source: trunk/essentials/app-arch/tar/lib/mktime.c

Last change on this file was 3342, checked in by bird, 18 years ago

tar 1.16.1

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1/* Convert a `struct tm' to a time_t value.
2 Copyright (C) 1993-1999, 2002-2005, 2006 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Paul Eggert <eggert@twinsun.com>.
5
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
9 any later version.
10
11 This program 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
14 GNU General Public License for more details.
15
16 You should have received a copy of the GNU General Public License along
17 with this program; if not, write to the Free Software Foundation,
18 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
19
20/* Define this to have a standalone program to test this implementation of
21 mktime. */
22/* #define DEBUG 1 */
23
24#ifdef HAVE_CONFIG_H
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 <sys/types.h> /* Some systems define `time_t' here. */
36#include <time.h>
37
38#include <limits.h>
39
40#include <string.h> /* For the real memcpy prototype. */
41
42#if DEBUG
43# include <stdio.h>
44# include <stdlib.h>
45/* Make it work even if the system's libc has its own mktime routine. */
46# define mktime my_mktime
47#endif /* DEBUG */
48
49/* Shift A right by B bits portably, by dividing A by 2**B and
50 truncating towards minus infinity. A and B should be free of side
51 effects, and B should be in the range 0 <= B <= INT_BITS - 2, where
52 INT_BITS is the number of useful bits in an int. GNU code can
53 assume that INT_BITS is at least 32.
54
55 ISO C99 says that A >> B is implementation-defined if A < 0. Some
56 implementations (e.g., UNICOS 9.0 on a Cray Y-MP EL) don't shift
57 right in the usual way when A < 0, so SHR falls back on division if
58 ordinary A >> B doesn't seem to be the usual signed shift. */
59#define SHR(a, b) \
60 (-1 >> 1 == -1 \
61 ? (a) >> (b) \
62 : (a) / (1 << (b)) - ((a) % (1 << (b)) < 0))
63
64/* The extra casts in the following macros work around compiler bugs,
65 e.g., in Cray C 5.0.3.0. */
66
67/* True if the arithmetic type T is an integer type. bool counts as
68 an integer. */
69#define TYPE_IS_INTEGER(t) ((t) 1.5 == 1)
70
71/* True if negative values of the signed integer type T use two's
72 complement, ones' complement, or signed magnitude representation,
73 respectively. Much GNU code assumes two's complement, but some
74 people like to be portable to all possible C hosts. */
75#define TYPE_TWOS_COMPLEMENT(t) ((t) ~ (t) 0 == (t) -1)
76#define TYPE_ONES_COMPLEMENT(t) ((t) ~ (t) 0 == 0)
77#define TYPE_SIGNED_MAGNITUDE(t) ((t) ~ (t) 0 < (t) -1)
78
79/* True if the arithmetic type T is signed. */
80#define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
81
82/* The maximum and minimum values for the integer type T. These
83 macros have undefined behavior if T is signed and has padding bits.
84 If this is a problem for you, please let us know how to fix it for
85 your host. */
86#define TYPE_MINIMUM(t) \
87 ((t) (! TYPE_SIGNED (t) \
88 ? (t) 0 \
89 : TYPE_SIGNED_MAGNITUDE (t) \
90 ? ~ (t) 0 \
91 : ~ (t) 0 << (sizeof (t) * CHAR_BIT - 1)))
92#define TYPE_MAXIMUM(t) \
93 ((t) (! TYPE_SIGNED (t) \
94 ? (t) -1 \
95 : ~ (~ (t) 0 << (sizeof (t) * CHAR_BIT - 1))))
96
97#ifndef TIME_T_MIN
98# define TIME_T_MIN TYPE_MINIMUM (time_t)
99#endif
100#ifndef TIME_T_MAX
101# define TIME_T_MAX TYPE_MAXIMUM (time_t)
102#endif
103#define TIME_T_MIDPOINT (SHR (TIME_T_MIN + TIME_T_MAX, 1) + 1)
104
105/* Verify a requirement at compile-time (unlike assert, which is runtime). */
106#define verify(name, assertion) struct name { char a[(assertion) ? 1 : -1]; }
107
108verify (time_t_is_integer, TYPE_IS_INTEGER (time_t));
109verify (twos_complement_arithmetic, TYPE_TWOS_COMPLEMENT (int));
110/* The code also assumes that signed integer overflow silently wraps
111 around, but this assumption can't be stated without causing a
112 diagnostic on some hosts. */
113
114#define EPOCH_YEAR 1970
115#define TM_YEAR_BASE 1900
116verify (base_year_is_a_multiple_of_100, TM_YEAR_BASE % 100 == 0);
117
118/* Return 1 if YEAR + TM_YEAR_BASE is a leap year. */
119static inline int
120leapyear (long int year)
121{
122 /* Don't add YEAR to TM_YEAR_BASE, as that might overflow.
123 Also, work even if YEAR is negative. */
124 return
125 ((year & 3) == 0
126 && (year % 100 != 0
127 || ((year / 100) & 3) == (- (TM_YEAR_BASE / 100) & 3)));
128}
129
130/* How many days come before each month (0-12). */
131#ifndef _LIBC
132static
133#endif
134const unsigned short int __mon_yday[2][13] =
135 {
136 /* Normal years. */
137 { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 },
138 /* Leap years. */
139 { 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 }
140 };
141
142
143#ifndef _LIBC
144/* Portable standalone applications should supply a "time_r.h" that
145 declares a POSIX-compliant localtime_r, for the benefit of older
146 implementations that lack localtime_r or have a nonstandard one.
147 See the gnulib time_r module for one way to implement this. */
148# include "time_r.h"
149# undef __localtime_r
150# define __localtime_r localtime_r
151# define __mktime_internal mktime_internal
152#endif
153
154/* Return an integer value measuring (YEAR1-YDAY1 HOUR1:MIN1:SEC1) -
155 (YEAR0-YDAY0 HOUR0:MIN0:SEC0) in seconds, assuming that the clocks
156 were not adjusted between the time stamps.
157
158 The YEAR values uses the same numbering as TP->tm_year. Values
159 need not be in the usual range. However, YEAR1 must not be less
160 than 2 * INT_MIN or greater than 2 * INT_MAX.
161
162 The result may overflow. It is the caller's responsibility to
163 detect overflow. */
164
165static inline time_t
166ydhms_diff (long int year1, long int yday1, int hour1, int min1, int sec1,
167 int year0, int yday0, int hour0, int min0, int sec0)
168{
169 verify (C99_integer_division, -1 / 2 == 0);
170 verify (long_int_year_and_yday_are_wide_enough,
171 INT_MAX <= LONG_MAX / 2 || TIME_T_MAX <= UINT_MAX);
172
173 /* Compute intervening leap days correctly even if year is negative.
174 Take care to avoid integer overflow here. */
175 int a4 = SHR (year1, 2) + SHR (TM_YEAR_BASE, 2) - ! (year1 & 3);
176 int b4 = SHR (year0, 2) + SHR (TM_YEAR_BASE, 2) - ! (year0 & 3);
177 int a100 = a4 / 25 - (a4 % 25 < 0);
178 int b100 = b4 / 25 - (b4 % 25 < 0);
179 int a400 = SHR (a100, 2);
180 int b400 = SHR (b100, 2);
181 int intervening_leap_days = (a4 - b4) - (a100 - b100) + (a400 - b400);
182
183 /* Compute the desired time in time_t precision. Overflow might
184 occur here. */
185 time_t tyear1 = year1;
186 time_t years = tyear1 - year0;
187 time_t days = 365 * years + yday1 - yday0 + intervening_leap_days;
188 time_t hours = 24 * days + hour1 - hour0;
189 time_t minutes = 60 * hours + min1 - min0;
190 time_t seconds = 60 * minutes + sec1 - sec0;
191 return seconds;
192}
193
194
195/* Return a time_t value corresponding to (YEAR-YDAY HOUR:MIN:SEC),
196 assuming that *T corresponds to *TP and that no clock adjustments
197 occurred between *TP and the desired time.
198 If TP is null, return a value not equal to *T; this avoids false matches.
199 If overflow occurs, yield the minimal or maximal value, except do not
200 yield a value equal to *T. */
201static time_t
202guess_time_tm (long int year, long int yday, int hour, int min, int sec,
203 const time_t *t, const struct tm *tp)
204{
205 if (tp)
206 {
207 time_t d = ydhms_diff (year, yday, hour, min, sec,
208 tp->tm_year, tp->tm_yday,
209 tp->tm_hour, tp->tm_min, tp->tm_sec);
210 time_t t1 = *t + d;
211 if ((t1 < *t) == (TYPE_SIGNED (time_t) ? d < 0 : TIME_T_MAX / 2 < d))
212 return t1;
213 }
214
215 /* Overflow occurred one way or another. Return the nearest result
216 that is actually in range, except don't report a zero difference
217 if the actual difference is nonzero, as that would cause a false
218 match; and don't oscillate between two values, as that would
219 confuse the spring-forward gap detector. */
220 return (*t < TIME_T_MIDPOINT
221 ? (*t <= TIME_T_MIN + 1 ? *t + 1 : TIME_T_MIN)
222 : (TIME_T_MAX - 1 <= *t ? *t - 1 : TIME_T_MAX));
223}
224
225/* Use CONVERT to convert *T to a broken down time in *TP.
226 If *T is out of range for conversion, adjust it so that
227 it is the nearest in-range value and then convert that. */
228static struct tm *
229ranged_convert (struct tm *(*convert) (const time_t *, struct tm *),
230 time_t *t, struct tm *tp)
231{
232 struct tm *r = convert (t, tp);
233
234 if (!r && *t)
235 {
236 time_t bad = *t;
237 time_t ok = 0;
238
239 /* BAD is a known unconvertible time_t, and OK is a known good one.
240 Use binary search to narrow the range between BAD and OK until
241 they differ by 1. */
242 while (bad != ok + (bad < 0 ? -1 : 1))
243 {
244 time_t mid = *t = (bad < 0
245 ? bad + ((ok - bad) >> 1)
246 : ok + ((bad - ok) >> 1));
247 r = convert (t, tp);
248 if (r)
249 ok = mid;
250 else
251 bad = mid;
252 }
253
254 if (!r && ok)
255 {
256 /* The last conversion attempt failed;
257 revert to the most recent successful attempt. */
258 *t = ok;
259 r = convert (t, tp);
260 }
261 }
262
263 return r;
264}
265
266
267/* Convert *TP to a time_t value, inverting
268 the monotonic and mostly-unit-linear conversion function CONVERT.
269 Use *OFFSET to keep track of a guess at the offset of the result,
270 compared to what the result would be for UTC without leap seconds.
271 If *OFFSET's guess is correct, only one CONVERT call is needed.
272 This function is external because it is used also by timegm.c. */
273time_t
274__mktime_internal (struct tm *tp,
275 struct tm *(*convert) (const time_t *, struct tm *),
276 time_t *offset)
277{
278 time_t t, gt, t0, t1, t2;
279 struct tm tm;
280
281 /* The maximum number of probes (calls to CONVERT) should be enough
282 to handle any combinations of time zone rule changes, solar time,
283 leap seconds, and oscillations around a spring-forward gap.
284 POSIX.1 prohibits leap seconds, but some hosts have them anyway. */
285 int remaining_probes = 6;
286
287 /* Time requested. Copy it in case CONVERT modifies *TP; this can
288 occur if TP is localtime's returned value and CONVERT is localtime. */
289 int sec = tp->tm_sec;
290 int min = tp->tm_min;
291 int hour = tp->tm_hour;
292 int mday = tp->tm_mday;
293 int mon = tp->tm_mon;
294 int year_requested = tp->tm_year;
295 int isdst = tp->tm_isdst;
296
297 /* 1 if the previous probe was DST. */
298 int dst2;
299
300 /* Ensure that mon is in range, and set year accordingly. */
301 int mon_remainder = mon % 12;
302 int negative_mon_remainder = mon_remainder < 0;
303 int mon_years = mon / 12 - negative_mon_remainder;
304 long int lyear_requested = year_requested;
305 long int year = lyear_requested + mon_years;
306
307 /* The other values need not be in range:
308 the remaining code handles minor overflows correctly,
309 assuming int and time_t arithmetic wraps around.
310 Major overflows are caught at the end. */
311
312 /* Calculate day of year from year, month, and day of month.
313 The result need not be in range. */
314 int mon_yday = ((__mon_yday[leapyear (year)]
315 [mon_remainder + 12 * negative_mon_remainder])
316 - 1);
317 long int lmday = mday;
318 long int yday = mon_yday + lmday;
319
320 time_t guessed_offset = *offset;
321
322 int sec_requested = sec;
323
324 if (LEAP_SECONDS_POSSIBLE)
325 {
326 /* Handle out-of-range seconds specially,
327 since ydhms_tm_diff assumes every minute has 60 seconds. */
328 if (sec < 0)
329 sec = 0;
330 if (59 < sec)
331 sec = 59;
332 }
333
334 /* Invert CONVERT by probing. First assume the same offset as last
335 time. */
336
337 t0 = ydhms_diff (year, yday, hour, min, sec,
338 EPOCH_YEAR - TM_YEAR_BASE, 0, 0, 0, - guessed_offset);
339
340 if (TIME_T_MAX / INT_MAX / 366 / 24 / 60 / 60 < 3)
341 {
342 /* time_t isn't large enough to rule out overflows, so check
343 for major overflows. A gross check suffices, since if t0
344 has overflowed, it is off by a multiple of TIME_T_MAX -
345 TIME_T_MIN + 1. So ignore any component of the difference
346 that is bounded by a small value. */
347
348 /* Approximate log base 2 of the number of time units per
349 biennium. A biennium is 2 years; use this unit instead of
350 years to avoid integer overflow. For example, 2 average
351 Gregorian years are 2 * 365.2425 * 24 * 60 * 60 seconds,
352 which is 63113904 seconds, and rint (log2 (63113904)) is
353 26. */
354 int ALOG2_SECONDS_PER_BIENNIUM = 26;
355 int ALOG2_MINUTES_PER_BIENNIUM = 20;
356 int ALOG2_HOURS_PER_BIENNIUM = 14;
357 int ALOG2_DAYS_PER_BIENNIUM = 10;
358 int LOG2_YEARS_PER_BIENNIUM = 1;
359
360 int approx_requested_biennia =
361 (SHR (year_requested, LOG2_YEARS_PER_BIENNIUM)
362 - SHR (EPOCH_YEAR - TM_YEAR_BASE, LOG2_YEARS_PER_BIENNIUM)
363 + SHR (mday, ALOG2_DAYS_PER_BIENNIUM)
364 + SHR (hour, ALOG2_HOURS_PER_BIENNIUM)
365 + SHR (min, ALOG2_MINUTES_PER_BIENNIUM)
366 + (LEAP_SECONDS_POSSIBLE
367 ? 0
368 : SHR (sec, ALOG2_SECONDS_PER_BIENNIUM)));
369
370 int approx_biennia = SHR (t0, ALOG2_SECONDS_PER_BIENNIUM);
371 int diff = approx_biennia - approx_requested_biennia;
372 int abs_diff = diff < 0 ? - diff : diff;
373
374 /* IRIX 4.0.5 cc miscaculates TIME_T_MIN / 3: it erroneously
375 gives a positive value of 715827882. Setting a variable
376 first then doing math on it seems to work.
377 (ghazi@caip.rutgers.edu) */
378 time_t time_t_max = TIME_T_MAX;
379 time_t time_t_min = TIME_T_MIN;
380 time_t overflow_threshold =
381 (time_t_max / 3 - time_t_min / 3) >> ALOG2_SECONDS_PER_BIENNIUM;
382
383 if (overflow_threshold < abs_diff)
384 {
385 /* Overflow occurred. Try repairing it; this might work if
386 the time zone offset is enough to undo the overflow. */
387 time_t repaired_t0 = -1 - t0;
388 approx_biennia = SHR (repaired_t0, ALOG2_SECONDS_PER_BIENNIUM);
389 diff = approx_biennia - approx_requested_biennia;
390 abs_diff = diff < 0 ? - diff : diff;
391 if (overflow_threshold < abs_diff)
392 return -1;
393 guessed_offset += repaired_t0 - t0;
394 t0 = repaired_t0;
395 }
396 }
397
398 /* Repeatedly use the error to improve the guess. */
399
400 for (t = t1 = t2 = t0, dst2 = 0;
401 (gt = guess_time_tm (year, yday, hour, min, sec, &t,
402 ranged_convert (convert, &t, &tm)),
403 t != gt);
404 t1 = t2, t2 = t, t = gt, dst2 = tm.tm_isdst != 0)
405 if (t == t1 && t != t2
406 && (tm.tm_isdst < 0
407 || (isdst < 0
408 ? dst2 <= (tm.tm_isdst != 0)
409 : (isdst != 0) != (tm.tm_isdst != 0))))
410 /* We can't possibly find a match, as we are oscillating
411 between two values. The requested time probably falls
412 within a spring-forward gap of size GT - T. Follow the common
413 practice in this case, which is to return a time that is GT - T
414 away from the requested time, preferring a time whose
415 tm_isdst differs from the requested value. (If no tm_isdst
416 was requested and only one of the two values has a nonzero
417 tm_isdst, prefer that value.) In practice, this is more
418 useful than returning -1. */
419 goto offset_found;
420 else if (--remaining_probes == 0)
421 return -1;
422
423 /* We have a match. Check whether tm.tm_isdst has the requested
424 value, if any. */
425 if (isdst != tm.tm_isdst && 0 <= isdst && 0 <= tm.tm_isdst)
426 {
427 /* tm.tm_isdst has the wrong value. Look for a neighboring
428 time with the right value, and use its UTC offset.
429
430 Heuristic: probe the adjacent timestamps in both directions,
431 looking for the desired isdst. This should work for all real
432 time zone histories in the tz database. */
433
434 /* Distance between probes when looking for a DST boundary. In
435 tzdata2003a, the shortest period of DST is 601200 seconds
436 (e.g., America/Recife starting 2000-10-08 01:00), and the
437 shortest period of non-DST surrounded by DST is 694800
438 seconds (Africa/Tunis starting 1943-04-17 01:00). Use the
439 minimum of these two values, so we don't miss these short
440 periods when probing. */
441 int stride = 601200;
442
443 /* The longest period of DST in tzdata2003a is 536454000 seconds
444 (e.g., America/Jujuy starting 1946-10-01 01:00). The longest
445 period of non-DST is much longer, but it makes no real sense
446 to search for more than a year of non-DST, so use the DST
447 max. */
448 int duration_max = 536454000;
449
450 /* Search in both directions, so the maximum distance is half
451 the duration; add the stride to avoid off-by-1 problems. */
452 int delta_bound = duration_max / 2 + stride;
453
454 int delta, direction;
455
456 for (delta = stride; delta < delta_bound; delta += stride)
457 for (direction = -1; direction <= 1; direction += 2)
458 {
459 time_t ot = t + delta * direction;
460 if ((ot < t) == (direction < 0))
461 {
462 struct tm otm;
463 ranged_convert (convert, &ot, &otm);
464 if (otm.tm_isdst == isdst)
465 {
466 /* We found the desired tm_isdst.
467 Extrapolate back to the desired time. */
468 t = guess_time_tm (year, yday, hour, min, sec, &ot, &otm);
469 ranged_convert (convert, &t, &tm);
470 goto offset_found;
471 }
472 }
473 }
474 }
475
476 offset_found:
477 *offset = guessed_offset + t - t0;
478
479 if (LEAP_SECONDS_POSSIBLE && sec_requested != tm.tm_sec)
480 {
481 /* Adjust time to reflect the tm_sec requested, not the normalized value.
482 Also, repair any damage from a false match due to a leap second. */
483 int sec_adjustment = (sec == 0 && tm.tm_sec == 60) - sec;
484 t1 = t + sec_requested;
485 t2 = t1 + sec_adjustment;
486 if (((t1 < t) != (sec_requested < 0))
487 | ((t2 < t1) != (sec_adjustment < 0))
488 | ! convert (&t2, &tm))
489 return -1;
490 t = t2;
491 }
492
493 *tp = tm;
494 return t;
495}
496
497
498/* FIXME: This should use a signed type wide enough to hold any UTC
499 offset in seconds. 'int' should be good enough for GNU code. We
500 can't fix this unilaterally though, as other modules invoke
501 __mktime_internal. */
502static time_t localtime_offset;
503
504/* Convert *TP to a time_t value. */
505time_t
506mktime (struct tm *tp)
507{
508#ifdef _LIBC
509 /* POSIX.1 8.1.1 requires that whenever mktime() is called, the
510 time zone names contained in the external variable `tzname' shall
511 be set as if the tzset() function had been called. */
512 __tzset ();
513#endif
514
515 return __mktime_internal (tp, __localtime_r, &localtime_offset);
516}
517
518#ifdef weak_alias
519weak_alias (mktime, timelocal)
520#endif
521
522#ifdef _LIBC
523libc_hidden_def (mktime)
524libc_hidden_weak (timelocal)
525#endif
526
527
528#if DEBUG
529
530static int
531not_equal_tm (const struct tm *a, const struct tm *b)
532{
533 return ((a->tm_sec ^ b->tm_sec)
534 | (a->tm_min ^ b->tm_min)
535 | (a->tm_hour ^ b->tm_hour)
536 | (a->tm_mday ^ b->tm_mday)
537 | (a->tm_mon ^ b->tm_mon)
538 | (a->tm_year ^ b->tm_year)
539 | (a->tm_yday ^ b->tm_yday)
540 | (a->tm_isdst ^ b->tm_isdst));
541}
542
543static void
544print_tm (const struct tm *tp)
545{
546 if (tp)
547 printf ("%04d-%02d-%02d %02d:%02d:%02d yday %03d wday %d isdst %d",
548 tp->tm_year + TM_YEAR_BASE, tp->tm_mon + 1, tp->tm_mday,
549 tp->tm_hour, tp->tm_min, tp->tm_sec,
550 tp->tm_yday, tp->tm_wday, tp->tm_isdst);
551 else
552 printf ("0");
553}
554
555static int
556check_result (time_t tk, struct tm tmk, time_t tl, const struct tm *lt)
557{
558 if (tk != tl || !lt || not_equal_tm (&tmk, lt))
559 {
560 printf ("mktime (");
561 print_tm (lt);
562 printf (")\nyields (");
563 print_tm (&tmk);
564 printf (") == %ld, should be %ld\n", (long int) tk, (long int) tl);
565 return 1;
566 }
567
568 return 0;
569}
570
571int
572main (int argc, char **argv)
573{
574 int status = 0;
575 struct tm tm, tmk, tml;
576 struct tm *lt;
577 time_t tk, tl, tl1;
578 char trailer;
579
580 if ((argc == 3 || argc == 4)
581 && (sscanf (argv[1], "%d-%d-%d%c",
582 &tm.tm_year, &tm.tm_mon, &tm.tm_mday, &trailer)
583 == 3)
584 && (sscanf (argv[2], "%d:%d:%d%c",
585 &tm.tm_hour, &tm.tm_min, &tm.tm_sec, &trailer)
586 == 3))
587 {
588 tm.tm_year -= TM_YEAR_BASE;
589 tm.tm_mon--;
590 tm.tm_isdst = argc == 3 ? -1 : atoi (argv[3]);
591 tmk = tm;
592 tl = mktime (&tmk);
593 lt = localtime (&tl);
594 if (lt)
595 {
596 tml = *lt;
597 lt = &tml;
598 }
599 printf ("mktime returns %ld == ", (long int) tl);
600 print_tm (&tmk);
601 printf ("\n");
602 status = check_result (tl, tmk, tl, lt);
603 }
604 else if (argc == 4 || (argc == 5 && strcmp (argv[4], "-") == 0))
605 {
606 time_t from = atol (argv[1]);
607 time_t by = atol (argv[2]);
608 time_t to = atol (argv[3]);
609
610 if (argc == 4)
611 for (tl = from; by < 0 ? to <= tl : tl <= to; tl = tl1)
612 {
613 lt = localtime (&tl);
614 if (lt)
615 {
616 tmk = tml = *lt;
617 tk = mktime (&tmk);
618 status |= check_result (tk, tmk, tl, &tml);
619 }
620 else
621 {
622 printf ("localtime (%ld) yields 0\n", (long int) tl);
623 status = 1;
624 }
625 tl1 = tl + by;
626 if ((tl1 < tl) != (by < 0))
627 break;
628 }
629 else
630 for (tl = from; by < 0 ? to <= tl : tl <= to; tl = tl1)
631 {
632 /* Null benchmark. */
633 lt = localtime (&tl);
634 if (lt)
635 {
636 tmk = tml = *lt;
637 tk = tl;
638 status |= check_result (tk, tmk, tl, &tml);
639 }
640 else
641 {
642 printf ("localtime (%ld) yields 0\n", (long int) tl);
643 status = 1;
644 }
645 tl1 = tl + by;
646 if ((tl1 < tl) != (by < 0))
647 break;
648 }
649 }
650 else
651 printf ("Usage:\
652\t%s YYYY-MM-DD HH:MM:SS [ISDST] # Test given time.\n\
653\t%s FROM BY TO # Test values FROM, FROM+BY, ..., TO.\n\
654\t%s FROM BY TO - # Do not test those values (for benchmark).\n",
655 argv[0], argv[0], argv[0]);
656
657 return status;
658}
659
660#endif /* DEBUG */
661
662
663/*
664Local Variables:
665compile-command: "gcc -DDEBUG -Wall -W -O -g mktime.c -o mktime"
666End:
667*/
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