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388 lines
10 KiB
C
388 lines
10 KiB
C
/* Copyright (C) 1991, 1992, 1993, 1995 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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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 in standard time. */
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unsigned char isgmt; /* Transition times are in GMT. */
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};
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struct leap
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{
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time_t transition; /* Time the transition takes effect. */
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long int change; /* Seconds of correction to apply. */
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};
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static void compute_tzname_max __P ((size_t));
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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, num_isgmt;
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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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num_isgmt = (size_t) uc2ul (tzhead.tzh_ttisgmtcnt);
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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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for (i = 0; i < num_isgmt; ++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].isgmt = c != 0;
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}
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while (i < num_types)
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types[i++].isgmt = 0;
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(void) fclose(f);
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compute_tzname_max (chars);
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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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/* The user specified a hand-made timezone, but not its DST rules.
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We will use the names and offsets from the user, and the rules
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from the TZDEFRULES file. */
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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, i;
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long int rule_offset, rule_stdoff, rule_dstoff;
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int isdst;
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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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/* Ignore the zone names read from the file. */
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free (zone_names);
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/* Use the names the user specified. */
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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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/* Find the standard and daylight time offsets used by the rule file.
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We choose the offsets in the types of each flavor that are
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transitioned to earliest in time. */
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rule_dstoff = 0;
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for (i = 0; i < num_transitions; ++i)
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{
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if (!rule_stdoff && !types[type_idxs[i]].isdst)
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rule_stdoff = types[type_idxs[i]].offset;
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if (!rule_dstoff && types[type_idxs[i]].isdst)
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rule_dstoff = types[type_idxs[i]].offset;
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if (rule_stdoff && rule_dstoff)
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break;
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}
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/* Now correct the transition times for the user-specified standard and
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daylight offsets from GMT. */
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isdst = 0;
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rule_offset = rule_offset;
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for (i = 0; i < num_transitions; ++i)
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{
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struct ttinfo *trans_type = &types[type_idxs[i]];
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/* We will use only types 0 (standard) and 1 (daylight).
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Fix up this transition to point to whichever matches
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the flavor of its original type. */
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type_idxs[i] = trans_type->isdst;
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if (trans_type->isgmt)
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/* The transition time is in GMT. No correction to apply. */ ;
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else if (isdst && !trans_type->isstd)
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/* The type says this transition is in "local wall clock time", and
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wall clock time as of the previous transition was DST. Correct
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for the difference between the rule's DST offset and the user's
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DST offset. */
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transitions[i] += dstoff - rule_dstoff;
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else
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/* This transition is in "local wall clock time", and wall clock
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time as of this iteration is non-DST. Correct for the
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difference between the rule's standard offset and the user's
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standard offset. */
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transitions[i] += stdoff - rule_stdoff;
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/* The DST state of "local wall clock time" for the next iteration is
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as specified by this transition. */
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isdst = trans_type->isdst;
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}
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/* Reset types 0 and 1 to describe the user's settings. */
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types[0].idx = 0;
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types[0].offset = stdoff;
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types[0].isdst = 0;
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types[1].idx = stdlen;
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types[1].offset = dstoff;
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types[1].isdst = 1;
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compute_tzname_max (stdlen + dstlen);
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}
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int
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DEFUN(__tzfile_compute, (timer, leap_correct, leap_hit),
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time_t timer AND long int *leap_correct AND int *leap_hit)
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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
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then pick the type of the transition before it. */
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for (i = 1; i < num_transitions; ++i)
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if (timer < transitions[i])
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break;
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i = type_idxs[i - 1];
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}
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info = &types[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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*leap_correct = 0L;
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*leap_hit = 0;
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/* Find the last leap second correction transition time before TIMER. */
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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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/* Apply its correction. */
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*leap_correct = leaps[i].change;
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if (timer == leaps[i].transition && /* Exactly at the transition time. */
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((i == 0 && leaps[i].change > 0) ||
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leaps[i].change > leaps[i - 1].change))
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{
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*leap_hit = 1;
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while (i > 0 &&
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leaps[i].transition == leaps[i - 1].transition + 1 &&
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leaps[i].change == leaps[i - 1].change + 1)
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{
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++*leap_hit;
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--i;
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}
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}
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return 1;
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}
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void
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DEFUN(compute_tzname_max, (chars), size_t chars)
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{
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extern long int __tzname_cur_max; /* Defined in __tzset.c. */
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const char *p;
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p = zone_names;
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do
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{
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const char *start = p;
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while (*p != '\0')
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++p;
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if (p - start > __tzname_cur_max)
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__tzname_cur_max = p - start;
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} while (++p < &zone_names[chars]);
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}
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