timezone/zdump.c

   1 static char     elsieid[] = "@(#)zdump.c        8.4";
   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 #if HAVE_GETTEXT
  92 #include "locale.h"     /* for setlocale */
  93 #include "libintl.h"
  94 #endif /* HAVE_GETTEXT */
  95
  96 #ifndef GNUC_or_lint
  97 #ifdef lint
  98 #define GNUC_or_lint
  99 #else /* !defined lint */
 100 #ifdef __GNUC__
 101 #define GNUC_or_lint
 102 #endif /* defined __GNUC__ */
 103 #endif /* !defined lint */
 104 #endif /* !defined GNUC_or_lint */
 105
 106 #ifndef INITIALIZE
 107 #ifdef GNUC_or_lint
 108 #define INITIALIZE(x)   ((x) = 0)
 109 #else /* !defined GNUC_or_lint */
 110 #define INITIALIZE(x)
 111 #endif /* !defined GNUC_or_lint */
 112 #endif /* !defined INITIALIZE */
 113
 114 /*
 115 ** For the benefit of GNU folk...
 116 ** `_(MSGID)' uses the current locale's message library string for MSGID.
 117 ** The default is to use gettext if available, and use MSGID otherwise.
 118 */
 119
 120 #ifndef _
 121 #if HAVE_GETTEXT
 122 #define _(msgid) gettext(msgid)
 123 #else /* !HAVE_GETTEXT */
 124 #define _(msgid) msgid
 125 #endif /* !HAVE_GETTEXT */
 126 #endif /* !defined _ */
 127
 128 #ifndef TZ_DOMAIN
 129 #define TZ_DOMAIN "tz"
 130 #endif /* !defined TZ_DOMAIN */
 131
 132 #ifndef P
 133 #define P(x)    x
 134 #endif /* !defined P */
 135
 136 extern char **  environ;
 137 extern int      getopt P((int argc, char * const argv[],
 138                         const char * options));
 139 extern char *   optarg;
 140 extern int      optind;
 141 extern char *   tzname[2];
 142
 143 static time_t   absolute_min_time;
 144 static time_t   absolute_max_time;
 145 static size_t   longest;
 146 static char *   progname;
 147 static int      warned;
 148
 149 static char *   abbr P((struct tm * tmp));
 150 static void     abbrok P((const char * abbrp, const char * zone));
 151 static long     delta P((struct tm * newp, struct tm * oldp));
 152 static void     dumptime P((const struct tm * tmp));
 153 static time_t   hunt P((char * name, time_t lot, time_t hit));
 154 static void     setabsolutes P((void));
 155 static void     show P((char * zone, time_t t, int v));
 156 static const char *     tformat P((void));
 157 static time_t   yeartot P((long y));
 158
 159 #ifndef TYPECHECK
 160 #define my_localtime    localtime
 161 #else /* !defined TYPECHECK */
 162 static struct tm *
 163 my_localtime(tp)
 164 time_t *        tp;
 165 {
 166         register struct tm *    tmp;
 167
 168         tmp = localtime(tp);
 169         if (tp != NULL && tmp != NULL) {
 170                 struct tm       tm;
 171                 register time_t t;
 172
 173                 tm = *tmp;
 174                 t = mktime(&tm);
 175                 if (t - *tp >= 1 || *tp - t >= 1) {
 176                         (void) fflush(stdout);
 177                         (void) fprintf(stderr, "\n%s: ", progname);
 178                         (void) fprintf(stderr, tformat(), *tp);
 179                         (void) fprintf(stderr, " ->");
 180                         (void) fprintf(stderr, " year=%d", tmp->tm_year);
 181                         (void) fprintf(stderr, " mon=%d", tmp->tm_mon);
 182                         (void) fprintf(stderr, " mday=%d", tmp->tm_mday);
 183                         (void) fprintf(stderr, " hour=%d", tmp->tm_hour);
 184                         (void) fprintf(stderr, " min=%d", tmp->tm_min);
 185                         (void) fprintf(stderr, " sec=%d", tmp->tm_sec);
 186                         (void) fprintf(stderr, " isdst=%d", tmp->tm_isdst);
 187                         (void) fprintf(stderr, " -> ");
 188                         (void) fprintf(stderr, tformat(), t);
 189                         (void) fprintf(stderr, "\n");
 190                 }
 191         }
 192         return tmp;
 193 }
 194 #endif /* !defined TYPECHECK */
 195
 196 static void
 197 abbrok(abbrp, zone)
 198 const char * const      abbrp;
 199 const char * const      zone;
 200 {
 201         register const char *   cp;
 202         register char *         wp;
 203
 204         if (warned)
 205                 return;
 206         cp = abbrp;
 207         wp = NULL;
 208         while (isascii((unsigned char) *cp) && isalpha((unsigned char) *cp))
 209                 ++cp;
 210         if (cp - abbrp == 0)
 211                 wp = _("lacks alphabetic at start");
 212         else if (cp - abbrp < 3)
 213                 wp = _("has fewer than 3 alphabetics");
 214         else if (cp - abbrp > 6)
 215                 wp = _("has more than 6 alphabetics");
 216         if (wp == NULL && (*cp == '+' || *cp == '-')) {
 217                 ++cp;
 218                 if (isascii((unsigned char) *cp) &&
 219                         isdigit((unsigned char) *cp))
 220                                 if (*cp++ == '1' && *cp >= '0' && *cp <= '4')
 221                                         ++cp;
 222                 if (*cp != '\0')
 223                         wp = _("differs from POSIX standard");
 224         }
 225         if (wp == NULL)
 226                 return;
 227         (void) fflush(stdout);
 228         (void) fprintf(stderr,
 229                 _("%s: warning: zone \"%s\" abbreviation \"%s\" %s\n"),
 230                 progname, zone, abbrp, wp);
 231         warned = TRUE;
 232 }
 233
 234 int
 235 main(argc, argv)
 236 int     argc;
 237 char *  argv[];
 238 {
 239         register int            i;
 240         register int            c;
 241         register int            vflag;
 242         register char *         cutarg;
 243         register long           cutloyear = ZDUMP_LO_YEAR;
 244         register long           cuthiyear = ZDUMP_HI_YEAR;
 245         register time_t         cutlotime;
 246         register time_t         cuthitime;
 247         register char **        fakeenv;
 248         time_t                  now;
 249         time_t                  t;
 250         time_t                  newt;
 251         struct tm               tm;
 252         struct tm               newtm;
 253         register struct tm *    tmp;
 254         register struct tm *    newtmp;
 255
 256         INITIALIZE(cutlotime);
 257         INITIALIZE(cuthitime);
 258 #if HAVE_GETTEXT
 259         (void) setlocale(LC_ALL, "");
 260 #ifdef TZ_DOMAINDIR
 261         (void) bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR);
 262 #endif /* defined TEXTDOMAINDIR */
 263         (void) textdomain(TZ_DOMAIN);
 264 #endif /* HAVE_GETTEXT */
 265         progname = argv[0];
 266         for (i = 1; i < argc; ++i)
 267                 if (strcmp(argv[i], "--version") == 0) {
 268                         (void) printf("%s\n", elsieid);
 269                         exit(EXIT_SUCCESS);
 270                 }
 271         vflag = 0;
 272         cutarg = NULL;
 273         while ((c = getopt(argc, argv, "c:v")) == 'c' || c == 'v')
 274                 if (c == 'v')
 275                         vflag = 1;
 276                 else    cutarg = optarg;
 277         if ((c != EOF && c != -1) ||
 278                 (optind == argc - 1 && strcmp(argv[optind], "=") == 0)) {
 279                         (void) fprintf(stderr,
 280 _("%s: usage is %s [ --version ] [ -v ] [ -c [loyear,]hiyear ] zonename ...\n"),
 281                                 progname, progname);
 282                         exit(EXIT_FAILURE);
 283         }
 284         if (vflag) {
 285                 if (cutarg != NULL) {
 286                         long    lo;
 287                         long    hi;
 288                         char    dummy;
 289
 290                         if (sscanf(cutarg, "%ld%c", &hi, &dummy) == 1) {
 291                                 cuthiyear = hi;
 292                         } else if (sscanf(cutarg, "%ld,%ld%c",
 293                                 &lo, &hi, &dummy) == 2) {
 294                                         cutloyear = lo;
 295                                         cuthiyear = hi;
 296                         } else {
 297 (void) fprintf(stderr, _("%s: wild -c argument %s\n"),
 298                                         progname, cutarg);
 299                                 exit(EXIT_FAILURE);
 300                         }
 301                 }
 302                 setabsolutes();
 303                 cutlotime = yeartot(cutloyear);
 304                 cuthitime = yeartot(cuthiyear);
 305         }
 306         (void) time(&now);
 307         longest = 0;
 308         for (i = optind; i < argc; ++i)
 309                 if (strlen(argv[i]) > longest)
 310                         longest = strlen(argv[i]);
 311         {
 312                 register int    from;
 313                 register int    to;
 314
 315                 for (i = 0; environ[i] != NULL; ++i)
 316                         continue;
 317                 fakeenv = (char **) malloc((size_t) ((i + 2) *
 318                         sizeof *fakeenv));
 319                 if (fakeenv == NULL ||
 320                         (fakeenv[0] = (char *) malloc(longest + 4)) == NULL) {
 321                                         (void) perror(progname);
 322                                         exit(EXIT_FAILURE);
 323                 }
 324                 to = 0;
 325                 (void) strcpy(fakeenv[to++], "TZ=");
 326                 for (from = 0; environ[from] != NULL; ++from)
 327                         if (strncmp(environ[from], "TZ=", 3) != 0)
 328                                 fakeenv[to++] = environ[from];
 329                 fakeenv[to] = NULL;
 330                 environ = fakeenv;
 331         }
 332         for (i = optind; i < argc; ++i) {
 333                 static char     buf[MAX_STRING_LENGTH];
 334
 335                 (void) strcpy(&fakeenv[0][3], argv[i]);
 336                 if (!vflag) {
 337                         show(argv[i], now, FALSE);
 338                         continue;
 339                 }
 340                 warned = FALSE;
 341                 t = absolute_min_time;
 342                 show(argv[i], t, TRUE);
 343                 t += SECSPERHOUR * HOURSPERDAY;
 344                 show(argv[i], t, TRUE);
 345                 if (t < cutlotime)
 346                         t = cutlotime;
 347                 tmp = my_localtime(&t);
 348                 if (tmp != NULL) {
 349                         tm = *tmp;
 350                         (void) strncpy(buf, abbr(&tm), (sizeof buf) - 1);
 351                 }
 352                 for ( ; ; ) {
 353                         if (t >= cuthitime)
 354                                 break;
 355                         newt = t + SECSPERHOUR * 12;
 356                         if (newt >= cuthitime)
 357                                 break;
 358                         if (newt <= t)
 359                                 break;
 360                         newtmp = localtime(&newt);
 361                         if (newtmp != NULL)
 362                                 newtm = *newtmp;
 363                         if ((tmp == NULL || newtmp == NULL) ? (tmp != newtmp) :
 364                                 (delta(&newtm, &tm) != (newt - t) ||
 365                                 newtm.tm_isdst != tm.tm_isdst ||
 366                                 strcmp(abbr(&newtm), buf) != 0)) {
 367                                         newt = hunt(argv[i], t, newt);
 368                                         newtmp = localtime(&newt);
 369                                         if (newtmp != NULL) {
 370                                                 newtm = *newtmp;
 371                                                 (void) strncpy(buf,
 372                                                         abbr(&newtm),
 373                                                         (sizeof buf) - 1);
 374                                         }
 375                         }
 376                         t = newt;
 377                         tm = newtm;
 378                         tmp = newtmp;
 379                 }
 380                 t = absolute_max_time;
 381                 t -= SECSPERHOUR * HOURSPERDAY;
 382                 show(argv[i], t, TRUE);
 383                 t += SECSPERHOUR * HOURSPERDAY;
 384                 show(argv[i], t, TRUE);
 385         }
 386         if (fflush(stdout) || ferror(stdout)) {
 387                 (void) fprintf(stderr, "%s: ", progname);
 388                 (void) perror(_("Error writing to standard output"));
 389                 exit(EXIT_FAILURE);
 390         }
 391         exit(EXIT_SUCCESS);
 392         /* If exit fails to exit... */
 393         return EXIT_FAILURE;
 394 }
 395
 396 static void
 397 setabsolutes()
 398 {
 399         if (0.5 == (time_t) 0.5) {
 400                 /*
 401                 ** time_t is floating.
 402                 */
 403                 if (sizeof (time_t) == sizeof (float)) {
 404                         absolute_min_time = (time_t) -FLT_MAX;
 405                         absolute_max_time = (time_t) FLT_MAX;
 406                 } else if (sizeof (time_t) == sizeof (double)) {
 407                         absolute_min_time = (time_t) -DBL_MAX;
 408                         absolute_max_time = (time_t) DBL_MAX;
 409                 } else {
 410                         (void) fprintf(stderr,
 411 _("%s: use of -v on system with floating time_t other than float or double\n"),
 412                                 progname);
 413                         exit(EXIT_FAILURE);
 414                 }
 415         } else if (0 > (time_t) -1) {
 416                 /*
 417                 ** time_t is signed.  Assume overflow wraps around.
 418                 */
 419                 time_t t = 0;
 420                 time_t t1 = 1;
 421
 422                 while (t < t1) {
 423                         t = t1;
 424                         t1 = 2 * t1 + 1;
 425                 }
 426
 427                 absolute_max_time = t;
 428                 t = -t;
 429                 absolute_min_time = t - 1;
 430                 if (t < absolute_min_time)
 431                         absolute_min_time = t;
 432         } else {
 433                 /*
 434                 ** time_t is unsigned.
 435                 */
 436                 absolute_min_time = 0;
 437                 absolute_max_time = absolute_min_time - 1;
 438         }
 439 }
 440
 441 static time_t
 442 yeartot(y)
 443 const long      y;
 444 {
 445         register long   myy;
 446         register long   seconds;
 447         register time_t t;
 448
 449         myy = EPOCH_YEAR;
 450         t = 0;
 451         while (myy != y) {
 452                 if (myy < y) {
 453                         seconds = isleap(myy) ? SECSPERLYEAR : SECSPERNYEAR;
 454                         ++myy;
 455                         if (t > absolute_max_time - seconds) {
 456                                 t = absolute_max_time;
 457                                 break;
 458                         }
 459                         t += seconds;
 460                 } else {
 461                         --myy;
 462                         seconds = isleap(myy) ? SECSPERLYEAR : SECSPERNYEAR;
 463                         if (t < absolute_min_time + seconds) {
 464                                 t = absolute_min_time;
 465                                 break;
 466                         }
 467                         t -= seconds;
 468                 }
 469         }
 470         return t;
 471 }
 472
 473 static time_t
 474 hunt(char *name, time_t lot, time_t hit)
 475 {
 476         time_t                  t;
 477         long                    diff;
 478         struct tm               lotm;
 479         register struct tm *    lotmp;
 480         struct tm               tm;
 481         register struct tm *    tmp;
 482         char                    loab[MAX_STRING_LENGTH];
 483
 484         lotmp = my_localtime(&lot);
 485         if (lotmp != NULL) {
 486                 lotm = *lotmp;
 487                 (void) strncpy(loab, abbr(&lotm), (sizeof loab) - 1);
 488         }
 489         for ( ; ; ) {
 490                 diff = (long) (hit - lot);
 491                 if (diff < 2)
 492                         break;
 493                 t = lot;
 494                 t += diff / 2;
 495                 if (t <= lot)
 496                         ++t;
 497                 else if (t >= hit)
 498                         --t;
 499                 tmp = my_localtime(&t);
 500                 if (tmp != NULL)
 501                         tm = *tmp;
 502                 if ((lotmp == NULL || tmp == NULL) ? (lotmp == tmp) :
 503                         (delta(&tm, &lotm) == (t - lot) &&
 504                         tm.tm_isdst == lotm.tm_isdst &&
 505                         strcmp(abbr(&tm), loab) == 0)) {
 506                                 lot = t;
 507                                 lotm = tm;
 508                                 lotmp = tmp;
 509                 } else  hit = t;
 510         }
 511         show(name, lot, TRUE);
 512         show(name, hit, TRUE);
 513         return hit;
 514 }
 515
 516 /*
 517 ** Thanks to Paul Eggert for logic used in delta.
 518 */
 519
 520 static long
 521 delta(newp, oldp)
 522 struct tm *     newp;
 523 struct tm *     oldp;
 524 {
 525         register long   result;
 526         register int    tmy;
 527
 528         if (newp->tm_year < oldp->tm_year)
 529                 return -delta(oldp, newp);
 530         result = 0;
 531         for (tmy = oldp->tm_year; tmy < newp->tm_year; ++tmy)
 532                 result += DAYSPERNYEAR + isleap_sum(tmy, TM_YEAR_BASE);
 533         result += newp->tm_yday - oldp->tm_yday;
 534         result *= HOURSPERDAY;
 535         result += newp->tm_hour - oldp->tm_hour;
 536         result *= MINSPERHOUR;
 537         result += newp->tm_min - oldp->tm_min;
 538         result *= SECSPERMIN;
 539         result += newp->tm_sec - oldp->tm_sec;
 540         return result;
 541 }
 542
 543 static void
 544 show(char *zone, time_t t, int v)
 545 {
 546         register struct tm *    tmp;
 547
 548         (void) printf("%-*s  ", (int) longest, zone);
 549         if (v) {
 550                 tmp = gmtime(&t);
 551                 if (tmp == NULL) {
 552                         (void) printf(tformat(), t);
 553                 } else {
 554                         dumptime(tmp);
 555                         (void) printf(" UTC");
 556                 }
 557                 (void) printf(" = ");
 558         }
 559         tmp = my_localtime(&t);
 560         dumptime(tmp);
 561         if (tmp != NULL) {
 562                 if (*abbr(tmp) != '\0')
 563                         (void) printf(" %s", abbr(tmp));
 564                 if (v) {
 565                         (void) printf(" isdst=%d", tmp->tm_isdst);
 566 #ifdef TM_GMTOFF
 567                         (void) printf(" gmtoff=%ld", tmp->TM_GMTOFF);
 568 #endif /* defined TM_GMTOFF */
 569                 }
 570         }
 571         (void) printf("\n");
 572         if (tmp != NULL && *abbr(tmp) != '\0')
 573                 abbrok(abbr(tmp), zone);
 574 }
 575
 576 static char *
 577 abbr(tmp)
 578 struct tm *     tmp;
 579 {
 580         register char * result;
 581         static char     nada;
 582
 583         if (tmp->tm_isdst != 0 && tmp->tm_isdst != 1)
 584                 return &nada;
 585         result = tzname[tmp->tm_isdst];
 586         return (result == NULL) ? &nada : result;
 587 }
 588
 589 /*
 590 ** The code below can fail on certain theoretical systems;
 591 ** it works on all known real-world systems as of 2004-12-30.
 592 */
 593
 594 static const char *
 595 tformat()
 596 {
 597         if (0.5 == (time_t) 0.5) {      /* floating */
 598                 if (sizeof (time_t) > sizeof (double))
 599                         return "%Lg";
 600                 return "%g";
 601         }
 602         if (0 > (time_t) -1) {          /* signed */
 603                 if (sizeof (time_t) > sizeof (long))
 604                         return "%lld";
 605                 if (sizeof (time_t) > sizeof (int))
 606                         return "%ld";
 607                 return "%d";
 608         }
 609         if (sizeof (time_t) > sizeof (unsigned long))
 610                 return "%llu";
 611         if (sizeof (time_t) > sizeof (unsigned int))
 612                 return "%lu";
 613         return "%u";
 614 }
 615
 616 static void
 617 dumptime(timeptr)
 618 register const struct tm *      timeptr;
 619 {
 620         static const char       wday_name[][3] = {
 621                 "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
 622         };
 623         static const char       mon_name[][3] = {
 624                 "Jan", "Feb", "Mar", "Apr", "May", "Jun",
 625                 "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
 626         };
 627         register const char *   wn;
 628         register const char *   mn;
 629         register int            lead;
 630         register int            trail;
 631
 632         if (timeptr == NULL) {
 633                 (void) printf("NULL");
 634                 return;
 635         }
 636         /*
 637         ** The packaged versions of localtime and gmtime never put out-of-range
 638         ** values in tm_wday or tm_mon, but since this code might be compiled
 639         ** with other (perhaps experimental) versions, paranoia is in order.
 640         */
 641         if (timeptr->tm_wday < 0 || timeptr->tm_wday >=
 642                 (int) (sizeof wday_name / sizeof wday_name[0]))
 643                         wn = "???";
 644         else            wn = wday_name[timeptr->tm_wday];
 645         if (timeptr->tm_mon < 0 || timeptr->tm_mon >=
 646                 (int) (sizeof mon_name / sizeof mon_name[0]))
 647                         mn = "???";
 648         else            mn = mon_name[timeptr->tm_mon];
 649         (void) printf("%.3s %.3s%3d %.2d:%.2d:%.2d ",
 650                 wn, mn,
 651                 timeptr->tm_mday, timeptr->tm_hour,
 652                 timeptr->tm_min, timeptr->tm_sec);
 653 #define DIVISOR 10
 654         trail = timeptr->tm_year % DIVISOR + TM_YEAR_BASE % DIVISOR;
 655         lead = timeptr->tm_year / DIVISOR + TM_YEAR_BASE / DIVISOR +
 656                 trail / DIVISOR;
 657         trail %= DIVISOR;
 658         if (trail < 0 && lead > 0) {
 659                 trail += DIVISOR;
 660                 --lead;
 661         } else if (lead < 0 && trail > 0) {
 662                 trail -= DIVISOR;
 663                 ++lead;
 664         }
 665         if (lead == 0)
 666                 (void) printf("%d", trail);
 667         else    (void) printf("%d%d", lead, ((trail < 0) ? -trail : trail));
 668 }