Codechange: Replace FOR_ALL_COMPANIES with range-based for loops

27 files changed, 87 insertions, 165 deletions

diff --git a/src/ai/ai_core.cpp b/src/ai/ai_core.cpp
index 459a3ead4..95c971af8 100644
--- a/src/ai/ai_core.cpp
+++ b/src/ai/ai_core.cpp
@@ -75,8 +75,7 @@
 	if ((AI::frame_counter & ((1 << (4 - _settings_game.difficulty.competitor_speed)) - 1)) != 0) return;
 
 	Backup<CompanyID> cur_company(_current_company, FILE_LINE);
-	const Company *c;
-	FOR_ALL_COMPANIES(c) {
+	for (const Company *c : Company::Iterate()) {
 		if (c->is_ai) {
 			PerformanceMeasurer framerate((PerformanceElement)(PFE_AI0 + c->index));
 			cur_company.Change(c->index);
@@ -154,8 +153,7 @@
 	/* It might happen there are no companies .. than we have nothing to loop */
 	if (Company::GetPoolSize() == 0) return;
 
-	const Company *c;
-	FOR_ALL_COMPANIES(c) {
+	for (const Company *c : Company::Iterate()) {
 		if (c->is_ai) AI::Stop(c->index);
 	}
 }
diff --git a/src/ai/ai_gui.cpp b/src/ai/ai_gui.cpp
index 25d34dee0..a684e4a35 100644
--- a/src/ai/ai_gui.cpp
+++ b/src/ai/ai_gui.cpp
@@ -1052,8 +1052,7 @@ struct AIDebugWindow : public Window {
 
 		ai_debug_company = INVALID_COMPANY;
 
-		const Company *c;
-		FOR_ALL_COMPANIES(c) {
+		for (const Company *c : Company::Iterate()) {
 			if (c->is_ai) {
 				ChangeToAI(c->index);
 				return;
@@ -1312,8 +1311,7 @@ struct AIDebugWindow : public Window {
 				if ((_pause_mode & PM_PAUSED_NORMAL) == PM_PAUSED_NORMAL) {
 					bool all_unpaused = !Game::IsPaused();
 					if (all_unpaused) {
-						Company *c;
-						FOR_ALL_COMPANIES(c) {
+						for (const Company *c : Company::Iterate()) {
 							if (c->is_ai && AI::IsPaused(c->index)) {
 								all_unpaused = false;
 								break;
@@ -1552,8 +1550,7 @@ void ShowAIDebugWindowIfAIError()
 	/* Network clients can't debug AIs. */
 	if (_networking && !_network_server) return;
 
-	Company *c;
-	FOR_ALL_COMPANIES(c) {
+	for (const Company *c : Company::Iterate()) {
 		if (c->is_ai && c->ai_instance->IsDead()) {
 			ShowAIDebugWindow(c->index);
 			break;
diff --git a/src/company_base.h b/src/company_base.h
index 874e6208e..095f7d9e6 100644
--- a/src/company_base.h
+++ b/src/company_base.h
@@ -168,9 +168,6 @@ struct Company : CompanyPool::PoolItem<&_company_pool>, CompanyProperties {
 	static void PostDestructor(size_t index);
 };
 
-#define FOR_ALL_COMPANIES_FROM(var, start) FOR_ALL_ITEMS_FROM(Company, company_index, var, start)
-#define FOR_ALL_COMPANIES(var) FOR_ALL_COMPANIES_FROM(var, 0)
-
 Money CalculateCompanyValue(const Company *c, bool including_loan = true);
 
 extern uint _next_competitor_start;
diff --git a/src/company_cmd.cpp b/src/company_cmd.cpp
index 1f427cf31..97be03fa9 100644
--- a/src/company_cmd.cpp
+++ b/src/company_cmd.cpp
@@ -263,8 +263,7 @@ void SubtractMoneyFromCompanyFract(CompanyID company, CommandCost cst)
 /** Update the landscaping limits per company. */
 void UpdateLandscapingLimits()
 {
-	Company *c;
-	FOR_ALL_COMPANIES(c) {
+	for (Company *c : Company::Iterate()) {
 		c->terraform_limit = min(c->terraform_limit + _settings_game.construction.terraform_per_64k_frames, (uint32)_settings_game.construction.terraform_frame_burst << 16);
 		c->clear_limit     = min(c->clear_limit     + _settings_game.construction.clear_per_64k_frames,     (uint32)_settings_game.construction.clear_frame_burst << 16);
 		c->tree_limit      = min(c->tree_limit      + _settings_game.construction.tree_per_64k_frames,      (uint32)_settings_game.construction.tree_frame_burst << 16);
@@ -360,8 +359,7 @@ static void GenerateCompanyName(Company *c)
 
 verify_name:;
 		/* No companies must have this name already */
-		Company *cc;
-		FOR_ALL_COMPANIES(cc) {
+		for (const Company *cc : Company::Iterate()) {
 			if (cc->name_1 == str && cc->name_2 == strp) goto bad_town_name;
 		}
 
@@ -447,8 +445,7 @@ static Colours GenerateCompanyColour()
 	}
 
 	/* Move the colours that look similar to each company's colour to the side */
-	Company *c;
-	FOR_ALL_COMPANIES(c) {
+	for (const Company *c : Company::Iterate()) {
 		Colours pcolour = (Colours)c->colour;
 
 		for (uint i = 0; i < COLOUR_END; i++) {
@@ -494,8 +491,7 @@ restart:;
 		GetString(buffer, STR_PRESIDENT_NAME, lastof(buffer));
 		if (Utf8StringLength(buffer) >= MAX_LENGTH_PRESIDENT_NAME_CHARS) continue;
 
-		Company *cc;
-		FOR_ALL_COMPANIES(cc) {
+		for (const Company *cc : Company::Iterate()) {
 			if (c != cc) {
 				/* Reserve extra space so even overlength president names can be compared. */
 				char buffer2[(MAX_LENGTH_PRESIDENT_NAME_CHARS + 1) * MAX_CHAR_LENGTH];
@@ -598,11 +594,9 @@ static bool MaybeStartNewCompany()
 {
 	if (_networking && Company::GetNumItems() >= _settings_client.network.max_companies) return false;
 
-	Company *c;
-
 	/* count number of competitors */
 	uint n = 0;
-	FOR_ALL_COMPANIES(c) {
+	for (const Company *c : Company::Iterate()) {
 		if (c->is_ai) n++;
 	}
 
@@ -671,11 +665,11 @@ static void HandleBankruptcyTakeover(Company *c)
 	/* Did we ask everyone for bankruptcy? If so, bail out. */
 	if (c->bankrupt_asked == MAX_UVALUE(CompanyMask)) return;
 
-	Company *c2, *best = nullptr;
+	Company *best = nullptr;
 	int32 best_performance = -1;
 
 	/* Ask the company with the highest performance history first */
-	FOR_ALL_COMPANIES(c2) {
+	for (Company *c2 : Company::Iterate()) {
 		if (c2->bankrupt_asked == 0 && // Don't ask companies going bankrupt themselves
 				!HasBit(c->bankrupt_asked, c2->index) &&
 				best_performance < c2->old_economy[1].performance_history &&
@@ -737,10 +731,8 @@ void OnTick_Companies()
  */
 void CompaniesYearlyLoop()
 {
-	Company *c;
-
 	/* Copy statistics */
-	FOR_ALL_COMPANIES(c) {
+	for (Company *c : Company::Iterate()) {
 		memmove(&c->yearly_expenses[1], &c->yearly_expenses[0], sizeof(c->yearly_expenses) - sizeof(c->yearly_expenses[0]));
 		memset(&c->yearly_expenses[0], 0, sizeof(c->yearly_expenses[0]));
 		SetWindowDirty(WC_FINANCES, c->index);
@@ -748,7 +740,7 @@ void CompaniesYearlyLoop()
 
 	if (_settings_client.gui.show_finances && _local_company != COMPANY_SPECTATOR) {
 		ShowCompanyFinances(_local_company);
-		c = Company::Get(_local_company);
+		Company *c = Company::Get(_local_company);
 		if (c->num_valid_stat_ent > 5 && c->old_economy[0].performance_history < c->old_economy[4].performance_history) {
 			if (_settings_client.sound.new_year) SndPlayFx(SND_01_BAD_YEAR);
 		} else {
@@ -971,8 +963,7 @@ CommandCost CmdSetCompanyColour(TileIndex tile, DoCommandFlag flags, uint32 p1,
 
 	/* Ensure no two companies have the same primary colour */
 	if (scheme == LS_DEFAULT && !second) {
-		const Company *cc;
-		FOR_ALL_COMPANIES(cc) {
+		for (const Company *cc : Company::Iterate()) {
 			if (cc != c && cc->colour == colour) return CMD_ERROR;
 		}
 	}
@@ -1053,9 +1044,7 @@ CommandCost CmdSetCompanyColour(TileIndex tile, DoCommandFlag flags, uint32 p1,
  */
 static bool IsUniqueCompanyName(const char *name)
 {
-	const Company *c;
-
-	FOR_ALL_COMPANIES(c) {
+	for (const Company *c : Company::Iterate()) {
 		if (c->name != nullptr && strcmp(c->name, name) == 0) return false;
 	}
 
@@ -1098,9 +1087,7 @@ CommandCost CmdRenameCompany(TileIndex tile, DoCommandFlag flags, uint32 p1, uin
  */
 static bool IsUniquePresidentName(const char *name)
 {
-	const Company *c;
-
-	FOR_ALL_COMPANIES(c) {
+	for (const Company *c : Company::Iterate()) {
 		if (c->president_name != nullptr && strcmp(c->president_name, name) == 0) return false;
 	}
 
diff --git a/src/company_gui.cpp b/src/company_gui.cpp
index 533a26a2d..c09dab139 100644
--- a/src/company_gui.cpp
+++ b/src/company_gui.cpp
@@ -574,7 +574,7 @@ private:
 
 		/* Disallow other company colours for the primary colour */
 		if (this->livery_class < LC_GROUP_RAIL && HasBit(this->sel, LS_DEFAULT) && primary) {
-			FOR_ALL_COMPANIES(c) {
+			for (const Company *c : Company::Iterate()) {
 				if (c->index != _local_company) SetBit(used_colours, c->colour);
 			}
 		}
@@ -2396,9 +2396,7 @@ struct CompanyWindow : Window
 				break;
 
 			case WID_C_DESC_OWNERS: {
-				const Company *c2;
-
-				FOR_ALL_COMPANIES(c2) {
+				for (const Company *c2 : Company::Iterate()) {
 					SetDParamMaxValue(0, 75);
 					SetDParam(1, c2->index);
 
@@ -2500,10 +2498,9 @@ struct CompanyWindow : Window
 			}
 
 			case WID_C_DESC_OWNERS: {
-				const Company *c2;
 				uint y = r.top;
 
-				FOR_ALL_COMPANIES(c2) {
+				for (const Company *c2 : Company::Iterate()) {
 					uint amt = GetAmountOwnedBy(c, c2->index);
 					if (amt != 0) {
 						SetDParam(0, amt * 25);
diff --git a/src/console_cmds.cpp b/src/console_cmds.cpp
index a1a155a82..f4d0626a5 100644
--- a/src/console_cmds.cpp
+++ b/src/console_cmds.cpp
@@ -1142,9 +1142,8 @@ DEF_CONSOLE_CMD(ConStartAI)
 	}
 
 	int n = 0;
-	Company *c;
 	/* Find the next free slot */
-	FOR_ALL_COMPANIES(c) {
+	for (const Company *c : Company::Iterate()) {
 		if (c->index != n) break;
 		n++;
 	}
@@ -1535,8 +1534,7 @@ DEF_CONSOLE_CMD(ConCompanies)
 		return true;
 	}
 
-	Company *c;
-	FOR_ALL_COMPANIES(c) {
+	for (const Company *c : Company::Iterate()) {
 		/* Grab the company name */
 		char company_name[512];
 		SetDParam(0, c->index);
diff --git a/src/crashlog.cpp b/src/crashlog.cpp
index a018c40a3..c7cf48154 100644
--- a/src/crashlog.cpp
+++ b/src/crashlog.cpp
@@ -193,8 +193,7 @@ char *CrashLog::LogConfiguration(char *buffer, const char *last) const
 	);
 
 	buffer += seprintf(buffer, last, "AI Configuration (local: %i) (current: %i):\n", (int)_local_company, (int)_current_company);
-	const Company *c;
-	FOR_ALL_COMPANIES(c) {
+	for (const Company *c : Company::Iterate()) {
 		if (c->ai_info == nullptr) {
 			buffer += seprintf(buffer, last, " %2i: Human\n", (int)c->index);
 		} else {
diff --git a/src/economy.cpp b/src/economy.cpp
index a5145d756..f115cf9c8 100644
--- a/src/economy.cpp
+++ b/src/economy.cpp
@@ -297,8 +297,7 @@ void ChangeOwnershipOfCompanyItems(Owner old_owner, Owner new_owner)
 		 * There are no spectators in single player, so we must pick some other company. */
 		assert(!_networking);
 		Backup<CompanyID> cur_company2(_current_company, FILE_LINE);
-		Company *c;
-		FOR_ALL_COMPANIES(c) {
+		for (const Company *c : Company::Iterate()) {
 			if (c->index != old_owner) {
 				SetLocalCompany(c->index);
 				break;
@@ -313,11 +312,10 @@ void ChangeOwnershipOfCompanyItems(Owner old_owner, Owner new_owner)
 	assert(old_owner != new_owner);
 
 	{
-		Company *c;
 		uint i;
 
 		/* See if the old_owner had shares in other companies */
-		FOR_ALL_COMPANIES(c) {
+		for (const Company *c : Company::Iterate()) {
 			for (i = 0; i < 4; i++) {
 				if (c->share_owners[i] == old_owner) {
 					/* Sell his shares */
@@ -331,7 +329,7 @@ void ChangeOwnershipOfCompanyItems(Owner old_owner, Owner new_owner)
 
 		/* Sell all the shares that people have on this company */
 		Backup<CompanyID> cur_company2(_current_company, FILE_LINE);
-		c = Company::Get(old_owner);
+		const Company *c = Company::Get(old_owner);
 		for (i = 0; i < 4; i++) {
 			cur_company2.Change(c->share_owners[i]);
 			if (_current_company != INVALID_OWNER) {
@@ -658,8 +656,7 @@ static void CompanyCheckBankrupt(Company *c)
 static void CompaniesGenStatistics()
 {
 	/* Check for bankruptcy each month */
-	Company *c;
-	FOR_ALL_COMPANIES(c) {
+	for (Company *c : Company::Iterate()) {
 		CompanyCheckBankrupt(c);
 	}
 
@@ -674,7 +671,7 @@ static void CompaniesGenStatistics()
 		}
 	} else {
 		/* Improved monthly infrastructure costs. */
-		FOR_ALL_COMPANIES(c) {
+		for (const Company *c : Company::Iterate()) {
 			cur_company.Change(c->index);
 
 			CommandCost cost(EXPENSES_PROPERTY);
@@ -700,7 +697,7 @@ static void CompaniesGenStatistics()
 	/* Only run the economic statics and update company stats every 3rd month (1st of quarter). */
 	if (!HasBit(1 << 0 | 1 << 3 | 1 << 6 | 1 << 9, _cur_month)) return;
 
-	FOR_ALL_COMPANIES(c) {
+	for (Company *c : Company::Iterate()) {
 		/* Drop the oldest history off the end */
 		std::copy_backward(c->old_economy, c->old_economy + MAX_HISTORY_QUARTERS - 1, c->old_economy + MAX_HISTORY_QUARTERS);
 		c->old_economy[0] = c->cur_economy;
@@ -833,10 +830,8 @@ void RecomputePrices()
 /** Let all companies pay the monthly interest on their loan. */
 static void CompaniesPayInterest()
 {
-	const Company *c;
-
 	Backup<CompanyID> cur_company(_current_company, FILE_LINE);
-	FOR_ALL_COMPANIES(c) {
+	for (const Company *c : Company::Iterate()) {
 		cur_company.Change(c->index);
 
 		/* Over a year the paid interest should be "loan * interest percentage",
diff --git a/src/elrail.cpp b/src/elrail.cpp
index db5a89be5..b169479da 100644
--- a/src/elrail.cpp
+++ b/src/elrail.cpp
@@ -591,7 +591,6 @@ void DrawRailCatenary(const TileInfo *ti)
 
 bool SettingsDisableElrail(int32 p1)
 {
-	Company *c;
 	Train *t;
 	bool disable = (p1 != 0);
 
@@ -632,7 +631,7 @@ bool SettingsDisableElrail(int32 p1)
 		}
 	}
 
-	FOR_ALL_COMPANIES(c) c->avail_railtypes = GetCompanyRailtypes(c->index);
+	for (Company *c : Company::Iterate()) c->avail_railtypes = GetCompanyRailtypes(c->index);
 
 	/* This resets the _last_built_railtype, which will be invalid for electric
 	 * rails. It may have unintended consequences if that function is ever
diff --git a/src/engine.cpp b/src/engine.cpp
index 3027ee387..4baf906e5 100644
--- a/src/engine.cpp
+++ b/src/engine.cpp
@@ -703,8 +703,7 @@ void StartupEngines()
 	}
 
 	/* Update the bitmasks for the vehicle lists */
-	Company *c;
-	FOR_ALL_COMPANIES(c) {
+	for (Company *c : Company::Iterate()) {
 		c->avail_railtypes = GetCompanyRailtypes(c->index);
 		c->avail_roadtypes = GetCompanyRoadTypes(c->index);
 	}
@@ -763,8 +762,7 @@ static CompanyID GetPreviewCompany(Engine *e)
 	CargoTypes cargomask = e->type != VEH_TRAIN ? GetUnionOfArticulatedRefitMasks(e->index, true) : ALL_CARGOTYPES;
 
 	int32 best_hist = -1;
-	const Company *c;
-	FOR_ALL_COMPANIES(c) {
+	for (const Company *c : Company::Iterate()) {
 		if (c->block_preview == 0 && !HasBit(e->preview_asked, c->index) &&
 				c->old_economy[0].performance_history > best_hist) {
 
@@ -806,8 +804,7 @@ static bool IsVehicleTypeDisabled(VehicleType type, bool ai)
 /** Daily check to offer an exclusive engine preview to the companies. */
 void EnginesDailyLoop()
 {
-	Company *c;
-	FOR_ALL_COMPANIES(c) {
+	for (Company *c : Company::Iterate()) {
 		c->avail_railtypes = AddDateIntroducedRailTypes(c->avail_railtypes, _date);
 		c->avail_roadtypes = AddDateIntroducedRoadTypes(c->avail_roadtypes, _date);
 	}
@@ -908,13 +905,12 @@ CommandCost CmdWantEnginePreview(TileIndex tile, DoCommandFlag flags, uint32 p1,
 static void NewVehicleAvailable(Engine *e)
 {
 	Vehicle *v;
-	Company *c;
 	EngineID index = e->index;
 
 	/* In case the company didn't build the vehicle during the intro period,
 	 * prevent that company from getting future intro periods for a while. */
 	if (e->flags & ENGINE_EXCLUSIVE_PREVIEW) {
-		FOR_ALL_COMPANIES(c) {
+		for (Company *c : Company::Iterate()) {
 			uint block_preview = c->block_preview;
 
 			if (!HasBit(e->company_avail, c->index)) continue;
@@ -948,11 +944,11 @@ static void NewVehicleAvailable(Engine *e)
 		/* maybe make another rail type available */
 		RailType railtype = e->u.rail.railtype;
 		assert(railtype < RAILTYPE_END);
-		FOR_ALL_COMPANIES(c) c->avail_railtypes = AddDateIntroducedRailTypes(c->avail_railtypes | GetRailTypeInfo(e->u.rail.railtype)->introduces_railtypes, _date);
+		for (Company *c : Company::Iterate()) c->avail_railtypes = AddDateIntroducedRailTypes(c->avail_railtypes | GetRailTypeInfo(e->u.rail.railtype)->introduces_railtypes, _date);
 	} else if (e->type == VEH_ROAD) {
 		/* maybe make another road type available */
 		assert(e->u.road.roadtype < ROADTYPE_END);
-		FOR_ALL_COMPANIES(c) c->avail_roadtypes = AddDateIntroducedRoadTypes(c->avail_roadtypes | GetRoadTypeInfo(e->u.road.roadtype)->introduces_roadtypes, _date);
+		for (Company* c : Company::Iterate()) c->avail_roadtypes = AddDateIntroducedRoadTypes(c->avail_roadtypes | GetRoadTypeInfo(e->u.road.roadtype)->introduces_roadtypes, _date);
 	}
 
 	/* Only broadcast event if AIs are able to build this vehicle type. */
diff --git a/src/graph_gui.cpp b/src/graph_gui.cpp
index 02b898a1d..d454d8a9b 100644
--- a/src/graph_gui.cpp
+++ b/src/graph_gui.cpp
@@ -567,8 +567,7 @@ public:
 		}
 
 		byte nums = 0;
-		const Company *c;
-		FOR_ALL_COMPANIES(c) {
+		for (const Company *c : Company::Iterate()) {
 			nums = min(this->num_vert_lines, max(nums, c->num_valid_stat_ent));
 		}
 
@@ -592,7 +591,7 @@ public:
 
 		int numd = 0;
 		for (CompanyID k = COMPANY_FIRST; k < MAX_COMPANIES; k++) {
-			c = Company::GetIfValid(k);
+			const Company *c = Company::GetIfValid(k);
 			if (c != nullptr) {
 				this->colours[numd] = _colour_gradient[c->colour][6];
 				for (int j = this->num_on_x_axis, i = 0; --j >= 0;) {
@@ -1136,8 +1135,7 @@ private:
 
 		this->companies.clear();
 
-		const Company *c;
-		FOR_ALL_COMPANIES(c) {
+		for (const Company *c : Company::Iterate()) {
 			this->companies.push_back(c);
 		}
 
@@ -1219,8 +1217,7 @@ public:
 		this->icon_width = d.width + 2;
 		this->line_height = max<int>(d.height + 2, FONT_HEIGHT_NORMAL);
 
-		const Company *c;
-		FOR_ALL_COMPANIES(c) {
+		for (const Company *c : Company::Iterate()) {
 			SetDParam(0, c->index);
 			SetDParam(1, c->index);
 			SetDParam(2, _performance_titles[widest_title]);
@@ -1299,8 +1296,7 @@ struct PerformanceRatingDetailWindow : Window {
 	{
 		/* Update all company stats with the current data
 		 * (this is because _score_info is not saved to a savegame) */
-		Company *c;
-		FOR_ALL_COMPANIES(c) {
+		for (Company *c : Company::Iterate()) {
 			UpdateCompanyRatingAndValue(c, false);
 		}
 
@@ -1497,8 +1493,7 @@ struct PerformanceRatingDetailWindow : Window {
 		}
 
 		if (this->company == INVALID_COMPANY) {
-			const Company *c;
-			FOR_ALL_COMPANIES(c) {
+			for (const Company *c : Company::Iterate()) {
 				this->company = c->index;
 				break;
 			}
diff --git a/src/group_cmd.cpp b/src/group_cmd.cpp
index 9f0d2cd80..95b7070c7 100644
--- a/src/group_cmd.cpp
+++ b/src/group_cmd.cpp
@@ -101,8 +101,7 @@ void GroupStatistics::Clear()
 /* static */ void GroupStatistics::UpdateAfterLoad()
 {
 	/* Set up the engine count for all companies */
-	Company *c;
-	FOR_ALL_COMPANIES(c) {
+	for (Company *c : Company::Iterate()) {
 		for (VehicleType type = VEH_BEGIN; type < VEH_COMPANY_END; type++) {
 			c->group_all[type].Clear();
 			c->group_default[type].Clear();
@@ -123,7 +122,7 @@ void GroupStatistics::Clear()
 		if (v->IsPrimaryVehicle()) GroupStatistics::CountVehicle(v, 1);
 	}
 
-	FOR_ALL_COMPANIES(c) {
+	for (const Company *c : Company::Iterate()) {
 		GroupStatistics::UpdateAutoreplace(c->index);
 	}
 }
@@ -183,8 +182,7 @@ void GroupStatistics::Clear()
 /* static */ void GroupStatistics::UpdateProfits()
 {
 	/* Set up the engine count for all companies */
-	Company *c;
-	FOR_ALL_COMPANIES(c) {
+	for (Company *c : Company::Iterate()) {
 		for (VehicleType type = VEH_BEGIN; type < VEH_COMPANY_END; type++) {
 			c->group_all[type].ClearProfits();
 			c->group_default[type].ClearProfits();
diff --git a/src/highscore.cpp b/src/highscore.cpp
index ccdf4d79f..d8fe348fe 100644
--- a/src/highscore.cpp
+++ b/src/highscore.cpp
@@ -87,13 +87,12 @@ static bool HighScoreSorter(const Company * const &a, const Company * const &b)
  */
 int8 SaveHighScoreValueNetwork()
 {
-	const Company *c;
 	const Company *cl[MAX_COMPANIES];
 	uint count = 0;
 	int8 company = -1;
 
 	/* Sort all active companies with the highest score first */
-	FOR_ALL_COMPANIES(c) cl[count++] = c;
+	for (const Company *c : Company::Iterate()) cl[count++] = c;
 
 	std::sort(std::begin(cl), std::begin(cl) + count, HighScoreSorter);
 
diff --git a/src/network/network_admin.cpp b/src/network/network_admin.cpp
index 25481da93..037307627 100644
--- a/src/network/network_admin.cpp
+++ b/src/network/network_admin.cpp
@@ -399,8 +399,7 @@ NetworkRecvStatus ServerNetworkAdminSocketHandler::SendCompanyRemove(CompanyID c
 /** Send economic information of all companies. */
 NetworkRecvStatus ServerNetworkAdminSocketHandler::SendCompanyEconomy()
 {
-	const Company *company;
-	FOR_ALL_COMPANIES(company) {
+	for (const Company *company : Company::Iterate()) {
 		/* Get the income. */
 		Money income = 0;
 		for (uint i = 0; i < lengthof(company->yearly_expenses[0]); i++) {
@@ -438,10 +437,8 @@ NetworkRecvStatus ServerNetworkAdminSocketHandler::SendCompanyStats()
 	NetworkCompanyStats company_stats[MAX_COMPANIES];
 	NetworkPopulateCompanyStats(company_stats);
 
-	const Company *company;
-
 	/* Go through all the companies. */
-	FOR_ALL_COMPANIES(company) {
+	for (const Company *company : Company::Iterate()) {
 		Packet *p = new Packet(ADMIN_PACKET_SERVER_COMPANY_STATS);
 
 		/* Send the information. */
@@ -748,13 +745,12 @@ NetworkRecvStatus ServerNetworkAdminSocketHandler::Receive_ADMIN_POLL(Packet *p)
 
 		case ADMIN_UPDATE_COMPANY_INFO:
 			/* The admin is asking for company info. */
-			const Company *company;
 			if (d1 == UINT32_MAX) {
-				FOR_ALL_COMPANIES(company) {
+				for (const Company *company : Company::Iterate()) {
 					this->SendCompanyInfo(company);
 				}
 			} else {
-				company = Company::GetIfValid(d1);
+				const Company *company = Company::GetIfValid(d1);
 				if (company != nullptr) this->SendCompanyInfo(company);
 			}
 			break;
diff --git a/src/network/network_server.cpp b/src/network/network_server.cpp
index 7505bff87..a8322ff90 100644
--- a/src/network/network_server.cpp
+++ b/src/network/network_server.cpp
@@ -380,10 +380,9 @@ NetworkRecvStatus ServerNetworkGameSocketHandler::SendCompanyInfo()
 
 	/* Now send the data */
 
-	Company *company;
 	Packet *p;
 
-	FOR_ALL_COMPANIES(company) {
+	for (const Company *company : Company::Iterate()) {
 		p = new Packet(PACKET_SERVER_COMPANY_INFO);
 
 		p->Send_uint8 (NETWORK_COMPANY_INFO_VERSION);
@@ -1619,7 +1618,6 @@ static void NetworkCheckRestartMap()
 static void NetworkAutoCleanCompanies()
 {
 	const NetworkClientInfo *ci;
-	const Company *c;
 	bool clients_in_company[MAX_COMPANIES];
 	int vehicles_in_company[MAX_COMPANIES];
 
@@ -1648,7 +1646,7 @@ static void NetworkAutoCleanCompanies()
 	}
 
 	/* Go through all the companies */
-	FOR_ALL_COMPANIES(c) {
+	for (const Company *c : Company::Iterate()) {
 		/* Skip the non-active once */
 		if (c->is_ai) continue;
 
diff --git a/src/network/network_udp.cpp b/src/network/network_udp.cpp
index ddf2e9518..90b99ec44 100644
--- a/src/network/network_udp.cpp
+++ b/src/network/network_udp.cpp
@@ -198,8 +198,7 @@ void ServerNetworkUDPSocketHandler::Receive_CLIENT_DETAIL_INFO(Packet *p, Networ
 
 		for (;;) {
 			int free = SEND_MTU - packet.size;
-			Company *company;
-			FOR_ALL_COMPANIES(company) {
+			for (const Company *company : Company::Iterate()) {
 				char company_name[NETWORK_COMPANY_NAME_LENGTH];
 				SetDParam(0, company->index);
 				GetString(company_name, STR_COMPANY_NAME, company_name + max_cname_length - 1);
@@ -214,9 +213,8 @@ void ServerNetworkUDPSocketHandler::Receive_CLIENT_DETAIL_INFO(Packet *p, Networ
 		}
 	}
 
-	Company *company;
 	/* Go through all the companies */
-	FOR_ALL_COMPANIES(company) {
+	for (const Company *company : Company::Iterate()) {
 		/* Send the information */
 		this->SendCompanyInformation(&packet, company, &company_stats[company->index], max_cname_length);
 	}
diff --git a/src/openttd.cpp b/src/openttd.cpp
index c7c518ae4..fde01111d 100644
--- a/src/openttd.cpp
+++ b/src/openttd.cpp
@@ -1207,14 +1207,13 @@ static void CheckCaches()
 
 	/* Check company infrastructure cache. */
 	std::vector<CompanyInfrastructure> old_infrastructure;
-	Company *c;
-	FOR_ALL_COMPANIES(c) old_infrastructure.push_back(c->infrastructure);
+	for (const Company *c : Company::Iterate()) old_infrastructure.push_back(c->infrastructure);
 
 	extern void AfterLoadCompanyStats();
 	AfterLoadCompanyStats();
 
 	i = 0;
-	FOR_ALL_COMPANIES(c) {
+	for (const Company *c : Company::Iterate()) {
 		if (MemCmpT(old_infrastructure.data() + i, &c->infrastructure) != 0) {
 			DEBUG(desync, 2, "infrastructure cache mismatch: company %i", (int)c->index);
 		}
diff --git a/src/saveload/afterload.cpp b/src/saveload/afterload.cpp
index 943885473..c10904c8a 100644
--- a/src/saveload/afterload.cpp
+++ b/src/saveload/afterload.cpp
@@ -243,8 +243,7 @@ static void InitializeWindowsAndCaches()
 	UpdateAllVirtCoords();
 	ResetViewportAfterLoadGame();
 
-	Company *c;
-	FOR_ALL_COMPANIES(c) {
+	for (Company *c : Company::Iterate()) {
 		/* For each company, verify (while loading a scenario) that the inauguration date is the current year and set it
 		 * accordingly if it is not the case.  No need to set it on companies that are not been used already,
 		 * thus the MIN_YEAR (which is really nothing more than Zero, initialized value) test */
@@ -644,8 +643,7 @@ bool AfterLoadGame()
 	}
 
 	if (IsSavegameVersionBefore(SLV_84)) {
-		Company *c;
-		FOR_ALL_COMPANIES(c) {
+		for (Company *c : Company::Iterate()) {
 			c->name = CopyFromOldName(c->name_1);
 			if (c->name != nullptr) c->name_1 = STR_SV_UNNAMED;
 			c->president_name = CopyFromOldName(c->president_name_1);
@@ -678,8 +676,7 @@ bool AfterLoadGame()
 		}
 
 		/* the same applies to Company::location_of_HQ */
-		Company *c;
-		FOR_ALL_COMPANIES(c) {
+		for (Company *c : Company::Iterate()) {
 			if (c->location_of_HQ == 0 || (IsSavegameVersionBefore(SLV_4) && c->location_of_HQ == 0xFFFF)) {
 				c->location_of_HQ = INVALID_TILE;
 			}
@@ -800,8 +797,7 @@ bool AfterLoadGame()
 
 	/* Make sure there is an AI attached to an AI company */
 	{
-		Company *c;
-		FOR_ALL_COMPANIES(c) {
+		for (const Company *c : Company::Iterate()) {
 			if (c->is_ai && c->ai_instance == nullptr) AI::StartNew(c->index);
 		}
 	}
@@ -1000,8 +996,7 @@ bool AfterLoadGame()
 	/* From version 16.0, we included autorenew on engines, which are now saved, but
 	 *  of course, we do need to initialize them for older savegames. */
 	if (IsSavegameVersionBefore(SLV_16)) {
-		Company *c;
-		FOR_ALL_COMPANIES(c) {
+		for (Company *c : Company::Iterate()) {
 			c->engine_renew_list            = nullptr;
 			c->settings.engine_renew        = false;
 			c->settings.engine_renew_months = 6;
@@ -1014,7 +1009,7 @@ bool AfterLoadGame()
 		 * becomes company 0, unless we are in the scenario editor where all the
 		 * companies are 'invalid'.
 		 */
-		c = Company::GetIfValid(COMPANY_FIRST);
+		Company *c = Company::GetIfValid(COMPANY_FIRST);
 		if (!_network_dedicated && c != nullptr) {
 			c->settings = _settings_client.company;
 		}
@@ -1349,8 +1344,7 @@ bool AfterLoadGame()
 	 * replaced, shall keep their old length. In all prior versions, just default
 	 * to false */
 	if (IsSavegameVersionBefore(SLV_16, 1)) {
-		Company *c;
-		FOR_ALL_COMPANIES(c) c->settings.renew_keep_length = false;
+		for (Company *c : Company::Iterate()) c->settings.renew_keep_length = false;
 	}
 
 	if (IsSavegameVersionBefore(SLV_123)) {
@@ -1413,12 +1407,10 @@ bool AfterLoadGame()
 	YapfNotifyTrackLayoutChange(INVALID_TILE, INVALID_TRACK);
 
 	if (IsSavegameVersionBefore(SLV_34)) {
-		Company *c;
-		FOR_ALL_COMPANIES(c) ResetCompanyLivery(c);
+		for (Company *c : Company::Iterate()) ResetCompanyLivery(c);
 	}
 
-	Company *c;
-	FOR_ALL_COMPANIES(c) {
+	for (Company *c : Company::Iterate()) {
 		c->avail_railtypes = GetCompanyRailtypes(c->index);
 		c->avail_roadtypes = GetCompanyRoadTypes(c->index);
 	}
@@ -1440,7 +1432,7 @@ bool AfterLoadGame()
 		FOR_ALL_STATIONS(st)  st->build_date      += DAYS_TILL_ORIGINAL_BASE_YEAR;
 		FOR_ALL_WAYPOINTS(wp) wp->build_date      += DAYS_TILL_ORIGINAL_BASE_YEAR;
 		FOR_ALL_ENGINES(e)    e->intro_date       += DAYS_TILL_ORIGINAL_BASE_YEAR;
-		FOR_ALL_COMPANIES(c)  c->inaugurated_year += ORIGINAL_BASE_YEAR;
+		for (Company *c : Company::Iterate()) c->inaugurated_year += ORIGINAL_BASE_YEAR;
 		FOR_ALL_INDUSTRIES(i) i->last_prod_year   += ORIGINAL_BASE_YEAR;
 
 		FOR_ALL_VEHICLES(v) {
@@ -1592,7 +1584,7 @@ bool AfterLoadGame()
 		}
 	}
 
-	if (IsSavegameVersionBefore(SLV_49)) FOR_ALL_COMPANIES(c) c->face = ConvertFromOldCompanyManagerFace(c->face);
+	if (IsSavegameVersionBefore(SLV_49)) for (Company *c : Company::Iterate()) c->face = ConvertFromOldCompanyManagerFace(c->face);
 
 	if (IsSavegameVersionBefore(SLV_52)) {
 		for (TileIndex t = 0; t < map_size; t++) {
@@ -1792,7 +1784,7 @@ bool AfterLoadGame()
 		 *      *really* old revisions of OTTD; else it is already set in InitializeCompanies())
 		 * 2) shares that are owned by inactive companies or self
 		 *     (caused by cheating clients in earlier revisions) */
-		FOR_ALL_COMPANIES(c) {
+		for (Company *c : Company::Iterate()) {
 			for (uint i = 0; i < 4; i++) {
 				CompanyID company = c->share_owners[i];
 				if (company == INVALID_COMPANY) continue;
@@ -2061,8 +2053,7 @@ bool AfterLoadGame()
 		}
 
 		/* More companies ... */
-		Company *c;
-		FOR_ALL_COMPANIES(c) {
+		for (Company *c : Company::Iterate()) {
 			if (c->bankrupt_asked == 0xFF) c->bankrupt_asked = 0xFFFF;
 		}
 
@@ -2199,8 +2190,7 @@ bool AfterLoadGame()
 
 	if (IsSavegameVersionBefore(SLV_120)) {
 		extern VehicleDefaultSettings _old_vds;
-		Company *c;
-		FOR_ALL_COMPANIES(c) {
+		for (Company *c : Company::Iterate()) {
 			c->settings.vehicle = _old_vds;
 		}
 	}
@@ -2663,8 +2653,7 @@ bool AfterLoadGame()
 		}
 
 		/* Introduced terraform/clear limits. */
-		Company *c;
-		FOR_ALL_COMPANIES(c) {
+		for (Company *c : Company::Iterate()) {
 			c->terraform_limit = _settings_game.construction.terraform_frame_burst << 16;
 			c->clear_limit     = _settings_game.construction.clear_frame_burst << 16;
 		}
@@ -2923,8 +2912,7 @@ bool AfterLoadGame()
 
 	if (IsSavegameVersionBefore(SLV_175)) {
 		/* Introduced tree planting limit. */
-		Company *c;
-		FOR_ALL_COMPANIES(c) c->tree_limit = _settings_game.construction.tree_frame_burst << 16;
+		for (Company *c : Company::Iterate()) c->tree_limit = _settings_game.construction.tree_frame_burst << 16;
 	}
 
 	if (IsSavegameVersionBefore(SLV_177)) {
@@ -2933,7 +2921,7 @@ bool AfterLoadGame()
 		if (_economy.inflation_payment > MAX_INFLATION) _economy.inflation_payment = MAX_INFLATION;
 
 		/* We have to convert the quarters of bankruptcy into months of bankruptcy */
-		FOR_ALL_COMPANIES(c) {
+		for (Company *c : Company::Iterate()) {
 			c->months_of_bankruptcy = 3 * c->months_of_bankruptcy;
 		}
 	}
diff --git a/src/saveload/company_sl.cpp b/src/saveload/company_sl.cpp
index 19e2e2343..e1dc5cdc2 100644
--- a/src/saveload/company_sl.cpp
+++ b/src/saveload/company_sl.cpp
@@ -94,8 +94,7 @@ CompanyManagerFace ConvertFromOldCompanyManagerFace(uint32 face)
 void AfterLoadCompanyStats()
 {
 	/* Reset infrastructure statistics to zero. */
-	Company *c;
-	FOR_ALL_COMPANIES(c) MemSetT(&c->infrastructure, 0);
+	for (Company *c : Company::Iterate()) MemSetT(&c->infrastructure, 0);
 
 	/* Collect airport count. */
 	Station *st;
@@ -105,6 +104,7 @@ void AfterLoadCompanyStats()
 		}
 	}
 
+	Company *c;
 	for (TileIndex tile = 0; tile < MapSize(); tile++) {
 		switch (GetTileType(tile)) {
 			case MP_RAILWAY:
@@ -486,8 +486,7 @@ static void SaveLoad_PLYR(Company *c)
 
 static void Save_PLYR()
 {
-	Company *c;
-	FOR_ALL_COMPANIES(c) {
+	for (Company *c : Company::Iterate()) {
 		SlSetArrayIndex(c->index);
 		SlAutolength((AutolengthProc*)SaveLoad_PLYR, c);
 	}
@@ -534,8 +533,7 @@ static void Check_PLYR()
 
 static void Ptrs_PLYR()
 {
-	Company *c;
-	FOR_ALL_COMPANIES(c) {
+	for (Company *c : Company::Iterate()) {
 		SlObject(c, _company_settings_desc);
 	}
 }
diff --git a/src/saveload/oldloader_sl.cpp b/src/saveload/oldloader_sl.cpp
index ae7aa890c..3a3efa34d 100644
--- a/src/saveload/oldloader_sl.cpp
+++ b/src/saveload/oldloader_sl.cpp
@@ -459,8 +459,7 @@ static bool FixTTOEngines()
 
 static void FixTTOCompanies()
 {
-	Company *c;
-	FOR_ALL_COMPANIES(c) {
+	for (Company *c : Company::Iterate()) {
 		c->cur_economy.company_value = CalculateCompanyValue(c); // company value history is zeroed
 	}
 }
diff --git a/src/saveload/saveload.cpp b/src/saveload/saveload.cpp
index 639461460..d652f0d25 100644
--- a/src/saveload/saveload.cpp
+++ b/src/saveload/saveload.cpp
@@ -2816,8 +2816,7 @@ void GenerateDefaultSaveName(char *buf, const char *last)
 	 * 'Spectator' as "company" name. */
 	CompanyID cid = _local_company;
 	if (!Company::IsValidID(cid)) {
-		const Company *c;
-		FOR_ALL_COMPANIES(c) {
+		for (const Company *c : Company::Iterate()) {
 			cid = c->index;
 			break;
 		}
diff --git a/src/screenshot.cpp b/src/screenshot.cpp
index 218231cd7..60196cdf0 100644
--- a/src/screenshot.cpp
+++ b/src/screenshot.cpp
@@ -315,8 +315,7 @@ static bool MakePNGImage(const char *name, ScreenshotCallback *callb, void *user
 		p += seprintf(p, lastof(buf), " %s\n", c->filename);
 	}
 	p = strecpy(p, "\nCompanies:\n", lastof(buf));
-	const Company *c;
-	FOR_ALL_COMPANIES(c) {
+	for (const Company *c : Company::Iterate()) {
 		if (c->ai_info == nullptr) {
 			p += seprintf(p, lastof(buf), "%2i: Human\n", (int)c->index);
 		} else {
diff --git a/src/smallmap_gui.cpp b/src/smallmap_gui.cpp
index 1cc9354da..d76c4652f 100644
--- a/src/smallmap_gui.cpp
+++ b/src/smallmap_gui.cpp
@@ -333,8 +333,7 @@ void BuildOwnerLegend()
 	_legend_land_owners[1].colour = _heightmap_schemes[_settings_client.gui.smallmap_land_colour].default_colour;
 
 	int i = NUM_NO_COMPANY_ENTRIES;
-	const Company *c;
-	FOR_ALL_COMPANIES(c) {
+	for (const Company *c : Company::Iterate()) {
 		_legend_land_owners[i].colour = _colour_gradient[c->colour][5];
 		_legend_land_owners[i].company = c->index;
 		_legend_land_owners[i].show_on_map = true;
diff --git a/src/statusbar_gui.cpp b/src/statusbar_gui.cpp
index 3f4396704..322e196df 100644
--- a/src/statusbar_gui.cpp
+++ b/src/statusbar_gui.cpp
@@ -120,8 +120,7 @@ struct StatusBarWindow : Window {
 
 			case WID_S_RIGHT: {
 				int64 max_money = UINT32_MAX;
-				const Company *c;
-				FOR_ALL_COMPANIES(c) max_money = max<int64>(c->money, max_money);
+				for (const Company *c : Company::Iterate()) max_money = max<int64>(c->money, max_money);
 				SetDParam(0, 100LL * max_money);
 				d = GetStringBoundingBox(STR_COMPANY_MONEY);
 				break;
diff --git a/src/terraform_gui.cpp b/src/terraform_gui.cpp
index bdf37a978..2f65bb610 100644
--- a/src/terraform_gui.cpp
+++ b/src/terraform_gui.cpp
@@ -500,8 +500,7 @@ static void ResetLandscapeConfirmationCallback(Window *w, bool confirmed)
 		_generating_world = true;
 
 		/* Delete all companies */
-		Company *c;
-		FOR_ALL_COMPANIES(c) {
+		for (Company *c : Company::Iterate()) {
 			ChangeOwnershipOfCompanyItems(c->index, INVALID_OWNER);
 			delete c;
 		}
diff --git a/src/town_cmd.cpp b/src/town_cmd.cpp
index fbfd87492..6f907bc3c 100644
--- a/src/town_cmd.cpp
+++ b/src/town_cmd.cpp
@@ -3294,8 +3294,7 @@ static void ForAllStationsNearTown(Town *t, Func func)
 static void UpdateTownRating(Town *t)
 {
 	/* Increase company ratings if they're low */
-	const Company *c;
-	FOR_ALL_COMPANIES(c) {
+	for (const Company *c : Company::Iterate()) {
 		if (t->ratings[c->index] < RATING_GROWTH_MAXIMUM) {
 			t->ratings[c->index] = min((int)RATING_GROWTH_MAXIMUM, t->ratings[c->index] + RATING_GROWTH_UP_STEP);
 		}
@@ -3451,9 +3450,7 @@ static void UpdateTownAmounts(Town *t)
 
 static void UpdateTownUnwanted(Town *t)
 {
-	const Company *c;
-
-	FOR_ALL_COMPANIES(c) {
+	for (const Company *c : Company::Iterate()) {
 		if (t->unwanted[c->index] > 0) t->unwanted[c->index]--;
 	}
 }
diff --git a/src/town_gui.cpp b/src/town_gui.cpp
index a0f04314d..2f5a72a36 100644
--- a/src/town_gui.cpp
+++ b/src/town_gui.cpp
@@ -149,8 +149,7 @@ public:
 		uint exclusive_left = rtl ? right - icon_width - exclusive_width - 2 : left + icon_width + 2;
 
 		/* Draw list of companies */
-		const Company *c;
-		FOR_ALL_COMPANIES(c) {
+		for (const Company *c : Company::Iterate()) {
 			if ((HasBit(this->town->have_ratings, c->index) || this->town->exclusivity == c->index)) {
 				DrawCompanyIcon(c->index, icon_left, y + icon_y_offset);