blob: c04325126625ed948c412331d5f59c90dee493fc [file] [log] [blame]
package time
import (
"bytes"
"os"
"strconv"
)
const (
numeric = iota
alphabetic
separator
plus
minus
)
// These are predefined layouts for use in Time.Format.
// The standard time used in the layouts is:
// Mon Jan 2 15:04:05 MST 2006 (MST is GMT-0700)
// which is Unix time 1136243045.
// (Think of it as 01/02 03:04:05PM '06 -0700.)
// An underscore _ represents a space that
// may be replaced by a digit if the following number
// (a day) has two digits; for compatibility with
// fixed-width Unix time formats.
//
// Numeric time zone offsets format as follows:
// -0700 ±hhmm
// -07:00 ±hh:mm
// 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
const (
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 1504 MST"
// RFC822 with Zulu time.
RFC822Z = "02 Jan 06 1504 -0700"
RFC850 = "Monday, 02-Jan-06 15:04:05 MST"
RFC1123 = "Mon, 02 Jan 2006 15:04:05 MST"
Kitchen = "3:04PM"
RFC3339 = "2006-01-02T15:04:05Z07:00"
)
const (
stdLongMonth = "January"
stdMonth = "Jan"
stdNumMonth = "1"
stdZeroMonth = "01"
stdLongWeekDay = "Monday"
stdWeekDay = "Mon"
stdDay = "2"
stdUnderDay = "_2"
stdZeroDay = "02"
stdHour = "15"
stdHour12 = "3"
stdZeroHour12 = "03"
stdMinute = "4"
stdZeroMinute = "04"
stdSecond = "5"
stdZeroSecond = "05"
stdLongYear = "2006"
stdYear = "06"
stdPM = "PM"
stdpm = "pm"
stdTZ = "MST"
stdISO8601TZ = "Z0700" // prints Z for UTC
stdISO8601ColonTZ = "Z07:00" // prints Z for UTC
stdNumTZ = "-0700" // always numeric
stdNumColonTZ = "-07:00" // always numeric
)
// 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, std, suffix string) {
for i := 0; i < len(layout); i++ {
switch layout[i] {
case 'J': // January, Jan
if len(layout) >= i+7 && layout[i:i+7] == stdLongMonth {
return layout[0:i], stdLongMonth, layout[i+7:]
}
if len(layout) >= i+3 && layout[i:i+3] == stdMonth {
return layout[0:i], stdMonth, layout[i+3:]
}
case 'M': // Monday, Mon, MST
if len(layout) >= i+6 && layout[i:i+6] == stdLongWeekDay {
return layout[0:i], stdLongWeekDay, layout[i+6:]
}
if len(layout) >= i+3 {
if layout[i:i+3] == stdWeekDay {
return layout[0:i], stdWeekDay, layout[i+3:]
}
if layout[i:i+3] == stdTZ {
return layout[0:i], stdTZ, layout[i+3:]
}
}
case '0': // 01, 02, 03, 04, 05, 06
if len(layout) >= i+2 && '1' <= layout[i+1] && layout[i+1] <= '6' {
return layout[0:i], layout[i : i+2], layout[i+2:]
}
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] == stdLongYear {
return layout[0:i], stdLongYear, layout[i+4:]
}
return layout[0:i], stdDay, layout[i+1:]
case '_': // _2
if len(layout) >= i+2 && layout[i+1] == '2' {
return layout[0:i], stdUnderDay, layout[i+2:]
}
case '3', '4', '5': // 3, 4, 5
return layout[0:i], layout[i : i+1], layout[i+1:]
case 'P': // PM
if len(layout) >= i+2 && layout[i+1] == 'M' {
return layout[0:i], layout[i : i+2], layout[i+2:]
}
case 'p': // pm
if len(layout) >= i+2 && layout[i+1] == 'm' {
return layout[0:i], layout[i : i+2], layout[i+2:]
}
case '-': // -0700, -07:00
if len(layout) >= i+5 && layout[i:i+5] == stdNumTZ {
return layout[0:i], layout[i : i+5], layout[i+5:]
}
if len(layout) >= i+6 && layout[i:i+6] == stdNumColonTZ {
return layout[0:i], layout[i : i+6], layout[i+6:]
}
case 'Z': // Z0700, Z07:00
if len(layout) >= i+5 && layout[i:i+5] == stdISO8601TZ {
return layout[0:i], layout[i : i+5], layout[i+5:]
}
if len(layout) >= i+6 && layout[i:i+6] == stdISO8601ColonTZ {
return layout[0:i], layout[i : i+6], layout[i+6:]
}
}
}
return layout, "", ""
}
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",
}
func lookup(tab []string, val string) (int, string, os.Error) {
for i, v := range tab {
if len(val) >= len(v) && val[0:len(v)] == v {
return i, val[len(v):], nil
}
}
return -1, val, errBad
}
func pad(i int, padding string) string {
s := strconv.Itoa(i)
if i < 10 {
s = padding + s
}
return s
}
func zeroPad(i int) string { return pad(i, "0") }
// 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
// the time to be formatted. Predefined layouts ANSIC, UnixDate,
// RFC3339 and others describe standard representations.
func (t *Time) Format(layout string) string {
b := new(bytes.Buffer)
// Each iteration generates one std value.
for {
prefix, std, suffix := nextStdChunk(layout)
b.WriteString(prefix)
if std == "" {
break
}
var p string
switch std {
case stdYear:
p = strconv.Itoa64(t.Year % 100)
case stdLongYear:
p = strconv.Itoa64(t.Year)
case stdMonth:
p = shortMonthNames[t.Month]
case stdLongMonth:
p = longMonthNames[t.Month]
case stdNumMonth:
p = strconv.Itoa(t.Month)
case stdZeroMonth:
p = zeroPad(t.Month)
case stdWeekDay:
p = shortDayNames[t.Weekday]
case stdLongWeekDay:
p = longDayNames[t.Weekday]
case stdDay:
p = strconv.Itoa(t.Day)
case stdUnderDay:
p = pad(t.Day, " ")
case stdZeroDay:
p = zeroPad(t.Day)
case stdHour:
p = zeroPad(t.Hour)
case stdHour12:
p = strconv.Itoa(t.Hour % 12)
case stdZeroHour12:
p = zeroPad(t.Hour % 12)
case stdMinute:
p = strconv.Itoa(t.Minute)
case stdZeroMinute:
p = zeroPad(t.Minute)
case stdSecond:
p = strconv.Itoa(t.Second)
case stdZeroSecond:
p = zeroPad(t.Second)
case stdISO8601TZ, stdISO8601ColonTZ, stdNumTZ, stdNumColonTZ:
// Ugly special case. We cheat and take the "Z" variants
// to mean "the time zone as formatted for ISO 8601".
if t.ZoneOffset == 0 && std[0] == 'Z' {
p = "Z"
break
}
zone := t.ZoneOffset / 60 // convert to minutes
if zone < 0 {
p = "-"
zone = -zone
} else {
p = "+"
}
p += zeroPad(zone / 60)
if std == stdISO8601ColonTZ || std == stdNumColonTZ {
p += ":"
}
p += zeroPad(zone % 60)
case stdPM:
if t.Hour >= 12 {
p = "PM"
} else {
p = "AM"
}
case stdpm:
if t.Hour >= 12 {
p = "pm"
} else {
p = "am"
}
case stdTZ:
if t.Zone != "" {
p = t.Zone
} else {
// No time zone known for this time, but we must print one.
// Use the -0700 format.
zone := t.ZoneOffset / 60 // convert to minutes
if zone < 0 {
p = "-"
zone = -zone
} else {
p = "+"
}
p += zeroPad(zone / 60)
p += zeroPad(zone % 60)
}
}
b.WriteString(p)
layout = suffix
}
return b.String()
}
// String returns a Unix-style representation of the time value.
func (t *Time) String() string { return t.Format(UnixDate) }
var errBad = os.ErrorString("bad") // just a marker; not returned to user
// ParseError describes a problem parsing a time string.
type ParseError struct {
Layout string
Value string
LayoutElem string
ValueElem string
Message string
}
// String is the string representation of a ParseError.
func (e *ParseError) String() string {
if e.Message == "" {
return "parsing time " +
strconv.Quote(e.Value) + " as " +
strconv.Quote(e.Layout) + ": cannot parse " +
strconv.Quote(e.ValueElem) + " as " +
strconv.Quote(e.LayoutElem)
}
return "parsing time " +
strconv.Quote(e.Value) + e.Message
}
// getnum parses s[0:1] or s[0:2] (fixed forces the latter)
// as a decimal integer and returns the integer and the
// remainder of the string.
func getnum(s string, fixed bool) (int, string, os.Error) {
if len(s) == 0 || s[0] < '0' || s[0] > '9' {
return 0, s, errBad
}
if len(s) == 1 || s[1] < '0' || s[1] > '9' {
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
}
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, os.Error) {
for len(prefix) > 0 {
if prefix[0] == ' ' {
if len(value) > 0 && value[0] != ' ' {
return "", errBad
}
prefix = cutspace(prefix)
value = cutspace(value)
continue
}
if len(value) == 0 || value[0] != prefix[0] {
return "", errBad
}
prefix = prefix[1:]
value = value[1:]
}
return value, nil
}
// Parse parses a formatted string and returns the time value it represents.
// The layout defines the format by showing the representation of a standard
// time, which is then used to describe the string to be parsed. Predefined
// layouts ANSIC, UnixDate, RFC3339 and others describe standard
// representations.
//
// Only those elements present in the value will be set in the returned time
// structure. Also, if the input string represents an inconsistent time
// (such as having the wrong day of the week), the returned value will also
// be inconsistent. In any case, the elements of the returned time will be
// sane: hours in 0..23, minutes in 0..59, day of month in 0..31, etc.
// Years must be in the range 0000..9999.
func Parse(alayout, avalue string) (*Time, os.Error) {
var t Time
rangeErrString := "" // set if a value is out of range
pmSet := false // do we need to add 12 to the hour?
layout, value := alayout, avalue
// Each iteration processes one std value.
for {
var err os.Error
prefix, std, suffix := nextStdChunk(layout)
value, err = skip(value, prefix)
if err != nil {
return nil, &ParseError{alayout, avalue, prefix, value, ""}
}
if len(std) == 0 {
if len(value) != 0 {
return nil, &ParseError{alayout, avalue, "", value, ": extra text: " + value}
}
break
}
layout = suffix
var p string
switch std {
case stdYear:
if len(value) < 2 {
err = errBad
break
}
p, value = value[0:2], value[2:]
t.Year, err = strconv.Atoi64(p)
if t.Year >= 69 { // Unix time starts Dec 31 1969 in some time zones
t.Year += 1900
} else {
t.Year += 2000
}
case stdLongYear:
if len(value) < 4 || value[0] < '0' || value[0] > '9' {
err = errBad
break
}
p, value = value[0:4], value[4:]
t.Year, err = strconv.Atoi64(p)
case stdMonth:
t.Month, value, err = lookup(shortMonthNames, value)
case stdLongMonth:
t.Month, value, err = lookup(longMonthNames, value)
case stdNumMonth, stdZeroMonth:
t.Month, value, err = getnum(value, std == stdZeroMonth)
if t.Month <= 0 || 12 < t.Month {
rangeErrString = "month"
}
case stdWeekDay:
t.Weekday, value, err = lookup(shortDayNames, value)
case stdLongWeekDay:
t.Weekday, value, err = lookup(longDayNames, value)
case stdDay, stdUnderDay, stdZeroDay:
if std == stdUnderDay && len(value) > 0 && value[0] == ' ' {
value = value[1:]
}
t.Day, value, err = getnum(value, std == stdZeroDay)
if t.Day < 0 || 31 < t.Day {
// TODO: be more thorough in date check?
rangeErrString = "day"
}
case stdHour:
t.Hour, value, err = getnum(value, false)
if t.Hour < 0 || 24 <= t.Hour {
rangeErrString = "hour"
}
case stdHour12, stdZeroHour12:
t.Hour, value, err = getnum(value, std == stdZeroHour12)
if t.Hour < 0 || 12 < t.Hour {
rangeErrString = "hour"
}
case stdMinute, stdZeroMinute:
t.Minute, value, err = getnum(value, std == stdZeroMinute)
if t.Minute < 0 || 60 <= t.Minute {
rangeErrString = "minute"
}
case stdSecond, stdZeroSecond:
t.Second, value, err = getnum(value, std == stdZeroSecond)
if t.Second < 0 || 60 <= t.Second {
rangeErrString = "second"
}
case stdISO8601TZ, stdISO8601ColonTZ, stdNumTZ, stdNumColonTZ:
if std[0] == 'Z' && len(value) >= 1 && value[0] == 'Z' {
value = value[1:]
t.Zone = "UTC"
break
}
var sign, hh, mm string
if std == stdISO8601ColonTZ || std == stdNumColonTZ {
if len(value) < 6 {
err = errBad
break
}
if value[3] != ':' {
err = errBad
break
}
sign, hh, mm, value = value[0:1], value[1:3], value[4:6], value[6:]
} else {
if len(value) < 5 {
err = errBad
break
}
sign, hh, mm, value = value[0:1], value[1:3], value[3:5], value[5:]
}
var hr, min int
hr, err = strconv.Atoi(hh)
if err != nil {
min, err = strconv.Atoi(mm)
}
t.ZoneOffset = (hr*60 + min) * 60 // offset is in seconds
switch sign[0] {
case '+':
case '-':
t.ZoneOffset = -t.ZoneOffset
default:
err = errBad
}
case stdPM:
if len(value) < 2 {
err = errBad
break
}
p, value = value[0:2], value[2:]
if p == "PM" {
pmSet = true
} else if p != "AM" {
err = errBad
}
case stdpm:
if len(value) < 2 {
err = errBad
break
}
p, value = value[0:2], value[2:]
if p == "pm" {
pmSet = true
} else if p != "am" {
err = errBad
}
case stdTZ:
// Does it look like a time zone?
if len(value) >= 3 && value[0:3] == "UTC" {
t.Zone, value = value[0:3], value[3:]
break
}
if len(value) >= 3 && value[2] == 'T' {
p, value = value[0:3], value[3:]
} else if len(value) >= 4 && value[3] == 'T' {
p, value = value[0:4], value[4:]
} else {
err = errBad
break
}
for i := 0; i < len(p); i++ {
if p[i] < 'A' || 'Z' < p[i] {
err = errBad
}
}
if err != nil {
break
}
// It's a valid format.
t.Zone = p
// Can we find its offset?
if offset, found := lookupByName(p); found {
t.ZoneOffset = offset
}
}
if rangeErrString != "" {
return nil, &ParseError{alayout, avalue, std, value, ": " + rangeErrString + " out of range"}
}
if err != nil {
return nil, &ParseError{alayout, avalue, std, value, ""}
}
}
if pmSet && t.Hour < 12 {
t.Hour += 12
}
return &t, nil
}