icuSources/i18n/titletrn.cpp

   1 // © 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 *   05/24/01    aliu        Creation.
  10 **********************************************************************
  11 */
  12
  13 #include "unicode/utypes.h"
  14
  15 #if !UCONFIG_NO_TRANSLITERATION
  16
  17 #include "unicode/uchar.h"
  18 #include "unicode/uniset.h"
  19 #include "unicode/ustring.h"
  20 #include "unicode/utf16.h"
  21 #include "titletrn.h"
  22 #include "umutex.h"
  23 #include "ucase.h"
  24 #include "cpputils.h"
  25
  26 U_NAMESPACE_BEGIN
  27
  28 UOBJECT_DEFINE_RTTI_IMPLEMENTATION(TitlecaseTransliterator)
  29
  30 TitlecaseTransliterator::TitlecaseTransliterator() :
  31     CaseMapTransliterator(UNICODE_STRING("Any-Title", 9), NULL)
  32 {
  33     // Need to look back 2 characters in the case of "can't"
  34     setMaximumContextLength(2);
  35 }
  36
  37 /**
  38  * Destructor.
  39  */
  40 TitlecaseTransliterator::~TitlecaseTransliterator() {
  41 }
  42
  43 /**
  44  * Copy constructor.
  45  */
  46 TitlecaseTransliterator::TitlecaseTransliterator(const TitlecaseTransliterator& o) :
  47     CaseMapTransliterator(o)
  48 {
  49 }
  50
  51 /**
  52  * Assignment operator.
  53  */
  54 /*TitlecaseTransliterator& TitlecaseTransliterator::operator=(
  55                              const TitlecaseTransliterator& o) {
  56     CaseMapTransliterator::operator=(o);
  57     return *this;
  58 }*/
  59
  60 /**
  61  * Transliterator API.
  62  */
  63 Transliterator* TitlecaseTransliterator::clone(void) const {
  64     return new TitlecaseTransliterator(*this);
  65 }
  66
  67 /**
  68  * Implements {@link Transliterator#handleTransliterate}.
  69  */
  70 void TitlecaseTransliterator::handleTransliterate(
  71                                   Replaceable& text, UTransPosition& offsets,
  72                                   UBool isIncremental) const
  73 {
  74     // TODO reimplement, see ustrcase.c
  75     // using a real word break iterator
  76     //   instead of just looking for a transition between cased and uncased characters
  77     // call CaseMapTransliterator::handleTransliterate() for lowercasing? (set fMap)
  78     // needs to take isIncremental into account because case mappings are context-sensitive
  79     //   also detect when lowercasing function did not finish because of context
  80
  81     if (offsets.start >= offsets.limit) {
  82         return;
  83     }
  84
  85     // case type: >0 cased (UCASE_LOWER etc.)  ==0 uncased  <0 case-ignorable
  86     int32_t type;
  87
  88     // Our mode; we are either converting letter toTitle or
  89     // toLower.
  90     UBool doTitle = TRUE;
  91
  92     // Determine if there is a preceding context of cased case-ignorable*,
  93     // in which case we want to start in toLower mode.  If the
  94     // prior context is anything else (including empty) then start
  95     // in toTitle mode.
  96     UChar32 c;
  97     int32_t start;
  98     for (start = offsets.start - 1; start >= offsets.contextStart; start -= U16_LENGTH(c)) {
  99         c = text.char32At(start);
 100         type=ucase_getTypeOrIgnorable(c);
 101         if(type>0) { // cased
 102             doTitle=FALSE;
 103             break;
 104         } else if(type==0) { // uncased but not ignorable
 105             break;
 106         }
 107         // else (type<0) case-ignorable: continue
 108     }
 109
 110     // Convert things after a cased character toLower; things
 111     // after an uncased, non-case-ignorable character toTitle.  Case-ignorable
 112     // characters are copied directly and do not change the mode.
 113     UCaseContext csc;
 114     uprv_memset(&csc, 0, sizeof(csc));
 115     csc.p = &text;
 116     csc.start = offsets.contextStart;
 117     csc.limit = offsets.contextLimit;
 118
 119     UnicodeString tmp;
 120     const UChar *s;
 121     int32_t textPos, delta, result;
 122
 123     for(textPos=offsets.start; textPos<offsets.limit;) {
 124         csc.cpStart=textPos;
 125         c=text.char32At(textPos);
 126         csc.cpLimit=textPos+=U16_LENGTH(c);
 127
 128         type=ucase_getTypeOrIgnorable(c);
 129         if(type>=0) { // not case-ignorable
 130             if(doTitle) {
 131                 result=ucase_toFullTitle(c, utrans_rep_caseContextIterator, &csc, &s, UCASE_LOC_ROOT);
 132             } else {
 133                 result=ucase_toFullLower(c, utrans_rep_caseContextIterator, &csc, &s, UCASE_LOC_ROOT);
 134             }
 135             doTitle = (UBool)(type==0); // doTitle=isUncased
 136
 137             if(csc.b1 && isIncremental) {
 138                 // fMap() tried to look beyond the context limit
 139                 // wait for more input
 140                 offsets.start=csc.cpStart;
 141                 return;
 142             }
 143
 144             if(result>=0) {
 145                 // replace the current code point with its full case mapping result
 146                 // see UCASE_MAX_STRING_LENGTH
 147                 if(result<=UCASE_MAX_STRING_LENGTH) {
 148                     // string s[result]
 149                     tmp.setTo(FALSE, s, result);
 150                     delta=result-U16_LENGTH(c);
 151                 } else {
 152                     // single code point
 153                     tmp.setTo(result);
 154                     delta=tmp.length()-U16_LENGTH(c);
 155                 }
 156                 text.handleReplaceBetween(csc.cpStart, textPos, tmp);
 157                 if(delta!=0) {
 158                     textPos+=delta;
 159                     csc.limit=offsets.contextLimit+=delta;
 160                     offsets.limit+=delta;
 161                 }
 162             }
 163         }
 164     }
 165     offsets.start=textPos;
 166 }
 167
 168 U_NAMESPACE_END
 169
 170 #endif /* #if !UCONFIG_NO_TRANSLITERATION */