From 986b04c0f12efa1c57293f147a9e734ec71f0363 Mon Sep 17 00:00:00 2001 From: Joe Tsai Date: Tue, 15 Feb 2022 16:59:59 -0800 Subject: encoding/binary: add AppendByteOrder MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit AppendByteOrder specifies new methods for LittleEndian and BigEndian for appending an unsigned integer to a byte slice. The performance of AppendXXX methods are slower than PutXXX methods since the former needs to do a few slice operations, while the latter is essentially a single integer store. In practice, existing usages of PutXXX performed slicing operations around the call such that this cost was present, regardless. name time/op PutUint16-24 0.48ns ± 2% AppendUint16-24 1.54ns ± 1% PutUint32-24 0.46ns ± 2% AppendUint32-24 0.89ns ± 1% PutUint64-24 0.46ns ± 2% AppendUint64-24 0.89ns ± 1% LittleEndianPutUint16-24 0.47ns ± 2% LittleEndianAppendUint16-24 1.54ns ± 1% LittleEndianPutUint32-24 0.45ns ± 3% LittleEndianAppendUint32-24 0.92ns ± 2% LittleEndianPutUint64-24 0.46ns ± 3% LittleEndianAppendUint64-24 0.95ns ± 4% Fixes #50601 Change-Id: I33d2bbc93a3ce01a9269feac33a2432bc1166ead Reviewed-on: https://go-review.googlesource.com/c/go/+/386017 Trust: Joseph Tsai Trust: Josh Bleecher Snyder Reviewed-by: Josh Bleecher Snyder Run-TryBot: Joseph Tsai TryBot-Result: Gopher Robot --- src/encoding/binary/binary_test.go | 114 +++++++++++++++++++++++++++++++++++-- 1 file changed, 108 insertions(+), 6 deletions(-) (limited to 'src/encoding/binary/binary_test.go') diff --git a/src/encoding/binary/binary_test.go b/src/encoding/binary/binary_test.go index 9e1b5f12db..09d08f5ee3 100644 --- a/src/encoding/binary/binary_test.go +++ b/src/encoding/binary/binary_test.go @@ -442,6 +442,65 @@ func testPutUint64SmallSliceLengthPanics() (panicked bool) { return false } +func TestByteOrder(t *testing.T) { + type byteOrder interface { + ByteOrder + AppendByteOrder + } + buf := make([]byte, 8) + for _, order := range []byteOrder{LittleEndian, BigEndian} { + const offset = 3 + for _, value := range []uint64{ + 0x0000000000000000, + 0x0123456789abcdef, + 0xfedcba9876543210, + 0xffffffffffffffff, + 0xaaaaaaaaaaaaaaaa, + math.Float64bits(math.Pi), + math.Float64bits(math.E), + } { + want16 := uint16(value) + order.PutUint16(buf[:2], want16) + if got := order.Uint16(buf[:2]); got != want16 { + t.Errorf("PutUint16: Uint16 = %v, want %v", got, want16) + } + buf = order.AppendUint16(buf[:offset], want16) + if got := order.Uint16(buf[offset:]); got != want16 { + t.Errorf("AppendUint16: Uint16 = %v, want %v", got, want16) + } + if len(buf) != offset+2 { + t.Errorf("AppendUint16: len(buf) = %d, want %d", len(buf), offset+2) + } + + want32 := uint32(value) + order.PutUint32(buf[:4], want32) + if got := order.Uint32(buf[:4]); got != want32 { + t.Errorf("PutUint32: Uint32 = %v, want %v", got, want32) + } + buf = order.AppendUint32(buf[:offset], want32) + if got := order.Uint32(buf[offset:]); got != want32 { + t.Errorf("AppendUint32: Uint32 = %v, want %v", got, want32) + } + if len(buf) != offset+4 { + t.Errorf("AppendUint32: len(buf) = %d, want %d", len(buf), offset+4) + } + + want64 := uint64(value) + order.PutUint64(buf[:8], want64) + if got := order.Uint64(buf[:8]); got != want64 { + t.Errorf("PutUint64: Uint64 = %v, want %v", got, want64) + } + buf = order.AppendUint64(buf[:offset], want64) + if got := order.Uint64(buf[offset:]); got != want64 { + t.Errorf("AppendUint64: Uint64 = %v, want %v", got, want64) + } + if len(buf) != offset+8 { + t.Errorf("AppendUint64: len(buf) = %d, want %d", len(buf), offset+8) + } + } + } +} + func TestEarlyBoundsChecks(t *testing.T) { if testUint64SmallSliceLengthPanics() != true { t.Errorf("binary.LittleEndian.Uint64 expected to panic for small slices, but didn't") @@ -596,41 +655,84 @@ func BenchmarkWriteSlice1000Int32s(b *testing.B) { func BenchmarkPutUint16(b *testing.B) { b.SetBytes(2) for i := 0; i < b.N; i++ { - BigEndian.PutUint16(putbuf[:], uint16(i)) + BigEndian.PutUint16(putbuf[:2], uint16(i)) + } +} + +func BenchmarkAppendUint16(b *testing.B) { + b.SetBytes(2) + for i := 0; i < b.N; i++ { + putbuf = BigEndian.AppendUint16(putbuf[:0], uint16(i)) } } func BenchmarkPutUint32(b *testing.B) { b.SetBytes(4) for i := 0; i < b.N; i++ { - BigEndian.PutUint32(putbuf[:], uint32(i)) + BigEndian.PutUint32(putbuf[:4], uint32(i)) + } +} + +func BenchmarkAppendUint32(b *testing.B) { + b.SetBytes(4) + for i := 0; i < b.N; i++ { + putbuf = BigEndian.AppendUint32(putbuf[:0], uint32(i)) } } func BenchmarkPutUint64(b *testing.B) { b.SetBytes(8) for i := 0; i < b.N; i++ { - BigEndian.PutUint64(putbuf[:], uint64(i)) + BigEndian.PutUint64(putbuf[:8], uint64(i)) + } +} + +func BenchmarkAppendUint64(b *testing.B) { + b.SetBytes(8) + for i := 0; i < b.N; i++ { + putbuf = BigEndian.AppendUint64(putbuf[:0], uint64(i)) } } + func BenchmarkLittleEndianPutUint16(b *testing.B) { b.SetBytes(2) for i := 0; i < b.N; i++ { - LittleEndian.PutUint16(putbuf[:], uint16(i)) + LittleEndian.PutUint16(putbuf[:2], uint16(i)) + } +} + +func BenchmarkLittleEndianAppendUint16(b *testing.B) { + b.SetBytes(2) + for i := 0; i < b.N; i++ { + putbuf = LittleEndian.AppendUint16(putbuf[:0], uint16(i)) } } func BenchmarkLittleEndianPutUint32(b *testing.B) { b.SetBytes(4) for i := 0; i < b.N; i++ { - LittleEndian.PutUint32(putbuf[:], uint32(i)) + LittleEndian.PutUint32(putbuf[:4], uint32(i)) + } +} + +func BenchmarkLittleEndianAppendUint32(b *testing.B) { + b.SetBytes(4) + for i := 0; i < b.N; i++ { + putbuf = LittleEndian.AppendUint32(putbuf[:0], uint32(i)) } } func BenchmarkLittleEndianPutUint64(b *testing.B) { b.SetBytes(8) for i := 0; i < b.N; i++ { - LittleEndian.PutUint64(putbuf[:], uint64(i)) + LittleEndian.PutUint64(putbuf[:8], uint64(i)) + } +} + +func BenchmarkLittleEndianAppendUint64(b *testing.B) { + b.SetBytes(8) + for i := 0; i < b.N; i++ { + putbuf = LittleEndian.AppendUint64(putbuf[:0], uint64(i)) } } -- cgit v1.3