(svn r21091) -Codechange: Add bit constants for checking NewGRFCache validity.

src/newgrf_engine.cpp

@@ -512,21 +512,21 @@ static uint32 VehicleGetVariable(const ResolverObject *object, byte variable, by
 			return GetEngineGRFID(v->engine_type);
 
 		case 0x40: // Get length of consist
-			if (!HasBit(v->grf_cache.cache_valid, 0)) {
+			if (!HasBit(v->grf_cache.cache_valid, NCVV_POSITION_CONSIST_LENGTH)) {
 				v->grf_cache.position_consist_length = PositionHelper(v, false);
-				SetBit(v->grf_cache.cache_valid, 0);
+				SetBit(v->grf_cache.cache_valid, NCVV_POSITION_CONSIST_LENGTH);
 			}
 			return v->grf_cache.position_consist_length;
 
 		case 0x41: // Get length of same consecutive wagons
-			if (!HasBit(v->grf_cache.cache_valid, 1)) {
+			if (!HasBit(v->grf_cache.cache_valid, NCVV_POSITION_SAME_ID_LENGTH)) {
 				v->grf_cache.position_same_id_length = PositionHelper(v, true);
-				SetBit(v->grf_cache.cache_valid, 1);
+				SetBit(v->grf_cache.cache_valid, NCVV_POSITION_SAME_ID_LENGTH);
 			}
 			return v->grf_cache.position_same_id_length;
 
 		case 0x42: // Consist cargo information
-			if (!HasBit(v->grf_cache.cache_valid, 2)) {
+			if (!HasBit(v->grf_cache.cache_valid, NCVV_CONSIST_CARGO_INFORMATION)) {
 				const Vehicle *u;
 				byte cargo_classes = 0;
 				uint8 common_cargos[NUM_CARGO];
@@ -577,14 +577,14 @@ static uint32 VehicleGetVariable(const ResolverObject *object, byte variable, by
 
 				uint8 common_bitnum = (common_cargo_type == CT_INVALID ? 0xFF : CargoSpec::Get(common_cargo_type)->bitnum);
 				v->grf_cache.consist_cargo_information = cargo_classes | (common_bitnum << 8) | (common_subtype << 16) | (user_def_data << 24);
-				SetBit(v->grf_cache.cache_valid, 2);
+				SetBit(v->grf_cache.cache_valid, NCVV_CONSIST_CARGO_INFORMATION);
 			}
 			return v->grf_cache.consist_cargo_information;
 
 		case 0x43: // Company information
-			if (!HasBit(v->grf_cache.cache_valid, 3)) {
+			if (!HasBit(v->grf_cache.cache_valid, NCVV_COMPANY_INFORMATION)) {
 				v->grf_cache.company_information = v->owner | (Company::IsHumanID(v->owner) ? 0 : 0x10000) | (LiveryHelper(v->engine_type, v) << 24);
-				SetBit(v->grf_cache.cache_valid, 3);
+				SetBit(v->grf_cache.cache_valid, NCVV_COMPANY_INFORMATION);
 			}
 			return v->grf_cache.company_information;
 

src/vehicle_base.h

@@ -46,6 +46,14 @@ enum VehicleFlags {
 	VF_STOP_LOADING,            ///< Don't load anymore during the next load cycle.
 };
 
+/** Bit numbers used to indicate which of the #NewGRFCache values are valid. */
+enum NewGRFCacheValidValues {
+	NCVV_POSITION_CONSIST_LENGTH   = 0, ///< This bit will be set if the NewGRF var 40 currently stored is valid.
+	NCVV_POSITION_SAME_ID_LENGTH   = 1, ///< This bit will be set if the NewGRF var 41 currently stored is valid.
+	NCVV_CONSIST_CARGO_INFORMATION = 2, ///< This bit will be set if the NewGRF var 42 currently stored is valid.
+	NCVV_COMPANY_INFORMATION       = 3, ///< This bit will be set if the NewGRF var 43 currently stored is valid.
+};
+
 /** Cached often queried (NewGRF) values */
 struct NewGRFCache {
 	/* Values calculated when they are requested for the first time after invalidating the NewGRF cache. */