summary refs log tree commit diff
path: root/timezone/zdump.c
blob: b532fe3eae47e5ece357266ee2b990af05371609 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
/* Dump time zone data in a textual format.  */

/*
** This file is in the public domain, so clarified as of
** 2009-05-17 by Arthur David Olson.
*/

#include "version.h"

#ifndef NETBSD_INSPIRED
# define NETBSD_INSPIRED 1
#endif

#include "private.h"
#include <stdio.h>

#ifndef HAVE_SNPRINTF
# define HAVE_SNPRINTF (199901 <= __STDC_VERSION__)
#endif

#ifndef HAVE_LOCALTIME_R
# define HAVE_LOCALTIME_R 1
#endif

#ifndef HAVE_LOCALTIME_RZ
# ifdef TM_ZONE
#  define HAVE_LOCALTIME_RZ (NETBSD_INSPIRED && USE_LTZ)
# else
#  define HAVE_LOCALTIME_RZ 0
# endif
#endif

#ifndef HAVE_TZSET
# define HAVE_TZSET 1
#endif

#ifndef ZDUMP_LO_YEAR
#define ZDUMP_LO_YEAR	(-500)
#endif /* !defined ZDUMP_LO_YEAR */

#ifndef ZDUMP_HI_YEAR
#define ZDUMP_HI_YEAR	2500
#endif /* !defined ZDUMP_HI_YEAR */

#ifndef MAX_STRING_LENGTH
#define MAX_STRING_LENGTH	1024
#endif /* !defined MAX_STRING_LENGTH */

#define SECSPERNYEAR	(SECSPERDAY * DAYSPERNYEAR)
#define SECSPERLYEAR	(SECSPERNYEAR + SECSPERDAY)
#define SECSPER400YEARS	(SECSPERNYEAR * (intmax_t) (300 + 3)	\
			 + SECSPERLYEAR * (intmax_t) (100 - 3))

/*
** True if SECSPER400YEARS is known to be representable as an
** intmax_t.  It's OK that SECSPER400YEARS_FITS can in theory be false
** even if SECSPER400YEARS is representable, because when that happens
** the code merely runs a bit more slowly, and this slowness doesn't
** occur on any practical platform.
*/
enum { SECSPER400YEARS_FITS = SECSPERLYEAR <= INTMAX_MAX / 400 };

#if HAVE_GETTEXT
#include <locale.h>	/* for setlocale */
#endif /* HAVE_GETTEXT */

#if ! HAVE_LOCALTIME_RZ
# undef  timezone_t
# define timezone_t char **
#endif

#if !HAVE_POSIX_DECLS
extern int	getopt(int argc, char * const argv[],
			const char * options);
extern char *	optarg;
extern int	optind;
#endif

/* The minimum and maximum finite time values.  */
enum { atime_shift = CHAR_BIT * sizeof (time_t) - 2 };
static time_t const absolute_min_time =
  ((time_t) -1 < 0
   ? (- ((time_t) ~ (time_t) 0 < 0)
      - (((time_t) 1 << atime_shift) - 1 + ((time_t) 1 << atime_shift)))
   : 0);
static time_t const absolute_max_time =
  ((time_t) -1 < 0
   ? (((time_t) 1 << atime_shift) - 1 + ((time_t) 1 << atime_shift))
   : -1);
static int	longest;
static char *	progname;
static bool	warned;
static bool	errout;

static char const *abbr(struct tm const *);
static intmax_t	delta(struct tm *, struct tm *) ATTRIBUTE_PURE;
static void dumptime(struct tm const *);
static time_t hunt(timezone_t, char *, time_t, time_t);
static void show(timezone_t, char *, time_t, bool);
static void showtrans(char const *, struct tm const *, time_t, char const *,
		      char const *);
static const char *tformat(void);
static time_t yeartot(intmax_t) ATTRIBUTE_PURE;

/* Unlike <ctype.h>'s isdigit, this also works if c < 0 | c > UCHAR_MAX. */
#define is_digit(c) ((unsigned)(c) - '0' <= 9)

/* Is A an alphabetic character in the C locale?  */
static bool
is_alpha(char a)
{
	switch (a) {
	  default:
		return false;
	  case 'A': case 'B': case 'C': case 'D': case 'E': case 'F': case 'G':
	  case 'H': case 'I': case 'J': case 'K': case 'L': case 'M': case 'N':
	  case 'O': case 'P': case 'Q': case 'R': case 'S': case 'T': case 'U':
	  case 'V': case 'W': case 'X': case 'Y': case 'Z':
	  case 'a': case 'b': case 'c': case 'd': case 'e': case 'f': case 'g':
	  case 'h': case 'i': case 'j': case 'k': case 'l': case 'm': case 'n':
	  case 'o': case 'p': case 'q': case 'r': case 's': case 't': case 'u':
	  case 'v': case 'w': case 'x': case 'y': case 'z':
		return true;
	}
}

/* Return A + B, exiting if the result would overflow.  */
static size_t
sumsize(size_t a, size_t b)
{
  size_t sum = a + b;
  if (sum < a) {
    fprintf(stderr, "%s: size overflow\n", progname);
    exit(EXIT_FAILURE);
  }
  return sum;
}

/* Return a pointer to a newly allocated buffer of size SIZE, exiting
   on failure.  SIZE should be nonzero.  */
static void * ATTRIBUTE_MALLOC
xmalloc(size_t size)
{
  void *p = malloc(size);
  if (!p) {
    perror(progname);
    exit(EXIT_FAILURE);
  }
  return p;
}

#if ! HAVE_TZSET
# undef tzset
# define tzset zdump_tzset
static void tzset(void) { }
#endif

/* Assume gmtime_r works if localtime_r does.
   A replacement localtime_r is defined below if needed.  */
#if ! HAVE_LOCALTIME_R

# undef gmtime_r
# define gmtime_r zdump_gmtime_r

static struct tm *
gmtime_r(time_t *tp, struct tm *tmp)
{
  struct tm *r = gmtime(tp);
  if (r) {
    *tmp = *r;
    r = tmp;
  }
  return r;
}

#endif

/* Platforms with TM_ZONE don't need tzname, so they can use the
   faster localtime_rz or localtime_r if available.  */

#if defined TM_ZONE && HAVE_LOCALTIME_RZ
# define USE_LOCALTIME_RZ true
#else
# define USE_LOCALTIME_RZ false
#endif

#if ! USE_LOCALTIME_RZ

# if !defined TM_ZONE || ! HAVE_LOCALTIME_R || ! HAVE_TZSET
#  undef localtime_r
#  define localtime_r zdump_localtime_r
static struct tm *
localtime_r(time_t *tp, struct tm *tmp)
{
  struct tm *r = localtime(tp);
  if (r) {
    *tmp = *r;
    r = tmp;
  }
  return r;
}
# endif

# undef localtime_rz
# define localtime_rz zdump_localtime_rz
static struct tm *
localtime_rz(timezone_t rz, time_t *tp, struct tm *tmp)
{
  return localtime_r(tp, tmp);
}

# ifdef TYPECHECK
#  undef mktime_z
#  define mktime_z zdump_mktime_z
static time_t
mktime_z(timezone_t tz, struct tm *tmp)
{
  return mktime(tmp);
}
# endif

# undef tzalloc
# undef tzfree
# define tzalloc zdump_tzalloc
# define tzfree zdump_tzfree

static timezone_t
tzalloc(char const *val)
{
  static char **fakeenv;
  char **env = fakeenv;
  char *env0;
  if (! env) {
    char **e = environ;
    int to;

    while (*e++)
      continue;
    env = xmalloc(sumsize(sizeof *environ,
			  (e - environ) * sizeof *environ));
    to = 1;
    for (e = environ; (env[to] = *e); e++)
      to += strncmp(*e, "TZ=", 3) != 0;
  }
  env0 = xmalloc(sumsize(sizeof "TZ=", strlen(val)));
  env[0] = strcat(strcpy(env0, "TZ="), val);
  environ = fakeenv = env;
  tzset();
  return env;
}

static void
tzfree(timezone_t env)
{
  environ = env + 1;
  free(env[0]);
}
#endif /* ! USE_LOCALTIME_RZ */

/* A UT time zone, and its initializer.  */
static timezone_t gmtz;
static void
gmtzinit(void)
{
  if (USE_LOCALTIME_RZ) {
    static char const utc[] = "UTC0";
    gmtz = tzalloc(utc);
    if (!gmtz) {
      perror(utc);
      exit(EXIT_FAILURE);
    }
  }
}

/* Convert *TP to UT, storing the broken-down time into *TMP.
   Return TMP if successful, NULL otherwise.  This is like gmtime_r(TP, TMP),
   except typically faster if USE_LOCALTIME_RZ.  */
static struct tm *
my_gmtime_r(time_t *tp, struct tm *tmp)
{
  return USE_LOCALTIME_RZ ? localtime_rz(gmtz, tp, tmp) : gmtime_r(tp, tmp);
}

#ifndef TYPECHECK
# define my_localtime_rz localtime_rz
#else /* !defined TYPECHECK */

static struct tm *
my_localtime_rz(timezone_t tz, time_t *tp, struct tm *tmp)
{
	tmp = localtime_rz(tz, tp, tmp);
	if (tmp) {
		struct tm	tm;
		register time_t	t;

		tm = *tmp;
		t = mktime_z(tz, &tm);
		if (t != *tp) {
			fflush(stdout);
			fprintf(stderr, "\n%s: ", progname);
			fprintf(stderr, tformat(), *tp);
			fprintf(stderr, " ->");
			fprintf(stderr, " year=%d", tmp->tm_year);
			fprintf(stderr, " mon=%d", tmp->tm_mon);
			fprintf(stderr, " mday=%d", tmp->tm_mday);
			fprintf(stderr, " hour=%d", tmp->tm_hour);
			fprintf(stderr, " min=%d", tmp->tm_min);
			fprintf(stderr, " sec=%d", tmp->tm_sec);
			fprintf(stderr, " isdst=%d", tmp->tm_isdst);
			fprintf(stderr, " -> ");
			fprintf(stderr, tformat(), t);
			fprintf(stderr, "\n");
			errout = true;
		}
	}
	return tmp;
}
#endif /* !defined TYPECHECK */

static void
abbrok(const char *const abbrp, const char *const zone)
{
	register const char *	cp;
	register const char *	wp;

	if (warned)
		return;
	cp = abbrp;
	while (is_alpha(*cp) || is_digit(*cp) || *cp == '-' || *cp == '+')
		++cp;
	if (*cp)
	  wp = _("has characters other than ASCII alphanumerics, '-' or '+'");
	else if (cp - abbrp < 3)
	  wp = _("has fewer than 3 characters");
	else if (cp - abbrp > 6)
	  wp = _("has more than 6 characters");
	else
	  return;
	fflush(stdout);
	fprintf(stderr,
		_("%s: warning: zone \"%s\" abbreviation \"%s\" %s\n"),
		progname, zone, abbrp, wp);
	warned = errout = true;
}

/* Return a time zone abbreviation.  If the abbreviation needs to be
   saved, use *BUF (of size *BUFALLOC) to save it, and return the
   abbreviation in the possibly-reallocated *BUF.  Otherwise, just
   return the abbreviation.  Get the abbreviation from TMP.
   Exit on memory allocation failure.  */
static char const *
saveabbr(char **buf, size_t *bufalloc, struct tm const *tmp)
{
  char const *ab = abbr(tmp);
  if (HAVE_LOCALTIME_RZ)
    return ab;
  else {
    size_t ablen = strlen(ab);
    if (*bufalloc <= ablen) {
      free(*buf);

      /* Make the new buffer at least twice as long as the old,
	 to avoid O(N**2) behavior on repeated calls.  */
      *bufalloc = sumsize(*bufalloc, ablen + 1);

      *buf = xmalloc(*bufalloc);
    }
    return strcpy(*buf, ab);
  }
}

static void
close_file(FILE *stream)
{
  char const *e = (ferror(stream) ? _("I/O error")
		   : fclose(stream) != 0 ? strerror(errno) : NULL);
  if (e) {
    fprintf(stderr, "%s: %s\n", progname, e);
    exit(EXIT_FAILURE);
  }
}

static void
usage(FILE * const stream, const int status)
{
	fprintf(stream,
_("%s: usage: %s OPTIONS TIMEZONE ...\n"
  "Options include:\n"
  "  -c [L,]U   Start at year L (default -500), end before year U (default 2500)\n"
  "  -t [L,]U   Start at time L, end before time U (in seconds since 1970)\n"
  "  -i         List transitions briefly (format is experimental)\n" \
  "  -v         List transitions verbosely\n"
  "  -V         List transitions a bit less verbosely\n"
  "  --help     Output this help\n"
  "  --version  Output version info\n"
  "\n"
  "Report bugs to %s.\n"),
		progname, progname, REPORT_BUGS_TO);
	if (status == EXIT_SUCCESS)
	  close_file(stream);
	exit(status);
}

int
main(int argc, char *argv[])
{
	/* These are static so that they're initially zero.  */
	static char *		abbrev;
	static size_t		abbrevsize;

	register int		i;
	register bool		vflag;
	register bool		Vflag;
	register char *		cutarg;
	register char *		cuttimes;
	register time_t		cutlotime;
	register time_t		cuthitime;
	time_t			now;
	bool iflag = false;

	cutlotime = absolute_min_time;
	cuthitime = absolute_max_time;
#if HAVE_GETTEXT
	setlocale(LC_ALL, "");
#ifdef TZ_DOMAINDIR
	bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR);
#endif /* defined TEXTDOMAINDIR */
	textdomain(TZ_DOMAIN);
#endif /* HAVE_GETTEXT */
	progname = argv[0];
	for (i = 1; i < argc; ++i)
		if (strcmp(argv[i], "--version") == 0) {
			printf("zdump %s%s\n", PKGVERSION, TZVERSION);
			return EXIT_SUCCESS;
		} else if (strcmp(argv[i], "--help") == 0) {
			usage(stdout, EXIT_SUCCESS);
		}
	vflag = Vflag = false;
	cutarg = cuttimes = NULL;
	for (;;)
	  switch (getopt(argc, argv, "c:it:vV")) {
	  case 'c': cutarg = optarg; break;
	  case 't': cuttimes = optarg; break;
	  case 'i': iflag = true; break;
	  case 'v': vflag = true; break;
	  case 'V': Vflag = true; break;
	  case -1:
	    if (! (optind == argc - 1 && strcmp(argv[optind], "=") == 0))
	      goto arg_processing_done;
	    /* Fall through.  */
	  default:
	    usage(stderr, EXIT_FAILURE);
	  }
 arg_processing_done:;

	if (iflag | vflag | Vflag) {
		intmax_t	lo;
		intmax_t	hi;
		char *loend, *hiend;
		register intmax_t cutloyear = ZDUMP_LO_YEAR;
		register intmax_t cuthiyear = ZDUMP_HI_YEAR;
		if (cutarg != NULL) {
			lo = strtoimax(cutarg, &loend, 10);
			if (cutarg != loend && !*loend) {
				hi = lo;
				cuthiyear = hi;
			} else if (cutarg != loend && *loend == ','
				   && (hi = strtoimax(loend + 1, &hiend, 10),
				       loend + 1 != hiend && !*hiend)) {
				cutloyear = lo;
				cuthiyear = hi;
			} else {
				fprintf(stderr, _("%s: wild -c argument %s\n"),
					progname, cutarg);
				return EXIT_FAILURE;
			}
		}
		if (cutarg != NULL || cuttimes == NULL) {
			cutlotime = yeartot(cutloyear);
			cuthitime = yeartot(cuthiyear);
		}
		if (cuttimes != NULL) {
			lo = strtoimax(cuttimes, &loend, 10);
			if (cuttimes != loend && !*loend) {
				hi = lo;
				if (hi < cuthitime) {
					if (hi < absolute_min_time)
						hi = absolute_min_time;
					cuthitime = hi;
				}
			} else if (cuttimes != loend && *loend == ','
				   && (hi = strtoimax(loend + 1, &hiend, 10),
				       loend + 1 != hiend && !*hiend)) {
				if (cutlotime < lo) {
					if (absolute_max_time < lo)
						lo = absolute_max_time;
					cutlotime = lo;
				}
				if (hi < cuthitime) {
					if (hi < absolute_min_time)
						hi = absolute_min_time;
					cuthitime = hi;
				}
			} else {
				fprintf(stderr,
					_("%s: wild -t argument %s\n"),
					progname, cuttimes);
				return EXIT_FAILURE;
			}
		}
	}
	gmtzinit();
	INITIALIZE (now);
	if (! (iflag | vflag | Vflag))
	  now = time(NULL);
	longest = 0;
	for (i = optind; i < argc; i++) {
	  size_t arglen = strlen(argv[i]);
	  if (longest < arglen)
	    longest = arglen < INT_MAX ? arglen : INT_MAX;
	}

	for (i = optind; i < argc; ++i) {
		timezone_t tz = tzalloc(argv[i]);
		char const *ab;
		time_t t;
		struct tm tm, newtm;
		bool tm_ok;
		if (!tz) {
		  perror(argv[i]);
		  return EXIT_FAILURE;
		}
		if (! (iflag | vflag | Vflag)) {
			show(tz, argv[i], now, false);
			tzfree(tz);
			continue;
		}
		warned = false;
		t = absolute_min_time;
		if (! (iflag | Vflag)) {
			show(tz, argv[i], t, true);
			t += SECSPERDAY;
			show(tz, argv[i], t, true);
		}
		if (t < cutlotime)
			t = cutlotime;
		INITIALIZE (ab);
		tm_ok = my_localtime_rz(tz, &t, &tm) != NULL;
		if (tm_ok) {
		  ab = saveabbr(&abbrev, &abbrevsize, &tm);
		  if (iflag) {
		    showtrans("\nTZ=%f", &tm, t, ab, argv[i]);
		    showtrans("-\t-\t%Q", &tm, t, ab, argv[i]);
		  }
		}
		while (t < cuthitime) {
		  time_t newt = ((t < absolute_max_time - SECSPERDAY / 2
				  && t + SECSPERDAY / 2 < cuthitime)
				 ? t + SECSPERDAY / 2
				 : cuthitime);
		  struct tm *newtmp = localtime_rz(tz, &newt, &newtm);
		  bool newtm_ok = newtmp != NULL;
		  if (tm_ok != newtm_ok
		      || (tm_ok && (delta(&newtm, &tm) != newt - t
				    || newtm.tm_isdst != tm.tm_isdst
				    || strcmp(abbr(&newtm), ab) != 0))) {
		    newt = hunt(tz, argv[i], t, newt);
		    newtmp = localtime_rz(tz, &newt, &newtm);
		    newtm_ok = newtmp != NULL;
		    if (iflag)
		      showtrans("%Y-%m-%d\t%L\t%Q", newtmp, newt,
				newtm_ok ? abbr(&newtm) : NULL, argv[i]);
		    else {
		      show(tz, argv[i], newt - 1, true);
		      show(tz, argv[i], newt, true);
		    }
		  }
		  t = newt;
		  tm_ok = newtm_ok;
		  if (newtm_ok) {
		    ab = saveabbr(&abbrev, &abbrevsize, &newtm);
		    tm = newtm;
		  }
		}
		if (! (iflag | Vflag)) {
			t = absolute_max_time;
			t -= SECSPERDAY;
			show(tz, argv[i], t, true);
			t += SECSPERDAY;
			show(tz, argv[i], t, true);
		}
		tzfree(tz);
	}
	close_file(stdout);
	if (errout && (ferror(stderr) || fclose(stderr) != 0))
	  return EXIT_FAILURE;
	return EXIT_SUCCESS;
}

static time_t
yeartot(intmax_t y)
{
	register intmax_t	myy, seconds, years;
	register time_t		t;

	myy = EPOCH_YEAR;
	t = 0;
	while (myy < y) {
		if (SECSPER400YEARS_FITS && 400 <= y - myy) {
			intmax_t diff400 = (y - myy) / 400;
			if (INTMAX_MAX / SECSPER400YEARS < diff400)
				return absolute_max_time;
			seconds = diff400 * SECSPER400YEARS;
			years = diff400 * 400;
                } else {
			seconds = isleap(myy) ? SECSPERLYEAR : SECSPERNYEAR;
			years = 1;
		}
		myy += years;
		if (t > absolute_max_time - seconds)
			return absolute_max_time;
		t += seconds;
	}
	while (y < myy) {
		if (SECSPER400YEARS_FITS && y + 400 <= myy && myy < 0) {
			intmax_t diff400 = (myy - y) / 400;
			if (INTMAX_MAX / SECSPER400YEARS < diff400)
				return absolute_min_time;
			seconds = diff400 * SECSPER400YEARS;
			years = diff400 * 400;
		} else {
			seconds = isleap(myy - 1) ? SECSPERLYEAR : SECSPERNYEAR;
			years = 1;
		}
		myy -= years;
		if (t < absolute_min_time + seconds)
			return absolute_min_time;
		t -= seconds;
	}
	return t;
}

static time_t
hunt(timezone_t tz, char *name, time_t lot, time_t hit)
{
	static char *		loab;
	static size_t		loabsize;
	char const *		ab;
	time_t			t;
	struct tm		lotm;
	struct tm		tm;
	bool lotm_ok = my_localtime_rz(tz, &lot, &lotm) != NULL;
	bool tm_ok;

	if (lotm_ok)
	  ab = saveabbr(&loab, &loabsize, &lotm);
	for ( ; ; ) {
		time_t diff = hit - lot;
		if (diff < 2)
			break;
		t = lot;
		t += diff / 2;
		if (t <= lot)
			++t;
		else if (t >= hit)
			--t;
		tm_ok = my_localtime_rz(tz, &t, &tm) != NULL;
		if (lotm_ok & tm_ok
		    ? (delta(&tm, &lotm) == t - lot
		       && tm.tm_isdst == lotm.tm_isdst
		       && strcmp(abbr(&tm), ab) == 0)
		    : lotm_ok == tm_ok) {
		  lot = t;
		  if (tm_ok)
		    lotm = tm;
		} else	hit = t;
	}
	return hit;
}

/*
** Thanks to Paul Eggert for logic used in delta_nonneg.
*/

static intmax_t
delta_nonneg(struct tm *newp, struct tm *oldp)
{
	register intmax_t	result;
	register int		tmy;

	result = 0;
	for (tmy = oldp->tm_year; tmy < newp->tm_year; ++tmy)
		result += DAYSPERNYEAR + isleap_sum(tmy, TM_YEAR_BASE);
	result += newp->tm_yday - oldp->tm_yday;
	result *= HOURSPERDAY;
	result += newp->tm_hour - oldp->tm_hour;
	result *= MINSPERHOUR;
	result += newp->tm_min - oldp->tm_min;
	result *= SECSPERMIN;
	result += newp->tm_sec - oldp->tm_sec;
	return result;
}

static intmax_t
delta(struct tm *newp, struct tm *oldp)
{
  return (newp->tm_year < oldp->tm_year
	  ? -delta_nonneg(oldp, newp)
	  : delta_nonneg(newp, oldp));
}

#ifndef TM_GMTOFF
/* Return A->tm_yday, adjusted to compare it fairly to B->tm_yday.
   Assume A and B differ by at most one year.  */
static int
adjusted_yday(struct tm const *a, struct tm const *b)
{
  int yday = a->tm_yday;
  if (b->tm_year < a->tm_year)
    yday += 365 + isleap_sum(b->tm_year, TM_YEAR_BASE);
  return yday;
}
#endif

/* If A is the broken-down local time and B the broken-down UT for
   the same instant, return A's UT offset in seconds, where positive
   offsets are east of Greenwich.  On failure, return LONG_MIN.

   If T is nonnull, *T is the timestamp that corresponds to A; call
   my_gmtime_r and use its result instead of B.  Otherwise, B is the
   possibly nonnull result of an earlier call to my_gmtime_r.  */
static long
gmtoff(struct tm const *a, time_t *t, struct tm const *b)
{
#ifdef TM_GMTOFF
  return a->TM_GMTOFF;
#else
  struct tm tm;
  if (t)
    b = my_gmtime_r(t, &tm);
  if (! b)
    return LONG_MIN;
  else {
    int ayday = adjusted_yday(a, b);
    int byday = adjusted_yday(b, a);
    int days = ayday - byday;
    long hours = a->tm_hour - b->tm_hour + 24 * days;
    long minutes = a->tm_min - b->tm_min + 60 * hours;
    long seconds = a->tm_sec - b->tm_sec + 60 * minutes;
    return seconds;
  }
#endif
}

static void
show(timezone_t tz, char *zone, time_t t, bool v)
{
	register struct tm *	tmp;
	register struct tm *	gmtmp;
	struct tm tm, gmtm;

	printf("%-*s  ", longest, zone);
	if (v) {
		gmtmp = my_gmtime_r(&t, &gmtm);
		if (gmtmp == NULL) {
			printf(tformat(), t);
		} else {
			dumptime(gmtmp);
			printf(" UT");
		}
		printf(" = ");
	}
	tmp = my_localtime_rz(tz, &t, &tm);
	dumptime(tmp);
	if (tmp != NULL) {
		if (*abbr(tmp) != '\0')
			printf(" %s", abbr(tmp));
		if (v) {
			long off = gmtoff(tmp, NULL, gmtmp);
			printf(" isdst=%d", tmp->tm_isdst);
			if (off != LONG_MIN)
			  printf(" gmtoff=%ld", off);
		}
	}
	printf("\n");
	if (tmp != NULL && *abbr(tmp) != '\0')
		abbrok(abbr(tmp), zone);
}

#if HAVE_SNPRINTF
# define my_snprintf snprintf
#else
# include <stdarg.h>

/* A substitute for snprintf that is good enough for zdump.  */
static int ATTRIBUTE_FORMAT((printf, 3, 4))
my_snprintf(char *s, size_t size, char const *format, ...)
{
  int n;
  va_list args;
  char const *arg;
  size_t arglen, slen;
  char buf[1024];
  va_start(args, format);
  if (strcmp(format, "%s") == 0) {
    arg = va_arg(args, char const *);
    arglen = strlen(arg);
  } else {
    n = vsprintf(buf, format, args);
    if (n < 0) {
      va_end(args);
      return n;
    }
    arg = buf;
    arglen = n;
  }
  slen = arglen < size ? arglen : size - 1;
  memcpy(s, arg, slen);
  s[slen] = '\0';
  n = arglen <= INT_MAX ? arglen : -1;
  va_end(args);
  return n;
}
#endif

/* Store into BUF, of size SIZE, a formatted local time taken from *TM.
   Use ISO 8601 format +HH:MM:SS.  Omit :SS if SS is zero, and omit
   :MM too if MM is also zero.

   Return the length of the resulting string.  If the string does not
   fit, return the length that the string would have been if it had
   fit; do not overrun the output buffer.  */
static int
format_local_time(char *buf, size_t size, struct tm const *tm)
{
  int ss = tm->tm_sec, mm = tm->tm_min, hh = tm->tm_hour;
  return (ss
	  ? my_snprintf(buf, size, "%02d:%02d:%02d", hh, mm, ss)
	  : mm
	  ? my_snprintf(buf, size, "%02d:%02d", hh, mm)
	  : my_snprintf(buf, size, "%02d", hh));
}

/* Store into BUF, of size SIZE, a formatted UT offset for the
   localtime *TM corresponding to time T.  Use ISO 8601 format
   +HHMMSS, or -HHMMSS for timestamps west of Greenwich; use the
   format -00 for unknown UT offsets.  If the hour needs more than
   two digits to represent, extend the length of HH as needed.
   Otherwise, omit SS if SS is zero, and omit MM too if MM is also
   zero.

   Return the length of the resulting string, or -1 if the result is
   not representable as a string.  If the string does not fit, return
   the length that the string would have been if it had fit; do not
   overrun the output buffer.  */
static int
format_utc_offset(char *buf, size_t size, struct tm const *tm, time_t t)
{
  long off = gmtoff(tm, &t, NULL);
  char sign = ((off < 0
		|| (off == 0
		    && (*abbr(tm) == '-' || strcmp(abbr(tm), "zzz") == 0)))
	       ? '-' : '+');
  long hh;
  int mm, ss;
  if (off < 0)
    {
      if (off == LONG_MIN)
	return -1;
      off = -off;
    }
  ss = off % 60;
  mm = off / 60 % 60;
  hh = off / 60 / 60;
  return (ss || 100 <= hh
	  ? my_snprintf(buf, size, "%c%02ld%02d%02d", sign, hh, mm, ss)
	  : mm
	  ? my_snprintf(buf, size, "%c%02ld%02d", sign, hh, mm)
	  : my_snprintf(buf, size, "%c%02ld", sign, hh));
}

/* Store into BUF (of size SIZE) a quoted string representation of P.
   If the representation's length is less than SIZE, return the
   length; the representation is not null terminated.  Otherwise
   return SIZE, to indicate that BUF is too small.  */
static size_t
format_quoted_string(char *buf, size_t size, char const *p)
{
  char *b = buf;
  size_t s = size;
  if (!s)
    return size;
  *b++ = '"', s--;
  for (;;) {
    char c = *p++;
    if (s <= 1)
      return size;
    switch (c) {
    default: *b++ = c, s--; continue;
    case '\0': *b++ = '"', s--; return size - s;
    case '"': case '\\': break;
    case ' ': c = 's'; break;
    case '\f': c = 'f'; break;
    case '\n': c = 'n'; break;
    case '\r': c = 'r'; break;
    case '\t': c = 't'; break;
    case '\v': c = 'v'; break;
    }
    *b++ = '\\', *b++ = c, s -= 2;
  }
}

/* Store into BUF (of size SIZE) a timestamp formatted by TIME_FMT.
   TM is the broken-down time, T the seconds count, AB the time zone
   abbreviation, and ZONE_NAME the zone name.  Return true if
   successful, false if the output would require more than SIZE bytes.
   TIME_FMT uses the same format that strftime uses, with these
   additions:

   %f zone name
   %L local time as per format_local_time
   %Q like "U\t%Z\tD" where U is the UT offset as for format_utc_offset
      and D is the isdst flag; except omit D if it is zero, omit %Z if
      it equals U, quote and escape %Z if it contains nonalphabetics,
      and omit any trailing tabs.  */

static bool
istrftime(char *buf, size_t size, char const *time_fmt,
	  struct tm const *tm, time_t t, char const *ab, char const *zone_name)
{
  char *b = buf;
  size_t s = size;
  char const *f = time_fmt, *p;

  for (p = f; ; p++)
    if (*p == '%' && p[1] == '%')
      p++;
    else if (!*p
	     || (*p == '%'
		 && (p[1] == 'f' || p[1] == 'L' || p[1] == 'Q'))) {
      size_t formatted_len;
      size_t f_prefix_len = p - f;
      size_t f_prefix_copy_size = p - f + 2;
      char fbuf[100];
      bool oversized = sizeof fbuf <= f_prefix_copy_size;
      char *f_prefix_copy = oversized ? xmalloc(f_prefix_copy_size) : fbuf;
      memcpy(f_prefix_copy, f, f_prefix_len);
      strcpy(f_prefix_copy + f_prefix_len, "X");
      formatted_len = strftime(b, s, f_prefix_copy, tm);
      if (oversized)
	free(f_prefix_copy);
      if (formatted_len == 0)
	return false;
      formatted_len--;
      b += formatted_len, s -= formatted_len;
      if (!*p++)
	break;
      switch (*p) {
      case 'f':
	formatted_len = format_quoted_string(b, s, zone_name);
	break;
      case 'L':
	formatted_len = format_local_time(b, s, tm);
	break;
      case 'Q':
	{
	  bool show_abbr;
	  int offlen = format_utc_offset(b, s, tm, t);
	  if (! (0 <= offlen && offlen < s))
	    return false;
	  show_abbr = strcmp(b, ab) != 0;
	  b += offlen, s -= offlen;
	  if (show_abbr) {
	    char const *abp;
	    size_t len;
	    if (s <= 1)
	      return false;
	    *b++ = '\t', s--;
	    for (abp = ab; is_alpha(*abp); abp++)
	      continue;
	    len = (!*abp && *ab
		   ? my_snprintf(b, s, "%s", ab)
		   : format_quoted_string(b, s, ab));
	    if (s <= len)
	      return false;
	    b += len, s -= len;
	  }
	  formatted_len
	    = (tm->tm_isdst
	       ? my_snprintf(b, s, &"\t\t%d"[show_abbr], tm->tm_isdst)
	       : 0);
	}
	break;
      }
      if (s <= formatted_len)
	return false;
      b += formatted_len, s -= formatted_len;
      f = p + 1;
    }
  *b = '\0';
  return true;
}

/* Show a time transition.  */
static void
showtrans(char const *time_fmt, struct tm const *tm, time_t t, char const *ab,
	  char const *zone_name)
{
  if (!tm) {
    printf(tformat(), t);
    putchar('\n');
  } else {
    char stackbuf[1000];
    size_t size = sizeof stackbuf;
    char *buf = stackbuf;
    char *bufalloc = NULL;
    while (! istrftime(buf, size, time_fmt, tm, t, ab, zone_name)) {
      size = sumsize(size, size);
      free(bufalloc);
      buf = bufalloc = xmalloc(size);
    }
    puts(buf);
    free(bufalloc);
  }
}

static char const *
abbr(struct tm const *tmp)
{
#ifdef TM_ZONE
	return tmp->TM_ZONE;
#else
# if HAVE_TZNAME
	if (0 <= tmp->tm_isdst && tzname[0 < tmp->tm_isdst])
	  return tzname[0 < tmp->tm_isdst];
# endif
	return "";
#endif
}

/*
** The code below can fail on certain theoretical systems;
** it works on all known real-world systems as of 2004-12-30.
*/

static const char *
tformat(void)
{
	if (0 > (time_t) -1) {		/* signed */
		if (sizeof (time_t) == sizeof (intmax_t))
			return "%"PRIdMAX;
		if (sizeof (time_t) > sizeof (long))
			return "%lld";
		if (sizeof (time_t) > sizeof (int))
			return "%ld";
		return "%d";
	}
#ifdef PRIuMAX
	if (sizeof (time_t) == sizeof (uintmax_t))
		return "%"PRIuMAX;
#endif
	if (sizeof (time_t) > sizeof (unsigned long))
		return "%llu";
	if (sizeof (time_t) > sizeof (unsigned int))
		return "%lu";
	return "%u";
}

static void
dumptime(register const struct tm *timeptr)
{
	static const char	wday_name[][4] = {
		"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
	};
	static const char	mon_name[][4] = {
		"Jan", "Feb", "Mar", "Apr", "May", "Jun",
		"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
	};
	register const char *	wn;
	register const char *	mn;
	register int		lead;
	register int		trail;

	if (timeptr == NULL) {
		printf("NULL");
		return;
	}
	/*
	** The packaged localtime_rz and gmtime_r never put out-of-range
	** values in tm_wday or tm_mon, but since this code might be compiled
	** with other (perhaps experimental) versions, paranoia is in order.
	*/
	if (timeptr->tm_wday < 0 || timeptr->tm_wday >=
		(int) (sizeof wday_name / sizeof wday_name[0]))
			wn = "???";
	else		wn = wday_name[timeptr->tm_wday];
	if (timeptr->tm_mon < 0 || timeptr->tm_mon >=
		(int) (sizeof mon_name / sizeof mon_name[0]))
			mn = "???";
	else		mn = mon_name[timeptr->tm_mon];
	printf("%s %s%3d %.2d:%.2d:%.2d ",
		wn, mn,
		timeptr->tm_mday, timeptr->tm_hour,
		timeptr->tm_min, timeptr->tm_sec);
#define DIVISOR	10
	trail = timeptr->tm_year % DIVISOR + TM_YEAR_BASE % DIVISOR;
	lead = timeptr->tm_year / DIVISOR + TM_YEAR_BASE / DIVISOR +
		trail / DIVISOR;
	trail %= DIVISOR;
	if (trail < 0 && lead > 0) {
		trail += DIVISOR;
		--lead;
	} else if (lead < 0 && trail > 0) {
		trail -= DIVISOR;
		++lead;
	}
	if (lead == 0)
		printf("%d", trail);
	else	printf("%d%d", lead, ((trail < 0) ? -trail : trail));
}