func getOpts(ctx context.Context, r *http.Request, bucket, object string) (ObjectOptions, error) {
	var opts ObjectOptions

	var partNumber int
	var err error
	if pn := r.Form.Get(xhttp.PartNumber); pn != "" {
		partNumber, err = strconv.Atoi(pn)
		if err != nil {
			return opts, err
		}
		if isMaxPartID(partNumber) {
			return opts, errInvalidMaxParts
		}
		if partNumber <= 0 {
			return opts, errInvalidArgument