Gzip compression and decompression in Kotlin / Android

gzip.kt

import java.io.ByteArrayInputStream
import java.io.ByteArrayOutputStream
import java.util.zip.GZIPInputStream
import java.util.zip.GZIPOutputStream

/**
 * Compress a string using GZIP.
 *
 * @return an UTF-8 encoded byte array.
 */
fun String.gzipCompress(): ByteArray {
    val bos = ByteArrayOutputStream()
    GZIPOutputStream(bos).bufferedWriter(Charsets.UTF_8).use { it.write(this) }
    return bos.toByteArray()
}

/**
 * Decompress a byte array using GZIP.
 *
 * @return an UTF-8 encoded string.
 */
fun ByteArray.gzipDecompress(): String {
    val bais = ByteArrayInputStream(this)
    lateinit var string: String
    GZIPInputStream(bais).bufferedReader(Charsets.UTF_8).use { return it.readText() }
}

if someone needs fewer lines:
fun ByteArray.gzipDecompress(): String = GZIPInputStream(this.inputStream()).bufferedReader(Charsets.UTF_8).use { return it.readText() }

@WildFlames .use { return it.readText() } don't do return here as it would cause to return from the ByteArray.gzipDecompress() instead of use

    GZIPInputStream(bais).bufferedReader(Charsets.UTF_8).use { return it.readText() }

…can be…

    return GZIPInputStream(bais).bufferedReader(Charsets.UTF_8).use { it.readText() }