Fix 64-bit BigInt sign handling (#135)

* Fix 64-bit BigInt sign handling

* add test

* update submodule commit

Author: extremeheat

ProtoDef

@@ -1,14 +1,21 @@
 const { PartialReadError } = require('../utils')
 
-class BigIntExtended extends Array {
+class SignedBigInt extends Array {
   valueOf () { return BigInt.asIntN(64, BigInt(this[0]) << 32n) | BigInt.asUintN(32, BigInt(this[1])) }
+  toString () { return this.valueOf().toString() }
+  [Symbol.for('nodejs.util.inspect.custom')] () { return this.valueOf() }
+}
+
+class UnsignedBigInt extends Array {
+  valueOf () { return BigInt.asUintN(64, BigInt(this[0]) << 32n) | BigInt.asUintN(32, BigInt(this[1])) }
+  toString () { return this.valueOf().toString() }
   [Symbol.for('nodejs.util.inspect.custom')] () { return this.valueOf() }
 }
 
 function readI64 (buffer, offset) {
   if (offset + 8 > buffer.length) { throw new PartialReadError() }
   return {
-    value: new BigIntExtended(buffer.readInt32BE(offset), buffer.readInt32BE(offset + 4)),
+    value: new SignedBigInt(buffer.readInt32BE(offset), buffer.readInt32BE(offset + 4)),
     size: 8
   }
 }
@@ -26,7 +33,7 @@ function writeI64 (value, buffer, offset) {
 function readLI64 (buffer, offset) {
   if (offset + 8 > buffer.length) { throw new PartialReadError() }
   return {
-    value: new BigIntExtended(buffer.readInt32LE(offset + 4), buffer.readInt32LE(offset)),
+    value: new SignedBigInt(buffer.readInt32LE(offset + 4), buffer.readInt32LE(offset)),
     size: 8
   }
 }
@@ -44,7 +51,7 @@ function writeLI64 (value, buffer, offset) {
 function readU64 (buffer, offset) {
   if (offset + 8 > buffer.length) { throw new PartialReadError() }
   return {
-    value: new BigIntExtended(buffer.readUInt32BE(offset), buffer.readUInt32BE(offset + 4)),
+    value: new UnsignedBigInt(buffer.readUInt32BE(offset), buffer.readUInt32BE(offset + 4)),
     size: 8
   }
 }
@@ -62,7 +69,7 @@ function writeU64 (value, buffer, offset) {
 function readLU64 (buffer, offset) {
   if (offset + 8 > buffer.length) { throw new PartialReadError() }
   return {
-    value: new BigIntExtended(buffer.readUInt32LE(offset + 4), buffer.readUInt32LE(offset)),
+    value: new UnsignedBigInt(buffer.readUInt32LE(offset + 4), buffer.readUInt32LE(offset)),
     size: 8
   }
 }

src/datatypes/numeric.js

@@ -24,6 +24,17 @@ function testValue (type, value, buffer) {
     if (value === null) { assert.ok(actualResult.data === undefined) } else { expect(actualResult.data).to.deep.equal(value) }
     expect(actualResult.metadata.size).to.deep.equal(buffer.length)
   })
+
+  if (type === 'i64' || type === 'u64') {
+    it('reads bigint correctly ' + type, function () {
+      const [top, lower] = value.map(BigInt)
+      const joined = type === 'i64' ? BigInt.asIntN(64, (top << 32n) | lower) : BigInt.asUintN(64, (top << 32n) | lower)
+      // read
+      const actualResult = proto.parsePacketBuffer(type, buffer)
+      expect(actualResult.data.valueOf() === joined)
+      expect(actualResult.metadata.size).to.deep.equal(buffer.length)
+    })
+  }
 }
 
 function testType (type, values) {