1 /* 2 * Copyright (c) 1987, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * %sccs.include.redist.c% 6 */ 7 8 #if defined(LIBC_SCCS) && !defined(lint) 9 static char sccsid[] = "@(#)timezone.c 8.1 (Berkeley) 06/04/93"; 10 #endif /* LIBC_SCCS and not lint */ 11 12 #include <sys/types.h> 13 #include <sys/time.h> 14 #include <stdio.h> 15 #include <stdlib.h> 16 #include <string.h> 17 #include <tzfile.h> 18 19 char *_tztab(); 20 21 /* 22 * timezone -- 23 * The arguments are the number of minutes of time you are westward 24 * from Greenwich and whether DST is in effect. It returns a string 25 * giving the name of the local timezone. Should be replaced, in the 26 * application code, by a call to localtime. 27 */ 28 29 static char czone[TZ_MAX_CHARS]; /* space for zone name */ 30 31 char * 32 timezone(zone, dst) 33 int zone, 34 dst; 35 { 36 register char *beg, 37 *end; 38 39 if (beg = getenv("TZNAME")) { /* set in environment */ 40 if (end = index(beg, ',')) { /* "PST,PDT" */ 41 if (dst) 42 return(++end); 43 *end = '\0'; 44 (void)strncpy(czone,beg,sizeof(czone) - 1); 45 czone[sizeof(czone) - 1] = '\0'; 46 *end = ','; 47 return(czone); 48 } 49 return(beg); 50 } 51 return(_tztab(zone,dst)); /* default: table or created zone */ 52 } 53 54 static struct zone { 55 int offset; 56 char *stdzone; 57 char *dlzone; 58 } zonetab[] = { 59 -1*60, "MET", "MET DST", /* Middle European */ 60 -2*60, "EET", "EET DST", /* Eastern European */ 61 4*60, "AST", "ADT", /* Atlantic */ 62 5*60, "EST", "EDT", /* Eastern */ 63 6*60, "CST", "CDT", /* Central */ 64 7*60, "MST", "MDT", /* Mountain */ 65 8*60, "PST", "PDT", /* Pacific */ 66 #ifdef notdef 67 /* there's no way to distinguish this from WET */ 68 0, "GMT", 0, /* Greenwich */ 69 #endif 70 0*60, "WET", "WET DST", /* Western European */ 71 -10*60, "EST", "EST", /* Aust: Eastern */ 72 -10*60+30, "CST", "CST", /* Aust: Central */ 73 -8*60, "WST", 0, /* Aust: Western */ 74 -1 75 }; 76 77 /* 78 * _tztab -- 79 * check static tables or create a new zone name; broken out so that 80 * we can make a guess as to what the zone is if the standard tables 81 * aren't in place in /etc. DO NOT USE THIS ROUTINE OUTSIDE OF THE 82 * STANDARD LIBRARY. 83 */ 84 char * 85 _tztab(zone,dst) 86 register int zone; 87 int dst; 88 { 89 register struct zone *zp; 90 register char sign; 91 92 for (zp = zonetab; zp->offset != -1;++zp) /* static tables */ 93 if (zp->offset == zone) { 94 if (dst && zp->dlzone) 95 return(zp->dlzone); 96 if (!dst && zp->stdzone) 97 return(zp->stdzone); 98 } 99 100 if (zone < 0) { /* create one */ 101 zone = -zone; 102 sign = '+'; 103 } 104 else 105 sign = '-'; 106 (void)sprintf(czone,"GMT%c%d:%02d",sign,zone / 60,zone % 60); 107 return(czone); 108 } 109