From 8a91805c059c40ca4e75a2e6053724d3c8f11582 Mon Sep 17 00:00:00 2001
From: celestar <celestar@openttd.org>
Date: Thu, 30 Mar 2006 11:21:36 +0000
Subject: [PATCH] (svn r4172) -Codechange: Added a few accessors to work with
 ShipDepots and Locks

---
 water_cmd.c | 25 +++++--------------------
 water_map.h | 28 ++++++++++++++++++++++++++--
 2 files changed, 31 insertions(+), 22 deletions(-)

diff --git a/water_cmd.c b/water_cmd.c
index 0aad1df860..86434846ac 100644
--- a/water_cmd.c
+++ b/water_cmd.c
@@ -41,14 +41,6 @@ const SpriteID _water_shore_sprites[15] = {
 
 static void FloodVehicle(Vehicle *v);
 
-static bool IsClearWaterTile(TileIndex tile)
-{
-	return
-		IsTileType(tile, MP_WATER) &&
-		_m[tile].m5 == 0 &&
-		GetTileSlope(tile, NULL) == 0;
-}
-
 /** Build a ship depot.
  * @param x,y tile coordinates where ship depot is built
  * @param p1 depot direction (0 == X or 1 == Y)
@@ -103,16 +95,17 @@ static int32 RemoveShipDepot(TileIndex tile, uint32 flags)
 {
 	TileIndex tile2;
 
+	if (!IsShipDepot(tile)) return CMD_ERROR;
 	if (!CheckTileOwnership(tile)) return CMD_ERROR;
 	if (!EnsureNoVehicle(tile)) return CMD_ERROR;
 
-	tile2 = tile + ((_m[tile].m5 & 2) ? TileDiffXY(0, 1) : TileDiffXY(1, 0));
+	tile2 = GetOtherShipDepotTile(tile);
 
 	if (!EnsureNoVehicle(tile2)) return CMD_ERROR;
 
 	if (flags & DC_EXEC) {
-		/* Kill the depot */
-		DoDeleteDepot(tile);
+		/* Kill the depot, which is registered at the northernmost tile. Use that one */
+		DoDeleteDepot(tile2 < tile ? tile2 : tile);
 
 		MakeWater(tile);
 		MakeWater(tile2);
@@ -156,7 +149,7 @@ static int32 DoBuildShiplift(TileIndex tile, DiagDirection dir, uint32 flags)
 
 static int32 RemoveShiplift(TileIndex tile, uint32 flags)
 {
-	TileIndexDiff delta = TileOffsByDir(GB(_m[tile].m5, 0, 2));
+	TileIndexDiff delta = TileOffsByDir(GetLockDirection(tile));
 
 	// make sure no vehicle is on the tile.
 	if (!EnsureNoVehicle(tile) || !EnsureNoVehicle(tile + delta) || !EnsureNoVehicle(tile - delta))
@@ -322,14 +315,6 @@ static int32 ClearTile_Water(TileIndex tile, byte flags)
 		// ship depot
 		if (flags & DC_AUTO) return_cmd_error(STR_2004_BUILDING_MUST_BE_DEMOLISHED);
 
-		switch (m5) {
-			case 0x80: break;
-			case 0x81: tile -= TileDiffXY(1, 0); break;
-			case 0x82: break;
-			case 0x83: tile -= TileDiffXY(0, 1); break;
-			default:   return CMD_ERROR;
-		}
-
 		return RemoveShipDepot(tile, flags);
 	}
 }
diff --git a/water_map.h b/water_map.h
index 2cb884ab71..8fbc770f1c 100644
--- a/water_map.h
+++ b/water_map.h
@@ -5,7 +5,8 @@
 
 typedef enum DepotPart {
 	DEPOT_NORTH = 0x80,
-	DEPOT_SOUTH = 0x81
+	DEPOT_SOUTH = 0x81,
+	DEPOT_END   = 0x84,
 } DepotPart;
 
 typedef enum LockPart {
@@ -14,6 +15,30 @@ typedef enum LockPart {
 	LOCK_UPPER  = 0x18
 } LockPart;
 
+static inline bool IsClearWaterTile(TileIndex tile)
+{
+	return
+		IsTileType(tile, MP_WATER) &&
+		_m[tile].m5 == 0 &&
+		GetTileSlope(tile, NULL) == 0;
+}
+
+static inline TileIndex GetOtherShipDepotTile(TileIndex t)
+{
+	return t + (HASBIT(_m[t].m5, 0) ? -1 : 1) * (HASBIT(_m[t].m5, 1) ? TileDiffXY(0, 1) : TileDiffXY(1, 0));
+}
+
+static inline TileIndex IsShipDepot(TileIndex t)
+{
+	return IS_INT_INSIDE(_m[t].m5, DEPOT_NORTH, DEPOT_END);
+}
+
+static inline DiagDirection GetLockDirection(TileIndex t)
+{
+	return (DiagDirection)GB(_m[t].m5, 0, 2);
+}
+
+
 static inline void MakeWater(TileIndex t)
 {
 	SetTileType(t, MP_WATER);
@@ -24,7 +49,6 @@ static inline void MakeWater(TileIndex t)
 	_m[t].m5 = 0;
 }
 
-
 static inline void MakeShore(TileIndex t)
 {
 	SetTileType(t, MP_WATER);