(svn r11031) -Codechange: reduce the amount of duplication of bit counting functions. Based on patches by skidd13, SmatZ and Belugas.

src/economy.cpp

@@ -70,7 +70,7 @@ Money CalculateCompanyValue(const Player* p)
 		uint num = 0;
 
 		FOR_ALL_STATIONS(st) {
-			if (st->owner == owner) num += CountBitsSet(st->facilities);
+			if (st->owner == owner) num += COUNTBITS(st->facilities);
 		}
 
 		value.AddCost(num * _price.station_value * 25);
@@ -146,7 +146,7 @@ int UpdateCompanyRatingAndValue(Player *p, bool update)
 		const Station* st;
 
 		FOR_ALL_STATIONS(st) {
-			if (st->owner == owner) num += CountBitsSet(st->facilities);
+			if (st->owner == owner) num += COUNTBITS(st->facilities);
 		}
 		_score_part[owner][SCORE_STATIONS] = num;
 	}
@@ -191,7 +191,7 @@ int UpdateCompanyRatingAndValue(Player *p, bool update)
 
 /* Generate score for variety of cargo */
 	{
-		uint num = CountBitsSet(p->cargo_types);
+		uint num = COUNTBITS(p->cargo_types);
 		_score_part[owner][SCORE_CARGO] = num;
 		if (update) p->cargo_types = 0;
 	}

src/functions.h

@@ -136,7 +136,6 @@ uint GetTownRadiusGroup(const Town* t, TileIndex tile);
 void ShowHighscoreTable(int difficulty, int8 rank);
 
 int FindFirstBit(uint32 x);
-int CountBitsSet(uint32 value);
 
 void AfterLoadTown();
 void UpdatePatches();

src/macros.h

@@ -420,6 +420,28 @@ static inline int KillFirstBit2x64(int value)
 	}
 }
 
+/**
+ * Counts the number of set bits in a variable.
+ *
+ * @param value the value to count the number of bits in.
+ * @return the number of bits.
+ */
+template<typename T> static inline uint COUNTBITS(T value)
+{
+	uint num;
+
+	/* This loop is only called once for every bit set by clearing the lowest
+	 * bit in each loop. The number of bits is therefore equal to the number of
+	 * times the loop was called. It was found at the following website:
+	 * http://graphics.stanford.edu/~seander/bithacks.html */
+
+	for (num = 0; value != 0; num++) {
+		value &= (T)(value - 1);
+	}
+
+	return num;
+}
+
 /**
  * Returns true if value a has only one bit set to 1
  *

src/misc.cpp

@@ -273,22 +273,6 @@ int FindFirstBit(uint32 value)
 	return i;
 }
 
-int CountBitsSet(uint32 value)
-{
-	int num;
-
-	/* This loop is only called once for every bit set by clearing the lowest
-	 * bit in each loop. The number of bits is therefore equal to the number of
-	 * times the loop was called. It was found at the following website:
-	 * http://graphics.stanford.edu/~seander/bithacks.html */
-
-	for (num = 0; value != 0; num++) {
-		value &= value - 1;
-	}
-
-	return num;
-}
-
 static void Save_NAME()
 {
 	int i;

src/road_cmd.cpp

@@ -33,19 +33,6 @@
 #include "tunnel_map.h"
 #include "misc/autoptr.hpp"
 
-
-static uint CountRoadBits(RoadBits r)
-{
-	uint count = 0;
-
-	if (r & ROAD_NW) ++count;
-	if (r & ROAD_SW) ++count;
-	if (r & ROAD_SE) ++count;
-	if (r & ROAD_NE) ++count;
-	return count;
-}
-
-
 bool CheckAllowRemoveRoad(TileIndex tile, RoadBits remove, Owner owner, bool *edge_road, RoadType rt)
 {
 	RoadBits present;
@@ -225,7 +212,7 @@ CommandCost CmdRemoveRoad(TileIndex tile, uint32 flags, uint32 p1, uint32 p2)
 					MarkTileDirtyByTile(tile);
 				}
 			}
-			return CommandCost(CountRoadBits(c) * _price.remove_road);
+			return CommandCost(COUNTBITS(c) * _price.remove_road);
 		}
 
 		case ROAD_TILE_CROSSING: {
@@ -487,7 +474,7 @@ do_clear:;
 		pieces &= ComplementRoadBits(existing);
 	}
 
-	cost.AddCost(CountRoadBits(pieces) * _price.build_road);
+	cost.AddCost(COUNTBITS(pieces) * _price.build_road);
 	if (IsTileType(tile, MP_TUNNELBRIDGE)) {
 		/* Pay for *every* tile of the bridge or tunnel */
 		cost.MultiplyCost(DistanceManhattan(IsTunnel(tile) ? GetOtherTunnelEnd(tile) : GetOtherBridgeEnd(tile), tile));

src/roadveh_cmd.cpp

@@ -1083,7 +1083,7 @@ static void RoadZPosAffectSpeed(Vehicle *v, byte old_z)
 static int PickRandomBit(uint bits)
 {
 	uint i;
-	uint num = RandomRange(CountBitsSet(bits));
+	uint num = RandomRange(COUNTBITS(bits));
 
 	for (i = 0; !(bits & 1) || (int)--num >= 0; bits >>= 1, i++) {}
 	return i;

src/vehicle_gui.cpp

@@ -475,14 +475,6 @@ uint ShowAdditionalText(int x, int y, uint w, EngineID engine)
 	return DrawStringMultiLine(x, y, STR_02BD, w);
 }
 
-/** Count the number of bits that are set in a mask */
-static uint CountBits(uint32 mask)
-{
-	uint c = 0;
-	for (; mask != 0; mask >>= 1) if (HASBIT(mask, 0)) c++;
-	return c;
-}
-
 /** Display list of cargo types of the engine, for the purchase information window */
 uint ShowRefitOptionsList(int x, int y, uint w, EngineID engine)
 {
@@ -493,7 +485,7 @@ uint ShowRefitOptionsList(int x, int y, uint w, EngineID engine)
 	char *b = _userstring;
 
 	/* Draw nothing if the engine is not refittable */
-	if (CountBits(cmask) <= 1) return 0;
+	if (COUNTBITS(cmask) <= 1) return 0;
 
 	b = InlineString(b, STR_PURCHASE_INFO_REFITTABLE_TO);
 
@@ -503,7 +495,7 @@ uint ShowRefitOptionsList(int x, int y, uint w, EngineID engine)
 	} else {
 		/* Check if we are able to refit to more cargo types and unable to. If
 		 * so, invert the cargo types to list those that we can't refit to. */
-		if (CountBits(cmask ^ lmask) < CountBits(cmask)) {
+		if (COUNTBITS(cmask ^ lmask) < COUNTBITS(cmask)) {
 			cmask ^= lmask;
 			b = InlineString(b, STR_PURCHASE_INFO_ALL_BUT);
 		}