about summary refs log tree commit diff
path: root/posix/regex_internal.c
blob: b10588f1ccbb1992f97c617055a794f0c7c2e4d5 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
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
/* Extended regular expression matching and search library.
   Copyright (C) 2002-2018 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Isamu Hasegawa <isamu@yamato.ibm.com>.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

static void re_string_construct_common (const char *str, Idx len,
					re_string_t *pstr,
					RE_TRANSLATE_TYPE trans, bool icase,
					const re_dfa_t *dfa);
static re_dfastate_t *create_ci_newstate (const re_dfa_t *dfa,
					  const re_node_set *nodes,
					  re_hashval_t hash);
static re_dfastate_t *create_cd_newstate (const re_dfa_t *dfa,
					  const re_node_set *nodes,
					  unsigned int context,
					  re_hashval_t hash);
static reg_errcode_t re_string_realloc_buffers (re_string_t *pstr,
						Idx new_buf_len);
#ifdef RE_ENABLE_I18N
static void build_wcs_buffer (re_string_t *pstr);
static reg_errcode_t build_wcs_upper_buffer (re_string_t *pstr);
#endif /* RE_ENABLE_I18N */
static void build_upper_buffer (re_string_t *pstr);
static void re_string_translate_buffer (re_string_t *pstr);
static unsigned int re_string_context_at (const re_string_t *input, Idx idx,
					  int eflags) __attribute__ ((pure));

/* Functions for string operation.  */

/* This function allocate the buffers.  It is necessary to call
   re_string_reconstruct before using the object.  */

static reg_errcode_t
__attribute_warn_unused_result__
re_string_allocate (re_string_t *pstr, const char *str, Idx len, Idx init_len,
		    RE_TRANSLATE_TYPE trans, bool icase, const re_dfa_t *dfa)
{
  reg_errcode_t ret;
  Idx init_buf_len;

  /* Ensure at least one character fits into the buffers.  */
  if (init_len < dfa->mb_cur_max)
    init_len = dfa->mb_cur_max;
  init_buf_len = (len + 1 < init_len) ? len + 1: init_len;
  re_string_construct_common (str, len, pstr, trans, icase, dfa);

  ret = re_string_realloc_buffers (pstr, init_buf_len);
  if (BE (ret != REG_NOERROR, 0))
    return ret;

  pstr->word_char = dfa->word_char;
  pstr->word_ops_used = dfa->word_ops_used;
  pstr->mbs = pstr->mbs_allocated ? pstr->mbs : (unsigned char *) str;
  pstr->valid_len = (pstr->mbs_allocated || dfa->mb_cur_max > 1) ? 0 : len;
  pstr->valid_raw_len = pstr->valid_len;
  return REG_NOERROR;
}

/* This function allocate the buffers, and initialize them.  */

static reg_errcode_t
__attribute_warn_unused_result__
re_string_construct (re_string_t *pstr, const char *str, Idx len,
		     RE_TRANSLATE_TYPE trans, bool icase, const re_dfa_t *dfa)
{
  reg_errcode_t ret;
  memset (pstr, '\0', sizeof (re_string_t));
  re_string_construct_common (str, len, pstr, trans, icase, dfa);

  if (len > 0)
    {
      ret = re_string_realloc_buffers (pstr, len + 1);
      if (BE (ret != REG_NOERROR, 0))
	return ret;
    }
  pstr->mbs = pstr->mbs_allocated ? pstr->mbs : (unsigned char *) str;

  if (icase)
    {
#ifdef RE_ENABLE_I18N
      if (dfa->mb_cur_max > 1)
	{
	  while (1)
	    {
	      ret = build_wcs_upper_buffer (pstr);
	      if (BE (ret != REG_NOERROR, 0))
		return ret;
	      if (pstr->valid_raw_len >= len)
		break;
	      if (pstr->bufs_len > pstr->valid_len + dfa->mb_cur_max)
		break;
	      ret = re_string_realloc_buffers (pstr, pstr->bufs_len * 2);
	      if (BE (ret != REG_NOERROR, 0))
		return ret;
	    }
	}
      else
#endif /* RE_ENABLE_I18N  */
	build_upper_buffer (pstr);
    }
  else
    {
#ifdef RE_ENABLE_I18N
      if (dfa->mb_cur_max > 1)
	build_wcs_buffer (pstr);
      else
#endif /* RE_ENABLE_I18N  */
	{
	  if (trans != NULL)
	    re_string_translate_buffer (pstr);
	  else
	    {
	      pstr->valid_len = pstr->bufs_len;
	      pstr->valid_raw_len = pstr->bufs_len;
	    }
	}
    }

  return REG_NOERROR;
}

/* Helper functions for re_string_allocate, and re_string_construct.  */

static reg_errcode_t
__attribute_warn_unused_result__
re_string_realloc_buffers (re_string_t *pstr, Idx new_buf_len)
{
#ifdef RE_ENABLE_I18N
  if (pstr->mb_cur_max > 1)
    {
      wint_t *new_wcs;

      /* Avoid overflow in realloc.  */
      const size_t max_object_size = MAX (sizeof (wint_t), sizeof (Idx));
      if (BE (MIN (IDX_MAX, SIZE_MAX / max_object_size) < new_buf_len, 0))
	return REG_ESPACE;

      new_wcs = re_realloc (pstr->wcs, wint_t, new_buf_len);
      if (BE (new_wcs == NULL, 0))
	return REG_ESPACE;
      pstr->wcs = new_wcs;
      if (pstr->offsets != NULL)
	{
	  Idx *new_offsets = re_realloc (pstr->offsets, Idx, new_buf_len);
	  if (BE (new_offsets == NULL, 0))
	    return REG_ESPACE;
	  pstr->offsets = new_offsets;
	}
    }
#endif /* RE_ENABLE_I18N  */
  if (pstr->mbs_allocated)
    {
      unsigned char *new_mbs = re_realloc (pstr->mbs, unsigned char,
					   new_buf_len);
      if (BE (new_mbs == NULL, 0))
	return REG_ESPACE;
      pstr->mbs = new_mbs;
    }
  pstr->bufs_len = new_buf_len;
  return REG_NOERROR;
}


static void
re_string_construct_common (const char *str, Idx len, re_string_t *pstr,
			    RE_TRANSLATE_TYPE trans, bool icase,
			    const re_dfa_t *dfa)
{
  pstr->raw_mbs = (const unsigned char *) str;
  pstr->len = len;
  pstr->raw_len = len;
  pstr->trans = trans;
  pstr->icase = icase;
  pstr->mbs_allocated = (trans != NULL || icase);
  pstr->mb_cur_max = dfa->mb_cur_max;
  pstr->is_utf8 = dfa->is_utf8;
  pstr->map_notascii = dfa->map_notascii;
  pstr->stop = pstr->len;
  pstr->raw_stop = pstr->stop;
}

#ifdef RE_ENABLE_I18N

/* Build wide character buffer PSTR->WCS.
   If the byte sequence of the string are:
     <mb1>(0), <mb1>(1), <mb2>(0), <mb2>(1), <sb3>
   Then wide character buffer will be:
     <wc1>   , WEOF    , <wc2>   , WEOF    , <wc3>
   We use WEOF for padding, they indicate that the position isn't
   a first byte of a multibyte character.

   Note that this function assumes PSTR->VALID_LEN elements are already
   built and starts from PSTR->VALID_LEN.  */

static void
build_wcs_buffer (re_string_t *pstr)
{
#ifdef _LIBC
  unsigned char buf[MB_LEN_MAX];
  assert (MB_LEN_MAX >= pstr->mb_cur_max);
#else
  unsigned char buf[64];
#endif
  mbstate_t prev_st;
  Idx byte_idx, end_idx, remain_len;
  size_t mbclen;

  /* Build the buffers from pstr->valid_len to either pstr->len or
     pstr->bufs_len.  */
  end_idx = (pstr->bufs_len > pstr->len) ? pstr->len : pstr->bufs_len;
  for (byte_idx = pstr->valid_len; byte_idx < end_idx;)
    {
      wchar_t wc;
      const char *p;

      remain_len = end_idx - byte_idx;
      prev_st = pstr->cur_state;
      /* Apply the translation if we need.  */
      if (BE (pstr->trans != NULL, 0))
	{
	  int i, ch;

	  for (i = 0; i < pstr->mb_cur_max && i < remain_len; ++i)
	    {
	      ch = pstr->raw_mbs [pstr->raw_mbs_idx + byte_idx + i];
	      buf[i] = pstr->mbs[byte_idx + i] = pstr->trans[ch];
	    }
	  p = (const char *) buf;
	}
      else
	p = (const char *) pstr->raw_mbs + pstr->raw_mbs_idx + byte_idx;
      mbclen = __mbrtowc (&wc, p, remain_len, &pstr->cur_state);
      if (BE (mbclen == (size_t) -1 || mbclen == 0
	      || (mbclen == (size_t) -2 && pstr->bufs_len >= pstr->len), 0))
	{
	  /* We treat these cases as a singlebyte character.  */
	  mbclen = 1;
	  wc = (wchar_t) pstr->raw_mbs[pstr->raw_mbs_idx + byte_idx];
	  if (BE (pstr->trans != NULL, 0))
	    wc = pstr->trans[wc];
	  pstr->cur_state = prev_st;
	}
      else if (BE (mbclen == (size_t) -2, 0))
	{
	  /* The buffer doesn't have enough space, finish to build.  */
	  pstr->cur_state = prev_st;
	  break;
	}

      /* Write wide character and padding.  */
      pstr->wcs[byte_idx++] = wc;
      /* Write paddings.  */
      for (remain_len = byte_idx + mbclen - 1; byte_idx < remain_len ;)
	pstr->wcs[byte_idx++] = WEOF;
    }
  pstr->valid_len = byte_idx;
  pstr->valid_raw_len = byte_idx;
}

/* Build wide character buffer PSTR->WCS like build_wcs_buffer,
   but for REG_ICASE.  */

static reg_errcode_t
__attribute_warn_unused_result__
build_wcs_upper_buffer (re_string_t *pstr)
{
  mbstate_t prev_st;
  Idx src_idx, byte_idx, end_idx, remain_len;
  size_t mbclen;
#ifdef _LIBC
  char buf[MB_LEN_MAX];
  assert (MB_LEN_MAX >= pstr->mb_cur_max);
#else
  char buf[64];
#endif

  byte_idx = pstr->valid_len;
  end_idx = (pstr->bufs_len > pstr->len) ? pstr->len : pstr->bufs_len;

  /* The following optimization assumes that ASCII characters can be
     mapped to wide characters with a simple cast.  */
  if (! pstr->map_notascii && pstr->trans == NULL && !pstr->offsets_needed)
    {
      while (byte_idx < end_idx)
	{
	  wchar_t wc;

	  if (isascii (pstr->raw_mbs[pstr->raw_mbs_idx + byte_idx])
	      && mbsinit (&pstr->cur_state))
	    {
	      /* In case of a singlebyte character.  */
	      pstr->mbs[byte_idx]
		= toupper (pstr->raw_mbs[pstr->raw_mbs_idx + byte_idx]);
	      /* The next step uses the assumption that wchar_t is encoded
		 ASCII-safe: all ASCII values can be converted like this.  */
	      pstr->wcs[byte_idx] = (wchar_t) pstr->mbs[byte_idx];
	      ++byte_idx;
	      continue;
	    }

	  remain_len = end_idx - byte_idx;
	  prev_st = pstr->cur_state;
	  mbclen = __mbrtowc (&wc,
			      ((const char *) pstr->raw_mbs + pstr->raw_mbs_idx
			       + byte_idx), remain_len, &pstr->cur_state);
	  if (BE (0 < mbclen && mbclen < (size_t) -2, 1))
	    {
	      wchar_t wcu = __towupper (wc);
	      if (wcu != wc)
		{
		  size_t mbcdlen;

		  mbcdlen = __wcrtomb (buf, wcu, &prev_st);
		  if (BE (mbclen == mbcdlen, 1))
		    memcpy (pstr->mbs + byte_idx, buf, mbclen);
		  else
		    {
		      src_idx = byte_idx;
		      goto offsets_needed;
		    }
		}
	      else
		memcpy (pstr->mbs + byte_idx,
			pstr->raw_mbs + pstr->raw_mbs_idx + byte_idx, mbclen);
	      pstr->wcs[byte_idx++] = wcu;
	      /* Write paddings.  */
	      for (remain_len = byte_idx + mbclen - 1; byte_idx < remain_len ;)
		pstr->wcs[byte_idx++] = WEOF;
	    }
	  else if (mbclen == (size_t) -1 || mbclen == 0
		   || (mbclen == (size_t) -2 && pstr->bufs_len >= pstr->len))
	    {
	      /* It is an invalid character, an incomplete character
		 at the end of the string, or '\0'.  Just use the byte.  */
	      int ch = pstr->raw_mbs[pstr->raw_mbs_idx + byte_idx];
	      pstr->mbs[byte_idx] = ch;
	      /* And also cast it to wide char.  */
	      pstr->wcs[byte_idx++] = (wchar_t) ch;
	      if (BE (mbclen == (size_t) -1, 0))
		pstr->cur_state = prev_st;
	    }
	  else
	    {
	      /* The buffer doesn't have enough space, finish to build.  */
	      pstr->cur_state = prev_st;
	      break;
	    }
	}
      pstr->valid_len = byte_idx;
      pstr->valid_raw_len = byte_idx;
      return REG_NOERROR;
    }
  else
    for (src_idx = pstr->valid_raw_len; byte_idx < end_idx;)
      {
	wchar_t wc;
	const char *p;
      offsets_needed:
	remain_len = end_idx - byte_idx;
	prev_st = pstr->cur_state;
	if (BE (pstr->trans != NULL, 0))
	  {
	    int i, ch;

	    for (i = 0; i < pstr->mb_cur_max && i < remain_len; ++i)
	      {
		ch = pstr->raw_mbs [pstr->raw_mbs_idx + src_idx + i];
		buf[i] = pstr->trans[ch];
	      }
	    p = (const char *) buf;
	  }
	else
	  p = (const char *) pstr->raw_mbs + pstr->raw_mbs_idx + src_idx;
	mbclen = __mbrtowc (&wc, p, remain_len, &pstr->cur_state);
	if (BE (0 < mbclen && mbclen < (size_t) -2, 1))
	  {
	    wchar_t wcu = __towupper (wc);
	    if (wcu != wc)
	      {
		size_t mbcdlen;

		mbcdlen = __wcrtomb ((char *) buf, wcu, &prev_st);
		if (BE (mbclen == mbcdlen, 1))
		  memcpy (pstr->mbs + byte_idx, buf, mbclen);
		else if (mbcdlen != (size_t) -1)
		  {
		    size_t i;

		    if (byte_idx + mbcdlen > pstr->bufs_len)
		      {
			pstr->cur_state = prev_st;
			break;
		      }

		    if (pstr->offsets == NULL)
		      {
			pstr->offsets = re_malloc (Idx, pstr->bufs_len);

			if (pstr->offsets == NULL)
			  return REG_ESPACE;
		      }
		    if (!pstr->offsets_needed)
		      {
			for (i = 0; i < (size_t) byte_idx; ++i)
			  pstr->offsets[i] = i;
			pstr->offsets_needed = 1;
		      }

		    memcpy (pstr->mbs + byte_idx, buf, mbcdlen);
		    pstr->wcs[byte_idx] = wcu;
		    pstr->offsets[byte_idx] = src_idx;
		    for (i = 1; i < mbcdlen; ++i)
		      {
			pstr->offsets[byte_idx + i]
			  = src_idx + (i < mbclen ? i : mbclen - 1);
			pstr->wcs[byte_idx + i] = WEOF;
		      }
		    pstr->len += mbcdlen - mbclen;
		    if (pstr->raw_stop > src_idx)
		      pstr->stop += mbcdlen - mbclen;
		    end_idx = (pstr->bufs_len > pstr->len)
			      ? pstr->len : pstr->bufs_len;
		    byte_idx += mbcdlen;
		    src_idx += mbclen;
		    continue;
		  }
		else
		  memcpy (pstr->mbs + byte_idx, p, mbclen);
	      }
	    else
	      memcpy (pstr->mbs + byte_idx, p, mbclen);

	    if (BE (pstr->offsets_needed != 0, 0))
	      {
		size_t i;
		for (i = 0; i < mbclen; ++i)
		  pstr->offsets[byte_idx + i] = src_idx + i;
	      }
	    src_idx += mbclen;

	    pstr->wcs[byte_idx++] = wcu;
	    /* Write paddings.  */
	    for (remain_len = byte_idx + mbclen - 1; byte_idx < remain_len ;)
	      pstr->wcs[byte_idx++] = WEOF;
	  }
	else if (mbclen == (size_t) -1 || mbclen == 0
		 || (mbclen == (size_t) -2 && pstr->bufs_len >= pstr->len))
	  {
	    /* It is an invalid character or '\0'.  Just use the byte.  */
	    int ch = pstr->raw_mbs[pstr->raw_mbs_idx + src_idx];

	    if (BE (pstr->trans != NULL, 0))
	      ch = pstr->trans [ch];
	    pstr->mbs[byte_idx] = ch;

	    if (BE (pstr->offsets_needed != 0, 0))
	      pstr->offsets[byte_idx] = src_idx;
	    ++src_idx;

	    /* And also cast it to wide char.  */
	    pstr->wcs[byte_idx++] = (wchar_t) ch;
	    if (BE (mbclen == (size_t) -1, 0))
	      pstr->cur_state = prev_st;
	  }
	else
	  {
	    /* The buffer doesn't have enough space, finish to build.  */
	    pstr->cur_state = prev_st;
	    break;
	  }
      }
  pstr->valid_len = byte_idx;
  pstr->valid_raw_len = src_idx;
  return REG_NOERROR;
}

/* Skip characters until the index becomes greater than NEW_RAW_IDX.
   Return the index.  */

static Idx
re_string_skip_chars (re_string_t *pstr, Idx new_raw_idx, wint_t *last_wc)
{
  mbstate_t prev_st;
  Idx rawbuf_idx;
  size_t mbclen;
  wint_t wc = WEOF;

  /* Skip the characters which are not necessary to check.  */
  for (rawbuf_idx = pstr->raw_mbs_idx + pstr->valid_raw_len;
       rawbuf_idx < new_raw_idx;)
    {
      wchar_t wc2;
      Idx remain_len = pstr->raw_len - rawbuf_idx;
      prev_st = pstr->cur_state;
      mbclen = __mbrtowc (&wc2, (const char *) pstr->raw_mbs + rawbuf_idx,
			  remain_len, &pstr->cur_state);
      if (BE (mbclen == (size_t) -2 || mbclen == (size_t) -1 || mbclen == 0, 0))
	{
	  /* We treat these cases as a single byte character.  */
	  if (mbclen == 0 || remain_len == 0)
	    wc = L'\0';
	  else
	    wc = *(unsigned char *) (pstr->raw_mbs + rawbuf_idx);
	  mbclen = 1;
	  pstr->cur_state = prev_st;
	}
      else
	wc = wc2;
      /* Then proceed the next character.  */
      rawbuf_idx += mbclen;
    }
  *last_wc = wc;
  return rawbuf_idx;
}
#endif /* RE_ENABLE_I18N  */

/* Build the buffer PSTR->MBS, and apply the translation if we need.
   This function is used in case of REG_ICASE.  */

static void
build_upper_buffer (re_string_t *pstr)
{
  Idx char_idx, end_idx;
  end_idx = (pstr->bufs_len > pstr->len) ? pstr->len : pstr->bufs_len;

  for (char_idx = pstr->valid_len; char_idx < end_idx; ++char_idx)
    {
      int ch = pstr->raw_mbs[pstr->raw_mbs_idx + char_idx];
      if (BE (pstr->trans != NULL, 0))
	ch = pstr->trans[ch];
      pstr->mbs[char_idx] = toupper (ch);
    }
  pstr->valid_len = char_idx;
  pstr->valid_raw_len = char_idx;
}

/* Apply TRANS to the buffer in PSTR.  */

static void
re_string_translate_buffer (re_string_t *pstr)
{
  Idx buf_idx, end_idx;
  end_idx = (pstr->bufs_len > pstr->len) ? pstr->len : pstr->bufs_len;

  for (buf_idx = pstr->valid_len; buf_idx < end_idx; ++buf_idx)
    {
      int ch = pstr->raw_mbs[pstr->raw_mbs_idx + buf_idx];
      pstr->mbs[buf_idx] = pstr->trans[ch];
    }

  pstr->valid_len = buf_idx;
  pstr->valid_raw_len = buf_idx;
}

/* This function re-construct the buffers.
   Concretely, convert to wide character in case of pstr->mb_cur_max > 1,
   convert to upper case in case of REG_ICASE, apply translation.  */

static reg_errcode_t
__attribute_warn_unused_result__
re_string_reconstruct (re_string_t *pstr, Idx idx, int eflags)
{
  Idx offset;

  if (BE (pstr->raw_mbs_idx <= idx, 0))
    offset = idx - pstr->raw_mbs_idx;
  else
    {
      /* Reset buffer.  */
#ifdef RE_ENABLE_I18N
      if (pstr->mb_cur_max > 1)
	memset (&pstr->cur_state, '\0', sizeof (mbstate_t));
#endif /* RE_ENABLE_I18N */
      pstr->len = pstr->raw_len;
      pstr->stop = pstr->raw_stop;
      pstr->valid_len = 0;
      pstr->raw_mbs_idx = 0;
      pstr->valid_raw_len = 0;
      pstr->offsets_needed = 0;
      pstr->tip_context = ((eflags & REG_NOTBOL) ? CONTEXT_BEGBUF
			   : CONTEXT_NEWLINE | CONTEXT_BEGBUF);
      if (!pstr->mbs_allocated)
	pstr->mbs = (unsigned char *) pstr->raw_mbs;
      offset = idx;
    }

  if (BE (offset != 0, 1))
    {
      /* Should the already checked characters be kept?  */
      if (BE (offset < pstr->valid_raw_len, 1))
	{
	  /* Yes, move them to the front of the buffer.  */
#ifdef RE_ENABLE_I18N
	  if (BE (pstr->offsets_needed, 0))
	    {
	      Idx low = 0, high = pstr->valid_len, mid;
	      do
		{
		  mid = (high + low) / 2;
		  if (pstr->offsets[mid] > offset)
		    high = mid;
		  else if (pstr->offsets[mid] < offset)
		    low = mid + 1;
		  else
		    break;
		}
	      while (low < high);
	      if (pstr->offsets[mid] < offset)
		++mid;
	      pstr->tip_context = re_string_context_at (pstr, mid - 1,
							eflags);
	      /* This can be quite complicated, so handle specially
		 only the common and easy case where the character with
		 different length representation of lower and upper
		 case is present at or after offset.  */
	      if (pstr->valid_len > offset
		  && mid == offset && pstr->offsets[mid] == offset)
		{
		  memmove (pstr->wcs, pstr->wcs + offset,
			   (pstr->valid_len - offset) * sizeof (wint_t));
		  memmove (pstr->mbs, pstr->mbs + offset, pstr->valid_len - offset);
		  pstr->valid_len -= offset;
		  pstr->valid_raw_len -= offset;
		  for (low = 0; low < pstr->valid_len; low++)
		    pstr->offsets[low] = pstr->offsets[low + offset] - offset;
		}
	      else
		{
		  /* Otherwise, just find out how long the partial multibyte
		     character at offset is and fill it with WEOF/255.  */
		  pstr->len = pstr->raw_len - idx + offset;
		  pstr->stop = pstr->raw_stop - idx + offset;
		  pstr->offsets_needed = 0;
		  while (mid > 0 && pstr->offsets[mid - 1] == offset)
		    --mid;
		  while (mid < pstr->valid_len)
		    if (pstr->wcs[mid] != WEOF)
		      break;
		    else
		      ++mid;
		  if (mid == pstr->valid_len)
		    pstr->valid_len = 0;
		  else
		    {
		      pstr->valid_len = pstr->offsets[mid] - offset;
		      if (pstr->valid_len)
			{
			  for (low = 0; low < pstr->valid_len; ++low)
			    pstr->wcs[low] = WEOF;
			  memset (pstr->mbs, 255, pstr->valid_len);
			}
		    }
		  pstr->valid_raw_len = pstr->valid_len;
		}
	    }
	  else
#endif
	    {
	      pstr->tip_context = re_string_context_at (pstr, offset - 1,
							eflags);
#ifdef RE_ENABLE_I18N
	      if (pstr->mb_cur_max > 1)
		memmove (pstr->wcs, pstr->wcs + offset,
			 (pstr->valid_len - offset) * sizeof (wint_t));
#endif /* RE_ENABLE_I18N */
	      if (BE (pstr->mbs_allocated, 0))
		memmove (pstr->mbs, pstr->mbs + offset,
			 pstr->valid_len - offset);
	      pstr->valid_len -= offset;
	      pstr->valid_raw_len -= offset;
#if defined DEBUG && DEBUG
	      assert (pstr->valid_len > 0);
#endif
	    }
	}
      else
	{
#ifdef RE_ENABLE_I18N
	  /* No, skip all characters until IDX.  */
	  Idx prev_valid_len = pstr->valid_len;

	  if (BE (pstr->offsets_needed, 0))
	    {
	      pstr->len = pstr->raw_len - idx + offset;
	      pstr->stop = pstr->raw_stop - idx + offset;
	      pstr->offsets_needed = 0;
	    }
#endif
	  pstr->valid_len = 0;
#ifdef RE_ENABLE_I18N
	  if (pstr->mb_cur_max > 1)
	    {
	      Idx wcs_idx;
	      wint_t wc = WEOF;

	      if (pstr->is_utf8)
		{
		  const unsigned char *raw, *p, *end;

		  /* Special case UTF-8.  Multi-byte chars start with any
		     byte other than 0x80 - 0xbf.  */
		  raw = pstr->raw_mbs + pstr->raw_mbs_idx;
		  end = raw + (offset - pstr->mb_cur_max);
		  if (end < pstr->raw_mbs)
		    end = pstr->raw_mbs;
		  p = raw + offset - 1;
#ifdef _LIBC
		  /* We know the wchar_t encoding is UCS4, so for the simple
		     case, ASCII characters, skip the conversion step.  */
		  if (isascii (*p) && BE (pstr->trans == NULL, 1))
		    {
		      memset (&pstr->cur_state, '\0', sizeof (mbstate_t));
		      /* pstr->valid_len = 0; */
		      wc = (wchar_t) *p;
		    }
		  else
#endif
		    for (; p >= end; --p)
		      if ((*p & 0xc0) != 0x80)
			{
			  mbstate_t cur_state;
			  wchar_t wc2;
			  Idx mlen = raw + pstr->len - p;
			  unsigned char buf[6];
			  size_t mbclen;

			  const unsigned char *pp = p;
			  if (BE (pstr->trans != NULL, 0))
			    {
			      int i = mlen < 6 ? mlen : 6;
			      while (--i >= 0)
				buf[i] = pstr->trans[p[i]];
			      pp = buf;
			    }
			  /* XXX Don't use mbrtowc, we know which conversion
			     to use (UTF-8 -> UCS4).  */
			  memset (&cur_state, 0, sizeof (cur_state));
			  mbclen = __mbrtowc (&wc2, (const char *) pp, mlen,
					      &cur_state);
			  if (raw + offset - p <= mbclen
			      && mbclen < (size_t) -2)
			    {
			      memset (&pstr->cur_state, '\0',
				      sizeof (mbstate_t));
			      pstr->valid_len = mbclen - (raw + offset - p);
			      wc = wc2;
			    }
			  break;
			}
		}

	      if (wc == WEOF)
		pstr->valid_len = re_string_skip_chars (pstr, idx, &wc) - idx;
	      if (wc == WEOF)
		pstr->tip_context
		  = re_string_context_at (pstr, prev_valid_len - 1, eflags);
	      else
		pstr->tip_context = ((BE (pstr->word_ops_used != 0, 0)
				      && IS_WIDE_WORD_CHAR (wc))
				     ? CONTEXT_WORD
				     : ((IS_WIDE_NEWLINE (wc)
					 && pstr->newline_anchor)
					? CONTEXT_NEWLINE : 0));
	      if (BE (pstr->valid_len, 0))
		{
		  for (wcs_idx = 0; wcs_idx < pstr->valid_len; ++wcs_idx)
		    pstr->wcs[wcs_idx] = WEOF;
		  if (pstr->mbs_allocated)
		    memset (pstr->mbs, 255, pstr->valid_len);
		}
	      pstr->valid_raw_len = pstr->valid_len;
	    }
	  else
#endif /* RE_ENABLE_I18N */
	    {
	      int c = pstr->raw_mbs[pstr->raw_mbs_idx + offset - 1];
	      pstr->valid_raw_len = 0;
	      if (pstr->trans)
		c = pstr->trans[c];
	      pstr->tip_context = (bitset_contain (pstr->word_char, c)
				   ? CONTEXT_WORD
				   : ((IS_NEWLINE (c) && pstr->newline_anchor)
				      ? CONTEXT_NEWLINE : 0));
	    }
	}
      if (!BE (pstr->mbs_allocated, 0))
	pstr->mbs += offset;
    }
  pstr->raw_mbs_idx = idx;
  pstr->len -= offset;
  pstr->stop -= offset;

  /* Then build the buffers.  */
#ifdef RE_ENABLE_I18N
  if (pstr->mb_cur_max > 1)
    {
      if (pstr->icase)
	{
	  reg_errcode_t ret = build_wcs_upper_buffer (pstr);
	  if (BE (ret != REG_NOERROR, 0))
	    return ret;
	}
      else
	build_wcs_buffer (pstr);
    }
  else
#endif /* RE_ENABLE_I18N */
    if (BE (pstr->mbs_allocated, 0))
      {
	if (pstr->icase)
	  build_upper_buffer (pstr);
	else if (pstr->trans != NULL)
	  re_string_translate_buffer (pstr);
      }
    else
      pstr->valid_len = pstr->len;

  pstr->cur_idx = 0;
  return REG_NOERROR;
}

static unsigned char
__attribute__ ((pure))
re_string_peek_byte_case (const re_string_t *pstr, Idx idx)
{
  int ch;
  Idx off;

  /* Handle the common (easiest) cases first.  */
  if (BE (!pstr->mbs_allocated, 1))
    return re_string_peek_byte (pstr, idx);

#ifdef RE_ENABLE_I18N
  if (pstr->mb_cur_max > 1
      && ! re_string_is_single_byte_char (pstr, pstr->cur_idx + idx))
    return re_string_peek_byte (pstr, idx);
#endif

  off = pstr->cur_idx + idx;
#ifdef RE_ENABLE_I18N
  if (pstr->offsets_needed)
    off = pstr->offsets[off];
#endif

  ch = pstr->raw_mbs[pstr->raw_mbs_idx + off];

#ifdef RE_ENABLE_I18N
  /* Ensure that e.g. for tr_TR.UTF-8 BACKSLASH DOTLESS SMALL LETTER I
     this function returns CAPITAL LETTER I instead of first byte of
     DOTLESS SMALL LETTER I.  The latter would confuse the parser,
     since peek_byte_case doesn't advance cur_idx in any way.  */
  if (pstr->offsets_needed && !isascii (ch))
    return re_string_peek_byte (pstr, idx);
#endif

  return ch;
}

static unsigned char
re_string_fetch_byte_case (re_string_t *pstr)
{
  if (BE (!pstr->mbs_allocated, 1))
    return re_string_fetch_byte (pstr);

#ifdef RE_ENABLE_I18N
  if (pstr->offsets_needed)
    {
      Idx off;
      int ch;

      /* For tr_TR.UTF-8 [[:islower:]] there is
	 [[: CAPITAL LETTER I WITH DOT lower:]] in mbs.  Skip
	 in that case the whole multi-byte character and return
	 the original letter.  On the other side, with
	 [[: DOTLESS SMALL LETTER I return [[:I, as doing
	 anything else would complicate things too much.  */

      if (!re_string_first_byte (pstr, pstr->cur_idx))
	return re_string_fetch_byte (pstr);

      off = pstr->offsets[pstr->cur_idx];
      ch = pstr->raw_mbs[pstr->raw_mbs_idx + off];

      if (! isascii (ch))
	return re_string_fetch_byte (pstr);

      re_string_skip_bytes (pstr,
			    re_string_char_size_at (pstr, pstr->cur_idx));
      return ch;
    }
#endif

  return pstr->raw_mbs[pstr->raw_mbs_idx + pstr->cur_idx++];
}

static void
re_string_destruct (re_string_t *pstr)
{
#ifdef RE_ENABLE_I18N
  re_free (pstr->wcs);
  re_free (pstr->offsets);
#endif /* RE_ENABLE_I18N  */
  if (pstr->mbs_allocated)
    re_free (pstr->mbs);
}

/* Return the context at IDX in INPUT.  */

static unsigned int
re_string_context_at (const re_string_t *input, Idx idx, int eflags)
{
  int c;
  if (BE (idx < 0, 0))
    /* In this case, we use the value stored in input->tip_context,
       since we can't know the character in input->mbs[-1] here.  */
    return input->tip_context;
  if (BE (idx == input->len, 0))
    return ((eflags & REG_NOTEOL) ? CONTEXT_ENDBUF
	    : CONTEXT_NEWLINE | CONTEXT_ENDBUF);
#ifdef RE_ENABLE_I18N
  if (input->mb_cur_max > 1)
    {
      wint_t wc;
      Idx wc_idx = idx;
      while(input->wcs[wc_idx] == WEOF)
	{
#if defined DEBUG && DEBUG
	  /* It must not happen.  */
	  assert (wc_idx >= 0);
#endif
	  --wc_idx;
	  if (wc_idx < 0)
	    return input->tip_context;
	}
      wc = input->wcs[wc_idx];
      if (BE (input->word_ops_used != 0, 0) && IS_WIDE_WORD_CHAR (wc))
	return CONTEXT_WORD;
      return (IS_WIDE_NEWLINE (wc) && input->newline_anchor
	      ? CONTEXT_NEWLINE : 0);
    }
  else
#endif
    {
      c = re_string_byte_at (input, idx);
      if (bitset_contain (input->word_char, c))
	return CONTEXT_WORD;
      return IS_NEWLINE (c) && input->newline_anchor ? CONTEXT_NEWLINE : 0;
    }
}

/* Functions for set operation.  */

static reg_errcode_t
__attribute_warn_unused_result__
re_node_set_alloc (re_node_set *set, Idx size)
{
  set->alloc = size;
  set->nelem = 0;
  set->elems = re_malloc (Idx, size);
  if (BE (set->elems == NULL, 0) && (MALLOC_0_IS_NONNULL || size != 0))
    return REG_ESPACE;
  return REG_NOERROR;
}

static reg_errcode_t
__attribute_warn_unused_result__
re_node_set_init_1 (re_node_set *set, Idx elem)
{
  set->alloc = 1;
  set->nelem = 1;
  set->elems = re_malloc (Idx, 1);
  if (BE (set->elems == NULL, 0))
    {
      set->alloc = set->nelem = 0;
      return REG_ESPACE;
    }
  set->elems[0] = elem;
  return REG_NOERROR;
}

static reg_errcode_t
__attribute_warn_unused_result__
re_node_set_init_2 (re_node_set *set, Idx elem1, Idx elem2)
{
  set->alloc = 2;
  set->elems = re_malloc (Idx, 2);
  if (BE (set->elems == NULL, 0))
    return REG_ESPACE;
  if (elem1 == elem2)
    {
      set->nelem = 1;
      set->elems[0] = elem1;
    }
  else
    {
      set->nelem = 2;
      if (elem1 < elem2)
	{
	  set->elems[0] = elem1;
	  set->elems[1] = elem2;
	}
      else
	{
	  set->elems[0] = elem2;
	  set->elems[1] = elem1;
	}
    }
  return REG_NOERROR;
}

static reg_errcode_t
__attribute_warn_unused_result__
re_node_set_init_copy (re_node_set *dest, const re_node_set *src)
{
  dest->nelem = src->nelem;
  if (src->nelem > 0)
    {
      dest->alloc = dest->nelem;
      dest->elems = re_malloc (Idx, dest->alloc);
      if (BE (dest->elems == NULL, 0))
	{
	  dest->alloc = dest->nelem = 0;
	  return REG_ESPACE;
	}
      memcpy (dest->elems, src->elems, src->nelem * sizeof (Idx));
    }
  else
    re_node_set_init_empty (dest);
  return REG_NOERROR;
}

/* Calculate the intersection of the sets SRC1 and SRC2. And merge it to
   DEST. Return value indicate the error code or REG_NOERROR if succeeded.
   Note: We assume dest->elems is NULL, when dest->alloc is 0.  */

static reg_errcode_t
__attribute_warn_unused_result__
re_node_set_add_intersect (re_node_set *dest, const re_node_set *src1,
			   const re_node_set *src2)
{
  Idx i1, i2, is, id, delta, sbase;
  if (src1->nelem == 0 || src2->nelem == 0)
    return REG_NOERROR;

  /* We need dest->nelem + 2 * elems_in_intersection; this is a
     conservative estimate.  */
  if (src1->nelem + src2->nelem + dest->nelem > dest->alloc)
    {
      Idx new_alloc = src1->nelem + src2->nelem + dest->alloc;
      Idx *new_elems = re_realloc (dest->elems, Idx, new_alloc);
      if (BE (new_elems == NULL, 0))
	return REG_ESPACE;
      dest->elems = new_elems;
      dest->alloc = new_alloc;
    }

  /* Find the items in the intersection of SRC1 and SRC2, and copy
     into the top of DEST those that are not already in DEST itself.  */
  sbase = dest->nelem + src1->nelem + src2->nelem;
  i1 = src1->nelem - 1;
  i2 = src2->nelem - 1;
  id = dest->nelem - 1;
  for (;;)
    {
      if (src1->elems[i1] == src2->elems[i2])
	{
	  /* Try to find the item in DEST.  Maybe we could binary search?  */
	  while (id >= 0 && dest->elems[id] > src1->elems[i1])
	    --id;

	  if (id < 0 || dest->elems[id] != src1->elems[i1])
            dest->elems[--sbase] = src1->elems[i1];

	  if (--i1 < 0 || --i2 < 0)
	    break;
	}

      /* Lower the highest of the two items.  */
      else if (src1->elems[i1] < src2->elems[i2])
	{
	  if (--i2 < 0)
	    break;
	}
      else
	{
	  if (--i1 < 0)
	    break;
	}
    }

  id = dest->nelem - 1;
  is = dest->nelem + src1->nelem + src2->nelem - 1;
  delta = is - sbase + 1;

  /* Now copy.  When DELTA becomes zero, the remaining
     DEST elements are already in place; this is more or
     less the same loop that is in re_node_set_merge.  */
  dest->nelem += delta;
  if (delta > 0 && id >= 0)
    for (;;)
      {
	if (dest->elems[is] > dest->elems[id])
	  {
	    /* Copy from the top.  */
	    dest->elems[id + delta--] = dest->elems[is--];
	    if (delta == 0)
	      break;
	  }
	else
	  {
	    /* Slide from the bottom.  */
	    dest->elems[id + delta] = dest->elems[id];
	    if (--id < 0)
	      break;
	  }
      }

  /* Copy remaining SRC elements.  */
  memcpy (dest->elems, dest->elems + sbase, delta * sizeof (Idx));

  return REG_NOERROR;
}

/* Calculate the union set of the sets SRC1 and SRC2. And store it to
   DEST. Return value indicate the error code or REG_NOERROR if succeeded.  */

static reg_errcode_t
__attribute_warn_unused_result__
re_node_set_init_union (re_node_set *dest, const re_node_set *src1,
			const re_node_set *src2)
{
  Idx i1, i2, id;
  if (src1 != NULL && src1->nelem > 0 && src2 != NULL && src2->nelem > 0)
    {
      dest->alloc = src1->nelem + src2->nelem;
      dest->elems = re_malloc (Idx, dest->alloc);
      if (BE (dest->elems == NULL, 0))
	return REG_ESPACE;
    }
  else
    {
      if (src1 != NULL && src1->nelem > 0)
	return re_node_set_init_copy (dest, src1);
      else if (src2 != NULL && src2->nelem > 0)
	return re_node_set_init_copy (dest, src2);
      else
	re_node_set_init_empty (dest);
      return REG_NOERROR;
    }
  for (i1 = i2 = id = 0 ; i1 < src1->nelem && i2 < src2->nelem ;)
    {
      if (src1->elems[i1] > src2->elems[i2])
	{
	  dest->elems[id++] = src2->elems[i2++];
	  continue;
	}
      if (src1->elems[i1] == src2->elems[i2])
	++i2;
      dest->elems[id++] = src1->elems[i1++];
    }
  if (i1 < src1->nelem)
    {
      memcpy (dest->elems + id, src1->elems + i1,
	     (src1->nelem - i1) * sizeof (Idx));
      id += src1->nelem - i1;
    }
  else if (i2 < src2->nelem)
    {
      memcpy (dest->elems + id, src2->elems + i2,
	     (src2->nelem - i2) * sizeof (Idx));
      id += src2->nelem - i2;
    }
  dest->nelem = id;
  return REG_NOERROR;
}

/* Calculate the union set of the sets DEST and SRC. And store it to
   DEST. Return value indicate the error code or REG_NOERROR if succeeded.  */

static reg_errcode_t
__attribute_warn_unused_result__
re_node_set_merge (re_node_set *dest, const re_node_set *src)
{
  Idx is, id, sbase, delta;
  if (src == NULL || src->nelem == 0)
    return REG_NOERROR;
  if (dest->alloc < 2 * src->nelem + dest->nelem)
    {
      Idx new_alloc = 2 * (src->nelem + dest->alloc);
      Idx *new_buffer = re_realloc (dest->elems, Idx, new_alloc);
      if (BE (new_buffer == NULL, 0))
	return REG_ESPACE;
      dest->elems = new_buffer;
      dest->alloc = new_alloc;
    }

  if (BE (dest->nelem == 0, 0))
    {
      dest->nelem = src->nelem;
      memcpy (dest->elems, src->elems, src->nelem * sizeof (Idx));
      return REG_NOERROR;
    }

  /* Copy into the top of DEST the items of SRC that are not
     found in DEST.  Maybe we could binary search in DEST?  */
  for (sbase = dest->nelem + 2 * src->nelem,
       is = src->nelem - 1, id = dest->nelem - 1; is >= 0 && id >= 0; )
    {
      if (dest->elems[id] == src->elems[is])
	is--, id--;
      else if (dest->elems[id] < src->elems[is])
	dest->elems[--sbase] = src->elems[is--];
      else /* if (dest->elems[id] > src->elems[is]) */
	--id;
    }

  if (is >= 0)
    {
      /* If DEST is exhausted, the remaining items of SRC must be unique.  */
      sbase -= is + 1;
      memcpy (dest->elems + sbase, src->elems, (is + 1) * sizeof (Idx));
    }

  id = dest->nelem - 1;
  is = dest->nelem + 2 * src->nelem - 1;
  delta = is - sbase + 1;
  if (delta == 0)
    return REG_NOERROR;

  /* Now copy.  When DELTA becomes zero, the remaining
     DEST elements are already in place.  */
  dest->nelem += delta;
  for (;;)
    {
      if (dest->elems[is] > dest->elems[id])
	{
	  /* Copy from the top.  */
	  dest->elems[id + delta--] = dest->elems[is--];
	  if (delta == 0)
	    break;
	}
      else
	{
	  /* Slide from the bottom.  */
	  dest->elems[id + delta] = dest->elems[id];
	  if (--id < 0)
	    {
	      /* Copy remaining SRC elements.  */
	      memcpy (dest->elems, dest->elems + sbase,
		      delta * sizeof (Idx));
	      break;
	    }
	}
    }

  return REG_NOERROR;
}

/* Insert the new element ELEM to the re_node_set* SET.
   SET should not already have ELEM.
   Return true if successful.  */

static bool
__attribute_warn_unused_result__
re_node_set_insert (re_node_set *set, Idx elem)
{
  Idx idx;
  /* In case the set is empty.  */
  if (set->alloc == 0)
    return BE (re_node_set_init_1 (set, elem) == REG_NOERROR, 1);

  if (BE (set->nelem, 0) == 0)
    {
      /* We already guaranteed above that set->alloc != 0.  */
      set->elems[0] = elem;
      ++set->nelem;
      return true;
    }

  /* Realloc if we need.  */
  if (set->alloc == set->nelem)
    {
      Idx *new_elems;
      set->alloc = set->alloc * 2;
      new_elems = re_realloc (set->elems, Idx, set->alloc);
      if (BE (new_elems == NULL, 0))
	return false;
      set->elems = new_elems;
    }

  /* Move the elements which follows the new element.  Test the
     first element separately to skip a check in the inner loop.  */
  if (elem < set->elems[0])
    {
      idx = 0;
      for (idx = set->nelem; idx > 0; idx--)
	set->elems[idx] = set->elems[idx - 1];
    }
  else
    {
      for (idx = set->nelem; set->elems[idx - 1] > elem; idx--)
	set->elems[idx] = set->elems[idx - 1];
    }

  /* Insert the new element.  */
  set->elems[idx] = elem;
  ++set->nelem;
  return true;
}

/* Insert the new element ELEM to the re_node_set* SET.
   SET should not already have any element greater than or equal to ELEM.
   Return true if successful.  */

static bool
__attribute_warn_unused_result__
re_node_set_insert_last (re_node_set *set, Idx elem)
{
  /* Realloc if we need.  */
  if (set->alloc == set->nelem)
    {
      Idx *new_elems;
      set->alloc = (set->alloc + 1) * 2;
      new_elems = re_realloc (set->elems, Idx, set->alloc);
      if (BE (new_elems == NULL, 0))
	return false;
      set->elems = new_elems;
    }

  /* Insert the new element.  */
  set->elems[set->nelem++] = elem;
  return true;
}

/* Compare two node sets SET1 and SET2.
   Return true if SET1 and SET2 are equivalent.  */

static bool
__attribute__ ((pure))
re_node_set_compare (const re_node_set *set1, const re_node_set *set2)
{
  Idx i;
  if (set1 == NULL || set2 == NULL || set1->nelem != set2->nelem)
    return false;
  for (i = set1->nelem ; --i >= 0 ; )
    if (set1->elems[i] != set2->elems[i])
      return false;
  return true;
}

/* Return (idx + 1) if SET contains the element ELEM, return 0 otherwise.  */

static Idx
__attribute__ ((pure))
re_node_set_contains (const re_node_set *set, Idx elem)
{
  __re_size_t idx, right, mid;
  if (set->nelem <= 0)
    return 0;

  /* Binary search the element.  */
  idx = 0;
  right = set->nelem - 1;
  while (idx < right)
    {
      mid = (idx + right) / 2;
      if (set->elems[mid] < elem)
	idx = mid + 1;
      else
	right = mid;
    }
  return set->elems[idx] == elem ? idx + 1 : 0;
}

static void
re_node_set_remove_at (re_node_set *set, Idx idx)
{
  if (idx < 0 || idx >= set->nelem)
    return;
  --set->nelem;
  for (; idx < set->nelem; idx++)
    set->elems[idx] = set->elems[idx + 1];
}


/* Add the token TOKEN to dfa->nodes, and return the index of the token.
   Or return -1 if an error occurred.  */

static Idx
re_dfa_add_node (re_dfa_t *dfa, re_token_t token)
{
  if (BE (dfa->nodes_len >= dfa->nodes_alloc, 0))
    {
      size_t new_nodes_alloc = dfa->nodes_alloc * 2;
      Idx *new_nexts, *new_indices;
      re_node_set *new_edests, *new_eclosures;
      re_token_t *new_nodes;

      /* Avoid overflows in realloc.  */
      const size_t max_object_size = MAX (sizeof (re_token_t),
					  MAX (sizeof (re_node_set),
					       sizeof (Idx)));
      if (BE (MIN (IDX_MAX, SIZE_MAX / max_object_size) < new_nodes_alloc, 0))
	return -1;

      new_nodes = re_realloc (dfa->nodes, re_token_t, new_nodes_alloc);
      if (BE (new_nodes == NULL, 0))
	return -1;
      dfa->nodes = new_nodes;
      new_nexts = re_realloc (dfa->nexts, Idx, new_nodes_alloc);
      new_indices = re_realloc (dfa->org_indices, Idx, new_nodes_alloc);
      new_edests = re_realloc (dfa->edests, re_node_set, new_nodes_alloc);
      new_eclosures = re_realloc (dfa->eclosures, re_node_set, new_nodes_alloc);
      if (BE (new_nexts == NULL || new_indices == NULL
	      || new_edests == NULL || new_eclosures == NULL, 0))
	{
	   re_free (new_nexts);
	   re_free (new_indices);
	   re_free (new_edests);
	   re_free (new_eclosures);
	   return -1;
	}
      dfa->nexts = new_nexts;
      dfa->org_indices = new_indices;
      dfa->edests = new_edests;
      dfa->eclosures = new_eclosures;
      dfa->nodes_alloc = new_nodes_alloc;
    }
  dfa->nodes[dfa->nodes_len] = token;
  dfa->nodes[dfa->nodes_len].constraint = 0;
#ifdef RE_ENABLE_I18N
  dfa->nodes[dfa->nodes_len].accept_mb =
    ((token.type == OP_PERIOD && dfa->mb_cur_max > 1)
     || token.type == COMPLEX_BRACKET);
#endif
  dfa->nexts[dfa->nodes_len] = -1;
  re_node_set_init_empty (dfa->edests + dfa->nodes_len);
  re_node_set_init_empty (dfa->eclosures + dfa->nodes_len);
  return dfa->nodes_len++;
}

static re_hashval_t
calc_state_hash (const re_node_set *nodes, unsigned int context)
{
  re_hashval_t hash = nodes->nelem + context;
  Idx i;
  for (i = 0 ; i < nodes->nelem ; i++)
    hash += nodes->elems[i];
  return hash;
}

/* Search for the state whose node_set is equivalent to NODES.
   Return the pointer to the state, if we found it in the DFA.
   Otherwise create the new one and return it.  In case of an error
   return NULL and set the error code in ERR.
   Note: - We assume NULL as the invalid state, then it is possible that
	   return value is NULL and ERR is REG_NOERROR.
	 - We never return non-NULL value in case of any errors, it is for
	   optimization.  */

static re_dfastate_t *
__attribute_warn_unused_result__
re_acquire_state (reg_errcode_t *err, const re_dfa_t *dfa,
		  const re_node_set *nodes)
{
  re_hashval_t hash;
  re_dfastate_t *new_state;
  struct re_state_table_entry *spot;
  Idx i;
#if defined GCC_LINT || defined lint
  /* Suppress bogus uninitialized-variable warnings.  */
  *err = REG_NOERROR;
#endif
  if (BE (nodes->nelem == 0, 0))
    {
      *err = REG_NOERROR;
      return NULL;
    }
  hash = calc_state_hash (nodes, 0);
  spot = dfa->state_table + (hash & dfa->state_hash_mask);

  for (i = 0 ; i < spot->num ; i++)
    {
      re_dfastate_t *state = spot->array[i];
      if (hash != state->hash)
	continue;
      if (re_node_set_compare (&state->nodes, nodes))
	return state;
    }

  /* There are no appropriate state in the dfa, create the new one.  */
  new_state = create_ci_newstate (dfa, nodes, hash);
  if (BE (new_state == NULL, 0))
    *err = REG_ESPACE;

  return new_state;
}

/* Search for the state whose node_set is equivalent to NODES and
   whose context is equivalent to CONTEXT.
   Return the pointer to the state, if we found it in the DFA.
   Otherwise create the new one and return it.  In case of an error
   return NULL and set the error code in ERR.
   Note: - We assume NULL as the invalid state, then it is possible that
	   return value is NULL and ERR is REG_NOERROR.
	 - We never return non-NULL value in case of any errors, it is for
	   optimization.  */

static re_dfastate_t *
__attribute_warn_unused_result__
re_acquire_state_context (reg_errcode_t *err, const re_dfa_t *dfa,
			  const re_node_set *nodes, unsigned int context)
{
  re_hashval_t hash;
  re_dfastate_t *new_state;
  struct re_state_table_entry *spot;
  Idx i;
#if defined GCC_LINT || defined lint
  /* Suppress bogus uninitialized-variable warnings.  */
  *err = REG_NOERROR;
#endif
  if (nodes->nelem == 0)
    {
      *err = REG_NOERROR;
      return NULL;
    }
  hash = calc_state_hash (nodes, context);
  spot = dfa->state_table + (hash & dfa->state_hash_mask);

  for (i = 0 ; i < spot->num ; i++)
    {
      re_dfastate_t *state = spot->array[i];
      if (state->hash == hash
	  && state->context == context
	  && re_node_set_compare (state->entrance_nodes, nodes))
	return state;
    }
  /* There are no appropriate state in 'dfa', create the new one.  */
  new_state = create_cd_newstate (dfa, nodes, context, hash);
  if (BE (new_state == NULL, 0))
    *err = REG_ESPACE;

  return new_state;
}

/* Finish initialization of the new state NEWSTATE, and using its hash value
   HASH put in the appropriate bucket of DFA's state table.  Return value
   indicates the error code if failed.  */

static reg_errcode_t
__attribute_warn_unused_result__
register_state (const re_dfa_t *dfa, re_dfastate_t *newstate,
		re_hashval_t hash)
{
  struct re_state_table_entry *spot;
  reg_errcode_t err;
  Idx i;

  newstate->hash = hash;
  err = re_node_set_alloc (&newstate->non_eps_nodes, newstate->nodes.nelem);
  if (BE (err != REG_NOERROR, 0))
    return REG_ESPACE;
  for (i = 0; i < newstate->nodes.nelem; i++)
    {
      Idx elem = newstate->nodes.elems[i];
      if (!IS_EPSILON_NODE (dfa->nodes[elem].type))
	if (! re_node_set_insert_last (&newstate->non_eps_nodes, elem))
	  return REG_ESPACE;
    }

  spot = dfa->state_table + (hash & dfa->state_hash_mask);
  if (BE (spot->alloc <= spot->num, 0))
    {
      Idx new_alloc = 2 * spot->num + 2;
      re_dfastate_t **new_array = re_realloc (spot->array, re_dfastate_t *,
					      new_alloc);
      if (BE (new_array == NULL, 0))
	return REG_ESPACE;
      spot->array = new_array;
      spot->alloc = new_alloc;
    }
  spot->array[spot->num++] = newstate;
  return REG_NOERROR;
}

static void
free_state (re_dfastate_t *state)
{
  re_node_set_free (&state->non_eps_nodes);
  re_node_set_free (&state->inveclosure);
  if (state->entrance_nodes != &state->nodes)
    {
      re_node_set_free (state->entrance_nodes);
      re_free (state->entrance_nodes);
    }
  re_node_set_free (&state->nodes);
  re_free (state->word_trtable);
  re_free (state->trtable);
  re_free (state);
}

/* Create the new state which is independent of contexts.
   Return the new state if succeeded, otherwise return NULL.  */

static re_dfastate_t *
__attribute_warn_unused_result__
create_ci_newstate (const re_dfa_t *dfa, const re_node_set *nodes,
		    re_hashval_t hash)
{
  Idx i;
  reg_errcode_t err;
  re_dfastate_t *newstate;

  newstate = (re_dfastate_t *) calloc (sizeof (re_dfastate_t), 1);
  if (BE (newstate == NULL, 0))
    return NULL;
  err = re_node_set_init_copy (&newstate->nodes, nodes);
  if (BE (err != REG_NOERROR, 0))
    {
      re_free (newstate);
      return NULL;
    }

  newstate->entrance_nodes = &newstate->nodes;
  for (i = 0 ; i < nodes->nelem ; i++)
    {
      re_token_t *node = dfa->nodes + nodes->elems[i];
      re_token_type_t type = node->type;
      if (type == CHARACTER && !node->constraint)
	continue;
#ifdef RE_ENABLE_I18N
      newstate->accept_mb |= node->accept_mb;
#endif /* RE_ENABLE_I18N */

      /* If the state has the halt node, the state is a halt state.  */
      if (type == END_OF_RE)
	newstate->halt = 1;
      else if (type == OP_BACK_REF)
	newstate->has_backref = 1;
      else if (type == ANCHOR || node->constraint)
	newstate->has_constraint = 1;
    }
  err = register_state (dfa, newstate, hash);
  if (BE (err != REG_NOERROR, 0))
    {
      free_state (newstate);
      newstate = NULL;
    }
  return newstate;
}

/* Create the new state which is depend on the context CONTEXT.
   Return the new state if succeeded, otherwise return NULL.  */

static re_dfastate_t *
__attribute_warn_unused_result__
create_cd_newstate (const re_dfa_t *dfa, const re_node_set *nodes,
		    unsigned int context, re_hashval_t hash)
{
  Idx i, nctx_nodes = 0;
  reg_errcode_t err;
  re_dfastate_t *newstate;

  newstate = (re_dfastate_t *) calloc (sizeof (re_dfastate_t), 1);
  if (BE (newstate == NULL, 0))
    return NULL;
  err = re_node_set_init_copy (&newstate->nodes, nodes);
  if (BE (err != REG_NOERROR, 0))
    {
      re_free (newstate);
      return NULL;
    }

  newstate->context = context;
  newstate->entrance_nodes = &newstate->nodes;

  for (i = 0 ; i < nodes->nelem ; i++)
    {
      re_token_t *node = dfa->nodes + nodes->elems[i];
      re_token_type_t type = node->type;
      unsigned int constraint = node->constraint;

      if (type == CHARACTER && !constraint)
	continue;
#ifdef RE_ENABLE_I18N
      newstate->accept_mb |= node->accept_mb;
#endif /* RE_ENABLE_I18N */

      /* If the state has the halt node, the state is a halt state.  */
      if (type == END_OF_RE)
	newstate->halt = 1;
      else if (type == OP_BACK_REF)
	newstate->has_backref = 1;

      if (constraint)
	{
	  if (newstate->entrance_nodes == &newstate->nodes)
	    {
	      newstate->entrance_nodes = re_malloc (re_node_set, 1);
	      if (BE (newstate->entrance_nodes == NULL, 0))
		{
		  free_state (newstate);
		  return NULL;
		}
	      if (re_node_set_init_copy (newstate->entrance_nodes, nodes)
		  != REG_NOERROR)
		return NULL;
	      nctx_nodes = 0;
	      newstate->has_constraint = 1;
	    }

	  if (NOT_SATISFY_PREV_CONSTRAINT (constraint,context))
	    {
	      re_node_set_remove_at (&newstate->nodes, i - nctx_nodes);
	      ++nctx_nodes;
	    }
	}
    }
  err = register_state (dfa, newstate, hash);
  if (BE (err != REG_NOERROR, 0))
    {
      free_state (newstate);
      newstate = NULL;
    }
  return  newstate;
}