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Annotation of 43BSDReno/lib/libc/gen/timezone.c, revision 1.1.1.1

1.1       root        1: /*
                      2:  * Copyright (c) 1987 Regents of the University of California.
                      3:  * All rights reserved.
                      4:  *
                      5:  * Redistribution and use in source and binary forms are permitted
                      6:  * provided that: (1) source distributions retain this entire copyright
                      7:  * notice and comment, and (2) distributions including binaries display
                      8:  * the following acknowledgement:  ``This product includes software
                      9:  * developed by the University of California, Berkeley and its contributors''
                     10:  * in the documentation or other materials provided with the distribution
                     11:  * and in all advertising materials mentioning features or use of this
                     12:  * software. Neither the name of the University nor the names of its
                     13:  * contributors may be used to endorse or promote products derived
                     14:  * from this software without specific prior written permission.
                     15:  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
                     16:  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
                     17:  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
                     18:  */
                     19: 
                     20: #if defined(LIBC_SCCS) && !defined(lint)
                     21: static char sccsid[] = "@(#)timezone.c 5.9 (Berkeley) 6/1/90";
                     22: #endif /* LIBC_SCCS and not lint */
                     23: 
                     24: #include <sys/types.h>
                     25: #include <sys/time.h>
                     26: #include <stdio.h>
                     27: #include <tzfile.h>
                     28: 
                     29: /*
                     30:  * timezone --
                     31:  *     The arguments are the number of minutes of time you are westward
                     32:  *     from Greenwich and whether DST is in effect.  It returns a string
                     33:  *     giving the name of the local timezone.  Should be replaced, in the
                     34:  *     application code, by a call to localtime.
                     35:  */
                     36: 
                     37: static char    czone[TZ_MAX_CHARS];            /* space for zone name */
                     38: 
                     39: char *
                     40: timezone(zone, dst)
                     41:        int     zone,
                     42:                dst;
                     43: {
                     44:        register char   *beg,
                     45:                        *end;
                     46:        char    *getenv(), *index(), *strncpy(), *_tztab();
                     47: 
                     48:        if (beg = getenv("TZNAME")) {           /* set in environment */
                     49:                if (end = index(beg, ',')) {    /* "PST,PDT" */
                     50:                        if (dst)
                     51:                                return(++end);
                     52:                        *end = '\0';
                     53:                        (void)strncpy(czone,beg,sizeof(czone) - 1);
                     54:                        czone[sizeof(czone) - 1] = '\0';
                     55:                        *end = ',';
                     56:                        return(czone);
                     57:                }
                     58:                return(beg);
                     59:        }
                     60:        return(_tztab(zone,dst));       /* default: table or created zone */
                     61: }
                     62: 
                     63: static struct zone {
                     64:        int     offset;
                     65:        char    *stdzone;
                     66:        char    *dlzone;
                     67: } zonetab[] = {
                     68:        -1*60,  "MET",  "MET DST",      /* Middle European */
                     69:        -2*60,  "EET",  "EET DST",      /* Eastern European */
                     70:        4*60,   "AST",  "ADT",          /* Atlantic */
                     71:        5*60,   "EST",  "EDT",          /* Eastern */
                     72:        6*60,   "CST",  "CDT",          /* Central */
                     73:        7*60,   "MST",  "MDT",          /* Mountain */
                     74:        8*60,   "PST",  "PDT",          /* Pacific */
                     75: #ifdef notdef
                     76:        /* there's no way to distinguish this from WET */
                     77:        0,      "GMT",  0,              /* Greenwich */
                     78: #endif
                     79:        0*60,   "WET",  "WET DST",      /* Western European */
                     80:        -10*60, "EST",  "EST",          /* Aust: Eastern */
                     81:      -10*60+30,        "CST",  "CST",          /* Aust: Central */
                     82:        -8*60,  "WST",  0,              /* Aust: Western */
                     83:        -1
                     84: };
                     85: 
                     86: /*
                     87:  * _tztab --
                     88:  *     check static tables or create a new zone name; broken out so that
                     89:  *     we can make a guess as to what the zone is if the standard tables
                     90:  *     aren't in place in /etc.  DO NOT USE THIS ROUTINE OUTSIDE OF THE
                     91:  *     STANDARD LIBRARY.
                     92:  */
                     93: char *
                     94: _tztab(zone,dst)
                     95:        register int    zone;
                     96:        int     dst;
                     97: {
                     98:        register struct zone    *zp;
                     99:        register char   sign;
                    100: 
                    101:        for (zp = zonetab; zp->offset != -1;++zp)       /* static tables */
                    102:                if (zp->offset == zone) {
                    103:                        if (dst && zp->dlzone)
                    104:                                return(zp->dlzone);
                    105:                        if (!dst && zp->stdzone)
                    106:                                return(zp->stdzone);
                    107:                }
                    108: 
                    109:        if (zone < 0) {                                 /* create one */
                    110:                zone = -zone;
                    111:                sign = '+';
                    112:        }
                    113:        else
                    114:                sign = '-';
                    115:        (void)sprintf(czone,"GMT%c%d:%02d",sign,zone / 60,zone % 60);
                    116:        return(czone);
                    117: }

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