@Override
public int nextAsInt() {
long t = w & -w;
int answer = (x + 1) * 64 - 1 - Long.bitCount(t - 1);
w ^= t;
while (w == 0) {
--x;
if (x < 0) break;
w = Long.reverse(bitmap[x]);
}
return answer;
}
void wrap(long[] b) {
bitmap = b;
for (x = bitmap.length - 1; x >= 0; --x) if ((w = Long.reverse(bitmap[x])) != 0) break;
}