Counting the number of flags set on an enumeration

Question

I\'m sure there must be a much better way of doing this. I\'m trying to do a count operation on a Flags enum. Before I was itterating over all the possible values and counting t

Answer 1

After looking on the site Assaf suggested I managed to find a slightly different solution that I got working for Int32's.

Here's the code for anyone else:

    internal static UInt32 Count(this Skills skills)
    {
        UInt32 v = (UInt32)skills;
        v = v - ((v >> 1) & 0x55555555); // reuse input as temporary
        v = (v & 0x33333333) + ((v >> 2) & 0x33333333); // temp
        UInt32 c = ((v + (v >> 4) & 0xF0F0F0F) * 0x1010101) >> 24; // count
        return c;
    }