public void decrement(int by) {
		// if given value is negative, we have to increment
		if (by < 0) {
			decrement(Math.abs(by));
			return;
		}

		// check if we would overflow
		int space_down = value - min;
		if (by > space_down) {
			// we simply use min
			value = min;
		} else {
			// no overflowing, this is easy
			value -= by;
		}
	}