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authorRoland McGrath <roland@gnu.org>1995-02-18 01:27:10 +0000
committerRoland McGrath <roland@gnu.org>1995-02-18 01:27:10 +0000
commit28f540f45bbacd939bfd07f213bcad2bf730b1bf (patch)
tree15f07c4c43d635959c6afee96bde71fb1b3614ee /time/tzfile.c
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initial import
Diffstat (limited to 'time/tzfile.c')
-rw-r--r--time/tzfile.c332
1 files changed, 332 insertions, 0 deletions
diff --git a/time/tzfile.c b/time/tzfile.c
new file mode 100644
index 0000000000..841f598c87
--- /dev/null
+++ b/time/tzfile.c
@@ -0,0 +1,332 @@
+/* Copyright (C) 1991, 1992, 1993 Free Software Foundation, Inc.
+This file is part of the GNU C Library.
+
+The GNU C Library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public License as
+published by the Free Software Foundation; either version 2 of the
+License, or (at your option) any later version.
+
+The GNU C Library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with the GNU C Library; see the file COPYING.LIB. If
+not, write to the Free Software Foundation, Inc., 675 Mass Ave,
+Cambridge, MA 02139, USA. */
+
+#include <ansidecl.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <time.h>
+#include <string.h>
+#include <limits.h>
+
+#define NOID
+#include <tzfile.h>
+
+#ifndef HAVE_GNU_LD
+#define __tzname tzname
+#define __daylight daylight
+#define __timezone timezone
+#endif
+
+int __use_tzfile = 0;
+
+struct ttinfo
+ {
+ long int offset; /* Seconds east of GMT. */
+ unsigned char isdst; /* Used to set tm_isdst. */
+ unsigned char idx; /* Index into `zone_names'. */
+ unsigned char isstd; /* Transition times are standard time. */
+ };
+
+struct leap
+ {
+ time_t transition; /* Time the transition takes effect. */
+ long int change; /* Seconds of correction to apply. */
+ };
+
+static void compute_tzname_max __P ((size_t));
+
+static size_t num_transitions;
+static time_t *transitions = NULL;
+static unsigned char *type_idxs = NULL;
+static size_t num_types;
+static struct ttinfo *types = NULL;
+static char *zone_names = NULL;
+static size_t num_leaps;
+static struct leap *leaps = NULL;
+
+#define uc2ul(x) _uc2ul((unsigned char *) (x))
+#define _uc2ul(x) \
+ ((x)[3] + ((x)[2] << CHAR_BIT) + ((x)[1] << (2 * CHAR_BIT)) + \
+ ((x)[0] << (3 * CHAR_BIT)))
+
+void
+DEFUN(__tzfile_read, (file), CONST char *file)
+{
+ size_t num_isstd;
+ register FILE *f;
+ struct tzhead tzhead;
+ size_t chars;
+ register size_t i;
+
+ __use_tzfile = 0;
+
+ if (transitions != NULL)
+ free((PTR) transitions);
+ transitions = NULL;
+ if (type_idxs != NULL)
+ free((PTR) type_idxs);
+ type_idxs = NULL;
+ if (types != NULL)
+ free((PTR) types);
+ types = NULL;
+ if (zone_names != NULL)
+ free((PTR) zone_names);
+ zone_names = NULL;
+ if (leaps != NULL)
+ free((PTR) leaps);
+ leaps = NULL;
+
+ if (file == NULL || *file == '\0')
+ file = TZDEFAULT;
+
+ if (*file != '/')
+ {
+ static CONST char tzdir[] = TZDIR;
+ register CONST unsigned int len = strlen(file) + 1;
+ char *new = (char *) __alloca(sizeof(tzdir) + len);
+ memcpy(new, tzdir, sizeof(tzdir) - 1);
+ new[sizeof(tzdir) - 1] = '/';
+ memcpy(&new[sizeof(tzdir)], file, len);
+ file = new;
+ }
+
+ f = fopen(file, "r");
+ if (f == NULL)
+ return;
+
+ if (fread((PTR) &tzhead, sizeof(tzhead), 1, f) != 1)
+ goto lose;
+
+ num_transitions = (size_t) uc2ul(tzhead.tzh_timecnt);
+ num_types = (size_t) uc2ul(tzhead.tzh_typecnt);
+ chars = (size_t) uc2ul(tzhead.tzh_charcnt);
+ num_leaps = (size_t) uc2ul(tzhead.tzh_leapcnt);
+ num_isstd = (size_t) uc2ul(tzhead.tzh_ttisstdcnt);
+
+ if (num_transitions > 0)
+ {
+ transitions = (time_t *) malloc (num_transitions * sizeof(time_t));
+ if (transitions == NULL)
+ goto lose;
+ type_idxs = (unsigned char *) malloc (num_transitions);
+ if (type_idxs == NULL)
+ goto lose;
+ }
+ if (num_types > 0)
+ {
+ types = (struct ttinfo *) malloc (num_types * sizeof (struct ttinfo));
+ if (types == NULL)
+ goto lose;
+ }
+ if (chars > 0)
+ {
+ zone_names = (char *) malloc (chars);
+ if (zone_names == NULL)
+ goto lose;
+ }
+ if (num_leaps > 0)
+ {
+ leaps = (struct leap *) malloc (num_leaps * sizeof (struct leap));
+ if (leaps == NULL)
+ goto lose;
+ }
+
+ if (fread((PTR) transitions, sizeof(time_t),
+ num_transitions, f) != num_transitions ||
+ fread((PTR) type_idxs, 1, num_transitions, f) != num_transitions)
+ goto lose;
+
+ for (i = 0; i < num_transitions; ++i)
+ transitions[i] = uc2ul (&transitions[i]);
+
+ for (i = 0; i < num_types; ++i)
+ {
+ unsigned char x[4];
+ if (fread((PTR) x, 1, 4, f) != 4 ||
+ fread((PTR) &types[i].isdst, 1, 1, f) != 1 ||
+ fread((PTR) &types[i].idx, 1, 1, f) != 1)
+ goto lose;
+ types[i].offset = (long int) uc2ul(x);
+ }
+
+ if (fread((PTR) zone_names, 1, chars, f) != chars)
+ goto lose;
+
+ for (i = 0; i < num_leaps; ++i)
+ {
+ unsigned char x[4];
+ if (fread((PTR) x, 1, sizeof(x), f) != sizeof(x))
+ goto lose;
+ leaps[i].transition = (time_t) uc2ul(x);
+ if (fread((PTR) x, 1, sizeof(x), f) != sizeof(x))
+ goto lose;
+ leaps[i].change = (long int) uc2ul(x);
+ }
+
+ for (i = 0; i < num_isstd; ++i)
+ {
+ char c = getc(f);
+ if (c == EOF)
+ goto lose;
+ types[i].isstd = c != 0;
+ }
+ while (i < num_types)
+ types[i++].isstd = 0;
+
+ (void) fclose(f);
+
+ compute_tzname_max (chars);
+
+ __use_tzfile = 1;
+ return;
+
+ lose:;
+ (void) fclose(f);
+}
+
+void
+DEFUN(__tzfile_default, (std, dst, stdoff, dstoff),
+ char *std AND char *dst AND
+ long int stdoff AND long int dstoff)
+{
+ size_t stdlen, dstlen, i;
+
+ __tzfile_read (TZDEFRULES);
+ if (!__use_tzfile)
+ return;
+
+ if (num_types < 2)
+ {
+ __use_tzfile = 0;
+ return;
+ }
+
+ free (zone_names);
+
+ stdlen = strlen (std) + 1;
+ dstlen = strlen (dst) + 1;
+ zone_names = malloc (stdlen + dstlen);
+ if (zone_names == NULL)
+ {
+ __use_tzfile = 0;
+ return;
+ }
+ memcpy (zone_names, std, stdlen);
+ memcpy (&zone_names[stdlen], dst, dstlen);
+
+ for (i = 0; i < num_types; ++i)
+ if (types[i].isdst)
+ {
+ types[i].idx = stdlen;
+ if (dst[0] != '\0')
+ types[i].offset = dstoff;
+ }
+ else
+ {
+ types[i].idx = 0;
+ if (dst[0] != '\0')
+ types[i].offset = stdoff;
+ }
+
+ compute_tzname_max (stdlen + dstlen);
+}
+
+int
+DEFUN(__tzfile_compute, (timer, leap_correct, leap_hit),
+ time_t timer AND long int *leap_correct AND int *leap_hit)
+{
+ struct ttinfo *info;
+ register size_t i;
+
+ if (num_transitions == 0 || timer < transitions[0])
+ {
+ /* TIMER is before any transition (or there are no transitions).
+ Choose the first non-DST type
+ (or the first if they're all DST types). */
+ i = 0;
+ while (i < num_types && types[i].isdst)
+ ++i;
+ if (i == num_types)
+ i = 0;
+ }
+ else
+ {
+ /* Find the first transition after TIMER, and
+ then pick the type of the transition before it. */
+ for (i = 1; i < num_transitions; ++i)
+ if (timer < transitions[i])
+ break;
+ i = type_idxs[i - 1];
+ }
+
+ info = &types[i];
+ __daylight = info->isdst;
+ __timezone = info->offset;
+ for (i = 0; i < num_types && i < sizeof (__tzname) / sizeof (__tzname[0]);
+ ++i)
+ __tzname[types[i].isdst] = &zone_names[types[i].idx];
+ if (info->isdst < sizeof (__tzname) / sizeof (__tzname[0]))
+ __tzname[info->isdst] = &zone_names[info->idx];
+
+ *leap_correct = 0L;
+ *leap_hit = 0;
+
+ /* Find the last leap second correction transition time before TIMER. */
+ i = num_leaps;
+ do
+ if (i-- == 0)
+ return 1;
+ while (timer < leaps[i].transition);
+
+ /* Apply its correction. */
+ *leap_correct = leaps[i].change;
+
+ if (timer == leaps[i].transition && /* Exactly at the transition time. */
+ ((i == 0 && leaps[i].change > 0) ||
+ leaps[i].change > leaps[i - 1].change))
+ {
+ *leap_hit = 1;
+ while (i > 0 &&
+ leaps[i].transition == leaps[i - 1].transition + 1 &&
+ leaps[i].change == leaps[i - 1].change + 1)
+ {
+ ++*leap_hit;
+ --i;
+ }
+ }
+
+ return 1;
+}
+
+void
+DEFUN(compute_tzname_max, (chars), size_t chars)
+{
+ extern long int __tzname_cur_max; /* Defined in __tzset.c. */
+
+ const char *p;
+
+ p = zone_names;
+ do
+ {
+ const char *start = p;
+ while (*p != '\0')
+ ++p;
+ if (p - start > __tzname_cur_max)
+ __tzname_cur_max = p - start;
+ } while (++p < &zone_names[chars]);
+}