Zip/Unzip of a file in Android

zip.kt

/**
 * Compress all the files for the backup into a .zip file
 * @param output A [FileOutputStream] where the zip file is going to be saved
 * @param input The files that are going to be compressed into the .zip file
 */
private fun zipFiles(output: FileOutputStream, vararg input: File?) {
    val zipOutput = ZipOutputStream(BufferedOutputStream(output))

    val addZipEntry = { file: File ->
        val entry = ZipEntry(file.name)
        val zipInput = BufferedInputStream(FileInputStream(file))
        zipOutput.putNextEntry(entry)
        zipInput.run {
            copyTo(zipOutput)
            close()
        }
        zipOutput.closeEntry()
    }

    try {
        input.forEach { file ->
            file?.let {
                if (!file.isDirectory) addZipEntry(file)
                else file.listFiles()?.forEach { file ->
                    if (file.extension == "jpg") addZipEntry(file)
                }
            }
        }
        zipOutput.close()
    } catch (e: IllegalArgumentException) {
        throw Exception()
    } catch (e: ZipException) {
        throw Exception()
    } catch (e: IOException) {
        throw Exception()
    }
}


/**
 * Decompresses the .zip file with the files for the restoration process into the Documents folder
 */
private fun unzipBackupFiles() {
    val input =
        ZipFile(backupDir?.path + "/recipe-vault-backup.zip")

    val entries: Enumeration<out ZipEntry?> = input.entries()
    while (entries.hasMoreElements()) {
        val entry = entries.nextElement()
        val output = entry?.run {
            if (name == "recipes_db")
                BufferedOutputStream(FileOutputStream(File(backupDir, name)))
            else
                BufferedOutputStream(FileOutputStream(File(photosDir, name)))
        }

        val data = input.getInputStream(entry)
        val bytes = data.readBytes()
        output?.write(bytes)
        data.close()
        output?.close()
    }
}