public bool MoveNext()
{
switch (_status)
{
case DoublyLinkedListEnumeratorStatus.New:
{
_current = _first;
_status = GetStatusAfterMovingNext(_current);
return(_status == DoublyLinkedListEnumeratorStatus.HasValue);
}
case DoublyLinkedListEnumeratorStatus.HasValue:
{
_current = _current.Next;
_status = GetStatusAfterMovingNext(_current);
return(_status == DoublyLinkedListEnumeratorStatus.HasValue);
}
case DoublyLinkedListEnumeratorStatus.ReachedTheEnd:
return(false);
}
throw new InvalidOperationException("Unknown status");
}
public void Reset()
{
_current = null;
_status = DoublyLinkedListEnumeratorStatus.New;
}
private static DoublyLinkedListEnumeratorStatus GetStatusAfterMovingNext(DoublyLinkedListNode <T> current)
{
var hasNodes = current != null;
return(hasNodes ? DoublyLinkedListEnumeratorStatus.HasValue : DoublyLinkedListEnumeratorStatus.ReachedTheEnd);
}
public DoublyLinkedListEnumerator(DoublyLinkedListNode <T> first)
{
_first = first;
}
