这个位操作函数做什么？

Question

unsigned long ccNextPOT(unsigned long x){ 

    x = x - 1; 
    x = x | (x >> 1); 
    x = x | (x >> 2); 
    x = x | (x >> 4); 
    x = x | (x >> 8); 
    x = x | (x >>16); 
    return x + 1; 
} 

Answer 1

OR和SHIFT语句在最高有效位（最多32位）的右侧填充了x的所有位。连同前递减和递增后的语句，这个函数计算（作为函数名称suggets）下一个幂次数，等于或大于给定数字（如果x大于0且小于2^32 ）

Answer 2

此功能x舍高达2下一个最高权力这正是代码中here

unsigned int v; // compute the next highest power of 2 of 32-bit v 

v--; 
v |= v >> 1; 
v |= v >> 2; 
v |= v >> 4; 
v |= v >> 8; 
v |= v >> 16; 
v++;