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1 /*
2 * Copyright (C) 1999-2000 Harri Porten (porten@kde.org)
3 * Copyright (C) 2006, 2007 Apple Inc. All rights reserved.
4 * Copyright (C) 2009 Google Inc. All rights reserved.
5 * Copyright (C) 2007-2009 Torch Mobile, Inc.
6 * Copyright (C) 2010 &yet, LLC. (nate@andyet.net)
8 * The Original Code is Mozilla Communicator client code, released
9 * March 31, 1998.
11 * The Initial Developer of the Original Code is
12 * Netscape Communications Corporation.
13 * Portions created by the Initial Developer are Copyright (C) 1998
14 * the Initial Developer. All Rights Reserved.
16 * This library is free software; you can redistribute it and/or
17 * modify it under the terms of the GNU Lesser General Public
18 * License as published by the Free Software Foundation; either
19 * version 2.1 of the License, or (at your option) any later version.
21 * This library is distributed in the hope that it will be useful,
22 * but WITHOUT ANY WARRANTY; without even the implied warranty of
23 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
24 * Lesser General Public License for more details.
26 * You should have received a copy of the GNU Lesser General Public
27 * License along with this library; if not, write to the Free Software
28 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
30 * Alternatively, the contents of this file may be used under the terms
31 * of either the Mozilla Public License Version 1.1, found at
32 * http://www.mozilla.org/MPL/ (the "MPL") or the GNU General Public
33 * License Version 2.0, found at http://www.fsf.org/copyleft/gpl.html
34 * (the "GPL"), in which case the provisions of the MPL or the GPL are
35 * applicable instead of those above. If you wish to allow use of your
36 * version of this file only under the terms of one of those two
37 * licenses (the MPL or the GPL) and not to allow others to use your
38 * version of this file under the LGPL, indicate your decision by
39 * deletingthe provisions above and replace them with the notice and
40 * other provisions required by the MPL or the GPL, as the case may be.
41 * If you do not delete the provisions above, a recipient may use your
42 * version of this file under any of the LGPL, the MPL or the GPL.
44 * Copyright 2006-2008 the V8 project authors. All rights reserved.
45 * Redistribution and use in source and binary forms, with or without
46 * modification, are permitted provided that the following conditions are
47 * met:
49 * * Redistributions of source code must retain the above copyright
50 * notice, this list of conditions and the following disclaimer.
51 * * Redistributions in binary form must reproduce the above
52 * copyright notice, this list of conditions and the following
53 * disclaimer in the documentation and/or other materials provided
54 * with the distribution.
55 * * Neither the name of Google Inc. nor the names of its
56 * contributors may be used to endorse or promote products derived
57 * from this software without specific prior written permission.
59 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
60 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
61 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
62 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
63 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
64 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
65 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
66 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
67 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
68 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
69 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
72 #include "config.h"
73 #include "DateMath.h"
75 #include "Assertions.h"
76 #include "ASCIICType.h"
77 #include "CurrentTime.h"
78 #include "MathExtras.h"
79 #include "StdLibExtras.h"
80 #include "StringExtras.h"
82 #include <algorithm>
83 #include <limits.h>
84 #include <limits>
85 #include <math.h>
86 #include <stdlib.h>
87 #include <time.h>
88 #include "wtf/text/StringBuilder.h"
90 #if OS(WIN)
91 #include <windows.h>
92 #endif
94 #if HAVE(SYS_TIME_H)
95 #include <sys/time.h>
96 #endif
98 using namespace WTF;
100 namespace WTF {
102 /* Constants */
104 static const double hoursPerDay = 24.0;
105 static const double secondsPerDay = 24.0 * 60.0 * 60.0;
107 static const double maxUnixTime = 2145859200.0; // 12/31/2037
109 // Day of year for the first day of each month, where index 0 is January, and day 0 is January 1.
110 // First for non-leap years, then for leap years.
111 static const int firstDayOfMonth[2][12] = {
112 {0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334},
113 {0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335}
116 static inline void getLocalTime(const time_t* localTime, struct tm* localTM)
118 #if COMPILER(MSVC)
119 localtime_s(localTM, localTime);
120 #else
121 localtime_r(localTime, localTM);
122 #endif
125 bool isLeapYear(int year)
127 if (year % 4 != 0)
128 return false;
129 if (year % 400 == 0)
130 return true;
131 if (year % 100 == 0)
132 return false;
133 return true;
136 static inline int daysInYear(int year)
138 return 365 + isLeapYear(year);
141 static inline double daysFrom1970ToYear(int year)
143 // The Gregorian Calendar rules for leap years:
144 // Every fourth year is a leap year. 2004, 2008, and 2012 are leap years.
145 // However, every hundredth year is not a leap year. 1900 and 2100 are not leap years.
146 // Every four hundred years, there's a leap year after all. 2000 and 2400 are leap years.
148 static const int leapDaysBefore1971By4Rule = 1970 / 4;
149 static const int excludedLeapDaysBefore1971By100Rule = 1970 / 100;
150 static const int leapDaysBefore1971By400Rule = 1970 / 400;
152 const double yearMinusOne = year - 1;
153 const double yearsToAddBy4Rule = floor(yearMinusOne / 4.0) - leapDaysBefore1971By4Rule;
154 const double yearsToExcludeBy100Rule = floor(yearMinusOne / 100.0) - excludedLeapDaysBefore1971By100Rule;
155 const double yearsToAddBy400Rule = floor(yearMinusOne / 400.0) - leapDaysBefore1971By400Rule;
157 return 365.0 * (year - 1970) + yearsToAddBy4Rule - yearsToExcludeBy100Rule + yearsToAddBy400Rule;
160 static double msToDays(double ms)
162 return floor(ms / msPerDay);
165 static void appendTwoDigitNumber(StringBuilder& builder, int number)
167 ASSERT(number >= 0 && number < 100);
168 if (number <= 9)
169 builder.append('0');
170 builder.appendNumber(number);
173 int msToYear(double ms)
175 int approxYear = static_cast<int>(floor(ms / (msPerDay * 365.2425)) + 1970);
176 double msFromApproxYearTo1970 = msPerDay * daysFrom1970ToYear(approxYear);
177 if (msFromApproxYearTo1970 > ms)
178 return approxYear - 1;
179 if (msFromApproxYearTo1970 + msPerDay * daysInYear(approxYear) <= ms)
180 return approxYear + 1;
181 return approxYear;
184 int dayInYear(double ms, int year)
186 return static_cast<int>(msToDays(ms) - daysFrom1970ToYear(year));
189 static inline double msToMilliseconds(double ms)
191 double result = fmod(ms, msPerDay);
192 if (result < 0)
193 result += msPerDay;
194 return result;
197 int monthFromDayInYear(int dayInYear, bool leapYear)
199 const int d = dayInYear;
200 int step;
202 if (d < (step = 31))
203 return 0;
204 step += (leapYear ? 29 : 28);
205 if (d < step)
206 return 1;
207 if (d < (step += 31))
208 return 2;
209 if (d < (step += 30))
210 return 3;
211 if (d < (step += 31))
212 return 4;
213 if (d < (step += 30))
214 return 5;
215 if (d < (step += 31))
216 return 6;
217 if (d < (step += 31))
218 return 7;
219 if (d < (step += 30))
220 return 8;
221 if (d < (step += 31))
222 return 9;
223 if (d < (step += 30))
224 return 10;
225 return 11;
228 static inline bool checkMonth(int dayInYear, int& startDayOfThisMonth, int& startDayOfNextMonth, int daysInThisMonth)
230 startDayOfThisMonth = startDayOfNextMonth;
231 startDayOfNextMonth += daysInThisMonth;
232 return (dayInYear <= startDayOfNextMonth);
235 int dayInMonthFromDayInYear(int dayInYear, bool leapYear)
237 const int d = dayInYear;
238 int step;
239 int next = 30;
241 if (d <= next)
242 return d + 1;
243 const int daysInFeb = (leapYear ? 29 : 28);
244 if (checkMonth(d, step, next, daysInFeb))
245 return d - step;
246 if (checkMonth(d, step, next, 31))
247 return d - step;
248 if (checkMonth(d, step, next, 30))
249 return d - step;
250 if (checkMonth(d, step, next, 31))
251 return d - step;
252 if (checkMonth(d, step, next, 30))
253 return d - step;
254 if (checkMonth(d, step, next, 31))
255 return d - step;
256 if (checkMonth(d, step, next, 31))
257 return d - step;
258 if (checkMonth(d, step, next, 30))
259 return d - step;
260 if (checkMonth(d, step, next, 31))
261 return d - step;
262 if (checkMonth(d, step, next, 30))
263 return d - step;
264 step = next;
265 return d - step;
268 int dayInYear(int year, int month, int day)
270 return firstDayOfMonth[isLeapYear(year)][month] + day - 1;
273 double dateToDaysFrom1970(int year, int month, int day)
275 year += month / 12;
277 month %= 12;
278 if (month < 0) {
279 month += 12;
280 --year;
283 double yearday = floor(daysFrom1970ToYear(year));
284 ASSERT((year >= 1970 && yearday >= 0) || (year < 1970 && yearday < 0));
285 return yearday + dayInYear(year, month, day);
288 // There is a hard limit at 2038 that we currently do not have a workaround
289 // for (rdar://problem/5052975).
290 static inline int maximumYearForDST()
292 return 2037;
295 static inline double jsCurrentTime()
297 // JavaScript doesn't recognize fractions of a millisecond.
298 return floor(WTF::currentTimeMS());
301 static inline int minimumYearForDST()
303 // Because of the 2038 issue (see maximumYearForDST) if the current year is
304 // greater than the max year minus 27 (2010), we want to use the max year
305 // minus 27 instead, to ensure there is a range of 28 years that all years
306 // can map to.
307 return std::min(msToYear(jsCurrentTime()), maximumYearForDST() - 27) ;
311 * Find an equivalent year for the one given, where equivalence is deterined by
312 * the two years having the same leapness and the first day of the year, falling
313 * on the same day of the week.
315 * This function returns a year between this current year and 2037, however this
316 * function will potentially return incorrect results if the current year is after
317 * 2010, (rdar://problem/5052975), if the year passed in is before 1900 or after
318 * 2100, (rdar://problem/5055038).
320 static int equivalentYearForDST(int year)
322 // It is ok if the cached year is not the current year as long as the rules
323 // for DST did not change between the two years; if they did the app would need
324 // to be restarted.
325 static int minYear = minimumYearForDST();
326 int maxYear = maximumYearForDST();
328 int difference;
329 if (year > maxYear)
330 difference = minYear - year;
331 else if (year < minYear)
332 difference = maxYear - year;
333 else
334 return year;
336 int quotient = difference / 28;
337 int product = (quotient) * 28;
339 year += product;
340 ASSERT((year >= minYear && year <= maxYear) || (product - year == static_cast<int>(std::numeric_limits<double>::quiet_NaN())));
341 return year;
344 static double calculateUTCOffset()
346 #if OS(WIN)
347 TIME_ZONE_INFORMATION timeZoneInformation;
348 GetTimeZoneInformation(&timeZoneInformation);
349 int32_t bias = timeZoneInformation.Bias + timeZoneInformation.StandardBias;
350 return -bias * 60 * 1000;
351 #else
352 time_t localTime = time(0);
353 tm localt;
354 getLocalTime(&localTime, &localt);
356 // tm_gmtoff includes any daylight savings offset, so subtract it.
357 return static_cast<double>(localt.tm_gmtoff * msPerSecond - (localt.tm_isdst > 0 ? msPerHour : 0));
358 #endif
362 * Get the DST offset for the time passed in.
364 static double calculateDSTOffsetSimple(double localTimeSeconds, double utcOffset)
366 if (localTimeSeconds > maxUnixTime)
367 localTimeSeconds = maxUnixTime;
368 else if (localTimeSeconds < 0) // Go ahead a day to make localtime work (does not work with 0)
369 localTimeSeconds += secondsPerDay;
371 // FIXME: time_t has a potential problem in 2038
372 time_t localTime = static_cast<time_t>(localTimeSeconds);
374 tm localTM;
375 getLocalTime(&localTime, &localTM);
377 return localTM.tm_isdst > 0 ? msPerHour : 0;
380 // Get the DST offset, given a time in UTC
381 static double calculateDSTOffset(double ms, double utcOffset)
383 // On Mac OS X, the call to localtime (see calculateDSTOffsetSimple) will return historically accurate
384 // DST information (e.g. New Zealand did not have DST from 1946 to 1974) however the JavaScript
385 // standard explicitly dictates that historical information should not be considered when
386 // determining DST. For this reason we shift away from years that localtime can handle but would
387 // return historically accurate information.
388 int year = msToYear(ms);
389 int equivalentYear = equivalentYearForDST(year);
390 if (year != equivalentYear) {
391 bool leapYear = isLeapYear(year);
392 int dayInYearLocal = dayInYear(ms, year);
393 int dayInMonth = dayInMonthFromDayInYear(dayInYearLocal, leapYear);
394 int month = monthFromDayInYear(dayInYearLocal, leapYear);
395 double day = dateToDaysFrom1970(equivalentYear, month, dayInMonth);
396 ms = (day * msPerDay) + msToMilliseconds(ms);
399 return calculateDSTOffsetSimple(ms / msPerSecond, utcOffset);
402 void initializeDates()
404 #if ENABLE(ASSERT)
405 static bool alreadyInitialized;
406 ASSERT(!alreadyInitialized);
407 alreadyInitialized = true;
408 #endif
410 equivalentYearForDST(2000); // Need to call once to initialize a static used in this function.
413 static inline double ymdhmsToSeconds(int year, long mon, long day, long hour, long minute, double second)
415 double days = (day - 32075)
416 + floor(1461 * (year + 4800.0 + (mon - 14) / 12) / 4)
417 + 367 * (mon - 2 - (mon - 14) / 12 * 12) / 12
418 - floor(3 * ((year + 4900.0 + (mon - 14) / 12) / 100) / 4)
419 - 2440588;
420 return ((days * hoursPerDay + hour) * minutesPerHour + minute) * secondsPerMinute + second;
423 // We follow the recommendation of RFC 2822 to consider all
424 // obsolete time zones not listed here equivalent to "-0000".
425 static const struct KnownZone {
426 #if !OS(WIN)
427 const
428 #endif
429 char tzName[4];
430 int tzOffset;
431 } known_zones[] = {
432 { "UT", 0 },
433 { "GMT", 0 },
434 { "EST", -300 },
435 { "EDT", -240 },
436 { "CST", -360 },
437 { "CDT", -300 },
438 { "MST", -420 },
439 { "MDT", -360 },
440 { "PST", -480 },
441 { "PDT", -420 }
444 inline static void skipSpacesAndComments(const char*& s)
446 int nesting = 0;
447 char ch;
448 while ((ch = *s)) {
449 if (!isASCIISpace(ch)) {
450 if (ch == '(')
451 nesting++;
452 else if (ch == ')' && nesting > 0)
453 nesting--;
454 else if (nesting == 0)
455 break;
457 s++;
461 // returns 0-11 (Jan-Dec); -1 on failure
462 static int findMonth(const char* monthStr)
464 ASSERT(monthStr);
465 char needle[4];
466 for (int i = 0; i < 3; ++i) {
467 if (!*monthStr)
468 return -1;
469 needle[i] = static_cast<char>(toASCIILower(*monthStr++));
471 needle[3] = '\0';
472 const char *haystack = "janfebmaraprmayjunjulaugsepoctnovdec";
473 const char *str = strstr(haystack, needle);
474 if (str) {
475 int position = static_cast<int>(str - haystack);
476 if (position % 3 == 0)
477 return position / 3;
479 return -1;
482 static bool parseInt(const char* string, char** stopPosition, int base, int* result)
484 long longResult = strtol(string, stopPosition, base);
485 // Avoid the use of errno as it is not available on Windows CE
486 if (string == *stopPosition || longResult <= std::numeric_limits<int>::min() || longResult >= std::numeric_limits<int>::max())
487 return false;
488 *result = static_cast<int>(longResult);
489 return true;
492 static bool parseLong(const char* string, char** stopPosition, int base, long* result)
494 *result = strtol(string, stopPosition, base);
495 // Avoid the use of errno as it is not available on Windows CE
496 if (string == *stopPosition || *result == std::numeric_limits<long>::min() || *result == std::numeric_limits<long>::max())
497 return false;
498 return true;
501 // Odd case where 'exec' is allowed to be 0, to accomodate a caller in WebCore.
502 static double parseDateFromNullTerminatedCharacters(const char* dateString, bool& haveTZ, int& offset)
504 haveTZ = false;
505 offset = 0;
507 // This parses a date in the form:
508 // Tuesday, 09-Nov-99 23:12:40 GMT
509 // or
510 // Sat, 01-Jan-2000 08:00:00 GMT
511 // or
512 // Sat, 01 Jan 2000 08:00:00 GMT
513 // or
514 // 01 Jan 99 22:00 +0100 (exceptions in rfc822/rfc2822)
515 // ### non RFC formats, added for Javascript:
516 // [Wednesday] January 09 1999 23:12:40 GMT
517 // [Wednesday] January 09 23:12:40 GMT 1999
519 // We ignore the weekday.
521 // Skip leading space
522 skipSpacesAndComments(dateString);
524 long month = -1;
525 const char *wordStart = dateString;
526 // Check contents of first words if not number
527 while (*dateString && !isASCIIDigit(*dateString)) {
528 if (isASCIISpace(*dateString) || *dateString == '(') {
529 if (dateString - wordStart >= 3)
530 month = findMonth(wordStart);
531 skipSpacesAndComments(dateString);
532 wordStart = dateString;
533 } else
534 dateString++;
537 // Missing delimiter between month and day (like "January29")?
538 if (month == -1 && wordStart != dateString)
539 month = findMonth(wordStart);
541 skipSpacesAndComments(dateString);
543 if (!*dateString)
544 return std::numeric_limits<double>::quiet_NaN();
546 // ' 09-Nov-99 23:12:40 GMT'
547 char* newPosStr;
548 long day;
549 if (!parseLong(dateString, &newPosStr, 10, &day))
550 return std::numeric_limits<double>::quiet_NaN();
551 dateString = newPosStr;
553 if (!*dateString)
554 return std::numeric_limits<double>::quiet_NaN();
556 if (day < 0)
557 return std::numeric_limits<double>::quiet_NaN();
559 int year = 0;
560 if (day > 31) {
561 // ### where is the boundary and what happens below?
562 if (*dateString != '/')
563 return std::numeric_limits<double>::quiet_NaN();
564 // looks like a YYYY/MM/DD date
565 if (!*++dateString)
566 return std::numeric_limits<double>::quiet_NaN();
567 if (day <= std::numeric_limits<int>::min() || day >= std::numeric_limits<int>::max())
568 return std::numeric_limits<double>::quiet_NaN();
569 year = static_cast<int>(day);
570 if (!parseLong(dateString, &newPosStr, 10, &month))
571 return std::numeric_limits<double>::quiet_NaN();
572 month -= 1;
573 dateString = newPosStr;
574 if (*dateString++ != '/' || !*dateString)
575 return std::numeric_limits<double>::quiet_NaN();
576 if (!parseLong(dateString, &newPosStr, 10, &day))
577 return std::numeric_limits<double>::quiet_NaN();
578 dateString = newPosStr;
579 } else if (*dateString == '/' && month == -1) {
580 dateString++;
581 // This looks like a MM/DD/YYYY date, not an RFC date.
582 month = day - 1; // 0-based
583 if (!parseLong(dateString, &newPosStr, 10, &day))
584 return std::numeric_limits<double>::quiet_NaN();
585 if (day < 1 || day > 31)
586 return std::numeric_limits<double>::quiet_NaN();
587 dateString = newPosStr;
588 if (*dateString == '/')
589 dateString++;
590 if (!*dateString)
591 return std::numeric_limits<double>::quiet_NaN();
592 } else {
593 if (*dateString == '-')
594 dateString++;
596 skipSpacesAndComments(dateString);
598 if (*dateString == ',')
599 dateString++;
601 if (month == -1) { // not found yet
602 month = findMonth(dateString);
603 if (month == -1)
604 return std::numeric_limits<double>::quiet_NaN();
606 while (*dateString && *dateString != '-' && *dateString != ',' && !isASCIISpace(*dateString))
607 dateString++;
609 if (!*dateString)
610 return std::numeric_limits<double>::quiet_NaN();
612 // '-99 23:12:40 GMT'
613 if (*dateString != '-' && *dateString != '/' && *dateString != ',' && !isASCIISpace(*dateString))
614 return std::numeric_limits<double>::quiet_NaN();
615 dateString++;
619 if (month < 0 || month > 11)
620 return std::numeric_limits<double>::quiet_NaN();
622 // '99 23:12:40 GMT'
623 if (year <= 0 && *dateString) {
624 if (!parseInt(dateString, &newPosStr, 10, &year))
625 return std::numeric_limits<double>::quiet_NaN();
628 // Don't fail if the time is missing.
629 long hour = 0;
630 long minute = 0;
631 long second = 0;
632 if (!*newPosStr)
633 dateString = newPosStr;
634 else {
635 // ' 23:12:40 GMT'
636 if (!(isASCIISpace(*newPosStr) || *newPosStr == ',')) {
637 if (*newPosStr != ':')
638 return std::numeric_limits<double>::quiet_NaN();
639 // There was no year; the number was the hour.
640 year = -1;
641 } else {
642 // in the normal case (we parsed the year), advance to the next number
643 dateString = ++newPosStr;
644 skipSpacesAndComments(dateString);
647 parseLong(dateString, &newPosStr, 10, &hour);
648 // Do not check for errno here since we want to continue
649 // even if errno was set becasue we are still looking
650 // for the timezone!
652 // Read a number? If not, this might be a timezone name.
653 if (newPosStr != dateString) {
654 dateString = newPosStr;
656 if (hour < 0 || hour > 23)
657 return std::numeric_limits<double>::quiet_NaN();
659 if (!*dateString)
660 return std::numeric_limits<double>::quiet_NaN();
662 // ':12:40 GMT'
663 if (*dateString++ != ':')
664 return std::numeric_limits<double>::quiet_NaN();
666 if (!parseLong(dateString, &newPosStr, 10, &minute))
667 return std::numeric_limits<double>::quiet_NaN();
668 dateString = newPosStr;
670 if (minute < 0 || minute > 59)
671 return std::numeric_limits<double>::quiet_NaN();
673 // ':40 GMT'
674 if (*dateString && *dateString != ':' && !isASCIISpace(*dateString))
675 return std::numeric_limits<double>::quiet_NaN();
677 // seconds are optional in rfc822 + rfc2822
678 if (*dateString ==':') {
679 dateString++;
681 if (!parseLong(dateString, &newPosStr, 10, &second))
682 return std::numeric_limits<double>::quiet_NaN();
683 dateString = newPosStr;
685 if (second < 0 || second > 59)
686 return std::numeric_limits<double>::quiet_NaN();
689 skipSpacesAndComments(dateString);
691 if (strncasecmp(dateString, "AM", 2) == 0) {
692 if (hour > 12)
693 return std::numeric_limits<double>::quiet_NaN();
694 if (hour == 12)
695 hour = 0;
696 dateString += 2;
697 skipSpacesAndComments(dateString);
698 } else if (strncasecmp(dateString, "PM", 2) == 0) {
699 if (hour > 12)
700 return std::numeric_limits<double>::quiet_NaN();
701 if (hour != 12)
702 hour += 12;
703 dateString += 2;
704 skipSpacesAndComments(dateString);
709 // The year may be after the time but before the time zone.
710 if (isASCIIDigit(*dateString) && year == -1) {
711 if (!parseInt(dateString, &newPosStr, 10, &year))
712 return std::numeric_limits<double>::quiet_NaN();
713 dateString = newPosStr;
714 skipSpacesAndComments(dateString);
717 // Don't fail if the time zone is missing.
718 // Some websites omit the time zone (4275206).
719 if (*dateString) {
720 if (strncasecmp(dateString, "GMT", 3) == 0 || strncasecmp(dateString, "UTC", 3) == 0) {
721 dateString += 3;
722 haveTZ = true;
725 if (*dateString == '+' || *dateString == '-') {
726 int o;
727 if (!parseInt(dateString, &newPosStr, 10, &o))
728 return std::numeric_limits<double>::quiet_NaN();
729 dateString = newPosStr;
731 if (o < -9959 || o > 9959)
732 return std::numeric_limits<double>::quiet_NaN();
734 int sgn = (o < 0) ? -1 : 1;
735 o = abs(o);
736 if (*dateString != ':') {
737 if (o >= 24)
738 offset = ((o / 100) * 60 + (o % 100)) * sgn;
739 else
740 offset = o * 60 * sgn;
741 } else { // GMT+05:00
742 ++dateString; // skip the ':'
743 int o2;
744 if (!parseInt(dateString, &newPosStr, 10, &o2))
745 return std::numeric_limits<double>::quiet_NaN();
746 dateString = newPosStr;
747 offset = (o * 60 + o2) * sgn;
749 haveTZ = true;
750 } else {
751 for (size_t i = 0; i < WTF_ARRAY_LENGTH(known_zones); ++i) {
752 if (0 == strncasecmp(dateString, known_zones[i].tzName, strlen(known_zones[i].tzName))) {
753 offset = known_zones[i].tzOffset;
754 dateString += strlen(known_zones[i].tzName);
755 haveTZ = true;
756 break;
762 skipSpacesAndComments(dateString);
764 if (*dateString && year == -1) {
765 if (!parseInt(dateString, &newPosStr, 10, &year))
766 return std::numeric_limits<double>::quiet_NaN();
767 dateString = newPosStr;
768 skipSpacesAndComments(dateString);
771 // Trailing garbage
772 if (*dateString)
773 return std::numeric_limits<double>::quiet_NaN();
775 // Y2K: Handle 2 digit years.
776 if (year >= 0 && year < 100) {
777 if (year < 50)
778 year += 2000;
779 else
780 year += 1900;
783 return ymdhmsToSeconds(year, month + 1, day, hour, minute, second) * msPerSecond;
786 double parseDateFromNullTerminatedCharacters(const char* dateString)
788 bool haveTZ;
789 int offset;
790 double ms = parseDateFromNullTerminatedCharacters(dateString, haveTZ, offset);
791 if (std::isnan(ms))
792 return std::numeric_limits<double>::quiet_NaN();
794 // fall back to local timezone
795 if (!haveTZ) {
796 double utcOffset = calculateUTCOffset();
797 double dstOffset = calculateDSTOffset(ms, utcOffset);
798 offset = static_cast<int>((utcOffset + dstOffset) / msPerMinute);
800 return ms - (offset * msPerMinute);
803 // See http://tools.ietf.org/html/rfc2822#section-3.3 for more information.
804 String makeRFC2822DateString(unsigned dayOfWeek, unsigned day, unsigned month, unsigned year, unsigned hours, unsigned minutes, unsigned seconds, int utcOffset)
806 StringBuilder stringBuilder;
807 stringBuilder.append(weekdayName[dayOfWeek]);
808 stringBuilder.appendLiteral(", ");
809 stringBuilder.appendNumber(day);
810 stringBuilder.append(' ');
811 stringBuilder.append(monthName[month]);
812 stringBuilder.append(' ');
813 stringBuilder.appendNumber(year);
814 stringBuilder.append(' ');
816 appendTwoDigitNumber(stringBuilder, hours);
817 stringBuilder.append(':');
818 appendTwoDigitNumber(stringBuilder, minutes);
819 stringBuilder.append(':');
820 appendTwoDigitNumber(stringBuilder, seconds);
821 stringBuilder.append(' ');
823 stringBuilder.append(utcOffset > 0 ? '+' : '-');
824 int absoluteUTCOffset = abs(utcOffset);
825 appendTwoDigitNumber(stringBuilder, absoluteUTCOffset / 60);
826 appendTwoDigitNumber(stringBuilder, absoluteUTCOffset % 60);
828 return stringBuilder.toString();
831 double convertToLocalTime(double ms)
833 double utcOffset = calculateUTCOffset();
834 double dstOffset = calculateDSTOffset(ms, utcOffset);
835 return (ms + utcOffset + dstOffset);
838 } // namespace WTF