStationKdtree();
 
+/**
+ * Call a function on all stations that have any part of the requested area within their catchment.
+ * @param area The tile area to check
+ */
+template<typename Func>
+void ForAllStationsAroundTiles(const TileArea &ta, Func func)
+{
+	/* Not using, or don't have a nearby stations list, so we need to scan. */
+	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_ext = TileArea(ta).Expand(max_c);
+	TILE_AREA_LOOP(tile, ta_ext) {
+		if (IsTileType(tile, MP_STATION)) seen_stations.insert(GetStationIndex(tile));
+	}
+
+	for (StationID stationid : seen_stations) {
+		Station *st = Station::GetIfValid(stationid);
+		if (st == nullptr) continue; /* Waypoint */
+
+		/* Check if station is attached to an industry */
+		if (!_settings_game.station.serve_neutral_industries && st->industry != nullptr) continue;
+
+		/* Test if the tile is within the station's catchment */
+		TILE_AREA_LOOP(tile, ta) {
+			if (st->TileIsInCatchment(tile)) {
+				func(st);
+				break;
+			}
+		}
+	}
+}
+
 #endif /* STATION_BASE_H */

src/station_cmd.cpp

@@ -36,6 +36,7 @@
 #include "animated_tile_func.h"
 #include "elrail_func.h"
 #include "station_base.h"
+#include "station_func.h"
 #include "station_kdtree.h"
 #include "roadstop_base.h"
 #include "newgrf_railtype.h"
@@ -3965,70 +3966,28 @@ static void AddNearbyStationsByCatchment(TileIndex tile, StationList *stations,
 	}
 }
 
-/**
- * Find all stations around a rectangular producer (industry, house, headquarter, ...)
- *
- * @param location The location/area of the producer
- * @param[out] stations The list to store the stations in
- * @param use_nearby Use nearby station list of industry/town associated with location.tile
- */
-void FindStationsAroundTiles(const TileArea &location, StationList * const stations, bool use_nearby)
-{
-	if (use_nearby) {
-		/* Industries and towns maintain a list of nearby stations */
-		if (IsTileType(location.tile, MP_INDUSTRY)) {
-			/* Industry nearby stations are already filtered by catchment. */
-			*stations = Industry::GetByTile(location.tile)->stations_near;
-			return;
-		} else if (IsTileType(location.tile, MP_HOUSE)) {
-			/* Town nearby stations need to be filtered per tile. */
-			assert(location.w == 1 && location.h == 1);
-			AddNearbyStationsByCatchment(location.tile, stations, Town::GetByTile(location.tile)->stations_near);
-			return;
-		}
-	}
-
-	/* Not using, or don't have a nearby stations list, so we need to scan. */
-	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 = TileArea(location).Expand(max_c);
-	TILE_AREA_LOOP(tile, ta) {
-		if (IsTileType(tile, MP_STATION)) seen_stations.insert(GetStationIndex(tile));
-	}
-
-	for (StationID stationid : seen_stations) {
-		Station *st = Station::GetIfValid(stationid);
-		if (st == nullptr) continue; /* Waypoint */
-
-		/* Check if station is attached to an industry */
-		if (!_settings_game.station.serve_neutral_industries && st->industry != nullptr) continue;
-
-		/* Test if the tile is within the station's catchment */
-		TILE_AREA_LOOP(tile, location) {
-			if (st->TileIsInCatchment(tile)) {
-				stations->insert(st);
-				break;
-			}
-		}
-	}
-}
-
 /**
  * Run a tile loop to find stations around a tile, on demand. Cache the result for further requests
  * @return pointer to a StationList containing all stations found
  */
 const StationList *StationFinder::GetStations()
 {
 	if (this->tile != INVALID_TILE) {
-		FindStationsAroundTiles(*this, &this->stations);
+		if (IsTileType(this->tile, MP_HOUSE)) {
+			/* Town nearby stations need to be filtered per tile. */
+			assert(this->w == 1 && this->h == 1);
+			AddNearbyStationsByCatchment(this->tile, &this->stations, Town::GetByTile(this->tile)->stations_near);
+		} else {
+			ForAllStationsAroundTiles(*this, [this](Station *st) {
+				this->stations.insert(st);
+			});
+		}
 		this->tile = INVALID_TILE;
 	}
 	return &this->stations;
 }
 
+
 static bool CanMoveGoodsToStation(const Station *st, CargoID type)
 {
 	/* Is the station reserved exclusively for somebody else? */

src/station_func.h

@@ -22,8 +22,6 @@
 
 void ModifyStationRatingAround(TileIndex tile, Owner owner, int amount, uint radius);
 
-void FindStationsAroundTiles(const TileArea &location, StationList *stations, bool use_nearby = true);
-
 void ShowStationViewWindow(StationID station);
 void UpdateAllStationVirtCoords();
 void ClearAllStationCachedNames();

src/station_gui.cpp

@@ -102,7 +102,7 @@ static void FindStationsAroundSelection()
 
 	Station *adjacent = nullptr;
 
-	/* Direct loop instead of FindStationsAroundTiles as we are not interested in catchment area */
+	/* Direct loop instead of ForAllStationsAroundTiles as we are not interested in catchment area */
 	TILE_AREA_LOOP(tile, ta) {
 		if (IsTileType(tile, MP_STATION) && GetTileOwner(tile) == _local_company) {
 			Station *st = Station::GetByTile(tile);

src/town_cmd.cpp

@@ -2249,7 +2249,11 @@ static void MakeTownHouse(TileIndex t, Town *town, byte counter, byte stage, Hou
 	if (size & BUILDING_2_TILES_X)   ClearMakeHouseTile(t + TileDiffXY(1, 0), town, counter, stage, ++type, random_bits);
 	if (size & BUILDING_HAS_4_TILES) ClearMakeHouseTile(t + TileDiffXY(1, 1), town, counter, stage, ++type, random_bits);
 
-	if (!_generating_world) FindStationsAroundTiles(TileArea(t, (size & BUILDING_2_TILES_X) ? 2 : 1, (size & BUILDING_2_TILES_Y) ? 2 : 1), &town->stations_near, false);
+	if (!_generating_world) {
+		ForAllStationsAroundTiles(TileArea(t, (size & BUILDING_2_TILES_X) ? 2 : 1, (size & BUILDING_2_TILES_Y) ? 2 : 1), [town](Station *st) {
+			town->stations_near.insert(st);
+		});
+	}
 }