From 533df844d894a8858aafb7b4d619683fcaddabc0 Mon Sep 17 00:00:00 2001
From: Chris Forbes <chrisf@ijw.co.nz>
Date: Sat, 5 Mar 2011 18:28:59 +1300
Subject: [PATCH] pool CellInfo[,] to save massive amounts of memory (now uses
 only 512K for CellInfos on default-sized maps)

---
 OpenRA.Mods.RA/Move/PathFinder.cs | 69 ++++++++++++++++---------------
 OpenRA.Mods.RA/Move/PathSearch.cs | 58 +++++++++++++++++++++++---
 2 files changed, 88 insertions(+), 39 deletions(-)

diff --git a/OpenRA.Mods.RA/Move/PathFinder.cs b/OpenRA.Mods.RA/Move/PathFinder.cs
index 4a64f55fe8..9be2e19f5d 100755
--- a/OpenRA.Mods.RA/Move/PathFinder.cs
+++ b/OpenRA.Mods.RA/Move/PathFinder.cs
@@ -87,12 +87,13 @@ namespace OpenRA.Mods.RA.Move
 		{
 			using (new PerfSample("Pathfinder"))
 			{
-				while (!search.queue.Empty)
-				{
-					var p = search.Expand( world );
-					if (search.heuristic(p) == 0)
-						return MakePath(search.cellInfo, p);
-				}
+				using(search)
+					while (!search.queue.Empty)
+					{
+						var p = search.Expand(world);
+						if (search.heuristic(p) == 0)
+							return MakePath(search.cellInfo, p);
+					}
 
 				// no path exists
 				return new List<int2>();
@@ -113,33 +114,35 @@ namespace OpenRA.Mods.RA.Move
 			ret.Add(pathNode);
 			CheckSanePath(ret);
 			return ret;
-		}
-
-
-
-		public List<int2> FindBidiPath(			/* searches from both ends toward each other */
-			PathSearch fromSrc,
-			PathSearch fromDest)
-		{
-			using (new PerfSample("Pathfinder"))
-			{
-				while (!fromSrc.queue.Empty && !fromDest.queue.Empty)
-				{
-					/* make some progress on the first search */
-					var p = fromSrc.Expand( world );
-
-					if (fromDest.cellInfo[p.X, p.Y].Seen && fromDest.cellInfo[p.X, p.Y].MinCost < float.PositiveInfinity)
-						return MakeBidiPath(fromSrc, fromDest, p);
-
-					/* make some progress on the second search */
-					var q = fromDest.Expand( world );
-
-					if (fromSrc.cellInfo[q.X, q.Y].Seen && fromSrc.cellInfo[q.X, q.Y].MinCost < float.PositiveInfinity)
-						return MakeBidiPath(fromSrc, fromDest, q);
-				}
-
-				return new List<int2>();
-			}
+		}
+
+
+
+		public List<int2> FindBidiPath(			/* searches from both ends toward each other */
+			PathSearch fromSrc,
+			PathSearch fromDest)
+		{
+			using (new PerfSample("Pathfinder"))
+			{
+				using (fromSrc)
+				using (fromDest)
+					while (!fromSrc.queue.Empty && !fromDest.queue.Empty)
+					{
+						/* make some progress on the first search */
+						var p = fromSrc.Expand(world);
+
+						if (fromDest.cellInfo[p.X, p.Y].Seen && fromDest.cellInfo[p.X, p.Y].MinCost < float.PositiveInfinity)
+							return MakeBidiPath(fromSrc, fromDest, p);
+
+						/* make some progress on the second search */
+						var q = fromDest.Expand(world);
+
+						if (fromSrc.cellInfo[q.X, q.Y].Seen && fromSrc.cellInfo[q.X, q.Y].MinCost < float.PositiveInfinity)
+							return MakeBidiPath(fromSrc, fromDest, q);
+					}
+
+				return new List<int2>();
+			}
 		}
 
 		static List<int2> MakeBidiPath(PathSearch a, PathSearch b, int2 p)
diff --git a/OpenRA.Mods.RA/Move/PathSearch.cs b/OpenRA.Mods.RA/Move/PathSearch.cs
index e1fb26d679..054fa504e8 100755
--- a/OpenRA.Mods.RA/Move/PathSearch.cs
+++ b/OpenRA.Mods.RA/Move/PathSearch.cs
@@ -15,7 +15,7 @@ using OpenRA.Traits;
 
 namespace OpenRA.Mods.RA.Move
 {
-	public class PathSearch
+	public class PathSearch : IDisposable
 	{
 		World world;
 		public CellInfo[ , ] cellInfo;
@@ -191,15 +191,47 @@ namespace OpenRA.Mods.RA.Move
 				search.AddInitialCell( sl );
 
 			return search;
+		}
+
+		static readonly Queue<CellInfo[,]> cellInfoPool = new Queue<CellInfo[,]>();
+
+		static CellInfo[,] GetFromPool()
+		{
+			lock (cellInfoPool)
+				return cellInfoPool.Dequeue();
+		}
+
+		static void PutBackIntoPool(CellInfo[,] ci)
+		{
+			lock (cellInfoPool)
+				cellInfoPool.Enqueue(ci);
 		}
 
 		CellInfo[ , ] InitCellInfo()
-		{
-			var cellInfo = new CellInfo[ world.Map.MapSize.X, world.Map.MapSize.Y ];
+		{
+			CellInfo[,] result = null;
+			while (cellInfoPool.Count > 0)
+			{
+				var cellInfo = GetFromPool();
+				if (cellInfo.GetUpperBound(0) != world.Map.MapSize.X - 1 ||
+					cellInfo.GetUpperBound(1) != world.Map.MapSize.Y - 1)
+				{
+					Game.Debug("Discarding old pooled CellInfo of wrong size.");
+					continue;
+				}
+
+				result = cellInfo;
+				break;
+			}
+
+			if (result == null)
+				result  = new CellInfo[ world.Map.MapSize.X, world.Map.MapSize.Y ];
+
 			for( int x = 0 ; x < world.Map.MapSize.X ; x++ )
 				for( int y = 0 ; y < world.Map.MapSize.Y ; y++ )
-					cellInfo[ x, y ] = new CellInfo( int.MaxValue, new int2( x, y ), false );
-			return cellInfo;
+					result[ x, y ] = new CellInfo( int.MaxValue, new int2( x, y ), false );
+
+			return result;
 		}
 
 		public static Func<int2, int> DefaultEstimator( int2 destination )
@@ -211,6 +243,20 @@ namespace OpenRA.Mods.RA.Move
 				int straight = Math.Abs( d.X - d.Y );
 				return (3400 * diag / 24) + (100 * straight);
 			};
-		}
+		}
+
+		bool disposed;
+		public void Dispose()
+		{
+			if (disposed)
+				return;
+
+			disposed = true;
+			GC.SuppressFinalize(this);
+			PutBackIntoPool(cellInfo);
+			cellInfo = null;
+		}
+
+		~PathSearch() { Dispose(); }
 	}
 }