source: webkit/trunk/JavaScriptCore/wtf/DateMath.cpp@ 57853

Last change on this file since 57853 was 53921, checked in by [email protected], 15 years ago

2010-01-27 Kwang Yul Seo <​[email protected]>

Reviewed by Eric Seidel.

[BREWMP] Don't use time function
​https://bugs.webkit.org/show_bug.cgi?id=33577

Calling time(0) in BREW devices causes a crash because time
is not properly ported in most devices. Cast currentTime() to
time_t to get the same result as time(0).

  • wtf/DateMath.cpp: (WTF::calculateUTCOffset):
  • Property svn:eol-style set to native
File size: 31.0 KB
Line 
1/*
2 * Copyright (C) 1999-2000 Harri Porten ([email protected])
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 *
7 * The Original Code is Mozilla Communicator client code, released
8 * March 31, 1998.
9 *
10 * The Initial Developer of the Original Code is
11 * Netscape Communications Corporation.
12 * Portions created by the Initial Developer are Copyright (C) 1998
13 * the Initial Developer. All Rights Reserved.
14 *
15 * This library is free software; you can redistribute it and/or
16 * modify it under the terms of the GNU Lesser General Public
17 * License as published by the Free Software Foundation; either
18 * version 2.1 of the License, or (at your option) any later version.
19 *
20 * This library is distributed in the hope that it will be useful,
21 * but WITHOUT ANY WARRANTY; without even the implied warranty of
22 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
23 * Lesser General Public License for more details.
24 *
25 * You should have received a copy of the GNU Lesser General Public
26 * License along with this library; if not, write to the Free Software
27 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
28 *
29 * Alternatively, the contents of this file may be used under the terms
30 * of either the Mozilla Public License Version 1.1, found at
31 * http://www.mozilla.org/MPL/ (the "MPL") or the GNU General Public
32 * License Version 2.0, found at http://www.fsf.org/copyleft/gpl.html
33 * (the "GPL"), in which case the provisions of the MPL or the GPL are
34 * applicable instead of those above. If you wish to allow use of your
35 * version of this file only under the terms of one of those two
36 * licenses (the MPL or the GPL) and not to allow others to use your
37 * version of this file under the LGPL, indicate your decision by
38 * deletingthe provisions above and replace them with the notice and
39 * other provisions required by the MPL or the GPL, as the case may be.
40 * If you do not delete the provisions above, a recipient may use your
41 * version of this file under any of the LGPL, the MPL or the GPL.
42
43 * Copyright 2006-2008 the V8 project authors. All rights reserved.
44 * Redistribution and use in source and binary forms, with or without
45 * modification, are permitted provided that the following conditions are
46 * met:
47 *
48 * * Redistributions of source code must retain the above copyright
49 * notice, this list of conditions and the following disclaimer.
50 * * Redistributions in binary form must reproduce the above
51 * copyright notice, this list of conditions and the following
52 * disclaimer in the documentation and/or other materials provided
53 * with the distribution.
54 * * Neither the name of Google Inc. nor the names of its
55 * contributors may be used to endorse or promote products derived
56 * from this software without specific prior written permission.
57 *
58 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
59 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
60 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
61 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
62 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
63 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
64 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
65 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
66 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
67 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
68 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
69 */
70
71#include "config.h"
72#include "DateMath.h"
73
74#include "Assertions.h"
75#include "ASCIICType.h"
76#include "CurrentTime.h"
77#include "MathExtras.h"
78#include "StringExtras.h"
79
80#include <algorithm>
81#include <limits.h>
82#include <limits>
83#include <stdint.h>
84#include <time.h>
85
86
87#if HAVE(ERRNO_H)
88#include <errno.h>
89#endif
90
91#if OS(WINCE)
92extern "C" size_t strftime(char * const s, const size_t maxsize, const char * const format, const struct tm * const t);
93extern "C" struct tm * localtime(const time_t *timer);
94#endif
95
96#if HAVE(SYS_TIME_H)
97#include <sys/time.h>
98#endif
99
100#if HAVE(SYS_TIMEB_H)
101#include <sys/timeb.h>
102#endif
103
104#if USE(JSC)
105#include "CallFrame.h"
106#endif
107
108#define NaN std::numeric_limits<double>::quiet_NaN()
109
110using namespace WTF;
111
112namespace WTF {
113
114/* Constants */
115
116static const double minutesPerDay = 24.0 * 60.0;
117static const double secondsPerDay = 24.0 * 60.0 * 60.0;
118static const double secondsPerYear = 24.0 * 60.0 * 60.0 * 365.0;
119
120static const double usecPerSec = 1000000.0;
121
122static const double maxUnixTime = 2145859200.0; // 12/31/2037
123// ECMAScript asks not to support for a date of which total
124// millisecond value is larger than the following value.
125// See 15.9.1.14 of ECMA-262 5th edition.
126static const double maxECMAScriptTime = 8.64E15;
127
128// Day of year for the first day of each month, where index 0 is January, and day 0 is January 1.
129// First for non-leap years, then for leap years.
130static const int firstDayOfMonth[2][12] = {
131 {0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334},
132 {0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335}
133};
134
135static inline bool isLeapYear(int year)
136{
137 if (year % 4 != 0)
138 return false;
139 if (year % 400 == 0)
140 return true;
141 if (year % 100 == 0)
142 return false;
143 return true;
144}
145
146static inline int daysInYear(int year)
147{
148 return 365 + isLeapYear(year);
149}
150
151static inline double daysFrom1970ToYear(int year)
152{
153 // The Gregorian Calendar rules for leap years:
154 // Every fourth year is a leap year. 2004, 2008, and 2012 are leap years.
155 // However, every hundredth year is not a leap year. 1900 and 2100 are not leap years.
156 // Every four hundred years, there's a leap year after all. 2000 and 2400 are leap years.
157
158 static const int leapDaysBefore1971By4Rule = 1970 / 4;
159 static const int excludedLeapDaysBefore1971By100Rule = 1970 / 100;
160 static const int leapDaysBefore1971By400Rule = 1970 / 400;
161
162 const double yearMinusOne = year - 1;
163 const double yearsToAddBy4Rule = floor(yearMinusOne / 4.0) - leapDaysBefore1971By4Rule;
164 const double yearsToExcludeBy100Rule = floor(yearMinusOne / 100.0) - excludedLeapDaysBefore1971By100Rule;
165 const double yearsToAddBy400Rule = floor(yearMinusOne / 400.0) - leapDaysBefore1971By400Rule;
166
167 return 365.0 * (year - 1970) + yearsToAddBy4Rule - yearsToExcludeBy100Rule + yearsToAddBy400Rule;
168}
169
170static inline double msToDays(double ms)
171{
172 return floor(ms / msPerDay);
173}
174
175int msToYear(double ms)
176{
177 int approxYear = static_cast<int>(floor(ms / (msPerDay * 365.2425)) + 1970);
178 double msFromApproxYearTo1970 = msPerDay * daysFrom1970ToYear(approxYear);
179 if (msFromApproxYearTo1970 > ms)
180 return approxYear - 1;
181 if (msFromApproxYearTo1970 + msPerDay * daysInYear(approxYear) <= ms)
182 return approxYear + 1;
183 return approxYear;
184}
185
186int dayInYear(double ms, int year)
187{
188 return static_cast<int>(msToDays(ms) - daysFrom1970ToYear(year));
189}
190
191static inline double msToMilliseconds(double ms)
192{
193 double result = fmod(ms, msPerDay);
194 if (result < 0)
195 result += msPerDay;
196 return result;
197}
198
199// 0: Sunday, 1: Monday, etc.
200static inline int msToWeekDay(double ms)
201{
202 int wd = (static_cast<int>(msToDays(ms)) + 4) % 7;
203 if (wd < 0)
204 wd += 7;
205 return wd;
206}
207
208static inline int msToSeconds(double ms)
209{
210 double result = fmod(floor(ms / msPerSecond), secondsPerMinute);
211 if (result < 0)
212 result += secondsPerMinute;
213 return static_cast<int>(result);
214}
215
216static inline int msToMinutes(double ms)
217{
218 double result = fmod(floor(ms / msPerMinute), minutesPerHour);
219 if (result < 0)
220 result += minutesPerHour;
221 return static_cast<int>(result);
222}
223
224static inline int msToHours(double ms)
225{
226 double result = fmod(floor(ms/msPerHour), hoursPerDay);
227 if (result < 0)
228 result += hoursPerDay;
229 return static_cast<int>(result);
230}
231
232int monthFromDayInYear(int dayInYear, bool leapYear)
233{
234 const int d = dayInYear;
235 int step;
236
237 if (d < (step = 31))
238 return 0;
239 step += (leapYear ? 29 : 28);
240 if (d < step)
241 return 1;
242 if (d < (step += 31))
243 return 2;
244 if (d < (step += 30))
245 return 3;
246 if (d < (step += 31))
247 return 4;
248 if (d < (step += 30))
249 return 5;
250 if (d < (step += 31))
251 return 6;
252 if (d < (step += 31))
253 return 7;
254 if (d < (step += 30))
255 return 8;
256 if (d < (step += 31))
257 return 9;
258 if (d < (step += 30))
259 return 10;
260 return 11;
261}
262
263static inline bool checkMonth(int dayInYear, int& startDayOfThisMonth, int& startDayOfNextMonth, int daysInThisMonth)
264{
265 startDayOfThisMonth = startDayOfNextMonth;
266 startDayOfNextMonth += daysInThisMonth;
267 return (dayInYear <= startDayOfNextMonth);
268}
269
270int dayInMonthFromDayInYear(int dayInYear, bool leapYear)
271{
272 const int d = dayInYear;
273 int step;
274 int next = 30;
275
276 if (d <= next)
277 return d + 1;
278 const int daysInFeb = (leapYear ? 29 : 28);
279 if (checkMonth(d, step, next, daysInFeb))
280 return d - step;
281 if (checkMonth(d, step, next, 31))
282 return d - step;
283 if (checkMonth(d, step, next, 30))
284 return d - step;
285 if (checkMonth(d, step, next, 31))
286 return d - step;
287 if (checkMonth(d, step, next, 30))
288 return d - step;
289 if (checkMonth(d, step, next, 31))
290 return d - step;
291 if (checkMonth(d, step, next, 31))
292 return d - step;
293 if (checkMonth(d, step, next, 30))
294 return d - step;
295 if (checkMonth(d, step, next, 31))
296 return d - step;
297 if (checkMonth(d, step, next, 30))
298 return d - step;
299 step = next;
300 return d - step;
301}
302
303static inline int monthToDayInYear(int month, bool isLeapYear)
304{
305 return firstDayOfMonth[isLeapYear][month];
306}
307
308static inline double timeToMS(double hour, double min, double sec, double ms)
309{
310 return (((hour * minutesPerHour + min) * secondsPerMinute + sec) * msPerSecond + ms);
311}
312
313double dateToDaysFrom1970(int year, int month, int day)
314{
315 year += month / 12;
316
317 month %= 12;
318 if (month < 0) {
319 month += 12;
320 --year;
321 }
322
323 double yearday = floor(daysFrom1970ToYear(year));
324 ASSERT((year >= 1970 && yearday >= 0) || (year < 1970 && yearday < 0));
325 int monthday = monthToDayInYear(month, isLeapYear(year));
326
327 return yearday + monthday + day - 1;
328}
329
330// There is a hard limit at 2038 that we currently do not have a workaround
331// for (rdar://problem/5052975).
332static inline int maximumYearForDST()
333{
334 return 2037;
335}
336
337static inline int minimumYearForDST()
338{
339 // Because of the 2038 issue (see maximumYearForDST) if the current year is
340 // greater than the max year minus 27 (2010), we want to use the max year
341 // minus 27 instead, to ensure there is a range of 28 years that all years
342 // can map to.
343 return std::min(msToYear(jsCurrentTime()), maximumYearForDST() - 27) ;
344}
345
346/*
347 * Find an equivalent year for the one given, where equivalence is deterined by
348 * the two years having the same leapness and the first day of the year, falling
349 * on the same day of the week.
350 *
351 * This function returns a year between this current year and 2037, however this
352 * function will potentially return incorrect results if the current year is after
353 * 2010, (rdar://problem/5052975), if the year passed in is before 1900 or after
354 * 2100, (rdar://problem/5055038).
355 */
356int equivalentYearForDST(int year)
357{
358 // It is ok if the cached year is not the current year as long as the rules
359 // for DST did not change between the two years; if they did the app would need
360 // to be restarted.
361 static int minYear = minimumYearForDST();
362 int maxYear = maximumYearForDST();
363
364 int difference;
365 if (year > maxYear)
366 difference = minYear - year;
367 else if (year < minYear)
368 difference = maxYear - year;
369 else
370 return year;
371
372 int quotient = difference / 28;
373 int product = (quotient) * 28;
374
375 year += product;
376 ASSERT((year >= minYear && year <= maxYear) || (product - year == static_cast<int>(NaN)));
377 return year;
378}
379
380static int32_t calculateUTCOffset()
381{
382#if PLATFORM(BREWMP)
383 time_t localTime = static_cast<time_t>(currentTime());
384#else
385 time_t localTime = time(0);
386#endif
387 tm localt;
388 getLocalTime(&localTime, &localt);
389
390 // Get the difference between this time zone and UTC on the 1st of January of this year.
391 localt.tm_sec = 0;
392 localt.tm_min = 0;
393 localt.tm_hour = 0;
394 localt.tm_mday = 1;
395 localt.tm_mon = 0;
396 // Not setting localt.tm_year!
397 localt.tm_wday = 0;
398 localt.tm_yday = 0;
399 localt.tm_isdst = 0;
400#if HAVE(TM_GMTOFF)
401 localt.tm_gmtoff = 0;
402#endif
403#if HAVE(TM_ZONE)
404 localt.tm_zone = 0;
405#endif
406
407#if HAVE(TIMEGM)
408 time_t utcOffset = timegm(&localt) - mktime(&localt);
409#else
410 // Using a canned date of 01/01/2009 on platforms with weaker date-handling foo.
411 localt.tm_year = 109;
412 time_t utcOffset = 1230768000 - mktime(&localt);
413#endif
414
415 return static_cast<int32_t>(utcOffset * 1000);
416}
417
418/*
419 * Get the DST offset for the time passed in.
420 */
421static double calculateDSTOffsetSimple(double localTimeSeconds, double utcOffset)
422{
423 if (localTimeSeconds > maxUnixTime)
424 localTimeSeconds = maxUnixTime;
425 else if (localTimeSeconds < 0) // Go ahead a day to make localtime work (does not work with 0)
426 localTimeSeconds += secondsPerDay;
427
428 //input is UTC so we have to shift back to local time to determine DST thus the + getUTCOffset()
429 double offsetTime = (localTimeSeconds * msPerSecond) + utcOffset;
430
431 // Offset from UTC but doesn't include DST obviously
432 int offsetHour = msToHours(offsetTime);
433 int offsetMinute = msToMinutes(offsetTime);
434
435 // FIXME: time_t has a potential problem in 2038
436 time_t localTime = static_cast<time_t>(localTimeSeconds);
437
438 tm localTM;
439 getLocalTime(&localTime, &localTM);
440
441 double diff = ((localTM.tm_hour - offsetHour) * secondsPerHour) + ((localTM.tm_min - offsetMinute) * 60);
442
443 if (diff < 0)
444 diff += secondsPerDay;
445
446 return (diff * msPerSecond);
447}
448
449// Get the DST offset, given a time in UTC
450static double calculateDSTOffset(double ms, double utcOffset)
451{
452 // On Mac OS X, the call to localtime (see calculateDSTOffsetSimple) will return historically accurate
453 // DST information (e.g. New Zealand did not have DST from 1946 to 1974) however the JavaScript
454 // standard explicitly dictates that historical information should not be considered when
455 // determining DST. For this reason we shift away from years that localtime can handle but would
456 // return historically accurate information.
457 int year = msToYear(ms);
458 int equivalentYear = equivalentYearForDST(year);
459 if (year != equivalentYear) {
460 bool leapYear = isLeapYear(year);
461 int dayInYearLocal = dayInYear(ms, year);
462 int dayInMonth = dayInMonthFromDayInYear(dayInYearLocal, leapYear);
463 int month = monthFromDayInYear(dayInYearLocal, leapYear);
464 double day = dateToDaysFrom1970(equivalentYear, month, dayInMonth);
465 ms = (day * msPerDay) + msToMilliseconds(ms);
466 }
467
468 return calculateDSTOffsetSimple(ms / msPerSecond, utcOffset);
469}
470
471void initializeDates()
472{
473#ifndef NDEBUG
474 static bool alreadyInitialized;
475 ASSERT(!alreadyInitialized);
476 alreadyInitialized = true;
477#endif
478
479 equivalentYearForDST(2000); // Need to call once to initialize a static used in this function.
480}
481
482static inline double ymdhmsToSeconds(long year, int mon, int day, int hour, int minute, int second)
483{
484 double days = (day - 32075)
485 + floor(1461 * (year + 4800.0 + (mon - 14) / 12) / 4)
486 + 367 * (mon - 2 - (mon - 14) / 12 * 12) / 12
487 - floor(3 * ((year + 4900.0 + (mon - 14) / 12) / 100) / 4)
488 - 2440588;
489 return ((days * hoursPerDay + hour) * minutesPerHour + minute) * secondsPerMinute + second;
490}
491
492// We follow the recommendation of RFC 2822 to consider all
493// obsolete time zones not listed here equivalent to "-0000".
494static const struct KnownZone {
495#if !OS(WINDOWS)
496 const
497#endif
498 char tzName[4];
499 int tzOffset;
500} known_zones[] = {
501 { "UT", 0 },
502 { "GMT", 0 },
503 { "EST", -300 },
504 { "EDT", -240 },
505 { "CST", -360 },
506 { "CDT", -300 },
507 { "MST", -420 },
508 { "MDT", -360 },
509 { "PST", -480 },
510 { "PDT", -420 }
511};
512
513inline static void skipSpacesAndComments(const char*& s)
514{
515 int nesting = 0;
516 char ch;
517 while ((ch = *s)) {
518 if (!isASCIISpace(ch)) {
519 if (ch == '(')
520 nesting++;
521 else if (ch == ')' && nesting > 0)
522 nesting--;
523 else if (nesting == 0)
524 break;
525 }
526 s++;
527 }
528}
529
530// returns 0-11 (Jan-Dec); -1 on failure
531static int findMonth(const char* monthStr)
532{
533 ASSERT(monthStr);
534 char needle[4];
535 for (int i = 0; i < 3; ++i) {
536 if (!*monthStr)
537 return -1;
538 needle[i] = static_cast<char>(toASCIILower(*monthStr++));
539 }
540 needle[3] = '\0';
541 const char *haystack = "janfebmaraprmayjunjulaugsepoctnovdec";
542 const char *str = strstr(haystack, needle);
543 if (str) {
544 int position = static_cast<int>(str - haystack);
545 if (position % 3 == 0)
546 return position / 3;
547 }
548 return -1;
549}
550
551static bool parseLong(const char* string, char** stopPosition, int base, long* result)
552{
553 *result = strtol(string, stopPosition, base);
554 // Avoid the use of errno as it is not available on Windows CE
555 if (string == *stopPosition || *result == LONG_MIN || *result == LONG_MAX)
556 return false;
557 return true;
558}
559
560// Odd case where 'exec' is allowed to be 0, to accomodate a caller in WebCore.
561static double parseDateFromNullTerminatedCharacters(const char* dateString, bool& haveTZ, int& offset)
562{
563 haveTZ = false;
564 offset = 0;
565
566 // This parses a date in the form:
567 // Tuesday, 09-Nov-99 23:12:40 GMT
568 // or
569 // Sat, 01-Jan-2000 08:00:00 GMT
570 // or
571 // Sat, 01 Jan 2000 08:00:00 GMT
572 // or
573 // 01 Jan 99 22:00 +0100 (exceptions in rfc822/rfc2822)
574 // ### non RFC formats, added for Javascript:
575 // [Wednesday] January 09 1999 23:12:40 GMT
576 // [Wednesday] January 09 23:12:40 GMT 1999
577 //
578 // We ignore the weekday.
579
580 // Skip leading space
581 skipSpacesAndComments(dateString);
582
583 long month = -1;
584 const char *wordStart = dateString;
585 // Check contents of first words if not number
586 while (*dateString && !isASCIIDigit(*dateString)) {
587 if (isASCIISpace(*dateString) || *dateString == '(') {
588 if (dateString - wordStart >= 3)
589 month = findMonth(wordStart);
590 skipSpacesAndComments(dateString);
591 wordStart = dateString;
592 } else
593 dateString++;
594 }
595
596 // Missing delimiter between month and day (like "January29")?
597 if (month == -1 && wordStart != dateString)
598 month = findMonth(wordStart);
599
600 skipSpacesAndComments(dateString);
601
602 if (!*dateString)
603 return NaN;
604
605 // ' 09-Nov-99 23:12:40 GMT'
606 char* newPosStr;
607 long day;
608 if (!parseLong(dateString, &newPosStr, 10, &day))
609 return NaN;
610 dateString = newPosStr;
611
612 if (!*dateString)
613 return NaN;
614
615 if (day < 0)
616 return NaN;
617
618 long year = 0;
619 if (day > 31) {
620 // ### where is the boundary and what happens below?
621 if (*dateString != '/')
622 return NaN;
623 // looks like a YYYY/MM/DD date
624 if (!*++dateString)
625 return NaN;
626 year = day;
627 if (!parseLong(dateString, &newPosStr, 10, &month))
628 return NaN;
629 month -= 1;
630 dateString = newPosStr;
631 if (*dateString++ != '/' || !*dateString)
632 return NaN;
633 if (!parseLong(dateString, &newPosStr, 10, &day))
634 return NaN;
635 dateString = newPosStr;
636 } else if (*dateString == '/' && month == -1) {
637 dateString++;
638 // This looks like a MM/DD/YYYY date, not an RFC date.
639 month = day - 1; // 0-based
640 if (!parseLong(dateString, &newPosStr, 10, &day))
641 return NaN;
642 if (day < 1 || day > 31)
643 return NaN;
644 dateString = newPosStr;
645 if (*dateString == '/')
646 dateString++;
647 if (!*dateString)
648 return NaN;
649 } else {
650 if (*dateString == '-')
651 dateString++;
652
653 skipSpacesAndComments(dateString);
654
655 if (*dateString == ',')
656 dateString++;
657
658 if (month == -1) { // not found yet
659 month = findMonth(dateString);
660 if (month == -1)
661 return NaN;
662
663 while (*dateString && *dateString != '-' && *dateString != ',' && !isASCIISpace(*dateString))
664 dateString++;
665
666 if (!*dateString)
667 return NaN;
668
669 // '-99 23:12:40 GMT'
670 if (*dateString != '-' && *dateString != '/' && *dateString != ',' && !isASCIISpace(*dateString))
671 return NaN;
672 dateString++;
673 }
674 }
675
676 if (month < 0 || month > 11)
677 return NaN;
678
679 // '99 23:12:40 GMT'
680 if (year <= 0 && *dateString) {
681 if (!parseLong(dateString, &newPosStr, 10, &year))
682 return NaN;
683 }
684
685 // Don't fail if the time is missing.
686 long hour = 0;
687 long minute = 0;
688 long second = 0;
689 if (!*newPosStr)
690 dateString = newPosStr;
691 else {
692 // ' 23:12:40 GMT'
693 if (!(isASCIISpace(*newPosStr) || *newPosStr == ',')) {
694 if (*newPosStr != ':')
695 return NaN;
696 // There was no year; the number was the hour.
697 year = -1;
698 } else {
699 // in the normal case (we parsed the year), advance to the next number
700 dateString = ++newPosStr;
701 skipSpacesAndComments(dateString);
702 }
703
704 parseLong(dateString, &newPosStr, 10, &hour);
705 // Do not check for errno here since we want to continue
706 // even if errno was set becasue we are still looking
707 // for the timezone!
708
709 // Read a number? If not, this might be a timezone name.
710 if (newPosStr != dateString) {
711 dateString = newPosStr;
712
713 if (hour < 0 || hour > 23)
714 return NaN;
715
716 if (!*dateString)
717 return NaN;
718
719 // ':12:40 GMT'
720 if (*dateString++ != ':')
721 return NaN;
722
723 if (!parseLong(dateString, &newPosStr, 10, &minute))
724 return NaN;
725 dateString = newPosStr;
726
727 if (minute < 0 || minute > 59)
728 return NaN;
729
730 // ':40 GMT'
731 if (*dateString && *dateString != ':' && !isASCIISpace(*dateString))
732 return NaN;
733
734 // seconds are optional in rfc822 + rfc2822
735 if (*dateString ==':') {
736 dateString++;
737
738 if (!parseLong(dateString, &newPosStr, 10, &second))
739 return NaN;
740 dateString = newPosStr;
741
742 if (second < 0 || second > 59)
743 return NaN;
744 }
745
746 skipSpacesAndComments(dateString);
747
748 if (strncasecmp(dateString, "AM", 2) == 0) {
749 if (hour > 12)
750 return NaN;
751 if (hour == 12)
752 hour = 0;
753 dateString += 2;
754 skipSpacesAndComments(dateString);
755 } else if (strncasecmp(dateString, "PM", 2) == 0) {
756 if (hour > 12)
757 return NaN;
758 if (hour != 12)
759 hour += 12;
760 dateString += 2;
761 skipSpacesAndComments(dateString);
762 }
763 }
764 }
765
766 // Don't fail if the time zone is missing.
767 // Some websites omit the time zone (4275206).
768 if (*dateString) {
769 if (strncasecmp(dateString, "GMT", 3) == 0 || strncasecmp(dateString, "UTC", 3) == 0) {
770 dateString += 3;
771 haveTZ = true;
772 }
773
774 if (*dateString == '+' || *dateString == '-') {
775 long o;
776 if (!parseLong(dateString, &newPosStr, 10, &o))
777 return NaN;
778 dateString = newPosStr;
779
780 if (o < -9959 || o > 9959)
781 return NaN;
782
783 int sgn = (o < 0) ? -1 : 1;
784 o = labs(o);
785 if (*dateString != ':') {
786 offset = ((o / 100) * 60 + (o % 100)) * sgn;
787 } else { // GMT+05:00
788 long o2;
789 if (!parseLong(dateString, &newPosStr, 10, &o2))
790 return NaN;
791 dateString = newPosStr;
792 offset = (o * 60 + o2) * sgn;
793 }
794 haveTZ = true;
795 } else {
796 for (int i = 0; i < int(sizeof(known_zones) / sizeof(KnownZone)); i++) {
797 if (0 == strncasecmp(dateString, known_zones[i].tzName, strlen(known_zones[i].tzName))) {
798 offset = known_zones[i].tzOffset;
799 dateString += strlen(known_zones[i].tzName);
800 haveTZ = true;
801 break;
802 }
803 }
804 }
805 }
806
807 skipSpacesAndComments(dateString);
808
809 if (*dateString && year == -1) {
810 if (!parseLong(dateString, &newPosStr, 10, &year))
811 return NaN;
812 dateString = newPosStr;
813 }
814
815 skipSpacesAndComments(dateString);
816
817 // Trailing garbage
818 if (*dateString)
819 return NaN;
820
821 // Y2K: Handle 2 digit years.
822 if (year >= 0 && year < 100) {
823 if (year < 50)
824 year += 2000;
825 else
826 year += 1900;
827 }
828
829 return ymdhmsToSeconds(year, month + 1, day, hour, minute, second) * msPerSecond;
830}
831
832double parseDateFromNullTerminatedCharacters(const char* dateString)
833{
834 bool haveTZ;
835 int offset;
836 double ms = parseDateFromNullTerminatedCharacters(dateString, haveTZ, offset);
837 if (isnan(ms))
838 return NaN;
839
840 // fall back to local timezone
841 if (!haveTZ) {
842 double utcOffset = calculateUTCOffset();
843 double dstOffset = calculateDSTOffset(ms, utcOffset);
844 offset = static_cast<int>((utcOffset + dstOffset) / msPerMinute);
845 }
846 return ms - (offset * msPerMinute);
847}
848
849double timeClip(double t)
850{
851 if (!isfinite(t))
852 return NaN;
853 if (fabs(t) > maxECMAScriptTime)
854 return NaN;
855 return trunc(t);
856}
857} // namespace WTF
858
859#if USE(JSC)
860namespace JSC {
861
862// Get the DST offset for the time passed in.
863//
864// NOTE: The implementation relies on the fact that no time zones have
865// more than one daylight savings offset change per month.
866// If this function is called with NaN it returns NaN.
867static double getDSTOffset(ExecState* exec, double ms, double utcOffset)
868{
869 DSTOffsetCache& cache = exec->globalData().dstOffsetCache;
870 double start = cache.start;
871 double end = cache.end;
872
873 if (start <= ms) {
874 // If the time fits in the cached interval, return the cached offset.
875 if (ms <= end) return cache.offset;
876
877 // Compute a possible new interval end.
878 double newEnd = end + cache.increment;
879
880 if (ms <= newEnd) {
881 double endOffset = calculateDSTOffset(newEnd, utcOffset);
882 if (cache.offset == endOffset) {
883 // If the offset at the end of the new interval still matches
884 // the offset in the cache, we grow the cached time interval
885 // and return the offset.
886 cache.end = newEnd;
887 cache.increment = msPerMonth;
888 return endOffset;
889 } else {
890 double offset = calculateDSTOffset(ms, utcOffset);
891 if (offset == endOffset) {
892 // The offset at the given time is equal to the offset at the
893 // new end of the interval, so that means that we've just skipped
894 // the point in time where the DST offset change occurred. Updated
895 // the interval to reflect this and reset the increment.
896 cache.start = ms;
897 cache.end = newEnd;
898 cache.increment = msPerMonth;
899 } else {
900 // The interval contains a DST offset change and the given time is
901 // before it. Adjust the increment to avoid a linear search for
902 // the offset change point and change the end of the interval.
903 cache.increment /= 3;
904 cache.end = ms;
905 }
906 // Update the offset in the cache and return it.
907 cache.offset = offset;
908 return offset;
909 }
910 }
911 }
912
913 // Compute the DST offset for the time and shrink the cache interval
914 // to only contain the time. This allows fast repeated DST offset
915 // computations for the same time.
916 double offset = calculateDSTOffset(ms, utcOffset);
917 cache.offset = offset;
918 cache.start = ms;
919 cache.end = ms;
920 cache.increment = msPerMonth;
921 return offset;
922}
923
924/*
925 * Get the difference in milliseconds between this time zone and UTC (GMT)
926 * NOT including DST.
927 */
928double getUTCOffset(ExecState* exec)
929{
930 double utcOffset = exec->globalData().cachedUTCOffset;
931 if (!isnan(utcOffset))
932 return utcOffset;
933 exec->globalData().cachedUTCOffset = calculateUTCOffset();
934 return exec->globalData().cachedUTCOffset;
935}
936
937double gregorianDateTimeToMS(ExecState* exec, const GregorianDateTime& t, double milliSeconds, bool inputIsUTC)
938{
939 double day = dateToDaysFrom1970(t.year + 1900, t.month, t.monthDay);
940 double ms = timeToMS(t.hour, t.minute, t.second, milliSeconds);
941 double result = (day * WTF::msPerDay) + ms;
942
943 if (!inputIsUTC) { // convert to UTC
944 double utcOffset = getUTCOffset(exec);
945 result -= utcOffset;
946 result -= getDSTOffset(exec, result, utcOffset);
947 }
948
949 return result;
950}
951
952// input is UTC
953void msToGregorianDateTime(ExecState* exec, double ms, bool outputIsUTC, GregorianDateTime& tm)
954{
955 double dstOff = 0.0;
956 double utcOff = 0.0;
957 if (!outputIsUTC) {
958 utcOff = getUTCOffset(exec);
959 dstOff = getDSTOffset(exec, ms, utcOff);
960 ms += dstOff + utcOff;
961 }
962
963 const int year = msToYear(ms);
964 tm.second = msToSeconds(ms);
965 tm.minute = msToMinutes(ms);
966 tm.hour = msToHours(ms);
967 tm.weekDay = msToWeekDay(ms);
968 tm.yearDay = dayInYear(ms, year);
969 tm.monthDay = dayInMonthFromDayInYear(tm.yearDay, isLeapYear(year));
970 tm.month = monthFromDayInYear(tm.yearDay, isLeapYear(year));
971 tm.year = year - 1900;
972 tm.isDST = dstOff != 0.0;
973 tm.utcOffset = static_cast<long>((dstOff + utcOff) / WTF::msPerSecond);
974 tm.timeZone = NULL;
975}
976
977double parseDateFromNullTerminatedCharacters(ExecState* exec, const char* dateString)
978{
979 ASSERT(exec);
980 bool haveTZ;
981 int offset;
982 double ms = WTF::parseDateFromNullTerminatedCharacters(dateString, haveTZ, offset);
983 if (isnan(ms))
984 return NaN;
985
986 // fall back to local timezone
987 if (!haveTZ) {
988 double utcOffset = getUTCOffset(exec);
989 double dstOffset = getDSTOffset(exec, ms, utcOffset);
990 offset = static_cast<int>((utcOffset + dstOffset) / WTF::msPerMinute);
991 }
992 return ms - (offset * WTF::msPerMinute);
993}
994
995} // namespace JSC
996#endif // USE(JSC)
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