return err
						}

						splitData, err := rs.Split(m.mapped)
						if err != nil {
							return err
						}
						// Do separate encode, verify we get the same result.
						err = rs.Encode(splitData)
						if err != nil {
							return err
						}
						misMatches := 0
						for idx, sh := range parityData {
							calculated := splitData[idx]
							if !bytes.Equal(calculated, sh) {

		return -1
	}
	second := strings.Index(s[first+1:], substr)
	if second == -1 {
		return -1
	}
	return first + second + 1
}

// splitPath splits a path into a top-level directory and a child item. The
// parent directory retains the trailing slash.
func splitPath(s string, secondIndex bool) (string, string) {
	var i int
	if secondIndex {
		i = findSecondIndex(s, "/")
	} else {
		i = strings.Index(s, "/")
	}