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      1 // Copyright (C) 2016 and later: Unicode, Inc. and others.
      2 // License & terms of use: http://www.unicode.org/copyright.html
      3 /*
      4 **********************************************************************
      5 *   Copyright (C) 2001-2011, International Business Machines
      6 *   Corporation and others.  All Rights Reserved.
      7 **********************************************************************
      8 *   Date        Name        Description
      9 *   07/03/01    aliu        Creation.
     10 **********************************************************************
     11 */
     12 
     13 #include "unicode/utypes.h"
     14 
     15 #if !UCONFIG_NO_TRANSLITERATION
     16 
     17 #include "unicode/normalizer2.h"
     18 #include "unicode/utf16.h"
     19 #include "cstring.h"
     20 #include "nortrans.h"
     21 
     22 U_NAMESPACE_BEGIN
     23 
     24 UOBJECT_DEFINE_RTTI_IMPLEMENTATION(NormalizationTransliterator)
     25 
     26 static inline Transliterator::Token cstrToken(const char *s) {
     27     return Transliterator::pointerToken((void *)s);
     28 }
     29 
     30 /**
     31  * System registration hook.
     32  */
     33 void NormalizationTransliterator::registerIDs() {
     34     // In the Token, the byte after the NUL is the UNormalization2Mode.
     35     Transliterator::_registerFactory(UNICODE_STRING_SIMPLE("Any-NFC"),
     36                                      _create, cstrToken("nfc\0\0"));
     37     Transliterator::_registerFactory(UNICODE_STRING_SIMPLE("Any-NFKC"),
     38                                      _create, cstrToken("nfkc\0\0"));
     39     Transliterator::_registerFactory(UNICODE_STRING_SIMPLE("Any-NFD"),
     40                                      _create, cstrToken("nfc\0\1"));
     41     Transliterator::_registerFactory(UNICODE_STRING_SIMPLE("Any-NFKD"),
     42                                      _create, cstrToken("nfkc\0\1"));
     43     Transliterator::_registerFactory(UNICODE_STRING_SIMPLE("Any-FCD"),
     44                                      _create, cstrToken("nfc\0\2"));
     45     Transliterator::_registerFactory(UNICODE_STRING_SIMPLE("Any-FCC"),
     46                                      _create, cstrToken("nfc\0\3"));
     47     Transliterator::_registerSpecialInverse(UNICODE_STRING_SIMPLE("NFC"),
     48                                             UNICODE_STRING_SIMPLE("NFD"), TRUE);
     49     Transliterator::_registerSpecialInverse(UNICODE_STRING_SIMPLE("NFKC"),
     50                                             UNICODE_STRING_SIMPLE("NFKD"), TRUE);
     51     Transliterator::_registerSpecialInverse(UNICODE_STRING_SIMPLE("FCC"),
     52                                             UNICODE_STRING_SIMPLE("NFD"), FALSE);
     53     Transliterator::_registerSpecialInverse(UNICODE_STRING_SIMPLE("FCD"),
     54                                             UNICODE_STRING_SIMPLE("FCD"), FALSE);
     55 }
     56 
     57 /**
     58  * Factory methods
     59  */
     60 Transliterator* NormalizationTransliterator::_create(const UnicodeString& ID,
     61                                                      Token context) {
     62     const char *name = (const char *)context.pointer;
     63     UNormalization2Mode mode = (UNormalization2Mode)uprv_strchr(name, 0)[1];
     64     UErrorCode errorCode = U_ZERO_ERROR;
     65     const Normalizer2 *norm2 = Normalizer2::getInstance(NULL, name, mode, errorCode);
     66     if(U_SUCCESS(errorCode)) {
     67         return new NormalizationTransliterator(ID, *norm2);
     68     } else {
     69         return NULL;
     70     }
     71 }
     72 
     73 /**
     74  * Constructs a transliterator.
     75  */
     76 NormalizationTransliterator::NormalizationTransliterator(const UnicodeString& id,
     77                                                          const Normalizer2 &norm2) :
     78     Transliterator(id, 0), fNorm2(norm2) {}
     79 
     80 /**
     81  * Destructor.
     82  */
     83 NormalizationTransliterator::~NormalizationTransliterator() {
     84 }
     85 
     86 /**
     87  * Copy constructor.
     88  */
     89 NormalizationTransliterator::NormalizationTransliterator(const NormalizationTransliterator& o) :
     90     Transliterator(o), fNorm2(o.fNorm2) {}
     91 
     92 /**
     93  * Transliterator API.
     94  */
     95 Transliterator* NormalizationTransliterator::clone(void) const {
     96     return new NormalizationTransliterator(*this);
     97 }
     98 
     99 /**
    100  * Implements {@link Transliterator#handleTransliterate}.
    101  */
    102 void NormalizationTransliterator::handleTransliterate(Replaceable& text, UTransPosition& offsets,
    103                                                       UBool isIncremental) const {
    104     // start and limit of the input range
    105     int32_t start = offsets.start;
    106     int32_t limit = offsets.limit;
    107     if(start >= limit) {
    108         return;
    109     }
    110 
    111     /*
    112      * Normalize as short chunks at a time as possible even in
    113      * bulk mode, so that styled text is minimally disrupted.
    114      * In incremental mode, a chunk that ends with offsets.limit
    115      * must not be normalized.
    116      *
    117      * If it was known that the input text is not styled, then
    118      * a bulk mode normalization could look like this:
    119 
    120     UnicodeString input, normalized;
    121     int32_t length = limit - start;
    122     _Replaceable_extractBetween(text, start, limit, input.getBuffer(length));
    123     input.releaseBuffer(length);
    124 
    125     UErrorCode status = U_ZERO_ERROR;
    126     fNorm2.normalize(input, normalized, status);
    127 
    128     text.handleReplaceBetween(start, limit, normalized);
    129 
    130     int32_t delta = normalized.length() - length;
    131     offsets.contextLimit += delta;
    132     offsets.limit += delta;
    133     offsets.start = limit + delta;
    134 
    135      */
    136     UErrorCode errorCode = U_ZERO_ERROR;
    137     UnicodeString segment;
    138     UnicodeString normalized;
    139     UChar32 c = text.char32At(start);
    140     do {
    141         int32_t prev = start;
    142         // Skip at least one character so we make progress.
    143         // c holds the character at start.
    144         segment.remove();
    145         do {
    146             segment.append(c);
    147             start += U16_LENGTH(c);
    148         } while(start < limit && !fNorm2.hasBoundaryBefore(c = text.char32At(start)));
    149         if(start == limit && isIncremental && !fNorm2.hasBoundaryAfter(c)) {
    150             // stop in incremental mode when we reach the input limit
    151             // in case there are additional characters that could change the
    152             // normalization result
    153             start=prev;
    154             break;
    155         }
    156         fNorm2.normalize(segment, normalized, errorCode);
    157         if(U_FAILURE(errorCode)) {
    158             break;
    159         }
    160         if(segment != normalized) {
    161             // replace the input chunk with its normalized form
    162             text.handleReplaceBetween(prev, start, normalized);
    163 
    164             // update all necessary indexes accordingly
    165             int32_t delta = normalized.length() - (start - prev);
    166             start += delta;
    167             limit += delta;
    168         }
    169     } while(start < limit);
    170 
    171     offsets.start = start;
    172     offsets.contextLimit += limit - offsets.limit;
    173     offsets.limit = limit;
    174 }
    175 
    176 U_NAMESPACE_END
    177 
    178 #endif /* #if !UCONFIG_NO_TRANSLITERATION */
    179