timezone/zdump.c

   1 static char     elsieid[] = "@(#)zdump.c        8.6";
   2
   3 /*
   4 ** This code has been made independent of the rest of the time
   5 ** conversion package to increase confidence in the verification it provides.
   6 ** You can use this code to help in verifying other implementations.
   7 */
   8
   9 #include "stdio.h"      /* for stdout, stderr, perror */
  10 #include "string.h"     /* for strcpy */
  11 #include "sys/types.h"  /* for time_t */
  12 #include "time.h"       /* for struct tm */
  13 #include "stdlib.h"     /* for exit, malloc, atoi */
  14 #include "float.h"      /* for FLT_MAX and DBL_MAX */
  15 #include "ctype.h"      /* for isalpha et al. */
  16 #ifndef isascii
  17 #define isascii(x) 1
  18 #endif /* !defined isascii */
  19
  20 #ifndef ZDUMP_LO_YEAR
  21 #define ZDUMP_LO_YEAR   (-500)
  22 #endif /* !defined ZDUMP_LO_YEAR */
  23
  24 #ifndef ZDUMP_HI_YEAR
  25 #define ZDUMP_HI_YEAR   2500
  26 #endif /* !defined ZDUMP_HI_YEAR */
  27
  28 #ifndef MAX_STRING_LENGTH
  29 #define MAX_STRING_LENGTH       1024
  30 #endif /* !defined MAX_STRING_LENGTH */
  31
  32 #ifndef TRUE
  33 #define TRUE            1
  34 #endif /* !defined TRUE */
  35
  36 #ifndef FALSE
  37 #define FALSE           0
  38 #endif /* !defined FALSE */
  39
  40 #ifndef EXIT_SUCCESS
  41 #define EXIT_SUCCESS    0
  42 #endif /* !defined EXIT_SUCCESS */
  43
  44 #ifndef EXIT_FAILURE
  45 #define EXIT_FAILURE    1
  46 #endif /* !defined EXIT_FAILURE */
  47
  48 #ifndef SECSPERMIN
  49 #define SECSPERMIN      60
  50 #endif /* !defined SECSPERMIN */
  51
  52 #ifndef MINSPERHOUR
  53 #define MINSPERHOUR     60
  54 #endif /* !defined MINSPERHOUR */
  55
  56 #ifndef SECSPERHOUR
  57 #define SECSPERHOUR     (SECSPERMIN * MINSPERHOUR)
  58 #endif /* !defined SECSPERHOUR */
  59
  60 #ifndef HOURSPERDAY
  61 #define HOURSPERDAY     24
  62 #endif /* !defined HOURSPERDAY */
  63
  64 #ifndef EPOCH_YEAR
  65 #define EPOCH_YEAR      1970
  66 #endif /* !defined EPOCH_YEAR */
  67
  68 #ifndef TM_YEAR_BASE
  69 #define TM_YEAR_BASE    1900
  70 #endif /* !defined TM_YEAR_BASE */
  71
  72 #ifndef DAYSPERNYEAR
  73 #define DAYSPERNYEAR    365
  74 #endif /* !defined DAYSPERNYEAR */
  75
  76 #ifndef isleap
  77 #define isleap(y) (((y) % 4) == 0 && (((y) % 100) != 0 || ((y) % 400) == 0))
  78 #endif /* !defined isleap */
  79
  80 #ifndef isleap_sum
  81 /*
  82 ** See tzfile.h for details on isleap_sum.
  83 */
  84 #define isleap_sum(a, b)        isleap((a) % 400 + (b) % 400)
  85 #endif /* !defined isleap_sum */
  86
  87 #define SECSPERDAY      ((long) SECSPERHOUR * HOURSPERDAY)
  88 #define SECSPERNYEAR    (SECSPERDAY * DAYSPERNYEAR)
  89 #define SECSPERLYEAR    (SECSPERNYEAR + SECSPERDAY)
  90
  91 #ifndef HAVE_GETTEXT
  92 #define HAVE_GETTEXT 0
  93 #endif
  94 #if HAVE_GETTEXT
  95 #include "locale.h"     /* for setlocale */
  96 #include "libintl.h"
  97 #endif /* HAVE_GETTEXT */
  98
  99 #ifndef GNUC_or_lint
 100 #ifdef lint
 101 #define GNUC_or_lint
 102 #else /* !defined lint */
 103 #ifdef __GNUC__
 104 #define GNUC_or_lint
 105 #endif /* defined __GNUC__ */
 106 #endif /* !defined lint */
 107 #endif /* !defined GNUC_or_lint */
 108
 109 #ifndef INITIALIZE
 110 #ifdef GNUC_or_lint
 111 #define INITIALIZE(x)   ((x) = 0)
 112 #else /* !defined GNUC_or_lint */
 113 #define INITIALIZE(x)
 114 #endif /* !defined GNUC_or_lint */
 115 #endif /* !defined INITIALIZE */
 116
 117 /*
 118 ** For the benefit of GNU folk...
 119 ** `_(MSGID)' uses the current locale's message library string for MSGID.
 120 ** The default is to use gettext if available, and use MSGID otherwise.
 121 */
 122
 123 #ifndef _
 124 #if HAVE_GETTEXT
 125 #define _(msgid) gettext(msgid)
 126 #else /* !HAVE_GETTEXT */
 127 #define _(msgid) msgid
 128 #endif /* !HAVE_GETTEXT */
 129 #endif /* !defined _ */
 130
 131 #ifndef TZ_DOMAIN
 132 #define TZ_DOMAIN "tz"
 133 #endif /* !defined TZ_DOMAIN */
 134
 135 extern char **  environ;
 136 extern int      getopt(int argc, char * const argv[],
 137                         const char * options);
 138 extern char *   optarg;
 139 extern int      optind;
 140 extern char *   tzname[2];
 141
 142 static time_t   absolute_min_time;
 143 static time_t   absolute_max_time;
 144 static size_t   longest;
 145 static char *   progname;
 146 static int      warned;
 147
 148 static char *   abbr(struct tm * tmp);
 149 static void     abbrok(const char * abbrp, const char * zone);
 150 static long     delta(struct tm * newp, struct tm * oldp);
 151 static void     dumptime(const struct tm * tmp);
 152 static time_t   hunt(char * name, time_t lot, time_t    hit);
 153 static void     setabsolutes(void);
 154 static void     show(char * zone, time_t t, int v);
 155 static const char *     tformat(void);
 156 static time_t   yeartot(long y);
 157
 158 #ifndef TYPECHECK
 159 #define my_localtime    localtime
 160 #else /* !defined TYPECHECK */
 161 static struct tm *
 162 my_localtime(tp)
 163 time_t *        tp;
 164 {
 165         register struct tm *    tmp;
 166
 167         tmp = localtime(tp);
 168         if (tp != NULL && tmp != NULL) {
 169                 struct tm       tm;
 170                 register time_t t;
 171
 172                 tm = *tmp;
 173                 t = mktime(&tm);
 174                 if (t - *tp >= 1 || *tp - t >= 1) {
 175                         (void) fflush(stdout);
 176                         (void) fprintf(stderr, "\n%s: ", progname);
 177                         (void) fprintf(stderr, tformat(), *tp);
 178                         (void) fprintf(stderr, " ->");
 179                         (void) fprintf(stderr, " year=%d", tmp->tm_year);
 180                         (void) fprintf(stderr, " mon=%d", tmp->tm_mon);
 181                         (void) fprintf(stderr, " mday=%d", tmp->tm_mday);
 182                         (void) fprintf(stderr, " hour=%d", tmp->tm_hour);
 183                         (void) fprintf(stderr, " min=%d", tmp->tm_min);
 184                         (void) fprintf(stderr, " sec=%d", tmp->tm_sec);
 185                         (void) fprintf(stderr, " isdst=%d", tmp->tm_isdst);
 186                         (void) fprintf(stderr, " -> ");
 187                         (void) fprintf(stderr, tformat(), t);
 188                         (void) fprintf(stderr, "\n");
 189                 }
 190         }
 191         return tmp;
 192 }
 193 #endif /* !defined TYPECHECK */
 194
 195 static void
 196 abbrok(abbrp, zone)
 197 const char * const      abbrp;
 198 const char * const      zone;
 199 {
 200         register const char *   cp;
 201         register char *         wp;
 202
 203         if (warned)
 204                 return;
 205         cp = abbrp;
 206         wp = NULL;
 207         while (isascii((unsigned char) *cp) && isalpha((unsigned char) *cp))
 208                 ++cp;
 209         if (cp - abbrp == 0)
 210                 wp = _("lacks alphabetic at start");
 211         else if (cp - abbrp < 3)
 212                 wp = _("has fewer than 3 alphabetics");
 213         else if (cp - abbrp > 6)
 214                 wp = _("has more than 6 alphabetics");
 215         if (wp == NULL && (*cp == '+' || *cp == '-')) {
 216                 ++cp;
 217                 if (isascii((unsigned char) *cp) &&
 218                         isdigit((unsigned char) *cp))
 219                                 if (*cp++ == '1' && *cp >= '0' && *cp <= '4')
 220                                         ++cp;
 221                 if (*cp != '\0')
 222                         wp = _("differs from POSIX standard");
 223         }
 224         if (wp == NULL)
 225                 return;
 226         (void) fflush(stdout);
 227         (void) fprintf(stderr,
 228                 _("%s: warning: zone \"%s\" abbreviation \"%s\" %s\n"),
 229                 progname, zone, abbrp, wp);
 230         warned = TRUE;
 231 }
 232
 233 int
 234 main(argc, argv)
 235 int     argc;
 236 char *  argv[];
 237 {
 238         register int            i;
 239         register int            c;
 240         register int            vflag;
 241         register char *         cutarg;
 242         register long           cutloyear = ZDUMP_LO_YEAR;
 243         register long           cuthiyear = ZDUMP_HI_YEAR;
 244         register time_t         cutlotime;
 245         register time_t         cuthitime;
 246         register char **        fakeenv;
 247         time_t                  now;
 248         time_t                  t;
 249         time_t                  newt;
 250         struct tm               tm;
 251         struct tm               newtm;
 252         register struct tm *    tmp;
 253         register struct tm *    newtmp;
 254
 255         INITIALIZE(cutlotime);
 256         INITIALIZE(cuthitime);
 257 #if HAVE_GETTEXT
 258         (void) setlocale(LC_ALL, "");
 259 #ifdef TZ_DOMAINDIR
 260         (void) bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR);
 261 #endif /* defined TEXTDOMAINDIR */
 262         (void) textdomain(TZ_DOMAIN);
 263 #endif /* HAVE_GETTEXT */
 264         progname = argv[0];
 265         for (i = 1; i < argc; ++i)
 266                 if (strcmp(argv[i], "--version") == 0) {
 267                         (void) printf("%s\n", elsieid);
 268                         exit(EXIT_SUCCESS);
 269                 }
 270         vflag = 0;
 271         cutarg = NULL;
 272         while ((c = getopt(argc, argv, "c:v")) == 'c' || c == 'v')
 273                 if (c == 'v')
 274                         vflag = 1;
 275                 else    cutarg = optarg;
 276         if ((c != EOF && c != -1) ||
 277                 (optind == argc - 1 && strcmp(argv[optind], "=") == 0)) {
 278                         (void) fprintf(stderr,
 279 _("%s: usage is %s [ --version ] [ -v ] [ -c [loyear,]hiyear ] zonename ...\n"),
 280                                 progname, progname);
 281                         exit(EXIT_FAILURE);
 282         }
 283         if (vflag) {
 284                 if (cutarg != NULL) {
 285                         long    lo;
 286                         long    hi;
 287                         char    dummy;
 288
 289                         if (sscanf(cutarg, "%ld%c", &hi, &dummy) == 1) {
 290                                 cuthiyear = hi;
 291                         } else if (sscanf(cutarg, "%ld,%ld%c",
 292                                 &lo, &hi, &dummy) == 2) {
 293                                         cutloyear = lo;
 294                                         cuthiyear = hi;
 295                         } else {
 296 (void) fprintf(stderr, _("%s: wild -c argument %s\n"),
 297                                         progname, cutarg);
 298                                 exit(EXIT_FAILURE);
 299                         }
 300                 }
 301                 setabsolutes();
 302                 cutlotime = yeartot(cutloyear);
 303                 cuthitime = yeartot(cuthiyear);
 304         }
 305         (void) time(&now);
 306         longest = 0;
 307         for (i = optind; i < argc; ++i)
 308                 if (strlen(argv[i]) > longest)
 309                         longest = strlen(argv[i]);
 310         {
 311                 register int    from;
 312                 register int    to;
 313
 314                 for (i = 0; environ[i] != NULL; ++i)
 315                         continue;
 316                 fakeenv = (char **) malloc((size_t) ((i + 2) *
 317                         sizeof *fakeenv));
 318                 if (fakeenv == NULL ||
 319                         (fakeenv[0] = (char *) malloc(longest + 4)) == NULL) {
 320                                         (void) perror(progname);
 321                                         exit(EXIT_FAILURE);
 322                 }
 323                 to = 0;
 324                 (void) strcpy(fakeenv[to++], "TZ=");
 325                 for (from = 0; environ[from] != NULL; ++from)
 326                         if (strncmp(environ[from], "TZ=", 3) != 0)
 327                                 fakeenv[to++] = environ[from];
 328                 fakeenv[to] = NULL;
 329                 environ = fakeenv;
 330         }
 331         for (i = optind; i < argc; ++i) {
 332                 static char     buf[MAX_STRING_LENGTH];
 333
 334                 (void) strcpy(&fakeenv[0][3], argv[i]);
 335                 if (!vflag) {
 336                         show(argv[i], now, FALSE);
 337                         continue;
 338                 }
 339                 warned = FALSE;
 340                 t = absolute_min_time;
 341                 show(argv[i], t, TRUE);
 342                 t += SECSPERHOUR * HOURSPERDAY;
 343                 show(argv[i], t, TRUE);
 344                 if (t < cutlotime)
 345                         t = cutlotime;
 346                 tmp = my_localtime(&t);
 347                 if (tmp != NULL) {
 348                         tm = *tmp;
 349                         (void) strncpy(buf, abbr(&tm), (sizeof buf) - 1);
 350                 }
 351                 for ( ; ; ) {
 352                         if (t >= cuthitime)
 353                                 break;
 354                         newt = t + SECSPERHOUR * 12;
 355                         if (newt >= cuthitime)
 356                                 break;
 357                         if (newt <= t)
 358                                 break;
 359                         newtmp = localtime(&newt);
 360                         if (newtmp != NULL)
 361                                 newtm = *newtmp;
 362                         if ((tmp == NULL || newtmp == NULL) ? (tmp != newtmp) :
 363                                 (delta(&newtm, &tm) != (newt - t) ||
 364                                 newtm.tm_isdst != tm.tm_isdst ||
 365                                 strcmp(abbr(&newtm), buf) != 0)) {
 366                                         newt = hunt(argv[i], t, newt);
 367                                         newtmp = localtime(&newt);
 368                                         if (newtmp != NULL) {
 369                                                 newtm = *newtmp;
 370                                                 (void) strncpy(buf,
 371                                                         abbr(&newtm),
 372                                                         (sizeof buf) - 1);
 373                                         }
 374                         }
 375                         t = newt;
 376                         tm = newtm;
 377                         tmp = newtmp;
 378                 }
 379                 t = absolute_max_time;
 380                 t -= SECSPERHOUR * HOURSPERDAY;
 381                 show(argv[i], t, TRUE);
 382                 t += SECSPERHOUR * HOURSPERDAY;
 383                 show(argv[i], t, TRUE);
 384         }
 385         if (fflush(stdout) || ferror(stdout)) {
 386                 (void) fprintf(stderr, "%s: ", progname);
 387                 (void) perror(_("Error writing to standard output"));
 388                 exit(EXIT_FAILURE);
 389         }
 390         exit(EXIT_SUCCESS);
 391         /* If exit fails to exit... */
 392         return EXIT_FAILURE;
 393 }
 394
 395 static void
 396 setabsolutes(void)
 397 {
 398         if (0.5 == (time_t) 0.5) {
 399                 /*
 400                 ** time_t is floating.
 401                 */
 402                 if (sizeof (time_t) == sizeof (float)) {
 403                         absolute_min_time = (time_t) -FLT_MAX;
 404                         absolute_max_time = (time_t) FLT_MAX;
 405                 } else if (sizeof (time_t) == sizeof (double)) {
 406                         absolute_min_time = (time_t) -DBL_MAX;
 407                         absolute_max_time = (time_t) DBL_MAX;
 408                 } else {
 409                         (void) fprintf(stderr,
 410 _("%s: use of -v on system with floating time_t other than float or double\n"),
 411                                 progname);
 412                         exit(EXIT_FAILURE);
 413                 }
 414         } else if (0 > (time_t) -1) {
 415                 /*
 416                 ** time_t is signed.  Assume overflow wraps around.
 417                 */
 418                 time_t t = 0;
 419                 time_t t1 = 1;
 420
 421                 while (t < t1) {
 422                         t = t1;
 423                         t1 = 2 * t1 + 1;
 424                 }
 425
 426                 absolute_max_time = t;
 427                 t = -t;
 428                 absolute_min_time = t - 1;
 429                 if (t < absolute_min_time)
 430                         absolute_min_time = t;
 431         } else {
 432                 /*
 433                 ** time_t is unsigned.
 434                 */
 435                 absolute_min_time = 0;
 436                 absolute_max_time = absolute_min_time - 1;
 437         }
 438 }
 439
 440 static time_t
 441 yeartot(y)
 442 const long      y;
 443 {
 444         register long   myy;
 445         register long   seconds;
 446         register time_t t;
 447
 448         myy = EPOCH_YEAR;
 449         t = 0;
 450         while (myy != y) {
 451                 if (myy < y) {
 452                         seconds = isleap(myy) ? SECSPERLYEAR : SECSPERNYEAR;
 453                         ++myy;
 454                         if (t > absolute_max_time - seconds) {
 455                                 t = absolute_max_time;
 456                                 break;
 457                         }
 458                         t += seconds;
 459                 } else {
 460                         --myy;
 461                         seconds = isleap(myy) ? SECSPERLYEAR : SECSPERNYEAR;
 462                         if (t < absolute_min_time + seconds) {
 463                                 t = absolute_min_time;
 464                                 break;
 465                         }
 466                         t -= seconds;
 467                 }
 468         }
 469         return t;
 470 }
 471
 472 static time_t
 473 hunt(char *name, time_t lot, time_t hit)
 474 {
 475         time_t                  t;
 476         long                    diff;
 477         struct tm               lotm;
 478         register struct tm *    lotmp;
 479         struct tm               tm;
 480         register struct tm *    tmp;
 481         char                    loab[MAX_STRING_LENGTH];
 482
 483         lotmp = my_localtime(&lot);
 484         if (lotmp != NULL) {
 485                 lotm = *lotmp;
 486                 (void) strncpy(loab, abbr(&lotm), (sizeof loab) - 1);
 487         }
 488         for ( ; ; ) {
 489                 diff = (long) (hit - lot);
 490                 if (diff < 2)
 491                         break;
 492                 t = lot;
 493                 t += diff / 2;
 494                 if (t <= lot)
 495                         ++t;
 496                 else if (t >= hit)
 497                         --t;
 498                 tmp = my_localtime(&t);
 499                 if (tmp != NULL)
 500                         tm = *tmp;
 501                 if ((lotmp == NULL || tmp == NULL) ? (lotmp == tmp) :
 502                         (delta(&tm, &lotm) == (t - lot) &&
 503                         tm.tm_isdst == lotm.tm_isdst &&
 504                         strcmp(abbr(&tm), loab) == 0)) {
 505                                 lot = t;
 506                                 lotm = tm;
 507                                 lotmp = tmp;
 508                 } else  hit = t;
 509         }
 510         show(name, lot, TRUE);
 511         show(name, hit, TRUE);
 512         return hit;
 513 }
 514
 515 /*
 516 ** Thanks to Paul Eggert for logic used in delta.
 517 */
 518
 519 static long
 520 delta(newp, oldp)
 521 struct tm *     newp;
 522 struct tm *     oldp;
 523 {
 524         register long   result;
 525         register int    tmy;
 526
 527         if (newp->tm_year < oldp->tm_year)
 528                 return -delta(oldp, newp);
 529         result = 0;
 530         for (tmy = oldp->tm_year; tmy < newp->tm_year; ++tmy)
 531                 result += DAYSPERNYEAR + isleap_sum(tmy, TM_YEAR_BASE);
 532         result += newp->tm_yday - oldp->tm_yday;
 533         result *= HOURSPERDAY;
 534         result += newp->tm_hour - oldp->tm_hour;
 535         result *= MINSPERHOUR;
 536         result += newp->tm_min - oldp->tm_min;
 537         result *= SECSPERMIN;
 538         result += newp->tm_sec - oldp->tm_sec;
 539         return result;
 540 }
 541
 542 static void
 543 show(char *zone, time_t t, int v)
 544 {
 545         register struct tm *    tmp;
 546
 547         (void) printf("%-*s  ", (int) longest, zone);
 548         if (v) {
 549                 tmp = gmtime(&t);
 550                 if (tmp == NULL) {
 551                         (void) printf(tformat(), t);
 552                 } else {
 553                         dumptime(tmp);
 554                         (void) printf(" UTC");
 555                 }
 556                 (void) printf(" = ");
 557         }
 558         tmp = my_localtime(&t);
 559         dumptime(tmp);
 560         if (tmp != NULL) {
 561                 if (*abbr(tmp) != '\0')
 562                         (void) printf(" %s", abbr(tmp));
 563                 if (v) {
 564                         (void) printf(" isdst=%d", tmp->tm_isdst);
 565 #ifdef TM_GMTOFF
 566                         (void) printf(" gmtoff=%ld", tmp->TM_GMTOFF);
 567 #endif /* defined TM_GMTOFF */
 568                 }
 569         }
 570         (void) printf("\n");
 571         if (tmp != NULL && *abbr(tmp) != '\0')
 572                 abbrok(abbr(tmp), zone);
 573 }
 574
 575 static char *
 576 abbr(tmp)
 577 struct tm *     tmp;
 578 {
 579         register char * result;
 580         static char     nada;
 581
 582         if (tmp->tm_isdst != 0 && tmp->tm_isdst != 1)
 583                 return &nada;
 584         result = tzname[tmp->tm_isdst];
 585         return (result == NULL) ? &nada : result;
 586 }
 587
 588 /*
 589 ** The code below can fail on certain theoretical systems;
 590 ** it works on all known real-world systems as of 2004-12-30.
 591 */
 592
 593 static const char *
 594 tformat(void)
 595 {
 596         if (0.5 == (time_t) 0.5) {      /* floating */
 597                 if (sizeof (time_t) > sizeof (double))
 598                         return "%Lg";
 599                 return "%g";
 600         }
 601         if (0 > (time_t) -1) {          /* signed */
 602                 if (sizeof (time_t) > sizeof (long))
 603                         return "%lld";
 604                 if (sizeof (time_t) > sizeof (int))
 605                         return "%ld";
 606                 return "%d";
 607         }
 608         if (sizeof (time_t) > sizeof (unsigned long))
 609                 return "%llu";
 610         if (sizeof (time_t) > sizeof (unsigned int))
 611                 return "%lu";
 612         return "%u";
 613 }
 614
 615 static void
 616 dumptime(timeptr)
 617 register const struct tm *      timeptr;
 618 {
 619         static const char       wday_name[][3] = {
 620                 "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
 621         };
 622         static const char       mon_name[][3] = {
 623                 "Jan", "Feb", "Mar", "Apr", "May", "Jun",
 624                 "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
 625         };
 626         register const char *   wn;
 627         register const char *   mn;
 628         register int            lead;
 629         register int            trail;
 630
 631         if (timeptr == NULL) {
 632                 (void) printf("NULL");
 633                 return;
 634         }
 635         /*
 636         ** The packaged versions of localtime and gmtime never put out-of-range
 637         ** values in tm_wday or tm_mon, but since this code might be compiled
 638         ** with other (perhaps experimental) versions, paranoia is in order.
 639         */
 640         if (timeptr->tm_wday < 0 || timeptr->tm_wday >=
 641                 (int) (sizeof wday_name / sizeof wday_name[0]))
 642                         wn = "???";
 643         else            wn = wday_name[timeptr->tm_wday];
 644         if (timeptr->tm_mon < 0 || timeptr->tm_mon >=
 645                 (int) (sizeof mon_name / sizeof mon_name[0]))
 646                         mn = "???";
 647         else            mn = mon_name[timeptr->tm_mon];
 648         (void) printf("%.3s %.3s%3d %.2d:%.2d:%.2d ",
 649                 wn, mn,
 650                 timeptr->tm_mday, timeptr->tm_hour,
 651                 timeptr->tm_min, timeptr->tm_sec);
 652 #define DIVISOR 10
 653         trail = timeptr->tm_year % DIVISOR + TM_YEAR_BASE % DIVISOR;
 654         lead = timeptr->tm_year / DIVISOR + TM_YEAR_BASE / DIVISOR +
 655                 trail / DIVISOR;
 656         trail %= DIVISOR;
 657         if (trail < 0 && lead > 0) {
 658                 trail += DIVISOR;
 659                 --lead;
 660         } else if (lead < 0 && trail > 0) {
 661                 trail -= DIVISOR;
 662                 ++lead;
 663         }
 664         if (lead == 0)
 665                 (void) printf("%d", trail);
 666         else    (void) printf("%d%d", lead, ((trail < 0) ? -trail : trail));
 667 }