KFlate

KFlate is a Kotlin Multiplatform port of the npm fflate library. It provides pure Kotlin DEFLATE, GZIP, and ZLIB compression and decompression with configurable options and dictionary support.

Features

• Pure Kotlin implementation (no native dependencies)
• Raw DEFLATE compress/inflate
• GZIP and ZLIB wrappers
• Optional GZIP header fields (filename, comment, extra fields, header CRC)
• Dictionary support for DEFLATE/ZLIB
• Kotlin Multiplatform targets: JVM, Android, JS (Browser/Node), WASM, iOS

Installation

Kotlin Multiplatform (commonMain):

kotlin {
    sourceSets {
        val commonMain by getting {
            dependencies {
                implementation("com.rafambn:KFlate:0.1.0")
            }
        }
    }
}

JVM or Android (if you prefer platform-specific source sets):

dependencies {
    implementation("com.rafambn:KFlate:0.1.0")
}

Usage

Raw DEFLATE

import com.rafambn.kflate.KFlate
import com.rafambn.kflate.RAW
import com.rafambn.kflate.Raw

val input = "hello".encodeToByteArray()

val deflated = KFlate.compress(input, RAW())
val inflated = KFlate.decompress(deflated, Raw())

GZIP

import com.rafambn.kflate.KFlate
import com.rafambn.kflate.GZIP
import com.rafambn.kflate.Gzip

val input = "hello".encodeToByteArray()

val options = GZIP(
    filename = "hello.txt",
    comment = "example",
    extraFields = mapOf("AB" to byteArrayOf(1, 2)),
    includeHeaderCrc = true
)

val gz = KFlate.compress(input, options)
val roundTrip = KFlate.decompress(gz, Gzip())

ZLIB

import com.rafambn.kflate.KFlate
import com.rafambn.kflate.ZLIB
import com.rafambn.kflate.Zlib

val input = "hello".encodeToByteArray()

val z = KFlate.compress(input, ZLIB())
val out = KFlate.decompress(z, Zlib())

// With a preset dictionary
val dict = "common".encodeToByteArray()
val options = ZLIB(dictionary = dict)
val zWithDict = KFlate.compress(input, options)

Options

• CompressionType (RAW, GZIP, ZLIB)
  • level: 0..9 compression level
  • bufferSize: optional internal buffer size (for hash table)
  • dictionary: optional preset dictionary (max 32 KB)
  • GZIP specific: filename, comment, extraFields, mtime, includeHeaderCrc
• DecompressionType (Raw, Gzip, Zlib)
  • All support optional dictionary (max 32 KB)

Project Notes

• API uses standard ByteArray for binary data.
• This project focuses on compatibility with standard gzip/zlib tools and the DEFLATE spec.