summaryrefslogtreecommitdiffstats
path: root/generic/tkbltVector.C
blob: e6262ec5eca426fe76ea42932c8b95526bca2f09 (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
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
/*
 * Smithsonian Astrophysical Observatory, Cambridge, MA, USA
 * This code has been modified under the terms listed below and is made
 * available under the same terms.
 */

/*
 *	Copyright 1995-2004 George A Howlett.
 *
 *	Permission is hereby granted, free of charge, to any person obtaining
 *	a copy of this software and associated documentation files (the
 *	"Software"), to deal in the Software without restriction, including
 *	without limitation the rights to use, copy, modify, merge, publish,
 *	distribute, sublicense, and/or sell copies of the Software, and to
 *	permit persons to whom the Software is furnished to do so, subject to
 *	the following conditions:
 *
 *	The above copyright notice and this permission notice shall be
 *	included in all copies or substantial portions of the Software.
 *
 *	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 *	EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 *	MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 *	NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 *	LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 *	OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 *	WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

/*
 * TODO:
 *	o Add H. Kirsch's vector binary read operation
 *		x binread file0
 *		x binread -file file0
 *
 *	o Add ASCII/binary file reader
 *		x read fileName
 *
 *	o Allow Tcl-based client notifications.
 *		vector x
 *		x notify call Display
 *		x notify delete Display
 *		x notify reorder #1 #2
 */

#include <float.h>
#include <time.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <ctype.h>

#include <cmath>

#include "tkbltVecInt.h"
#include "tkbltNsUtil.h"
#include "tkbltSwitch.h"
#include "tkbltOp.h"

using namespace Blt;

#define DEF_ARRAY_SIZE		64
#define TRACE_ALL  (TCL_TRACE_WRITES | TCL_TRACE_READS | TCL_TRACE_UNSETS)


#define VECTOR_CHAR(c)	((isalnum((unsigned char)(c))) ||		\
			 (c == '_') || (c == ':') || (c == '@') || (c == '.'))

/*
 * VectorClient --
 *
 *	A vector can be shared by several clients.  Each client allocates this
 *	structure that acts as its key for using the vector.  Clients can also
 *	designate a callback routine that is executed whenever the vector is
 *	updated or destroyed.
 *
 */
typedef struct {
  unsigned int magic;		/* Magic value designating whether this really
				 * is a vector token or not */
  Vector* serverPtr;		/* Pointer to the master record of the vector.
				 * If NULL, indicates that the vector has been
				 * destroyed but as of yet, this client hasn't
				 * recognized it. */
  Blt_VectorChangedProc *proc;/* Routine to call when the contents of the
			       * vector change or the vector is deleted. */
  ClientData clientData;	/* Data passed whenever the vector change
				 * procedure is called. */
  ChainLink* link;		/* Used to quickly remove this entry from its
				 * server's client chain. */
} VectorClient;

static Tcl_CmdDeleteProc VectorInstDeleteProc;
extern Tcl_ObjCmdProc VectorCmd;
static Tcl_InterpDeleteProc VectorInterpDeleteProc;

typedef struct {
  char *varName;		/* Requested variable name. */
  char *cmdName;		/* Requested command name. */
  int flush;			/* Flush */
  int watchUnset;		/* Watch when variable is unset. */
} CreateSwitches;

static Blt_SwitchSpec createSwitches[] = 
  {
    {BLT_SWITCH_STRING, "-variable", "varName",
     Tk_Offset(CreateSwitches, varName), BLT_SWITCH_NULL_OK},
    {BLT_SWITCH_STRING, "-command", "command",
     Tk_Offset(CreateSwitches, cmdName), BLT_SWITCH_NULL_OK},
    {BLT_SWITCH_BOOLEAN, "-watchunset", "bool",
     Tk_Offset(CreateSwitches, watchUnset), 0},
    {BLT_SWITCH_BOOLEAN, "-flush", "bool",
     Tk_Offset(CreateSwitches, flush), 0},
    {BLT_SWITCH_END}
  };

typedef int (VectorCmdProc)(Vector* vecObjPtr, Tcl_Interp* interp, 
			    int objc, Tcl_Obj* const objv[]);

static char stringRep[200];

const char *Blt::Itoa(int value)
{
  snprintf(stringRep, 200, "%d", value);
  return stringRep;
}

static char* Blt_Strdup(const char *string)
{
  size_t size = strlen(string) + 1;
  char* ptr = (char*)malloc(size * sizeof(char));
  if (ptr != NULL)
    strcpy(ptr, string);

  return ptr;
}

static Vector* FindVectorInNamespace(VectorInterpData *dataPtr,	
				     Blt_ObjectName *objNamePtr)
{
  Tcl_DString dString;
  const char* name = MakeQualifiedName(objNamePtr, &dString);
  Tcl_HashEntry* hPtr = Tcl_FindHashEntry(&dataPtr->vectorTable, name);
  Tcl_DStringFree(&dString);
  if (hPtr != NULL)
    return (Vector*)Tcl_GetHashValue(hPtr);

  return NULL;
}

static Vector* GetVectorObject(VectorInterpData *dataPtr, const char *name,
			       int flags)
{
  Tcl_Interp* interp = dataPtr->interp;
  Blt_ObjectName objName;
  if (!ParseObjectName(interp, name, &objName, BLT_NO_ERROR_MSG | BLT_NO_DEFAULT_NS))
    return NULL;

  Vector* vPtr = NULL;
  if (objName.nsPtr != NULL)
    vPtr = FindVectorInNamespace(dataPtr, &objName);
  else {
    if (flags & NS_SEARCH_CURRENT) {
      objName.nsPtr = Tcl_GetCurrentNamespace(interp);
      vPtr = FindVectorInNamespace(dataPtr, &objName);
    }
    if ((vPtr == NULL) && (flags & NS_SEARCH_GLOBAL)) {
      objName.nsPtr = Tcl_GetGlobalNamespace(interp);
      vPtr = FindVectorInNamespace(dataPtr, &objName);
    }
  }

  return vPtr;
}

void Blt::Vec_UpdateRange(Vector* vPtr)
{
  double* vp = vPtr->valueArr + vPtr->first;
  double* vend = vPtr->valueArr + vPtr->last;
  double min = *vp;
  double max = *vp++;
  for (/* empty */; vp <= vend; vp++) {
    if (min > *vp)
      min = *vp; 
    else if (max < *vp)
      max = *vp; 
  } 
  vPtr->min = min;
  vPtr->max = max;
  vPtr->notifyFlags &= ~UPDATE_RANGE;
}

int Blt::Vec_GetIndex(Tcl_Interp* interp, Vector* vPtr, const char *string,
		     int *indexPtr, int flags, Blt_VectorIndexProc **procPtrPtr)
{
  int value;
  char c = string[0];

  // Treat the index "end" like a numeric index
  if ((c == 'e') && (strcmp(string, "end") == 0)) {
    if (vPtr->length < 1) {
      if (interp != NULL) {
	Tcl_AppendResult(interp, "bad index \"end\": vector is empty", 
			 (char *)NULL);
      }
      return TCL_ERROR;
    }
    *indexPtr = vPtr->length - 1;
    return TCL_OK;
  } else if ((c == '+') && (strcmp(string, "++end") == 0)) {
    *indexPtr = vPtr->length;
    return TCL_OK;
  }
  if (procPtrPtr != NULL) {
    Tcl_HashEntry *hPtr;

    hPtr = Tcl_FindHashEntry(&vPtr->dataPtr->indexProcTable, string);
    if (hPtr != NULL) {
      *indexPtr = SPECIAL_INDEX;
      *procPtrPtr = (Blt_VectorIndexProc*)Tcl_GetHashValue(hPtr);
      return TCL_OK;
    }
  }
  if (Tcl_GetInt(interp, (char *)string, &value) != TCL_OK) {
    long int lvalue;
    /*   
     * Unlike Tcl_GetInt, Tcl_ExprLong needs a valid interpreter, but the
     * interp passed in may be NULL.  So we have to use vPtr->interp and
     * then reset the result.
     */
    if (Tcl_ExprLong(vPtr->interp, (char *)string, &lvalue) != TCL_OK) {
      Tcl_ResetResult(vPtr->interp);
      if (interp != NULL) {
	Tcl_AppendResult(interp, "bad index \"", string, "\"", 
			 (char *)NULL);
      }
      return TCL_ERROR;
    }
    value = (int)lvalue;
  }
  /*
   * Correct the index by the current value of the offset. This makes all
   * the numeric indices non-negative, which is how we distinguish the
   * special non-numeric indices.
   */
  value -= vPtr->offset;

  if ((value < 0) || ((flags & INDEX_CHECK) && (value >= vPtr->length))) {
    if (interp != NULL) {
      Tcl_AppendResult(interp, "index \"", string, "\" is out of range", 
		       (char *)NULL);
    }
    return TCL_ERROR;
  }
  *indexPtr = (int)value;
  return TCL_OK;
}

int Blt::Vec_GetIndexRange(Tcl_Interp* interp, Vector* vPtr, const char *string,
			   int flags, Blt_VectorIndexProc** procPtrPtr)
{
  int ielem;
  char* colon = NULL;
  if (flags & INDEX_COLON)
    colon = (char*)strchr(string, ':');

  if (colon != NULL) {
    if (string == colon) {
      vPtr->first = 0;	/* Default to the first index */
    }
    else {
      int result;

      *colon = '\0';
      result = Vec_GetIndex(interp, vPtr, string, &ielem, flags,
				(Blt_VectorIndexProc **) NULL);
      *colon = ':';
      if (result != TCL_OK) {
	return TCL_ERROR;
      }
      vPtr->first = ielem;
    }
    if (*(colon + 1) == '\0') {
      /* Default to the last index */
      vPtr->last = (vPtr->length > 0) ? vPtr->length - 1 : 0;
    } else {
      if (Vec_GetIndex(interp, vPtr, colon + 1, &ielem, flags,
			   (Blt_VectorIndexProc **) NULL) != TCL_OK) {
	return TCL_ERROR;
      }
      vPtr->last = ielem;
    }
    if (vPtr->first > vPtr->last) {
      if (interp != NULL) {
	Tcl_AppendResult(interp, "bad range \"", string,
			 "\" (first > last)", (char *)NULL);
      }
      return TCL_ERROR;
    }
  } else {
    if (Vec_GetIndex(interp, vPtr, string, &ielem, flags, 
			 procPtrPtr) != TCL_OK) {
      return TCL_ERROR;
    }
    vPtr->last = vPtr->first = ielem;
  }
  return TCL_OK;
}

Vector* Blt::Vec_ParseElement(Tcl_Interp* interp, VectorInterpData *dataPtr,
			     const char* start, const char** endPtr, int flags)
{
  char* p = (char*)start;
  // Find the end of the vector name
  while (VECTOR_CHAR(*p)) {
    p++;
  }
  char saved = *p;
  *p = '\0';

  Vector* vPtr = GetVectorObject(dataPtr, start, flags);
  if (vPtr == NULL) {
    if (interp != NULL) {
      Tcl_AppendResult(interp, "can't find vector \"", start, "\"", 
		       (char *)NULL);
    }
    *p = saved;
    return NULL;
  }
  *p = saved;
  vPtr->first = 0;
  vPtr->last = vPtr->length - 1;
  if (*p == '(') {
    int count, result;

    start = p + 1;
    p++;

    /* Find the matching right parenthesis */
    count = 1;
    while (*p != '\0') {
      if (*p == ')') {
	count--;
	if (count == 0) {
	  break;
	}
      } else if (*p == '(') {
	count++;
      }
      p++;
    }
    if (count > 0) {
      if (interp != NULL) {
	Tcl_AppendResult(interp, "unbalanced parentheses \"", start, 
			 "\"", (char *)NULL);
      }
      return NULL;
    }
    *p = '\0';
    result = Vec_GetIndexRange(interp, vPtr, start, (INDEX_COLON | INDEX_CHECK), (Blt_VectorIndexProc **) NULL);
    *p = ')';
    if (result != TCL_OK) {
      return NULL;
    }
    p++;
  }
  if (endPtr != NULL) {
    *endPtr = p;
  }
  return vPtr;
}

void Blt_Vec_NotifyClients(ClientData clientData)
{
  Vector* vPtr = (Vector*)clientData;
  ChainLink *link, *next;
  Blt_VectorNotify notify;

  notify = (vPtr->notifyFlags & NOTIFY_DESTROYED)
    ? BLT_VECTOR_NOTIFY_DESTROY : BLT_VECTOR_NOTIFY_UPDATE;
  vPtr->notifyFlags &= ~(NOTIFY_UPDATED | NOTIFY_DESTROYED | NOTIFY_PENDING);
  for (link = Chain_FirstLink(vPtr->chain); link; link = next) {
    next = Chain_NextLink(link);
    VectorClient *clientPtr = (VectorClient*)Chain_GetValue(link);
    if ((clientPtr->proc != NULL) && (clientPtr->serverPtr != NULL)) {
      (*clientPtr->proc) (vPtr->interp, clientPtr->clientData, notify);
    }
  }

  // Some clients may not handle the "destroy" callback properly (they
  // should call Blt_FreeVectorId to release the client identifier), so mark
  // any remaining clients to indicate that vector's server has gone away.
  if (notify == BLT_VECTOR_NOTIFY_DESTROY) {
    for (link = Chain_FirstLink(vPtr->chain); link; 
	 link = Chain_NextLink(link)) {
      VectorClient *clientPtr = (VectorClient*)Chain_GetValue(link);
      clientPtr->serverPtr = NULL;
    }
  }
}

void Blt::Vec_UpdateClients(Vector* vPtr)
{
  vPtr->dirty++;
  vPtr->max = vPtr->min = NAN;
  if (vPtr->notifyFlags & NOTIFY_NEVER) {
    return;
  }
  vPtr->notifyFlags |= NOTIFY_UPDATED;
  if (vPtr->notifyFlags & NOTIFY_ALWAYS) {
    Blt_Vec_NotifyClients(vPtr);
    return;
  }
  if (!(vPtr->notifyFlags & NOTIFY_PENDING)) {
    vPtr->notifyFlags |= NOTIFY_PENDING;
    Tcl_DoWhenIdle(Blt_Vec_NotifyClients, vPtr);
  }
}

void Blt::Vec_FlushCache(Vector* vPtr)
{
  Tcl_Interp* interp = vPtr->interp;

  if (vPtr->arrayName == NULL)
    return;

  /* Turn off the trace temporarily so that we can unset all the
   * elements in the array.  */

  Tcl_UntraceVar2(interp, vPtr->arrayName, (char *)NULL,
		  TRACE_ALL | vPtr->varFlags, Vec_VarTrace, vPtr);

  /* Clear all the element entries from the entire array */
  Tcl_UnsetVar2(interp, vPtr->arrayName, (char *)NULL, vPtr->varFlags);

  /* Restore the "end" index by default and the trace on the entire array */
  Tcl_SetVar2(interp, vPtr->arrayName, "end", "", vPtr->varFlags);
  Tcl_TraceVar2(interp, vPtr->arrayName, (char *)NULL,
		TRACE_ALL | vPtr->varFlags, Vec_VarTrace, vPtr);
}

int Blt::Vec_LookupName(VectorInterpData *dataPtr, const char *vecName,
		       Vector** vPtrPtr)
{

  const char *endPtr;
  Vector* vPtr = Vec_ParseElement(dataPtr->interp, dataPtr, vecName, &endPtr, NS_SEARCH_BOTH);
  if (vPtr == NULL)
    return TCL_ERROR;

  if (*endPtr != '\0') {
    Tcl_AppendResult(dataPtr->interp, 
		     "extra characters after vector name", (char *)NULL);
    return TCL_ERROR;
  }

  *vPtrPtr = vPtr;
  return TCL_OK;
}

double Blt::Vec_Min(Vector* vecObjPtr)
{
  double* vp = vecObjPtr->valueArr + vecObjPtr->first;
  double* vend = vecObjPtr->valueArr + vecObjPtr->last;
  double min = *vp++;
  for (/* empty */; vp <= vend; vp++) {
    if (min > *vp)
      min = *vp; 
  } 
  vecObjPtr->min = min;
  return vecObjPtr->min;
}

double Blt::Vec_Max(Vector* vecObjPtr)
{
  double max = NAN;
  double* vp = vecObjPtr->valueArr + vecObjPtr->first;
  double* vend = vecObjPtr->valueArr + vecObjPtr->last;
  max = *vp++;
  for (/* empty */; vp <= vend; vp++) {
    if (max < *vp)
      max = *vp; 
  } 
  vecObjPtr->max = max;
  return vecObjPtr->max;
}

static void DeleteCommand(Vector* vPtr)
{
  Tcl_Interp* interp = vPtr->interp;
  char *qualName;
  Tcl_CmdInfo cmdInfo;
  Tcl_DString dString;
  Blt_ObjectName objName;

  Tcl_DStringInit(&dString);
  objName.name = Tcl_GetCommandName(interp, vPtr->cmdToken);
  objName.nsPtr = GetCommandNamespace(vPtr->cmdToken);
  qualName = MakeQualifiedName(&objName, &dString);
  if (Tcl_GetCommandInfo(interp, qualName, &cmdInfo)) {
    // Disable the callback before deleting the TCL command
    cmdInfo.deleteProc = NULL;	
    Tcl_SetCommandInfo(interp, qualName, &cmdInfo);
    Tcl_DeleteCommandFromToken(interp, vPtr->cmdToken);
  }
  Tcl_DStringFree(&dString);
  vPtr->cmdToken = 0;
}

static void UnmapVariable(Vector* vPtr)
{
  Tcl_Interp* interp = vPtr->interp;

  // Unset the entire array
  Tcl_UntraceVar2(interp, vPtr->arrayName, (char *)NULL,
		  (TRACE_ALL | vPtr->varFlags), Vec_VarTrace, vPtr);
  Tcl_UnsetVar2(interp, vPtr->arrayName, (char *)NULL, vPtr->varFlags);

  if (vPtr->arrayName != NULL) {
    free((void*)(vPtr->arrayName));
    vPtr->arrayName = NULL;
  }
}

int Blt::Vec_MapVariable(Tcl_Interp* interp, Vector* vPtr, const char *path)
{
  Blt_ObjectName objName;
  char *newPath;
  const char *result;
  Tcl_DString dString;

  if (vPtr->arrayName != NULL) {
    UnmapVariable(vPtr);
  }
  if ((path == NULL) || (path[0] == '\0')) {
    return TCL_OK;		/* If the variable pathname is the empty
				 * string, simply return after removing any
				 * existing variable. */
  }
  /* Get the variable name (without the namespace qualifier). */
  if (!ParseObjectName(interp, path, &objName, BLT_NO_DEFAULT_NS)) {
    return TCL_ERROR;
  }
  if (objName.nsPtr == NULL) {
    /* 
     * If there was no namespace qualifier, try harder to see if the
     * variable is non-local.
     */
    objName.nsPtr = GetVariableNamespace(interp, objName.name);
  } 
  Tcl_DStringInit(&dString);
  vPtr->varFlags = 0;
  if (objName.nsPtr != NULL) {	/* Global or namespace variable. */
    newPath = MakeQualifiedName(&objName, &dString);
    vPtr->varFlags |= (TCL_GLOBAL_ONLY);
  } else {			/* Local variable. */
    newPath = (char *)objName.name;
  }

  /*
   * To play it safe, delete the variable first.  This has the benefical
   * side-effect of unmapping the variable from another vector that may be
   * currently associated with it.
   */
  Tcl_UnsetVar2(interp, newPath, (char *)NULL, 0);

  /* 
   * Set the index "end" in the array.  This will create the variable
   * immediately so that we can check its namespace context.
   */
  result = Tcl_SetVar2(interp, newPath, "end", "", TCL_LEAVE_ERR_MSG);
  if (result == NULL) {
    Tcl_DStringFree(&dString);
    return TCL_ERROR;
  }
  /* Create a full-array trace on reads, writes, and unsets. */
  Tcl_TraceVar2(interp, newPath, (char *)NULL, TRACE_ALL, Vec_VarTrace,
		vPtr);
  vPtr->arrayName = Blt_Strdup(newPath);
  Tcl_DStringFree(&dString);
  return TCL_OK;
}

int Blt::Vec_SetSize(Tcl_Interp* interp, Vector* vPtr, int newSize)
{
  if (newSize <= 0) {
    newSize = DEF_ARRAY_SIZE;
  }
  if (newSize == vPtr->size) {
    /* Same size, use the current array. */
    return TCL_OK;
  } 
  if (vPtr->freeProc == TCL_DYNAMIC) {
    /* Old memory was dynamically allocated, so use realloc. */
    double* newArr = (double*)realloc(vPtr->valueArr, newSize * sizeof(double));
    if (newArr == NULL) {
      if (interp != NULL) {
	Tcl_AppendResult(interp, "can't reallocate ", 
			 Itoa(newSize), " elements for vector \"", 
			 vPtr->name, "\"", (char *)NULL); 
      }
      return TCL_ERROR;
    }
    vPtr->size = newSize;
    vPtr->valueArr = newArr;
    return TCL_OK;
  }

  {
    /* Old memory was created specially (static or special allocator).
     * Replace with dynamically allocated memory (malloc-ed). */

    double* newArr = (double*)calloc(newSize, sizeof(double));
    if (newArr == NULL) {
      if (interp != NULL) {
	Tcl_AppendResult(interp, "can't allocate ", 
			 Itoa(newSize), " elements for vector \"", 
			 vPtr->name, "\"", (char *)NULL); 
      }
      return TCL_ERROR;
    }
    {
      int used, wanted;
	    
      /* Copy the contents of the old memory into the new. */
      used = vPtr->length;
      wanted = newSize;
	    
      if (used > wanted) {
	used = wanted;
      }
      /* Copy any previous data */
      if (used > 0) {
	memcpy(newArr, vPtr->valueArr, used * sizeof(double));
      }
    }
	
    /* 
     * We're not using the old storage anymore, so free it if it's not
     * TCL_STATIC.  It's static because the user previously reset the
     * vector with a statically allocated array (setting freeProc to
     * TCL_STATIC).
     */
    if (vPtr->freeProc != TCL_STATIC) {
      if (vPtr->freeProc == TCL_DYNAMIC) {
	free(vPtr->valueArr);
      } else {
	(*vPtr->freeProc) ((char *)vPtr->valueArr);
      }
    }
    vPtr->freeProc = TCL_DYNAMIC; /* Set the type of the new storage */
    vPtr->valueArr = newArr;
    vPtr->size = newSize;
  }
  return TCL_OK;
}

int Blt::Vec_SetLength(Tcl_Interp* interp, Vector* vPtr, int newLength)
{
  if (vPtr->size < newLength) {
    if (Vec_SetSize(interp, vPtr, newLength) != TCL_OK) {
      return TCL_ERROR;
    }
  }
  vPtr->length = newLength;
  vPtr->first = 0;
  vPtr->last = newLength - 1;
  return TCL_OK;
}

int Blt::Vec_ChangeLength(Tcl_Interp* interp, Vector* vPtr, int newLength)
{
  if (newLength < 0) {
    newLength = 0;
  } 
  if (newLength > vPtr->size) {
    int newSize;		/* Size of array in elements */
    
    /* Compute the new size of the array.  It's a multiple of
     * DEF_ARRAY_SIZE. */
    newSize = DEF_ARRAY_SIZE;
    while (newSize < newLength) {
      newSize += newSize;
    }
    if (newSize != vPtr->size) {
      if (Vec_SetSize(interp, vPtr, newSize) != TCL_OK) {
	return TCL_ERROR;
      }
    }
  }
  vPtr->length = newLength;
  vPtr->first = 0;
  vPtr->last = newLength - 1;
  return TCL_OK;
    
}

int Blt::Vec_Reset(Vector* vPtr, double *valueArr, int length,
		  int size, Tcl_FreeProc *freeProc)
{
  if (vPtr->valueArr != valueArr) {	/* New array of values resides
					 * in different memory than
					 * the current vector.  */
    if ((valueArr == NULL) || (size == 0)) {
      /* Empty array. Set up default values */
      valueArr = (double*)malloc(sizeof(double) * DEF_ARRAY_SIZE);
      size = DEF_ARRAY_SIZE;
      if (valueArr == NULL) {
	Tcl_AppendResult(vPtr->interp, "can't allocate ", 
			 Itoa(size), " elements for vector \"", 
			 vPtr->name, "\"", (char *)NULL);
	return TCL_ERROR;
      }
      freeProc = TCL_DYNAMIC;
      length = 0;
    }
    else if (freeProc == TCL_VOLATILE) {
      /* Data is volatile. Make a copy of the value array.  */
      double* newArr = (double*)malloc(size * sizeof(double));
      if (newArr == NULL) {
	Tcl_AppendResult(vPtr->interp, "can't allocate ", 
			 Itoa(size), " elements for vector \"", 
			 vPtr->name, "\"", (char *)NULL);
	return TCL_ERROR;
      }
      memcpy((char *)newArr, (char *)valueArr, 
	     sizeof(double) * length);
      valueArr = newArr;
      freeProc = TCL_DYNAMIC;
    } 

    if (vPtr->freeProc != TCL_STATIC) {
      /* Old data was dynamically allocated. Free it before attaching
       * new data.  */
      if (vPtr->freeProc == TCL_DYNAMIC) {
	free(vPtr->valueArr);
      } else {
	(*freeProc) ((char *)vPtr->valueArr);
      }
    }
    vPtr->freeProc = freeProc;
    vPtr->valueArr = valueArr;
    vPtr->size = size;
  }

  vPtr->length = length;
  if (vPtr->flush) {
    Vec_FlushCache(vPtr);
  }
  Vec_UpdateClients(vPtr);
  return TCL_OK;
}

Vector* Blt::Vec_New(VectorInterpData *dataPtr)
{
  Vector* vPtr = (Vector*)calloc(1, sizeof(Vector));
  vPtr->valueArr = (double*)malloc(sizeof(double) * DEF_ARRAY_SIZE);
  if (vPtr->valueArr == NULL) {
    free(vPtr);
    return NULL;
  }
  vPtr->size = DEF_ARRAY_SIZE;
  vPtr->freeProc = TCL_DYNAMIC;
  vPtr->length = 0;
  vPtr->interp = dataPtr->interp;
  vPtr->hashPtr = NULL;
  vPtr->chain = new Chain();
  vPtr->flush = 0;
  vPtr->min = vPtr->max = NAN;
  vPtr->notifyFlags = NOTIFY_WHENIDLE;
  vPtr->dataPtr = dataPtr;
  return vPtr;
}

void Blt::Vec_Free(Vector* vPtr)
{
  ChainLink* link;

  if (vPtr->cmdToken != 0) {
    DeleteCommand(vPtr);
  }
  if (vPtr->arrayName != NULL) {
    UnmapVariable(vPtr);
  }
  vPtr->length = 0;

  /* Immediately notify clients that vector is going away */
  if (vPtr->notifyFlags & NOTIFY_PENDING) {
    vPtr->notifyFlags &= ~NOTIFY_PENDING;
    Tcl_CancelIdleCall(Blt_Vec_NotifyClients, vPtr);
  }
  vPtr->notifyFlags |= NOTIFY_DESTROYED;
  Blt_Vec_NotifyClients(vPtr);

  for (link = Chain_FirstLink(vPtr->chain); link; link = Chain_NextLink(link)) {
    VectorClient *clientPtr = (VectorClient*)Chain_GetValue(link);
    free(clientPtr);
  }
  delete vPtr->chain;
  if ((vPtr->valueArr != NULL) && (vPtr->freeProc != TCL_STATIC)) {
    if (vPtr->freeProc == TCL_DYNAMIC) {
      free(vPtr->valueArr);
    } else {
      (*vPtr->freeProc) ((char *)vPtr->valueArr);
    }
  }
  if (vPtr->hashPtr != NULL) {
    Tcl_DeleteHashEntry(vPtr->hashPtr);
  }
#ifdef NAMESPACE_DELETE_NOTIFY
  if (vPtr->nsPtr != NULL) {
    Blt_DestroyNsDeleteNotify(vPtr->interp, vPtr->nsPtr, vPtr);
  }
#endif /* NAMESPACE_DELETE_NOTIFY */
  free(vPtr);
}

static void VectorInstDeleteProc(ClientData clientData)
{
  Vector* vPtr = (Vector*)clientData;
  vPtr->cmdToken = 0;
  Vec_Free(vPtr);
}

Vector* Blt::Vec_Create(VectorInterpData *dataPtr, const char *vecName,
		       const char *cmdName, const char *varName, int *isNewPtr)
{
  Tcl_DString dString;
  Blt_ObjectName objName;
  char *qualName;
  Tcl_HashEntry *hPtr;
  Tcl_Interp* interp = dataPtr->interp;

  int isNew = 0;
  Vector* vPtr = NULL;

  if (!ParseObjectName(interp, vecName, &objName, 0))
    return NULL;

  Tcl_DStringInit(&dString);
  if ((objName.name[0] == '#') && (strcmp(objName.name, "#auto") == 0)) {

    do {	/* Generate a unique vector name. */
      char string[200];

      snprintf(string, 200, "vector%d", dataPtr->nextId++);
      objName.name = string;
      qualName = MakeQualifiedName(&objName, &dString);
      hPtr = Tcl_FindHashEntry(&dataPtr->vectorTable, qualName);
    } while (hPtr != NULL);
  } else {
    const char *p;

    for (p = objName.name; *p != '\0'; p++) {
      if (!VECTOR_CHAR(*p)) {
	Tcl_AppendResult(interp, "bad vector name \"", objName.name,
			 "\": must contain digits, letters, underscore, or period",
			 (char *)NULL);
	goto error;
      }
    }
    qualName = MakeQualifiedName(&objName, &dString);
    vPtr = Vec_ParseElement((Tcl_Interp *)NULL, dataPtr, qualName, 
				NULL, NS_SEARCH_CURRENT);
  }
  if (vPtr == NULL) {
    hPtr = Tcl_CreateHashEntry(&dataPtr->vectorTable, qualName, &isNew);
    vPtr = Vec_New(dataPtr);
    vPtr->hashPtr = hPtr;
    vPtr->nsPtr = objName.nsPtr;

    vPtr->name = (const char*)Tcl_GetHashKey(&dataPtr->vectorTable, hPtr);
#ifdef NAMESPACE_DELETE_NOTIFY
    Blt_CreateNsDeleteNotify(interp, objName.nsPtr, vPtr, 
			     VectorInstDeleteProc);
#endif /* NAMESPACE_DELETE_NOTIFY */
    Tcl_SetHashValue(hPtr, vPtr);
  }
  if (cmdName != NULL) {
    Tcl_CmdInfo cmdInfo;

    if ((cmdName == vecName) ||
	((cmdName[0] == '#') && (strcmp(cmdName, "#auto")==0))) {
      cmdName = qualName;
    } 
    if (Tcl_GetCommandInfo(interp, (char *)cmdName, &cmdInfo)) {
      if (vPtr != cmdInfo.objClientData) {
	Tcl_AppendResult(interp, "command \"", cmdName,
			 "\" already exists", (char *)NULL);
	goto error;
      }
      /* We get here only if the old name is the same as the new. */
      goto checkVariable;
    }
  }
  if (vPtr->cmdToken != 0) {
    DeleteCommand(vPtr);	/* Command already exists, delete old first */
  }
  if (cmdName != NULL) {
    Tcl_DString dString2;
	
    Tcl_DStringInit(&dString2);
    if (cmdName != qualName) {
      if (!ParseObjectName(interp, cmdName, &objName, 0)) {
	goto error;
      }
      cmdName = MakeQualifiedName(&objName, &dString2);
    }
    vPtr->cmdToken = Tcl_CreateObjCommand(interp, (char *)cmdName, Vec_InstCmd,
					  vPtr, VectorInstDeleteProc);
    Tcl_DStringFree(&dString2);
  }
 checkVariable:
  if (varName != NULL) {
    if ((varName[0] == '#') && (strcmp(varName, "#auto") == 0)) {
      varName = qualName;
    }
    if (Vec_MapVariable(interp, vPtr, varName) != TCL_OK) {
      goto error;
    }
  }

  Tcl_DStringFree(&dString);
  *isNewPtr = isNew;
  return vPtr;

 error:
  Tcl_DStringFree(&dString);
  if (vPtr != NULL) {
    Vec_Free(vPtr);
  }
  return NULL;
}

int Blt::Vec_Duplicate(Vector* destPtr, Vector* srcPtr)
{
  size_t nBytes;
  size_t length;

  if (destPtr == srcPtr) {
    /* Copying the same vector. */
  }
  length = srcPtr->last - srcPtr->first + 1;
  if (Vec_ChangeLength(destPtr->interp, destPtr, length) != TCL_OK) {
    return TCL_ERROR;
  }
  nBytes = length * sizeof(double);
  memcpy(destPtr->valueArr, srcPtr->valueArr + srcPtr->first, nBytes);
  destPtr->offset = srcPtr->offset;
  return TCL_OK;
}


static int VectorNamesOp(ClientData clientData, Tcl_Interp* interp,
			 int objc, Tcl_Obj* const objv[])
{
  VectorInterpData* dataPtr = (VectorInterpData*)clientData;
  Tcl_Obj *listObjPtr;

  listObjPtr = Tcl_NewListObj(0, (Tcl_Obj **) NULL);
  if (objc == 2) {
    Tcl_HashEntry *hPtr;
    Tcl_HashSearch cursor;

    for (hPtr = Tcl_FirstHashEntry(&dataPtr->vectorTable, &cursor);
	 hPtr != NULL; hPtr = Tcl_NextHashEntry(&cursor)) {
      char *name = (char*)Tcl_GetHashKey(&dataPtr->vectorTable, hPtr);
      Tcl_ListObjAppendElement(interp, listObjPtr, 
			       Tcl_NewStringObj(name, -1));
    }
  } else {
    Tcl_HashEntry *hPtr;
    Tcl_HashSearch cursor;

    for (hPtr = Tcl_FirstHashEntry(&dataPtr->vectorTable, &cursor);
	 hPtr != NULL; hPtr = Tcl_NextHashEntry(&cursor)) {
      char *name = (char*)Tcl_GetHashKey(&dataPtr->vectorTable, hPtr);
      int i;
      for (i = 2; i < objc; i++) {
	char *pattern;

	pattern = Tcl_GetString(objv[i]);
	if (Tcl_StringMatch(name, pattern)) {
	  Tcl_ListObjAppendElement(interp, listObjPtr, 
				   Tcl_NewStringObj(name, -1));
	  break;
	}
      }
    }
  }
  Tcl_SetObjResult(interp, listObjPtr);
  return TCL_OK;
}

static int VectorCreate2(ClientData clientData, Tcl_Interp* interp,
			 int argStart, int objc, Tcl_Obj* const objv[])
{
  VectorInterpData *dataPtr = (VectorInterpData*)clientData;
  Vector* vPtr;
  int count, i;
  CreateSwitches switches;

  // Handle switches to the vector command and collect the vector name
  // arguments into an array.
  count = 0;
  vPtr = NULL;
  for (i = argStart; i < objc; i++) {
    char *string;

    string = Tcl_GetString(objv[i]);
    if (string[0] == '-') {
      break;
    }
  }
  count = i - argStart;
  if (count == 0) {
    Tcl_AppendResult(interp, "no vector names supplied", (char *)NULL);
    return TCL_ERROR;
  }
  memset(&switches, 0, sizeof(switches));
  if (ParseSwitches(interp, createSwitches, objc - i, objv + i, 
			&switches, BLT_SWITCH_DEFAULTS) < 0) {
    return TCL_ERROR;
  }
  if (count > 1) {
    if (switches.cmdName != NULL) {
      Tcl_AppendResult(interp, 
		       "can't specify more than one vector with \"-command\" switch",
		       (char *)NULL);
      goto error;
    }
    if (switches.varName != NULL) {
      Tcl_AppendResult(interp,
		       "can't specify more than one vector with \"-variable\" switch",
		       (char *)NULL);
      goto error;
    }
  }
  for (i = 0; i < count; i++) {
    char *leftParen, *rightParen;
    char *string;
    int isNew;
    int size, first, last;

    size = first = last = 0;
    string = Tcl_GetString(objv[i + argStart]);
    leftParen = strchr(string, '(');
    rightParen = strchr(string, ')');
    if (((leftParen != NULL) && (rightParen == NULL)) ||
	((leftParen == NULL) && (rightParen != NULL)) ||
	(leftParen > rightParen)) {
      Tcl_AppendResult(interp, "bad vector specification \"", string,
		       "\"", (char *)NULL);
      goto error;
    }
    if (leftParen != NULL) {
      int result;
      char *colon;

      *rightParen = '\0';
      colon = strchr(leftParen + 1, ':');
      if (colon != NULL) {

	/* Specification is in the form vecName(first:last) */
	*colon = '\0';
	result = Tcl_GetInt(interp, leftParen + 1, &first);
	if ((*(colon + 1) != '\0') && (result == TCL_OK)) {
	  result = Tcl_GetInt(interp, colon + 1, &last);
	  if (first > last) {
	    Tcl_AppendResult(interp, "bad vector range \"",
			     string, "\"", (char *)NULL);
	    result = TCL_ERROR;
	  }
	  size = (last - first) + 1;
	}
	*colon = ':';
      } else {
	/* Specification is in the form vecName(size) */
	result = Tcl_GetInt(interp, leftParen + 1, &size);
      }
      *rightParen = ')';
      if (result != TCL_OK) {
	goto error;
      }
      if (size < 0) {
	Tcl_AppendResult(interp, "bad vector size \"", string, "\"",
			 (char *)NULL);
	goto error;
      }
    }
    if (leftParen != NULL) {
      *leftParen = '\0';
    }
    /*
     * By default, we create a TCL command by the name of the vector.
     */
    vPtr = Vec_Create(dataPtr, string,
			  (switches.cmdName == NULL) ? string : switches.cmdName,
			  (switches.varName == NULL) ? string : switches.varName, &isNew);
    if (leftParen != NULL) {
      *leftParen = '(';
    }
    if (vPtr == NULL) {
      goto error;
    }
    vPtr->freeOnUnset = switches.watchUnset;
    vPtr->flush = switches.flush;
    vPtr->offset = first;
    if (size > 0) {
      if (Vec_ChangeLength(interp, vPtr, size) != TCL_OK) {
	goto error;
      }
    }
    if (!isNew) {
      if (vPtr->flush) {
	Vec_FlushCache(vPtr);
      }
      Vec_UpdateClients(vPtr);
    }
  }
  FreeSwitches(createSwitches, (char *)&switches, 0);
  if (vPtr != NULL) {
    /* Return the name of the last vector created  */
    Tcl_SetStringObj(Tcl_GetObjResult(interp), vPtr->name, -1);
  }
  return TCL_OK;
 error:
  FreeSwitches(createSwitches, (char *)&switches, 0);
  return TCL_ERROR;
}

static int VectorCreateOp(ClientData clientData, Tcl_Interp* interp,
			  int objc, Tcl_Obj* const objv[])
{
  return VectorCreate2(clientData, interp, 2, objc, objv);
}

static int VectorDestroyOp(ClientData clientData, Tcl_Interp* interp,
			   int objc,Tcl_Obj* const objv[])
{
  VectorInterpData *dataPtr = (VectorInterpData*)clientData;

  for (int ii=2; ii<objc; ii++) {
    Vector* vPtr;
    if (Vec_LookupName(dataPtr, Tcl_GetString(objv[ii]), &vPtr) != TCL_OK)
      return TCL_ERROR;
    Vec_Free(vPtr);
  }
  return TCL_OK;
}

static int VectorExprOp(ClientData clientData, Tcl_Interp* interp,
			int objc,    Tcl_Obj* const objv[])
{
  return Blt_ExprVector(interp, Tcl_GetString(objv[2]), (Blt_Vector* )NULL);
}

static Blt_OpSpec vectorCmdOps[] =
  {
    {"create", 1, (void*)VectorCreateOp, 3, 0,
     "vecName ?vecName...? ?switches...?",},
    {"destroy", 1, (void*)VectorDestroyOp, 3, 0,
     "vecName ?vecName...?",},
    {"expr", 1, (void*)VectorExprOp, 3, 3, "expression",},
    {"names", 1, (void*)VectorNamesOp, 2, 3, "?pattern?...",},
  };

static int nCmdOps = sizeof(vectorCmdOps) / sizeof(Blt_OpSpec);

int VectorObjCmd(ClientData clientData, Tcl_Interp* interp,
		 int objc, Tcl_Obj* const objv[])
{
  VectorCmdProc *proc;

  if (objc > 1) {
    char *string;
    char c;
    int i;
    Blt_OpSpec *specPtr;

    string = Tcl_GetString(objv[1]);
    c = string[0];
    for (specPtr = vectorCmdOps, i = 0; i < nCmdOps; i++, specPtr++) {
      if ((c == specPtr->name[0]) &&
	  (strcmp(string, specPtr->name) == 0)) {
	goto doOp;
      }
    }
    // The first argument is not an operation, so assume that its
    // actually the name of a vector to be created
    return VectorCreate2(clientData, interp, 1, objc, objv);
  }
 doOp:
  /* Do the usual vector operation lookup now. */
  proc = (VectorCmdProc*)GetOpFromObj(interp, nCmdOps, vectorCmdOps, 
				      BLT_OP_ARG1, objc, objv,0);
  if (proc == NULL) {
    return TCL_ERROR;
  }
  return (*proc) ((Vector*)clientData, interp, objc, objv);
}

static void VectorInterpDeleteProc(ClientData clientData, Tcl_Interp* interp)
{
  VectorInterpData *dataPtr = (VectorInterpData*)clientData;
  Tcl_HashEntry *hPtr;
  Tcl_HashSearch cursor;
    
  for (hPtr = Tcl_FirstHashEntry(&dataPtr->vectorTable, &cursor);
       hPtr != NULL; hPtr = Tcl_NextHashEntry(&cursor)) {
    Vector* vPtr = (Vector*)Tcl_GetHashValue(hPtr);
    vPtr->hashPtr = NULL;
    Vec_Free(vPtr);
  }
  Tcl_DeleteHashTable(&dataPtr->vectorTable);

  /* If any user-defined math functions were installed, remove them.  */
  Vec_UninstallMathFunctions(&dataPtr->mathProcTable);
  Tcl_DeleteHashTable(&dataPtr->mathProcTable);

  Tcl_DeleteHashTable(&dataPtr->indexProcTable);
  Tcl_DeleteAssocData(interp, VECTOR_THREAD_KEY);
  free(dataPtr);
}

VectorInterpData* Blt::Vec_GetInterpData(Tcl_Interp* interp)
{
  VectorInterpData *dataPtr;
  Tcl_InterpDeleteProc *proc;

  dataPtr = (VectorInterpData *)
    Tcl_GetAssocData(interp, VECTOR_THREAD_KEY, &proc);
  if (dataPtr == NULL) {
    dataPtr = (VectorInterpData*)malloc(sizeof(VectorInterpData));
    dataPtr->interp = interp;
    dataPtr->nextId = 0;
    Tcl_SetAssocData(interp, VECTOR_THREAD_KEY, VectorInterpDeleteProc,
		     dataPtr);
    Tcl_InitHashTable(&dataPtr->vectorTable, TCL_STRING_KEYS);
    Tcl_InitHashTable(&dataPtr->mathProcTable, TCL_STRING_KEYS);
    Tcl_InitHashTable(&dataPtr->indexProcTable, TCL_STRING_KEYS);
    Vec_InstallMathFunctions(&dataPtr->mathProcTable);
    Vec_InstallSpecialIndices(&dataPtr->indexProcTable);
    srand48(time((time_t *) NULL));
  }
  return dataPtr;
}

/* C Application interface to vectors */

int Blt_CreateVector2(Tcl_Interp* interp, const char *vecName,
		      const char *cmdName, const char *varName,
		      int initialSize, Blt_Vector* *vecPtrPtr)
{
  VectorInterpData *dataPtr;	/* Interpreter-specific data. */
  Vector* vPtr;
  int isNew;
  char *nameCopy;

  if (initialSize < 0) {
    Tcl_AppendResult(interp, "bad vector size \"", Itoa(initialSize),
		     "\"", (char *)NULL);
    return TCL_ERROR;
  }
  dataPtr = Vec_GetInterpData(interp);

  nameCopy = Blt_Strdup(vecName);
  vPtr = Vec_Create(dataPtr, nameCopy, cmdName, varName, &isNew);
  free(nameCopy);

  if (vPtr == NULL) {
    return TCL_ERROR;
  }
  if (initialSize > 0) {
    if (Vec_ChangeLength(interp, vPtr, initialSize) != TCL_OK) {
      return TCL_ERROR;
    }
  }
  if (vecPtrPtr != NULL) {
    *vecPtrPtr = (Blt_Vector* ) vPtr;
  }
  return TCL_OK;
}

int Blt_CreateVector(Tcl_Interp* interp, const char *name, int size,
		     Blt_Vector* *vecPtrPtr)
{
  return Blt_CreateVector2(interp, name, name, name, size, vecPtrPtr);
}

int Blt_DeleteVector(Blt_Vector* vecPtr)
{
  Vector* vPtr = (Vector* )vecPtr;

  Vec_Free(vPtr);
  return TCL_OK;
}

int Blt_DeleteVectorByName(Tcl_Interp* interp, const char *name)
{
  // If the vector name was passed via a read-only string (e.g. "x"), the
  // Vec_ParseElement routine will segfault when it tries to write into
  // the string.  Therefore make a writable copy and free it when we're done.
  char* nameCopy = Blt_Strdup(name);
  VectorInterpData *dataPtr = Vec_GetInterpData(interp);
  Vector* vPtr;
  int result = Vec_LookupName(dataPtr, nameCopy, &vPtr);
  free(nameCopy);

  if (result != TCL_OK)
    return TCL_ERROR;

  Vec_Free(vPtr);
  return TCL_OK;
}

int Blt_VectorExists2(Tcl_Interp* interp, const char *vecName)
{
  VectorInterpData *dataPtr;

  dataPtr = Vec_GetInterpData(interp);
  if (GetVectorObject(dataPtr, vecName, NS_SEARCH_BOTH) != NULL) {
    return 1;
  }
  return 0;
}

int Blt_VectorExists(Tcl_Interp* interp, const char *vecName)
{
  char *nameCopy;
  int result;

  /*
   * If the vector name was passed via a read-only string (e.g. "x"), the
   * Blt_VectorParseName routine will segfault when it tries to write into
   * the string.  Therefore make a writable copy and free it when we're
   * done.
   */
  nameCopy = Blt_Strdup(vecName);
  result = Blt_VectorExists2(interp, nameCopy);
  free(nameCopy);
  return result;
}

int Blt_GetVector(Tcl_Interp* interp, const char *name, Blt_Vector* *vecPtrPtr)
{
  VectorInterpData *dataPtr;	/* Interpreter-specific data. */
  Vector* vPtr;
  char *nameCopy;
  int result;

  dataPtr = Vec_GetInterpData(interp);
  /*
   * If the vector name was passed via a read-only string (e.g. "x"), the
   * Blt_VectorParseName routine will segfault when it tries to write into
   * the string.  Therefore make a writable copy and free it when we're
   * done.
   */
  nameCopy = Blt_Strdup(name);
  result = Vec_LookupName(dataPtr, nameCopy, &vPtr);
  free(nameCopy);
  if (result != TCL_OK) {
    return TCL_ERROR;
  }
  Vec_UpdateRange(vPtr);
  *vecPtrPtr = (Blt_Vector* ) vPtr;
  return TCL_OK;
}

int Blt_GetVectorFromObj(Tcl_Interp* interp, Tcl_Obj *objPtr,
			 Blt_Vector* *vecPtrPtr)
{
  VectorInterpData *dataPtr;	/* Interpreter-specific data. */
  Vector* vPtr;

  dataPtr = Vec_GetInterpData(interp);
  if (Vec_LookupName(dataPtr, Tcl_GetString(objPtr), &vPtr) != TCL_OK) {
    return TCL_ERROR;
  }
  Vec_UpdateRange(vPtr);
  *vecPtrPtr = (Blt_Vector* ) vPtr;
  return TCL_OK;
}

int Blt_ResetVector(Blt_Vector* vecPtr,	double *valueArr, int length,
		    int size, Tcl_FreeProc *freeProc)
{
  Vector* vPtr = (Vector* )vecPtr;

  if (size < 0) {
    Tcl_AppendResult(vPtr->interp, "bad array size", (char *)NULL);
    return TCL_ERROR;
  }
  return Vec_Reset(vPtr, valueArr, length, size, freeProc);
}

int Blt_ResizeVector(Blt_Vector* vecPtr, int length)
{
  Vector* vPtr = (Vector* )vecPtr;

  if (Vec_ChangeLength((Tcl_Interp *)NULL, vPtr, length) != TCL_OK) {
    Tcl_AppendResult(vPtr->interp, "can't resize vector \"", vPtr->name,
		     "\"", (char *)NULL);
    return TCL_ERROR;
  }
  if (vPtr->flush) {
    Vec_FlushCache(vPtr);
  }
  Vec_UpdateClients(vPtr);
  return TCL_OK;
}

Blt_VectorId Blt_AllocVectorId(Tcl_Interp* interp, const char *name)
{
  VectorInterpData *dataPtr;	/* Interpreter-specific data. */
  Vector* vPtr;
  VectorClient *clientPtr;
  Blt_VectorId clientId;
  int result;
  char *nameCopy;

  dataPtr = Vec_GetInterpData(interp);
  /*
   * If the vector name was passed via a read-only string (e.g. "x"), the
   * Blt_VectorParseName routine will segfault when it tries to write into
   * the string.  Therefore make a writable copy and free it when we're
   * done.
   */
  nameCopy = Blt_Strdup(name);
  result = Vec_LookupName(dataPtr, nameCopy, &vPtr);
  free(nameCopy);

  if (result != TCL_OK) {
    return (Blt_VectorId) 0;
  }
  /* Allocate a new client structure */
  clientPtr = (VectorClient*)calloc(1, sizeof(VectorClient));
  clientPtr->magic = VECTOR_MAGIC;

  /* Add the new client to the server's list of clients */
  clientPtr->link = vPtr->chain->append(clientPtr);
  clientPtr->serverPtr = vPtr;
  clientId = (Blt_VectorId) clientPtr;
  return clientId;
}

void Blt_SetVectorChangedProc(Blt_VectorId clientId,
			      Blt_VectorChangedProc *proc,
			      ClientData clientData)
{
  VectorClient *clientPtr = (VectorClient *)clientId;

  if (clientPtr->magic != VECTOR_MAGIC) {
    return;			/* Not a valid token */
  }
  clientPtr->clientData = clientData;
  clientPtr->proc = proc;
}

void Blt_FreeVectorId(Blt_VectorId clientId)
{
  VectorClient *clientPtr = (VectorClient *)clientId;

  if (clientPtr->magic != VECTOR_MAGIC)
    return;

  if (clientPtr->serverPtr != NULL) {
    // Remove the client from the server's list
    clientPtr->serverPtr->chain->deleteLink(clientPtr->link);
  }
  free(clientPtr);
}

const char* Blt_NameOfVectorId(Blt_VectorId clientId) 
{
  VectorClient *clientPtr = (VectorClient *)clientId;

  if ((clientPtr->magic != VECTOR_MAGIC) || (clientPtr->serverPtr == NULL)) {
    return NULL;
  }
  return clientPtr->serverPtr->name;
}

const char* Blt_NameOfVector(Blt_Vector* vecPtr) /* Vector to query. */
{
  Vector* vPtr = (Vector* )vecPtr;
  return vPtr->name;
}

int Blt_GetVectorById(Tcl_Interp* interp, Blt_VectorId clientId,
		      Blt_Vector* *vecPtrPtr)
{
  VectorClient *clientPtr = (VectorClient *)clientId;

  if (clientPtr->magic != VECTOR_MAGIC) {
    Tcl_AppendResult(interp, "bad vector token", (char *)NULL);
    return TCL_ERROR;
  }
  if (clientPtr->serverPtr == NULL) {
    Tcl_AppendResult(interp, "vector no longer exists", (char *)NULL);
    return TCL_ERROR;
  }
  Vec_UpdateRange(clientPtr->serverPtr);
  *vecPtrPtr = (Blt_Vector* ) clientPtr->serverPtr;
  return TCL_OK;
}

void Blt_InstallIndexProc(Tcl_Interp* interp, const char *string, 
			  Blt_VectorIndexProc *procPtr) 
{
  VectorInterpData *dataPtr;	/* Interpreter-specific data. */
  Tcl_HashEntry *hPtr;
  int isNew;

  dataPtr = Vec_GetInterpData(interp);
  hPtr = Tcl_CreateHashEntry(&dataPtr->indexProcTable, string, &isNew);
  if (procPtr == NULL) {
    Tcl_DeleteHashEntry(hPtr);
  } else {
    Tcl_SetHashValue(hPtr, procPtr);
  }
}

#define SWAP(a,b) tempr=(a);(a)=(b);(b)=tempr

/* routine by Brenner
 * data is the array of complex data points, perversely
 * starting at 1
 * nn is the number of complex points, i.e. half the length of data
 * isign is 1 for forward, -1 for inverse
 */
static void four1(double *data, unsigned long nn, int isign)
{
  unsigned long n,mmax,m,j,istep,i;
  double wtemp,wr,wpr,wpi,wi,theta;
  double tempr,tempi;
    
  n=nn << 1;
  j=1;
  for (i = 1;i<n;i+=2) {
    if (j > i) {
      SWAP(data[j],data[i]);
      SWAP(data[j+1],data[i+1]);
    }
    m=n >> 1;
    while (m >= 2 && j > m) {
      j -= m;
      m >>= 1;
    }
    j += m;
  }
  mmax=2;
  while (n > mmax) {
    istep=mmax << 1;
    theta=isign*(6.28318530717959/mmax);
    wtemp=sin(0.5*theta);
    wpr = -2.0*wtemp*wtemp;
    wpi=sin(theta);
    wr=1.0;
    wi=0.0;
    for (m=1;m<mmax;m+=2) {
      for (i=m;i<=n;i+=istep) {
	j=i+mmax;
	tempr=wr*data[j]-wi*data[j+1];
	tempi=wr*data[j+1]+wi*data[j];
	data[j]=data[i]-tempr;
	data[j+1]=data[i+1]-tempi;
	data[i] += tempr;
	data[i+1] += tempi;
      }
      wr=(wtemp=wr)*wpr-wi*wpi+wr;
      wi=wi*wpr+wtemp*wpi+wi;
    }
    mmax=istep;
  }
}
#undef SWAP

static int 
smallest_power_of_2_not_less_than(int x)
{
  int pow2 = 1;

  while (pow2 < x){
    pow2 <<= 1;
  }
  return pow2;
}

int Blt::Vec_FFT(Tcl_Interp* interp, Vector* realPtr, Vector* phasesPtr,
		Vector* freqPtr, double delta, int flags, Vector* srcPtr) 
{
  int length;
  int pow2len;
  double *paddedData;
  int i;
  double Wss = 0.0;
  /* TENTATIVE */
  int middle = 1;
  int noconstant;

  noconstant = (flags & FFT_NO_CONSTANT) ? 1 : 0;

  /* Length of the original vector. */
  length = srcPtr->last - srcPtr->first + 1;
  /* new length */
  pow2len = smallest_power_of_2_not_less_than( length );

  /* We do not do in-place FFTs */
  if (realPtr == srcPtr) {
    Tcl_AppendResult(interp, "real vector \"", realPtr->name, 
		     "\" can't be the same as the source", (char *)NULL);
    return TCL_ERROR;
  }
  if (phasesPtr != NULL) {
    if (phasesPtr == srcPtr) {
      Tcl_AppendResult(interp, "imaginary vector \"", phasesPtr->name, 
		       "\" can't be the same as the source", (char *)NULL);
      return TCL_ERROR;
    }
    if (Vec_ChangeLength(interp, phasesPtr, 
			     pow2len/2-noconstant+middle) != TCL_OK) {
      return TCL_ERROR;
    }
  }
  if (freqPtr != NULL) {
    if (freqPtr == srcPtr) {
      Tcl_AppendResult(interp, "frequency vector \"", freqPtr->name, 
		       "\" can't be the same as the source", (char *)NULL);
      return TCL_ERROR;
    }
    if (Vec_ChangeLength(interp, freqPtr, 
			     pow2len/2-noconstant+middle) != TCL_OK) {
      return TCL_ERROR;
    }
  }

  /* Allocate memory zero-filled array. */
  paddedData = (double*)calloc(pow2len * 2, sizeof(double));
  if (paddedData == NULL) {
    Tcl_AppendResult(interp, "can't allocate memory for padded data",
		     (char *)NULL);
    return TCL_ERROR;
  }
    
  /*
   * Since we just do real transforms, only even locations will be
   * filled with data.
   */
  if (flags & FFT_BARTLETT) {	/* Bartlett window 1 - ( (x - N/2) / (N/2) ) */
    double Nhalf = pow2len*0.5;
    double Nhalf_1 = 1.0 / Nhalf;
    double w;

    for (i = 0; i < length; i++) {
      w = 1.0 - fabs( (i-Nhalf) * Nhalf_1 );
      Wss += w;
      paddedData[2*i] = w * srcPtr->valueArr[i];
    }
    for(/*empty*/; i < pow2len; i++) {
      w = 1.0 - fabs((i-Nhalf) * Nhalf_1);
      Wss += w;
    }
  } else {			/* Squared window, i.e. no data windowing. */
    for (i = 0; i < length; i++) { 
      paddedData[2*i] = srcPtr->valueArr[i]; 
    }
    Wss = pow2len;
  }
    
  /* Fourier */
  four1(paddedData-1, pow2len, 1);
    
  /*
    for(i=0;i<pow2len;i++){
    printf( "(%f %f) ", paddedData[2*i], paddedData[2*i+1] );
    }
  */
    
  /* the spectrum is the modulus of the transforms, scaled by 1/N^2 */
  /* or 1/(N * Wss) for windowed data */
  if (flags & FFT_SPECTRUM) {
    double re, im, reS, imS;
    double factor = 1.0 / (pow2len*Wss);
    double *v = realPtr->valueArr;
	
    for (i = 0 + noconstant; i < pow2len / 2; i++) {
      re = paddedData[2*i];
      im = paddedData[2*i+1];
      reS = paddedData[2*pow2len-2*i-2];
      imS = paddedData[2*pow2len-2*i-1];
      v[i - noconstant] = factor * (
# if 0
				    hypot( paddedData[2*i], paddedData[2*i+1] )
				    + hypot(
					    paddedData[pow2len*2-2*i-2],
					    paddedData[pow2len*2-2*i-1]
					    )
# else
				    sqrt( re*re + im* im ) + sqrt( reS*reS + imS*imS )
# endif
				    );
    }
  } else {
    for(i = 0 + noconstant; i < pow2len / 2 + middle; i++) {
      realPtr->valueArr[i - noconstant] = paddedData[2*i];
    }
  }
  if( phasesPtr != NULL ){
    for (i = 0 + noconstant; i < pow2len / 2 + middle; i++) {
      phasesPtr->valueArr[i-noconstant] = paddedData[2*i+1];
    }
  }
    
  /* Compute frequencies */
  if (freqPtr != NULL) {
    double N = pow2len;
    double denom = 1.0 / N / delta;
    for( i=0+noconstant; i<pow2len/2+middle; i++ ){
      freqPtr->valueArr[i-noconstant] = ((double) i) * denom;
    }
  }
    
  /* Memory is necessarily dynamic, because nobody touched it ! */
  free(paddedData);
    
  realPtr->offset = 0;
  return TCL_OK;
}


int Blt::Vec_InverseFFT(Tcl_Interp* interp, Vector* srcImagPtr, 
		       Vector* destRealPtr, Vector* destImagPtr, Vector* srcPtr)
{
  int length;
  int pow2len;
  double *paddedData;
  int i;
  double oneOverN;

  if ((destRealPtr == srcPtr) || (destImagPtr == srcPtr )){
    /* we do not do in-place FFTs */
    return TCL_ERROR;
  }
  length = srcPtr->last - srcPtr->first + 1;

  /* minus one because of the magical middle element! */
  pow2len = smallest_power_of_2_not_less_than( (length-1)*2 );
  oneOverN = 1.0 / pow2len;

  if (Vec_ChangeLength(interp, destRealPtr, pow2len) != TCL_OK) {
    return TCL_ERROR;
  }
  if (Vec_ChangeLength(interp, destImagPtr, pow2len) != TCL_OK) {
    return TCL_ERROR;
  }

  if( length != (srcImagPtr->last - srcImagPtr->first + 1) ){
    Tcl_AppendResult(srcPtr->interp,
		     "the length of the imagPart vector must ",
		     "be the same as the real one", (char *)NULL);
    return TCL_ERROR;
  }

  paddedData = (double*)malloc( pow2len*2*sizeof(double) );
  if( paddedData == NULL ){
    if (interp != NULL) {
      Tcl_AppendResult(interp, "memory allocation failed", (char *)NULL);
    }
    return TCL_ERROR;
  }
  for(i=0;i<pow2len*2;i++) { paddedData[i] = 0.0; }
  for(i=0;i<length-1;i++){
    paddedData[2*i] = srcPtr->valueArr[i];
    paddedData[2*i+1] = srcImagPtr->valueArr[i];
    paddedData[pow2len*2 - 2*i - 2 ] = srcPtr->valueArr[i+1];
    paddedData[pow2len*2 - 2*i - 1 ] = - srcImagPtr->valueArr[i+1];
  }
  /* mythical middle element */
  paddedData[(length-1)*2] = srcPtr->valueArr[length-1];
  paddedData[(length-1)*2+1] = srcImagPtr->valueArr[length-1];

  /*
    for(i=0;i<pow2len;i++){
    printf( "(%f %f) ", paddedData[2*i], paddedData[2*i+1] );
    }
  */

  /* fourier */
  four1( paddedData-1, pow2len, -1 );

  /* put values in their places, normalising by 1/N */
  for(i=0;i<pow2len;i++){
    destRealPtr->valueArr[i] = paddedData[2*i] * oneOverN;
    destImagPtr->valueArr[i] = paddedData[2*i+1] * oneOverN;
  }

  /* memory is necessarily dynamic, because nobody touched it ! */
  free( paddedData );

  return TCL_OK;
}

static double FindSplit(Point2d *points, int i, int j, int *split)	
{    
  double maxDist2;
    
  maxDist2 = -1.0;
  if ((i + 1) < j) {
    int k;
    double a, b, c;	

    /* 
     * 
     *  dist2 P(k) =  |  1  P(i).x  P(i).y  |
     *		  |  1  P(j).x  P(j).y  |
     *                |  1  P(k).x  P(k).y  |
     *       ------------------------------------------
     *       (P(i).x - P(j).x)^2 + (P(i).y - P(j).y)^2
     */

    a = points[i].y - points[j].y;
    b = points[j].x - points[i].x;
    c = (points[i].x * points[j].y) - (points[i].y * points[j].x);
    for (k = (i + 1); k < j; k++) {
      double dist2;

      dist2 = (points[k].x * a) + (points[k].y * b) + c;
      if (dist2 < 0.0) {
	dist2 = -dist2;	
      }
      if (dist2 > maxDist2) {
	maxDist2 = dist2;	/* Track the maximum. */
	*split = k;
      }
    }
    /* Correction for segment length---should be redone if can == 0 */
    maxDist2 *= maxDist2 / (a * a + b * b);
  } 
  return maxDist2;
}

// Douglas-Peucker line simplification algorithm */
int Blt_SimplifyLine(Point2d *inputPts, int low, int high, double tolerance,
		     int *indices)
{
#define StackPush(a)	s++, stack[s] = (a)
#define StackPop(a)	(a) = stack[s], s--
#define StackEmpty()	(s < 0)
#define StackTop()	stack[s]
  int *stack;
  int split = -1; 
  double dist2, tolerance2;
  int s = -1;			/* Points to top stack item. */
  int count;

  stack = (int*)malloc(sizeof(int) * (high - low + 1));
  StackPush(high);
  count = 0;
  indices[count++] = 0;
  tolerance2 = tolerance * tolerance;
  while (!StackEmpty()) {
    dist2 = FindSplit(inputPts, low, StackTop(), &split);
    if (dist2 > tolerance2) {
      StackPush(split);
    } else {
      indices[count++] = StackTop();
      StackPop(low);
    }
  } 
  free(stack);
  return count;
}