return -1, errInvalidDecompressedSize
		}
		size, err := strconv.ParseInt(sizeStr, 10, 64)
		if err != nil {
			return -1, errInvalidDecompressedSize
		}
		return size, nil
	}
	if _, ok := crypto.IsEncrypted(o.UserDefined); ok {
		sizeStr, ok := o.UserDefined[ReservedMetadataPrefix+"actual-size"]
		if ok {
			size, err := strconv.ParseInt(sizeStr, 10, 64)
			if err != nil {
				return -1, errObjectTampered
			}