xref: /aosp_15_r20/external/cronet/base/third_party/nspr/prtime.cc (revision 6777b5387eb2ff775bb5750e3f5d96f37fb7352b)
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3  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
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14  *
15  * The Original Code is the Netscape Portable Runtime (NSPR).
16  *
17  * The Initial Developer of the Original Code is
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37 
38 /*
39  * prtime.cc --
40  * NOTE: The original nspr file name is prtime.c
41  *
42  *     NSPR date and time functions
43  *
44  * CVS revision 3.37
45  */
46 
47 /*
48  * The following functions were copied from the NSPR prtime.c file.
49  * PR_ParseTimeString
50  *   We inlined the new PR_ParseTimeStringToExplodedTime function to avoid
51  *   copying PR_ExplodeTime and PR_LocalTimeParameters.  (The PR_ExplodeTime
52  *   and PR_ImplodeTime calls cancel each other out.)
53  * PR_NormalizeTime
54  * PR_GMTParameters
55  * PR_ImplodeTime
56  *   Upstream implementation from
57  *   http://lxr.mozilla.org/nspr/source/pr/src/misc/prtime.c#221
58  * All types and macros are defined in the base/third_party/prtime.h file.
59  * These have been copied from the following nspr files. We have only copied
60  * over the types we need.
61  * 1. prtime.h
62  * 2. prtypes.h
63  * 3. prlong.h
64  *
65  * Unit tests are in base/time/pr_time_unittest.cc.
66  */
67 
68 #include "base/third_party/nspr/prtime.h"
69 
70 #include "base/check.h"
71 #include "build/build_config.h"
72 
73 #include <ctype.h>
74 #include <errno.h>  /* for EINVAL */
75 #include <limits.h>
76 #include <stddef.h>
77 #include <string.h>
78 #include <time.h>
79 
80 /*
81  * The COUNT_LEAPS macro counts the number of leap years passed by
82  * till the start of the given year Y.  At the start of the year 4
83  * A.D. the number of leap years passed by is 0, while at the start of
84  * the year 5 A.D. this count is 1. The number of years divisible by
85  * 100 but not divisible by 400 (the non-leap years) is deducted from
86  * the count to get the correct number of leap years.
87  *
88  * The COUNT_DAYS macro counts the number of days since 01/01/01 till the
89  * start of the given year Y. The number of days at the start of the year
90  * 1 is 0 while the number of days at the start of the year 2 is 365
91  * (which is ((2)-1) * 365) and so on. The reference point is 01/01/01
92  * midnight 00:00:00.
93  */
94 
95 #define COUNT_LEAPS(Y) (((Y)-1) / 4 - ((Y)-1) / 100 + ((Y)-1) / 400)
96 #define COUNT_DAYS(Y) (((Y)-1) * 365 + COUNT_LEAPS(Y))
97 #define DAYS_BETWEEN_YEARS(A, B) (COUNT_DAYS(B) - COUNT_DAYS(A))
98 
99 /* Implements the Unix localtime_r() function for windows */
100 #if BUILDFLAG(IS_WIN)
localtime_r(const time_t * secs,struct tm * time)101 static void localtime_r(const time_t* secs, struct tm* time) {
102   (void) localtime_s(time, secs);
103 }
104 #endif
105 
106 /*
107  * Static variables used by functions in this file
108  */
109 
110 /*
111  * The following array contains the day of year for the last day of
112  * each month, where index 1 is January, and day 0 is January 1.
113  */
114 
115 static const int lastDayOfMonth[2][13] = {
116     {-1, 30, 58, 89, 119, 150, 180, 211, 242, 272, 303, 333, 364},
117     {-1, 30, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365}
118 };
119 
120 /*
121  * The number of days in a month
122  */
123 
124 static const PRInt8 nDays[2][12] = {
125     {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
126     {31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}
127 };
128 
129 /*
130  *------------------------------------------------------------------------
131  *
132  * PR_ImplodeTime --
133  *
134  *     Cf. time_t mktime(struct tm *tp)
135  *     Note that 1 year has < 2^25 seconds.  So an PRInt32 is large enough.
136  *
137  *------------------------------------------------------------------------
138  */
139 PRTime
PR_ImplodeTime(const PRExplodedTime * exploded)140 PR_ImplodeTime(const PRExplodedTime *exploded)
141 {
142   PRExplodedTime copy;
143   PRTime retVal;
144   PRInt64 secPerDay, usecPerSec;
145   PRInt64 temp;
146   PRInt64 numSecs64;
147   PRInt32 numDays;
148   PRInt32 numSecs;
149 
150   /* Normalize first.  Do this on our copy */
151   copy = *exploded;
152   PR_NormalizeTime(&copy, PR_GMTParameters);
153 
154   numDays = DAYS_BETWEEN_YEARS(1970, copy.tm_year);
155 
156   numSecs = copy.tm_yday * 86400 + copy.tm_hour * 3600 + copy.tm_min * 60 +
157             copy.tm_sec;
158 
159   LL_I2L(temp, numDays);
160   LL_I2L(secPerDay, 86400);
161   LL_MUL(temp, temp, secPerDay);
162   LL_I2L(numSecs64, numSecs);
163   LL_ADD(numSecs64, numSecs64, temp);
164 
165   /* apply the GMT and DST offsets */
166   LL_I2L(temp, copy.tm_params.tp_gmt_offset);
167   LL_SUB(numSecs64, numSecs64, temp);
168   LL_I2L(temp, copy.tm_params.tp_dst_offset);
169   LL_SUB(numSecs64, numSecs64, temp);
170 
171   LL_I2L(usecPerSec, 1000000L);
172   LL_MUL(temp, numSecs64, usecPerSec);
173   LL_I2L(retVal, copy.tm_usec);
174   LL_ADD(retVal, retVal, temp);
175 
176   return retVal;
177 }
178 
179 /*
180  *-------------------------------------------------------------------------
181  *
182  * IsLeapYear --
183  *
184  *     Returns 1 if the year is a leap year, 0 otherwise.
185  *
186  *-------------------------------------------------------------------------
187  */
188 
IsLeapYear(PRInt16 year)189 static int IsLeapYear(PRInt16 year)
190 {
191     if ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0)
192         return 1;
193     else
194         return 0;
195 }
196 
197 /*
198  * 'secOffset' should be less than 86400 (i.e., a day).
199  * 'time' should point to a normalized PRExplodedTime.
200  */
201 
202 static void
ApplySecOffset(PRExplodedTime * time,PRInt32 secOffset)203 ApplySecOffset(PRExplodedTime *time, PRInt32 secOffset)
204 {
205     time->tm_sec += secOffset;
206 
207     /* Note that in this implementation we do not count leap seconds */
208     if (time->tm_sec < 0 || time->tm_sec >= 60) {
209         time->tm_min += time->tm_sec / 60;
210         time->tm_sec %= 60;
211         if (time->tm_sec < 0) {
212             time->tm_sec += 60;
213             time->tm_min--;
214         }
215     }
216 
217     if (time->tm_min < 0 || time->tm_min >= 60) {
218         time->tm_hour += time->tm_min / 60;
219         time->tm_min %= 60;
220         if (time->tm_min < 0) {
221             time->tm_min += 60;
222             time->tm_hour--;
223         }
224     }
225 
226     if (time->tm_hour < 0) {
227         /* Decrement mday, yday, and wday */
228         time->tm_hour += 24;
229         time->tm_mday--;
230         time->tm_yday--;
231         if (time->tm_mday < 1) {
232             time->tm_month--;
233             if (time->tm_month < 0) {
234                 time->tm_month = 11;
235                 time->tm_year--;
236                 if (IsLeapYear(time->tm_year))
237                     time->tm_yday = 365;
238                 else
239                     time->tm_yday = 364;
240             }
241             time->tm_mday = nDays[IsLeapYear(time->tm_year)][time->tm_month];
242         }
243         time->tm_wday--;
244         if (time->tm_wday < 0)
245             time->tm_wday = 6;
246     } else if (time->tm_hour > 23) {
247         /* Increment mday, yday, and wday */
248         time->tm_hour -= 24;
249         time->tm_mday++;
250         time->tm_yday++;
251         if (time->tm_mday >
252                 nDays[IsLeapYear(time->tm_year)][time->tm_month]) {
253             time->tm_mday = 1;
254             time->tm_month++;
255             if (time->tm_month > 11) {
256                 time->tm_month = 0;
257                 time->tm_year++;
258                 time->tm_yday = 0;
259             }
260         }
261         time->tm_wday++;
262         if (time->tm_wday > 6)
263             time->tm_wday = 0;
264     }
265 }
266 
267 void
PR_NormalizeTime(PRExplodedTime * time,PRTimeParamFn params)268 PR_NormalizeTime(PRExplodedTime *time, PRTimeParamFn params)
269 {
270     int daysInMonth;
271     PRInt32 numDays;
272 
273     /* Get back to GMT */
274     time->tm_sec -= time->tm_params.tp_gmt_offset
275             + time->tm_params.tp_dst_offset;
276     time->tm_params.tp_gmt_offset = 0;
277     time->tm_params.tp_dst_offset = 0;
278 
279     /* Now normalize GMT */
280 
281     if (time->tm_usec < 0 || time->tm_usec >= 1000000) {
282         time->tm_sec +=  time->tm_usec / 1000000;
283         time->tm_usec %= 1000000;
284         if (time->tm_usec < 0) {
285             time->tm_usec += 1000000;
286             time->tm_sec--;
287         }
288     }
289 
290     /* Note that we do not count leap seconds in this implementation */
291     if (time->tm_sec < 0 || time->tm_sec >= 60) {
292         time->tm_min += time->tm_sec / 60;
293         time->tm_sec %= 60;
294         if (time->tm_sec < 0) {
295             time->tm_sec += 60;
296             time->tm_min--;
297         }
298     }
299 
300     if (time->tm_min < 0 || time->tm_min >= 60) {
301         time->tm_hour += time->tm_min / 60;
302         time->tm_min %= 60;
303         if (time->tm_min < 0) {
304             time->tm_min += 60;
305             time->tm_hour--;
306         }
307     }
308 
309     if (time->tm_hour < 0 || time->tm_hour >= 24) {
310         time->tm_mday += time->tm_hour / 24;
311         time->tm_hour %= 24;
312         if (time->tm_hour < 0) {
313             time->tm_hour += 24;
314             time->tm_mday--;
315         }
316     }
317 
318     /* Normalize month and year before mday */
319     if (time->tm_month < 0 || time->tm_month >= 12) {
320         time->tm_year += static_cast<PRInt16>(time->tm_month / 12);
321         time->tm_month %= 12;
322         if (time->tm_month < 0) {
323             time->tm_month += 12;
324             time->tm_year--;
325         }
326     }
327 
328     /* Now that month and year are in proper range, normalize mday */
329 
330     if (time->tm_mday < 1) {
331         /* mday too small */
332         do {
333             /* the previous month */
334             time->tm_month--;
335             if (time->tm_month < 0) {
336                 time->tm_month = 11;
337                 time->tm_year--;
338             }
339             time->tm_mday += nDays[IsLeapYear(time->tm_year)][time->tm_month];
340         } while (time->tm_mday < 1);
341     } else {
342         daysInMonth = nDays[IsLeapYear(time->tm_year)][time->tm_month];
343         while (time->tm_mday > daysInMonth) {
344             /* mday too large */
345             time->tm_mday -= daysInMonth;
346             time->tm_month++;
347             if (time->tm_month > 11) {
348                 time->tm_month = 0;
349                 time->tm_year++;
350             }
351             daysInMonth = nDays[IsLeapYear(time->tm_year)][time->tm_month];
352         }
353     }
354 
355     /* Recompute yday and wday */
356     time->tm_yday = static_cast<PRInt16>(time->tm_mday +
357             lastDayOfMonth[IsLeapYear(time->tm_year)][time->tm_month]);
358 
359     numDays = DAYS_BETWEEN_YEARS(1970, time->tm_year) + time->tm_yday;
360     time->tm_wday = (numDays + 4) % 7;
361     if (time->tm_wday < 0) {
362         time->tm_wday += 7;
363     }
364 
365     /* Recompute time parameters */
366 
367     time->tm_params = params(time);
368 
369     ApplySecOffset(time, time->tm_params.tp_gmt_offset
370             + time->tm_params.tp_dst_offset);
371 }
372 
373 /*
374  *------------------------------------------------------------------------
375  *
376  * PR_GMTParameters --
377  *
378  *     Returns the PRTimeParameters for Greenwich Mean Time.
379  *     Trivially, both the tp_gmt_offset and tp_dst_offset fields are 0.
380  *
381  *------------------------------------------------------------------------
382  */
383 
384 PRTimeParameters
PR_GMTParameters(const PRExplodedTime * gmt)385 PR_GMTParameters(const PRExplodedTime *gmt)
386 {
387     PRTimeParameters retVal = { 0, 0 };
388     return retVal;
389 }
390 
391 /*
392  * The following code implements PR_ParseTimeString().  It is based on
393  * ns/lib/xp/xp_time.c, revision 1.25, by Jamie Zawinski <[email protected]>.
394  */
395 
396 /*
397  * We only recognize the abbreviations of a small subset of time zones
398  * in North America, Europe, and Japan.
399  *
400  * PST/PDT: Pacific Standard/Daylight Time
401  * MST/MDT: Mountain Standard/Daylight Time
402  * CST/CDT: Central Standard/Daylight Time
403  * EST/EDT: Eastern Standard/Daylight Time
404  * AST: Atlantic Standard Time
405  * NST: Newfoundland Standard Time
406  * GMT: Greenwich Mean Time
407  * BST: British Summer Time
408  * MET: Middle Europe Time
409  * EET: Eastern Europe Time
410  * JST: Japan Standard Time
411  */
412 
413 typedef enum
414 {
415   TT_UNKNOWN,
416 
417   TT_SUN, TT_MON, TT_TUE, TT_WED, TT_THU, TT_FRI, TT_SAT,
418 
419   TT_JAN, TT_FEB, TT_MAR, TT_APR, TT_MAY, TT_JUN,
420   TT_JUL, TT_AUG, TT_SEP, TT_OCT, TT_NOV, TT_DEC,
421 
422   TT_PST, TT_PDT, TT_MST, TT_MDT, TT_CST, TT_CDT, TT_EST, TT_EDT,
423   TT_AST, TT_NST, TT_GMT, TT_BST, TT_MET, TT_EET, TT_JST
424 } TIME_TOKEN;
425 
426 /*
427  * This parses a time/date string into a PRTime
428  * (microseconds after "1-Jan-1970 00:00:00 GMT").
429  * It returns PR_SUCCESS on success, and PR_FAILURE
430  * if the time/date string can't be parsed.
431  *
432  * Many formats are handled, including:
433  *
434  *   14 Apr 89 03:20:12
435  *   14 Apr 89 03:20 GMT
436  *   Fri, 17 Mar 89 4:01:33
437  *   Fri, 17 Mar 89 4:01 GMT
438  *   Mon Jan 16 16:12 PDT 1989
439  *   Mon Jan 16 16:12 +0130 1989
440  *   6 May 1992 16:41-JST (Wednesday)
441  *   22-AUG-1993 10:59:12.82
442  *   22-AUG-1993 10:59pm
443  *   22-AUG-1993 12:59am
444  *   22-AUG-1993 12:59 PM
445  *   Friday, August 04, 1995 3:54 PM
446  *   06/21/95 04:24:34 PM
447  *   20/06/95 21:07
448  *   95-06-08 19:32:48 EDT
449  *   1995-06-17T23:11:25.342156Z
450  *
451  * If the input string doesn't contain a description of the timezone,
452  * we consult the `default_to_gmt' to decide whether the string should
453  * be interpreted relative to the local time zone (PR_FALSE) or GMT (PR_TRUE).
454  * The correct value for this argument depends on what standard specified
455  * the time string which you are parsing.
456  */
457 
458 PRStatus
PR_ParseTimeString(const char * string,PRBool default_to_gmt,PRTime * result_imploded)459 PR_ParseTimeString(
460         const char *string,
461         PRBool default_to_gmt,
462         PRTime *result_imploded)
463 {
464   PRExplodedTime tm;
465   PRExplodedTime *result = &tm;
466   TIME_TOKEN dotw = TT_UNKNOWN;
467   TIME_TOKEN month = TT_UNKNOWN;
468   TIME_TOKEN zone = TT_UNKNOWN;
469   int zone_offset = -1;
470   int dst_offset = 0;
471   int date = -1;
472   PRInt32 year = -1;
473   int hour = -1;
474   int min = -1;
475   int sec = -1;
476   int usec = -1;
477 
478   const char *rest = string;
479 
480   int iterations = 0;
481 
482   PR_ASSERT(string && result);
483   if (!string || !result) return PR_FAILURE;
484 
485   while (*rest)
486         {
487 
488           if (iterations++ > 1000)
489                 {
490                   return PR_FAILURE;
491                 }
492 
493           switch (*rest)
494                 {
495                 case 'a': case 'A':
496                   if (month == TT_UNKNOWN &&
497                           (rest[1] == 'p' || rest[1] == 'P') &&
498                           (rest[2] == 'r' || rest[2] == 'R'))
499                         month = TT_APR;
500                   else if (zone == TT_UNKNOWN &&
501                                    (rest[1] == 's' || rest[1] == 'S') &&
502                                    (rest[2] == 't' || rest[2] == 'T'))
503                         zone = TT_AST;
504                   else if (month == TT_UNKNOWN &&
505                                    (rest[1] == 'u' || rest[1] == 'U') &&
506                                    (rest[2] == 'g' || rest[2] == 'G'))
507                         month = TT_AUG;
508                   break;
509                 case 'b': case 'B':
510                   if (zone == TT_UNKNOWN &&
511                           (rest[1] == 's' || rest[1] == 'S') &&
512                           (rest[2] == 't' || rest[2] == 'T'))
513                         zone = TT_BST;
514                   break;
515                 case 'c': case 'C':
516                   if (zone == TT_UNKNOWN &&
517                           (rest[1] == 'd' || rest[1] == 'D') &&
518                           (rest[2] == 't' || rest[2] == 'T'))
519                         zone = TT_CDT;
520                   else if (zone == TT_UNKNOWN &&
521                                    (rest[1] == 's' || rest[1] == 'S') &&
522                                    (rest[2] == 't' || rest[2] == 'T'))
523                         zone = TT_CST;
524                   break;
525                 case 'd': case 'D':
526                   if (month == TT_UNKNOWN &&
527                           (rest[1] == 'e' || rest[1] == 'E') &&
528                           (rest[2] == 'c' || rest[2] == 'C'))
529                         month = TT_DEC;
530                   break;
531                 case 'e': case 'E':
532                   if (zone == TT_UNKNOWN &&
533                           (rest[1] == 'd' || rest[1] == 'D') &&
534                           (rest[2] == 't' || rest[2] == 'T'))
535                         zone = TT_EDT;
536                   else if (zone == TT_UNKNOWN &&
537                                    (rest[1] == 'e' || rest[1] == 'E') &&
538                                    (rest[2] == 't' || rest[2] == 'T'))
539                         zone = TT_EET;
540                   else if (zone == TT_UNKNOWN &&
541                                    (rest[1] == 's' || rest[1] == 'S') &&
542                                    (rest[2] == 't' || rest[2] == 'T'))
543                         zone = TT_EST;
544                   break;
545                 case 'f': case 'F':
546                   if (month == TT_UNKNOWN &&
547                           (rest[1] == 'e' || rest[1] == 'E') &&
548                           (rest[2] == 'b' || rest[2] == 'B'))
549                         month = TT_FEB;
550                   else if (dotw == TT_UNKNOWN &&
551                                    (rest[1] == 'r' || rest[1] == 'R') &&
552                                    (rest[2] == 'i' || rest[2] == 'I'))
553                         dotw = TT_FRI;
554                   break;
555                 case 'g': case 'G':
556                   if (zone == TT_UNKNOWN &&
557                           (rest[1] == 'm' || rest[1] == 'M') &&
558                           (rest[2] == 't' || rest[2] == 'T'))
559                         zone = TT_GMT;
560                   break;
561                 case 'j': case 'J':
562                   if (month == TT_UNKNOWN &&
563                           (rest[1] == 'a' || rest[1] == 'A') &&
564                           (rest[2] == 'n' || rest[2] == 'N'))
565                         month = TT_JAN;
566                   else if (zone == TT_UNKNOWN &&
567                                    (rest[1] == 's' || rest[1] == 'S') &&
568                                    (rest[2] == 't' || rest[2] == 'T'))
569                         zone = TT_JST;
570                   else if (month == TT_UNKNOWN &&
571                                    (rest[1] == 'u' || rest[1] == 'U') &&
572                                    (rest[2] == 'l' || rest[2] == 'L'))
573                         month = TT_JUL;
574                   else if (month == TT_UNKNOWN &&
575                                    (rest[1] == 'u' || rest[1] == 'U') &&
576                                    (rest[2] == 'n' || rest[2] == 'N'))
577                         month = TT_JUN;
578                   break;
579                 case 'm': case 'M':
580                   if (month == TT_UNKNOWN &&
581                           (rest[1] == 'a' || rest[1] == 'A') &&
582                           (rest[2] == 'r' || rest[2] == 'R'))
583                         month = TT_MAR;
584                   else if (month == TT_UNKNOWN &&
585                                    (rest[1] == 'a' || rest[1] == 'A') &&
586                                    (rest[2] == 'y' || rest[2] == 'Y'))
587                         month = TT_MAY;
588                   else if (zone == TT_UNKNOWN &&
589                                    (rest[1] == 'd' || rest[1] == 'D') &&
590                                    (rest[2] == 't' || rest[2] == 'T'))
591                         zone = TT_MDT;
592                   else if (zone == TT_UNKNOWN &&
593                                    (rest[1] == 'e' || rest[1] == 'E') &&
594                                    (rest[2] == 't' || rest[2] == 'T'))
595                         zone = TT_MET;
596                   else if (dotw == TT_UNKNOWN &&
597                                    (rest[1] == 'o' || rest[1] == 'O') &&
598                                    (rest[2] == 'n' || rest[2] == 'N'))
599                         dotw = TT_MON;
600                   else if (zone == TT_UNKNOWN &&
601                                    (rest[1] == 's' || rest[1] == 'S') &&
602                                    (rest[2] == 't' || rest[2] == 'T'))
603                         zone = TT_MST;
604                   break;
605                 case 'n': case 'N':
606                   if (month == TT_UNKNOWN &&
607                           (rest[1] == 'o' || rest[1] == 'O') &&
608                           (rest[2] == 'v' || rest[2] == 'V'))
609                         month = TT_NOV;
610                   else if (zone == TT_UNKNOWN &&
611                                    (rest[1] == 's' || rest[1] == 'S') &&
612                                    (rest[2] == 't' || rest[2] == 'T'))
613                         zone = TT_NST;
614                   break;
615                 case 'o': case 'O':
616                   if (month == TT_UNKNOWN &&
617                           (rest[1] == 'c' || rest[1] == 'C') &&
618                           (rest[2] == 't' || rest[2] == 'T'))
619                         month = TT_OCT;
620                   break;
621                 case 'p': case 'P':
622                   if (zone == TT_UNKNOWN &&
623                           (rest[1] == 'd' || rest[1] == 'D') &&
624                           (rest[2] == 't' || rest[2] == 'T'))
625                         zone = TT_PDT;
626                   else if (zone == TT_UNKNOWN &&
627                                    (rest[1] == 's' || rest[1] == 'S') &&
628                                    (rest[2] == 't' || rest[2] == 'T'))
629                         zone = TT_PST;
630                   break;
631                 case 's': case 'S':
632                   if (dotw == TT_UNKNOWN &&
633                           (rest[1] == 'a' || rest[1] == 'A') &&
634                           (rest[2] == 't' || rest[2] == 'T'))
635                         dotw = TT_SAT;
636                   else if (month == TT_UNKNOWN &&
637                                    (rest[1] == 'e' || rest[1] == 'E') &&
638                                    (rest[2] == 'p' || rest[2] == 'P'))
639                         month = TT_SEP;
640                   else if (dotw == TT_UNKNOWN &&
641                                    (rest[1] == 'u' || rest[1] == 'U') &&
642                                    (rest[2] == 'n' || rest[2] == 'N'))
643                         dotw = TT_SUN;
644                   break;
645                 case 't': case 'T':
646                   if (dotw == TT_UNKNOWN &&
647                           (rest[1] == 'h' || rest[1] == 'H') &&
648                           (rest[2] == 'u' || rest[2] == 'U'))
649                         dotw = TT_THU;
650                   else if (dotw == TT_UNKNOWN &&
651                                    (rest[1] == 'u' || rest[1] == 'U') &&
652                                    (rest[2] == 'e' || rest[2] == 'E'))
653                         dotw = TT_TUE;
654                   break;
655                 case 'u': case 'U':
656                   if (zone == TT_UNKNOWN &&
657                           (rest[1] == 't' || rest[1] == 'T') &&
658                           !(rest[2] >= 'A' && rest[2] <= 'Z') &&
659                           !(rest[2] >= 'a' && rest[2] <= 'z'))
660                         /* UT is the same as GMT but UTx is not. */
661                         zone = TT_GMT;
662                   break;
663                 case 'w': case 'W':
664                   if (dotw == TT_UNKNOWN &&
665                           (rest[1] == 'e' || rest[1] == 'E') &&
666                           (rest[2] == 'd' || rest[2] == 'D'))
667                         dotw = TT_WED;
668                   break;
669 
670                 case '+': case '-':
671                   {
672                         const char *end;
673                         int sign;
674                         if (zone_offset != -1)
675                           {
676                                 /* already got one... */
677                                 rest++;
678                                 break;
679                           }
680                         if (zone != TT_UNKNOWN && zone != TT_GMT)
681                           {
682                                 /* GMT+0300 is legal, but PST+0300 is not. */
683                                 rest++;
684                                 break;
685                           }
686 
687                         sign = ((*rest == '+') ? 1 : -1);
688                         rest++; /* move over sign */
689                         end = rest;
690                         while (*end >= '0' && *end <= '9')
691                           end++;
692                         if (rest == end) /* no digits here */
693                           break;
694 
695                         if ((end - rest) == 4)
696                           /* offset in HHMM */
697                           zone_offset = (((((rest[0]-'0')*10) + (rest[1]-'0')) * 60) +
698                                                          (((rest[2]-'0')*10) + (rest[3]-'0')));
699                         else if ((end - rest) == 2)
700                           /* offset in hours */
701                           zone_offset = (((rest[0]-'0')*10) + (rest[1]-'0')) * 60;
702                         else if ((end - rest) == 1)
703                           /* offset in hours */
704                           zone_offset = (rest[0]-'0') * 60;
705                         else
706                           /* 3 or >4 */
707                           break;
708 
709                         zone_offset *= sign;
710                         zone = TT_GMT;
711                         break;
712                   }
713 
714                 case '0': case '1': case '2': case '3': case '4':
715                 case '5': case '6': case '7': case '8': case '9':
716                   {
717                         int tmp_hour = -1;
718                         int tmp_min = -1;
719                         int tmp_sec = -1;
720                         int tmp_usec = -1;
721                         const char *end = rest + 1;
722                         while (*end >= '0' && *end <= '9')
723                           end++;
724 
725                         /* end is now the first character after a range of digits. */
726 
727                         if (*end == ':')
728                           {
729                                 if (hour >= 0 && min >= 0) /* already got it */
730                                   break;
731 
732                                 /* We have seen "[0-9]+:", so this is probably HH:MM[:SS] */
733                                 if ((end - rest) > 2)
734                                   /* it is [0-9][0-9][0-9]+: */
735                                   break;
736                                 else if ((end - rest) == 2)
737                                   tmp_hour = ((rest[0]-'0')*10 +
738                                                           (rest[1]-'0'));
739                                 else
740                                   tmp_hour = (rest[0]-'0');
741 
742                                 /* move over the colon, and parse minutes */
743 
744                                 rest = ++end;
745                                 while (*end >= '0' && *end <= '9')
746                                   end++;
747 
748                                 if (end == rest)
749                                   /* no digits after first colon? */
750                                   break;
751                                 else if ((end - rest) > 2)
752                                   /* it is [0-9][0-9][0-9]+: */
753                                   break;
754                                 else if ((end - rest) == 2)
755                                   tmp_min = ((rest[0]-'0')*10 +
756                                                          (rest[1]-'0'));
757                                 else
758                                   tmp_min = (rest[0]-'0');
759 
760                                 /* now go for seconds */
761                                 rest = end;
762                                 if (*rest == ':')
763                                   rest++;
764                                 end = rest;
765                                 while (*end >= '0' && *end <= '9')
766                                   end++;
767 
768                                 if (end == rest)
769                                   /* no digits after second colon - that's ok. */
770                                   ;
771                                 else if ((end - rest) > 2)
772                                   /* it is [0-9][0-9][0-9]+: */
773                                   break;
774                                 else if ((end - rest) == 2)
775                                   tmp_sec = ((rest[0]-'0')*10 +
776                                                          (rest[1]-'0'));
777                                 else
778                                   tmp_sec = (rest[0]-'0');
779 
780                                 /* fractional second */
781                                 rest = end;
782                                 if (*rest == '.')
783                                   {
784                                     rest++;
785                                     end++;
786                                     tmp_usec = 0;
787                                     /* use up to 6 digits, skip over the rest */
788                                     while (*end >= '0' && *end <= '9')
789                                       {
790                                         if (end - rest < 6)
791                                           tmp_usec = tmp_usec * 10 + *end - '0';
792                                         end++;
793                                       }
794                                     ptrdiff_t ndigits = end - rest;
795                                     while (ndigits++ < 6)
796                                       tmp_usec *= 10;
797                                     rest = end;
798                                   }
799 
800                                 if (*rest == 'Z')
801                                   {
802                                     zone = TT_GMT;
803                                     rest++;
804                                   }
805                                 else if (tmp_hour <= 12)
806                                   {
807                                     /* If we made it here, we've parsed hour and min,
808                                        and possibly sec, so the current token is a time.
809                                        Now skip over whitespace and see if there's an AM
810                                        or PM directly following the time.
811                                     */
812                                         const char *s = end;
813                                         while (*s && (*s == ' ' || *s == '\t'))
814                                           s++;
815                                         if ((s[0] == 'p' || s[0] == 'P') &&
816                                                 (s[1] == 'm' || s[1] == 'M'))
817                                           /* 10:05pm == 22:05, and 12:05pm == 12:05 */
818                                           tmp_hour = (tmp_hour == 12 ? 12 : tmp_hour + 12);
819                                         else if (tmp_hour == 12 &&
820                                                          (s[0] == 'a' || s[0] == 'A') &&
821                                                          (s[1] == 'm' || s[1] == 'M'))
822                                           /* 12:05am == 00:05 */
823                                           tmp_hour = 0;
824                                   }
825 
826                                 hour = tmp_hour;
827                                 min = tmp_min;
828                                 sec = tmp_sec;
829                                 usec = tmp_usec;
830                                 rest = end;
831                                 break;
832                           }
833                         else if ((*end == '/' || *end == '-') &&
834                                          end[1] >= '0' && end[1] <= '9')
835                           {
836                                 /* Perhaps this is 6/16/95, 16/6/95, 6-16-95, or 16-6-95
837                                    or even 95-06-05 or 1995-06-22.
838                                  */
839                                 int n1, n2, n3;
840                                 const char *s;
841 
842                                 if (month != TT_UNKNOWN)
843                                   /* if we saw a month name, this can't be. */
844                                   break;
845 
846                                 s = rest;
847 
848                                 n1 = (*s++ - '0');                                /* first 1, 2 or 4 digits */
849                                 if (*s >= '0' && *s <= '9')
850                                   {
851                                     n1 = n1*10 + (*s++ - '0');
852 
853                                     if (*s >= '0' && *s <= '9')            /* optional digits 3 and 4 */
854                                       {
855                                         n1 = n1*10 + (*s++ - '0');
856                                         if (*s < '0' || *s > '9')
857                                           break;
858                                         n1 = n1*10 + (*s++ - '0');
859                                       }
860                                   }
861 
862                                 if (*s != '/' && *s != '-')                /* slash */
863                                   break;
864                                 s++;
865 
866                                 if (*s < '0' || *s > '9')                /* second 1 or 2 digits */
867                                   break;
868                                 n2 = (*s++ - '0');
869                                 if (*s >= '0' && *s <= '9')
870                                   n2 = n2*10 + (*s++ - '0');
871 
872                                 if (*s != '/' && *s != '-')                /* slash */
873                                   break;
874                                 s++;
875 
876                                 if (*s < '0' || *s > '9')                /* third 1, 2, 4, or 5 digits */
877                                   break;
878                                 n3 = (*s++ - '0');
879                                 if (*s >= '0' && *s <= '9')
880                                   n3 = n3*10 + (*s++ - '0');
881 
882                                 if (*s >= '0' && *s <= '9')            /* optional digits 3, 4, and 5 */
883                                   {
884                                         n3 = n3*10 + (*s++ - '0');
885                                         if (*s < '0' || *s > '9')
886                                           break;
887                                         n3 = n3*10 + (*s++ - '0');
888                                         if (*s >= '0' && *s <= '9')
889                                           n3 = n3*10 + (*s++ - '0');
890                                   }
891 
892                                 if (*s == 'T' && s[1] >= '0' && s[1] <= '9')
893                                   /* followed by ISO 8601 T delimiter and number is ok */
894                                   ;
895                                 else if ((*s >= '0' && *s <= '9') ||
896                                          (*s >= 'A' && *s <= 'Z') ||
897                                          (*s >= 'a' && *s <= 'z'))
898                                   /* but other alphanumerics are not ok */
899                                   break;
900 
901                                 /* Ok, we parsed three multi-digit numbers, with / or -
902                                    between them.  Now decide what the hell they are
903                                    (DD/MM/YY or MM/DD/YY or [YY]YY/MM/DD.)
904                                  */
905 
906                                 if (n1 > 31 || n1 == 0)  /* must be [YY]YY/MM/DD */
907                                   {
908                                         if (n2 > 12) break;
909                                         if (n3 > 31) break;
910                                         year = n1;
911                                         if (year < 70)
912                                             year += 2000;
913                                         else if (year < 100)
914                                             year += 1900;
915                                         month = (TIME_TOKEN)(n2 + ((int)TT_JAN) - 1);
916                                         date = n3;
917                                         rest = s;
918                                         break;
919                                   }
920 
921                                 if (n1 > 12 && n2 > 12)  /* illegal */
922                                   {
923                                         rest = s;
924                                         break;
925                                   }
926 
927                                 if (n3 < 70)
928                                     n3 += 2000;
929                                 else if (n3 < 100)
930                                     n3 += 1900;
931 
932                                 if (n1 > 12)  /* must be DD/MM/YY */
933                                   {
934                                         date = n1;
935                                         month = (TIME_TOKEN)(n2 + ((int)TT_JAN) - 1);
936                                         year = n3;
937                                   }
938                                 else                  /* assume MM/DD/YY */
939                                   {
940                                         /* #### In the ambiguous case, should we consult the
941                                            locale to find out the local default? */
942                                         month = (TIME_TOKEN)(n1 + ((int)TT_JAN) - 1);
943                                         date = n2;
944                                         year = n3;
945                                   }
946                                 rest = s;
947                           }
948                         else if ((*end >= 'A' && *end <= 'Z') ||
949                                          (*end >= 'a' && *end <= 'z'))
950                           /* Digits followed by non-punctuation - what's that? */
951                           ;
952                         else if ((end - rest) == 5)                /* five digits is a year */
953                           year = (year < 0
954                                           ? ((rest[0]-'0')*10000L +
955                                                  (rest[1]-'0')*1000L +
956                                                  (rest[2]-'0')*100L +
957                                                  (rest[3]-'0')*10L +
958                                                  (rest[4]-'0'))
959                                           : year);
960                         else if ((end - rest) == 4)                /* four digits is a year */
961                           year = (year < 0
962                                           ? ((rest[0]-'0')*1000L +
963                                                  (rest[1]-'0')*100L +
964                                                  (rest[2]-'0')*10L +
965                                                  (rest[3]-'0'))
966                                           : year);
967                         else if ((end - rest) == 2)                /* two digits - date or year */
968                           {
969                                 int n = ((rest[0]-'0')*10 +
970                                                  (rest[1]-'0'));
971                                 /* If we don't have a date (day of the month) and we see a number
972                                      less than 32, then assume that is the date.
973 
974                                          Otherwise, if we have a date and not a year, assume this is the
975                                          year.  If it is less than 70, then assume it refers to the 21st
976                                          century.  If it is two digits (>= 70), assume it refers to this
977                                          century.  Otherwise, assume it refers to an unambiguous year.
978 
979                                          The world will surely end soon.
980                                    */
981                                 if (date < 0 && n < 32)
982                                   date = n;
983                                 else if (year < 0)
984                                   {
985                                         if (n < 70)
986                                           year = 2000 + n;
987                                         else if (n < 100)
988                                           year = 1900 + n;
989                                         else
990                                           year = n;
991                                   }
992                                 /* else what the hell is this. */
993                           }
994                         else if ((end - rest) == 1)                /* one digit - date */
995                           date = (date < 0 ? (rest[0]-'0') : date);
996                         /* else, three or more than five digits - what's that? */
997 
998                         break;
999                   }   /* case '0' .. '9' */
1000                 }   /* switch */
1001 
1002           /* Skip to the end of this token, whether we parsed it or not.
1003              Tokens are delimited by whitespace, or ,;-+/()[] but explicitly not .:
1004              'T' is also treated as delimiter when followed by a digit (ISO 8601).
1005            */
1006           while (*rest &&
1007                          *rest != ' ' && *rest != '\t' &&
1008                          *rest != ',' && *rest != ';' &&
1009                          *rest != '-' && *rest != '+' &&
1010                          *rest != '/' &&
1011                          *rest != '(' && *rest != ')' && *rest != '[' && *rest != ']' &&
1012                          !(*rest == 'T' && rest[1] >= '0' && rest[1] <= '9')
1013                 )
1014                 rest++;
1015           /* skip over uninteresting chars. */
1016         SKIP_MORE:
1017           while (*rest == ' ' || *rest == '\t' ||
1018                  *rest == ',' || *rest == ';' || *rest == '/' ||
1019                  *rest == '(' || *rest == ')' || *rest == '[' || *rest == ']')
1020                 rest++;
1021 
1022           /* "-" is ignored at the beginning of a token if we have not yet
1023                  parsed a year (e.g., the second "-" in "30-AUG-1966"), or if
1024                  the character after the dash is not a digit. */
1025           if (*rest == '-' && ((rest > string &&
1026               isalpha((unsigned char)rest[-1]) && year < 0) ||
1027               rest[1] < '0' || rest[1] > '9'))
1028                 {
1029                   rest++;
1030                   goto SKIP_MORE;
1031                 }
1032 
1033           /* Skip T that may precede ISO 8601 time. */
1034           if (*rest == 'T' && rest[1] >= '0' && rest[1] <= '9')
1035             rest++;
1036         }   /* while */
1037 
1038   if (zone != TT_UNKNOWN && zone_offset == -1)
1039         {
1040           switch (zone)
1041                 {
1042                 case TT_PST: zone_offset = -8 * 60; break;
1043                 case TT_PDT: zone_offset = -8 * 60; dst_offset = 1 * 60; break;
1044                 case TT_MST: zone_offset = -7 * 60; break;
1045                 case TT_MDT: zone_offset = -7 * 60; dst_offset = 1 * 60; break;
1046                 case TT_CST: zone_offset = -6 * 60; break;
1047                 case TT_CDT: zone_offset = -6 * 60; dst_offset = 1 * 60; break;
1048                 case TT_EST: zone_offset = -5 * 60; break;
1049                 case TT_EDT: zone_offset = -5 * 60; dst_offset = 1 * 60; break;
1050                 case TT_AST: zone_offset = -4 * 60; break;
1051                 case TT_NST: zone_offset = -3 * 60 - 30; break;
1052                 case TT_GMT: zone_offset =  0 * 60; break;
1053                 case TT_BST: zone_offset =  0 * 60; dst_offset = 1 * 60; break;
1054                 case TT_MET: zone_offset =  1 * 60; break;
1055                 case TT_EET: zone_offset =  2 * 60; break;
1056                 case TT_JST: zone_offset =  9 * 60; break;
1057                 default:
1058                   PR_ASSERT (0);
1059                   break;
1060                 }
1061         }
1062 
1063   /* If we didn't find a year, month, or day-of-the-month, we can't
1064          possibly parse this, and in fact, mktime() will do something random
1065          (I'm seeing it return "Tue Feb  5 06:28:16 2036", which is no doubt
1066          a numerologically significant date... */
1067   if (month == TT_UNKNOWN || date == -1 || year == -1 || year > PR_INT16_MAX)
1068       return PR_FAILURE;
1069 
1070   memset(result, 0, sizeof(*result));
1071   if (usec != -1)
1072         result->tm_usec = usec;
1073   if (sec != -1)
1074         result->tm_sec = sec;
1075   if (min != -1)
1076         result->tm_min = min;
1077   if (hour != -1)
1078         result->tm_hour = hour;
1079   if (date != -1)
1080         result->tm_mday = date;
1081   if (month != TT_UNKNOWN)
1082         result->tm_month = (((int)month) - ((int)TT_JAN));
1083   if (year != -1)
1084         result->tm_year = static_cast<PRInt16>(year);
1085   if (dotw != TT_UNKNOWN)
1086         result->tm_wday = static_cast<PRInt8>(((int)dotw) - ((int)TT_SUN));
1087   /*
1088    * Mainly to compute wday and yday, but normalized time is also required
1089    * by the check below that works around a Visual C++ 2005 mktime problem.
1090    */
1091   PR_NormalizeTime(result, PR_GMTParameters);
1092   /* The remaining work is to set the gmt and dst offsets in tm_params. */
1093 
1094   if (zone == TT_UNKNOWN && default_to_gmt)
1095         {
1096           /* No zone was specified, so pretend the zone was GMT. */
1097           zone = TT_GMT;
1098           zone_offset = 0;
1099         }
1100 
1101   if (zone_offset == -1)
1102          {
1103            /* no zone was specified, and we're to assume that everything
1104              is local. */
1105           struct tm localTime;
1106           time_t secs;
1107 
1108           PR_ASSERT(result->tm_month > -1 &&
1109                     result->tm_mday > 0 &&
1110                     result->tm_hour > -1 &&
1111                     result->tm_min > -1 &&
1112                     result->tm_sec > -1);
1113 
1114             /*
1115              * To obtain time_t from a tm structure representing the local
1116              * time, we call mktime().  However, we need to see if we are
1117              * on 1-Jan-1970 or before.  If we are, we can't call mktime()
1118              * because mktime() will crash on win16. In that case, we
1119              * calculate zone_offset based on the zone offset at
1120              * 00:00:00, 2 Jan 1970 GMT, and subtract zone_offset from the
1121              * date we are parsing to transform the date to GMT.  We also
1122              * do so if mktime() returns (time_t) -1 (time out of range).
1123            */
1124 
1125           /* month, day, hours, mins and secs are always non-negative
1126              so we dont need to worry about them. */
1127           if (result->tm_year >= 1970)
1128                 {
1129                   localTime.tm_sec = result->tm_sec;
1130                   localTime.tm_min = result->tm_min;
1131                   localTime.tm_hour = result->tm_hour;
1132                   localTime.tm_mday = result->tm_mday;
1133                   localTime.tm_mon = result->tm_month;
1134                   localTime.tm_year = result->tm_year - 1900;
1135                   /* Set this to -1 to tell mktime "I don't care".  If you set
1136                      it to 0 or 1, you are making assertions about whether the
1137                      date you are handing it is in daylight savings mode or not;
1138                      and if you're wrong, it will "fix" it for you. */
1139                   localTime.tm_isdst = -1;
1140 
1141 #if _MSC_VER == 1400  /* 1400 = Visual C++ 2005 (8.0) */
1142                   /*
1143                    * mktime will return (time_t) -1 if the input is a date
1144                    * after 23:59:59, December 31, 3000, US Pacific Time (not
1145                    * UTC as documented):
1146                    * http://msdn.microsoft.com/en-us/library/d1y53h2a(VS.80).aspx
1147                    * But if the year is 3001, mktime also invokes the invalid
1148                    * parameter handler, causing the application to crash.  This
1149                    * problem has been reported in
1150                    * http://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=266036.
1151                    * We avoid this crash by not calling mktime if the date is
1152                    * out of range.  To use a simple test that works in any time
1153                    * zone, we consider year 3000 out of range as well.  (See
1154                    * bug 480740.)
1155                    */
1156                   if (result->tm_year >= 3000) {
1157                       /* Emulate what mktime would have done. */
1158                       errno = EINVAL;
1159                       secs = (time_t) -1;
1160                   } else {
1161                       secs = mktime(&localTime);
1162                   }
1163 #else
1164                   secs = mktime(&localTime);
1165 #endif
1166                   if (secs != (time_t) -1)
1167                     {
1168                     *result_imploded = secs * (PRTime)PR_USEC_PER_SEC;
1169                     *result_imploded += result->tm_usec;
1170                     return PR_SUCCESS;
1171                     }
1172                 }
1173 
1174                 /* So mktime() can't handle this case.  We assume the
1175                    zone_offset for the date we are parsing is the same as
1176                    the zone offset on 00:00:00 2 Jan 1970 GMT. */
1177                 secs = 86400;
1178                 localtime_r(&secs, &localTime);
1179                 zone_offset = localTime.tm_min
1180                               + 60 * localTime.tm_hour
1181                               + 1440 * (localTime.tm_mday - 2);
1182         }
1183 
1184   result->tm_params.tp_gmt_offset = zone_offset * 60;
1185   result->tm_params.tp_dst_offset = dst_offset * 60;
1186 
1187   *result_imploded = PR_ImplodeTime(result);
1188   return PR_SUCCESS;
1189 }
1190