/* Round up to nearest power of two */
        size -= 1;
#define clp2shift(x,num) ((x) >> num)
        size |= clp2shift(size, 1);
        size |= clp2shift(size, 2);
        size |= clp2shift(size, 4);
        size |= clp2shift(size, 8);
        size |= clp2shift(size, 16);
        size += 1;
#undef clp2shift