From 819b1b45756086a1ad5c36551ce33e526c05c027 Mon Sep 17 00:00:00 2001
From: apocelipes <seve3r@outlook.com>
Date: Mon, 19 Aug 2024 20:02:37 +0000
Subject: [PATCH] time: implement the encoding.(Binary|Text)Appender for Time
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
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"Time.Marshal(Binary|Text)" could also gain some performance
improvements. Here is the benchmark highlight:
│ old │ new │
│ sec/op │ sec/op vs base │
MarshalText-8 104.00n ± 3% 67.27n ± 2% -35.32% (p=0.000 n=10)
MarshalBinary-8 31.77n ± 2% 12.13n ± 1% -61.82% (p=0.000 n=10)
geomean 57.48n 28.57n -50.30%
│ old │ new │
│ B/op │ B/op vs base │
MarshalText-8 48.00 ± 0% 0.00 ± 0% -100.00% (p=0.000 n=10)
MarshalBinary-8 16.00 ± 0% 0.00 ± 0% -100.00% (p=0.000 n=10)
│ old │ new │
│ allocs/op │ allocs/op vs base │
MarshalText-8 1.000 ± 0% 0.000 ± 0% -100.00% (p=0.000 n=10)
MarshalBinary-8 1.000 ± 0% 0.000 ± 0% -100.00% (p=0.000 n=10)
For #62384
Change-Id: I320421878a341abf8d668fd57b27292cdfa61330
GitHub-Last-Rev: e04f8df9c277481f5678208d3f1f59643bf5e429
GitHub-Pull-Request: golang/go#68942
Reviewed-on: https://go-review.googlesource.com/c/go/+/606655
Reviewed-by: Cherry Mui <cherryyz@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
---
api/next/62384.txt | 2 +
doc/next/6-stdlib/99-minor/time/62384.md | 1 +
src/time/time.go | 69 ++++++++++++++----------
src/time/time_test.go | 22 ++++++++
4 files changed, 67 insertions(+), 27 deletions(-)
create mode 100644 doc/next/6-stdlib/99-minor/time/62384.md
diff --git a/api/next/62384.txt b/api/next/62384.txt
index af7fc5363cc..0c6053d2a00 100644
--- a/api/next/62384.txt
+++ b/api/next/62384.txt
@@ -9,3 +9,5 @@ pkg math/big, method (*Float) AppendText([]uint8) ([]uint8, error) #62384
pkg math/big, method (*Int) AppendText([]uint8) ([]uint8, error) #62384
pkg math/big, method (*Rat) AppendText([]uint8) ([]uint8, error) #62384
pkg regexp, method (*Regexp) AppendText([]uint8) ([]uint8, error) #62384
+pkg time, method (Time) AppendBinary([]uint8) ([]uint8, error) #62384
+pkg time, method (Time) AppendText([]uint8) ([]uint8, error) #62384
diff --git a/doc/next/6-stdlib/99-minor/time/62384.md b/doc/next/6-stdlib/99-minor/time/62384.md
new file mode 100644
index 00000000000..99c7a39a59a
--- /dev/null
+++ b/doc/next/6-stdlib/99-minor/time/62384.md
@@ -0,0 +1 @@
+[Time] now implements the [encoding.BinaryAppender] and [encoding.TextAppender] interfaces.
diff --git a/src/time/time.go b/src/time/time.go
index 0ff7faedec3..86fedf9c141 100644
--- a/src/time/time.go
+++ b/src/time/time.go
@@ -119,9 +119,9 @@ import (
// these methods does not change the actual instant it represents, only the time
// zone in which to interpret it.
//
-// Representations of a Time value saved by the [Time.GobEncode], [Time.MarshalBinary],
-// [Time.MarshalJSON], and [Time.MarshalText] methods store the [Time.Location]'s offset, but not
-// the location name. They therefore lose information about Daylight Saving Time.
+// Representations of a Time value saved by the [Time.GobEncode], [Time.MarshalBinary], [Time.AppendBinary],
+// [Time.MarshalJSON], [Time.MarshalText] and [Time.AppendText] methods store the [Time.Location]'s offset,
+// but not the location name. They therefore lose information about Daylight Saving Time.
//
// In addition to the required “wall clock” reading, a Time may contain an optional
// reading of the current process's monotonic clock, to provide additional precision
@@ -1435,8 +1435,8 @@ const (
timeBinaryVersionV2 // For LMT only
)
-// MarshalBinary implements the encoding.BinaryMarshaler interface.
-func (t Time) MarshalBinary() ([]byte, error) {
+// AppendBinary implements the [encoding.BinaryAppender] interface.
+func (t Time) AppendBinary(b []byte) ([]byte, error) {
var offsetMin int16 // minutes east of UTC. -1 is UTC.
var offsetSec int8
version := timeBinaryVersionV1
@@ -1452,38 +1452,46 @@ func (t Time) MarshalBinary() ([]byte, error) {
offset /= 60
if offset < -32768 || offset == -1 || offset > 32767 {
- return nil, errors.New("Time.MarshalBinary: unexpected zone offset")
+ return b, errors.New("Time.MarshalBinary: unexpected zone offset")
}
offsetMin = int16(offset)
}
sec := t.sec()
nsec := t.nsec()
- enc := []byte{
- version, // byte 0 : version
- byte(sec >> 56), // bytes 1-8: seconds
- byte(sec >> 48),
- byte(sec >> 40),
- byte(sec >> 32),
- byte(sec >> 24),
- byte(sec >> 16),
- byte(sec >> 8),
+ b = append(b,
+ version, // byte 0 : version
+ byte(sec>>56), // bytes 1-8: seconds
+ byte(sec>>48),
+ byte(sec>>40),
+ byte(sec>>32),
+ byte(sec>>24),
+ byte(sec>>16),
+ byte(sec>>8),
byte(sec),
- byte(nsec >> 24), // bytes 9-12: nanoseconds
- byte(nsec >> 16),
- byte(nsec >> 8),
+ byte(nsec>>24), // bytes 9-12: nanoseconds
+ byte(nsec>>16),
+ byte(nsec>>8),
byte(nsec),
- byte(offsetMin >> 8), // bytes 13-14: zone offset in minutes
+ byte(offsetMin>>8), // bytes 13-14: zone offset in minutes
byte(offsetMin),
- }
+ )
if version == timeBinaryVersionV2 {
- enc = append(enc, byte(offsetSec))
+ b = append(b, byte(offsetSec))
}
+ return b, nil
+}
- return enc, nil
+// MarshalBinary implements the [encoding.BinaryMarshaler] interface.
+func (t Time) MarshalBinary() ([]byte, error) {
+ b, err := t.AppendBinary(make([]byte, 0, 16))
+ if err != nil {
+ return nil, err
+ }
+ return b, nil
}
-// UnmarshalBinary implements the encoding.BinaryUnmarshaler interface.
+// UnmarshalBinary implements the [encoding.BinaryUnmarshaler] interface.
func (t *Time) UnmarshalBinary(data []byte) error {
buf := data
if len(buf) == 0 {
@@ -1576,12 +1584,11 @@ func (t *Time) UnmarshalJSON(data []byte) error {
return err
}
-// MarshalText implements the [encoding.TextMarshaler] interface.
+// AppendText implements the [encoding.TextAppender] interface.
// The time is formatted in RFC 3339 format with sub-second precision.
// If the timestamp cannot be represented as valid RFC 3339
-// (e.g., the year is out of range), then an error is reported.
-func (t Time) MarshalText() ([]byte, error) {
- b := make([]byte, 0, len(RFC3339Nano))
+// (e.g., the year is out of range), then an error is returned.
+func (t Time) AppendText(b []byte) ([]byte, error) {
b, err := t.appendStrictRFC3339(b)
if err != nil {
return nil, errors.New("Time.MarshalText: " + err.Error())
@@ -1589,6 +1596,14 @@ func (t Time) MarshalText() ([]byte, error) {
return b, nil
}
+// MarshalText implements the [encoding.TextMarshaler] interface. The output
+// matches that of calling the [Time.AppendText] method.
+//
+// See [Time.AppendText] for more information.
+func (t Time) MarshalText() ([]byte, error) {
+ return t.AppendText(make([]byte, 0, len(RFC3339Nano)))
+}
+
// UnmarshalText implements the [encoding.TextUnmarshaler] interface.
// The time must be in the RFC 3339 format.
func (t *Time) UnmarshalText(data []byte) error {
diff --git a/src/time/time_test.go b/src/time/time_test.go
index e375d3f9734..18fd21c27c1 100644
--- a/src/time/time_test.go
+++ b/src/time/time_test.go
@@ -1403,6 +1403,13 @@ var defaultLocTests = []struct {
{"UnixMilli", func(t1, t2 Time) bool { return t1.UnixMilli() == t2.UnixMilli() }},
{"UnixMicro", func(t1, t2 Time) bool { return t1.UnixMicro() == t2.UnixMicro() }},
+ {"AppendBinary", func(t1, t2 Time) bool {
+ buf1 := make([]byte, 4, 32)
+ buf2 := make([]byte, 4, 32)
+ a1, b1 := t1.AppendBinary(buf1)
+ a2, b2 := t2.AppendBinary(buf2)
+ return bytes.Equal(a1[4:], a2[4:]) && b1 == b2
+ }},
{"MarshalBinary", func(t1, t2 Time) bool {
a1, b1 := t1.MarshalBinary()
a2, b2 := t2.MarshalBinary()
@@ -1418,6 +1425,14 @@ var defaultLocTests = []struct {
a2, b2 := t2.MarshalJSON()
return bytes.Equal(a1, a2) && b1 == b2
}},
+ {"AppendText", func(t1, t2 Time) bool {
+ maxCap := len(RFC3339Nano) + 4
+ buf1 := make([]byte, 4, maxCap)
+ buf2 := make([]byte, 4, maxCap)
+ a1, b1 := t1.AppendText(buf1)
+ a2, b2 := t2.AppendText(buf2)
+ return bytes.Equal(a1[4:], a2[4:]) && b1 == b2
+ }},
{"MarshalText", func(t1, t2 Time) bool {
a1, b1 := t1.MarshalText()
a2, b2 := t2.MarshalText()
@@ -1510,6 +1525,13 @@ func BenchmarkMarshalText(b *testing.B) {
}
}
+func BenchmarkMarshalBinary(b *testing.B) {
+ t := Now()
+ for i := 0; i < b.N; i++ {
+ t.MarshalBinary()
+ }
+}
+
func BenchmarkParse(b *testing.B) {
for i := 0; i < b.N; i++ {
Parse(ANSIC, "Mon Jan 2 15:04:05 2006")
--
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