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compat_timezone.c revision 1.4 
      1 /*	$NetBSD: compat_timezone.c,v 1.4 2012/03/20 17:05:59 matt Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1987, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 #if defined(LIBC_SCCS) && !defined(lint)
     34 #if 0
     35 static char sccsid[] = "@(#)timezone.c	8.1 (Berkeley) 6/4/93";
     36 #else
     37 __RCSID("$NetBSD: compat_timezone.c,v 1.4 2012/03/20 17:05:59 matt Exp $");
     38 #endif
     39 #endif /* LIBC_SCCS and not lint */
     40 
     41 #define __LIBC12_SOURCE__
     42 
     43 #include "namespace.h"
     44 #include <sys/types.h>
     45 #include <time.h>
     46 #include <compat/include/time.h>
     47 #include <stdio.h>
     48 #include <stdlib.h>
     49 #include <string.h>
     50 #include <tzfile.h>
     51 
     52 __warn_references(timezone,
     53      "warning: reference to compatibility timezone; include <time.h> to generate correct reference")
     54 
     55 /*
     56  * timezone --
     57  *	The arguments are the number of minutes of time you are westward
     58  *	from Greenwich and whether DST is in effect.  It returns a string
     59  *	giving the name of the local timezone.  Should be replaced, in the
     60  *	application code, by a call to localtime.
     61  */
     62 
     63 char *_tztab(int, int);
     64 
     65 static char	czone[TZ_MAX_CHARS];		/* space for zone name */
     66 
     67 char *timezone(int, int);
     68 char *
     69 timezone(int zone, int dst)
     70 {
     71 	char	*beg,
     72 			*end;
     73 
     74 	if ((beg = getenv("TZNAME")) != NULL) {	/* set in environment */
     75 		if ((end = strchr(beg, ',')) != NULL) {	/* "PST,PDT" */
     76 			if (dst)
     77 				return(++end);
     78 			*end = '\0';
     79 			(void)strlcpy(czone, beg, sizeof(czone));
     80 			*end = ',';
     81 			return(czone);
     82 		}
     83 		return(beg);
     84 	}
     85 	return(_tztab(zone,dst));	/* default: table or created zone */
     86 }
     87 
     88 static const struct zone {
     89 	int		offset;
     90 	const char	*stdzone;
     91 	const char	*dlzone;
     92 } zonetab[] = {
     93 	{ -1*60,	"MET",	"MET DST" },	/* Middle European */
     94 	{ -2*60,	"EET",	"EET DST" },	/* Eastern European */
     95 	{ 4*60,		"AST",	"ADT" },	/* Atlantic */
     96 	{ 5*60,		"EST",	"EDT" },	/* Eastern */
     97 	{ 6*60,		"CST",	"CDT" },	/* Central */
     98 	{ 7*60,		"MST",	"MDT" },	/* Mountain */
     99 	{ 8*60,		"PST",	"PDT" },	/* Pacific */
    100 #ifdef notdef
    101 	/* there's no way to distinguish this from WET */
    102 	{ 0,		"GMT",	0 },		/* Greenwich */
    103 #endif
    104 	{ 0*60,		"WET",	"WET DST" },	/* Western European */
    105 	{ -10*60,	"EST",	"EST" },	/* Aust: Eastern */
    106      	{ -10*60+30,	"CST",	"CST" },	/* Aust: Central */
    107  	{ -8*60,	"WST",	0 },		/* Aust: Western */
    108 	{ -1,		NULL,	NULL }
    109 };
    110 
    111 /*
    112  * _tztab --
    113  *	check static tables or create a new zone name; broken out so that
    114  *	we can make a guess as to what the zone is if the standard tables
    115  *	aren't in place in /etc.  DO NOT USE THIS ROUTINE OUTSIDE OF THE
    116  *	STANDARD LIBRARY.
    117  */
    118 char *
    119 _tztab(int zone, int dst)
    120 {
    121 	const struct zone	*zp;
    122 	char	sign;
    123 
    124 	for (zp = zonetab; zp->offset != -1;++zp)	/* static tables */
    125 		if (zp->offset == zone) {
    126 			if (dst && zp->dlzone)
    127 				return __UNCONST(zp->dlzone);
    128 			if (!dst && zp->stdzone)
    129 				return __UNCONST(zp->stdzone);
    130 		}
    131 
    132 	if (zone < 0) {					/* create one */
    133 		zone = -zone;
    134 		sign = '+';
    135 	}
    136 	else
    137 		sign = '-';
    138 	(void)snprintf(czone, TZ_MAX_CHARS, "GMT%c%d:%02d", sign, zone / 60,
    139 	     zone % 60);
    140 	return(czone);
    141 }
    142