Commit | Line | Data |
a272e669 |
1 | /* |
2 | |
3 | Copyright (c) 2007-2008 Michael G Schwern |
4 | |
5 | This software originally derived from Paul Sheer's pivotal_gmtime_r.c. |
6 | |
7 | The MIT License: |
8 | |
9 | Permission is hereby granted, free of charge, to any person obtaining a copy |
10 | of this software and associated documentation files (the "Software"), to deal |
11 | in the Software without restriction, including without limitation the rights |
12 | to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
13 | copies of the Software, and to permit persons to whom the Software is |
14 | furnished to do so, subject to the following conditions: |
15 | |
16 | The above copyright notice and this permission notice shall be included in |
17 | all copies or substantial portions of the Software. |
18 | |
19 | THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
20 | IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
21 | FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
22 | AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
23 | LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
24 | OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
25 | THE SOFTWARE. |
26 | |
27 | */ |
28 | |
29 | /* |
30 | |
31 | Programmers who have available to them 64-bit time values as a 'long |
32 | long' type can use localtime64_r() and gmtime64_r() which correctly |
33 | converts the time even on 32-bit systems. Whether you have 64-bit time |
34 | values will depend on the operating system. |
35 | |
36 | localtime64_r() is a 64-bit equivalent of localtime_r(). |
37 | |
38 | gmtime64_r() is a 64-bit equivalent of gmtime_r(). |
39 | |
40 | */ |
41 | |
7643e68f |
42 | #include "time64.h" |
af9b2bf5 |
43 | |
a272e669 |
44 | static const int days_in_month[2][12] = { |
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 | |
49 | static const int julian_days_by_month[2][12] = { |
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 | |
54 | static const int length_of_year[2] = { 365, 366 }; |
55 | |
56 | /* Number of days in a 400 year Gregorian cycle */ |
806a119a |
57 | static const Year years_in_gregorian_cycle = 400; |
a272e669 |
58 | static 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 |
62 | static const int safe_years[SOLAR_CYCLE_LENGTH] = { |
a272e669 |
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 | |
ea722b76 |
72 | static const int dow_year_start[SOLAR_CYCLE_LENGTH] = { |
003c3b95 |
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 */ |
a272e669 |
80 | }; |
81 | |
9af24521 |
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 |
a272e669 |
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 | |
b86b480f |
93 | #ifdef USE_SYSTEM_LOCALTIME |
94 | # define SHOULD_USE_SYSTEM_LOCALTIME(a) ( \ |
7bda3dfc |
95 | (a) <= SYSTEM_LOCALTIME_MAX && \ |
96 | (a) >= SYSTEM_LOCALTIME_MIN \ |
97 | ) |
b86b480f |
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) ( \ |
7bda3dfc |
104 | (a) <= SYSTEM_GMTIME_MAX && \ |
105 | (a) >= SYSTEM_GMTIME_MIN \ |
106 | ) |
b86b480f |
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 |
d4fb0a1f |
113 | # define TRACE(format) (fprintf(stderr, format)) |
114 | # define TRACE1(format, var1) (fprintf(stderr, format, var1)) |
115 | # define TRACE2(format, var1, var2) (fprintf(stderr, format, var1, var2)) |
116 | # define TRACE3(format, var1, var2, var3) (fprintf(stderr, format, var1, var2, var3)) |
461d5a49 |
117 | #else |
d4fb0a1f |
118 | # define TRACE(format) ((void)0) |
119 | # define TRACE1(format, var1) ((void)0) |
120 | # define TRACE2(format, var1, var2) ((void)0) |
121 | # define TRACE3(format, var1, var2, var3) ((void)0) |
461d5a49 |
122 | #endif |
a64acb40 |
123 | |
b86b480f |
124 | static int is_exception_century(Year year) |
a272e669 |
125 | { |
126 | int is_exception = ((year % 100 == 0) && !(year % 400 == 0)); |
d4fb0a1f |
127 | TRACE1("# is_exception_century: %s\n", is_exception ? "yes" : "no"); |
a272e669 |
128 | |
129 | return(is_exception); |
130 | } |
131 | |
9af24521 |
132 | |
806a119a |
133 | Time64_T timegm64(struct TM *date) { |
b86b480f |
134 | int days = 0; |
135 | Time64_T seconds = 0; |
136 | Year year; |
a272e669 |
137 | |
9af24521 |
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++; |
a272e669 |
143 | } |
144 | } |
9af24521 |
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 |
156 | /* Avoid overflowing the days integer */ |
157 | seconds = days; |
158 | seconds = seconds * 60 * 60 * 24; |
159 | |
9af24521 |
160 | seconds += date->tm_hour * 60 * 60; |
161 | seconds += date->tm_min * 60; |
162 | seconds += date->tm_sec; |
163 | |
b86b480f |
164 | return(seconds); |
9af24521 |
165 | } |
166 | |
167 | |
554fcfb9 |
168 | #ifdef DEBUGGING |
806a119a |
169 | static int check_tm(struct TM *tm) |
9af24521 |
170 | { |
9af24521 |
171 | /* Don't forget leap seconds */ |
af9b2bf5 |
172 | assert(tm->tm_sec >= 0); |
9af24521 |
173 | assert(tm->tm_sec <= 61); |
174 | |
af9b2bf5 |
175 | assert(tm->tm_min >= 0); |
9af24521 |
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]); |
9af24521 |
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)]); |
9af24521 |
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 |
197 | |
198 | return 1; |
a272e669 |
199 | } |
554fcfb9 |
200 | #endif |
a64acb40 |
201 | |
a272e669 |
202 | |
203 | /* The exceptional centuries without leap years cause the cycle to |
204 | shift by 16 |
205 | */ |
806a119a |
206 | static Year cycle_offset(Year year) |
a272e669 |
207 | { |
750c447b |
208 | const Year start_year = 2000; |
209 | Year year_diff = year - start_year; |
210 | Year exceptions; |
003c3b95 |
211 | |
212 | if( year > start_year ) |
213 | year_diff--; |
214 | |
750c447b |
215 | exceptions = year_diff / 100; |
216 | exceptions -= year_diff / 400; |
a272e669 |
217 | |
d4fb0a1f |
218 | TRACE3("# year: %lld, exceptions: %lld, year_diff: %lld\n", |
461d5a49 |
219 | year, exceptions, year_diff); |
a272e669 |
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 |
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 |
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 | */ |
806a119a |
241 | static int safe_year(Year year) |
a272e669 |
242 | { |
243 | int safe_year; |
806a119a |
244 | Year year_cycle = year + cycle_offset(year); |
a272e669 |
245 | |
246 | /* Change non-leap xx00 years to an equivalent */ |
806a119a |
247 | if( is_exception_century(year) ) |
a272e669 |
248 | year_cycle += 11; |
249 | |
003c3b95 |
250 | /* Also xx01 years, since the previous year will be wrong */ |
806a119a |
251 | if( is_exception_century(year - 1) ) |
003c3b95 |
252 | year_cycle += 17; |
253 | |
a272e669 |
254 | year_cycle %= SOLAR_CYCLE_LENGTH; |
ea722b76 |
255 | if( year_cycle < 0 ) |
256 | year_cycle = SOLAR_CYCLE_LENGTH + year_cycle; |
a272e669 |
257 | |
003c3b95 |
258 | assert( year_cycle >= 0 ); |
259 | assert( year_cycle < SOLAR_CYCLE_LENGTH ); |
a272e669 |
260 | safe_year = safe_years[year_cycle]; |
261 | |
262 | assert(safe_year <= 2037 && safe_year >= 2010); |
263 | |
d4fb0a1f |
264 | TRACE3("# year: %lld, year_cycle: %lld, safe_year: %d\n", |
461d5a49 |
265 | year, year_cycle, safe_year); |
a272e669 |
266 | |
267 | return safe_year; |
268 | } |
269 | |
750c447b |
270 | |
ef3a38ff |
271 | void copy_little_tm_to_big_TM(const struct tm *src, struct TM *dest) { |
806a119a |
272 | if( src == NULL ) { |
273 | memset(dest, 0, sizeof(*dest)); |
274 | } |
275 | else { |
276 | # ifdef USE_TM64 |
277 | dest->tm_sec = src->tm_sec; |
278 | dest->tm_min = src->tm_min; |
279 | dest->tm_hour = src->tm_hour; |
280 | dest->tm_mday = src->tm_mday; |
281 | dest->tm_mon = src->tm_mon; |
282 | dest->tm_year = (Year)src->tm_year; |
283 | dest->tm_wday = src->tm_wday; |
284 | dest->tm_yday = src->tm_yday; |
285 | dest->tm_isdst = src->tm_isdst; |
286 | |
287 | # ifdef HAS_TM_TM_GMTOFF |
288 | dest->tm_gmtoff = src->tm_gmtoff; |
289 | # endif |
290 | |
291 | # ifdef HAS_TM_TM_ZONE |
292 | dest->tm_zone = src->tm_zone; |
293 | # endif |
294 | |
295 | # else |
296 | /* They're the same type */ |
297 | memcpy(dest, src, sizeof(*dest)); |
298 | # endif |
299 | } |
300 | } |
301 | |
302 | |
ef3a38ff |
303 | void copy_big_TM_to_little_tm(const struct TM *src, struct tm *dest) { |
806a119a |
304 | if( src == NULL ) { |
305 | memset(dest, 0, sizeof(*dest)); |
306 | } |
307 | else { |
308 | # ifdef USE_TM64 |
309 | dest->tm_sec = src->tm_sec; |
310 | dest->tm_min = src->tm_min; |
311 | dest->tm_hour = src->tm_hour; |
312 | dest->tm_mday = src->tm_mday; |
313 | dest->tm_mon = src->tm_mon; |
314 | dest->tm_year = (int)src->tm_year; |
315 | dest->tm_wday = src->tm_wday; |
316 | dest->tm_yday = src->tm_yday; |
317 | dest->tm_isdst = src->tm_isdst; |
318 | |
319 | # ifdef HAS_TM_TM_GMTOFF |
320 | dest->tm_gmtoff = src->tm_gmtoff; |
321 | # endif |
322 | |
323 | # ifdef HAS_TM_TM_ZONE |
324 | dest->tm_zone = src->tm_zone; |
325 | # endif |
326 | |
327 | # else |
328 | /* They're the same type */ |
329 | memcpy(dest, src, sizeof(*dest)); |
330 | # endif |
331 | } |
332 | } |
333 | |
334 | |
948ea7a9 |
335 | /* Simulate localtime_r() to the best of our ability */ |
336 | struct tm * fake_localtime_r(const time_t *clock, struct tm *result) { |
478780ab |
337 | dTHX; /* in case the following is defined as Perl_my_localtime(aTHX_ ...) */ |
948ea7a9 |
338 | const struct tm *static_result = localtime(clock); |
339 | |
340 | assert(result != NULL); |
341 | |
342 | if( static_result == NULL ) { |
343 | memset(result, 0, sizeof(*result)); |
344 | return NULL; |
345 | } |
346 | else { |
347 | memcpy(result, static_result, sizeof(*result)); |
348 | return result; |
349 | } |
350 | } |
351 | |
352 | |
353 | /* Simulate gmtime_r() to the best of our ability */ |
354 | struct tm * fake_gmtime_r(const time_t *clock, struct tm *result) { |
478780ab |
355 | dTHX; /* in case the following is defined as Perl_my_gmtime(aTHX_ ...) */ |
948ea7a9 |
356 | const struct tm *static_result = gmtime(clock); |
357 | |
358 | assert(result != NULL); |
359 | |
360 | if( static_result == NULL ) { |
361 | memset(result, 0, sizeof(*result)); |
362 | return NULL; |
363 | } |
364 | else { |
365 | memcpy(result, static_result, sizeof(*result)); |
366 | return result; |
367 | } |
368 | } |
369 | |
370 | |
806a119a |
371 | struct TM *gmtime64_r (const Time64_T *in_time, struct TM *p) |
a272e669 |
372 | { |
373 | int v_tm_sec, v_tm_min, v_tm_hour, v_tm_mon, v_tm_wday; |
b86b480f |
374 | Time64_T v_tm_tday; |
a272e669 |
375 | int leap; |
b86b480f |
376 | Time64_T m; |
a272e669 |
377 | Time64_T time = *in_time; |
750c447b |
378 | Year year = 70; |
806a119a |
379 | int cycles = 0; |
a272e669 |
380 | |
948ea7a9 |
381 | assert(p != NULL); |
382 | |
a64acb40 |
383 | /* Use the system gmtime() if time_t is small enough */ |
384 | if( SHOULD_USE_SYSTEM_GMTIME(*in_time) ) { |
cd1759d8 |
385 | time_t safe_time = (time_t)*in_time; |
806a119a |
386 | struct tm safe_date; |
387 | GMTIME_R(&safe_time, &safe_date); |
388 | |
ef3a38ff |
389 | copy_little_tm_to_big_TM(&safe_date, p); |
806a119a |
390 | assert(check_tm(p)); |
391 | |
a64acb40 |
392 | return p; |
393 | } |
394 | |
9af24521 |
395 | #ifdef HAS_TM_TM_GMTOFF |
a272e669 |
396 | p->tm_gmtoff = 0; |
397 | #endif |
398 | p->tm_isdst = 0; |
399 | |
9af24521 |
400 | #ifdef HAS_TM_TM_ZONE |
a272e669 |
401 | p->tm_zone = "UTC"; |
402 | #endif |
403 | |
750c447b |
404 | v_tm_sec = (int)(time % 60); |
a272e669 |
405 | time /= 60; |
750c447b |
406 | v_tm_min = (int)(time % 60); |
a272e669 |
407 | time /= 60; |
750c447b |
408 | v_tm_hour = (int)(time % 24); |
a272e669 |
409 | time /= 24; |
410 | v_tm_tday = time; |
750c447b |
411 | |
a272e669 |
412 | WRAP (v_tm_sec, v_tm_min, 60); |
413 | WRAP (v_tm_min, v_tm_hour, 60); |
414 | WRAP (v_tm_hour, v_tm_tday, 24); |
750c447b |
415 | |
416 | v_tm_wday = (int)((v_tm_tday + 4) % 7); |
417 | if (v_tm_wday < 0) |
a272e669 |
418 | v_tm_wday += 7; |
419 | m = v_tm_tday; |
a272e669 |
420 | |
9af24521 |
421 | if (m >= CHEAT_DAYS) { |
422 | year = CHEAT_YEARS; |
423 | m -= CHEAT_DAYS; |
424 | } |
425 | |
426 | if (m >= 0) { |
a272e669 |
427 | /* Gregorian cycles, this is huge optimization for distant times */ |
461d5a49 |
428 | cycles = (int)(m / (Time64_T) days_in_gregorian_cycle); |
806a119a |
429 | if( cycles ) { |
430 | m -= (cycles * (Time64_T) days_in_gregorian_cycle); |
431 | year += (cycles * years_in_gregorian_cycle); |
a272e669 |
432 | } |
433 | |
434 | /* Years */ |
435 | leap = IS_LEAP (year); |
436 | while (m >= (Time64_T) length_of_year[leap]) { |
437 | m -= (Time64_T) length_of_year[leap]; |
438 | year++; |
439 | leap = IS_LEAP (year); |
440 | } |
441 | |
442 | /* Months */ |
443 | v_tm_mon = 0; |
444 | while (m >= (Time64_T) days_in_month[leap][v_tm_mon]) { |
445 | m -= (Time64_T) days_in_month[leap][v_tm_mon]; |
446 | v_tm_mon++; |
447 | } |
448 | } else { |
9af24521 |
449 | year--; |
a272e669 |
450 | |
451 | /* Gregorian cycles */ |
461d5a49 |
452 | cycles = (int)((m / (Time64_T) days_in_gregorian_cycle) + 1); |
806a119a |
453 | if( cycles ) { |
454 | m -= (cycles * (Time64_T) days_in_gregorian_cycle); |
455 | year += (cycles * years_in_gregorian_cycle); |
a272e669 |
456 | } |
457 | |
458 | /* Years */ |
459 | leap = IS_LEAP (year); |
460 | while (m < (Time64_T) -length_of_year[leap]) { |
461 | m += (Time64_T) length_of_year[leap]; |
462 | year--; |
463 | leap = IS_LEAP (year); |
464 | } |
465 | |
466 | /* Months */ |
467 | v_tm_mon = 11; |
468 | while (m < (Time64_T) -days_in_month[leap][v_tm_mon]) { |
469 | m += (Time64_T) days_in_month[leap][v_tm_mon]; |
470 | v_tm_mon--; |
471 | } |
472 | m += (Time64_T) days_in_month[leap][v_tm_mon]; |
473 | } |
474 | |
475 | p->tm_year = year; |
476 | if( p->tm_year != year ) { |
9af24521 |
477 | #ifdef EOVERFLOW |
a272e669 |
478 | errno = EOVERFLOW; |
9af24521 |
479 | #endif |
a272e669 |
480 | return NULL; |
481 | } |
482 | |
b86b480f |
483 | /* At this point m is less than a year so casting to an int is safe */ |
a272e669 |
484 | p->tm_mday = (int) m + 1; |
b86b480f |
485 | p->tm_yday = julian_days_by_month[leap][v_tm_mon] + (int)m; |
486 | p->tm_sec = v_tm_sec; |
487 | p->tm_min = v_tm_min; |
488 | p->tm_hour = v_tm_hour; |
489 | p->tm_mon = v_tm_mon; |
490 | p->tm_wday = v_tm_wday; |
a272e669 |
491 | |
806a119a |
492 | assert(check_tm(p)); |
a272e669 |
493 | |
494 | return p; |
495 | } |
496 | |
497 | |
806a119a |
498 | struct TM *localtime64_r (const Time64_T *time, struct TM *local_tm) |
a272e669 |
499 | { |
500 | time_t safe_time; |
806a119a |
501 | struct tm safe_date; |
502 | struct TM gm_tm; |
750c447b |
503 | Year orig_year; |
a272e669 |
504 | int month_diff; |
505 | |
948ea7a9 |
506 | assert(local_tm != NULL); |
507 | |
a64acb40 |
508 | /* Use the system localtime() if time_t is small enough */ |
509 | if( SHOULD_USE_SYSTEM_LOCALTIME(*time) ) { |
cd1759d8 |
510 | safe_time = (time_t)*time; |
806a119a |
511 | |
d4fb0a1f |
512 | TRACE1("Using system localtime for %lld\n", *time); |
461d5a49 |
513 | |
806a119a |
514 | LOCALTIME_R(&safe_time, &safe_date); |
515 | |
ef3a38ff |
516 | copy_little_tm_to_big_TM(&safe_date, local_tm); |
806a119a |
517 | assert(check_tm(local_tm)); |
518 | |
a64acb40 |
519 | return local_tm; |
520 | } |
521 | |
461d5a49 |
522 | if( gmtime64_r(time, &gm_tm) == NULL ) { |
d4fb0a1f |
523 | TRACE1("gmtime64_r returned null for %lld\n", *time); |
af832814 |
524 | return NULL; |
461d5a49 |
525 | } |
af832814 |
526 | |
a272e669 |
527 | orig_year = gm_tm.tm_year; |
528 | |
c07fe26c |
529 | if (gm_tm.tm_year > (2037 - 1900) || |
461d5a49 |
530 | gm_tm.tm_year < (1970 - 1900) |
c07fe26c |
531 | ) |
532 | { |
d4fb0a1f |
533 | TRACE1("Mapping tm_year %lld to safe_year\n", (Year)gm_tm.tm_year); |
b86b480f |
534 | gm_tm.tm_year = safe_year((Year)(gm_tm.tm_year + 1900)) - 1900; |
c07fe26c |
535 | } |
a272e669 |
536 | |
cd1759d8 |
537 | safe_time = (time_t)timegm64(&gm_tm); |
461d5a49 |
538 | if( LOCALTIME_R(&safe_time, &safe_date) == NULL ) { |
d4fb0a1f |
539 | TRACE1("localtime_r(%d) returned NULL\n", (int)safe_time); |
af832814 |
540 | return NULL; |
461d5a49 |
541 | } |
a272e669 |
542 | |
ef3a38ff |
543 | copy_little_tm_to_big_TM(&safe_date, local_tm); |
806a119a |
544 | |
a272e669 |
545 | local_tm->tm_year = orig_year; |
af832814 |
546 | if( local_tm->tm_year != orig_year ) { |
d4fb0a1f |
547 | TRACE2("tm_year overflow: tm_year %lld, orig_year %lld\n", |
461d5a49 |
548 | (Year)local_tm->tm_year, (Year)orig_year); |
549 | |
af832814 |
550 | #ifdef EOVERFLOW |
551 | errno = EOVERFLOW; |
552 | #endif |
553 | return NULL; |
554 | } |
555 | |
556 | |
a272e669 |
557 | month_diff = local_tm->tm_mon - gm_tm.tm_mon; |
558 | |
559 | /* When localtime is Dec 31st previous year and |
560 | gmtime is Jan 1st next year. |
561 | */ |
562 | if( month_diff == 11 ) { |
563 | local_tm->tm_year--; |
564 | } |
565 | |
566 | /* When localtime is Jan 1st, next year and |
567 | gmtime is Dec 31st, previous year. |
568 | */ |
569 | if( month_diff == -11 ) { |
570 | local_tm->tm_year++; |
571 | } |
572 | |
573 | /* GMT is Jan 1st, xx01 year, but localtime is still Dec 31st |
574 | in a non-leap xx00. There is one point in the cycle |
575 | we can't account for which the safe xx00 year is a leap |
576 | year. So we need to correct for Dec 31st comming out as |
577 | the 366th day of the year. |
578 | */ |
579 | if( !IS_LEAP(local_tm->tm_year) && local_tm->tm_yday == 365 ) |
580 | local_tm->tm_yday--; |
581 | |
806a119a |
582 | assert(check_tm(local_tm)); |
a272e669 |
583 | |
584 | return local_tm; |
585 | } |