dd

OpenRA.Game/Primitives/PositionalQueue.cs

@@ -6,18 +6,22 @@ namespace OpenRA.Primitives
 {
 	public class PositionalQueue<T> : IEnumerable<T>
 	{
-		T[] items;
+		Entry[] items;
 		int currentIndex = 0;
 		int end = 0;
 		int absoluteIndex = 0;
 		int size;
-		private readonly T empty;
 
-		public PositionalQueue(int size = 2, T empty = default)
+		struct Entry
 		{
-			items = new T[size];
+			public T Value;
+			public bool HasValue;
+		}
+
+		public PositionalQueue(int size = 2)
+		{
+			items = new Entry[size];
 			this.size = size;
-			this.empty = empty;
 			end = this.size - 1;
 
 		}
@@ -46,17 +50,21 @@ public void EnqueueAt(int index, T i)
 				}
 			}
 
-			if (!Equals(items[pos], empty))
+			if (items[pos].HasValue)
 			{
 				throw new ArgumentException("An element with the same key already exists in the ");
 			}
 
-			items[pos] = i;
+			items[pos] = new Entry
+			{
+				Value = i,
+				HasValue = true
+			};
 		}
 
 		void Resize(int increaseBy)
 		{
-			var temp = new T[size + increaseBy];
+			var temp = new Entry[size + increaseBy];
 
 			if (absoluteIndex > 0)
 			{
@@ -90,14 +98,14 @@ public T Dequeue()
 				absoluteIndex = 0;
 			}
 
-			return item;
+			return item.Value;
 		}
 
 		public T Peek()
 		{
 			var item = items[absoluteIndex];
 
-			return item;
+			return item.Value;
 		}
 
 		public bool HasItem()
@@ -139,9 +147,9 @@ public bool TryGet(int index, out T item)
 
 			var tItem = items[pos];
 
-			if (!Equals(tItem, empty))
+			if (tItem.HasValue)
 			{
-				item = tItem;
+				item = tItem.Value;
 				return true;
 			}