ICSharpCode.AvalonEdit.Document.TextDocument.DoReplace C# (CSharp) Method

        void DoReplace(int offset, int length, ITextSource newText, OffsetChangeMap offsetChangeMap)
        {
            if (length == 0 && newText.TextLength == 0)
                return;

            // trying to replace a single character in 'Normal' mode?
            // for single characters, 'CharacterReplace' mode is equivalent, but more performant
            // (we don't have to touch the anchorTree at all in 'CharacterReplace' mode)
            if (length == 1 && newText.TextLength == 1 && offsetChangeMap == null)
                offsetChangeMap = OffsetChangeMap.Empty;

            ITextSource removedText;
            if (length == 0) {
                removedText = StringTextSource.Empty;
            } else if (length < 100) {
                removedText = new StringTextSource(rope.ToString(offset, length));
            } else {
                // use a rope if the removed string is long
                removedText = new RopeTextSource(rope.GetRange(offset, length));
            }
            DocumentChangeEventArgs args = new DocumentChangeEventArgs(offset, removedText, newText, offsetChangeMap);

            // fire DocumentChanging event
            if (Changing != null)
                Changing(this, args);
            if (textChanging != null)
                textChanging(this, args);

            undoStack.Push(this, args);

            cachedText = null; // reset cache of complete document text
            fireTextChanged = true;
            DelayedEvents delayedEvents = new DelayedEvents();

            lock (lockObject) {
                // create linked list of checkpoints
                versionProvider.AppendChange(args);

                // now update the textBuffer and lineTree
                if (offset == 0 && length == rope.Length) {
                    // optimize replacing the whole document
                    rope.Clear();
                    var newRopeTextSource = newText as RopeTextSource;
                    if (newRopeTextSource != null)
                        rope.InsertRange(0, newRopeTextSource.GetRope());
                    else
                        rope.InsertText(0, newText.Text);
                    lineManager.Rebuild();
                } else {
                    rope.RemoveRange(offset, length);
                    lineManager.Remove(offset, length);
                    #if DEBUG
                    lineTree.CheckProperties();
                    #endif
                    var newRopeTextSource = newText as RopeTextSource;
                    if (newRopeTextSource != null)
                        rope.InsertRange(offset, newRopeTextSource.GetRope());
                    else
                        rope.InsertText(offset, newText.Text);
                    lineManager.Insert(offset, newText);
                    #if DEBUG
                    lineTree.CheckProperties();
                    #endif
                }
            }

            // update text anchors
            if (offsetChangeMap == null) {
                anchorTree.HandleTextChange(args.CreateSingleChangeMapEntry(), delayedEvents);
            } else {
                foreach (OffsetChangeMapEntry entry in offsetChangeMap) {
                    anchorTree.HandleTextChange(entry, delayedEvents);
                }
            }

            lineManager.ChangeComplete(args);

            // raise delayed events after our data structures are consistent again
            delayedEvents.RaiseEvents();

            // fire DocumentChanged event
            if (Changed != null)
                Changed(this, args);
            if (textChanged != null)
                textChanged(this, args);
        }