private ForestNode <E> Next()
{
if (_current == null)
{
_current = _root.NewEdge(ForestNode <E> .Edge.Leading);
return(_current);
}
if (_current.CurrentEdge == ForestNode <E> .Edge.Leading)
{
if (_current.ChildCount == 0)
{
_current = _current.NewEdge(ForestNode <E> .Edge.Trailing);
return(_current);
}
_current = _current.Child(ForestNode <E> .Edge.Leading, 0);
return(_current);
}
ForestNode <E> parent = _current.Parent(ForestNode <E> .Edge.Trailing);
if (parent == null)
{
throw new Exception("No next node, never reached here");
}
int curIndex = _current.ChildIndex;
if (curIndex == -1)
{
throw new Exception("orphan node, invalid");
}
if (curIndex < parent.ChildCount - 1)
{
_current = parent.Child(ForestNode <E> .Edge.Leading, curIndex + 1);
return(_current);
}
// last sibling, go up ward.
_current = parent;
return(_current);
}
public void SkipChildren()
{
_current = _current.NewEdge(ForestNode <E> .Edge.Trailing);
}