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ICSharpCode.TextEditor/Project/Src/Util/RedBlackTreeIterator.cs

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+// <file>
+//     <copyright see="prj:///doc/copyright.txt"/>
+//     <license see="prj:///doc/license.txt"/>
+//     <owner name="Daniel Grunwald" email="daniel@danielgrunwald.de"/>
+//     <version>$Revision$</version>
+// </file>
+
+using System;
+using System.Diagnostics;
+using System.Collections.Generic;
+
+namespace ICSharpCode.TextEditor.Util
+{
+	internal struct RedBlackTreeIterator<T> : IEnumerator<T>
+	{
+		internal RedBlackTreeNode<T> node;
+		
+		internal RedBlackTreeIterator(RedBlackTreeNode<T> node)
+		{
+			this.node = node;
+		}
+		
+		public bool IsValid {
+			get { return node != null; }
+		}
+		
+		public T Current {
+			get {
+				if (node != null)
+					return node.val;
+				else
+					throw new InvalidOperationException();
+			}
+		}
+		
+		object System.Collections.IEnumerator.Current {
+			get {
+				return this.Current;
+			}
+		}
+		
+		void IDisposable.Dispose()
+		{
+		}
+		
+		void System.Collections.IEnumerator.Reset()
+		{
+			throw new NotSupportedException();
+		}
+		
+		public bool MoveNext()
+		{
+			if (node == null)
+				return false;
+			if (node.right != null) {
+				node = node.right.LeftMost;
+			} else {
+				RedBlackTreeNode<T> oldNode;
+				do {
+					oldNode = node;
+					node = node.parent;
+					// we are on the way up from the right part, don't output node again
+				} while (node != null && node.right == oldNode);
+			}
+			return node != null;
+		}
+		
+		public bool MoveBack()
+		{
+			if (node == null)
+				return false;
+			if (node.left != null) {
+				node = node.left.RightMost;
+			} else {
+				RedBlackTreeNode<T> oldNode;
+				do {
+					oldNode = node;
+					node = node.parent;
+					// we are on the way up from the left part, don't output node again
+				} while (node != null && node.left == oldNode);
+			}
+			return node != null;
+		}
+	}
+}