Method Select

roaring.go:1351–1364

Select returns the xth integer in the bitmap. If you pass 0, you get the smallest element. Note that this function differs in convention from the Rank function which returns 1 on the smallest value.

(x uint32)

// the smallest element. Note that this function differs in convention from
// the Rank function which returns 1 on the smallest value.
func (rb *Bitmap) Select(x uint32) (uint32, error) {
	remaining := x
	for i := 0; i < rb.highlowcontainer.size(); i++ {
		c := rb.highlowcontainer.getContainerAtIndex(i)
		card := uint32(c.getCardinality())
		if remaining >= card {
			remaining -= card
		} else {
			key := rb.highlowcontainer.getKeyAtIndex(i)
			return uint32(key)<<16 + uint32(c.selectInt(uint16(remaining))), nil
		}
	}
	return 0, fmt.Errorf("cannot find %dth integer in a bitmap with only %d items", x, rb.GetCardinality())
}

// And computes the intersection between two bitmaps and stores the result in the current bitmap
func (rb *Bitmap) And(x2 *Bitmap) {