280 lines
6.7 KiB
C
280 lines
6.7 KiB
C
/* Copyright (C) 1991, 1992 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
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not, write to the Free Software Foundation, Inc., 675 Mass Ave,
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Cambridge, MA 02139, USA. */
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#include <ansidecl.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <time.h>
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#include <string.h>
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#include <limits.h>
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#define NOID
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#include <tzfile.h>
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#ifndef HAVE_GNU_LD
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#define __tzname tzname
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#define __daylight daylight
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#define __timezone timezone
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#endif
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int __use_tzfile = 0;
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struct ttinfo
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{
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long int offset; /* Seconds east of GMT. */
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unsigned char isdst; /* Used to set tm_isdst. */
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unsigned char idx; /* Index into `zone_names'. */
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unsigned char isstd; /* Transition times are standard time. */
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};
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struct leap
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{
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time_t transition;
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long int change;
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};
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static size_t num_transitions;
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static time_t *transitions = NULL;
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static unsigned char *type_idxs = NULL;
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static size_t num_types;
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static struct ttinfo *types = NULL;
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static char *zone_names = NULL;
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static size_t num_leaps;
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static struct leap *leaps = NULL;
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#define uc2ul(x) _uc2ul((unsigned char *) (x))
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#define _uc2ul(x) \
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((x)[3] + ((x)[2] << CHAR_BIT) + ((x)[1] << (2 * CHAR_BIT)) + \
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((x)[0] << (3 * CHAR_BIT)))
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void
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DEFUN(__tzfile_read, (file), CONST char *file)
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{
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size_t num_isstd;
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register FILE *f;
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struct tzhead tzhead;
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size_t chars;
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register size_t i;
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__use_tzfile = 0;
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if (transitions != NULL)
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free((PTR) transitions);
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transitions = NULL;
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if (type_idxs != NULL)
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free((PTR) type_idxs);
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type_idxs = NULL;
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if (types != NULL)
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free((PTR) types);
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types = NULL;
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if (zone_names != NULL)
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free((PTR) zone_names);
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zone_names = NULL;
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if (leaps != NULL)
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free((PTR) leaps);
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leaps = NULL;
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if (file == NULL || *file == '\0')
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file = TZDEFAULT;
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if (*file != '/')
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{
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static CONST char tzdir[] = TZDIR;
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register CONST unsigned int len = strlen(file) + 1;
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char *new = (char *) __alloca(sizeof(tzdir) + len);
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memcpy(new, tzdir, sizeof(tzdir) - 1);
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new[sizeof(tzdir) - 1] = '/';
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memcpy(&new[sizeof(tzdir)], file, len);
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file = new;
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}
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f = fopen(file, "r");
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if (f == NULL)
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return;
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if (fread((PTR) &tzhead, sizeof(tzhead), 1, f) != 1)
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goto lose;
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num_transitions = (size_t) uc2ul(tzhead.tzh_timecnt);
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num_types = (size_t) uc2ul(tzhead.tzh_typecnt);
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chars = (size_t) uc2ul(tzhead.tzh_charcnt);
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num_leaps = (size_t) uc2ul(tzhead.tzh_leapcnt);
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num_isstd = (size_t) uc2ul(tzhead.tzh_ttisstdcnt);
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if (num_transitions > 0)
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{
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transitions = (time_t *) malloc (num_transitions * sizeof(time_t));
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if (transitions == NULL)
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goto lose;
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type_idxs = (unsigned char *) malloc (num_transitions);
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if (type_idxs == NULL)
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goto lose;
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}
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if (num_types > 0)
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{
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types = (struct ttinfo *) malloc (num_types * sizeof (struct ttinfo));
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if (types == NULL)
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goto lose;
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}
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if (chars > 0)
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{
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zone_names = (char *) malloc (chars);
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if (zone_names == NULL)
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goto lose;
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}
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if (num_leaps > 0)
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{
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leaps = (struct leap *) malloc (num_leaps * sizeof (struct leap));
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if (leaps == NULL)
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goto lose;
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}
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if (fread((PTR) transitions, sizeof(time_t),
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num_transitions, f) != num_transitions ||
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fread((PTR) type_idxs, 1, num_transitions, f) != num_transitions)
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goto lose;
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for (i = 0; i < num_transitions; ++i)
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transitions[i] = uc2ul (&transitions[i]);
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for (i = 0; i < num_types; ++i)
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{
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unsigned char x[4];
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if (fread((PTR) x, 1, 4, f) != 4 ||
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fread((PTR) &types[i].isdst, 1, 1, f) != 1 ||
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fread((PTR) &types[i].idx, 1, 1, f) != 1)
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goto lose;
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types[i].offset = (long int) uc2ul(x);
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}
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if (fread((PTR) zone_names, 1, chars, f) != chars)
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goto lose;
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for (i = 0; i < num_leaps; ++i)
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{
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unsigned char x[4];
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if (fread((PTR) x, 1, sizeof(x), f) != sizeof(x))
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goto lose;
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leaps[i].transition = (time_t) uc2ul(x);
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if (fread((PTR) x, 1, sizeof(x), f) != sizeof(x))
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goto lose;
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leaps[i].change = (long int) uc2ul(x);
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}
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for (i = 0; i < num_isstd; ++i)
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{
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char c = getc(f);
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if (c == EOF)
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goto lose;
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types[i].isstd = c != 0;
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}
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while (i < num_types)
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types[i++].isstd = 0;
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(void) fclose(f);
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__use_tzfile = 1;
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return;
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lose:;
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(void) fclose(f);
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}
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void
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DEFUN(__tzfile_default, (std, dst, stdoff, dstoff),
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char *std AND char *dst AND
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long int stdoff AND long int dstoff)
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{
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size_t stdlen, dstlen;
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__tzfile_read (TZDEFRULES);
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if (!__use_tzfile)
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return;
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if (num_types != 2)
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{
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__use_tzfile = 0;
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return;
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}
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free (zone_names);
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stdlen = strlen (std) + 1;
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dstlen = strlen (dst) + 1;
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zone_names = malloc (stdlen + dstlen);
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if (zone_names == NULL)
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{
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__use_tzfile = 0;
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return;
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}
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memcpy (zone_names, std, stdlen);
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memcpy (&zone_names[stdlen], dst, dstlen);
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types[0].idx = 0;
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types[0].isdst = 0;
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if (std[0] != '\0')
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types[0].offset = stdoff;
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types[1].idx = stdlen;
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types[1].isdst = 1;
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if (dst[0] != '\0')
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types[1].offset = dstoff;
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}
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int
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DEFUN(__tzfile_compute, (timer, tm), time_t timer AND struct tm tm)
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{
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struct ttinfo *info;
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register size_t i;
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if (num_transitions == 0 || timer < transitions[0])
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{
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/* TIMER is before any transition (or there are no transitions).
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Choose the first non-DST type
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(or the first if they're all DST types). */
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i = 0;
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while (i < num_types && types[i].isdst)
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++i;
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if (i == num_types)
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i = 0;
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}
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else
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{
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/* Find the first transition after TIMER, and then go back one. */
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i = 1;
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while (i < num_transitions && transitions[i] < timer)
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++i;
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--i;
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}
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info = &types[type_idxs[i]];
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__daylight = info->isdst;
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__timezone = info->offset;
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for (i = 0; i < num_types && i < sizeof (__tzname) / sizeof (__tzname[0]);
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++i)
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__tzname[types[i].isdst] = &zone_names[types[i].idx];
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if (info->isdst < sizeof (__tzname) / sizeof (__tzname[0]))
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__tzname[info->isdst] = &zone_names[info->idx];
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i = num_leaps;
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do
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if (i-- == 0)
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return 1;
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while (timer < leaps[i].transition);
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__timezone += leaps[i].change;
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return 1;
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}
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