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/**
* The iAm event represents the response to a whoIs request to detect all
* devices in a BACNET network.
*
* @event bacnet.iAm
* @param {number} deviceId - The BACNET device-id of the detected device.
* @param {number} maxApdu - The max APDU size the detected device supports.
* @param {number} segmentation - The type of segmentation the detected device supports.
* @param {number} vendorId - The BACNET vendor-id of the detected device.
*
* @example
* const bacnet = require('node-bacnet');
* const client = new bacnet();
*
* client.on('iAm', (msg) => {
* console.log(
* 'address: ', msg.header.address,
* ' - deviceId: ', msg.payload.deviceId,
* ' - maxApdu: ', msg.payload.maxApdu,
* ' - segmentation: ', msg.payload.segmentation,
* ' - vendorId: ', msg.payload.vendorId
* );
* });
*/
'use strict';
const baAsn1 = require('../asn1');
const baEnum = require('../enum');
module.exports.encode = (buffer, deviceId, maxApdu, segmentation, vendorId) => {
baAsn1.encodeApplicationObjectId(buffer, baEnum.ObjectType.DEVICE, deviceId);
baAsn1.encodeApplicationUnsigned(buffer, maxApdu);
baAsn1.encodeApplicationEnumerated(buffer, segmentation);
baAsn1.encodeApplicationUnsigned(buffer, vendorId);
};
module.exports.decode = (buffer, offset) => {
let result;
let apduLen = 0;
const orgOffset = offset;
result = baAsn1.decodeTagNumberAndValue(buffer, offset + apduLen);
apduLen += result.len;
if (result.tagNumber !== baEnum.ApplicationTags.OBJECTIDENTIFIER) return;
result = baAsn1.decodeObjectId(buffer, offset + apduLen);
apduLen += result.len;
if (result.objectType !== baEnum.ObjectType.DEVICE) return;
const deviceId = result.instance;
result = baAsn1.decodeTagNumberAndValue(buffer, offset + apduLen);
apduLen += result.len;
if (result.tagNumber !== baEnum.ApplicationTags.UNSIGNED_INTEGER) return;
result = baAsn1.decodeUnsigned(buffer, offset + apduLen, result.value);
apduLen += result.len;
const maxApdu = result.value;
result = baAsn1.decodeTagNumberAndValue(buffer, offset + apduLen);
apduLen += result.len;
if (result.tagNumber !== baEnum.ApplicationTags.ENUMERATED) return;
result = baAsn1.decodeEnumerated(buffer, offset + apduLen, result.value);
apduLen += result.len;
if (result.value > baEnum.Segmentation.NO_SEGMENTATION) return;
const segmentation = result.value;
result = baAsn1.decodeTagNumberAndValue(buffer, offset + apduLen);
apduLen += result.len;
if (result.tagNumber !== baEnum.ApplicationTags.UNSIGNED_INTEGER) return;
result = baAsn1.decodeUnsigned(buffer, offset + apduLen, result.value);
apduLen += result.len;
if (result.value > 0xFFFF) return;
const vendorId = result.value;
return {
len: offset - orgOffset,
deviceId: deviceId,
maxApdu: maxApdu,
segmentation: segmentation,
vendorId: vendorId
};
};