defer closer.Close()
			}
			reader = r
		}

		var magics string
		magics, err = readMagic(reader)
		if err != nil {
			return
		}

		if magics == archiveMagic || magics == aixbigafMagic {
			reader, err = arExportData(reader)
			if err != nil {
				return
			}
			magics, err = readMagic(reader)
			if err != nil {
				return
			}
		}

		switch magics {