if s == nil {
		return 0, -1, nil
	}
	err = s.Validate()
	if err != nil {
		return 0, 0, err
	}

	if s.End == nil && s.Start == nil {
		// Not valid, but should be caught above.
		return 0, -1, nil
	}
	if s.End == nil {
		start := int64(*s.Start)
		if start < 0 {
			return 0, 0, errors.New("ScanRange: Start after EOF")
		}
		return start, -1, nil
	}