1 // Copyright 2010 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 package time 6 7 import "errors" 8 9 // These are predefined layouts for use in Time.Format and time.Parse. 10 // The reference time used in the layouts is the specific time: 11 // Mon Jan 2 15:04:05 MST 2006 12 // which is Unix time 1136239445. Since MST is GMT-0700, 13 // the reference time can be thought of as 14 // 01/02 03:04:05PM '06 -0700 15 // To define your own format, write down what the reference time would look 16 // like formatted your way; see the values of constants like ANSIC, 17 // StampMicro or Kitchen for examples. The model is to demonstrate what the 18 // reference time looks like so that the Format and Parse methods can apply 19 // the same transformation to a general time value. 20 // 21 // Some valid layouts are invalid time values for time.Parse, due to formats 22 // such as _ for space padding and Z for zone information. 23 // 24 // Within the format string, an underscore _ represents a space that may be 25 // replaced by a digit if the following number (a day) has two digits; for 26 // compatibility with fixed-width Unix time formats. 27 // 28 // A decimal point followed by one or more zeros represents a fractional 29 // second, printed to the given number of decimal places. A decimal point 30 // followed by one or more nines represents a fractional second, printed to 31 // the given number of decimal places, with trailing zeros removed. 32 // When parsing (only), the input may contain a fractional second 33 // field immediately after the seconds field, even if the layout does not 34 // signify its presence. In that case a decimal point followed by a maximal 35 // series of digits is parsed as a fractional second. 36 // 37 // Numeric time zone offsets format as follows: 38 // -0700 ±hhmm 39 // -07:00 ±hh:mm 40 // -07 ±hh 41 // Replacing the sign in the format with a Z triggers 42 // the ISO 8601 behavior of printing Z instead of an 43 // offset for the UTC zone. Thus: 44 // Z0700 Z or ±hhmm 45 // Z07:00 Z or ±hh:mm 46 // Z07 Z or ±hh 47 // 48 // The recognized day of week formats are "Mon" and "Monday". 49 // The recognized month formats are "Jan" and "January". 50 // 51 // The formats 2, _2, and 02 are unpadded, space-padded, and zero-padded 52 // day of month. The formats __2 and 002 are space-padded and zero-padded 53 // three-character day of year; there is no unpadded day of year format. 54 // 55 // Text in the format string that is not recognized as part of the reference 56 // time is echoed verbatim during Format and expected to appear verbatim 57 // in the input to Parse. 58 // 59 // The executable example for Time.Format demonstrates the working 60 // of the layout string in detail and is a good reference. 61 // 62 // Note that the RFC822, RFC850, and RFC1123 formats should be applied 63 // only to local times. Applying them to UTC times will use "UTC" as the 64 // time zone abbreviation, while strictly speaking those RFCs require the 65 // use of "GMT" in that case. 66 // In general RFC1123Z should be used instead of RFC1123 for servers 67 // that insist on that format, and RFC3339 should be preferred for new protocols. 68 // RFC3339, RFC822, RFC822Z, RFC1123, and RFC1123Z are useful for formatting; 69 // when used with time.Parse they do not accept all the time formats 70 // permitted by the RFCs. 71 // The RFC3339Nano format removes trailing zeros from the seconds field 72 // and thus may not sort correctly once formatted. 73 const ( 74 ANSIC = "Mon Jan _2 15:04:05 2006" 75 UnixDate = "Mon Jan _2 15:04:05 MST 2006" 76 RubyDate = "Mon Jan 02 15:04:05 -0700 2006" 77 RFC822 = "02 Jan 06 15:04 MST" 78 RFC822Z = "02 Jan 06 15:04 -0700" // RFC822 with numeric zone 79 RFC850 = "Monday, 02-Jan-06 15:04:05 MST" 80 RFC1123 = "Mon, 02 Jan 2006 15:04:05 MST" 81 RFC1123Z = "Mon, 02 Jan 2006 15:04:05 -0700" // RFC1123 with numeric zone 82 RFC3339 = "2006-01-02T15:04:05Z07:00" 83 RFC3339Nano = "2006-01-02T15:04:05.999999999Z07:00" 84 Kitchen = "3:04PM" 85 // Handy time stamps. 86 Stamp = "Jan _2 15:04:05" 87 StampMilli = "Jan _2 15:04:05.000" 88 StampMicro = "Jan _2 15:04:05.000000" 89 StampNano = "Jan _2 15:04:05.000000000" 90 ) 91 92 const ( 93 _ = iota 94 stdLongMonth = iota + stdNeedDate // "January" 95 stdMonth // "Jan" 96 stdNumMonth // "1" 97 stdZeroMonth // "01" 98 stdLongWeekDay // "Monday" 99 stdWeekDay // "Mon" 100 stdDay // "2" 101 stdUnderDay // "_2" 102 stdZeroDay // "02" 103 stdUnderYearDay // "__2" 104 stdZeroYearDay // "002" 105 stdHour = iota + stdNeedClock // "15" 106 stdHour12 // "3" 107 stdZeroHour12 // "03" 108 stdMinute // "4" 109 stdZeroMinute // "04" 110 stdSecond // "5" 111 stdZeroSecond // "05" 112 stdLongYear = iota + stdNeedDate // "2006" 113 stdYear // "06" 114 stdPM = iota + stdNeedClock // "PM" 115 stdpm // "pm" 116 stdTZ = iota // "MST" 117 stdISO8601TZ // "Z0700" // prints Z for UTC 118 stdISO8601SecondsTZ // "Z070000" 119 stdISO8601ShortTZ // "Z07" 120 stdISO8601ColonTZ // "Z07:00" // prints Z for UTC 121 stdISO8601ColonSecondsTZ // "Z07:00:00" 122 stdNumTZ // "-0700" // always numeric 123 stdNumSecondsTz // "-070000" 124 stdNumShortTZ // "-07" // always numeric 125 stdNumColonTZ // "-07:00" // always numeric 126 stdNumColonSecondsTZ // "-07:00:00" 127 stdFracSecond0 // ".0", ".00", ... , trailing zeros included 128 stdFracSecond9 // ".9", ".99", ..., trailing zeros omitted 129 130 stdNeedDate = 1 << 8 // need month, day, year 131 stdNeedClock = 2 << 8 // need hour, minute, second 132 stdArgShift = 16 // extra argument in high bits, above low stdArgShift 133 stdMask = 1<<stdArgShift - 1 // mask out argument 134 ) 135 136 // std0x records the std values for "01", "02", ..., "06". 137 var std0x = [...]int{stdZeroMonth, stdZeroDay, stdZeroHour12, stdZeroMinute, stdZeroSecond, stdYear} 138 139 // startsWithLowerCase reports whether the string has a lower-case letter at the beginning. 140 // Its purpose is to prevent matching strings like "Month" when looking for "Mon". 141 func startsWithLowerCase(str string) bool { 142 if len(str) == 0 { 143 return false 144 } 145 c := str[0] 146 return 'a' <= c && c <= 'z' 147 } 148 149 // nextStdChunk finds the first occurrence of a std string in 150 // layout and returns the text before, the std string, and the text after. 151 func nextStdChunk(layout string) (prefix string, std int, suffix string) { 152 for i := 0; i < len(layout); i++ { 153 switch c := int(layout[i]); c { 154 case 'J': // January, Jan 155 if len(layout) >= i+3 && layout[i:i+3] == "Jan" { 156 if len(layout) >= i+7 && layout[i:i+7] == "January" { 157 return layout[0:i], stdLongMonth, layout[i+7:] 158 } 159 if !startsWithLowerCase(layout[i+3:]) { 160 return layout[0:i], stdMonth, layout[i+3:] 161 } 162 } 163 164 case 'M': // Monday, Mon, MST 165 if len(layout) >= i+3 { 166 if layout[i:i+3] == "Mon" { 167 if len(layout) >= i+6 && layout[i:i+6] == "Monday" { 168 return layout[0:i], stdLongWeekDay, layout[i+6:] 169 } 170 if !startsWithLowerCase(layout[i+3:]) { 171 return layout[0:i], stdWeekDay, layout[i+3:] 172 } 173 } 174 if layout[i:i+3] == "MST" { 175 return layout[0:i], stdTZ, layout[i+3:] 176 } 177 } 178 179 case '0': // 01, 02, 03, 04, 05, 06, 002 180 if len(layout) >= i+2 && '1' <= layout[i+1] && layout[i+1] <= '6' { 181 return layout[0:i], std0x[layout[i+1]-'1'], layout[i+2:] 182 } 183 if len(layout) >= i+3 && layout[i+1] == '0' && layout[i+2] == '2' { 184 return layout[0:i], stdZeroYearDay, layout[i+3:] 185 } 186 187 case '1': // 15, 1 188 if len(layout) >= i+2 && layout[i+1] == '5' { 189 return layout[0:i], stdHour, layout[i+2:] 190 } 191 return layout[0:i], stdNumMonth, layout[i+1:] 192 193 case '2': // 2006, 2 194 if len(layout) >= i+4 && layout[i:i+4] == "2006" { 195 return layout[0:i], stdLongYear, layout[i+4:] 196 } 197 return layout[0:i], stdDay, layout[i+1:] 198 199 case '_': // _2, _2006, __2 200 if len(layout) >= i+2 && layout[i+1] == '2' { 201 //_2006 is really a literal _, followed by stdLongYear 202 if len(layout) >= i+5 && layout[i+1:i+5] == "2006" { 203 return layout[0 : i+1], stdLongYear, layout[i+5:] 204 } 205 return layout[0:i], stdUnderDay, layout[i+2:] 206 } 207 if len(layout) >= i+3 && layout[i+1] == '_' && layout[i+2] == '2' { 208 return layout[0:i], stdUnderYearDay, layout[i+3:] 209 } 210 211 case '3': 212 return layout[0:i], stdHour12, layout[i+1:] 213 214 case '4': 215 return layout[0:i], stdMinute, layout[i+1:] 216 217 case '5': 218 return layout[0:i], stdSecond, layout[i+1:] 219 220 case 'P': // PM 221 if len(layout) >= i+2 && layout[i+1] == 'M' { 222 return layout[0:i], stdPM, layout[i+2:] 223 } 224 225 case 'p': // pm 226 if len(layout) >= i+2 && layout[i+1] == 'm' { 227 return layout[0:i], stdpm, layout[i+2:] 228 } 229 230 case '-': // -070000, -07:00:00, -0700, -07:00, -07 231 if len(layout) >= i+7 && layout[i:i+7] == "-070000" { 232 return layout[0:i], stdNumSecondsTz, layout[i+7:] 233 } 234 if len(layout) >= i+9 && layout[i:i+9] == "-07:00:00" { 235 return layout[0:i], stdNumColonSecondsTZ, layout[i+9:] 236 } 237 if len(layout) >= i+5 && layout[i:i+5] == "-0700" { 238 return layout[0:i], stdNumTZ, layout[i+5:] 239 } 240 if len(layout) >= i+6 && layout[i:i+6] == "-07:00" { 241 return layout[0:i], stdNumColonTZ, layout[i+6:] 242 } 243 if len(layout) >= i+3 && layout[i:i+3] == "-07" { 244 return layout[0:i], stdNumShortTZ, layout[i+3:] 245 } 246 247 case 'Z': // Z070000, Z07:00:00, Z0700, Z07:00, 248 if len(layout) >= i+7 && layout[i:i+7] == "Z070000" { 249 return layout[0:i], stdISO8601SecondsTZ, layout[i+7:] 250 } 251 if len(layout) >= i+9 && layout[i:i+9] == "Z07:00:00" { 252 return layout[0:i], stdISO8601ColonSecondsTZ, layout[i+9:] 253 } 254 if len(layout) >= i+5 && layout[i:i+5] == "Z0700" { 255 return layout[0:i], stdISO8601TZ, layout[i+5:] 256 } 257 if len(layout) >= i+6 && layout[i:i+6] == "Z07:00" { 258 return layout[0:i], stdISO8601ColonTZ, layout[i+6:] 259 } 260 if len(layout) >= i+3 && layout[i:i+3] == "Z07" { 261 return layout[0:i], stdISO8601ShortTZ, layout[i+3:] 262 } 263 264 case '.': // .000 or .999 - repeated digits for fractional seconds. 265 if i+1 < len(layout) && (layout[i+1] == '0' || layout[i+1] == '9') { 266 ch := layout[i+1] 267 j := i + 1 268 for j < len(layout) && layout[j] == ch { 269 j++ 270 } 271 // String of digits must end here - only fractional second is all digits. 272 if !isDigit(layout, j) { 273 std := stdFracSecond0 274 if layout[i+1] == '9' { 275 std = stdFracSecond9 276 } 277 std |= (j - (i + 1)) << stdArgShift 278 return layout[0:i], std, layout[j:] 279 } 280 } 281 } 282 } 283 return layout, 0, "" 284 } 285 286 var longDayNames = []string{ 287 "Sunday", 288 "Monday", 289 "Tuesday", 290 "Wednesday", 291 "Thursday", 292 "Friday", 293 "Saturday", 294 } 295 296 var shortDayNames = []string{ 297 "Sun", 298 "Mon", 299 "Tue", 300 "Wed", 301 "Thu", 302 "Fri", 303 "Sat", 304 } 305 306 var shortMonthNames = []string{ 307 "Jan", 308 "Feb", 309 "Mar", 310 "Apr", 311 "May", 312 "Jun", 313 "Jul", 314 "Aug", 315 "Sep", 316 "Oct", 317 "Nov", 318 "Dec", 319 } 320 321 var longMonthNames = []string{ 322 "January", 323 "February", 324 "March", 325 "April", 326 "May", 327 "June", 328 "July", 329 "August", 330 "September", 331 "October", 332 "November", 333 "December", 334 } 335 336 // match reports whether s1 and s2 match ignoring case. 337 // It is assumed s1 and s2 are the same length. 338 func match(s1, s2 string) bool { 339 for i := 0; i < len(s1); i++ { 340 c1 := s1[i] 341 c2 := s2[i] 342 if c1 != c2 { 343 // Switch to lower-case; 'a'-'A' is known to be a single bit. 344 c1 |= 'a' - 'A' 345 c2 |= 'a' - 'A' 346 if c1 != c2 || c1 < 'a' || c1 > 'z' { 347 return false 348 } 349 } 350 } 351 return true 352 } 353 354 func lookup(tab []string, val string) (int, string, error) { 355 for i, v := range tab { 356 if len(val) >= len(v) && match(val[0:len(v)], v) { 357 return i, val[len(v):], nil 358 } 359 } 360 return -1, val, errBad 361 } 362 363 // appendInt appends the decimal form of x to b and returns the result. 364 // If the decimal form (excluding sign) is shorter than width, the result is padded with leading 0's. 365 // Duplicates functionality in strconv, but avoids dependency. 366 func appendInt(b []byte, x int, width int) []byte { 367 u := uint(x) 368 if x < 0 { 369 b = append(b, '-') 370 u = uint(-x) 371 } 372 373 // Assemble decimal in reverse order. 374 var buf [20]byte 375 i := len(buf) 376 for u >= 10 { 377 i-- 378 q := u / 10 379 buf[i] = byte('0' + u - q*10) 380 u = q 381 } 382 i-- 383 buf[i] = byte('0' + u) 384 385 // Add 0-padding. 386 for w := len(buf) - i; w < width; w++ { 387 b = append(b, '0') 388 } 389 390 return append(b, buf[i:]...) 391 } 392 393 // Never printed, just needs to be non-nil for return by atoi. 394 var atoiError = errors.New("time: invalid number") 395 396 // Duplicates functionality in strconv, but avoids dependency. 397 func atoi(s string) (x int, err error) { 398 neg := false 399 if s != "" && (s[0] == '-' || s[0] == '+') { 400 neg = s[0] == '-' 401 s = s[1:] 402 } 403 q, rem, err := leadingInt(s) 404 x = int(q) 405 if err != nil || rem != "" { 406 return 0, atoiError 407 } 408 if neg { 409 x = -x 410 } 411 return x, nil 412 } 413 414 // formatNano appends a fractional second, as nanoseconds, to b 415 // and returns the result. 416 func formatNano(b []byte, nanosec uint, n int, trim bool) []byte { 417 u := nanosec 418 var buf [9]byte 419 for start := len(buf); start > 0; { 420 start-- 421 buf[start] = byte(u%10 + '0') 422 u /= 10 423 } 424 425 if n > 9 { 426 n = 9 427 } 428 if trim { 429 for n > 0 && buf[n-1] == '0' { 430 n-- 431 } 432 if n == 0 { 433 return b 434 } 435 } 436 b = append(b, '.') 437 return append(b, buf[:n]...) 438 } 439 440 // String returns the time formatted using the format string 441 // "2006-01-02 15:04:05.999999999 -0700 MST" 442 // 443 // If the time has a monotonic clock reading, the returned string 444 // includes a final field "m=±<value>", where value is the monotonic 445 // clock reading formatted as a decimal number of seconds. 446 // 447 // The returned string is meant for debugging; for a stable serialized 448 // representation, use t.MarshalText, t.MarshalBinary, or t.Format 449 // with an explicit format string. 450 func (t Time) String() string { 451 s := t.Format("2006-01-02 15:04:05.999999999 -0700 MST") 452 453 // Format monotonic clock reading as m=±ddd.nnnnnnnnn. 454 if t.wall&hasMonotonic != 0 { 455 m2 := uint64(t.ext) 456 sign := byte('+') 457 if t.ext < 0 { 458 sign = '-' 459 m2 = -m2 460 } 461 m1, m2 := m2/1e9, m2%1e9 462 m0, m1 := m1/1e9, m1%1e9 463 var buf []byte 464 buf = append(buf, " m="...) 465 buf = append(buf, sign) 466 wid := 0 467 if m0 != 0 { 468 buf = appendInt(buf, int(m0), 0) 469 wid = 9 470 } 471 buf = appendInt(buf, int(m1), wid) 472 buf = append(buf, '.') 473 buf = appendInt(buf, int(m2), 9) 474 s += string(buf) 475 } 476 return s 477 } 478 479 // Format returns a textual representation of the time value formatted 480 // according to layout, which defines the format by showing how the reference 481 // time, defined to be 482 // Mon Jan 2 15:04:05 -0700 MST 2006 483 // would be displayed if it were the value; it serves as an example of the 484 // desired output. The same display rules will then be applied to the time 485 // value. 486 // 487 // A fractional second is represented by adding a period and zeros 488 // to the end of the seconds section of layout string, as in "15:04:05.000" 489 // to format a time stamp with millisecond precision. 490 // 491 // Predefined layouts ANSIC, UnixDate, RFC3339 and others describe standard 492 // and convenient representations of the reference time. For more information 493 // about the formats and the definition of the reference time, see the 494 // documentation for ANSIC and the other constants defined by this package. 495 func (t Time) Format(layout string) string { 496 const bufSize = 64 497 var b []byte 498 max := len(layout) + 10 499 if max < bufSize { 500 var buf [bufSize]byte 501 b = buf[:0] 502 } else { 503 b = make([]byte, 0, max) 504 } 505 b = t.AppendFormat(b, layout) 506 return string(b) 507 } 508 509 // AppendFormat is like Format but appends the textual 510 // representation to b and returns the extended buffer. 511 func (t Time) AppendFormat(b []byte, layout string) []byte { 512 var ( 513 name, offset, abs = t.locabs() 514 515 year int = -1 516 month Month 517 day int 518 yday int 519 hour int = -1 520 min int 521 sec int 522 ) 523 // Each iteration generates one std value. 524 for layout != "" { 525 prefix, std, suffix := nextStdChunk(layout) 526 if prefix != "" { 527 b = append(b, prefix...) 528 } 529 if std == 0 { 530 break 531 } 532 layout = suffix 533 534 // Compute year, month, day if needed. 535 if year < 0 && std&stdNeedDate != 0 { 536 year, month, day, yday = absDate(abs, true) 537 yday++ 538 } 539 540 // Compute hour, minute, second if needed. 541 if hour < 0 && std&stdNeedClock != 0 { 542 hour, min, sec = absClock(abs) 543 } 544 545 switch std & stdMask { 546 case stdYear: 547 y := year 548 if y < 0 { 549 y = -y 550 } 551 b = appendInt(b, y%100, 2) 552 case stdLongYear: 553 b = appendInt(b, year, 4) 554 case stdMonth: 555 b = append(b, month.String()[:3]...) 556 case stdLongMonth: 557 m := month.String() 558 b = append(b, m...) 559 case stdNumMonth: 560 b = appendInt(b, int(month), 0) 561 case stdZeroMonth: 562 b = appendInt(b, int(month), 2) 563 case stdWeekDay: 564 b = append(b, absWeekday(abs).String()[:3]...) 565 case stdLongWeekDay: 566 s := absWeekday(abs).String() 567 b = append(b, s...) 568 case stdDay: 569 b = appendInt(b, day, 0) 570 case stdUnderDay: 571 if day < 10 { 572 b = append(b, ' ') 573 } 574 b = appendInt(b, day, 0) 575 case stdZeroDay: 576 b = appendInt(b, day, 2) 577 case stdUnderYearDay: 578 if yday < 100 { 579 b = append(b, ' ') 580 if yday < 10 { 581 b = append(b, ' ') 582 } 583 } 584 b = appendInt(b, yday, 0) 585 case stdZeroYearDay: 586 b = appendInt(b, yday, 3) 587 case stdHour: 588 b = appendInt(b, hour, 2) 589 case stdHour12: 590 // Noon is 12PM, midnight is 12AM. 591 hr := hour % 12 592 if hr == 0 { 593 hr = 12 594 } 595 b = appendInt(b, hr, 0) 596 case stdZeroHour12: 597 // Noon is 12PM, midnight is 12AM. 598 hr := hour % 12 599 if hr == 0 { 600 hr = 12 601 } 602 b = appendInt(b, hr, 2) 603 case stdMinute: 604 b = appendInt(b, min, 0) 605 case stdZeroMinute: 606 b = appendInt(b, min, 2) 607 case stdSecond: 608 b = appendInt(b, sec, 0) 609 case stdZeroSecond: 610 b = appendInt(b, sec, 2) 611 case stdPM: 612 if hour >= 12 { 613 b = append(b, "PM"...) 614 } else { 615 b = append(b, "AM"...) 616 } 617 case stdpm: 618 if hour >= 12 { 619 b = append(b, "pm"...) 620 } else { 621 b = append(b, "am"...) 622 } 623 case stdISO8601TZ, stdISO8601ColonTZ, stdISO8601SecondsTZ, stdISO8601ShortTZ, stdISO8601ColonSecondsTZ, stdNumTZ, stdNumColonTZ, stdNumSecondsTz, stdNumShortTZ, stdNumColonSecondsTZ: 624 // Ugly special case. We cheat and take the "Z" variants 625 // to mean "the time zone as formatted for ISO 8601". 626 if offset == 0 && (std == stdISO8601TZ || std == stdISO8601ColonTZ || std == stdISO8601SecondsTZ || std == stdISO8601ShortTZ || std == stdISO8601ColonSecondsTZ) { 627 b = append(b, 'Z') 628 break 629 } 630 zone := offset / 60 // convert to minutes 631 absoffset := offset 632 if zone < 0 { 633 b = append(b, '-') 634 zone = -zone 635 absoffset = -absoffset 636 } else { 637 b = append(b, '+') 638 } 639 b = appendInt(b, zone/60, 2) 640 if std == stdISO8601ColonTZ || std == stdNumColonTZ || std == stdISO8601ColonSecondsTZ || std == stdNumColonSecondsTZ { 641 b = append(b, ':') 642 } 643 if std != stdNumShortTZ && std != stdISO8601ShortTZ { 644 b = appendInt(b, zone%60, 2) 645 } 646 647 // append seconds if appropriate 648 if std == stdISO8601SecondsTZ || std == stdNumSecondsTz || std == stdNumColonSecondsTZ || std == stdISO8601ColonSecondsTZ { 649 if std == stdNumColonSecondsTZ || std == stdISO8601ColonSecondsTZ { 650 b = append(b, ':') 651 } 652 b = appendInt(b, absoffset%60, 2) 653 } 654 655 case stdTZ: 656 if name != "" { 657 b = append(b, name...) 658 break 659 } 660 // No time zone known for this time, but we must print one. 661 // Use the -0700 format. 662 zone := offset / 60 // convert to minutes 663 if zone < 0 { 664 b = append(b, '-') 665 zone = -zone 666 } else { 667 b = append(b, '+') 668 } 669 b = appendInt(b, zone/60, 2) 670 b = appendInt(b, zone%60, 2) 671 case stdFracSecond0, stdFracSecond9: 672 b = formatNano(b, uint(t.Nanosecond()), std>>stdArgShift, std&stdMask == stdFracSecond9) 673 } 674 } 675 return b 676 } 677 678 var errBad = errors.New("bad value for field") // placeholder not passed to user 679 680 // ParseError describes a problem parsing a time string. 681 type ParseError struct { 682 Layout string 683 Value string 684 LayoutElem string 685 ValueElem string 686 Message string 687 } 688 689 func quote(s string) string { 690 return "\"" + s + "\"" 691 } 692 693 // Error returns the string representation of a ParseError. 694 func (e *ParseError) Error() string { 695 if e.Message == "" { 696 return "parsing time " + 697 quote(e.Value) + " as " + 698 quote(e.Layout) + ": cannot parse " + 699 quote(e.ValueElem) + " as " + 700 quote(e.LayoutElem) 701 } 702 return "parsing time " + 703 quote(e.Value) + e.Message 704 } 705 706 // isDigit reports whether s[i] is in range and is a decimal digit. 707 func isDigit(s string, i int) bool { 708 if len(s) <= i { 709 return false 710 } 711 c := s[i] 712 return '0' <= c && c <= '9' 713 } 714 715 // getnum parses s[0:1] or s[0:2] (fixed forces s[0:2]) 716 // as a decimal integer and returns the integer and the 717 // remainder of the string. 718 func getnum(s string, fixed bool) (int, string, error) { 719 if !isDigit(s, 0) { 720 return 0, s, errBad 721 } 722 if !isDigit(s, 1) { 723 if fixed { 724 return 0, s, errBad 725 } 726 return int(s[0] - '0'), s[1:], nil 727 } 728 return int(s[0]-'0')*10 + int(s[1]-'0'), s[2:], nil 729 } 730 731 // getnum3 parses s[0:1], s[0:2], or s[0:3] (fixed forces s[0:3]) 732 // as a decimal integer and returns the integer and the remainder 733 // of the string. 734 func getnum3(s string, fixed bool) (int, string, error) { 735 var n, i int 736 for i = 0; i < 3 && isDigit(s, i); i++ { 737 n = n*10 + int(s[i]-'0') 738 } 739 if i == 0 || fixed && i != 3 { 740 return 0, s, errBad 741 } 742 return n, s[i:], nil 743 } 744 745 func cutspace(s string) string { 746 for len(s) > 0 && s[0] == ' ' { 747 s = s[1:] 748 } 749 return s 750 } 751 752 // skip removes the given prefix from value, 753 // treating runs of space characters as equivalent. 754 func skip(value, prefix string) (string, error) { 755 for len(prefix) > 0 { 756 if prefix[0] == ' ' { 757 if len(value) > 0 && value[0] != ' ' { 758 return value, errBad 759 } 760 prefix = cutspace(prefix) 761 value = cutspace(value) 762 continue 763 } 764 if len(value) == 0 || value[0] != prefix[0] { 765 return value, errBad 766 } 767 prefix = prefix[1:] 768 value = value[1:] 769 } 770 return value, nil 771 } 772 773 // Parse parses a formatted string and returns the time value it represents. 774 // The layout defines the format by showing how the reference time, 775 // defined to be 776 // Mon Jan 2 15:04:05 -0700 MST 2006 777 // would be interpreted if it were the value; it serves as an example of 778 // the input format. The same interpretation will then be made to the 779 // input string. 780 // 781 // Predefined layouts ANSIC, UnixDate, RFC3339 and others describe standard 782 // and convenient representations of the reference time. For more information 783 // about the formats and the definition of the reference time, see the 784 // documentation for ANSIC and the other constants defined by this package. 785 // Also, the executable example for Time.Format demonstrates the working 786 // of the layout string in detail and is a good reference. 787 // 788 // Elements omitted from the value are assumed to be zero or, when 789 // zero is impossible, one, so parsing "3:04pm" returns the time 790 // corresponding to Jan 1, year 0, 15:04:00 UTC (note that because the year is 791 // 0, this time is before the zero Time). 792 // Years must be in the range 0000..9999. The day of the week is checked 793 // for syntax but it is otherwise ignored. 794 // 795 // In the absence of a time zone indicator, Parse returns a time in UTC. 796 // 797 // When parsing a time with a zone offset like -0700, if the offset corresponds 798 // to a time zone used by the current location (Local), then Parse uses that 799 // location and zone in the returned time. Otherwise it records the time as 800 // being in a fabricated location with time fixed at the given zone offset. 801 // 802 // When parsing a time with a zone abbreviation like MST, if the zone abbreviation 803 // has a defined offset in the current location, then that offset is used. 804 // The zone abbreviation "UTC" is recognized as UTC regardless of location. 805 // If the zone abbreviation is unknown, Parse records the time as being 806 // in a fabricated location with the given zone abbreviation and a zero offset. 807 // This choice means that such a time can be parsed and reformatted with the 808 // same layout losslessly, but the exact instant used in the representation will 809 // differ by the actual zone offset. To avoid such problems, prefer time layouts 810 // that use a numeric zone offset, or use ParseInLocation. 811 func Parse(layout, value string) (Time, error) { 812 return parse(layout, value, UTC, Local) 813 } 814 815 // ParseInLocation is like Parse but differs in two important ways. 816 // First, in the absence of time zone information, Parse interprets a time as UTC; 817 // ParseInLocation interprets the time as in the given location. 818 // Second, when given a zone offset or abbreviation, Parse tries to match it 819 // against the Local location; ParseInLocation uses the given location. 820 func ParseInLocation(layout, value string, loc *Location) (Time, error) { 821 return parse(layout, value, loc, loc) 822 } 823 824 func parse(layout, value string, defaultLocation, local *Location) (Time, error) { 825 alayout, avalue := layout, value 826 rangeErrString := "" // set if a value is out of range 827 amSet := false // do we need to subtract 12 from the hour for midnight? 828 pmSet := false // do we need to add 12 to the hour? 829 830 // Time being constructed. 831 var ( 832 year int 833 month int = -1 834 day int = -1 835 yday int = -1 836 hour int 837 min int 838 sec int 839 nsec int 840 z *Location 841 zoneOffset int = -1 842 zoneName string 843 ) 844 845 // Each iteration processes one std value. 846 for { 847 var err error 848 prefix, std, suffix := nextStdChunk(layout) 849 stdstr := layout[len(prefix) : len(layout)-len(suffix)] 850 value, err = skip(value, prefix) 851 if err != nil { 852 return Time{}, &ParseError{alayout, avalue, prefix, value, ""} 853 } 854 if std == 0 { 855 if len(value) != 0 { 856 return Time{}, &ParseError{alayout, avalue, "", value, ": extra text: " + value} 857 } 858 break 859 } 860 layout = suffix 861 var p string 862 switch std & stdMask { 863 case stdYear: 864 if len(value) < 2 { 865 err = errBad 866 break 867 } 868 hold := value 869 p, value = value[0:2], value[2:] 870 year, err = atoi(p) 871 if err != nil { 872 value = hold 873 } else if year >= 69 { // Unix time starts Dec 31 1969 in some time zones 874 year += 1900 875 } else { 876 year += 2000 877 } 878 case stdLongYear: 879 if len(value) < 4 || !isDigit(value, 0) { 880 err = errBad 881 break 882 } 883 p, value = value[0:4], value[4:] 884 year, err = atoi(p) 885 case stdMonth: 886 month, value, err = lookup(shortMonthNames, value) 887 month++ 888 case stdLongMonth: 889 month, value, err = lookup(longMonthNames, value) 890 month++ 891 case stdNumMonth, stdZeroMonth: 892 month, value, err = getnum(value, std == stdZeroMonth) 893 if err == nil && (month <= 0 || 12 < month) { 894 rangeErrString = "month" 895 } 896 case stdWeekDay: 897 // Ignore weekday except for error checking. 898 _, value, err = lookup(shortDayNames, value) 899 case stdLongWeekDay: 900 _, value, err = lookup(longDayNames, value) 901 case stdDay, stdUnderDay, stdZeroDay: 902 if std == stdUnderDay && len(value) > 0 && value[0] == ' ' { 903 value = value[1:] 904 } 905 day, value, err = getnum(value, std == stdZeroDay) 906 // Note that we allow any one- or two-digit day here. 907 // The month, day, year combination is validated after we've completed parsing. 908 case stdUnderYearDay, stdZeroYearDay: 909 for i := 0; i < 2; i++ { 910 if std == stdUnderYearDay && len(value) > 0 && value[0] == ' ' { 911 value = value[1:] 912 } 913 } 914 yday, value, err = getnum3(value, std == stdZeroYearDay) 915 // Note that we allow any one-, two-, or three-digit year-day here. 916 // The year-day, year combination is validated after we've completed parsing. 917 case stdHour: 918 hour, value, err = getnum(value, false) 919 if hour < 0 || 24 <= hour { 920 rangeErrString = "hour" 921 } 922 case stdHour12, stdZeroHour12: 923 hour, value, err = getnum(value, std == stdZeroHour12) 924 if hour < 0 || 12 < hour { 925 rangeErrString = "hour" 926 } 927 case stdMinute, stdZeroMinute: 928 min, value, err = getnum(value, std == stdZeroMinute) 929 if min < 0 || 60 <= min { 930 rangeErrString = "minute" 931 } 932 case stdSecond, stdZeroSecond: 933 sec, value, err = getnum(value, std == stdZeroSecond) 934 if sec < 0 || 60 <= sec { 935 rangeErrString = "second" 936 break 937 } 938 // Special case: do we have a fractional second but no 939 // fractional second in the format? 940 if len(value) >= 2 && value[0] == '.' && isDigit(value, 1) { 941 _, std, _ = nextStdChunk(layout) 942 std &= stdMask 943 if std == stdFracSecond0 || std == stdFracSecond9 { 944 // Fractional second in the layout; proceed normally 945 break 946 } 947 // No fractional second in the layout but we have one in the input. 948 n := 2 949 for ; n < len(value) && isDigit(value, n); n++ { 950 } 951 nsec, rangeErrString, err = parseNanoseconds(value, n) 952 value = value[n:] 953 } 954 case stdPM: 955 if len(value) < 2 { 956 err = errBad 957 break 958 } 959 p, value = value[0:2], value[2:] 960 switch p { 961 case "PM": 962 pmSet = true 963 case "AM": 964 amSet = true 965 default: 966 err = errBad 967 } 968 case stdpm: 969 if len(value) < 2 { 970 err = errBad 971 break 972 } 973 p, value = value[0:2], value[2:] 974 switch p { 975 case "pm": 976 pmSet = true 977 case "am": 978 amSet = true 979 default: 980 err = errBad 981 } 982 case stdISO8601TZ, stdISO8601ColonTZ, stdISO8601SecondsTZ, stdISO8601ShortTZ, stdISO8601ColonSecondsTZ, stdNumTZ, stdNumShortTZ, stdNumColonTZ, stdNumSecondsTz, stdNumColonSecondsTZ: 983 if (std == stdISO8601TZ || std == stdISO8601ShortTZ || std == stdISO8601ColonTZ) && len(value) >= 1 && value[0] == 'Z' { 984 value = value[1:] 985 z = UTC 986 break 987 } 988 var sign, hour, min, seconds string 989 if std == stdISO8601ColonTZ || std == stdNumColonTZ { 990 if len(value) < 6 { 991 err = errBad 992 break 993 } 994 if value[3] != ':' { 995 err = errBad 996 break 997 } 998 sign, hour, min, seconds, value = value[0:1], value[1:3], value[4:6], "00", value[6:] 999 } else if std == stdNumShortTZ || std == stdISO8601ShortTZ { 1000 if len(value) < 3 { 1001 err = errBad 1002 break 1003 } 1004 sign, hour, min, seconds, value = value[0:1], value[1:3], "00", "00", value[3:] 1005 } else if std == stdISO8601ColonSecondsTZ || std == stdNumColonSecondsTZ { 1006 if len(value) < 9 { 1007 err = errBad 1008 break 1009 } 1010 if value[3] != ':' || value[6] != ':' { 1011 err = errBad 1012 break 1013 } 1014 sign, hour, min, seconds, value = value[0:1], value[1:3], value[4:6], value[7:9], value[9:] 1015 } else if std == stdISO8601SecondsTZ || std == stdNumSecondsTz { 1016 if len(value) < 7 { 1017 err = errBad 1018 break 1019 } 1020 sign, hour, min, seconds, value = value[0:1], value[1:3], value[3:5], value[5:7], value[7:] 1021 } else { 1022 if len(value) < 5 { 1023 err = errBad 1024 break 1025 } 1026 sign, hour, min, seconds, value = value[0:1], value[1:3], value[3:5], "00", value[5:] 1027 } 1028 var hr, mm, ss int 1029 hr, err = atoi(hour) 1030 if err == nil { 1031 mm, err = atoi(min) 1032 } 1033 if err == nil { 1034 ss, err = atoi(seconds) 1035 } 1036 zoneOffset = (hr*60+mm)*60 + ss // offset is in seconds 1037 switch sign[0] { 1038 case '+': 1039 case '-': 1040 zoneOffset = -zoneOffset 1041 default: 1042 err = errBad 1043 } 1044 case stdTZ: 1045 // Does it look like a time zone? 1046 if len(value) >= 3 && value[0:3] == "UTC" { 1047 z = UTC 1048 value = value[3:] 1049 break 1050 } 1051 n, ok := parseTimeZone(value) 1052 if !ok { 1053 err = errBad 1054 break 1055 } 1056 zoneName, value = value[:n], value[n:] 1057 1058 case stdFracSecond0: 1059 // stdFracSecond0 requires the exact number of digits as specified in 1060 // the layout. 1061 ndigit := 1 + (std >> stdArgShift) 1062 if len(value) < ndigit { 1063 err = errBad 1064 break 1065 } 1066 nsec, rangeErrString, err = parseNanoseconds(value, ndigit) 1067 value = value[ndigit:] 1068 1069 case stdFracSecond9: 1070 if len(value) < 2 || value[0] != '.' || value[1] < '0' || '9' < value[1] { 1071 // Fractional second omitted. 1072 break 1073 } 1074 // Take any number of digits, even more than asked for, 1075 // because it is what the stdSecond case would do. 1076 i := 0 1077 for i < 9 && i+1 < len(value) && '0' <= value[i+1] && value[i+1] <= '9' { 1078 i++ 1079 } 1080 nsec, rangeErrString, err = parseNanoseconds(value, 1+i) 1081 value = value[1+i:] 1082 } 1083 if rangeErrString != "" { 1084 return Time{}, &ParseError{alayout, avalue, stdstr, value, ": " + rangeErrString + " out of range"} 1085 } 1086 if err != nil { 1087 return Time{}, &ParseError{alayout, avalue, stdstr, value, ""} 1088 } 1089 } 1090 if pmSet && hour < 12 { 1091 hour += 12 1092 } else if amSet && hour == 12 { 1093 hour = 0 1094 } 1095 1096 // Convert yday to day, month. 1097 if yday >= 0 { 1098 var d int 1099 var m int 1100 if isLeap(year) { 1101 if yday == 31+29 { 1102 m = int(February) 1103 d = 29 1104 } else if yday > 31+29 { 1105 yday-- 1106 } 1107 } 1108 if yday < 1 || yday > 365 { 1109 return Time{}, &ParseError{alayout, avalue, "", value, ": day-of-year out of range"} 1110 } 1111 if m == 0 { 1112 m = yday/31 + 1 1113 if int(daysBefore[m]) < yday { 1114 m++ 1115 } 1116 d = yday - int(daysBefore[m-1]) 1117 } 1118 // If month, day already seen, yday's m, d must match. 1119 // Otherwise, set them from m, d. 1120 if month >= 0 && month != m { 1121 return Time{}, &ParseError{alayout, avalue, "", value, ": day-of-year does not match month"} 1122 } 1123 month = m 1124 if day >= 0 && day != d { 1125 return Time{}, &ParseError{alayout, avalue, "", value, ": day-of-year does not match day"} 1126 } 1127 day = d 1128 } else { 1129 if month < 0 { 1130 month = int(January) 1131 } 1132 if day < 0 { 1133 day = 1 1134 } 1135 } 1136 1137 // Validate the day of the month. 1138 if day < 1 || day > daysIn(Month(month), year) { 1139 return Time{}, &ParseError{alayout, avalue, "", value, ": day out of range"} 1140 } 1141 1142 if z != nil { 1143 return Date(year, Month(month), day, hour, min, sec, nsec, z), nil 1144 } 1145 1146 if zoneOffset != -1 { 1147 t := Date(year, Month(month), day, hour, min, sec, nsec, UTC) 1148 t.addSec(-int64(zoneOffset)) 1149 1150 // Look for local zone with the given offset. 1151 // If that zone was in effect at the given time, use it. 1152 name, offset, _, _ := local.lookup(t.unixSec()) 1153 if offset == zoneOffset && (zoneName == "" || name == zoneName) { 1154 t.setLoc(local) 1155 return t, nil 1156 } 1157 1158 // Otherwise create fake zone to record offset. 1159 t.setLoc(FixedZone(zoneName, zoneOffset)) 1160 return t, nil 1161 } 1162 1163 if zoneName != "" { 1164 t := Date(year, Month(month), day, hour, min, sec, nsec, UTC) 1165 // Look for local zone with the given offset. 1166 // If that zone was in effect at the given time, use it. 1167 offset, ok := local.lookupName(zoneName, t.unixSec()) 1168 if ok { 1169 t.addSec(-int64(offset)) 1170 t.setLoc(local) 1171 return t, nil 1172 } 1173 1174 // Otherwise, create fake zone with unknown offset. 1175 if len(zoneName) > 3 && zoneName[:3] == "GMT" { 1176 offset, _ = atoi(zoneName[3:]) // Guaranteed OK by parseGMT. 1177 offset *= 3600 1178 } 1179 t.setLoc(FixedZone(zoneName, offset)) 1180 return t, nil 1181 } 1182 1183 // Otherwise, fall back to default. 1184 return Date(year, Month(month), day, hour, min, sec, nsec, defaultLocation), nil 1185 } 1186 1187 // parseTimeZone parses a time zone string and returns its length. Time zones 1188 // are human-generated and unpredictable. We can't do precise error checking. 1189 // On the other hand, for a correct parse there must be a time zone at the 1190 // beginning of the string, so it's almost always true that there's one 1191 // there. We look at the beginning of the string for a run of upper-case letters. 1192 // If there are more than 5, it's an error. 1193 // If there are 4 or 5 and the last is a T, it's a time zone. 1194 // If there are 3, it's a time zone. 1195 // Otherwise, other than special cases, it's not a time zone. 1196 // GMT is special because it can have an hour offset. 1197 func parseTimeZone(value string) (length int, ok bool) { 1198 if len(value) < 3 { 1199 return 0, false 1200 } 1201 // Special case 1: ChST and MeST are the only zones with a lower-case letter. 1202 if len(value) >= 4 && (value[:4] == "ChST" || value[:4] == "MeST") { 1203 return 4, true 1204 } 1205 // Special case 2: GMT may have an hour offset; treat it specially. 1206 if value[:3] == "GMT" { 1207 length = parseGMT(value) 1208 return length, true 1209 } 1210 // Special Case 3: Some time zones are not named, but have +/-00 format 1211 if value[0] == '+' || value[0] == '-' { 1212 length = parseSignedOffset(value) 1213 ok := length > 0 // parseSignedOffset returns 0 in case of bad input 1214 return length, ok 1215 } 1216 // How many upper-case letters are there? Need at least three, at most five. 1217 var nUpper int 1218 for nUpper = 0; nUpper < 6; nUpper++ { 1219 if nUpper >= len(value) { 1220 break 1221 } 1222 if c := value[nUpper]; c < 'A' || 'Z' < c { 1223 break 1224 } 1225 } 1226 switch nUpper { 1227 case 0, 1, 2, 6: 1228 return 0, false 1229 case 5: // Must end in T to match. 1230 if value[4] == 'T' { 1231 return 5, true 1232 } 1233 case 4: 1234 // Must end in T, except one special case. 1235 if value[3] == 'T' || value[:4] == "WITA" { 1236 return 4, true 1237 } 1238 case 3: 1239 return 3, true 1240 } 1241 return 0, false 1242 } 1243 1244 // parseGMT parses a GMT time zone. The input string is known to start "GMT". 1245 // The function checks whether that is followed by a sign and a number in the 1246 // range -23 through +23 excluding zero. 1247 func parseGMT(value string) int { 1248 value = value[3:] 1249 if len(value) == 0 { 1250 return 3 1251 } 1252 1253 return 3 + parseSignedOffset(value) 1254 } 1255 1256 // parseSignedOffset parses a signed timezone offset (e.g. "+03" or "-04"). 1257 // The function checks for a signed number in the range -23 through +23 excluding zero. 1258 // Returns length of the found offset string or 0 otherwise 1259 func parseSignedOffset(value string) int { 1260 sign := value[0] 1261 if sign != '-' && sign != '+' { 1262 return 0 1263 } 1264 x, rem, err := leadingInt(value[1:]) 1265 1266 // fail if nothing consumed by leadingInt 1267 if err != nil || value[1:] == rem { 1268 return 0 1269 } 1270 if sign == '-' { 1271 x = -x 1272 } 1273 if x < -23 || 23 < x { 1274 return 0 1275 } 1276 return len(value) - len(rem) 1277 } 1278 1279 func parseNanoseconds(value string, nbytes int) (ns int, rangeErrString string, err error) { 1280 if value[0] != '.' { 1281 err = errBad 1282 return 1283 } 1284 if ns, err = atoi(value[1:nbytes]); err != nil { 1285 return 1286 } 1287 if ns < 0 || 1e9 <= ns { 1288 rangeErrString = "fractional second" 1289 return 1290 } 1291 // We need nanoseconds, which means scaling by the number 1292 // of missing digits in the format, maximum length 10. If it's 1293 // longer than 10, we won't scale. 1294 scaleDigits := 10 - nbytes 1295 for i := 0; i < scaleDigits; i++ { 1296 ns *= 10 1297 } 1298 return 1299 } 1300 1301 var errLeadingInt = errors.New("time: bad [0-9]*") // never printed 1302 1303 // leadingInt consumes the leading [0-9]* from s. 1304 func leadingInt(s string) (x int64, rem string, err error) { 1305 i := 0 1306 for ; i < len(s); i++ { 1307 c := s[i] 1308 if c < '0' || c > '9' { 1309 break 1310 } 1311 if x > (1<<63-1)/10 { 1312 // overflow 1313 return 0, "", errLeadingInt 1314 } 1315 x = x*10 + int64(c) - '0' 1316 if x < 0 { 1317 // overflow 1318 return 0, "", errLeadingInt 1319 } 1320 } 1321 return x, s[i:], nil 1322 } 1323 1324 // leadingFraction consumes the leading [0-9]* from s. 1325 // It is used only for fractions, so does not return an error on overflow, 1326 // it just stops accumulating precision. 1327 func leadingFraction(s string) (x int64, scale float64, rem string) { 1328 i := 0 1329 scale = 1 1330 overflow := false 1331 for ; i < len(s); i++ { 1332 c := s[i] 1333 if c < '0' || c > '9' { 1334 break 1335 } 1336 if overflow { 1337 continue 1338 } 1339 if x > (1<<63-1)/10 { 1340 // It's possible for overflow to give a positive number, so take care. 1341 overflow = true 1342 continue 1343 } 1344 y := x*10 + int64(c) - '0' 1345 if y < 0 { 1346 overflow = true 1347 continue 1348 } 1349 x = y 1350 scale *= 10 1351 } 1352 return x, scale, s[i:] 1353 } 1354 1355 var unitMap = map[string]int64{ 1356 "ns": int64(Nanosecond), 1357 "us": int64(Microsecond), 1358 "µs": int64(Microsecond), // U+00B5 = micro symbol 1359 "μs": int64(Microsecond), // U+03BC = Greek letter mu 1360 "ms": int64(Millisecond), 1361 "s": int64(Second), 1362 "m": int64(Minute), 1363 "h": int64(Hour), 1364 } 1365 1366 // ParseDuration parses a duration string. 1367 // A duration string is a possibly signed sequence of 1368 // decimal numbers, each with optional fraction and a unit suffix, 1369 // such as "300ms", "-1.5h" or "2h45m". 1370 // Valid time units are "ns", "us" (or "µs"), "ms", "s", "m", "h". 1371 func ParseDuration(s string) (Duration, error) { 1372 // [-+]?([0-9]*(\.[0-9]*)?[a-z]+)+ 1373 orig := s 1374 var d int64 1375 neg := false 1376 1377 // Consume [-+]? 1378 if s != "" { 1379 c := s[0] 1380 if c == '-' || c == '+' { 1381 neg = c == '-' 1382 s = s[1:] 1383 } 1384 } 1385 // Special case: if all that is left is "0", this is zero. 1386 if s == "0" { 1387 return 0, nil 1388 } 1389 if s == "" { 1390 return 0, errors.New("time: invalid duration " + orig) 1391 } 1392 for s != "" { 1393 var ( 1394 v, f int64 // integers before, after decimal point 1395 scale float64 = 1 // value = v + f/scale 1396 ) 1397 1398 var err error 1399 1400 // The next character must be [0-9.] 1401 if !(s[0] == '.' || '0' <= s[0] && s[0] <= '9') { 1402 return 0, errors.New("time: invalid duration " + orig) 1403 } 1404 // Consume [0-9]* 1405 pl := len(s) 1406 v, s, err = leadingInt(s) 1407 if err != nil { 1408 return 0, errors.New("time: invalid duration " + orig) 1409 } 1410 pre := pl != len(s) // whether we consumed anything before a period 1411 1412 // Consume (\.[0-9]*)? 1413 post := false 1414 if s != "" && s[0] == '.' { 1415 s = s[1:] 1416 pl := len(s) 1417 f, scale, s = leadingFraction(s) 1418 post = pl != len(s) 1419 } 1420 if !pre && !post { 1421 // no digits (e.g. ".s" or "-.s") 1422 return 0, errors.New("time: invalid duration " + orig) 1423 } 1424 1425 // Consume unit. 1426 i := 0 1427 for ; i < len(s); i++ { 1428 c := s[i] 1429 if c == '.' || '0' <= c && c <= '9' { 1430 break 1431 } 1432 } 1433 if i == 0 { 1434 return 0, errors.New("time: missing unit in duration " + orig) 1435 } 1436 u := s[:i] 1437 s = s[i:] 1438 unit, ok := unitMap[u] 1439 if !ok { 1440 return 0, errors.New("time: unknown unit " + u + " in duration " + orig) 1441 } 1442 if v > (1<<63-1)/unit { 1443 // overflow 1444 return 0, errors.New("time: invalid duration " + orig) 1445 } 1446 v *= unit 1447 if f > 0 { 1448 // float64 is needed to be nanosecond accurate for fractions of hours. 1449 // v >= 0 && (f*unit/scale) <= 3.6e+12 (ns/h, h is the largest unit) 1450 v += int64(float64(f) * (float64(unit) / scale)) 1451 if v < 0 { 1452 // overflow 1453 return 0, errors.New("time: invalid duration " + orig) 1454 } 1455 } 1456 d += v 1457 if d < 0 { 1458 // overflow 1459 return 0, errors.New("time: invalid duration " + orig) 1460 } 1461 } 1462 1463 if neg { 1464 d = -d 1465 } 1466 return Duration(d), nil 1467 } 1468
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