1/* Convert a 'struct tm' to a time_t value.
2 Copyright (C) 1993-2017 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Paul Eggert <eggert@twinsun.com>.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <http://www.gnu.org/licenses/>. */
19
20/* Define this to have a standalone program to test this implementation of
21 mktime. */
22/* #define DEBUG_MKTIME 1 */
23
24#ifndef _LIBC
25# include <config.h>
26#endif
27
28/* Assume that leap seconds are possible, unless told otherwise.
29 If the host has a 'zic' command with a '-L leapsecondfilename' option,
30 then it supports leap seconds; otherwise it probably doesn't. */
31#ifndef LEAP_SECONDS_POSSIBLE
32# define LEAP_SECONDS_POSSIBLE 1
33#endif
34
35#include <time.h>
36
37#include <limits.h>
38
39#include <string.h> /* For the real memcpy prototype. */
40
41#if defined DEBUG_MKTIME && DEBUG_MKTIME
42# include <stdio.h>
43# include <stdlib.h>
44/* Make it work even if the system's libc has its own mktime routine. */
45# undef mktime
46# define mktime my_mktime
47#endif /* DEBUG_MKTIME */
48
49/* Some of the code in this file assumes that signed integer overflow
50 silently wraps around. This assumption can't easily be programmed
51 around, nor can it be checked for portably at compile-time or
52 easily eliminated at run-time.
53
54 Define WRAPV to 1 if the assumption is valid and if
55 #pragma GCC optimize ("wrapv")
56 does not trigger GCC bug 51793
57 <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51793>.
58 Otherwise, define it to 0; this forces the use of slower code that,
59 while not guaranteed by the C Standard, works on all production
60 platforms that we know about. */
61#ifndef WRAPV
62# if (((__GNUC__ == 4 && 4 <= __GNUC_MINOR__) || 4 < __GNUC__) \
63 && defined __GLIBC__)
64# pragma GCC optimize ("wrapv")
65# define WRAPV 1
66# else
67# define WRAPV 0
68# endif
69#endif
70
71/* Verify a requirement at compile-time (unlike assert, which is runtime). */
72#define verify(name, assertion) struct name { char a[(assertion) ? 1 : -1]; }
73
74/* A signed type that is at least one bit wider than int. */
75#if INT_MAX <= LONG_MAX / 2
76typedef long int long_int;
77#else
78typedef long long int long_int;
79#endif
80verify (long_int_is_wide_enough, INT_MAX == INT_MAX * (long_int) 2 / 2);
81
82/* Shift A right by B bits portably, by dividing A by 2**B and
83 truncating towards minus infinity. A and B should be free of side
84 effects, and B should be in the range 0 <= B <= INT_BITS - 2, where
85 INT_BITS is the number of useful bits in an int. GNU code can
86 assume that INT_BITS is at least 32.
87
88 ISO C99 says that A >> B is implementation-defined if A < 0. Some
89 implementations (e.g., UNICOS 9.0 on a Cray Y-MP EL) don't shift
90 right in the usual way when A < 0, so SHR falls back on division if
91 ordinary A >> B doesn't seem to be the usual signed shift. */
92#define SHR(a, b) \
93 ((-1 >> 1 == -1 \
94 && (long_int) -1 >> 1 == -1 \
95 && ((time_t) -1 >> 1 == -1 || ! TYPE_SIGNED (time_t))) \
96 ? (a) >> (b) \
97 : (a) / (1 << (b)) - ((a) % (1 << (b)) < 0))
98
99/* The extra casts in the following macros work around compiler bugs,
100 e.g., in Cray C 5.0.3.0. */
101
102/* True if the arithmetic type T is an integer type. bool counts as
103 an integer. */
104#define TYPE_IS_INTEGER(t) ((t) 1.5 == 1)
105
106/* True if negative values of the signed integer type T use two's
107 complement, or if T is an unsigned integer type. */
108#define TYPE_TWOS_COMPLEMENT(t) ((t) ~ (t) 0 == (t) -1)
109
110/* True if the arithmetic type T is signed. */
111#define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
112
113/* The maximum and minimum values for the integer type T. These
114 macros have undefined behavior if T is signed and has padding bits.
115 If this is a problem for you, please let us know how to fix it for
116 your host. */
117#define TYPE_MINIMUM(t) \
118 ((t) (! TYPE_SIGNED (t) \
119 ? (t) 0 \
120 : ~ TYPE_MAXIMUM (t)))
121#define TYPE_MAXIMUM(t) \
122 ((t) (! TYPE_SIGNED (t) \
123 ? (t) -1 \
124 : ((((t) 1 << (sizeof (t) * CHAR_BIT - 2)) - 1) * 2 + 1)))
125
126#ifndef TIME_T_MIN
127# define TIME_T_MIN TYPE_MINIMUM (time_t)
128#endif
129#ifndef TIME_T_MAX
130# define TIME_T_MAX TYPE_MAXIMUM (time_t)
131#endif
132#define TIME_T_MIDPOINT (SHR (TIME_T_MIN + TIME_T_MAX, 1) + 1)
133
134verify (time_t_is_integer, TYPE_IS_INTEGER (time_t));
135verify (twos_complement_arithmetic,
136 (TYPE_TWOS_COMPLEMENT (int)
137 && TYPE_TWOS_COMPLEMENT (long_int)
138 && TYPE_TWOS_COMPLEMENT (time_t)));
139
140#define EPOCH_YEAR 1970
141#define TM_YEAR_BASE 1900
142verify (base_year_is_a_multiple_of_100, TM_YEAR_BASE % 100 == 0);
143
144/* Return 1 if YEAR + TM_YEAR_BASE is a leap year. */
145static int
146leapyear (long_int year)
147{
148 /* Don't add YEAR to TM_YEAR_BASE, as that might overflow.
149 Also, work even if YEAR is negative. */
150 return
151 ((year & 3) == 0
152 && (year % 100 != 0
153 || ((year / 100) & 3) == (- (TM_YEAR_BASE / 100) & 3)));
154}
155
156/* How many days come before each month (0-12). */
157#ifndef _LIBC
158static
159#endif
160const unsigned short int __mon_yday[2][13] =
161 {
162 /* Normal years. */
163 { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 },
164 /* Leap years. */
165 { 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 }
166 };
167
168
169#ifndef _LIBC
170/* Portable standalone applications should supply a <time.h> that
171 declares a POSIX-compliant localtime_r, for the benefit of older
172 implementations that lack localtime_r or have a nonstandard one.
173 See the gnulib time_r module for one way to implement this. */
174# undef __localtime_r
175# define __localtime_r localtime_r
176# define __mktime_internal mktime_internal
177# include "mktime-internal.h"
178#endif
179
180/* Return 1 if the values A and B differ according to the rules for
181 tm_isdst: A and B differ if one is zero and the other positive. */
182static int
183isdst_differ (int a, int b)
184{
185 return (!a != !b) && (0 <= a) && (0 <= b);
186}
187
188/* Return an integer value measuring (YEAR1-YDAY1 HOUR1:MIN1:SEC1) -
189 (YEAR0-YDAY0 HOUR0:MIN0:SEC0) in seconds, assuming that the clocks
190 were not adjusted between the time stamps.
191
192 The YEAR values uses the same numbering as TP->tm_year. Values
193 need not be in the usual range. However, YEAR1 must not be less
194 than 2 * INT_MIN or greater than 2 * INT_MAX.
195
196 The result may overflow. It is the caller's responsibility to
197 detect overflow. */
198
199static time_t
200ydhms_diff (long_int year1, long_int yday1, int hour1, int min1, int sec1,
201 int year0, int yday0, int hour0, int min0, int sec0)
202{
203 verify (C99_integer_division, -1 / 2 == 0);
204
205 /* Compute intervening leap days correctly even if year is negative.
206 Take care to avoid integer overflow here. */
207 int a4 = SHR (year1, 2) + SHR (TM_YEAR_BASE, 2) - ! (year1 & 3);
208 int b4 = SHR (year0, 2) + SHR (TM_YEAR_BASE, 2) - ! (year0 & 3);
209 int a100 = a4 / 25 - (a4 % 25 < 0);
210 int b100 = b4 / 25 - (b4 % 25 < 0);
211 int a400 = SHR (a100, 2);
212 int b400 = SHR (b100, 2);
213 int intervening_leap_days = (a4 - b4) - (a100 - b100) + (a400 - b400);
214
215 /* Compute the desired time in time_t precision. Overflow might
216 occur here. */
217 time_t tyear1 = year1;
218 time_t years = tyear1 - year0;
219 time_t days = 365 * years + yday1 - yday0 + intervening_leap_days;
220 time_t hours = 24 * days + hour1 - hour0;
221 time_t minutes = 60 * hours + min1 - min0;
222 time_t seconds = 60 * minutes + sec1 - sec0;
223 return seconds;
224}
225
226/* Return the average of A and B, even if A + B would overflow. */
227static time_t
228time_t_avg (time_t a, time_t b)
229{
230 return SHR (a, 1) + SHR (b, 1) + (a & b & 1);
231}
232
233/* Return 1 if A + B does not overflow. If time_t is unsigned and if
234 B's top bit is set, assume that the sum represents A - -B, and
235 return 1 if the subtraction does not wrap around. */
236static int
237time_t_add_ok (time_t a, time_t b)
238{
239 if (! TYPE_SIGNED (time_t))
240 {
241 time_t sum = a + b;
242 return (sum < a) == (TIME_T_MIDPOINT <= b);
243 }
244 else if (WRAPV)
245 {
246 time_t sum = a + b;
247 return (sum < a) == (b < 0);
248 }
249 else
250 {
251 time_t avg = time_t_avg (a, b);
252 return TIME_T_MIN / 2 <= avg && avg <= TIME_T_MAX / 2;
253 }
254}
255
256/* Return 1 if A + B does not overflow. */
257static int
258time_t_int_add_ok (time_t a, int b)
259{
260 verify (int_no_wider_than_time_t, INT_MAX <= TIME_T_MAX);
261 if (WRAPV)
262 {
263 time_t sum = a + b;
264 return (sum < a) == (b < 0);
265 }
266 else
267 {
268 int a_odd = a & 1;
269 time_t avg = SHR (a, 1) + (SHR (b, 1) + (a_odd & b));
270 return TIME_T_MIN / 2 <= avg && avg <= TIME_T_MAX / 2;
271 }
272}
273
274/* Return a time_t value corresponding to (YEAR-YDAY HOUR:MIN:SEC),
275 assuming that *T corresponds to *TP and that no clock adjustments
276 occurred between *TP and the desired time.
277 If TP is null, return a value not equal to *T; this avoids false matches.
278 If overflow occurs, yield the minimal or maximal value, except do not
279 yield a value equal to *T. */
280static time_t
281guess_time_tm (long_int year, long_int yday, int hour, int min, int sec,
282 const time_t *t, const struct tm *tp)
283{
284 if (tp)
285 {
286 time_t d = ydhms_diff (year, yday, hour, min, sec,
287 tp->tm_year, tp->tm_yday,
288 tp->tm_hour, tp->tm_min, tp->tm_sec);
289 if (time_t_add_ok (*t, d))
290 return *t + d;
291 }
292
293 /* Overflow occurred one way or another. Return the nearest result
294 that is actually in range, except don't report a zero difference
295 if the actual difference is nonzero, as that would cause a false
296 match; and don't oscillate between two values, as that would
297 confuse the spring-forward gap detector. */
298 return (*t < TIME_T_MIDPOINT
299 ? (*t <= TIME_T_MIN + 1 ? *t + 1 : TIME_T_MIN)
300 : (TIME_T_MAX - 1 <= *t ? *t - 1 : TIME_T_MAX));
301}
302
303/* Use CONVERT to convert *T to a broken down time in *TP.
304 If *T is out of range for conversion, adjust it so that
305 it is the nearest in-range value and then convert that. */
306static struct tm *
307ranged_convert (struct tm *(*convert) (const time_t *, struct tm *),
308 time_t *t, struct tm *tp)
309{
310 struct tm *r = convert (t, tp);
311
312 if (!r && *t)
313 {
314 time_t bad = *t;
315 time_t ok = 0;
316
317 /* BAD is a known unconvertible time_t, and OK is a known good one.
318 Use binary search to narrow the range between BAD and OK until
319 they differ by 1. */
320 while (bad != ok + (bad < 0 ? -1 : 1))
321 {
322 time_t mid = *t = time_t_avg (ok, bad);
323 r = convert (t, tp);
324 if (r)
325 ok = mid;
326 else
327 bad = mid;
328 }
329
330 if (!r && ok)
331 {
332 /* The last conversion attempt failed;
333 revert to the most recent successful attempt. */
334 *t = ok;
335 r = convert (t, tp);
336 }
337 }
338
339 return r;
340}
341
342
343/* Convert *TP to a time_t value, inverting
344 the monotonic and mostly-unit-linear conversion function CONVERT.
345 Use *OFFSET to keep track of a guess at the offset of the result,
346 compared to what the result would be for UTC without leap seconds.
347 If *OFFSET's guess is correct, only one CONVERT call is needed.
348 This function is external because it is used also by timegm.c. */
349time_t
350__mktime_internal (struct tm *tp,
351 struct tm *(*convert) (const time_t *, struct tm *),
352 time_t *offset)
353{
354 time_t t, gt, t0, t1, t2;
355 struct tm tm;
356
357 /* The maximum number of probes (calls to CONVERT) should be enough
358 to handle any combinations of time zone rule changes, solar time,
359 leap seconds, and oscillations around a spring-forward gap.
360 POSIX.1 prohibits leap seconds, but some hosts have them anyway. */
361 int remaining_probes = 6;
362
363 /* Time requested. Copy it in case CONVERT modifies *TP; this can
364 occur if TP is localtime's returned value and CONVERT is localtime. */
365 int sec = tp->tm_sec;
366 int min = tp->tm_min;
367 int hour = tp->tm_hour;
368 int mday = tp->tm_mday;
369 int mon = tp->tm_mon;
370 int year_requested = tp->tm_year;
371 int isdst = tp->tm_isdst;
372
373 /* 1 if the previous probe was DST. */
374 int dst2;
375
376 /* Ensure that mon is in range, and set year accordingly. */
377 int mon_remainder = mon % 12;
378 int negative_mon_remainder = mon_remainder < 0;
379 int mon_years = mon / 12 - negative_mon_remainder;
380 long_int lyear_requested = year_requested;
381 long_int year = lyear_requested + mon_years;
382
383 /* The other values need not be in range:
384 the remaining code handles minor overflows correctly,
385 assuming int and time_t arithmetic wraps around.
386 Major overflows are caught at the end. */
387
388 /* Calculate day of year from year, month, and day of month.
389 The result need not be in range. */
390 int mon_yday = ((__mon_yday[leapyear (year)]
391 [mon_remainder + 12 * negative_mon_remainder])
392 - 1);
393 long_int lmday = mday;
394 long_int yday = mon_yday + lmday;
395
396 time_t guessed_offset = *offset;
397
398 int sec_requested = sec;
399
400 if (LEAP_SECONDS_POSSIBLE)
401 {
402 /* Handle out-of-range seconds specially,
403 since ydhms_tm_diff assumes every minute has 60 seconds. */
404 if (sec < 0)
405 sec = 0;
406 if (59 < sec)
407 sec = 59;
408 }
409
410 /* Invert CONVERT by probing. First assume the same offset as last
411 time. */
412
413 t0 = ydhms_diff (year, yday, hour, min, sec,
414 EPOCH_YEAR - TM_YEAR_BASE, 0, 0, 0, - guessed_offset);
415
416 if (TIME_T_MAX / INT_MAX / 366 / 24 / 60 / 60 < 3)
417 {
418 /* time_t isn't large enough to rule out overflows, so check
419 for major overflows. A gross check suffices, since if t0
420 has overflowed, it is off by a multiple of TIME_T_MAX -
421 TIME_T_MIN + 1. So ignore any component of the difference
422 that is bounded by a small value. */
423
424 /* Approximate log base 2 of the number of time units per
425 biennium. A biennium is 2 years; use this unit instead of
426 years to avoid integer overflow. For example, 2 average
427 Gregorian years are 2 * 365.2425 * 24 * 60 * 60 seconds,
428 which is 63113904 seconds, and rint (log2 (63113904)) is
429 26. */
430 int ALOG2_SECONDS_PER_BIENNIUM = 26;
431 int ALOG2_MINUTES_PER_BIENNIUM = 20;
432 int ALOG2_HOURS_PER_BIENNIUM = 14;
433 int ALOG2_DAYS_PER_BIENNIUM = 10;
434 int LOG2_YEARS_PER_BIENNIUM = 1;
435
436 int approx_requested_biennia =
437 (SHR (year_requested, LOG2_YEARS_PER_BIENNIUM)
438 - SHR (EPOCH_YEAR - TM_YEAR_BASE, LOG2_YEARS_PER_BIENNIUM)
439 + SHR (mday, ALOG2_DAYS_PER_BIENNIUM)
440 + SHR (hour, ALOG2_HOURS_PER_BIENNIUM)
441 + SHR (min, ALOG2_MINUTES_PER_BIENNIUM)
442 + (LEAP_SECONDS_POSSIBLE
443 ? 0
444 : SHR (sec, ALOG2_SECONDS_PER_BIENNIUM)));
445
446 int approx_biennia = SHR (t0, ALOG2_SECONDS_PER_BIENNIUM);
447 int diff = approx_biennia - approx_requested_biennia;
448 int approx_abs_diff = diff < 0 ? -1 - diff : diff;
449
450 /* IRIX 4.0.5 cc miscalculates TIME_T_MIN / 3: it erroneously
451 gives a positive value of 715827882. Setting a variable
452 first then doing math on it seems to work.
453 (ghazi@caip.rutgers.edu) */
454 time_t time_t_max = TIME_T_MAX;
455 time_t time_t_min = TIME_T_MIN;
456 time_t overflow_threshold =
457 (time_t_max / 3 - time_t_min / 3) >> ALOG2_SECONDS_PER_BIENNIUM;
458
459 if (overflow_threshold < approx_abs_diff)
460 {
461 /* Overflow occurred. Try repairing it; this might work if
462 the time zone offset is enough to undo the overflow. */
463 time_t repaired_t0 = -1 - t0;
464 approx_biennia = SHR (repaired_t0, ALOG2_SECONDS_PER_BIENNIUM);
465 diff = approx_biennia - approx_requested_biennia;
466 approx_abs_diff = diff < 0 ? -1 - diff : diff;
467 if (overflow_threshold < approx_abs_diff)
468 return -1;
469 guessed_offset += repaired_t0 - t0;
470 t0 = repaired_t0;
471 }
472 }
473
474 /* Repeatedly use the error to improve the guess. */
475
476 for (t = t1 = t2 = t0, dst2 = 0;
477 (gt = guess_time_tm (year, yday, hour, min, sec, &t,
478 ranged_convert (convert, &t, &tm)),
479 t != gt);
480 t1 = t2, t2 = t, t = gt, dst2 = tm.tm_isdst != 0)
481 if (t == t1 && t != t2
482 && (tm.tm_isdst < 0
483 || (isdst < 0
484 ? dst2 <= (tm.tm_isdst != 0)
485 : (isdst != 0) != (tm.tm_isdst != 0))))
486 /* We can't possibly find a match, as we are oscillating
487 between two values. The requested time probably falls
488 within a spring-forward gap of size GT - T. Follow the common
489 practice in this case, which is to return a time that is GT - T
490 away from the requested time, preferring a time whose
491 tm_isdst differs from the requested value. (If no tm_isdst
492 was requested and only one of the two values has a nonzero
493 tm_isdst, prefer that value.) In practice, this is more
494 useful than returning -1. */
495 goto offset_found;
496 else if (--remaining_probes == 0)
497 return -1;
498
499 /* We have a match. Check whether tm.tm_isdst has the requested
500 value, if any. */
501 if (isdst_differ (isdst, tm.tm_isdst))
502 {
503 /* tm.tm_isdst has the wrong value. Look for a neighboring
504 time with the right value, and use its UTC offset.
505
506 Heuristic: probe the adjacent timestamps in both directions,
507 looking for the desired isdst. This should work for all real
508 time zone histories in the tz database. */
509
510 /* Distance between probes when looking for a DST boundary. In
511 tzdata2003a, the shortest period of DST is 601200 seconds
512 (e.g., America/Recife starting 2000-10-08 01:00), and the
513 shortest period of non-DST surrounded by DST is 694800
514 seconds (Africa/Tunis starting 1943-04-17 01:00). Use the
515 minimum of these two values, so we don't miss these short
516 periods when probing. */
517 int stride = 601200;
518
519 /* The longest period of DST in tzdata2003a is 536454000 seconds
520 (e.g., America/Jujuy starting 1946-10-01 01:00). The longest
521 period of non-DST is much longer, but it makes no real sense
522 to search for more than a year of non-DST, so use the DST
523 max. */
524 int duration_max = 536454000;
525
526 /* Search in both directions, so the maximum distance is half
527 the duration; add the stride to avoid off-by-1 problems. */
528 int delta_bound = duration_max / 2 + stride;
529
530 int delta, direction;
531
532 for (delta = stride; delta < delta_bound; delta += stride)
533 for (direction = -1; direction <= 1; direction += 2)
534 if (time_t_int_add_ok (t, delta * direction))
535 {
536 time_t ot = t + delta * direction;
537 struct tm otm;
538 ranged_convert (convert, &ot, &otm);
539 if (! isdst_differ (isdst, otm.tm_isdst))
540 {
541 /* We found the desired tm_isdst.
542 Extrapolate back to the desired time. */
543 t = guess_time_tm (year, yday, hour, min, sec, &ot, &otm);
544 ranged_convert (convert, &t, &tm);
545 goto offset_found;
546 }
547 }
548 }
549
550 offset_found:
551 *offset = guessed_offset + t - t0;
552
553 if (LEAP_SECONDS_POSSIBLE && sec_requested != tm.tm_sec)
554 {
555 /* Adjust time to reflect the tm_sec requested, not the normalized value.
556 Also, repair any damage from a false match due to a leap second. */
557 int sec_adjustment = (sec == 0 && tm.tm_sec == 60) - sec;
558 if (! time_t_int_add_ok (t, sec_requested))
559 return -1;
560 t1 = t + sec_requested;
561 if (! time_t_int_add_ok (t1, sec_adjustment))
562 return -1;
563 t2 = t1 + sec_adjustment;
564 if (! convert (&t2, &tm))
565 return -1;
566 t = t2;
567 }
568
569 *tp = tm;
570 return t;
571}
572
573
574/* FIXME: This should use a signed type wide enough to hold any UTC
575 offset in seconds. 'int' should be good enough for GNU code. We
576 can't fix this unilaterally though, as other modules invoke
577 __mktime_internal. */
578static time_t localtime_offset;
579
580/* Convert *TP to a time_t value. */
581time_t
582mktime (struct tm *tp)
583{
584#ifdef _LIBC
585 /* POSIX.1 8.1.1 requires that whenever mktime() is called, the
586 time zone names contained in the external variable 'tzname' shall
587 be set as if the tzset() function had been called. */
588 __tzset ();
589#endif
590
591 return __mktime_internal (tp, __localtime_r, &localtime_offset);
592}
593
594#ifdef weak_alias
595weak_alias (mktime, timelocal)
596#endif
597
598#ifdef _LIBC
599libc_hidden_def (mktime)
600libc_hidden_weak (timelocal)
601#endif
602
603#if defined DEBUG_MKTIME && DEBUG_MKTIME
604
605static int
606not_equal_tm (const struct tm *a, const struct tm *b)
607{
608 return ((a->tm_sec ^ b->tm_sec)
609 | (a->tm_min ^ b->tm_min)
610 | (a->tm_hour ^ b->tm_hour)
611 | (a->tm_mday ^ b->tm_mday)
612 | (a->tm_mon ^ b->tm_mon)
613 | (a->tm_year ^ b->tm_year)
614 | (a->tm_yday ^ b->tm_yday)
615 | isdst_differ (a->tm_isdst, b->tm_isdst));
616}
617
618static void
619print_tm (const struct tm *tp)
620{
621 if (tp)
622 printf ("%04d-%02d-%02d %02d:%02d:%02d yday %03d wday %d isdst %d",
623 tp->tm_year + TM_YEAR_BASE, tp->tm_mon + 1, tp->tm_mday,
624 tp->tm_hour, tp->tm_min, tp->tm_sec,
625 tp->tm_yday, tp->tm_wday, tp->tm_isdst);
626 else
627 printf ("0");
628}
629
630static int
631check_result (time_t tk, struct tm tmk, time_t tl, const struct tm *lt)
632{
633 if (tk != tl || !lt || not_equal_tm (&tmk, lt))
634 {
635 printf ("mktime (");
636 print_tm (lt);
637 printf (")\nyields (");
638 print_tm (&tmk);
639 printf (") == %ld, should be %ld\n", (long int) tk, (long int) tl);
640 return 1;
641 }
642
643 return 0;
644}
645
646int
647main (int argc, char **argv)
648{
649 int status = 0;
650 struct tm tm, tmk, tml;
651 struct tm *lt;
652 time_t tk, tl, tl1;
653 char trailer;
654
655 if ((argc == 3 || argc == 4)
656 && (sscanf (argv[1], "%d-%d-%d%c",
657 &tm.tm_year, &tm.tm_mon, &tm.tm_mday, &trailer)
658 == 3)
659 && (sscanf (argv[2], "%d:%d:%d%c",
660 &tm.tm_hour, &tm.tm_min, &tm.tm_sec, &trailer)
661 == 3))
662 {
663 tm.tm_year -= TM_YEAR_BASE;
664 tm.tm_mon--;
665 tm.tm_isdst = argc == 3 ? -1 : atoi (argv[3]);
666 tmk = tm;
667 tl = mktime (&tmk);
668 lt = localtime (&tl);
669 if (lt)
670 {
671 tml = *lt;
672 lt = &tml;
673 }
674 printf ("mktime returns %ld == ", (long int) tl);
675 print_tm (&tmk);
676 printf ("\n");
677 status = check_result (tl, tmk, tl, lt);
678 }
679 else if (argc == 4 || (argc == 5 && strcmp (argv[4], "-") == 0))
680 {
681 time_t from = atol (argv[1]);
682 time_t by = atol (argv[2]);
683 time_t to = atol (argv[3]);
684
685 if (argc == 4)
686 for (tl = from; by < 0 ? to <= tl : tl <= to; tl = tl1)
687 {
688 lt = localtime (&tl);
689 if (lt)
690 {
691 tmk = tml = *lt;
692 tk = mktime (&tmk);
693 status |= check_result (tk, tmk, tl, &tml);
694 }
695 else
696 {
697 printf ("localtime (%ld) yields 0\n", (long int) tl);
698 status = 1;
699 }
700 tl1 = tl + by;
701 if ((tl1 < tl) != (by < 0))
702 break;
703 }
704 else
705 for (tl = from; by < 0 ? to <= tl : tl <= to; tl = tl1)
706 {
707 /* Null benchmark. */
708 lt = localtime (&tl);
709 if (lt)
710 {
711 tmk = tml = *lt;
712 tk = tl;
713 status |= check_result (tk, tmk, tl, &tml);
714 }
715 else
716 {
717 printf ("localtime (%ld) yields 0\n", (long int) tl);
718 status = 1;
719 }
720 tl1 = tl + by;
721 if ((tl1 < tl) != (by < 0))
722 break;
723 }
724 }
725 else
726 printf ("Usage:\
727\t%s YYYY-MM-DD HH:MM:SS [ISDST] # Test given time.\n\
728\t%s FROM BY TO # Test values FROM, FROM+BY, ..., TO.\n\
729\t%s FROM BY TO - # Do not test those values (for benchmark).\n",
730 argv[0], argv[0], argv[0]);
731
732 return status;
733}
734
735#endif /* DEBUG_MKTIME */
736
737/*
738Local Variables:
739compile-command: "gcc -DDEBUG_MKTIME -I. -Wall -W -O2 -g mktime.c -o mktime"
740End:
741*/
742