KOTLink

KOTLink is an open-source MAVLink library developed in Kotlin. The project is structured in several modules and aims to make MAVLink communication seamless and efficient for Kotlin developers. It provides a handy interface to work with MAVLink protocols, parse MAVLink messages, and even auto-generate Kotlin data classes from MAVLink XML definitions.

Declaring dependencies

// The core of the library
implementation("com.mmoczkowski:kotlink-core:1.0.0")

// KTX extensions
implementation("com.mmoczkowski:kotlink-ktx:1.0.0")

// MAVLink Minimal protocol implementation
implementation("com.mmoczkowski:kotlink-protocol-minimal:1.0.0")

// MAVLink Common protocol implementation
implementation("com.mmoczkowski:kotlink-protocol-common:1.0.0")

// MAVLink ArduPilot Mega protocol implementation
implementation("com.mmoczkowski:kotlink-protocol-ardupilotmega:1.0.0")

// MAVLink code generation processor (only if you need to generate a protocol)
implementation("com.mmoczkowski:kotlink-processor:1.0.0")

Sample Usage

Utilize the MavLinkParser class as demonstrated:

val parser = MavLinkParser(MinimalMavlinkProtocol, CommonMavLinkProtocol)
val bytes = ... // your data
val frames = parser.parseNextBytes(bytes)
frames.forEach { frame ->
    when (frame) {
        is MavLinkFrame.V1 -> // handle MavLink v1 frame
        is MavLinkFrame.V2 -> // handle MavLink v2 frame
    }
}

The Kotlin Flow extension mapToMavLink can be applied as follows:

val flow: Flow<Byte> = ...
val mavlinkFlow = flow.mapToMavLink(MinimalMavlinkProtocol, CommonMavLinkProtocol)
mavlinkFlow.collect { frame ->
    when (frame) {
        is MavLinkFrame.V1 -> // handle MavLink v1 frame
        is MavLinkFrame.V2 -> // handle MavLink v2 frame
    }
}

Project Structure

The project is organized into the following modules:

• :core
• :processor
• :protocol:minimal
• :protocol:common
• :protocol:ardupilotmega
• :ktx

:core

The :core module forms the backbone of KOTLink, providing essential MAVLink classes and interfaces, including:

• MavLinkFrame: This sealed class symbolizes a parsed MAVLink frame, containing two subclasses for V1 and V2 MAVLink versions.
• MavLinkMessage: A representative interface for a MAVLink message, encapsulating the function toBytes(): ByteArray for serialization of the message into a raw payload.
• MavLinkProtocol: This interface depicts a MAVLink subset, furnished with methods fromBytes(messageId: UInt, payload: ByteArray): MavLinkMessage? and getCrcExtra(messageId: UInt): Byte?.
• MavLinkParser: This class, essential for parsing sequences of bytes into a MavLinkFrame containing a MavLinkMessage, uses the provided MAVLink XML definitions for parsing.

:processor

The :processor module serves as a KSP compiler plugin, translating MAVLink XML definitions into generated Kotlin data classes that inherit from the MavLinkMessage interface.

:protocol

The :protocol module is further divided into three submodules - :common, :minimal, and :ardupilotmega. These modules consist of MAVLink classes auto-generated from their respective XML files: common.xml, minimal.xml, and ardupilotmega.xml.

:ktx

The :ktx module adds functionality to the parser by offering Kotlin Flow extensions.