summaryrefslogtreecommitdiffstats
path: root/generic/tclStringObj.c
blob: 300f2f9c8113e33eabd00599d60ff8f02866cd32 (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
/* 
 * tclStringObj.c --
 *
 *	This file contains procedures that implement string operations on Tcl
 *	objects.  Some string operations work with UTF strings and others
 *	require Unicode format.  Functions that require knowledge of the width
 *	of each character, such as indexing, operate on Unicode data.
 *
 *	A Unicode string is an internationalized string.  Conceptually, a
 *	Unicode string is an array of 16-bit quantities organized as a sequence
 *	of properly formed UTF-8 characters.  There is a one-to-one map between
 *	Unicode and UTF characters.  Because Unicode characters have a fixed
 *	width, operations such as indexing operate on Unicode data.  The String
 *	ojbect is opitmized for the case where each UTF char in a string is
 *	only one byte.  In this case, we store the value of numChars, but we
 *	don't store the Unicode data (unless Tcl_GetUnicode is explicitly
 *	called).
 *
 *	The String object type stores one or both formats.  The default
 *	behavior is to store UTF.  Once Unicode is calculated by a function, it
 *	is stored in the internal rep for future access (without an additional
 *	O(n) cost).
 *
 *	To allow many appends to be done to an object without constantly
 *	reallocating the space for the string or Unicode representation, we
 *	allocate double the space for the string or Unicode and use the
 *	internal representation to keep track of how much space is used
 *	vs. allocated.
 *
 * Copyright (c) 1995-1997 Sun Microsystems, Inc.
 * Copyright (c) 1999 by Scriptics Corporation.
 *
 * See the file "license.terms" for information on usage and redistribution
 * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 *
 * RCS: @(#) $Id: tclStringObj.c,v 1.16 2000/05/08 22:10:58 hobbs Exp $ */

#include "tclInt.h"

/*
 * Prototypes for procedures defined later in this file:
 */

static void		AppendUnicodeToUnicodeRep _ANSI_ARGS_((
    			    Tcl_Obj *objPtr, Tcl_UniChar *unicode,
			    int appendNumChars));
static void		AppendUnicodeToUtfRep _ANSI_ARGS_((
    			    Tcl_Obj *objPtr, Tcl_UniChar *unicode,
			    int numChars));
static void		AppendUtfToUnicodeRep _ANSI_ARGS_((Tcl_Obj *objPtr,
    			    char *bytes, int numBytes));
static void		AppendUtfToUtfRep _ANSI_ARGS_((Tcl_Obj *objPtr,
    			    char *bytes, int numBytes));

static void		FillUnicodeRep _ANSI_ARGS_((Tcl_Obj *objPtr));

static void		FreeStringInternalRep _ANSI_ARGS_((Tcl_Obj *objPtr));
static void		DupStringInternalRep _ANSI_ARGS_((Tcl_Obj *objPtr,
			    Tcl_Obj *copyPtr));
static int		SetStringFromAny _ANSI_ARGS_((Tcl_Interp *interp,
			    Tcl_Obj *objPtr));
static void		UpdateStringOfString _ANSI_ARGS_((Tcl_Obj *objPtr));

/*
 * The structure below defines the string Tcl object type by means of
 * procedures that can be invoked by generic object code.
 */

Tcl_ObjType tclStringType = {
    "string",				/* name */
    FreeStringInternalRep,		/* freeIntRepPro */
    DupStringInternalRep,		/* dupIntRepProc */
    UpdateStringOfString,		/* updateStringProc */
    SetStringFromAny			/* setFromAnyProc */
};

/*
 * The following structure is the internal rep for a String object.
 * It keeps track of how much memory has been used and how much has been
 * allocated for the Unicode and UTF string to enable growing and
 * shrinking of the UTF and Unicode reps of the String object with fewer
 * mallocs.  To optimize string length and indexing operations, this
 * structure also stores the number of characters (same of UTF and Unicode!)
 * once that value has been computed.
 */

typedef struct String {
    int numChars;		/* The number of chars in the string.
				 * -1 means this value has not been
				 * calculated. >= 0 means that there is a
				 * valid Unicode rep, or that the number
				 * of UTF bytes == the number of chars. */
    size_t allocated;		/* The amount of space actually allocated
				 * for the UTF string (minus 1 byte for
				 * the termination char). */
    size_t uallocated;		/* The amount of space actually allocated
				 * for the Unicode string. 0 means the
				 * Unicode string rep is invalid. */
    Tcl_UniChar unicode[2];	/* The array of Unicode chars.  The actual
				 * size of this field depends on the
				 * 'uallocated' field above. */
} String;

#define STRING_SIZE(len)	\
		((unsigned) (sizeof(String) + ((len-1) * sizeof(Tcl_UniChar))))
#define GET_STRING(objPtr) \
		((String *) (objPtr)->internalRep.otherValuePtr)
#define SET_STRING(objPtr, stringPtr) \
		(objPtr)->internalRep.otherValuePtr = (VOID *) (stringPtr)


/*
 *----------------------------------------------------------------------
 *
 * Tcl_NewStringObj --
 *
 *	This procedure is normally called when not debugging: i.e., when
 *	TCL_MEM_DEBUG is not defined. It creates a new string object and
 *	initializes it from the byte pointer and length arguments.
 *
 *	When TCL_MEM_DEBUG is defined, this procedure just returns the
 *	result of calling the debugging version Tcl_DbNewStringObj.
 *
 * Results:
 *	A newly created string object is returned that has ref count zero.
 *
 * Side effects:
 *	The new object's internal string representation will be set to a
 *	copy of the length bytes starting at "bytes". If "length" is
 *	negative, use bytes up to the first NULL byte; i.e., assume "bytes"
 *	points to a C-style NULL-terminated string. The object's type is set
 *	to NULL. An extra NULL is added to the end of the new object's byte
 *	array.
 *
 *----------------------------------------------------------------------
 */

#ifdef TCL_MEM_DEBUG
#undef Tcl_NewStringObj

Tcl_Obj *
Tcl_NewStringObj(bytes, length)
    CONST char *bytes;		/* Points to the first of the length bytes
				 * used to initialize the new object. */
    int length;			/* The number of bytes to copy from "bytes"
				 * when initializing the new object. If 
				 * negative, use bytes up to the first
				 * NULL byte. */
{
    return Tcl_DbNewStringObj(bytes, length, "unknown", 0);
}

#else /* if not TCL_MEM_DEBUG */

Tcl_Obj *
Tcl_NewStringObj(bytes, length)
    CONST char *bytes;		/* Points to the first of the length bytes
				 * used to initialize the new object. */
    int length;			/* The number of bytes to copy from "bytes"
				 * when initializing the new object. If 
				 * negative, use bytes up to the first
				 * NULL byte. */
{
    register Tcl_Obj *objPtr;

    if (length < 0) {
	length = (bytes? strlen(bytes) : 0);
    }
    TclNewObj(objPtr);
    TclInitStringRep(objPtr, bytes, length);
    return objPtr;
}
#endif /* TCL_MEM_DEBUG */

/*
 *----------------------------------------------------------------------
 *
 * Tcl_DbNewStringObj --
 *
 *	This procedure is normally called when debugging: i.e., when
 *	TCL_MEM_DEBUG is defined. It creates new string objects. It is the
 *	same as the Tcl_NewStringObj procedure above except that it calls
 *	Tcl_DbCkalloc directly with the file name and line number from its
 *	caller. This simplifies debugging since then the checkmem command
 *	will report the correct file name and line number when reporting
 *	objects that haven't been freed.
 *
 *	When TCL_MEM_DEBUG is not defined, this procedure just returns the
 *	result of calling Tcl_NewStringObj.
 *
 * Results:
 *	A newly created string object is returned that has ref count zero.
 *
 * Side effects:
 *	The new object's internal string representation will be set to a
 *	copy of the length bytes starting at "bytes". If "length" is
 *	negative, use bytes up to the first NULL byte; i.e., assume "bytes"
 *	points to a C-style NULL-terminated string. The object's type is set
 *	to NULL. An extra NULL is added to the end of the new object's byte
 *	array.
 *
 *----------------------------------------------------------------------
 */

#ifdef TCL_MEM_DEBUG

Tcl_Obj *
Tcl_DbNewStringObj(bytes, length, file, line)
    CONST char *bytes;		/* Points to the first of the length bytes
				 * used to initialize the new object. */
    int length;			/* The number of bytes to copy from "bytes"
				 * when initializing the new object. If 
				 * negative, use bytes up to the first
				 * NULL byte. */
    char *file;			/* The name of the source file calling this
				 * procedure; used for debugging. */
    int line;			/* Line number in the source file; used
				 * for debugging. */
{
    register Tcl_Obj *objPtr;

    if (length < 0) {
	length = (bytes? strlen(bytes) : 0);
    }
    TclDbNewObj(objPtr, file, line);
    TclInitStringRep(objPtr, bytes, length);
    return objPtr;
}

#else /* if not TCL_MEM_DEBUG */

Tcl_Obj *
Tcl_DbNewStringObj(bytes, length, file, line)
    CONST char *bytes;		/* Points to the first of the length bytes
				 * used to initialize the new object. */
    register int length;	/* The number of bytes to copy from "bytes"
				 * when initializing the new object. If 
				 * negative, use bytes up to the first
				 * NULL byte. */
    char *file;			/* The name of the source file calling this
				 * procedure; used for debugging. */
    int line;			/* Line number in the source file; used
				 * for debugging. */
{
    return Tcl_NewStringObj(bytes, length);
}
#endif /* TCL_MEM_DEBUG */

/*
 *---------------------------------------------------------------------------
 *
 * TclNewUnicodeObj --
 *
 *	This procedure is creates a new String object and initializes
 *	it from the given Unicode String.  If the Utf String is the same size
 *	as the Unicode string, don't duplicate the data.
 *
 * Results:
 *	The newly created object is returned.  This object will have no
 *	initial string representation.  The returned object has a ref count
 *	of 0.
 *
 * Side effects:
 *	Memory allocated for new object and copy of Unicode argument.
 *
 *---------------------------------------------------------------------------
 */

Tcl_Obj *
Tcl_NewUnicodeObj(unicode, numChars)
    Tcl_UniChar *unicode;	/* The unicode string used to initialize
				 * the new object. */
    int numChars;		/* Number of characters in the unicode
				 * string. */
{
    Tcl_Obj *objPtr;
    String *stringPtr;
    size_t uallocated;

    if (numChars < 0) {
	numChars = 0;
	if (unicode) {
	    while (unicode[numChars] != 0) { numChars++; }
	}
    }
    uallocated = (numChars + 1) * sizeof(Tcl_UniChar);

    /*
     * Create a new obj with an invalid string rep.
     */

    TclNewObj(objPtr);
    Tcl_InvalidateStringRep(objPtr);
    objPtr->typePtr = &tclStringType;

    stringPtr = (String *) ckalloc(STRING_SIZE(uallocated));
    stringPtr->numChars = numChars;
    stringPtr->uallocated = uallocated;
    stringPtr->allocated = 0;
    memcpy((VOID *) stringPtr->unicode, (VOID *) unicode, uallocated);
    stringPtr->unicode[numChars] = 0;
    SET_STRING(objPtr, stringPtr);
    return objPtr;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_GetCharLength --
 *
 *	Get the length of the Unicode string from the Tcl object.
 *
 * Results:
 *	Pointer to unicode string representing the unicode object.
 *
 * Side effects:
 *	Frees old internal rep.  Allocates memory for new "String"
 *	internal rep.
 *
 *----------------------------------------------------------------------
 */

int
Tcl_GetCharLength(objPtr)
    Tcl_Obj *objPtr;	/* The String object to get the num chars of. */
{
    String *stringPtr;
    
    SetStringFromAny(NULL, objPtr);
    stringPtr = GET_STRING(objPtr);

    /*
     * If numChars is unknown, then calculate the number of characaters
     * while populating the Unicode string.
     */
    
    if (stringPtr->numChars == -1) {

	stringPtr->numChars = Tcl_NumUtfChars(objPtr->bytes, objPtr->length);

 	if (stringPtr->numChars == objPtr->length) {

	    /*
	     * Since we've just calculated the number of chars, and all
	     * UTF chars are 1-byte long, we don't need to store the
	     * unicode string.
	     */

	    stringPtr->uallocated = 0;

	} else {
    
	    /*
	     * Since we've just calucalated the number of chars, and not
	     * all UTF chars are 1-byte long, go ahead and populate the
	     * unicode string.
	     */

	    FillUnicodeRep(objPtr);

	    /*
	     * We need to fetch the pointer again because we have just
	     * reallocated the structure to make room for the Unicode data.
	     */
	    
	    stringPtr = GET_STRING(objPtr);
	}
    }
    return stringPtr->numChars;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_GetUniChar --
 *
 *	Get the index'th Unicode character from the String object.  The
 *	index is assumed to be in the appropriate range.
 *
 * Results:
 *	Returns the index'th Unicode character in the Object.
 *
 * Side effects:
 *	Fills unichar with the index'th Unicode character.
 *
 *----------------------------------------------------------------------
 */

Tcl_UniChar
Tcl_GetUniChar(objPtr, index)
    Tcl_Obj *objPtr;	/* The object to get the Unicode charater from. */
    int index;		/* Get the index'th Unicode character. */
{
    Tcl_UniChar unichar;
    String *stringPtr;
    
    SetStringFromAny(NULL, objPtr);
    stringPtr = GET_STRING(objPtr);

    if (stringPtr->numChars == -1) {

	/*
	 * We haven't yet calculated the length, so we don't have the
	 * Unicode str.  We need to know the number of chars before we
	 * can do indexing.
	 */

	Tcl_GetCharLength(objPtr);

	/*
	 * We need to fetch the pointer again because we may have just
	 * reallocated the structure.
	 */
	
	stringPtr = GET_STRING(objPtr);
    }
    if (stringPtr->uallocated == 0) {

	/*
	 * All of the characters in the Utf string are 1 byte chars,
	 * so we don't store the unicode char.  We get the Utf string
	 * and convert the index'th byte to a Unicode character.
	 */
	
	Tcl_UtfToUniChar(&objPtr->bytes[index], &unichar);	
    } else {
	unichar = stringPtr->unicode[index];
    }
    return unichar;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_GetUnicode --
 *
 *	Get the Unicode form of the String object.  If
 *	the object is not already a String object, it will be converted
 *	to one.  If the String object does not have a Unicode rep, then
 *	one is create from the UTF string format.
 *
 * Results:
 *	Returns a pointer to the object's internal Unicode string.
 *
 * Side effects:
 *	Converts the object to have the String internal rep.
 *
 *----------------------------------------------------------------------
 */

Tcl_UniChar *
Tcl_GetUnicode(objPtr)
    Tcl_Obj *objPtr;	/* The object to find the unicode string for. */
{
    String *stringPtr;
    
    SetStringFromAny(NULL, objPtr);
    stringPtr = GET_STRING(objPtr);
    
    if ((stringPtr->numChars == -1) || (stringPtr->uallocated == 0)) {

	/*
	 * We haven't yet calculated the length, or all of the characters
	 * in the Utf string are 1 byte chars (so we didn't store the
	 * unicode str).  Since this function must return a unicode string,
	 * and one has not yet been stored, force the Unicode to be
	 * calculated and stored now.
	 */

	FillUnicodeRep(objPtr);

	/*
	 * We need to fetch the pointer again because we have just
	 * reallocated the structure to make room for the Unicode data.
	 */
	
	stringPtr = GET_STRING(objPtr);
    }
    return stringPtr->unicode;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_GetRange --
 *
 *	Create a Tcl Object that contains the chars between first and last
 *	of the object indicated by "objPtr".  If the object is not already
 *	a String object, convert it to one.  The first and last indices
 *	are assumed to be in the appropriate range.
 *
 * Results:
 *	Returns a new Tcl Object of the String type.
 *
 * Side effects:
 *	Changes the internal rep of "objPtr" to the String type.
 *
 *----------------------------------------------------------------------
 */

Tcl_Obj*
Tcl_GetRange(objPtr, first, last)
   
 Tcl_Obj *objPtr;		/* The Tcl object to find the range of. */
    int first;			/* First index of the range. */
    int last;			/* Last index of the range. */
{
    Tcl_Obj *newObjPtr;		/* The Tcl object to find the range of. */
    String *stringPtr;
    
    SetStringFromAny(NULL, objPtr);
    stringPtr = GET_STRING(objPtr);

    if (stringPtr->numChars == -1) {
    
	/*
	 * We haven't yet calculated the length, so we don't have the
	 * Unicode str.  We need to know the number of chars before we
	 * can do indexing.
	 */

	Tcl_GetCharLength(objPtr);

	/*
	 * We need to fetch the pointer again because we may have just
	 * reallocated the structure.
	 */
	
	stringPtr = GET_STRING(objPtr);
    }

    if (stringPtr->numChars == objPtr->length) {
	char *str = Tcl_GetString(objPtr);

	/*
	 * All of the characters in the Utf string are 1 byte chars,
	 * so we don't store the unicode char.  Create a new string
	 * object containing the specified range of chars.
	 */
	
	newObjPtr = Tcl_NewStringObj(&str[first], last-first+1);

	/*
	 * Since we know the new string only has 1-byte chars, we
	 * can set it's numChars field.
	 */
	
	SetStringFromAny(NULL, newObjPtr);
	stringPtr = GET_STRING(newObjPtr);
	stringPtr->numChars = last-first+1;
    } else {
	newObjPtr = Tcl_NewUnicodeObj(stringPtr->unicode + first,
		last-first+1);
    }
    return newObjPtr;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_SetStringObj --
 *
 *	Modify an object to hold a string that is a copy of the bytes
 *	indicated by the byte pointer and length arguments. 
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The object's string representation will be set to a copy of
 *	the "length" bytes starting at "bytes". If "length" is negative, use
 *	bytes up to the first NULL byte; i.e., assume "bytes" points to a
 *	C-style NULL-terminated string. The object's old string and internal
 *	representations are freed and the object's type is set NULL.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_SetStringObj(objPtr, bytes, length)
    register Tcl_Obj *objPtr;	/* Object whose internal rep to init. */
    char *bytes;		/* Points to the first of the length bytes
				 * used to initialize the object. */
    register int length;	/* The number of bytes to copy from "bytes"
				 * when initializing the object. If 
				 * negative, use bytes up to the first
				 * NULL byte.*/
{
    register Tcl_ObjType *oldTypePtr = objPtr->typePtr;

    /*
     * Free any old string rep, then set the string rep to a copy of
     * the length bytes starting at "bytes".
     */

    if (Tcl_IsShared(objPtr)) {
	panic("Tcl_SetStringObj called with shared object");
    }

    /*
     * Set the type to NULL and free any internal rep for the old type.
     */

    if ((oldTypePtr != NULL) && (oldTypePtr->freeIntRepProc != NULL)) {
	oldTypePtr->freeIntRepProc(objPtr);
    }
    objPtr->typePtr = NULL;

    Tcl_InvalidateStringRep(objPtr);
    if (length < 0) {
	length = (bytes? strlen(bytes) : 0);
    }
    TclInitStringRep(objPtr, bytes, length);
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_SetObjLength --
 *
 *	This procedure changes the length of the string representation
 *	of an object.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	If the size of objPtr's string representation is greater than
 *	length, then it is reduced to length and a new terminating null
 *	byte is stored in the strength.  If the length of the string
 *	representation is greater than length, the storage space is
 *	reallocated to the given length; a null byte is stored at the
 *	end, but other bytes past the end of the original string
 *	representation are undefined.  The object's internal
 *	representation is changed to "expendable string".
 *
 *----------------------------------------------------------------------
 */

void
Tcl_SetObjLength(objPtr, length)
    register Tcl_Obj *objPtr;	/* Pointer to object.  This object must
				 * not currently be shared. */
    register int length;	/* Number of bytes desired for string
				 * representation of object, not including
				 * terminating null byte. */
{
    char *new;
    String *stringPtr;

    if (Tcl_IsShared(objPtr)) {
	panic("Tcl_SetObjLength called with shared object");
    }
    SetStringFromAny(NULL, objPtr);
        
    /*
     * Invalidate the unicode data.
     */

    stringPtr = GET_STRING(objPtr);
    stringPtr->numChars = -1;
    stringPtr->uallocated = 0;

    if (length > (int) stringPtr->allocated) {

	/*
	 * Not enough space in current string. Reallocate the string
	 * space and free the old string.
	 */

	new = (char *) ckalloc((unsigned) (length+1));
	if (objPtr->bytes != NULL) {
	    memcpy((VOID *) new, (VOID *) objPtr->bytes,
		    (size_t) objPtr->length);
	    Tcl_InvalidateStringRep(objPtr);
	}
	objPtr->bytes = new;
	stringPtr->allocated = length;
    }
    
    objPtr->length = length;
    if ((objPtr->bytes != NULL) && (objPtr->bytes != tclEmptyStringRep)) {
	objPtr->bytes[length] = 0;
    }
}

/*
 *---------------------------------------------------------------------------
 *
 * TclSetUnicodeObj --
 *
 *	Modify an object to hold the Unicode string indicated by "unicode".
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Memory allocated for new "String" internal rep.
 *
 *---------------------------------------------------------------------------
 */

void
Tcl_SetUnicodeObj(objPtr, unicode, numChars)
    Tcl_Obj *objPtr;		/* The object to set the string of. */
    Tcl_UniChar *unicode;	/* The unicode string used to initialize
				 * the object. */
    int numChars;		/* Number of characters in the unicode
				 * string. */
{
    Tcl_ObjType *typePtr;
    String *stringPtr;
    size_t uallocated;

    if (numChars < 0) {
	numChars = 0;
	if (unicode) {
	    while (unicode[numChars] != 0) { numChars++; }
	}
    }
    uallocated = (numChars + 1) * sizeof(Tcl_UniChar);

    /*
     * Free the internal rep if one exists, and invalidate the string rep.
     */

    typePtr = objPtr->typePtr;
    if ((typePtr != NULL) && (typePtr->freeIntRepProc) != NULL) {
	(*typePtr->freeIntRepProc)(objPtr);
    }
    objPtr->typePtr = &tclStringType;

    /*
     * Allocate enough space for the String structure + Unicode string.
     */
	
    stringPtr = (String *) ckalloc(STRING_SIZE(uallocated));
    stringPtr->numChars = numChars;
    stringPtr->uallocated = uallocated;
    stringPtr->allocated = 0;
    memcpy((VOID *) stringPtr->unicode, (VOID *) unicode, uallocated);
    stringPtr->unicode[numChars] = 0;
    SET_STRING(objPtr, stringPtr);
    Tcl_InvalidateStringRep(objPtr);
    return;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_AppendToObj --
 *
 *	This procedure appends a sequence of bytes to an object.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The bytes at *bytes are appended to the string representation
 *	of objPtr.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_AppendToObj(objPtr, bytes, length)
    register Tcl_Obj *objPtr;	/* Points to the object to append to. */
    char *bytes;		/* Points to the bytes to append to the
				 * object. */
    register int length;	/* The number of bytes to append from
				 * "bytes". If < 0, then append all bytes
				 * up to NULL byte. */
{
    String *stringPtr;

    if (Tcl_IsShared(objPtr)) {
	panic("Tcl_AppendToObj called with shared object");
    }
    
    SetStringFromAny(NULL, objPtr);

    if (length < 0) {
	length = (bytes ? strlen(bytes) : 0);
    }
    if (length == 0) {
	return;
    }

    /*
     * If objPtr has a valid Unicode rep, then append the Unicode
     * conversion of "bytes" to the objPtr's Unicode rep, otherwise
     * append "bytes" to objPtr's string rep.
     */

    stringPtr = GET_STRING(objPtr);
    if (stringPtr->uallocated > 0) {
	AppendUtfToUnicodeRep(objPtr, bytes, length);

	stringPtr = GET_STRING(objPtr);
    } else {
	AppendUtfToUtfRep(objPtr, bytes, length);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_AppendUnicodeToObj --
 *
 *	This procedure appends a Unicode string to an object in the
 *	most efficient manner possible.  Length must be >= 0.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Invalidates the string rep and creates a new Unicode string.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_AppendUnicodeToObj(objPtr, unicode, length)
    register Tcl_Obj *objPtr;	/* Points to the object to append to. */
    Tcl_UniChar *unicode;	/* The unicode string to append to the
			         * object. */
    int length;			/* Number of chars in "unicode". */
{
    String *stringPtr;

    if (Tcl_IsShared(objPtr)) {
	panic("Tcl_AppendUnicodeToObj called with shared object");
    }

    if (length == 0) {
	return;
    }

    SetStringFromAny(NULL, objPtr);

    /*
     * TEMPORARY!!!  This is terribly inefficient, but it works, and Don
     * needs for me to check this stuff in ASAP.  -Melissa
     */
    
/*     UpdateStringOfString(objPtr); */
/*     AppendUnicodeToUtfRep(objPtr, unicode, length); */
/*     return; */

    /*
     * If objPtr has a valid Unicode rep, then append the "unicode"
     * to the objPtr's Unicode rep, otherwise the UTF conversion of
     * "unicode" to objPtr's string rep.
     */

    stringPtr = GET_STRING(objPtr);
    if (stringPtr->uallocated > 0) {
	AppendUnicodeToUnicodeRep(objPtr, unicode, length);
    } else {
	AppendUnicodeToUtfRep(objPtr, unicode, length);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_AppendObjToObj --
 *
 *	This procedure appends the string rep of one object to another.
 *	"objPtr" cannot be a shared object.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The string rep of appendObjPtr is appended to the string 
 *	representation of objPtr.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_AppendObjToObj(objPtr, appendObjPtr)
    Tcl_Obj *objPtr;		/* Points to the object to append to. */
    Tcl_Obj *appendObjPtr;	/* Object to append. */
{
    String *stringPtr;
    int length, numChars, allOneByteChars;
    char *bytes;

    SetStringFromAny(NULL, objPtr);

    /*
     * If objPtr has a valid Unicode rep, then get a Unicode string
     * from appendObjPtr and append it.
     */

    stringPtr = GET_STRING(objPtr);
    if (stringPtr->uallocated > 0) {
	
	/*
	 * If appendObjPtr is not of the "String" type, don't convert it.
	 */

	if (appendObjPtr->typePtr == &tclStringType) {
	    stringPtr = GET_STRING(appendObjPtr);
	    if ((stringPtr->numChars == -1)
		    || (stringPtr->uallocated == 0)) {
		
		/*
		 * If appendObjPtr is a string obj with no valide Unicode
		 * rep, then fill its unicode rep.
		 */

		FillUnicodeRep(appendObjPtr);
		stringPtr = GET_STRING(appendObjPtr);
	    }
	    AppendUnicodeToUnicodeRep(objPtr, stringPtr->unicode,
		    stringPtr->numChars);
	} else {
	    bytes = Tcl_GetStringFromObj(appendObjPtr, &length);
	    AppendUtfToUnicodeRep(objPtr, bytes, length);
	}
	return;
    }

    /*
     * Append to objPtr's UTF string rep.  If we know the number of
     * characters in both objects before appending, then set the combined
     * number of characters in the final (appended-to) object.
     */

    bytes = Tcl_GetStringFromObj(appendObjPtr, &length);

    allOneByteChars = 0;
    numChars = stringPtr->numChars;
    if ((numChars >= 0) && (appendObjPtr->typePtr == &tclStringType)) {
	stringPtr = GET_STRING(appendObjPtr);
	if ((stringPtr->numChars >= 0) && (stringPtr->numChars == length)) {
	    numChars += stringPtr->numChars;
	    allOneByteChars = 1;
	}
    }

    AppendUtfToUtfRep(objPtr, bytes, length);

    if (allOneByteChars) {
	stringPtr = GET_STRING(objPtr);
	stringPtr->numChars = numChars;
    }
}

/*
 *----------------------------------------------------------------------
 *
 * AppendUnicodeToUnicodeRep --
 *
 *	This procedure appends the contents of "unicode" to the Unicode
 *	rep of "objPtr".  objPtr must already have a valid Unicode rep.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	objPtr's internal rep is reallocated.
 *
 *----------------------------------------------------------------------
 */

static void
AppendUnicodeToUnicodeRep(objPtr, unicode, appendNumChars)
    Tcl_Obj *objPtr;	      /* Points to the object to append to. */
    Tcl_UniChar *unicode;     /* String to append. */
    int appendNumChars;	      /* Number of chars of "unicode" to append. */
{
    String *stringPtr;
    int numChars;
    size_t newSize;

    if (appendNumChars < 0) {
	appendNumChars = 0;
	if (unicode) {
	    while (unicode[appendNumChars] != 0) { appendNumChars++; }
	}
    }
    if (appendNumChars == 0) {
	return;
    }

    SetStringFromAny(NULL, objPtr);
    stringPtr = GET_STRING(objPtr);
    
    /*
     * If not enough space has been allocated for the unicode rep,
     * reallocate the internal rep object with double the amount of
     * space needed, so the unicode string can grow without being
     * reallocated.
     */

    numChars = stringPtr->numChars + appendNumChars;
    newSize = (numChars + 1) * sizeof(Tcl_UniChar);

    if (newSize > stringPtr->uallocated) {
	stringPtr->uallocated = newSize * 2;
	stringPtr = (String *) ckrealloc((char*)stringPtr,
		STRING_SIZE(stringPtr->uallocated));
	SET_STRING(objPtr, stringPtr);
    }

    /*
     * Copy the new string onto the end of the old string, then add the
     * trailing null.
     */

    memcpy((VOID*) (stringPtr->unicode + stringPtr->numChars), unicode,
	    appendNumChars * sizeof(Tcl_UniChar));
    stringPtr->unicode[numChars] = 0;
    stringPtr->numChars = numChars;

    SET_STRING(objPtr, stringPtr);
    Tcl_InvalidateStringRep(objPtr);
}

/*
 *----------------------------------------------------------------------
 *
 * AppendUnicodeToUtfRep --
 *
 *	This procedure converts the contents of "unicode" to UTF and
 *	appends the UTF to the string rep of "objPtr".
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	objPtr's internal rep is reallocated.
 *
 *----------------------------------------------------------------------
 */

static void
AppendUnicodeToUtfRep(objPtr, unicode, numChars)
    Tcl_Obj *objPtr;	      /* Points to the object to append to. */
    Tcl_UniChar *unicode;     /* String to convert to UTF. */
    int numChars;	      /* Number of chars of "unicode" to convert. */
{
    Tcl_DString dsPtr;
    char *bytes;
    
    if (numChars < 0) {
	numChars = 0;
	if (unicode) {
	    while (unicode[numChars] != 0) { numChars++; }
	}
    }
    if (numChars == 0) {
	return;
    }

    Tcl_DStringInit(&dsPtr);
    bytes = (char *)Tcl_UniCharToUtfDString(unicode, numChars, &dsPtr);
    AppendUtfToUtfRep(objPtr, bytes, Tcl_DStringLength(&dsPtr));
    Tcl_DStringFree(&dsPtr);
}

/*
 *----------------------------------------------------------------------
 *
 * AppendUtfToUnicodeRep --
 *
 *	This procedure converts the contents of "bytes" to Unicode and
 *	appends the Unicode to the Unicode rep of "objPtr".  objPtr must
 *	already have a valid Unicode rep.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	objPtr's internal rep is reallocated.
 *
 *----------------------------------------------------------------------
 */

static void
AppendUtfToUnicodeRep(objPtr, bytes, numBytes)
    Tcl_Obj *objPtr;	/* Points to the object to append to. */
    char *bytes;		/* String to convert to Unicode. */
    int numBytes;	/* Number of bytes of "bytes" to convert. */
{
    Tcl_DString dsPtr;
    int numChars;
    Tcl_UniChar *unicode;

    if (numBytes < 0) {
	numBytes = (bytes ? strlen(bytes) : 0);
    }
    if (numBytes == 0) {
	return;
    }
    
    Tcl_DStringInit(&dsPtr);
    numChars = Tcl_NumUtfChars(bytes, numBytes);
    unicode = (Tcl_UniChar *)Tcl_UtfToUniCharDString(bytes, numBytes, &dsPtr);
    AppendUnicodeToUnicodeRep(objPtr, unicode, numChars);
    Tcl_DStringFree(&dsPtr);
}

/*
 *----------------------------------------------------------------------
 *
 * AppendUtfToUtfRep --
 *
 *	This procedure appends "numBytes" bytes of "bytes" to the UTF string
 *	rep of "objPtr".  objPtr must already have a valid String rep.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	objPtr's internal rep is reallocated.
 *
 *----------------------------------------------------------------------
 */

static void
AppendUtfToUtfRep(objPtr, bytes, numBytes)
    Tcl_Obj *objPtr;	/* Points to the object to append to. */
    char *bytes;	/* String to append. */
    int numBytes;	/* Number of bytes of "bytes" to append. */
{
    String *stringPtr;
    int newLength, oldLength;

    if (numBytes < 0) {
	numBytes = (bytes ? strlen(bytes) : 0);
    }
    if (numBytes == 0) {
	return;
    }

    /*
     * Copy the new string onto the end of the old string, then add the
     * trailing null.
     */

    oldLength = objPtr->length;
    newLength = numBytes + oldLength;

    stringPtr = GET_STRING(objPtr);
    if (newLength > (int) stringPtr->allocated) {

	/*
	 * There isn't currently enough space in the string
	 * representation so allocate additional space.  Overallocate the
	 * space by doubling it so that we won't have to do as much
	 * reallocation in the future.
	 */

	Tcl_SetObjLength(objPtr, 2*newLength);
    } else {

	/*
	 * Invalidate the unicode data.
	 */
	
	stringPtr->numChars = -1;
	stringPtr->uallocated = 0;
    }
    
    memcpy((VOID *) (objPtr->bytes + oldLength), (VOID *) bytes,
	    (size_t) numBytes);
    objPtr->bytes[newLength] = 0;
    objPtr->length = newLength;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_AppendStringsToObjVA --
 *
 *	This procedure appends one or more null-terminated strings
 *	to an object.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The contents of all the string arguments are appended to the
 *	string representation of objPtr.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_AppendStringsToObjVA (objPtr, argList)
    Tcl_Obj *objPtr;		/* Points to the object to append to. */
    va_list argList;		/* Variable argument list. */
{
#define STATIC_LIST_SIZE 16
    String *stringPtr;
    int newLength, oldLength;
    register char *string, *dst;
    char *static_list[STATIC_LIST_SIZE];
    char **args = static_list;
    int nargs_space = STATIC_LIST_SIZE;
    int nargs, i;

    if (Tcl_IsShared(objPtr)) {
	panic("Tcl_AppendStringsToObj called with shared object");
    }

    SetStringFromAny(NULL, objPtr);

    /*
     * Figure out how much space is needed for all the strings, and
     * expand the string representation if it isn't big enough. If no
     * bytes would be appended, just return.  Note that on some platforms
     * (notably OS/390) the argList is an array so we need to use memcpy.
     */

    nargs = 0;
    newLength = oldLength = objPtr->length;
    while (1) {
	string = va_arg(argList, char *);
	if (string == NULL) {
	    break;
	}
 	if (nargs >= nargs_space) {
 	    /* 
 	     * Expand the args buffer
 	     */
 	    nargs_space += STATIC_LIST_SIZE;
 	    if (args == static_list) {
 	    	args = (void *)ckalloc(nargs_space * sizeof(char *));
 		for (i = 0; i < nargs; ++i) {
 		    args[i] = static_list[i];
 		}
 	    } else {
 		args = (void *)ckrealloc((void *)args,
			nargs_space * sizeof(char *));
 	    }
 	}
	newLength += strlen(string);
	args[nargs++] = string;
    }
    if (newLength == oldLength) {
	goto done;
    }

    stringPtr = GET_STRING(objPtr);
    if (newLength > (int) stringPtr->allocated) {

	/*
	 * There isn't currently enough space in the string
	 * representation so allocate additional space.  If the current
	 * string representation isn't empty (i.e. it looks like we're
	 * doing a series of appends) then overallocate the space so
	 * that we won't have to do as much reallocation in the future.
	 */

	Tcl_SetObjLength(objPtr,
		(objPtr->length == 0) ? newLength : 2*newLength);
    }

    /*
     * Make a second pass through the arguments, appending all the
     * strings to the object.
     */

    dst = objPtr->bytes + oldLength;
    for (i = 0; i < nargs; ++i) {
 	string = args[i];
	if (string == NULL) {
	    break;
	}
	while (*string != 0) {
	    *dst = *string;
	    dst++;
	    string++;
	}
    }

    /*
     * Add a null byte to terminate the string.  However, be careful:
     * it's possible that the object is totally empty (if it was empty
     * originally and there was nothing to append).  In this case dst is
     * NULL; just leave everything alone.
     */

    if (dst != NULL) {
	*dst = 0;
    }
    objPtr->length = newLength;

    done:
    /*
     * If we had to allocate a buffer from the heap, 
     * free it now.
     */
 
    if (args != static_list) {
     	ckfree((void *)args);
    }
#undef STATIC_LIST_SIZE
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_AppendStringsToObj --
 *
 *	This procedure appends one or more null-terminated strings
 *	to an object.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The contents of all the string arguments are appended to the
 *	string representation of objPtr.
 *
 *----------------------------------------------------------------------
 */

void
Tcl_AppendStringsToObj TCL_VARARGS_DEF(Tcl_Obj *,arg1)
{
    register Tcl_Obj *objPtr;
    va_list argList;

    objPtr = TCL_VARARGS_START(Tcl_Obj *,arg1,argList);
    Tcl_AppendStringsToObjVA(objPtr, argList);
    va_end(argList);
}

/*
 *---------------------------------------------------------------------------
 *
 * FillUnicodeRep --
 *
 *	Populate the Unicode internal rep with the Unicode form of its string
 *	rep.  The object must alread have a "String" internal rep.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Reallocates the String internal rep.
 *
 *---------------------------------------------------------------------------
 */

static void
FillUnicodeRep(objPtr)
    Tcl_Obj *objPtr;	/* The object in which to fill the unicode rep. */
{
    String *stringPtr;
    size_t uallocated;
    char *src, *srcEnd;
    Tcl_UniChar *dst;
    src = objPtr->bytes;
    
    stringPtr = GET_STRING(objPtr);
    if (stringPtr->numChars == -1) {
	stringPtr->numChars = Tcl_NumUtfChars(src, objPtr->length);
    }

    uallocated = stringPtr->numChars * sizeof(Tcl_UniChar);
    if (uallocated > stringPtr->uallocated) {
    
	/*
	 * If not enough space has been allocated for the unicode rep,
	 * reallocate the internal rep object.
	 */

	/*
	 * There isn't currently enough space in the Unicode
	 * representation so allocate additional space.  If the current
	 * Unicode representation isn't empty (i.e. it looks like we've
	 * done some appends) then overallocate the space so
	 * that we won't have to do as much reallocation in the future.
	 */

	if (stringPtr->uallocated > 0) {
	    uallocated *= 2;
	}
	stringPtr = (String *) ckrealloc((char*) stringPtr,
		STRING_SIZE(uallocated));
	stringPtr->uallocated = uallocated;
    }

    /*
     * Convert src to Unicode and store the coverted data in "unicode".
     */
    
    srcEnd = src + objPtr->length;
    for (dst = stringPtr->unicode; src < srcEnd; dst++) {
	src += Tcl_UtfToUniChar(src, dst);
    }
    *dst = 0;
    
    SET_STRING(objPtr, stringPtr);
}

/*
 *----------------------------------------------------------------------
 *
 * DupStringInternalRep --
 *
 *	Initialize the internal representation of a new Tcl_Obj to a
 *	copy of the internal representation of an existing string object.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	copyPtr's internal rep is set to a copy of srcPtr's internal
 *	representation.
 *
 *----------------------------------------------------------------------
 */

static void
DupStringInternalRep(srcPtr, copyPtr)
    register Tcl_Obj *srcPtr;	/* Object with internal rep to copy.  Must
				 * have an internal rep of type "String". */
    register Tcl_Obj *copyPtr;	/* Object with internal rep to set.  Must
				 * not currently have an internal rep.*/
{
    String *srcStringPtr = GET_STRING(srcPtr);
    String *copyStringPtr = NULL;

    /*
     * If the src obj is a string of 1-byte Utf chars, then copy the
     * string rep of the source object and create an "empty" Unicode
     * internal rep for the new object.  Otherwise, copy Unicode
     * internal rep, and invalidate the string rep of the new object.
     */
    
    if (srcStringPtr->uallocated == 0) {
    	copyStringPtr = (String *) ckalloc(sizeof(String));
	copyStringPtr->uallocated = 0;
    } else {
	copyStringPtr = (String *) ckalloc(
	    STRING_SIZE(srcStringPtr->uallocated));
	copyStringPtr->uallocated = srcStringPtr->uallocated;

	memcpy((VOID *) copyStringPtr->unicode,
		(VOID *) srcStringPtr->unicode,
		(size_t) srcStringPtr->numChars * sizeof(Tcl_UniChar));
	copyStringPtr->unicode[srcStringPtr->numChars] = 0;
    }
    copyStringPtr->numChars = srcStringPtr->numChars;
    copyStringPtr->allocated = srcStringPtr->allocated;

    /*
     * Tricky point: the string value was copied by generic object
     * management code, so it doesn't contain any extra bytes that
     * might exist in the source object.
     */

    copyStringPtr->allocated = copyPtr->length;

    SET_STRING(copyPtr, copyStringPtr);
    copyPtr->typePtr = &tclStringType;
}

/*
 *----------------------------------------------------------------------
 *
 * SetStringFromAny --
 *
 *	Create an internal representation of type "String" for an object.
 *
 * Results:
 *	This operation always succeeds and returns TCL_OK.
 *
 * Side effects:
 *	Any old internal reputation for objPtr is freed and the
 *	internal representation is set to "String".
 *
 *----------------------------------------------------------------------
 */

static int
SetStringFromAny(interp, objPtr)
    Tcl_Interp *interp;		/* Used for error reporting if not NULL. */
    Tcl_Obj *objPtr;		/* The object to convert. */
{
    String *stringPtr;

    /*
     * The Unicode object is opitmized for the case where each UTF char
     * in a string is only one byte.  In this case, we store the value of
     * numChars, but we don't copy the bytes to the unicodeObj->unicode.
     */

    if (objPtr->typePtr != &tclStringType) {

	if (objPtr->typePtr != NULL) {
	    if (objPtr->bytes == NULL) {
		objPtr->typePtr->updateStringProc(objPtr);
	    }
	    if ((objPtr->typePtr->freeIntRepProc) != NULL) {
		(*objPtr->typePtr->freeIntRepProc)(objPtr);
	    }
	}
	objPtr->typePtr = &tclStringType;

	/*
	 * Allocate enough space for the basic String structure.
	 */

	stringPtr = (String *) ckalloc(sizeof(String));
	stringPtr->numChars = -1;
	stringPtr->uallocated = 0;

	if (objPtr->bytes != NULL) {
	    stringPtr->allocated = objPtr->length;	    
 	    objPtr->bytes[objPtr->length] = 0;
	} else {
	    objPtr->length = 0;
	}
	SET_STRING(objPtr, stringPtr);
    }
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * UpdateStringOfString --
 *
 *	Update the string representation for an object whose internal
 *	representation is "String".
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	The object's string may be set by converting its Unicode
 *	represention to UTF format.
 *
 *----------------------------------------------------------------------
 */

static void
UpdateStringOfString(objPtr)
    Tcl_Obj *objPtr;		/* Object with string rep to update. */
{
    int i, length, size;
    Tcl_UniChar *unicode;
    char dummy[TCL_UTF_MAX];
    char *dst;
    String *stringPtr;

    stringPtr = GET_STRING(objPtr);
    if ((objPtr->bytes == NULL) || (stringPtr->allocated == 0)) {

	if (stringPtr->numChars <= 0) {

	    /*
	     * If there is no Unicode rep, or the string has 0 chars,
	     * then set the string rep to an empty string.
	     */

	    objPtr->bytes = tclEmptyStringRep;
	    objPtr->length = 0;
	    return;
	}

	unicode = stringPtr->unicode;
	length = stringPtr->numChars * sizeof(Tcl_UniChar);

	/*
	 * Translate the Unicode string to UTF.  "size" will hold the
	 * amount of space the UTF string needs.
	 */

	size = 0;
	for (i = 0; i < stringPtr->numChars; i++) {
	    size += Tcl_UniCharToUtf((int) unicode[i], dummy);
	}
	
	dst = (char *) ckalloc((unsigned) (size + 1));
	objPtr->bytes = dst;
	objPtr->length = size;
	stringPtr->allocated = size;

	for (i = 0; i < stringPtr->numChars; i++) {
	    dst += Tcl_UniCharToUtf(unicode[i], dst);
	}
	*dst = '\0';
    }
    return;
}

/*
 *----------------------------------------------------------------------
 *
 * FreeStringInternalRep --
 *
 *	Deallocate the storage associated with a String data object's
 *	internal representation.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Frees memory. 
 *
 *----------------------------------------------------------------------
 */

static void
FreeStringInternalRep(objPtr)
    Tcl_Obj *objPtr;		/* Object with internal rep to free. */
{
    ckfree((char *) GET_STRING(objPtr));
}