Merge pull request #133 from fh1ch/fix/object-type-larger-512

fix(asn1): correct encoding of object-types > 512

Author: fh1ch

lib/asn1.js

@@ -86,7 +86,7 @@ const decodeEnumerated = module.exports.decodeEnumerated = (buffer, offset, lenV
 };
 
 const encodeBacnetObjectId = module.exports.encodeBacnetObjectId = (buffer, objectType, instance) => {
-  const value = ((objectType & baEnum.ASN1_MAX_OBJECT) << baEnum.ASN1_INSTANCE_BITS) | (instance & baEnum.ASN1_MAX_INSTANCE);
+  const value = (((objectType & baEnum.ASN1_MAX_OBJECT) << baEnum.ASN1_INSTANCE_BITS) | (instance & baEnum.ASN1_MAX_INSTANCE)) >>> 0;
   encodeUnsigned(buffer, value, 4);
 };
 

test/unit/asn1.spec.js

@@ -31,4 +31,12 @@ describe('bacstack - ASN1 layer', () => {
       expect(result).to.deep.equal({len: 4, value: 4294967295});
     });
   });
+
+  describe('encodeBacnetObjectId', () => {
+    it('should successfully encode with object-type > 512', () => {
+      const buffer = {buffer: Buffer.alloc(4), offset: 0};
+      baAsn1.encodeBacnetObjectId(buffer, 600, 600);
+      expect(buffer).to.deep.equal({buffer: Buffer.from([150, 0, 2, 88]), offset: 4});
+    });
+  });
 });

test/unit/service-read-property.spec.js

@@ -17,6 +17,17 @@ describe('bacstack - Services layer ReadProperty unit', () => {
     });
   });
 
+  it('should successfully encode and decode with object-tye > 512', () => {
+    const buffer = utils.getBuffer();
+    baServices.readProperty.encode(buffer, 630, 5, 12, 0xFFFFFFFF);
+    const result = baServices.readProperty.decode(buffer.buffer, 0, buffer.offset);
+    delete result.len;
+    expect(result).to.deep.equal({
+      objectId: {type: 630, instance: 5},
+      property: {id: 12, index: 0xFFFFFFFF}
+    });
+  });
+
   it('should successfully encode and decode with array index', () => {
     const buffer = utils.getBuffer();
     baServices.readProperty.encode(buffer, 4, 630, 85, 2);