https://graphics.stanford.edu/~seander/bithacks.html#CountBitsSetParallel
[code language=”java”]
int NumberOfSetBits(int i)
{
i = i – ((i >>> 1) & 0x55555555);
i = (i & 0x33333333) + ((i >>> 2) & 0x33333333);
return (((i + (i >>> 4)) & 0x0F0F0F0F) * 0x01010101) >>> 24;
}
[/code]