/// <summary>
/// Adds item to the buffer
/// </summary>
/// <param name="item">Item to be added</param>
public void AddItem(T item)
{
if (item == null)
{
return;
}
UndoBufferNode <T> element = new UndoBufferNode <T>(item);
if (this.count == 0)
{
start = current = element;
}
else
{
element.Prev = current;
current.Next = element;
current = element;
if (this.count == 1)
{
start.Next = current;
}
}
this.count++;
if (this.bufferSize < this.count)
{
this.start = this.start.Next;
this.start.Prev = null;
this.count--;
}
isAtBottom = false;
}
/// <summary>
/// Resets(cleans) buffer
/// </summary>
public void ResetBuffer()
{
this.count = 0;
this.isAtBottom = true;
this.start = null;
this.current = null;
}
/// <summary>
/// Redo
/// </summary>
/// <returns>Redo object</returns>
public T Redo()
{
if (current == null)
{
return(null);
}
if (!isAtBottom)
{
if (current.Next != null)
{
current = current.Next;
this.count++;
}
}
else
{
isAtBottom = false;
}
return(current.Element);
}
/// <summary>
/// Undo last element on buffer
/// </summary>
/// <returns>undo object</returns>
public T Undo()
{
if (current == null)
{
return(null);
}
T undoObj = current.Element;
if (current.Prev != null)
{
current = current.Prev;
this.count--;
this.isAtBottom = false;
}
else
{
this.isAtBottom = true;
}
return(undoObj);
}