(svn r3773) Shove some semantics down ottd's throat by replacing ints and magic numbers by enums and some related changes

6 files changed, 79 insertions, 62 deletions

diff --git a/functions.h b/functions.h
index 58304bf6b..39d270ff1 100644
--- a/functions.h
+++ b/functions.h
@@ -215,7 +215,6 @@ bool CheckIfAuthorityAllows(TileIndex tile);
 Town *ClosestTownFromTile(TileIndex tile, uint threshold);
 void ChangeTownRating(Town *t, int add, int max);
 
-uint GetRoadBitsByTile(TileIndex tile);
 int GetTownRadiusGroup(const Town *t, TileIndex tile);
 void ShowNetworkChatQueryWindow(byte desttype, byte dest);
 void ShowNetworkGiveMoneyWindow(byte player);
diff --git a/road_cmd.c b/road_cmd.c
index b774484a3..a4480b669 100644
--- a/road_cmd.c
+++ b/road_cmd.c
@@ -73,11 +73,6 @@ static bool CheckAllowRemoveRoad(TileIndex tile, RoadBits remove, bool* edge_roa
 	return true;
 }
 
-uint GetRoadBitsByTile(TileIndex tile)
-{
-	uint32 r = GetTileTrackStatus(tile, TRANSPORT_ROAD);
-	return (byte)(r | (r >> 8));
-}
 
 /** Delete a piece of road.
  * @param x,y tile coordinates for road construction
@@ -158,30 +153,33 @@ int32 CmdRemoveRoad(int x, int y, uint32 flags, uint32 p1, uint32 p2)
 
 			switch (GetRoadType(ti.tile)) {
 				case ROAD_NORMAL: {
-					byte c = pieces, t2;
+					RoadBits present = GetRoadBits(ti.tile);
+					RoadBits c = pieces;
 
-					if (ti.tileh != 0  && (ti.map5 == ROAD_Y || ti.map5 == ROAD_X)) {
+					if (ti.tileh != 0  && (present == ROAD_Y || present == ROAD_X)) {
 						c |= (c & 0xC) >> 2;
 						c |= (c & 0x3) << 2;
 					}
 
 					// limit the bits to delete to the existing bits.
-					if ((c &= ti.map5) == 0) goto return_error;
+					c &= present;
+					if (c == 0) goto return_error;
 
 					// calculate the cost
-					t2 = c;
 					cost = 0;
-					do {
-						if (t2 & 1) cost += _price.remove_road;
-					} while (t2 >>= 1);
+					if (c & ROAD_NW) cost += _price.remove_road;
+					if (c & ROAD_SW) cost += _price.remove_road;
+					if (c & ROAD_SE) cost += _price.remove_road;
+					if (c & ROAD_NE) cost += _price.remove_road;
 
 					if (flags & DC_EXEC) {
 						ChangeTownRating(t, -road_remove_cost[(byte)edge_road], RATING_ROAD_MINIMUM);
 
-						_m[tile].m5 ^= c;
-						if (GetRoadBits(tile) == 0) {
+						present ^= c;
+						if (present == 0) {
 							DoClearSquare(tile);
 						} else {
+							SetRoadBits(tile, present);
 							MarkTileDirtyByTile(tile);
 						}
 					}
@@ -248,10 +246,10 @@ static const RoadBits _valid_tileh_slopes_road[][15] = {
 };
 
 
-static uint32 CheckRoadSlope(int tileh, byte *pieces, byte existing)
+static uint32 CheckRoadSlope(int tileh, RoadBits* pieces, RoadBits existing)
 {
 	if (!IsSteepTileh(tileh)) {
-		byte road_bits = *pieces | existing;
+		RoadBits road_bits = *pieces | existing;
 
 		// no special foundation
 		if ((~_valid_tileh_slopes_road[0][tileh] & road_bits) == 0) {
@@ -266,11 +264,11 @@ static uint32 CheckRoadSlope(int tileh, byte *pieces, byte existing)
 		}
 
 		// partly leveled up tile, only if there's no road on that tile
-		if (!existing && (tileh == 1 || tileh == 2 || tileh == 4 || tileh == 8)) {
+		if (existing == 0 && (tileh == 1 || tileh == 2 || tileh == 4 || tileh == 8)) {
 			// force full pieces.
 			*pieces |= (*pieces & 0xC) >> 2;
 			*pieces |= (*pieces & 0x3) << 2;
-			return (*pieces == (ROAD_NE|ROAD_SW) || *pieces == (ROAD_SE|ROAD_NW)) ? _price.terraform : CMD_ERROR;
+			return (*pieces == ROAD_X || *pieces == ROAD_Y) ? _price.terraform : CMD_ERROR;
 		}
 	}
 	return CMD_ERROR;
@@ -285,14 +283,16 @@ int32 CmdBuildRoad(int x, int y, uint32 flags, uint32 p1, uint32 p2)
 {
 	TileInfo ti;
 	int32 cost;
-	byte pieces = (byte)p1, existing = 0;
+	RoadBits existing = 0;
+	RoadBits pieces;
 	TileIndex tile;
 
 	SET_EXPENSES_TYPE(EXPENSES_CONSTRUCTION);
 
 	/* Road pieces are max 4 bitset values (NE, NW, SE, SW) and town can only be non-zero
 	 * if a non-player is building the road */
-	if ((pieces >> 4) || (_current_player < MAX_PLAYERS && p2 != 0) || !IsTownIndex(p2)) return CMD_ERROR;
+	if ((p1 >> 4) || (_current_player < MAX_PLAYERS && p2 != 0) || !IsTownIndex(p2)) return CMD_ERROR;
+	pieces = p1;
 
 	FindLandscapeHeight(&ti, x, y);
 	tile = ti.tile;
@@ -302,16 +302,16 @@ int32 CmdBuildRoad(int x, int y, uint32 flags, uint32 p1, uint32 p2)
 
 	switch (ti.type) {
 		case MP_STREET:
-			switch (GetRoadType(ti.tile)) {
+			switch (GetRoadType(tile)) {
 				case ROAD_NORMAL:
-					if ((GetRoadBits(ti.tile) & pieces) == pieces) {
+					existing = GetRoadBits(tile);
+					if ((existing & pieces) == pieces) {
 						return_cmd_error(STR_1007_ALREADY_BUILT);
 					}
-					existing = ti.map5;
 					break;
 
 				case ROAD_CROSSING:
-					if (pieces != GetCrossingRoadBits(ti.tile)) { // XXX is this correct?
+					if (pieces != GetCrossingRoadBits(tile)) { // XXX is this correct?
 						return_cmd_error(STR_1007_ALREADY_BUILT);
 					}
 					goto do_clear;
@@ -363,7 +363,7 @@ int32 CmdBuildRoad(int x, int y, uint32 flags, uint32 p1, uint32 p2)
 			if ((ti.map5 & 0xC0) != 0xC0) goto do_clear;
 
 			/* only allow roads pertendicular to bridge */
-			if (((pieces & 5U) != 0) == ((ti.map5 & 0x01U) != 0)) goto do_clear;
+			if (((pieces & ROAD_Y) != 0) == ((ti.map5 & 0x01U) != 0)) goto do_clear;
 
 			/* check if clear land under bridge */
 			if ((ti.map5 & 0xF8) == 0xE8) { /* road under bridge */
@@ -396,26 +396,23 @@ do_clear:;
 	if (cost && (!_patches.build_on_slopes || _is_old_ai_player))
 		return CMD_ERROR;
 
-	if (ti.type != MP_STREET || GetRoadType(ti.tile) != ROAD_NORMAL) {
-		cost += DoCommandByTile(tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
-	} else {
+	if (ti.type == MP_STREET && GetRoadType(tile) == ROAD_NORMAL) {
 		// Don't put the pieces that already exist
-		pieces &= ~ti.map5;
+		pieces &= ComplementRoadBits(existing);
+	} else {
+		cost += DoCommandByTile(tile, 0, 0, flags, CMD_LANDSCAPE_CLEAR);
 	}
 
-	{
-		byte t = pieces;
-		while (t) {
-			if (t & 1) cost += _price.build_road;
-			t >>= 1;
-		}
-	}
+	if (pieces & ROAD_NW) cost += _price.build_road;
+	if (pieces & ROAD_SW) cost += _price.build_road;
+	if (pieces & ROAD_SE) cost += _price.build_road;
+	if (pieces & ROAD_NE) cost += _price.build_road;
 
 	if (flags & DC_EXEC) {
-		if (ti.type != MP_STREET) {
-			MakeRoadNormal(tile, _current_player, pieces, p2);
+		if (ti.type == MP_STREET) {
+			SetRoadBits(tile, existing | pieces);
 		} else {
-			_m[tile].m5 |= pieces;
+			MakeRoadNormal(tile, _current_player, pieces, p2);
 		}
 
 		MarkTileDirtyByTile(tile);
diff --git a/road_gui.c b/road_gui.c
index 40096a474..a339e528a 100644
--- a/road_gui.c
+++ b/road_gui.c
@@ -2,6 +2,7 @@
 
 #include "stdafx.h"
 #include "openttd.h"
+#include "road_map.h"
 #include "table/sprites.h"
 #include "table/strings.h"
 #include "functions.h"
@@ -72,7 +73,7 @@ static void BuildRoadOutsideStation(TileIndex tile, int direction)
 	static const byte _roadbits_by_dir[4] = {2,1,8,4};
 	tile += TileOffsByDir(direction);
 	// if there is a roadpiece just outside of the station entrance, build a connecting route
-	if (IsTileType(tile, MP_STREET) && !(_m[tile].m5 & 0x20)) {
+	if (IsTileType(tile, MP_STREET) && GetRoadType(tile) == ROAD_NORMAL) {
 		DoCommandP(tile, _roadbits_by_dir[direction], 0, NULL, CMD_BUILD_ROAD);
 	}
 }
diff --git a/road_map.c b/road_map.c
index ca35d8358..45aba0605 100644
--- a/road_map.c
+++ b/road_map.c
@@ -2,6 +2,7 @@
 
 #include "stdafx.h"
 #include "openttd.h"
+#include "functions.h"
 #include "road_map.h"
 #include "station.h"
 
@@ -42,3 +43,10 @@ RoadBits GetAnyRoadBits(TileIndex tile)
 		default: return 0;
 	}
 }
+
+
+TrackBits GetAnyRoadTrackBits(TileIndex tile)
+{
+	uint32 r = GetTileTrackStatus(tile, TRANSPORT_ROAD);
+	return (byte)(r | (r >> 8));
+}
diff --git a/road_map.h b/road_map.h
index 120688474..1aa3ea88c 100644
--- a/road_map.h
+++ b/road_map.h
@@ -33,6 +33,12 @@ static inline RoadBits GetRoadBits(TileIndex tile)
 	return GB(_m[tile].m5, 0, 4);
 }
 
+static inline void SetRoadBits(TileIndex tile, RoadBits r)
+{
+	SB(_m[tile].m5, 0, 4, r);
+}
+
+
 static inline RoadBits GetCrossingRoadBits(TileIndex tile)
 {
 	return _m[tile].m5 & 8 ? ROAD_Y : ROAD_X;
@@ -67,6 +73,9 @@ static inline RoadType GetRoadType(TileIndex tile)
 RoadBits GetAnyRoadBits(TileIndex);
 
 
+TrackBits GetAnyRoadTrackBits(TileIndex tile);
+
+
 static inline void MakeRoadNormal(TileIndex t, Owner owner, RoadBits bits, uint town)
 {
 	SetTileType(t, MP_STREET);
diff --git a/town_cmd.c b/town_cmd.c
index da586af45..920601397 100644
--- a/town_cmd.c
+++ b/town_cmd.c
@@ -461,17 +461,17 @@ void OnTick_Town(void)
 	}
 }
 
-static byte GetTownRoadMask(TileIndex tile)
+static RoadBits GetTownRoadMask(TileIndex tile)
 {
-	byte b = GetRoadBitsByTile(tile);
-	byte r = 0;
+	TrackBits b = GetAnyRoadTrackBits(tile);
+	RoadBits r = 0;
 
-	if (b & 0x01) r |= 10;
-	if (b & 0x02) r |=  5;
-	if (b & 0x04) r |=  9;
-	if (b & 0x08) r |=  6;
-	if (b & 0x10) r |=  3;
-	if (b & 0x20) r |= 12;
+	if (b & TRACK_BIT_X)     r |= ROAD_X;
+	if (b & TRACK_BIT_Y)     r |= ROAD_Y;
+	if (b & TRACK_BIT_UPPER) r |= ROAD_NE | ROAD_NW;
+	if (b & TRACK_BIT_LOWER) r |= ROAD_SE | ROAD_SW;
+	if (b & TRACK_BIT_LEFT)  r |= ROAD_NW | ROAD_SW;
+	if (b & TRACK_BIT_RIGHT) r |= ROAD_NE | ROAD_SE;
 	return r;
 }
 
@@ -486,7 +486,7 @@ static bool IsRoadAllowedHere(TileIndex tile, int dir)
 
 	for (;;) {
 		// Check if there already is a road at this point?
-		if (GetRoadBitsByTile(tile) == 0) {
+		if (GetAnyRoadTrackBits(tile) == 0) {
 			// No, try to build one in the direction.
 			// if that fails clear the land, and if that fails exit.
 			// This is to make sure that we can build a road here later.
@@ -567,17 +567,20 @@ static void LevelTownLand(TileIndex tile)
 
 #define IS_WATER_TILE(t) (IsTileType((t), MP_WATER) && _m[(t)].m5 == 0)
 
-static void GrowTownInTile(TileIndex *tile_ptr, uint mask, int block, Town *t1)
+static void GrowTownInTile(TileIndex* tile_ptr, RoadBits mask, int block, Town* t1)
 {
-	int a,b,rcmd;
+	RoadBits rcmd;
 	TileIndex tmptile;
-	uint i;
+	DiagDirection i;
 	int j;
 	TileIndex tile = *tile_ptr;
 
 	TILE_ASSERT(tile);
 
 	if (mask == 0) {
+		int a;
+		int b;
+
 		// Tile has no road. First reset the status counter
 		// to say that this is the last iteration.
 		_grow_town_result = 0;
@@ -618,6 +621,7 @@ static void GrowTownInTile(TileIndex *tile_ptr, uint mask, int block, Town *t1)
 		_grow_town_result = 0;
 		rcmd = 1 << (block ^ 2);
 	} else {
+		int i;
 
 		// Reached a tunnel? Then continue at the other side of it.
 		if (IsTileType(tile, MP_TUNNELBRIDGE) && (_m[tile].m5& ~3) == 4) {
@@ -665,10 +669,10 @@ static void GrowTownInTile(TileIndex *tile_ptr, uint mask, int block, Town *t1)
 	// Determine direction of slope,
 	//  and build a road if not a special slope.
 	switch (GetTileSlope(tile, NULL)) {
-		case  3: i = 0; break;
-		case  6: i = 3; break;
-		case  9: i = 1; break;
-		case 12: i = 2; break;
+		case  3: i = DIAGDIR_NE; break;
+		case  6: i = DIAGDIR_NW; break;
+		case  9: i = DIAGDIR_SE; break;
+		case 12: i = DIAGDIR_SW; break;
 
 		default:
 build_road_and_exit:
@@ -714,7 +718,6 @@ build_road_and_exit:
 // Returns true if a house was built, or no if the build failed.
 static int GrowTownAtRoad(Town *t, TileIndex tile)
 {
-	uint mask;
 	int block = 5; // special case
 
 	TILE_ASSERT(tile);
@@ -724,7 +727,7 @@ static int GrowTownAtRoad(Town *t, TileIndex tile)
 
 	do {
 		// Get a bitmask of the road blocks on a tile
-		mask = GetTownRoadMask(tile);
+		RoadBits mask = GetTownRoadMask(tile);
 
 		// Try to grow the town from this point
 		GrowTownInTile(&tile,mask,block,t);
@@ -761,7 +764,7 @@ static int GrowTownAtRoad(Town *t, TileIndex tile)
 // Generate a random road block
 // The probability of a straight road
 // is somewhat higher than a curved.
-static int GenRandomRoadBits(void)
+static RoadBits GenRandomRoadBits(void)
 {
 	uint32 r = Random();
 	uint a = GB(r, 0, 2);
@@ -801,7 +804,7 @@ static bool GrowTown(Town *t)
 	// Find a road that we can base the construction on.
 	tile = t->xy;
 	for (ptr = _town_coord_mod; ptr != endof(_town_coord_mod); ++ptr) {
-		if (GetRoadBitsByTile(tile) != 0) {
+		if (GetAnyRoadTrackBits(tile) != 0) {
 			int r = GrowTownAtRoad(t, tile);
 			_current_player = old_player;
 			return r;