1 /*
2 * The MIT License (MIT)
3 *
4 * Copyright (c) 2015-2019 Derick Rethans
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22 * THE SOFTWARE.
23 */
24
25 #include "timelib.h"
26 #include "timelib_private.h"
27
28 /* jan feb mrt apr may jun jul aug sep oct nov dec */
29 static int month_tab_leap[12] = { -1, 30, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
30 static int month_tab[12] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
31
32 /* dec jan feb mrt apr may jun jul aug sep oct nov dec */
33 static int days_in_month_leap[13] = { 31, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
34 static int days_in_month[13] = { 31, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
35
do_range_limit(timelib_sll start,timelib_sll end,timelib_sll adj,timelib_sll * a,timelib_sll * b)36 static void do_range_limit(timelib_sll start, timelib_sll end, timelib_sll adj, timelib_sll *a, timelib_sll *b)
37 {
38 if (*a < start) {
39 *b -= (start - *a - 1) / adj + 1;
40 *a += adj * ((start - *a - 1) / adj + 1);
41 }
42 if (*a >= end) {
43 *b += *a / adj;
44 *a -= adj * (*a / adj);
45 }
46 }
47
inc_month(timelib_sll * y,timelib_sll * m)48 static void inc_month(timelib_sll *y, timelib_sll *m)
49 {
50 (*m)++;
51 if (*m > 12) {
52 *m -= 12;
53 (*y)++;
54 }
55 }
56
dec_month(timelib_sll * y,timelib_sll * m)57 static void dec_month(timelib_sll *y, timelib_sll *m)
58 {
59 (*m)--;
60 if (*m < 1) {
61 *m += 12;
62 (*y)--;
63 }
64 }
65
do_range_limit_days_relative(timelib_sll * base_y,timelib_sll * base_m,timelib_sll * y,timelib_sll * m,timelib_sll * d,timelib_sll invert)66 static void do_range_limit_days_relative(timelib_sll *base_y, timelib_sll *base_m, timelib_sll *y, timelib_sll *m, timelib_sll *d, timelib_sll invert)
67 {
68 timelib_sll leapyear;
69 timelib_sll month, year;
70 timelib_sll days;
71
72 do_range_limit(1, 13, 12, base_m, base_y);
73
74 year = *base_y;
75 month = *base_m;
76
77 /*
78 printf( "S: Y%d M%d %d %d %d %d\n", year, month, *y, *m, *d, days);
79 */
80 if (!invert) {
81 while (*d < 0) {
82 dec_month(&year, &month);
83 leapyear = timelib_is_leap(year);
84 days = leapyear ? days_in_month_leap[month] : days_in_month[month];
85
86 /* printf( "I Y%d M%d %d %d %d %d\n", year, month, *y, *m, *d, days); */
87
88 *d += days;
89 (*m)--;
90 }
91 } else {
92 while (*d < 0) {
93 leapyear = timelib_is_leap(year);
94 days = leapyear ? days_in_month_leap[month] : days_in_month[month];
95
96 /* printf( "I Y%d M%d %d %d %d %d\n", year, month, *y, *m, *d, days); */
97
98 *d += days;
99 (*m)--;
100 inc_month(&year, &month);
101 }
102 }
103 /*
104 printf( "E: Y%d M%d %d %d %d %d\n", year, month, *y, *m, *d, days);
105 */
106 }
107
do_range_limit_days(timelib_sll * y,timelib_sll * m,timelib_sll * d)108 static int do_range_limit_days(timelib_sll *y, timelib_sll *m, timelib_sll *d)
109 {
110 timelib_sll leapyear;
111 timelib_sll days_this_month;
112 timelib_sll last_month, last_year;
113 timelib_sll days_last_month;
114
115 /* can jump an entire leap year period quickly */
116 if (*d >= DAYS_PER_LYEAR_PERIOD || *d <= -DAYS_PER_LYEAR_PERIOD) {
117 *y += YEARS_PER_LYEAR_PERIOD * (*d / DAYS_PER_LYEAR_PERIOD);
118 *d -= DAYS_PER_LYEAR_PERIOD * (*d / DAYS_PER_LYEAR_PERIOD);
119 }
120
121 do_range_limit(1, 13, 12, m, y);
122
123 leapyear = timelib_is_leap(*y);
124 days_this_month = leapyear ? days_in_month_leap[*m] : days_in_month[*m];
125 last_month = (*m) - 1;
126
127 if (last_month < 1) {
128 last_month += 12;
129 last_year = (*y) - 1;
130 } else {
131 last_year = (*y);
132 }
133 leapyear = timelib_is_leap(last_year);
134 days_last_month = leapyear ? days_in_month_leap[last_month] : days_in_month[last_month];
135
136 if (*d <= 0) {
137 *d += days_last_month;
138 (*m)--;
139 return 1;
140 }
141 if (*d > days_this_month) {
142 *d -= days_this_month;
143 (*m)++;
144 return 1;
145 }
146 return 0;
147 }
148
do_adjust_for_weekday(timelib_time * time)149 static void do_adjust_for_weekday(timelib_time* time)
150 {
151 timelib_sll current_dow, difference;
152
153 current_dow = timelib_day_of_week(time->y, time->m, time->d);
154 if (time->relative.weekday_behavior == 2)
155 {
156 /* To make "this week" work, where the current DOW is a "sunday" */
157 if (current_dow == 0 && time->relative.weekday != 0) {
158 time->relative.weekday -= 7;
159 }
160
161 /* To make "sunday this week" work, where the current DOW is not a
162 * "sunday" */
163 if (time->relative.weekday == 0 && current_dow != 0) {
164 time->relative.weekday = 7;
165 }
166
167 time->d -= current_dow;
168 time->d += time->relative.weekday;
169 return;
170 }
171 difference = time->relative.weekday - current_dow;
172 if ((time->relative.d < 0 && difference < 0) || (time->relative.d >= 0 && difference <= -time->relative.weekday_behavior)) {
173 difference += 7;
174 }
175 if (time->relative.weekday >= 0) {
176 time->d += difference;
177 } else {
178 time->d -= (7 - (abs(time->relative.weekday) - current_dow));
179 }
180 time->relative.have_weekday_relative = 0;
181 }
182
timelib_do_rel_normalize(timelib_time * base,timelib_rel_time * rt)183 void timelib_do_rel_normalize(timelib_time *base, timelib_rel_time *rt)
184 {
185 do_range_limit(0, 1000000, 1000000, &rt->us, &rt->s);
186 do_range_limit(0, 60, 60, &rt->s, &rt->i);
187 do_range_limit(0, 60, 60, &rt->i, &rt->h);
188 do_range_limit(0, 24, 24, &rt->h, &rt->d);
189 do_range_limit(0, 12, 12, &rt->m, &rt->y);
190
191 do_range_limit_days_relative(&base->y, &base->m, &rt->y, &rt->m, &rt->d, rt->invert);
192 do_range_limit(0, 12, 12, &rt->m, &rt->y);
193 }
194
195 #define EPOCH_DAY 719468
196
magic_date_calc(timelib_time * time)197 static void magic_date_calc(timelib_time *time)
198 {
199 timelib_sll y, ddd, mi, mm, dd, g;
200
201 /* The algorithm doesn't work before the year 1 */
202 if (time->d < -719498) {
203 return;
204 }
205
206 g = time->d + EPOCH_DAY - 1;
207
208 y = (10000 * g + 14780) / 3652425;
209 ddd = g - ((365*y) + (y/4) - (y/100) + (y/400));
210 if (ddd < 0) {
211 y--;
212 ddd = g - ((365*y) + (y/4) - (y/100) + (y/400));
213 }
214 mi = (100 * ddd + 52) / 3060;
215 mm = ((mi + 2) % 12) + 1;
216 y = y + (mi + 2) / 12;
217 dd = ddd - ((mi * 306 + 5) / 10) + 1;
218 time->y = y;
219 time->m = mm;
220 time->d = dd;
221 }
222
timelib_do_normalize(timelib_time * time)223 void timelib_do_normalize(timelib_time* time)
224 {
225 if (time->us != TIMELIB_UNSET) do_range_limit(0, 1000000, 1000000, &time->us, &time->s);
226 if (time->s != TIMELIB_UNSET) do_range_limit(0, 60, 60, &time->s, &time->i);
227 if (time->s != TIMELIB_UNSET) do_range_limit(0, 60, 60, &time->i, &time->h);
228 if (time->s != TIMELIB_UNSET) do_range_limit(0, 24, 24, &time->h, &time->d);
229 do_range_limit(1, 13, 12, &time->m, &time->y);
230
231 /* Short cut if we're doing things against the Epoch */
232 if (time->y == 1970 && time->m == 1 && time->d != 1) {
233 magic_date_calc(time);
234 }
235
236 do {} while (do_range_limit_days(&time->y, &time->m, &time->d));
237 do_range_limit(1, 13, 12, &time->m, &time->y);
238 }
239
do_adjust_relative(timelib_time * time)240 static void do_adjust_relative(timelib_time* time)
241 {
242 if (time->relative.have_weekday_relative) {
243 do_adjust_for_weekday(time);
244 }
245 timelib_do_normalize(time);
246
247 if (time->have_relative) {
248 time->us += time->relative.us;
249
250 time->s += time->relative.s;
251 time->i += time->relative.i;
252 time->h += time->relative.h;
253
254 time->d += time->relative.d;
255 time->m += time->relative.m;
256 time->y += time->relative.y;
257 }
258
259 switch (time->relative.first_last_day_of) {
260 case TIMELIB_SPECIAL_FIRST_DAY_OF_MONTH: /* first */
261 time->d = 1;
262 break;
263 case TIMELIB_SPECIAL_LAST_DAY_OF_MONTH: /* last */
264 time->d = 0;
265 time->m++;
266 break;
267 }
268
269 timelib_do_normalize(time);
270 }
271
do_adjust_special_weekday(timelib_time * time)272 static void do_adjust_special_weekday(timelib_time* time)
273 {
274 timelib_sll count, dow, rem;
275
276 count = time->relative.special.amount;
277 dow = timelib_day_of_week(time->y, time->m, time->d);
278
279 /* Add increments of 5 weekdays as a week, leaving the DOW unchanged. */
280 time->d += (count / 5) * 7;
281
282 /* Deal with the remainder. */
283 rem = (count % 5);
284
285 if (count > 0) {
286 if (rem == 0) {
287 /* Head back to Friday if we stop on the weekend. */
288 if (dow == 0) {
289 time->d -= 2;
290 } else if (dow == 6) {
291 time->d -= 1;
292 }
293 } else if (dow == 6) {
294 /* We ended up on Saturday, but there's still work to do, so move
295 * to Sunday and continue from there. */
296 time->d += 1;
297 } else if (dow + rem > 5) {
298 /* We're on a weekday, but we're going past Friday, so skip right
299 * over the weekend. */
300 time->d += 2;
301 }
302 } else {
303 /* Completely mirror the forward direction. This also covers the 0
304 * case, since if we start on the weekend, we want to move forward as
305 * if we stopped there while going backwards. */
306 if (rem == 0) {
307 if (dow == 6) {
308 time->d += 2;
309 } else if (dow == 0) {
310 time->d += 1;
311 }
312 } else if (dow == 0) {
313 time->d -= 1;
314 } else if (dow + rem < 1) {
315 time->d -= 2;
316 }
317 }
318
319 time->d += rem;
320 }
321
do_adjust_special(timelib_time * time)322 static void do_adjust_special(timelib_time* time)
323 {
324 if (time->relative.have_special_relative) {
325 switch (time->relative.special.type) {
326 case TIMELIB_SPECIAL_WEEKDAY:
327 do_adjust_special_weekday(time);
328 break;
329 }
330 }
331 timelib_do_normalize(time);
332 memset(&(time->relative.special), 0, sizeof(time->relative.special));
333 }
334
do_adjust_special_early(timelib_time * time)335 static void do_adjust_special_early(timelib_time* time)
336 {
337 if (time->relative.have_special_relative) {
338 switch (time->relative.special.type) {
339 case TIMELIB_SPECIAL_DAY_OF_WEEK_IN_MONTH:
340 time->d = 1;
341 time->m += time->relative.m;
342 time->relative.m = 0;
343 break;
344 case TIMELIB_SPECIAL_LAST_DAY_OF_WEEK_IN_MONTH:
345 time->d = 1;
346 time->m += time->relative.m + 1;
347 time->relative.m = 0;
348 break;
349 }
350 }
351 switch (time->relative.first_last_day_of) {
352 case TIMELIB_SPECIAL_FIRST_DAY_OF_MONTH: /* first */
353 time->d = 1;
354 break;
355 case TIMELIB_SPECIAL_LAST_DAY_OF_MONTH: /* last */
356 time->d = 0;
357 time->m++;
358 break;
359 }
360 timelib_do_normalize(time);
361 }
362
do_years(timelib_sll year)363 static timelib_sll do_years(timelib_sll year)
364 {
365 timelib_sll i;
366 timelib_sll res = 0;
367 timelib_sll eras;
368
369 eras = (year - 1970) / 40000;
370
371 /* Hack to make sure we don't overflow. Right now, we can't easily thrown a
372 * warning in this case, so we'll just return some rubbish. Sucks, but at
373 * least it doesn't show UBSAN warnings anymore */
374 if (eras < -1000000 || eras > 1000000) {
375 return eras > 0 ? LLONG_MAX/10 : LLONG_MIN/10;
376 }
377
378 if (eras != 0) {
379 year = year - (eras * 40000);
380 res += (SECS_PER_ERA * eras * 100);
381 }
382
383 if (year >= 1970) {
384 for (i = year - 1; i >= 1970; i--) {
385 if (timelib_is_leap(i)) {
386 res += (DAYS_PER_LYEAR * SECS_PER_DAY);
387 } else {
388 res += (DAYS_PER_YEAR * SECS_PER_DAY);
389 }
390 }
391 } else {
392 for (i = 1969; i >= year; i--) {
393 if (timelib_is_leap(i)) {
394 res -= (DAYS_PER_LYEAR * SECS_PER_DAY);
395 } else {
396 res -= (DAYS_PER_YEAR * SECS_PER_DAY);
397 }
398 }
399 }
400 return res;
401 }
402
do_months(timelib_ull month,timelib_sll year)403 static timelib_sll do_months(timelib_ull month, timelib_sll year)
404 {
405 if (timelib_is_leap(year)) {
406 return ((month_tab_leap[month - 1] + 1) * SECS_PER_DAY);
407 } else {
408 return ((month_tab[month - 1]) * SECS_PER_DAY);
409 }
410 }
411
do_days(timelib_ull day)412 static timelib_sll do_days(timelib_ull day)
413 {
414 return ((day - 1) * SECS_PER_DAY);
415 }
416
do_time(timelib_ull hour,timelib_ull minute,timelib_ull second)417 static timelib_sll do_time(timelib_ull hour, timelib_ull minute, timelib_ull second)
418 {
419 timelib_sll res = 0;
420
421 res += hour * 3600;
422 res += minute * 60;
423 res += second;
424 return res;
425 }
426
do_adjust_timezone(timelib_time * tz,timelib_tzinfo * tzi)427 static timelib_sll do_adjust_timezone(timelib_time *tz, timelib_tzinfo *tzi)
428 {
429 switch (tz->zone_type) {
430 case TIMELIB_ZONETYPE_OFFSET:
431
432 tz->is_localtime = 1;
433 return -tz->z;
434 break;
435
436 case TIMELIB_ZONETYPE_ABBR: {
437 timelib_sll tmp;
438
439 tz->is_localtime = 1;
440 tmp = -tz->z;
441 tmp -= tz->dst * 3600;
442 return tmp;
443 }
444 break;
445
446 case TIMELIB_ZONETYPE_ID:
447 tzi = tz->tz_info;
448 /* Break intentionally missing */
449
450 default:
451 /* No timezone in struct, fallback to reference if possible */
452 if (tzi) {
453 timelib_time_offset *before, *after;
454 timelib_sll tmp;
455 int in_transition;
456
457 tz->is_localtime = 1;
458 before = timelib_get_time_zone_info(tz->sse, tzi);
459 after = timelib_get_time_zone_info(tz->sse - before->offset, tzi);
460 timelib_set_timezone(tz, tzi);
461
462 in_transition = (
463 ((tz->sse - after->offset) >= (after->transition_time + (before->offset - after->offset))) &&
464 ((tz->sse - after->offset) < after->transition_time)
465 );
466
467 if ((before->offset != after->offset) && !in_transition) {
468 tmp = -after->offset;
469 } else {
470 tmp = -tz->z;
471 }
472 timelib_time_offset_dtor(before);
473 timelib_time_offset_dtor(after);
474
475 {
476 timelib_time_offset *gmt_offset;
477
478 gmt_offset = timelib_get_time_zone_info(tz->sse + tmp, tzi);
479 tz->z = gmt_offset->offset;
480
481 tz->dst = gmt_offset->is_dst;
482 if (tz->tz_abbr) {
483 timelib_free(tz->tz_abbr);
484 }
485 tz->tz_abbr = timelib_strdup(gmt_offset->abbr);
486 timelib_time_offset_dtor(gmt_offset);
487 }
488 return tmp;
489 }
490 }
491 return 0;
492 }
493
timelib_update_ts(timelib_time * time,timelib_tzinfo * tzi)494 void timelib_update_ts(timelib_time* time, timelib_tzinfo* tzi)
495 {
496 timelib_sll res = 0;
497
498 do_adjust_special_early(time);
499 do_adjust_relative(time);
500 do_adjust_special(time);
501 res += do_years(time->y);
502 res += do_months(time->m, time->y);
503 res += do_days(time->d);
504 res += do_time(time->h, time->i, time->s);
505 time->sse = res;
506
507 res += do_adjust_timezone(time, tzi);
508 time->sse = res;
509
510 time->sse_uptodate = 1;
511 time->have_relative = time->relative.have_weekday_relative = time->relative.have_special_relative = time->relative.first_last_day_of = 0;
512 }
513
514 #if 0
515 int main(void)
516 {
517 timelib_sll res;
518 timelib_time time;
519
520 time = timelib_strtotime("10 Feb 2005 06:07:03 PM CET"); /* 1108055223 */
521 printf ("%04d-%02d-%02d %02d:%02d:%02d.%-5d %+04d %1d",
522 time.y, time.m, time.d, time.h, time.i, time.s, time.f, time.z, time.dst);
523 if (time.have_relative) {
524 printf ("%3dY %3dM %3dD / %3dH %3dM %3dS",
525 time.relative.y, time.relative.m, time.relative.d, time.relative.h, time.relative.i, time.relative.s);
526 }
527 if (time.have_weekday_relative) {
528 printf (" / %d", time.relative.weekday);
529 }
530 res = time2unixtime(&time);
531 printf("%Ld\n", res);
532
533 return 0;
534 }
535 #endif
536
