From c001357617c2b59d08534f9532e8bdb6bd780893 Mon Sep 17 00:00:00 2001
From: Daniel Grunwald <daniel@danielgrunwald.de>
Date: Tue, 20 Sep 2011 02:46:32 +0200
Subject: [PATCH] Add GetNewOffset() method to TextChangeEventArgs.

---
 .../Editor/ITextAnchor.cs                       |  4 ++--
 .../Editor/TextChangeEventArgs.cs               | 17 +++++++++++++++++
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/src/Libraries/NRefactory/ICSharpCode.NRefactory/Editor/ITextAnchor.cs b/src/Libraries/NRefactory/ICSharpCode.NRefactory/Editor/ITextAnchor.cs
index 6020ddc8dd..be1f084eec 100644
--- a/src/Libraries/NRefactory/ICSharpCode.NRefactory/Editor/ITextAnchor.cs
+++ b/src/Libraries/NRefactory/ICSharpCode.NRefactory/Editor/ITextAnchor.cs
@@ -121,8 +121,8 @@ namespace ICSharpCode.NRefactory.Editor
 	{
 		/// <summary>
 		/// When text is inserted at the anchor position, the type of the insertion
-		/// determines where the caret moves to. For normal insertions, the anchor will stay
-		/// behind the inserted text.
+		/// determines where the caret moves to. For normal insertions, the anchor will move
+		/// after the inserted text.
 		/// </summary>
 		Default,
 		/// <summary>
diff --git a/src/Libraries/NRefactory/ICSharpCode.NRefactory/Editor/TextChangeEventArgs.cs b/src/Libraries/NRefactory/ICSharpCode.NRefactory/Editor/TextChangeEventArgs.cs
index a0c0f659ee..e97b12de66 100644
--- a/src/Libraries/NRefactory/ICSharpCode.NRefactory/Editor/TextChangeEventArgs.cs
+++ b/src/Libraries/NRefactory/ICSharpCode.NRefactory/Editor/TextChangeEventArgs.cs
@@ -75,5 +75,22 @@ namespace ICSharpCode.NRefactory.Editor
 			this.removedText = removedText ?? string.Empty;
 			this.insertedText = insertedText ?? string.Empty;
 		}
+		
+		/// <summary>
+		/// Gets the new offset where the specified offset moves after this document change.
+		/// </summary>
+		public virtual int GetNewOffset(int offset, AnchorMovementType movementType = AnchorMovementType.Default)
+		{
+			if (offset >= this.Offset && offset <= this.Offset + this.RemovalLength) {
+				if (movementType == AnchorMovementType.BeforeInsertion)
+					return this.Offset;
+				else
+					return this.Offset + this.InsertionLength;
+			} else if (offset > this.Offset) {
+				return offset + this.InsertionLength - this.RemovalLength;
+			} else {
+				return offset;
+			}
+		}
 	}
 }