static ceilLg2(n) {
        if (n <= 1) {
            return 0;
        }
        let p = Math.ceil(Math.log2(n));
        if (1<<p < n) {
            return p + 1;
        }
        if (n <= 1<<(p-1)) {
            return p - 1;
        }
        return p;
    }
@param {!int} n
@returns {!int} A value p such that 2**(p-1) < n <= 2**p.