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Time functions in time64.c need thread context on VMS.
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a272e669
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1/*
2
3Copyright (c) 2007-2008 Michael G Schwern
4
5This software originally derived from Paul Sheer's pivotal_gmtime_r.c.
6
7The MIT License:
8
9Permission is hereby granted, free of charge, to any person obtaining a copy
10of this software and associated documentation files (the "Software"), to deal
11in the Software without restriction, including without limitation the rights
12to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
13copies of the Software, and to permit persons to whom the Software is
14furnished to do so, subject to the following conditions:
15
16The above copyright notice and this permission notice shall be included in
17all copies or substantial portions of the Software.
18
19THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
20IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
22AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
23LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
24OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
25THE SOFTWARE.
26
27*/
28
29/*
30
31Programmers who have available to them 64-bit time values as a 'long
32long' type can use localtime64_r() and gmtime64_r() which correctly
33converts the time even on 32-bit systems. Whether you have 64-bit time
34values will depend on the operating system.
35
7430375d 36S_localtime64_r() is a 64-bit equivalent of localtime_r().
a272e669 37
7430375d 38S_gmtime64_r() is a 64-bit equivalent of gmtime_r().
a272e669
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39
40*/
41
7643e68f 42#include "time64.h"
af9b2bf5 43
4bb2f1fc 44static const char days_in_month[2][12] = {
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45 {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
46 {31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
47};
48
4bb2f1fc 49static const short julian_days_by_month[2][12] = {
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50 {0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334},
51 {0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335},
52};
53
4bb2f1fc 54static const short length_of_year[2] = { 365, 366 };
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55
56/* Number of days in a 400 year Gregorian cycle */
806a119a 57static const Year years_in_gregorian_cycle = 400;
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58static const int days_in_gregorian_cycle = (365 * 400) + 100 - 4 + 1;
59
60/* 28 year calendar cycle between 2010 and 2037 */
806a119a 61#define SOLAR_CYCLE_LENGTH 28
4bb2f1fc 62static const short safe_years[SOLAR_CYCLE_LENGTH] = {
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63 2016, 2017, 2018, 2019,
64 2020, 2021, 2022, 2023,
65 2024, 2025, 2026, 2027,
66 2028, 2029, 2030, 2031,
67 2032, 2033, 2034, 2035,
68 2036, 2037, 2010, 2011,
69 2012, 2013, 2014, 2015
70};
71
4bb2f1fc 72static const char dow_year_start[SOLAR_CYCLE_LENGTH] = {
003c3b95
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73 5, 0, 1, 2, /* 0 2016 - 2019 */
74 3, 5, 6, 0, /* 4 */
75 1, 3, 4, 5, /* 8 */
76 6, 1, 2, 3, /* 12 */
77 4, 6, 0, 1, /* 16 */
78 2, 4, 5, 6, /* 20 2036, 2037, 2010, 2011 */
79 0, 2, 3, 4 /* 24 2012, 2013, 2014, 2015 */
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80};
81
9af24521
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82/* Let's assume people are going to be looking for dates in the future.
83 Let's provide some cheats so you can skip ahead.
84 This has a 4x speed boost when near 2008.
85*/
86/* Number of days since epoch on Jan 1st, 2008 GMT */
87#define CHEAT_DAYS (1199145600 / 24 / 60 / 60)
88#define CHEAT_YEARS 108
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89
90#define IS_LEAP(n) ((!(((n) + 1900) % 400) || (!(((n) + 1900) % 4) && (((n) + 1900) % 100))) != 0)
91#define WRAP(a,b,m) ((a) = ((a) < 0 ) ? ((b)--, (a) + (m)) : (a))
92
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93#ifdef USE_SYSTEM_LOCALTIME
94# define SHOULD_USE_SYSTEM_LOCALTIME(a) ( \
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95 (a) <= SYSTEM_LOCALTIME_MAX && \
96 (a) >= SYSTEM_LOCALTIME_MIN \
97)
b86b480f
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98#else
99# define SHOULD_USE_SYSTEM_LOCALTIME(a) (0)
100#endif
101
102#ifdef USE_SYSTEM_GMTIME
103# define SHOULD_USE_SYSTEM_GMTIME(a) ( \
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104 (a) <= SYSTEM_GMTIME_MAX && \
105 (a) >= SYSTEM_GMTIME_MIN \
106)
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107#else
108# define SHOULD_USE_SYSTEM_GMTIME(a) (0)
109#endif
a64acb40 110
d4fb0a1f 111/* Multi varadic macros are a C99 thing, alas */
461d5a49 112#ifdef TIME_64_DEBUG
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113# define TIME64_TRACE(format) (fprintf(stderr, format))
114# define TIME64_TRACE1(format, var1) (fprintf(stderr, format, var1))
115# define TIME64_TRACE2(format, var1, var2) (fprintf(stderr, format, var1, var2))
116# define TIME64_TRACE3(format, var1, var2, var3) (fprintf(stderr, format, var1, var2, var3))
461d5a49 117#else
7430375d
CB
118# define TIME64_TRACE(format) ((void)0)
119# define TIME64_TRACE1(format, var1) ((void)0)
120# define TIME64_TRACE2(format, var1, var2) ((void)0)
121# define TIME64_TRACE3(format, var1, var2, var3) ((void)0)
461d5a49 122#endif
a64acb40 123
7430375d 124static int S_is_exception_century(Year year)
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125{
126 int is_exception = ((year % 100 == 0) && !(year % 400 == 0));
7430375d 127 TIME64_TRACE1("# is_exception_century: %s\n", is_exception ? "yes" : "no");
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128
129 return(is_exception);
130}
131
9af24521 132
7430375d 133static Time64_T S_timegm64(struct TM *date) {
b86b480f
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134 int days = 0;
135 Time64_T seconds = 0;
136 Year year;
a272e669 137
9af24521
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138 if( date->tm_year > 70 ) {
139 year = 70;
140 while( year < date->tm_year ) {
141 days += length_of_year[IS_LEAP(year)];
142 year++;
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143 }
144 }
9af24521
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145 else if ( date->tm_year < 70 ) {
146 year = 69;
147 do {
148 days -= length_of_year[IS_LEAP(year)];
149 year--;
150 } while( year >= date->tm_year );
151 }
152
153 days += julian_days_by_month[IS_LEAP(date->tm_year)][date->tm_mon];
154 days += date->tm_mday - 1;
155
ea722b76
MS
156 /* Avoid overflowing the days integer */
157 seconds = days;
158 seconds = seconds * 60 * 60 * 24;
159
9af24521
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160 seconds += date->tm_hour * 60 * 60;
161 seconds += date->tm_min * 60;
162 seconds += date->tm_sec;
163
b86b480f 164 return(seconds);
9af24521
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165}
166
167
554fcfb9 168#ifdef DEBUGGING
7430375d 169static int S_check_tm(struct TM *tm)
9af24521 170{
9af24521 171 /* Don't forget leap seconds */
af9b2bf5 172 assert(tm->tm_sec >= 0);
9af24521
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173 assert(tm->tm_sec <= 61);
174
af9b2bf5 175 assert(tm->tm_min >= 0);
9af24521
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176 assert(tm->tm_min <= 59);
177
178 assert(tm->tm_hour >= 0);
179 assert(tm->tm_hour <= 23);
180
181 assert(tm->tm_mday >= 1);
af9b2bf5 182 assert(tm->tm_mday <= days_in_month[IS_LEAP(tm->tm_year)][tm->tm_mon]);
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183
184 assert(tm->tm_mon >= 0);
185 assert(tm->tm_mon <= 11);
186
187 assert(tm->tm_wday >= 0);
188 assert(tm->tm_wday <= 6);
189
190 assert(tm->tm_yday >= 0);
af9b2bf5 191 assert(tm->tm_yday <= length_of_year[IS_LEAP(tm->tm_year)]);
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192
193#ifdef HAS_TM_TM_GMTOFF
194 assert(tm->tm_gmtoff >= -24 * 60 * 60);
195 assert(tm->tm_gmtoff <= 24 * 60 * 60);
196#endif
af9b2bf5
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197
198 return 1;
a272e669 199}
554fcfb9 200#endif
a64acb40 201
a272e669
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202
203/* The exceptional centuries without leap years cause the cycle to
204 shift by 16
205*/
7430375d 206static Year S_cycle_offset(Year year)
a272e669 207{
750c447b
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208 const Year start_year = 2000;
209 Year year_diff = year - start_year;
210 Year exceptions;
003c3b95
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211
212 if( year > start_year )
213 year_diff--;
214
750c447b
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215 exceptions = year_diff / 100;
216 exceptions -= year_diff / 400;
a272e669 217
7430375d 218 TIME64_TRACE3("# year: %lld, exceptions: %lld, year_diff: %lld\n",
461d5a49 219 year, exceptions, year_diff);
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220
221 return exceptions * 16;
222}
223
224/* For a given year after 2038, pick the latest possible matching
225 year in the 28 year calendar cycle.
ea722b76
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226
227 A matching year...
228 1) Starts on the same day of the week.
229 2) Has the same leap year status.
230
231 This is so the calendars match up.
232
233 Also the previous year must match. When doing Jan 1st you might
234 wind up on Dec 31st the previous year when doing a -UTC time zone.
003c3b95
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235
236 Finally, the next year must have the same start day of week. This
237 is for Dec 31st with a +UTC time zone.
238 It doesn't need the same leap year status since we only care about
239 January 1st.
a272e669 240*/
7430375d 241static int S_safe_year(Year year)
a272e669
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242{
243 int safe_year;
7430375d 244 Year year_cycle = year + S_cycle_offset(year);
a272e669
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245
246 /* Change non-leap xx00 years to an equivalent */
7430375d 247 if( S_is_exception_century(year) )
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248 year_cycle += 11;
249
003c3b95 250 /* Also xx01 years, since the previous year will be wrong */
7430375d 251 if( S_is_exception_century(year - 1) )
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252 year_cycle += 17;
253
a272e669 254 year_cycle %= SOLAR_CYCLE_LENGTH;
ea722b76
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255 if( year_cycle < 0 )
256 year_cycle = SOLAR_CYCLE_LENGTH + year_cycle;
a272e669 257
003c3b95
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258 assert( year_cycle >= 0 );
259 assert( year_cycle < SOLAR_CYCLE_LENGTH );
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260 safe_year = safe_years[year_cycle];
261
262 assert(safe_year <= 2037 && safe_year >= 2010);
263
7430375d 264 TIME64_TRACE3("# year: %lld, year_cycle: %lld, safe_year: %d\n",
461d5a49 265 year, year_cycle, safe_year);
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266
267 return safe_year;
268}
269
750c447b 270
7430375d 271static void S_copy_little_tm_to_big_TM(const struct tm *src, struct TM *dest) {
606599e1
AD
272 assert(src);
273 assert(dest);
55971e21
DD
274#ifdef USE_TM64
275 dest->tm_sec = src->tm_sec;
276 dest->tm_min = src->tm_min;
277 dest->tm_hour = src->tm_hour;
278 dest->tm_mday = src->tm_mday;
279 dest->tm_mon = src->tm_mon;
280 dest->tm_year = (Year)src->tm_year;
281 dest->tm_wday = src->tm_wday;
282 dest->tm_yday = src->tm_yday;
283 dest->tm_isdst = src->tm_isdst;
284
285# ifdef HAS_TM_TM_GMTOFF
286 dest->tm_gmtoff = src->tm_gmtoff;
287# endif
288
289# ifdef HAS_TM_TM_ZONE
290 dest->tm_zone = src->tm_zone;
291# endif
292
293#else
294 /* They're the same type */
295 memcpy(dest, src, sizeof(*dest));
296#endif
806a119a
MS
297}
298
299
7430375d 300#ifndef HAS_LOCALTIME_R
948ea7a9 301/* Simulate localtime_r() to the best of our ability */
7430375d 302static struct tm * S_localtime_r(const time_t *clock, struct tm *result) {
c97ab489
CB
303#ifdef __VMS
304 dTHX; /* the following is defined as Perl_my_localtime(aTHX_ ...) */
dbf7dff6 305#endif
948ea7a9
MS
306 const struct tm *static_result = localtime(clock);
307
308 assert(result != NULL);
309
310 if( static_result == NULL ) {
311 memset(result, 0, sizeof(*result));
312 return NULL;
313 }
314 else {
315 memcpy(result, static_result, sizeof(*result));
316 return result;
317 }
318}
7430375d 319#endif
948ea7a9 320
7430375d 321#ifndef HAS_GMTIME_R
948ea7a9 322/* Simulate gmtime_r() to the best of our ability */
7430375d 323static struct tm * S_gmtime_r(const time_t *clock, struct tm *result) {
c97ab489
CB
324#ifdef __VMS
325 dTHX; /* the following is defined as Perl_my_localtime(aTHX_ ...) */
326#endif
948ea7a9
MS
327 const struct tm *static_result = gmtime(clock);
328
329 assert(result != NULL);
330
331 if( static_result == NULL ) {
332 memset(result, 0, sizeof(*result));
333 return NULL;
334 }
335 else {
336 memcpy(result, static_result, sizeof(*result));
337 return result;
338 }
339}
7430375d 340#endif
948ea7a9 341
7430375d 342static struct TM *S_gmtime64_r (const Time64_T *in_time, struct TM *p)
a272e669
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343{
344 int v_tm_sec, v_tm_min, v_tm_hour, v_tm_mon, v_tm_wday;
b86b480f 345 Time64_T v_tm_tday;
a272e669 346 int leap;
b86b480f 347 Time64_T m;
a272e669 348 Time64_T time = *in_time;
750c447b 349 Year year = 70;
806a119a 350 int cycles = 0;
a272e669 351
948ea7a9
MS
352 assert(p != NULL);
353
a64acb40
MS
354 /* Use the system gmtime() if time_t is small enough */
355 if( SHOULD_USE_SYSTEM_GMTIME(*in_time) ) {
cd1759d8 356 time_t safe_time = (time_t)*in_time;
806a119a
MS
357 struct tm safe_date;
358 GMTIME_R(&safe_time, &safe_date);
359
7430375d
CB
360 S_copy_little_tm_to_big_TM(&safe_date, p);
361 assert(S_check_tm(p));
806a119a 362
a64acb40
MS
363 return p;
364 }
365
9af24521 366#ifdef HAS_TM_TM_GMTOFF
a272e669
MS
367 p->tm_gmtoff = 0;
368#endif
369 p->tm_isdst = 0;
370
9af24521 371#ifdef HAS_TM_TM_ZONE
1cefca6b 372 p->tm_zone = (char *)"UTC";
a272e669
MS
373#endif
374
d95a2ea5
CB
375 v_tm_sec = (int)fmod(time, 60.0);
376 time = time >= 0 ? floor(time / 60.0) : ceil(time / 60.0);
377 v_tm_min = (int)fmod(time, 60.0);
378 time = time >= 0 ? floor(time / 60.0) : ceil(time / 60.0);
379 v_tm_hour = (int)fmod(time, 24.0);
380 time = time >= 0 ? floor(time / 24.0) : ceil(time / 24.0);
455f2c6c 381 v_tm_tday = time;
750c447b 382
a272e669
MS
383 WRAP (v_tm_sec, v_tm_min, 60);
384 WRAP (v_tm_min, v_tm_hour, 60);
385 WRAP (v_tm_hour, v_tm_tday, 24);
750c447b 386
d95a2ea5 387 v_tm_wday = (int)fmod((v_tm_tday + 4.0), 7.0);
750c447b 388 if (v_tm_wday < 0)
a272e669
MS
389 v_tm_wday += 7;
390 m = v_tm_tday;
a272e669 391
9af24521
MS
392 if (m >= CHEAT_DAYS) {
393 year = CHEAT_YEARS;
394 m -= CHEAT_DAYS;
395 }
396
397 if (m >= 0) {
a272e669 398 /* Gregorian cycles, this is huge optimization for distant times */
d95a2ea5 399 cycles = (int)floor(m / (Time64_T) days_in_gregorian_cycle);
806a119a
MS
400 if( cycles ) {
401 m -= (cycles * (Time64_T) days_in_gregorian_cycle);
402 year += (cycles * years_in_gregorian_cycle);
a272e669
MS
403 }
404
405 /* Years */
406 leap = IS_LEAP (year);
407 while (m >= (Time64_T) length_of_year[leap]) {
408 m -= (Time64_T) length_of_year[leap];
409 year++;
410 leap = IS_LEAP (year);
411 }
412
413 /* Months */
414 v_tm_mon = 0;
415 while (m >= (Time64_T) days_in_month[leap][v_tm_mon]) {
416 m -= (Time64_T) days_in_month[leap][v_tm_mon];
417 v_tm_mon++;
418 }
419 } else {
9af24521 420 year--;
a272e669
MS
421
422 /* Gregorian cycles */
d95a2ea5 423 cycles = (int)ceil((m / (Time64_T) days_in_gregorian_cycle) + 1);
806a119a
MS
424 if( cycles ) {
425 m -= (cycles * (Time64_T) days_in_gregorian_cycle);
426 year += (cycles * years_in_gregorian_cycle);
a272e669
MS
427 }
428
429 /* Years */
430 leap = IS_LEAP (year);
431 while (m < (Time64_T) -length_of_year[leap]) {
432 m += (Time64_T) length_of_year[leap];
433 year--;
434 leap = IS_LEAP (year);
435 }
436
437 /* Months */
438 v_tm_mon = 11;
439 while (m < (Time64_T) -days_in_month[leap][v_tm_mon]) {
440 m += (Time64_T) days_in_month[leap][v_tm_mon];
441 v_tm_mon--;
442 }
443 m += (Time64_T) days_in_month[leap][v_tm_mon];
444 }
445
446 p->tm_year = year;
447 if( p->tm_year != year ) {
9af24521 448#ifdef EOVERFLOW
a272e669 449 errno = EOVERFLOW;
9af24521 450#endif
a272e669
MS
451 return NULL;
452 }
453
b86b480f 454 /* At this point m is less than a year so casting to an int is safe */
a272e669 455 p->tm_mday = (int) m + 1;
b86b480f
MS
456 p->tm_yday = julian_days_by_month[leap][v_tm_mon] + (int)m;
457 p->tm_sec = v_tm_sec;
458 p->tm_min = v_tm_min;
459 p->tm_hour = v_tm_hour;
460 p->tm_mon = v_tm_mon;
461 p->tm_wday = v_tm_wday;
a272e669 462
7430375d 463 assert(S_check_tm(p));
a272e669
MS
464
465 return p;
466}
467
468
673062a9 469static struct TM *S_localtime64_r (const Time64_T *time, struct TM *local_tm)
a272e669
MS
470{
471 time_t safe_time;
806a119a
MS
472 struct tm safe_date;
473 struct TM gm_tm;
750c447b 474 Year orig_year;
a272e669
MS
475 int month_diff;
476
948ea7a9
MS
477 assert(local_tm != NULL);
478
a64acb40
MS
479 /* Use the system localtime() if time_t is small enough */
480 if( SHOULD_USE_SYSTEM_LOCALTIME(*time) ) {
cd1759d8 481 safe_time = (time_t)*time;
806a119a 482
7430375d 483 TIME64_TRACE1("Using system localtime for %lld\n", *time);
461d5a49 484
806a119a
MS
485 LOCALTIME_R(&safe_time, &safe_date);
486
7430375d
CB
487 S_copy_little_tm_to_big_TM(&safe_date, local_tm);
488 assert(S_check_tm(local_tm));
806a119a 489
a64acb40
MS
490 return local_tm;
491 }
492
7430375d
CB
493 if( S_gmtime64_r(time, &gm_tm) == NULL ) {
494 TIME64_TRACE1("gmtime64_r returned null for %lld\n", *time);
af832814 495 return NULL;
461d5a49 496 }
af832814 497
a272e669
MS
498 orig_year = gm_tm.tm_year;
499
c07fe26c 500 if (gm_tm.tm_year > (2037 - 1900) ||
461d5a49 501 gm_tm.tm_year < (1970 - 1900)
c07fe26c
MS
502 )
503 {
7430375d
CB
504 TIME64_TRACE1("Mapping tm_year %lld to safe_year\n", (Year)gm_tm.tm_year);
505 gm_tm.tm_year = S_safe_year((Year)(gm_tm.tm_year + 1900)) - 1900;
c07fe26c 506 }
a272e669 507
7430375d 508 safe_time = (time_t)S_timegm64(&gm_tm);
461d5a49 509 if( LOCALTIME_R(&safe_time, &safe_date) == NULL ) {
7430375d 510 TIME64_TRACE1("localtime_r(%d) returned NULL\n", (int)safe_time);
af832814 511 return NULL;
461d5a49 512 }
a272e669 513
7430375d 514 S_copy_little_tm_to_big_TM(&safe_date, local_tm);
806a119a 515
a272e669 516 local_tm->tm_year = orig_year;
af832814 517 if( local_tm->tm_year != orig_year ) {
7430375d 518 TIME64_TRACE2("tm_year overflow: tm_year %lld, orig_year %lld\n",
461d5a49
MS
519 (Year)local_tm->tm_year, (Year)orig_year);
520
af832814
MS
521#ifdef EOVERFLOW
522 errno = EOVERFLOW;
523#endif
524 return NULL;
525 }
526
527
a272e669
MS
528 month_diff = local_tm->tm_mon - gm_tm.tm_mon;
529
530 /* When localtime is Dec 31st previous year and
531 gmtime is Jan 1st next year.
532 */
533 if( month_diff == 11 ) {
534 local_tm->tm_year--;
535 }
536
537 /* When localtime is Jan 1st, next year and
538 gmtime is Dec 31st, previous year.
539 */
540 if( month_diff == -11 ) {
541 local_tm->tm_year++;
542 }
543
544 /* GMT is Jan 1st, xx01 year, but localtime is still Dec 31st
545 in a non-leap xx00. There is one point in the cycle
546 we can't account for which the safe xx00 year is a leap
486ec47a 547 year. So we need to correct for Dec 31st coming out as
a272e669
MS
548 the 366th day of the year.
549 */
550 if( !IS_LEAP(local_tm->tm_year) && local_tm->tm_yday == 365 )
551 local_tm->tm_yday--;
552
7430375d 553 assert(S_check_tm(local_tm));
a272e669
MS
554
555 return local_tm;
556}