| // 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 and 002 are space-padded and zero-padded |
| // three-character day of year; there is no unpadded day of year format. |
| // |
| // A decimal point followed by one or more zeros represents a fractional |
| // second, printed to the given number of decimal places. |
| // Either 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 |
| 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) { |
| std := stdFracSecond0 |
| if layout[i+1] == '9' { |
| std = stdFracSecond9 |
| } |
| std |= (j - (i + 1)) << stdArgShift |
| 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 |
| } |
| |
| // formatNano appends a fractional second, as nanoseconds, to b |
| // and returns the result. |
| func formatNano(b []byte, nanosec uint, n int, trim bool) []byte { |
| 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, '.') |
| 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 |
| var buf []byte |
| 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 := []byte("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>>stdArgShift, std&stdMask == stdFracSecond9) |
| } |
| } |
| 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. |
| // |
| // 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)} |
| } |
| break |
| } |
| layout = suffix |
| var p string |
| switch std & stdMask { |
| case stdYear: |
| if len(value) < 2 { |
| err = errBad |
| break |
| } |
| hold := value |
| p, value = value[0:2], value[2:] |
| year, err = atoi(p) |
| if err != nil { |
| value = hold |
| } else if year >= 69 { // Unix time starts Dec 31 1969 in some time zones |
| year += 1900 |
| } else { |
| year += 2000 |
| } |
| case stdLongYear: |
| if len(value) < 4 || !isDigit(value, 0) { |
| err = errBad |
| break |
| } |
| p, value = value[0:4], value[4:] |
| year, err = atoi(p) |
| case stdMonth: |
| month, value, err = lookup(shortMonthNames, value) |
| month++ |
| case stdLongMonth: |
| month, value, err = lookup(longMonthNames, value) |
| month++ |
| case stdNumMonth, stdZeroMonth: |
| month, value, err = getnum(value, std == stdZeroMonth) |
| if err == nil && (month <= 0 || 12 < month) { |
| rangeErrString = "month" |
| } |
| case stdWeekDay: |
| // Ignore weekday except for error checking. |
| _, value, err = lookup(shortDayNames, value) |
| case stdLongWeekDay: |
| _, value, err = lookup(longDayNames, value) |
| case stdDay, stdUnderDay, stdZeroDay: |
| if std == stdUnderDay && len(value) > 0 && value[0] == ' ' { |
| value = value[1:] |
| } |
| day, value, err = getnum(value, std == stdZeroDay) |
| // Note that we allow any one- or two-digit day here. |
| // The month, day, year combination is validated after we've completed parsing. |
| case stdUnderYearDay, stdZeroYearDay: |
| for i := 0; i < 2; i++ { |
| if std == stdUnderYearDay && len(value) > 0 && value[0] == ' ' { |
| value = value[1:] |
| } |
| } |
| yday, value, err = getnum3(value, std == stdZeroYearDay) |
| // Note that we allow any one-, two-, or three-digit year-day here. |
| // The year-day, year combination is validated after we've completed parsing. |
| case stdHour: |
| hour, value, err = getnum(value, false) |
| if hour < 0 || 24 <= hour { |
| rangeErrString = "hour" |
| } |
| case stdHour12, stdZeroHour12: |
| hour, value, err = getnum(value, std == stdZeroHour12) |
| if hour < 0 || 12 < hour { |
| rangeErrString = "hour" |
| } |
| case stdMinute, stdZeroMinute: |
| min, value, err = getnum(value, std == stdZeroMinute) |
| if min < 0 || 60 <= min { |
| rangeErrString = "minute" |
| } |
| case stdSecond, stdZeroSecond: |
| sec, value, err = getnum(value, std == stdZeroSecond) |
| if sec < 0 || 60 <= sec { |
| rangeErrString = "second" |
| break |
| } |
| // Special case: do we have a fractional second but no |
| // fractional second in the format? |
| if len(value) >= 2 && commaOrPeriod(value[0]) && isDigit(value, 1) { |
| _, std, _ = nextStdChunk(layout) |
| std &= stdMask |
| if std == stdFracSecond0 || std == stdFracSecond9 { |
| // Fractional second in the layout; proceed normally |
| break |
| } |
| // No fractional second in the layout but we have one in the input. |
| n := 2 |
| for ; n < len(value) && isDigit(value, n); n++ { |
| } |
| nsec, rangeErrString, err = parseNanoseconds(value, n) |
| value = value[n:] |
| } |
| case stdPM: |
| if len(value) < 2 { |
| err = errBad |
| break |
| } |
| p, value = value[0:2], value[2:] |
| switch p { |
| case "PM": |
| pmSet = true |
| case "AM": |
| amSet = true |
| default: |
| err = errBad |
| } |
| case stdpm: |
| if len(value) < 2 { |
| err = errBad |
| break |
| } |
| p, value = value[0:2], value[2:] |
| switch p { |
| case "pm": |
| pmSet = true |
| case "am": |
| amSet = true |
| default: |
| err = errBad |
| } |
| case stdISO8601TZ, stdISO8601ColonTZ, stdISO8601SecondsTZ, stdISO8601ShortTZ, stdISO8601ColonSecondsTZ, stdNumTZ, stdNumShortTZ, stdNumColonTZ, stdNumSecondsTz, stdNumColonSecondsTZ: |
| if (std == stdISO8601TZ || std == stdISO8601ShortTZ || std == stdISO8601ColonTZ) && len(value) >= 1 && value[0] == 'Z' { |
| value = value[1:] |
| z = UTC |
| break |
| } |
| var sign, hour, min, seconds string |
| if std == stdISO8601ColonTZ || std == stdNumColonTZ { |
| if len(value) < 6 { |
| err = errBad |
| break |
| } |
| if value[3] != ':' { |
| err = errBad |
| break |
| } |
| sign, hour, min, seconds, value = value[0:1], value[1:3], value[4:6], "00", value[6:] |
| } else if std == stdNumShortTZ || std == stdISO8601ShortTZ { |
| if len(value) < 3 { |
| err = errBad |
| break |
| } |
| sign, hour, min, seconds, value = value[0:1], value[1:3], "00", "00", value[3:] |
| } else if std == stdISO8601ColonSecondsTZ || std == stdNumColonSecondsTZ { |
| if len(value) < 9 { |
| err = errBad |
| break |
| } |
| if value[3] != ':' || value[6] != ':' { |
| err = errBad |
| break |
| } |
| sign, hour, min, seconds, value = value[0:1], value[1:3], value[4:6], value[7:9], value[9:] |
| } else if std == stdISO8601SecondsTZ || std == stdNumSecondsTz { |
| if len(value) < 7 { |
| err = errBad |
| break |
| } |
| sign, hour, min, seconds, value = value[0:1], value[1:3], value[3:5], value[5:7], value[7:] |
| } else { |
| if len(value) < 5 { |
| err = errBad |
| break |
| } |
| sign, hour, min, seconds, value = value[0:1], value[1:3], value[3:5], "00", value[5:] |
| } |
| var hr, mm, ss int |
| hr, err = atoi(hour) |
| if err == nil { |
| mm, err = atoi(min) |
| } |
| if err == nil { |
| ss, err = atoi(seconds) |
| } |
| zoneOffset = (hr*60+mm)*60 + ss // offset is in seconds |
| switch sign[0] { |
| case '+': |
| case '-': |
| zoneOffset = -zoneOffset |
| default: |
| err = errBad |
| } |
| case stdTZ: |
| // Does it look like a time zone? |
| if len(value) >= 3 && value[0:3] == "UTC" { |
| z = UTC |
| value = value[3:] |
| break |
| } |
| n, ok := parseTimeZone(value) |
| if !ok { |
| err = errBad |
| break |
| } |
| zoneName, value = value[:n], value[n:] |
| |
| case stdFracSecond0: |
| // stdFracSecond0 requires the exact number of digits as specified in |
| // the layout. |
| ndigit := 1 + (std >> stdArgShift) |
| if len(value) < ndigit { |
| err = errBad |
| break |
| } |
| nsec, rangeErrString, err = parseNanoseconds(value, ndigit) |
| value = value[ndigit:] |
| |
| case stdFracSecond9: |
| if len(value) < 2 || !commaOrPeriod(value[0]) || value[1] < '0' || '9' < value[1] { |
| // Fractional second omitted. |
| break |
| } |
| // Take any number of digits, even more than asked for, |
| // because it is what the stdSecond case would do. |
| i := 0 |
| for i < 9 && i+1 < len(value) && '0' <= value[i+1] && value[i+1] <= '9' { |
| i++ |
| } |
| nsec, rangeErrString, err = parseNanoseconds(value, 1+i) |
| value = value[1+i:] |
| } |
| if rangeErrString != "" { |
| return Time{}, &ParseError{alayout, avalue, stdstr, value, ": " + rangeErrString + " out of range"} |
| } |
| if err != nil { |
| return Time{}, &ParseError{alayout, avalue, stdstr, value, ""} |
| } |
| } |
| if pmSet && hour < 12 { |
| hour += 12 |
| } else if amSet && hour == 12 { |
| hour = 0 |
| } |
| |
| // Convert yday to day, month. |
| if yday >= 0 { |
| var d int |
| var m int |
| if isLeap(year) { |
| if yday == 31+29 { |
| m = int(February) |
| d = 29 |
| } else if yday > 31+29 { |
| yday-- |
| } |
| } |
| if yday < 1 || yday > 365 { |
| return Time{}, &ParseError{alayout, avalue, "", value, ": day-of-year out of range"} |
| } |
| if m == 0 { |
| m = (yday-1)/31 + 1 |
| if int(daysBefore[m]) < yday { |
| m++ |
| } |
| d = yday - int(daysBefore[m-1]) |
| } |
| // If month, day already seen, yday's m, d must match. |
| // Otherwise, set them from m, d. |
| if month >= 0 && month != m { |
| return Time{}, &ParseError{alayout, avalue, "", value, ": day-of-year does not match month"} |
| } |
| month = m |
| if day >= 0 && day != d { |
| return Time{}, &ParseError{alayout, avalue, "", value, ": day-of-year does not match day"} |
| } |
| day = d |
| } else { |
| if month < 0 { |
| month = int(January) |
| } |
| if day < 0 { |
| day = 1 |
| } |
| } |
| |
| // Validate the day of the month. |
| if day < 1 || day > daysIn(Month(month), year) { |
| return Time{}, &ParseError{alayout, avalue, "", value, ": day out of range"} |
| } |
| |
| if z != nil { |
| return Date(year, Month(month), day, hour, min, sec, nsec, z), nil |
| } |
| |
| if zoneOffset != -1 { |
| t := Date(year, Month(month), day, hour, min, sec, nsec, UTC) |
| t.addSec(-int64(zoneOffset)) |
| |
| // Look for local zone with the given offset. |
| // If that zone was in effect at the given time, use it. |
| name, offset, _, _, _ := local.lookup(t.unixSec()) |
| if offset == zoneOffset && (zoneName == "" || name == zoneName) { |
| t.setLoc(local) |
| return t, nil |
| } |
| |
| // Otherwise create fake zone to record offset. |
| t.setLoc(FixedZone(zoneName, zoneOffset)) |
| return t, nil |
| } |
| |
| if zoneName != "" { |
| t := Date(year, Month(month), day, hour, min, sec, nsec, UTC) |
| // Look for local zone with the given offset. |
| // If that zone was in effect at the given time, use it. |
| offset, ok := local.lookupName(zoneName, t.unixSec()) |
| if ok { |
| t.addSec(-int64(offset)) |
| t.setLoc(local) |
| return t, nil |
| } |
| |
| // Otherwise, create fake zone with unknown offset. |
| if len(zoneName) > 3 && zoneName[:3] == "GMT" { |
| offset, _ = atoi(zoneName[3:]) // Guaranteed OK by parseGMT. |
| offset *= 3600 |
| } |
| t.setLoc(FixedZone(zoneName, offset)) |
| return t, nil |
| } |
| |
| // Otherwise, fall back to default. |
| return Date(year, Month(month), day, hour, min, sec, nsec, defaultLocation), nil |
| } |
| |
| // parseTimeZone parses a time zone string and returns its length. Time zones |
| // are human-generated and unpredictable. We can't do precise error checking. |
| // On the other hand, for a correct parse there must be a time zone at the |
| // beginning of the string, so it's almost always true that there's one |
| // there. We look at the beginning of the string for a run of upper-case letters. |
| // If there are more than 5, it's an error. |
| // If there are 4 or 5 and the last is a T, it's a time zone. |
| // If there are 3, it's a time zone. |
| // Otherwise, other than special cases, it's not a time zone. |
| // GMT is special because it can have an hour offset. |
| func parseTimeZone(value string) (length int, ok bool) { |
| if len(value) < 3 { |
| return 0, false |
| } |
| // Special case 1: ChST and MeST are the only zones with a lower-case letter. |
| if len(value) >= 4 && (value[:4] == "ChST" || value[:4] == "MeST") { |
| return 4, true |
| } |
| // Special case 2: GMT may have an hour offset; treat it specially. |
| if value[:3] == "GMT" { |
| length = parseGMT(value) |
| return length, true |
| } |
| // Special Case 3: Some time zones are not named, but have +/-00 format |
| if value[0] == '+' || value[0] == '-' { |
| length = parseSignedOffset(value) |
| ok := length > 0 // parseSignedOffset returns 0 in case of bad input |
| return length, ok |
| } |
| // How many upper-case letters are there? Need at least three, at most five. |
| var nUpper int |
| for nUpper = 0; nUpper < 6; nUpper++ { |
| if nUpper >= len(value) { |
| break |
| } |
| if c := value[nUpper]; c < 'A' || 'Z' < c { |
| break |
| } |
| } |
| switch nUpper { |
| case 0, 1, 2, 6: |
| return 0, false |
| case 5: // Must end in T to match. |
| if value[4] == 'T' { |
| return 5, true |
| } |
| case 4: |
| // Must end in T, except one special case. |
| if value[3] == 'T' || value[:4] == "WITA" { |
| return 4, true |
| } |
| case 3: |
| return 3, true |
| } |
| return 0, false |
| } |
| |
| // parseGMT parses a GMT time zone. The input string is known to start "GMT". |
| // The function checks whether that is followed by a sign and a number in the |
| // range -23 through +23 excluding zero. |
| func parseGMT(value string) int { |
| value = value[3:] |
| if len(value) == 0 { |
| return 3 |
| } |
| |
| return 3 + parseSignedOffset(value) |
| } |
| |
| // parseSignedOffset parses a signed timezone offset (e.g. "+03" or "-04"). |
| // The function checks for a signed number in the range -23 through +23 excluding zero. |
| // Returns length of the found offset string or 0 otherwise |
| func parseSignedOffset(value string) int { |
| sign := value[0] |
| if sign != '-' && sign != '+' { |
| return 0 |
| } |
| x, rem, err := leadingInt(value[1:]) |
| |
| // fail if nothing consumed by leadingInt |
| if err != nil || value[1:] == rem { |
| return 0 |
| } |
| if sign == '-' { |
| x = -x |
| } |
| if x < -23 || 23 < x { |
| return 0 |
| } |
| return len(value) - len(rem) |
| } |
| |
| func commaOrPeriod(b byte) bool { |
| return b == '.' || b == ',' |
| } |
| |
| func parseNanoseconds(value string, nbytes int) (ns int, rangeErrString string, err error) { |
| if !commaOrPeriod(value[0]) { |
| err = errBad |
| return |
| } |
| if ns, err = atoi(value[1:nbytes]); err != nil { |
| return |
| } |
| if ns < 0 || 1e9 <= ns { |
| rangeErrString = "fractional second" |
| return |
| } |
| // 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 - nbytes |
| for i := 0; i < scaleDigits; i++ { |
| ns *= 10 |
| } |
| return |
| } |
| |
| var errLeadingInt = errors.New("time: bad [0-9]*") // never printed |
| |
| // leadingInt consumes the leading [0-9]* from s. |
| func leadingInt(s string) (x int64, rem string, err error) { |
| i := 0 |
| for ; i < len(s); i++ { |
| c := s[i] |
| if c < '0' || c > '9' { |
| break |
| } |
| if x > (1<<63-1)/10 { |
| // overflow |
| return 0, "", errLeadingInt |
| } |
| x = x*10 + int64(c) - '0' |
| if x < 0 { |
| // overflow |
| return 0, "", errLeadingInt |
| } |
| } |
| return x, s[i:], nil |
| } |
| |
| // leadingFraction consumes the leading [0-9]* from s. |
| // It is used only for fractions, so does not return an error on overflow, |
| // it just stops accumulating precision. |
| func leadingFraction(s string) (x int64, scale float64, rem string) { |
| i := 0 |
| scale = 1 |
| overflow := false |
| for ; i < len(s); i++ { |
| c := s[i] |
| if c < '0' || c > '9' { |
| break |
| } |
| if overflow { |
| continue |
| } |
| if x > (1<<63-1)/10 { |
| // It's possible for overflow to give a positive number, so take care. |
| overflow = true |
| continue |
| } |
| y := x*10 + int64(c) - '0' |
| if y < 0 { |
| overflow = true |
| continue |
| } |
| x = y |
| scale *= 10 |
| } |
| return x, scale, s[i:] |
| } |
| |
| var unitMap = map[string]int64{ |
| "ns": int64(Nanosecond), |
| "us": int64(Microsecond), |
| "µs": int64(Microsecond), // U+00B5 = micro symbol |
| "μs": int64(Microsecond), // U+03BC = Greek letter mu |
| "ms": int64(Millisecond), |
| "s": int64(Second), |
| "m": int64(Minute), |
| "h": int64(Hour), |
| } |
| |
| // ParseDuration parses a duration string. |
| // A duration string is a possibly signed sequence of |
| // decimal numbers, each with optional fraction and a unit suffix, |
| // such as "300ms", "-1.5h" or "2h45m". |
| // Valid time units are "ns", "us" (or "µs"), "ms", "s", "m", "h". |
| func ParseDuration(s string) (Duration, error) { |
| // [-+]?([0-9]*(\.[0-9]*)?[a-z]+)+ |
| orig := s |
| var d int64 |
| neg := false |
| |
| // Consume [-+]? |
| if s != "" { |
| c := s[0] |
| if c == '-' || c == '+' { |
| neg = c == '-' |
| s = s[1:] |
| } |
| } |
| // Special case: if all that is left is "0", this is zero. |
| if s == "0" { |
| return 0, nil |
| } |
| if s == "" { |
| return 0, errors.New("time: invalid duration " + quote(orig)) |
| } |
| for s != "" { |
| var ( |
| v, f int64 // integers before, after decimal point |
| scale float64 = 1 // value = v + f/scale |
| ) |
| |
| var err error |
| |
| // The next character must be [0-9.] |
| if !(s[0] == '.' || '0' <= s[0] && s[0] <= '9') { |
| return 0, errors.New("time: invalid duration " + quote(orig)) |
| } |
| // Consume [0-9]* |
| pl := len(s) |
| v, s, err = leadingInt(s) |
| if err != nil { |
| return 0, errors.New("time: invalid duration " + quote(orig)) |
| } |
| pre := pl != len(s) // whether we consumed anything before a period |
| |
| // Consume (\.[0-9]*)? |
| post := false |
| if s != "" && s[0] == '.' { |
| s = s[1:] |
| pl := len(s) |
| f, scale, s = leadingFraction(s) |
| post = pl != len(s) |
| } |
| if !pre && !post { |
| // no digits (e.g. ".s" or "-.s") |
| return 0, errors.New("time: invalid duration " + quote(orig)) |
| } |
| |
| // Consume unit. |
| i := 0 |
| for ; i < len(s); i++ { |
| c := s[i] |
| if c == '.' || '0' <= c && c <= '9' { |
| break |
| } |
| } |
| if i == 0 { |
| return 0, errors.New("time: missing unit in duration " + quote(orig)) |
| } |
| u := s[:i] |
| s = s[i:] |
| unit, ok := unitMap[u] |
| if !ok { |
| return 0, errors.New("time: unknown unit " + quote(u) + " in duration " + quote(orig)) |
| } |
| if v > (1<<63-1)/unit { |
| // overflow |
| return 0, errors.New("time: invalid duration " + quote(orig)) |
| } |
| v *= unit |
| if f > 0 { |
| // float64 is needed to be nanosecond accurate for fractions of hours. |
| // v >= 0 && (f*unit/scale) <= 3.6e+12 (ns/h, h is the largest unit) |
| v += int64(float64(f) * (float64(unit) / scale)) |
| if v < 0 { |
| // overflow |
| return 0, errors.New("time: invalid duration " + quote(orig)) |
| } |
| } |
| d += v |
| if d < 0 { |
| // overflow |
| return 0, errors.New("time: invalid duration " + quote(orig)) |
| } |
| } |
| |
| if neg { |
| d = -d |
| } |
| return Duration(d), nil |
| } |