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/* $OpenBSD: timezone.c,v 1.10 2005/08/08 08:05:34 espie Exp $ */
/*
* Copyright (c) 1987, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/types.h>
#include <sys/time.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <tzfile.h>
char *_tztab(int, int);
/*
* timezone --
* The arguments are the number of minutes of time you are westward
* from Greenwich and whether DST is in effect. It returns a string
* giving the name of the local timezone. Should be replaced, in the
* application code, by a call to localtime.
*/
static char czone[TZ_MAX_CHARS]; /* space for zone name */
char *
timezone(int zone, int dst)
{
char *beg, *end;
if ((beg = getenv("TZNAME"))) { /* set in environment */
if ((end = strchr(beg, ','))) { /* "PST,PDT" */
if (dst)
return(++end);
*end = '\0';
strlcpy(czone,beg,sizeof(czone));
*end = ',';
return(czone);
}
return(beg);
}
return(_tztab(zone,dst)); /* default: table or created zone */
}
static struct zone {
int offset;
char *stdzone;
char *dlzone;
} zonetab[] = {
{ -1*60, "MET", "MET DST"} , /* Middle European */
{ -2*60, "EET", "EET DST"} , /* Eastern European */
{ 4*60, "AST", "ADT"} , /* Atlantic */
{ 5*60, "EST", "EDT"} , /* Eastern */
{ 6*60, "CST", "CDT"} , /* Central */
{ 7*60, "MST", "MDT"} , /* Mountain */
{ 8*60, "PST", "PDT"} , /* Pacific */
#ifdef notdef
/* there's no way to distinguish this from WET */
{ 0, "GMT", 0 }, /* Greenwich */
#endif
{ 0*60, "WET", "WET DST" }, /* Western European */
{ -10*60, "EST", "EST" }, /* Aust: Eastern */
{ -10*60+30,"CST", "CST" }, /* Aust: Central */
{ -8*60, "WST", 0 }, /* Aust: Western */
{ -1 }
};
/*
* _tztab --
* check static tables or create a new zone name; broken out so that
* we can make a guess as to what the zone is if the standard tables
* aren't in place in /etc. DO NOT USE THIS ROUTINE OUTSIDE OF THE
* STANDARD LIBRARY.
*/
char *
_tztab(int zone, int dst)
{
struct zone *zp;
char sign;
for (zp = zonetab; zp->offset != -1;++zp) /* static tables */
if (zp->offset == zone) {
if (dst && zp->dlzone)
return(zp->dlzone);
if (!dst && zp->stdzone)
return(zp->stdzone);
}
if (zone < 0) { /* create one */
zone = -zone;
sign = '+';
}
else
sign = '-';
(void)snprintf(czone, sizeof czone, "GMT%c%d:%02d",
sign,zone / 60,zone % 60);
return(czone);
}
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