Codechange: Avoid copying function parameters by using const references

src/ai/ai_gui.cpp

@@ -589,7 +589,7 @@ struct AISettingsWindow : public Window {
 	}
 
 private:
-	bool IsEditableItem(const ScriptConfigItem config_item) const
+	bool IsEditableItem(const ScriptConfigItem &config_item) const
 	{
 		return _game_mode == GM_MENU || ((this->slot != OWNER_DEITY) && !Company::IsValidID(this->slot)) || (config_item.flags & SCRIPTCONFIG_INGAME) != 0;
 	}

src/company_cmd.cpp

@@ -208,7 +208,7 @@ bool CheckCompanyHasMoney(CommandCost &cost)
  * @param c Company to pay the bill.
  * @param cost Money to pay.
  */
-static void SubtractMoneyFromAnyCompany(Company *c, CommandCost cost)
+static void SubtractMoneyFromAnyCompany(Company *c, const CommandCost &cost)
 {
 	if (cost.GetCost() == 0) return;
 	assert(cost.GetExpensesType() != INVALID_EXPENSES);
@@ -237,7 +237,7 @@ static void SubtractMoneyFromAnyCompany(Company *c, CommandCost cost)
  * Subtract money from the #_current_company, if the company is valid.
  * @param cost Money to pay.
  */
-void SubtractMoneyFromCompany(CommandCost cost)
+void SubtractMoneyFromCompany(const CommandCost &cost)
 {
 	Company *c = Company::GetIfValid(_current_company);
 	if (c != nullptr) SubtractMoneyFromAnyCompany(c, cost);
@@ -248,7 +248,7 @@ void SubtractMoneyFromCompany(CommandCost cost)
  * @param company Company paying the bill.
  * @param cst     Cost of a command.
  */
-void SubtractMoneyFromCompanyFract(CompanyID company, CommandCost cst)
+void SubtractMoneyFromCompanyFract(CompanyID company, const CommandCost &cst)
 {
 	Company *c = Company::Get(company);
 	byte m = c->money_fraction;

src/company_func.h

@@ -25,8 +25,8 @@ void CompanyAdminBankrupt(CompanyID company_id);
 void UpdateLandscapingLimits();
 
 bool CheckCompanyHasMoney(CommandCost &cost);
-void SubtractMoneyFromCompany(CommandCost cost);
-void SubtractMoneyFromCompanyFract(CompanyID company, CommandCost cost);
+void SubtractMoneyFromCompany(const CommandCost& cost);
+void SubtractMoneyFromCompanyFract(CompanyID company, const CommandCost& cost);
 CommandCost CheckOwnership(Owner owner, TileIndex tile = 0);
 CommandCost CheckTileOwnership(TileIndex tile);