contrib/tzcode/zic/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 #ifndef lint
   7 static const char rcsid[] =
   8   "$FreeBSD$";
   9 static char     elsieid[] = "@(#)zdump.c        8.10";
  10 #endif /* not lint */
  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 #include <float.h>      /* for FLT_MAX and DBL_MAX */
  26 #include <ctype.h>      /* for isalpha et al. */
  27 #ifndef isascii
  28 #define isascii(x) 1
  29 #endif /* !defined isascii */
  30
  31 #ifndef ZDUMP_LO_YEAR
  32 #define ZDUMP_LO_YEAR   (-500)
  33 #endif /* !defined ZDUMP_LO_YEAR */
  34
  35 #ifndef ZDUMP_HI_YEAR
  36 #define ZDUMP_HI_YEAR   2500
  37 #endif /* !defined ZDUMP_HI_YEAR */
  38
  39 #ifndef MAX_STRING_LENGTH
  40 #define MAX_STRING_LENGTH       1024
  41 #endif /* !defined MAX_STRING_LENGTH */
  42
  43 #ifndef TRUE
  44 #define TRUE            1
  45 #endif /* !defined TRUE */
  46
  47 #ifndef FALSE
  48 #define FALSE           0
  49 #endif /* !defined FALSE */
  50
  51 #ifndef EXIT_SUCCESS
  52 #define EXIT_SUCCESS    0
  53 #endif /* !defined EXIT_SUCCESS */
  54
  55 #ifndef EXIT_FAILURE
  56 #define EXIT_FAILURE    1
  57 #endif /* !defined EXIT_FAILURE */
  58
  59 #ifndef SECSPERMIN
  60 #define SECSPERMIN      60
  61 #endif /* !defined SECSPERMIN */
  62
  63 #ifndef MINSPERHOUR
  64 #define MINSPERHOUR     60
  65 #endif /* !defined MINSPERHOUR */
  66
  67 #ifndef SECSPERHOUR
  68 #define SECSPERHOUR     (SECSPERMIN * MINSPERHOUR)
  69 #endif /* !defined SECSPERHOUR */
  70
  71 #ifndef HOURSPERDAY
  72 #define HOURSPERDAY     24
  73 #endif /* !defined HOURSPERDAY */
  74
  75 #ifndef EPOCH_YEAR
  76 #define EPOCH_YEAR      1970
  77 #endif /* !defined EPOCH_YEAR */
  78
  79 #ifndef TM_YEAR_BASE
  80 #define TM_YEAR_BASE    1900
  81 #endif /* !defined TM_YEAR_BASE */
  82
  83 #ifndef DAYSPERNYEAR
  84 #define DAYSPERNYEAR    365
  85 #endif /* !defined DAYSPERNYEAR */
  86
  87 #ifndef isleap
  88 #define isleap(y) (((y) % 4) == 0 && (((y) % 100) != 0 || ((y) % 400) == 0))
  89 #endif /* !defined isleap */
  90
  91 #ifndef isleap_sum
  92 /*
  93 ** See tzfile.h for details on isleap_sum.
  94 */
  95 #define isleap_sum(a, b)        isleap((a) % 400 + (b) % 400)
  96 #endif /* !defined isleap_sum */
  97
  98 #define SECSPERDAY      ((long) SECSPERHOUR * HOURSPERDAY)
  99 #define SECSPERNYEAR    (SECSPERDAY * DAYSPERNYEAR)
 100 #define SECSPERLYEAR    (SECSPERNYEAR + SECSPERDAY)
 101
 102 #ifndef HAVE_GETTEXT
 103 #define HAVE_GETTEXT 0
 104 #endif
 105 #if HAVE_GETTEXT
 106 #include "locale.h"     /* for setlocale */
 107 #include "libintl.h"
 108 #endif /* HAVE_GETTEXT */
 109
 110 #ifndef GNUC_or_lint
 111 #ifdef lint
 112 #define GNUC_or_lint
 113 #else /* !defined lint */
 114 #ifdef __GNUC__
 115 #define GNUC_or_lint
 116 #endif /* defined __GNUC__ */
 117 #endif /* !defined lint */
 118 #endif /* !defined GNUC_or_lint */
 119
 120 #ifndef INITIALIZE
 121 #ifdef GNUC_or_lint
 122 #define INITIALIZE(x)   ((x) = 0)
 123 #else /* !defined GNUC_or_lint */
 124 #define INITIALIZE(x)
 125 #endif /* !defined GNUC_or_lint */
 126 #endif /* !defined INITIALIZE */
 127
 128 /*
 129 ** For the benefit of GNU folk...
 130 ** `_(MSGID)' uses the current locale's message library string for MSGID.
 131 ** The default is to use gettext if available, and use MSGID otherwise.
 132 */
 133
 134 #ifndef _
 135 #if HAVE_GETTEXT
 136 #define _(msgid) gettext(msgid)
 137 #else /* !(HAVE_GETTEXT) */
 138 #define _(msgid) msgid
 139 #endif /* !(HAVE_GETTEXT) */
 140 #endif /* !defined _ */
 141
 142 #ifndef TZ_DOMAIN
 143 #define TZ_DOMAIN "tz"
 144 #endif /* !defined TZ_DOMAIN */
 145
 146 extern char **  environ;
 147 extern char *   tzname[2];
 148
 149 static time_t   absolute_min_time;
 150 static time_t   absolute_max_time;
 151 static size_t   longest;
 152 static char *   progname;
 153 static int      warned;
 154
 155 static void     usage(FILE *stream, int status);
 156 static char *   abbr(struct tm * tmp);
 157 static void     abbrok(const char * abbrp, const char * zone);
 158 static long     delta(struct tm * newp, struct tm * oldp);
 159 static void     dumptime(const struct tm * tmp);
 160 static time_t   hunt(char * name, time_t lot, time_t    hit);
 161 static void     setabsolutes(void);
 162 static void     show(char * zone, time_t t, int v);
 163 static const char *     tformat(void);
 164 static time_t   yeartot(long y);
 165
 166 #ifndef TYPECHECK
 167 #define my_localtime    localtime
 168 #else /* !defined TYPECHECK */
 169 static struct tm *
 170 my_localtime(tp)
 171 time_t *        tp;
 172 {
 173         register struct tm *    tmp;
 174
 175         tmp = localtime(tp);
 176         if (tp != NULL && tmp != NULL) {
 177                 struct tm       tm;
 178                 register time_t t;
 179
 180                 tm = *tmp;
 181                 t = mktime(&tm);
 182                 if (t - *tp >= 1 || *tp - t >= 1) {
 183                         (void) fflush(stdout);
 184                         (void) fprintf(stderr, "\n%s: ", progname);
 185                         (void) fprintf(stderr, tformat(), *tp);
 186                         (void) fprintf(stderr, " ->");
 187                         (void) fprintf(stderr, " year=%d", tmp->tm_year);
 188                         (void) fprintf(stderr, " mon=%d", tmp->tm_mon);
 189                         (void) fprintf(stderr, " mday=%d", tmp->tm_mday);
 190                         (void) fprintf(stderr, " hour=%d", tmp->tm_hour);
 191                         (void) fprintf(stderr, " min=%d", tmp->tm_min);
 192                         (void) fprintf(stderr, " sec=%d", tmp->tm_sec);
 193                         (void) fprintf(stderr, " isdst=%d", tmp->tm_isdst);
 194                         (void) fprintf(stderr, " -> ");
 195                         (void) fprintf(stderr, tformat(), t);
 196                         (void) fprintf(stderr, "\n");
 197                 }
 198         }
 199         return tmp;
 200 }
 201 #endif /* !defined TYPECHECK */
 202
 203 static void
 204 abbrok(abbrp, zone)
 205 const char * const      abbrp;
 206 const char * const      zone;
 207 {
 208         register const char *   cp;
 209         register char *         wp;
 210
 211         if (warned)
 212                 return;
 213         cp = abbrp;
 214         wp = NULL;
 215         while (isascii((unsigned char) *cp) && isalpha((unsigned char) *cp))
 216                 ++cp;
 217         if (cp - abbrp == 0)
 218                 wp = _("lacks alphabetic at start");
 219         else if (cp - abbrp < 3)
 220                 wp = _("has fewer than 3 alphabetics");
 221         else if (cp - abbrp > 6)
 222                 wp = _("has more than 6 alphabetics");
 223         if (wp == NULL && (*cp == '+' || *cp == '-')) {
 224                 ++cp;
 225                 if (isascii((unsigned char) *cp) &&
 226                         isdigit((unsigned char) *cp))
 227                                 if (*cp++ == '1' && *cp >= '0' && *cp <= '4')
 228                                         ++cp;
 229                 if (*cp != '\0')
 230                         wp = _("differs from POSIX standard");
 231         }
 232         if (wp == NULL)
 233                 return;
 234         (void) fflush(stdout);
 235         (void) fprintf(stderr,
 236                 _("%s: warning: zone \"%s\" abbreviation \"%s\" %s\n"),
 237                 progname, zone, abbrp, wp);
 238         warned = TRUE;
 239 }
 240
 241 int
 242 main(argc, argv)
 243 int     argc;
 244 char *  argv[];
 245 {
 246         register int            i;
 247         register int            c;
 248         register int            vflag;
 249         register char *         cutarg;
 250         register long           cutloyear = ZDUMP_LO_YEAR;
 251         register long           cuthiyear = ZDUMP_HI_YEAR;
 252         register time_t         cutlotime;
 253         register time_t         cuthitime;
 254         register char **        fakeenv;
 255         time_t                  now;
 256         time_t                  t;
 257         time_t                  newt;
 258         struct tm               tm;
 259         struct tm               newtm;
 260         register struct tm *    tmp;
 261         register struct tm *    newtmp;
 262
 263         progname=argv[0];
 264         INITIALIZE(cutlotime);
 265         INITIALIZE(cuthitime);
 266 #if HAVE_GETTEXT
 267         (void) setlocale(LC_MESSAGES, "");
 268 #ifdef TZ_DOMAINDIR
 269         (void) bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR);
 270 #endif /* TEXTDOMAINDIR */
 271         (void) textdomain(TZ_DOMAIN);
 272 #endif /* HAVE_GETTEXT */
 273         for (i = 1; i < argc; ++i)
 274                 if (strcmp(argv[i], "--version") == 0) {
 275                         errx(EXIT_SUCCESS, "%s", elsieid);
 276                 } else if (strcmp(argv[i], "--help") == 0) {
 277                         usage(stdout, EXIT_SUCCESS);
 278                 }
 279         vflag = 0;
 280         cutarg = NULL;
 281         while ((c = getopt(argc, argv, "c:v")) == 'c' || c == 'v')
 282                 if (c == 'v')
 283                         vflag = 1;
 284                 else    cutarg = optarg;
 285         if ((c != -1) ||
 286                 (optind == argc - 1 && strcmp(argv[optind], "=") == 0)) {
 287                         usage(stderr, EXIT_FAILURE);
 288         }
 289         if (vflag) {
 290                 if (cutarg != NULL) {
 291                         long    lo;
 292                         long    hi;
 293                         char    dummy;
 294
 295                         if (sscanf(cutarg, "%ld%c", &hi, &dummy) == 1) {
 296                                 cuthiyear = hi;
 297                         } else if (sscanf(cutarg, "%ld,%ld%c",
 298                                 &lo, &hi, &dummy) == 2) {
 299                                         cutloyear = lo;
 300                                         cuthiyear = hi;
 301                         } else {
 302 (void) fprintf(stderr, _("%s: wild -c argument %s\n"),
 303                                         progname, cutarg);
 304                                 exit(EXIT_FAILURE);
 305                         }
 306                 }
 307                 setabsolutes();
 308                 cutlotime = yeartot(cutloyear);
 309                 cuthitime = yeartot(cuthiyear);
 310         }
 311         (void) time(&now);
 312         longest = 0;
 313         for (i = optind; i < argc; ++i)
 314                 if (strlen(argv[i]) > longest)
 315                         longest = strlen(argv[i]);
 316         {
 317                 register int    from;
 318                 register int    to;
 319
 320                 for (i = 0;  environ[i] != NULL; ++i)
 321                         continue;
 322                 fakeenv = (char **) malloc((size_t) ((i + 2) *
 323                         sizeof *fakeenv));
 324                 if (fakeenv == NULL ||
 325                         (fakeenv[0] = (char *) malloc((size_t) (longest +
 326                                 4))) == NULL)
 327                                         errx(EXIT_FAILURE,
 328                                              _("malloc() failed"));
 329                 to = 0;
 330                 (void) strcpy(fakeenv[to++], "TZ=");
 331                 for (from = 0; environ[from] != NULL; ++from)
 332                         if (strncmp(environ[from], "TZ=", 3) != 0)
 333                                 fakeenv[to++] = environ[from];
 334                 fakeenv[to] = NULL;
 335                 environ = fakeenv;
 336         }
 337         for (i = optind; i < argc; ++i) {
 338                 static char     buf[MAX_STRING_LENGTH];
 339
 340                 (void) strcpy(&fakeenv[0][3], argv[i]);
 341                 if (!vflag) {
 342                         show(argv[i], now, FALSE);
 343                         continue;
 344                 }
 345                 warned = FALSE;
 346                 t = absolute_min_time;
 347                 show(argv[i], t, TRUE);
 348                 t += SECSPERHOUR * HOURSPERDAY;
 349                 show(argv[i], t, TRUE);
 350                 if (t < cutlotime)
 351                         t = cutlotime;
 352                 tmp = my_localtime(&t);
 353                 if (tmp != NULL) {
 354                         tm = *tmp;
 355                         (void) strncpy(buf, abbr(&tm), (sizeof buf) - 1);
 356                 }
 357                 for ( ; ; ) {
 358                         if (t >= cuthitime || t >= cuthitime - SECSPERHOUR * 12)
 359                                 break;
 360                         newt = t + SECSPERHOUR * 12;
 361                         newtmp = localtime(&newt);
 362                         if (newtmp != NULL)
 363                                 newtm = *newtmp;
 364                         if ((tmp == NULL || newtmp == NULL) ? (tmp != newtmp) :
 365                                 (delta(&newtm, &tm) != (newt - t) ||
 366                                 newtm.tm_isdst != tm.tm_isdst ||
 367                                 strcmp(abbr(&newtm), buf) != 0)) {
 368                                         newt = hunt(argv[i], t, newt);
 369                                         newtmp = localtime(&newt);
 370                                         if (newtmp != NULL) {
 371                                                 newtm = *newtmp;
 372                                                 (void) strncpy(buf,
 373                                                         abbr(&newtm),
 374                                                         (sizeof buf) - 1);
 375                                         }
 376                         }
 377                         t = newt;
 378                         tm = newtm;
 379                         tmp = newtmp;
 380                 }
 381                 t = absolute_max_time;
 382                 t -= SECSPERHOUR * HOURSPERDAY;
 383                 show(argv[i], t, TRUE);
 384                 t += SECSPERHOUR * HOURSPERDAY;
 385                 show(argv[i], t, TRUE);
 386         }
 387         if (fflush(stdout) || ferror(stdout))
 388                 errx(EXIT_FAILURE, _("error writing standard output"));
 389         exit(EXIT_SUCCESS);
 390         /* If exit fails to exit... */
 391         return(EXIT_FAILURE);
 392 }
 393
 394 static void
 395 setabsolutes(void)
 396 {
 397         if (0.5 == (time_t) 0.5) {
 398                 /*
 399                 ** time_t is floating.
 400                 */
 401                 if (sizeof (time_t) == sizeof (float)) {
 402                         absolute_min_time = (time_t) -FLT_MAX;
 403                         absolute_max_time = (time_t) FLT_MAX;
 404                 } else if (sizeof (time_t) == sizeof (double)) {
 405                         absolute_min_time = (time_t) -DBL_MAX;
 406                         absolute_max_time = (time_t) DBL_MAX;
 407                 } else {
 408                         (void) fprintf(stderr,
 409 _("%s: use of -v on system with floating time_t other than float or double\n"),
 410                                 progname);
 411                         exit(EXIT_FAILURE);
 412                 }
 413         } else if (0 > (time_t) -1) {
 414                 /*
 415                 ** time_t is signed.  Assume overflow wraps around.
 416                 */
 417                 time_t t = 0;
 418                 time_t t1 = 1;
 419
 420                 while (t < t1) {
 421                         t = t1;
 422                         t1 = 2 * t1 + 1;
 423                 }
 424
 425                 absolute_max_time = t;
 426                 t = -t;
 427                 absolute_min_time = t - 1;
 428                 if (t < absolute_min_time)
 429                         absolute_min_time = t;
 430         } else {
 431                 /*
 432                 ** time_t is unsigned.
 433                 */
 434                 absolute_min_time = 0;
 435                 absolute_max_time = absolute_min_time - 1;
 436         }
 437 }
 438
 439 static time_t
 440 yeartot(y)
 441 const long      y;
 442 {
 443         register long   myy;
 444         register long   seconds;
 445         register time_t t;
 446
 447         myy = EPOCH_YEAR;
 448         t = 0;
 449         while (myy != y) {
 450                 if (myy < y) {
 451                         seconds = isleap(myy) ? SECSPERLYEAR : SECSPERNYEAR;
 452                         ++myy;
 453                         if (t > absolute_max_time - seconds) {
 454                                 t = absolute_max_time;
 455                                 break;
 456                         }
 457                         t += seconds;
 458                 } else {
 459                         --myy;
 460                         seconds = isleap(myy) ? SECSPERLYEAR : SECSPERNYEAR;
 461                         if (t < absolute_min_time + seconds) {
 462                                 t = absolute_min_time;
 463                                 break;
 464                         }
 465                         t -= seconds;
 466                 }
 467         }
 468         return t;
 469 }
 470
 471 static void
 472 usage(FILE *stream, int status)
 473 {
 474         fprintf(stream,
 475 _("usage: %s [--version] [-v] [--help] [-c [loyear,]hiyear] zonename ...\n\
 476 \n\
 477 Report bugs to tz@elsie.nci.nih.gov.\n"), progname);
 478         exit(status);
 479 }
 480
 481 static time_t
 482 hunt(char *name, time_t lot, time_t hit)
 483 {
 484         time_t                  t;
 485         long                    diff;
 486         struct tm               lotm;
 487         register struct tm *    lotmp;
 488         struct tm               tm;
 489         register struct tm *    tmp;
 490         char                    loab[MAX_STRING_LENGTH];
 491
 492         lotmp = my_localtime(&lot);
 493         if (lotmp != NULL) {
 494                 lotm = *lotmp;
 495                 (void) strncpy(loab, abbr(&lotm), (sizeof loab) - 1);
 496         }
 497         for ( ; ; ) {
 498                 diff = (long) (hit - lot);
 499                 if (diff < 2)
 500                         break;
 501                 t = lot;
 502                 t += diff / 2;
 503                 if (t <= lot)
 504                         ++t;
 505                 else if (t >= hit)
 506                         --t;
 507                 tmp = my_localtime(&t);
 508                 if (tmp != NULL)
 509                         tm = *tmp;
 510                 if ((lotmp == NULL || tmp == NULL) ? (lotmp == tmp) :
 511                         (delta(&tm, &lotm) == (t - lot) &&
 512                         tm.tm_isdst == lotm.tm_isdst &&
 513                         strcmp(abbr(&tm), loab) == 0)) {
 514                                 lot = t;
 515                                 lotm = tm;
 516                                 lotmp = tmp;
 517                 } else  hit = t;
 518         }
 519         show(name, lot, TRUE);
 520         show(name, hit, TRUE);
 521         return hit;
 522 }
 523
 524 /*
 525 ** Thanks to Paul Eggert for logic used in delta.
 526 */
 527
 528 static long
 529 delta(newp, oldp)
 530 struct tm *     newp;
 531 struct tm *     oldp;
 532 {
 533         register long   result;
 534         register int    tmy;
 535
 536         if (newp->tm_year < oldp->tm_year)
 537                 return -delta(oldp, newp);
 538         result = 0;
 539         for (tmy = oldp->tm_year; tmy < newp->tm_year; ++tmy)
 540                 result += DAYSPERNYEAR + isleap_sum(tmy, TM_YEAR_BASE);
 541         result += newp->tm_yday - oldp->tm_yday;
 542         result *= HOURSPERDAY;
 543         result += newp->tm_hour - oldp->tm_hour;
 544         result *= MINSPERHOUR;
 545         result += newp->tm_min - oldp->tm_min;
 546         result *= SECSPERMIN;
 547         result += newp->tm_sec - oldp->tm_sec;
 548         return result;
 549 }
 550
 551 static void
 552 show(char *zone, time_t t, int v)
 553 {
 554         register struct tm *    tmp;
 555
 556         (void) printf("%-*s  ", (int) longest, zone);
 557         if (v) {
 558                 tmp = gmtime(&t);
 559                 if (tmp == NULL) {
 560                         (void) printf(tformat(), t);
 561                 } else {
 562                         dumptime(tmp);
 563                         (void) printf(" UTC");
 564                 }
 565                 (void) printf(" = ");
 566         }
 567         tmp = my_localtime(&t);
 568         dumptime(tmp);
 569         if (tmp != NULL) {
 570                 if (*abbr(tmp) != '\0')
 571                         (void) printf(" %s", abbr(tmp));
 572                 if (v) {
 573                         (void) printf(" isdst=%d", tmp->tm_isdst);
 574 #ifdef TM_GMTOFF
 575                         (void) printf(" gmtoff=%ld", tmp->TM_GMTOFF);
 576 #endif /* defined TM_GMTOFF */
 577                 }
 578         }
 579         (void) printf("\n");
 580         if (tmp != NULL && *abbr(tmp) != '\0')
 581                 abbrok(abbr(tmp), zone);
 582 }
 583
 584 static char *
 585 abbr(tmp)
 586 struct tm *     tmp;
 587 {
 588         register char * result;
 589         static char     nada;
 590
 591         if (tmp->tm_isdst != 0 && tmp->tm_isdst != 1)
 592                 return &nada;
 593         result = tzname[tmp->tm_isdst];
 594         return (result == NULL) ? &nada : result;
 595 }
 596
 597 /*
 598 ** The code below can fail on certain theoretical systems;
 599 ** it works on all known real-world systems as of 2004-12-30.
 600 */
 601
 602 static const char *
 603 tformat(void)
 604 {
 605         if (0.5 == (time_t) 0.5) {      /* floating */
 606                 if (sizeof (time_t) > sizeof (double))
 607                         return "%Lg";
 608                 return "%g";
 609         }
 610         if (0 > (time_t) -1) {          /* signed */
 611                 if (sizeof (time_t) > sizeof (long))
 612                         return "%lld";
 613                 if (sizeof (time_t) > sizeof (int))
 614                         return "%ld";
 615                 return "%d";
 616         }
 617         if (sizeof (time_t) > sizeof (unsigned long))
 618                 return "%llu";
 619         if (sizeof (time_t) > sizeof (unsigned int))
 620                 return "%lu";
 621         return "%u";
 622 }
 623
 624 static void
 625 dumptime(timeptr)
 626 register const struct tm *      timeptr;
 627 {
 628         static const char       wday_name[][3] = {
 629                 "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
 630         };
 631         static const char       mon_name[][3] = {
 632                 "Jan", "Feb", "Mar", "Apr", "May", "Jun",
 633                 "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
 634         };
 635         register const char *   wn;
 636         register const char *   mn;
 637         register int            lead;
 638         register int            trail;
 639
 640         if (timeptr == NULL) {
 641                 (void) printf("NULL");
 642                 return;
 643         }
 644         /*
 645         ** The packaged versions of localtime and gmtime never put out-of-range
 646         ** values in tm_wday or tm_mon, but since this code might be compiled
 647         ** with other (perhaps experimental) versions, paranoia is in order.
 648         */
 649         if (timeptr->tm_wday < 0 || timeptr->tm_wday >=
 650                 (int) (sizeof wday_name / sizeof wday_name[0]))
 651                         wn = "???";
 652         else            wn = wday_name[timeptr->tm_wday];
 653         if (timeptr->tm_mon < 0 || timeptr->tm_mon >=
 654                 (int) (sizeof mon_name / sizeof mon_name[0]))
 655                         mn = "???";
 656         else            mn = mon_name[timeptr->tm_mon];
 657         (void) printf("%.3s %.3s%3d %.2d:%.2d:%.2d ",
 658                 wn, mn,
 659                 timeptr->tm_mday, timeptr->tm_hour,
 660                 timeptr->tm_min, timeptr->tm_sec);
 661 #define DIVISOR 10
 662         trail = timeptr->tm_year % DIVISOR + TM_YEAR_BASE % DIVISOR;
 663         lead = timeptr->tm_year / DIVISOR + TM_YEAR_BASE / DIVISOR +
 664                 trail / DIVISOR;
 665         trail %= DIVISOR;
 666         if (trail < 0 && lead > 0) {
 667                 trail += DIVISOR;
 668                 --lead;
 669         } else if (lead < 0 && trail > 0) {
 670                 trail -= DIVISOR;
 671                 ++lead;
 672         }
 673         if (lead == 0)
 674                 (void) printf("%d", trail);
 675         else    (void) printf("%d%d", lead, ((trail < 0) ? -trail : trail));
 676 }