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time: parse and format fractional seconds

Browse Source 
R=golang-dev, rogpeppe, r, dsymonds, bradfitz, fvbommel
CC=golang-dev
https://golang.org/cl/4830065
This commit is contained in:
Rob Pike 2011-08-08 07:50:17 +10:00
parent 4c268b335f
commit 3c10403784
2 changed files with 113 additions and 24 deletions
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66
src/pkg/time/format.go
View File

@ -26,6 +26,9 @@ const (
// replaced by a digit if the following number (a day) has two digits; for
// compatibility with fixed-width Unix time formats.
//
// A decimal point followed by one or more zeros represents a
// fractional second.
//
// Numeric time zone offsets format as follows:
// -0700 ±hhmm
// -07:00 ±hh:mm
@ -45,6 +48,11 @@ const (
RFC1123 = "Mon, 02 Jan 2006 15:04:05 MST"
RFC3339 = "2006-01-02T15:04:05Z07:00"
Kitchen = "3:04PM"
// Handy time stamps.
Stamp = "Jan _2 15:04:05"
StampMilli = "Jan _2 15:04:05.000"
StampMicro = "Jan _2 15:04:05.000000"
StampNano = "Jan _2 15:04:05.000000000"
)
const (
@ -154,6 +162,16 @@ func nextStdChunk(layout string) (prefix, std, suffix string) {
if len(layout) >= i+6 && layout[i:i+6] == stdISO8601ColonTZ {
return layout[0:i], layout[i : i+6], layout[i+6:]
}
case '.': // .000 - multiple digits of zeros (only) for fractional seconds.
numZeros := 0
var j int
for j = i + 1; j < len(layout) && layout[j] == '0'; j++ {
numZeros++
}
// String of digits must end here - only fractional second is all zeros.
if numZeros > 0 && (j >= len(layout) || layout[j] < '0' || '9' < layout[j]) {
return layout[0:i], layout[i : i+1+numZeros], layout[i+1+numZeros:]
}
}
}
return layout, "", ""
@ -230,6 +248,21 @@ func pad(i int, padding string) string {
func zeroPad(i int) string { return pad(i, "0") }
// formatNano formats a fractional second, as nanoseconds.
func formatNano(nanosec, n int) string {
// User might give us bad data. Make sure it's positive and in range.
// They'll get nonsense output but it will have the right format.
s := strconv.Uitoa(uint(nanosec) % 1e9)
// Zero pad left without fmt.
if len(s) < 9 {
s = "000000000"[:9-len(s)] + s
}
if n > 9 {
n = 9
}
return "." + s[:n]
}
// Format returns a textual representation of the time value formatted
// according to layout. The layout defines the format by showing the
// representation of a standard time, which is then used to describe
@ -340,6 +373,10 @@ func (t *Time) Format(layout string) string {
p += zeroPad(zone / 60)
p += zeroPad(zone % 60)
}
default:
if len(std) >= 2 && std[0:2] == ".0" {
p = formatNano(t.Nanosecond, len(std)-1)
}
}
b.WriteString(p)
layout = suffix
@ -355,7 +392,7 @@ func (t *Time) String() string {
return t.Format(UnixDate)
}
var errBad = os.NewError("bad") // just a marker; not returned to user
var errBad = os.NewError("bad value for field") // placeholder not passed to user
// ParseError describes a problem parsing a time string.
type ParseError struct {
@ -620,6 +657,33 @@ func Parse(alayout, avalue string) (*Time, os.Error) {
if offset, found := lookupByName(p); found {
t.ZoneOffset = offset
}
default:
if len(value) < len(std) {
err = errBad
break
}
if len(std) >= 2 && std[0:2] == ".0" {
if value[0] != '.' {
err = errBad
break
}
t.Nanosecond, err = strconv.Atoi(value[1:len(std)])
if err != nil {
break
}
if t.Nanosecond < 0 || t.Nanosecond >= 1e9 {
rangeErrString = "fractional second"
break
}
value = value[len(std):]
// We need nanoseconds, which means scaling by the number
// of missing digits in the format, maximum length 10. If it's
// longer than 10, we won't scale.
scaleDigits := 10 - len(std)
for i := 0; i < scaleDigits; i++ {
t.Nanosecond *= 10
}
}
}
if rangeErrString != "" {
return nil, &ParseError{alayout, avalue, std, value, ": " + rangeErrString + " out of range"}

71
src/pkg/time/time_test.go
View File

@ -6,6 +6,7 @@ package time_test
import (
"os"
"strconv"
"strings"
"testing"
"testing/quick"
@ -213,11 +214,16 @@ var formatTests = []FormatTest{
{"am/pm", "3pm", "9pm"},
{"AM/PM", "3PM", "9PM"},
{"two-digit year", "06 01 02", "09 02 04"},
// Time stamps, Fractional seconds.
{"Stamp", Stamp, "Feb 4 21:00:57"},
{"StampMilli", StampMilli, "Feb 4 21:00:57.012"},
{"StampMicro", StampMicro, "Feb 4 21:00:57.012345"},
{"StampNano", StampNano, "Feb 4 21:00:57.012345678"},
}
func TestFormat(t *testing.T) {
// The numeric time represents Thu Feb 4 21:00:57 PST 2010
time := SecondsToLocalTime(1233810057)
// The numeric time represents Thu Feb 4 21:00:57.012345678 PST 2010
time := NanosecondsToLocalTime(1233810057012345678)
for _, test := range formatTests {
result := time.Format(test.format)
if result != test.result {
@ -227,25 +233,33 @@ func TestFormat(t *testing.T) {
}
type ParseTest struct {
name string
format string
value string
hasTZ bool // contains a time zone
hasWD bool // contains a weekday
yearSign int64 // sign of year
name string
format string
value string
hasTZ bool // contains a time zone
hasWD bool // contains a weekday
yearSign int64 // sign of year
fracDigits int // number of digits of fractional second
}
var parseTests = []ParseTest{
{"ANSIC", ANSIC, "Thu Feb 4 21:00:57 2010", false, true, 1},
{"UnixDate", UnixDate, "Thu Feb 4 21:00:57 PST 2010", true, true, 1},
{"RubyDate", RubyDate, "Thu Feb 04 21:00:57 -0800 2010", true, true, 1},
{"RFC850", RFC850, "Thursday, 04-Feb-10 21:00:57 PST", true, true, 1},
{"RFC1123", RFC1123, "Thu, 04 Feb 2010 21:00:57 PST", true, true, 1},
{"RFC3339", RFC3339, "2010-02-04T21:00:57-08:00", true, false, 1},
{"custom: \"2006-01-02 15:04:05-07\"", "2006-01-02 15:04:05-07", "2010-02-04 21:00:57-08", true, false, 1},
{"ANSIC", ANSIC, "Thu Feb 4 21:00:57 2010", false, true, 1, 0},
{"UnixDate", UnixDate, "Thu Feb 4 21:00:57 PST 2010", true, true, 1, 0},
{"RubyDate", RubyDate, "Thu Feb 04 21:00:57 -0800 2010", true, true, 1, 0},
{"RFC850", RFC850, "Thursday, 04-Feb-10 21:00:57 PST", true, true, 1, 0},
{"RFC1123", RFC1123, "Thu, 04 Feb 2010 21:00:57 PST", true, true, 1, 0},
{"RFC3339", RFC3339, "2010-02-04T21:00:57-08:00", true, false, 1, 0},
{"custom: \"2006-01-02 15:04:05-07\"", "2006-01-02 15:04:05-07", "2010-02-04 21:00:57-08", true, false, 1, 0},
// Amount of white space should not matter.
{"ANSIC", ANSIC, "Thu Feb 4 21:00:57 2010", false, true, 1},
{"ANSIC", ANSIC, "Thu Feb 4 21:00:57 2010", false, true, 1},
{"ANSIC", ANSIC, "Thu Feb 4 21:00:57 2010", false, true, 1, 0},
{"ANSIC", ANSIC, "Thu Feb 4 21:00:57 2010", false, true, 1, 0},
// Fractional seconds.
{"millisecond", "Mon Jan _2 15:04:05.000 2006", "Thu Feb 4 21:00:57.012 2010", false, true, 1, 3},
{"microsecond", "Mon Jan _2 15:04:05.000000 2006", "Thu Feb 4 21:00:57.012345 2010", false, true, 1, 6},
{"nanosecond", "Mon Jan _2 15:04:05.000000000 2006", "Thu Feb 4 21:00:57.012345678 2010", false, true, 1, 9},
// Leading zeros in other places should not be taken as fractional seconds.
{"zero1", "2006.01.02.15.04.05.0", "2010.02.04.21.00.57.0", false, false, 1, 1},
{"zero2", "2006.01.02.15.04.05.00", "2010.02.04.21.00.57.01", false, false, 1, 2},
}
func TestParse(t *testing.T) {
@ -260,11 +274,11 @@ func TestParse(t *testing.T) {
}
var rubyTests = []ParseTest{
{"RubyDate", RubyDate, "Thu Feb 04 21:00:57 -0800 2010", true, true, 1},
{"RubyDate", RubyDate, "Thu Feb 04 21:00:57 -0800 2010", true, true, 1, 0},
// Ignore the time zone in the test. If it parses, it'll be OK.
{"RubyDate", RubyDate, "Thu Feb 04 21:00:57 -0000 2010", false, true, 1},
{"RubyDate", RubyDate, "Thu Feb 04 21:00:57 +0000 2010", false, true, 1},
{"RubyDate", RubyDate, "Thu Feb 04 21:00:57 +1130 2010", false, true, 1},
{"RubyDate", RubyDate, "Thu Feb 04 21:00:57 -0000 2010", false, true, 1, 0},
{"RubyDate", RubyDate, "Thu Feb 04 21:00:57 +0000 2010", false, true, 1, 0},
{"RubyDate", RubyDate, "Thu Feb 04 21:00:57 +1130 2010", false, true, 1, 0},
}
// Problematic time zone format needs special tests.
@ -299,6 +313,14 @@ func checkTime(time *Time, test *ParseTest, t *testing.T) {
if time.Second != 57 {
t.Errorf("%s: bad second: %d not %d", test.name, time.Second, 57)
}
// Nanoseconds must be checked against the precision of the input.
nanosec, err := strconv.Atoui("012345678"[:test.fracDigits] + "000000000"[:9-test.fracDigits])
if err != nil {
panic(err)
}
if time.Nanosecond != int(nanosec) {
t.Errorf("%s: bad nanosecond: %d not %d", test.name, time.Nanosecond, nanosec)
}
if test.hasTZ && time.ZoneOffset != -28800 {
t.Errorf("%s: bad tz offset: %d not %d", test.name, time.ZoneOffset, -28800)
}
@ -345,11 +367,14 @@ type ParseErrorTest struct {
}
var parseErrorTests = []ParseErrorTest{
{ANSIC, "Feb 4 21:00:60 2010", "parse"}, // cannot parse Feb as Mon
{ANSIC, "Thu Feb 4 21:00:57 @2010", "parse"},
{ANSIC, "Feb 4 21:00:60 2010", "cannot parse"}, // cannot parse Feb as Mon
{ANSIC, "Thu Feb 4 21:00:57 @2010", "cannot parse"},
{ANSIC, "Thu Feb 4 21:00:60 2010", "second out of range"},
{ANSIC, "Thu Feb 4 21:61:57 2010", "minute out of range"},
{ANSIC, "Thu Feb 4 24:00:60 2010", "hour out of range"},
{"Mon Jan _2 15:04:05.000 2006", "Thu Feb 4 23:00:59x01 2010", "cannot parse"},
{"Mon Jan _2 15:04:05.000 2006", "Thu Feb 4 23:00:59.xxx 2010", "cannot parse"},
{"Mon Jan _2 15:04:05.000 2006", "Thu Feb 4 23:00:59.-123 2010", "fractional second out of range"},
}
func TestParseErrors(t *testing.T) {