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 Library General Public
16 * License along with this library; if not, write to the
17 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 * Boston, MA 02111-1307, USA.
20 **************************************************************************/
22 /********************************************************************
23 * This file redefines some low-level Unix-like time functions for *
24 * use with FlightGear. Most notably, localtime() is adapted to use *
25 * a custom timezone, in order to get the 'local' time for a given *
26 * aircraft's position, and not only for the current location of the*
27 * computer running the sim. *
29 * Software adapted from glibc functions, by Durk Talsma. Started *
31 ********************************************************************/
38 //#include <libc-lock.h>
44 #include "lowleveltime.h"
47 /* BIG FAT WARNING: NOTICE THAT I HARDCODED ENDIANNES. PLEASE CHANGE THIS */
49 #define BIG_ENDIAN 4321
53 #define LITTLE_ENDIAN 1234
57 #define BYTE_ORDER LITTLE_ENDIAN
65 /* END OF BIG FAT WARNING */
69 #define min(a, b) ((a) < (b) ? (a) : (b))
70 #define max(a, b) ((a) > (b) ? (a) : (b))
71 #define sign(x) ((x) < 0 ? -1 : 1)
75 time_t transition; /* Time the transition takes effect. */
76 long int change; /* Seconds of correction to apply. */
79 /* Header for a list of buffers containing time zone strings. */
82 struct tzstring_head *next;
83 /* The buffer itself immediately follows the header.
84 The buffer contains zero or more (possibly overlapping) strings.
85 The last string is followed by 2 '\0's instead of the usual 1. */
89 /* First in a list of buffers containing time zone strings.
90 All the buffers but the last are read-only. */
93 struct tzstring_head head;
97 /* Size of the last buffer in the list, not counting its header. */
98 static size_t tzstring_last_buffer_size = sizeof tzstring_list.data;
101 static char *old_fgtz = NULL;
102 static int use_fgtzfile = 1;
103 static int fgdaylight;
104 static char* fgtzname[2];
105 static long int fgtimezone;
108 static size_t num_transitions;
109 static time_t *transitions = NULL;
110 static unsigned char *type_idxs = NULL;
111 static size_t num_types;
112 static struct ttinfo *types = NULL;
113 static char *zone_names = NULL;
114 static size_t num_leaps;
115 static struct leap *leaps = NULL;
118 static void fgtzset_internal (int always, const char *tz);
119 static int fgtz_compute(time_t timer, const struct tm *tm);
120 static int fgcompute_change(fgtz_rule *rule, int year);
121 static struct ttinfo *fgfind_transition (time_t timer);
122 static void fgcompute_tzname_max (size_t chars);
123 static inline int decode (const void *ptr);
124 void fgtzfile_read (const char *file);
125 static void offtime (const time_t *t, long int offset, struct tm *tp);
126 static char *tzstring (const char* string);
128 /* tz_rules[0] is standard, tz_rules[1] is daylight. */
129 static fgtz_rule fgtz_rules[2];
131 int fgtzfile_compute (time_t timer, int use_localtime,
132 long int *leap_correct, int *leap_hit);
135 long int offset; /* Seconds east of GMT. */
136 unsigned char isdst; /* Used to set tm_isdst. */
137 unsigned char idx; /* Index into `zone_names'. */
138 unsigned char isstd; /* Transition times are in standard time. */
139 unsigned char isgmt; /* Transition times are in GMT. */
144 /* How many days come before each month (0-12). */
145 const unsigned short int mon_yday[2][13] =
148 { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 },
150 { 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 }
154 /* The C Standard says that localtime and gmtime return the same pointer. */
159 /* Nonzero if YEAR is a leap year (every 4 years,
160 except every 100th isn't, and every 400th is). */
161 # define isleap(year) \
162 ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))
168 /* Return the `struct tm' representation of *T in local time. */
169 struct tm * fgLocaltime (const time_t *t, const char *tzName)
171 return fgtz_convert (t, 1, &_fgtmbuf, tzName);
175 /* Return the `struct tm' representation of *TIMER in the local timezone.
176 Use local time if USE_LOCALTIME is nonzero, UTC otherwise. */
177 struct tm * fgtz_convert (const time_t *timer, int use_localtime, struct tm *tp, const char *tzName)
179 long int leap_correction;
180 long int offsetCorr; // ADDED TO RESOLVE NON-ANSI FIELDS IN struct tm
185 //set_errno (EINVAL);
189 //libc_lock_lock (tzset_lock);
191 /* Update internal database according to current TZ setting.
192 POSIX.1 8.3.7.2 says that localtime_r is not required to set tzname.
193 This is a good idea since this allows at least a bit more parallelism.
194 By analogy we apply the same rule to gmtime_r. */
195 fgtzset_internal (tp == &_fgtmbuf, tzName);
199 if (! fgtzfile_compute (*timer, use_localtime,
200 &leap_correction, &leap_extra_secs))
205 offtime (timer, 0, tp);
206 if (! fgtz_compute (*timer, tp))
208 leap_correction = 0L;
216 tp->tm_isdst = fgdaylight;
217 //tp->tm_zone = fgtzname[fgdaylight]; // NON_ANSI
218 //tp->tm_gmtoff = -fgtimezone; // NON_ANSI
219 offsetCorr = -fgtimezone;
224 //tp->tm_zone = "GMT"; // NON_ANSI
225 //tp->tm_gmtoff = 0L; // NON_ANSI
226 offsetCorr = -fgtimezone;
229 //offtime (timer, tp->tm_gmtoff - leap_correction, tp);
230 offtime (timer, offsetCorr - leap_correction, tp);
231 tp->tm_sec += leap_extra_secs;
234 //libc_lock_unlock (tzset_lock);
241 /* the following stuff is adapted from the tzCode package */
243 static size_t longest;
244 static char * abbr (struct tm * tmp);
246 void show(const char *zone, time_t t, int v)
250 (void) printf("%-*s ", (int) longest, zone);
252 (void) printf("%.24s UTC = ", asctime(gmtime(&t)));
253 tmp = fgLocaltime(&t, zone);
254 (void) printf("%.24s", asctime(tmp));
255 if (*abbr(tmp) != '\0')
256 (void) printf(" %s", abbr(tmp));
258 (void) printf(" isdst=%d", tmp->tm_isdst);
260 (void) printf(" gmtoff=%ld", tmp->TM_GMTOFF);
261 #endif /* defined TM_GMTOFF */
266 static char *abbr(struct tm *tmp)
268 register char * result;
271 if (tmp->tm_isdst != 0 && tmp->tm_isdst != 1)
273 result = fgtzname[tmp->tm_isdst];
274 return (result == NULL) ? &nada : result;
279 /***********************************************************************/
282 /* Interpret the TZ envariable. */
283 static void fgtzset_internal (int always, const char *tz)
287 static int is_initialized = 0;
288 //register const char *tz;
289 // register size_t l;
291 // unsigned short int hh, mm, ss;
292 // unsigned short int whichrule;
294 if (is_initialized && !always)
298 /* Examine the TZ environment variable. */
299 //tz = getenv ("TZ");
301 /* No user specification; use the site-wide default. */
303 else if (*tz == '\0')
304 /* User specified the empty string; use UTC explicitly. */
308 /* as you well know, mac paths contain leading colon, this code
309 messes things up.... */
311 /* A leading colon means "implementation defined syntax".
312 We ignore the colon and always use the same algorithm:
313 try a data file, and if none exists parse the 1003.1 syntax. */
314 if (tz && *tz == ':')
318 /* Check whether the value changes since the last run. */
319 if (old_fgtz != NULL && tz != NULL && strcmp (tz, old_fgtz) == 0)
320 /* No change, simply return. */
323 fgtz_rules[0].name = NULL;
324 fgtz_rules[1].name = NULL;
326 /* Save the value of `tz'. */
327 if (old_fgtz != NULL)
329 old_fgtz = tz ? strdup (tz) : NULL;
331 /* Try to read a data file. */
335 // The default behaviour of the originale tzset_internal (int always, char* tz)
336 // function is to set up a default timezone, in any casetz file_read() fails
337 // Currently this leads to problems, because it modidifies the system timezone
338 // and not the local aircraft timezone, contained in FlightGear. I could adapt
339 // this in future versions of this code, but doubt whether this is what we really
340 // want. So right now, exit when timezone information reading failed.
341 // Guess I'll change that to something like 12 * (FG_LON / 180.0)
343 // For now, I'll leave it like this.
346 printf ("Timezone reading failed\n");
349 // this emacs "comment out" function is cool!
351 // // /* No data file found. Default to UTC if nothing specified. */
352 // // printf ("1. Current local time = %24s", asctime(localtime(&now)));
353 // if (tz == NULL || *tz == '\0')
355 // fgtz_rules[0].name = fgtz_rules[1].name = "UTC";
356 // fgtz_rules[0].type = fgtz_rules[1].type = fgtz_rule::J0;
357 // fgtz_rules[0].m = fgtz_rules[0].n = fgtz_rules[0].d = 0;
358 // fgtz_rules[1].m = fgtz_rules[1].n = fgtz_rules[1].d = 0;
359 // fgtz_rules[0].secs = fgtz_rules[1].secs = 0;
360 // fgtz_rules[0].offset = fgtz_rules[1].offset = 0L;
361 // fgtz_rules[0].change = fgtz_rules[1].change = (time_t) -1;
362 // fgtz_rules[0].computed_for = fgtz_rules[1].computed_for = 0;
366 // /* Clear out old state and reset to unnamed UTC. */
367 // //printf ("2. Current local time = %24s", asctime(localtime(&now)));
368 // memset (fgtz_rules, 0, sizeof fgtz_rules);
369 // fgtz_rules[0].name = fgtz_rules[1].name = "";
371 // /* Get the standard timezone name. */
372 // tzbuf = malloc (strlen (tz) + 1);
375 // /* Clear the old tz name so we will try again. */
380 // //printf ("3. Current local time = %24s", asctime(localtime(&now)));
381 // if (sscanf (tz, "%[^0-9,+-]", tzbuf) != 1 ||
382 // (l = strlen (tzbuf)) < 3)
388 // fgtz_rules[0].name = tzstring (tzbuf);
391 // //printf ("4. Current local time = %24s", asctime(localtime(&now)));
392 // /* Figure out the standard offset from UTC. */
393 // if (*tz == '\0' || (*tz != '+' && *tz != '-' && !isdigit (*tz)))
398 // //printf ("5. Current local time = %24s", asctime(localtime(&now)));
399 // if (*tz == '-' || *tz == '+')
400 // fgtz_rules[0].offset = *tz++ == '-' ? 1L : -1L;
402 // fgtz_rules[0].offset = -1L;
403 // switch (sscanf (tz, "%hu:%hu:%hu", &hh, &mm, &ss))
415 // //printf ("6. Current local time = %24s", asctime(localtime(&now)));
416 // fgtz_rules[0].offset *= (min (ss, 59) + (min (mm, 59) * 60) +
417 // (min (hh, 23) * 60 * 60));
419 // for (l = 0; l < 3; ++l)
421 // while (isdigit(*tz))
423 // if (l < 2 && *tz == ':')
426 // //printf ("7. Current local time = %24s", asctime(localtime(&now)));
427 // /* Get the DST timezone name (if any). */
430 // char *n = tzbuf + strlen (tzbuf) + 1;
431 // if (sscanf (tz, "%[^0-9,+-]", n) != 1 ||
432 // (l = strlen (n)) < 3)
433 // goto done_names; /* Punt on name, set up the offsets. */
434 // //printf ("7.1 Current local time = %24s", asctime(localtime(&now)));
435 // fgtz_rules[1].name = tzstring (n);
439 // /* Figure out the DST offset from GMT. */
440 // if (*tz == '-' || *tz == '+')
441 // fgtz_rules[1].offset = *tz++ == '-' ? 1L : -1L;
443 // fgtz_rules[1].offset = -1L;
444 // //printf ("7.2 Current local time = %24s", asctime(localtime(&now)));
445 // switch (sscanf (tz, "%hu:%hu:%hu", &hh, &mm, &ss))
448 // /* Default to one hour later than standard time. */
449 // fgtz_rules[1].offset = fgtz_rules[0].offset + (60 * 60);
457 // fgtz_rules[1].offset *= (min (ss, 59) + (min (mm, 59) * 60) +
458 // (min (hh, 23) * (60 * 60)));
461 // //printf ("7.3 Current local time = %24s", asctime(localtime(&now)));
462 // for (l = 0; l < 3; ++l)
464 // while (isdigit (*tz))
466 // if (l < 2 && *tz == ':')
469 // //printf ("7.4 Current local time = %24s", asctime(localtime(&now)));
470 // if (*tz == '\0' || (tz[0] == ',' && tz[1] == '\0'))
472 // /* There is no rule. See if there is a default rule file. */
473 // //printf ("7.4.1 Current local time = %24s", asctime(localtime(&now)));
474 // tzfile_default (fgtz_rules[0].name, fgtz_rules[1].name,
475 // fgtz_rules[0].offset, fgtz_rules[1].offset);
476 // //printf ("7.4.2 Current local time = %24s", asctime(localtime(&now)));
488 // /* There is no DST. */
489 // fgtz_rules[1].name = fgtz_rules[0].name;
493 // //printf ("7.5 Current local time = %24s", asctime(localtime(&now)));
495 // //printf ("8. Current local time = %24s", asctime(localtime(&now)));
498 // /* Figure out the standard <-> DST rules. */
499 // for (whichrule = 0; whichrule < 2; ++whichrule)
501 // register fgtz_rule *tzr = &fgtz_rules[whichrule];
503 // /* Ignore comma to support string following the incorrect
504 // specification in early POSIX.1 printings. */
507 // /* Get the date of the change. */
508 // if (*tz == 'J' || isdigit (*tz))
511 // tzr->type = *tz == 'J' ? fgtz_rule::J1 : fgtz_rule::J0;
512 // if (tzr->type == fgtz_rule::J1 && !isdigit (*++tz))
514 // tzr->d = (unsigned short int) strtoul (tz, &end, 10);
515 // if (end == tz || tzr->d > 365)
517 // else if (tzr->type == fgtz_rule::J1 && tzr->d == 0)
521 // else if (*tz == 'M')
524 // tzr->type = fgtz_rule::M;
525 // if (sscanf (tz, "M%hu.%hu.%hu%n",
526 // &tzr->m, &tzr->n, &tzr->d, &n) != 3 ||
527 // tzr->m < 1 || tzr->m > 12 ||
528 // tzr->n < 1 || tzr->n > 5 || tzr->d > 6)
532 // else if (*tz == '\0')
534 // /* United States Federal Law, the equivalent of "M4.1.0,M10.5.0". */
535 // tzr->type = fgtz_rule::M;
536 // if (tzr == &fgtz_rules[0])
551 // //printf ("9. Current local time = %24s", asctime(localtime(&now)));
552 // if (*tz != '\0' && *tz != '/' && *tz != ',')
554 // else if (*tz == '/')
556 // /* Get the time of day of the change. */
560 // switch (sscanf (tz, "%hu:%hu:%hu", &hh, &mm, &ss))
563 // hh = 2; /* Default to 2:00 AM. */
571 // for (l = 0; l < 3; ++l)
573 // while (isdigit (*tz))
575 // if (l < 2 && *tz == ':')
578 // tzr->secs = (hh * 60 * 60) + (mm * 60) + ss;
581 // /* Default to 2:00 AM. */
582 // tzr->secs = 2 * 60 * 60;
584 // tzr->computed_for = -1;
586 // // printf ("10. Current local time = %24s", asctime(localtime(&now)));
590 /************************************************************************/
593 /* Figure out the correct timezone for *TIMER and TM (which must be the same)
594 and set `tzname', `timezone', and `daylight' accordingly.
595 Return nonzero on success, zero on failure. */
596 size_t fgtzname_cur_max;
598 static int fgtz_compute (time_t timer, const struct tm* tm)
600 // const struct tm *tm;
602 if (! fgcompute_change (&fgtz_rules[0], 1900 + tm->tm_year) ||
603 ! fgcompute_change (&fgtz_rules[1], 1900 + tm->tm_year))
606 fgdaylight = timer >= fgtz_rules[0].change && timer < fgtz_rules[1].change;
607 fgtimezone = -fgtz_rules[fgdaylight].offset;
608 fgtzname[0] = (char *) fgtz_rules[0].name;
609 fgtzname[1] = (char *) fgtz_rules[1].name;
612 /* Keep tzname_cur_max up to date. */
613 size_t len0 = strlen (fgtzname[0]);
614 size_t len1 = strlen (fgtzname[1]);
615 if (len0 > fgtzname_cur_max)
616 fgtzname_cur_max = len0;
617 if (len1 > fgtzname_cur_max)
618 fgtzname_cur_max = len1;
624 /**********************************************************************/
626 /* Figure out the exact time (as a time_t) in YEAR
627 when the change described by RULE will occur and
628 put it in RULE->change, saving YEAR in RULE->computed_for.
629 Return nonzero if successful, zero on failure. */
630 static int fgcompute_change (fgtz_rule *rule, int year)
637 if (year != -1 && rule->computed_for == year)
638 /* Operations on times in 1969 will be slower. Oh well. */
641 /* First set T to January 1st, 0:00:00 GMT in YEAR. */
643 for (y = 1970; y < year; ++y)
644 t += SECSPERDAY * (isleap (y) ? 366 : 365);
649 /* Jn - Julian day, 1 == January 1, 60 == March 1 even in leap years.
650 In non-leap years, or if the day number is 59 or less, just
651 add SECSPERDAY times the day number-1 to the time of
652 January 1, midnight, to get the day. */
653 t += (rule->d - 1) * SECSPERDAY;
654 if (rule->d >= 60 && isleap (year))
660 Just add SECSPERDAY times the day number to the time of Jan 1st. */
661 t += rule->d * SECSPERDAY;
665 /* Mm.n.d - Nth "Dth day" of month M. */
667 register int i, d, m1, yy0, yy1, yy2, dow;
668 register const unsigned short int *myday =
669 &mon_yday[isleap (year)][rule->m];
671 /* First add SECSPERDAY for each day in months before M. */
672 t += myday[-1] * SECSPERDAY;
674 /* Use Zeller's Congruence to get day-of-week of first day of month. */
675 m1 = (rule->m + 9) % 12 + 1;
676 yy0 = (rule->m <= 2) ? (year - 1) : year;
679 dow = ((26 * m1 - 2) / 10 + 1 + yy2 + yy2 / 4 + yy1 / 4 - 2 * yy1) % 7;
683 /* DOW is the day-of-week of the first day of the month. Get the
684 day-of-month (zero-origin) of the first DOW day of the month. */
688 for (i = 1; i < rule->n; ++i)
690 if (d + 7 >= myday[0] - myday[-1])
695 /* D is the day-of-month (zero-origin) of the day we want. */
701 /* T is now the Epoch-relative time of 0:00:00 GMT on the day we want.
702 Just add the time of day and local offset from GMT, and we're done. */
704 rule->change = t - rule->offset + rule->secs;
705 rule->computed_for = year;
709 /*************************************************************************/
711 int fgtzfile_compute (time_t timer, int use_localtime,
712 long int *leap_correct, int *leap_hit)
718 struct ttinfo *info = fgfind_transition (timer);
719 fgdaylight = info->isdst;
720 fgtimezone = -info->offset;
722 i < num_types && i < sizeof (fgtzname) / sizeof (fgtzname[0]);
724 fgtzname[types[i].isdst] = &zone_names[types[i].idx];
725 if (info->isdst < sizeof (fgtzname) / sizeof (fgtzname[0]))
726 fgtzname[info->isdst] = &zone_names[info->idx];
732 /* Find the last leap second correction transition time before TIMER. */
737 while (timer < leaps[i].transition);
739 /* Apply its correction. */
740 *leap_correct = leaps[i].change;
742 if (timer == leaps[i].transition && /* Exactly at the transition time. */
743 ((i == 0 && leaps[i].change > 0) ||
744 leaps[i].change > leaps[i - 1].change))
748 leaps[i].transition == leaps[i - 1].transition + 1 &&
749 leaps[i].change == leaps[i - 1].change + 1)
759 /**************************************************************************/
761 static struct ttinfo * fgfind_transition (time_t timer)
765 if (num_transitions == 0 || timer < transitions[0])
767 /* TIMER is before any transition (or there are no transitions).
768 Choose the first non-DST type
769 (or the first if they're all DST types). */
771 while (i < num_types && types[i].isdst)
778 /* Find the first transition after TIMER, and
779 then pick the type of the transition before it. */
780 for (i = 1; i < num_transitions; ++i)
781 if (timer < transitions[i])
783 i = type_idxs[i - 1];
790 /**************************************************************************/
791 void fgtzfile_read (const char *file)
793 // static const char default_tzdir[] = TZDIR;
794 size_t num_isstd, num_isgmt;
796 struct tzhead tzhead;
803 if (transitions != NULL)
804 free ((void *) transitions);
806 if (type_idxs != NULL)
807 free ((void *) type_idxs);
810 free ((void *) types);
812 if (zone_names != NULL)
813 free ((void *) zone_names);
816 free ((void *) leaps);
820 /* No user specification; use the site-wide default. */
822 else if (*file == '\0')
823 /* User specified the empty string; use UTC with no leap seconds. */
827 /* We must not allow to read an arbitrary file in a setuid
828 program. So we fail for any file which is not in the
829 directory hierachy starting at TZDIR
830 and which is not the system wide default TZDEFAULT. */
831 //if (libc_enable_secure
833 // && memcmp (file, TZDEFAULT, sizeof TZDEFAULT)
834 // && memcmp (file, default_tzdir, sizeof (default_tzdir) - 1))
835 // || strstr (file, "../") != NULL))
836 /* This test is certainly a bit too restrictive but it should
837 catch all critical cases. */
841 // if (*file != '/') // if a relative path is used, append what file points to
842 // // to the path indicated by TZDIR.
844 // const char *tzdir;
845 // unsigned int len, tzdir_len;
848 // tzdir = getenv ("TZDIR");
849 // if (tzdir == NULL || *tzdir == '\0')
851 // tzdir = default_tzdir;
852 // tzdir_len = sizeof (default_tzdir) - 1;
855 // tzdir_len = strlen (tzdir);
856 // len = strlen (file) + 1;
857 // _new = (char *) alloca (tzdir_len + 1 + len);
858 // memcpy (_new, tzdir, tzdir_len);
859 // _new[tzdir_len] = '/';
860 // memcpy (&_new[tzdir_len + 1], file, len);
864 f = fopen (file, "rb");
867 perror( "fgtzfile_read(): " );
872 if (fread ((void *) &tzhead, sizeof (tzhead), 1, f) != 1)
875 num_transitions = (size_t) decode (tzhead.tzh_timecnt);
876 num_types = (size_t) decode (tzhead.tzh_typecnt);
877 chars = (size_t) decode (tzhead.tzh_charcnt);
878 num_leaps = (size_t) decode (tzhead.tzh_leapcnt);
879 num_isstd = (size_t) decode (tzhead.tzh_ttisstdcnt);
880 num_isgmt = (size_t) decode (tzhead.tzh_ttisgmtcnt);
882 if (num_transitions > 0)
884 transitions = (time_t *) malloc (num_transitions * sizeof(time_t));
885 if (transitions == NULL)
887 type_idxs = (unsigned char *) malloc (num_transitions);
888 if (type_idxs == NULL)
893 types = (struct ttinfo *) malloc (num_types * sizeof (struct ttinfo));
899 zone_names = (char *) malloc (chars);
900 if (zone_names == NULL)
905 leaps = (struct leap *) malloc (num_leaps * sizeof (struct leap));
910 if (sizeof (time_t) < 4)
913 if (fread(transitions, 4, num_transitions, f) != num_transitions ||
914 fread(type_idxs, 1, num_transitions, f) != num_transitions)
917 /* Check for bogus indices in the data file, so we can hereafter
918 safely use type_idxs[T] as indices into `types' and never crash. */
919 for (i = 0; i < num_transitions; ++i)
920 if (type_idxs[i] >= num_types)
923 if (BYTE_ORDER != BIG_ENDIAN || sizeof (time_t) != 4)
925 /* Decode the transition times, stored as 4-byte integers in
926 network (big-endian) byte order. We work from the end of
927 the array so as not to clobber the next element to be
928 processed when sizeof (time_t) > 4. */
931 transitions[i] = decode ((char *) transitions + i*4);
934 for (i = 0; i < num_types; ++i)
937 if (fread (x, 1, 4, f) != 4 ||
938 fread (&types[i].isdst, 1, 1, f) != 1 ||
939 fread (&types[i].idx, 1, 1, f) != 1)
941 if (types[i].idx >= chars) /* Bogus index in data file. */
943 types[i].offset = (long int) decode (x);
946 if (fread (zone_names, 1, chars, f) != chars)
949 for (i = 0; i < num_leaps; ++i)
952 if (fread (x, 1, sizeof (x), f) != sizeof (x))
954 leaps[i].transition = (time_t) decode (x);
955 if (fread (x, 1, sizeof (x), f) != sizeof (x))
957 leaps[i].change = (long int) decode (x);
960 for (i = 0; i < num_isstd; ++i)
965 types[i].isstd = c != 0;
967 while (i < num_types)
968 types[i++].isstd = 0;
970 for (i = 0; i < num_isgmt; ++i)
975 types[i].isgmt = c != 0;
977 while (i < num_types)
978 types[i++].isgmt = 0;
982 info = fgfind_transition (0);
983 for (i = 0; i < num_types && i < sizeof (fgtzname) / sizeof (fgtzname[0]);
985 fgtzname[types[i].isdst] = tzstring (&zone_names[types[i].idx]);
986 if (info->isdst < sizeof (fgtzname) / sizeof (fgtzname[0]))
987 fgtzname[info->isdst] = tzstring (&zone_names[info->idx]);
989 fgcompute_tzname_max (chars);
998 /****************************************************************************/
999 static void fgcompute_tzname_max (size_t chars)
1001 // extern size_t tzname_cur_max; /* Defined in tzset.c. */
1008 const char *start = p;
1011 if ((size_t) (p - start) > fgtzname_cur_max)
1012 fgtzname_cur_max = p - start;
1013 } while (++p < &zone_names[chars]);
1016 /**************************************************************************/
1018 //#include <endian.h>
1020 /* Decode the four bytes at PTR as a signed integer in network byte order. */
1021 static inline int decode (const void *ptr)
1023 if ((BYTE_ORDER == BIG_ENDIAN) && sizeof (int) == 4)
1024 return *(const int *) ptr;
1027 const unsigned char *p = (unsigned char *)ptr;
1028 int result = *p & (1 << (CHAR_BIT - 1)) ? ~0 : 0;
1030 result = (result << 8) | *p++;
1031 result = (result << 8) | *p++;
1032 result = (result << 8) | *p++;
1033 result = (result << 8) | *p++;
1041 #define SECS_PER_HOUR (60 * 60)
1042 #define SECS_PER_DAY (SECS_PER_HOUR * 24)
1044 /* Compute the `struct tm' representation of *T,
1045 offset OFFSET seconds east of UTC,
1046 and store year, yday, mon, mday, wday, hour, min, sec into *TP. */
1048 void offtime (const time_t *t, long int offset, struct tm *tp)
1053 register long int days, rem, y;
1054 register const unsigned short int *ip;
1056 days = *t / SECS_PER_DAY;
1057 rem = *t % SECS_PER_DAY;
1061 rem += SECS_PER_DAY;
1064 while (rem >= SECS_PER_DAY)
1066 rem -= SECS_PER_DAY;
1069 tp->tm_hour = rem / SECS_PER_HOUR;
1070 rem %= SECS_PER_HOUR;
1071 tp->tm_min = rem / 60;
1072 tp->tm_sec = rem % 60;
1073 /* January 1, 1970 was a Thursday. */
1074 tp->tm_wday = (4 + days) % 7;
1075 if (tp->tm_wday < 0)
1079 #define LEAPS_THRU_END_OF(y) ((y) / 4 - (y) / 100 + (y) / 400)
1081 while (days < 0 || days >= (isleap (y) ? 366 : 365))
1083 /* Guess a corrected year, assuming 365 days per year. */
1084 long int yg = y + days / 365 - (days % 365 < 0);
1086 /* Adjust DAYS and Y to match the guessed year. */
1087 days -= ((yg - y) * 365
1088 + LEAPS_THRU_END_OF (yg - 1)
1089 - LEAPS_THRU_END_OF (y - 1));
1092 tp->tm_year = y - 1900;
1094 ip = mon_yday[isleap(y)];
1095 for (y = 11; days < ip[y]; --y)
1099 tp->tm_mday = days + 1;
1102 /* Allocate a time zone string with given contents.
1103 The string will never be moved or deallocated.
1104 However, its contents may be shared with other such strings. */
1105 char *tzstring (const char* string)
1106 //const char *string;
1108 struct tzstring_head *h = &tzstring_list.head;
1112 /* Look through time zone string list for a duplicate of this one. */
1113 for (h = &tzstring_list.head; ; h = h->next)
1115 for (p = (char *) (h + 1); p[0] | p[1]; ++p)
1116 if (strcmp (p, string) == 0)
1122 /* No duplicate was found. Copy to the end of this buffer if there's room;
1123 otherwise, append a large-enough new buffer to the list and use it. */
1125 needed = strlen (string) + 2; /* Need 2 trailing '\0's after last string. */
1127 if ((size_t) ((char *) (h + 1) + tzstring_last_buffer_size - p) < needed)
1129 size_t buffer_size = tzstring_last_buffer_size;
1130 while ((buffer_size *= 2) < needed)
1132 if (! (h = h->next = (struct tzstring_head *)malloc (sizeof *h + buffer_size)))
1135 tzstring_last_buffer_size = buffer_size;
1136 p = (char *) (h + 1);
1139 return strncpy (p, string, needed);