timezone/zdump.c

   1 /*
   2 ** This file is in the public domain, so clarified as of
   3 ** 2009-05-17 by Arthur David Olson.
   4 */
   5
   6 #include "version.h"
   7
   8 /*
   9 ** This code has been made independent of the rest of the time
  10 ** conversion package to increase confidence in the verification it provides.
  11 ** You can use this code to help in verifying other implementations.
  12 **
  13 ** However, include private.h when debugging, so that it overrides
  14 ** time_t consistently with the rest of the package.
  15 */
  16
  17 #ifdef time_tz
  18 # include "private.h"
  19 #endif
  20
  21 #include "stdio.h"      /* for stdout, stderr, perror */
  22 #include "string.h"     /* for strcpy */
  23 #include "sys/types.h"  /* for time_t */
  24 #include "time.h"       /* for struct tm */
  25 #include "stdlib.h"     /* for exit, malloc, atoi */
  26 #include "limits.h"     /* for CHAR_BIT, LLONG_MAX */
  27 #include "ctype.h"      /* for isalpha et al. */
  28 #ifndef isascii
  29 #define isascii(x) 1
  30 #endif /* !defined isascii */
  31
  32 /*
  33 ** Substitutes for pre-C99 compilers.
  34 ** Much of this section of code is stolen from private.h.
  35 */
  36
  37 #ifndef HAVE_STDINT_H
  38 # define HAVE_STDINT_H \
  39     (199901 <= __STDC_VERSION__ || 2 < (__GLIBC__ + (0 < __GLIBC_MINOR__)))
  40 #endif
  41 #if HAVE_STDINT_H
  42 # include "stdint.h"
  43 #endif
  44 #ifndef HAVE_INTTYPES_H
  45 # define HAVE_INTTYPES_H HAVE_STDINT_H
  46 #endif
  47 #if HAVE_INTTYPES_H
  48 # include <inttypes.h>
  49 #endif
  50
  51 #ifndef INT_FAST32_MAX
  52 # if INT_MAX >> 31 == 0
  53 typedef long int_fast32_t;
  54 # else
  55 typedef int int_fast32_t;
  56 # endif
  57 #endif
  58
  59 #ifndef INTMAX_MAX
  60 # if defined LLONG_MAX || defined __LONG_LONG_MAX__
  61 typedef long long intmax_t;
  62 #  define strtoimax strtoll
  63 #  define PRIdMAX "lld"
  64 #  ifdef LLONG_MAX
  65 #   define INTMAX_MAX LLONG_MAX
  66 #  else
  67 #   define INTMAX_MAX __LONG_LONG_MAX__
  68 #  endif
  69 # else
  70 typedef long intmax_t;
  71 #  define strtoimax strtol
  72 #  define PRIdMAX "ld"
  73 #  define INTMAX_MAX LONG_MAX
  74 # endif
  75 #endif
  76
  77
  78 #ifndef ZDUMP_LO_YEAR
  79 #define ZDUMP_LO_YEAR   (-500)
  80 #endif /* !defined ZDUMP_LO_YEAR */
  81
  82 #ifndef ZDUMP_HI_YEAR
  83 #define ZDUMP_HI_YEAR   2500
  84 #endif /* !defined ZDUMP_HI_YEAR */
  85
  86 #ifndef MAX_STRING_LENGTH
  87 #define MAX_STRING_LENGTH       1024
  88 #endif /* !defined MAX_STRING_LENGTH */
  89
  90 #ifndef TRUE
  91 #define TRUE            1
  92 #endif /* !defined TRUE */
  93
  94 #ifndef FALSE
  95 #define FALSE           0
  96 #endif /* !defined FALSE */
  97
  98 #ifndef EXIT_SUCCESS
  99 #define EXIT_SUCCESS    0
 100 #endif /* !defined EXIT_SUCCESS */
 101
 102 #ifndef EXIT_FAILURE
 103 #define EXIT_FAILURE    1
 104 #endif /* !defined EXIT_FAILURE */
 105
 106 #ifndef SECSPERMIN
 107 #define SECSPERMIN      60
 108 #endif /* !defined SECSPERMIN */
 109
 110 #ifndef MINSPERHOUR
 111 #define MINSPERHOUR     60
 112 #endif /* !defined MINSPERHOUR */
 113
 114 #ifndef SECSPERHOUR
 115 #define SECSPERHOUR     (SECSPERMIN * MINSPERHOUR)
 116 #endif /* !defined SECSPERHOUR */
 117
 118 #ifndef HOURSPERDAY
 119 #define HOURSPERDAY     24
 120 #endif /* !defined HOURSPERDAY */
 121
 122 #ifndef EPOCH_YEAR
 123 #define EPOCH_YEAR      1970
 124 #endif /* !defined EPOCH_YEAR */
 125
 126 #ifndef TM_YEAR_BASE
 127 #define TM_YEAR_BASE    1900
 128 #endif /* !defined TM_YEAR_BASE */
 129
 130 #ifndef DAYSPERNYEAR
 131 #define DAYSPERNYEAR    365
 132 #endif /* !defined DAYSPERNYEAR */
 133
 134 #ifndef isleap
 135 #define isleap(y) (((y) % 4) == 0 && (((y) % 100) != 0 || ((y) % 400) == 0))
 136 #endif /* !defined isleap */
 137
 138 #ifndef isleap_sum
 139 /*
 140 ** See tzfile.h for details on isleap_sum.
 141 */
 142 #define isleap_sum(a, b)        isleap((a) % 400 + (b) % 400)
 143 #endif /* !defined isleap_sum */
 144
 145 #define SECSPERDAY      ((int_fast32_t) SECSPERHOUR * HOURSPERDAY)
 146 #define SECSPERNYEAR    (SECSPERDAY * DAYSPERNYEAR)
 147 #define SECSPERLYEAR    (SECSPERNYEAR + SECSPERDAY)
 148 #define SECSPER400YEARS (SECSPERNYEAR * (intmax_t) (300 + 3)    \
 149                          + SECSPERLYEAR * (intmax_t) (100 - 3))
 150
 151 /*
 152 ** True if SECSPER400YEARS is known to be representable as an
 153 ** intmax_t.  It's OK that SECSPER400YEARS_FITS can in theory be false
 154 ** even if SECSPER400YEARS is representable, because when that happens
 155 ** the code merely runs a bit more slowly, and this slowness doesn't
 156 ** occur on any practical platform.
 157 */
 158 enum { SECSPER400YEARS_FITS = SECSPERLYEAR <= INTMAX_MAX / 400 };
 159
 160 #ifndef HAVE_GETTEXT
 161 #define HAVE_GETTEXT 0
 162 #endif
 163 #if HAVE_GETTEXT
 164 #include "locale.h"     /* for setlocale */
 165 #include "libintl.h"
 166 #endif /* HAVE_GETTEXT */
 167
 168 #ifndef GNUC_or_lint
 169 #ifdef lint
 170 #define GNUC_or_lint
 171 #else /* !defined lint */
 172 #ifdef __GNUC__
 173 #define GNUC_or_lint
 174 #endif /* defined __GNUC__ */
 175 #endif /* !defined lint */
 176 #endif /* !defined GNUC_or_lint */
 177
 178 #if 2 < __GNUC__ || (__GNUC__ == 2 && 96 <= __GNUC_MINOR__)
 179 # define ATTRIBUTE_PURE __attribute__ ((__pure__))
 180 #else
 181 # define ATTRIBUTE_PURE /* empty */
 182 #endif
 183
 184 /*
 185 ** For the benefit of GNU folk...
 186 ** `_(MSGID)' uses the current locale's message library string for MSGID.
 187 ** The default is to use gettext if available, and use MSGID otherwise.
 188 */
 189
 190 #ifndef _
 191 #if HAVE_GETTEXT
 192 #define _(msgid) gettext(msgid)
 193 #else /* !HAVE_GETTEXT */
 194 #define _(msgid) msgid
 195 #endif /* !HAVE_GETTEXT */
 196 #endif /* !defined _ */
 197
 198 #ifndef TZ_DOMAIN
 199 #define TZ_DOMAIN "tz"
 200 #endif /* !defined TZ_DOMAIN */
 201
 202 extern char **  environ;
 203 extern int      getopt(int argc, char * const argv[],
 204                         const char * options);
 205 extern char *   optarg;
 206 extern int      optind;
 207 extern char *   tzname[2];
 208
 209 /* The minimum and maximum finite time values.  */
 210 static time_t const absolute_min_time =
 211   ((time_t) -1 < 0
 212    ? (time_t) -1 << (CHAR_BIT * sizeof (time_t) - 1)
 213    : 0);
 214 static time_t const absolute_max_time =
 215   ((time_t) -1 < 0
 216    ? - (~ 0 < 0) - ((time_t) -1 << (CHAR_BIT * sizeof (time_t) - 1))
 217    : -1);
 218 static size_t   longest;
 219 static char *   progname;
 220 static int      warned;
 221
 222 static char *   abbr(struct tm * tmp);
 223 static void     abbrok(const char * abbrp, const char * zone);
 224 static intmax_t delta(struct tm * newp, struct tm * oldp) ATTRIBUTE_PURE;
 225 static void     dumptime(const struct tm * tmp);
 226 static time_t   hunt(char * name, time_t lot, time_t    hit);
 227 static void     show(char * zone, time_t t, int v);
 228 static const char *     tformat(void);
 229 static time_t   yeartot(intmax_t y) ATTRIBUTE_PURE;
 230
 231 #ifndef TYPECHECK
 232 #define my_localtime    localtime
 233 #else /* !defined TYPECHECK */
 234 static struct tm *
 235 my_localtime(time_t *tp)
 236 {
 237         register struct tm *    tmp;
 238
 239         tmp = localtime(tp);
 240         if (tp != NULL && tmp != NULL) {
 241                 struct tm       tm;
 242                 register time_t t;
 243
 244                 tm = *tmp;
 245                 t = mktime(&tm);
 246                 if (t != *tp) {
 247                         (void) fflush(stdout);
 248                         (void) fprintf(stderr, "\n%s: ", progname);
 249                         (void) fprintf(stderr, tformat(), *tp);
 250                         (void) fprintf(stderr, " ->");
 251                         (void) fprintf(stderr, " year=%d", tmp->tm_year);
 252                         (void) fprintf(stderr, " mon=%d", tmp->tm_mon);
 253                         (void) fprintf(stderr, " mday=%d", tmp->tm_mday);
 254                         (void) fprintf(stderr, " hour=%d", tmp->tm_hour);
 255                         (void) fprintf(stderr, " min=%d", tmp->tm_min);
 256                         (void) fprintf(stderr, " sec=%d", tmp->tm_sec);
 257                         (void) fprintf(stderr, " isdst=%d", tmp->tm_isdst);
 258                         (void) fprintf(stderr, " -> ");
 259                         (void) fprintf(stderr, tformat(), t);
 260                         (void) fprintf(stderr, "\n");
 261                 }
 262         }
 263         return tmp;
 264 }
 265 #endif /* !defined TYPECHECK */
 266
 267 static void
 268 abbrok(const char *const abbrp, const char *const zone)
 269 {
 270         register const char *   cp;
 271         register const char *   wp;
 272
 273         if (warned)
 274                 return;
 275         cp = abbrp;
 276         wp = NULL;
 277         while (isascii((unsigned char) *cp) && isalpha((unsigned char) *cp))
 278                 ++cp;
 279         if (cp - abbrp == 0)
 280                 wp = _("lacks alphabetic at start");
 281         else if (cp - abbrp < 3)
 282                 wp = _("has fewer than 3 alphabetics");
 283         else if (cp - abbrp > 6)
 284                 wp = _("has more than 6 alphabetics");
 285         if (wp == NULL && (*cp == '+' || *cp == '-')) {
 286                 ++cp;
 287                 if (isascii((unsigned char) *cp) &&
 288                         isdigit((unsigned char) *cp))
 289                                 if (*cp++ == '1' && *cp >= '0' && *cp <= '4')
 290                                         ++cp;
 291                 if (*cp != '\0')
 292                         wp = _("differs from POSIX standard");
 293         }
 294         if (wp == NULL)
 295                 return;
 296         (void) fflush(stdout);
 297         (void) fprintf(stderr,
 298                 _("%s: warning: zone \"%s\" abbreviation \"%s\" %s\n"),
 299                 progname, zone, abbrp, wp);
 300         warned = TRUE;
 301 }
 302
 303 static void
 304 usage(FILE * const stream, const int status)
 305 {
 306         (void) fprintf(stream,
 307 _("%s: usage: %s [--version] [--help] [-{vV}] [-{ct} [lo,]hi] zonename ...\n"
 308   "\n"
 309   "Report bugs to %s.\n"),
 310                        progname, progname, REPORT_BUGS_TO);
 311         exit(status);
 312 }
 313
 314 int
 315 main(int argc, char *argv[])
 316 {
 317         register int            i;
 318         register int            vflag;
 319         register int            Vflag;
 320         register char *         cutarg;
 321         register char *         cuttimes;
 322         register time_t         cutlotime;
 323         register time_t         cuthitime;
 324         register char **        fakeenv;
 325         time_t                  now;
 326         time_t                  t;
 327         time_t                  newt;
 328         struct tm               tm;
 329         struct tm               newtm;
 330         register struct tm *    tmp;
 331         register struct tm *    newtmp;
 332
 333         cutlotime = absolute_min_time;
 334         cuthitime = absolute_max_time;
 335 #if HAVE_GETTEXT
 336         (void) setlocale(LC_ALL, "");
 337 #ifdef TZ_DOMAINDIR
 338         (void) bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR);
 339 #endif /* defined TEXTDOMAINDIR */
 340         (void) textdomain(TZ_DOMAIN);
 341 #endif /* HAVE_GETTEXT */
 342         progname = argv[0];
 343         for (i = 1; i < argc; ++i)
 344                 if (strcmp(argv[i], "--version") == 0) {
 345                         (void) printf("zdump %s%s\n", PKGVERSION, TZVERSION);
 346                         exit(EXIT_SUCCESS);
 347                 } else if (strcmp(argv[i], "--help") == 0) {
 348                         usage(stdout, EXIT_SUCCESS);
 349                 }
 350         vflag = Vflag = 0;
 351         cutarg = cuttimes = NULL;
 352         for (;;)
 353           switch (getopt(argc, argv, "c:t:vV")) {
 354           case 'c': cutarg = optarg; break;
 355           case 't': cuttimes = optarg; break;
 356           case 'v': vflag = 1; break;
 357           case 'V': Vflag = 1; break;
 358           case -1:
 359             if (! (optind == argc - 1 && strcmp(argv[optind], "=") == 0))
 360               goto arg_processing_done;
 361             /* Fall through.  */
 362           default:
 363             usage(stderr, EXIT_FAILURE);
 364           }
 365  arg_processing_done:;
 366
 367         if (vflag | Vflag) {
 368                 intmax_t        lo;
 369                 intmax_t        hi;
 370                 char *loend, *hiend;
 371                 register intmax_t cutloyear = ZDUMP_LO_YEAR;
 372                 register intmax_t cuthiyear = ZDUMP_HI_YEAR;
 373                 if (cutarg != NULL) {
 374                         lo = strtoimax(cutarg, &loend, 10);
 375                         if (cutarg != loend && !*loend) {
 376                                 hi = lo;
 377                                 cuthiyear = hi;
 378                         } else if (cutarg != loend && *loend == ','
 379                                    && (hi = strtoimax(loend + 1, &hiend, 10),
 380                                        loend + 1 != hiend && !*hiend)) {
 381                                 cutloyear = lo;
 382                                 cuthiyear = hi;
 383                         } else {
 384 (void) fprintf(stderr, _("%s: wild -c argument %s\n"),
 385                                         progname, cutarg);
 386                                 exit(EXIT_FAILURE);
 387                         }
 388                 }
 389                 if (cutarg != NULL || cuttimes == NULL) {
 390                         cutlotime = yeartot(cutloyear);
 391                         cuthitime = yeartot(cuthiyear);
 392                 }
 393                 if (cuttimes != NULL) {
 394                         lo = strtoimax(cuttimes, &loend, 10);
 395                         if (cuttimes != loend && !*loend) {
 396                                 hi = lo;
 397                                 if (hi < cuthitime) {
 398                                         if (hi < absolute_min_time)
 399                                                 hi = absolute_min_time;
 400                                         cuthitime = hi;
 401                                 }
 402                         } else if (cuttimes != loend && *loend == ','
 403                                    && (hi = strtoimax(loend + 1, &hiend, 10),
 404                                        loend + 1 != hiend && !*hiend)) {
 405                                 if (cutlotime < lo) {
 406                                         if (absolute_max_time < lo)
 407                                                 lo = absolute_max_time;
 408                                         cutlotime = lo;
 409                                 }
 410                                 if (hi < cuthitime) {
 411                                         if (hi < absolute_min_time)
 412                                                 hi = absolute_min_time;
 413                                         cuthitime = hi;
 414                                 }
 415                         } else {
 416                                 (void) fprintf(stderr,
 417                                         _("%s: wild -t argument %s\n"),
 418                                         progname, cuttimes);
 419                                 exit(EXIT_FAILURE);
 420                         }
 421                 }
 422         }
 423         (void) time(&now);
 424         longest = 0;
 425         for (i = optind; i < argc; ++i)
 426                 if (strlen(argv[i]) > longest)
 427                         longest = strlen(argv[i]);
 428         {
 429                 register int    from;
 430                 register int    to;
 431
 432                 for (i = 0; environ[i] != NULL; ++i)
 433                         continue;
 434                 fakeenv = malloc((i + 2) * sizeof *fakeenv);
 435                 if (fakeenv == NULL
 436                     || (fakeenv[0] = malloc(longest + 4)) == NULL) {
 437                                         (void) perror(progname);
 438                                         exit(EXIT_FAILURE);
 439                 }
 440                 to = 0;
 441                 (void) strcpy(fakeenv[to++], "TZ=");
 442                 for (from = 0; environ[from] != NULL; ++from)
 443                         if (strncmp(environ[from], "TZ=", 3) != 0)
 444                                 fakeenv[to++] = environ[from];
 445                 fakeenv[to] = NULL;
 446                 environ = fakeenv;
 447         }
 448         for (i = optind; i < argc; ++i) {
 449                 static char     buf[MAX_STRING_LENGTH];
 450
 451                 (void) strcpy(&fakeenv[0][3], argv[i]);
 452                 if (! (vflag | Vflag)) {
 453                         show(argv[i], now, FALSE);
 454                         continue;
 455                 }
 456                 warned = FALSE;
 457                 t = absolute_min_time;
 458                 if (!Vflag) {
 459                         show(argv[i], t, TRUE);
 460                         t += SECSPERDAY;
 461                         show(argv[i], t, TRUE);
 462                 }
 463                 if (t < cutlotime)
 464                         t = cutlotime;
 465                 tmp = my_localtime(&t);
 466                 if (tmp != NULL) {
 467                         tm = *tmp;
 468                         (void) strncpy(buf, abbr(&tm), (sizeof buf) - 1);
 469                 }
 470                 for ( ; ; ) {
 471                         newt = (t < absolute_max_time - SECSPERDAY / 2
 472                                 ? t + SECSPERDAY / 2
 473                                 : absolute_max_time);
 474                         if (cuthitime <= newt)
 475                                 break;
 476                         newtmp = localtime(&newt);
 477                         if (newtmp != NULL)
 478                                 newtm = *newtmp;
 479                         if ((tmp == NULL || newtmp == NULL) ? (tmp != newtmp) :
 480                                 (delta(&newtm, &tm) != (newt - t) ||
 481                                 newtm.tm_isdst != tm.tm_isdst ||
 482                                 strcmp(abbr(&newtm), buf) != 0)) {
 483                                         newt = hunt(argv[i], t, newt);
 484                                         newtmp = localtime(&newt);
 485                                         if (newtmp != NULL) {
 486                                                 newtm = *newtmp;
 487                                                 (void) strncpy(buf,
 488                                                         abbr(&newtm),
 489                                                         (sizeof buf) - 1);
 490                                         }
 491                         }
 492                         t = newt;
 493                         tm = newtm;
 494                         tmp = newtmp;
 495                 }
 496                 if (!Vflag) {
 497                         t = absolute_max_time;
 498                         t -= SECSPERDAY;
 499                         show(argv[i], t, TRUE);
 500                         t += SECSPERDAY;
 501                         show(argv[i], t, TRUE);
 502                 }
 503         }
 504         if (fflush(stdout) || ferror(stdout)) {
 505                 (void) fprintf(stderr, "%s: ", progname);
 506                 (void) perror(_("Error writing to standard output"));
 507                 exit(EXIT_FAILURE);
 508         }
 509         exit(EXIT_SUCCESS);
 510         /* If exit fails to exit... */
 511         return EXIT_FAILURE;
 512 }
 513
 514 static time_t
 515 yeartot(const intmax_t y)
 516 {
 517         register intmax_t       myy, seconds, years;
 518         register time_t         t;
 519
 520         myy = EPOCH_YEAR;
 521         t = 0;
 522         while (myy < y) {
 523                 if (SECSPER400YEARS_FITS && 400 <= y - myy) {
 524                         intmax_t diff400 = (y - myy) / 400;
 525                         if (INTMAX_MAX / SECSPER400YEARS < diff400)
 526                                 return absolute_max_time;
 527                         seconds = diff400 * SECSPER400YEARS;
 528                         years = diff400 * 400;
 529                 } else {
 530                         seconds = isleap(myy) ? SECSPERLYEAR : SECSPERNYEAR;
 531                         years = 1;
 532                 }
 533                 myy += years;
 534                 if (t > absolute_max_time - seconds)
 535                         return absolute_max_time;
 536                 t += seconds;
 537         }
 538         while (y < myy) {
 539                 if (SECSPER400YEARS_FITS && y + 400 <= myy && myy < 0) {
 540                         intmax_t diff400 = (myy - y) / 400;
 541                         if (INTMAX_MAX / SECSPER400YEARS < diff400)
 542                                 return absolute_min_time;
 543                         seconds = diff400 * SECSPER400YEARS;
 544                         years = diff400 * 400;
 545                 } else {
 546                         seconds = isleap(myy - 1) ? SECSPERLYEAR : SECSPERNYEAR;
 547                         years = 1;
 548                 }
 549                 myy -= years;
 550                 if (t < absolute_min_time + seconds)
 551                         return absolute_min_time;
 552                 t -= seconds;
 553         }
 554         return t;
 555 }
 556
 557 static time_t
 558 hunt(char *name, time_t lot, time_t hit)
 559 {
 560         time_t                  t;
 561         struct tm               lotm;
 562         register struct tm *    lotmp;
 563         struct tm               tm;
 564         register struct tm *    tmp;
 565         char                    loab[MAX_STRING_LENGTH];
 566
 567         lotmp = my_localtime(&lot);
 568         if (lotmp != NULL) {
 569                 lotm = *lotmp;
 570                 (void) strncpy(loab, abbr(&lotm), (sizeof loab) - 1);
 571         }
 572         for ( ; ; ) {
 573                 time_t diff = hit - lot;
 574                 if (diff < 2)
 575                         break;
 576                 t = lot;
 577                 t += diff / 2;
 578                 if (t <= lot)
 579                         ++t;
 580                 else if (t >= hit)
 581                         --t;
 582                 tmp = my_localtime(&t);
 583                 if (tmp != NULL)
 584                         tm = *tmp;
 585                 if ((lotmp == NULL || tmp == NULL) ? (lotmp == tmp) :
 586                         (delta(&tm, &lotm) == (t - lot) &&
 587                         tm.tm_isdst == lotm.tm_isdst &&
 588                         strcmp(abbr(&tm), loab) == 0)) {
 589                                 lot = t;
 590                                 lotm = tm;
 591                                 lotmp = tmp;
 592                 } else  hit = t;
 593         }
 594         show(name, lot, TRUE);
 595         show(name, hit, TRUE);
 596         return hit;
 597 }
 598
 599 /*
 600 ** Thanks to Paul Eggert for logic used in delta.
 601 */
 602
 603 static intmax_t
 604 delta(struct tm * newp, struct tm *oldp)
 605 {
 606         register intmax_t       result;
 607         register int            tmy;
 608
 609         if (newp->tm_year < oldp->tm_year)
 610                 return -delta(oldp, newp);
 611         result = 0;
 612         for (tmy = oldp->tm_year; tmy < newp->tm_year; ++tmy)
 613                 result += DAYSPERNYEAR + isleap_sum(tmy, TM_YEAR_BASE);
 614         result += newp->tm_yday - oldp->tm_yday;
 615         result *= HOURSPERDAY;
 616         result += newp->tm_hour - oldp->tm_hour;
 617         result *= MINSPERHOUR;
 618         result += newp->tm_min - oldp->tm_min;
 619         result *= SECSPERMIN;
 620         result += newp->tm_sec - oldp->tm_sec;
 621         return result;
 622 }
 623
 624 static void
 625 show(char *zone, time_t t, int v)
 626 {
 627         register struct tm *    tmp;
 628
 629         (void) printf("%-*s  ", (int) longest, zone);
 630         if (v) {
 631                 tmp = gmtime(&t);
 632                 if (tmp == NULL) {
 633                         (void) printf(tformat(), t);
 634                 } else {
 635                         dumptime(tmp);
 636                         (void) printf(" UT");
 637                 }
 638                 (void) printf(" = ");
 639         }
 640         tmp = my_localtime(&t);
 641         dumptime(tmp);
 642         if (tmp != NULL) {
 643                 if (*abbr(tmp) != '\0')
 644                         (void) printf(" %s", abbr(tmp));
 645                 if (v) {
 646                         (void) printf(" isdst=%d", tmp->tm_isdst);
 647 #ifdef TM_GMTOFF
 648                         (void) printf(" gmtoff=%ld", tmp->TM_GMTOFF);
 649 #endif /* defined TM_GMTOFF */
 650                 }
 651         }
 652         (void) printf("\n");
 653         if (tmp != NULL && *abbr(tmp) != '\0')
 654                 abbrok(abbr(tmp), zone);
 655 }
 656
 657 static char *
 658 abbr(struct tm *tmp)
 659 {
 660         register char * result;
 661         static char     nada;
 662
 663         if (tmp->tm_isdst != 0 && tmp->tm_isdst != 1)
 664                 return &nada;
 665         result = tzname[tmp->tm_isdst];
 666         return (result == NULL) ? &nada : result;
 667 }
 668
 669 /*
 670 ** The code below can fail on certain theoretical systems;
 671 ** it works on all known real-world systems as of 2004-12-30.
 672 */
 673
 674 static const char *
 675 tformat(void)
 676 {
 677         if (0 > (time_t) -1) {          /* signed */
 678                 if (sizeof (time_t) == sizeof (intmax_t))
 679                         return "%"PRIdMAX;
 680                 if (sizeof (time_t) > sizeof (long))
 681                         return "%lld";
 682                 if (sizeof (time_t) > sizeof (int))
 683                         return "%ld";
 684                 return "%d";
 685         }
 686 #ifdef PRIuMAX
 687         if (sizeof (time_t) == sizeof (uintmax_t))
 688                 return "%"PRIuMAX;
 689 #endif
 690         if (sizeof (time_t) > sizeof (unsigned long))
 691                 return "%llu";
 692         if (sizeof (time_t) > sizeof (unsigned int))
 693                 return "%lu";
 694         return "%u";
 695 }
 696
 697 static void
 698 dumptime(register const struct tm *timeptr)
 699 {
 700         static const char       wday_name[][3] = {
 701                 "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
 702         };
 703         static const char       mon_name[][3] = {
 704                 "Jan", "Feb", "Mar", "Apr", "May", "Jun",
 705                 "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
 706         };
 707         register const char *   wn;
 708         register const char *   mn;
 709         register int            lead;
 710         register int            trail;
 711
 712         if (timeptr == NULL) {
 713                 (void) printf("NULL");
 714                 return;
 715         }
 716         /*
 717         ** The packaged versions of localtime and gmtime never put out-of-range
 718         ** values in tm_wday or tm_mon, but since this code might be compiled
 719         ** with other (perhaps experimental) versions, paranoia is in order.
 720         */
 721         if (timeptr->tm_wday < 0 || timeptr->tm_wday >=
 722                 (int) (sizeof wday_name / sizeof wday_name[0]))
 723                         wn = "???";
 724         else            wn = wday_name[timeptr->tm_wday];
 725         if (timeptr->tm_mon < 0 || timeptr->tm_mon >=
 726                 (int) (sizeof mon_name / sizeof mon_name[0]))
 727                         mn = "???";
 728         else            mn = mon_name[timeptr->tm_mon];
 729         (void) printf("%.3s %.3s%3d %.2d:%.2d:%.2d ",
 730                 wn, mn,
 731                 timeptr->tm_mday, timeptr->tm_hour,
 732                 timeptr->tm_min, timeptr->tm_sec);
 733 #define DIVISOR 10
 734         trail = timeptr->tm_year % DIVISOR + TM_YEAR_BASE % DIVISOR;
 735         lead = timeptr->tm_year / DIVISOR + TM_YEAR_BASE / DIVISOR +
 736                 trail / DIVISOR;
 737         trail %= DIVISOR;
 738         if (trail < 0 && lead > 0) {
 739                 trail += DIVISOR;
 740                 --lead;
 741         } else if (lead < 0 && trail > 0) {
 742                 trail -= DIVISOR;
 743                 ++lead;
 744         }
 745         if (lead == 0)
 746                 (void) printf("%d", trail);
 747         else    (void) printf("%d%d", lead, ((trail < 0) ? -trail : trail));
 748 }