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 | ||
1477bdc1 LT |
29 | |
30 | /* | |
0f7b3448 KW |
31 | * This thing all things devours: |
32 | * Birds, beasts, trees, flowers; | |
1477bdc1 LT |
33 | * Gnaws iron, bites steel; |
34 | * Grinds hard stones to meal; | |
35 | * Slays king, ruins town, | |
36 | * And beats high mountain down." | |
37 | * | |
38 | * Poor Bilbo sat in the dark thinking of all the horrible names of all the | |
39 | * giants and ogres he had ever heard told of in tales, but not one of them had | |
40 | * done all these things. He had a feeling that the answer was quite different | |
0f7b3448 | 41 | * and that he ought to know it, but he could not think of it. He began to get |
1477bdc1 LT |
42 | * frightened, and that is bad for thinking. Gollum began to get out of his |
43 | * boat. He flapped into the water and paddled to the bank; Bilbo could see his | |
44 | * eyes coming towards him. His tongue seemed to stick in his mouth; he wanted | |
45 | * to shout out: "Give me more time! Give me time!" But all that came out with | |
46 | * a sudden squeal was: | |
47 | * | |
48 | * "Time! Time!" | |
49 | * | |
50 | * Bilbo was saved by pure luck. For that of course was the answer. | |
51 | * | |
52 | * [p.84 of _The Hobbit_: "Riddles in the Dark"] | |
53 | * | |
54 | */ | |
55 | ||
a272e669 MS |
56 | /* |
57 | ||
58 | Programmers who have available to them 64-bit time values as a 'long | |
59 | long' type can use localtime64_r() and gmtime64_r() which correctly | |
60 | converts the time even on 32-bit systems. Whether you have 64-bit time | |
61 | values will depend on the operating system. | |
62 | ||
f832b29a | 63 | Perl_localtime64_r() is a 64-bit equivalent of localtime_r(). |
a272e669 | 64 | |
f832b29a | 65 | Perl_gmtime64_r() is a 64-bit equivalent of gmtime_r(). |
a272e669 MS |
66 | |
67 | */ | |
68 | ||
f832b29a JH |
69 | #include "EXTERN.h" |
70 | #define PERL_IN_TIME64_C | |
71 | #include "perl.h" | |
7643e68f | 72 | #include "time64.h" |
af9b2bf5 | 73 | |
4bb2f1fc | 74 | static const char days_in_month[2][12] = { |
a272e669 MS |
75 | {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}, |
76 | {31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}, | |
77 | }; | |
78 | ||
4bb2f1fc | 79 | static const short julian_days_by_month[2][12] = { |
a272e669 MS |
80 | {0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334}, |
81 | {0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335}, | |
82 | }; | |
83 | ||
4bb2f1fc | 84 | static const short length_of_year[2] = { 365, 366 }; |
a272e669 MS |
85 | |
86 | /* Number of days in a 400 year Gregorian cycle */ | |
806a119a | 87 | static const Year years_in_gregorian_cycle = 400; |
a272e669 MS |
88 | static const int days_in_gregorian_cycle = (365 * 400) + 100 - 4 + 1; |
89 | ||
90 | /* 28 year calendar cycle between 2010 and 2037 */ | |
806a119a | 91 | #define SOLAR_CYCLE_LENGTH 28 |
4bb2f1fc | 92 | static const short safe_years[SOLAR_CYCLE_LENGTH] = { |
a272e669 MS |
93 | 2016, 2017, 2018, 2019, |
94 | 2020, 2021, 2022, 2023, | |
95 | 2024, 2025, 2026, 2027, | |
96 | 2028, 2029, 2030, 2031, | |
97 | 2032, 2033, 2034, 2035, | |
98 | 2036, 2037, 2010, 2011, | |
99 | 2012, 2013, 2014, 2015 | |
100 | }; | |
101 | ||
9af24521 MS |
102 | /* Let's assume people are going to be looking for dates in the future. |
103 | Let's provide some cheats so you can skip ahead. | |
104 | This has a 4x speed boost when near 2008. | |
105 | */ | |
106 | /* Number of days since epoch on Jan 1st, 2008 GMT */ | |
107 | #define CHEAT_DAYS (1199145600 / 24 / 60 / 60) | |
108 | #define CHEAT_YEARS 108 | |
a272e669 MS |
109 | |
110 | #define IS_LEAP(n) ((!(((n) + 1900) % 400) || (!(((n) + 1900) % 4) && (((n) + 1900) % 100))) != 0) | |
d584a308 | 111 | #undef WRAP /* some <termios.h> define this */ |
a272e669 MS |
112 | #define WRAP(a,b,m) ((a) = ((a) < 0 ) ? ((b)--, (a) + (m)) : (a)) |
113 | ||
b86b480f MS |
114 | #ifdef USE_SYSTEM_LOCALTIME |
115 | # define SHOULD_USE_SYSTEM_LOCALTIME(a) ( \ | |
7bda3dfc MS |
116 | (a) <= SYSTEM_LOCALTIME_MAX && \ |
117 | (a) >= SYSTEM_LOCALTIME_MIN \ | |
118 | ) | |
b86b480f MS |
119 | #else |
120 | # define SHOULD_USE_SYSTEM_LOCALTIME(a) (0) | |
121 | #endif | |
122 | ||
123 | #ifdef USE_SYSTEM_GMTIME | |
124 | # define SHOULD_USE_SYSTEM_GMTIME(a) ( \ | |
7bda3dfc MS |
125 | (a) <= SYSTEM_GMTIME_MAX && \ |
126 | (a) >= SYSTEM_GMTIME_MIN \ | |
127 | ) | |
b86b480f MS |
128 | #else |
129 | # define SHOULD_USE_SYSTEM_GMTIME(a) (0) | |
130 | #endif | |
a64acb40 | 131 | |
d4fb0a1f | 132 | /* Multi varadic macros are a C99 thing, alas */ |
461d5a49 | 133 | #ifdef TIME_64_DEBUG |
7430375d CB |
134 | # define TIME64_TRACE(format) (fprintf(stderr, format)) |
135 | # define TIME64_TRACE1(format, var1) (fprintf(stderr, format, var1)) | |
136 | # define TIME64_TRACE2(format, var1, var2) (fprintf(stderr, format, var1, var2)) | |
137 | # define TIME64_TRACE3(format, var1, var2, var3) (fprintf(stderr, format, var1, var2, var3)) | |
461d5a49 | 138 | #else |
7430375d CB |
139 | # define TIME64_TRACE(format) ((void)0) |
140 | # define TIME64_TRACE1(format, var1) ((void)0) | |
141 | # define TIME64_TRACE2(format, var1, var2) ((void)0) | |
142 | # define TIME64_TRACE3(format, var1, var2, var3) ((void)0) | |
461d5a49 | 143 | #endif |
a64acb40 | 144 | |
7430375d | 145 | static int S_is_exception_century(Year year) |
a272e669 | 146 | { |
c75442a5 | 147 | const int is_exception = ((year % 100 == 0) && !(year % 400 == 0)); |
7430375d | 148 | TIME64_TRACE1("# is_exception_century: %s\n", is_exception ? "yes" : "no"); |
a272e669 MS |
149 | |
150 | return(is_exception); | |
151 | } | |
152 | ||
9af24521 | 153 | |
c75442a5 | 154 | static Time64_T S_timegm64(const struct TM *date) { |
b86b480f MS |
155 | int days = 0; |
156 | Time64_T seconds = 0; | |
a272e669 | 157 | |
9af24521 | 158 | if( date->tm_year > 70 ) { |
c75442a5 | 159 | Year year = 70; |
9af24521 MS |
160 | while( year < date->tm_year ) { |
161 | days += length_of_year[IS_LEAP(year)]; | |
162 | year++; | |
a272e669 MS |
163 | } |
164 | } | |
9af24521 | 165 | else if ( date->tm_year < 70 ) { |
c75442a5 | 166 | Year year = 69; |
9af24521 MS |
167 | do { |
168 | days -= length_of_year[IS_LEAP(year)]; | |
169 | year--; | |
170 | } while( year >= date->tm_year ); | |
171 | } | |
172 | ||
173 | days += julian_days_by_month[IS_LEAP(date->tm_year)][date->tm_mon]; | |
174 | days += date->tm_mday - 1; | |
175 | ||
ea722b76 MS |
176 | /* Avoid overflowing the days integer */ |
177 | seconds = days; | |
178 | seconds = seconds * 60 * 60 * 24; | |
179 | ||
9af24521 MS |
180 | seconds += date->tm_hour * 60 * 60; |
181 | seconds += date->tm_min * 60; | |
182 | seconds += date->tm_sec; | |
183 | ||
b86b480f | 184 | return(seconds); |
9af24521 MS |
185 | } |
186 | ||
187 | ||
554fcfb9 | 188 | #ifdef DEBUGGING |
c75442a5 | 189 | static int S_check_tm(const struct TM *tm) |
9af24521 | 190 | { |
9af24521 | 191 | /* Don't forget leap seconds */ |
af9b2bf5 | 192 | assert(tm->tm_sec >= 0); |
9af24521 MS |
193 | assert(tm->tm_sec <= 61); |
194 | ||
af9b2bf5 | 195 | assert(tm->tm_min >= 0); |
9af24521 MS |
196 | assert(tm->tm_min <= 59); |
197 | ||
198 | assert(tm->tm_hour >= 0); | |
199 | assert(tm->tm_hour <= 23); | |
200 | ||
201 | assert(tm->tm_mday >= 1); | |
af9b2bf5 | 202 | assert(tm->tm_mday <= days_in_month[IS_LEAP(tm->tm_year)][tm->tm_mon]); |
9af24521 MS |
203 | |
204 | assert(tm->tm_mon >= 0); | |
205 | assert(tm->tm_mon <= 11); | |
206 | ||
207 | assert(tm->tm_wday >= 0); | |
208 | assert(tm->tm_wday <= 6); | |
209 | ||
210 | assert(tm->tm_yday >= 0); | |
af9b2bf5 | 211 | assert(tm->tm_yday <= length_of_year[IS_LEAP(tm->tm_year)]); |
9af24521 MS |
212 | |
213 | #ifdef HAS_TM_TM_GMTOFF | |
214 | assert(tm->tm_gmtoff >= -24 * 60 * 60); | |
215 | assert(tm->tm_gmtoff <= 24 * 60 * 60); | |
216 | #endif | |
af9b2bf5 MS |
217 | |
218 | return 1; | |
a272e669 | 219 | } |
554fcfb9 | 220 | #endif |
a64acb40 | 221 | |
a272e669 MS |
222 | |
223 | /* The exceptional centuries without leap years cause the cycle to | |
224 | shift by 16 | |
225 | */ | |
7430375d | 226 | static Year S_cycle_offset(Year year) |
a272e669 | 227 | { |
750c447b MS |
228 | const Year start_year = 2000; |
229 | Year year_diff = year - start_year; | |
230 | Year exceptions; | |
003c3b95 MS |
231 | |
232 | if( year > start_year ) | |
233 | year_diff--; | |
234 | ||
750c447b MS |
235 | exceptions = year_diff / 100; |
236 | exceptions -= year_diff / 400; | |
a272e669 | 237 | |
7430375d | 238 | TIME64_TRACE3("# year: %lld, exceptions: %lld, year_diff: %lld\n", |
461d5a49 | 239 | year, exceptions, year_diff); |
a272e669 MS |
240 | |
241 | return exceptions * 16; | |
242 | } | |
243 | ||
244 | /* For a given year after 2038, pick the latest possible matching | |
245 | year in the 28 year calendar cycle. | |
ea722b76 MS |
246 | |
247 | A matching year... | |
248 | 1) Starts on the same day of the week. | |
249 | 2) Has the same leap year status. | |
250 | ||
251 | This is so the calendars match up. | |
252 | ||
253 | Also the previous year must match. When doing Jan 1st you might | |
254 | wind up on Dec 31st the previous year when doing a -UTC time zone. | |
003c3b95 MS |
255 | |
256 | Finally, the next year must have the same start day of week. This | |
257 | is for Dec 31st with a +UTC time zone. | |
258 | It doesn't need the same leap year status since we only care about | |
259 | January 1st. | |
a272e669 | 260 | */ |
7430375d | 261 | static int S_safe_year(Year year) |
a272e669 MS |
262 | { |
263 | int safe_year; | |
7430375d | 264 | Year year_cycle = year + S_cycle_offset(year); |
a272e669 MS |
265 | |
266 | /* Change non-leap xx00 years to an equivalent */ | |
7430375d | 267 | if( S_is_exception_century(year) ) |
a272e669 MS |
268 | year_cycle += 11; |
269 | ||
003c3b95 | 270 | /* Also xx01 years, since the previous year will be wrong */ |
7430375d | 271 | if( S_is_exception_century(year - 1) ) |
003c3b95 MS |
272 | year_cycle += 17; |
273 | ||
a272e669 | 274 | year_cycle %= SOLAR_CYCLE_LENGTH; |
ea722b76 MS |
275 | if( year_cycle < 0 ) |
276 | year_cycle = SOLAR_CYCLE_LENGTH + year_cycle; | |
a272e669 | 277 | |
003c3b95 MS |
278 | assert( year_cycle >= 0 ); |
279 | assert( year_cycle < SOLAR_CYCLE_LENGTH ); | |
a272e669 MS |
280 | safe_year = safe_years[year_cycle]; |
281 | ||
282 | assert(safe_year <= 2037 && safe_year >= 2010); | |
283 | ||
7430375d | 284 | TIME64_TRACE3("# year: %lld, year_cycle: %lld, safe_year: %d\n", |
461d5a49 | 285 | year, year_cycle, safe_year); |
a272e669 MS |
286 | |
287 | return safe_year; | |
288 | } | |
289 | ||
750c447b | 290 | |
7430375d | 291 | static void S_copy_little_tm_to_big_TM(const struct tm *src, struct TM *dest) { |
606599e1 AD |
292 | assert(src); |
293 | assert(dest); | |
55971e21 DD |
294 | #ifdef USE_TM64 |
295 | dest->tm_sec = src->tm_sec; | |
296 | dest->tm_min = src->tm_min; | |
297 | dest->tm_hour = src->tm_hour; | |
298 | dest->tm_mday = src->tm_mday; | |
299 | dest->tm_mon = src->tm_mon; | |
300 | dest->tm_year = (Year)src->tm_year; | |
301 | dest->tm_wday = src->tm_wday; | |
302 | dest->tm_yday = src->tm_yday; | |
303 | dest->tm_isdst = src->tm_isdst; | |
304 | ||
305 | # ifdef HAS_TM_TM_GMTOFF | |
306 | dest->tm_gmtoff = src->tm_gmtoff; | |
307 | # endif | |
308 | ||
309 | # ifdef HAS_TM_TM_ZONE | |
310 | dest->tm_zone = src->tm_zone; | |
311 | # endif | |
312 | ||
313 | #else | |
314 | /* They're the same type */ | |
315 | memcpy(dest, src, sizeof(*dest)); | |
316 | #endif | |
806a119a MS |
317 | } |
318 | ||
f832b29a | 319 | struct TM *Perl_gmtime64_r (const Time64_T *in_time, struct TM *p) |
a272e669 MS |
320 | { |
321 | int v_tm_sec, v_tm_min, v_tm_hour, v_tm_mon, v_tm_wday; | |
b86b480f | 322 | Time64_T v_tm_tday; |
a272e669 | 323 | int leap; |
b86b480f | 324 | Time64_T m; |
a272e669 | 325 | Time64_T time = *in_time; |
750c447b | 326 | Year year = 70; |
315d3362 | 327 | dTHX; |
a272e669 | 328 | |
948ea7a9 MS |
329 | assert(p != NULL); |
330 | ||
a64acb40 MS |
331 | /* Use the system gmtime() if time_t is small enough */ |
332 | if( SHOULD_USE_SYSTEM_GMTIME(*in_time) ) { | |
cd1759d8 | 333 | time_t safe_time = (time_t)*in_time; |
806a119a | 334 | struct tm safe_date; |
315d3362 KW |
335 | struct tm * result; |
336 | ||
0e72ccea KW |
337 | GMTIME_LOCK; |
338 | ||
315d3362 KW |
339 | /* reentr.h will automatically replace this with a call to gmtime_r() |
340 | * when appropriate */ | |
341 | result = gmtime(&safe_time); | |
342 | ||
343 | assert(result != NULL); | |
344 | ||
345 | #if defined(HAS_GMTIME_R) && defined(USE_REENTRANT_API) | |
346 | ||
347 | PERL_UNUSED_VAR(safe_date); | |
348 | #else | |
349 | /* Here, no gmtime_r() and is a threaded perl where the result can be | |
350 | * overwritten by a call in another thread. Copy to a safe place, | |
0e72ccea KW |
351 | * hopefully before another gmtime that isn't using the mutexes can |
352 | * jump in and trash this result. */ | |
315d3362 KW |
353 | memcpy(&safe_date, result, sizeof(safe_date)); |
354 | result = &safe_date; | |
355 | #endif | |
0e72ccea | 356 | GMTIME_UNLOCK; |
806a119a | 357 | |
315d3362 | 358 | S_copy_little_tm_to_big_TM(result, p); |
7430375d | 359 | assert(S_check_tm(p)); |
806a119a | 360 | |
a64acb40 MS |
361 | return p; |
362 | } | |
363 | ||
9af24521 | 364 | #ifdef HAS_TM_TM_GMTOFF |
a272e669 MS |
365 | p->tm_gmtoff = 0; |
366 | #endif | |
367 | p->tm_isdst = 0; | |
368 | ||
9af24521 | 369 | #ifdef HAS_TM_TM_ZONE |
926c3ce3 | 370 | p->tm_zone = "UTC"; |
a272e669 MS |
371 | #endif |
372 | ||
42033175 JH |
373 | v_tm_sec = (int)Perl_fmod(time, 60.0); |
374 | time = time >= 0 ? Perl_floor(time / 60.0) : Perl_ceil(time / 60.0); | |
375 | v_tm_min = (int)Perl_fmod(time, 60.0); | |
376 | time = time >= 0 ? Perl_floor(time / 60.0) : Perl_ceil(time / 60.0); | |
377 | v_tm_hour = (int)Perl_fmod(time, 24.0); | |
378 | time = time >= 0 ? Perl_floor(time / 24.0) : Perl_ceil(time / 24.0); | |
455f2c6c | 379 | v_tm_tday = time; |
750c447b | 380 | |
a272e669 MS |
381 | WRAP (v_tm_sec, v_tm_min, 60); |
382 | WRAP (v_tm_min, v_tm_hour, 60); | |
383 | WRAP (v_tm_hour, v_tm_tday, 24); | |
750c447b | 384 | |
42033175 | 385 | v_tm_wday = (int)Perl_fmod((v_tm_tday + 4.0), 7.0); |
750c447b | 386 | if (v_tm_wday < 0) |
a272e669 MS |
387 | v_tm_wday += 7; |
388 | m = v_tm_tday; | |
a272e669 | 389 | |
9af24521 MS |
390 | if (m >= CHEAT_DAYS) { |
391 | year = CHEAT_YEARS; | |
392 | m -= CHEAT_DAYS; | |
393 | } | |
394 | ||
395 | if (m >= 0) { | |
a272e669 | 396 | /* Gregorian cycles, this is huge optimization for distant times */ |
c75442a5 | 397 | const int cycles = (int)Perl_floor(m / (Time64_T) days_in_gregorian_cycle); |
806a119a MS |
398 | if( cycles ) { |
399 | m -= (cycles * (Time64_T) days_in_gregorian_cycle); | |
400 | year += (cycles * years_in_gregorian_cycle); | |
a272e669 MS |
401 | } |
402 | ||
403 | /* Years */ | |
404 | leap = IS_LEAP (year); | |
405 | while (m >= (Time64_T) length_of_year[leap]) { | |
406 | m -= (Time64_T) length_of_year[leap]; | |
407 | year++; | |
408 | leap = IS_LEAP (year); | |
409 | } | |
410 | ||
411 | /* Months */ | |
412 | v_tm_mon = 0; | |
413 | while (m >= (Time64_T) days_in_month[leap][v_tm_mon]) { | |
414 | m -= (Time64_T) days_in_month[leap][v_tm_mon]; | |
415 | v_tm_mon++; | |
416 | } | |
417 | } else { | |
c75442a5 AL |
418 | int cycles; |
419 | ||
9af24521 | 420 | year--; |
a272e669 MS |
421 | |
422 | /* Gregorian cycles */ | |
42033175 | 423 | cycles = (int)Perl_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 | ||
f832b29a | 469 | struct TM *Perl_localtime64_r (const Time64_T *time, struct TM *local_tm) |
a272e669 MS |
470 | { |
471 | time_t safe_time; | |
806a119a | 472 | struct tm safe_date; |
4684bf2c | 473 | const struct tm * result; |
806a119a | 474 | struct TM gm_tm; |
153764ac | 475 | Year orig_year = 0; /* initialise to avoid spurious compiler warning */ |
a272e669 | 476 | int month_diff; |
6358af17 | 477 | const bool use_system = SHOULD_USE_SYSTEM_LOCALTIME(*time); |
4684bf2c | 478 | dTHX; |
a272e669 | 479 | |
948ea7a9 MS |
480 | assert(local_tm != NULL); |
481 | ||
a64acb40 | 482 | /* Use the system localtime() if time_t is small enough */ |
6358af17 | 483 | if (use_system) { |
cd1759d8 | 484 | safe_time = (time_t)*time; |
806a119a | 485 | |
7430375d | 486 | TIME64_TRACE1("Using system localtime for %lld\n", *time); |
a64acb40 | 487 | } |
0bd9a4dd | 488 | else { |
9b5e0ded KW |
489 | if (Perl_gmtime64_r(time, &gm_tm) == NULL) { |
490 | TIME64_TRACE1("gmtime64_r returned null for %lld\n", *time); | |
491 | return NULL; | |
492 | } | |
af832814 | 493 | |
9b5e0ded | 494 | orig_year = gm_tm.tm_year; |
a272e669 | 495 | |
9b5e0ded KW |
496 | if (gm_tm.tm_year > (2037 - 1900) || |
497 | gm_tm.tm_year < (1970 - 1900) | |
498 | ) | |
499 | { | |
500 | TIME64_TRACE1("Mapping tm_year %lld to safe_year\n", | |
501 | (Year)gm_tm.tm_year); | |
502 | gm_tm.tm_year = S_safe_year((Year)(gm_tm.tm_year + 1900)) - 1900; | |
503 | } | |
a272e669 | 504 | |
9b5e0ded | 505 | safe_time = (time_t)S_timegm64(&gm_tm); |
0bd9a4dd KW |
506 | } |
507 | ||
0e72ccea KW |
508 | LOCALTIME_LOCK; |
509 | ||
4684bf2c KW |
510 | /* reentr.h will automatically replace this with a call to localtime_r() |
511 | * when appropriate */ | |
512 | result = localtime(&safe_time); | |
513 | ||
06769212 | 514 | if(UNLIKELY(result == NULL)) { |
0e72ccea | 515 | LOCALTIME_UNLOCK; |
4684bf2c | 516 | TIME64_TRACE1("localtime(%d) returned NULL\n", (int)safe_time); |
af832814 | 517 | return NULL; |
461d5a49 | 518 | } |
a272e669 | 519 | |
4684bf2c KW |
520 | #if ! defined(USE_REENTRANT_API) || defined(PERL_REENTR_USING_LOCALTIME_R) |
521 | ||
522 | PERL_UNUSED_VAR(safe_date); | |
523 | ||
524 | #else | |
525 | ||
526 | /* Here, would be using localtime_r() if it could, meaning there isn't one, | |
527 | * and is a threaded perl where the result can be overwritten by a call in | |
528 | * another thread. Copy to a safe place, hopefully before another | |
0e72ccea KW |
529 | * localtime that isn't using the mutexes can jump in and trash this |
530 | * result. */ | |
4684bf2c KW |
531 | memcpy(&safe_date, result, sizeof(safe_date)); |
532 | result = &safe_date; | |
533 | ||
534 | #endif | |
535 | ||
0e72ccea KW |
536 | LOCALTIME_UNLOCK; |
537 | ||
4684bf2c | 538 | S_copy_little_tm_to_big_TM(result, local_tm); |
806a119a | 539 | |
0bd9a4dd KW |
540 | if (! use_system) { |
541 | ||
9b5e0ded KW |
542 | local_tm->tm_year = orig_year; |
543 | if( local_tm->tm_year != orig_year ) { | |
544 | TIME64_TRACE2("tm_year overflow: tm_year %lld, orig_year %lld\n", | |
545 | (Year)local_tm->tm_year, (Year)orig_year); | |
461d5a49 | 546 | |
af832814 | 547 | #ifdef EOVERFLOW |
9b5e0ded | 548 | errno = EOVERFLOW; |
af832814 | 549 | #endif |
9b5e0ded KW |
550 | return NULL; |
551 | } | |
af832814 | 552 | |
9b5e0ded | 553 | month_diff = local_tm->tm_mon - gm_tm.tm_mon; |
a272e669 | 554 | |
9b5e0ded KW |
555 | /* When localtime is Dec 31st previous year and |
556 | gmtime is Jan 1st next year. | |
557 | */ | |
558 | if( month_diff == 11 ) { | |
559 | local_tm->tm_year--; | |
560 | } | |
a272e669 | 561 | |
9b5e0ded KW |
562 | /* When localtime is Jan 1st, next year and |
563 | gmtime is Dec 31st, previous year. | |
564 | */ | |
565 | if( month_diff == -11 ) { | |
566 | local_tm->tm_year++; | |
567 | } | |
a272e669 | 568 | |
9b5e0ded KW |
569 | /* GMT is Jan 1st, xx01 year, but localtime is still Dec 31st |
570 | in a non-leap xx00. There is one point in the cycle | |
571 | we can't account for which the safe xx00 year is a leap | |
572 | year. So we need to correct for Dec 31st coming out as | |
573 | the 366th day of the year. | |
574 | */ | |
575 | if( !IS_LEAP(local_tm->tm_year) && local_tm->tm_yday == 365 ) | |
576 | local_tm->tm_yday--; | |
a272e669 | 577 | |
0bd9a4dd KW |
578 | } |
579 | ||
7430375d | 580 | assert(S_check_tm(local_tm)); |
a272e669 MS |
581 | |
582 | return local_tm; | |
583 | } |