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481 lines
12 KiB
C
481 lines
12 KiB
C
/* Copyright (C) 1991, 92, 93, 94, 95, 96 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 <ctype.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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#define NOID
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#include "tzfile.h"
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extern int __use_tzfile;
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extern void EXFUN(__tzfile_read, (CONST char *file));
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extern void EXFUN(__tzfile_default, (char *std AND char *dst AND
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long int stdoff AND long int dstoff));
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extern int EXFUN(__tzfile_compute, (time_t, struct tm));
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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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#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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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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int __tzset_run = 0;
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/* Interpret the TZ envariable. */
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void
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DEFUN_VOID(__tzset)
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{
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register CONST char *tz;
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register size_t l;
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unsigned short int hh, mm, ss;
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unsigned short int whichrule;
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/* Free old storage. */
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if (tz_rules[0].name != NULL && *tz_rules[0].name != '\0')
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free((PTR) tz_rules[0].name);
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if (tz_rules[1].name != NULL && *tz_rules[1].name != '\0' &&
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tz_rules[1].name != tz_rules[0].name)
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free((PTR) tz_rules[1].name);
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tz = getenv("TZ");
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if (tz != NULL && *tz == ':')
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{
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__tzfile_read(tz + 1);
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if (__use_tzfile)
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{
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__tzset_run = 1;
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return;
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}
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else
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tz = NULL;
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}
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if (tz == NULL || *tz == '\0')
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{
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__tzfile_read((char *) NULL);
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if (!__use_tzfile)
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{
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const char UTC[] = "UTC";
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size_t len = sizeof UTC;
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tz_rules[0].name = (char *) malloc(len);
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if (tz_rules[0].name == NULL)
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return;
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tz_rules[1].name = (char *) malloc(len);
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if (tz_rules[1].name == NULL)
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return;
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memcpy ((PTR) tz_rules[0].name, UTC, len);
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memcpy ((PTR) tz_rules[1].name, UTC, len);
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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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}
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__tzset_run = 1;
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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 = (char *) "";
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/* Get the standard timezone name. */
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tz_rules[0].name = (char *) malloc (strlen (tz) + 1);
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if (tz_rules[0].name == NULL)
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/* Don't set __tzset_run so we will try again. */
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return;
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if (sscanf(tz, "%[^0-9,+-]", tz_rules[0].name) != 1 ||
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(l = strlen(tz_rules[0].name)) < 3)
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{
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free (tz_rules[0].name);
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tz_rules[0].name = (char *) "";
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return;
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}
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{
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char *n = realloc ((PTR) tz_rules[0].name, l + 1);
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if (n != NULL)
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tz_rules[0].name = n;
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}
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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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return;
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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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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 = malloc (strlen(tz) + 1);
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if (n != NULL)
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{
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tz_rules[1].name = n;
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if (sscanf(tz, "%[^0-9,+-]", tz_rules[1].name) != 1 ||
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(l = strlen(tz_rules[1].name)) < 3)
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{
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free (n);
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tz_rules[1].name = (char *) "";
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goto done_names; /* Punt on name, set up the offsets. */
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}
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n = realloc ((PTR) tz_rules[1].name, l + 1);
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if (n != NULL)
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tz_rules[1].name = n;
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}
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}
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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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done_names:
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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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__tzset_run = 1;
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return;
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}
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}
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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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if (*tz == ',')
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{
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++tz;
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if (*tz == '\0')
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return;
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}
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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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__tzset_run = 1;
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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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long int __tzname_cur_max;
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long int
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DEFUN_VOID(__tzname_max)
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{
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if (! __tzset_run)
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__tzset ();
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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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DEFUN(compute_change, (rule, year), tz_rule *rule AND 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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register int i, d, m1, yy0, yy1, yy2, dow;
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register 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 >= 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. */
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t += d * SECSPERDAY;
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}
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break;
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}
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/* T is now the Epoch-relative time of 0:00:00 GMT on the day we want.
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Just add the time of day and local offset from GMT, and we're done. */
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rule->change = t + rule->offset + rule->secs;
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rule->computed_for = year;
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return 1;
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}
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/* Figure out the correct timezone for *TIMER and TM (which must be the same)
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and set `__tzname', `__timezone', and `__daylight' accordingly.
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Return nonzero on success, zero on failure. */
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int
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DEFUN(__tz_compute, (timer, tm),
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time_t timer AND const struct tm *tm)
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{
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if (! __tzset_run)
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__tzset ();
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if (! compute_change (&tz_rules[0], 1900 + tm->tm_year) ||
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! compute_change (&tz_rules[1], 1900 + tm->tm_year))
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return 0;
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__daylight = timer >= tz_rules[0].change && timer < tz_rules[1].change;
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__timezone = tz_rules[__daylight ? 1 : 0].offset;
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__tzname[0] = (char *) tz_rules[0].name;
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__tzname[1] = (char *) tz_rules[1].name;
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{
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/* Keep __tzname_cur_max up to date. */
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size_t len0 = strlen (__tzname[0]);
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size_t len1 = strlen (__tzname[1]);
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if (len0 > __tzname_cur_max)
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__tzname_cur_max = len0;
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if (len1 > __tzname_cur_max)
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__tzname_cur_max = len1;
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}
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return 1;
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}
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weak_alias (__tzset, tzset)
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