public UndoBuffer(int i)
{
BuffSize = i;
_nElem = 0; // pocitadlo elementu v bufferu
bottom = null;
top = null;
current = null;
atBottom = true;
}
public object Undo()
{
if (current != null)
{
object obj = current.elem;
if (current.prev != null)
{
current = current.prev;
_nElem--;
atBottom = false;
}
else
{
atBottom = true;
}
return(obj);
}
return(null);
}
public void Add2Buff(object o)
{
if (o != null)
{
BufferedObject g = new BufferedObject(o);
if (Get_nElem == 0)
{
g.next = null;
g.prev = null;
top = g;
bottom = g;
current = g;
}
else
{
g.prev = current;
g.next = null;
current.next = g;
top = g;
current = g;
if (Get_nElem == 1)
{
bottom.next = g;
}
}
_nElem++;
if (BuffSize < Get_nElem)
{
bottom = bottom.next;
bottom.prev = null;
_nElem--;
}
atBottom = false;
}
}
public object Redo()
{
if (current != null)
{
object obj;
if (!atBottom)
{
if (current.next != null)
{
current = current.next;
_nElem++;
}
}
else
{
atBottom = false;
}
obj = current.elem;
return(obj);
}
//this._N_elem = count();
return(null);
}