Thu Jan 18 00:32:43 1996 Roland McGrath <roland@churchy.gnu.ai.mit.edu>
[kopensolaris-gnu/glibc.git] / time / zdump.c
1 #ifndef lint
2 #ifndef NOID
3 static char     elsieid[] = "@(#)zdump.c        7.20";
4 #endif /* !defined NOID */
5 #endif /* !defined lint */
6
7 /*
8 ** This code has been made independent of the rest of the time
9 ** conversion package to increase confidence in the verification it provides.
10 ** You can use this code to help in verifying other implementations.
11 */
12
13 #include "stdio.h"      /* for stdout, stderr, perror */
14 #include "string.h"     /* for strcpy */
15 #include "sys/types.h"  /* for time_t */
16 #include "time.h"       /* for struct tm */
17 #include "stdlib.h"     /* for exit, malloc, atoi */
18
19 #ifndef MAX_STRING_LENGTH
20 #define MAX_STRING_LENGTH       1024
21 #endif /* !defined MAX_STRING_LENGTH */
22
23 #ifndef TRUE
24 #define TRUE            1
25 #endif /* !defined TRUE */
26
27 #ifndef FALSE
28 #define FALSE           0
29 #endif /* !defined FALSE */
30
31 #ifndef EXIT_SUCCESS
32 #define EXIT_SUCCESS    0
33 #endif /* !defined EXIT_SUCCESS */
34
35 #ifndef EXIT_FAILURE
36 #define EXIT_FAILURE    1
37 #endif /* !defined EXIT_FAILURE */
38
39 #ifndef SECSPERMIN
40 #define SECSPERMIN      60
41 #endif /* !defined SECSPERMIN */
42
43 #ifndef MINSPERHOUR
44 #define MINSPERHOUR     60
45 #endif /* !defined MINSPERHOUR */
46
47 #ifndef SECSPERHOUR
48 #define SECSPERHOUR     (SECSPERMIN * MINSPERHOUR)
49 #endif /* !defined SECSPERHOUR */
50
51 #ifndef HOURSPERDAY
52 #define HOURSPERDAY     24
53 #endif /* !defined HOURSPERDAY */
54
55 #ifndef EPOCH_YEAR
56 #define EPOCH_YEAR      1970
57 #endif /* !defined EPOCH_YEAR */
58
59 #ifndef TM_YEAR_BASE
60 #define TM_YEAR_BASE    1900
61 #endif /* !defined TM_YEAR_BASE */
62
63 #ifndef DAYSPERNYEAR
64 #define DAYSPERNYEAR    365
65 #endif /* !defined DAYSPERNYEAR */
66
67 #ifndef isleap
68 #define isleap(y) ((((y) % 4) == 0 && ((y) % 100) != 0) || ((y) % 400) == 0)
69 #endif /* !defined isleap */
70
71 #ifndef GNUC_or_lint
72 #ifdef lint
73 #define GNUC_or_lint
74 #endif /* defined lint */
75 #ifndef lint
76 #ifdef __GNUC__
77 #define GNUC_or_lint
78 #endif /* defined __GNUC__ */
79 #endif /* !defined lint */
80 #endif /* !defined GNUC_or_lint */
81
82 #ifndef INITIALIZE
83 #ifdef GNUC_or_lint
84 #define INITIALIZE(x)   ((x) = 0)
85 #endif /* defined GNUC_or_lint */
86 #ifndef GNUC_or_lint
87 #define INITIALIZE(x)
88 #endif /* !defined GNUC_or_lint */
89 #endif /* !defined INITIALIZE */
90
91 extern char **  environ;
92 extern int      getopt();
93 extern char *   optarg;
94 extern int      optind;
95 extern time_t   time();
96 extern char *   tzname[2];
97
98 static char *   abbr();
99 static long     delta();
100 static time_t   hunt();
101 static int      longest;
102 static char *   progname;
103 static void     show();
104
105 int
106 main(argc, argv)
107 int     argc;
108 char *  argv[];
109 {
110         register int            i;
111         register int            c;
112         register int            vflag;
113         register char *         cutoff;
114         register int            cutyear;
115         register long           cuttime;
116         char **                 fakeenv;
117         time_t                  now;
118         time_t                  t;
119         time_t                  newt;
120         time_t                  hibit;
121         struct tm               tm;
122         struct tm               newtm;
123
124         INITIALIZE(cuttime);
125         progname = argv[0];
126         vflag = 0;
127         cutoff = NULL;
128         while ((c = getopt(argc, argv, "c:v")) == 'c' || c == 'v')
129                 if (c == 'v')
130                         vflag = 1;
131                 else    cutoff = optarg;
132         if (c != EOF ||
133                 (optind == argc - 1 && strcmp(argv[optind], "=") == 0)) {
134                         (void) fprintf(stderr,
135 _("%s: usage is %s [ -v ] [ -c cutoff ] zonename ...\n"),
136                                 argv[0], argv[0]);
137                         (void) exit(EXIT_FAILURE);
138         }
139         if (cutoff != NULL) {
140                 int     y;
141
142                 cutyear = atoi(cutoff);
143                 cuttime = 0;
144                 for (y = EPOCH_YEAR; y < cutyear; ++y)
145                         cuttime += DAYSPERNYEAR + isleap(y);
146                 cuttime *= SECSPERHOUR * HOURSPERDAY;
147         }
148         (void) time(&now);
149         longest = 0;
150         for (i = optind; i < argc; ++i)
151                 if (strlen(argv[i]) > longest)
152                         longest = strlen(argv[i]);
153         for (hibit = 1; (hibit << 1) != 0; hibit <<= 1)
154                 continue;
155         {
156                 register int    from;
157                 register int    to;
158
159                 for (i = 0;  environ[i] != NULL;  ++i)
160                         continue;
161                 fakeenv = (char **) malloc((size_t) ((i + 2) *
162                         sizeof *fakeenv));
163                 if (fakeenv == NULL ||
164                         (fakeenv[0] = (char *) malloc((size_t) (longest +
165                                 4))) == NULL) {
166                                         (void) perror(progname);
167                                         (void) exit(EXIT_FAILURE);
168                 }
169                 to = 0;
170                 (void) strcpy(fakeenv[to++], "TZ=");
171                 for (from = 0; environ[from] != NULL; ++from)
172                         if (strncmp(environ[from], "TZ=", 3) != 0)
173                                 fakeenv[to++] = environ[from];
174                 fakeenv[to] = NULL;
175                 environ = fakeenv;
176         }
177         for (i = optind; i < argc; ++i) {
178                 static char     buf[MAX_STRING_LENGTH];
179
180                 (void) strcpy(&fakeenv[0][3], argv[i]);
181                 show(argv[i], now, FALSE);
182                 if (!vflag)
183                         continue;
184                 /*
185                 ** Get lowest value of t.
186                 */
187                 t = hibit;
188                 if (t > 0)              /* time_t is unsigned */
189                         t = 0;
190                 show(argv[i], t, TRUE);
191                 t += SECSPERHOUR * HOURSPERDAY;
192                 show(argv[i], t, TRUE);
193                 tm = *localtime(&t);
194                 (void) strncpy(buf, abbr(&tm), (sizeof buf) - 1);
195                 for ( ; ; ) {
196                         if (cutoff != NULL && t >= cuttime)
197                                 break;
198                         newt = t + SECSPERHOUR * 12;
199                         if (cutoff != NULL && newt >= cuttime)
200                                 break;
201                         if (newt <= t)
202                                 break;
203                         newtm = *localtime(&newt);
204                         if (delta(&newtm, &tm) != (newt - t) ||
205                                 newtm.tm_isdst != tm.tm_isdst ||
206                                 strcmp(abbr(&newtm), buf) != 0) {
207                                         newt = hunt(argv[i], t, newt);
208                                         newtm = *localtime(&newt);
209                                         (void) strncpy(buf, abbr(&newtm),
210                                                 (sizeof buf) - 1);
211                         }
212                         t = newt;
213                         tm = newtm;
214                 }
215                 /*
216                 ** Get highest value of t.
217                 */
218                 t = ~((time_t) 0);
219                 if (t < 0)              /* time_t is signed */
220                         t &= ~hibit;
221                 t -= SECSPERHOUR * HOURSPERDAY;
222                 show(argv[i], t, TRUE);
223                 t += SECSPERHOUR * HOURSPERDAY;
224                 show(argv[i], t, TRUE);
225         }
226         if (fflush(stdout) || ferror(stdout)) {
227                 (void) fprintf(stderr, _("%s: Error writing standard output "),
228                         argv[0]);
229                 (void) perror(_("standard output"));
230                 (void) exit(EXIT_FAILURE);
231         }
232         exit(EXIT_SUCCESS);
233
234         /* gcc -Wall pacifier */
235         for ( ; ; )
236                 continue;
237 }
238
239 static time_t
240 hunt(name, lot, hit)
241 char *  name;
242 time_t  lot;
243 time_t  hit;
244 {
245         time_t          t;
246         struct tm       lotm;
247         struct tm       tm;
248         static char     loab[MAX_STRING_LENGTH];
249
250         lotm = *localtime(&lot);
251         (void) strncpy(loab, abbr(&lotm), (sizeof loab) - 1);
252         while ((hit - lot) >= 2) {
253                 t = lot / 2 + hit / 2;
254                 if (t <= lot)
255                         ++t;
256                 else if (t >= hit)
257                         --t;
258                 tm = *localtime(&t);
259                 if (delta(&tm, &lotm) == (t - lot) &&
260                         tm.tm_isdst == lotm.tm_isdst &&
261                         strcmp(abbr(&tm), loab) == 0) {
262                                 lot = t;
263                                 lotm = tm;
264                 } else  hit = t;
265         }
266         show(name, lot, TRUE);
267         show(name, hit, TRUE);
268         return hit;
269 }
270
271 /*
272 ** Thanks to Paul Eggert (eggert@twinsun.com) for logic used in delta.
273 */
274
275 static long
276 delta(newp, oldp)
277 struct tm *     newp;
278 struct tm *     oldp;
279 {
280         long    result;
281         int     tmy;
282
283         if (newp->tm_year < oldp->tm_year)
284                 return -delta(oldp, newp);
285         result = 0;
286         for (tmy = oldp->tm_year; tmy < newp->tm_year; ++tmy)
287                 result += DAYSPERNYEAR + isleap(tmy + TM_YEAR_BASE);
288         result += newp->tm_yday - oldp->tm_yday;
289         result *= HOURSPERDAY;
290         result += newp->tm_hour - oldp->tm_hour;
291         result *= MINSPERHOUR;
292         result += newp->tm_min - oldp->tm_min;
293         result *= SECSPERMIN;
294         result += newp->tm_sec - oldp->tm_sec;
295         return result;
296 }
297
298 extern struct tm *      localtime();
299
300 static void
301 show(zone, t, v)
302 char *  zone;
303 time_t  t;
304 int     v;
305 {
306         struct tm *     tmp;
307
308         (void) printf("%-*s  ", longest, zone);
309         if (v)
310                 (void) printf("%.24s GMT = ", asctime(gmtime(&t)));
311         tmp = localtime(&t);
312         (void) printf("%.24s", asctime(tmp));
313         if (*abbr(tmp) != '\0')
314                 (void) printf(" %s", abbr(tmp));
315         if (v) {
316                 (void) printf(" isdst=%d", tmp->tm_isdst);
317 #ifdef TM_GMTOFF
318                 (void) printf(" gmtoff=%ld", tmp->TM_GMTOFF);
319 #endif /* defined TM_GMTOFF */
320         }
321         (void) printf("\n");
322 }
323
324 static char *
325 abbr(tmp)
326 struct tm *     tmp;
327 {
328         register char * result;
329         static char     nada;
330
331         if (tmp->tm_isdst != 0 && tmp->tm_isdst != 1)
332                 return &nada;
333         result = tzname[tmp->tm_isdst];
334         return (result == NULL) ? &nada : result;
335 }