Bit-packed, zero-allocation serializer for tiny dense wire payloads, offering forward-only reader/writer API, inline typed results, lazy field reads, and in-place frame mutation.
Kompact is a Kotlin Multiplatform library for reading and writing compact, LSB-first bit-packed messages. Use the runtime directly for small fixed layouts, or generate typed views from schemas. The framed API adds strings, byte arrays, nested messages, and repeated fields with explicit length boundaries.
import ch.trancee.kompact.runtime.KompactRuntime
import ch.trancee.kompact.runtime.KompactWriter
import ch.trancee.kompact.runtime.ScalarType
val writer = KompactWriter()
writer.writeScalar(ScalarType.of(4, signed = false), 5L) // battery status
writer.writeScalar(ScalarType.of(10, signed = false), 10L) // speed
writer.writeBool(true) // malfunction flag
val bytes = writer.build() // [0xA5, 0x40]
val battery = KompactRuntime.readScalar(bytes, 0, ScalarType.of(4, signed = false)).getOrThrow()
val speed = KompactRuntime.readScalar(bytes, 4, ScalarType.of(10, signed = false)).getOrThrow()
val malfunction = KompactRuntime.readBool(bytes, 14).getOrThrow()The getting-started tutorial walks through this frame and shows the expected bytes and decoded values.
The latest Maven Central release is 0.8.0:
repositories {
mavenCentral()
}
dependencies {
implementation("ch.trancee.kompact:kompact:0.8.0")
}The current development version in this checkout is 0.8.0; it is
not published to Maven Central. To try unreleased changes, publish the snapshot
modules to Maven Local and follow the
consumer setup guide.
bitOffset and bitWidth when every field has a
stable position. Generated value-class views are described in
How to define a fixed-layout schema.order and length/count prefixes when a
message contains strings, byte arrays, nested messages, or repeated values.
See How to define a framed schema.Both forms use the same runtime writer and checked decode APIs. The architecture guide explains the wire format, borrowed data, and the tradeoffs between the two layouts.
| If you want to… | Start here |
|---|---|
| Build and decode your first frame | Getting started |
| Add Kompact to a Kotlin or KMP project | Consume Kompact |
| Define a fixed-layout model | Fixed-layout schema guide |
| Define a sequential framed model | Framed schema guide |
| Read or write strings, blobs, nested data, and repeats | Long-form payloads |
| Handle malformed input | Decode errors |
| Pass frames across a BLE boundary | BLE integration |
| Look up public signatures and behavior | API reference |
| Understand design decisions | Architecture |
| Contribute or run project checks | Contributing |
The generated, per-symbol API reference is also available in
kompact/docs/api/.
| Module | Purpose |
|---|---|
:kompact |
KMP runtime, annotations, and generated API documentation |
:kompact-ksp |
KSP processor for fixed-layout and framed schemas |
:kompact-gradle-plugin |
Common-source generation for supported KMP targets |
Kompact is released into the public domain. See LICENSE.
Kompact is a Kotlin Multiplatform library for reading and writing compact, LSB-first bit-packed messages. Use the runtime directly for small fixed layouts, or generate typed views from schemas. The framed API adds strings, byte arrays, nested messages, and repeated fields with explicit length boundaries.
import ch.trancee.kompact.runtime.KompactRuntime
import ch.trancee.kompact.runtime.KompactWriter
import ch.trancee.kompact.runtime.ScalarType
val writer = KompactWriter()
writer.writeScalar(ScalarType.of(4, signed = false), 5L) // battery status
writer.writeScalar(ScalarType.of(10, signed = false), 10L) // speed
writer.writeBool(true) // malfunction flag
val bytes = writer.build() // [0xA5, 0x40]
val battery = KompactRuntime.readScalar(bytes, 0, ScalarType.of(4, signed = false)).getOrThrow()
val speed = KompactRuntime.readScalar(bytes, 4, ScalarType.of(10, signed = false)).getOrThrow()
val malfunction = KompactRuntime.readBool(bytes, 14).getOrThrow()The getting-started tutorial walks through this frame and shows the expected bytes and decoded values.
The latest Maven Central release is 0.8.0:
repositories {
mavenCentral()
}
dependencies {
implementation("ch.trancee.kompact:kompact:0.8.0")
}The current development version in this checkout is 0.8.0; it is
not published to Maven Central. To try unreleased changes, publish the snapshot
modules to Maven Local and follow the
consumer setup guide.
bitOffset and bitWidth when every field has a
stable position. Generated value-class views are described in
How to define a fixed-layout schema.order and length/count prefixes when a
message contains strings, byte arrays, nested messages, or repeated values.
See How to define a framed schema.Both forms use the same runtime writer and checked decode APIs. The architecture guide explains the wire format, borrowed data, and the tradeoffs between the two layouts.
| If you want to… | Start here |
|---|---|
| Build and decode your first frame | Getting started |
| Add Kompact to a Kotlin or KMP project | Consume Kompact |
| Define a fixed-layout model | Fixed-layout schema guide |
| Define a sequential framed model | Framed schema guide |
| Read or write strings, blobs, nested data, and repeats | Long-form payloads |
| Handle malformed input | Decode errors |
| Pass frames across a BLE boundary | BLE integration |
| Look up public signatures and behavior | API reference |
| Understand design decisions | Architecture |
| Contribute or run project checks | Contributing |
The generated, per-symbol API reference is also available in
kompact/docs/api/.
| Module | Purpose |
|---|---|
:kompact |
KMP runtime, annotations, and generated API documentation |
:kompact-ksp |
KSP processor for fixed-layout and framed schemas |
:kompact-gradle-plugin |
Common-source generation for supported KMP targets |
Kompact is released into the public domain. See LICENSE.