knxultimate/src/protocol/KNXConnectionStateRequest.ts

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

/**
 * Builds KNX connection state request frames.
 *
 * Written in Italy with love, sun and passion, by Massimo Saccani.
 *
 * Released under the MIT License.
 * Use at your own risk; the author assumes no liability for damages.
 */

import KNXPacket from './KNXPacket'
import { KNX_CONSTANTS } from './KNXConstants'
import HPAI from './HPAI'

export default class KNXConnectionStateRequest extends KNXPacket {
	channelID: number

	hpaiControl: HPAI

	constructor(channelID: number, hpaiControl: HPAI | string = HPAI.NULLHPAI) {
		super(KNX_CONSTANTS.CONNECTIONSTATE_REQUEST, hpaiControl.length + 2)
		this.channelID = channelID
		this.hpaiControl =
			typeof hpaiControl === 'string'
				? new HPAI(hpaiControl)
				: hpaiControl
	}

	static createFromBuffer(
		buffer: Buffer,
		offset: number = 0,
	): KNXConnectionStateRequest {
		if (offset >= buffer.length) {
			throw new Error('Buffer too short')
		}
		const channelID = buffer.readUInt8(offset++)
		offset++
		const hpaiControl = HPAI.createFromBuffer(buffer, offset)
		return new KNXConnectionStateRequest(channelID, hpaiControl)
	}

	toBuffer(): Buffer {
		const buffer = Buffer.alloc(2)
		buffer.writeUInt8(this.channelID, 0)
		buffer.writeUInt8(0, 1)
		return Buffer.concat([
			this.header.toBuffer(),
			buffer,
			this.hpaiControl.toBuffer(),
		])
	}
}