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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 #include "MathExtras.h"
79 #include "StdLibExtras.h"
80 #include "StringExtras.h"
81 
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"
89 
90 #if OS(WIN)
91 #include <windows.h>
92 #endif
93 
94 #if HAVE(SYS_TIME_H)
95 #include <sys/time.h>
96 #endif
97 
98 using namespace WTF;
99 
100 namespace WTF {
101 
102 /* Constants */
103 
104 static const double hoursPerDay = 24.0;
105 static const double secondsPerDay = 24.0 * 60.0 * 60.0;
106 
107 static const double maxUnixTime = 2145859200.0; // 12/31/2037
108 
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}
114 };
115 
getLocalTime(const time_t * localTime,struct tm * localTM)116 static inline void getLocalTime(const time_t* localTime, struct tm* localTM)
117 {
118 #if COMPILER(MSVC)
119     localtime_s(localTM, localTime);
120 #else
121     localtime_r(localTime, localTM);
122 #endif
123 }
124 
isLeapYear(int year)125 bool isLeapYear(int year)
126 {
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;
134 }
135 
daysInYear(int year)136 static inline int daysInYear(int year)
137 {
138     return 365 + isLeapYear(year);
139 }
140 
daysFrom1970ToYear(int year)141 static inline double daysFrom1970ToYear(int year)
142 {
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.
147 
148     static const int leapDaysBefore1971By4Rule = 1970 / 4;
149     static const int excludedLeapDaysBefore1971By100Rule = 1970 / 100;
150     static const int leapDaysBefore1971By400Rule = 1970 / 400;
151 
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;
156 
157     return 365.0 * (year - 1970) + yearsToAddBy4Rule - yearsToExcludeBy100Rule + yearsToAddBy400Rule;
158 }
159 
msToDays(double ms)160 static double msToDays(double ms)
161 {
162     return floor(ms / msPerDay);
163 }
164 
appendTwoDigitNumber(StringBuilder & builder,int number)165 static void appendTwoDigitNumber(StringBuilder& builder, int number)
166 {
167     ASSERT(number >= 0 && number < 100);
168     if (number <= 9)
169         builder.append('0');
170     builder.appendNumber(number);
171 }
172 
msToYear(double ms)173 int msToYear(double ms)
174 {
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;
182 }
183 
dayInYear(double ms,int year)184 int dayInYear(double ms, int year)
185 {
186     return static_cast<int>(msToDays(ms) - daysFrom1970ToYear(year));
187 }
188 
msToMilliseconds(double ms)189 static inline double msToMilliseconds(double ms)
190 {
191     double result = fmod(ms, msPerDay);
192     if (result < 0)
193         result += msPerDay;
194     return result;
195 }
196 
monthFromDayInYear(int dayInYear,bool leapYear)197 int monthFromDayInYear(int dayInYear, bool leapYear)
198 {
199     const int d = dayInYear;
200     int step;
201 
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;
226 }
227 
checkMonth(int dayInYear,int & startDayOfThisMonth,int & startDayOfNextMonth,int daysInThisMonth)228 static inline bool checkMonth(int dayInYear, int& startDayOfThisMonth, int& startDayOfNextMonth, int daysInThisMonth)
229 {
230     startDayOfThisMonth = startDayOfNextMonth;
231     startDayOfNextMonth += daysInThisMonth;
232     return (dayInYear <= startDayOfNextMonth);
233 }
234 
dayInMonthFromDayInYear(int dayInYear,bool leapYear)235 int dayInMonthFromDayInYear(int dayInYear, bool leapYear)
236 {
237     const int d = dayInYear;
238     int step;
239     int next = 30;
240 
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;
266 }
267 
dayInYear(int year,int month,int day)268 int dayInYear(int year, int month, int day)
269 {
270     return firstDayOfMonth[isLeapYear(year)][month] + day - 1;
271 }
272 
dateToDaysFrom1970(int year,int month,int day)273 double dateToDaysFrom1970(int year, int month, int day)
274 {
275     year += month / 12;
276 
277     month %= 12;
278     if (month < 0) {
279         month += 12;
280         --year;
281     }
282 
283     double yearday = floor(daysFrom1970ToYear(year));
284     ASSERT((year >= 1970 && yearday >= 0) || (year < 1970 && yearday < 0));
285     return yearday + dayInYear(year, month, day);
286 }
287 
288 // There is a hard limit at 2038 that we currently do not have a workaround
289 // for (rdar://problem/5052975).
maximumYearForDST()290 static inline int maximumYearForDST()
291 {
292     return 2037;
293 }
294 
jsCurrentTime()295 static inline double jsCurrentTime()
296 {
297     // JavaScript doesn't recognize fractions of a millisecond.
298     return floor(WTF::currentTimeMS());
299 }
300 
minimumYearForDST()301 static inline int minimumYearForDST()
302 {
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) ;
308 }
309 
310 /*
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.
314  *
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).
319  */
equivalentYearForDST(int year)320 static int equivalentYearForDST(int year)
321 {
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();
327 
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;
335 
336     int quotient = difference / 28;
337     int product = (quotient) * 28;
338 
339     year += product;
340     ASSERT((year >= minYear && year <= maxYear) || (product - year == static_cast<int>(std::numeric_limits<double>::quiet_NaN())));
341     return year;
342 }
343 
calculateUTCOffset()344 static double calculateUTCOffset()
345 {
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);
355 
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
359 }
360 
361 /*
362  * Get the DST offset for the time passed in.
363  */
calculateDSTOffsetSimple(double localTimeSeconds,double utcOffset)364 static double calculateDSTOffsetSimple(double localTimeSeconds, double utcOffset)
365 {
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;
370 
371     // FIXME: time_t has a potential problem in 2038
372     time_t localTime = static_cast<time_t>(localTimeSeconds);
373 
374     tm localTM;
375     getLocalTime(&localTime, &localTM);
376 
377     return localTM.tm_isdst > 0 ? msPerHour : 0;
378 }
379 
380 // Get the DST offset, given a time in UTC
calculateDSTOffset(double ms,double utcOffset)381 static double calculateDSTOffset(double ms, double utcOffset)
382 {
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);
397     }
398 
399     return calculateDSTOffsetSimple(ms / msPerSecond, utcOffset);
400 }
401 
initializeDates()402 void initializeDates()
403 {
404 #if ENABLE(ASSERT)
405     static bool alreadyInitialized;
406     ASSERT(!alreadyInitialized);
407     alreadyInitialized = true;
408 #endif
409 
410     equivalentYearForDST(2000); // Need to call once to initialize a static used in this function.
411 }
412 
ymdhmsToSeconds(int year,long mon,long day,long hour,long minute,double second)413 static inline double ymdhmsToSeconds(int year, long mon, long day, long hour, long minute, double second)
414 {
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;
421 }
422 
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 }
442 };
443 
skipSpacesAndComments(const char * & s)444 inline static void skipSpacesAndComments(const char*& s)
445 {
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;
456         }
457         s++;
458     }
459 }
460 
461 // returns 0-11 (Jan-Dec); -1 on failure
findMonth(const char * monthStr)462 static int findMonth(const char* monthStr)
463 {
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++));
470     }
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;
478     }
479     return -1;
480 }
481 
parseInt(const char * string,char ** stopPosition,int base,int * result)482 static bool parseInt(const char* string, char** stopPosition, int base, int* result)
483 {
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;
490 }
491 
parseLong(const char * string,char ** stopPosition,int base,long * result)492 static bool parseLong(const char* string, char** stopPosition, int base, long* result)
493 {
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;
499 }
500 
501 // Odd case where 'exec' is allowed to be 0, to accomodate a caller in WebCore.
parseDateFromNullTerminatedCharacters(const char * dateString,bool & haveTZ,int & offset)502 static double parseDateFromNullTerminatedCharacters(const char* dateString, bool& haveTZ, int& offset)
503 {
504     haveTZ = false;
505     offset = 0;
506 
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
518     //
519     // We ignore the weekday.
520 
521     // Skip leading space
522     skipSpacesAndComments(dateString);
523 
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++;
535     }
536 
537     // Missing delimiter between month and day (like "January29")?
538     if (month == -1 && wordStart != dateString)
539         month = findMonth(wordStart);
540 
541     skipSpacesAndComments(dateString);
542 
543     if (!*dateString)
544         return std::numeric_limits<double>::quiet_NaN();
545 
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;
552 
553     if (!*dateString)
554         return std::numeric_limits<double>::quiet_NaN();
555 
556     if (day < 0)
557         return std::numeric_limits<double>::quiet_NaN();
558 
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++;
595 
596         skipSpacesAndComments(dateString);
597 
598         if (*dateString == ',')
599             dateString++;
600 
601         if (month == -1) { // not found yet
602             month = findMonth(dateString);
603             if (month == -1)
604                 return std::numeric_limits<double>::quiet_NaN();
605 
606             while (*dateString && *dateString != '-' && *dateString != ',' && !isASCIISpace(*dateString))
607                 dateString++;
608 
609             if (!*dateString)
610                 return std::numeric_limits<double>::quiet_NaN();
611 
612             // '-99 23:12:40 GMT'
613             if (*dateString != '-' && *dateString != '/' && *dateString != ',' && !isASCIISpace(*dateString))
614                 return std::numeric_limits<double>::quiet_NaN();
615             dateString++;
616         }
617     }
618 
619     if (month < 0 || month > 11)
620         return std::numeric_limits<double>::quiet_NaN();
621 
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();
626     }
627 
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);
645         }
646 
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!
651 
652         // Read a number? If not, this might be a timezone name.
653         if (newPosStr != dateString) {
654             dateString = newPosStr;
655 
656             if (hour < 0 || hour > 23)
657                 return std::numeric_limits<double>::quiet_NaN();
658 
659             if (!*dateString)
660                 return std::numeric_limits<double>::quiet_NaN();
661 
662             // ':12:40 GMT'
663             if (*dateString++ != ':')
664                 return std::numeric_limits<double>::quiet_NaN();
665 
666             if (!parseLong(dateString, &newPosStr, 10, &minute))
667                 return std::numeric_limits<double>::quiet_NaN();
668             dateString = newPosStr;
669 
670             if (minute < 0 || minute > 59)
671                 return std::numeric_limits<double>::quiet_NaN();
672 
673             // ':40 GMT'
674             if (*dateString && *dateString != ':' && !isASCIISpace(*dateString))
675                 return std::numeric_limits<double>::quiet_NaN();
676 
677             // seconds are optional in rfc822 + rfc2822
678             if (*dateString ==':') {
679                 dateString++;
680 
681                 if (!parseLong(dateString, &newPosStr, 10, &second))
682                     return std::numeric_limits<double>::quiet_NaN();
683                 dateString = newPosStr;
684 
685                 if (second < 0 || second > 59)
686                     return std::numeric_limits<double>::quiet_NaN();
687             }
688 
689             skipSpacesAndComments(dateString);
690 
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);
705             }
706         }
707     }
708 
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);
715     }
716 
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;
723         }
724 
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;
730 
731             if (o < -9959 || o > 9959)
732                 return std::numeric_limits<double>::quiet_NaN();
733 
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;
748             }
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;
757                 }
758             }
759         }
760     }
761 
762     skipSpacesAndComments(dateString);
763 
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);
769     }
770 
771     // Trailing garbage
772     if (*dateString)
773         return std::numeric_limits<double>::quiet_NaN();
774 
775     // Y2K: Handle 2 digit years.
776     if (year >= 0 && year < 100) {
777         if (year < 50)
778             year += 2000;
779         else
780             year += 1900;
781     }
782 
783     return ymdhmsToSeconds(year, month + 1, day, hour, minute, second) * msPerSecond;
784 }
785 
parseDateFromNullTerminatedCharacters(const char * dateString)786 double parseDateFromNullTerminatedCharacters(const char* dateString)
787 {
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();
793 
794     // fall back to local timezone
795     if (!haveTZ) {
796         double utcOffset = calculateUTCOffset();
797         double dstOffset = calculateDSTOffset(ms, utcOffset);
798         offset = (utcOffset + dstOffset) / msPerMinute;
799     }
800     return ms - (offset * msPerMinute);
801 }
802 
803 // See http://tools.ietf.org/html/rfc2822#section-3.3 for more information.
makeRFC2822DateString(unsigned dayOfWeek,unsigned day,unsigned month,unsigned year,unsigned hours,unsigned minutes,unsigned seconds,int utcOffset)804 String makeRFC2822DateString(unsigned dayOfWeek, unsigned day, unsigned month, unsigned year, unsigned hours, unsigned minutes, unsigned seconds, int utcOffset)
805 {
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(' ');
815 
816     appendTwoDigitNumber(stringBuilder, hours);
817     stringBuilder.append(':');
818     appendTwoDigitNumber(stringBuilder, minutes);
819     stringBuilder.append(':');
820     appendTwoDigitNumber(stringBuilder, seconds);
821     stringBuilder.append(' ');
822 
823     stringBuilder.append(utcOffset > 0 ? '+' : '-');
824     int absoluteUTCOffset = abs(utcOffset);
825     appendTwoDigitNumber(stringBuilder, absoluteUTCOffset / 60);
826     appendTwoDigitNumber(stringBuilder, absoluteUTCOffset % 60);
827 
828     return stringBuilder.toString();
829 }
830 
convertToLocalTime(double ms)831 double convertToLocalTime(double ms)
832 {
833     double utcOffset = calculateUTCOffset();
834     double dstOffset = calculateDSTOffset(ms, utcOffset);
835     return (ms + utcOffset + dstOffset);
836 }
837 
838 } // namespace WTF
839