This file is indexed.

/usr/include/mozjs-52/unicode/regex.h is in libmozjs-52-dev 52.3.1-7fakesync1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

   1
   2
   3
   4
   5
   6
   7
   8
   9
  10
  11
  12
  13
  14
  15
  16
  17
  18
  19
  20
  21
  22
  23
  24
  25
  26
  27
  28
  29
  30
  31
  32
  33
  34
  35
  36
  37
  38
  39
  40
  41
  42
  43
  44
  45
  46
  47
  48
  49
  50
  51
  52
  53
  54
  55
  56
  57
  58
  59
  60
  61
  62
  63
  64
  65
  66
  67
  68
  69
  70
  71
  72
  73
  74
  75
  76
  77
  78
  79
  80
  81
  82
  83
  84
  85
  86
  87
  88
  89
  90
  91
  92
  93
  94
  95
  96
  97
  98
  99
 100
 101
 102
 103
 104
 105
 106
 107
 108
 109
 110
 111
 112
 113
 114
 115
 116
 117
 118
 119
 120
 121
 122
 123
 124
 125
 126
 127
 128
 129
 130
 131
 132
 133
 134
 135
 136
 137
 138
 139
 140
 141
 142
 143
 144
 145
 146
 147
 148
 149
 150
 151
 152
 153
 154
 155
 156
 157
 158
 159
 160
 161
 162
 163
 164
 165
 166
 167
 168
 169
 170
 171
 172
 173
 174
 175
 176
 177
 178
 179
 180
 181
 182
 183
 184
 185
 186
 187
 188
 189
 190
 191
 192
 193
 194
 195
 196
 197
 198
 199
 200
 201
 202
 203
 204
 205
 206
 207
 208
 209
 210
 211
 212
 213
 214
 215
 216
 217
 218
 219
 220
 221
 222
 223
 224
 225
 226
 227
 228
 229
 230
 231
 232
 233
 234
 235
 236
 237
 238
 239
 240
 241
 242
 243
 244
 245
 246
 247
 248
 249
 250
 251
 252
 253
 254
 255
 256
 257
 258
 259
 260
 261
 262
 263
 264
 265
 266
 267
 268
 269
 270
 271
 272
 273
 274
 275
 276
 277
 278
 279
 280
 281
 282
 283
 284
 285
 286
 287
 288
 289
 290
 291
 292
 293
 294
 295
 296
 297
 298
 299
 300
 301
 302
 303
 304
 305
 306
 307
 308
 309
 310
 311
 312
 313
 314
 315
 316
 317
 318
 319
 320
 321
 322
 323
 324
 325
 326
 327
 328
 329
 330
 331
 332
 333
 334
 335
 336
 337
 338
 339
 340
 341
 342
 343
 344
 345
 346
 347
 348
 349
 350
 351
 352
 353
 354
 355
 356
 357
 358
 359
 360
 361
 362
 363
 364
 365
 366
 367
 368
 369
 370
 371
 372
 373
 374
 375
 376
 377
 378
 379
 380
 381
 382
 383
 384
 385
 386
 387
 388
 389
 390
 391
 392
 393
 394
 395
 396
 397
 398
 399
 400
 401
 402
 403
 404
 405
 406
 407
 408
 409
 410
 411
 412
 413
 414
 415
 416
 417
 418
 419
 420
 421
 422
 423
 424
 425
 426
 427
 428
 429
 430
 431
 432
 433
 434
 435
 436
 437
 438
 439
 440
 441
 442
 443
 444
 445
 446
 447
 448
 449
 450
 451
 452
 453
 454
 455
 456
 457
 458
 459
 460
 461
 462
 463
 464
 465
 466
 467
 468
 469
 470
 471
 472
 473
 474
 475
 476
 477
 478
 479
 480
 481
 482
 483
 484
 485
 486
 487
 488
 489
 490
 491
 492
 493
 494
 495
 496
 497
 498
 499
 500
 501
 502
 503
 504
 505
 506
 507
 508
 509
 510
 511
 512
 513
 514
 515
 516
 517
 518
 519
 520
 521
 522
 523
 524
 525
 526
 527
 528
 529
 530
 531
 532
 533
 534
 535
 536
 537
 538
 539
 540
 541
 542
 543
 544
 545
 546
 547
 548
 549
 550
 551
 552
 553
 554
 555
 556
 557
 558
 559
 560
 561
 562
 563
 564
 565
 566
 567
 568
 569
 570
 571
 572
 573
 574
 575
 576
 577
 578
 579
 580
 581
 582
 583
 584
 585
 586
 587
 588
 589
 590
 591
 592
 593
 594
 595
 596
 597
 598
 599
 600
 601
 602
 603
 604
 605
 606
 607
 608
 609
 610
 611
 612
 613
 614
 615
 616
 617
 618
 619
 620
 621
 622
 623
 624
 625
 626
 627
 628
 629
 630
 631
 632
 633
 634
 635
 636
 637
 638
 639
 640
 641
 642
 643
 644
 645
 646
 647
 648
 649
 650
 651
 652
 653
 654
 655
 656
 657
 658
 659
 660
 661
 662
 663
 664
 665
 666
 667
 668
 669
 670
 671
 672
 673
 674
 675
 676
 677
 678
 679
 680
 681
 682
 683
 684
 685
 686
 687
 688
 689
 690
 691
 692
 693
 694
 695
 696
 697
 698
 699
 700
 701
 702
 703
 704
 705
 706
 707
 708
 709
 710
 711
 712
 713
 714
 715
 716
 717
 718
 719
 720
 721
 722
 723
 724
 725
 726
 727
 728
 729
 730
 731
 732
 733
 734
 735
 736
 737
 738
 739
 740
 741
 742
 743
 744
 745
 746
 747
 748
 749
 750
 751
 752
 753
 754
 755
 756
 757
 758
 759
 760
 761
 762
 763
 764
 765
 766
 767
 768
 769
 770
 771
 772
 773
 774
 775
 776
 777
 778
 779
 780
 781
 782
 783
 784
 785
 786
 787
 788
 789
 790
 791
 792
 793
 794
 795
 796
 797
 798
 799
 800
 801
 802
 803
 804
 805
 806
 807
 808
 809
 810
 811
 812
 813
 814
 815
 816
 817
 818
 819
 820
 821
 822
 823
 824
 825
 826
 827
 828
 829
 830
 831
 832
 833
 834
 835
 836
 837
 838
 839
 840
 841
 842
 843
 844
 845
 846
 847
 848
 849
 850
 851
 852
 853
 854
 855
 856
 857
 858
 859
 860
 861
 862
 863
 864
 865
 866
 867
 868
 869
 870
 871
 872
 873
 874
 875
 876
 877
 878
 879
 880
 881
 882
 883
 884
 885
 886
 887
 888
 889
 890
 891
 892
 893
 894
 895
 896
 897
 898
 899
 900
 901
 902
 903
 904
 905
 906
 907
 908
 909
 910
 911
 912
 913
 914
 915
 916
 917
 918
 919
 920
 921
 922
 923
 924
 925
 926
 927
 928
 929
 930
 931
 932
 933
 934
 935
 936
 937
 938
 939
 940
 941
 942
 943
 944
 945
 946
 947
 948
 949
 950
 951
 952
 953
 954
 955
 956
 957
 958
 959
 960
 961
 962
 963
 964
 965
 966
 967
 968
 969
 970
 971
 972
 973
 974
 975
 976
 977
 978
 979
 980
 981
 982
 983
 984
 985
 986
 987
 988
 989
 990
 991
 992
 993
 994
 995
 996
 997
 998
 999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
// Copyright (C) 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
**********************************************************************
*   Copyright (C) 2002-2016, International Business Machines
*   Corporation and others.  All Rights Reserved.
**********************************************************************
*   file name:  regex.h
*   encoding:   US-ASCII
*   indentation:4
*
*   created on: 2002oct22
*   created by: Andy Heninger
*
*   ICU Regular Expressions, API for C++
*/

#ifndef REGEX_H
#define REGEX_H

//#define REGEX_DEBUG

/**
 * \file
 * \brief  C++ API:  Regular Expressions
 *
 * <h2>Regular Expression API</h2>
 *
 * <p>The ICU API for processing regular expressions consists of two classes,
 *  <code>RegexPattern</code> and <code>RegexMatcher</code>.
 *  <code>RegexPattern</code> objects represent a pre-processed, or compiled
 *  regular expression.  They are created from a regular expression pattern string,
 *  and can be used to create <code>RegexMatcher</code> objects for the pattern.</p>
 *
 * <p>Class <code>RegexMatcher</code> bundles together a regular expression
 *  pattern and a target string to which the search pattern will be applied.
 *  <code>RegexMatcher</code> includes API for doing plain find or search
 *  operations, for search and replace operations, and for obtaining detailed
 *  information about bounds of a match. </p>
 *
 * <p>Note that by constructing <code>RegexMatcher</code> objects directly from regular
 * expression pattern strings application code can be simplified and the explicit
 * need for <code>RegexPattern</code> objects can usually be eliminated.
 * </p>
 */

#include "unicode/utypes.h"

#if !UCONFIG_NO_REGULAR_EXPRESSIONS

#include "unicode/uobject.h"
#include "unicode/unistr.h"
#include "unicode/utext.h"
#include "unicode/parseerr.h"

#include "unicode/uregex.h"

// Forward Declarations

struct UHashtable;

U_NAMESPACE_BEGIN

struct Regex8BitSet;
class  RegexCImpl;
class  RegexMatcher;
class  RegexPattern;
struct REStackFrame;
class  RuleBasedBreakIterator;
class  UnicodeSet;
class  UVector;
class  UVector32;
class  UVector64;


/**
  * Class <code>RegexPattern</code> represents a compiled regular expression.  It includes
  * factory methods for creating a RegexPattern object from the source (string) form
  * of a regular expression, methods for creating RegexMatchers that allow the pattern
  * to be applied to input text, and a few convenience methods for simple common
  * uses of regular expressions.
  *
  * <p>Class RegexPattern is not intended to be subclassed.</p>
  *
  * @stable ICU 2.4
  */
class U_I18N_API RegexPattern U_FINAL : public UObject {
public:

    /**
     * default constructor.  Create a RegexPattern object that refers to no actual
     *   pattern.  Not normally needed; RegexPattern objects are usually
     *   created using the factory method <code>compile()</code>.
     *
     * @stable ICU 2.4
     */
    RegexPattern();

    /**
     * Copy Constructor.  Create a new RegexPattern object that is equivalent
     *                    to the source object.
     * @param source the pattern object to be copied.
     * @stable ICU 2.4
     */
    RegexPattern(const RegexPattern &source);

    /**
     * Destructor.  Note that a RegexPattern object must persist so long as any
     *  RegexMatcher objects that were created from the RegexPattern are active.
     * @stable ICU 2.4
     */
    virtual ~RegexPattern();

    /**
     * Comparison operator.  Two RegexPattern objects are considered equal if they
     * were constructed from identical source patterns using the same match flag
     * settings.
     * @param that a RegexPattern object to compare with "this".
     * @return TRUE if the objects are equivalent.
     * @stable ICU 2.4
     */
    UBool           operator==(const RegexPattern& that) const;

    /**
     * Comparison operator.  Two RegexPattern objects are considered equal if they
     * were constructed from identical source patterns using the same match flag
     * settings.
     * @param that a RegexPattern object to compare with "this".
     * @return TRUE if the objects are different.
     * @stable ICU 2.4
     */
    inline UBool    operator!=(const RegexPattern& that) const {return ! operator ==(that);}

    /**
     * Assignment operator.  After assignment, this RegexPattern will behave identically
     *     to the source object.
     * @stable ICU 2.4
     */
    RegexPattern  &operator =(const RegexPattern &source);

    /**
     * Create an exact copy of this RegexPattern object.  Since RegexPattern is not
     * intended to be subclassed, <code>clone()</code> and the copy construction are
     * equivalent operations.
     * @return the copy of this RegexPattern
     * @stable ICU 2.4
     */
    virtual RegexPattern  *clone() const;


   /**
    * Compiles the regular expression in string form into a RegexPattern
    * object.  These compile methods, rather than the constructors, are the usual
    * way that RegexPattern objects are created.
    *
    * <p>Note that RegexPattern objects must not be deleted while RegexMatcher
    * objects created from the pattern are active.  RegexMatchers keep a pointer
    * back to their pattern, so premature deletion of the pattern is a
    * catastrophic error.</p>
    *
    * <p>All pattern match mode flags are set to their default values.</p>
    *
    * <p>Note that it is often more convenient to construct a RegexMatcher directly
    *    from a pattern string rather than separately compiling the pattern and
    *    then creating a RegexMatcher object from the pattern.</p>
    *
    * @param regex The regular expression to be compiled.
    * @param pe    Receives the position (line and column nubers) of any error
    *              within the regular expression.)
    * @param status A reference to a UErrorCode to receive any errors.
    * @return      A regexPattern object for the compiled pattern.
    *
    * @stable ICU 2.4
    */
    static RegexPattern * U_EXPORT2 compile( const UnicodeString &regex,
        UParseError          &pe,
        UErrorCode           &status);

   /**
    * Compiles the regular expression in string form into a RegexPattern
    * object.  These compile methods, rather than the constructors, are the usual
    * way that RegexPattern objects are created.
    *
    * <p>Note that RegexPattern objects must not be deleted while RegexMatcher
    * objects created from the pattern are active.  RegexMatchers keep a pointer
    * back to their pattern, so premature deletion of the pattern is a
    * catastrophic error.</p>
    *
    * <p>All pattern match mode flags are set to their default values.</p>
    *
    * <p>Note that it is often more convenient to construct a RegexMatcher directly
    *    from a pattern string rather than separately compiling the pattern and
    *    then creating a RegexMatcher object from the pattern.</p>
    *
    * @param regex The regular expression to be compiled. Note, the text referred
    *              to by this UText must not be deleted during the lifetime of the
    *              RegexPattern object or any RegexMatcher object created from it.
    * @param pe    Receives the position (line and column nubers) of any error
    *              within the regular expression.)
    * @param status A reference to a UErrorCode to receive any errors.
    * @return      A regexPattern object for the compiled pattern.
    *
    * @stable ICU 4.6
    */
    static RegexPattern * U_EXPORT2 compile( UText *regex,
        UParseError          &pe,
        UErrorCode           &status);

   /**
    * Compiles the regular expression in string form into a RegexPattern
    * object using the specified match mode flags.  These compile methods,
    * rather than the constructors, are the usual way that RegexPattern objects
    * are created.
    *
    * <p>Note that RegexPattern objects must not be deleted while RegexMatcher
    * objects created from the pattern are active.  RegexMatchers keep a pointer
    * back to their pattern, so premature deletion of the pattern is a
    * catastrophic error.</p>
    *
    * <p>Note that it is often more convenient to construct a RegexMatcher directly
    *    from a pattern string instead of than separately compiling the pattern and
    *    then creating a RegexMatcher object from the pattern.</p>
    *
    * @param regex The regular expression to be compiled.
    * @param flags The match mode flags to be used.
    * @param pe    Receives the position (line and column numbers) of any error
    *              within the regular expression.)
    * @param status   A reference to a UErrorCode to receive any errors.
    * @return      A regexPattern object for the compiled pattern.
    *
    * @stable ICU 2.4
    */
    static RegexPattern * U_EXPORT2 compile( const UnicodeString &regex,
        uint32_t             flags,
        UParseError          &pe,
        UErrorCode           &status);

   /**
    * Compiles the regular expression in string form into a RegexPattern
    * object using the specified match mode flags.  These compile methods,
    * rather than the constructors, are the usual way that RegexPattern objects
    * are created.
    *
    * <p>Note that RegexPattern objects must not be deleted while RegexMatcher
    * objects created from the pattern are active.  RegexMatchers keep a pointer
    * back to their pattern, so premature deletion of the pattern is a
    * catastrophic error.</p>
    *
    * <p>Note that it is often more convenient to construct a RegexMatcher directly
    *    from a pattern string instead of than separately compiling the pattern and
    *    then creating a RegexMatcher object from the pattern.</p>
    *
    * @param regex The regular expression to be compiled. Note, the text referred
    *              to by this UText must not be deleted during the lifetime of the
    *              RegexPattern object or any RegexMatcher object created from it.
    * @param flags The match mode flags to be used.
    * @param pe    Receives the position (line and column numbers) of any error
    *              within the regular expression.)
    * @param status   A reference to a UErrorCode to receive any errors.
    * @return      A regexPattern object for the compiled pattern.
    *
    * @stable ICU 4.6
    */
    static RegexPattern * U_EXPORT2 compile( UText *regex,
        uint32_t             flags,
        UParseError          &pe,
        UErrorCode           &status);

   /**
    * Compiles the regular expression in string form into a RegexPattern
    * object using the specified match mode flags.  These compile methods,
    * rather than the constructors, are the usual way that RegexPattern objects
    * are created.
    *
    * <p>Note that RegexPattern objects must not be deleted while RegexMatcher
    * objects created from the pattern are active.  RegexMatchers keep a pointer
    * back to their pattern, so premature deletion of the pattern is a
    * catastrophic error.</p>
    *
    * <p>Note that it is often more convenient to construct a RegexMatcher directly
    *    from a pattern string instead of than separately compiling the pattern and
    *    then creating a RegexMatcher object from the pattern.</p>
    *
    * @param regex The regular expression to be compiled.
    * @param flags The match mode flags to be used.
    * @param status   A reference to a UErrorCode to receive any errors.
    * @return      A regexPattern object for the compiled pattern.
    *
    * @stable ICU 2.6
    */
    static RegexPattern * U_EXPORT2 compile( const UnicodeString &regex,
        uint32_t             flags,
        UErrorCode           &status);

   /**
    * Compiles the regular expression in string form into a RegexPattern
    * object using the specified match mode flags.  These compile methods,
    * rather than the constructors, are the usual way that RegexPattern objects
    * are created.
    *
    * <p>Note that RegexPattern objects must not be deleted while RegexMatcher
    * objects created from the pattern are active.  RegexMatchers keep a pointer
    * back to their pattern, so premature deletion of the pattern is a
    * catastrophic error.</p>
    *
    * <p>Note that it is often more convenient to construct a RegexMatcher directly
    *    from a pattern string instead of than separately compiling the pattern and
    *    then creating a RegexMatcher object from the pattern.</p>
    *
    * @param regex The regular expression to be compiled. Note, the text referred
    *              to by this UText must not be deleted during the lifetime of the
    *              RegexPattern object or any RegexMatcher object created from it.
    * @param flags The match mode flags to be used.
    * @param status   A reference to a UErrorCode to receive any errors.
    * @return      A regexPattern object for the compiled pattern.
    *
    * @stable ICU 4.6
    */
    static RegexPattern * U_EXPORT2 compile( UText *regex,
        uint32_t             flags,
        UErrorCode           &status);

   /**
    * Get the match mode flags that were used when compiling this pattern.
    * @return  the match mode flags
    * @stable ICU 2.4
    */
    virtual uint32_t flags() const;

   /**
    * Creates a RegexMatcher that will match the given input against this pattern.  The
    * RegexMatcher can then be used to perform match, find or replace operations
    * on the input.  Note that a RegexPattern object must not be deleted while
    * RegexMatchers created from it still exist and might possibly be used again.
    * <p>
    * The matcher will retain a reference to the supplied input string, and all regexp
    * pattern matching operations happen directly on this original string.  It is
    * critical that the string not be altered or deleted before use by the regular
    * expression operations is complete.
    *
    * @param input    The input string to which the regular expression will be applied.
    * @param status   A reference to a UErrorCode to receive any errors.
    * @return         A RegexMatcher object for this pattern and input.
    *
    * @stable ICU 2.4
    */
    virtual RegexMatcher *matcher(const UnicodeString &input,
        UErrorCode          &status) const;
        
private:
    /**
     * Cause a compilation error if an application accidentally attempts to
     *   create a matcher with a (UChar *) string as input rather than
     *   a UnicodeString.  Avoids a dangling reference to a temporary string.
     * <p>
     * To efficiently work with UChar *strings, wrap the data in a UnicodeString
     * using one of the aliasing constructors, such as
     * <code>UnicodeString(UBool isTerminated, const UChar *text, int32_t textLength);</code>
     * or in a UText, using
     * <code>utext_openUChars(UText *ut, const UChar *text, int64_t textLength, UErrorCode *status);</code>
     *
     */
    RegexMatcher *matcher(const UChar *input,
        UErrorCode          &status) const;
public:


   /**
    * Creates a RegexMatcher that will match against this pattern.  The
    * RegexMatcher can be used to perform match, find or replace operations.
    * Note that a RegexPattern object must not be deleted while
    * RegexMatchers created from it still exist and might possibly be used again.
    *
    * @param status   A reference to a UErrorCode to receive any errors.
    * @return      A RegexMatcher object for this pattern and input.
    *
    * @stable ICU 2.6
    */
    virtual RegexMatcher *matcher(UErrorCode  &status) const;


   /**
    * Test whether a string matches a regular expression.  This convenience function
    * both compiles the regular expression and applies it in a single operation.
    * Note that if the same pattern needs to be applied repeatedly, this method will be
    * less efficient than creating and reusing a RegexMatcher object.
    *
    * @param regex The regular expression
    * @param input The string data to be matched
    * @param pe Receives the position of any syntax errors within the regular expression
    * @param status A reference to a UErrorCode to receive any errors.
    * @return True if the regular expression exactly matches the full input string.
    *
    * @stable ICU 2.4
    */
    static UBool U_EXPORT2 matches(const UnicodeString   &regex,
        const UnicodeString   &input,
              UParseError     &pe,
              UErrorCode      &status);

   /**
    * Test whether a string matches a regular expression.  This convenience function
    * both compiles the regular expression and applies it in a single operation.
    * Note that if the same pattern needs to be applied repeatedly, this method will be
    * less efficient than creating and reusing a RegexMatcher object.
    *
    * @param regex The regular expression
    * @param input The string data to be matched
    * @param pe Receives the position of any syntax errors within the regular expression
    * @param status A reference to a UErrorCode to receive any errors.
    * @return True if the regular expression exactly matches the full input string.
    *
    * @stable ICU 4.6
    */
    static UBool U_EXPORT2 matches(UText *regex,
        UText           *input,
        UParseError     &pe,
        UErrorCode      &status);

   /**
    * Returns the regular expression from which this pattern was compiled. This method will work
    * even if the pattern was compiled from a UText.
    *
    * Note: If the pattern was originally compiled from a UText, and that UText was modified,
    * the returned string may no longer reflect the RegexPattern object.
    * @stable ICU 2.4
    */
    virtual UnicodeString pattern() const;
    
    
   /**
    * Returns the regular expression from which this pattern was compiled. This method will work
    * even if the pattern was compiled from a UnicodeString.
    *
    * Note: This is the original input, not a clone. If the pattern was originally compiled from a
    * UText, and that UText was modified, the returned UText may no longer reflect the RegexPattern
    * object.
    *
    * @stable ICU 4.6
    */
    virtual UText *patternText(UErrorCode      &status) const;


    /**
     * Get the group number corresponding to a named capture group.
     * The returned number can be used with any function that access
     * capture groups by number.
     *
     * The function returns an error status if the specified name does not
     * appear in the pattern.
     *
     * @param  groupName   The capture group name.
     * @param  status      A UErrorCode to receive any errors.
     *
     * @stable ICU 55
     */
    virtual int32_t groupNumberFromName(const UnicodeString &groupName, UErrorCode &status) const;


    /**
     * Get the group number corresponding to a named capture group.
     * The returned number can be used with any function that access
     * capture groups by number.
     *
     * The function returns an error status if the specified name does not
     * appear in the pattern.
     *
     * @param  groupName   The capture group name,
     *                     platform invariant characters only.
     * @param  nameLength  The length of the name, or -1 if the name is
     *                     nul-terminated.
     * @param  status      A UErrorCode to receive any errors.
     *
     * @stable ICU 55
     */
    virtual int32_t groupNumberFromName(const char *groupName, int32_t nameLength, UErrorCode &status) const;


    /**
     * Split a string into fields.  Somewhat like split() from Perl or Java.
     * Pattern matches identify delimiters that separate the input
     * into fields.  The input data between the delimiters becomes the
     * fields themselves.
     *
     * If the delimiter pattern includes capture groups, the captured text will
     * also appear in the destination array of output strings, interspersed
     * with the fields.  This is similar to Perl, but differs from Java, 
     * which ignores the presence of capture groups in the pattern.
     * 
     * Trailing empty fields will always be returned, assuming sufficient
     * destination capacity.  This differs from the default behavior for Java
     * and Perl where trailing empty fields are not returned.
     *
     * The number of strings produced by the split operation is returned.
     * This count includes the strings from capture groups in the delimiter pattern.
     * This behavior differs from Java, which ignores capture groups.
     *
     * For the best performance on split() operations,
     * <code>RegexMatcher::split</code> is preferable to this function
     *
     * @param input   The string to be split into fields.  The field delimiters
     *                match the pattern (in the "this" object)
     * @param dest    An array of UnicodeStrings to receive the results of the split.
     *                This is an array of actual UnicodeString objects, not an
     *                array of pointers to strings.  Local (stack based) arrays can
     *                work well here.
     * @param destCapacity  The number of elements in the destination array.
     *                If the number of fields found is less than destCapacity, the
     *                extra strings in the destination array are not altered.
     *                If the number of destination strings is less than the number
     *                of fields, the trailing part of the input string, including any
     *                field delimiters, is placed in the last destination string.
     * @param status  A reference to a UErrorCode to receive any errors.
     * @return        The number of fields into which the input string was split.
     * @stable ICU 2.4
     */
    virtual int32_t  split(const UnicodeString &input,
        UnicodeString    dest[],
        int32_t          destCapacity,
        UErrorCode       &status) const;


    /**
     * Split a string into fields.  Somewhat like split() from Perl or Java.
     * Pattern matches identify delimiters that separate the input
     * into fields.  The input data between the delimiters becomes the
     * fields themselves.
     *
     * If the delimiter pattern includes capture groups, the captured text will
     * also appear in the destination array of output strings, interspersed
     * with the fields.  This is similar to Perl, but differs from Java, 
     * which ignores the presence of capture groups in the pattern.
     * 
     * Trailing empty fields will always be returned, assuming sufficient
     * destination capacity.  This differs from the default behavior for Java
     * and Perl where trailing empty fields are not returned.
     *
     * The number of strings produced by the split operation is returned.
     * This count includes the strings from capture groups in the delimiter pattern.
     * This behavior differs from Java, which ignores capture groups.
     *
     *  For the best performance on split() operations,
     *  <code>RegexMatcher::split</code> is preferable to this function
     *
     * @param input   The string to be split into fields.  The field delimiters
     *                match the pattern (in the "this" object)
     * @param dest    An array of mutable UText structs to receive the results of the split.
     *                If a field is NULL, a new UText is allocated to contain the results for
     *                that field. This new UText is not guaranteed to be mutable.
     * @param destCapacity  The number of elements in the destination array.
     *                If the number of fields found is less than destCapacity, the
     *                extra strings in the destination array are not altered.
     *                If the number of destination strings is less than the number
     *                of fields, the trailing part of the input string, including any
     *                field delimiters, is placed in the last destination string.
     * @param status  A reference to a UErrorCode to receive any errors.
     * @return        The number of destination strings used.  
     *
     * @stable ICU 4.6
     */
    virtual int32_t  split(UText *input,
        UText            *dest[],
        int32_t          destCapacity,
        UErrorCode       &status) const;


    /**
     * ICU "poor man's RTTI", returns a UClassID for the actual class.
     *
     * @stable ICU 2.4
     */
    virtual UClassID getDynamicClassID() const;

    /**
     * ICU "poor man's RTTI", returns a UClassID for this class.
     *
     * @stable ICU 2.4
     */
    static UClassID U_EXPORT2 getStaticClassID();

private:
    //
    //  Implementation Data
    //
    UText          *fPattern;      // The original pattern string.
    UnicodeString  *fPatternString; // The original pattern UncodeString if relevant
    uint32_t        fFlags;        // The flags used when compiling the pattern.
                                   //
    UVector64       *fCompiledPat; // The compiled pattern p-code.
    UnicodeString   fLiteralText;  // Any literal string data from the pattern,
                                   //   after un-escaping, for use during the match.

    UVector         *fSets;        // Any UnicodeSets referenced from the pattern.
    Regex8BitSet    *fSets8;       //      (and fast sets for latin-1 range.)


    UErrorCode      fDeferredStatus; // status if some prior error has left this
                                   //  RegexPattern in an unusable state.

    int32_t         fMinMatchLen;  // Minimum Match Length.  All matches will have length
                                   //   >= this value.  For some patterns, this calculated
                                   //   value may be less than the true shortest
                                   //   possible match.
    
    int32_t         fFrameSize;    // Size of a state stack frame in the
                                   //   execution engine.

    int32_t         fDataSize;     // The size of the data needed by the pattern that
                                   //   does not go on the state stack, but has just
                                   //   a single copy per matcher.

    UVector32       *fGroupMap;    // Map from capture group number to position of
                                   //   the group's variables in the matcher stack frame.

    UnicodeSet     **fStaticSets;  // Ptr to static (shared) sets for predefined
                                   //   regex character classes, e.g. Word.

    Regex8BitSet   *fStaticSets8;  // Ptr to the static (shared) latin-1 only
                                   //  sets for predefined regex classes.

    int32_t         fStartType;    // Info on how a match must start.
    int32_t         fInitialStringIdx;     //
    int32_t         fInitialStringLen;
    UnicodeSet     *fInitialChars;
    UChar32         fInitialChar;
    Regex8BitSet   *fInitialChars8;
    UBool           fNeedsAltInput;

    UHashtable     *fNamedCaptureMap;  // Map from capture group names to numbers.

    friend class RegexCompile;
    friend class RegexMatcher;
    friend class RegexCImpl;

    //
    //  Implementation Methods
    //
    void        init();            // Common initialization, for use by constructors.
    void        zap();             // Common cleanup

    void        dumpOp(int32_t index) const;

  public:
#ifndef U_HIDE_INTERNAL_API
    /**
      * Dump a compiled pattern. Internal debug function.
      * @internal
      */
    void        dumpPattern() const;
#endif  /* U_HIDE_INTERNAL_API */
};



/**
 *  class RegexMatcher bundles together a regular expression pattern and
 *  input text to which the expression can be applied.  It includes methods
 *  for testing for matches, and for find and replace operations.
 *
 * <p>Class RegexMatcher is not intended to be subclassed.</p>
 *
 * @stable ICU 2.4
 */
class U_I18N_API RegexMatcher U_FINAL : public UObject {
public:

    /**
      * Construct a RegexMatcher for a regular expression.
      * This is a convenience method that avoids the need to explicitly create
      * a RegexPattern object.  Note that if several RegexMatchers need to be
      * created for the same expression, it will be more efficient to
      * separately create and cache a RegexPattern object, and use
      * its matcher() method to create the RegexMatcher objects.
      *
      *  @param regexp The Regular Expression to be compiled.
      *  @param flags  Regular expression options, such as case insensitive matching.
      *                @see UREGEX_CASE_INSENSITIVE
      *  @param status Any errors are reported by setting this UErrorCode variable.
      *  @stable ICU 2.6
      */
    RegexMatcher(const UnicodeString &regexp, uint32_t flags, UErrorCode &status);

    /**
      * Construct a RegexMatcher for a regular expression.
      * This is a convenience method that avoids the need to explicitly create
      * a RegexPattern object.  Note that if several RegexMatchers need to be
      * created for the same expression, it will be more efficient to
      * separately create and cache a RegexPattern object, and use
      * its matcher() method to create the RegexMatcher objects.
      *
      *  @param regexp The regular expression to be compiled.
      *  @param flags  Regular expression options, such as case insensitive matching.
      *                @see UREGEX_CASE_INSENSITIVE
      *  @param status Any errors are reported by setting this UErrorCode variable.
      *
      *  @stable ICU 4.6
      */
    RegexMatcher(UText *regexp, uint32_t flags, UErrorCode &status);

    /**
      * Construct a RegexMatcher for a regular expression.
      * This is a convenience method that avoids the need to explicitly create
      * a RegexPattern object.  Note that if several RegexMatchers need to be
      * created for the same expression, it will be more efficient to
      * separately create and cache a RegexPattern object, and use
      * its matcher() method to create the RegexMatcher objects.
      * <p>
      * The matcher will retain a reference to the supplied input string, and all regexp
      * pattern matching operations happen directly on the original string.  It is
      * critical that the string not be altered or deleted before use by the regular
      * expression operations is complete.
      *
      *  @param regexp The Regular Expression to be compiled.
      *  @param input  The string to match.  The matcher retains a reference to the
      *                caller's string; mo copy is made.
      *  @param flags  Regular expression options, such as case insensitive matching.
      *                @see UREGEX_CASE_INSENSITIVE
      *  @param status Any errors are reported by setting this UErrorCode variable.
      *  @stable ICU 2.6
      */
    RegexMatcher(const UnicodeString &regexp, const UnicodeString &input,
        uint32_t flags, UErrorCode &status);

    /**
      * Construct a RegexMatcher for a regular expression.
      * This is a convenience method that avoids the need to explicitly create
      * a RegexPattern object.  Note that if several RegexMatchers need to be
      * created for the same expression, it will be more efficient to
      * separately create and cache a RegexPattern object, and use
      * its matcher() method to create the RegexMatcher objects.
      * <p>
      * The matcher will make a shallow clone of the supplied input text, and all regexp
      * pattern matching operations happen on this clone.  While read-only operations on
      * the supplied text are permitted, it is critical that the underlying string not be
      * altered or deleted before use by the regular expression operations is complete.
      *
      *  @param regexp The Regular Expression to be compiled.
      *  @param input  The string to match.  The matcher retains a shallow clone of the text.
      *  @param flags  Regular expression options, such as case insensitive matching.
      *                @see UREGEX_CASE_INSENSITIVE
      *  @param status Any errors are reported by setting this UErrorCode variable.
      *
      *  @stable ICU 4.6
      */
    RegexMatcher(UText *regexp, UText *input,
        uint32_t flags, UErrorCode &status);

private:
    /**
     * Cause a compilation error if an application accidentally attempts to
     *   create a matcher with a (UChar *) string as input rather than
     *   a UnicodeString.    Avoids a dangling reference to a temporary string.
     * <p>
     * To efficiently work with UChar *strings, wrap the data in a UnicodeString
     * using one of the aliasing constructors, such as
     * <code>UnicodeString(UBool isTerminated, const UChar *text, int32_t textLength);</code>
     * or in a UText, using
     * <code>utext_openUChars(UText *ut, const UChar *text, int64_t textLength, UErrorCode *status);</code>
     *
     */
    RegexMatcher(const UnicodeString &regexp, const UChar *input,
        uint32_t flags, UErrorCode &status);
public:


   /**
    *   Destructor.
    *
    *  @stable ICU 2.4
    */
    virtual ~RegexMatcher();


   /**
    *   Attempts to match the entire input region against the pattern.
    *    @param   status     A reference to a UErrorCode to receive any errors.
    *    @return TRUE if there is a match
    *    @stable ICU 2.4
    */
    virtual UBool matches(UErrorCode &status);


   /**
    *   Resets the matcher, then attempts to match the input beginning 
    *   at the specified startIndex, and extending to the end of the input.
    *   The input region is reset to include the entire input string.
    *   A successful match must extend to the end of the input.
    *    @param   startIndex The input string (native) index at which to begin matching.
    *    @param   status     A reference to a UErrorCode to receive any errors.
    *    @return TRUE if there is a match
    *    @stable ICU 2.8
    */
    virtual UBool matches(int64_t startIndex, UErrorCode &status);


   /**
    *   Attempts to match the input string, starting from the beginning of the region,
    *   against the pattern.  Like the matches() method, this function 
    *   always starts at the beginning of the input region;
    *   unlike that function, it does not require that the entire region be matched.
    *
    *   <p>If the match succeeds then more information can be obtained via the <code>start()</code>,
    *     <code>end()</code>, and <code>group()</code> functions.</p>
    *
    *    @param   status     A reference to a UErrorCode to receive any errors.
    *    @return  TRUE if there is a match at the start of the input string.
    *    @stable ICU 2.4
    */
    virtual UBool lookingAt(UErrorCode &status);


  /**
    *   Attempts to match the input string, starting from the specified index, against the pattern.
    *   The match may be of any length, and is not required to extend to the end
    *   of the input string.  Contrast with match().
    *
    *   <p>If the match succeeds then more information can be obtained via the <code>start()</code>,
    *     <code>end()</code>, and <code>group()</code> functions.</p>
    *
    *    @param   startIndex The input string (native) index at which to begin matching.
    *    @param   status     A reference to a UErrorCode to receive any errors.
    *    @return  TRUE if there is a match.
    *    @stable ICU 2.8
    */
    virtual UBool lookingAt(int64_t startIndex, UErrorCode &status);


   /**
    *  Find the next pattern match in the input string.
    *  The find begins searching the input at the location following the end of
    *  the previous match, or at the start of the string if there is no previous match.
    *  If a match is found, <code>start(), end()</code> and <code>group()</code>
    *  will provide more information regarding the match.
    *  <p>Note that if the input string is changed by the application,
    *     use find(startPos, status) instead of find(), because the saved starting
    *     position may not be valid with the altered input string.</p>
    *  @return  TRUE if a match is found.
    *  @stable ICU 2.4
    */
    virtual UBool find();


   /**
    *  Find the next pattern match in the input string.
    *  The find begins searching the input at the location following the end of
    *  the previous match, or at the start of the string if there is no previous match.
    *  If a match is found, <code>start(), end()</code> and <code>group()</code>
    *  will provide more information regarding the match.
    *  <p>Note that if the input string is changed by the application,
    *     use find(startPos, status) instead of find(), because the saved starting
    *     position may not be valid with the altered input string.</p>
    *  @param   status  A reference to a UErrorCode to receive any errors.
    *  @return  TRUE if a match is found.
    * @stable ICU 55
    */
    virtual UBool find(UErrorCode &status);

   /**
    *   Resets this RegexMatcher and then attempts to find the next substring of the
    *   input string that matches the pattern, starting at the specified index.
    *
    *   @param   start     The (native) index in the input string to begin the search.
    *   @param   status    A reference to a UErrorCode to receive any errors.
    *   @return  TRUE if a match is found.
    *   @stable ICU 2.4
    */
    virtual UBool find(int64_t start, UErrorCode &status);


   /**
    *   Returns a string containing the text matched by the previous match.
    *   If the pattern can match an empty string, an empty string may be returned.
    *   @param   status      A reference to a UErrorCode to receive any errors.
    *                        Possible errors are  U_REGEX_INVALID_STATE if no match
    *                        has been attempted or the last match failed.
    *   @return  a string containing the matched input text.
    *   @stable ICU 2.4
    */
    virtual UnicodeString group(UErrorCode &status) const;


   /**
    *    Returns a string containing the text captured by the given group
    *    during the previous match operation.  Group(0) is the entire match.
    *
    *    A zero length string is returned both for capture groups that did not
    *    participate in the match and for actual zero length matches.
    *    To distinguish between these two cases use the function start(),
    *    which returns -1 for non-participating groups.
    *
    *    @param groupNum the capture group number
    *    @param   status     A reference to a UErrorCode to receive any errors.
    *                        Possible errors are  U_REGEX_INVALID_STATE if no match
    *                        has been attempted or the last match failed and
    *                        U_INDEX_OUTOFBOUNDS_ERROR for a bad capture group number.
    *    @return the captured text
    *    @stable ICU 2.4
    */
    virtual UnicodeString group(int32_t groupNum, UErrorCode &status) const;

   /**
    *   Returns the number of capturing groups in this matcher's pattern.
    *   @return the number of capture groups
    *   @stable ICU 2.4
    */
    virtual int32_t groupCount() const;


   /**
    *   Returns a shallow clone of the entire live input string with the UText current native index
    *   set to the beginning of the requested group.
    *
    *   @param   dest        The UText into which the input should be cloned, or NULL to create a new UText
    *   @param   group_len   A reference to receive the length of the desired capture group
    *   @param   status      A reference to a UErrorCode to receive any errors.
    *                        Possible errors are  U_REGEX_INVALID_STATE if no match
    *                        has been attempted or the last match failed and
    *                        U_INDEX_OUTOFBOUNDS_ERROR for a bad capture group number.
    *   @return dest if non-NULL, a shallow copy of the input text otherwise
    *
    *   @stable ICU 4.6
    */
    virtual UText *group(UText *dest, int64_t &group_len, UErrorCode &status) const; 

   /**
    *   Returns a shallow clone of the entire live input string with the UText current native index
    *   set to the beginning of the requested group.
    *
    *   A group length of zero is returned both for capture groups that did not
    *   participate in the match and for actual zero length matches.
    *   To distinguish between these two cases use the function start(),
    *   which returns -1 for non-participating groups.
    *
    *   @param   groupNum   The capture group number.
    *   @param   dest        The UText into which the input should be cloned, or NULL to create a new UText.
    *   @param   group_len   A reference to receive the length of the desired capture group
    *   @param   status      A reference to a UErrorCode to receive any errors.
    *                        Possible errors are  U_REGEX_INVALID_STATE if no match
    *                        has been attempted or the last match failed and
    *                        U_INDEX_OUTOFBOUNDS_ERROR for a bad capture group number.
    *   @return dest if non-NULL, a shallow copy of the input text otherwise
    *
    *   @stable ICU 4.6
    */
    virtual UText *group(int32_t groupNum, UText *dest, int64_t &group_len, UErrorCode &status) const;

   /**
    *   Returns the index in the input string of the start of the text matched
    *   during the previous match operation.
    *    @param   status      a reference to a UErrorCode to receive any errors.
    *    @return              The (native) position in the input string of the start of the last match.
    *    @stable ICU 2.4
    */
    virtual int32_t start(UErrorCode &status) const;

   /**
    *   Returns the index in the input string of the start of the text matched
    *   during the previous match operation.
    *    @param   status      a reference to a UErrorCode to receive any errors.
    *    @return              The (native) position in the input string of the start of the last match.
    *   @stable ICU 4.6
    */
    virtual int64_t start64(UErrorCode &status) const;


   /**
    *   Returns the index in the input string of the start of the text matched by the
    *    specified capture group during the previous match operation.  Return -1 if
    *    the capture group exists in the pattern, but was not part of the last match.
    *
    *    @param  group       the capture group number
    *    @param  status      A reference to a UErrorCode to receive any errors.  Possible
    *                        errors are  U_REGEX_INVALID_STATE if no match has been
    *                        attempted or the last match failed, and
    *                        U_INDEX_OUTOFBOUNDS_ERROR for a bad capture group number
    *    @return the (native) start position of substring matched by the specified group.
    *    @stable ICU 2.4
    */
    virtual int32_t start(int32_t group, UErrorCode &status) const;

   /**
    *   Returns the index in the input string of the start of the text matched by the
    *    specified capture group during the previous match operation.  Return -1 if
    *    the capture group exists in the pattern, but was not part of the last match.
    *
    *    @param  group       the capture group number.
    *    @param  status      A reference to a UErrorCode to receive any errors.  Possible
    *                        errors are  U_REGEX_INVALID_STATE if no match has been
    *                        attempted or the last match failed, and
    *                        U_INDEX_OUTOFBOUNDS_ERROR for a bad capture group number.
    *    @return the (native) start position of substring matched by the specified group.
    *    @stable ICU 4.6
    */
    virtual int64_t start64(int32_t group, UErrorCode &status) const;

   /**
    *    Returns the index in the input string of the first character following the
    *    text matched during the previous match operation.
    *
    *   @param   status      A reference to a UErrorCode to receive any errors.  Possible
    *                        errors are  U_REGEX_INVALID_STATE if no match has been
    *                        attempted or the last match failed.
    *    @return the index of the last character matched, plus one.
    *                        The index value returned is a native index, corresponding to
    *                        code units for the underlying encoding type, for example,
    *                        a byte index for UTF-8.
    *   @stable ICU 2.4
    */
    virtual int32_t end(UErrorCode &status) const;

   /**
    *    Returns the index in the input string of the first character following the
    *    text matched during the previous match operation.
    *
    *   @param   status      A reference to a UErrorCode to receive any errors.  Possible
    *                        errors are  U_REGEX_INVALID_STATE if no match has been
    *                        attempted or the last match failed.
    *    @return the index of the last character matched, plus one.
    *                        The index value returned is a native index, corresponding to
    *                        code units for the underlying encoding type, for example,
    *                        a byte index for UTF-8.
    *   @stable ICU 4.6
    */
    virtual int64_t end64(UErrorCode &status) const;


   /**
    *    Returns the index in the input string of the character following the
    *    text matched by the specified capture group during the previous match operation.
    *
    *    @param group  the capture group number
    *    @param   status      A reference to a UErrorCode to receive any errors.  Possible
    *                        errors are  U_REGEX_INVALID_STATE if no match has been
    *                        attempted or the last match failed and
    *                        U_INDEX_OUTOFBOUNDS_ERROR for a bad capture group number
    *    @return  the index of the first character following the text
    *              captured by the specified group during the previous match operation.
    *              Return -1 if the capture group exists in the pattern but was not part of the match.
    *              The index value returned is a native index, corresponding to
    *              code units for the underlying encoding type, for example,
    *              a byte index for UTF8.
    *    @stable ICU 2.4
    */
    virtual int32_t end(int32_t group, UErrorCode &status) const;

   /**
    *    Returns the index in the input string of the character following the
    *    text matched by the specified capture group during the previous match operation.
    *
    *    @param group  the capture group number
    *    @param   status      A reference to a UErrorCode to receive any errors.  Possible
    *                        errors are  U_REGEX_INVALID_STATE if no match has been
    *                        attempted or the last match failed and
    *                        U_INDEX_OUTOFBOUNDS_ERROR for a bad capture group number
    *    @return  the index of the first character following the text
    *              captured by the specified group during the previous match operation.
    *              Return -1 if the capture group exists in the pattern but was not part of the match.
    *              The index value returned is a native index, corresponding to
    *              code units for the underlying encoding type, for example,
    *              a byte index for UTF8.
    *   @stable ICU 4.6
    */
    virtual int64_t end64(int32_t group, UErrorCode &status) const;

   /**
    *   Resets this matcher.  The effect is to remove any memory of previous matches,
    *       and to cause subsequent find() operations to begin at the beginning of
    *       the input string.
    *
    *   @return this RegexMatcher.
    *   @stable ICU 2.4
    */
    virtual RegexMatcher &reset();


   /**
    *   Resets this matcher, and set the current input position.
    *   The effect is to remove any memory of previous matches,
    *       and to cause subsequent find() operations to begin at
    *       the specified (native) position in the input string.
    * <p>
    *   The matcher's region is reset to its default, which is the entire
    *   input string.
    * <p>
    *   An alternative to this function is to set a match region
    *   beginning at the desired index.
    *
    *   @return this RegexMatcher.
    *   @stable ICU 2.8
    */
    virtual RegexMatcher &reset(int64_t index, UErrorCode &status);


   /**
    *   Resets this matcher with a new input string.  This allows instances of RegexMatcher
    *     to be reused, which is more efficient than creating a new RegexMatcher for
    *     each input string to be processed.
    *   @param input The new string on which subsequent pattern matches will operate.
    *                The matcher retains a reference to the callers string, and operates
    *                directly on that.  Ownership of the string remains with the caller.
    *                Because no copy of the string is made, it is essential that the
    *                caller not delete the string until after regexp operations on it
    *                are done.
    *                Note that while a reset on the matcher with an input string that is then
    *                modified across/during matcher operations may be supported currently for UnicodeString,
    *                this was not originally intended behavior, and support for this is not guaranteed
    *                in upcoming versions of ICU.
    *   @return this RegexMatcher.
    *   @stable ICU 2.4
    */
    virtual RegexMatcher &reset(const UnicodeString &input);


   /**
    *   Resets this matcher with a new input string.  This allows instances of RegexMatcher
    *     to be reused, which is more efficient than creating a new RegexMatcher for
    *     each input string to be processed.
    *   @param input The new string on which subsequent pattern matches will operate.
    *                The matcher makes a shallow clone of the given text; ownership of the
    *                original string remains with the caller. Because no deep copy of the
    *                text is made, it is essential that the caller not modify the string
    *                until after regexp operations on it are done.
    *   @return this RegexMatcher.
    *
    *   @stable ICU 4.6
    */
    virtual RegexMatcher &reset(UText *input);


  /**
    *  Set the subject text string upon which the regular expression is looking for matches
    *  without changing any other aspect of the matching state.
    *  The new and previous text strings must have the same content.
    *
    *  This function is intended for use in environments where ICU is operating on 
    *  strings that may move around in memory.  It provides a mechanism for notifying
    *  ICU that the string has been relocated, and providing a new UText to access the
    *  string in its new position.
    *
    *  Note that the regular expression implementation never copies the underlying text
    *  of a string being matched, but always operates directly on the original text 
    *  provided by the user. Refreshing simply drops the references to the old text 
    *  and replaces them with references to the new.
    *
    *  Caution:  this function is normally used only by very specialized,
    *  system-level code.  One example use case is with garbage collection that moves
    *  the text in memory.
    *
    * @param input      The new (moved) text string.
    * @param status     Receives errors detected by this function.
    *
    * @stable ICU 4.8 
    */
    virtual RegexMatcher &refreshInputText(UText *input, UErrorCode &status);

private:
    /**
     * Cause a compilation error if an application accidentally attempts to
     *   reset a matcher with a (UChar *) string as input rather than
     *   a UnicodeString.    Avoids a dangling reference to a temporary string.
     * <p>
     * To efficiently work with UChar *strings, wrap the data in a UnicodeString
     * using one of the aliasing constructors, such as
     * <code>UnicodeString(UBool isTerminated, const UChar *text, int32_t textLength);</code>
     * or in a UText, using
     * <code>utext_openUChars(UText *ut, const UChar *text, int64_t textLength, UErrorCode *status);</code>
     *
     */
    RegexMatcher &reset(const UChar *input);
public:

   /**
    *   Returns the input string being matched.  Ownership of the string belongs to
    *   the matcher; it should not be altered or deleted. This method will work even if the input
    *   was originally supplied as a UText.
    *   @return the input string
    *   @stable ICU 2.4
    */
    virtual const UnicodeString &input() const;
    
   /**
    *   Returns the input string being matched.  This is the live input text; it should not be
    *   altered or deleted. This method will work even if the input was originally supplied as
    *   a UnicodeString.
    *   @return the input text
    *
    *   @stable ICU 4.6
    */
    virtual UText *inputText() const;
    
   /**
    *   Returns the input string being matched, either by copying it into the provided
    *   UText parameter or by returning a shallow clone of the live input. Note that copying
    *   the entire input may cause significant performance and memory issues.
    *   @param dest The UText into which the input should be copied, or NULL to create a new UText
    *   @param status error code
    *   @return dest if non-NULL, a shallow copy of the input text otherwise
    *
    *   @stable ICU 4.6
    */
    virtual UText *getInput(UText *dest, UErrorCode &status) const;
    

   /** Sets the limits of this matcher's region.
     * The region is the part of the input string that will be searched to find a match.
     * Invoking this method resets the matcher, and then sets the region to start
     * at the index specified by the start parameter and end at the index specified
     * by the end parameter.
     *
     * Depending on the transparency and anchoring being used (see useTransparentBounds
     * and useAnchoringBounds), certain constructs such as anchors may behave differently
     * at or around the boundaries of the region
     *
     * The function will fail if start is greater than limit, or if either index
     *  is less than zero or greater than the length of the string being matched.
     *
     * @param start  The (native) index to begin searches at.
     * @param limit  The index to end searches at (exclusive).
     * @param status A reference to a UErrorCode to receive any errors.
     * @stable ICU 4.0
     */
     virtual RegexMatcher &region(int64_t start, int64_t limit, UErrorCode &status);

   /** 
     * Identical to region(start, limit, status) but also allows a start position without
     *  resetting the region state.
     * @param regionStart The region start
     * @param regionLimit the limit of the region
     * @param startIndex  The (native) index within the region bounds at which to begin searches.
     * @param status A reference to a UErrorCode to receive any errors.
     *                If startIndex is not within the specified region bounds, 
     *                U_INDEX_OUTOFBOUNDS_ERROR is returned.
     * @stable ICU 4.6
     */
     virtual RegexMatcher &region(int64_t regionStart, int64_t regionLimit, int64_t startIndex, UErrorCode &status);

   /**
     * Reports the start index of this matcher's region. The searches this matcher
     * conducts are limited to finding matches within regionStart (inclusive) and
     * regionEnd (exclusive).
     *
     * @return The starting (native) index of this matcher's region.
     * @stable ICU 4.0
     */
     virtual int32_t regionStart() const;

   /**
     * Reports the start index of this matcher's region. The searches this matcher
     * conducts are limited to finding matches within regionStart (inclusive) and
     * regionEnd (exclusive).
     *
     * @return The starting (native) index of this matcher's region.
     * @stable ICU 4.6
     */
     virtual int64_t regionStart64() const;


    /**
      * Reports the end (limit) index (exclusive) of this matcher's region. The searches
      * this matcher conducts are limited to finding matches within regionStart
      * (inclusive) and regionEnd (exclusive).
      *
      * @return The ending point (native) of this matcher's region.
      * @stable ICU 4.0
      */
      virtual int32_t regionEnd() const;

   /**
     * Reports the end (limit) index (exclusive) of this matcher's region. The searches
     * this matcher conducts are limited to finding matches within regionStart
     * (inclusive) and regionEnd (exclusive).
     *
     * @return The ending point (native) of this matcher's region.
     * @stable ICU 4.6
     */
      virtual int64_t regionEnd64() const;

    /**
      * Queries the transparency of region bounds for this matcher.
      * See useTransparentBounds for a description of transparent and opaque bounds.
      * By default, a matcher uses opaque region boundaries.
      *
      * @return TRUE if this matcher is using opaque bounds, false if it is not.
      * @stable ICU 4.0
      */
      virtual UBool hasTransparentBounds() const;

    /**
      * Sets the transparency of region bounds for this matcher.
      * Invoking this function with an argument of true will set this matcher to use transparent bounds.
      * If the boolean argument is false, then opaque bounds will be used.
      *
      * Using transparent bounds, the boundaries of this matcher's region are transparent
      * to lookahead, lookbehind, and boundary matching constructs. Those constructs can
      * see text beyond the boundaries of the region while checking for a match.
      *
      * With opaque bounds, no text outside of the matcher's region is visible to lookahead,
      * lookbehind, and boundary matching constructs.
      *
      * By default, a matcher uses opaque bounds.
      *
      * @param   b TRUE for transparent bounds; FALSE for opaque bounds
      * @return  This Matcher;
      * @stable ICU 4.0
      **/
      virtual RegexMatcher &useTransparentBounds(UBool b);

     
    /**
      * Return true if this matcher is using anchoring bounds.
      * By default, matchers use anchoring region bounds.
      *
      * @return TRUE if this matcher is using anchoring bounds.
      * @stable ICU 4.0
      */    
      virtual UBool hasAnchoringBounds() const;


    /**
      * Set whether this matcher is using Anchoring Bounds for its region.
      * With anchoring bounds, pattern anchors such as ^ and $ will match at the start
      * and end of the region.  Without Anchoring Bounds, anchors will only match at
      * the positions they would in the complete text.
      *
      * Anchoring Bounds are the default for regions.
      *
      * @param b TRUE if to enable anchoring bounds; FALSE to disable them.
      * @return  This Matcher
      * @stable ICU 4.0
      */
      virtual RegexMatcher &useAnchoringBounds(UBool b);


    /**
      * Return TRUE if the most recent matching operation attempted to access
      *  additional input beyond the available input text.
      *  In this case, additional input text could change the results of the match.
      *
      *  hitEnd() is defined for both successful and unsuccessful matches.
      *  In either case hitEnd() will return TRUE if if the end of the text was
      *  reached at any point during the matching process.
      *
      *  @return  TRUE if the most recent match hit the end of input
      *  @stable ICU 4.0
      */
      virtual UBool hitEnd() const;

    /**
      * Return TRUE the most recent match succeeded and additional input could cause
      * it to fail. If this method returns false and a match was found, then more input
      * might change the match but the match won't be lost. If a match was not found,
      * then requireEnd has no meaning.
      *
      * @return TRUE if more input could cause the most recent match to no longer match.
      * @stable ICU 4.0
      */
      virtual UBool requireEnd() const;


   /**
    *    Returns the pattern that is interpreted by this matcher.
    *    @return  the RegexPattern for this RegexMatcher
    *    @stable ICU 2.4
    */
    virtual const RegexPattern &pattern() const;


   /**
    *    Replaces every substring of the input that matches the pattern
    *    with the given replacement string.  This is a convenience function that
    *    provides a complete find-and-replace-all operation.
    *
    *    This method first resets this matcher. It then scans the input string
    *    looking for matches of the pattern. Input that is not part of any
    *    match is left unchanged; each match is replaced in the result by the
    *    replacement string. The replacement string may contain references to
    *    capture groups.
    *
    *    @param   replacement a string containing the replacement text.
    *    @param   status      a reference to a UErrorCode to receive any errors.
    *    @return              a string containing the results of the find and replace.
    *    @stable ICU 2.4
    */
    virtual UnicodeString replaceAll(const UnicodeString &replacement, UErrorCode &status);


   /**
    *    Replaces every substring of the input that matches the pattern
    *    with the given replacement string.  This is a convenience function that
    *    provides a complete find-and-replace-all operation.
    *
    *    This method first resets this matcher. It then scans the input string
    *    looking for matches of the pattern. Input that is not part of any
    *    match is left unchanged; each match is replaced in the result by the
    *    replacement string. The replacement string may contain references to
    *    capture groups.
    *
    *    @param   replacement a string containing the replacement text.
    *    @param   dest        a mutable UText in which the results are placed.
    *                          If NULL, a new UText will be created (which may not be mutable).
    *    @param   status      a reference to a UErrorCode to receive any errors.
    *    @return              a string containing the results of the find and replace.
    *                          If a pre-allocated UText was provided, it will always be used and returned.
    *
    *    @stable ICU 4.6
    */
    virtual UText *replaceAll(UText *replacement, UText *dest, UErrorCode &status);
    

   /**
    * Replaces the first substring of the input that matches
    * the pattern with the replacement string.   This is a convenience
    * function that provides a complete find-and-replace operation.
    *
    * <p>This function first resets this RegexMatcher. It then scans the input string
    * looking for a match of the pattern. Input that is not part
    * of the match is appended directly to the result string; the match is replaced
    * in the result by the replacement string. The replacement string may contain
    * references to captured groups.</p>
    *
    * <p>The state of the matcher (the position at which a subsequent find()
    *    would begin) after completing a replaceFirst() is not specified.  The
    *    RegexMatcher should be reset before doing additional find() operations.</p>
    *
    *    @param   replacement a string containing the replacement text.
    *    @param   status      a reference to a UErrorCode to receive any errors.
    *    @return              a string containing the results of the find and replace.
    *    @stable ICU 2.4
    */
    virtual UnicodeString replaceFirst(const UnicodeString &replacement, UErrorCode &status);
    

   /**
    * Replaces the first substring of the input that matches
    * the pattern with the replacement string.   This is a convenience
    * function that provides a complete find-and-replace operation.
    *
    * <p>This function first resets this RegexMatcher. It then scans the input string
    * looking for a match of the pattern. Input that is not part
    * of the match is appended directly to the result string; the match is replaced
    * in the result by the replacement string. The replacement string may contain
    * references to captured groups.</p>
    *
    * <p>The state of the matcher (the position at which a subsequent find()
    *    would begin) after completing a replaceFirst() is not specified.  The
    *    RegexMatcher should be reset before doing additional find() operations.</p>
    *
    *    @param   replacement a string containing the replacement text.
    *    @param   dest        a mutable UText in which the results are placed.
    *                          If NULL, a new UText will be created (which may not be mutable).
    *    @param   status      a reference to a UErrorCode to receive any errors.
    *    @return              a string containing the results of the find and replace.
    *                          If a pre-allocated UText was provided, it will always be used and returned.
    *
    *    @stable ICU 4.6
    */
    virtual UText *replaceFirst(UText *replacement, UText *dest, UErrorCode &status);
    
    
   /**
    *   Implements a replace operation intended to be used as part of an
    *   incremental find-and-replace.
    *
    *   <p>The input string, starting from the end of the previous replacement and ending at
    *   the start of the current match, is appended to the destination string.  Then the
    *   replacement string is appended to the output string,
    *   including handling any substitutions of captured text.</p>
    *
    *   <p>For simple, prepackaged, non-incremental find-and-replace
    *   operations, see replaceFirst() or replaceAll().</p>
    *
    *   @param   dest        A UnicodeString to which the results of the find-and-replace are appended.
    *   @param   replacement A UnicodeString that provides the text to be substituted for
    *                        the input text that matched the regexp pattern.  The replacement
    *                        text may contain references to captured text from the
    *                        input.
    *   @param   status      A reference to a UErrorCode to receive any errors.  Possible
    *                        errors are  U_REGEX_INVALID_STATE if no match has been
    *                        attempted or the last match failed, and U_INDEX_OUTOFBOUNDS_ERROR
    *                        if the replacement text specifies a capture group that
    *                        does not exist in the pattern.
    *
    *   @return  this  RegexMatcher
    *   @stable ICU 2.4
    *
    */
    virtual RegexMatcher &appendReplacement(UnicodeString &dest,
        const UnicodeString &replacement, UErrorCode &status);
    
    
   /**
    *   Implements a replace operation intended to be used as part of an
    *   incremental find-and-replace.
    *
    *   <p>The input string, starting from the end of the previous replacement and ending at
    *   the start of the current match, is appended to the destination string.  Then the
    *   replacement string is appended to the output string,
    *   including handling any substitutions of captured text.</p>
    *
    *   <p>For simple, prepackaged, non-incremental find-and-replace
    *   operations, see replaceFirst() or replaceAll().</p>
    *
    *   @param   dest        A mutable UText to which the results of the find-and-replace are appended.
    *                         Must not be NULL.
    *   @param   replacement A UText that provides the text to be substituted for
    *                        the input text that matched the regexp pattern.  The replacement
    *                        text may contain references to captured text from the input.
    *   @param   status      A reference to a UErrorCode to receive any errors.  Possible
    *                        errors are  U_REGEX_INVALID_STATE if no match has been
    *                        attempted or the last match failed, and U_INDEX_OUTOFBOUNDS_ERROR
    *                        if the replacement text specifies a capture group that
    *                        does not exist in the pattern.
    *
    *   @return  this  RegexMatcher
    *
    *   @stable ICU 4.6
    */
    virtual RegexMatcher &appendReplacement(UText *dest,
        UText *replacement, UErrorCode &status);


   /**
    * As the final step in a find-and-replace operation, append the remainder
    * of the input string, starting at the position following the last appendReplacement(),
    * to the destination string. <code>appendTail()</code> is intended to be invoked after one
    * or more invocations of the <code>RegexMatcher::appendReplacement()</code>.
    *
    *  @param dest A UnicodeString to which the results of the find-and-replace are appended.
    *  @return  the destination string.
    *  @stable ICU 2.4
    */
    virtual UnicodeString &appendTail(UnicodeString &dest);


   /**
    * As the final step in a find-and-replace operation, append the remainder
    * of the input string, starting at the position following the last appendReplacement(),
    * to the destination string. <code>appendTail()</code> is intended to be invoked after one
    * or more invocations of the <code>RegexMatcher::appendReplacement()</code>.
    *
    *  @param dest A mutable UText to which the results of the find-and-replace are appended.
    *               Must not be NULL.
    *  @param status error cod
    *  @return  the destination string.
    *
    *  @stable ICU 4.6
    */
    virtual UText *appendTail(UText *dest, UErrorCode &status);


    /**
     * Split a string into fields.  Somewhat like split() from Perl.
     * The pattern matches identify delimiters that separate the input
     *  into fields.  The input data between the matches becomes the
     *  fields themselves.
     *
     * @param input   The string to be split into fields.  The field delimiters
     *                match the pattern (in the "this" object).  This matcher
     *                will be reset to this input string.
     * @param dest    An array of UnicodeStrings to receive the results of the split.
     *                This is an array of actual UnicodeString objects, not an
     *                array of pointers to strings.  Local (stack based) arrays can
     *                work well here.
     * @param destCapacity  The number of elements in the destination array.
     *                If the number of fields found is less than destCapacity, the
     *                extra strings in the destination array are not altered.
     *                If the number of destination strings is less than the number
     *                of fields, the trailing part of the input string, including any
     *                field delimiters, is placed in the last destination string.
     * @param status  A reference to a UErrorCode to receive any errors.
     * @return        The number of fields into which the input string was split.
     * @stable ICU 2.6
     */
    virtual int32_t  split(const UnicodeString &input,
        UnicodeString    dest[],
        int32_t          destCapacity,
        UErrorCode       &status);


    /**
     * Split a string into fields.  Somewhat like split() from Perl.
     * The pattern matches identify delimiters that separate the input
     *  into fields.  The input data between the matches becomes the
     *  fields themselves.
     *
     * @param input   The string to be split into fields.  The field delimiters
     *                match the pattern (in the "this" object).  This matcher
     *                will be reset to this input string.
     * @param dest    An array of mutable UText structs to receive the results of the split.
     *                If a field is NULL, a new UText is allocated to contain the results for
     *                that field. This new UText is not guaranteed to be mutable.
     * @param destCapacity  The number of elements in the destination array.
     *                If the number of fields found is less than destCapacity, the
     *                extra strings in the destination array are not altered.
     *                If the number of destination strings is less than the number
     *                of fields, the trailing part of the input string, including any
     *                field delimiters, is placed in the last destination string.
     * @param status  A reference to a UErrorCode to receive any errors.
     * @return        The number of fields into which the input string was split.
     *
     * @stable ICU 4.6
     */
    virtual int32_t  split(UText *input,
        UText           *dest[],
        int32_t          destCapacity,
        UErrorCode       &status);
    
  /**
    *   Set a processing time limit for match operations with this Matcher.
    *  
    *   Some patterns, when matching certain strings, can run in exponential time.
    *   For practical purposes, the match operation may appear to be in an
    *   infinite loop.
    *   When a limit is set a match operation will fail with an error if the
    *   limit is exceeded.
    *   <p>
    *   The units of the limit are steps of the match engine.
    *   Correspondence with actual processor time will depend on the speed
    *   of the processor and the details of the specific pattern, but will
    *   typically be on the order of milliseconds.
    *   <p>
    *   By default, the matching time is not limited.
    *   <p>
    *
    *   @param   limit       The limit value, or 0 for no limit.
    *   @param   status      A reference to a UErrorCode to receive any errors.
    *   @stable ICU 4.0
    */
    virtual void setTimeLimit(int32_t limit, UErrorCode &status);

  /**
    * Get the time limit, if any, for match operations made with this Matcher.
    *
    *   @return the maximum allowed time for a match, in units of processing steps.
    *   @stable ICU 4.0
    */
    virtual int32_t getTimeLimit() const;

  /**
    *  Set the amount of heap storage available for use by the match backtracking stack.
    *  The matcher is also reset, discarding any results from previous matches.
    *  <p>
    *  ICU uses a backtracking regular expression engine, with the backtrack stack
    *  maintained on the heap.  This function sets the limit to the amount of memory
    *  that can be used  for this purpose.  A backtracking stack overflow will
    *  result in an error from the match operation that caused it.
    *  <p>
    *  A limit is desirable because a malicious or poorly designed pattern can use
    *  excessive memory, potentially crashing the process.  A limit is enabled
    *  by default.
    *  <p>
    *  @param limit  The maximum size, in bytes, of the matching backtrack stack.
    *                A value of zero means no limit.
    *                The limit must be greater or equal to zero.
    *
    *  @param status   A reference to a UErrorCode to receive any errors.
    *
    *  @stable ICU 4.0
    */
    virtual void setStackLimit(int32_t  limit, UErrorCode &status);
    
  /**
    *  Get the size of the heap storage available for use by the back tracking stack.
    *
    *  @return  the maximum backtracking stack size, in bytes, or zero if the
    *           stack size is unlimited.
    *  @stable ICU 4.0
    */
    virtual int32_t  getStackLimit() const;


  /**
    * Set a callback function for use with this Matcher.
    * During matching operations the function will be called periodically,
    * giving the application the opportunity to terminate a long-running
    * match.
    *
    *    @param   callback    A pointer to the user-supplied callback function.
    *    @param   context     User context pointer.  The value supplied at the
    *                         time the callback function is set will be saved
    *                         and passed to the callback each time that it is called.
    *    @param   status      A reference to a UErrorCode to receive any errors.
    *  @stable ICU 4.0
    */
    virtual void setMatchCallback(URegexMatchCallback     *callback,
                                  const void              *context,
                                  UErrorCode              &status);


  /**
    *  Get the callback function for this URegularExpression.
    *
    *    @param   callback    Out parameter, receives a pointer to the user-supplied 
    *                         callback function.
    *    @param   context     Out parameter, receives the user context pointer that
    *                         was set when uregex_setMatchCallback() was called.
    *    @param   status      A reference to a UErrorCode to receive any errors.
    *    @stable ICU 4.0
    */
    virtual void getMatchCallback(URegexMatchCallback     *&callback,
                                  const void              *&context,
                                  UErrorCode              &status);


  /**
    * Set a progress callback function for use with find operations on this Matcher.
    * During find operations, the callback will be invoked after each return from a
    * match attempt, giving the application the opportunity to terminate a long-running
    * find operation.
    *
    *    @param   callback    A pointer to the user-supplied callback function.
    *    @param   context     User context pointer.  The value supplied at the
    *                         time the callback function is set will be saved
    *                         and passed to the callback each time that it is called.
    *    @param   status      A reference to a UErrorCode to receive any errors.
    *    @stable ICU 4.6
    */
    virtual void setFindProgressCallback(URegexFindProgressCallback      *callback,
                                              const void                              *context,
                                              UErrorCode                              &status);


  /**
    *  Get the find progress callback function for this URegularExpression.
    *
    *    @param   callback    Out parameter, receives a pointer to the user-supplied 
    *                         callback function.
    *    @param   context     Out parameter, receives the user context pointer that
    *                         was set when uregex_setFindProgressCallback() was called.
    *    @param   status      A reference to a UErrorCode to receive any errors.
    *    @stable ICU 4.6
    */
    virtual void getFindProgressCallback(URegexFindProgressCallback      *&callback,
                                              const void                      *&context,
                                              UErrorCode                      &status);

#ifndef U_HIDE_INTERNAL_API
   /**
     *   setTrace   Debug function, enable/disable tracing of the matching engine.
     *              For internal ICU development use only.  DO NO USE!!!!
     *   @internal
     */
    void setTrace(UBool state);
#endif  /* U_HIDE_INTERNAL_API */

    /**
    * ICU "poor man's RTTI", returns a UClassID for this class.
    *
    * @stable ICU 2.2
    */
    static UClassID U_EXPORT2 getStaticClassID();

    /**
     * ICU "poor man's RTTI", returns a UClassID for the actual class.
     *
     * @stable ICU 2.2
     */
    virtual UClassID getDynamicClassID() const;

private:
    // Constructors and other object boilerplate are private.
    // Instances of RegexMatcher can not be assigned, copied, cloned, etc.
    RegexMatcher();                  // default constructor not implemented
    RegexMatcher(const RegexPattern *pat);
    RegexMatcher(const RegexMatcher &other);
    RegexMatcher &operator =(const RegexMatcher &rhs);
    void init(UErrorCode &status);                      // Common initialization
    void init2(UText *t, UErrorCode &e);  // Common initialization, part 2.

    friend class RegexPattern;
    friend class RegexCImpl;
public:
#ifndef U_HIDE_INTERNAL_API
    /** @internal  */
    void resetPreserveRegion();  // Reset matcher state, but preserve any region.
#endif  /* U_HIDE_INTERNAL_API */
private:

    //
    //  MatchAt   This is the internal interface to the match engine itself.
    //            Match status comes back in matcher member variables.
    //
    void                 MatchAt(int64_t startIdx, UBool toEnd, UErrorCode &status);
    inline void          backTrack(int64_t &inputIdx, int32_t &patIdx);
    UBool                isWordBoundary(int64_t pos);         // perform Perl-like  \b test
    UBool                isUWordBoundary(int64_t pos);        // perform RBBI based \b test
    REStackFrame        *resetStack();
    inline REStackFrame *StateSave(REStackFrame *fp, int64_t savePatIdx, UErrorCode &status);
    void                 IncrementTime(UErrorCode &status);

    // Call user find callback function, if set. Return TRUE if operation should be interrupted.
    inline UBool         findProgressInterrupt(int64_t matchIndex, UErrorCode &status);
    
    int64_t              appendGroup(int32_t groupNum, UText *dest, UErrorCode &status) const;
    
    UBool                findUsingChunk(UErrorCode &status);
    void                 MatchChunkAt(int32_t startIdx, UBool toEnd, UErrorCode &status);
    UBool                isChunkWordBoundary(int32_t pos);

    const RegexPattern  *fPattern;
    RegexPattern        *fPatternOwned;    // Non-NULL if this matcher owns the pattern, and
                                           //   should delete it when through.

    const UnicodeString *fInput;           // The string being matched. Only used for input()
    UText               *fInputText;       // The text being matched. Is never NULL.
    UText               *fAltInputText;    // A shallow copy of the text being matched.
                                           //   Only created if the pattern contains backreferences.
    int64_t              fInputLength;     // Full length of the input text.
    int32_t              fFrameSize;       // The size of a frame in the backtrack stack.
    
    int64_t              fRegionStart;     // Start of the input region, default = 0.
    int64_t              fRegionLimit;     // End of input region, default to input.length.
    
    int64_t              fAnchorStart;     // Region bounds for anchoring operations (^ or $).
    int64_t              fAnchorLimit;     //   See useAnchoringBounds
    
    int64_t              fLookStart;       // Region bounds for look-ahead/behind and
    int64_t              fLookLimit;       //   and other boundary tests.  See
                                           //   useTransparentBounds

    int64_t              fActiveStart;     // Currently active bounds for matching.
    int64_t              fActiveLimit;     //   Usually is the same as region, but
                                           //   is changed to fLookStart/Limit when
                                           //   entering look around regions.

    UBool                fTransparentBounds;  // True if using transparent bounds.
    UBool                fAnchoringBounds; // True if using anchoring bounds.

    UBool                fMatch;           // True if the last attempted match was successful.
    int64_t              fMatchStart;      // Position of the start of the most recent match
    int64_t              fMatchEnd;        // First position after the end of the most recent match
                                           //   Zero if no previous match, even when a region
                                           //   is active.
    int64_t              fLastMatchEnd;    // First position after the end of the previous match,
                                           //   or -1 if there was no previous match.
    int64_t              fAppendPosition;  // First position after the end of the previous
                                           //   appendReplacement().  As described by the
                                           //   JavaDoc for Java Matcher, where it is called 
                                           //   "append position"
    UBool                fHitEnd;          // True if the last match touched the end of input.
    UBool                fRequireEnd;      // True if the last match required end-of-input
                                           //    (matched $ or Z)

    UVector64           *fStack;
    REStackFrame        *fFrame;           // After finding a match, the last active stack frame,
                                           //   which will contain the capture group results.
                                           //   NOT valid while match engine is running.

    int64_t             *fData;            // Data area for use by the compiled pattern.
    int64_t             fSmallData[8];     //   Use this for data if it's enough.

    int32_t             fTimeLimit;        // Max time (in arbitrary steps) to let the
                                           //   match engine run.  Zero for unlimited.
    
    int32_t             fTime;             // Match time, accumulates while matching.
    int32_t             fTickCounter;      // Low bits counter for time.  Counts down StateSaves.
                                           //   Kept separately from fTime to keep as much
                                           //   code as possible out of the inline
                                           //   StateSave function.

    int32_t             fStackLimit;       // Maximum memory size to use for the backtrack
                                           //   stack, in bytes.  Zero for unlimited.

    URegexMatchCallback *fCallbackFn;       // Pointer to match progress callback funct.
                                           //   NULL if there is no callback.
    const void         *fCallbackContext;  // User Context ptr for callback function.

    URegexFindProgressCallback  *fFindProgressCallbackFn;  // Pointer to match progress callback funct.
                                                           //   NULL if there is no callback.
    const void         *fFindProgressCallbackContext;      // User Context ptr for callback function.


    UBool               fInputUniStrMaybeMutable;  // Set when fInputText wraps a UnicodeString that may be mutable - compatibility.

    UBool               fTraceDebug;       // Set true for debug tracing of match engine.

    UErrorCode          fDeferredStatus;   // Save error state that cannot be immediately
                                           //   reported, or that permanently disables this matcher.

    RuleBasedBreakIterator  *fWordBreakItr;
};

U_NAMESPACE_END
#endif  // UCONFIG_NO_REGULAR_EXPRESSIONS
#endif