knxultimate/src/protocol/cEMI/CEMIMessage.ts

KNX IP protocol implementation for Node. This is the ENGINE of Node-Red KNX-Ultimate node.

import KNXAddress from '../KNXAddress'
import KNXDataBuffer from '../KNXDataBuffer'
import ControlField from './ControlField'
import NPDU from './NPDU'

export default class CEMIMessage {
	msgCode: number

	length: number

	additionalInfo: KNXDataBuffer | null

	control: ControlField

	srcAddress: KNXAddress

	dstAddress: KNXAddress

	npdu: NPDU

	constructor(
		msgCode: number,
		length: number,
		additionalInfo?: KNXDataBuffer,
		control?: ControlField,
		srcAddress?: KNXAddress,
		dstAddress?: KNXAddress,
		npdu?: NPDU,
	) {
		this.msgCode = msgCode
		this.length = length
		this.additionalInfo = additionalInfo
		this.control = control
		this.srcAddress = srcAddress
		this.dstAddress = dstAddress
		this.npdu = npdu
	}

	toBuffer(): Buffer {
		const buffer = Buffer.alloc(2)
		buffer.writeUInt8(this.msgCode, 0)
		const len = this.additionalInfo == null ? 0 : this.additionalInfo.length
		buffer.writeUInt8(len, 1)
		if (this.additionalInfo) {
			return Buffer.concat([buffer, this.additionalInfo.value])
		}
		return buffer
	}

	static GetLength(
		additionalInfo: KNXDataBuffer | null,
		control: ControlField,
		srcAddress: KNXAddress,
		dstAddress: KNXAddress,
		npdu: NPDU,
	): number {
		const length = additionalInfo === null ? 1 : additionalInfo.length
		const npduLength = npdu == null ? 0 : npdu.length
		return (
			1 +
			length +
			control.length +
			srcAddress.length +
			dstAddress.length +
			npduLength
		)
	}
}