code: private void reset()
      {
          int count = 0;
          for (int i = 0; i < tableLength; i++)
          {
              long t = tableAt(i);
              count += Long.bitCount(t & ONE_MASK);
              tableAt(i, (t >>> 1) & RESET_MASK);
          }
          size = (size >>> 1) - (count >>> 2);
      }
docs: Reduces every counter by half of its original value.