Two days look HashMap source, which has a saw algorithm, when a programmer configured hashmap hashmap if the capacity of a given n-th power of 2 is not, this should give it greater than a minimum number and the n-th power of 2 . See the source code inside, suddenly feeling scared to Heaven. Very admire those engineers developed written language of the underlying database.
Maybe in the future work will encounter this demand:
1. | =: is the bitwise or assignment and meaning.
2 >>>: indicates unsigned binary number to the right moving, after moving in front of all 0s.
public int MIN_POWER_TWO(int cap) {
int n = cap - 1;
n |= n >>> 1;
n |= n >>> 2;
n |= n >>> 4;
n |= n >>> 8;
n |= n >>> 16;
return n + 1;
}