De-K&R-ify function prototyps and remove register keyword.
[dragonfly.git] / usr.sbin / zic / zdump.c
1 #ifndef lint
2 #ifndef NOID
3 static char     elsieid[] = "@(#)zdump.c        7.28";
4 #endif /* !defined NOID */
5 #endif /* !defined lint */
6
7 /*
8  * @(#)zdump.c  7.28
9  * $FreeBSD: src/usr.sbin/zic/zdump.c,v 1.7 1999/08/28 01:21:19 peter Exp $
10  * $DragonFly: src/usr.sbin/zic/zdump.c,v 1.3 2004/02/29 16:55:28 joerg Exp $
11  */
12 /*
13 ** This code has been made independent of the rest of the time
14 ** conversion package to increase confidence in the verification it provides.
15 ** You can use this code to help in verifying other implementations.
16 */
17
18 #include <err.h>
19 #include <stdio.h>      /* for stdout, stderr */
20 #include <stdlib.h>     /* for exit, malloc, atoi */
21 #include <string.h>     /* for strcpy */
22 #include <sys/types.h>  /* for time_t */
23 #include <time.h>       /* for struct tm */
24 #include <unistd.h>
25
26 #ifndef MAX_STRING_LENGTH
27 #define MAX_STRING_LENGTH       1024
28 #endif /* !defined MAX_STRING_LENGTH */
29
30 #ifndef TRUE
31 #define TRUE            1
32 #endif /* !defined TRUE */
33
34 #ifndef FALSE
35 #define FALSE           0
36 #endif /* !defined FALSE */
37
38 #ifndef EXIT_SUCCESS
39 #define EXIT_SUCCESS    0
40 #endif /* !defined EXIT_SUCCESS */
41
42 #ifndef EXIT_FAILURE
43 #define EXIT_FAILURE    1
44 #endif /* !defined EXIT_FAILURE */
45
46 #ifndef SECSPERMIN
47 #define SECSPERMIN      60
48 #endif /* !defined SECSPERMIN */
49
50 #ifndef MINSPERHOUR
51 #define MINSPERHOUR     60
52 #endif /* !defined MINSPERHOUR */
53
54 #ifndef SECSPERHOUR
55 #define SECSPERHOUR     (SECSPERMIN * MINSPERHOUR)
56 #endif /* !defined SECSPERHOUR */
57
58 #ifndef HOURSPERDAY
59 #define HOURSPERDAY     24
60 #endif /* !defined HOURSPERDAY */
61
62 #ifndef EPOCH_YEAR
63 #define EPOCH_YEAR      1970
64 #endif /* !defined EPOCH_YEAR */
65
66 #ifndef TM_YEAR_BASE
67 #define TM_YEAR_BASE    1900
68 #endif /* !defined TM_YEAR_BASE */
69
70 #ifndef DAYSPERNYEAR
71 #define DAYSPERNYEAR    365
72 #endif /* !defined DAYSPERNYEAR */
73
74 #ifndef isleap
75 #define isleap(y) ((((y) % 4) == 0 && ((y) % 100) != 0) || ((y) % 400) == 0)
76 #endif /* !defined isleap */
77
78 #if HAVE_GETTEXT - 0
79 #include "locale.h"     /* for setlocale */
80 #include "libintl.h"
81 #endif /* HAVE_GETTEXT - 0 */
82
83 #ifndef GNUC_or_lint
84 #ifdef lint
85 #define GNUC_or_lint
86 #endif /* defined lint */
87 #ifndef lint
88 #ifdef __GNUC__
89 #define GNUC_or_lint
90 #endif /* defined __GNUC__ */
91 #endif /* !defined lint */
92 #endif /* !defined GNUC_or_lint */
93
94 #ifndef INITIALIZE
95 #ifdef GNUC_or_lint
96 #define INITIALIZE(x)   ((x) = 0)
97 #endif /* defined GNUC_or_lint */
98 #ifndef GNUC_or_lint
99 #define INITIALIZE(x)
100 #endif /* !defined GNUC_or_lint */
101 #endif /* !defined INITIALIZE */
102
103 /*
104 ** For the benefit of GNU folk...
105 ** `_(MSGID)' uses the current locale's message library string for MSGID.
106 ** The default is to use gettext if available, and use MSGID otherwise.
107 */
108
109 #ifndef _
110 #if HAVE_GETTEXT - 0
111 #define _(msgid) gettext(msgid)
112 #else /* !(HAVE_GETTEXT - 0) */
113 #define _(msgid) msgid
114 #endif /* !(HAVE_GETTEXT - 0) */
115 #endif /* !defined _ */
116
117 #ifndef TZ_DOMAIN
118 #define TZ_DOMAIN "tz"
119 #endif /* !defined TZ_DOMAIN */
120
121 extern char **  environ;
122 extern char *   tzname[2];
123
124 static char     *abbr(struct tm *tmp);
125 static long      delta(struct tm *newp, struct tm *oldp);
126 static time_t    hunt(char *name, time_t lot, time_t hit);
127 static size_t    longest;
128 static char     *progname;
129 static void      show(char *zone, time_t t, int v);
130 static void      usage(void);
131
132 int
133 main(int argc, char *argv[])
134 {
135         int i;
136         int c;
137         int vflag;
138         char *cutoff;
139         int cutyear;
140         long cuttime;
141         char **fakeenv;
142         time_t now;
143         time_t t;
144         time_t newt;
145         time_t hibit;
146         struct tm tm;
147         struct tm newtm;
148
149         INITIALIZE(cuttime);
150 #if HAVE_GETTEXT - 0
151         (void) setlocale(LC_MESSAGES, "");
152 #ifdef TZ_DOMAINDIR
153         (void) bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR);
154 #endif /* defined(TEXTDOMAINDIR) */
155         (void) textdomain(TZ_DOMAIN);
156 #endif /* HAVE_GETTEXT - 0 */
157         vflag = 0;
158         cutoff = NULL;
159         while ((c = getopt(argc, argv, "c:v")) == 'c' || c == 'v')
160                 if (c == 'v')
161                         vflag = 1;
162                 else    cutoff = optarg;
163         if ((c != EOF && c != -1) ||
164                 (optind == argc - 1 && strcmp(argv[optind], "=") == 0)) {
165                         usage();
166         }
167         if (cutoff != NULL) {
168                 int     y;
169
170                 cutyear = atoi(cutoff);
171                 cuttime = 0;
172                 for (y = EPOCH_YEAR; y < cutyear; ++y)
173                         cuttime += DAYSPERNYEAR + isleap(y);
174                 cuttime *= SECSPERHOUR * HOURSPERDAY;
175         }
176         (void) time(&now);
177         longest = 0;
178         for (i = optind; i < argc; ++i)
179                 if (strlen(argv[i]) > longest)
180                         longest = strlen(argv[i]);
181         for (hibit = 1; (hibit << 1) != 0; hibit <<= 1)
182                 continue;
183         {
184                 int from;
185                 int to;
186
187                 for (i = 0;  environ[i] != NULL;  ++i)
188                         continue;
189                 fakeenv = (char **) malloc((size_t) ((i + 2) *
190                         sizeof *fakeenv));
191                 if (fakeenv == NULL ||
192                         (fakeenv[0] = (char *) malloc((size_t) (longest +
193                                 4))) == NULL)
194                                         errx(EXIT_FAILURE,
195                                              _("malloc() failed"));
196                 to = 0;
197                 (void) strcpy(fakeenv[to++], "TZ=");
198                 for (from = 0; environ[from] != NULL; ++from)
199                         if (strncmp(environ[from], "TZ=", 3) != 0)
200                                 fakeenv[to++] = environ[from];
201                 fakeenv[to] = NULL;
202                 environ = fakeenv;
203         }
204         for (i = optind; i < argc; ++i) {
205                 static char     buf[MAX_STRING_LENGTH];
206
207                 (void) strcpy(&fakeenv[0][3], argv[i]);
208                 if (!vflag) {
209                         show(argv[i], now, FALSE);
210                         continue;
211                 }
212                 /*
213                 ** Get lowest value of t.
214                 */
215                 t = hibit;
216                 if (t > 0)              /* time_t is unsigned */
217                         t = 0;
218                 show(argv[i], t, TRUE);
219                 t += SECSPERHOUR * HOURSPERDAY;
220                 show(argv[i], t, TRUE);
221                 tm = *localtime(&t);
222                 (void) strncpy(buf, abbr(&tm), (sizeof buf) - 1);
223                 for ( ; ; ) {
224                         if (cutoff != NULL && t >= cuttime)
225                                 break;
226                         newt = t + SECSPERHOUR * 12;
227                         if (cutoff != NULL && newt >= cuttime)
228                                 break;
229                         if (newt <= t)
230                                 break;
231                         newtm = *localtime(&newt);
232                         if (delta(&newtm, &tm) != (newt - t) ||
233                                 newtm.tm_isdst != tm.tm_isdst ||
234                                 strcmp(abbr(&newtm), buf) != 0) {
235                                         newt = hunt(argv[i], t, newt);
236                                         newtm = *localtime(&newt);
237                                         (void) strncpy(buf, abbr(&newtm),
238                                                 (sizeof buf) - 1);
239                         }
240                         t = newt;
241                         tm = newtm;
242                 }
243                 /*
244                 ** Get highest value of t.
245                 */
246                 t = ~((time_t) 0);
247                 if (t < 0)              /* time_t is signed */
248                         t &= ~hibit;
249                 t -= SECSPERHOUR * HOURSPERDAY;
250                 show(argv[i], t, TRUE);
251                 t += SECSPERHOUR * HOURSPERDAY;
252                 show(argv[i], t, TRUE);
253         }
254         if (fflush(stdout) || ferror(stdout))
255                 errx(EXIT_FAILURE, _("error writing standard output"));
256         exit(EXIT_SUCCESS);
257
258         /* gcc -Wall pacifier */
259         for ( ; ; )
260                 continue;
261 }
262
263 static void
264 usage(void)
265 {
266         fprintf(stderr, _("usage: zdump [-v] [-c cutoff] zonename ...\n"));
267         exit(EXIT_FAILURE);
268 }
269
270 static time_t
271 hunt(char *name, time_t lot, time_t hit)
272 {
273         time_t          t;
274         struct tm       lotm;
275         struct tm       tm;
276         static char     loab[MAX_STRING_LENGTH];
277
278         lotm = *localtime(&lot);
279         (void) strncpy(loab, abbr(&lotm), (sizeof loab) - 1);
280         while ((hit - lot) >= 2) {
281                 t = lot / 2 + hit / 2;
282                 if (t <= lot)
283                         ++t;
284                 else if (t >= hit)
285                         --t;
286                 tm = *localtime(&t);
287                 if (delta(&tm, &lotm) == (t - lot) &&
288                         tm.tm_isdst == lotm.tm_isdst &&
289                         strcmp(abbr(&tm), loab) == 0) {
290                                 lot = t;
291                                 lotm = tm;
292                 } else  hit = t;
293         }
294         show(name, lot, TRUE);
295         show(name, hit, TRUE);
296         return hit;
297 }
298
299 /*
300 ** Thanks to Paul Eggert (eggert@twinsun.com) for logic used in delta.
301 */
302
303 static long
304 delta(struct tm *newp, struct tm *oldp)
305 {
306         long    result;
307         int     tmy;
308
309         if (newp->tm_year < oldp->tm_year)
310                 return -delta(oldp, newp);
311         result = 0;
312         for (tmy = oldp->tm_year; tmy < newp->tm_year; ++tmy)
313                 result += DAYSPERNYEAR + isleap(tmy + TM_YEAR_BASE);
314         result += newp->tm_yday - oldp->tm_yday;
315         result *= HOURSPERDAY;
316         result += newp->tm_hour - oldp->tm_hour;
317         result *= MINSPERHOUR;
318         result += newp->tm_min - oldp->tm_min;
319         result *= SECSPERMIN;
320         result += newp->tm_sec - oldp->tm_sec;
321         return result;
322 }
323
324 static void
325 show(char *zone, time_t t, int v)
326 {
327         struct tm *     tmp;
328
329         (void) printf("%-*s  ", (int) longest, zone);
330         if (v)
331                 (void) printf("%.24s UTC = ", asctime(gmtime(&t)));
332         tmp = localtime(&t);
333         (void) printf("%.24s", asctime(tmp));
334         if (*abbr(tmp) != '\0')
335                 (void) printf(" %s", abbr(tmp));
336         if (v) {
337                 (void) printf(" isdst=%d", tmp->tm_isdst);
338 #ifdef TM_GMTOFF
339                 (void) printf(" gmtoff=%ld", tmp->TM_GMTOFF);
340 #endif /* defined TM_GMTOFF */
341         }
342         (void) printf("\n");
343 }
344
345 static char *
346 abbr(struct tm *tmp)
347 {
348         char * result;
349         static char nada;
350
351         if (tmp->tm_isdst != 0 && tmp->tm_isdst != 1)
352                 return &nada;
353         result = tzname[tmp->tm_isdst];
354         return (result == NULL) ? &nada : result;
355 }