1 files changed, 219 insertions, 0 deletions
diff --git a/Software/Visual_Studio/Scripting/Tango.Scripting.Editors/Document/ISegment.cs b/Software/Visual_Studio/Scripting/Tango.Scripting.Editors/Document/ISegment.cs
new file mode 100644
index 000000000..80eb63352
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+++ b/Software/Visual_Studio/Scripting/Tango.Scripting.Editors/Document/ISegment.cs
@@ -0,0 +1,219 @@
+// Copyright (c) AlphaSierraPapa for the SharpDevelop Team (for details please see \doc\copyright.txt)
+// This code is distributed under the GNU LGPL (for details please see \doc\license.txt)
+
+using System;
+using System.Diagnostics;
+using Tango.Scripting.Editors.Utils;
+using System.Globalization;
+
+namespace Tango.Scripting.Editors.Document
+{
+	/// <summary>
+	/// An (Offset,Length)-pair.
+	/// </summary>
+	/// <seealso cref="TextSegment"/>
+	/// <seealso cref="AnchorSegment"/>
+	public interface ISegment
+	{
+		/// <summary>
+		/// Gets the start offset of the segment.
+		/// </summary>
+		int Offset { get; }
+		
+		/// <summary>
+		/// Gets the length of the segment.
+		/// </summary>
+		/// <remarks>Must not be negative.</remarks>
+		int Length { get; }
+		
+		/// <summary>
+		/// Gets the end offset of the segment.
+		/// </summary>
+		/// <remarks>EndOffset = Offset + Length;</remarks>
+		int EndOffset { get; }
+	}
+	
+	static class SegmentExtensions
+	{
+		/// <summary>
+		/// Gets whether the segment contains the offset.
+		/// </summary>
+		/// <returns>
+		/// True, if offset is between segment.Start and segment.End (inclusive); otherwise, false.
+		/// </returns>
+		public static bool Contains(this ISegment segment, int offset)
+		{
+			int start = segment.Offset;
+			int end = start + segment.Length;
+			return offset >= start && offset <= end;
+		}
+		
+		/// <summary>
+		/// Gets the overlapping portion of the segments.
+		/// Returns SimpleSegment.Invalid if the segments don't overlap.
+		/// </summary>
+		public static SimpleSegment GetOverlap(this ISegment segment, ISegment other)
+		{
+			int start = Math.Max(segment.Offset, other.Offset);
+			int end = Math.Min(segment.EndOffset, other.EndOffset);
+			if (end < start)
+				return SimpleSegment.Invalid;
+			else
+				return new SimpleSegment(start, end - start);
+		}
+	}
+	
+	/// <summary>
+	/// Represents a simple segment (Offset,Length pair) that is not automatically updated
+	/// on document changes.
+	/// </summary>
+	struct SimpleSegment : IEquatable<SimpleSegment>, ISegment
+	{
+		public static readonly SimpleSegment Invalid = new SimpleSegment(-1, -1);
+		
+		public readonly int Offset, Length;
+		
+		int ISegment.Offset {
+			get { return Offset; }
+		}
+		
+		int ISegment.Length {
+			get { return Length; }
+		}
+		
+		public int EndOffset {
+			get {
+				return Offset + Length;
+			}
+		}
+		
+		public SimpleSegment(int offset, int length)
+		{
+			this.Offset = offset;
+			this.Length = length;
+		}
+		
+		public SimpleSegment(ISegment segment)
+		{
+			Debug.Assert(segment != null);
+			this.Offset = segment.Offset;
+			this.Length = segment.Length;
+		}
+		
+		public override int GetHashCode()
+		{
+			unchecked {
+				return Offset + 10301 * Length;
+			}
+		}
+		
+		public override bool Equals(object obj)
+		{
+			return (obj is SimpleSegment) && Equals((SimpleSegment)obj);
+		}
+		
+		public bool Equals(SimpleSegment other)
+		{
+			return this.Offset == other.Offset && this.Length == other.Length;
+		}
+		
+		public static bool operator ==(SimpleSegment left, SimpleSegment right)
+		{
+			return left.Equals(right);
+		}
+		
+		public static bool operator !=(SimpleSegment left, SimpleSegment right)
+		{
+			return !left.Equals(right);
+		}
+		
+		public override string ToString()
+		{
+			return "[Offset=" + Offset.ToString(CultureInfo.InvariantCulture) + ", Length=" + Length.ToString(CultureInfo.InvariantCulture) + "]";
+		}
+	}
+	
+	/// <summary>
+	/// A segment using <see cref="TextAnchor"/>s as start and end positions.
+	/// </summary>
+	/// <remarks>
+	/// <para>
+	/// For the constructors creating new anchors, the start position will be AfterInsertion and the end position will be BeforeInsertion.
+	/// Should the end position move before the start position, the segment will have length 0.
+	/// </para>
+	/// </remarks>
+	/// <seealso cref="ISegment"/>
+	/// <seealso cref="TextSegment"/>
+	public sealed class AnchorSegment : ISegment
+	{
+		readonly TextAnchor start, end;
+		
+		/// <inheritdoc/>
+		public int Offset {
+			get { return start.Offset; }
+		}
+		
+		/// <inheritdoc/>
+		public int Length {
+			get {
+				// Math.Max takes care of the fact that end.Offset might move before start.Offset.
+				return Math.Max(0, end.Offset - start.Offset);
+			}
+		}
+		
+		/// <inheritdoc/>
+		public int EndOffset {
+			get {
+				// Math.Max takes care of the fact that end.Offset might move before start.Offset.
+				return Math.Max(start.Offset, end.Offset);
+			}
+		}
+		
+		/// <summary>
+		/// Creates a new AnchorSegment using the specified anchors.
+		/// The anchors must have <see cref="TextAnchor.SurviveDeletion"/> set to true.
+		/// </summary>
+		public AnchorSegment(TextAnchor start, TextAnchor end)
+		{
+			if (start == null)
+				throw new ArgumentNullException("start");
+			if (end == null)
+				throw new ArgumentNullException("end");
+			if (!start.SurviveDeletion)
+				throw new ArgumentException("Anchors for AnchorSegment must use SurviveDeletion", "start");
+			if (!end.SurviveDeletion)
+				throw new ArgumentException("Anchors for AnchorSegment must use SurviveDeletion", "end");
+			this.start = start;
+			this.end = end;
+		}
+		
+		/// <summary>
+		/// Creates a new AnchorSegment that creates new anchors.
+		/// </summary>
+		public AnchorSegment(TextDocument document, ISegment segment)
+			: this(document, ThrowUtil.CheckNotNull(segment, "segment").Offset, segment.Length)
+		{
+		}
+		
+		/// <summary>
+		/// Creates a new AnchorSegment that creates new anchors.
+		/// </summary>
+		public AnchorSegment(TextDocument document, int offset, int length)
+		{
+			if (document == null)
+				throw new ArgumentNullException("document");
+			this.start = document.CreateAnchor(offset);
+			this.start.SurviveDeletion = true;
+			this.start.MovementType = AnchorMovementType.AfterInsertion;
+			this.end = document.CreateAnchor(offset + length);
+			this.end.SurviveDeletion = true;
+			this.end.MovementType = AnchorMovementType.BeforeInsertion;
+		}
+		
+		/// <inheritdoc/>
+		public override string ToString()
+		{
+			return "[Offset=" + Offset.ToString(CultureInfo.InvariantCulture) + ", EndOffset=" + EndOffset.ToString(CultureInfo.InvariantCulture) + "]";
+		}
+	}
+}