DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Mercurial (b6d82b1a6b02)

VCS Links

Line Code
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
// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
*******************************************************************************
*   Copyright (C) 2010-2015, International Business Machines
*   Corporation and others.  All Rights Reserved.
*******************************************************************************
*   file name:  uts46.cpp
*   encoding:   UTF-8
*   tab size:   8 (not used)
*   indentation:4
*
*   created on: 2010mar09
*   created by: Markus W. Scherer
*/

#include "unicode/utypes.h"

#if !UCONFIG_NO_IDNA

#include "unicode/idna.h"
#include "unicode/normalizer2.h"
#include "unicode/uscript.h"
#include "unicode/ustring.h"
#include "unicode/utf16.h"
#include "cmemory.h"
#include "cstring.h"
#include "punycode.h"
#include "ubidi_props.h"
#include "ustr_imp.h"

// Note about tests for UIDNA_ERROR_DOMAIN_NAME_TOO_LONG:
//
// The domain name length limit is 255 octets in an internal DNS representation
// where the last ("root") label is the empty label
// represented by length byte 0 alone.
// In a conventional string, this translates to 253 characters, or 254
// if there is a trailing dot for the root label.

U_NAMESPACE_BEGIN

// Severe errors which usually result in a U+FFFD replacement character in the result string.
const uint32_t severeErrors=
    UIDNA_ERROR_LEADING_COMBINING_MARK|
    UIDNA_ERROR_DISALLOWED|
    UIDNA_ERROR_PUNYCODE|
    UIDNA_ERROR_LABEL_HAS_DOT|
    UIDNA_ERROR_INVALID_ACE_LABEL;

static inline UBool
isASCIIString(const UnicodeString &dest) {
    const UChar *s=dest.getBuffer();
    const UChar *limit=s+dest.length();
    while(s<limit) {
        if(*s++>0x7f) {
            return FALSE;
        }
    }
    return TRUE;
}

static UBool
isASCIIOkBiDi(const UChar *s, int32_t length);

static UBool
isASCIIOkBiDi(const char *s, int32_t length);

// IDNA class default implementations -------------------------------------- ***

IDNA::~IDNA() {}

void
IDNA::labelToASCII_UTF8(StringPiece label, ByteSink &dest,
                        IDNAInfo &info, UErrorCode &errorCode) const {
    if(U_SUCCESS(errorCode)) {
        UnicodeString destString;
        labelToASCII(UnicodeString::fromUTF8(label), destString,
                     info, errorCode).toUTF8(dest);
    }
}

void
IDNA::labelToUnicodeUTF8(StringPiece label, ByteSink &dest,
                         IDNAInfo &info, UErrorCode &errorCode) const {
    if(U_SUCCESS(errorCode)) {
        UnicodeString destString;
        labelToUnicode(UnicodeString::fromUTF8(label), destString,
                       info, errorCode).toUTF8(dest);
    }
}

void
IDNA::nameToASCII_UTF8(StringPiece name, ByteSink &dest,
                       IDNAInfo &info, UErrorCode &errorCode) const {
    if(U_SUCCESS(errorCode)) {
        UnicodeString destString;
        nameToASCII(UnicodeString::fromUTF8(name), destString,
                    info, errorCode).toUTF8(dest);
    }
}

void
IDNA::nameToUnicodeUTF8(StringPiece name, ByteSink &dest,
                        IDNAInfo &info, UErrorCode &errorCode) const {
    if(U_SUCCESS(errorCode)) {
        UnicodeString destString;
        nameToUnicode(UnicodeString::fromUTF8(name), destString,
                      info, errorCode).toUTF8(dest);
    }
}

// UTS46 class declaration ------------------------------------------------- ***

class UTS46 : public IDNA {
public:
    UTS46(uint32_t options, UErrorCode &errorCode);
    virtual ~UTS46();

    virtual UnicodeString &
    labelToASCII(const UnicodeString &label, UnicodeString &dest,
                 IDNAInfo &info, UErrorCode &errorCode) const;

    virtual UnicodeString &
    labelToUnicode(const UnicodeString &label, UnicodeString &dest,
                   IDNAInfo &info, UErrorCode &errorCode) const;

    virtual UnicodeString &
    nameToASCII(const UnicodeString &name, UnicodeString &dest,
                IDNAInfo &info, UErrorCode &errorCode) const;

    virtual UnicodeString &
    nameToUnicode(const UnicodeString &name, UnicodeString &dest,
                  IDNAInfo &info, UErrorCode &errorCode) const;

    virtual void
    labelToASCII_UTF8(StringPiece label, ByteSink &dest,
                      IDNAInfo &info, UErrorCode &errorCode) const;

    virtual void
    labelToUnicodeUTF8(StringPiece label, ByteSink &dest,
                       IDNAInfo &info, UErrorCode &errorCode) const;

    virtual void
    nameToASCII_UTF8(StringPiece name, ByteSink &dest,
                     IDNAInfo &info, UErrorCode &errorCode) const;

    virtual void
    nameToUnicodeUTF8(StringPiece name, ByteSink &dest,
                      IDNAInfo &info, UErrorCode &errorCode) const;

private:
    UnicodeString &
    process(const UnicodeString &src,
            UBool isLabel, UBool toASCII,
            UnicodeString &dest,
            IDNAInfo &info, UErrorCode &errorCode) const;

    void
    processUTF8(StringPiece src,
                UBool isLabel, UBool toASCII,
                ByteSink &dest,
                IDNAInfo &info, UErrorCode &errorCode) const;

    UnicodeString &
    processUnicode(const UnicodeString &src,
                   int32_t labelStart, int32_t mappingStart,
                   UBool isLabel, UBool toASCII,
                   UnicodeString &dest,
                   IDNAInfo &info, UErrorCode &errorCode) const;

    // returns the new dest.length()
    int32_t
    mapDevChars(UnicodeString &dest, int32_t labelStart, int32_t mappingStart,
                UErrorCode &errorCode) const;

    // returns the new label length
    int32_t
    processLabel(UnicodeString &dest,
                 int32_t labelStart, int32_t labelLength,
                 UBool toASCII,
                 IDNAInfo &info, UErrorCode &errorCode) const;
    int32_t
    markBadACELabel(UnicodeString &dest,
                    int32_t labelStart, int32_t labelLength,
                    UBool toASCII, IDNAInfo &info, UErrorCode &errorCode) const;

    void
    checkLabelBiDi(const UChar *label, int32_t labelLength, IDNAInfo &info) const;

    UBool
    isLabelOkContextJ(const UChar *label, int32_t labelLength) const;

    void
    checkLabelContextO(const UChar *label, int32_t labelLength, IDNAInfo &info) const;

    const Normalizer2 &uts46Norm2;  // uts46.nrm
    uint32_t options;
};

IDNA *
IDNA::createUTS46Instance(uint32_t options, UErrorCode &errorCode) {
    if(U_SUCCESS(errorCode)) {
        IDNA *idna=new UTS46(options, errorCode);
        if(idna==NULL) {
            errorCode=U_MEMORY_ALLOCATION_ERROR;
        } else if(U_FAILURE(errorCode)) {
            delete idna;
            idna=NULL;
        }
        return idna;
    } else {
        return NULL;
    }
}

// UTS46 implementation ---------------------------------------------------- ***

UTS46::UTS46(uint32_t opt, UErrorCode &errorCode)
        : uts46Norm2(*Normalizer2::getInstance(NULL, "uts46", UNORM2_COMPOSE, errorCode)),
          options(opt) {}

UTS46::~UTS46() {}

UnicodeString &
UTS46::labelToASCII(const UnicodeString &label, UnicodeString &dest,
                    IDNAInfo &info, UErrorCode &errorCode) const {
    return process(label, TRUE, TRUE, dest, info, errorCode);
}

UnicodeString &
UTS46::labelToUnicode(const UnicodeString &label, UnicodeString &dest,
                      IDNAInfo &info, UErrorCode &errorCode) const {
    return process(label, TRUE, FALSE, dest, info, errorCode);
}

UnicodeString &
UTS46::nameToASCII(const UnicodeString &name, UnicodeString &dest,
                   IDNAInfo &info, UErrorCode &errorCode) const {
    process(name, FALSE, TRUE, dest, info, errorCode);
    if( dest.length()>=254 && (info.errors&UIDNA_ERROR_DOMAIN_NAME_TOO_LONG)==0 &&
        isASCIIString(dest) &&
        (dest.length()>254 || dest[253]!=0x2e)
    ) {
        info.errors|=UIDNA_ERROR_DOMAIN_NAME_TOO_LONG;
    }
    return dest;
}

UnicodeString &
UTS46::nameToUnicode(const UnicodeString &name, UnicodeString &dest,
                     IDNAInfo &info, UErrorCode &errorCode) const {
    return process(name, FALSE, FALSE, dest, info, errorCode);
}

void
UTS46::labelToASCII_UTF8(StringPiece label, ByteSink &dest,
                         IDNAInfo &info, UErrorCode &errorCode) const {
    processUTF8(label, TRUE, TRUE, dest, info, errorCode);
}

void
UTS46::labelToUnicodeUTF8(StringPiece label, ByteSink &dest,
                          IDNAInfo &info, UErrorCode &errorCode) const {
    processUTF8(label, TRUE, FALSE, dest, info, errorCode);
}

void
UTS46::nameToASCII_UTF8(StringPiece name, ByteSink &dest,
                        IDNAInfo &info, UErrorCode &errorCode) const {
    processUTF8(name, FALSE, TRUE, dest, info, errorCode);
}

void
UTS46::nameToUnicodeUTF8(StringPiece name, ByteSink &dest,
                         IDNAInfo &info, UErrorCode &errorCode) const {
    processUTF8(name, FALSE, FALSE, dest, info, errorCode);
}

// UTS #46 data for ASCII characters.
// The normalizer (using uts46.nrm) maps uppercase ASCII letters to lowercase
// and passes through all other ASCII characters.
// If UIDNA_USE_STD3_RULES is set, then non-LDH characters are disallowed
// using this data.
// The ASCII fastpath also uses this data.
// Values: -1=disallowed  0==valid  1==mapped (lowercase)
static const int8_t asciiData[128]={
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    // 002D..002E; valid  #  HYPHEN-MINUS..FULL STOP
    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  0,  0, -1,
    // 0030..0039; valid  #  DIGIT ZERO..DIGIT NINE
     0,  0,  0,  0,  0,  0,  0,  0,  0,  0, -1, -1, -1, -1, -1, -1,
    // 0041..005A; mapped  #  LATIN CAPITAL LETTER A..LATIN CAPITAL LETTER Z
    -1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
     1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1, -1, -1, -1, -1, -1,
    // 0061..007A; valid  #  LATIN SMALL LETTER A..LATIN SMALL LETTER Z
    -1,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0, -1, -1, -1, -1, -1
};

UnicodeString &
UTS46::process(const UnicodeString &src,
               UBool isLabel, UBool toASCII,
               UnicodeString &dest,
               IDNAInfo &info, UErrorCode &errorCode) const {
    // uts46Norm2.normalize() would do all of this error checking and setup,
    // but with the ASCII fastpath we do not always call it, and do not
    // call it first.
    if(U_FAILURE(errorCode)) {
        dest.setToBogus();
        return dest;
    }
    const UChar *srcArray=src.getBuffer();
    if(&dest==&src || srcArray==NULL) {
        errorCode=U_ILLEGAL_ARGUMENT_ERROR;
        dest.setToBogus();
        return dest;
    }
    // Arguments are fine, reset output values.
    dest.remove();
    info.reset();
    int32_t srcLength=src.length();
    if(srcLength==0) {
        info.errors|=UIDNA_ERROR_EMPTY_LABEL;
        return dest;
    }
    UChar *destArray=dest.getBuffer(srcLength);
    if(destArray==NULL) {
        errorCode=U_MEMORY_ALLOCATION_ERROR;
        return dest;
    }
    // ASCII fastpath
    UBool disallowNonLDHDot=(options&UIDNA_USE_STD3_RULES)!=0;
    int32_t labelStart=0;
    int32_t i;
    for(i=0;; ++i) {
        if(i==srcLength) {
            if(toASCII) {
                if((i-labelStart)>63) {
                    info.labelErrors|=UIDNA_ERROR_LABEL_TOO_LONG;
                }
                // There is a trailing dot if labelStart==i.
                if(!isLabel && i>=254 && (i>254 || labelStart<i)) {
                    info.errors|=UIDNA_ERROR_DOMAIN_NAME_TOO_LONG;
                }
            }
            info.errors|=info.labelErrors;
            dest.releaseBuffer(i);
            return dest;
        }
        UChar c=srcArray[i];
        if(c>0x7f) {
            break;
        }
        int cData=asciiData[c];
        if(cData>0) {
            destArray[i]=c+0x20;  // Lowercase an uppercase ASCII letter.
        } else if(cData<0 && disallowNonLDHDot) {
            break;  // Replacing with U+FFFD can be complicated for toASCII.
        } else {
            destArray[i]=c;
            if(c==0x2d) {  // hyphen
                if(i==(labelStart+3) && srcArray[i-1]==0x2d) {
                    // "??--..." is Punycode or forbidden.
                    ++i;  // '-' was copied to dest already
                    break;
                }
                if(i==labelStart) {
                    // label starts with "-"
                    info.labelErrors|=UIDNA_ERROR_LEADING_HYPHEN;
                }
                if((i+1)==srcLength || srcArray[i+1]==0x2e) {
                    // label ends with "-"
                    info.labelErrors|=UIDNA_ERROR_TRAILING_HYPHEN;
                }
            } else if(c==0x2e) {  // dot
                if(isLabel) {
                    // Replacing with U+FFFD can be complicated for toASCII.
                    ++i;  // '.' was copied to dest already
                    break;
                }
                if(i==labelStart) {
                    info.labelErrors|=UIDNA_ERROR_EMPTY_LABEL;
                }
                if(toASCII && (i-labelStart)>63) {
                    info.labelErrors|=UIDNA_ERROR_LABEL_TOO_LONG;
                }
                info.errors|=info.labelErrors;
                info.labelErrors=0;
                labelStart=i+1;
            }
        }
    }
    info.errors|=info.labelErrors;
    dest.releaseBuffer(i);
    processUnicode(src, labelStart, i, isLabel, toASCII, dest, info, errorCode);
    if( info.isBiDi && U_SUCCESS(errorCode) && (info.errors&severeErrors)==0 &&
        (!info.isOkBiDi || (labelStart>0 && !isASCIIOkBiDi(dest.getBuffer(), labelStart)))
    ) {
        info.errors|=UIDNA_ERROR_BIDI;
    }
    return dest;
}

void
UTS46::processUTF8(StringPiece src,
                   UBool isLabel, UBool toASCII,
                   ByteSink &dest,
                   IDNAInfo &info, UErrorCode &errorCode) const {
    if(U_FAILURE(errorCode)) {
        return;
    }
    const char *srcArray=src.data();
    int32_t srcLength=src.length();
    if(srcArray==NULL && srcLength!=0) {
        errorCode=U_ILLEGAL_ARGUMENT_ERROR;
        return;
    }
    // Arguments are fine, reset output values.
    info.reset();
    if(srcLength==0) {
        info.errors|=UIDNA_ERROR_EMPTY_LABEL;
        dest.Flush();
        return;
    }
    UnicodeString destString;
    int32_t labelStart=0;
    if(srcLength<=256) {  // length of stackArray[]
        // ASCII fastpath
        char stackArray[256];
        int32_t destCapacity;
        char *destArray=dest.GetAppendBuffer(srcLength, srcLength+20,
                                             stackArray, UPRV_LENGTHOF(stackArray), &destCapacity);
        UBool disallowNonLDHDot=(options&UIDNA_USE_STD3_RULES)!=0;
        int32_t i;
        for(i=0;; ++i) {
            if(i==srcLength) {
                if(toASCII) {
                    if((i-labelStart)>63) {
                        info.labelErrors|=UIDNA_ERROR_LABEL_TOO_LONG;
                    }
                    // There is a trailing dot if labelStart==i.
                    if(!isLabel && i>=254 && (i>254 || labelStart<i)) {
                        info.errors|=UIDNA_ERROR_DOMAIN_NAME_TOO_LONG;
                    }
                }
                info.errors|=info.labelErrors;
                dest.Append(destArray, i);
                dest.Flush();
                return;
            }
            char c=srcArray[i];
            if((int8_t)c<0) {  // (uint8_t)c>0x7f
                break;
            }
            int cData=asciiData[(int)c];  // Cast: gcc warns about indexing with a char.
            if(cData>0) {
                destArray[i]=c+0x20;  // Lowercase an uppercase ASCII letter.
            } else if(cData<0 && disallowNonLDHDot) {
                break;  // Replacing with U+FFFD can be complicated for toASCII.
            } else {
                destArray[i]=c;
                if(c==0x2d) {  // hyphen
                    if(i==(labelStart+3) && srcArray[i-1]==0x2d) {
                        // "??--..." is Punycode or forbidden.
                        break;
                    }
                    if(i==labelStart) {
                        // label starts with "-"
                        info.labelErrors|=UIDNA_ERROR_LEADING_HYPHEN;
                    }
                    if((i+1)==srcLength || srcArray[i+1]==0x2e) {
                        // label ends with "-"
                        info.labelErrors|=UIDNA_ERROR_TRAILING_HYPHEN;
                    }
                } else if(c==0x2e) {  // dot
                    if(isLabel) {
                        break;  // Replacing with U+FFFD can be complicated for toASCII.
                    }
                    if(i==labelStart) {
                        info.labelErrors|=UIDNA_ERROR_EMPTY_LABEL;
                    }
                    if(toASCII && (i-labelStart)>63) {
                        info.labelErrors|=UIDNA_ERROR_LABEL_TOO_LONG;
                    }
                    info.errors|=info.labelErrors;
                    info.labelErrors=0;
                    labelStart=i+1;
                }
            }
        }
        info.errors|=info.labelErrors;
        // Convert the processed ASCII prefix of the current label to UTF-16.
        int32_t mappingStart=i-labelStart;
        destString=UnicodeString::fromUTF8(StringPiece(destArray+labelStart, mappingStart));
        // Output the previous ASCII labels and process the rest of src in UTF-16.
        dest.Append(destArray, labelStart);
        processUnicode(UnicodeString::fromUTF8(StringPiece(src, labelStart)), 0, mappingStart,
                       isLabel, toASCII,
                       destString, info, errorCode);
    } else {
        // src is too long for the ASCII fastpath implementation.
        processUnicode(UnicodeString::fromUTF8(src), 0, 0,
                       isLabel, toASCII,
                       destString, info, errorCode);
    }
    destString.toUTF8(dest);  // calls dest.Flush()
    if(toASCII && !isLabel) {
        // length==labelStart==254 means that there is a trailing dot (ok) and
        // destString is empty (do not index at 253-labelStart).
        int32_t length=labelStart+destString.length();
        if( length>=254 && isASCIIString(destString) &&
            (length>254 ||
             (labelStart<254 && destString[253-labelStart]!=0x2e))
        ) {
            info.errors|=UIDNA_ERROR_DOMAIN_NAME_TOO_LONG;
        }
    }
    if( info.isBiDi && U_SUCCESS(errorCode) && (info.errors&severeErrors)==0 &&
        (!info.isOkBiDi || (labelStart>0 && !isASCIIOkBiDi(srcArray, labelStart)))
    ) {
        info.errors|=UIDNA_ERROR_BIDI;
    }
}

UnicodeString &
UTS46::processUnicode(const UnicodeString &src,
                      int32_t labelStart, int32_t mappingStart,
                      UBool isLabel, UBool toASCII,
                      UnicodeString &dest,
                      IDNAInfo &info, UErrorCode &errorCode) const {
    if(mappingStart==0) {
        uts46Norm2.normalize(src, dest, errorCode);
    } else {
        uts46Norm2.normalizeSecondAndAppend(dest, src.tempSubString(mappingStart), errorCode);
    }
    if(U_FAILURE(errorCode)) {
        return dest;
    }
    UBool doMapDevChars=
        toASCII ? (options&UIDNA_NONTRANSITIONAL_TO_ASCII)==0 :
                  (options&UIDNA_NONTRANSITIONAL_TO_UNICODE)==0;
    const UChar *destArray=dest.getBuffer();
    int32_t destLength=dest.length();
    int32_t labelLimit=labelStart;
    while(labelLimit<destLength) {
        UChar c=destArray[labelLimit];
        if(c==0x2e && !isLabel) {
            int32_t labelLength=labelLimit-labelStart;
            int32_t newLength=processLabel(dest, labelStart, labelLength,
                                            toASCII, info, errorCode);
            info.errors|=info.labelErrors;
            info.labelErrors=0;
            if(U_FAILURE(errorCode)) {
                return dest;
            }
            destArray=dest.getBuffer();
            destLength+=newLength-labelLength;
            labelLimit=labelStart+=newLength+1;
            continue;
        } else if(c<0xdf) {
            // pass
        } else if(c<=0x200d && (c==0xdf || c==0x3c2 || c>=0x200c)) {
            info.isTransDiff=TRUE;
            if(doMapDevChars) {
                destLength=mapDevChars(dest, labelStart, labelLimit, errorCode);
                if(U_FAILURE(errorCode)) {
                    return dest;
                }
                destArray=dest.getBuffer();
                // All deviation characters have been mapped, no need to check for them again.
                doMapDevChars=FALSE;
                // Do not increment labelLimit in case c was removed.
                continue;
            }
        } else if(U16_IS_SURROGATE(c)) {
            if(U16_IS_SURROGATE_LEAD(c) ?
                    (labelLimit+1)==destLength || !U16_IS_TRAIL(destArray[labelLimit+1]) :
                    labelLimit==labelStart || !U16_IS_LEAD(destArray[labelLimit-1])) {
                // Map an unpaired surrogate to U+FFFD before normalization so that when
                // that removes characters we do not turn two unpaired ones into a pair.
                info.labelErrors|=UIDNA_ERROR_DISALLOWED;
                dest.setCharAt(labelLimit, 0xfffd);
                destArray=dest.getBuffer();
            }
        }
        ++labelLimit;
    }
    // Permit an empty label at the end (0<labelStart==labelLimit==destLength is ok)
    // but not an empty label elsewhere nor a completely empty domain name.
    // processLabel() sets UIDNA_ERROR_EMPTY_LABEL when labelLength==0.
    if(0==labelStart || labelStart<labelLimit) {
        processLabel(dest, labelStart, labelLimit-labelStart,
                      toASCII, info, errorCode);
        info.errors|=info.labelErrors;
    }
    return dest;
}

int32_t
UTS46::mapDevChars(UnicodeString &dest, int32_t labelStart, int32_t mappingStart,
                   UErrorCode &errorCode) const {
    if(U_FAILURE(errorCode)) {
        return 0;
    }
    int32_t length=dest.length();
    UChar *s=dest.getBuffer(dest[mappingStart]==0xdf ? length+1 : length);
    if(s==NULL) {
        errorCode=U_MEMORY_ALLOCATION_ERROR;
        return length;
    }
    int32_t capacity=dest.getCapacity();
    UBool didMapDevChars=FALSE;
    int32_t readIndex=mappingStart, writeIndex=mappingStart;
    do {
        UChar c=s[readIndex++];
        switch(c) {
        case 0xdf:
            // Map sharp s to ss.
            didMapDevChars=TRUE;
            s[writeIndex++]=0x73;  // Replace sharp s with first s.
            // Insert second s and account for possible buffer reallocation.
            if(writeIndex==readIndex) {
                if(length==capacity) {
                    dest.releaseBuffer(length);
                    s=dest.getBuffer(length+1);
                    if(s==NULL) {
                        errorCode=U_MEMORY_ALLOCATION_ERROR;
                        return length;
                    }
                    capacity=dest.getCapacity();
                }
                u_memmove(s+writeIndex+1, s+writeIndex, length-writeIndex);
                ++readIndex;
            }
            s[writeIndex++]=0x73;
            ++length;
            break;
        case 0x3c2:  // Map final sigma to nonfinal sigma.
            didMapDevChars=TRUE;
            s[writeIndex++]=0x3c3;
            break;
        case 0x200c:  // Ignore/remove ZWNJ.
        case 0x200d:  // Ignore/remove ZWJ.
            didMapDevChars=TRUE;
            --length;
            break;
        default:
            // Only really necessary if writeIndex was different from readIndex.
            s[writeIndex++]=c;
            break;
        }
    } while(writeIndex<length);
    dest.releaseBuffer(length);
    if(didMapDevChars) {
        // Mapping deviation characters might have resulted in an un-NFC string.
        // We could use either the NFC or the UTS #46 normalizer.
        // By using the UTS #46 normalizer again, we avoid having to load a second .nrm data file.
        UnicodeString normalized;
        uts46Norm2.normalize(dest.tempSubString(labelStart), normalized, errorCode);
        if(U_SUCCESS(errorCode)) {
            dest.replace(labelStart, 0x7fffffff, normalized);
            if(dest.isBogus()) {
                errorCode=U_MEMORY_ALLOCATION_ERROR;
            }
            return dest.length();
        }
    }
    return length;
}

// Some non-ASCII characters are equivalent to sequences with
// non-LDH ASCII characters. To find them:
// grep disallowed_STD3_valid IdnaMappingTable.txt (or uts46.txt)
static inline UBool
isNonASCIIDisallowedSTD3Valid(UChar32 c) {
    return c==0x2260 || c==0x226E || c==0x226F;
}

// Replace the label in dest with the label string, if the label was modified.
// If &label==&dest then the label was modified in-place and labelLength
// is the new label length, different from label.length().
// If &label!=&dest then labelLength==label.length().
// Returns labelLength (= the new label length).
static int32_t
replaceLabel(UnicodeString &dest, int32_t destLabelStart, int32_t destLabelLength,
             const UnicodeString &label, int32_t labelLength, UErrorCode &errorCode) {
    if(U_FAILURE(errorCode)) {
        return 0;
    }
    if(&label!=&dest) {
        dest.replace(destLabelStart, destLabelLength, label);
        if(dest.isBogus()) {
            errorCode=U_MEMORY_ALLOCATION_ERROR;
            return 0;
        }
    }
    return labelLength;
}

int32_t
UTS46::processLabel(UnicodeString &dest,
                    int32_t labelStart, int32_t labelLength,
                    UBool toASCII,
                    IDNAInfo &info, UErrorCode &errorCode) const {
    if(U_FAILURE(errorCode)) {
        return 0;
    }
    UnicodeString fromPunycode;
    UnicodeString *labelString;
    const UChar *label=dest.getBuffer()+labelStart;
    int32_t destLabelStart=labelStart;
    int32_t destLabelLength=labelLength;
    UBool wasPunycode;
    if(labelLength>=4 && label[0]==0x78 && label[1]==0x6e && label[2]==0x2d && label[3]==0x2d) {
        // Label starts with "xn--", try to un-Punycode it.
        wasPunycode=TRUE;
        UChar *unicodeBuffer=fromPunycode.getBuffer(-1);  // capacity==-1: most labels should fit
        if(unicodeBuffer==NULL) {
            // Should never occur if we used capacity==-1 which uses the internal buffer.
            errorCode=U_MEMORY_ALLOCATION_ERROR;
            return labelLength;
        }
        UErrorCode punycodeErrorCode=U_ZERO_ERROR;
        int32_t unicodeLength=u_strFromPunycode(label+4, labelLength-4,
                                                unicodeBuffer, fromPunycode.getCapacity(),
                                                NULL, &punycodeErrorCode);
        if(punycodeErrorCode==U_BUFFER_OVERFLOW_ERROR) {
            fromPunycode.releaseBuffer(0);
            unicodeBuffer=fromPunycode.getBuffer(unicodeLength);
            if(unicodeBuffer==NULL) {
                errorCode=U_MEMORY_ALLOCATION_ERROR;
                return labelLength;
            }
            punycodeErrorCode=U_ZERO_ERROR;
            unicodeLength=u_strFromPunycode(label+4, labelLength-4,
                                            unicodeBuffer, fromPunycode.getCapacity(),
                                            NULL, &punycodeErrorCode);
        }
        fromPunycode.releaseBuffer(unicodeLength);
        if(U_FAILURE(punycodeErrorCode)) {
            info.labelErrors|=UIDNA_ERROR_PUNYCODE;
            return markBadACELabel(dest, labelStart, labelLength, toASCII, info, errorCode);
        }
        // Check for NFC, and for characters that are not
        // valid or deviation characters according to the normalizer.
        // If there is something wrong, then the string will change.
        // Note that the normalizer passes through non-LDH ASCII and deviation characters.
        // Deviation characters are ok in Punycode even in transitional processing.
        // In the code further below, if we find non-LDH ASCII and we have UIDNA_USE_STD3_RULES
        // then we will set UIDNA_ERROR_INVALID_ACE_LABEL there too.
        UBool isValid=uts46Norm2.isNormalized(fromPunycode, errorCode);
        if(U_FAILURE(errorCode)) {
            return labelLength;
        }
        if(!isValid) {
            info.labelErrors|=UIDNA_ERROR_INVALID_ACE_LABEL;
            return markBadACELabel(dest, labelStart, labelLength, toASCII, info, errorCode);
        }
        labelString=&fromPunycode;
        label=fromPunycode.getBuffer();
        labelStart=0;
        labelLength=fromPunycode.length();
    } else {
        wasPunycode=FALSE;
        labelString=&dest;
    }
    // Validity check
    if(labelLength==0) {
        info.labelErrors|=UIDNA_ERROR_EMPTY_LABEL;
        return replaceLabel(dest, destLabelStart, destLabelLength,
                            *labelString, labelLength, errorCode);
    }
    // labelLength>0
    if(labelLength>=4 && label[2]==0x2d && label[3]==0x2d) {
        // label starts with "??--"
        info.labelErrors|=UIDNA_ERROR_HYPHEN_3_4;
    }
    if(label[0]==0x2d) {
        // label starts with "-"
        info.labelErrors|=UIDNA_ERROR_LEADING_HYPHEN;
    }
    if(label[labelLength-1]==0x2d) {
        // label ends with "-"
        info.labelErrors|=UIDNA_ERROR_TRAILING_HYPHEN;
    }
    // If the label was not a Punycode label, then it was the result of
    // mapping, normalization and label segmentation.
    // If the label was in Punycode, then we mapped it again above
    // and checked its validity.
    // Now we handle the STD3 restriction to LDH characters (if set)
    // and we look for U+FFFD which indicates disallowed characters
    // in a non-Punycode label or U+FFFD itself in a Punycode label.
    // We also check for dots which can come from the input to a single-label function.
    // Ok to cast away const because we own the UnicodeString.
    UChar *s=(UChar *)label;
    const UChar *limit=label+labelLength;
    UChar oredChars=0;
    // If we enforce STD3 rules, then ASCII characters other than LDH and dot are disallowed.
    UBool disallowNonLDHDot=(options&UIDNA_USE_STD3_RULES)!=0;
    do {
        UChar c=*s;
        if(c<=0x7f) {
            if(c==0x2e) {
                info.labelErrors|=UIDNA_ERROR_LABEL_HAS_DOT;
                *s=0xfffd;
            } else if(disallowNonLDHDot && asciiData[c]<0) {
                info.labelErrors|=UIDNA_ERROR_DISALLOWED;
                *s=0xfffd;
            }
        } else {
            oredChars|=c;
            if(disallowNonLDHDot && isNonASCIIDisallowedSTD3Valid(c)) {
                info.labelErrors|=UIDNA_ERROR_DISALLOWED;
                *s=0xfffd;
            } else if(c==0xfffd) {
                info.labelErrors|=UIDNA_ERROR_DISALLOWED;
            }
        }
        ++s;
    } while(s<limit);
    // Check for a leading combining mark after other validity checks
    // so that we don't report UIDNA_ERROR_DISALLOWED for the U+FFFD from here.
    UChar32 c;
    int32_t cpLength=0;
    // "Unsafe" is ok because unpaired surrogates were mapped to U+FFFD.
    U16_NEXT_UNSAFE(label, cpLength, c);
    if((U_GET_GC_MASK(c)&U_GC_M_MASK)!=0) {
        info.labelErrors|=UIDNA_ERROR_LEADING_COMBINING_MARK;
        labelString->replace(labelStart, cpLength, (UChar)0xfffd);
        label=labelString->getBuffer()+labelStart;
        labelLength+=1-cpLength;
        if(labelString==&dest) {
            destLabelLength=labelLength;
        }
    }
    if((info.labelErrors&severeErrors)==0) {
        // Do contextual checks only if we do not have U+FFFD from a severe error
        // because U+FFFD can make these checks fail.
        if((options&UIDNA_CHECK_BIDI)!=0 && (!info.isBiDi || info.isOkBiDi)) {
            checkLabelBiDi(label, labelLength, info);
        }
        if( (options&UIDNA_CHECK_CONTEXTJ)!=0 && (oredChars&0x200c)==0x200c &&
            !isLabelOkContextJ(label, labelLength)
        ) {
            info.labelErrors|=UIDNA_ERROR_CONTEXTJ;
        }
        if((options&UIDNA_CHECK_CONTEXTO)!=0 && oredChars>=0xb7) {
            checkLabelContextO(label, labelLength, info);
        }
        if(toASCII) {
            if(wasPunycode) {
                // Leave a Punycode label unchanged if it has no severe errors.
                if(destLabelLength>63) {
                    info.labelErrors|=UIDNA_ERROR_LABEL_TOO_LONG;
                }
                return destLabelLength;
            } else if(oredChars>=0x80) {
                // Contains non-ASCII characters.
                UnicodeString punycode;
                UChar *buffer=punycode.getBuffer(63);  // 63==maximum DNS label length
                if(buffer==NULL) {
                    errorCode=U_MEMORY_ALLOCATION_ERROR;
                    return destLabelLength;
                }
                buffer[0]=0x78;  // Write "xn--".
                buffer[1]=0x6e;
                buffer[2]=0x2d;
                buffer[3]=0x2d;
                int32_t punycodeLength=u_strToPunycode(label, labelLength,
                                                      buffer+4, punycode.getCapacity()-4,
                                                      NULL, &errorCode);
                if(errorCode==U_BUFFER_OVERFLOW_ERROR) {
                    errorCode=U_ZERO_ERROR;
                    punycode.releaseBuffer(4);
                    buffer=punycode.getBuffer(4+punycodeLength);
                    if(buffer==NULL) {
                        errorCode=U_MEMORY_ALLOCATION_ERROR;
                        return destLabelLength;
                    }
                    punycodeLength=u_strToPunycode(label, labelLength,
                                                  buffer+4, punycode.getCapacity()-4,
                                                  NULL, &errorCode);
                }
                punycodeLength+=4;
                punycode.releaseBuffer(punycodeLength);
                if(U_FAILURE(errorCode)) {
                    return destLabelLength;
                }
                if(punycodeLength>63) {
                    info.labelErrors|=UIDNA_ERROR_LABEL_TOO_LONG;
                }
                return replaceLabel(dest, destLabelStart, destLabelLength,
                                    punycode, punycodeLength, errorCode);
            } else {
                // all-ASCII label
                if(labelLength>63) {
                    info.labelErrors|=UIDNA_ERROR_LABEL_TOO_LONG;
                }
            }
        }
    } else {
        // If a Punycode label has severe errors,
        // then leave it but make sure it does not look valid.
        if(wasPunycode) {
            info.labelErrors|=UIDNA_ERROR_INVALID_ACE_LABEL;
            return markBadACELabel(dest, destLabelStart, destLabelLength, toASCII, info, errorCode);
        }
    }
    return replaceLabel(dest, destLabelStart, destLabelLength,
                        *labelString, labelLength, errorCode);
}

// Make sure an ACE label does not look valid.
// Append U+FFFD if the label has only LDH characters.
// If UIDNA_USE_STD3_RULES, also replace disallowed ASCII characters with U+FFFD.
int32_t
UTS46::markBadACELabel(UnicodeString &dest,
                       int32_t labelStart, int32_t labelLength,
                       UBool toASCII, IDNAInfo &info, UErrorCode &errorCode) const {
    if(U_FAILURE(errorCode)) {
        return 0;
    }
    UBool disallowNonLDHDot=(options&UIDNA_USE_STD3_RULES)!=0;
    UBool isASCII=TRUE;
    UBool onlyLDH=TRUE;
    const UChar *label=dest.getBuffer()+labelStart;
    // Ok to cast away const because we own the UnicodeString.
    UChar *s=(UChar *)label+4;  // After the initial "xn--".
    const UChar *limit=label+labelLength;
    do {
        UChar c=*s;
        if(c<=0x7f) {
            if(c==0x2e) {
                info.labelErrors|=UIDNA_ERROR_LABEL_HAS_DOT;
                *s=0xfffd;
                isASCII=onlyLDH=FALSE;
            } else if(asciiData[c]<0) {
                onlyLDH=FALSE;
                if(disallowNonLDHDot) {
                    *s=0xfffd;
                    isASCII=FALSE;
                }
            }
        } else {
            isASCII=onlyLDH=FALSE;
        }
    } while(++s<limit);
    if(onlyLDH) {
        dest.insert(labelStart+labelLength, (UChar)0xfffd);
        if(dest.isBogus()) {
            errorCode=U_MEMORY_ALLOCATION_ERROR;
            return 0;
        }
        ++labelLength;
    } else {
        if(toASCII && isASCII && labelLength>63) {
            info.labelErrors|=UIDNA_ERROR_LABEL_TOO_LONG;
        }
    }
    return labelLength;
}

const uint32_t L_MASK=U_MASK(U_LEFT_TO_RIGHT);
const uint32_t R_AL_MASK=U_MASK(U_RIGHT_TO_LEFT)|U_MASK(U_RIGHT_TO_LEFT_ARABIC);
const uint32_t L_R_AL_MASK=L_MASK|R_AL_MASK;

const uint32_t R_AL_AN_MASK=R_AL_MASK|U_MASK(U_ARABIC_NUMBER);

const uint32_t EN_AN_MASK=U_MASK(U_EUROPEAN_NUMBER)|U_MASK(U_ARABIC_NUMBER);
const uint32_t R_AL_EN_AN_MASK=R_AL_MASK|EN_AN_MASK;
const uint32_t L_EN_MASK=L_MASK|U_MASK(U_EUROPEAN_NUMBER);

const uint32_t ES_CS_ET_ON_BN_NSM_MASK=
    U_MASK(U_EUROPEAN_NUMBER_SEPARATOR)|
    U_MASK(U_COMMON_NUMBER_SEPARATOR)|
    U_MASK(U_EUROPEAN_NUMBER_TERMINATOR)|
    U_MASK(U_OTHER_NEUTRAL)|
    U_MASK(U_BOUNDARY_NEUTRAL)|
    U_MASK(U_DIR_NON_SPACING_MARK);
const uint32_t L_EN_ES_CS_ET_ON_BN_NSM_MASK=L_EN_MASK|ES_CS_ET_ON_BN_NSM_MASK;
const uint32_t R_AL_AN_EN_ES_CS_ET_ON_BN_NSM_MASK=R_AL_MASK|EN_AN_MASK|ES_CS_ET_ON_BN_NSM_MASK;

// We scan the whole label and check both for whether it contains RTL characters
// and whether it passes the BiDi Rule.
// In a BiDi domain name, all labels must pass the BiDi Rule, but we might find
// that a domain name is a BiDi domain name (has an RTL label) only after
// processing several earlier labels.
void
UTS46::checkLabelBiDi(const UChar *label, int32_t labelLength, IDNAInfo &info) const {
    // IDNA2008 BiDi rule
    // Get the directionality of the first character.
    UChar32 c;
    int32_t i=0;
    U16_NEXT_UNSAFE(label, i, c);
    uint32_t firstMask=U_MASK(u_charDirection(c));
    // 1. The first character must be a character with BIDI property L, R
    // or AL.  If it has the R or AL property, it is an RTL label; if it
    // has the L property, it is an LTR label.
    if((firstMask&~L_R_AL_MASK)!=0) {
        info.isOkBiDi=FALSE;
    }
    // Get the directionality of the last non-NSM character.
    uint32_t lastMask;
    for(;;) {
        if(i>=labelLength) {
            lastMask=firstMask;
            break;
        }
        U16_PREV_UNSAFE(label, labelLength, c);
        UCharDirection dir=u_charDirection(c);
        if(dir!=U_DIR_NON_SPACING_MARK) {
            lastMask=U_MASK(dir);
            break;
        }
    }
    // 3. In an RTL label, the end of the label must be a character with
    // BIDI property R, AL, EN or AN, followed by zero or more
    // characters with BIDI property NSM.
    // 6. In an LTR label, the end of the label must be a character with
    // BIDI property L or EN, followed by zero or more characters with
    // BIDI property NSM.
    if( (firstMask&L_MASK)!=0 ?
            (lastMask&~L_EN_MASK)!=0 :
            (lastMask&~R_AL_EN_AN_MASK)!=0
    ) {
        info.isOkBiDi=FALSE;
    }
    // Add the directionalities of the intervening characters.
    uint32_t mask=firstMask|lastMask;
    while(i<labelLength) {
        U16_NEXT_UNSAFE(label, i, c);
        mask|=U_MASK(u_charDirection(c));
    }
    if(firstMask&L_MASK) {
        // 5. In an LTR label, only characters with the BIDI properties L, EN,
        // ES, CS, ET, ON, BN and NSM are allowed.
        if((mask&~L_EN_ES_CS_ET_ON_BN_NSM_MASK)!=0) {
            info.isOkBiDi=FALSE;
        }
    } else {
        // 2. In an RTL label, only characters with the BIDI properties R, AL,
        // AN, EN, ES, CS, ET, ON, BN and NSM are allowed.
        if((mask&~R_AL_AN_EN_ES_CS_ET_ON_BN_NSM_MASK)!=0) {
            info.isOkBiDi=FALSE;
        }
        // 4. In an RTL label, if an EN is present, no AN may be present, and
        // vice versa.
        if((mask&EN_AN_MASK)==EN_AN_MASK) {
            info.isOkBiDi=FALSE;
        }
    }
    // An RTL label is a label that contains at least one character of type
    // R, AL or AN. [...]
    // A "BIDI domain name" is a domain name that contains at least one RTL
    // label. [...]
    // The following rule, consisting of six conditions, applies to labels
    // in BIDI domain names.
    if((mask&R_AL_AN_MASK)!=0) {
        info.isBiDi=TRUE;
    }
}

// Special code for the ASCII prefix of a BiDi domain name.
// The ASCII prefix is all-LTR.

// IDNA2008 BiDi rule, parts relevant to ASCII labels:
// 1. The first character must be a character with BIDI property L [...]
// 5. In an LTR label, only characters with the BIDI properties L, EN,
// ES, CS, ET, ON, BN and NSM are allowed.
// 6. In an LTR label, the end of the label must be a character with
// BIDI property L or EN [...]

// UTF-16 version, called for mapped ASCII prefix.
// Cannot contain uppercase A-Z.
// s[length-1] must be the trailing dot.
static UBool
isASCIIOkBiDi(const UChar *s, int32_t length) {
    int32_t labelStart=0;
    for(int32_t i=0; i<length; ++i) {
        UChar c=s[i];
        if(c==0x2e) {  // dot
            if(i>labelStart) {
                c=s[i-1];
                if(!(0x61<=c && c<=0x7a) && !(0x30<=c && c<=0x39)) {
                    // Last character in the label is not an L or EN.
                    return FALSE;
                }
            }
            labelStart=i+1;
        } else if(i==labelStart) {
            if(!(0x61<=c && c<=0x7a)) {
                // First character in the label is not an L.
                return FALSE;
            }
        } else {
            if(c<=0x20 && (c>=0x1c || (9<=c && c<=0xd))) {
                // Intermediate character in the label is a B, S or WS.
                return FALSE;
            }
        }
    }
    return TRUE;
}

// UTF-8 version, called for source ASCII prefix.
// Can contain uppercase A-Z.
// s[length-1] must be the trailing dot.
static UBool
isASCIIOkBiDi(const char *s, int32_t length) {
    int32_t labelStart=0;
    for(int32_t i=0; i<length; ++i) {
        char c=s[i];
        if(c==0x2e) {  // dot
            if(i>labelStart) {
                c=s[i-1];
                if(!(0x61<=c && c<=0x7a) && !(0x41<=c && c<=0x5a) && !(0x30<=c && c<=0x39)) {
                    // Last character in the label is not an L or EN.
                    return FALSE;
                }
            }
            labelStart=i+1;
        } else if(i==labelStart) {
            if(!(0x61<=c && c<=0x7a) && !(0x41<=c && c<=0x5a)) {
                // First character in the label is not an L.
                return FALSE;
            }
        } else {
            if(c<=0x20 && (c>=0x1c || (9<=c && c<=0xd))) {
                // Intermediate character in the label is a B, S or WS.
                return FALSE;
            }
        }
    }
    return TRUE;
}

UBool
UTS46::isLabelOkContextJ(const UChar *label, int32_t labelLength) const {
    // [IDNA2008-Tables]
    // 200C..200D  ; CONTEXTJ    # ZERO WIDTH NON-JOINER..ZERO WIDTH JOINER
    for(int32_t i=0; i<labelLength; ++i) {
        if(label[i]==0x200c) {
            // Appendix A.1. ZERO WIDTH NON-JOINER
            // Rule Set:
            //  False;
            //  If Canonical_Combining_Class(Before(cp)) .eq.  Virama Then True;
            //  If RegExpMatch((Joining_Type:{L,D})(Joining_Type:T)*\u200C
            //     (Joining_Type:T)*(Joining_Type:{R,D})) Then True;
            if(i==0) {
                return FALSE;
            }
            UChar32 c;
            int32_t j=i;
            U16_PREV_UNSAFE(label, j, c);
            if(uts46Norm2.getCombiningClass(c)==9) {
                continue;
            }
            // check precontext (Joining_Type:{L,D})(Joining_Type:T)*
            for(;;) {
                UJoiningType type=ubidi_getJoiningType(c);
                if(type==U_JT_TRANSPARENT) {
                    if(j==0) {
                        return FALSE;
                    }
                    U16_PREV_UNSAFE(label, j, c);
                } else if(type==U_JT_LEFT_JOINING || type==U_JT_DUAL_JOINING) {
                    break;  // precontext fulfilled
                } else {
                    return FALSE;
                }
            }
            // check postcontext (Joining_Type:T)*(Joining_Type:{R,D})
            for(j=i+1;;) {
                if(j==labelLength) {
                    return FALSE;
                }
                U16_NEXT_UNSAFE(label, j, c);
                UJoiningType type=ubidi_getJoiningType(c);
                if(type==U_JT_TRANSPARENT) {
                    // just skip this character
                } else if(type==U_JT_RIGHT_JOINING || type==U_JT_DUAL_JOINING) {
                    break;  // postcontext fulfilled
                } else {
                    return FALSE;
                }
            }
        } else if(label[i]==0x200d) {
            // Appendix A.2. ZERO WIDTH JOINER (U+200D)
            // Rule Set:
            //  False;
            //  If Canonical_Combining_Class(Before(cp)) .eq.  Virama Then True;
            if(i==0) {
                return FALSE;
            }
            UChar32 c;
            int32_t j=i;
            U16_PREV_UNSAFE(label, j, c);
            if(uts46Norm2.getCombiningClass(c)!=9) {
                return FALSE;
            }
        }
    }
    return TRUE;
}

void
UTS46::checkLabelContextO(const UChar *label, int32_t labelLength, IDNAInfo &info) const {
    int32_t labelEnd=labelLength-1;  // inclusive
    int32_t arabicDigits=0;  // -1 for 066x, +1 for 06Fx
    for(int32_t i=0; i<=labelEnd; ++i) {
        UChar32 c=label[i];
        if(c<0xb7) {
            // ASCII fastpath
        } else if(c<=0x6f9) {
            if(c==0xb7) {
                // Appendix A.3. MIDDLE DOT (U+00B7)
                // Rule Set:
                //  False;
                //  If Before(cp) .eq.  U+006C And
                //     After(cp) .eq.  U+006C Then True;
                if(!(0<i && label[i-1]==0x6c &&
                     i<labelEnd && label[i+1]==0x6c)) {
                    info.labelErrors|=UIDNA_ERROR_CONTEXTO_PUNCTUATION;
                }
            } else if(c==0x375) {
                // Appendix A.4. GREEK LOWER NUMERAL SIGN (KERAIA) (U+0375)
                // Rule Set:
                //  False;
                //  If Script(After(cp)) .eq.  Greek Then True;
                UScriptCode script=USCRIPT_INVALID_CODE;
                if(i<labelEnd) {
                    UErrorCode errorCode=U_ZERO_ERROR;
                    int32_t j=i+1;
                    U16_NEXT(label, j, labelLength, c);
                    script=uscript_getScript(c, &errorCode);
                }
                if(script!=USCRIPT_GREEK) {
                    info.labelErrors|=UIDNA_ERROR_CONTEXTO_PUNCTUATION;
                }
            } else if(c==0x5f3 || c==0x5f4) {
                // Appendix A.5. HEBREW PUNCTUATION GERESH (U+05F3)
                // Rule Set:
                //  False;
                //  If Script(Before(cp)) .eq.  Hebrew Then True;
                //
                // Appendix A.6. HEBREW PUNCTUATION GERSHAYIM (U+05F4)
                // Rule Set:
                //  False;
                //  If Script(Before(cp)) .eq.  Hebrew Then True;
                UScriptCode script=USCRIPT_INVALID_CODE;
                if(0<i) {
                    UErrorCode errorCode=U_ZERO_ERROR;
                    int32_t j=i;
                    U16_PREV(label, 0, j, c);
                    script=uscript_getScript(c, &errorCode);
                }
                if(script!=USCRIPT_HEBREW) {
                    info.labelErrors|=UIDNA_ERROR_CONTEXTO_PUNCTUATION;
                }
            } else if(0x660<=c /* && c<=0x6f9 */) {
                // Appendix A.8. ARABIC-INDIC DIGITS (0660..0669)
                // Rule Set:
                //  True;
                //  For All Characters:
                //    If cp .in. 06F0..06F9 Then False;
                //  End For;
                //
                // Appendix A.9. EXTENDED ARABIC-INDIC DIGITS (06F0..06F9)
                // Rule Set:
                //  True;
                //  For All Characters:
                //    If cp .in. 0660..0669 Then False;
                //  End For;
                if(c<=0x669) {
                    if(arabicDigits>0) {
                        info.labelErrors|=UIDNA_ERROR_CONTEXTO_DIGITS;
                    }
                    arabicDigits=-1;
                } else if(0x6f0<=c) {
                    if(arabicDigits<0) {
                        info.labelErrors|=UIDNA_ERROR_CONTEXTO_DIGITS;
                    }
                    arabicDigits=1;
                }
            }
        } else if(c==0x30fb) {
            // Appendix A.7. KATAKANA MIDDLE DOT (U+30FB)
            // Rule Set:
            //  False;
            //  For All Characters:
            //    If Script(cp) .in. {Hiragana, Katakana, Han} Then True;
            //  End For;
            UErrorCode errorCode=U_ZERO_ERROR;
            for(int j=0;;) {
                if(j>labelEnd) {
                    info.labelErrors|=UIDNA_ERROR_CONTEXTO_PUNCTUATION;
                    break;
                }
                U16_NEXT(label, j, labelLength, c);
                UScriptCode script=uscript_getScript(c, &errorCode);
                if(script==USCRIPT_HIRAGANA || script==USCRIPT_KATAKANA || script==USCRIPT_HAN) {
                    break;
                }
            }
        }
    }
}

U_NAMESPACE_END

// C API ------------------------------------------------------------------- ***

U_NAMESPACE_USE

U_CAPI UIDNA * U_EXPORT2
uidna_openUTS46(uint32_t options, UErrorCode *pErrorCode) {
    return reinterpret_cast<UIDNA *>(IDNA::createUTS46Instance(options, *pErrorCode));
}

U_CAPI void U_EXPORT2
uidna_close(UIDNA *idna) {
    delete reinterpret_cast<IDNA *>(idna);
}

static UBool
checkArgs(const void *label, int32_t length,
          void *dest, int32_t capacity,
          UIDNAInfo *pInfo, UErrorCode *pErrorCode) {
    if(U_FAILURE(*pErrorCode)) {
        return FALSE;
    }
    // sizeof(UIDNAInfo)=16 in the first API version.
    if(pInfo==NULL || pInfo->size<16) {
        *pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
        return FALSE;
    }
    if( (label==NULL ? length!=0 : length<-1) ||
        (dest==NULL ? capacity!=0 : capacity<0) ||
        (dest==label && label!=NULL)
    ) {
        *pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
        return FALSE;
    }
    // Set all *pInfo bytes to 0 except for the size field itself.
    uprv_memset(&pInfo->size+1, 0, pInfo->size-sizeof(pInfo->size));
    return TRUE;
}

static void
idnaInfoToStruct(IDNAInfo &info, UIDNAInfo *pInfo) {
    pInfo->isTransitionalDifferent=info.isTransitionalDifferent();
    pInfo->errors=info.getErrors();
}

U_CAPI int32_t U_EXPORT2
uidna_labelToASCII(const UIDNA *idna,
                   const UChar *label, int32_t length,
                   UChar *dest, int32_t capacity,
                   UIDNAInfo *pInfo, UErrorCode *pErrorCode) {
    if(!checkArgs(label, length, dest, capacity, pInfo, pErrorCode)) {
        return 0;
    }
    UnicodeString src((UBool)(length<0), label, length);
    UnicodeString destString(dest, 0, capacity);
    IDNAInfo info;
    reinterpret_cast<const IDNA *>(idna)->labelToASCII(src, destString, info, *pErrorCode);
    idnaInfoToStruct(info, pInfo);
    return destString.extract(dest, capacity, *pErrorCode);
}

U_CAPI int32_t U_EXPORT2
uidna_labelToUnicode(const UIDNA *idna,
                     const UChar *label, int32_t length,
                     UChar *dest, int32_t capacity,
                     UIDNAInfo *pInfo, UErrorCode *pErrorCode) {
    if(!checkArgs(label, length, dest, capacity, pInfo, pErrorCode)) {
        return 0;
    }
    UnicodeString src((UBool)(length<0), label, length);
    UnicodeString destString(dest, 0, capacity);
    IDNAInfo info;
    reinterpret_cast<const IDNA *>(idna)->labelToUnicode(src, destString, info, *pErrorCode);
    idnaInfoToStruct(info, pInfo);
    return destString.extract(dest, capacity, *pErrorCode);
}

U_CAPI int32_t U_EXPORT2
uidna_nameToASCII(const UIDNA *idna,
                  const UChar *name, int32_t length,
                  UChar *dest, int32_t capacity,
                  UIDNAInfo *pInfo, UErrorCode *pErrorCode) {
    if(!checkArgs(name, length, dest, capacity, pInfo, pErrorCode)) {
        return 0;
    }
    UnicodeString src((UBool)(length<0), name, length);
    UnicodeString destString(dest, 0, capacity);
    IDNAInfo info;
    reinterpret_cast<const IDNA *>(idna)->nameToASCII(src, destString, info, *pErrorCode);
    idnaInfoToStruct(info, pInfo);
    return destString.extract(dest, capacity, *pErrorCode);
}

U_CAPI int32_t U_EXPORT2
uidna_nameToUnicode(const UIDNA *idna,
                    const UChar *name, int32_t length,
                    UChar *dest, int32_t capacity,
                    UIDNAInfo *pInfo, UErrorCode *pErrorCode) {
    if(!checkArgs(name, length, dest, capacity, pInfo, pErrorCode)) {
        return 0;
    }
    UnicodeString src((UBool)(length<0), name, length);
    UnicodeString destString(dest, 0, capacity);
    IDNAInfo info;
    reinterpret_cast<const IDNA *>(idna)->nameToUnicode(src, destString, info, *pErrorCode);
    idnaInfoToStruct(info, pInfo);
    return destString.extract(dest, capacity, *pErrorCode);
}

U_CAPI int32_t U_EXPORT2
uidna_labelToASCII_UTF8(const UIDNA *idna,
                        const char *label, int32_t length,
                        char *dest, int32_t capacity,
                        UIDNAInfo *pInfo, UErrorCode *pErrorCode) {
    if(!checkArgs(label, length, dest, capacity, pInfo, pErrorCode)) {
        return 0;
    }
    StringPiece src(label, length<0 ? static_cast<int32_t>(uprv_strlen(label)) : length);
    CheckedArrayByteSink sink(dest, capacity);
    IDNAInfo info;
    reinterpret_cast<const IDNA *>(idna)->labelToASCII_UTF8(src, sink, info, *pErrorCode);
    idnaInfoToStruct(info, pInfo);
    return u_terminateChars(dest, capacity, sink.NumberOfBytesAppended(), pErrorCode);
}

U_CAPI int32_t U_EXPORT2
uidna_labelToUnicodeUTF8(const UIDNA *idna,
                         const char *label, int32_t length,
                         char *dest, int32_t capacity,
                         UIDNAInfo *pInfo, UErrorCode *pErrorCode) {
    if(!checkArgs(label, length, dest, capacity, pInfo, pErrorCode)) {
        return 0;
    }
    StringPiece src(label, length<0 ? static_cast<int32_t>(uprv_strlen(label)) : length);
    CheckedArrayByteSink sink(dest, capacity);
    IDNAInfo info;
    reinterpret_cast<const IDNA *>(idna)->labelToUnicodeUTF8(src, sink, info, *pErrorCode);
    idnaInfoToStruct(info, pInfo);
    return u_terminateChars(dest, capacity, sink.NumberOfBytesAppended(), pErrorCode);
}

U_CAPI int32_t U_EXPORT2
uidna_nameToASCII_UTF8(const UIDNA *idna,
                       const char *name, int32_t length,
                       char *dest, int32_t capacity,
                       UIDNAInfo *pInfo, UErrorCode *pErrorCode) {
    if(!checkArgs(name, length, dest, capacity, pInfo, pErrorCode)) {
        return 0;
    }
    StringPiece src(name, length<0 ? static_cast<int32_t>(uprv_strlen(name)) : length);
    CheckedArrayByteSink sink(dest, capacity);
    IDNAInfo info;
    reinterpret_cast<const IDNA *>(idna)->nameToASCII_UTF8(src, sink, info, *pErrorCode);
    idnaInfoToStruct(info, pInfo);
    return u_terminateChars(dest, capacity, sink.NumberOfBytesAppended(), pErrorCode);
}

U_CAPI int32_t U_EXPORT2
uidna_nameToUnicodeUTF8(const UIDNA *idna,
                        const char *name, int32_t length,
                        char *dest, int32_t capacity,
                        UIDNAInfo *pInfo, UErrorCode *pErrorCode) {
    if(!checkArgs(name, length, dest, capacity, pInfo, pErrorCode)) {
        return 0;
    }
    StringPiece src(name, length<0 ? static_cast<int32_t>(uprv_strlen(name)) : length);
    CheckedArrayByteSink sink(dest, capacity);
    IDNAInfo info;
    reinterpret_cast<const IDNA *>(idna)->nameToUnicodeUTF8(src, sink, info, *pErrorCode);
    idnaInfoToStruct(info, pInfo);
    return u_terminateChars(dest, capacity, sink.NumberOfBytesAppended(), pErrorCode);
}

#endif  // UCONFIG_NO_IDNA