1 /* Copyright (C) 1991, 92, 93, 94, 95, 96 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Library General Public License as
6 published by the Free Software Foundation; either version 2 of the
7 License, or (at your option) any later version.
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Library General Public License for more details.
14 You should have received a copy of the GNU Library General Public
15 License along with the GNU C Library; see the file COPYING.LIB. If
16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
17 Cambridge, MA 02139, USA. */
27 /* Defined in mktime.c. */
28 extern CONST
unsigned short int __mon_yday
[2][13];
33 extern int __use_tzfile
;
34 extern void EXFUN(__tzfile_read
, (CONST
char *file
));
35 extern void EXFUN(__tzfile_default
, (char *std AND
char *dst AND
36 long int stdoff AND
long int dstoff
));
37 extern int EXFUN(__tzfile_compute
, (time_t, struct tm
));
39 char *__tzname
[2] = { (char *) "GMT", (char *) "GMT" };
41 long int __timezone
= 0L;
43 weak_alias (__tzname
, tzname
)
44 weak_alias (__daylight
, daylight
)
45 weak_alias (__timezone
, timezone
)
48 #define min(a, b) ((a) < (b) ? (a) : (b))
49 #define max(a, b) ((a) > (b) ? (a) : (b))
50 #define sign(x) ((x) < 0 ? -1 : 1)
53 /* This structure contains all the information about a
54 timezone given in the POSIX standard TZ envariable. */
60 enum { J0
, J1
, M
} type
; /* Interpretation of: */
61 unsigned short int m
, n
, d
; /* Month, week, day. */
62 unsigned int secs
; /* Time of day. */
64 long int offset
; /* Seconds east of GMT (west if < 0). */
66 /* We cache the computed time of change for a
67 given year so we don't have to recompute it. */
68 time_t change
; /* When to change to this zone. */
69 int computed_for
; /* Year above is computed for. */
72 /* tz_rules[0] is standard, tz_rules[1] is daylight. */
73 static tz_rule tz_rules
[2];
77 /* Interpret the TZ envariable. */
81 register CONST
char *tz
;
83 unsigned short int hh
, mm
, ss
;
84 unsigned short int whichrule
;
86 /* Free old storage. */
87 if (tz_rules
[0].name
!= NULL
&& *tz_rules
[0].name
!= '\0')
89 free((PTR
) tz_rules
[0].name
);
90 tz_rules
[0].name
= NULL
;
92 if (tz_rules
[1].name
!= NULL
&& *tz_rules
[1].name
!= '\0' &&
93 tz_rules
[1].name
!= tz_rules
[0].name
)
95 free((PTR
) tz_rules
[1].name
);
96 tz_rules
[1].name
= NULL
;
99 /* Examine the TZ environment variable. */
102 /* A leading colon means "implementation defined syntax".
103 We ignore the colon and always use the same algorithm:
104 try a data file, and if none exists parse the 1003.1 syntax. */
105 if (tz
&& *tz
== ':')
108 /* Try to read a data file. */
116 /* No data file found. Default to UTC if nothing specified. */
118 if (tz
== NULL
|| *tz
== '\0')
120 static const char UTC
[] = "UTC";
121 size_t len
= sizeof UTC
;
122 tz_rules
[0].name
= (char *) malloc(len
);
123 if (tz_rules
[0].name
== NULL
)
125 tz_rules
[1].name
= (char *) malloc(len
);
126 if (tz_rules
[1].name
== NULL
)
128 memcpy ((PTR
) tz_rules
[0].name
, UTC
, len
);
129 memcpy ((PTR
) tz_rules
[1].name
, UTC
, len
);
130 tz_rules
[0].type
= tz_rules
[1].type
= J0
;
131 tz_rules
[0].m
= tz_rules
[0].n
= tz_rules
[0].d
= 0;
132 tz_rules
[1].m
= tz_rules
[1].n
= tz_rules
[1].d
= 0;
133 tz_rules
[0].secs
= tz_rules
[1].secs
= 0;
134 tz_rules
[0].offset
= tz_rules
[1].offset
= 0L;
135 tz_rules
[0].change
= tz_rules
[1].change
= (time_t) -1;
136 tz_rules
[0].computed_for
= tz_rules
[1].computed_for
= 0;
141 /* Clear out old state and reset to unnamed UTC. */
142 memset (tz_rules
, 0, sizeof tz_rules
);
143 tz_rules
[0].name
= tz_rules
[1].name
= (char *) "";
145 /* Get the standard timezone name. */
146 tz_rules
[0].name
= (char *) malloc (strlen (tz
) + 1);
147 if (tz_rules
[0].name
== NULL
)
148 /* Don't set __tzset_run so we will try again. */
151 if (sscanf(tz
, "%[^0-9,+-]", tz_rules
[0].name
) != 1 ||
152 (l
= strlen(tz_rules
[0].name
)) < 3)
154 free (tz_rules
[0].name
);
155 tz_rules
[0].name
= (char *) "";
160 char *n
= realloc ((PTR
) tz_rules
[0].name
, l
+ 1);
162 tz_rules
[0].name
= n
;
167 /* Figure out the standard offset from UTC. */
168 if (*tz
== '\0' || (*tz
!= '+' && *tz
!= '-' && !isdigit(*tz
)))
171 if (*tz
== '-' || *tz
== '+')
172 tz_rules
[0].offset
= *tz
++ == '-' ? 1L : -1L;
174 tz_rules
[0].offset
= -1L;
175 switch (sscanf (tz
, "%hu:%hu:%hu", &hh
, &mm
, &ss
))
186 tz_rules
[0].offset
*= (min(ss
, 59) + (min(mm
, 59) * 60) +
187 (min(hh
, 23) * 60 * 60));
189 for (l
= 0; l
< 3; ++l
)
193 if (l
< 2 && *tz
== ':')
197 /* Get the DST timezone name (if any). */
200 char *n
= malloc (strlen(tz
) + 1);
203 tz_rules
[1].name
= n
;
204 if (sscanf(tz
, "%[^0-9,+-]", tz_rules
[1].name
) != 1 ||
205 (l
= strlen(tz_rules
[1].name
)) < 3)
208 tz_rules
[1].name
= (char *) "";
209 goto done_names
; /* Punt on name, set up the offsets. */
211 n
= realloc ((PTR
) tz_rules
[1].name
, l
+ 1);
213 tz_rules
[1].name
= n
;
219 /* Figure out the DST offset from GMT. */
220 if (*tz
== '-' || *tz
== '+')
221 tz_rules
[1].offset
= *tz
++ == '-' ? 1L : -1L;
223 tz_rules
[1].offset
= -1L;
225 switch (sscanf (tz
, "%hu:%hu:%hu", &hh
, &mm
, &ss
))
228 /* Default to one hour later than standard time. */
229 tz_rules
[1].offset
= tz_rules
[0].offset
+ (60 * 60);
237 tz_rules
[1].offset
*= (min(ss
, 59) + (min(mm
, 59) * 60) +
238 (min(hh
, 23) * (60 * 60)));
241 for (l
= 0; l
< 3; ++l
)
243 while (isdigit (*tz
))
245 if (l
< 2 && *tz
== ':')
251 if (*tz
== '\0' || (tz
[0] == ',' && tz
[1] == '\0'))
253 /* There is no rule. See if there is a default rule file. */
254 __tzfile_default (tz_rules
[0].name
, tz_rules
[1].name
,
255 tz_rules
[0].offset
, tz_rules
[1].offset
);
263 /* Figure out the standard <-> DST rules. */
264 for (whichrule
= 0; whichrule
< 2; ++whichrule
)
266 register tz_rule
*tzr
= &tz_rules
[whichrule
];
275 /* Get the date of the change. */
276 if (*tz
== 'J' || isdigit (*tz
))
279 tzr
->type
= *tz
== 'J' ? J1
: J0
;
280 if (tzr
->type
== J1
&& !isdigit (*++tz
))
282 tzr
->d
= (unsigned short int) strtoul (tz
, &end
, 10);
283 if (end
== tz
|| tzr
->d
> 365)
285 else if (tzr
->type
== J1
&& tzr
->d
== 0)
293 if (sscanf (tz
, "M%hu.%hu.%hu%n",
294 &tzr
->m
, &tzr
->n
, &tzr
->d
, &n
) != 3 ||
295 tzr
->m
< 1 || tzr
->m
> 12 ||
296 tzr
->n
< 1 || tzr
->n
> 5 || tzr
->d
> 6)
300 else if (*tz
== '\0')
302 /* United States Federal Law, the equivalent of "M4.1.0,M10.5.0". */
304 if (tzr
== &tz_rules
[0])
320 if (*tz
!= '\0' && *tz
!= '/' && *tz
!= ',')
324 /* Get the time of day of the change. */
328 switch (sscanf (tz
, "%hu:%hu:%hu", &hh
, &mm
, &ss
))
331 hh
= 2; /* Default to 2:00 AM. */
339 for (l
= 0; l
< 3; ++l
)
343 if (l
< 2 && *tz
== ':')
346 tzr
->secs
= (hh
* 60 * 60) + (mm
* 60) + ss
;
349 /* Default to 2:00 AM. */
350 tzr
->secs
= 2 * 60 * 60;
352 tzr
->computed_for
= -1;
358 /* Maximum length of a timezone name. __tz_compute keeps this up to date
359 (never decreasing it) when ! __use_tzfile.
360 tzfile.c keeps it up to date when __use_tzfile. */
361 long int __tzname_cur_max
;
364 DEFUN_VOID(__tzname_max
)
369 return __tzname_cur_max
;
372 /* Figure out the exact time (as a time_t) in YEAR
373 when the change described by RULE will occur and
374 put it in RULE->change, saving YEAR in RULE->computed_for.
375 Return nonzero if successful, zero on failure. */
377 DEFUN(compute_change
, (rule
, year
), tz_rule
*rule AND
int year
)
382 if (year
!= -1 && rule
->computed_for
== year
)
383 /* Operations on times in 1969 will be slower. Oh well. */
386 /* First set T to January 1st, 0:00:00 GMT in YEAR. */
388 for (y
= 1970; y
< year
; ++y
)
389 t
+= SECSPERDAY
* (__isleap (y
) ? 366 : 365);
394 /* Jn - Julian day, 1 == January 1, 60 == March 1 even in leap years.
395 In non-leap years, or if the day number is 59 or less, just
396 add SECSPERDAY times the day number-1 to the time of
397 January 1, midnight, to get the day. */
398 t
+= (rule
->d
- 1) * SECSPERDAY
;
399 if (rule
->d
>= 60 && __isleap (year
))
405 Just add SECSPERDAY times the day number to the time of Jan 1st. */
406 t
+= rule
->d
* SECSPERDAY
;
410 /* Mm.n.d - Nth "Dth day" of month M. */
412 register int i
, d
, m1
, yy0
, yy1
, yy2
, dow
;
413 register CONST
unsigned short int *myday
=
414 &__mon_yday
[__isleap (year
)][rule
->m
];
416 /* First add SECSPERDAY for each day in months before M. */
417 t
+= myday
[-1] * SECSPERDAY
;
419 /* Use Zeller's Congruence to get day-of-week of first day of month. */
420 m1
= (rule
->m
+ 9) % 12 + 1;
421 yy0
= (rule
->m
<= 2) ? (year
- 1) : year
;
424 dow
= ((26 * m1
- 2) / 10 + 1 + yy2
+ yy2
/ 4 + yy1
/ 4 - 2 * yy1
) % 7;
428 /* DOW is the day-of-week of the first day of the month. Get the
429 day-of-month (zero-origin) of the first DOW day of the month. */
433 for (i
= 1; i
< rule
->n
; ++i
)
435 if (d
+ 7 >= myday
[0] - myday
[-1])
440 /* D is the day-of-month (zero-origin) of the day we want. */
446 /* T is now the Epoch-relative time of 0:00:00 GMT on the day we want.
447 Just add the time of day and local offset from GMT, and we're done. */
449 rule
->change
= t
+ rule
->offset
+ rule
->secs
;
450 rule
->computed_for
= year
;
455 /* Figure out the correct timezone for *TIMER and TM (which must be the same)
456 and set `__tzname', `__timezone', and `__daylight' accordingly.
457 Return nonzero on success, zero on failure. */
459 DEFUN(__tz_compute
, (timer
, tm
),
460 time_t timer AND
const struct tm
*tm
)
465 if (! compute_change (&tz_rules
[0], 1900 + tm
->tm_year
) ||
466 ! compute_change (&tz_rules
[1], 1900 + tm
->tm_year
))
469 __daylight
= timer
>= tz_rules
[0].change
&& timer
< tz_rules
[1].change
;
470 __timezone
= tz_rules
[__daylight
? 1 : 0].offset
;
471 __tzname
[0] = (char *) tz_rules
[0].name
;
472 __tzname
[1] = (char *) tz_rules
[1].name
;
475 /* Keep __tzname_cur_max up to date. */
476 size_t len0
= strlen (__tzname
[0]);
477 size_t len1
= strlen (__tzname
[1]);
478 if (len0
> __tzname_cur_max
)
479 __tzname_cur_max
= len0
;
480 if (len1
> __tzname_cur_max
)
481 __tzname_cur_max
= len1
;
487 #include <libc-lock.h>
489 /* This locks all the state variables in tzfile.c and this file. */
490 __libc_lock_define (, __tzset_lock
)
492 /* Reinterpret the TZ environment variable and set `tzname'. */
501 __libc_lock_lock (__tzset_lock
);
503 __libc_lock_unlock (__tzset_lock
);