650 lines
16 KiB
C
650 lines
16 KiB
C
/* Copyright (C) 1991, 92, 93, 94, 95, 96, 97 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include <ctype.h>
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#include <errno.h>
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#include <bits/libc-lock.h>
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#include <stddef.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <time.h>
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/* Defined in mktime.c. */
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extern const unsigned short int __mon_yday[2][13];
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/* Defined in localtime.c. */
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extern struct tm _tmbuf;
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#define NOID
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#include "tzfile.h"
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extern int __use_tzfile;
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extern void __tzfile_read __P ((const char *file));
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extern int __tzfile_compute __P ((time_t timer, int use_localtime,
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long int *leap_correct, int *leap_hit));
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extern void __tzfile_default __P ((const char *std, const char *dst,
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long int stdoff, long int dstoff));
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extern char * __tzstring __P ((const char *string));
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char *__tzname[2] = { (char *) "GMT", (char *) "GMT" };
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int __daylight = 0;
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long int __timezone = 0L;
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weak_alias (__tzname, tzname)
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weak_alias (__daylight, daylight)
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weak_alias (__timezone, timezone)
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/* This locks all the state variables in tzfile.c and this file. */
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__libc_lock_define (static, tzset_lock)
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#define min(a, b) ((a) < (b) ? (a) : (b))
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#define max(a, b) ((a) > (b) ? (a) : (b))
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#define sign(x) ((x) < 0 ? -1 : 1)
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/* This structure contains all the information about a
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timezone given in the POSIX standard TZ envariable. */
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typedef struct
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{
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const char *name;
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/* When to change. */
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enum { J0, J1, M } type; /* Interpretation of: */
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unsigned short int m, n, d; /* Month, week, day. */
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unsigned int secs; /* Time of day. */
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long int offset; /* Seconds east of GMT (west if < 0). */
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/* We cache the computed time of change for a
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given year so we don't have to recompute it. */
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time_t change; /* When to change to this zone. */
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int computed_for; /* Year above is computed for. */
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} tz_rule;
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/* tz_rules[0] is standard, tz_rules[1] is daylight. */
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static tz_rule tz_rules[2];
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static int compute_change __P ((tz_rule *rule, int year)) internal_function;
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static int tz_compute __P ((time_t timer, const struct tm *tm))
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internal_function;
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static void tzset_internal __P ((int always)) internal_function;
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/* Header for a list of buffers containing time zone strings. */
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struct tzstring_head
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{
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struct tzstring_head *next;
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/* The buffer itself immediately follows the header.
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The buffer contains zero or more (possibly overlapping) strings.
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The last string is followed by 2 '\0's instead of the usual 1. */
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};
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/* First in a list of buffers containing time zone strings.
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All the buffers but the last are read-only. */
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static struct
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{
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struct tzstring_head head;
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char data[48];
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} tzstring_list;
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/* Size of the last buffer in the list, not counting its header. */
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static size_t tzstring_last_buffer_size = sizeof tzstring_list.data;
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/* Allocate a time zone string with given contents.
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The string will never be moved or deallocated.
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However, its contents may be shared with other such strings. */
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char *
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__tzstring (string)
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const char *string;
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{
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struct tzstring_head *h = &tzstring_list.head;
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size_t needed;
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char *p;
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/* Look through time zone string list for a duplicate of this one. */
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for (h = &tzstring_list.head; ; h = h->next)
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{
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for (p = (char *) (h + 1); p[0] | p[1]; ++p)
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if (strcmp (p, string) == 0)
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return p;
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if (! h->next)
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break;
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}
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/* No duplicate was found. Copy to the end of this buffer if there's room;
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otherwise, append a large-enough new buffer to the list and use it. */
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++p;
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needed = strlen (string) + 2; /* Need 2 trailing '\0's after last string. */
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if ((size_t) ((char *) (h + 1) + tzstring_last_buffer_size - p) < needed)
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{
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size_t buffer_size = tzstring_last_buffer_size;
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while ((buffer_size *= 2) < needed)
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continue;
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if (! (h = h->next = malloc (sizeof *h + buffer_size)))
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return NULL;
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h->next = NULL;
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tzstring_last_buffer_size = buffer_size;
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p = (char *) (h + 1);
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}
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return strncpy (p, string, needed);
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}
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static char *old_tz = NULL;
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/* Interpret the TZ envariable. */
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static void
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internal_function
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tzset_internal (always)
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int always;
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{
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static int is_initialized = 0;
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register const char *tz;
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register size_t l;
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char *tzbuf;
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unsigned short int hh, mm, ss;
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unsigned short int whichrule;
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if (is_initialized && !always)
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return;
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is_initialized = 1;
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/* Examine the TZ environment variable. */
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tz = getenv ("TZ");
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if (tz == NULL)
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/* No user specification; use the site-wide default. */
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tz = TZDEFAULT;
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else if (*tz == '\0')
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/* User specified the empty string; use UTC explicitly. */
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tz = "Universal";
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/* A leading colon means "implementation defined syntax".
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We ignore the colon and always use the same algorithm:
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try a data file, and if none exists parse the 1003.1 syntax. */
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if (tz && *tz == ':')
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++tz;
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/* Check whether the value changes since the last run. */
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if (old_tz != NULL && tz != NULL && strcmp (tz, old_tz) == 0)
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/* No change, simply return. */
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return;
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tz_rules[0].name = NULL;
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tz_rules[1].name = NULL;
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/* Save the value of `tz'. */
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if (old_tz != NULL)
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free (old_tz);
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old_tz = tz ? __strdup (tz) : NULL;
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/* Try to read a data file. */
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__tzfile_read (tz);
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if (__use_tzfile)
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return;
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/* No data file found. Default to UTC if nothing specified. */
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if (tz == NULL || *tz == '\0')
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{
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tz_rules[0].name = tz_rules[1].name = "UTC";
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tz_rules[0].type = tz_rules[1].type = J0;
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tz_rules[0].m = tz_rules[0].n = tz_rules[0].d = 0;
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tz_rules[1].m = tz_rules[1].n = tz_rules[1].d = 0;
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tz_rules[0].secs = tz_rules[1].secs = 0;
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tz_rules[0].offset = tz_rules[1].offset = 0L;
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tz_rules[0].change = tz_rules[1].change = (time_t) -1;
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tz_rules[0].computed_for = tz_rules[1].computed_for = 0;
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return;
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}
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/* Clear out old state and reset to unnamed UTC. */
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memset (tz_rules, 0, sizeof tz_rules);
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tz_rules[0].name = tz_rules[1].name = "";
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/* Get the standard timezone name. */
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tzbuf = malloc (strlen (tz) + 1);
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if (! tzbuf)
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{
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/* Clear the old tz name so we will try again. */
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free (old_tz);
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old_tz = NULL;
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return;
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}
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if (sscanf (tz, "%[^0-9,+-]", tzbuf) != 1 ||
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(l = strlen (tzbuf)) < 3)
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{
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free (tzbuf);
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return;
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}
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tz_rules[0].name = __tzstring (tzbuf);
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tz += l;
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/* Figure out the standard offset from UTC. */
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if (*tz == '\0' || (*tz != '+' && *tz != '-' && !isdigit (*tz)))
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{
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free (tzbuf);
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return;
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}
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if (*tz == '-' || *tz == '+')
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tz_rules[0].offset = *tz++ == '-' ? 1L : -1L;
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else
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tz_rules[0].offset = -1L;
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switch (sscanf (tz, "%hu:%hu:%hu", &hh, &mm, &ss))
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{
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default:
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free (tzbuf);
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return;
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case 1:
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mm = 0;
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case 2:
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ss = 0;
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case 3:
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break;
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}
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tz_rules[0].offset *= (min (ss, 59) + (min (mm, 59) * 60) +
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(min (hh, 23) * 60 * 60));
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for (l = 0; l < 3; ++l)
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{
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while (isdigit(*tz))
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++tz;
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if (l < 2 && *tz == ':')
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++tz;
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}
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/* Get the DST timezone name (if any). */
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if (*tz != '\0')
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{
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char *n = tzbuf + strlen (tzbuf) + 1;
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if (sscanf (tz, "%[^0-9,+-]", n) != 1 ||
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(l = strlen (n)) < 3)
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goto done_names; /* Punt on name, set up the offsets. */
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tz_rules[1].name = __tzstring (n);
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tz += l;
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/* Figure out the DST offset from GMT. */
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if (*tz == '-' || *tz == '+')
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tz_rules[1].offset = *tz++ == '-' ? 1L : -1L;
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else
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tz_rules[1].offset = -1L;
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switch (sscanf (tz, "%hu:%hu:%hu", &hh, &mm, &ss))
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{
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default:
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/* Default to one hour later than standard time. */
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tz_rules[1].offset = tz_rules[0].offset + (60 * 60);
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break;
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case 1:
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mm = 0;
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case 2:
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ss = 0;
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case 3:
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tz_rules[1].offset *= (min (ss, 59) + (min (mm, 59) * 60) +
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(min (hh, 23) * (60 * 60)));
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break;
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}
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for (l = 0; l < 3; ++l)
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{
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while (isdigit (*tz))
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++tz;
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if (l < 2 && *tz == ':')
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++tz;
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}
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if (*tz == '\0' || (tz[0] == ',' && tz[1] == '\0'))
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{
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/* There is no rule. See if there is a default rule file. */
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__tzfile_default (tz_rules[0].name, tz_rules[1].name,
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tz_rules[0].offset, tz_rules[1].offset);
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if (__use_tzfile)
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{
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free (old_tz);
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old_tz = NULL;
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free (tzbuf);
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return;
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}
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}
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}
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else
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{
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/* There is no DST. */
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tz_rules[1].name = tz_rules[0].name;
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free (tzbuf);
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return;
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}
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done_names:
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free (tzbuf);
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/* Figure out the standard <-> DST rules. */
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for (whichrule = 0; whichrule < 2; ++whichrule)
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{
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register tz_rule *tzr = &tz_rules[whichrule];
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/* Ignore comma to support string following the incorrect
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specification in early POSIX.1 printings. */
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tz += *tz == ',';
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/* Get the date of the change. */
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if (*tz == 'J' || isdigit (*tz))
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{
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char *end;
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tzr->type = *tz == 'J' ? J1 : J0;
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if (tzr->type == J1 && !isdigit (*++tz))
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return;
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tzr->d = (unsigned short int) strtoul (tz, &end, 10);
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if (end == tz || tzr->d > 365)
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return;
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else if (tzr->type == J1 && tzr->d == 0)
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return;
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tz = end;
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}
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else if (*tz == 'M')
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{
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int n;
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tzr->type = M;
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if (sscanf (tz, "M%hu.%hu.%hu%n",
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&tzr->m, &tzr->n, &tzr->d, &n) != 3 ||
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tzr->m < 1 || tzr->m > 12 ||
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tzr->n < 1 || tzr->n > 5 || tzr->d > 6)
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return;
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tz += n;
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}
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else if (*tz == '\0')
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{
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/* United States Federal Law, the equivalent of "M4.1.0,M10.5.0". */
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tzr->type = M;
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if (tzr == &tz_rules[0])
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{
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tzr->m = 4;
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tzr->n = 1;
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tzr->d = 0;
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}
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else
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{
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tzr->m = 10;
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tzr->n = 5;
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tzr->d = 0;
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}
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}
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else
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return;
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if (*tz != '\0' && *tz != '/' && *tz != ',')
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return;
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else if (*tz == '/')
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{
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/* Get the time of day of the change. */
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++tz;
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if (*tz == '\0')
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return;
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switch (sscanf (tz, "%hu:%hu:%hu", &hh, &mm, &ss))
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{
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default:
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hh = 2; /* Default to 2:00 AM. */
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case 1:
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mm = 0;
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case 2:
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ss = 0;
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case 3:
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break;
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}
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for (l = 0; l < 3; ++l)
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{
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while (isdigit (*tz))
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++tz;
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if (l < 2 && *tz == ':')
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++tz;
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}
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tzr->secs = (hh * 60 * 60) + (mm * 60) + ss;
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}
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else
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/* Default to 2:00 AM. */
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tzr->secs = 2 * 60 * 60;
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tzr->computed_for = -1;
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}
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}
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/* Maximum length of a timezone name. __tz_compute keeps this up to date
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(never decreasing it) when ! __use_tzfile.
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tzfile.c keeps it up to date when __use_tzfile. */
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size_t __tzname_cur_max;
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long int
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__tzname_max ()
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{
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__libc_lock_lock (tzset_lock);
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tzset_internal (0);
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__libc_lock_unlock (tzset_lock);
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return __tzname_cur_max;
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}
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/* Figure out the exact time (as a time_t) in YEAR
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when the change described by RULE will occur and
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put it in RULE->change, saving YEAR in RULE->computed_for.
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Return nonzero if successful, zero on failure. */
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static int
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internal_function
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compute_change (rule, year)
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tz_rule *rule;
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int year;
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{
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register time_t t;
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int y;
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if (year != -1 && rule->computed_for == year)
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/* Operations on times in 1969 will be slower. Oh well. */
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return 1;
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/* First set T to January 1st, 0:00:00 GMT in YEAR. */
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t = 0;
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for (y = 1970; y < year; ++y)
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t += SECSPERDAY * (__isleap (y) ? 366 : 365);
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switch (rule->type)
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{
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case J1:
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/* Jn - Julian day, 1 == January 1, 60 == March 1 even in leap years.
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In non-leap years, or if the day number is 59 or less, just
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add SECSPERDAY times the day number-1 to the time of
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January 1, midnight, to get the day. */
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t += (rule->d - 1) * SECSPERDAY;
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if (rule->d >= 60 && __isleap (year))
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t += SECSPERDAY;
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break;
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case J0:
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/* n - Day of year.
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Just add SECSPERDAY times the day number to the time of Jan 1st. */
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t += rule->d * SECSPERDAY;
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break;
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case M:
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/* Mm.n.d - Nth "Dth day" of month M. */
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{
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unsigned int i;
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int d, m1, yy0, yy1, yy2, dow;
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const unsigned short int *myday =
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&__mon_yday[__isleap (year)][rule->m];
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/* First add SECSPERDAY for each day in months before M. */
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t += myday[-1] * SECSPERDAY;
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/* Use Zeller's Congruence to get day-of-week of first day of month. */
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m1 = (rule->m + 9) % 12 + 1;
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yy0 = (rule->m <= 2) ? (year - 1) : year;
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yy1 = yy0 / 100;
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yy2 = yy0 % 100;
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dow = ((26 * m1 - 2) / 10 + 1 + yy2 + yy2 / 4 + yy1 / 4 - 2 * yy1) % 7;
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if (dow < 0)
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dow += 7;
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/* DOW is the day-of-week of the first day of the month. Get the
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day-of-month (zero-origin) of the first DOW day of the month. */
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d = rule->d - dow;
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if (d < 0)
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d += 7;
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for (i = 1; i < rule->n; ++i)
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{
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if (d + 7 >= (int) myday[0] - myday[-1])
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break;
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d += 7;
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}
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/* D is the day-of-month (zero-origin) of the day we want. */
|
||
t += d * SECSPERDAY;
|
||
}
|
||
break;
|
||
}
|
||
|
||
/* T is now the Epoch-relative time of 0:00:00 GMT on the day we want.
|
||
Just add the time of day and local offset from GMT, and we're done. */
|
||
|
||
rule->change = t - rule->offset + rule->secs;
|
||
rule->computed_for = year;
|
||
return 1;
|
||
}
|
||
|
||
|
||
/* Figure out the correct timezone for *TIMER and TM (which must be the same)
|
||
and set `__tzname', `__timezone', and `__daylight' accordingly.
|
||
Return nonzero on success, zero on failure. */
|
||
static int
|
||
internal_function
|
||
tz_compute (timer, tm)
|
||
time_t timer;
|
||
const struct tm *tm;
|
||
{
|
||
if (! compute_change (&tz_rules[0], 1900 + tm->tm_year) ||
|
||
! compute_change (&tz_rules[1], 1900 + tm->tm_year))
|
||
return 0;
|
||
|
||
__daylight = timer >= tz_rules[0].change && timer < tz_rules[1].change;
|
||
__timezone = -tz_rules[__daylight].offset;
|
||
__tzname[0] = (char *) tz_rules[0].name;
|
||
__tzname[1] = (char *) tz_rules[1].name;
|
||
|
||
{
|
||
/* Keep __tzname_cur_max up to date. */
|
||
size_t len0 = strlen (__tzname[0]);
|
||
size_t len1 = strlen (__tzname[1]);
|
||
if (len0 > __tzname_cur_max)
|
||
__tzname_cur_max = len0;
|
||
if (len1 > __tzname_cur_max)
|
||
__tzname_cur_max = len1;
|
||
}
|
||
|
||
return 1;
|
||
}
|
||
|
||
/* Reinterpret the TZ environment variable and set `tzname'. */
|
||
#undef tzset
|
||
|
||
void
|
||
__tzset (void)
|
||
{
|
||
__libc_lock_lock (tzset_lock);
|
||
|
||
tzset_internal (1);
|
||
|
||
if (!__use_tzfile)
|
||
{
|
||
/* Set `tzname'. */
|
||
__tzname[0] = (char *) tz_rules[0].name;
|
||
__tzname[1] = (char *) tz_rules[1].name;
|
||
}
|
||
|
||
__libc_lock_unlock (tzset_lock);
|
||
}
|
||
weak_alias (__tzset, tzset)
|
||
|
||
/* Return the `struct tm' representation of *TIMER in the local timezone.
|
||
Use local time if USE_LOCALTIME is nonzero, UTC otherwise. */
|
||
struct tm *
|
||
__tz_convert (const time_t *timer, int use_localtime, struct tm *tp)
|
||
{
|
||
long int leap_correction;
|
||
int leap_extra_secs;
|
||
|
||
if (timer == NULL)
|
||
{
|
||
__set_errno (EINVAL);
|
||
return NULL;
|
||
}
|
||
|
||
__libc_lock_lock (tzset_lock);
|
||
|
||
/* Update internal database according to current TZ setting.
|
||
POSIX.1 8.3.7.2 says that localtime_r is not required to set tzname.
|
||
This is a good idea since this allows at least a bit more parallelism.
|
||
By analogy we apply the same rule to gmtime_r. */
|
||
tzset_internal (tp == &_tmbuf);
|
||
|
||
if (__use_tzfile)
|
||
{
|
||
if (! __tzfile_compute (*timer, use_localtime,
|
||
&leap_correction, &leap_extra_secs))
|
||
tp = NULL;
|
||
}
|
||
else
|
||
{
|
||
if (! (__offtime (timer, 0, tp) && tz_compute (*timer, tp)))
|
||
tp = NULL;
|
||
leap_correction = 0L;
|
||
leap_extra_secs = 0;
|
||
}
|
||
|
||
if (tp)
|
||
{
|
||
if (use_localtime)
|
||
{
|
||
tp->tm_isdst = __daylight;
|
||
tp->tm_zone = __tzname[__daylight];
|
||
tp->tm_gmtoff = -__timezone;
|
||
}
|
||
else
|
||
{
|
||
tp->tm_isdst = 0;
|
||
tp->tm_zone = "GMT";
|
||
tp->tm_gmtoff = 0L;
|
||
}
|
||
|
||
if (__offtime (timer, tp->tm_gmtoff - leap_correction, tp))
|
||
tp->tm_sec += leap_extra_secs;
|
||
else
|
||
tp = NULL;
|
||
}
|
||
|
||
__libc_lock_unlock (tzset_lock);
|
||
|
||
return tp;
|
||
}
|