1/*
2*******************************************************************************
3*   Copyright (C) 2010-2012, 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/uscript.h"
22#include "unicode/ustring.h"
23#include "unicode/utf16.h"
24#include "cmemory.h"
25#include "cstring.h"
26#include "punycode.h"
27#include "ubidi_props.h"
28#include "ustr_imp.h"
29
30#define LENGTHOF(array) (int32_t)(sizeof(array)/sizeof((array)[0]))
31
32// Note about tests for UIDNA_ERROR_DOMAIN_NAME_TOO_LONG:
33//
34// The domain name length limit is 255 octets in an internal DNS representation
35// where the last ("root") label is the empty label
36// represented by length byte 0 alone.
37// In a conventional string, this translates to 253 characters, or 254
38// if there is a trailing dot for the root label.
39
40U_NAMESPACE_BEGIN
41
42// Severe errors which usually result in a U+FFFD replacement character in the result string.
43const uint32_t severeErrors=
44    UIDNA_ERROR_LEADING_COMBINING_MARK|
45    UIDNA_ERROR_DISALLOWED|
46    UIDNA_ERROR_PUNYCODE|
47    UIDNA_ERROR_LABEL_HAS_DOT|
48    UIDNA_ERROR_INVALID_ACE_LABEL;
49
50static inline UBool
51isASCIIString(const UnicodeString &dest) {
52    const UChar *s=dest.getBuffer();
53    const UChar *limit=s+dest.length();
54    while(s<limit) {
55        if(*s++>0x7f) {
56            return FALSE;
57        }
58    }
59    return TRUE;
60}
61
62static UBool
63isASCIIOkBiDi(const UChar *s, int32_t length);
64
65static UBool
66isASCIIOkBiDi(const char *s, int32_t length);
67
68// IDNA class default implementations -------------------------------------- ***
69
70IDNA::~IDNA() {}
71
72void
73IDNA::labelToASCII_UTF8(const StringPiece &label, ByteSink &dest,
74                        IDNAInfo &info, UErrorCode &errorCode) const {
75    if(U_SUCCESS(errorCode)) {
76        UnicodeString destString;
77        labelToASCII(UnicodeString::fromUTF8(label), destString,
78                     info, errorCode).toUTF8(dest);
79    }
80}
81
82void
83IDNA::labelToUnicodeUTF8(const StringPiece &label, ByteSink &dest,
84                         IDNAInfo &info, UErrorCode &errorCode) const {
85    if(U_SUCCESS(errorCode)) {
86        UnicodeString destString;
87        labelToUnicode(UnicodeString::fromUTF8(label), destString,
88                       info, errorCode).toUTF8(dest);
89    }
90}
91
92void
93IDNA::nameToASCII_UTF8(const StringPiece &name, ByteSink &dest,
94                       IDNAInfo &info, UErrorCode &errorCode) const {
95    if(U_SUCCESS(errorCode)) {
96        UnicodeString destString;
97        nameToASCII(UnicodeString::fromUTF8(name), destString,
98                    info, errorCode).toUTF8(dest);
99    }
100}
101
102void
103IDNA::nameToUnicodeUTF8(const StringPiece &name, ByteSink &dest,
104                        IDNAInfo &info, UErrorCode &errorCode) const {
105    if(U_SUCCESS(errorCode)) {
106        UnicodeString destString;
107        nameToUnicode(UnicodeString::fromUTF8(name), destString,
108                      info, errorCode).toUTF8(dest);
109    }
110}
111
112// UTS46 class declaration ------------------------------------------------- ***
113
114class UTS46 : public IDNA {
115public:
116    UTS46(uint32_t options, UErrorCode &errorCode);
117    virtual ~UTS46();
118
119    virtual UnicodeString &
120    labelToASCII(const UnicodeString &label, UnicodeString &dest,
121                 IDNAInfo &info, UErrorCode &errorCode) const;
122
123    virtual UnicodeString &
124    labelToUnicode(const UnicodeString &label, UnicodeString &dest,
125                   IDNAInfo &info, UErrorCode &errorCode) const;
126
127    virtual UnicodeString &
128    nameToASCII(const UnicodeString &name, UnicodeString &dest,
129                IDNAInfo &info, UErrorCode &errorCode) const;
130
131    virtual UnicodeString &
132    nameToUnicode(const UnicodeString &name, UnicodeString &dest,
133                  IDNAInfo &info, UErrorCode &errorCode) const;
134
135    virtual void
136    labelToASCII_UTF8(const StringPiece &label, ByteSink &dest,
137                      IDNAInfo &info, UErrorCode &errorCode) const;
138
139    virtual void
140    labelToUnicodeUTF8(const StringPiece &label, ByteSink &dest,
141                       IDNAInfo &info, UErrorCode &errorCode) const;
142
143    virtual void
144    nameToASCII_UTF8(const StringPiece &name, ByteSink &dest,
145                     IDNAInfo &info, UErrorCode &errorCode) const;
146
147    virtual void
148    nameToUnicodeUTF8(const StringPiece &name, ByteSink &dest,
149                      IDNAInfo &info, UErrorCode &errorCode) const;
150
151private:
152    UnicodeString &
153    process(const UnicodeString &src,
154            UBool isLabel, UBool toASCII,
155            UnicodeString &dest,
156            IDNAInfo &info, UErrorCode &errorCode) const;
157
158    void
159    processUTF8(const StringPiece &src,
160                UBool isLabel, UBool toASCII,
161                ByteSink &dest,
162                IDNAInfo &info, UErrorCode &errorCode) const;
163
164    UnicodeString &
165    processUnicode(const UnicodeString &src,
166                   int32_t labelStart, int32_t mappingStart,
167                   UBool isLabel, UBool toASCII,
168                   UnicodeString &dest,
169                   IDNAInfo &info, UErrorCode &errorCode) const;
170
171    // returns the new dest.length()
172    int32_t
173    mapDevChars(UnicodeString &dest, int32_t labelStart, int32_t mappingStart,
174                UErrorCode &errorCode) const;
175
176    // returns the new label length
177    int32_t
178    processLabel(UnicodeString &dest,
179                 int32_t labelStart, int32_t labelLength,
180                 UBool toASCII,
181                 IDNAInfo &info, UErrorCode &errorCode) const;
182    int32_t
183    markBadACELabel(UnicodeString &dest,
184                    int32_t labelStart, int32_t labelLength,
185                    UBool toASCII, IDNAInfo &info) const;
186
187    void
188    checkLabelBiDi(const UChar *label, int32_t labelLength, IDNAInfo &info) const;
189
190    UBool
191    isLabelOkContextJ(const UChar *label, int32_t labelLength) const;
192
193    void
194    checkLabelContextO(const UChar *label, int32_t labelLength, IDNAInfo &info) const;
195
196    const Normalizer2 &uts46Norm2;  // uts46.nrm
197    uint32_t options;
198};
199
200IDNA *
201IDNA::createUTS46Instance(uint32_t options, UErrorCode &errorCode) {
202    if(U_SUCCESS(errorCode)) {
203        IDNA *idna=new UTS46(options, errorCode);
204        if(idna==NULL) {
205            errorCode=U_MEMORY_ALLOCATION_ERROR;
206        } else if(U_FAILURE(errorCode)) {
207            delete idna;
208            idna=NULL;
209        }
210        return idna;
211    } else {
212        return NULL;
213    }
214}
215
216// UTS46 implementation ---------------------------------------------------- ***
217
218UTS46::UTS46(uint32_t opt, UErrorCode &errorCode)
219        : uts46Norm2(*Normalizer2::getInstance(NULL, "uts46", UNORM2_COMPOSE, errorCode)),
220          options(opt) {}
221
222UTS46::~UTS46() {}
223
224UnicodeString &
225UTS46::labelToASCII(const UnicodeString &label, UnicodeString &dest,
226                    IDNAInfo &info, UErrorCode &errorCode) const {
227    return process(label, TRUE, TRUE, dest, info, errorCode);
228}
229
230UnicodeString &
231UTS46::labelToUnicode(const UnicodeString &label, UnicodeString &dest,
232                      IDNAInfo &info, UErrorCode &errorCode) const {
233    return process(label, TRUE, FALSE, dest, info, errorCode);
234}
235
236UnicodeString &
237UTS46::nameToASCII(const UnicodeString &name, UnicodeString &dest,
238                   IDNAInfo &info, UErrorCode &errorCode) const {
239    process(name, FALSE, TRUE, dest, info, errorCode);
240    if( dest.length()>=254 && (info.errors&UIDNA_ERROR_DOMAIN_NAME_TOO_LONG)==0 &&
241        isASCIIString(dest) &&
242        (dest.length()>254 || dest[253]!=0x2e)
243    ) {
244        info.errors|=UIDNA_ERROR_DOMAIN_NAME_TOO_LONG;
245    }
246    return dest;
247}
248
249UnicodeString &
250UTS46::nameToUnicode(const UnicodeString &name, UnicodeString &dest,
251                     IDNAInfo &info, UErrorCode &errorCode) const {
252    return process(name, FALSE, FALSE, dest, info, errorCode);
253}
254
255void
256UTS46::labelToASCII_UTF8(const StringPiece &label, ByteSink &dest,
257                         IDNAInfo &info, UErrorCode &errorCode) const {
258    processUTF8(label, TRUE, TRUE, dest, info, errorCode);
259}
260
261void
262UTS46::labelToUnicodeUTF8(const StringPiece &label, ByteSink &dest,
263                          IDNAInfo &info, UErrorCode &errorCode) const {
264    processUTF8(label, TRUE, FALSE, dest, info, errorCode);
265}
266
267void
268UTS46::nameToASCII_UTF8(const StringPiece &name, ByteSink &dest,
269                        IDNAInfo &info, UErrorCode &errorCode) const {
270    processUTF8(name, FALSE, TRUE, dest, info, errorCode);
271}
272
273void
274UTS46::nameToUnicodeUTF8(const StringPiece &name, ByteSink &dest,
275                         IDNAInfo &info, UErrorCode &errorCode) const {
276    processUTF8(name, FALSE, FALSE, dest, info, errorCode);
277}
278
279// UTS #46 data for ASCII characters.
280// The normalizer (using uts46.nrm) maps uppercase ASCII letters to lowercase
281// and passes through all other ASCII characters.
282// If UIDNA_USE_STD3_RULES is set, then non-LDH characters are disallowed
283// using this data.
284// The ASCII fastpath also uses this data.
285// Values: -1=disallowed  0==valid  1==mapped (lowercase)
286static const int8_t asciiData[128]={
287    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
288    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
289    // 002D..002E; valid  #  HYPHEN-MINUS..FULL STOP
290    -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  0,  0, -1,
291    // 0030..0039; valid  #  DIGIT ZERO..DIGIT NINE
292     0,  0,  0,  0,  0,  0,  0,  0,  0,  0, -1, -1, -1, -1, -1, -1,
293    // 0041..005A; mapped  #  LATIN CAPITAL LETTER A..LATIN CAPITAL LETTER Z
294    -1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
295     1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1, -1, -1, -1, -1, -1,
296    // 0061..007A; valid  #  LATIN SMALL LETTER A..LATIN SMALL LETTER Z
297    -1,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
298     0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0, -1, -1, -1, -1, -1
299};
300
301UnicodeString &
302UTS46::process(const UnicodeString &src,
303               UBool isLabel, UBool toASCII,
304               UnicodeString &dest,
305               IDNAInfo &info, UErrorCode &errorCode) const {
306    // uts46Norm2.normalize() would do all of this error checking and setup,
307    // but with the ASCII fastpath we do not always call it, and do not
308    // call it first.
309    if(U_FAILURE(errorCode)) {
310        dest.setToBogus();
311        return dest;
312    }
313    const UChar *srcArray=src.getBuffer();
314    if(&dest==&src || srcArray==NULL) {
315        errorCode=U_ILLEGAL_ARGUMENT_ERROR;
316        dest.setToBogus();
317        return dest;
318    }
319    // Arguments are fine, reset output values.
320    dest.remove();
321    info.reset();
322    int32_t srcLength=src.length();
323    if(srcLength==0) {
324        if(toASCII) {
325            info.errors|=UIDNA_ERROR_EMPTY_LABEL;
326        }
327        return dest;
328    }
329    UChar *destArray=dest.getBuffer(srcLength);
330    if(destArray==NULL) {
331        errorCode=U_MEMORY_ALLOCATION_ERROR;
332        return dest;
333    }
334    // ASCII fastpath
335    UBool disallowNonLDHDot=(options&UIDNA_USE_STD3_RULES)!=0;
336    int32_t labelStart=0;
337    int32_t i;
338    for(i=0;; ++i) {
339        if(i==srcLength) {
340            if(toASCII) {
341                if((i-labelStart)>63) {
342                    info.labelErrors|=UIDNA_ERROR_LABEL_TOO_LONG;
343                }
344                // There is a trailing dot if labelStart==i.
345                if(!isLabel && i>=254 && (i>254 || labelStart<i)) {
346                    info.errors|=UIDNA_ERROR_DOMAIN_NAME_TOO_LONG;
347                }
348            }
349            info.errors|=info.labelErrors;
350            dest.releaseBuffer(i);
351            return dest;
352        }
353        UChar c=srcArray[i];
354        if(c>0x7f) {
355            break;
356        }
357        int cData=asciiData[c];
358        if(cData>0) {
359            destArray[i]=c+0x20;  // Lowercase an uppercase ASCII letter.
360        } else if(cData<0 && disallowNonLDHDot) {
361            break;  // Replacing with U+FFFD can be complicated for toASCII.
362        } else {
363            destArray[i]=c;
364            if(c==0x2d) {  // hyphen
365                if(i==(labelStart+3) && srcArray[i-1]==0x2d) {
366                    // "??--..." is Punycode or forbidden.
367                    ++i;  // '-' was copied to dest already
368                    break;
369                }
370                if(i==labelStart) {
371                    // label starts with "-"
372                    info.labelErrors|=UIDNA_ERROR_LEADING_HYPHEN;
373                }
374                if((i+1)==srcLength || srcArray[i+1]==0x2e) {
375                    // label ends with "-"
376                    info.labelErrors|=UIDNA_ERROR_TRAILING_HYPHEN;
377                }
378            } else if(c==0x2e) {  // dot
379                if(isLabel) {
380                    // Replacing with U+FFFD can be complicated for toASCII.
381                    ++i;  // '.' was copied to dest already
382                    break;
383                }
384                if(toASCII) {
385                    // Permit an empty label at the end but not elsewhere.
386                    if(i==labelStart && i<(srcLength-1)) {
387                        info.labelErrors|=UIDNA_ERROR_EMPTY_LABEL;
388                    } else if((i-labelStart)>63) {
389                        info.labelErrors|=UIDNA_ERROR_LABEL_TOO_LONG;
390                    }
391                }
392                info.errors|=info.labelErrors;
393                info.labelErrors=0;
394                labelStart=i+1;
395            }
396        }
397    }
398    info.errors|=info.labelErrors;
399    dest.releaseBuffer(i);
400    processUnicode(src, labelStart, i, isLabel, toASCII, dest, info, errorCode);
401    if( info.isBiDi && U_SUCCESS(errorCode) && (info.errors&severeErrors)==0 &&
402        (!info.isOkBiDi || (labelStart>0 && !isASCIIOkBiDi(dest.getBuffer(), labelStart)))
403    ) {
404        info.errors|=UIDNA_ERROR_BIDI;
405    }
406    return dest;
407}
408
409void
410UTS46::processUTF8(const StringPiece &src,
411                   UBool isLabel, UBool toASCII,
412                   ByteSink &dest,
413                   IDNAInfo &info, UErrorCode &errorCode) const {
414    if(U_FAILURE(errorCode)) {
415        return;
416    }
417    const char *srcArray=src.data();
418    int32_t srcLength=src.length();
419    if(srcArray==NULL && srcLength!=0) {
420        errorCode=U_ILLEGAL_ARGUMENT_ERROR;
421        return;
422    }
423    // Arguments are fine, reset output values.
424    info.reset();
425    if(srcLength==0) {
426        if(toASCII) {
427            info.errors|=UIDNA_ERROR_EMPTY_LABEL;
428        }
429        dest.Flush();
430        return;
431    }
432    UnicodeString destString;
433    int32_t labelStart=0;
434    if(srcLength<=256) {  // length of stackArray[]
435        // ASCII fastpath
436        char stackArray[256];
437        int32_t destCapacity;
438        char *destArray=dest.GetAppendBuffer(srcLength, srcLength+20,
439                                             stackArray, LENGTHOF(stackArray), &destCapacity);
440        UBool disallowNonLDHDot=(options&UIDNA_USE_STD3_RULES)!=0;
441        int32_t i;
442        for(i=0;; ++i) {
443            if(i==srcLength) {
444                if(toASCII) {
445                    if((i-labelStart)>63) {
446                        info.labelErrors|=UIDNA_ERROR_LABEL_TOO_LONG;
447                    }
448                    // There is a trailing dot if labelStart==i.
449                    if(!isLabel && i>=254 && (i>254 || labelStart<i)) {
450                        info.errors|=UIDNA_ERROR_DOMAIN_NAME_TOO_LONG;
451                    }
452                }
453                info.errors|=info.labelErrors;
454                dest.Append(destArray, i);
455                dest.Flush();
456                return;
457            }
458            char c=srcArray[i];
459            if((int8_t)c<0) {  // (uint8_t)c>0x7f
460                break;
461            }
462            int cData=asciiData[(int)c];  // Cast: gcc warns about indexing with a char.
463            if(cData>0) {
464                destArray[i]=c+0x20;  // Lowercase an uppercase ASCII letter.
465            } else if(cData<0 && disallowNonLDHDot) {
466                break;  // Replacing with U+FFFD can be complicated for toASCII.
467            } else {
468                destArray[i]=c;
469                if(c==0x2d) {  // hyphen
470                    if(i==(labelStart+3) && srcArray[i-1]==0x2d) {
471                        // "??--..." is Punycode or forbidden.
472                        break;
473                    }
474                    if(i==labelStart) {
475                        // label starts with "-"
476                        info.labelErrors|=UIDNA_ERROR_LEADING_HYPHEN;
477                    }
478                    if((i+1)==srcLength || srcArray[i+1]==0x2e) {
479                        // label ends with "-"
480                        info.labelErrors|=UIDNA_ERROR_TRAILING_HYPHEN;
481                    }
482                } else if(c==0x2e) {  // dot
483                    if(isLabel) {
484                        break;  // Replacing with U+FFFD can be complicated for toASCII.
485                    }
486                    if(toASCII) {
487                        // Permit an empty label at the end but not elsewhere.
488                        if(i==labelStart && i<(srcLength-1)) {
489                            info.labelErrors|=UIDNA_ERROR_EMPTY_LABEL;
490                        } else if((i-labelStart)>63) {
491                            info.labelErrors|=UIDNA_ERROR_LABEL_TOO_LONG;
492                        }
493                    }
494                    info.errors|=info.labelErrors;
495                    info.labelErrors=0;
496                    labelStart=i+1;
497                }
498            }
499        }
500        info.errors|=info.labelErrors;
501        // Convert the processed ASCII prefix of the current label to UTF-16.
502        int32_t mappingStart=i-labelStart;
503        destString=UnicodeString::fromUTF8(StringPiece(destArray+labelStart, mappingStart));
504        // Output the previous ASCII labels and process the rest of src in UTF-16.
505        dest.Append(destArray, labelStart);
506        processUnicode(UnicodeString::fromUTF8(StringPiece(src, labelStart)), 0, mappingStart,
507                       isLabel, toASCII,
508                       destString, info, errorCode);
509    } else {
510        // src is too long for the ASCII fastpath implementation.
511        processUnicode(UnicodeString::fromUTF8(src), 0, 0,
512                       isLabel, toASCII,
513                       destString, info, errorCode);
514    }
515    destString.toUTF8(dest);  // calls dest.Flush()
516    if(toASCII && !isLabel) {
517        // length==labelStart==254 means that there is a trailing dot (ok) and
518        // destString is empty (do not index at 253-labelStart).
519        int32_t length=labelStart+destString.length();
520        if( length>=254 && isASCIIString(destString) &&
521            (length>254 ||
522             (labelStart<254 && destString[253-labelStart]!=0x2e))
523        ) {
524            info.errors|=UIDNA_ERROR_DOMAIN_NAME_TOO_LONG;
525        }
526    }
527    if( info.isBiDi && U_SUCCESS(errorCode) && (info.errors&severeErrors)==0 &&
528        (!info.isOkBiDi || (labelStart>0 && !isASCIIOkBiDi(srcArray, labelStart)))
529    ) {
530        info.errors|=UIDNA_ERROR_BIDI;
531    }
532}
533
534UnicodeString &
535UTS46::processUnicode(const UnicodeString &src,
536                      int32_t labelStart, int32_t mappingStart,
537                      UBool isLabel, UBool toASCII,
538                      UnicodeString &dest,
539                      IDNAInfo &info, UErrorCode &errorCode) const {
540    if(mappingStart==0) {
541        uts46Norm2.normalize(src, dest, errorCode);
542    } else {
543        uts46Norm2.normalizeSecondAndAppend(dest, src.tempSubString(mappingStart), errorCode);
544    }
545    if(U_FAILURE(errorCode)) {
546        return dest;
547    }
548    UBool doMapDevChars=
549        toASCII ? (options&UIDNA_NONTRANSITIONAL_TO_ASCII)==0 :
550                  (options&UIDNA_NONTRANSITIONAL_TO_UNICODE)==0;
551    const UChar *destArray=dest.getBuffer();
552    int32_t destLength=dest.length();
553    int32_t labelLimit=labelStart;
554    while(labelLimit<destLength) {
555        UChar c=destArray[labelLimit];
556        if(c==0x2e && !isLabel) {
557            int32_t labelLength=labelLimit-labelStart;
558            int32_t newLength=processLabel(dest, labelStart, labelLength,
559                                            toASCII, info, errorCode);
560            info.errors|=info.labelErrors;
561            info.labelErrors=0;
562            if(U_FAILURE(errorCode)) {
563                return dest;
564            }
565            destArray=dest.getBuffer();
566            destLength+=newLength-labelLength;
567            labelLimit=labelStart+=newLength+1;
568        } else if(0xdf<=c && c<=0x200d && (c==0xdf || c==0x3c2 || c>=0x200c)) {
569            info.isTransDiff=TRUE;
570            if(doMapDevChars) {
571                destLength=mapDevChars(dest, labelStart, labelLimit, errorCode);
572                if(U_FAILURE(errorCode)) {
573                    return dest;
574                }
575                destArray=dest.getBuffer();
576                // Do not increment labelLimit in case c was removed.
577                // All deviation characters have been mapped, no need to check for them again.
578                doMapDevChars=FALSE;
579            } else {
580                ++labelLimit;
581            }
582        } else {
583            ++labelLimit;
584        }
585    }
586    // Permit an empty label at the end (0<labelStart==labelLimit==destLength is ok)
587    // but not an empty label elsewhere nor a completely empty domain name.
588    // processLabel() sets UIDNA_ERROR_EMPTY_LABEL when labelLength==0.
589    if(0==labelStart || labelStart<labelLimit) {
590        processLabel(dest, labelStart, labelLimit-labelStart,
591                      toASCII, info, errorCode);
592        info.errors|=info.labelErrors;
593    }
594    return dest;
595}
596
597int32_t
598UTS46::mapDevChars(UnicodeString &dest, int32_t labelStart, int32_t mappingStart,
599                   UErrorCode &errorCode) const {
600    int32_t length=dest.length();
601    UChar *s=dest.getBuffer(dest[mappingStart]==0xdf ? length+1 : length);
602    if(s==NULL) {
603        errorCode=U_MEMORY_ALLOCATION_ERROR;
604        return length;
605    }
606    int32_t capacity=dest.getCapacity();
607    UBool didMapDevChars=FALSE;
608    int32_t readIndex=mappingStart, writeIndex=mappingStart;
609    do {
610        UChar c=s[readIndex++];
611        switch(c) {
612        case 0xdf:
613            // Map sharp s to ss.
614            didMapDevChars=TRUE;
615            s[writeIndex++]=0x73;  // Replace sharp s with first s.
616            // Insert second s and account for possible buffer reallocation.
617            if(writeIndex==readIndex) {
618                if(length==capacity) {
619                    dest.releaseBuffer(length);
620                    s=dest.getBuffer(length+1);
621                    if(s==NULL) {
622                        errorCode=U_MEMORY_ALLOCATION_ERROR;
623                        return length;
624                    }
625                    capacity=dest.getCapacity();
626                }
627                u_memmove(s+writeIndex+1, s+writeIndex, length-writeIndex);
628                ++readIndex;
629            }
630            s[writeIndex++]=0x73;
631            ++length;
632            break;
633        case 0x3c2:  // Map final sigma to nonfinal sigma.
634            didMapDevChars=TRUE;
635            s[writeIndex++]=0x3c3;
636            break;
637        case 0x200c:  // Ignore/remove ZWNJ.
638        case 0x200d:  // Ignore/remove ZWJ.
639            didMapDevChars=TRUE;
640            --length;
641            break;
642        default:
643            // Only really necessary if writeIndex was different from readIndex.
644            s[writeIndex++]=c;
645            break;
646        }
647    } while(writeIndex<length);
648    dest.releaseBuffer(length);
649    if(didMapDevChars) {
650        // Mapping deviation characters might have resulted in an un-NFC string.
651        // We could use either the NFC or the UTS #46 normalizer.
652        // By using the UTS #46 normalizer again, we avoid having to load a second .nrm data file.
653        UnicodeString normalized;
654        uts46Norm2.normalize(dest.tempSubString(labelStart), normalized, errorCode);
655        if(U_SUCCESS(errorCode)) {
656            dest.replace(labelStart, 0x7fffffff, normalized);
657            return dest.length();
658        }
659    }
660    return length;
661}
662
663// Some non-ASCII characters are equivalent to sequences with
664// non-LDH ASCII characters. To find them:
665// grep disallowed_STD3_valid IdnaMappingTable.txt (or uts46.txt)
666static inline UBool
667isNonASCIIDisallowedSTD3Valid(UChar32 c) {
668    return c==0x2260 || c==0x226E || c==0x226F;
669}
670
671// Replace the label in dest with the label string, if the label was modified.
672// If &label==&dest then the label was modified in-place and labelLength
673// is the new label length, different from label.length().
674// If &label!=&dest then labelLength==label.length().
675// Returns labelLength (= the new label length).
676static int32_t
677replaceLabel(UnicodeString &dest, int32_t destLabelStart, int32_t destLabelLength,
678             const UnicodeString &label, int32_t labelLength) {
679    if(&label!=&dest) {
680        dest.replace(destLabelStart, destLabelLength, label);
681    }
682    return labelLength;
683}
684
685int32_t
686UTS46::processLabel(UnicodeString &dest,
687                    int32_t labelStart, int32_t labelLength,
688                    UBool toASCII,
689                    IDNAInfo &info, UErrorCode &errorCode) const {
690    UnicodeString fromPunycode;
691    UnicodeString *labelString;
692    const UChar *label=dest.getBuffer()+labelStart;
693    int32_t destLabelStart=labelStart;
694    int32_t destLabelLength=labelLength;
695    UBool wasPunycode;
696    if(labelLength>=4 && label[0]==0x78 && label[1]==0x6e && label[2]==0x2d && label[3]==0x2d) {
697        // Label starts with "xn--", try to un-Punycode it.
698        wasPunycode=TRUE;
699        UChar *unicodeBuffer=fromPunycode.getBuffer(-1);  // capacity==-1: most labels should fit
700        if(unicodeBuffer==NULL) {
701            // Should never occur if we used capacity==-1 which uses the internal buffer.
702            errorCode=U_MEMORY_ALLOCATION_ERROR;
703            return labelLength;
704        }
705        UErrorCode punycodeErrorCode=U_ZERO_ERROR;
706        int32_t unicodeLength=u_strFromPunycode(label+4, labelLength-4,
707                                                unicodeBuffer, fromPunycode.getCapacity(),
708                                                NULL, &punycodeErrorCode);
709        if(punycodeErrorCode==U_BUFFER_OVERFLOW_ERROR) {
710            fromPunycode.releaseBuffer(0);
711            unicodeBuffer=fromPunycode.getBuffer(unicodeLength);
712            if(unicodeBuffer==NULL) {
713                errorCode=U_MEMORY_ALLOCATION_ERROR;
714                return labelLength;
715            }
716            punycodeErrorCode=U_ZERO_ERROR;
717            unicodeLength=u_strFromPunycode(label+4, labelLength-4,
718                                            unicodeBuffer, fromPunycode.getCapacity(),
719                                            NULL, &punycodeErrorCode);
720        }
721        fromPunycode.releaseBuffer(unicodeLength);
722        if(U_FAILURE(punycodeErrorCode)) {
723            info.labelErrors|=UIDNA_ERROR_PUNYCODE;
724            return markBadACELabel(dest, labelStart, labelLength, toASCII, info);
725        }
726        // Check for NFC, and for characters that are not
727        // valid or deviation characters according to the normalizer.
728        // If there is something wrong, then the string will change.
729        // Note that the normalizer passes through non-LDH ASCII and deviation characters.
730        // Deviation characters are ok in Punycode even in transitional processing.
731        // In the code further below, if we find non-LDH ASCII and we have UIDNA_USE_STD3_RULES
732        // then we will set UIDNA_ERROR_INVALID_ACE_LABEL there too.
733        UBool isValid=uts46Norm2.isNormalized(fromPunycode, errorCode);
734        if(U_FAILURE(errorCode)) {
735            return labelLength;
736        }
737        if(!isValid) {
738            info.labelErrors|=UIDNA_ERROR_INVALID_ACE_LABEL;
739            return markBadACELabel(dest, labelStart, labelLength, toASCII, info);
740        }
741        labelString=&fromPunycode;
742        label=fromPunycode.getBuffer();
743        labelStart=0;
744        labelLength=fromPunycode.length();
745    } else {
746        wasPunycode=FALSE;
747        labelString=&dest;
748    }
749    // Validity check
750    if(labelLength==0) {
751        if(toASCII) {
752            info.labelErrors|=UIDNA_ERROR_EMPTY_LABEL;
753        }
754        return replaceLabel(dest, destLabelStart, destLabelLength, *labelString, labelLength);
755    }
756    // labelLength>0
757    if(labelLength>=4 && label[2]==0x2d && label[3]==0x2d) {
758        // label starts with "??--"
759        info.labelErrors|=UIDNA_ERROR_HYPHEN_3_4;
760    }
761    if(label[0]==0x2d) {
762        // label starts with "-"
763        info.labelErrors|=UIDNA_ERROR_LEADING_HYPHEN;
764    }
765    if(label[labelLength-1]==0x2d) {
766        // label ends with "-"
767        info.labelErrors|=UIDNA_ERROR_TRAILING_HYPHEN;
768    }
769    // If the label was not a Punycode label, then it was the result of
770    // mapping, normalization and label segmentation.
771    // If the label was in Punycode, then we mapped it again above
772    // and checked its validity.
773    // Now we handle the STD3 restriction to LDH characters (if set)
774    // and we look for U+FFFD which indicates disallowed characters
775    // in a non-Punycode label or U+FFFD itself in a Punycode label.
776    // We also check for dots which can come from the input to a single-label function.
777    // Ok to cast away const because we own the UnicodeString.
778    UChar *s=(UChar *)label;
779    const UChar *limit=label+labelLength;
780    UChar oredChars=0;
781    // If we enforce STD3 rules, then ASCII characters other than LDH and dot are disallowed.
782    UBool disallowNonLDHDot=(options&UIDNA_USE_STD3_RULES)!=0;
783    do {
784        UChar c=*s;
785        if(c<=0x7f) {
786            if(c==0x2e) {
787                info.labelErrors|=UIDNA_ERROR_LABEL_HAS_DOT;
788                *s=0xfffd;
789            } else if(disallowNonLDHDot && asciiData[c]<0) {
790                info.labelErrors|=UIDNA_ERROR_DISALLOWED;
791                *s=0xfffd;
792            }
793        } else {
794            oredChars|=c;
795            if(disallowNonLDHDot && isNonASCIIDisallowedSTD3Valid(c)) {
796                info.labelErrors|=UIDNA_ERROR_DISALLOWED;
797                *s=0xfffd;
798            } else if(c==0xfffd) {
799                info.labelErrors|=UIDNA_ERROR_DISALLOWED;
800            }
801        }
802        ++s;
803    } while(s<limit);
804    // Check for a leading combining mark after other validity checks
805    // so that we don't report UIDNA_ERROR_DISALLOWED for the U+FFFD from here.
806    UChar32 c;
807    int32_t cpLength=0;
808    // "Unsafe" is ok because unpaired surrogates were mapped to U+FFFD.
809    U16_NEXT_UNSAFE(label, cpLength, c);
810    if((U_GET_GC_MASK(c)&U_GC_M_MASK)!=0) {
811        info.labelErrors|=UIDNA_ERROR_LEADING_COMBINING_MARK;
812        labelString->replace(labelStart, cpLength, (UChar)0xfffd);
813        label=labelString->getBuffer()+labelStart;
814        labelLength+=1-cpLength;
815        if(labelString==&dest) {
816            destLabelLength=labelLength;
817        }
818    }
819    if((info.labelErrors&severeErrors)==0) {
820        // Do contextual checks only if we do not have U+FFFD from a severe error
821        // because U+FFFD can make these checks fail.
822        if((options&UIDNA_CHECK_BIDI)!=0 && (!info.isBiDi || info.isOkBiDi)) {
823            checkLabelBiDi(label, labelLength, info);
824        }
825        if( (options&UIDNA_CHECK_CONTEXTJ)!=0 && (oredChars&0x200c)==0x200c &&
826            !isLabelOkContextJ(label, labelLength)
827        ) {
828            info.labelErrors|=UIDNA_ERROR_CONTEXTJ;
829        }
830        if((options&UIDNA_CHECK_CONTEXTO)!=0 && oredChars>=0xb7) {
831            checkLabelContextO(label, labelLength, info);
832        }
833        if(toASCII) {
834            if(wasPunycode) {
835                // Leave a Punycode label unchanged if it has no severe errors.
836                if(destLabelLength>63) {
837                    info.labelErrors|=UIDNA_ERROR_LABEL_TOO_LONG;
838                }
839                return destLabelLength;
840            } else if(oredChars>=0x80) {
841                // Contains non-ASCII characters.
842                UnicodeString punycode;
843                UChar *buffer=punycode.getBuffer(63);  // 63==maximum DNS label length
844                if(buffer==NULL) {
845                    errorCode=U_MEMORY_ALLOCATION_ERROR;
846                    return destLabelLength;
847                }
848                buffer[0]=0x78;  // Write "xn--".
849                buffer[1]=0x6e;
850                buffer[2]=0x2d;
851                buffer[3]=0x2d;
852                int32_t punycodeLength=u_strToPunycode(label, labelLength,
853                                                      buffer+4, punycode.getCapacity()-4,
854                                                      NULL, &errorCode);
855                if(errorCode==U_BUFFER_OVERFLOW_ERROR) {
856                    errorCode=U_ZERO_ERROR;
857                    punycode.releaseBuffer(4);
858                    buffer=punycode.getBuffer(4+punycodeLength);
859                    if(buffer==NULL) {
860                        errorCode=U_MEMORY_ALLOCATION_ERROR;
861                        return destLabelLength;
862                    }
863                    punycodeLength=u_strToPunycode(label, labelLength,
864                                                  buffer+4, punycode.getCapacity()-4,
865                                                  NULL, &errorCode);
866                }
867                punycodeLength+=4;
868                punycode.releaseBuffer(punycodeLength);
869                if(U_FAILURE(errorCode)) {
870                    return destLabelLength;
871                }
872                if(punycodeLength>63) {
873                    info.labelErrors|=UIDNA_ERROR_LABEL_TOO_LONG;
874                }
875                return replaceLabel(dest, destLabelStart, destLabelLength,
876                                    punycode, punycodeLength);
877            } else {
878                // all-ASCII label
879                if(labelLength>63) {
880                    info.labelErrors|=UIDNA_ERROR_LABEL_TOO_LONG;
881                }
882            }
883        }
884    } else {
885        // If a Punycode label has severe errors,
886        // then leave it but make sure it does not look valid.
887        if(wasPunycode) {
888            info.labelErrors|=UIDNA_ERROR_INVALID_ACE_LABEL;
889            return markBadACELabel(dest, destLabelStart, destLabelLength, toASCII, info);
890        }
891    }
892    return replaceLabel(dest, destLabelStart, destLabelLength, *labelString, labelLength);
893}
894
895// Make sure an ACE label does not look valid.
896// Append U+FFFD if the label has only LDH characters.
897// If UIDNA_USE_STD3_RULES, also replace disallowed ASCII characters with U+FFFD.
898int32_t
899UTS46::markBadACELabel(UnicodeString &dest,
900                       int32_t labelStart, int32_t labelLength,
901                       UBool toASCII, IDNAInfo &info) const {
902    UBool disallowNonLDHDot=(options&UIDNA_USE_STD3_RULES)!=0;
903    UBool isASCII=TRUE;
904    UBool onlyLDH=TRUE;
905    const UChar *label=dest.getBuffer()+labelStart;
906    // Ok to cast away const because we own the UnicodeString.
907    UChar *s=(UChar *)label+4;  // After the initial "xn--".
908    const UChar *limit=label+labelLength;
909    do {
910        UChar c=*s;
911        if(c<=0x7f) {
912            if(c==0x2e) {
913                info.labelErrors|=UIDNA_ERROR_LABEL_HAS_DOT;
914                *s=0xfffd;
915                isASCII=onlyLDH=FALSE;
916            } else if(asciiData[c]<0) {
917                onlyLDH=FALSE;
918                if(disallowNonLDHDot) {
919                    *s=0xfffd;
920                    isASCII=FALSE;
921                }
922            }
923        } else {
924            isASCII=onlyLDH=FALSE;
925        }
926    } while(++s<limit);
927    if(onlyLDH) {
928        dest.insert(labelStart+labelLength, (UChar)0xfffd);
929        ++labelLength;
930    } else {
931        if(toASCII && isASCII && labelLength>63) {
932            info.labelErrors|=UIDNA_ERROR_LABEL_TOO_LONG;
933        }
934    }
935    return labelLength;
936}
937
938const uint32_t L_MASK=U_MASK(U_LEFT_TO_RIGHT);
939const uint32_t R_AL_MASK=U_MASK(U_RIGHT_TO_LEFT)|U_MASK(U_RIGHT_TO_LEFT_ARABIC);
940const uint32_t L_R_AL_MASK=L_MASK|R_AL_MASK;
941
942const uint32_t R_AL_AN_MASK=R_AL_MASK|U_MASK(U_ARABIC_NUMBER);
943
944const uint32_t EN_AN_MASK=U_MASK(U_EUROPEAN_NUMBER)|U_MASK(U_ARABIC_NUMBER);
945const uint32_t R_AL_EN_AN_MASK=R_AL_MASK|EN_AN_MASK;
946const uint32_t L_EN_MASK=L_MASK|U_MASK(U_EUROPEAN_NUMBER);
947
948const uint32_t ES_CS_ET_ON_BN_NSM_MASK=
949    U_MASK(U_EUROPEAN_NUMBER_SEPARATOR)|
950    U_MASK(U_COMMON_NUMBER_SEPARATOR)|
951    U_MASK(U_EUROPEAN_NUMBER_TERMINATOR)|
952    U_MASK(U_OTHER_NEUTRAL)|
953    U_MASK(U_BOUNDARY_NEUTRAL)|
954    U_MASK(U_DIR_NON_SPACING_MARK);
955const uint32_t L_EN_ES_CS_ET_ON_BN_NSM_MASK=L_EN_MASK|ES_CS_ET_ON_BN_NSM_MASK;
956const 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;
957
958// We scan the whole label and check both for whether it contains RTL characters
959// and whether it passes the BiDi Rule.
960// In a BiDi domain name, all labels must pass the BiDi Rule, but we might find
961// that a domain name is a BiDi domain name (has an RTL label) only after
962// processing several earlier labels.
963void
964UTS46::checkLabelBiDi(const UChar *label, int32_t labelLength, IDNAInfo &info) const {
965    // IDNA2008 BiDi rule
966    // Get the directionality of the first character.
967    UChar32 c;
968    int32_t i=0;
969    U16_NEXT_UNSAFE(label, i, c);
970    uint32_t firstMask=U_MASK(u_charDirection(c));
971    // 1. The first character must be a character with BIDI property L, R
972    // or AL.  If it has the R or AL property, it is an RTL label; if it
973    // has the L property, it is an LTR label.
974    if((firstMask&~L_R_AL_MASK)!=0) {
975        info.isOkBiDi=FALSE;
976    }
977    // Get the directionality of the last non-NSM character.
978    uint32_t lastMask;
979    for(;;) {
980        if(i>=labelLength) {
981            lastMask=firstMask;
982            break;
983        }
984        U16_PREV_UNSAFE(label, labelLength, c);
985        UCharDirection dir=u_charDirection(c);
986        if(dir!=U_DIR_NON_SPACING_MARK) {
987            lastMask=U_MASK(dir);
988            break;
989        }
990    }
991    // 3. In an RTL label, the end of the label must be a character with
992    // BIDI property R, AL, EN or AN, followed by zero or more
993    // characters with BIDI property NSM.
994    // 6. In an LTR label, the end of the label must be a character with
995    // BIDI property L or EN, followed by zero or more characters with
996    // BIDI property NSM.
997    if( (firstMask&L_MASK)!=0 ?
998            (lastMask&~L_EN_MASK)!=0 :
999            (lastMask&~R_AL_EN_AN_MASK)!=0
1000    ) {
1001        info.isOkBiDi=FALSE;
1002    }
1003    // Get the directionalities of the intervening characters.
1004    uint32_t mask=0;
1005    while(i<labelLength) {
1006        U16_NEXT_UNSAFE(label, i, c);
1007        mask|=U_MASK(u_charDirection(c));
1008    }
1009    if(firstMask&L_MASK) {
1010        // 5. In an LTR label, only characters with the BIDI properties L, EN,
1011        // ES, CS, ET, ON, BN and NSM are allowed.
1012        if((mask&~L_EN_ES_CS_ET_ON_BN_NSM_MASK)!=0) {
1013            info.isOkBiDi=FALSE;
1014        }
1015    } else {
1016        // 2. In an RTL label, only characters with the BIDI properties R, AL,
1017        // AN, EN, ES, CS, ET, ON, BN and NSM are allowed.
1018        if((mask&~R_AL_AN_EN_ES_CS_ET_ON_BN_NSM_MASK)!=0) {
1019            info.isOkBiDi=FALSE;
1020        }
1021        // 4. In an RTL label, if an EN is present, no AN may be present, and
1022        // vice versa.
1023        if((mask&EN_AN_MASK)==EN_AN_MASK) {
1024            info.isOkBiDi=FALSE;
1025        }
1026    }
1027    // An RTL label is a label that contains at least one character of type
1028    // R, AL or AN. [...]
1029    // A "BIDI domain name" is a domain name that contains at least one RTL
1030    // label. [...]
1031    // The following rule, consisting of six conditions, applies to labels
1032    // in BIDI domain names.
1033    if(((firstMask|mask|lastMask)&R_AL_AN_MASK)!=0) {
1034        info.isBiDi=TRUE;
1035    }
1036}
1037
1038// Special code for the ASCII prefix of a BiDi domain name.
1039// The ASCII prefix is all-LTR.
1040
1041// IDNA2008 BiDi rule, parts relevant to ASCII labels:
1042// 1. The first character must be a character with BIDI property L [...]
1043// 5. In an LTR label, only characters with the BIDI properties L, EN,
1044// ES, CS, ET, ON, BN and NSM are allowed.
1045// 6. In an LTR label, the end of the label must be a character with
1046// BIDI property L or EN [...]
1047
1048// UTF-16 version, called for mapped ASCII prefix.
1049// Cannot contain uppercase A-Z.
1050// s[length-1] must be the trailing dot.
1051static UBool
1052isASCIIOkBiDi(const UChar *s, int32_t length) {
1053    int32_t labelStart=0;
1054    for(int32_t i=0; i<length; ++i) {
1055        UChar c=s[i];
1056        if(c==0x2e) {  // dot
1057            if(i>labelStart) {
1058                c=s[i-1];
1059                if(!(0x61<=c && c<=0x7a) && !(0x30<=c && c<=0x39)) {
1060                    // Last character in the label is not an L or EN.
1061                    return FALSE;
1062                }
1063            }
1064            labelStart=i+1;
1065        } else if(i==labelStart) {
1066            if(!(0x61<=c && c<=0x7a)) {
1067                // First character in the label is not an L.
1068                return FALSE;
1069            }
1070        } else {
1071            if(c<=0x20 && (c>=0x1c || (9<=c && c<=0xd))) {
1072                // Intermediate character in the label is a B, S or WS.
1073                return FALSE;
1074            }
1075        }
1076    }
1077    return TRUE;
1078}
1079
1080// UTF-8 version, called for source ASCII prefix.
1081// Can contain uppercase A-Z.
1082// s[length-1] must be the trailing dot.
1083static UBool
1084isASCIIOkBiDi(const char *s, int32_t length) {
1085    int32_t labelStart=0;
1086    for(int32_t i=0; i<length; ++i) {
1087        char c=s[i];
1088        if(c==0x2e) {  // dot
1089            if(i>labelStart) {
1090                c=s[i-1];
1091                if(!(0x61<=c && c<=0x7a) && !(0x41<=c && c<=0x5a) && !(0x30<=c && c<=0x39)) {
1092                    // Last character in the label is not an L or EN.
1093                    return FALSE;
1094                }
1095            }
1096            labelStart=i+1;
1097        } else if(i==labelStart) {
1098            if(!(0x61<=c && c<=0x7a) && !(0x41<=c && c<=0x5a)) {
1099                // First character in the label is not an L.
1100                return FALSE;
1101            }
1102        } else {
1103            if(c<=0x20 && (c>=0x1c || (9<=c && c<=0xd))) {
1104                // Intermediate character in the label is a B, S or WS.
1105                return FALSE;
1106            }
1107        }
1108    }
1109    return TRUE;
1110}
1111
1112UBool
1113UTS46::isLabelOkContextJ(const UChar *label, int32_t labelLength) const {
1114    const UBiDiProps *bdp=ubidi_getSingleton();
1115    // [IDNA2008-Tables]
1116    // 200C..200D  ; CONTEXTJ    # ZERO WIDTH NON-JOINER..ZERO WIDTH JOINER
1117    for(int32_t i=0; i<labelLength; ++i) {
1118        if(label[i]==0x200c) {
1119            // Appendix A.1. ZERO WIDTH NON-JOINER
1120            // Rule Set:
1121            //  False;
1122            //  If Canonical_Combining_Class(Before(cp)) .eq.  Virama Then True;
1123            //  If RegExpMatch((Joining_Type:{L,D})(Joining_Type:T)*\u200C
1124            //     (Joining_Type:T)*(Joining_Type:{R,D})) Then True;
1125            if(i==0) {
1126                return FALSE;
1127            }
1128            UChar32 c;
1129            int32_t j=i;
1130            U16_PREV_UNSAFE(label, j, c);
1131            if(uts46Norm2.getCombiningClass(c)==9) {
1132                continue;
1133            }
1134            // check precontext (Joining_Type:{L,D})(Joining_Type:T)*
1135            for(;;) {
1136                UJoiningType type=ubidi_getJoiningType(bdp, c);
1137                if(type==U_JT_TRANSPARENT) {
1138                    if(j==0) {
1139                        return FALSE;
1140                    }
1141                    U16_PREV_UNSAFE(label, j, c);
1142                } else if(type==U_JT_LEFT_JOINING || type==U_JT_DUAL_JOINING) {
1143                    break;  // precontext fulfilled
1144                } else {
1145                    return FALSE;
1146                }
1147            }
1148            // check postcontext (Joining_Type:T)*(Joining_Type:{R,D})
1149            for(j=i+1;;) {
1150                if(j==labelLength) {
1151                    return FALSE;
1152                }
1153                U16_NEXT_UNSAFE(label, j, c);
1154                UJoiningType type=ubidi_getJoiningType(bdp, c);
1155                if(type==U_JT_TRANSPARENT) {
1156                    // just skip this character
1157                } else if(type==U_JT_RIGHT_JOINING || type==U_JT_DUAL_JOINING) {
1158                    break;  // postcontext fulfilled
1159                } else {
1160                    return FALSE;
1161                }
1162            }
1163        } else if(label[i]==0x200d) {
1164            // Appendix A.2. ZERO WIDTH JOINER (U+200D)
1165            // Rule Set:
1166            //  False;
1167            //  If Canonical_Combining_Class(Before(cp)) .eq.  Virama Then True;
1168            if(i==0) {
1169                return FALSE;
1170            }
1171            UChar32 c;
1172            int32_t j=i;
1173            U16_PREV_UNSAFE(label, j, c);
1174            if(uts46Norm2.getCombiningClass(c)!=9) {
1175                return FALSE;
1176            }
1177        }
1178    }
1179    return TRUE;
1180}
1181
1182void
1183UTS46::checkLabelContextO(const UChar *label, int32_t labelLength, IDNAInfo &info) const {
1184    int32_t labelEnd=labelLength-1;  // inclusive
1185    int32_t arabicDigits=0;  // -1 for 066x, +1 for 06Fx
1186    for(int32_t i=0; i<=labelEnd; ++i) {
1187        UChar32 c=label[i];
1188        if(c<0xb7) {
1189            // ASCII fastpath
1190        } else if(c<=0x6f9) {
1191            if(c==0xb7) {
1192                // Appendix A.3. MIDDLE DOT (U+00B7)
1193                // Rule Set:
1194                //  False;
1195                //  If Before(cp) .eq.  U+006C And
1196                //     After(cp) .eq.  U+006C Then True;
1197                if(!(0<i && label[i-1]==0x6c &&
1198                     i<labelEnd && label[i+1]==0x6c)) {
1199                    info.labelErrors|=UIDNA_ERROR_CONTEXTO_PUNCTUATION;
1200                }
1201            } else if(c==0x375) {
1202                // Appendix A.4. GREEK LOWER NUMERAL SIGN (KERAIA) (U+0375)
1203                // Rule Set:
1204                //  False;
1205                //  If Script(After(cp)) .eq.  Greek Then True;
1206                UScriptCode script=USCRIPT_INVALID_CODE;
1207                if(i<labelEnd) {
1208                    UErrorCode errorCode=U_ZERO_ERROR;
1209                    int32_t j=i+1;
1210                    U16_NEXT(label, j, labelLength, c);
1211                    script=uscript_getScript(c, &errorCode);
1212                }
1213                if(script!=USCRIPT_GREEK) {
1214                    info.labelErrors|=UIDNA_ERROR_CONTEXTO_PUNCTUATION;
1215                }
1216            } else if(c==0x5f3 || c==0x5f4) {
1217                // Appendix A.5. HEBREW PUNCTUATION GERESH (U+05F3)
1218                // Rule Set:
1219                //  False;
1220                //  If Script(Before(cp)) .eq.  Hebrew Then True;
1221                //
1222                // Appendix A.6. HEBREW PUNCTUATION GERSHAYIM (U+05F4)
1223                // Rule Set:
1224                //  False;
1225                //  If Script(Before(cp)) .eq.  Hebrew Then True;
1226                UScriptCode script=USCRIPT_INVALID_CODE;
1227                if(0<i) {
1228                    UErrorCode errorCode=U_ZERO_ERROR;
1229                    int32_t j=i;
1230                    U16_PREV(label, 0, j, c);
1231                    script=uscript_getScript(c, &errorCode);
1232                }
1233                if(script!=USCRIPT_HEBREW) {
1234                    info.labelErrors|=UIDNA_ERROR_CONTEXTO_PUNCTUATION;
1235                }
1236            } else if(0x660<=c /* && c<=0x6f9 */) {
1237                // Appendix A.8. ARABIC-INDIC DIGITS (0660..0669)
1238                // Rule Set:
1239                //  True;
1240                //  For All Characters:
1241                //    If cp .in. 06F0..06F9 Then False;
1242                //  End For;
1243                //
1244                // Appendix A.9. EXTENDED ARABIC-INDIC DIGITS (06F0..06F9)
1245                // Rule Set:
1246                //  True;
1247                //  For All Characters:
1248                //    If cp .in. 0660..0669 Then False;
1249                //  End For;
1250                if(c<=0x669) {
1251                    if(arabicDigits>0) {
1252                        info.labelErrors|=UIDNA_ERROR_CONTEXTO_DIGITS;
1253                    }
1254                    arabicDigits=-1;
1255                } else if(0x6f0<=c) {
1256                    if(arabicDigits<0) {
1257                        info.labelErrors|=UIDNA_ERROR_CONTEXTO_DIGITS;
1258                    }
1259                    arabicDigits=1;
1260                }
1261            }
1262        } else if(c==0x30fb) {
1263            // Appendix A.7. KATAKANA MIDDLE DOT (U+30FB)
1264            // Rule Set:
1265            //  False;
1266            //  For All Characters:
1267            //    If Script(cp) .in. {Hiragana, Katakana, Han} Then True;
1268            //  End For;
1269            UErrorCode errorCode=U_ZERO_ERROR;
1270            for(int j=0;;) {
1271                if(j>labelEnd) {
1272                    info.labelErrors|=UIDNA_ERROR_CONTEXTO_PUNCTUATION;
1273                    break;
1274                }
1275                U16_NEXT(label, j, labelLength, c);
1276                UScriptCode script=uscript_getScript(c, &errorCode);
1277                if(script==USCRIPT_HIRAGANA || script==USCRIPT_KATAKANA || script==USCRIPT_HAN) {
1278                    break;
1279                }
1280            }
1281        }
1282    }
1283}
1284
1285U_NAMESPACE_END
1286
1287// C API ------------------------------------------------------------------- ***
1288
1289U_NAMESPACE_USE
1290
1291U_CAPI UIDNA * U_EXPORT2
1292uidna_openUTS46(uint32_t options, UErrorCode *pErrorCode) {
1293    return reinterpret_cast<UIDNA *>(IDNA::createUTS46Instance(options, *pErrorCode));
1294}
1295
1296U_CAPI void U_EXPORT2
1297uidna_close(UIDNA *idna) {
1298    delete reinterpret_cast<IDNA *>(idna);
1299}
1300
1301static UBool
1302checkArgs(const void *label, int32_t length,
1303          void *dest, int32_t capacity,
1304          UIDNAInfo *pInfo, UErrorCode *pErrorCode) {
1305    if(U_FAILURE(*pErrorCode)) {
1306        return FALSE;
1307    }
1308    // sizeof(UIDNAInfo)=16 in the first API version.
1309    if(pInfo==NULL || pInfo->size<16) {
1310        *pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
1311        return FALSE;
1312    }
1313    if( (label==NULL ? length!=0 : length<-1) ||
1314        (dest==NULL ? capacity!=0 : capacity<0) ||
1315        (dest==label && label!=NULL)
1316    ) {
1317        *pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
1318        return FALSE;
1319    }
1320    // Set all *pInfo bytes to 0 except for the size field itself.
1321    uprv_memset(&pInfo->size+1, 0, pInfo->size-sizeof(pInfo->size));
1322    return TRUE;
1323}
1324
1325static void
1326idnaInfoToStruct(IDNAInfo &info, UIDNAInfo *pInfo) {
1327    pInfo->isTransitionalDifferent=info.isTransitionalDifferent();
1328    pInfo->errors=info.getErrors();
1329}
1330
1331U_CAPI int32_t U_EXPORT2
1332uidna_labelToASCII(const UIDNA *idna,
1333                   const UChar *label, int32_t length,
1334                   UChar *dest, int32_t capacity,
1335                   UIDNAInfo *pInfo, UErrorCode *pErrorCode) {
1336    if(!checkArgs(label, length, dest, capacity, pInfo, pErrorCode)) {
1337        return 0;
1338    }
1339    UnicodeString src((UBool)(length<0), label, length);
1340    UnicodeString destString(dest, 0, capacity);
1341    IDNAInfo info;
1342    reinterpret_cast<const IDNA *>(idna)->labelToASCII(src, destString, info, *pErrorCode);
1343    idnaInfoToStruct(info, pInfo);
1344    return destString.extract(dest, capacity, *pErrorCode);
1345}
1346
1347U_CAPI int32_t U_EXPORT2
1348uidna_labelToUnicode(const UIDNA *idna,
1349                     const UChar *label, int32_t length,
1350                     UChar *dest, int32_t capacity,
1351                     UIDNAInfo *pInfo, UErrorCode *pErrorCode) {
1352    if(!checkArgs(label, length, dest, capacity, pInfo, pErrorCode)) {
1353        return 0;
1354    }
1355    UnicodeString src((UBool)(length<0), label, length);
1356    UnicodeString destString(dest, 0, capacity);
1357    IDNAInfo info;
1358    reinterpret_cast<const IDNA *>(idna)->labelToUnicode(src, destString, info, *pErrorCode);
1359    idnaInfoToStruct(info, pInfo);
1360    return destString.extract(dest, capacity, *pErrorCode);
1361}
1362
1363U_CAPI int32_t U_EXPORT2
1364uidna_nameToASCII(const UIDNA *idna,
1365                  const UChar *name, int32_t length,
1366                  UChar *dest, int32_t capacity,
1367                  UIDNAInfo *pInfo, UErrorCode *pErrorCode) {
1368    if(!checkArgs(name, length, dest, capacity, pInfo, pErrorCode)) {
1369        return 0;
1370    }
1371    UnicodeString src((UBool)(length<0), name, length);
1372    UnicodeString destString(dest, 0, capacity);
1373    IDNAInfo info;
1374    reinterpret_cast<const IDNA *>(idna)->nameToASCII(src, destString, info, *pErrorCode);
1375    idnaInfoToStruct(info, pInfo);
1376    return destString.extract(dest, capacity, *pErrorCode);
1377}
1378
1379U_CAPI int32_t U_EXPORT2
1380uidna_nameToUnicode(const UIDNA *idna,
1381                    const UChar *name, int32_t length,
1382                    UChar *dest, int32_t capacity,
1383                    UIDNAInfo *pInfo, UErrorCode *pErrorCode) {
1384    if(!checkArgs(name, length, dest, capacity, pInfo, pErrorCode)) {
1385        return 0;
1386    }
1387    UnicodeString src((UBool)(length<0), name, length);
1388    UnicodeString destString(dest, 0, capacity);
1389    IDNAInfo info;
1390    reinterpret_cast<const IDNA *>(idna)->nameToUnicode(src, destString, info, *pErrorCode);
1391    idnaInfoToStruct(info, pInfo);
1392    return destString.extract(dest, capacity, *pErrorCode);
1393}
1394
1395U_CAPI int32_t U_EXPORT2
1396uidna_labelToASCII_UTF8(const UIDNA *idna,
1397                        const char *label, int32_t length,
1398                        char *dest, int32_t capacity,
1399                        UIDNAInfo *pInfo, UErrorCode *pErrorCode) {
1400    if(!checkArgs(label, length, dest, capacity, pInfo, pErrorCode)) {
1401        return 0;
1402    }
1403    StringPiece src(label, length<0 ? uprv_strlen(label) : length);
1404    CheckedArrayByteSink sink(dest, capacity);
1405    IDNAInfo info;
1406    reinterpret_cast<const IDNA *>(idna)->labelToASCII_UTF8(src, sink, info, *pErrorCode);
1407    idnaInfoToStruct(info, pInfo);
1408    return u_terminateChars(dest, capacity, sink.NumberOfBytesAppended(), pErrorCode);
1409}
1410
1411U_CAPI int32_t U_EXPORT2
1412uidna_labelToUnicodeUTF8(const UIDNA *idna,
1413                         const char *label, int32_t length,
1414                         char *dest, int32_t capacity,
1415                         UIDNAInfo *pInfo, UErrorCode *pErrorCode) {
1416    if(!checkArgs(label, length, dest, capacity, pInfo, pErrorCode)) {
1417        return 0;
1418    }
1419    StringPiece src(label, length<0 ? uprv_strlen(label) : length);
1420    CheckedArrayByteSink sink(dest, capacity);
1421    IDNAInfo info;
1422    reinterpret_cast<const IDNA *>(idna)->labelToUnicodeUTF8(src, sink, info, *pErrorCode);
1423    idnaInfoToStruct(info, pInfo);
1424    return u_terminateChars(dest, capacity, sink.NumberOfBytesAppended(), pErrorCode);
1425}
1426
1427U_CAPI int32_t U_EXPORT2
1428uidna_nameToASCII_UTF8(const UIDNA *idna,
1429                       const char *name, int32_t length,
1430                       char *dest, int32_t capacity,
1431                       UIDNAInfo *pInfo, UErrorCode *pErrorCode) {
1432    if(!checkArgs(name, length, dest, capacity, pInfo, pErrorCode)) {
1433        return 0;
1434    }
1435    StringPiece src(name, length<0 ? uprv_strlen(name) : length);
1436    CheckedArrayByteSink sink(dest, capacity);
1437    IDNAInfo info;
1438    reinterpret_cast<const IDNA *>(idna)->nameToASCII_UTF8(src, sink, info, *pErrorCode);
1439    idnaInfoToStruct(info, pInfo);
1440    return u_terminateChars(dest, capacity, sink.NumberOfBytesAppended(), pErrorCode);
1441}
1442
1443U_CAPI int32_t U_EXPORT2
1444uidna_nameToUnicodeUTF8(const UIDNA *idna,
1445                        const char *name, int32_t length,
1446                        char *dest, int32_t capacity,
1447                        UIDNAInfo *pInfo, UErrorCode *pErrorCode) {
1448    if(!checkArgs(name, length, dest, capacity, pInfo, pErrorCode)) {
1449        return 0;
1450    }
1451    StringPiece src(name, length<0 ? uprv_strlen(name) : length);
1452    CheckedArrayByteSink sink(dest, capacity);
1453    IDNAInfo info;
1454    reinterpret_cast<const IDNA *>(idna)->nameToUnicodeUTF8(src, sink, info, *pErrorCode);
1455    idnaInfoToStruct(info, pInfo);
1456    return u_terminateChars(dest, capacity, sink.NumberOfBytesAppended(), pErrorCode);
1457}
1458
1459#endif  // UCONFIG_NO_IDNA
1460