@widesky/node-bacstack/lib/services/subscribe-property.js

The BACnet protocol library written in pure JavaScript.

'use strict';

const baAsn1      = require('../asn1');
const baEnum      = require('../enum');

module.exports.encode = (buffer, subscriberProcessId, monitoredObjectId, cancellationRequest, issueConfirmedNotifications, lifetime, monitoredProperty, covIncrementPresent, covIncrement) => {
  baAsn1.encodeContextUnsigned(buffer, 0, subscriberProcessId);
  baAsn1.encodeContextObjectId(buffer, 1, monitoredObjectId.type, monitoredObjectId.instance);
  if (!cancellationRequest) {
    baAsn1.encodeContextBoolean(buffer, 2, issueConfirmedNotifications);
    baAsn1.encodeContextUnsigned(buffer, 3, lifetime);
  }
  baAsn1.encodeOpeningTag(buffer, 4);
  baAsn1.encodeContextEnumerated(buffer, 0, monitoredProperty.id);
  if (monitoredProperty.index !== baEnum.ASN1_ARRAY_ALL) {
    baAsn1.encodeContextUnsigned(buffer, 1, monitoredProperty.index);
  }
  baAsn1.encodeClosingTag(buffer, 4);
  if (covIncrementPresent) {
    baAsn1.encodeContextReal(buffer, 5, covIncrement);
  }
};

module.exports.decode = (buffer, offset) => {
  let len = 0;
  let value = {};
  let result;
  let decodedValue;
  if (!baAsn1.decodeIsContextTag(buffer, offset + len, 0)) {
    return undefined;
  }
  result = baAsn1.decodeTagNumberAndValue(buffer, offset + len);
  len += result.len;
  decodedValue = baAsn1.decodeUnsigned(buffer, offset + len, result.value);
  len += decodedValue.len;
  value.subscriberProcessId = decodedValue.value;
  if (!baAsn1.decodeIsContextTag(buffer, offset + len, 1)) {
    return undefined;
  }
  result = baAsn1.decodeTagNumberAndValue(buffer, offset + len);
  len += result.len;
  decodedValue = baAsn1.decodeObjectId(buffer, offset + len);
  len += decodedValue.len;
  value.monitoredObjectId = {type: decodedValue.objectType, instance: decodedValue.instance};
  value.cancellationRequest = true;
  value.issueConfirmedNotifications = false;
  if (baAsn1.decodeIsContextTag(buffer, offset + len, 2)) {
    value.cancellationRequest = false;
    result = baAsn1.decodeTagNumberAndValue(buffer, offset + len);
    len += result.len;
    value.issueConfirmedNotifications = buffer[offset + len] > 0;
    len++;
  }
  value.lifetime = 0;
  if (baAsn1.decodeIsContextTag(buffer, offset + len, 3)) {
    result = baAsn1.decodeTagNumberAndValue(buffer, offset + len);
    len += result.len;
    decodedValue = baAsn1.decodeUnsigned(buffer, offset + len, result.value);
    len += decodedValue.len;
    value.lifetime = decodedValue.value;
  }
  if (!baAsn1.decodeIsOpeningTagNumber(buffer, offset + len, 4)) {
    return undefined;
  }
  len++;
  value.monitoredProperty = {};
  if (!baAsn1.decodeIsContextTag(buffer, offset + len, 0)) {
    return undefined;
  }
  result = baAsn1.decodeTagNumberAndValue(buffer, offset + len);
  len += result.len;
  decodedValue = baAsn1.decodeEnumerated(buffer, offset + len, result.value);
  len += decodedValue.len;
  value.monitoredProperty.id = decodedValue.value;
  value.monitoredProperty.index = baEnum.ASN1_ARRAY_ALL;
  if (baAsn1.decodeIsContextTag(buffer, offset + len, 1)) {
    result = baAsn1.decodeTagNumberAndValue(buffer, offset + len);
    len += result.len;
    decodedValue = baAsn1.decodeUnsigned(buffer, offset + len, result.value);
    len += decodedValue.len;
    value.monitoredProperty.index = decodedValue.value;
  }
  if (!baAsn1.decodeIsClosingTagNumber(buffer, offset + len, 4)) {
    return undefined;
  }
  len++;
  value.covIncrement = 0;
  if (baAsn1.decodeIsContextTag(buffer, offset + len, 5)) {
    result = baAsn1.decodeTagNumberAndValue(buffer, offset + len);
    len += result.len;
    decodedValue = baAsn1.decodeReal(buffer, offset + len);
    len += decodedValue.len;
    value.covIncrement = decodedValue.value;
  }
  value.len = len;
  return value;
};