knxultimate/src/protocol/CRD.ts

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

/**
 * Represents KNX connection response data blocks.
 *
 * 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 { KNX_CONSTANTS } from './KNXConstants'
import KNXAddress from './KNXAddress'

const CRD_LENGTH: number = 4

export enum ConnectionType {
	TUNNEL_CONNECTION = KNX_CONSTANTS.TUNNEL_CONNECTION,
	DEVICE_MGMT_CONNECTION = KNX_CONSTANTS.DEVICE_MGMT_CONNECTION,
	REMLOG_CONNECTION = KNX_CONSTANTS.REMLOG_CONNECTION,
	REMCONF_CONNECTION = KNX_CONSTANTS.REMCONF_CONNECTION,
	OBJSVR_CONNECTION = KNX_CONSTANTS.OBJSVR_CONNECTION,
}

export default class CRD {
	private _connectionType: ConnectionType

	private _knxAddress: KNXAddress

	constructor(connectionType: ConnectionType, knxAddress: KNXAddress) {
		this._connectionType = connectionType
		this._knxAddress = knxAddress
	}

	set knxAddress(knxAddress: KNXAddress) {
		this._knxAddress = knxAddress
	}

	get knxAddress(): KNXAddress {
		return this._knxAddress
	}

	get length(): number {
		return CRD_LENGTH
	}

	set connectionType(connectionType: ConnectionType) {
		this._connectionType = connectionType
	}

	get connectionType(): ConnectionType {
		return this._connectionType
	}

	static createFromBuffer(buffer: Buffer, offset: number): CRD {
		if (offset >= buffer.length) {
			throw new Error('Buffer too short')
		}
		const structureLength: number = buffer.readUInt8(offset)
		if (offset + structureLength > buffer.length) {
			throw new Error('Buffer too short')
		}
		offset += 1
		const connectionType: ConnectionType = buffer.readUInt8(offset++)
		const knxAddress: number = buffer.readUInt16BE(offset)
		return new CRD(connectionType, KNXAddress.createFromString(knxAddress))
	}

	toBuffer(): Buffer {
		const buffer: Buffer = Buffer.alloc(this.length)
		let offset: number = 0
		buffer.writeUInt8(this.length, offset++)
		buffer.writeUInt8(this.connectionType, offset++)
		buffer.writeUInt16BE(this.knxAddress.get(), offset)
		return buffer
	}
}