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.go | 73 +++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 70 insertions(+), 3 deletions(-) (limited to 'src/encoding/binary/binary.go') diff --git a/src/encoding/binary/binary.go b/src/encoding/binary/binary.go index ee933461ee..0681511fbb 100644 --- a/src/encoding/binary/binary.go +++ b/src/encoding/binary/binary.go @@ -29,7 +29,7 @@ import ( "sync" ) -// A ByteOrder specifies how to convert byte sequences into +// A ByteOrder specifies how to convert byte slices into // 16-, 32-, or 64-bit unsigned integers. type ByteOrder interface { Uint16([]byte) uint16 @@ -41,10 +41,19 @@ type ByteOrder interface { String() string } -// LittleEndian is the little-endian implementation of ByteOrder. +// AppendByteOrder specifies how to append 16-, 32-, or 64-bit unsigned integers +// into a byte slice. +type AppendByteOrder interface { + AppendUint16([]byte, uint16) []byte + AppendUint32([]byte, uint32) []byte + AppendUint64([]byte, uint64) []byte + String() string +} + +// LittleEndian is the little-endian implementation of ByteOrder and AppendByteOrder. var LittleEndian littleEndian -// BigEndian is the big-endian implementation of ByteOrder. +// BigEndian is the big-endian implementation of ByteOrder and AppendByteOrder. var BigEndian bigEndian type littleEndian struct{} @@ -60,6 +69,13 @@ func (littleEndian) PutUint16(b []byte, v uint16) { b[1] = byte(v >> 8) } +func (littleEndian) AppendUint16(b []byte, v uint16) []byte { + return append(b, + byte(v), + byte(v>>8), + ) +} + func (littleEndian) Uint32(b []byte) uint32 { _ = b[3] // bounds check hint to compiler; see golang.org/issue/14808 return uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24 @@ -73,6 +89,15 @@ func (littleEndian) PutUint32(b []byte, v uint32) { b[3] = byte(v >> 24) } +func (littleEndian) AppendUint32(b []byte, v uint32) []byte { + return append(b, + byte(v), + byte(v>>8), + byte(v>>16), + byte(v>>24), + ) +} + func (littleEndian) Uint64(b []byte) uint64 { _ = b[7] // bounds check hint to compiler; see golang.org/issue/14808 return uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 | @@ -91,6 +116,19 @@ func (littleEndian) PutUint64(b []byte, v uint64) { b[7] = byte(v >> 56) } +func (littleEndian) AppendUint64(b []byte, v uint64) []byte { + return append(b, + byte(v), + byte(v>>8), + byte(v>>16), + byte(v>>24), + byte(v>>32), + byte(v>>40), + byte(v>>48), + byte(v>>56), + ) +} + func (littleEndian) String() string { return "LittleEndian" } func (littleEndian) GoString() string { return "binary.LittleEndian" } @@ -108,6 +146,13 @@ func (bigEndian) PutUint16(b []byte, v uint16) { b[1] = byte(v) } +func (bigEndian) AppendUint16(b []byte, v uint16) []byte { + return append(b, + byte(v>>8), + byte(v), + ) +} + func (bigEndian) Uint32(b []byte) uint32 { _ = b[3] // bounds check hint to compiler; see golang.org/issue/14808 return uint32(b[3]) | uint32(b[2])<<8 | uint32(b[1])<<16 | uint32(b[0])<<24 @@ -121,6 +166,15 @@ func (bigEndian) PutUint32(b []byte, v uint32) { b[3] = byte(v) } +func (bigEndian) AppendUint32(b []byte, v uint32) []byte { + return append(b, + byte(v>>24), + byte(v>>16), + byte(v>>8), + byte(v), + ) +} + func (bigEndian) Uint64(b []byte) uint64 { _ = b[7] // bounds check hint to compiler; see golang.org/issue/14808 return uint64(b[7]) | uint64(b[6])<<8 | uint64(b[5])<<16 | uint64(b[4])<<24 | @@ -139,6 +193,19 @@ func (bigEndian) PutUint64(b []byte, v uint64) { b[7] = byte(v) } +func (bigEndian) AppendUint64(b []byte, v uint64) []byte { + return append(b, + byte(v>>56), + byte(v>>48), + byte(v>>40), + byte(v>>32), + byte(v>>24), + byte(v>>16), + byte(v>>8), + byte(v), + ) +} + func (bigEndian) String() string { return "BigEndian" } func (bigEndian) GoString() string { return "binary.BigEndian" } -- cgit v1.3