value power two

 /**
 *topPower2 use to set unsigned int to power of two
 *@param value input value
 *@return return the value's of the value,if input 3 return 4, if input 4 return 4
 */
 size_t topPower2(size_t value){
     if((value & (value-)) == ){
         return value;
     }
     unsigned long max_ulong = (unsigned long)((unsigned long)~);
     unsigned long mid = ~(max_ulong&(max_ulong>>));
     while((mid & value) == ){
         mid = mid>>;
     }
     return mid<<;
 }