summaryrefslogtreecommitdiffstats
path: root/generic/tclClock.c
blob: 891ea258adebf32d9da41e805365059ebd9c77df (plain)
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
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
/*
 * tclClock.c --
 *
 *	Contains the time and date related commands. This code is derived from
 *	the time and date facilities of TclX, by Mark Diekhans and Karl
 *	Lehenbauer.
 *
 * Copyright 1991-1995 Karl Lehenbauer and Mark Diekhans.
 * Copyright (c) 1995 Sun Microsystems, Inc.
 * Copyright (c) 2004 by Kevin B. Kenny.  All rights reserved.
 *
 * See the file "license.terms" for information on usage and redistribution of
 * this file, and for a DISCLAIMER OF ALL WARRANTIES.
 *
 * RCS: @(#) $Id: tclClock.c,v 1.45 2005/11/30 15:09:41 kennykb Exp $
 */

#include "tclInt.h"

/*
 * Windows has mktime. The configurators do not check.
 */

#ifdef __WIN32__
#define HAVE_MKTIME 1
#endif

/*
 * Constants
 */

#define JULIAN_DAY_POSIX_EPOCH		2440588
#define SECONDS_PER_DAY			86400
#define JULIAN_SEC_POSIX_EPOCH	      (((Tcl_WideInt) JULIAN_DAY_POSIX_EPOCH) \
                                       * SECONDS_PER_DAY)
#define FOUR_CENTURIES			146097 /* days */
#define JDAY_1_JAN_1_CE_JULIAN		1721424
#define JDAY_1_JAN_1_CE_GREGORIAN	1721426
#define ONE_CENTURY_GREGORIAN		36524  /* days */
#define FOUR_YEARS			1461   /* days */
#define ONE_YEAR			365    /* days */

/*
 * Table of the days in each month, leap and common years
 */

static const int hath[2][12] = {
    {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
    {31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}
};
static const int daysInPriorMonths[2][13] = {
    {0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365},
    {0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366}
};

/*
 * Enumeration of the string literals used in [clock]
 */

typedef enum ClockLiteral {
    LIT_BCE,		LIT_CE,		    
    LIT_DAYOFMONTH,	LIT_DAYOFWEEK,	    LIT_DAYOFYEAR,
    LIT_ERA,            LIT_GREGORIAN,	
    LIT_ISO8601WEEK,	LIT_ISO8601YEAR,
    LIT_JULIANDAY,	LIT_LOCALSECONDS,
    LIT_MONTH,
    LIT_SECONDS,	LIT_TZNAME,	    LIT_TZOFFSET,
    LIT_YEAR,
    LIT__END
} ClockLiteral;
static const char *const literals[] = {
    "BCE",		"CE",		    
    "dayOfMonth",	"dayOfWeek",	    "dayOfYear",
    "era",	        "gregorian",	
    "iso8601Week",	"iso8601Year",
    "julianDay",	"localSeconds",
    "month",
    "seconds",		"tzName",      	    "tzOffset",
    "year"
};

/*
 * Structure containing the client data for [clock]
 */

typedef struct ClockClientData {
    int refCount;		/* Number of live references */
    Tcl_Obj** literals;		/* Pool of object literals */
} ClockClientData;

/*
 * Structure containing the fields used in [clock format] and [clock scan]
 */

typedef struct TclDateFields {
    Tcl_WideInt seconds;	/* Time expressed in seconds from the
				 * Posix epoch */
    Tcl_WideInt localSeconds;	/* Local time expressed in nominal seconds
				 * from the Posix epoch */
    int tzOffset;		/* Time zone offset in seconds east of
				 * Greenwich */
    Tcl_Obj* tzName;		/* Time zone name */
    int julianDay;		/* Julian Day Number in local time zone */
    enum {BCE=1, CE=0} era;	/* Era */
    int gregorian;		/* Flag == 1 if the date is Gregorian */
    int year;			/* Year of the era */
    int dayOfYear;		/* Day of the year (1 January == 1) */
    int month;			/* Month number */
    int dayOfMonth;		/* Day of the month */
    int iso8601Year;		/* ISO8601 week-based year */
    int iso8601Week;		/* ISO8601 week number */
    int dayOfWeek;		/* Day of the week */
    
} TclDateFields;

/*
 * Thread specific data block holding a 'struct tm' for the 'gmtime' and
 * 'localtime' library calls.
 */

static Tcl_ThreadDataKey tmKey;

/*
 * Mutex protecting 'gmtime', 'localtime' and 'mktime' calls and the statics
 * in the date parsing code.
 */

TCL_DECLARE_MUTEX(clockMutex)

/*
 * Function prototypes for local procedures in this file:
 */

static int		ConvertUTCToLocal(Tcl_Interp*, 
			    TclDateFields*, Tcl_Obj*, int);
static int		ConvertUTCToLocalUsingTable(Tcl_Interp*, 
			    TclDateFields*, int, Tcl_Obj *CONST[]);
static int		ConvertUTCToLocalUsingC(Tcl_Interp*, 
			    TclDateFields*, int);
static int		ConvertLocalToUTC(Tcl_Interp*, 
			    TclDateFields*, Tcl_Obj*, int);
static int		ConvertLocalToUTCUsingTable(Tcl_Interp*, 
			    TclDateFields*, int, Tcl_Obj *CONST[]);
static int		ConvertLocalToUTCUsingC(Tcl_Interp*, 
			    TclDateFields*, int);
static Tcl_Obj*		LookupLastTransition(Tcl_Interp*, Tcl_WideInt,
			    int, Tcl_Obj *CONST *);
static void		GetYearWeekDay(TclDateFields*, int);
static void		GetGregorianEraYearDay(TclDateFields*, int);
static void		GetMonthDay(TclDateFields*);
static void		GetJulianDayFromEraYearWeekDay(TclDateFields*, int);
static void		GetJulianDayFromEraYearMonthDay(TclDateFields*, int);
static int		IsGregorianLeapYear(TclDateFields*);
static int		WeekdayOnOrBefore(int, int);
static int		ClockClicksObjCmd(
			    ClientData clientData, Tcl_Interp *interp,
			    int objc, Tcl_Obj *CONST objv[]);
static int		ClockConvertlocaltoutcObjCmd(
			    ClientData clientData, Tcl_Interp *interp,
			    int objc, Tcl_Obj *CONST objv[]);
static int		ClockGetdatefieldsObjCmd(
			    ClientData clientData, Tcl_Interp *interp,
			    int objc, Tcl_Obj *CONST objv[]);
static int		ClockGetenvObjCmd(
			    ClientData clientData, Tcl_Interp *interp,
			    int objc, Tcl_Obj *CONST objv[]);
static int		ClockMicrosecondsObjCmd(
			    ClientData clientData, Tcl_Interp *interp,
			    int objc, Tcl_Obj *CONST objv[]);
static int		ClockMillisecondsObjCmd(
			    ClientData clientData, Tcl_Interp *interp,
			    int objc, Tcl_Obj *CONST objv[]);
static int		ClockSecondsObjCmd(
			    ClientData clientData, Tcl_Interp *interp,
			    int objc, Tcl_Obj *CONST objv[]);
static struct tm *	ThreadSafeLocalTime(CONST time_t *);
static void		TzsetIfNecessary(void);
static void		ClockDeleteCmdProc(ClientData);


/*
 *----------------------------------------------------------------------
 *
 * TclClockInit --
 *
 *	Registers the 'clock' subcommands with the Tcl interpreter
 *	and initializes its client data (which consists mostly of
 *	constant Tcl_Obj's that it is too much trouble to keep
 *	recreating).
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Installs the commands and creates the client data
 *
 *----------------------------------------------------------------------
 */

void
TclClockInit(
    Tcl_Interp* interp		/* Tcl interpreter */
) {
    int i;

    /* Create the client data */

    ClockClientData *data =
	(ClockClientData*) ckalloc(sizeof(ClockClientData));
    data->refCount = 0;
    
    /*
     * Create the literal pool
     */
    data->literals = (Tcl_Obj**) ckalloc(LIT__END * sizeof(Tcl_Obj*));
    for (i = 0; i < LIT__END; ++i) {
	data->literals[i] = Tcl_NewStringObj(literals[i], -1);
	Tcl_IncrRefCount(data->literals[i]);
    }

    /* Install the commands */

    Tcl_CreateObjCommand(interp,	"::tcl::clock::clicks",
	    ClockClicksObjCmd,	(ClientData) NULL, NULL);
    Tcl_CreateObjCommand(interp,	"::tcl::clock::getenv",
	    ClockGetenvObjCmd,	(ClientData) NULL, NULL);
    Tcl_CreateObjCommand(interp,	"::tcl::clock::microseconds",
	    ClockMicrosecondsObjCmd,	(ClientData) NULL, NULL);
    Tcl_CreateObjCommand(interp,	"::tcl::clock::milliseconds",
	    ClockMillisecondsObjCmd,	(ClientData) NULL, NULL);
    Tcl_CreateObjCommand(interp,	"::tcl::clock::seconds",
	    ClockSecondsObjCmd,	(ClientData) NULL, NULL);
    Tcl_CreateObjCommand(interp,	"::tcl::clock::Oldscan",
	    TclClockOldscanObjCmd,	(ClientData) NULL, NULL);
    Tcl_CreateObjCommand(interp,	"::tcl::clock::ConvertLocalToUTC",
	    ClockConvertlocaltoutcObjCmd, (ClientData) data,
	    ClockDeleteCmdProc);
    ++data->refCount;
    Tcl_CreateObjCommand(interp,	"::tcl::clock::GetDateFields",
	    ClockGetdatefieldsObjCmd,(ClientData) data,
	    ClockDeleteCmdProc);
    ++data->refCount;

}

/*
 *----------------------------------------------------------------------
 *
 * ClockConvertlocaltoutcObjCmd --
 *
 *	Tcl command that converts a UTC time to a local time by
 *	whatever means is available.
 *
 * Usage:
 *	::tcl::clock::ConvertUTCToLocal dictionary tzdata changeover
 *
 * Parameters:
 *	dict - Dictionary containing a 'localSeconds' entry.
 *	tzdata - Time zone data
 *	changeover - Julian Day of the adoption of the Gregorian calendar.
 *
 * Results:
 *	Returns a standard Tcl result.
 *
 * Side effects:
 *	On success, sets the interpreter result to the given dictionary
 *	augmented with a 'seconds' field giving the UTC time.  On failure,
 *	leaves an error message in the interpreter result.
 *
 *----------------------------------------------------------------------
 */

static int
ClockConvertlocaltoutcObjCmd(
    ClientData clientData,	/* Client data  */
    Tcl_Interp* interp,		/* Tcl interpreter */
    int objc,			/* Parameter count */
    Tcl_Obj *CONST * objv	/* Parameter vector */
) {
    ClockClientData* data = (ClockClientData*) clientData;
    Tcl_Obj* CONST * literals = data->literals;
    Tcl_Obj* secondsObj;
    Tcl_Obj* dict;
    int changeover;
    TclDateFields fields;
    int created = 0;
    int status;

    /* Check params and convert time */

    if (objc != 4) {
	Tcl_WrongNumArgs(interp, 1, objv, "dict tzdata changeover");
	return TCL_ERROR;
    }
    dict = objv[1];
    if ((Tcl_DictObjGet(interp, dict, literals[LIT_LOCALSECONDS], &secondsObj)
	 != TCL_OK)
	|| (Tcl_GetWideIntFromObj(interp, secondsObj, &(fields.localSeconds))
	    != TCL_OK)
	|| (Tcl_GetIntFromObj(interp, objv[3], &changeover) != TCL_OK)
	|| ConvertLocalToUTC(interp, &fields, objv[2], changeover)) {
	return TCL_ERROR;
    }

    /* 
     * Copy-on-write; set the 'seconds' field in the dictionary and
     * place the modified dictionary in the interpreter result.
     */

    if (Tcl_IsShared(dict)) {
	dict = Tcl_DuplicateObj(dict);
	created = 1;
	Tcl_IncrRefCount(dict);
    }
    status = Tcl_DictObjPut(interp, dict, literals[LIT_SECONDS],
			    Tcl_NewWideIntObj(fields.seconds));
    if (status == TCL_OK) {
	Tcl_SetObjResult(interp, dict);
    }
    if (created) {
	Tcl_DecrRefCount(dict);
    }
    return status;
}

/*
 *----------------------------------------------------------------------
 *
 * ClockGetdatefieldsObjCmd --
 *
 *	Tcl command that determines the values that [clock format] will
 *	use in formatting a date, and populates a dictionary with them.
 *
 * Usage:
 *	::tcl::clock::GetDateFields seconds tzdata changeover
 *
 * Parameters:
 *	seconds - Time expressed in seconds from the Posix epoch.
 *	tzdata - Time zone data of the time zone in which time is to 
 *                 be expressed.
 *	changeover - Julian Day Number at which the current locale adopted
 *		     the Gregorian calendar
 *
 * Results:
 *	Returns a dictonary populated with the fields:
 *		seconds - Seconds from the Posix epoch
 *		localSeconds - Nominal seconds from the Posix epoch in
 *			       the local time zone.
 *		tzOffset - Time zone offset in seconds east of Greenwich
 *		tzName - Time zone name
 *		julianDay - Julian Day Number in the local time zone
 *
 *----------------------------------------------------------------------
 */

int
ClockGetdatefieldsObjCmd(
    ClientData clientData,	/* Opaque pointer to literal pool, etc. */
    Tcl_Interp* interp,		/* Tcl interpreter */
    int objc,			/* Parameter count */
    Tcl_Obj *CONST *objv	/* Parameter vector */
) {
    TclDateFields fields;
    Tcl_Obj* dict;
    ClockClientData* data = (ClockClientData*) clientData;
    Tcl_Obj* CONST * literals = data->literals;
    int changeover;

    /* Check params */

    if (objc != 4) {
	Tcl_WrongNumArgs(interp, 1, objv, "seconds tzdata changeover");
	return TCL_ERROR;
    }
    if (Tcl_GetWideIntFromObj(interp, objv[1], &(fields.seconds)) != TCL_OK
	|| Tcl_GetIntFromObj(interp, objv[3], &changeover) != TCL_OK) {
	return TCL_ERROR;
    }

    /* Convert UTC time to local */

    if (ConvertUTCToLocal(interp, &fields, objv[2], changeover) != TCL_OK) {
	return TCL_ERROR;
    }

    /* Extract Julian day */

    fields.julianDay = (int) ((fields.localSeconds + JULIAN_SEC_POSIX_EPOCH)
			      / SECONDS_PER_DAY);

    /* Convert to Julian or Gregorian calendar */

    GetGregorianEraYearDay(&fields, changeover);
    GetMonthDay(&fields);
    GetYearWeekDay(&fields, changeover);

    dict = Tcl_NewDictObj();
    Tcl_DictObjPut((Tcl_Interp*) NULL, dict, literals[LIT_LOCALSECONDS],
		   Tcl_NewWideIntObj(fields.localSeconds));
    Tcl_DictObjPut((Tcl_Interp*) NULL, dict, literals[LIT_SECONDS],
		   Tcl_NewWideIntObj(fields.seconds));
    Tcl_DictObjPut((Tcl_Interp*) NULL, dict, literals[LIT_TZNAME],
		   fields.tzName);
    Tcl_DecrRefCount(fields.tzName);
    Tcl_DictObjPut((Tcl_Interp*) NULL, dict, literals[LIT_TZOFFSET],
		   Tcl_NewIntObj(fields.tzOffset));
    Tcl_DictObjPut((Tcl_Interp*) NULL, dict, literals[LIT_JULIANDAY],
		   Tcl_NewWideIntObj(fields.julianDay));
    Tcl_DictObjPut((Tcl_Interp*) NULL, dict, literals[LIT_GREGORIAN],
		   Tcl_NewIntObj(fields.gregorian));
    Tcl_DictObjPut((Tcl_Interp*) NULL, dict, literals[LIT_ERA],
		   literals[fields.era ? LIT_BCE : LIT_CE]);
    Tcl_DictObjPut((Tcl_Interp*) NULL, dict, literals[LIT_YEAR],
		   Tcl_NewIntObj(fields.year));
    Tcl_DictObjPut((Tcl_Interp*) NULL, dict, literals[LIT_DAYOFYEAR],
		   Tcl_NewIntObj(fields.dayOfYear));
    Tcl_DictObjPut((Tcl_Interp*) NULL, dict, literals[LIT_MONTH],
		   Tcl_NewIntObj(fields.month));
    Tcl_DictObjPut((Tcl_Interp*) NULL, dict, literals[LIT_DAYOFMONTH],
		   Tcl_NewIntObj(fields.dayOfMonth));
    Tcl_DictObjPut((Tcl_Interp*) NULL, dict, literals[LIT_ISO8601YEAR],
		   Tcl_NewIntObj(fields.iso8601Year));
    Tcl_DictObjPut((Tcl_Interp*) NULL, dict, literals[LIT_ISO8601WEEK],
		   Tcl_NewIntObj(fields.iso8601Week));
    Tcl_DictObjPut((Tcl_Interp*) NULL, dict, literals[LIT_DAYOFWEEK],
		   Tcl_NewIntObj(fields.dayOfWeek));
    Tcl_SetObjResult(interp, dict);

    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * ConvertLocalToUTC --
 *
 *	Converts a time (in a TclDateFields structure) from the
 *	local wall clock to UTC.
 *
 * Results:
 *	Returns a standard Tcl result.
 *
 * Side effects:
 *	Populates the 'seconds' field if successful; stores an error
 *	message in the interpreter result on failure.
 *
 *----------------------------------------------------------------------
 */

static int
ConvertLocalToUTC(
    Tcl_Interp* interp,		/* Tcl interpreter */
    TclDateFields* fields,	/* Fields of the time */
    Tcl_Obj* tzdata,		/* Time zone data */
    int changeover		/* Julian Day of the Gregorian transition */
) {
    int rowc;			/* Number of rows in tzdata */
    Tcl_Obj** rowv;		/* Pointers to the rows */

    /* unpack the tz data */

    if (Tcl_ListObjGetElements(interp, tzdata, &rowc, &rowv) != TCL_OK) {
	return TCL_ERROR;
    }

    /* 
     * Special case: If the time zone is :localtime, the tzdata will be empty.
     * Use 'mktime' to convert the time to local
     */

    if (rowc == 0) {
	return ConvertLocalToUTCUsingC(interp, fields, changeover);
    } else {
	return ConvertLocalToUTCUsingTable(interp, fields, rowc, rowv);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * ConvertLocalToUTCUsingTable --
 *
 *	Converts a time (in a TclDateFields structure) from local time
 *	in a given time zone to UTC.
 *
 * Results:
 *	Returns a standard Tcl result.
 *
 * Side effects:
 *	Stores an error message in the interpreter if an error occurs;
 *	if successful, stores the 'seconds' field in 'fields.
 *
 *----------------------------------------------------------------------
 */
static int
ConvertLocalToUTCUsingTable(
    Tcl_Interp* interp,		/* Tcl interpreter */
    TclDateFields* fields,	/* Time to convert, with 'seconds' filled in */
    int rowc,			/* Number of points at which time changes */
    Tcl_Obj *CONST rowv[]	/* Points at which time changes */
) {
    Tcl_Obj* row;
    int cellc;
    Tcl_Obj** cellv;
    int have[8];
    int nHave = 0;
    int i;
    int found;

    /*
     * Perform an initial lookup assuming that local == UTC, and locate
     * the last time conversion prior to that time.  Get the offset from
     * that row, and look up again.  Continue until we find an offset
     * that we found before. This definition, rather than "the same offset"
     * ensures that we don't enter an endless loop, as would otherwise happen
     * when trying to convert a non-existent time such as 02:30 during
     * the US Spring Daylight Saving Time transition.
     */

    found = 0;
    fields->tzOffset = 0;
    fields->seconds = fields->localSeconds;
    while (!found) {
	row = LookupLastTransition(interp, fields->seconds, rowc, rowv);
	if ((row == NULL)
	    || (Tcl_ListObjGetElements(interp, row, &cellc, &cellv) != TCL_OK) 
	    || (Tcl_GetIntFromObj(interp, cellv[1], &(fields->tzOffset))
		!= TCL_OK)) {
	    return TCL_ERROR;
	}
	found = 0;
	for (i = 0; !found && i < nHave; ++i) {
	    if (have[i] == fields->tzOffset) {
		found = 1;
		break;
	    } 
	}
	if (!found) {
	    if (nHave == 8) {
		Tcl_Panic("loop in ConvertLocalToUTCUsingTable");
	    }
	    have[nHave] = fields->tzOffset;
	    ++nHave;
	}
	fields->seconds = fields->localSeconds - fields->tzOffset;
    }
    fields->tzOffset = have[i];
    fields->seconds = fields->localSeconds - fields->tzOffset;
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * ConvertLocalToUTCUsingC --
 *
 *	Converts a time from local wall clock to UTC when the local
 *	time zone cannot be determined.  Uses 'mktime' to do the job.
 *
 * Results:
 *	Returns a standard Tcl result.
 *
 * Side effects:
 *	Stores an error message in the interpreter if an error occurs;
 *	if successful, stores the 'seconds' field in 'fields.
 *
 *----------------------------------------------------------------------
 */

static int
ConvertLocalToUTCUsingC(
    Tcl_Interp* interp,		/* Tcl interpreter */
    TclDateFields* fields,	/* Time to convert, with 'seconds' filled in */
    int changeover		/* Julian Day of the Gregorian transition */
) {
    struct tm timeVal;
    int localErrno;

    /* Convert the given time to a date */

    fields->julianDay = (int) ((fields->localSeconds + JULIAN_SEC_POSIX_EPOCH)
			       / SECONDS_PER_DAY);
    GetGregorianEraYearDay(fields, changeover);
    GetMonthDay(fields);
 
    /* Convert the date/time to a 'struct tm' */

    timeVal.tm_year = fields->year - 1900;
    timeVal.tm_mon = fields->month - 1;
    timeVal.tm_mday = fields->dayOfMonth;
    timeVal.tm_hour = (int)((fields->localSeconds / 3600) % 24);
    timeVal.tm_min = (int)((fields->localSeconds / 60) % 60);
    timeVal.tm_sec = (int)(fields->localSeconds % 60);
    timeVal.tm_isdst = -1;
    timeVal.tm_wday = -1;
    timeVal.tm_yday = -1;

    /* 
     * Get local time. It is rumored that mktime is not thread safe
     * on some platforms, so seize a mutex before attempting this. 
     */

    TzsetIfNecessary();
    Tcl_MutexLock(&clockMutex);
    errno = 0;
    fields->seconds = (Tcl_WideInt) mktime(&timeVal);
    localErrno = errno;
    Tcl_MutexUnlock(&clockMutex);

    /* If conversion fails, report an error */

    if (localErrno != 0
	|| (fields->seconds == -1 && timeVal.tm_yday == -1)) {
	Tcl_SetObjResult(interp, 
			 Tcl_NewStringObj( "time value too large/small to "
					   "represent", -1));
	return TCL_ERROR;
    }
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * ConvertUTCToLocal --
 *
 *	Converts a time (in a TclDateFields structure) from UTC to
 *	local time.
 *
 * Results:
 *	Returns a standard Tcl result.
 *
 * Side effects:
 *	Populates the 'tzName' and 'tzOffset' fields.
 *
 *----------------------------------------------------------------------
 */

static int
ConvertUTCToLocal(
    Tcl_Interp* interp,		/* Tcl interpreter */
    TclDateFields* fields,	/* Fields of the time */
    Tcl_Obj* tzdata,		/* Time zone data */
    int changeover		/* Julian Day of the Gregorian transition */
) {
    int rowc;			/* Number of rows in tzdata */
    Tcl_Obj** rowv;		/* Pointers to the rows */

    /* unpack the tz data */

    if (Tcl_ListObjGetElements(interp, tzdata, &rowc, &rowv) != TCL_OK) {
	return TCL_ERROR;
    }

    /* 
     * Special case: If the time zone is :localtime, the tzdata will be empty.
     * Use 'localtime' to convert the time to local
     */

    if (rowc == 0) {
	return ConvertUTCToLocalUsingC(interp, fields, changeover);
    } else {
	return ConvertUTCToLocalUsingTable(interp, fields, rowc, rowv);
    }

}

/*
 *----------------------------------------------------------------------
 *
 * ConvertUTCToLocalUsingTable --
 *
 *	Converts UTC to local time, given a table of transition points
 *
 * Results:
 *	Returns a standard Tcl result
 *
 * Side effects:
 *	On success, fills fields->tzName, fields->tzOffset and
 *	fields->localSeconds.  On failure, places an error message in
 *	the interpreter result.
 *
 *----------------------------------------------------------------------
 */

static int
ConvertUTCToLocalUsingTable(
    Tcl_Interp* interp,		/* Tcl interpreter */
    TclDateFields* fields,	/* Fields of the date */
    int rowc,			/* Number of rows in the conversion table
				 * (>= 1) */
    Tcl_Obj *CONST rowv[]	/* Rows of the conversion table */
) {

    Tcl_Obj* row;		/* Row containing the current information */
    int cellc;		/* Count of cells in the row (must be 4) */
    Tcl_Obj** cellv;	/* Pointers to the cells */

    /* Look up the nearest transition time */

    row = LookupLastTransition(interp, fields->seconds, rowc, rowv);
    if (row == NULL
	|| (Tcl_ListObjGetElements(interp, row, &cellc, &cellv) != TCL_OK)
	|| (Tcl_GetIntFromObj(interp, cellv[1], &(fields->tzOffset))
	    != TCL_OK)) {
	return TCL_ERROR;
    }

    /* Convert the time */

    fields->tzName = cellv[3];
    Tcl_IncrRefCount(fields->tzName);
    fields->localSeconds = fields->seconds + fields->tzOffset;
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * ConvertUTCToLocalUsingC --
 *
 *	Converts UTC to localtime in cases where the local time zone is
 *	not determinable, using the C 'localtime' function to do it.
 *
 * Results:
 *	Returns a standard Tcl result.
 *
 * Side effects:
 *	On success, fills fields->tzName, fields->tzOffset and
 *	fields->localSeconds.  On failure, places an error message in
 *	the interpreter result.
 *
 *----------------------------------------------------------------------
 */
 
static int
ConvertUTCToLocalUsingC(
    Tcl_Interp* interp,		/* Tcl interpreter */
    TclDateFields* fields,	/* Time to convert, with 'seconds' filled in */
    int changeover		/* Julian Day of the Gregorian transition */
) {

    time_t tock;
    struct tm* timeVal;		/* Time after conversion */
    int diff;			/* Time zone diff local-Greenwich */
    char buffer[8];		/* Buffer for time zone name */

    /* Use 'localtime' to determine local year, month, day, time of day. */

    tock = (time_t) fields->seconds;
    if ((Tcl_WideInt) tock != fields->seconds) {
	Tcl_AppendResult(interp,
			 "number too large to represent as a Posix time",
			 NULL);
	Tcl_SetErrorCode(interp, "CLOCK", "argTooLarge", NULL);
	return TCL_ERROR;
    }
    TzsetIfNecessary();
    timeVal = ThreadSafeLocalTime(&tock);
    if (timeVal == NULL) {
	Tcl_AppendResult(interp,
			 "localtime failed (clock value may be too ",
			 "large/small to represent)", NULL);
	Tcl_SetErrorCode(interp, "CLOCK", "localtimeFailed", NULL);
	return TCL_ERROR;
    }

    /* Fill in the date in 'fields' and use it to derive Julian Day */

    fields->era = CE;
    fields->year = timeVal->tm_year + 1900;
    fields->month = timeVal->tm_mon + 1;
    fields->dayOfMonth = timeVal->tm_mday;
    GetJulianDayFromEraYearMonthDay(fields, changeover);

    /* Convert that value to seconds */
    
    fields->localSeconds = (((fields->julianDay * (Tcl_WideInt) 24
			      + timeVal->tm_hour) * 60
			     + timeVal->tm_min) * 60
			    + timeVal->tm_sec) - JULIAN_SEC_POSIX_EPOCH;
    
    /* Determine a time zone offset and name; just use +hhmm for the name */

    diff = (int) (fields->localSeconds - fields->seconds);
    fields->tzOffset = diff;
    if (diff < 0) {
	*buffer = '-';
	diff = -diff;
    } else {
	*buffer = '+';
    }
    sprintf(buffer+1, "%02d", diff / 3600);
    diff %= 3600;
    sprintf(buffer+3, "%02d", diff / 60);
    diff %= 60;
    if (diff > 0) {
	sprintf(buffer+5, "%02d", diff);
    }
    fields->tzName = Tcl_NewStringObj(buffer, -1);
    Tcl_IncrRefCount(fields->tzName);
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * LookupLastTransition --
 *
 *	Given a UTC time and a tzdata array, looks up the last
 *	transition on or before the given time.
 *
 * Results:
 *	Returns a pointer to the row, or NULL if an error occurs.
 *
 *----------------------------------------------------------------------
 */

static Tcl_Obj*
LookupLastTransition(
    Tcl_Interp* interp,		/* Interpreter for error messages */
    Tcl_WideInt tick,		/* Time from the epoch */
    int rowc,			/* Number of rows of tzdata */
    Tcl_Obj *CONST * rowv)	/* Rows in tzdata */
{
    int l;
    int u;
    Tcl_Obj* compObj;
    Tcl_WideInt compVal;

    /* Examine the first row to make sure we're in bounds */

    if (Tcl_ListObjIndex(interp, rowv[0], 0, &compObj) != TCL_OK
	|| Tcl_GetWideIntFromObj(interp, compObj, &compVal) != TCL_OK) {
	return NULL;
    }
    /* 
     * Bizarre case - first row doesn't begin at MIN_WIDE_INT.
     * Return it anyway. 
     */
    if (tick < compVal) {
	return rowv[0];
    }

    /* 
     * Binary-search to find the transition.
     */

    l = 0;
    u = rowc-1;
    while (l < u) {
	int m = (l + u + 1) / 2;
	if (Tcl_ListObjIndex(interp, rowv[m], 0, &compObj) != TCL_OK
	    || Tcl_GetWideIntFromObj(interp, compObj, &compVal) != TCL_OK) {
	    return NULL;
	}
	if (tick >= compVal) {
	    l = m;
	} else {
	    u = m-1;
	}
    }
    return rowv[l];
    
}

/*
 *----------------------------------------------------------------------
 *
 * GetYearWeekDay --
 *
 *	Given a date with Julian Calendar Day, compute the year, week,
 *	and day in the ISO8601 calendar.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Stores 'iso8601Year', 'iso8601Week' and 'dayOfWeek' in
 *	the date fields.
 *
 *----------------------------------------------------------------------
 */

static void
GetYearWeekDay(
    TclDateFields* fields,	/* Date to convert, must have 'julianDay' */
    int changeover		/* Julian Day Number of the Gregorian
				 * transition */
) {
    TclDateFields temp;
    int dayOfFiscalYear;

    /* 
     * Find the given date, minus three days, plus one year.  That date's
     * iso8601 year is an upper bound on the ISO8601 year of the given date.
     */

    temp.julianDay = fields->julianDay - 3;
    GetGregorianEraYearDay(&temp, changeover);
    if (temp.era == BCE) {
	temp.iso8601Year = temp.year - 1;
    } else {
	temp.iso8601Year = temp.year + 1;
    }
    temp.iso8601Week = 1;
    temp.dayOfWeek = 1;
    GetJulianDayFromEraYearWeekDay(&temp, changeover);

    /* 
     * temp.julianDay is now the start of an ISO8601 year, either the
     * one corresponding to the given date, or the one after. If we guessed
     * high, move one year earlier
     */

    if (fields->julianDay < temp.julianDay) {
	if (temp.era == BCE) {
	    temp.iso8601Year += 1;
	} else {
	    temp.iso8601Year -= 1;
	}
	GetJulianDayFromEraYearWeekDay(&temp, changeover);
    }

    fields->iso8601Year = temp.iso8601Year;
    dayOfFiscalYear = fields->julianDay - temp.julianDay;
    fields->iso8601Week = (dayOfFiscalYear / 7) + 1;
    fields->dayOfWeek = (dayOfFiscalYear + 1) % 7;
    if (fields->dayOfWeek < 1) {
	fields->dayOfWeek += 7;
    }
}

/*
 *----------------------------------------------------------------------
 *
 * GetGregorianEraYearDay --
 *
 *	Given a Julian Day Number, extracts the year and day of the
 *	year and puts them into TclDateFields, along with the era
 *	(BCE or CE) and a flag indicating whether the date is Gregorian
 *	or Julian.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Stores 'era', 'gregorian', 'year', and 'dayOfYear'.
 *
 *----------------------------------------------------------------------
 */

static void
GetGregorianEraYearDay(
    TclDateFields* fields,	/* Date fields containing 'julianDay' */
    int changeover		/* Gregorian transition date */
) {
    int jday = fields->julianDay;
    int day;
    int year;
    int n;

    if (jday >= changeover) {

        /* Gregorian calendar */

	fields->gregorian = 1;
	year = 1;

	/* 
	 * n = Number of 400-year cycles since 1 January, 1 CE in the
	 * proleptic Gregorian calendar.  day = remaining days.
	 */

	day = jday - JDAY_1_JAN_1_CE_GREGORIAN;
	n = day / FOUR_CENTURIES;
	day %= FOUR_CENTURIES;
	year += 400 * n;

	/*
	 * n = number of centuries since the start of (year);
	 * day = remaining days
	 */

	n = day / ONE_CENTURY_GREGORIAN;
	day %= ONE_CENTURY_GREGORIAN;
	if (n > 3) {
	    /* 31 December in the last year of a 400-year cycle */
	    n = 3;
	    day += ONE_CENTURY_GREGORIAN;
	}
	year += 100 * n;

    } else {

	/* Julian calendar */

	fields->gregorian = 0;
	year = 1;
	day = jday - JDAY_1_JAN_1_CE_JULIAN;

    }

    /* n = number of 4-year cycles; days = remaining days */

    n = day / FOUR_YEARS;
    day %= 1461;
    year += 4 * n;

    /* n = number of years; days = remaining days */

    n = day / ONE_YEAR;
    day %= ONE_YEAR;
    if (n > 3) {
	/* 31 December of a leap year */
	n = 3;
	day += 365;
    }
    year += n;

    /* store era/year/day back into fields */

    if (year < 0) {
	fields->era = BCE;
	fields->year = 1 - year;
    } else {
	fields->era = CE;
	fields->year = year;
    }
    fields->dayOfYear = day + 1;

}

/*
 *----------------------------------------------------------------------
 *
 * GetMonthDay --
 *
 *	Given a date as year and day-of-year, find month and day.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Stores 'month' and 'dayOfMonth' in the 'fields' structure.
 *
 *----------------------------------------------------------------------
 */

static void
GetMonthDay(
    TclDateFields* fields	/* Date to convert */
) {
    int day = fields->dayOfYear;
    int month;
    const int* h = hath[IsGregorianLeapYear(fields)];
    for (month = 0; month < 12 && day > h[month]; ++month) {
	day -= h[month];
    }
    fields->month = month+1;
    fields->dayOfMonth = day;
}

/*
 *----------------------------------------------------------------------
 *
 * GetJulianDayFromEraYearWeekDay --
 *
 *	Given a TclDateFields structure containing era, ISO8601 year,
 *	ISO8601 week, and day of week, computes the Julian Day Number.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Stores 'julianDay' in the fields.
 *
 *----------------------------------------------------------------------
 */

static void
GetJulianDayFromEraYearWeekDay(
    TclDateFields* fields,	/* Date to convert */
    int changeover		/* Julian Day Number of the 
				 * Gregorian transition */
) {

    int firstMonday;		/* Julian day number of week 1, day 1
				 * in the given year */

    /* Find January 4 in the ISO8601 year, which will always be in week 1 */

    TclDateFields firstWeek;
    firstWeek.era = fields->era;
    firstWeek.year = fields->iso8601Year;
    firstWeek.month = 1;
    firstWeek.dayOfMonth = 4;
    GetJulianDayFromEraYearMonthDay(&firstWeek, changeover);

    /* Find Monday of week 1. */

    firstMonday = WeekdayOnOrBefore(1, firstWeek.julianDay);

    /* Advance to the given week and day */

    fields->julianDay = firstMonday + 7 * (fields->iso8601Week - 1)
	+ fields->dayOfWeek - 1;
    
}

/*
 *----------------------------------------------------------------------
 *
 * GetJulianDayFromEraYearMonthDay --
 *
 *	Given era, year, month, and dayOfMonth (in TclDateFields), and
 *	the Gregorian transition date, computes the Julian Day Number.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Stores day number in 'julianDay'
 *
 *----------------------------------------------------------------------
 */

static void
GetJulianDayFromEraYearMonthDay(
    TclDateFields* fields,	/* Date to convert */
    int changeover		/* Gregorian transition date as a Julian Day */
) {
    int year;  int ym1;
    int month; int mm1;

    if (fields->era == BCE) {
	year = 1 - fields->year;
    } else {
	year = fields->year;
    }

    /* Reduce month modulo 12 */

    month = fields->month;
    mm1 = month - 1;
    year += mm1 / 12;
    month = (mm1 % 12) + 1;
    ym1 = year - 1;
    
    /* Adjust the year after reducing the month */

    fields->gregorian = 1;
    if (year < 1) {
	fields->era = BCE;
	fields->year = 1-year;
    } else {
	fields->era = CE;
	fields->year = year;
    }

    /* Try an initial conversion in the Gregorian calendar */

    fields->julianDay = JDAY_1_JAN_1_CE_GREGORIAN - 1
	+ fields->dayOfMonth
	+ daysInPriorMonths[IsGregorianLeapYear(fields)][month - 1]
	+ (ONE_YEAR * ym1)
	+ (ym1 / 4)
	- (ym1 / 100)
	+ (ym1 / 400);

    /* 
     * If the resulting date is before the Gregorian changeover, convert
     * in the Julian calendar instead.
     */

    if (fields->julianDay < changeover) {
	fields->gregorian = 0;
	fields->julianDay = JDAY_1_JAN_1_CE_JULIAN - 1
	    + fields->dayOfMonth
	    + daysInPriorMonths[year%4 == 0][month - 1]
	    + (365 * ym1)
	    + (ym1 / 4);
    }

}

/*
 *----------------------------------------------------------------------
 *
 * IsGregorianLeapYear --
 *
 *	Tests whether a given year is a leap year, in either Julian
 *	or Gregorian calendar.
 *
 * Results:
 *	Returns 1 for a leap year, 0 otherwise.
 *
 *----------------------------------------------------------------------
 */

static int
IsGregorianLeapYear(
    TclDateFields* fields	/* Date to test */
) {
    int year;
    if (fields->era == BCE) {
	year = 1 - fields->year;
    } else {
	year = fields->year;
    }
    if (year%4 != 0) {
	return 0;
    } else if (!(fields->gregorian)) {
	return 1;
    } else if (year%400 == 0) {
	return 1;
    } else if (year%100 == 0) {
	return 0;
    } else {
	return 1;
    }
}

/*
 *----------------------------------------------------------------------
 *
 * WeekdayOnOrBefore --
 *
 *	Finds the Julian Day Number of a given day of the week that
 *	falls on or before a given date, expressed as Julian Day Number.
 *
 * Results:
 *	Returns the Julian Day Number
 *
 *----------------------------------------------------------------------
 */

static int
WeekdayOnOrBefore(
    int dayOfWeek,		/* Day of week; Sunday == 0 or 7 */
    int julianDay		/* Reference date */
) {
    int k = (dayOfWeek + 6) % 7;
    return julianDay - ((julianDay - k) % 7);
}

/*
 *----------------------------------------------------------------------
 *
 * ClockGetenvObjCmd --
 *
 *	Tcl command that reads an environment variable from the system
 *
 * Usage:
 *	::tcl::clock::getEnv NAME
 *
 * Parameters:
 *	NAME - Name of the environment variable desired
 *
 * Results:
 *	Returns a standard Tcl result.  Returns an error if the
 *	variable does not exist, with a message left in the interpreter.
 *	Returns TCL_OK and the value of the variable if the variable
 *	does exist,
 *
 *----------------------------------------------------------------------
 */

int
ClockGetenvObjCmd(
    ClientData clientData,
    Tcl_Interp* interp,
    int objc,
    Tcl_Obj *CONST objv[])
{

    CONST char* varName;
    CONST char* varValue;

    if (objc != 2) {
	Tcl_WrongNumArgs(interp, 1, objv, "name");
	return TCL_ERROR;
    }
    varName = Tcl_GetStringFromObj(objv[1], NULL);
    varValue = getenv(varName);
    if (varValue == NULL) {
	Tcl_SetObjResult(interp,
		Tcl_NewStringObj("variable not found", -1));
	return TCL_ERROR;
    } else {
	Tcl_SetObjResult(interp, Tcl_NewStringObj(varValue, -1));
	return TCL_OK;
    }
}

/*
 *----------------------------------------------------------------------
 *
 * ThreadSafeLocalTime --
 *
 *	Wrapper around the 'localtime' library function to make it thread
 *	safe.
 *
 * Results:
 *	Returns a pointer to a 'struct tm' in thread-specific data.
 *
 * Side effects:
 *	Invokes localtime or localtime_r as appropriate.
 *
 *----------------------------------------------------------------------
 */

static struct tm *
ThreadSafeLocalTime(
    CONST time_t *timePtr)	/* Pointer to the number of seconds since the
				 * local system's epoch */
{
    /*
     * Get a thread-local buffer to hold the returned time.
     */

    struct tm *tmPtr = (struct tm *)
	    Tcl_GetThreadData(&tmKey, (int) sizeof(struct tm));
#ifdef HAVE_LOCALTIME_R
    localtime_r(timePtr, tmPtr);
#else
    struct tm *sysTmPtr;

    Tcl_MutexLock(&clockMutex);
    sysTmPtr = localtime(timePtr);
    if (sysTmPtr == NULL) {
	Tcl_MutexUnlock(&clockMutex);
	return NULL;
    } else {
	memcpy((VOID *) tmPtr, (VOID *) localtime(timePtr), sizeof(struct tm));
	Tcl_MutexUnlock(&clockMutex);
    }
#endif
    return tmPtr;
}

/*----------------------------------------------------------------------
 *
 * ClockClicksObjCmd --
 *
 *	Returns a high-resolution counter.
 *
 * Results:
 *	Returns a standard Tcl result.
 *
 * Side effects:
 *	None.
 *
 * This function implements the 'clock clicks' Tcl command. Refer to the user
 * documentation for details on what it does.
 *
 *----------------------------------------------------------------------
 */

int
ClockClicksObjCmd(
    ClientData clientData,	/* Client data is unused */
    Tcl_Interp* interp,		/* Tcl interpreter */
    int objc,			/* Parameter count */
    Tcl_Obj* CONST* objv)	/* Parameter values */
{
    static CONST char *clicksSwitches[] = {
	"-milliseconds", "-microseconds", NULL
    };
    enum ClicksSwitch {
	CLICKS_MILLIS,   CLICKS_MICROS,   CLICKS_NATIVE
    };
    int index = CLICKS_NATIVE;
    Tcl_Time now;

    switch (objc) {
    case 1:
	break;
    case 2:
	if (Tcl_GetIndexFromObj(interp, objv[1], clicksSwitches, "option", 0,
		&index) != TCL_OK) {
	    return TCL_ERROR;
	}
	break;
    default:
	Tcl_WrongNumArgs(interp, 1, objv, "?option?");
	return TCL_ERROR;
    }

    switch (index) {
    case CLICKS_MILLIS:
	Tcl_GetTime(&now);
	Tcl_SetObjResult(interp, Tcl_NewWideIntObj( (Tcl_WideInt)
		now.sec * 1000 + now.usec / 1000 ) );
	break;
    case CLICKS_NATIVE:
	Tcl_SetObjResult(interp, Tcl_NewWideIntObj( (Tcl_WideInt)
		TclpGetClicks()));
	break;
    case CLICKS_MICROS:
	Tcl_GetTime(&now);
	Tcl_SetObjResult(interp, Tcl_NewWideIntObj(
		((Tcl_WideInt) now.sec * 1000000) + now.usec));
	break;
    }

    return TCL_OK;
}

/*----------------------------------------------------------------------
 *
 * ClockMillisecondsObjCmd -
 *
 *	Returns a count of milliseconds since the epoch.
 *
 * Results:
 *	Returns a standard Tcl result.
 *
 * Side effects:
 *	None.
 *
 * This function implements the 'clock milliseconds' Tcl command. Refer to the
 * user documentation for details on what it does.
 *
 *----------------------------------------------------------------------
 */

int
ClockMillisecondsObjCmd(
    ClientData clientData,	/* Client data is unused */
    Tcl_Interp* interp,		/* Tcl interpreter */
    int objc,			/* Parameter count */
    Tcl_Obj* CONST* objv)	/* Parameter values */
{
    Tcl_Time now;

    if (objc != 1) {
	Tcl_WrongNumArgs(interp, 1, objv, NULL);
	return TCL_ERROR;
    }
    Tcl_GetTime(&now);
    Tcl_SetObjResult(interp, Tcl_NewWideIntObj( (Tcl_WideInt)
	    now.sec * 1000 + now.usec / 1000));
    return TCL_OK;
}

/*----------------------------------------------------------------------
 *
 * ClockMicrosecondsObjCmd -
 *
 *	Returns a count of microseconds since the epoch.
 *
 * Results:
 *	Returns a standard Tcl result.
 *
 * Side effects:
 *	None.
 *
 * This function implements the 'clock microseconds' Tcl command. Refer to the
 * user documentation for details on what it does.
 *
 *----------------------------------------------------------------------
 */

int
ClockMicrosecondsObjCmd(
    ClientData clientData,	/* Client data is unused */
    Tcl_Interp* interp,		/* Tcl interpreter */
    int objc,			/* Parameter count */
    Tcl_Obj* CONST* objv)	/* Parameter values */
{
    Tcl_Time now;

    if (objc != 1) {
	Tcl_WrongNumArgs(interp, 1, objv, NULL);
	return TCL_ERROR;
    }
    Tcl_GetTime(&now);
    Tcl_SetObjResult(interp, Tcl_NewWideIntObj(
	    ((Tcl_WideInt) now.sec * 1000000) + now.usec));
    return TCL_OK;
}

/*----------------------------------------------------------------------
 *
 * ClockSecondsObjCmd -
 *
 *	Returns a count of microseconds since the epoch.
 *
 * Results:
 *	Returns a standard Tcl result.
 *
 * Side effects:
 *	None.
 *
 * This function implements the 'clock seconds' Tcl command. Refer to the user
 * documentation for details on what it does.
 *
 *----------------------------------------------------------------------
 */

int
ClockSecondsObjCmd(
    ClientData clientData,	/* Client data is unused */
    Tcl_Interp* interp,		/* Tcl interpreter */
    int objc,			/* Parameter count */
    Tcl_Obj* CONST* objv)	/* Parameter values */
{
    Tcl_Time now;

    if (objc != 1) {
	Tcl_WrongNumArgs(interp, 1, objv, NULL);
	return TCL_ERROR;
    }
    Tcl_GetTime(&now);
    Tcl_SetObjResult(interp, Tcl_NewWideIntObj((Tcl_WideInt) now.sec));
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * TzsetIfNecessary --
 *
 *	Calls the tzset() library function if the contents of the TZ
 *	environment variable has changed.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Calls tzset.
 *
 *----------------------------------------------------------------------
 */

static void
TzsetIfNecessary(void)
{
    static char* tzWas = NULL;	/* Previous value of TZ, protected by
				 * clockMutex. */
    CONST char* tzIsNow;	/* Current value of TZ */

    Tcl_MutexLock(&clockMutex);
    tzIsNow = getenv("TZ");
    if (tzIsNow != NULL && (tzWas == NULL || strcmp(tzIsNow, tzWas) != 0)) {
	tzset();
	if (tzWas != NULL) {
	    ckfree(tzWas);
	}
	tzWas = ckalloc(strlen(tzIsNow) + 1);
	strcpy(tzWas, tzIsNow);
    } else if (tzIsNow == NULL && tzWas != NULL) {
	tzset();
	ckfree(tzWas);
	tzWas = NULL;
    }
    Tcl_MutexUnlock(&clockMutex);
}

/*
 *----------------------------------------------------------------------
 *
 * ClockDeleteCmdProc --
 *
 *	Remove a reference to the clock client data, and clean up memory
 *	when it's all gone.
 *
 * Results:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static void
ClockDeleteCmdProc(ClientData clientData)
				/* Opaque pointer to the client data */
{
    ClockClientData *data = (ClockClientData*) clientData;
    int i;
    --(data->refCount);
    if (data->refCount == 0) {
	for (i = 0; i < LIT__END; ++i) {
	    Tcl_DecrRefCount(data->literals[i]);
	}
	ckfree((char*) (data->literals));
	ckfree((char*) data);
    }
}

/*
 * Local Variables:
 * mode: c
 * c-basic-offset: 4
 * fill-column: 78
 * End:
 */