code: public static long nextPowerOfTwo(long x) {
  		if (x == 0L) {
  			return 1L;
  		} else {
  			--x;
  			x |= x >> 1;
  			x |= x >> 2;
  			x |= x >> 4;
  			x |= x >> 8;
  			x |= x >> 16;
  			return (x | x >> 32) + 1L;
  		}
  	}
docs: Return the least power of two greater than or equal to the specified value.
  
  <p>Note that this function will return 1 when the argument is 0.
  
  @param x a long integer smaller than or equal to 2<sup>62</sup>.
  @return the least power of two greater than or equal to the specified value.