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Fix decoding of signed varint32s. #134

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Merged
merged 2 commits into from
Sep 19, 2022
Merged

Fix decoding of signed varint32s. #134

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d7f3c7a
Fix decoding of signed varint32s.
varomodt Sep 9, 2022
674f9c7
Wire tests for varints
varomodt Sep 10, 2022
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10 changes: 6 additions & 4 deletions binary/decoder.js
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Original file line number Diff line number Diff line change
Expand Up @@ -481,13 +481,15 @@ jspb.BinaryDecoder.prototype.readUnsignedVarint32 = function() {


/**
* The readUnsignedVarint32 above deals with signed 32-bit varints correctly,
* so this is just an alias.
* Coerces the output of readUnsignedVarint32 to an int32.
*
* @return {number} The decoded signed 32-bit varint.
*/
jspb.BinaryDecoder.prototype.readSignedVarint32 =
jspb.BinaryDecoder.prototype.readUnsignedVarint32;
jspb.BinaryDecoder.prototype.readSignedVarint32 = function() {
// The `~` operator coerces to int32, and `~~` is the shortest expression of a cast.
// This has some edge cases (e.g. NaN becomes 0) but should be okay here.
return ~~(this.readUnsignedVarint32());
}


/**
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20 changes: 20 additions & 0 deletions binary/decoder_test.js
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Expand Up @@ -426,10 +426,20 @@ describe('binaryDecoderTest', function() {
jspb.BinaryEncoder.prototype.writeUint32,
1, 0xFFFFFFFF, Math.round);

doTestUnsignedValue(
jspb.BinaryDecoder.prototype.readUnsignedVarint32,
jspb.BinaryEncoder.prototype.writeUnsignedVarint32,
1, 0xFFFFFFFF, Math.round);

doTestUnsignedValue(
jspb.BinaryDecoder.prototype.readUint64,
jspb.BinaryEncoder.prototype.writeUint64,
1, Math.pow(2, 64) - 1025, Math.round);

doTestUnsignedValue(
jspb.BinaryDecoder.prototype.readUnsignedVarint64,
jspb.BinaryEncoder.prototype.writeUnsignedVarint64,
1, Math.pow(2, 64) - 1025, Math.round);
});


Expand All @@ -452,10 +462,20 @@ describe('binaryDecoderTest', function() {
jspb.BinaryEncoder.prototype.writeInt32,
1, -0x80000000, 0x7FFFFFFF, Math.round);

doTestSignedValue(
jspb.BinaryDecoder.prototype.readSignedVarint32,
jspb.BinaryEncoder.prototype.writeSignedVarint32,
1, -0x80000000, 0x7FFFFFFF, Math.round);

doTestSignedValue(
jspb.BinaryDecoder.prototype.readInt64,
jspb.BinaryEncoder.prototype.writeInt64,
1, -Math.pow(2, 63), Math.pow(2, 63) - 513, Math.round);

doTestSignedValue(
jspb.BinaryDecoder.prototype.readSignedVarint64,
jspb.BinaryEncoder.prototype.writeSignedVarint64,
1, -Math.pow(2, 63), Math.pow(2, 63) - 513, Math.round);
});


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