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ICSharpCode.TextEditor/Project/Src/Document/HighlightingStrategy/SpanStack.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.Collections.Generic;
+
+namespace ICSharpCode.TextEditor.Document
+{
+	/// <summary>
+	/// A stack of Span instances. Works like Stack&lt;Span&gt;, but can be cloned quickly
+	/// because it is implemented as linked list.
+	/// </summary>
+	public sealed class SpanStack : ICloneable, IEnumerable<Span>
+	{
+		internal sealed class StackNode
+		{
+			public readonly StackNode Previous;
+			public readonly Span Data;
+			
+			public StackNode(StackNode previous, Span data)
+			{
+				this.Previous = previous;
+				this.Data = data;
+			}
+		}
+		
+		StackNode top = null;
+		
+		public Span Pop()
+		{
+			Span s = top.Data;
+			top = top.Previous;
+			return s;
+		}
+		
+		public Span Peek()
+		{
+			return top.Data;
+		}
+		
+		public void Push(Span s)
+		{
+			top = new StackNode(top, s);
+		}
+		
+		public bool IsEmpty {
+			get {
+				return top == null;
+			}
+		}
+		
+		public SpanStack Clone()
+		{
+			SpanStack n = new SpanStack();
+			n.top = this.top;
+			return n;
+		}
+		object ICloneable.Clone()
+		{
+			return this.Clone();
+		}
+		
+		public Enumerator GetEnumerator()
+		{
+			return new Enumerator(new StackNode(top, null));
+		}
+		IEnumerator<Span> IEnumerable<Span>.GetEnumerator()
+		{
+			return this.GetEnumerator();
+		}
+		System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
+		{
+			return this.GetEnumerator();
+		}
+		
+		public struct Enumerator : IEnumerator<Span>
+		{
+			StackNode c;
+			
+			internal Enumerator(StackNode node)
+			{
+				c = node;
+			}
+			
+			public Span Current {
+				get {
+					return c.Data;
+				}
+			}
+			
+			object System.Collections.IEnumerator.Current {
+				get {
+					return c.Data;
+				}
+			}
+			
+			public void Dispose()
+			{
+				c = null;
+			}
+			
+			public bool MoveNext()
+			{
+				c = c.Previous;
+				return c != null;
+			}
+			
+			public void Reset()
+			{
+				throw new NotSupportedException();
+			}
+		}
+	}
+}