package roaring // bit population count, take from // https://code.google.com/p/go/issues/detail?id=4988#c11 // credit: https://code.google.com/u/arnehormann/ // credit: https://play.golang.org/p/U7SogJ7psJ // credit: http://graphics.stanford.edu/~seander/bithacks.html#CountBitsSetParallel func popcount(x uint64) uint64 { x -= (x >> 1) & 0x5555555555555555 x = (x>>2)&0x3333333333333333 + x&0x3333333333333333 x += x >> 4 x &= 0x0f0f0f0f0f0f0f0f x *= 0x0101010101010101 return x >> 56 } func popcntSliceGo(s []uint64) uint64 { cnt := uint64(0) for _, x := range s { cnt += popcount(x) } return cnt } func popcntMaskSliceGo(s, m []uint64) uint64 { cnt := uint64(0) for i := range s { cnt += popcount(s[i] &^ m[i]) } return cnt } func popcntAndSliceGo(s, m []uint64) uint64 { cnt := uint64(0) for i := range s { cnt += popcount(s[i] & m[i]) } return cnt } func popcntOrSliceGo(s, m []uint64) uint64 { cnt := uint64(0) for i := range s { cnt += popcount(s[i] | m[i]) } return cnt } func popcntXorSliceGo(s, m []uint64) uint64 { cnt := uint64(0) for i := range s { cnt += popcount(s[i] ^ m[i]) } return cnt }