Commit | Line | Data |
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a272e669 MS |
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 | ||
7430375d | 36 | S_localtime64_r() is a 64-bit equivalent of localtime_r(). |
a272e669 | 37 | |
7430375d | 38 | S_gmtime64_r() is a 64-bit equivalent of gmtime_r(). |
a272e669 MS |
39 | |
40 | */ | |
41 | ||
7643e68f | 42 | #include "time64.h" |
af9b2bf5 | 43 | |
4bb2f1fc | 44 | static const char days_in_month[2][12] = { |
a272e669 MS |
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 | 49 | static const short julian_days_by_month[2][12] = { |
a272e669 MS |
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 | 54 | static const short length_of_year[2] = { 365, 366 }; |
a272e669 MS |
55 | |
56 | /* Number of days in a 400 year Gregorian cycle */ | |
806a119a | 57 | static const Year years_in_gregorian_cycle = 400; |
a272e669 MS |
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 |
4bb2f1fc | 62 | static const short safe_years[SOLAR_CYCLE_LENGTH] = { |
a272e669 MS |
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 | 72 | static const char dow_year_start[SOLAR_CYCLE_LENGTH] = { |
003c3b95 MS |
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 MS |
80 | }; |
81 | ||
9af24521 MS |
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 MS |
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 MS |
93 | #ifdef USE_SYSTEM_LOCALTIME |
94 | # define SHOULD_USE_SYSTEM_LOCALTIME(a) ( \ | |
7bda3dfc MS |
95 | (a) <= SYSTEM_LOCALTIME_MAX && \ |
96 | (a) >= SYSTEM_LOCALTIME_MIN \ | |
97 | ) | |
b86b480f MS |
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 MS |
104 | (a) <= SYSTEM_GMTIME_MAX && \ |
105 | (a) >= SYSTEM_GMTIME_MIN \ | |
106 | ) | |
b86b480f MS |
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 |
7430375d CB |
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 | 124 | static int S_is_exception_century(Year year) |
a272e669 MS |
125 | { |
126 | int is_exception = ((year % 100 == 0) && !(year % 400 == 0)); | |
7430375d | 127 | TIME64_TRACE1("# is_exception_century: %s\n", is_exception ? "yes" : "no"); |
a272e669 MS |
128 | |
129 | return(is_exception); | |
130 | } | |
131 | ||
9af24521 | 132 | |
7430375d | 133 | static Time64_T S_timegm64(struct TM *date) { |
b86b480f MS |
134 | int days = 0; |
135 | Time64_T seconds = 0; | |
136 | Year year; | |
a272e669 | 137 | |
9af24521 MS |
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 MS |
143 | } |
144 | } | |
9af24521 MS |
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 MS |
160 | seconds += date->tm_hour * 60 * 60; |
161 | seconds += date->tm_min * 60; | |
162 | seconds += date->tm_sec; | |
163 | ||
b86b480f | 164 | return(seconds); |
9af24521 MS |
165 | } |
166 | ||
167 | ||
554fcfb9 | 168 | #ifdef DEBUGGING |
7430375d | 169 | static int S_check_tm(struct TM *tm) |
9af24521 | 170 | { |
9af24521 | 171 | /* Don't forget leap seconds */ |
af9b2bf5 | 172 | assert(tm->tm_sec >= 0); |
9af24521 MS |
173 | assert(tm->tm_sec <= 61); |
174 | ||
af9b2bf5 | 175 | assert(tm->tm_min >= 0); |
9af24521 MS |
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 MS |
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 MS |
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 MS |
197 | |
198 | return 1; | |
a272e669 | 199 | } |
554fcfb9 | 200 | #endif |
a64acb40 | 201 | |
a272e669 MS |
202 | |
203 | /* The exceptional centuries without leap years cause the cycle to | |
204 | shift by 16 | |
205 | */ | |
7430375d | 206 | static Year S_cycle_offset(Year year) |
a272e669 | 207 | { |
750c447b MS |
208 | const Year start_year = 2000; |
209 | Year year_diff = year - start_year; | |
210 | Year exceptions; | |
003c3b95 MS |
211 | |
212 | if( year > start_year ) | |
213 | year_diff--; | |
214 | ||
750c447b MS |
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); |
a272e669 MS |
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 MS |
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 MS |
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 | 241 | static int S_safe_year(Year year) |
a272e669 MS |
242 | { |
243 | int safe_year; | |
7430375d | 244 | Year year_cycle = year + S_cycle_offset(year); |
a272e669 MS |
245 | |
246 | /* Change non-leap xx00 years to an equivalent */ | |
7430375d | 247 | if( S_is_exception_century(year) ) |
a272e669 MS |
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) ) |
003c3b95 MS |
252 | year_cycle += 17; |
253 | ||
a272e669 | 254 | year_cycle %= SOLAR_CYCLE_LENGTH; |
ea722b76 MS |
255 | if( year_cycle < 0 ) |
256 | year_cycle = SOLAR_CYCLE_LENGTH + year_cycle; | |
a272e669 | 257 | |
003c3b95 MS |
258 | assert( year_cycle >= 0 ); |
259 | assert( year_cycle < SOLAR_CYCLE_LENGTH ); | |
a272e669 MS |
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); |
a272e669 MS |
266 | |
267 | return safe_year; | |
268 | } | |
269 | ||
750c447b | 270 | |
7430375d | 271 | static 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 | 302 | static 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 | 323 | static 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 | 342 | static struct TM *S_gmtime64_r (const Time64_T *in_time, struct TM *p) |
a272e669 MS |
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 | 469 | static 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 | } |