Zlib Inflate/Decompress in Kotlin

zlibDecompress.kt

/**
 * Zlib decompress a file and return its contents
 *
 * @param filePath absolute path to file
 * @return unzipped file contents
 */
fun decompress(filePath: String) : String {
    val content = File(filePath).readBytes()
    val inflater = Inflater()
    val outputStream = ByteArrayOutputStream()
    val buffer = ByteArray(1024)

    inflater.setInput(content)

    while (!inflater.finished()) {
        val count = inflater.inflate(buffer)
        outputStream.write(buffer, 0, count)
    }

    outputStream.close()

    return outputStream.toString(UTF_8)
}

This helped, thank you!

In my case inflater.finished() is never true so I do:

/**
 * Decompress a byte array using ZLIB.
 *
 * @return an UTF-8 encoded string.
 */
fun ByteArray.zlib(): String {
    val inflater = Inflater()
    val outputStream = ByteArrayOutputStream()

    return outputStream.use {
        val buffer = ByteArray(1024)

        inflater.setInput(this)

        var count = -1
        while (count != 0) {
            count = inflater.inflate(buffer)
            outputStream.write(buffer, 0, count)
        }

        inflater.end()
        outputStream.toString("UTF-8")
    }
}

On the Android platform at least, there's InflaterInputStream, allowing for nifty things like InflaterInputStream(inputBytes.inputStream()).bufferedReader().use { it.readText() }