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// Copyright 2010 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package time
import "errors"
// These are predefined layouts for use in Time.Format and time.Parse.
// The reference time used in these layouts is the specific time stamp:
//
// 01/02 03:04:05PM '06 -0700
//
// (January 2, 15:04:05, 2006, in time zone seven hours west of GMT).
// That value is recorded as the constant named Layout, listed below. As a Unix
// time, this is 1136239445. Since MST is GMT-0700, the reference would be
// printed by the Unix date command as:
//
// Mon Jan 2 15:04:05 MST 2006
//
// It is a regrettable historic error that the date uses the American convention
// of putting the numerical month before the day.
//
// The example for Time.Format demonstrates the working of the layout string
// in detail and is a good reference.
//
// Note that the RFC822, RFC850, and RFC1123 formats should be applied
// only to local times. Applying them to UTC times will use "UTC" as the
// time zone abbreviation, while strictly speaking those RFCs require the
// use of "GMT" in that case.
// In general RFC1123Z should be used instead of RFC1123 for servers
// that insist on that format, and RFC3339 should be preferred for new protocols.
// RFC3339, RFC822, RFC822Z, RFC1123, and RFC1123Z are useful for formatting;
// when used with time.Parse they do not accept all the time formats
// permitted by the RFCs and they do accept time formats not formally defined.
// The RFC3339Nano format removes trailing zeros from the seconds field
// and thus may not sort correctly once formatted.
//
// Most programs can use one of the defined constants as the layout passed to
// Format or Parse. The rest of this comment can be ignored unless you are
// creating a custom layout string.
//
// To define your own format, write down what the reference time would look like
// formatted your way; see the values of constants like ANSIC, StampMicro or
// Kitchen for examples. The model is to demonstrate what the reference time
// looks like so that the Format and Parse methods can apply the same
// transformation to a general time value.
//
// Here is a summary of the components of a layout string. Each element shows by
// example the formatting of an element of the reference time. Only these values
// are recognized. Text in the layout string that is not recognized as part of
// the reference time is echoed verbatim during Format and expected to appear
// verbatim in the input to Parse.
//
// Year: "2006" "06"
// Month: "Jan" "January"
// Textual day of the week: "Mon" "Monday"
// Numeric day of the month: "2" "_2" "02"
// Numeric day of the year: "__2" "002"
// Hour: "15" "3" "03" (PM or AM)
// Minute: "4" "04"
// Second: "5" "05"
// AM/PM mark: "PM"
//
// Numeric time zone offsets format as follows:
//
// "-0700" ±hhmm
// "-07:00" ±hh:mm
// "-07" ±hh
//
// Replacing the sign in the format with a Z triggers
// the ISO 8601 behavior of printing Z instead of an
// offset for the UTC zone. Thus:
//
// "Z0700" Z or ±hhmm
// "Z07:00" Z or ±hh:mm
// "Z07" Z or ±hh
//
// Within the format string, the underscores in "_2" and "__2" represent spaces
// that may be replaced by digits if the following number has multiple digits,
// for compatibility with fixed-width Unix time formats. A leading zero represents
// a zero-padded value.
//
// The formats __2 and 002 are space-padded and zero-padded
// three-character day of year; there is no unpadded day of year format.
//
// A comma or decimal point followed by one or more zeros represents
// a fractional second, printed to the given number of decimal places.
// A comma or decimal point followed by one or more nines represents
// a fractional second, printed to the given number of decimal places, with
// trailing zeros removed.
// For example "15:04:05,000" or "15:04:05.000" formats or parses with
// millisecond precision.
//
// Some valid layouts are invalid time values for time.Parse, due to formats
// such as _ for space padding and Z for zone information.
const (
Layout = "01/02 03:04:05PM '06 -0700" // The reference time, in numerical order.
ANSIC = "Mon Jan _2 15:04:05 2006"
UnixDate = "Mon Jan _2 15:04:05 MST 2006"
RubyDate = "Mon Jan 02 15:04:05 -0700 2006"
RFC822 = "02 Jan 06 15:04 MST"
RFC822Z = "02 Jan 06 15:04 -0700" // RFC822 with numeric zone
RFC850 = "Monday, 02-Jan-06 15:04:05 MST"
RFC1123 = "Mon, 02 Jan 2006 15:04:05 MST"
RFC1123Z = "Mon, 02 Jan 2006 15:04:05 -0700" // RFC1123 with numeric zone
RFC3339 = "2006-01-02T15:04:05Z07:00"
RFC3339Nano = "2006-01-02T15:04:05.999999999Z07:00"
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 (
_ = iota
stdLongMonth = iota + stdNeedDate // "January"
stdMonth // "Jan"
stdNumMonth // "1"
stdZeroMonth // "01"
stdLongWeekDay // "Monday"
stdWeekDay // "Mon"
stdDay // "2"
stdUnderDay // "_2"
stdZeroDay // "02"
stdUnderYearDay // "__2"
stdZeroYearDay // "002"
stdHour = iota + stdNeedClock // "15"
stdHour12 // "3"
stdZeroHour12 // "03"
stdMinute // "4"
stdZeroMinute // "04"
stdSecond // "5"
stdZeroSecond // "05"
stdLongYear = iota + stdNeedDate // "2006"
stdYear // "06"
stdPM = iota + stdNeedClock // "PM"
stdpm // "pm"
stdTZ = iota // "MST"
stdISO8601TZ // "Z0700" // prints Z for UTC
stdISO8601SecondsTZ // "Z070000"
stdISO8601ShortTZ // "Z07"
stdISO8601ColonTZ // "Z07:00" // prints Z for UTC
stdISO8601ColonSecondsTZ // "Z07:00:00"
stdNumTZ // "-0700" // always numeric
stdNumSecondsTz // "-070000"
stdNumShortTZ // "-07" // always numeric
stdNumColonTZ // "-07:00" // always numeric
stdNumColonSecondsTZ // "-07:00:00"
stdFracSecond0 // ".0", ".00", ... , trailing zeros included
stdFracSecond9 // ".9", ".99", ..., trailing zeros omitted
stdNeedDate = 1 << 8 // need month, day, year
stdNeedClock = 2 << 8 // need hour, minute, second
stdArgShift = 16 // extra argument in high bits, above low stdArgShift
stdSeparatorShift = 28 // extra argument in high 4 bits for fractional second separators
stdMask = 1<<stdArgShift - 1 // mask out argument
)
// std0x records the std values for "01", "02", ..., "06".
var std0x = [...]int{stdZeroMonth, stdZeroDay, stdZeroHour12, stdZeroMinute, stdZeroSecond, stdYear}
// startsWithLowerCase reports whether the string has a lower-case letter at the beginning.
// Its purpose is to prevent matching strings like "Month" when looking for "Mon".
func startsWithLowerCase(str string) bool {
if len(str) == 0 {
return false
}
c := str[0]
return 'a' <= c && c <= 'z'
}
// nextStdChunk finds the first occurrence of a std string in
// layout and returns the text before, the std string, and the text after.
func nextStdChunk(layout string) (prefix string, std int, suffix string) {
for i := 0; i < len(layout); i++ {
switch c := int(layout[i]); c {
case 'J': // January, Jan
if len(layout) >= i+3 && layout[i:i+3] == "Jan" {
if len(layout) >= i+7 && layout[i:i+7] == "January" {
return layout[0:i], stdLongMonth, layout[i+7:]
}
if !startsWithLowerCase(layout[i+3:]) {
return layout[0:i], stdMonth, layout[i+3:]
}
}
case 'M': // Monday, Mon, MST
if len(layout) >= i+3 {
if layout[i:i+3] == "Mon" {
if len(layout) >= i+6 && layout[i:i+6] == "Monday" {
return layout[0:i], stdLongWeekDay, layout[i+6:]
}
if !startsWithLowerCase(layout[i+3:]) {
return layout[0:i], stdWeekDay, layout[i+3:]
}
}
if layout[i:i+3] == "MST" {
return layout[0:i], stdTZ, layout[i+3:]
}
}
case '0': // 01, 02, 03, 04, 05, 06, 002
if len(layout) >= i+2 && '1' <= layout[i+1] && layout[i+1] <= '6' {
return layout[0:i], std0x[layout[i+1]-'1'], layout[i+2:]
}
if len(layout) >= i+3 && layout[i+1] == '0' && layout[i+2] == '2' {
return layout[0:i], stdZeroYearDay, layout[i+3:]
}
case '1': // 15, 1
if len(layout) >= i+2 && layout[i+1] == '5' {
return layout[0:i], stdHour, layout[i+2:]
}
return layout[0:i], stdNumMonth, layout[i+1:]
case '2': // 2006, 2
if len(layout) >= i+4 && layout[i:i+4] == "2006" {
return layout[0:i], stdLongYear, layout[i+4:]
}
return layout[0:i], stdDay, layout[i+1:]
case '_': // _2, _2006, __2
if len(layout) >= i+2 && layout[i+1] == '2' {
//_2006 is really a literal _, followed by stdLongYear
if len(layout) >= i+5 && layout[i+1:i+5] == "2006" {
return layout[0 : i+1], stdLongYear, layout[i+5:]
}
return layout[0:i], stdUnderDay, layout[i+2:]
}
if len(layout) >= i+3 && layout[i+1] == '_' && layout[i+2] == '2' {
return layout[0:i], stdUnderYearDay, layout[i+3:]
}
case '3':
return layout[0:i], stdHour12, layout[i+1:]
case '4':
return layout[0:i], stdMinute, layout[i+1:]
case '5':
return layout[0:i], stdSecond, layout[i+1:]
case 'P': // PM
if len(layout) >= i+2 && layout[i+1] == 'M' {
return layout[0:i], stdPM, layout[i+2:]
}
case 'p': // pm
if len(layout) >= i+2 && layout[i+1] == 'm' {
return layout[0:i], stdpm, layout[i+2:]
}
case '-': // -070000, -07:00:00, -0700, -07:00, -07
if len(layout) >= i+7 && layout[i:i+7] == "-070000" {
return layout[0:i], stdNumSecondsTz, layout[i+7:]
}
if len(layout) >= i+9 && layout[i:i+9] == "-07:00:00" {
return layout[0:i], stdNumColonSecondsTZ, layout[i+9:]
}
if len(layout) >= i+5 && layout[i:i+5] == "-0700" {
return layout[0:i], stdNumTZ, layout[i+5:]
}
if len(layout) >= i+6 && layout[i:i+6] == "-07:00" {
return layout[0:i], stdNumColonTZ, layout[i+6:]
}
if len(layout) >= i+3 && layout[i:i+3] == "-07" {
return layout[0:i], stdNumShortTZ, layout[i+3:]
}
case 'Z': // Z070000, Z07:00:00, Z0700, Z07:00,
if len(layout) >= i+7 && layout[i:i+7] == "Z070000" {
return layout[0:i], stdISO8601SecondsTZ, layout[i+7:]
}
if len(layout) >= i+9 && layout[i:i+9] == "Z07:00:00" {
return layout[0:i], stdISO8601ColonSecondsTZ, layout[i+9:]
}
if len(layout) >= i+5 && layout[i:i+5] == "Z0700" {
return layout[0:i], stdISO8601TZ, layout[i+5:]
}
if len(layout) >= i+6 && layout[i:i+6] == "Z07:00" {
return layout[0:i], stdISO8601ColonTZ, layout[i+6:]
}
if len(layout) >= i+3 && layout[i:i+3] == "Z07" {
return layout[0:i], stdISO8601ShortTZ, layout[i+3:]
}
case '.', ',': // ,000, or .000, or ,999, or .999 - repeated digits for fractional seconds.
if i+1 < len(layout) && (layout[i+1] == '0' || layout[i+1] == '9') {
ch := layout[i+1]
j := i + 1
for j < len(layout) && layout[j] == ch {
j++
}
// String of digits must end here - only fractional second is all digits.
if !isDigit(layout, j) {
code := stdFracSecond0
if layout[i+1] == '9' {
code = stdFracSecond9
}
std := stdFracSecond(code, j-(i+1), c)
return layout[0:i], std, layout[j:]
}
}
}
}
return layout, 0, ""
}
var longDayNames = []string{
"Sunday",
"Monday",
"Tuesday",
"Wednesday",
"Thursday",
"Friday",
"Saturday",
}
var shortDayNames = []string{
"Sun",
"Mon",
"Tue",
"Wed",
"Thu",
"Fri",
"Sat",
}
var shortMonthNames = []string{
"Jan",
"Feb",
"Mar",
"Apr",
"May",
"Jun",
"Jul",
"Aug",
"Sep",
"Oct",
"Nov",
"Dec",
}
var longMonthNames = []string{
"January",
"February",
"March",
"April",
"May",
"June",
"July",
"August",
"September",
"October",
"November",
"December",
}
// match reports whether s1 and s2 match ignoring case.
// It is assumed s1 and s2 are the same length.
func match(s1, s2 string) bool {
for i := 0; i < len(s1); i++ {
c1 := s1[i]
c2 := s2[i]
if c1 != c2 {
// Switch to lower-case; 'a'-'A' is known to be a single bit.
c1 |= 'a' - 'A'
c2 |= 'a' - 'A'
if c1 != c2 || c1 < 'a' || c1 > 'z' {
return false
}
}
}
return true
}
func lookup(tab []string, val string) (int, string, error) {
for i, v := range tab {
if len(val) >= len(v) && match(val[0:len(v)], v) {
return i, val[len(v):], nil
}
}
return -1, val, errBad
}
// appendInt appends the decimal form of x to b and returns the result.
// If the decimal form (excluding sign) is shorter than width, the result is padded with leading 0's.
// Duplicates functionality in strconv, but avoids dependency.
func appendInt(b []byte, x int, width int) []byte {
u := uint(x)
if x < 0 {
b = append(b, '-')
u = uint(-x)
}
// Assemble decimal in reverse order.
var buf [20]byte
i := len(buf)
for u >= 10 {
i--
q := u / 10
buf[i] = byte('0' + u - q*10)
u = q
}
i--
buf[i] = byte('0' + u)
// Add 0-padding.
for w := len(buf) - i; w < width; w++ {
b = append(b, '0')
}
return append(b, buf[i:]...)
}
// Never printed, just needs to be non-nil for return by atoi.
var atoiError = errors.New("time: invalid number")
// Duplicates functionality in strconv, but avoids dependency.
func atoi(s string) (x int, err error) {
neg := false
if s != "" && (s[0] == '-' || s[0] == '+') {
neg = s[0] == '-'
s = s[1:]
}
q, rem, err := leadingInt(s)
x = int(q)
if err != nil || rem != "" {
return 0, atoiError
}
if neg {
x = -x
}
return x, nil
}
// The "std" value passed to formatNano contains two packed fields: the number of
// digits after the decimal and the separator character (period or comma).
// These functions pack and unpack that variable.
func stdFracSecond(code, n, c int) int {
// Use 0xfff to make the failure case even more absurd.
if c == '.' {
return code | ((n & 0xfff) << stdArgShift)
}
return code | ((n & 0xfff) << stdArgShift) | 1<<stdSeparatorShift
}
func digitsLen(std int) int {
return (std >> stdArgShift) & 0xfff
}
func separator(std int) byte {
if (std >> stdSeparatorShift) == 0 {
return '.'
}
return ','
}
// formatNano appends a fractional second, as nanoseconds, to b
// and returns the result.
func formatNano(b []byte, nanosec uint, std int) []byte {
var (
n = digitsLen(std)
separator = separator(std)
trim = std&stdMask == stdFracSecond9
)
u := nanosec
var buf [9]byte
for start := len(buf); start > 0; {
start--
buf[start] = byte(u%10 + '0')
u /= 10
}
if n > 9 {
n = 9
}
if trim {
for n > 0 && buf[n-1] == '0' {
n--
}
if n == 0 {
return b
}
}
b = append(b, separator)
return append(b, buf[:n]...)
}
// String returns the time formatted using the format string
//
// "2006-01-02 15:04:05.999999999 -0700 MST"
//
// If the time has a monotonic clock reading, the returned string
// includes a final field "m=±<value>", where value is the monotonic
// clock reading formatted as a decimal number of seconds.
//
// The returned string is meant for debugging; for a stable serialized
// representation, use t.MarshalText, t.MarshalBinary, or t.Format
// with an explicit format string.
func (t Time) String() string {
s := t.Format("2006-01-02 15:04:05.999999999 -0700 MST")
// Format monotonic clock reading as m=±ddd.nnnnnnnnn.
if t.wall&hasMonotonic != 0 {
m2 := uint64(t.ext)
sign := byte('+')
if t.ext < 0 {
sign = '-'
m2 = -m2
}
m1, m2 := m2/1e9, m2%1e9
m0, m1 := m1/1e9, m1%1e9
buf := make([]byte, 0, 24)
buf = append(buf, " m="...)
buf = append(buf, sign)
wid := 0
if m0 != 0 {
buf = appendInt(buf, int(m0), 0)
wid = 9
}
buf = appendInt(buf, int(m1), wid)
buf = append(buf, '.')
buf = appendInt(buf, int(m2), 9)
s += string(buf)
}
return s
}
// GoString implements fmt.GoStringer and formats t to be printed in Go source
// code.
func (t Time) GoString() string {
buf := make([]byte, 0, 70)
buf = append(buf, "time.Date("...)
buf = appendInt(buf, t.Year(), 0)
month := t.Month()
if January <= month && month <= December {
buf = append(buf, ", time."...)
buf = append(buf, t.Month().String()...)
} else {
// It's difficult to construct a time.Time with a date outside the
// standard range but we might as well try to handle the case.
buf = appendInt(buf, int(month), 0)
}
buf = append(buf, ", "...)
buf = appendInt(buf, t.Day(), 0)
buf = append(buf, ", "...)
buf = appendInt(buf, t.Hour(), 0)
buf = append(buf, ", "...)
buf = appendInt(buf, t.Minute(), 0)
buf = append(buf, ", "...)
buf = appendInt(buf, t.Second(), 0)
buf = append(buf, ", "...)
buf = appendInt(buf, t.Nanosecond(), 0)
buf = append(buf, ", "...)
switch loc := t.Location(); loc {
case UTC, nil:
buf = append(buf, "time.UTC"...)
case Local:
buf = append(buf, "time.Local"...)
default:
// there are several options for how we could display this, none of
// which are great:
//
// - use Location(loc.name), which is not technically valid syntax
// - use LoadLocation(loc.name), which will cause a syntax error when
// embedded and also would require us to escape the string without
// importing fmt or strconv
// - try to use FixedZone, which would also require escaping the name
// and would represent e.g. "America/Los_Angeles" daylight saving time
// shifts inaccurately
// - use the pointer format, which is no worse than you'd get with the
// old fmt.Sprintf("%#v", t) format.
//
// Of these, Location(loc.name) is the least disruptive. This is an edge
// case we hope not to hit too often.
buf = append(buf, `time.Location(`...)
buf = append(buf, []byte(quote(loc.name))...)
buf = append(buf, `)`...)
}
buf = append(buf, ')')
return string(buf)
}
// Format returns a textual representation of the time value formatted according
// to the layout defined by the argument. See the documentation for the
// constant called Layout to see how to represent the layout format.
//
// The executable example for Time.Format demonstrates the working
// of the layout string in detail and is a good reference.
func (t Time) Format(layout string) string {
const bufSize = 64
var b []byte
max := len(layout) + 10
if max < bufSize {
var buf [bufSize]byte
b = buf[:0]
} else {
b = make([]byte, 0, max)
}
b = t.AppendFormat(b, layout)
return string(b)
}
// AppendFormat is like Format but appends the textual
// representation to b and returns the extended buffer.
func (t Time) AppendFormat(b []byte, layout string) []byte {
var (
name, offset, abs = t.locabs()
year int = -1
month Month
day int
yday int
hour int = -1
min int
sec int
)
// Each iteration generates one std value.
for layout != "" {
prefix, std, suffix := nextStdChunk(layout)
if prefix != "" {
b = append(b, prefix...)
}
if std == 0 {
break
}
layout = suffix
// Compute year, month, day if needed.
if year < 0 && std&stdNeedDate != 0 {
year, month, day, yday = absDate(abs, true)
yday++
}
// Compute hour, minute, second if needed.
if hour < 0 && std&stdNeedClock != 0 {
hour, min, sec = absClock(abs)
}
switch std & stdMask {
case stdYear:
y := year
if y < 0 {
y = -y
}
b = appendInt(b, y%100, 2)
case stdLongYear:
b = appendInt(b, year, 4)
case stdMonth:
b = append(b, month.String()[:3]...)
case stdLongMonth:
m := month.String()
b = append(b, m...)
case stdNumMonth:
b = appendInt(b, int(month), 0)
case stdZeroMonth:
b = appendInt(b, int(month), 2)
case stdWeekDay:
b = append(b, absWeekday(abs).String()[:3]...)
case stdLongWeekDay:
s := absWeekday(abs).String()
b = append(b, s...)
case stdDay:
b = appendInt(b, day, 0)
case stdUnderDay:
if day < 10 {
b = append(b, ' ')
}
b = appendInt(b, day, 0)
case stdZeroDay:
b = appendInt(b, day, 2)
case stdUnderYearDay:
if yday < 100 {
b = append(b, ' ')
if yday < 10 {
b = append(b, ' ')
}
}
b = appendInt(b, yday, 0)
case stdZeroYearDay:
b = appendInt(b, yday, 3)
case stdHour:
b = appendInt(b, hour, 2)
case stdHour12:
// Noon is 12PM, midnight is 12AM.
hr := hour % 12
if hr == 0 {
hr = 12
}
b = appendInt(b, hr, 0)
case stdZeroHour12:
// Noon is 12PM, midnight is 12AM.
hr := hour % 12
if hr == 0 {
hr = 12
}
b = appendInt(b, hr, 2)
case stdMinute:
b = appendInt(b, min, 0)
case stdZeroMinute:
b = appendInt(b, min, 2)
case stdSecond:
b = appendInt(b, sec, 0)
case stdZeroSecond:
b = appendInt(b, sec, 2)
case stdPM:
if hour >= 12 {
b = append(b, "PM"...)
} else {
b = append(b, "AM"...)
}
case stdpm:
if hour >= 12 {
b = append(b, "pm"...)
} else {
b = append(b, "am"...)
}
case stdISO8601TZ, stdISO8601ColonTZ, stdISO8601SecondsTZ, stdISO8601ShortTZ, stdISO8601ColonSecondsTZ, stdNumTZ, stdNumColonTZ, stdNumSecondsTz, stdNumShortTZ, stdNumColonSecondsTZ:
// Ugly special case. We cheat and take the "Z" variants
// to mean "the time zone as formatted for ISO 8601".
if offset == 0 && (std == stdISO8601TZ || std == stdISO8601ColonTZ || std == stdISO8601SecondsTZ || std == stdISO8601ShortTZ || std == stdISO8601ColonSecondsTZ) {
b = append(b, 'Z')
break
}
zone := offset / 60 // convert to minutes
absoffset := offset
if zone < 0 {
b = append(b, '-')
zone = -zone
absoffset = -absoffset
} else {
b = append(b, '+')
}
b = appendInt(b, zone/60, 2)
if std == stdISO8601ColonTZ || std == stdNumColonTZ || std == stdISO8601ColonSecondsTZ || std == stdNumColonSecondsTZ {
b = append(b, ':')
}
if std != stdNumShortTZ && std != stdISO8601ShortTZ {
b = appendInt(b, zone%60, 2)
}
// append seconds if appropriate
if std == stdISO8601SecondsTZ || std == stdNumSecondsTz || std == stdNumColonSecondsTZ || std == stdISO8601ColonSecondsTZ {
if std == stdNumColonSecondsTZ || std == stdISO8601ColonSecondsTZ {
b = append(b, ':')
}
b = appendInt(b, absoffset%60, 2)
}
case stdTZ:
if name != "" {
b = append(b, name...)
break
}
// No time zone known for this time, but we must print one.
// Use the -0700 format.
zone := offset / 60 // convert to minutes
if zone < 0 {
b = append(b, '-')
zone = -zone
} else {
b = append(b, '+')
}
b = appendInt(b, zone/60, 2)
b = appendInt(b, zone%60, 2)
case stdFracSecond0, stdFracSecond9:
b = formatNano(b, uint(t.Nanosecond()), std)
}
}
return b
}
var errBad = errors.New("bad value for field") // placeholder not passed to user
// ParseError describes a problem parsing a time string.
type ParseError struct {
Layout string
Value string
LayoutElem string
ValueElem string
Message string
}
// These are borrowed from unicode/utf8 and strconv and replicate behavior in
// that package, since we can't take a dependency on either.
const (
lowerhex = "0123456789abcdef"
runeSelf = 0x80
runeError = '\uFFFD'
)
func quote(s string) string {
buf := make([]byte, 1, len(s)+2) // slice will be at least len(s) + quotes
buf[0] = '"'
for i, c := range s {
if c >= runeSelf || c < ' ' {
// This means you are asking us to parse a time.Duration or
// time.Location with unprintable or non-ASCII characters in it.
// We don't expect to hit this case very often. We could try to
// reproduce strconv.Quote's behavior with full fidelity but
// given how rarely we expect to hit these edge cases, speed and
// conciseness are better.
var width int
if c == runeError {
width = 1
if i+2 < len(s) && s[i:i+3] == string(runeError) {
width = 3
}
} else {
width = len(string(c))
}
for j := 0; j < width; j++ {
buf = append(buf, `\x`...)
buf = append(buf, lowerhex[s[i+j]>>4])
buf = append(buf, lowerhex[s[i+j]&0xF])
}
} else {
if c == '"' || c == '\\' {
buf = append(buf, '\\')
}
buf = append(buf, string(c)...)
}
}
buf = append(buf, '"')
return string(buf)
}
// Error returns the string representation of a ParseError.
func (e *ParseError) Error() string {
if e.Message == "" {
return "parsing time " +
quote(e.Value) + " as " +
quote(e.Layout) + ": cannot parse " +
quote(e.ValueElem) + " as " +
quote(e.LayoutElem)
}
return "parsing time " +
quote(e.Value) + e.Message
}
// isDigit reports whether s[i] is in range and is a decimal digit.
func isDigit(s string, i int) bool {
if len(s) <= i {
return false
}
c := s[i]
return '0' <= c && c <= '9'
}
// getnum parses s[0:1] or s[0:2] (fixed forces s[0:2])
// as a decimal integer and returns the integer and the
// remainder of the string.
func getnum(s string, fixed bool) (int, string, error) {
if !isDigit(s, 0) {
return 0, s, errBad
}
if !isDigit(s, 1) {
if fixed {
return 0, s, errBad
}
return int(s[0] - '0'), s[1:], nil
}
return int(s[0]-'0')*10 + int(s[1]-'0'), s[2:], nil
}
// getnum3 parses s[0:1], s[0:2], or s[0:3] (fixed forces s[0:3])
// as a decimal integer and returns the integer and the remainder
// of the string.
func getnum3(s string, fixed bool) (int, string, error) {
var n, i int
for i = 0; i < 3 && isDigit(s, i); i++ {
n = n*10 + int(s[i]-'0')
}
if i == 0 || fixed && i != 3 {
return 0, s, errBad
}
return n, s[i:], nil
}
func cutspace(s string) string {
for len(s) > 0 && s[0] == ' ' {
s = s[1:]
}
return s
}
// skip removes the given prefix from value,
// treating runs of space characters as equivalent.
func skip(value, prefix string) (string, error) {
for len(prefix) > 0 {
if prefix[0] == ' ' {
if len(value) > 0 && value[0] != ' ' {
return value, errBad
}
prefix = cutspace(prefix)
value = cutspace(value)
continue
}
if len(value) == 0 || value[0] != prefix[0] {
return value, errBad
}
prefix = prefix[1:]
value = value[1:]
}
return value, nil
}
// Parse parses a formatted string and returns the time value it represents.
// See the documentation for the constant called Layout to see how to
// represent the format. The second argument must be parseable using
// the format string (layout) provided as the first argument.
//
// The example for Time.Format demonstrates the working of the layout string
// in detail and is a good reference.
//
// When parsing (only), the input may contain a fractional second
// field immediately after the seconds field, even if the layout does not
// signify its presence. In that case either a comma or a decimal point
// followed by a maximal series of digits is parsed as a fractional second.
// Fractional seconds are truncated to nanosecond precision.
//
// Elements omitted from the layout are assumed to be zero or, when
// zero is impossible, one, so parsing "3:04pm" returns the time
// corresponding to Jan 1, year 0, 15:04:00 UTC (note that because the year is
// 0, this time is before the zero Time).
// Years must be in the range 0000..9999. The day of the week is checked
// for syntax but it is otherwise ignored.
//
// For layouts specifying the two-digit year 06, a value NN >= 69 will be treated
// as 19NN and a value NN < 69 will be treated as 20NN.
//
// The remainder of this comment describes the handling of time zones.
//
// In the absence of a time zone indicator, Parse returns a time in UTC.
//
// When parsing a time with a zone offset like -0700, if the offset corresponds
// to a time zone used by the current location (Local), then Parse uses that
// location and zone in the returned time. Otherwise it records the time as
// being in a fabricated location with time fixed at the given zone offset.
//
// When parsing a time with a zone abbreviation like MST, if the zone abbreviation
// has a defined offset in the current location, then that offset is used.
// The zone abbreviation "UTC" is recognized as UTC regardless of location.
// If the zone abbreviation is unknown, Parse records the time as being
// in a fabricated location with the given zone abbreviation and a zero offset.
// This choice means that such a time can be parsed and reformatted with the
// same layout losslessly, but the exact instant used in the representation will
// differ by the actual zone offset. To avoid such problems, prefer time layouts
// that use a numeric zone offset, or use ParseInLocation.
func Parse(layout, value string) (Time, error) {
return parse(layout, value, UTC, Local)
}
// ParseInLocation is like Parse but differs in two important ways.
// First, in the absence of time zone information, Parse interprets a time as UTC;
// ParseInLocation interprets the time as in the given location.
// Second, when given a zone offset or abbreviation, Parse tries to match it
// against the Local location; ParseInLocation uses the given location.
func ParseInLocation(layout, value string, loc *Location) (Time, error) {
return parse(layout, value, loc, loc)
}
func parse(layout, value string, defaultLocation, local *Location) (Time, error) {
alayout, avalue := layout, value
rangeErrString := "" // set if a value is out of range
amSet := false // do we need to subtract 12 from the hour for midnight?
pmSet := false // do we need to add 12 to the hour?
// Time being constructed.
var (
year int
month int = -1
day int = -1
yday int = -1
hour int
min int
sec int
nsec int
z *Location
zoneOffset int = -1
zoneName string
)
// Each iteration processes one std value.
for {
var err error
prefix, std, suffix := nextStdChunk(layout)
stdstr := layout[len(prefix) : len(layout)-len(suffix)]
value, err = skip(value, prefix)
if err != nil {
return Time{}, &ParseError{alayout, avalue, prefix, value, ""}
}
if std == 0 {
if len(value) != 0 {
return Time{}, &ParseError{alayout, avalue, "", value, ": extra text: " + quote(value)}
}