Types greater than 512 fail. Falls short of ASN1_MAX_OBJECT

[NateZimmer]

Node Version: 9.1

Node BACstack Version: 0.0.1-beta.10 (though I believe this to be in the present as well)

• Bug Report

Current Behavior (Bug Report)

Bacnet types that are greater than 512 cause an exception. ASN1_MAX_OBJECT is defined as 0x3FF / 1023.
baAsn1.encodeContextObjectId(buffer, 0, objectType, objectInstance); returns an exception for these values when it shouldn't be since they are less than 0x3FF.

The issue is the following lines of code:
asn1.js

const encodeBacnetObjectId = module.exports.encodeBacnetObjectId = (buffer, objectType, instance) => {
  const value = ((objectType & baEnum.ASN1_MAX_OBJECT) << baEnum.ASN1_INSTANCE_BITS) | (instance & baEnum.ASN1_MAX_INSTANCE);
  encodeUnsigned(buffer, value, 4);
};

value isn't intrinsically an unsigned int. It is an int. Hence it propagates a negative value which eventually throws an error when put into an unsigned buffer. A solution is as follows:

const encodeBacnetObjectId = module.exports.encodeBacnetObjectId = (buffer, objectType, instance) => {
  const value = (((objectType & baEnum.ASN1_MAX_OBJECT) << baEnum.ASN1_INSTANCE_BITS) | (instance & baEnum.ASN1_MAX_INSTANCE))>>>0;
  encodeUnsigned(buffer, value, 4);
};

Another example:
(512 & 0x3FF) << 22 | (1 & 0x3FFFFF ) = -2147483647
((512 & 0x3FF) << 22 | (1 & 0x3FFFFF )) >>> 0 = 2147483649

[fh1ch]

@NateZimmer sorry for the delay on this one. The whole project was more or less on ice for a while, since I was busy with other stuff...

However, a bight thanks for reporting this issue and already providing a solution 🎉 I've added it in #133 and covered it with some tests. It should be available with the next release.