bacstack/lib/services/device-communication-control.js

A BACnet protocol stack written in pure JavaScript.

'use strict';

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

module.exports.encode = (buffer, timeDuration, enableDisable, password) => {
  if (timeDuration > 0) {
    baAsn1.encodeContextUnsigned(buffer, 0, timeDuration);
  }
  baAsn1.encodeContextEnumerated(buffer, 1, enableDisable);
  if (password && password !== '') {
    baAsn1.encodeContextCharacterString(buffer, 2, password);
  }
};

module.exports.decode = (buffer, offset, apduLen) => {
  let len = 0;
  const value = {};
  let decodedValue;
  let result;
  if (baAsn1.decodeIsContextTag(buffer, offset + len, 0)) {
    result = baAsn1.decodeTagNumberAndValue(buffer, offset + len);
    len += result.len;
    decodedValue = baAsn1.decodeUnsigned(buffer, offset + len, result.value);
    value.timeDuration = decodedValue.value;
    len += decodedValue.len;
  }
  if (!baAsn1.decodeIsContextTag(buffer, offset + len, 1)) return;
  result = baAsn1.decodeTagNumberAndValue(buffer, offset + len);
  len += result.len;
  decodedValue = baAsn1.decodeEnumerated(buffer, offset + len, result.value);
  value.enableDisable = decodedValue.value;
  len += decodedValue.len;
  if (len < apduLen) {
    if (!baAsn1.decodeIsContextTag(buffer, offset + len, 2)) return;
    result = baAsn1.decodeTagNumberAndValue(buffer, offset + len);
    len += result.len;
    decodedValue = baAsn1.decodeCharacterString(buffer, offset + len, apduLen - (offset + len), result.value);
    value.password = decodedValue.value;
    len += decodedValue.len;
  }
  value.len = len;
  return value;
};