Codechange: Use EnumBitSet for TownFlags. (#14651)

src/newgrf_town.cpp

@@ -63,7 +63,7 @@ static uint16_t TownHistoryHelper(const Town *t, CargoLabel label, uint period,
 		case 0x82: return ClampTo<uint16_t>(this->t->cache.population);
 		case 0x83: return GB(ClampTo<uint16_t>(this->t->cache.population), 8, 8);
 		case 0x8A: return this->t->grow_counter / Ticks::TOWN_GROWTH_TICKS;
-		case 0x92: return this->t->flags;  // In original game, 0x92 and 0x93 are really one word. Since flags is a byte, this is to adjust
+		case 0x92: return this->t->flags.base(); // In original game, 0x92 and 0x93 are one word.
 		case 0x93: return 0;
 		case 0x94: return ClampTo<uint16_t>(this->t->cache.squared_town_zone_radius[to_underlying(HouseZone::TownEdge)]);
 		case 0x95: return GB(ClampTo<uint16_t>(this->t->cache.squared_town_zone_radius[to_underlying(HouseZone::TownEdge)]), 8, 8);

src/saveload/afterload.cpp

@@ -3120,7 +3120,7 @@ bool AfterLoadGame()
 		/* Convert towns growth_rate and grow_counter to ticks */
 		for (Town *t : Town::Iterate()) {
 			/* 0x8000 = TOWN_GROWTH_RATE_CUSTOM previously */
-			if (t->growth_rate & 0x8000) SetBit(t->flags, TOWN_CUSTOM_GROWTH);
+			if (t->growth_rate & 0x8000) t->flags.Set(TownFlag::CustomGrowth);
 			if (t->growth_rate != TOWN_GROWTH_RATE_NONE) {
 				t->growth_rate = TownTicksToGameTicks(t->growth_rate & ~0x8000);
 			}

src/town.h

@@ -37,6 +37,16 @@ static const uint16_t MAX_TOWN_GROWTH_TICKS = 930; ///< Max amount of original t
 typedef Pool<Town, TownID, 64> TownPool;
 extern TownPool _town_pool;
 
+/** Flags controlling various town behaviours. */
+enum class TownFlag : uint8_t {
+	IsGrowing = 0, ///< Conditions for town growth are met. Grow according to Town::growth_rate.
+	HasChurch = 1, ///< There can be only one church by town.
+	HasStadium = 2, ///< There can be only one stadium by town.
+	CustomGrowth = 3, ///< Growth rate is controlled by GS.
+};
+
+using TownFlags = EnumBitSet<TownFlag, uint8_t>;
+
 /** Data structure with cached data of towns. */
 struct TownCache {
 	uint32_t num_houses = 0; ///< Amount of houses
@@ -62,7 +72,7 @@ struct Town : TownPool::PoolItem<&_town_pool> {
 	std::string name{}; ///< Custom town name. If empty, the town was not renamed and uses the generated name.
 	mutable std::string cached_name{}; ///< NOSAVE: Cache of the resolved name of the town, if not using a custom town name
 
-	uint8_t flags = 0; ///< See #TownFlags.
+	TownFlags flags{}; ///< See #TownFlags.
 
 	uint16_t noise_reached = 0; ///< level of noise that all the airports are generating
 
@@ -224,20 +234,6 @@ enum TownDirectoryInvalidateWindowData {
 	TDIWD_FORCE_RESORT,
 };
 
-/**
- * This enum is used in conjunction with town->flags.
- * IT simply states what bit is used for.
- * It is pretty unrealistic (IMHO) to only have one church/stadium
- * per town, NO MATTER the population of it.
- * And there are 5 more bits available on flags...
- */
-enum TownFlags {
-	TOWN_IS_GROWING     = 0,   ///< Conditions for town growth are met. Grow according to Town::growth_rate.
-	TOWN_HAS_CHURCH     = 1,   ///< There can be only one church by town.
-	TOWN_HAS_STADIUM    = 2,   ///< There can be only one stadium by town.
-	TOWN_CUSTOM_GROWTH  = 3,   ///< Growth rate is controlled by GS.
-};
-
 CommandCost CheckforTownRating(DoCommandFlags flags, Town *t, TownRatingCheckType type);
 
 

src/town_cmd.cpp

@@ -666,7 +666,7 @@ static void TileLoop_Town(TileIndex tile)
 	Backup<CompanyID> cur_company(_current_company, OWNER_TOWN);
 
 	if (hs->building_flags.Any(BUILDING_HAS_1_TILE) &&
-			HasBit(t->flags, TOWN_IS_GROWING) &&
+			t->flags.Test(TownFlag::IsGrowing) &&
 			CanDeleteHouse(tile) &&
 			GetHouseAge(tile) >= hs->minimum_life &&
 			--t->time_until_rebuild == 0) {
@@ -917,7 +917,7 @@ static bool GrowTown(Town *t, TownExpandModes modes);
  */
 static void TownTickHandler(Town *t)
 {
-	if (HasBit(t->flags, TOWN_IS_GROWING)) {
+	if (t->flags.Test(TownFlag::IsGrowing)) {
 		TownExpandModes modes{TownExpandMode::Buildings};
 		if (_settings_game.economy.allow_town_roads) modes.Set(TownExpandMode::Roads);
 		int i = (int)t->grow_counter - 1;
@@ -2046,7 +2046,7 @@ static void DoCreateTown(Town *t, TileIndex tile, uint32_t townnameparts, TownSi
 	t->cache.num_houses = 0;
 	t->time_until_rebuild = 10;
 	UpdateTownRadius(t);
-	t->flags = 0;
+	t->flags.Reset();
 	t->cache.population = 0;
 	InitializeBuildingCounts(t);
 	/* Spread growth across ticks so even if there are many
@@ -2867,15 +2867,15 @@ static bool TryBuildTownHouse(Town *t, TileIndex tile, TownExpandModes modes)
 		if (TimerGameCalendar::year < hs->min_year || TimerGameCalendar::year > hs->max_year) continue;
 
 		/* Special houses that there can be only one of. */
-		uint oneof = 0;
+		TownFlags oneof{};
 
 		if (hs->building_flags.Test(BuildingFlag::IsChurch)) {
-			SetBit(oneof, TOWN_HAS_CHURCH);
+			oneof.Set(TownFlag::HasChurch);
 		} else if (hs->building_flags.Test(BuildingFlag::IsStadium)) {
-			SetBit(oneof, TOWN_HAS_STADIUM);
+			oneof.Set(TownFlag::HasStadium);
 		}
 
-		if (t->flags & oneof) continue;
+		if (t->flags.Any(oneof)) continue;
 
 		/* Make sure there is no slope? */
 		bool noslope = hs->building_flags.Test(BuildingFlag::NotSloped);
@@ -2899,7 +2899,7 @@ static bool TryBuildTownHouse(Town *t, TileIndex tile, TownExpandModes modes)
 		}
 
 		/* Special houses that there can be only one of. */
-		t->flags |= oneof;
+		t->flags.Set(oneof);
 
 		BuildTownHouse(t, tile, hs, house, random_bits, false, hs->extra_flags.Test(HouseExtraFlag::BuildingIsProtected));
 
@@ -3034,9 +3034,9 @@ void ClearTownHouse(Town *t, TileIndex tile)
 
 	/* Clear flags for houses that only may exist once/town. */
 	if (hs->building_flags.Test(BuildingFlag::IsChurch)) {
-		ClrBit(t->flags, TOWN_HAS_CHURCH);
+		t->flags.Reset(TownFlag::HasChurch);
 	} else if (hs->building_flags.Test(BuildingFlag::IsStadium)) {
-		ClrBit(t->flags, TOWN_HAS_STADIUM);
+		t->flags.Reset(TownFlag::HasStadium);
 	}
 
 	/* Do the actual clearing of tiles */
@@ -3168,7 +3168,7 @@ CommandCost CmdTownGrowthRate(DoCommandFlags flags, TownID town_id, uint16_t gro
 	if (flags.Test(DoCommandFlag::Execute)) {
 		if (growth_rate == 0) {
 			/* Just clear the flag, UpdateTownGrowth will determine a proper growth rate */
-			ClrBit(t->flags, TOWN_CUSTOM_GROWTH);
+			t->flags.Reset(TownFlag::CustomGrowth);
 		} else {
 			uint old_rate = t->growth_rate;
 			if (t->grow_counter >= old_rate) {
@@ -3179,7 +3179,7 @@ CommandCost CmdTownGrowthRate(DoCommandFlags flags, TownID town_id, uint16_t gro
 				t->grow_counter = t->grow_counter * growth_rate / old_rate;
 			}
 			t->growth_rate = growth_rate;
-			SetBit(t->flags, TOWN_CUSTOM_GROWTH);
+			t->flags.Set(TownFlag::CustomGrowth);
 		}
 		UpdateTownGrowth(t);
 		InvalidateWindowData(WC_TOWN_VIEW, town_id);
@@ -3829,7 +3829,7 @@ static uint GetNormalGrowthRate(Town *t)
  */
 static void UpdateTownGrowthRate(Town *t)
 {
-	if (HasBit(t->flags, TOWN_CUSTOM_GROWTH)) return;
+	if (t->flags.Test(TownFlag::CustomGrowth)) return;
 	uint old_rate = t->growth_rate;
 	t->growth_rate = GetNormalGrowthRate(t);
 	UpdateTownGrowCounter(t, old_rate);
@@ -3844,7 +3844,7 @@ static void UpdateTownGrowth(Town *t)
 {
 	UpdateTownGrowthRate(t);
 
-	ClrBit(t->flags, TOWN_IS_GROWING);
+	t->flags.Reset(TownFlag::IsGrowing);
 	SetWindowDirty(WC_TOWN_VIEW, t->index);
 
 	if (_settings_game.economy.town_growth_rate == 0 && t->fund_buildings_months == 0) return;
@@ -3866,15 +3866,15 @@ static void UpdateTownGrowth(Town *t)
 		}
 	}
 
-	if (HasBit(t->flags, TOWN_CUSTOM_GROWTH)) {
-		if (t->growth_rate != TOWN_GROWTH_RATE_NONE) SetBit(t->flags, TOWN_IS_GROWING);
+	if (t->flags.Test(TownFlag::CustomGrowth)) {
+		if (t->growth_rate != TOWN_GROWTH_RATE_NONE) t->flags.Set(TownFlag::IsGrowing);
 		SetWindowDirty(WC_TOWN_VIEW, t->index);
 		return;
 	}
 
 	if (t->fund_buildings_months == 0 && CountActiveStations(t) == 0 && !Chance16(1, 12)) return;
 
-	SetBit(t->flags, TOWN_IS_GROWING);
+	t->flags.Set(TownFlag::IsGrowing);
 	SetWindowDirty(WC_TOWN_VIEW, t->index);
 }
 

src/town_gui.cpp

@@ -453,7 +453,7 @@ public:
 			tr.top += GetCharacterHeight(FS_NORMAL);
 		}
 
-		if (HasBit(this->town->flags, TOWN_IS_GROWING)) {
+		if (this->town->flags.Test(TownFlag::IsGrowing)) {
 			DrawString(tr, GetString(this->town->fund_buildings_months == 0 ? STR_TOWN_VIEW_TOWN_GROWS_EVERY : STR_TOWN_VIEW_TOWN_GROWS_EVERY_FUNDED, RoundDivSU(this->town->growth_rate + 1, Ticks::DAY_TICKS)));
 			tr.top += GetCharacterHeight(FS_NORMAL);
 		} else {