case offsetEnd > -1:
		if offsetEnd == 0 {
			return nil, errInvalidRange
		}
		return &HTTPRangeSpec{true, -offsetEnd, -1}, nil
	default:
		// rangeString contains first and last byte positions missing. eg. "bytes=-"
		return nil, fmt.Errorf("'%s' does not have valid range value", rangeString)
	}
}

// String returns stringified representation of range for a particular resource size.