1 /* -*- Mode: C++ -*- *****************************************************
2 * Written by various people (I"ll look up the exact credits later)
3 * Modified by Durk Talsma, July 1999 for use in FlightGear
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Library General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Library General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
19 **************************************************************************/
21 /********************************************************************
22 * This file redefines some low-level Unix-like time functions for *
23 * use with FlightGear. Most notably, localtime() is adapted to use *
24 * a custom timezone, in order to get the 'local' time for a given *
25 * aircraft's position, and not only for the current location of the*
26 * computer running the sim. *
28 * Software adapted from glibc functions, by Durk Talsma. Started *
30 ********************************************************************/
37 //#include <libc-lock.h>
44 #include <simgear/structure/exception.hxx>
46 #include "lowleveltime.h"
49 /* BIG FAT WARNING: NOTICE THAT I HARDCODED ENDIANNES. PLEASE CHANGE THIS */
51 #define BIG_ENDIAN 4321
55 #define LITTLE_ENDIAN 1234
59 #define BYTE_ORDER LITTLE_ENDIAN
67 /* END OF BIG FAT WARNING */
71 #define min(a, b) ((a) < (b) ? (a) : (b))
72 #define max(a, b) ((a) > (b) ? (a) : (b))
73 #define sign(x) ((x) < 0 ? -1 : 1)
77 time_t transition; /* Time the transition takes effect. */
78 long int change; /* Seconds of correction to apply. */
81 /* Header for a list of buffers containing time zone strings. */
84 struct tzstring_head *next;
85 /* The buffer itself immediately follows the header.
86 The buffer contains zero or more (possibly overlapping) strings.
87 The last string is followed by 2 '\0's instead of the usual 1. */
91 /* First in a list of buffers containing time zone strings.
92 All the buffers but the last are read-only. */
95 struct tzstring_head head;
99 /* Size of the last buffer in the list, not counting its header. */
100 static size_t tzstring_last_buffer_size = sizeof tzstring_list.data;
103 static char *old_fgtz = NULL;
104 static int use_fgtzfile = 1;
105 static int fgdaylight;
106 static char* fgtzname[2];
107 static long int fgtimezone;
110 static size_t num_transitions;
111 static time_t *transitions = NULL;
112 static unsigned char *type_idxs = NULL;
113 static size_t num_types;
114 static struct ttinfo *types = NULL;
115 static char *zone_names = NULL;
116 static size_t num_leaps;
117 static struct leap *leaps = NULL;
120 static void fgtzset_internal (int always, const char *tz);
121 static int fgtz_compute(time_t timer, const struct tm *tm);
122 static int fgcompute_change(fgtz_rule *rule, int year);
123 static struct ttinfo *fgfind_transition (time_t timer);
124 static void fgcompute_tzname_max (size_t chars);
125 static inline int decode (const void *ptr);
126 void fgtzfile_read (const char *file);
127 static void offtime (const time_t *t, long int offset, struct tm *tp);
128 static char *tzstring (const char* string);
130 /* tz_rules[0] is standard, tz_rules[1] is daylight. */
131 static fgtz_rule fgtz_rules[2];
133 int fgtzfile_compute (time_t timer, int use_localtime,
134 long int *leap_correct, int *leap_hit);
137 long int offset; /* Seconds east of GMT. */
138 unsigned char isdst; /* Used to set tm_isdst. */
139 unsigned char idx; /* Index into `zone_names'. */
140 unsigned char isstd; /* Transition times are in standard time. */
141 unsigned char isgmt; /* Transition times are in GMT. */
146 /* How many days come before each month (0-12). */
147 const unsigned short int mon_yday[2][13] =
150 { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 },
152 { 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 }
156 /* The C Standard says that localtime and gmtime return the same pointer. */
161 /* Nonzero if YEAR is a leap year (every 4 years,
162 except every 100th isn't, and every 400th is). */
163 # define isleap(year) \
164 ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))
170 /* Return the `struct tm' representation of *T in local time. */
171 struct tm * fgLocaltime (const time_t *t, const char *tzName)
173 return fgtz_convert (t, 1, &_fgtmbuf, tzName);
177 /* Return the `struct tm' representation of *TIMER in the local timezone.
178 Use local time if USE_LOCALTIME is nonzero, UTC otherwise. */
179 struct tm * fgtz_convert (const time_t *timer, int use_localtime, struct tm *tp, const char *tzName)
181 long int leap_correction;
182 long int offsetCorr; // ADDED TO RESOLVE NON-ANSI FIELDS IN struct tm
187 //set_errno (EINVAL);
191 //libc_lock_lock (tzset_lock);
193 /* Update internal database according to current TZ setting.
194 POSIX.1 8.3.7.2 says that localtime_r is not required to set tzname.
195 This is a good idea since this allows at least a bit more parallelism.
196 By analogy we apply the same rule to gmtime_r. */
197 fgtzset_internal (tp == &_fgtmbuf, tzName);
201 if (! fgtzfile_compute (*timer, use_localtime,
202 &leap_correction, &leap_extra_secs))
207 offtime (timer, 0, tp);
208 if (! fgtz_compute (*timer, tp))
210 leap_correction = 0L;
218 tp->tm_isdst = fgdaylight;
219 //tp->tm_zone = fgtzname[fgdaylight]; // NON_ANSI
220 //tp->tm_gmtoff = -fgtimezone; // NON_ANSI
221 offsetCorr = -fgtimezone;
226 //tp->tm_zone = "GMT"; // NON_ANSI
227 //tp->tm_gmtoff = 0L; // NON_ANSI
228 offsetCorr = -fgtimezone;
231 //offtime (timer, tp->tm_gmtoff - leap_correction, tp);
232 offtime (timer, offsetCorr - leap_correction, tp);
233 tp->tm_sec += leap_extra_secs;
236 //libc_lock_unlock (tzset_lock);
243 /* the following stuff is adapted from the tzCode package */
245 static size_t longest;
246 static char * abbr (struct tm * tmp);
248 void show(const char *zone, time_t t, int v)
252 (void) printf("%-*s ", (int) longest, zone);
254 (void) printf("%.24s UTC = ", asctime(gmtime(&t)));
255 tmp = fgLocaltime(&t, zone);
256 (void) printf("%.24s", asctime(tmp));
257 if (*abbr(tmp) != '\0')
258 (void) printf(" %s", abbr(tmp));
260 (void) printf(" isdst=%d", tmp->tm_isdst);
262 (void) printf(" gmtoff=%ld", tmp->TM_GMTOFF);
263 #endif /* defined TM_GMTOFF */
268 static char *abbr(struct tm *tmp)
270 register char * result;
273 if (tmp->tm_isdst != 0 && tmp->tm_isdst != 1)
275 result = fgtzname[tmp->tm_isdst];
276 return (result == NULL) ? &nada : result;
281 /***********************************************************************/
284 /* Interpret the TZ envariable. */
285 static void fgtzset_internal (int always, const char *tz)
289 static int is_initialized = 0;
290 //register const char *tz;
291 // register size_t l;
293 // unsigned short int hh, mm, ss;
294 // unsigned short int whichrule;
296 if (is_initialized && !always)
300 /* Examine the TZ environment variable. */
301 //tz = getenv ("TZ");
303 /* No user specification; use the site-wide default. */
305 else if (*tz == '\0')
306 /* User specified the empty string; use UTC explicitly. */
310 /* as you well know, mac paths contain leading colon, this code
311 messes things up.... */
313 /* A leading colon means "implementation defined syntax".
314 We ignore the colon and always use the same algorithm:
315 try a data file, and if none exists parse the 1003.1 syntax. */
316 if (tz && *tz == ':')
320 /* Check whether the value changes since the last run. */
321 if (old_fgtz != NULL && tz != NULL && strcmp (tz, old_fgtz) == 0)
322 /* No change, simply return. */
325 fgtz_rules[0].name = NULL;
326 fgtz_rules[1].name = NULL;
328 /* Save the value of `tz'. */
329 if (old_fgtz != NULL)
331 old_fgtz = tz ? strdup (tz) : NULL;
333 /* Try to read a data file. */
337 // The default behaviour of the original tzset_internal (int always, char* tz)
338 // function is to set up a default timezone, in any case file_read() fails
339 // Currently this leads to problems, because it modifies the system timezone
340 // and not the local aircraft timezone, contained in FlightGear. I could adapt
341 // this in future versions of this code, but doubt whether this is what we really
342 // want. So right now, throw an exception when timezone information reading failed.
343 // Guess I'll change that to something like 12 * (FG_LON / 180.0)
345 // For now, I'll leave it like this.
348 throw sg_exception("Timezone reading failed");
350 // this emacs "comment out" function is cool!
352 // // /* No data file found. Default to UTC if nothing specified. */
353 // // printf ("1. Current local time = %24s", asctime(localtime(&now)));
354 // if (tz == NULL || *tz == '\0')
356 // fgtz_rules[0].name = fgtz_rules[1].name = "UTC";
357 // fgtz_rules[0].type = fgtz_rules[1].type = fgtz_rule::J0;
358 // fgtz_rules[0].m = fgtz_rules[0].n = fgtz_rules[0].d = 0;
359 // fgtz_rules[1].m = fgtz_rules[1].n = fgtz_rules[1].d = 0;
360 // fgtz_rules[0].secs = fgtz_rules[1].secs = 0;
361 // fgtz_rules[0].offset = fgtz_rules[1].offset = 0L;
362 // fgtz_rules[0].change = fgtz_rules[1].change = (time_t) -1;
363 // fgtz_rules[0].computed_for = fgtz_rules[1].computed_for = 0;
367 // /* Clear out old state and reset to unnamed UTC. */
368 // //printf ("2. Current local time = %24s", asctime(localtime(&now)));
369 // memset (fgtz_rules, 0, sizeof fgtz_rules);
370 // fgtz_rules[0].name = fgtz_rules[1].name = "";
372 // /* Get the standard timezone name. */
373 // tzbuf = malloc (strlen (tz) + 1);
376 // /* Clear the old tz name so we will try again. */
381 // //printf ("3. Current local time = %24s", asctime(localtime(&now)));
382 // if (sscanf (tz, "%[^0-9,+-]", tzbuf) != 1 ||
383 // (l = strlen (tzbuf)) < 3)
389 // fgtz_rules[0].name = tzstring (tzbuf);
392 // //printf ("4. Current local time = %24s", asctime(localtime(&now)));
393 // /* Figure out the standard offset from UTC. */
394 // if (*tz == '\0' || (*tz != '+' && *tz != '-' && !isdigit (*tz)))
399 // //printf ("5. Current local time = %24s", asctime(localtime(&now)));
400 // if (*tz == '-' || *tz == '+')
401 // fgtz_rules[0].offset = *tz++ == '-' ? 1L : -1L;
403 // fgtz_rules[0].offset = -1L;
404 // switch (sscanf (tz, "%hu:%hu:%hu", &hh, &mm, &ss))
416 // //printf ("6. Current local time = %24s", asctime(localtime(&now)));
417 // fgtz_rules[0].offset *= (min (ss, 59) + (min (mm, 59) * 60) +
418 // (min (hh, 23) * 60 * 60));
420 // for (l = 0; l < 3; ++l)
422 // while (isdigit(*tz))
424 // if (l < 2 && *tz == ':')
427 // //printf ("7. Current local time = %24s", asctime(localtime(&now)));
428 // /* Get the DST timezone name (if any). */
431 // char *n = tzbuf + strlen (tzbuf) + 1;
432 // if (sscanf (tz, "%[^0-9,+-]", n) != 1 ||
433 // (l = strlen (n)) < 3)
434 // goto done_names; /* Punt on name, set up the offsets. */
435 // //printf ("7.1 Current local time = %24s", asctime(localtime(&now)));
436 // fgtz_rules[1].name = tzstring (n);
440 // /* Figure out the DST offset from GMT. */
441 // if (*tz == '-' || *tz == '+')
442 // fgtz_rules[1].offset = *tz++ == '-' ? 1L : -1L;
444 // fgtz_rules[1].offset = -1L;
445 // //printf ("7.2 Current local time = %24s", asctime(localtime(&now)));
446 // switch (sscanf (tz, "%hu:%hu:%hu", &hh, &mm, &ss))
449 // /* Default to one hour later than standard time. */
450 // fgtz_rules[1].offset = fgtz_rules[0].offset + (60 * 60);
458 // fgtz_rules[1].offset *= (min (ss, 59) + (min (mm, 59) * 60) +
459 // (min (hh, 23) * (60 * 60)));
462 // //printf ("7.3 Current local time = %24s", asctime(localtime(&now)));
463 // for (l = 0; l < 3; ++l)
465 // while (isdigit (*tz))
467 // if (l < 2 && *tz == ':')
470 // //printf ("7.4 Current local time = %24s", asctime(localtime(&now)));
471 // if (*tz == '\0' || (tz[0] == ',' && tz[1] == '\0'))
473 // /* There is no rule. See if there is a default rule file. */
474 // //printf ("7.4.1 Current local time = %24s", asctime(localtime(&now)));
475 // tzfile_default (fgtz_rules[0].name, fgtz_rules[1].name,
476 // fgtz_rules[0].offset, fgtz_rules[1].offset);
477 // //printf ("7.4.2 Current local time = %24s", asctime(localtime(&now)));
489 // /* There is no DST. */
490 // fgtz_rules[1].name = fgtz_rules[0].name;
494 // //printf ("7.5 Current local time = %24s", asctime(localtime(&now)));
496 // //printf ("8. Current local time = %24s", asctime(localtime(&now)));
499 // /* Figure out the standard <-> DST rules. */
500 // for (whichrule = 0; whichrule < 2; ++whichrule)
502 // register fgtz_rule *tzr = &fgtz_rules[whichrule];
504 // /* Ignore comma to support string following the incorrect
505 // specification in early POSIX.1 printings. */
508 // /* Get the date of the change. */
509 // if (*tz == 'J' || isdigit (*tz))
512 // tzr->type = *tz == 'J' ? fgtz_rule::J1 : fgtz_rule::J0;
513 // if (tzr->type == fgtz_rule::J1 && !isdigit (*++tz))
515 // tzr->d = (unsigned short int) strtoul (tz, &end, 10);
516 // if (end == tz || tzr->d > 365)
518 // else if (tzr->type == fgtz_rule::J1 && tzr->d == 0)
522 // else if (*tz == 'M')
525 // tzr->type = fgtz_rule::M;
526 // if (sscanf (tz, "M%hu.%hu.%hu%n",
527 // &tzr->m, &tzr->n, &tzr->d, &n) != 3 ||
528 // tzr->m < 1 || tzr->m > 12 ||
529 // tzr->n < 1 || tzr->n > 5 || tzr->d > 6)
533 // else if (*tz == '\0')
535 // /* United States Federal Law, the equivalent of "M4.1.0,M10.5.0". */
536 // tzr->type = fgtz_rule::M;
537 // if (tzr == &fgtz_rules[0])
552 // //printf ("9. Current local time = %24s", asctime(localtime(&now)));
553 // if (*tz != '\0' && *tz != '/' && *tz != ',')
555 // else if (*tz == '/')
557 // /* Get the time of day of the change. */
561 // switch (sscanf (tz, "%hu:%hu:%hu", &hh, &mm, &ss))
564 // hh = 2; /* Default to 2:00 AM. */
572 // for (l = 0; l < 3; ++l)
574 // while (isdigit (*tz))
576 // if (l < 2 && *tz == ':')
579 // tzr->secs = (hh * 60 * 60) + (mm * 60) + ss;
582 // /* Default to 2:00 AM. */
583 // tzr->secs = 2 * 60 * 60;
585 // tzr->computed_for = -1;
587 // // printf ("10. Current local time = %24s", asctime(localtime(&now)));
591 /************************************************************************/
594 /* Figure out the correct timezone for *TIMER and TM (which must be the same)
595 and set `tzname', `timezone', and `daylight' accordingly.
596 Return nonzero on success, zero on failure. */
597 size_t fgtzname_cur_max;
599 static int fgtz_compute (time_t timer, const struct tm* tm)
601 // const struct tm *tm;
603 if (! fgcompute_change (&fgtz_rules[0], 1900 + tm->tm_year) ||
604 ! fgcompute_change (&fgtz_rules[1], 1900 + tm->tm_year))
607 fgdaylight = timer >= fgtz_rules[0].change && timer < fgtz_rules[1].change;
608 fgtimezone = -fgtz_rules[fgdaylight].offset;
609 fgtzname[0] = (char *) fgtz_rules[0].name;
610 fgtzname[1] = (char *) fgtz_rules[1].name;
613 /* Keep tzname_cur_max up to date. */
614 size_t len0 = strlen (fgtzname[0]);
615 size_t len1 = strlen (fgtzname[1]);
616 if (len0 > fgtzname_cur_max)
617 fgtzname_cur_max = len0;
618 if (len1 > fgtzname_cur_max)
619 fgtzname_cur_max = len1;
625 /**********************************************************************/
627 /* Figure out the exact time (as a time_t) in YEAR
628 when the change described by RULE will occur and
629 put it in RULE->change, saving YEAR in RULE->computed_for.
630 Return nonzero if successful, zero on failure. */
631 static int fgcompute_change (fgtz_rule *rule, int year)
638 if (year != -1 && rule->computed_for == year)
639 /* Operations on times in 1969 will be slower. Oh well. */
642 /* First set T to January 1st, 0:00:00 GMT in YEAR. */
644 for (y = 1970; y < year; ++y)
645 t += SECSPERDAY * (isleap (y) ? 366 : 365);
650 /* Jn - Julian day, 1 == January 1, 60 == March 1 even in leap years.
651 In non-leap years, or if the day number is 59 or less, just
652 add SECSPERDAY times the day number-1 to the time of
653 January 1, midnight, to get the day. */
654 t += (rule->d - 1) * SECSPERDAY;
655 if (rule->d >= 60 && isleap (year))
661 Just add SECSPERDAY times the day number to the time of Jan 1st. */
662 t += rule->d * SECSPERDAY;
666 /* Mm.n.d - Nth "Dth day" of month M. */
668 register int i, d, m1, yy0, yy1, yy2, dow;
669 register const unsigned short int *myday =
670 &mon_yday[isleap (year)][rule->m];
672 /* First add SECSPERDAY for each day in months before M. */
673 t += myday[-1] * SECSPERDAY;
675 /* Use Zeller's Congruence to get day-of-week of first day of month. */
676 m1 = (rule->m + 9) % 12 + 1;
677 yy0 = (rule->m <= 2) ? (year - 1) : year;
680 dow = ((26 * m1 - 2) / 10 + 1 + yy2 + yy2 / 4 + yy1 / 4 - 2 * yy1) % 7;
684 /* DOW is the day-of-week of the first day of the month. Get the
685 day-of-month (zero-origin) of the first DOW day of the month. */
689 for (i = 1; i < rule->n; ++i)
691 if (d + 7 >= myday[0] - myday[-1])
696 /* D is the day-of-month (zero-origin) of the day we want. */
702 /* T is now the Epoch-relative time of 0:00:00 GMT on the day we want.
703 Just add the time of day and local offset from GMT, and we're done. */
705 rule->change = t - rule->offset + rule->secs;
706 rule->computed_for = year;
710 /*************************************************************************/
712 int fgtzfile_compute (time_t timer, int use_localtime,
713 long int *leap_correct, int *leap_hit)
719 struct ttinfo *info = fgfind_transition (timer);
720 fgdaylight = info->isdst;
721 fgtimezone = -info->offset;
723 i < num_types && i < sizeof (fgtzname) / sizeof (fgtzname[0]);
725 fgtzname[types[i].isdst] = &zone_names[types[i].idx];
726 if (info->isdst < sizeof (fgtzname) / sizeof (fgtzname[0]))
727 fgtzname[info->isdst] = &zone_names[info->idx];
733 /* Find the last leap second correction transition time before TIMER. */
738 while (timer < leaps[i].transition);
740 /* Apply its correction. */
741 *leap_correct = leaps[i].change;
743 if (timer == leaps[i].transition && /* Exactly at the transition time. */
744 ((i == 0 && leaps[i].change > 0) ||
745 leaps[i].change > leaps[i - 1].change))
749 leaps[i].transition == leaps[i - 1].transition + 1 &&
750 leaps[i].change == leaps[i - 1].change + 1)
760 /**************************************************************************/
762 static struct ttinfo * fgfind_transition (time_t timer)
766 if (num_transitions == 0 || timer < transitions[0])
768 /* TIMER is before any transition (or there are no transitions).
769 Choose the first non-DST type
770 (or the first if they're all DST types). */
772 while (i < num_types && types[i].isdst)
779 /* Find the first transition after TIMER, and
780 then pick the type of the transition before it. */
781 for (i = 1; i < num_transitions; ++i)
782 if (timer < transitions[i])
784 i = type_idxs[i - 1];
791 /**************************************************************************/
792 void fgtzfile_read (const char *file)
794 // static const char default_tzdir[] = TZDIR;
795 size_t num_isstd, num_isgmt;
797 struct tzhead tzhead;
804 if (transitions != NULL)
805 free ((void *) transitions);
807 if (type_idxs != NULL)
808 free ((void *) type_idxs);
811 free ((void *) types);
813 if (zone_names != NULL)
814 free ((void *) zone_names);
817 free ((void *) leaps);
821 /* No user specification; use the site-wide default. */
823 else if (*file == '\0')
824 /* User specified the empty string; use UTC with no leap seconds. */
828 /* We must not allow to read an arbitrary file in a setuid
829 program. So we fail for any file which is not in the
830 directory hierachy starting at TZDIR
831 and which is not the system wide default TZDEFAULT. */
832 //if (libc_enable_secure
834 // && memcmp (file, TZDEFAULT, sizeof TZDEFAULT)
835 // && memcmp (file, default_tzdir, sizeof (default_tzdir) - 1))
836 // || strstr (file, "../") != NULL))
837 /* This test is certainly a bit too restrictive but it should
838 catch all critical cases. */
842 // if (*file != '/') // if a relative path is used, append what file points to
843 // // to the path indicated by TZDIR.
845 // const char *tzdir;
846 // unsigned int len, tzdir_len;
849 // tzdir = getenv ("TZDIR");
850 // if (tzdir == NULL || *tzdir == '\0')
852 // tzdir = default_tzdir;
853 // tzdir_len = sizeof (default_tzdir) - 1;
856 // tzdir_len = strlen (tzdir);
857 // len = strlen (file) + 1;
858 // _new = (char *) alloca (tzdir_len + 1 + len);
859 // memcpy (_new, tzdir, tzdir_len);
860 // _new[tzdir_len] = '/';
861 // memcpy (&_new[tzdir_len + 1], file, len);
865 f = fopen (file, "rb");
868 perror( "fgtzfile_read(): " );
873 if (fread ((void *) &tzhead, sizeof (tzhead), 1, f) != 1)
876 num_transitions = (size_t) decode (tzhead.tzh_timecnt);
877 num_types = (size_t) decode (tzhead.tzh_typecnt);
878 chars = (size_t) decode (tzhead.tzh_charcnt);
879 num_leaps = (size_t) decode (tzhead.tzh_leapcnt);
880 num_isstd = (size_t) decode (tzhead.tzh_ttisstdcnt);
881 num_isgmt = (size_t) decode (tzhead.tzh_ttisgmtcnt);
883 if (num_transitions > 0)
885 transitions = (time_t *) malloc (num_transitions * sizeof(time_t));
886 if (transitions == NULL)
888 type_idxs = (unsigned char *) malloc (num_transitions);
889 if (type_idxs == NULL)
894 types = (struct ttinfo *) malloc (num_types * sizeof (struct ttinfo));
900 zone_names = (char *) malloc (chars);
901 if (zone_names == NULL)
906 leaps = (struct leap *) malloc (num_leaps * sizeof (struct leap));
911 if (sizeof (time_t) < 4)
914 if (fread(transitions, 4, num_transitions, f) != num_transitions ||
915 fread(type_idxs, 1, num_transitions, f) != num_transitions)
918 /* Check for bogus indices in the data file, so we can hereafter
919 safely use type_idxs[T] as indices into `types' and never crash. */
920 for (i = 0; i < num_transitions; ++i)
921 if (type_idxs[i] >= num_types)
924 if (BYTE_ORDER != BIG_ENDIAN || sizeof (time_t) != 4)
926 /* Decode the transition times, stored as 4-byte integers in
927 network (big-endian) byte order. We work from the end of
928 the array so as not to clobber the next element to be
929 processed when sizeof (time_t) > 4. */
932 transitions[i] = decode ((char *) transitions + i*4);
935 for (i = 0; i < num_types; ++i)
938 if (fread (x, 1, 4, f) != 4 ||
939 fread (&types[i].isdst, 1, 1, f) != 1 ||
940 fread (&types[i].idx, 1, 1, f) != 1)
942 if (types[i].idx >= chars) /* Bogus index in data file. */
944 types[i].offset = (long int) decode (x);
947 if (fread (zone_names, 1, chars, f) != chars)
950 for (i = 0; i < num_leaps; ++i)
953 if (fread (x, 1, sizeof (x), f) != sizeof (x))
955 leaps[i].transition = (time_t) decode (x);
956 if (fread (x, 1, sizeof (x), f) != sizeof (x))
958 leaps[i].change = (long int) decode (x);
961 for (i = 0; i < num_isstd; ++i)
966 types[i].isstd = c != 0;
968 while (i < num_types)
969 types[i++].isstd = 0;
971 for (i = 0; i < num_isgmt; ++i)
976 types[i].isgmt = c != 0;
978 while (i < num_types)
979 types[i++].isgmt = 0;
983 info = fgfind_transition (0);
984 for (i = 0; i < num_types && i < sizeof (fgtzname) / sizeof (fgtzname[0]);
986 fgtzname[types[i].isdst] = tzstring (&zone_names[types[i].idx]);
987 if (info->isdst < sizeof (fgtzname) / sizeof (fgtzname[0]))
988 fgtzname[info->isdst] = tzstring (&zone_names[info->idx]);
990 fgcompute_tzname_max (chars);
999 /****************************************************************************/
1000 static void fgcompute_tzname_max (size_t chars)
1002 // extern size_t tzname_cur_max; /* Defined in tzset.c. */
1009 const char *start = p;
1012 if ((size_t) (p - start) > fgtzname_cur_max)
1013 fgtzname_cur_max = p - start;
1014 } while (++p < &zone_names[chars]);
1017 /**************************************************************************/
1019 //#include <endian.h>
1021 /* Decode the four bytes at PTR as a signed integer in network byte order. */
1022 static inline int decode (const void *ptr)
1024 if ((BYTE_ORDER == BIG_ENDIAN) && sizeof (int) == 4)
1025 return *(const int *) ptr;
1028 const unsigned char *p = (unsigned char *)ptr;
1029 int result = *p & (1 << (CHAR_BIT - 1)) ? ~0 : 0;
1031 result = (result << 8) | *p++;
1032 result = (result << 8) | *p++;
1033 result = (result << 8) | *p++;
1034 result = (result << 8) | *p++;
1042 #define SECS_PER_HOUR (60 * 60)
1043 #define SECS_PER_DAY (SECS_PER_HOUR * 24)
1045 /* Compute the `struct tm' representation of *T,
1046 offset OFFSET seconds east of UTC,
1047 and store year, yday, mon, mday, wday, hour, min, sec into *TP. */
1049 void offtime (const time_t *t, long int offset, struct tm *tp)
1054 register long int days, rem, y;
1055 register const unsigned short int *ip;
1057 days = *t / SECS_PER_DAY;
1058 rem = *t % SECS_PER_DAY;
1062 rem += SECS_PER_DAY;
1065 while (rem >= SECS_PER_DAY)
1067 rem -= SECS_PER_DAY;
1070 tp->tm_hour = rem / SECS_PER_HOUR;
1071 rem %= SECS_PER_HOUR;
1072 tp->tm_min = rem / 60;
1073 tp->tm_sec = rem % 60;
1074 /* January 1, 1970 was a Thursday. */
1075 tp->tm_wday = (4 + days) % 7;
1076 if (tp->tm_wday < 0)
1080 #define LEAPS_THRU_END_OF(y) ((y) / 4 - (y) / 100 + (y) / 400)
1082 while (days < 0 || days >= (isleap (y) ? 366 : 365))
1084 /* Guess a corrected year, assuming 365 days per year. */
1085 long int yg = y + days / 365 - (days % 365 < 0);
1087 /* Adjust DAYS and Y to match the guessed year. */
1088 days -= ((yg - y) * 365
1089 + LEAPS_THRU_END_OF (yg - 1)
1090 - LEAPS_THRU_END_OF (y - 1));
1093 tp->tm_year = y - 1900;
1095 ip = mon_yday[isleap(y)];
1096 for (y = 11; days < ip[y]; --y)
1100 tp->tm_mday = days + 1;
1103 /* Allocate a time zone string with given contents.
1104 The string will never be moved or deallocated.
1105 However, its contents may be shared with other such strings. */
1106 char *tzstring (const char* string)
1107 //const char *string;
1109 struct tzstring_head *h = &tzstring_list.head;
1113 /* Look through time zone string list for a duplicate of this one. */
1114 for (h = &tzstring_list.head; ; h = h->next)
1116 for (p = (char *) (h + 1); p[0] | p[1]; ++p)
1117 if (strcmp (p, string) == 0)
1123 /* No duplicate was found. Copy to the end of this buffer if there's room;
1124 otherwise, append a large-enough new buffer to the list and use it. */
1126 needed = strlen (string) + 2; /* Need 2 trailing '\0's after last string. */
1128 if ((size_t) ((char *) (h + 1) + tzstring_last_buffer_size - p) < needed)
1130 size_t buffer_size = tzstring_last_buffer_size;
1131 while ((buffer_size *= 2) < needed)
1133 if (! (h = h->next = (struct tzstring_head *)malloc (sizeof *h + buffer_size)))
1136 tzstring_last_buffer_size = buffer_size;
1137 p = (char *) (h + 1);
1140 return strncpy (p, string, needed);