floor or ceil power of 2

floor_ceil_power_2.cpp

inline constexpr uint32_t ceilPowerOfTwo(uint32_t num) {
    num |= (num >> 1);
    num |= (num >> 2);
    num |= (num >> 4);
    num |= (num >> 8);
    num |= (num >> 16);
    return num - (num >> 1);
}

inline constexpr uint32_t roundupPowerOfTwo(uint32_t num) {
    return ceilPowerOfTwo((num - 1) << 1);
}