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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)
7   *
8   * The Original Code is Mozilla Communicator client code, released
9   * March 31, 1998.
10   *
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.
15   *
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.
20   *
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.
25   *
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
29   *
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.
43  
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:
48   *
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.
58   *
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.
70   */
71  
72  #include "config.h"
73  #include "DateMath.h"
74  
75  #include "Assertions.h"
76  #include "ASCIICType.h"
77  #include "CurrentTime.h"
78  #if USE(JSC)
79  #include "JSObject.h"
80  #endif
81  #include "MathExtras.h"
82  #if USE(JSC)
83  #include "ScopeChain.h"
84  #endif
85  #include "StdLibExtras.h"
86  #include "StringExtras.h"
87  
88  #include <algorithm>
89  #include <limits.h>
90  #include <limits>
91  #include <stdint.h>
92  #include <time.h>
93  
94  
95  #if HAVE(ERRNO_H)
96  #include <errno.h>
97  #endif
98  
99  #if OS(WINCE)
100  extern "C" size_t strftime(char * const s, const size_t maxsize, const char * const format, const struct tm * const t);
101  extern "C" struct tm * localtime(const time_t *timer);
102  #endif
103  
104  #if HAVE(SYS_TIME_H)
105  #include <sys/time.h>
106  #endif
107  
108  #if HAVE(SYS_TIMEB_H)
109  #include <sys/timeb.h>
110  #endif
111  
112  #if USE(JSC)
113  #include "CallFrame.h"
114  #endif
115  
116  #define NaN std::numeric_limits<double>::quiet_NaN()
117  
118  using namespace WTF;
119  
120  namespace WTF {
121  
122  /* Constants */
123  
124  static const double minutesPerDay = 24.0 * 60.0;
125  static const double secondsPerDay = 24.0 * 60.0 * 60.0;
126  static const double secondsPerYear = 24.0 * 60.0 * 60.0 * 365.0;
127  
128  static const double usecPerSec = 1000000.0;
129  
130  static const double maxUnixTime = 2145859200.0; // 12/31/2037
131  // ECMAScript asks not to support for a date of which total
132  // millisecond value is larger than the following value.
133  // See 15.9.1.14 of ECMA-262 5th edition.
134  static const double maxECMAScriptTime = 8.64E15;
135  
136  // Day of year for the first day of each month, where index 0 is January, and day 0 is January 1.
137  // First for non-leap years, then for leap years.
138  static const int firstDayOfMonth[2][12] = {
139      {0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334},
140      {0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335}
141  };
142  
isLeapYear(int year)143  static inline bool isLeapYear(int year)
144  {
145      if (year % 4 != 0)
146          return false;
147      if (year % 400 == 0)
148          return true;
149      if (year % 100 == 0)
150          return false;
151      return true;
152  }
153  
daysInYear(int year)154  static inline int daysInYear(int year)
155  {
156      return 365 + isLeapYear(year);
157  }
158  
daysFrom1970ToYear(int year)159  static inline double daysFrom1970ToYear(int year)
160  {
161      // The Gregorian Calendar rules for leap years:
162      // Every fourth year is a leap year.  2004, 2008, and 2012 are leap years.
163      // However, every hundredth year is not a leap year.  1900 and 2100 are not leap years.
164      // Every four hundred years, there's a leap year after all.  2000 and 2400 are leap years.
165  
166      static const int leapDaysBefore1971By4Rule = 1970 / 4;
167      static const int excludedLeapDaysBefore1971By100Rule = 1970 / 100;
168      static const int leapDaysBefore1971By400Rule = 1970 / 400;
169  
170      const double yearMinusOne = year - 1;
171      const double yearsToAddBy4Rule = floor(yearMinusOne / 4.0) - leapDaysBefore1971By4Rule;
172      const double yearsToExcludeBy100Rule = floor(yearMinusOne / 100.0) - excludedLeapDaysBefore1971By100Rule;
173      const double yearsToAddBy400Rule = floor(yearMinusOne / 400.0) - leapDaysBefore1971By400Rule;
174  
175      return 365.0 * (year - 1970) + yearsToAddBy4Rule - yearsToExcludeBy100Rule + yearsToAddBy400Rule;
176  }
177  
msToDays(double ms)178  static inline double msToDays(double ms)
179  {
180      return floor(ms / msPerDay);
181  }
182  
msToYear(double ms)183  int msToYear(double ms)
184  {
185      int approxYear = static_cast<int>(floor(ms / (msPerDay * 365.2425)) + 1970);
186      double msFromApproxYearTo1970 = msPerDay * daysFrom1970ToYear(approxYear);
187      if (msFromApproxYearTo1970 > ms)
188          return approxYear - 1;
189      if (msFromApproxYearTo1970 + msPerDay * daysInYear(approxYear) <= ms)
190          return approxYear + 1;
191      return approxYear;
192  }
193  
dayInYear(double ms,int year)194  int dayInYear(double ms, int year)
195  {
196      return static_cast<int>(msToDays(ms) - daysFrom1970ToYear(year));
197  }
198  
msToMilliseconds(double ms)199  static inline double msToMilliseconds(double ms)
200  {
201      double result = fmod(ms, msPerDay);
202      if (result < 0)
203          result += msPerDay;
204      return result;
205  }
206  
207  // 0: Sunday, 1: Monday, etc.
msToWeekDay(double ms)208  static inline int msToWeekDay(double ms)
209  {
210      int wd = (static_cast<int>(msToDays(ms)) + 4) % 7;
211      if (wd < 0)
212          wd += 7;
213      return wd;
214  }
215  
msToSeconds(double ms)216  static inline int msToSeconds(double ms)
217  {
218      double result = fmod(floor(ms / msPerSecond), secondsPerMinute);
219      if (result < 0)
220          result += secondsPerMinute;
221      return static_cast<int>(result);
222  }
223  
msToMinutes(double ms)224  static inline int msToMinutes(double ms)
225  {
226      double result = fmod(floor(ms / msPerMinute), minutesPerHour);
227      if (result < 0)
228          result += minutesPerHour;
229      return static_cast<int>(result);
230  }
231  
msToHours(double ms)232  static inline int msToHours(double ms)
233  {
234      double result = fmod(floor(ms/msPerHour), hoursPerDay);
235      if (result < 0)
236          result += hoursPerDay;
237      return static_cast<int>(result);
238  }
239  
monthFromDayInYear(int dayInYear,bool leapYear)240  int monthFromDayInYear(int dayInYear, bool leapYear)
241  {
242      const int d = dayInYear;
243      int step;
244  
245      if (d < (step = 31))
246          return 0;
247      step += (leapYear ? 29 : 28);
248      if (d < step)
249          return 1;
250      if (d < (step += 31))
251          return 2;
252      if (d < (step += 30))
253          return 3;
254      if (d < (step += 31))
255          return 4;
256      if (d < (step += 30))
257          return 5;
258      if (d < (step += 31))
259          return 6;
260      if (d < (step += 31))
261          return 7;
262      if (d < (step += 30))
263          return 8;
264      if (d < (step += 31))
265          return 9;
266      if (d < (step += 30))
267          return 10;
268      return 11;
269  }
270  
checkMonth(int dayInYear,int & startDayOfThisMonth,int & startDayOfNextMonth,int daysInThisMonth)271  static inline bool checkMonth(int dayInYear, int& startDayOfThisMonth, int& startDayOfNextMonth, int daysInThisMonth)
272  {
273      startDayOfThisMonth = startDayOfNextMonth;
274      startDayOfNextMonth += daysInThisMonth;
275      return (dayInYear <= startDayOfNextMonth);
276  }
277  
dayInMonthFromDayInYear(int dayInYear,bool leapYear)278  int dayInMonthFromDayInYear(int dayInYear, bool leapYear)
279  {
280      const int d = dayInYear;
281      int step;
282      int next = 30;
283  
284      if (d <= next)
285          return d + 1;
286      const int daysInFeb = (leapYear ? 29 : 28);
287      if (checkMonth(d, step, next, daysInFeb))
288          return d - step;
289      if (checkMonth(d, step, next, 31))
290          return d - step;
291      if (checkMonth(d, step, next, 30))
292          return d - step;
293      if (checkMonth(d, step, next, 31))
294          return d - step;
295      if (checkMonth(d, step, next, 30))
296          return d - step;
297      if (checkMonth(d, step, next, 31))
298          return d - step;
299      if (checkMonth(d, step, next, 31))
300          return d - step;
301      if (checkMonth(d, step, next, 30))
302          return d - step;
303      if (checkMonth(d, step, next, 31))
304          return d - step;
305      if (checkMonth(d, step, next, 30))
306          return d - step;
307      step = next;
308      return d - step;
309  }
310  
monthToDayInYear(int month,bool isLeapYear)311  static inline int monthToDayInYear(int month, bool isLeapYear)
312  {
313      return firstDayOfMonth[isLeapYear][month];
314  }
315  
timeToMS(double hour,double min,double sec,double ms)316  static inline double timeToMS(double hour, double min, double sec, double ms)
317  {
318      return (((hour * minutesPerHour + min) * secondsPerMinute + sec) * msPerSecond + ms);
319  }
320  
dateToDaysFrom1970(int year,int month,int day)321  double dateToDaysFrom1970(int year, int month, int day)
322  {
323      year += month / 12;
324  
325      month %= 12;
326      if (month < 0) {
327          month += 12;
328          --year;
329      }
330  
331      double yearday = floor(daysFrom1970ToYear(year));
332      ASSERT((year >= 1970 && yearday >= 0) || (year < 1970 && yearday < 0));
333      int monthday = monthToDayInYear(month, isLeapYear(year));
334  
335      return yearday + monthday + day - 1;
336  }
337  
338  // There is a hard limit at 2038 that we currently do not have a workaround
339  // for (rdar://problem/5052975).
maximumYearForDST()340  static inline int maximumYearForDST()
341  {
342      return 2037;
343  }
344  
minimumYearForDST()345  static inline int minimumYearForDST()
346  {
347      // Because of the 2038 issue (see maximumYearForDST) if the current year is
348      // greater than the max year minus 27 (2010), we want to use the max year
349      // minus 27 instead, to ensure there is a range of 28 years that all years
350      // can map to.
351      return std::min(msToYear(jsCurrentTime()), maximumYearForDST() - 27) ;
352  }
353  
354  /*
355   * Find an equivalent year for the one given, where equivalence is deterined by
356   * the two years having the same leapness and the first day of the year, falling
357   * on the same day of the week.
358   *
359   * This function returns a year between this current year and 2037, however this
360   * function will potentially return incorrect results if the current year is after
361   * 2010, (rdar://problem/5052975), if the year passed in is before 1900 or after
362   * 2100, (rdar://problem/5055038).
363   */
equivalentYearForDST(int year)364  int equivalentYearForDST(int year)
365  {
366      // It is ok if the cached year is not the current year as long as the rules
367      // for DST did not change between the two years; if they did the app would need
368      // to be restarted.
369      static int minYear = minimumYearForDST();
370      int maxYear = maximumYearForDST();
371  
372      int difference;
373      if (year > maxYear)
374          difference = minYear - year;
375      else if (year < minYear)
376          difference = maxYear - year;
377      else
378          return year;
379  
380      int quotient = difference / 28;
381      int product = (quotient) * 28;
382  
383      year += product;
384      ASSERT((year >= minYear && year <= maxYear) || (product - year == static_cast<int>(NaN)));
385      return year;
386  }
387  
calculateUTCOffset()388  int32_t calculateUTCOffset()
389  {
390  #if PLATFORM(BREWMP)
391      time_t localTime = static_cast<time_t>(currentTime());
392  #else
393      time_t localTime = time(0);
394  #endif
395      tm localt;
396      getLocalTime(&localTime, &localt);
397  
398      // Get the difference between this time zone and UTC on the 1st of January of this year.
399      localt.tm_sec = 0;
400      localt.tm_min = 0;
401      localt.tm_hour = 0;
402      localt.tm_mday = 1;
403      localt.tm_mon = 0;
404      // Not setting localt.tm_year!
405      localt.tm_wday = 0;
406      localt.tm_yday = 0;
407      localt.tm_isdst = 0;
408  #if HAVE(TM_GMTOFF)
409      localt.tm_gmtoff = 0;
410  #endif
411  #if HAVE(TM_ZONE)
412      localt.tm_zone = 0;
413  #endif
414  
415  #if HAVE(TIMEGM)
416      time_t utcOffset = timegm(&localt) - mktime(&localt);
417  #else
418      // Using a canned date of 01/01/2009 on platforms with weaker date-handling foo.
419      localt.tm_year = 109;
420      time_t utcOffset = 1230768000 - mktime(&localt);
421  #endif
422  
423      return static_cast<int32_t>(utcOffset * 1000);
424  }
425  
426  /*
427   * Get the DST offset for the time passed in.
428   */
calculateDSTOffsetSimple(double localTimeSeconds,double utcOffset)429  static double calculateDSTOffsetSimple(double localTimeSeconds, double utcOffset)
430  {
431      if (localTimeSeconds > maxUnixTime)
432          localTimeSeconds = maxUnixTime;
433      else if (localTimeSeconds < 0) // Go ahead a day to make localtime work (does not work with 0)
434          localTimeSeconds += secondsPerDay;
435  
436      //input is UTC so we have to shift back to local time to determine DST thus the + getUTCOffset()
437      double offsetTime = (localTimeSeconds * msPerSecond) + utcOffset;
438  
439      // Offset from UTC but doesn't include DST obviously
440      int offsetHour =  msToHours(offsetTime);
441      int offsetMinute =  msToMinutes(offsetTime);
442  
443      // FIXME: time_t has a potential problem in 2038
444      time_t localTime = static_cast<time_t>(localTimeSeconds);
445  
446      tm localTM;
447      getLocalTime(&localTime, &localTM);
448  
449      double diff = ((localTM.tm_hour - offsetHour) * secondsPerHour) + ((localTM.tm_min - offsetMinute) * 60);
450  
451      if (diff < 0)
452          diff += secondsPerDay;
453  
454      return (diff * msPerSecond);
455  }
456  
457  // Get the DST offset, given a time in UTC
calculateDSTOffset(double ms,double utcOffset)458  double calculateDSTOffset(double ms, double utcOffset)
459  {
460      // On Mac OS X, the call to localtime (see calculateDSTOffsetSimple) will return historically accurate
461      // DST information (e.g. New Zealand did not have DST from 1946 to 1974) however the JavaScript
462      // standard explicitly dictates that historical information should not be considered when
463      // determining DST. For this reason we shift away from years that localtime can handle but would
464      // return historically accurate information.
465      int year = msToYear(ms);
466      int equivalentYear = equivalentYearForDST(year);
467      if (year != equivalentYear) {
468          bool leapYear = isLeapYear(year);
469          int dayInYearLocal = dayInYear(ms, year);
470          int dayInMonth = dayInMonthFromDayInYear(dayInYearLocal, leapYear);
471          int month = monthFromDayInYear(dayInYearLocal, leapYear);
472          double day = dateToDaysFrom1970(equivalentYear, month, dayInMonth);
473          ms = (day * msPerDay) + msToMilliseconds(ms);
474      }
475  
476      return calculateDSTOffsetSimple(ms / msPerSecond, utcOffset);
477  }
478  
initializeDates()479  void initializeDates()
480  {
481  #ifndef NDEBUG
482      static bool alreadyInitialized;
483      ASSERT(!alreadyInitialized);
484      alreadyInitialized = true;
485  #endif
486  
487      equivalentYearForDST(2000); // Need to call once to initialize a static used in this function.
488  }
489  
ymdhmsToSeconds(long year,int mon,int day,int hour,int minute,double second)490  static inline double ymdhmsToSeconds(long year, int mon, int day, int hour, int minute, double second)
491  {
492      double days = (day - 32075)
493          + floor(1461 * (year + 4800.0 + (mon - 14) / 12) / 4)
494          + 367 * (mon - 2 - (mon - 14) / 12 * 12) / 12
495          - floor(3 * ((year + 4900.0 + (mon - 14) / 12) / 100) / 4)
496          - 2440588;
497      return ((days * hoursPerDay + hour) * minutesPerHour + minute) * secondsPerMinute + second;
498  }
499  
500  // We follow the recommendation of RFC 2822 to consider all
501  // obsolete time zones not listed here equivalent to "-0000".
502  static const struct KnownZone {
503  #if !OS(WINDOWS)
504      const
505  #endif
506          char tzName[4];
507      int tzOffset;
508  } known_zones[] = {
509      { "UT", 0 },
510      { "GMT", 0 },
511      { "EST", -300 },
512      { "EDT", -240 },
513      { "CST", -360 },
514      { "CDT", -300 },
515      { "MST", -420 },
516      { "MDT", -360 },
517      { "PST", -480 },
518      { "PDT", -420 }
519  };
520  
skipSpacesAndComments(const char * & s)521  inline static void skipSpacesAndComments(const char*& s)
522  {
523      int nesting = 0;
524      char ch;
525      while ((ch = *s)) {
526          if (!isASCIISpace(ch)) {
527              if (ch == '(')
528                  nesting++;
529              else if (ch == ')' && nesting > 0)
530                  nesting--;
531              else if (nesting == 0)
532                  break;
533          }
534          s++;
535      }
536  }
537  
538  // returns 0-11 (Jan-Dec); -1 on failure
findMonth(const char * monthStr)539  static int findMonth(const char* monthStr)
540  {
541      ASSERT(monthStr);
542      char needle[4];
543      for (int i = 0; i < 3; ++i) {
544          if (!*monthStr)
545              return -1;
546          needle[i] = static_cast<char>(toASCIILower(*monthStr++));
547      }
548      needle[3] = '\0';
549      const char *haystack = "janfebmaraprmayjunjulaugsepoctnovdec";
550      const char *str = strstr(haystack, needle);
551      if (str) {
552          int position = static_cast<int>(str - haystack);
553          if (position % 3 == 0)
554              return position / 3;
555      }
556      return -1;
557  }
558  
parseLong(const char * string,char ** stopPosition,int base,long * result)559  static bool parseLong(const char* string, char** stopPosition, int base, long* result)
560  {
561      *result = strtol(string, stopPosition, base);
562      // Avoid the use of errno as it is not available on Windows CE
563      if (string == *stopPosition || *result == LONG_MIN || *result == LONG_MAX)
564          return false;
565      return true;
566  }
567  
parseES5DateFromNullTerminatedCharacters(const char * dateString)568  double parseES5DateFromNullTerminatedCharacters(const char* dateString)
569  {
570      // This parses a date of the form defined in ECMA-262-5, section 15.9.1.15
571      // (similar to RFC 3339 / ISO 8601: YYYY-MM-DDTHH:mm:ss[.sss]Z).
572      // In most cases it is intentionally strict (e.g. correct field widths, no stray whitespace).
573  
574      static const long daysPerMonth[12] = { 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
575  
576      const char* currentPosition = dateString;
577      char* postParsePosition;
578  
579      // This is a bit more lenient on the year string than ES5 specifies:
580      // instead of restricting to 4 digits (or 6 digits with mandatory +/-),
581      // it accepts any integer value. Consider this an implementation fallback.
582      long year;
583      if (!parseLong(currentPosition, &postParsePosition, 10, &year))
584          return NaN;
585      if (*postParsePosition != '-')
586          return NaN;
587      currentPosition = postParsePosition + 1;
588  
589      long month;
590      if (!isASCIIDigit(*currentPosition))
591          return NaN;
592      if (!parseLong(currentPosition, &postParsePosition, 10, &month))
593          return NaN;
594      if (*postParsePosition != '-' || (postParsePosition - currentPosition) != 2)
595          return NaN;
596      currentPosition = postParsePosition + 1;
597  
598      long day;
599      if (!isASCIIDigit(*currentPosition))
600          return NaN;
601      if (!parseLong(currentPosition, &postParsePosition, 10, &day))
602          return NaN;
603      if (*postParsePosition != 'T' || (postParsePosition - currentPosition) != 2)
604          return NaN;
605      currentPosition = postParsePosition + 1;
606  
607      long hours;
608      if (!isASCIIDigit(*currentPosition))
609          return NaN;
610      if (!parseLong(currentPosition, &postParsePosition, 10, &hours))
611          return NaN;
612      if (*postParsePosition != ':' || (postParsePosition - currentPosition) != 2)
613          return NaN;
614      currentPosition = postParsePosition + 1;
615  
616      long minutes;
617      if (!isASCIIDigit(*currentPosition))
618          return NaN;
619      if (!parseLong(currentPosition, &postParsePosition, 10, &minutes))
620          return NaN;
621      if (*postParsePosition != ':' || (postParsePosition - currentPosition) != 2)
622          return NaN;
623      currentPosition = postParsePosition + 1;
624  
625      long intSeconds;
626      if (!isASCIIDigit(*currentPosition))
627          return NaN;
628      if (!parseLong(currentPosition, &postParsePosition, 10, &intSeconds))
629          return NaN;
630      if ((postParsePosition - currentPosition) != 2)
631          return NaN;
632  
633      double seconds = intSeconds;
634      if (*postParsePosition == '.') {
635          currentPosition = postParsePosition + 1;
636  
637          // In ECMA-262-5 it's a bit unclear if '.' can be present without milliseconds, but
638          // a reasonable interpretation guided by the given examples and RFC 3339 says "no".
639          // We check the next character to avoid reading +/- timezone hours after an invalid decimal.
640          if (!isASCIIDigit(*currentPosition))
641              return NaN;
642  
643          // We are more lenient than ES5 by accepting more or less than 3 fraction digits.
644          long fracSeconds;
645          if (!parseLong(currentPosition, &postParsePosition, 10, &fracSeconds))
646              return NaN;
647  
648          long numFracDigits = postParsePosition - currentPosition;
649          seconds += fracSeconds * pow(10.0, static_cast<double>(-numFracDigits));
650      }
651      currentPosition = postParsePosition;
652  
653      // A few of these checks could be done inline above, but since many of them are interrelated
654      // we would be sacrificing readability to "optimize" the (presumably less common) failure path.
655      if (month < 1 || month > 12)
656          return NaN;
657      if (day < 1 || day > daysPerMonth[month - 1])
658          return NaN;
659      if (month == 2 && day > 28 && !isLeapYear(year))
660          return NaN;
661      if (hours < 0 || hours > 24)
662          return NaN;
663      if (hours == 24 && (minutes || seconds))
664          return NaN;
665      if (minutes < 0 || minutes > 59)
666          return NaN;
667      if (seconds < 0 || seconds >= 61)
668          return NaN;
669      if (seconds > 60) {
670          // Discard leap seconds by clamping to the end of a minute.
671          seconds = 60;
672      }
673  
674      long timeZoneSeconds = 0;
675      if (*currentPosition != 'Z') {
676          bool tzNegative;
677          if (*currentPosition == '-')
678              tzNegative = true;
679          else if (*currentPosition == '+')
680              tzNegative = false;
681          else
682              return NaN;
683          currentPosition += 1;
684  
685          long tzHours;
686          long tzHoursAbs;
687          long tzMinutes;
688  
689          if (!isASCIIDigit(*currentPosition))
690              return NaN;
691          if (!parseLong(currentPosition, &postParsePosition, 10, &tzHours))
692              return NaN;
693          if (*postParsePosition != ':' || (postParsePosition - currentPosition) != 2)
694              return NaN;
695          tzHoursAbs = abs(tzHours);
696          currentPosition = postParsePosition + 1;
697  
698          if (!isASCIIDigit(*currentPosition))
699              return NaN;
700          if (!parseLong(currentPosition, &postParsePosition, 10, &tzMinutes))
701              return NaN;
702          if ((postParsePosition - currentPosition) != 2)
703              return NaN;
704          currentPosition = postParsePosition;
705  
706          if (tzHoursAbs > 24)
707              return NaN;
708          if (tzMinutes < 0 || tzMinutes > 59)
709              return NaN;
710  
711          timeZoneSeconds = 60 * (tzMinutes + (60 * tzHoursAbs));
712          if (tzNegative)
713              timeZoneSeconds = -timeZoneSeconds;
714      } else {
715          currentPosition += 1;
716      }
717      if (*currentPosition)
718          return NaN;
719  
720      double dateSeconds = ymdhmsToSeconds(year, month, day, hours, minutes, seconds) - timeZoneSeconds;
721      return dateSeconds * msPerSecond;
722  }
723  
724  // Odd case where 'exec' is allowed to be 0, to accomodate a caller in WebCore.
parseDateFromNullTerminatedCharacters(const char * dateString,bool & haveTZ,int & offset)725  static double parseDateFromNullTerminatedCharacters(const char* dateString, bool& haveTZ, int& offset)
726  {
727      haveTZ = false;
728      offset = 0;
729  
730      // This parses a date in the form:
731      //     Tuesday, 09-Nov-99 23:12:40 GMT
732      // or
733      //     Sat, 01-Jan-2000 08:00:00 GMT
734      // or
735      //     Sat, 01 Jan 2000 08:00:00 GMT
736      // or
737      //     01 Jan 99 22:00 +0100    (exceptions in rfc822/rfc2822)
738      // ### non RFC formats, added for Javascript:
739      //     [Wednesday] January 09 1999 23:12:40 GMT
740      //     [Wednesday] January 09 23:12:40 GMT 1999
741      //
742      // We ignore the weekday.
743  
744      // Skip leading space
745      skipSpacesAndComments(dateString);
746  
747      long month = -1;
748      const char *wordStart = dateString;
749      // Check contents of first words if not number
750      while (*dateString && !isASCIIDigit(*dateString)) {
751          if (isASCIISpace(*dateString) || *dateString == '(') {
752              if (dateString - wordStart >= 3)
753                  month = findMonth(wordStart);
754              skipSpacesAndComments(dateString);
755              wordStart = dateString;
756          } else
757             dateString++;
758      }
759  
760      // Missing delimiter between month and day (like "January29")?
761      if (month == -1 && wordStart != dateString)
762          month = findMonth(wordStart);
763  
764      skipSpacesAndComments(dateString);
765  
766      if (!*dateString)
767          return NaN;
768  
769      // ' 09-Nov-99 23:12:40 GMT'
770      char* newPosStr;
771      long day;
772      if (!parseLong(dateString, &newPosStr, 10, &day))
773          return NaN;
774      dateString = newPosStr;
775  
776      if (!*dateString)
777          return NaN;
778  
779      if (day < 0)
780          return NaN;
781  
782      long year = 0;
783      if (day > 31) {
784          // ### where is the boundary and what happens below?
785          if (*dateString != '/')
786              return NaN;
787          // looks like a YYYY/MM/DD date
788          if (!*++dateString)
789              return NaN;
790          year = day;
791          if (!parseLong(dateString, &newPosStr, 10, &month))
792              return NaN;
793          month -= 1;
794          dateString = newPosStr;
795          if (*dateString++ != '/' || !*dateString)
796              return NaN;
797          if (!parseLong(dateString, &newPosStr, 10, &day))
798              return NaN;
799          dateString = newPosStr;
800      } else if (*dateString == '/' && month == -1) {
801          dateString++;
802          // This looks like a MM/DD/YYYY date, not an RFC date.
803          month = day - 1; // 0-based
804          if (!parseLong(dateString, &newPosStr, 10, &day))
805              return NaN;
806          if (day < 1 || day > 31)
807              return NaN;
808          dateString = newPosStr;
809          if (*dateString == '/')
810              dateString++;
811          if (!*dateString)
812              return NaN;
813       } else {
814          if (*dateString == '-')
815              dateString++;
816  
817          skipSpacesAndComments(dateString);
818  
819          if (*dateString == ',')
820              dateString++;
821  
822          if (month == -1) { // not found yet
823              month = findMonth(dateString);
824              if (month == -1)
825                  return NaN;
826  
827              while (*dateString && *dateString != '-' && *dateString != ',' && !isASCIISpace(*dateString))
828                  dateString++;
829  
830              if (!*dateString)
831                  return NaN;
832  
833              // '-99 23:12:40 GMT'
834              if (*dateString != '-' && *dateString != '/' && *dateString != ',' && !isASCIISpace(*dateString))
835                  return NaN;
836              dateString++;
837          }
838      }
839  
840      if (month < 0 || month > 11)
841          return NaN;
842  
843      // '99 23:12:40 GMT'
844      if (year <= 0 && *dateString) {
845          if (!parseLong(dateString, &newPosStr, 10, &year))
846              return NaN;
847      }
848  
849      // Don't fail if the time is missing.
850      long hour = 0;
851      long minute = 0;
852      long second = 0;
853      if (!*newPosStr)
854          dateString = newPosStr;
855      else {
856          // ' 23:12:40 GMT'
857          if (!(isASCIISpace(*newPosStr) || *newPosStr == ',')) {
858              if (*newPosStr != ':')
859                  return NaN;
860              // There was no year; the number was the hour.
861              year = -1;
862          } else {
863              // in the normal case (we parsed the year), advance to the next number
864              dateString = ++newPosStr;
865              skipSpacesAndComments(dateString);
866          }
867  
868          parseLong(dateString, &newPosStr, 10, &hour);
869          // Do not check for errno here since we want to continue
870          // even if errno was set becasue we are still looking
871          // for the timezone!
872  
873          // Read a number? If not, this might be a timezone name.
874          if (newPosStr != dateString) {
875              dateString = newPosStr;
876  
877              if (hour < 0 || hour > 23)
878                  return NaN;
879  
880              if (!*dateString)
881                  return NaN;
882  
883              // ':12:40 GMT'
884              if (*dateString++ != ':')
885                  return NaN;
886  
887              if (!parseLong(dateString, &newPosStr, 10, &minute))
888                  return NaN;
889              dateString = newPosStr;
890  
891              if (minute < 0 || minute > 59)
892                  return NaN;
893  
894              // ':40 GMT'
895              if (*dateString && *dateString != ':' && !isASCIISpace(*dateString))
896                  return NaN;
897  
898              // seconds are optional in rfc822 + rfc2822
899              if (*dateString ==':') {
900                  dateString++;
901  
902                  if (!parseLong(dateString, &newPosStr, 10, &second))
903                      return NaN;
904                  dateString = newPosStr;
905  
906                  if (second < 0 || second > 59)
907                      return NaN;
908              }
909  
910              skipSpacesAndComments(dateString);
911  
912              if (strncasecmp(dateString, "AM", 2) == 0) {
913                  if (hour > 12)
914                      return NaN;
915                  if (hour == 12)
916                      hour = 0;
917                  dateString += 2;
918                  skipSpacesAndComments(dateString);
919              } else if (strncasecmp(dateString, "PM", 2) == 0) {
920                  if (hour > 12)
921                      return NaN;
922                  if (hour != 12)
923                      hour += 12;
924                  dateString += 2;
925                  skipSpacesAndComments(dateString);
926              }
927          }
928      }
929  
930      // The year may be after the time but before the time zone, but don't
931      // confuse a time zone specificed as an offset from UTC (e.g. +0100) with a
932      // four-digit year.
933      if (year <= 0 && *dateString != '+' && *dateString != '-') {
934         if (!parseLong(dateString, &newPosStr, 10, &year))
935            year = 0;
936         dateString = newPosStr;
937         skipSpacesAndComments(dateString);
938      }
939  
940      // Don't fail if the time zone is missing.
941      // Some websites omit the time zone (4275206).
942      if (*dateString) {
943          if (strncasecmp(dateString, "GMT", 3) == 0 || strncasecmp(dateString, "UTC", 3) == 0) {
944              dateString += 3;
945              haveTZ = true;
946          }
947  
948          if (*dateString == '+' || *dateString == '-') {
949              long o;
950              if (!parseLong(dateString, &newPosStr, 10, &o))
951                  return NaN;
952              dateString = newPosStr;
953  
954              if (o < -9959 || o > 9959)
955                  return NaN;
956  
957              int sgn = (o < 0) ? -1 : 1;
958              o = labs(o);
959              if (*dateString != ':') {
960                  offset = ((o / 100) * 60 + (o % 100)) * sgn;
961              } else { // GMT+05:00
962                  long o2;
963                  if (!parseLong(dateString, &newPosStr, 10, &o2))
964                      return NaN;
965                  dateString = newPosStr;
966                  offset = (o * 60 + o2) * sgn;
967              }
968              haveTZ = true;
969          } else {
970              for (size_t i = 0; i < WTF_ARRAY_LENGTH(known_zones); ++i) {
971                  if (0 == strncasecmp(dateString, known_zones[i].tzName, strlen(known_zones[i].tzName))) {
972                      offset = known_zones[i].tzOffset;
973                      dateString += strlen(known_zones[i].tzName);
974                      haveTZ = true;
975                      break;
976                  }
977              }
978          }
979      }
980  
981      skipSpacesAndComments(dateString);
982  
983      if (*dateString && year == -1) {
984          if (!parseLong(dateString, &newPosStr, 10, &year))
985              return NaN;
986          dateString = newPosStr;
987      }
988  
989      skipSpacesAndComments(dateString);
990  
991      // Trailing garbage
992      if (*dateString)
993          return NaN;
994  
995      // Y2K: Handle 2 digit years.
996      if (year >= 0 && year < 100) {
997          if (year < 50)
998              year += 2000;
999          else
1000              year += 1900;
1001      }
1002  
1003      return ymdhmsToSeconds(year, month + 1, day, hour, minute, second) * msPerSecond;
1004  }
1005  
parseDateFromNullTerminatedCharacters(const char * dateString)1006  double parseDateFromNullTerminatedCharacters(const char* dateString)
1007  {
1008      bool haveTZ;
1009      int offset;
1010      double ms = parseDateFromNullTerminatedCharacters(dateString, haveTZ, offset);
1011      if (isnan(ms))
1012          return NaN;
1013  
1014      // fall back to local timezone
1015      if (!haveTZ) {
1016          double utcOffset = calculateUTCOffset();
1017          double dstOffset = calculateDSTOffset(ms, utcOffset);
1018          offset = static_cast<int>((utcOffset + dstOffset) / msPerMinute);
1019      }
1020      return ms - (offset * msPerMinute);
1021  }
1022  
timeClip(double t)1023  double timeClip(double t)
1024  {
1025      if (!isfinite(t))
1026          return NaN;
1027      if (fabs(t) > maxECMAScriptTime)
1028          return NaN;
1029      return trunc(t);
1030  }
1031  } // namespace WTF
1032  
1033  #if USE(JSC)
1034  namespace JSC {
1035  
1036  // Get the DST offset for the time passed in.
1037  //
1038  // NOTE: The implementation relies on the fact that no time zones have
1039  // more than one daylight savings offset change per month.
1040  // If this function is called with NaN it returns NaN.
getDSTOffset(ExecState * exec,double ms,double utcOffset)1041  static double getDSTOffset(ExecState* exec, double ms, double utcOffset)
1042  {
1043      DSTOffsetCache& cache = exec->globalData().dstOffsetCache;
1044      double start = cache.start;
1045      double end = cache.end;
1046  
1047      if (start <= ms) {
1048          // If the time fits in the cached interval, return the cached offset.
1049          if (ms <= end) return cache.offset;
1050  
1051          // Compute a possible new interval end.
1052          double newEnd = end + cache.increment;
1053  
1054          if (ms <= newEnd) {
1055              double endOffset = calculateDSTOffset(newEnd, utcOffset);
1056              if (cache.offset == endOffset) {
1057                  // If the offset at the end of the new interval still matches
1058                  // the offset in the cache, we grow the cached time interval
1059                  // and return the offset.
1060                  cache.end = newEnd;
1061                  cache.increment = msPerMonth;
1062                  return endOffset;
1063              } else {
1064                  double offset = calculateDSTOffset(ms, utcOffset);
1065                  if (offset == endOffset) {
1066                      // The offset at the given time is equal to the offset at the
1067                      // new end of the interval, so that means that we've just skipped
1068                      // the point in time where the DST offset change occurred. Updated
1069                      // the interval to reflect this and reset the increment.
1070                      cache.start = ms;
1071                      cache.end = newEnd;
1072                      cache.increment = msPerMonth;
1073                  } else {
1074                      // The interval contains a DST offset change and the given time is
1075                      // before it. Adjust the increment to avoid a linear search for
1076                      // the offset change point and change the end of the interval.
1077                      cache.increment /= 3;
1078                      cache.end = ms;
1079                  }
1080                  // Update the offset in the cache and return it.
1081                  cache.offset = offset;
1082                  return offset;
1083              }
1084          }
1085      }
1086  
1087      // Compute the DST offset for the time and shrink the cache interval
1088      // to only contain the time. This allows fast repeated DST offset
1089      // computations for the same time.
1090      double offset = calculateDSTOffset(ms, utcOffset);
1091      cache.offset = offset;
1092      cache.start = ms;
1093      cache.end = ms;
1094      cache.increment = msPerMonth;
1095      return offset;
1096  }
1097  
1098  /*
1099   * Get the difference in milliseconds between this time zone and UTC (GMT)
1100   * NOT including DST.
1101   */
getUTCOffset(ExecState * exec)1102  double getUTCOffset(ExecState* exec)
1103  {
1104      double utcOffset = exec->globalData().cachedUTCOffset;
1105      if (!isnan(utcOffset))
1106          return utcOffset;
1107      exec->globalData().cachedUTCOffset = calculateUTCOffset();
1108      return exec->globalData().cachedUTCOffset;
1109  }
1110  
gregorianDateTimeToMS(ExecState * exec,const GregorianDateTime & t,double milliSeconds,bool inputIsUTC)1111  double gregorianDateTimeToMS(ExecState* exec, const GregorianDateTime& t, double milliSeconds, bool inputIsUTC)
1112  {
1113      double day = dateToDaysFrom1970(t.year + 1900, t.month, t.monthDay);
1114      double ms = timeToMS(t.hour, t.minute, t.second, milliSeconds);
1115      double result = (day * WTF::msPerDay) + ms;
1116  
1117      if (!inputIsUTC) { // convert to UTC
1118          double utcOffset = getUTCOffset(exec);
1119          result -= utcOffset;
1120          result -= getDSTOffset(exec, result, utcOffset);
1121      }
1122  
1123      return result;
1124  }
1125  
1126  // input is UTC
msToGregorianDateTime(ExecState * exec,double ms,bool outputIsUTC,GregorianDateTime & tm)1127  void msToGregorianDateTime(ExecState* exec, double ms, bool outputIsUTC, GregorianDateTime& tm)
1128  {
1129      double dstOff = 0.0;
1130      double utcOff = 0.0;
1131      if (!outputIsUTC) {
1132          utcOff = getUTCOffset(exec);
1133          dstOff = getDSTOffset(exec, ms, utcOff);
1134          ms += dstOff + utcOff;
1135      }
1136  
1137      const int year = msToYear(ms);
1138      tm.second   =  msToSeconds(ms);
1139      tm.minute   =  msToMinutes(ms);
1140      tm.hour     =  msToHours(ms);
1141      tm.weekDay  =  msToWeekDay(ms);
1142      tm.yearDay  =  dayInYear(ms, year);
1143      tm.monthDay =  dayInMonthFromDayInYear(tm.yearDay, isLeapYear(year));
1144      tm.month    =  monthFromDayInYear(tm.yearDay, isLeapYear(year));
1145      tm.year     =  year - 1900;
1146      tm.isDST    =  dstOff != 0.0;
1147      tm.utcOffset = static_cast<long>((dstOff + utcOff) / WTF::msPerSecond);
1148      tm.timeZone = nullptr;
1149  }
1150  
parseDateFromNullTerminatedCharacters(ExecState * exec,const char * dateString)1151  double parseDateFromNullTerminatedCharacters(ExecState* exec, const char* dateString)
1152  {
1153      ASSERT(exec);
1154      bool haveTZ;
1155      int offset;
1156      double ms = WTF::parseDateFromNullTerminatedCharacters(dateString, haveTZ, offset);
1157      if (isnan(ms))
1158          return NaN;
1159  
1160      // fall back to local timezone
1161      if (!haveTZ) {
1162          double utcOffset = getUTCOffset(exec);
1163          double dstOffset = getDSTOffset(exec, ms, utcOffset);
1164          offset = static_cast<int>((utcOffset + dstOffset) / WTF::msPerMinute);
1165      }
1166      return ms - (offset * WTF::msPerMinute);
1167  }
1168  
1169  } // namespace JSC
1170  #endif // USE(JSC)
1171