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      1 /*
      2 *******************************************************************************
      3 *   Copyright (C) 2010, International Business Machines
      4 *   Corporation and others.  All Rights Reserved.
      5 *******************************************************************************
      6 *   file name:  uts46.cpp
      7 *   encoding:   US-ASCII
      8 *   tab size:   8 (not used)
      9 *   indentation:4
     10 *
     11 *   created on: 2010mar09
     12 *   created by: Markus W. Scherer
     13 */
     14 
     15 #include "unicode/utypes.h"
     16 
     17 #if !UCONFIG_NO_IDNA
     18 
     19 #include "unicode/idna.h"
     20 #include "unicode/normalizer2.h"
     21 #include "unicode/ustring.h"
     22 #include "cmemory.h"
     23 #include "cstring.h"
     24 #include "punycode.h"
     25 #include "ustr_imp.h"
     26 
     27 #define LENGTHOF(array) (int32_t)(sizeof(array)/sizeof((array)[0]))
     28 
     29 // Note about tests for UIDNA_ERROR_DOMAIN_NAME_TOO_LONG:
     30 //
     31 // The domain name length limit is 255 octets in an internal DNS representation
     32 // where the last ("root") label is the empty label
     33 // represented by length byte 0 alone.
     34 // In a conventional string, this translates to 253 characters, or 254
     35 // if there is a trailing dot for the root label.
     36 
     37 U_NAMESPACE_BEGIN
     38 
     39 // Severe errors which usually result in a U+FFFD replacement character in the result string.
     40 const uint32_t severeErrors=
     41     UIDNA_ERROR_LEADING_COMBINING_MARK|
     42     UIDNA_ERROR_DISALLOWED|
     43     UIDNA_ERROR_PUNYCODE|
     44     UIDNA_ERROR_LABEL_HAS_DOT|
     45     UIDNA_ERROR_INVALID_ACE_LABEL;
     46 
     47 static inline UBool
     48 isASCIIString(const UnicodeString &dest) {
     49     const UChar *s=dest.getBuffer();
     50     const UChar *limit=s+dest.length();
     51     while(s<limit) {
     52         if(*s++>0x7f) {
     53             return FALSE;
     54         }
     55     }
     56     return TRUE;
     57 }
     58 
     59 static UBool
     60 isASCIIOkBiDi(const UChar *s, int32_t length);
     61 
     62 static UBool
     63 isASCIIOkBiDi(const char *s, int32_t length);
     64 
     65 // IDNA class default implementations -------------------------------------- ***
     66 
     67 void
     68 IDNA::labelToASCII_UTF8(const StringPiece &label, ByteSink &dest,
     69                         IDNAInfo &info, UErrorCode &errorCode) const {
     70     if(U_SUCCESS(errorCode)) {
     71         UnicodeString destString;
     72         labelToASCII(UnicodeString::fromUTF8(label), destString,
     73                      info, errorCode).toUTF8(dest);
     74     }
     75 }
     76 
     77 void
     78 IDNA::labelToUnicodeUTF8(const StringPiece &label, ByteSink &dest,
     79                          IDNAInfo &info, UErrorCode &errorCode) const {
     80     if(U_SUCCESS(errorCode)) {
     81         UnicodeString destString;
     82         labelToUnicode(UnicodeString::fromUTF8(label), destString,
     83                        info, errorCode).toUTF8(dest);
     84     }
     85 }
     86 
     87 void
     88 IDNA::nameToASCII_UTF8(const StringPiece &name, ByteSink &dest,
     89                        IDNAInfo &info, UErrorCode &errorCode) const {
     90     if(U_SUCCESS(errorCode)) {
     91         UnicodeString destString;
     92         nameToASCII(UnicodeString::fromUTF8(name), destString,
     93                     info, errorCode).toUTF8(dest);
     94     }
     95 }
     96 
     97 void
     98 IDNA::nameToUnicodeUTF8(const StringPiece &name, ByteSink &dest,
     99                         IDNAInfo &info, UErrorCode &errorCode) const {
    100     if(U_SUCCESS(errorCode)) {
    101         UnicodeString destString;
    102         nameToUnicode(UnicodeString::fromUTF8(name), destString,
    103                       info, errorCode).toUTF8(dest);
    104     }
    105 }
    106 
    107 UOBJECT_DEFINE_NO_RTTI_IMPLEMENTATION(IDNA)
    108 
    109 // UTS46 class declaration ------------------------------------------------- ***
    110 
    111 class UTS46 : public IDNA {
    112 public:
    113     UTS46(uint32_t options, UErrorCode &errorCode);
    114     virtual ~UTS46();
    115 
    116     virtual UnicodeString &
    117     labelToASCII(const UnicodeString &label, UnicodeString &dest,
    118                  IDNAInfo &info, UErrorCode &errorCode) const;
    119 
    120     virtual UnicodeString &
    121     labelToUnicode(const UnicodeString &label, UnicodeString &dest,
    122                    IDNAInfo &info, UErrorCode &errorCode) const;
    123 
    124     virtual UnicodeString &
    125     nameToASCII(const UnicodeString &name, UnicodeString &dest,
    126                 IDNAInfo &info, UErrorCode &errorCode) const;
    127 
    128     virtual UnicodeString &
    129     nameToUnicode(const UnicodeString &name, UnicodeString &dest,
    130                   IDNAInfo &info, UErrorCode &errorCode) const;
    131 
    132     virtual void
    133     labelToASCII_UTF8(const StringPiece &label, ByteSink &dest,
    134                       IDNAInfo &info, UErrorCode &errorCode) const;
    135 
    136     virtual void
    137     labelToUnicodeUTF8(const StringPiece &label, ByteSink &dest,
    138                        IDNAInfo &info, UErrorCode &errorCode) const;
    139 
    140     virtual void
    141     nameToASCII_UTF8(const StringPiece &name, ByteSink &dest,
    142                      IDNAInfo &info, UErrorCode &errorCode) const;
    143 
    144     virtual void
    145     nameToUnicodeUTF8(const StringPiece &name, ByteSink &dest,
    146                       IDNAInfo &info, UErrorCode &errorCode) const;
    147 
    148 private:
    149     UnicodeString &
    150     process(const UnicodeString &src,
    151             UBool isLabel, UBool toASCII,
    152             UnicodeString &dest,
    153             IDNAInfo &info, UErrorCode &errorCode) const;
    154 
    155     void
    156     processUTF8(const StringPiece &src,
    157                 UBool isLabel, UBool toASCII,
    158                 ByteSink &dest,
    159                 IDNAInfo &info, UErrorCode &errorCode) const;
    160 
    161     UnicodeString &
    162     processUnicode(const UnicodeString &src,
    163                    int32_t labelStart, int32_t mappingStart,
    164                    UBool isLabel, UBool toASCII,
    165                    UnicodeString &dest,
    166                    IDNAInfo &info, UErrorCode &errorCode) const;
    167 
    168     // returns the new dest.length()
    169     int32_t
    170     mapDevChars(UnicodeString &dest, int32_t labelStart, int32_t mappingStart,
    171                 UErrorCode &errorCode) const;
    172 
    173     // returns the new label length
    174     int32_t
    175     processLabel(UnicodeString &dest,
    176                  int32_t labelStart, int32_t labelLength,
    177                  UBool toASCII,
    178                  IDNAInfo &info, UErrorCode &errorCode) const;
    179     int32_t
    180     markBadACELabel(UnicodeString &dest,
    181                     int32_t labelStart, int32_t labelLength,
    182                     UBool toASCII, IDNAInfo &info) const;
    183 
    184     void
    185     checkLabelBiDi(const UChar *label, int32_t labelLength, IDNAInfo &info) const;
    186 
    187     UBool
    188     isLabelOkContextJ(const UChar *label, int32_t labelLength) const;
    189 
    190     const Normalizer2 &uts46Norm2;  // uts46.nrm
    191     uint32_t options;
    192 };
    193 
    194 IDNA *
    195 IDNA::createUTS46Instance(uint32_t options, UErrorCode &errorCode) {
    196     if(U_SUCCESS(errorCode)) {
    197         IDNA *idna=new UTS46(options, errorCode);
    198         if(idna==NULL) {
    199             errorCode=U_MEMORY_ALLOCATION_ERROR;
    200         } else if(U_FAILURE(errorCode)) {
    201             delete idna;
    202             idna=NULL;
    203         }
    204         return idna;
    205     } else {
    206         return NULL;
    207     }
    208 }
    209 
    210 // UTS46 implementation ---------------------------------------------------- ***
    211 
    212 UTS46::UTS46(uint32_t opt, UErrorCode &errorCode)
    213         : uts46Norm2(*Normalizer2::getInstance(NULL, "uts46", UNORM2_COMPOSE, errorCode)),
    214           options(opt) {}
    215 
    216 UTS46::~UTS46() {}
    217 
    218 UnicodeString &
    219 UTS46::labelToASCII(const UnicodeString &label, UnicodeString &dest,
    220                     IDNAInfo &info, UErrorCode &errorCode) const {
    221     return process(label, TRUE, TRUE, dest, info, errorCode);
    222 }
    223 
    224 UnicodeString &
    225 UTS46::labelToUnicode(const UnicodeString &label, UnicodeString &dest,
    226                       IDNAInfo &info, UErrorCode &errorCode) const {
    227     return process(label, TRUE, FALSE, dest, info, errorCode);
    228 }
    229 
    230 UnicodeString &
    231 UTS46::nameToASCII(const UnicodeString &name, UnicodeString &dest,
    232                    IDNAInfo &info, UErrorCode &errorCode) const {
    233     process(name, FALSE, TRUE, dest, info, errorCode);
    234     if( dest.length()>=254 && (info.errors&UIDNA_ERROR_DOMAIN_NAME_TOO_LONG)==0 &&
    235         isASCIIString(dest) &&
    236         (dest.length()>254 || dest[253]!=0x2e)
    237     ) {
    238         info.errors|=UIDNA_ERROR_DOMAIN_NAME_TOO_LONG;
    239     }
    240     return dest;
    241 }
    242 
    243 UnicodeString &
    244 UTS46::nameToUnicode(const UnicodeString &name, UnicodeString &dest,
    245                      IDNAInfo &info, UErrorCode &errorCode) const {
    246     return process(name, FALSE, FALSE, dest, info, errorCode);
    247 }
    248 
    249 void
    250 UTS46::labelToASCII_UTF8(const StringPiece &label, ByteSink &dest,
    251                          IDNAInfo &info, UErrorCode &errorCode) const {
    252     processUTF8(label, TRUE, TRUE, dest, info, errorCode);
    253 }
    254 
    255 void
    256 UTS46::labelToUnicodeUTF8(const StringPiece &label, ByteSink &dest,
    257                           IDNAInfo &info, UErrorCode &errorCode) const {
    258     processUTF8(label, TRUE, FALSE, dest, info, errorCode);
    259 }
    260 
    261 void
    262 UTS46::nameToASCII_UTF8(const StringPiece &name, ByteSink &dest,
    263                         IDNAInfo &info, UErrorCode &errorCode) const {
    264     processUTF8(name, FALSE, TRUE, dest, info, errorCode);
    265 }
    266 
    267 void
    268 UTS46::nameToUnicodeUTF8(const StringPiece &name, ByteSink &dest,
    269                          IDNAInfo &info, UErrorCode &errorCode) const {
    270     processUTF8(name, FALSE, FALSE, dest, info, errorCode);
    271 }
    272 
    273 // UTS #46 data for ASCII characters.
    274 // The normalizer (using uts46.nrm) maps uppercase ASCII letters to lowercase
    275 // and passes through all other ASCII characters.
    276 // If UIDNA_USE_STD3_RULES is set, then non-LDH characters are disallowed
    277 // using this data.
    278 // The ASCII fastpath also uses this data.
    279 // Values: -1=disallowed  0==valid  1==mapped (lowercase)
    280 static const int8_t asciiData[128]={
    281     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    282     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
    283     // 002D..002E; valid  #  HYPHEN-MINUS..FULL STOP
    284     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  0,  0, -1,
    285     // 0030..0039; valid  #  DIGIT ZERO..DIGIT NINE
    286      0,  0,  0,  0,  0,  0,  0,  0,  0,  0, -1, -1, -1, -1, -1, -1,
    287     // 0041..005A; mapped  #  LATIN CAPITAL LETTER A..LATIN CAPITAL LETTER Z
    288     -1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
    289      1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1, -1, -1, -1, -1, -1,
    290     // 0061..007A; valid  #  LATIN SMALL LETTER A..LATIN SMALL LETTER Z
    291     -1,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
    292      0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0, -1, -1, -1, -1, -1
    293 };
    294 
    295 UnicodeString &
    296 UTS46::process(const UnicodeString &src,
    297                UBool isLabel, UBool toASCII,
    298                UnicodeString &dest,
    299                IDNAInfo &info, UErrorCode &errorCode) const {
    300     // uts46Norm2.normalize() would do all of this error checking and setup,
    301     // but with the ASCII fastpath we do not always call it, and do not
    302     // call it first.
    303     if(U_FAILURE(errorCode)) {
    304         dest.setToBogus();
    305         return dest;
    306     }
    307     const UChar *srcArray=src.getBuffer();
    308     if(&dest==&src || srcArray==NULL) {
    309         errorCode=U_ILLEGAL_ARGUMENT_ERROR;
    310         dest.setToBogus();
    311         return dest;
    312     }
    313     // Arguments are fine, reset output values.
    314     dest.remove();
    315     info.reset();
    316     int32_t srcLength=src.length();
    317     if(srcLength==0) {
    318         if(toASCII) {
    319             info.errors|=UIDNA_ERROR_EMPTY_LABEL;
    320         }
    321         return dest;
    322     }
    323     UChar *destArray=dest.getBuffer(srcLength);
    324     if(destArray==NULL) {
    325         errorCode=U_MEMORY_ALLOCATION_ERROR;
    326         return dest;
    327     }
    328     // ASCII fastpath
    329     UBool disallowNonLDHDot=(options&UIDNA_USE_STD3_RULES)!=0;
    330     int32_t labelStart=0;
    331     int32_t i;
    332     for(i=0;; ++i) {
    333         if(i==srcLength) {
    334             if(toASCII) {
    335                 if((i-labelStart)>63) {
    336                     info.labelErrors|=UIDNA_ERROR_LABEL_TOO_LONG;
    337                 }
    338                 // There is a trailing dot if labelStart==i.
    339                 if(!isLabel && i>=254 && (i>254 || labelStart<i)) {
    340                     info.errors|=UIDNA_ERROR_DOMAIN_NAME_TOO_LONG;
    341                 }
    342             }
    343             info.errors|=info.labelErrors;
    344             dest.releaseBuffer(i);
    345             return dest;
    346         }
    347         UChar c=srcArray[i];
    348         if(c>0x7f) {
    349             break;
    350         }
    351         int cData=asciiData[c];
    352         if(cData>0) {
    353             destArray[i]=c+0x20;  // Lowercase an uppercase ASCII letter.
    354         } else if(cData<0 && disallowNonLDHDot) {
    355             break;  // Replacing with U+FFFD can be complicated for toASCII.
    356         } else {
    357             destArray[i]=c;
    358             if(c==0x2d) {  // hyphen
    359                 if(i==(labelStart+3) && srcArray[i-1]==0x2d) {
    360                     // "??--..." is Punycode or forbidden.
    361                     ++i;  // '-' was copied to dest already
    362                     break;
    363                 }
    364                 if(i==labelStart) {
    365                     // label starts with "-"
    366                     info.labelErrors|=UIDNA_ERROR_LEADING_HYPHEN;
    367                 }
    368                 if((i+1)==srcLength || srcArray[i+1]==0x2e) {
    369                     // label ends with "-"
    370                     info.labelErrors|=UIDNA_ERROR_TRAILING_HYPHEN;
    371                 }
    372             } else if(c==0x2e) {  // dot
    373                 if(isLabel) {
    374                     // Replacing with U+FFFD can be complicated for toASCII.
    375                     ++i;  // '.' was copied to dest already
    376                     break;
    377                 }
    378                 if(toASCII) {
    379                     // Permit an empty label at the end but not elsewhere.
    380                     if(i==labelStart && i<(srcLength-1)) {
    381                         info.labelErrors|=UIDNA_ERROR_EMPTY_LABEL;
    382                     } else if((i-labelStart)>63) {
    383                         info.labelErrors|=UIDNA_ERROR_LABEL_TOO_LONG;
    384                     }
    385                 }
    386                 info.errors|=info.labelErrors;
    387                 info.labelErrors=0;
    388                 labelStart=i+1;
    389             }
    390         }
    391     }
    392     info.errors|=info.labelErrors;
    393     dest.releaseBuffer(i);
    394     processUnicode(src, labelStart, i, isLabel, toASCII, dest, info, errorCode);
    395     if( info.isBiDi && U_SUCCESS(errorCode) && (info.errors&severeErrors)==0 &&
    396         (!info.isOkBiDi || (labelStart>0 && !isASCIIOkBiDi(dest.getBuffer(), labelStart)))
    397     ) {
    398         info.errors|=UIDNA_ERROR_BIDI;
    399     }
    400     return dest;
    401 }
    402 
    403 void
    404 UTS46::processUTF8(const StringPiece &src,
    405                    UBool isLabel, UBool toASCII,
    406                    ByteSink &dest,
    407                    IDNAInfo &info, UErrorCode &errorCode) const {
    408     if(U_FAILURE(errorCode)) {
    409         return;
    410     }
    411     const char *srcArray=src.data();
    412     int32_t srcLength=src.length();
    413     if(srcArray==NULL && srcLength!=0) {
    414         errorCode=U_ILLEGAL_ARGUMENT_ERROR;
    415         return;
    416     }
    417     // Arguments are fine, reset output values.
    418     info.reset();
    419     if(srcLength==0) {
    420         if(toASCII) {
    421             info.errors|=UIDNA_ERROR_EMPTY_LABEL;
    422         }
    423         dest.Flush();
    424         return;
    425     }
    426     UnicodeString destString;
    427     int32_t labelStart=0;
    428     if(srcLength<=256) {  // length of stackArray[]
    429         // ASCII fastpath
    430         char stackArray[256];
    431         int32_t destCapacity;
    432         char *destArray=dest.GetAppendBuffer(srcLength, srcLength+20,
    433                                              stackArray, LENGTHOF(stackArray), &destCapacity);
    434         UBool disallowNonLDHDot=(options&UIDNA_USE_STD3_RULES)!=0;
    435         int32_t i;
    436         for(i=0;; ++i) {
    437             if(i==srcLength) {
    438                 if(toASCII) {
    439                     if((i-labelStart)>63) {
    440                         info.labelErrors|=UIDNA_ERROR_LABEL_TOO_LONG;
    441                     }
    442                     // There is a trailing dot if labelStart==i.
    443                     if(!isLabel && i>=254 && (i>254 || labelStart<i)) {
    444                         info.errors|=UIDNA_ERROR_DOMAIN_NAME_TOO_LONG;
    445                     }
    446                 }
    447                 info.errors|=info.labelErrors;
    448                 dest.Append(destArray, i);
    449                 dest.Flush();
    450                 return;
    451             }
    452             char c=srcArray[i];
    453             if((int8_t)c<0) {  // (uint8_t)c>0x7f
    454                 break;
    455             }
    456             int cData=asciiData[(int)c];  // Cast: gcc warns about indexing with a char.
    457             if(cData>0) {
    458                 destArray[i]=c+0x20;  // Lowercase an uppercase ASCII letter.
    459             } else if(cData<0 && disallowNonLDHDot) {
    460                 break;  // Replacing with U+FFFD can be complicated for toASCII.
    461             } else {
    462                 destArray[i]=c;
    463                 if(c==0x2d) {  // hyphen
    464                     if(i==(labelStart+3) && srcArray[i-1]==0x2d) {
    465                         // "??--..." is Punycode or forbidden.
    466                         break;
    467                     }
    468                     if(i==labelStart) {
    469                         // label starts with "-"
    470                         info.labelErrors|=UIDNA_ERROR_LEADING_HYPHEN;
    471                     }
    472                     if((i+1)==srcLength || srcArray[i+1]==0x2e) {
    473                         // label ends with "-"
    474                         info.labelErrors|=UIDNA_ERROR_TRAILING_HYPHEN;
    475                     }
    476                 } else if(c==0x2e) {  // dot
    477                     if(isLabel) {
    478                         break;  // Replacing with U+FFFD can be complicated for toASCII.
    479                     }
    480                     if(toASCII) {
    481                         // Permit an empty label at the end but not elsewhere.
    482                         if(i==labelStart && i<(srcLength-1)) {
    483                             info.labelErrors|=UIDNA_ERROR_EMPTY_LABEL;
    484                         } else if((i-labelStart)>63) {
    485                             info.labelErrors|=UIDNA_ERROR_LABEL_TOO_LONG;
    486                         }
    487                     }
    488                     info.errors|=info.labelErrors;
    489                     info.labelErrors=0;
    490                     labelStart=i+1;
    491                 }
    492             }
    493         }
    494         info.errors|=info.labelErrors;
    495         // Convert the processed ASCII prefix of the current label to UTF-16.
    496         int32_t mappingStart=i-labelStart;
    497         destString=UnicodeString::fromUTF8(StringPiece(destArray+labelStart, mappingStart));
    498         // Output the previous ASCII labels and process the rest of src in UTF-16.
    499         dest.Append(destArray, labelStart);
    500         processUnicode(UnicodeString::fromUTF8(StringPiece(src, labelStart)), 0, mappingStart,
    501                        isLabel, toASCII,
    502                        destString, info, errorCode);
    503     } else {
    504         // src is too long for the ASCII fastpath implementation.
    505         processUnicode(UnicodeString::fromUTF8(src), 0, 0,
    506                        isLabel, toASCII,
    507                        destString, info, errorCode);
    508     }
    509     destString.toUTF8(dest);  // calls dest.Flush()
    510     if(toASCII && !isLabel) {
    511         // length==labelStart==254 means that there is a trailing dot (ok) and
    512         // destString is empty (do not index at 253-labelStart).
    513         int32_t length=labelStart+destString.length();
    514         if( length>=254 && isASCIIString(destString) &&
    515             (length>254 ||
    516              (labelStart<254 && destString[253-labelStart]!=0x2e))
    517         ) {
    518             info.errors|=UIDNA_ERROR_DOMAIN_NAME_TOO_LONG;
    519         }
    520     }
    521     if( info.isBiDi && U_SUCCESS(errorCode) && (info.errors&severeErrors)==0 &&
    522         (!info.isOkBiDi || (labelStart>0 && !isASCIIOkBiDi(srcArray, labelStart)))
    523     ) {
    524         info.errors|=UIDNA_ERROR_BIDI;
    525     }
    526 }
    527 
    528 UnicodeString &
    529 UTS46::processUnicode(const UnicodeString &src,
    530                       int32_t labelStart, int32_t mappingStart,
    531                       UBool isLabel, UBool toASCII,
    532                       UnicodeString &dest,
    533                       IDNAInfo &info, UErrorCode &errorCode) const {
    534     if(mappingStart==0) {
    535         uts46Norm2.normalize(src, dest, errorCode);
    536     } else {
    537         uts46Norm2.normalizeSecondAndAppend(dest, src.tempSubString(mappingStart), errorCode);
    538     }
    539     if(U_FAILURE(errorCode)) {
    540         return dest;
    541     }
    542     UBool doMapDevChars=
    543         toASCII ? (options&UIDNA_NONTRANSITIONAL_TO_ASCII)==0 :
    544                   (options&UIDNA_NONTRANSITIONAL_TO_UNICODE)==0;
    545     const UChar *destArray=dest.getBuffer();
    546     int32_t destLength=dest.length();
    547     int32_t labelLimit=labelStart;
    548     while(labelLimit<destLength) {
    549         UChar c=destArray[labelLimit];
    550         if(c==0x2e && !isLabel) {
    551             int32_t labelLength=labelLimit-labelStart;
    552             int32_t newLength=processLabel(dest, labelStart, labelLength,
    553                                             toASCII, info, errorCode);
    554             info.errors|=info.labelErrors;
    555             info.labelErrors=0;
    556             if(U_FAILURE(errorCode)) {
    557                 return dest;
    558             }
    559             destArray=dest.getBuffer();
    560             destLength+=newLength-labelLength;
    561             labelLimit=labelStart+=newLength+1;
    562         } else if(0xdf<=c && c<=0x200d && (c==0xdf || c==0x3c2 || c>=0x200c)) {
    563             info.isTransDiff=TRUE;
    564             if(doMapDevChars) {
    565                 destLength=mapDevChars(dest, labelStart, labelLimit, errorCode);
    566                 if(U_FAILURE(errorCode)) {
    567                     return dest;
    568                 }
    569                 destArray=dest.getBuffer();
    570                 // Do not increment labelLimit in case c was removed.
    571                 // All deviation characters have been mapped, no need to check for them again.
    572                 doMapDevChars=FALSE;
    573             } else {
    574                 ++labelLimit;
    575             }
    576         } else {
    577             ++labelLimit;
    578         }
    579     }
    580     // Permit an empty label at the end (0<labelStart==labelLimit==destLength is ok)
    581     // but not an empty label elsewhere nor a completely empty domain name.
    582     // processLabel() sets UIDNA_ERROR_EMPTY_LABEL when labelLength==0.
    583     if(0==labelStart || labelStart<labelLimit) {
    584         processLabel(dest, labelStart, labelLimit-labelStart,
    585                       toASCII, info, errorCode);
    586         info.errors|=info.labelErrors;
    587     }
    588     return dest;
    589 }
    590 
    591 int32_t
    592 UTS46::mapDevChars(UnicodeString &dest, int32_t labelStart, int32_t mappingStart,
    593                    UErrorCode &errorCode) const {
    594     int32_t length=dest.length();
    595     UChar *s=dest.getBuffer(dest[mappingStart]==0xdf ? length+1 : length);
    596     if(s==NULL) {
    597         errorCode=U_MEMORY_ALLOCATION_ERROR;
    598         return length;
    599     }
    600     int32_t capacity=dest.getCapacity();
    601     UBool didMapDevChars=FALSE;
    602     int32_t readIndex=mappingStart, writeIndex=mappingStart;
    603     do {
    604         UChar c=s[readIndex++];
    605         switch(c) {
    606         case 0xdf:
    607             // Map sharp s to ss.
    608             didMapDevChars=TRUE;
    609             s[writeIndex++]=0x73;  // Replace sharp s with first s.
    610             // Insert second s and account for possible buffer reallocation.
    611             if(writeIndex==readIndex) {
    612                 if(length==capacity) {
    613                     dest.releaseBuffer(length);
    614                     s=dest.getBuffer(length+1);
    615                     if(s==NULL) {
    616                         errorCode=U_MEMORY_ALLOCATION_ERROR;
    617                         return length;
    618                     }
    619                     capacity=dest.getCapacity();
    620                 }
    621                 u_memmove(s+writeIndex+1, s+writeIndex, length-writeIndex);
    622                 ++readIndex;
    623             }
    624             s[writeIndex++]=0x73;
    625             ++length;
    626             break;
    627         case 0x3c2:  // Map final sigma to nonfinal sigma.
    628             didMapDevChars=TRUE;
    629             s[writeIndex++]=0x3c3;
    630             break;
    631         case 0x200c:  // Ignore/remove ZWNJ.
    632         case 0x200d:  // Ignore/remove ZWJ.
    633             didMapDevChars=TRUE;
    634             --length;
    635             break;
    636         default:
    637             // Only really necessary if writeIndex was different from readIndex.
    638             s[writeIndex++]=c;
    639             break;
    640         }
    641     } while(writeIndex<length);
    642     dest.releaseBuffer(length);
    643     if(didMapDevChars) {
    644         // Mapping deviation characters might have resulted in an un-NFC string.
    645         // We could use either the NFC or the UTS #46 normalizer.
    646         // By using the UTS #46 normalizer again, we avoid having to load a second .nrm data file.
    647         UnicodeString normalized;
    648         uts46Norm2.normalize(dest.tempSubString(labelStart), normalized, errorCode);
    649         if(U_SUCCESS(errorCode)) {
    650             dest.replace(labelStart, 0x7fffffff, normalized);
    651             return dest.length();
    652         }
    653     }
    654     return length;
    655 }
    656 
    657 // Some non-ASCII characters are equivalent to sequences with
    658 // non-LDH ASCII characters. To find them:
    659 // grep disallowed_STD3_valid IdnaMappingTable.txt (or uts46.txt)
    660 static inline UBool
    661 isNonASCIIDisallowedSTD3Valid(UChar32 c) {
    662     return c==0x2260 || c==0x226E || c==0x226F;
    663 }
    664 
    665 // Replace the label in dest with the label string, if the label was modified.
    666 // If &label==&dest then the label was modified in-place and labelLength
    667 // is the new label length, different from label.length().
    668 // If &label!=&dest then labelLength==label.length().
    669 // Returns labelLength (= the new label length).
    670 static int32_t
    671 replaceLabel(UnicodeString &dest, int32_t destLabelStart, int32_t destLabelLength,
    672              const UnicodeString &label, int32_t labelLength) {
    673     if(&label!=&dest) {
    674         dest.replace(destLabelStart, destLabelLength, label);
    675     }
    676     return labelLength;
    677 }
    678 
    679 int32_t
    680 UTS46::processLabel(UnicodeString &dest,
    681                     int32_t labelStart, int32_t labelLength,
    682                     UBool toASCII,
    683                     IDNAInfo &info, UErrorCode &errorCode) const {
    684     UnicodeString fromPunycode;
    685     UnicodeString *labelString;
    686     const UChar *label=dest.getBuffer()+labelStart;
    687     int32_t destLabelStart=labelStart;
    688     int32_t destLabelLength=labelLength;
    689     UBool wasPunycode;
    690     if(labelLength>=4 && label[0]==0x78 && label[1]==0x6e && label[2]==0x2d && label[3]==0x2d) {
    691         // Label starts with "xn--", try to un-Punycode it.
    692         wasPunycode=TRUE;
    693         UChar *unicodeBuffer=fromPunycode.getBuffer(-1);  // capacity==-1: most labels should fit
    694         if(unicodeBuffer==NULL) {
    695             // Should never occur if we used capacity==-1 which uses the internal buffer.
    696             errorCode=U_MEMORY_ALLOCATION_ERROR;
    697             return labelLength;
    698         }
    699         UErrorCode punycodeErrorCode=U_ZERO_ERROR;
    700         int32_t unicodeLength=u_strFromPunycode(label+4, labelLength-4,
    701                                                 unicodeBuffer, fromPunycode.getCapacity(),
    702                                                 NULL, &punycodeErrorCode);
    703         if(punycodeErrorCode==U_BUFFER_OVERFLOW_ERROR) {
    704             fromPunycode.releaseBuffer(0);
    705             unicodeBuffer=fromPunycode.getBuffer(unicodeLength);
    706             if(unicodeBuffer==NULL) {
    707                 errorCode=U_MEMORY_ALLOCATION_ERROR;
    708                 return labelLength;
    709             }
    710             punycodeErrorCode=U_ZERO_ERROR;
    711             unicodeLength=u_strFromPunycode(label+4, labelLength-4,
    712                                             unicodeBuffer, fromPunycode.getCapacity(),
    713                                             NULL, &punycodeErrorCode);
    714         }
    715         fromPunycode.releaseBuffer(unicodeLength);
    716         if(U_FAILURE(punycodeErrorCode)) {
    717             info.labelErrors|=UIDNA_ERROR_PUNYCODE;
    718             return markBadACELabel(dest, labelStart, labelLength, toASCII, info);
    719         }
    720         // Check for NFC, and for characters that are not
    721         // valid or deviation characters according to the normalizer.
    722         // If there is something wrong, then the string will change.
    723         // Note that the normalizer passes through non-LDH ASCII and deviation characters.
    724         // Deviation characters are ok in Punycode even in transitional processing.
    725         // In the code further below, if we find non-LDH ASCII and we have UIDNA_USE_STD3_RULES
    726         // then we will set UIDNA_ERROR_INVALID_ACE_LABEL there too.
    727         UBool isValid=uts46Norm2.isNormalized(fromPunycode, errorCode);
    728         if(U_FAILURE(errorCode)) {
    729             return labelLength;
    730         }
    731         if(!isValid) {
    732             info.labelErrors|=UIDNA_ERROR_INVALID_ACE_LABEL;
    733             return markBadACELabel(dest, labelStart, labelLength, toASCII, info);
    734         }
    735         labelString=&fromPunycode;
    736         label=fromPunycode.getBuffer();
    737         labelStart=0;
    738         labelLength=fromPunycode.length();
    739     } else {
    740         wasPunycode=FALSE;
    741         labelString=&dest;
    742     }
    743     // Validity check
    744     if(labelLength==0) {
    745         if(toASCII) {
    746             info.labelErrors|=UIDNA_ERROR_EMPTY_LABEL;
    747         }
    748         return replaceLabel(dest, destLabelStart, destLabelLength, *labelString, labelLength);
    749     }
    750     // labelLength>0
    751     if(labelLength>=4 && label[2]==0x2d && label[3]==0x2d) {
    752         // label starts with "??--"
    753         info.labelErrors|=UIDNA_ERROR_HYPHEN_3_4;
    754     }
    755     if(label[0]==0x2d) {
    756         // label starts with "-"
    757         info.labelErrors|=UIDNA_ERROR_LEADING_HYPHEN;
    758     }
    759     if(label[labelLength-1]==0x2d) {
    760         // label ends with "-"
    761         info.labelErrors|=UIDNA_ERROR_TRAILING_HYPHEN;
    762     }
    763     // If the label was not a Punycode label, then it was the result of
    764     // mapping, normalization and label segmentation.
    765     // If the label was in Punycode, then we mapped it again above
    766     // and checked its validity.
    767     // Now we handle the STD3 restriction to LDH characters (if set)
    768     // and we look for U+FFFD which indicates disallowed characters
    769     // in a non-Punycode label or U+FFFD itself in a Punycode label.
    770     // We also check for dots which can come from the input to a single-label function.
    771     // Ok to cast away const because we own the UnicodeString.
    772     UChar *s=(UChar *)label;
    773     const UChar *limit=label+labelLength;
    774     UChar oredChars=0;
    775     // If we enforce STD3 rules, then ASCII characters other than LDH and dot are disallowed.
    776     UBool disallowNonLDHDot=(options&UIDNA_USE_STD3_RULES)!=0;
    777     do {
    778         UChar c=*s;
    779         if(c<=0x7f) {
    780             if(c==0x2e) {
    781                 info.labelErrors|=UIDNA_ERROR_LABEL_HAS_DOT;
    782                 *s=0xfffd;
    783             } else if(disallowNonLDHDot && asciiData[c]<0) {
    784                 info.labelErrors|=UIDNA_ERROR_DISALLOWED;
    785                 *s=0xfffd;
    786             }
    787         } else {
    788             oredChars|=c;
    789             if(disallowNonLDHDot && isNonASCIIDisallowedSTD3Valid(c)) {
    790                 info.labelErrors|=UIDNA_ERROR_DISALLOWED;
    791                 *s=0xfffd;
    792             } else if(c==0xfffd) {
    793                 info.labelErrors|=UIDNA_ERROR_DISALLOWED;
    794             }
    795         }
    796         ++s;
    797     } while(s<limit);
    798     // Check for a leading combining mark after other validity checks
    799     // so that we don't report UIDNA_ERROR_DISALLOWED for the U+FFFD from here.
    800     UChar32 c;
    801     int32_t cpLength=0;
    802     // "Unsafe" is ok because unpaired surrogates were mapped to U+FFFD.
    803     U16_NEXT_UNSAFE(label, cpLength, c);
    804     if((U_GET_GC_MASK(c)&U_GC_M_MASK)!=0) {
    805         info.labelErrors|=UIDNA_ERROR_LEADING_COMBINING_MARK;
    806         labelString->replace(labelStart, cpLength, (UChar)0xfffd);
    807         label=labelString->getBuffer()+labelStart;
    808         labelLength+=1-cpLength;
    809         if(labelString==&dest) {
    810             destLabelLength=labelLength;
    811         }
    812     }
    813     if((info.labelErrors&severeErrors)==0) {
    814         // Do contextual checks only if we do not have U+FFFD from a severe error
    815         // because U+FFFD can make these checks fail.
    816         if((options&UIDNA_CHECK_BIDI)!=0 && (!info.isBiDi || info.isOkBiDi)) {
    817             checkLabelBiDi(label, labelLength, info);
    818         }
    819         if( (options&UIDNA_CHECK_CONTEXTJ)!=0 && (oredChars&0x200c)==0x200c &&
    820             !isLabelOkContextJ(label, labelLength)
    821         ) {
    822             info.labelErrors|=UIDNA_ERROR_CONTEXTJ;
    823         }
    824         if(toASCII) {
    825             if(wasPunycode) {
    826                 // Leave a Punycode label unchanged if it has no severe errors.
    827                 if(destLabelLength>63) {
    828                     info.labelErrors|=UIDNA_ERROR_LABEL_TOO_LONG;
    829                 }
    830                 return destLabelLength;
    831             } else if(oredChars>=0x80) {
    832                 // Contains non-ASCII characters.
    833                 UnicodeString punycode;
    834                 UChar *buffer=punycode.getBuffer(63);  // 63==maximum DNS label length
    835                 if(buffer==NULL) {
    836                     errorCode=U_MEMORY_ALLOCATION_ERROR;
    837                     return destLabelLength;
    838                 }
    839                 buffer[0]=0x78;  // Write "xn--".
    840                 buffer[1]=0x6e;
    841                 buffer[2]=0x2d;
    842                 buffer[3]=0x2d;
    843                 int32_t punycodeLength=u_strToPunycode(label, labelLength,
    844                                                       buffer+4, punycode.getCapacity()-4,
    845                                                       NULL, &errorCode);
    846                 if(errorCode==U_BUFFER_OVERFLOW_ERROR) {
    847                     errorCode=U_ZERO_ERROR;
    848                     punycode.releaseBuffer(4);
    849                     buffer=punycode.getBuffer(4+punycodeLength);
    850                     if(buffer==NULL) {
    851                         errorCode=U_MEMORY_ALLOCATION_ERROR;
    852                         return destLabelLength;
    853                     }
    854                     punycodeLength=u_strToPunycode(label, labelLength,
    855                                                   buffer+4, punycode.getCapacity()-4,
    856                                                   NULL, &errorCode);
    857                 }
    858                 punycodeLength+=4;
    859                 punycode.releaseBuffer(punycodeLength);
    860                 if(U_FAILURE(errorCode)) {
    861                     return destLabelLength;
    862                 }
    863                 if(punycodeLength>63) {
    864                     info.labelErrors|=UIDNA_ERROR_LABEL_TOO_LONG;
    865                 }
    866                 return replaceLabel(dest, destLabelStart, destLabelLength,
    867                                     punycode, punycodeLength);
    868             } else {
    869                 // all-ASCII label
    870                 if(labelLength>63) {
    871                     info.labelErrors|=UIDNA_ERROR_LABEL_TOO_LONG;
    872                 }
    873             }
    874         }
    875     } else {
    876         // If a Punycode label has severe errors,
    877         // then leave it but make sure it does not look valid.
    878         if(wasPunycode) {
    879             info.labelErrors|=UIDNA_ERROR_INVALID_ACE_LABEL;
    880             return markBadACELabel(dest, destLabelStart, destLabelLength, toASCII, info);
    881         }
    882     }
    883     return replaceLabel(dest, destLabelStart, destLabelLength, *labelString, labelLength);
    884 }
    885 
    886 // Make sure an ACE label does not look valid.
    887 // Append U+FFFD if the label has only LDH characters.
    888 // If UIDNA_USE_STD3_RULES, also replace disallowed ASCII characters with U+FFFD.
    889 int32_t
    890 UTS46::markBadACELabel(UnicodeString &dest,
    891                        int32_t labelStart, int32_t labelLength,
    892                        UBool toASCII, IDNAInfo &info) const {
    893     UBool disallowNonLDHDot=(options&UIDNA_USE_STD3_RULES)!=0;
    894     UBool isASCII=TRUE;
    895     UBool onlyLDH=TRUE;
    896     const UChar *label=dest.getBuffer()+labelStart;
    897     // Ok to cast away const because we own the UnicodeString.
    898     UChar *s=(UChar *)label+4;  // After the initial "xn--".
    899     const UChar *limit=label+labelLength;
    900     do {
    901         UChar c=*s;
    902         if(c<=0x7f) {
    903             if(c==0x2e) {
    904                 info.labelErrors|=UIDNA_ERROR_LABEL_HAS_DOT;
    905                 *s=0xfffd;
    906                 isASCII=onlyLDH=FALSE;
    907             } else if(asciiData[c]<0) {
    908                 onlyLDH=FALSE;
    909                 if(disallowNonLDHDot) {
    910                     *s=0xfffd;
    911                     isASCII=FALSE;
    912                 }
    913             }
    914         } else {
    915             isASCII=onlyLDH=FALSE;
    916         }
    917     } while(++s<limit);
    918     if(onlyLDH) {
    919         dest.insert(labelStart+labelLength, (UChar)0xfffd);
    920         ++labelLength;
    921     } else {
    922         if(toASCII && isASCII && labelLength>63) {
    923             info.labelErrors|=UIDNA_ERROR_LABEL_TOO_LONG;
    924         }
    925     }
    926     return labelLength;
    927 }
    928 
    929 const uint32_t L_MASK=U_MASK(U_LEFT_TO_RIGHT);
    930 const uint32_t R_AL_MASK=U_MASK(U_RIGHT_TO_LEFT)|U_MASK(U_RIGHT_TO_LEFT_ARABIC);
    931 const uint32_t L_R_AL_MASK=L_MASK|R_AL_MASK;
    932 
    933 const uint32_t R_AL_AN_MASK=R_AL_MASK|U_MASK(U_ARABIC_NUMBER);
    934 
    935 const uint32_t EN_AN_MASK=U_MASK(U_EUROPEAN_NUMBER)|U_MASK(U_ARABIC_NUMBER);
    936 const uint32_t R_AL_EN_AN_MASK=R_AL_MASK|EN_AN_MASK;
    937 const uint32_t L_EN_MASK=L_MASK|U_MASK(U_EUROPEAN_NUMBER);
    938 
    939 const uint32_t ES_CS_ET_ON_BN_NSM_MASK=
    940     U_MASK(U_EUROPEAN_NUMBER_SEPARATOR)|
    941     U_MASK(U_COMMON_NUMBER_SEPARATOR)|
    942     U_MASK(U_EUROPEAN_NUMBER_TERMINATOR)|
    943     U_MASK(U_OTHER_NEUTRAL)|
    944     U_MASK(U_BOUNDARY_NEUTRAL)|
    945     U_MASK(U_DIR_NON_SPACING_MARK);
    946 const uint32_t L_EN_ES_CS_ET_ON_BN_NSM_MASK=L_EN_MASK|ES_CS_ET_ON_BN_NSM_MASK;
    947 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;
    948 
    949 // We scan the whole label and check both for whether it contains RTL characters
    950 // and whether it passes the BiDi Rule.
    951 // In a BiDi domain name, all labels must pass the BiDi Rule, but we might find
    952 // that a domain name is a BiDi domain name (has an RTL label) only after
    953 // processing several earlier labels.
    954 void
    955 UTS46::checkLabelBiDi(const UChar *label, int32_t labelLength, IDNAInfo &info) const {
    956     // IDNA2008 BiDi rule
    957     // Get the directionality of the first character.
    958     UChar32 c;
    959     int32_t i=0;
    960     U16_NEXT_UNSAFE(label, i, c);
    961     uint32_t firstMask=U_MASK(u_charDirection(c));
    962     // 1. The first character must be a character with BIDI property L, R
    963     // or AL.  If it has the R or AL property, it is an RTL label; if it
    964     // has the L property, it is an LTR label.
    965     if((firstMask&~L_R_AL_MASK)!=0) {
    966         info.isOkBiDi=FALSE;
    967     }
    968     // Get the directionality of the last non-NSM character.
    969     uint32_t lastMask;
    970     for(;;) {
    971         if(i>=labelLength) {
    972             lastMask=firstMask;
    973             break;
    974         }
    975         U16_PREV_UNSAFE(label, labelLength, c);
    976         UCharDirection dir=u_charDirection(c);
    977         if(dir!=U_DIR_NON_SPACING_MARK) {
    978             lastMask=U_MASK(dir);
    979             break;
    980         }
    981     }
    982     // 3. In an RTL label, the end of the label must be a character with
    983     // BIDI property R, AL, EN or AN, followed by zero or more
    984     // characters with BIDI property NSM.
    985     // 6. In an LTR label, the end of the label must be a character with
    986     // BIDI property L or EN, followed by zero or more characters with
    987     // BIDI property NSM.
    988     if( (firstMask&L_MASK)!=0 ?
    989             (lastMask&~L_EN_MASK)!=0 :
    990             (lastMask&~R_AL_EN_AN_MASK)!=0
    991     ) {
    992         info.isOkBiDi=FALSE;
    993     }
    994     // Get the directionalities of the intervening characters.
    995     uint32_t mask=0;
    996     while(i<labelLength) {
    997         U16_NEXT_UNSAFE(label, i, c);
    998         mask|=U_MASK(u_charDirection(c));
    999     }
   1000     if(firstMask&L_MASK) {
   1001         // 5. In an LTR label, only characters with the BIDI properties L, EN,
   1002         // ES, CS, ET, ON, BN and NSM are allowed.
   1003         if((mask&~L_EN_ES_CS_ET_ON_BN_NSM_MASK)!=0) {
   1004             info.isOkBiDi=FALSE;
   1005         }
   1006     } else {
   1007         // 2. In an RTL label, only characters with the BIDI properties R, AL,
   1008         // AN, EN, ES, CS, ET, ON, BN and NSM are allowed.
   1009         if((mask&~R_AL_AN_EN_ES_CS_ET_ON_BN_NSM_MASK)!=0) {
   1010             info.isOkBiDi=FALSE;
   1011         }
   1012         // 4. In an RTL label, if an EN is present, no AN may be present, and
   1013         // vice versa.
   1014         if((mask&EN_AN_MASK)==EN_AN_MASK) {
   1015             info.isOkBiDi=FALSE;
   1016         }
   1017     }
   1018     // An RTL label is a label that contains at least one character of type
   1019     // R, AL or AN. [...]
   1020     // A "BIDI domain name" is a domain name that contains at least one RTL
   1021     // label. [...]
   1022     // The following rule, consisting of six conditions, applies to labels
   1023     // in BIDI domain names.
   1024     if(((firstMask|mask|lastMask)&R_AL_AN_MASK)!=0) {
   1025         info.isBiDi=TRUE;
   1026     }
   1027 }
   1028 
   1029 // Special code for the ASCII prefix of a BiDi domain name.
   1030 // The ASCII prefix is all-LTR.
   1031 
   1032 // IDNA2008 BiDi rule, parts relevant to ASCII labels:
   1033 // 1. The first character must be a character with BIDI property L [...]
   1034 // 5. In an LTR label, only characters with the BIDI properties L, EN,
   1035 // ES, CS, ET, ON, BN and NSM are allowed.
   1036 // 6. In an LTR label, the end of the label must be a character with
   1037 // BIDI property L or EN [...]
   1038 
   1039 // UTF-16 version, called for mapped ASCII prefix.
   1040 // Cannot contain uppercase A-Z.
   1041 // s[length-1] must be the trailing dot.
   1042 static UBool
   1043 isASCIIOkBiDi(const UChar *s, int32_t length) {
   1044     int32_t labelStart=0;
   1045     for(int32_t i=0; i<length; ++i) {
   1046         UChar c=s[i];
   1047         if(c==0x2e) {  // dot
   1048             if(i>labelStart) {
   1049                 c=s[i-1];
   1050                 if(!(0x61<=c && c<=0x7a) && !(0x30<=c && c<=0x39)) {
   1051                     // Last character in the label is not an L or EN.
   1052                     return FALSE;
   1053                 }
   1054             }
   1055             labelStart=i+1;
   1056         } else if(i==labelStart) {
   1057             if(!(0x61<=c && c<=0x7a)) {
   1058                 // First character in the label is not an L.
   1059                 return FALSE;
   1060             }
   1061         } else {
   1062             if(c<=0x20 && (c>=0x1c || (9<=c && c<=0xd))) {
   1063                 // Intermediate character in the label is a B, S or WS.
   1064                 return FALSE;
   1065             }
   1066         }
   1067     }
   1068     return TRUE;
   1069 }
   1070 
   1071 // UTF-8 version, called for source ASCII prefix.
   1072 // Can contain uppercase A-Z.
   1073 // s[length-1] must be the trailing dot.
   1074 static UBool
   1075 isASCIIOkBiDi(const char *s, int32_t length) {
   1076     int32_t labelStart=0;
   1077     for(int32_t i=0; i<length; ++i) {
   1078         char c=s[i];
   1079         if(c==0x2e) {  // dot
   1080             if(i>labelStart) {
   1081                 c=s[i-1];
   1082                 if(!(0x61<=c && c<=0x7a) && !(0x41<=c && c<=0x5a) && !(0x30<=c && c<=0x39)) {
   1083                     // Last character in the label is not an L or EN.
   1084                     return FALSE;
   1085                 }
   1086             }
   1087             labelStart=i+1;
   1088         } else if(i==labelStart) {
   1089             if(!(0x61<=c && c<=0x7a) && !(0x41<=c && c<=0x5a)) {
   1090                 // First character in the label is not an L.
   1091                 return FALSE;
   1092             }
   1093         } else {
   1094             if(c<=0x20 && (c>=0x1c || (9<=c && c<=0xd))) {
   1095                 // Intermediate character in the label is a B, S or WS.
   1096                 return FALSE;
   1097             }
   1098         }
   1099     }
   1100     return TRUE;
   1101 }
   1102 
   1103 UBool
   1104 UTS46::isLabelOkContextJ(const UChar *label, int32_t labelLength) const {
   1105     // [IDNA2008-Tables]
   1106     // 200C..200D  ; CONTEXTJ    # ZERO WIDTH NON-JOINER..ZERO WIDTH JOINER
   1107     for(int32_t i=0; i<labelLength; ++i) {
   1108         if(label[i]==0x200c) {
   1109             // Appendix A.1. ZERO WIDTH NON-JOINER
   1110             // Rule Set:
   1111             //  False;
   1112             //  If Canonical_Combining_Class(Before(cp)) .eq.  Virama Then True;
   1113             //  If RegExpMatch((Joining_Type:{L,D})(Joining_Type:T)*\u200C
   1114             //     (Joining_Type:T)*(Joining_Type:{R,D})) Then True;
   1115             if(i==0) {
   1116                 return FALSE;
   1117             }
   1118             UChar32 c;
   1119             int32_t j=i;
   1120             U16_PREV_UNSAFE(label, j, c);
   1121             if(u_getCombiningClass(c)==9) {
   1122                 continue;
   1123             }
   1124             // check precontext (Joining_Type:{L,D})(Joining_Type:T)*
   1125             for(;;) {
   1126                 UJoiningType type=(UJoiningType)u_getIntPropertyValue(c, UCHAR_JOINING_TYPE);
   1127                 if(type==U_JT_TRANSPARENT) {
   1128                     if(j==0) {
   1129                         return FALSE;
   1130                     }
   1131                     U16_PREV_UNSAFE(label, j, c);
   1132                 } else if(type==U_JT_LEFT_JOINING || type==U_JT_DUAL_JOINING) {
   1133                     break;  // precontext fulfilled
   1134                 } else {
   1135                     return FALSE;
   1136                 }
   1137             }
   1138             // check postcontext (Joining_Type:T)*(Joining_Type:{R,D})
   1139             for(j=i+1;;) {
   1140                 if(j==labelLength) {
   1141                     return FALSE;
   1142                 }
   1143                 U16_NEXT_UNSAFE(label, j, c);
   1144                 UJoiningType type=(UJoiningType)u_getIntPropertyValue(c, UCHAR_JOINING_TYPE);
   1145                 if(type==U_JT_TRANSPARENT) {
   1146                     // just skip this character
   1147                 } else if(type==U_JT_RIGHT_JOINING || type==U_JT_DUAL_JOINING) {
   1148                     break;  // postcontext fulfilled
   1149                 } else {
   1150                     return FALSE;
   1151                 }
   1152             }
   1153         } else if(label[i]==0x200d) {
   1154             // Appendix A.2. ZERO WIDTH JOINER (U+200D)
   1155             // Rule Set:
   1156             //  False;
   1157             //  If Canonical_Combining_Class(Before(cp)) .eq.  Virama Then True;
   1158             if(i==0) {
   1159                 return FALSE;
   1160             }
   1161             UChar32 c;
   1162             int32_t j=i;
   1163             U16_PREV_UNSAFE(label, j, c);
   1164             if(u_getCombiningClass(c)!=9) {
   1165                 return FALSE;
   1166             }
   1167         }
   1168     }
   1169     return TRUE;
   1170 }
   1171 
   1172 U_NAMESPACE_END
   1173 
   1174 // C API ------------------------------------------------------------------- ***
   1175 
   1176 U_NAMESPACE_USE
   1177 
   1178 U_DRAFT UIDNA * U_EXPORT2
   1179 uidna_openUTS46(uint32_t options, UErrorCode *pErrorCode) {
   1180     return reinterpret_cast<UIDNA *>(IDNA::createUTS46Instance(options, *pErrorCode));
   1181 }
   1182 
   1183 U_DRAFT void U_EXPORT2
   1184 uidna_close(UIDNA *idna) {
   1185     delete reinterpret_cast<IDNA *>(idna);
   1186 }
   1187 
   1188 static UBool
   1189 checkArgs(const void *label, int32_t length,
   1190           void *dest, int32_t capacity,
   1191           UIDNAInfo *pInfo, UErrorCode *pErrorCode) {
   1192     if(U_FAILURE(*pErrorCode)) {
   1193         return FALSE;
   1194     }
   1195     // sizeof(UIDNAInfo)=16 in the first API version.
   1196     if(pInfo==NULL || pInfo->size<16) {
   1197         *pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
   1198         return FALSE;
   1199     }
   1200     if( (label==NULL ? length!=0 : length<-1) ||
   1201         (dest==NULL ? capacity!=0 : capacity<0) ||
   1202         (dest==label && label!=NULL)
   1203     ) {
   1204         *pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
   1205         return FALSE;
   1206     }
   1207     // Set all *pInfo bytes to 0 except for the size field itself.
   1208     uprv_memset(&pInfo->size+1, 0, pInfo->size-sizeof(pInfo->size));
   1209     return TRUE;
   1210 }
   1211 
   1212 static void
   1213 idnaInfoToStruct(IDNAInfo &info, UIDNAInfo *pInfo) {
   1214     pInfo->isTransitionalDifferent=info.isTransitionalDifferent();
   1215     pInfo->errors=info.getErrors();
   1216 }
   1217 
   1218 U_DRAFT int32_t U_EXPORT2
   1219 uidna_labelToASCII(const UIDNA *idna,
   1220                    const UChar *label, int32_t length,
   1221                    UChar *dest, int32_t capacity,
   1222                    UIDNAInfo *pInfo, UErrorCode *pErrorCode) {
   1223     if(!checkArgs(label, length, dest, capacity, pInfo, pErrorCode)) {
   1224         return 0;
   1225     }
   1226     UnicodeString src((UBool)(length<0), label, length);
   1227     UnicodeString destString(dest, 0, capacity);
   1228     IDNAInfo info;
   1229     reinterpret_cast<const IDNA *>(idna)->labelToASCII(src, destString, info, *pErrorCode);
   1230     idnaInfoToStruct(info, pInfo);
   1231     return destString.extract(dest, capacity, *pErrorCode);
   1232 }
   1233 
   1234 U_DRAFT int32_t U_EXPORT2
   1235 uidna_labelToUnicode(const UIDNA *idna,
   1236                      const UChar *label, int32_t length,
   1237                      UChar *dest, int32_t capacity,
   1238                      UIDNAInfo *pInfo, UErrorCode *pErrorCode) {
   1239     if(!checkArgs(label, length, dest, capacity, pInfo, pErrorCode)) {
   1240         return 0;
   1241     }
   1242     UnicodeString src((UBool)(length<0), label, length);
   1243     UnicodeString destString(dest, 0, capacity);
   1244     IDNAInfo info;
   1245     reinterpret_cast<const IDNA *>(idna)->labelToUnicode(src, destString, info, *pErrorCode);
   1246     idnaInfoToStruct(info, pInfo);
   1247     return destString.extract(dest, capacity, *pErrorCode);
   1248 }
   1249 
   1250 U_DRAFT int32_t U_EXPORT2
   1251 uidna_nameToASCII(const UIDNA *idna,
   1252                   const UChar *name, int32_t length,
   1253                   UChar *dest, int32_t capacity,
   1254                   UIDNAInfo *pInfo, UErrorCode *pErrorCode) {
   1255     if(!checkArgs(name, length, dest, capacity, pInfo, pErrorCode)) {
   1256         return 0;
   1257     }
   1258     UnicodeString src((UBool)(length<0), name, length);
   1259     UnicodeString destString(dest, 0, capacity);
   1260     IDNAInfo info;
   1261     reinterpret_cast<const IDNA *>(idna)->nameToASCII(src, destString, info, *pErrorCode);
   1262     idnaInfoToStruct(info, pInfo);
   1263     return destString.extract(dest, capacity, *pErrorCode);
   1264 }
   1265 
   1266 U_DRAFT int32_t U_EXPORT2
   1267 uidna_nameToUnicode(const UIDNA *idna,
   1268                     const UChar *name, int32_t length,
   1269                     UChar *dest, int32_t capacity,
   1270                     UIDNAInfo *pInfo, UErrorCode *pErrorCode) {
   1271     if(!checkArgs(name, length, dest, capacity, pInfo, pErrorCode)) {
   1272         return 0;
   1273     }
   1274     UnicodeString src((UBool)(length<0), name, length);
   1275     UnicodeString destString(dest, 0, capacity);
   1276     IDNAInfo info;
   1277     reinterpret_cast<const IDNA *>(idna)->nameToUnicode(src, destString, info, *pErrorCode);
   1278     idnaInfoToStruct(info, pInfo);
   1279     return destString.extract(dest, capacity, *pErrorCode);
   1280 }
   1281 
   1282 U_DRAFT int32_t U_EXPORT2
   1283 uidna_labelToASCII_UTF8(const UIDNA *idna,
   1284                         const char *label, int32_t length,
   1285                         char *dest, int32_t capacity,
   1286                         UIDNAInfo *pInfo, UErrorCode *pErrorCode) {
   1287     if(!checkArgs(label, length, dest, capacity, pInfo, pErrorCode)) {
   1288         return 0;
   1289     }
   1290     StringPiece src(label, length<0 ? uprv_strlen(label) : length);
   1291     CheckedArrayByteSink sink(dest, capacity);
   1292     IDNAInfo info;
   1293     reinterpret_cast<const IDNA *>(idna)->labelToASCII_UTF8(src, sink, info, *pErrorCode);
   1294     idnaInfoToStruct(info, pInfo);
   1295     return u_terminateChars(dest, capacity, sink.NumberOfBytesAppended(), pErrorCode);
   1296 }
   1297 
   1298 U_DRAFT int32_t U_EXPORT2
   1299 uidna_labelToUnicodeUTF8(const UIDNA *idna,
   1300                          const char *label, int32_t length,
   1301                          char *dest, int32_t capacity,
   1302                          UIDNAInfo *pInfo, UErrorCode *pErrorCode) {
   1303     if(!checkArgs(label, length, dest, capacity, pInfo, pErrorCode)) {
   1304         return 0;
   1305     }
   1306     StringPiece src(label, length<0 ? uprv_strlen(label) : length);
   1307     CheckedArrayByteSink sink(dest, capacity);
   1308     IDNAInfo info;
   1309     reinterpret_cast<const IDNA *>(idna)->labelToUnicodeUTF8(src, sink, info, *pErrorCode);
   1310     idnaInfoToStruct(info, pInfo);
   1311     return u_terminateChars(dest, capacity, sink.NumberOfBytesAppended(), pErrorCode);
   1312 }
   1313 
   1314 U_DRAFT int32_t U_EXPORT2
   1315 uidna_nameToASCII_UTF8(const UIDNA *idna,
   1316                        const char *name, int32_t length,
   1317                        char *dest, int32_t capacity,
   1318                        UIDNAInfo *pInfo, UErrorCode *pErrorCode) {
   1319     if(!checkArgs(name, length, dest, capacity, pInfo, pErrorCode)) {
   1320         return 0;
   1321     }
   1322     StringPiece src(name, length<0 ? uprv_strlen(name) : length);
   1323     CheckedArrayByteSink sink(dest, capacity);
   1324     IDNAInfo info;
   1325     reinterpret_cast<const IDNA *>(idna)->nameToASCII_UTF8(src, sink, info, *pErrorCode);
   1326     idnaInfoToStruct(info, pInfo);
   1327     return u_terminateChars(dest, capacity, sink.NumberOfBytesAppended(), pErrorCode);
   1328 }
   1329 
   1330 U_DRAFT int32_t U_EXPORT2
   1331 uidna_nameToUnicodeUTF8(const UIDNA *idna,
   1332                         const char *name, int32_t length,
   1333                         char *dest, int32_t capacity,
   1334                         UIDNAInfo *pInfo, UErrorCode *pErrorCode) {
   1335     if(!checkArgs(name, length, dest, capacity, pInfo, pErrorCode)) {
   1336         return 0;
   1337     }
   1338     StringPiece src(name, length<0 ? uprv_strlen(name) : length);
   1339     CheckedArrayByteSink sink(dest, capacity);
   1340     IDNAInfo info;
   1341     reinterpret_cast<const IDNA *>(idna)->nameToUnicodeUTF8(src, sink, info, *pErrorCode);
   1342     idnaInfoToStruct(info, pInfo);
   1343     return u_terminateChars(dest, capacity, sink.NumberOfBytesAppended(), pErrorCode);
   1344 }
   1345 
   1346 #endif  // UCONFIG_NO_IDNA
   1347