func (x *Index) Bytes() []byte {
	return x.data
}

func (x *Index) at(i int) []byte {
	return x.data[x.sa.get(i):]
}

// lookupAll returns a slice into the matching region of the index.
// The runtime is O(log(N)*len(s)).
func (x *Index) lookupAll(s []byte) ints {
	// find matching suffix index range [i:j]
	// find the first index where s would be the prefix