1 files changed, 38 insertions, 11 deletions

diff --git a/src/CellBuffer.h b/src/CellBuffer.h
index 5fbe2ea8a..6e052077e 100644
--- a/src/CellBuffer.h
+++ b/src/CellBuffer.h
@@ -89,6 +89,42 @@ public:
 
 enum undoCollectionType { undoCollectNone, undoCollectAutoStart, undoCollectManualStart };
 
+class UndoHistory {
+	Action *actions;
+	int lenActions;
+	int maxAction;
+	int currentAction;
+	int undoSequenceDepth;
+	int savePoint;
+
+	void EnsureUndoRoom();
+	
+public:
+	UndoHistory();
+	~UndoHistory();
+	
+	void AppendAction(actionType at, int position, char *data, int length);
+
+	void BeginUndoAction();
+	void EndUndoAction();
+	void DropUndoSequence();
+	void DeleteUndoHistory();
+	
+	// The save point is a marker in the undo stack where the container has stated that 
+	// the buffer was saved. Undo and redo can move over the save point.
+	void SetSavePoint();
+	bool IsSavePoint() const;
+
+	// To perform an undo, StartUndo is called to retrieve the number of steps, then UndoStep is 
+	// called that many times. Similarly for redo.
+	bool CanUndo() const;
+	int StartUndo();
+	const Action &UndoStep();
+	bool CanRedo() const;
+	int StartRedo();
+	const Action &RedoStep();
+};
+
 // Holder for an expandable array of characters that supports undo and line markers
 // Based on article "Data Structures in a Bit-Mapped Text Editor"
 // by Wilfred J. Hansen, Byte January 1987, page 183
@@ -102,13 +138,8 @@ private:
 	char *part2body;
 	bool readOnly;
 
-	Action *actions;
-	int lenActions;
-	int maxAction;
-	int currentAction;
 	undoCollectionType collectingUndo;
-	int undoSequenceDepth;
-	int savePoint;
+	UndoHistory uh;
 
 	LineVector lv;
 
@@ -117,9 +148,6 @@ private:
 	void GapTo(int position);
 	void RoomFor(int insertionLength);
 
-	void EnsureUndoRoom();
-	void AppendAction(actionType at, int position, char *data, int length);
-
 	inline char ByteAt(int position);
 	void SetByteAt(int position, char ch);
 
@@ -170,12 +198,11 @@ public:
 
 	undoCollectionType SetUndoCollection(undoCollectionType collectUndo);
 	bool IsCollectingUndo();
-	void AppendUndoStartAction();
 	void BeginUndoAction();
 	void EndUndoAction();
 	void DeleteUndoHistory();
 	
-	// To perform an undo, StartUndo is called to retreive the number of steps, then UndoStep is 
+	// To perform an undo, StartUndo is called to retrieve the number of steps, then UndoStep is 
 	// called that many times. Similarly for redo.
 	bool CanUndo();
 	int StartUndo();