algorithm - Round to the nearest power of two

Question

Is there a one line expression (possibly boolean) to get the nearest 2^n number for a given integer?

Example: 5,6,7 must be 8.

Answer 1

Round up to the next higher power of two: see bit-twiddling hacks.

In C:

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++;