v1.6.0

This was a performance focused update with some minor corrections, and significant
reduction in generated code verbosity. Benchmarks were introduced and executed before
and after the changes. Serialization and deserialization both had gains, but serialization
by far had the biggest improvements. See the results below.

Environment

AMD Ryzen 5 3600X 4.41GHz, 1 CPU, 12 logical / 6 physical cores, Ubuntu 26.04.1 LTS.
.NET 10.0.12 (X64 RyuJIT AVX2), SDK 10.0.112, BenchmarkDotNet 0.15.2, DefaultJob.

• Exhaustive benchmarks refer to an nsd message containing all supported types and fields.
  • See: Needlefish.Benchmarks/Models/Exhaustive.nsd
• Nested benchmarks refer to an nsd message containing 3 layers of nested nsd submessages.
  • See: Needlefish.Benchmarks/Models/Nested.nsd
• Primitive benchmarks refer to an nsd message containing all supported primitive types.
  • See: Needlefish.Benchmarks/Models/Primitives.nsd

Before - Needlefish v3.3.0 / nsdc v1.5.0 / Generators v1.2.0

Type	Method	People	StringLength	Mean	Allocated
DeserializePrimitivesBenchmarks	Unpack	-	-	28.33 ns	-
DeserializePrimitivesBenchmarks	Deserialize	-	-	30.89 ns	-
SerializeNestedBenchmarks	GetSize	16	-	111.83 ns	-
SerializeNestedBenchmarks	SerializeInto	16	-	951.35 ns	-
SerializeNestedBenchmarks	Serialize	16	-	1,262.31 ns	3448 B
SerializeNestedBenchmarks	GetSize	128	-	935.66 ns	-
SerializeNestedBenchmarks	SerializeInto	128	-	7,441.16 ns	-
SerializeNestedBenchmarks	Serialize	128	-	10,286.51 ns	27752 B
SerializeExhaustiveBenchmarks	GetSize	-	16	13.76 ns	-
SerializeExhaustiveBenchmarks	SerializeInto	-	16	72.57 ns	-
SerializeExhaustiveBenchmarks	Serialize	-	16	146.25 ns	416 B
SerializeExhaustiveBenchmarks	GetSize	-	1024	13.50 ns	-
SerializeExhaustiveBenchmarks	SerializeInto	-	1024	1,480.25 ns	-
SerializeExhaustiveBenchmarks	Serialize	-	1024	1,829.47 ns	4448 B
DeserializeExhaustiveBenchmarks	Unpack_Fresh	-	16	300.15 ns	640 B
DeserializeExhaustiveBenchmarks	Unpack_Reused	-	16	310.43 ns	640 B
DeserializeExhaustiveBenchmarks	Deserialize	-	16	324.69 ns	640 B
DeserializeExhaustiveBenchmarks	Unpack_Fresh	-	1024	545.12 ns	4672 B
DeserializeExhaustiveBenchmarks	Unpack_Reused	-	1024	636.42 ns	4672 B
DeserializeExhaustiveBenchmarks	Deserialize	-	1024	594.05 ns	4672 B

After - Needlefish v3.4.0 / nsdc v1.6.0 / Generators v1.3.0

Type	Method	People	StringLength	Mean	Allocated
DeserializePrimitivesBenchmarks	Unpack	-	-	22.17 ns	-
DeserializePrimitivesBenchmarks	Deserialize	-	-	22.72 ns	-
SerializeNestedBenchmarks	GetSize	16	-	103.78 ns	-
SerializeNestedBenchmarks	SerializeInto	16	-	717.19 ns	-
SerializeNestedBenchmarks	Serialize	16	-	1,058.82 ns	3448 B
SerializeNestedBenchmarks	GetSize	128	-	945.08 ns	-
SerializeNestedBenchmarks	SerializeInto	128	-	5,956.72 ns	-
SerializeNestedBenchmarks	Serialize	128	-	7,936.31 ns	27752 B
SerializeExhaustiveBenchmarks	GetSize	-	16	12.57 ns	-
SerializeExhaustiveBenchmarks	SerializeInto	-	16	62.97 ns	-
SerializeExhaustiveBenchmarks	Serialize	-	16	97.15 ns	416 B
SerializeExhaustiveBenchmarks	GetSize	-	1024	12.54 ns	-
SerializeExhaustiveBenchmarks	SerializeInto	-	1024	89.58 ns	-
SerializeExhaustiveBenchmarks	Serialize	-	1024	291.56 ns	4448 B
DeserializeExhaustiveBenchmarks	Unpack_Fresh	-	16	260.72 ns	640 B
DeserializeExhaustiveBenchmarks	Unpack_Reused	-	16	296.47 ns	640 B
DeserializeExhaustiveBenchmarks	Deserialize	-	16	274.07 ns	640 B
DeserializeExhaustiveBenchmarks	Unpack_Fresh	-	1024	473.87 ns	4672 B
DeserializeExhaustiveBenchmarks	Unpack_Reused	-	1024	468.97 ns	4672 B
DeserializeExhaustiveBenchmarks	Deserialize	-	1024	529.37 ns	4672 B

Comparison

Benchmark	Before	After	Change
Exhaustive SerializeInto, 1024 char	1,480.25 ns	89.58 ns	-94%
Exhaustive Serialize, 1024 char	1,829.47 ns	291.56 ns	-84%
Exhaustive Serialize, 16 char	146.25 ns	97.15 ns	-34%
Nested SerializeInto, 128 people	7,441.16 ns	5,956.72 ns	-20%
Nested Serialize, 128 people	10,286.51 ns	7,936.31 ns	-23%
Nested SerializeInto, 16 people	951.35 ns	717.19 ns	-25%
Nested Serialize, 16 people	1,262.31 ns	1,058.82 ns	-16%
Exhaustive SerializeInto, 16 char	72.57 ns	62.97 ns	-13%
Exhaustive GetSize	~13.6 ns	~12.6 ns	-8%
Nested GetSize	~1,045 ns	~1,024 ns	~2%
Exhaustive Unpack_Fresh	300.15 / 545.12 ns	260.72 / 473.87 ns	-13%
Exhaustive Unpack_Reused	310.43 / 636.42 ns	296.47 / 468.97 ns	-5% / -26%
Exhaustive Deserialize	324.69 / 594.05 ns	274.07 / 529.37 ns	-16% / -11%
Primitives Unpack / Deserialize	28.33 / 30.89 ns	22.17 / 22.72 ns	-22% / -26%

What changed

• The serializer writes nested object lengths by patching the length prefix after writing the
  child (SerializeCore), so GetSize is never called from the serialization path and each
  node is visited once.
• String and primitive-array copies use Buffer.MemoryCopy above a 64-byte threshold and an
  inline loop below it (memcpy call overhead dominates tiny copies).
• The deserializer collapsed its three duplicated Unpack bodies into one
  UnpackCore(byte*, byte*) reached through a ReadOnlySpan<byte> UnpackSpan. Generated
  output is roughly half the size (SampleNsd.cs 5,074 to 2,587 lines, AddressBook.cs 2,046 to 1,263 lines)
  and JIT time drops with it.
• Fixed:
  • GetSize threw NullReferenceException when a string[] contained a null element.
  • Big-endian deserialization mutated the caller's input buffer (including ReadOnlySpan).
    string.Create is now used for the swap path.
  • Big-endian float/double serialization converted the byte-swapped bits numerically instead
    of reinterpreting them.
  • Optional objects deserialized via OptionalSubmessage.Value.Unpack(...), which mutated a
    temporary value. They now unpack into a local value and assign back.
  • Values above 65,535 bytes (strings, arrays, nested objects) now throw
    InvalidOperationException instead of silently truncating the length prefix.
  • The README incorrectly stated enum values were 16-bit signed integers on the wire.
    Now it correctly states they are 32-bit.

Full Changelog: v1.5.0...v1.6.0

v1.5.0

Full Changelog: v1.4.0...v1.5.0

v1.4.0

Full Changelog: v1.3.4...v1.4.0

v1.3.4

Full Changelog: v1.3.3...v1.3.4

v1.3.3

Full Changelog: v1.3.2...v1.3.3

Fixed:

• Malformed data can be read out of bounds #4
• Generated Serialize methods are incurring copies #3

v1.3.2

Full Changelog: v1.3.1...v1.3.2

• Fixed missing overload for ReadOnlySpan deserialization.

v1.3.1

• Fixed submessage deserialization missing a Span overload.

Full Changelog: v1.3.0...v1.3.1

v1.3.0

• Changed version field to a string
• Added --partial and -p args to nsdc to generate C# types with the partial keyword

Full Changelog: v1.2.1...v1.3.0

v1.2.1

Full Changelog: v1.2.0...v1.2.1

Fix deeply nested messages getting corrupted.

v1.2.0

Full Changelog: v1.1.4...v1.2.0

Added ReadOnlySpan deserialization support.