private void pushState(Node<K,V>[] t, int i, int n) {
            TableStack<K,V> s = spare;  // reuse if possible
            if (s != null)
                spare = s.next;
            else
                s = new TableStack<K,V>();
            s.tab = t;
            s.length = n;
            s.index = i;
            s.next = stack;
            stack = s;
        }
private void pushState(Node<K,V>[] t, int i, int n)