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zdump.c revision 1.2.2.2 
      1 /*	$NetBSD: zdump.c,v 1.2.2.2 1995/03/10 18:12:44 jtc Exp $	*/
      2 
      3 #ifndef lint
      4 #ifndef NOID
      5 static char	elsieid[] = "@(#)zdump.c	7.20";
      6 #endif /* !defined NOID */
      7 #endif /* !defined lint */
      8 
      9 /*
     10 ** This code has been made independent of the rest of the time
     11 ** conversion package to increase confidence in the verification it provides.
     12 ** You can use this code to help in verifying other implementations.
     13 */
     14 
     15 #include "stdio.h"	/* for stdout, stderr, perror */
     16 #include "string.h"	/* for strcpy */
     17 #include "sys/types.h"	/* for time_t */
     18 #include "time.h"	/* for struct tm */
     19 #include "stdlib.h"	/* for exit, malloc, atoi */
     20 
     21 #ifndef MAX_STRING_LENGTH
     22 #define MAX_STRING_LENGTH	1024
     23 #endif /* !defined MAX_STRING_LENGTH */
     24 
     25 #ifndef TRUE
     26 #define TRUE		1
     27 #endif /* !defined TRUE */
     28 
     29 #ifndef FALSE
     30 #define FALSE		0
     31 #endif /* !defined FALSE */
     32 
     33 #ifndef EXIT_SUCCESS
     34 #define EXIT_SUCCESS	0
     35 #endif /* !defined EXIT_SUCCESS */
     36 
     37 #ifndef EXIT_FAILURE
     38 #define EXIT_FAILURE	1
     39 #endif /* !defined EXIT_FAILURE */
     40 
     41 #ifndef SECSPERMIN
     42 #define SECSPERMIN	60
     43 #endif /* !defined SECSPERMIN */
     44 
     45 #ifndef MINSPERHOUR
     46 #define MINSPERHOUR	60
     47 #endif /* !defined MINSPERHOUR */
     48 
     49 #ifndef SECSPERHOUR
     50 #define SECSPERHOUR	(SECSPERMIN * MINSPERHOUR)
     51 #endif /* !defined SECSPERHOUR */
     52 
     53 #ifndef HOURSPERDAY
     54 #define HOURSPERDAY	24
     55 #endif /* !defined HOURSPERDAY */
     56 
     57 #ifndef EPOCH_YEAR
     58 #define EPOCH_YEAR	1970
     59 #endif /* !defined EPOCH_YEAR */
     60 
     61 #ifndef TM_YEAR_BASE
     62 #define TM_YEAR_BASE	1900
     63 #endif /* !defined TM_YEAR_BASE */
     64 
     65 #ifndef DAYSPERNYEAR
     66 #define DAYSPERNYEAR	365
     67 #endif /* !defined DAYSPERNYEAR */
     68 
     69 #ifndef isleap
     70 #define isleap(y) ((((y) % 4) == 0 && ((y) % 100) != 0) || ((y) % 400) == 0)
     71 #endif /* !defined isleap */
     72 
     73 #ifndef GNUC_or_lint
     74 #ifdef lint
     75 #define GNUC_or_lint
     76 #endif /* defined lint */
     77 #ifndef lint
     78 #ifdef __GNUC__
     79 #define GNUC_or_lint
     80 #endif /* defined __GNUC__ */
     81 #endif /* !defined lint */
     82 #endif /* !defined GNUC_or_lint */
     83 
     84 #ifndef INITIALIZE
     85 #ifdef GNUC_or_lint
     86 #define INITIALIZE(x)	((x) = 0)
     87 #endif /* defined GNUC_or_lint */
     88 #ifndef GNUC_or_lint
     89 #define INITIALIZE(x)
     90 #endif /* !defined GNUC_or_lint */
     91 #endif /* !defined INITIALIZE */
     92 
     93 extern char **	environ;
     94 extern int	getopt();
     95 extern char *	optarg;
     96 extern int	optind;
     97 extern time_t	time();
     98 extern char *	tzname[2];
     99 
    100 static char *	abbr();
    101 static long	delta();
    102 static time_t	hunt();
    103 static int	longest;
    104 static char *	progname;
    105 static void	show();
    106 
    107 int
    108 main(argc, argv)
    109 int	argc;
    110 char *	argv[];
    111 {
    112 	register int		i;
    113 	register int		c;
    114 	register int		vflag;
    115 	register char *		cutoff;
    116 	register int		cutyear;
    117 	register long		cuttime;
    118 	char **			fakeenv;
    119 	time_t			now;
    120 	time_t			t;
    121 	time_t			newt;
    122 	time_t			hibit;
    123 	struct tm		tm;
    124 	struct tm		newtm;
    125 
    126 	INITIALIZE(cuttime);
    127 	progname = argv[0];
    128 	vflag = 0;
    129 	cutoff = NULL;
    130 	while ((c = getopt(argc, argv, "c:v")) == 'c' || c == 'v')
    131 		if (c == 'v')
    132 			vflag = 1;
    133 		else	cutoff = optarg;
    134 	if (c != EOF ||
    135 		(optind == argc - 1 && strcmp(argv[optind], "=") == 0)) {
    136 			(void) fprintf(stderr,
    137 "%s: usage is %s [ -v ] [ -c cutoff ] zonename ...\n",
    138 				argv[0], argv[0]);
    139 			(void) exit(EXIT_FAILURE);
    140 	}
    141 	if (cutoff != NULL) {
    142 		int	y;
    143 
    144 		cutyear = atoi(cutoff);
    145 		cuttime = 0;
    146 		for (y = EPOCH_YEAR; y < cutyear; ++y)
    147 			cuttime += DAYSPERNYEAR + isleap(y);
    148 		cuttime *= SECSPERHOUR * HOURSPERDAY;
    149 	}
    150 	(void) time(&now);
    151 	longest = 0;
    152 	for (i = optind; i < argc; ++i)
    153 		if (strlen(argv[i]) > longest)
    154 			longest = strlen(argv[i]);
    155 	for (hibit = 1; (hibit << 1) != 0; hibit <<= 1)
    156 		continue;
    157 	{
    158 		register int	from;
    159 		register int	to;
    160 
    161 		for (i = 0;  environ[i] != NULL;  ++i)
    162 			continue;
    163 		fakeenv = (char **) malloc((size_t) ((i + 2) *
    164 			sizeof *fakeenv));
    165 		if (fakeenv == NULL ||
    166 			(fakeenv[0] = (char *) malloc((size_t) (longest +
    167 				4))) == NULL) {
    168 					(void) perror(progname);
    169 					(void) exit(EXIT_FAILURE);
    170 		}
    171 		to = 0;
    172 		(void) strcpy(fakeenv[to++], "TZ=");
    173 		for (from = 0; environ[from] != NULL; ++from)
    174 			if (strncmp(environ[from], "TZ=", 3) != 0)
    175 				fakeenv[to++] = environ[from];
    176 		fakeenv[to] = NULL;
    177 		environ = fakeenv;
    178 	}
    179 	for (i = optind; i < argc; ++i) {
    180 		static char	buf[MAX_STRING_LENGTH];
    181 
    182 		(void) strcpy(&fakeenv[0][3], argv[i]);
    183 		show(argv[i], now, FALSE);
    184 		if (!vflag)
    185 			continue;
    186 		/*
    187 		** Get lowest value of t.
    188 		*/
    189 		t = hibit;
    190 		if (t > 0)		/* time_t is unsigned */
    191 			t = 0;
    192 		show(argv[i], t, TRUE);
    193 		t += SECSPERHOUR * HOURSPERDAY;
    194 		show(argv[i], t, TRUE);
    195 		tm = *localtime(&t);
    196 		(void) strncpy(buf, abbr(&tm), (sizeof buf) - 1);
    197 		for ( ; ; ) {
    198 			if (cutoff != NULL && t >= cuttime)
    199 				break;
    200 			newt = t + SECSPERHOUR * 12;
    201 			if (cutoff != NULL && newt >= cuttime)
    202 				break;
    203 			if (newt <= t)
    204 				break;
    205 			newtm = *localtime(&newt);
    206 			if (delta(&newtm, &tm) != (newt - t) ||
    207 				newtm.tm_isdst != tm.tm_isdst ||
    208 				strcmp(abbr(&newtm), buf) != 0) {
    209 					newt = hunt(argv[i], t, newt);
    210 					newtm = *localtime(&newt);
    211 					(void) strncpy(buf, abbr(&newtm),
    212 						(sizeof buf) - 1);
    213 			}
    214 			t = newt;
    215 			tm = newtm;
    216 		}
    217 		/*
    218 		** Get highest value of t.
    219 		*/
    220 		t = ~((time_t) 0);
    221 		if (t < 0)		/* time_t is signed */
    222 			t &= ~hibit;
    223 		t -= SECSPERHOUR * HOURSPERDAY;
    224 		show(argv[i], t, TRUE);
    225 		t += SECSPERHOUR * HOURSPERDAY;
    226 		show(argv[i], t, TRUE);
    227 	}
    228 	if (fflush(stdout) || ferror(stdout)) {
    229 		(void) fprintf(stderr, "%s: Error writing standard output ",
    230 			argv[0]);
    231 		(void) perror("standard output");
    232 		(void) exit(EXIT_FAILURE);
    233 	}
    234 	exit(EXIT_SUCCESS);
    235 
    236 	/* gcc -Wall pacifier */
    237 	for ( ; ; )
    238 		continue;
    239 }
    240 
    241 static time_t
    242 hunt(name, lot, hit)
    243 char *	name;
    244 time_t	lot;
    245 time_t	hit;
    246 {
    247 	time_t		t;
    248 	struct tm	lotm;
    249 	struct tm	tm;
    250 	static char	loab[MAX_STRING_LENGTH];
    251 
    252 	lotm = *localtime(&lot);
    253 	(void) strncpy(loab, abbr(&lotm), (sizeof loab) - 1);
    254 	while ((hit - lot) >= 2) {
    255 		t = lot / 2 + hit / 2;
    256 		if (t <= lot)
    257 			++t;
    258 		else if (t >= hit)
    259 			--t;
    260 		tm = *localtime(&t);
    261 		if (delta(&tm, &lotm) == (t - lot) &&
    262 			tm.tm_isdst == lotm.tm_isdst &&
    263 			strcmp(abbr(&tm), loab) == 0) {
    264 				lot = t;
    265 				lotm = tm;
    266 		} else	hit = t;
    267 	}
    268 	show(name, lot, TRUE);
    269 	show(name, hit, TRUE);
    270 	return hit;
    271 }
    272 
    273 /*
    274 ** Thanks to Paul Eggert (eggert (at) twinsun.com) for logic used in delta.
    275 */
    276 
    277 static long
    278 delta(newp, oldp)
    279 struct tm *	newp;
    280 struct tm *	oldp;
    281 {
    282 	long	result;
    283 	int	tmy;
    284 
    285 	if (newp->tm_year < oldp->tm_year)
    286 		return -delta(oldp, newp);
    287 	result = 0;
    288 	for (tmy = oldp->tm_year; tmy < newp->tm_year; ++tmy)
    289 		result += DAYSPERNYEAR + isleap(tmy + TM_YEAR_BASE);
    290 	result += newp->tm_yday - oldp->tm_yday;
    291 	result *= HOURSPERDAY;
    292 	result += newp->tm_hour - oldp->tm_hour;
    293 	result *= MINSPERHOUR;
    294 	result += newp->tm_min - oldp->tm_min;
    295 	result *= SECSPERMIN;
    296 	result += newp->tm_sec - oldp->tm_sec;
    297 	return result;
    298 }
    299 
    300 extern struct tm *	localtime();
    301 
    302 static void
    303 show(zone, t, v)
    304 char *	zone;
    305 time_t	t;
    306 int	v;
    307 {
    308 	struct tm *	tmp;
    309 
    310 	(void) printf("%-*s  ", longest, zone);
    311 	if (v)
    312 		(void) printf("%.24s GMT = ", asctime(gmtime(&t)));
    313 	tmp = localtime(&t);
    314 	(void) printf("%.24s", asctime(tmp));
    315 	if (*abbr(tmp) != '\0')
    316 		(void) printf(" %s", abbr(tmp));
    317 	if (v) {
    318 		(void) printf(" isdst=%d", tmp->tm_isdst);
    319 #ifdef TM_GMTOFF
    320 		(void) printf(" gmtoff=%ld", tmp->TM_GMTOFF);
    321 #endif /* defined TM_GMTOFF */
    322 	}
    323 	(void) printf("\n");
    324 }
    325 
    326 static char *
    327 abbr(tmp)
    328 struct tm *	tmp;
    329 {
    330 	register char *	result;
    331 	static char	nada;
    332 
    333 	if (tmp->tm_isdst != 0 && tmp->tm_isdst != 1)
    334 		return &nada;
    335 	result = tzname[tmp->tm_isdst];
    336 	return (result == NULL) ? &nada : result;
    337 }
    338