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1 /*
2 ********************************************************************************
3 *   Copyright (C) 1997-2010, International Business Machines
4 *   Corporation and others.  All Rights Reserved.
5 ********************************************************************************
6 *
7 * File brkiter.h
8 *
9 * Modification History:
10 *
11 *   Date        Name        Description
12 *   02/18/97    aliu        Added typedef for TextCount.  Made DONE const.
13 *   05/07/97    aliu        Fixed DLL declaration.
14 *   07/09/97    jfitz       Renamed BreakIterator and interface synced with JDK
15 *   08/11/98    helena      Sync-up JDK1.2.
16 *   01/13/2000  helena      Added UErrorCode parameter to createXXXInstance methods.
17 ********************************************************************************
18 */
19 
20 #ifndef BRKITER_H
21 #define BRKITER_H
22 
23 #include "unicode/utypes.h"
24 
25 /**
26  * \file
27  * \brief C++ API: Break Iterator.
28  */
29 
30 #if UCONFIG_NO_BREAK_ITERATION
31 
32 U_NAMESPACE_BEGIN
33 
34 /*
35  * Allow the declaration of APIs with pointers to BreakIterator
36  * even when break iteration is removed from the build.
37  */
38 class BreakIterator;
39 
40 U_NAMESPACE_END
41 
42 #else
43 
44 #include "unicode/uobject.h"
45 #include "unicode/unistr.h"
46 #include "unicode/chariter.h"
47 #include "unicode/locid.h"
48 #include "unicode/ubrk.h"
49 #include "unicode/strenum.h"
50 #include "unicode/utext.h"
51 #include "unicode/umisc.h"
52 
53 U_NAMESPACE_BEGIN
54 
55 /**
56  * The BreakIterator class implements methods for finding the location
57  * of boundaries in text. BreakIterator is an abstract base class.
58  * Instances of BreakIterator maintain a current position and scan over
59  * text returning the index of characters where boundaries occur.
60  * <p>
61  * Line boundary analysis determines where a text string can be broken
62  * when line-wrapping. The mechanism correctly handles punctuation and
63  * hyphenated words.
64  * <p>
65  * Sentence boundary analysis allows selection with correct
66  * interpretation of periods within numbers and abbreviations, and
67  * trailing punctuation marks such as quotation marks and parentheses.
68  * <p>
69  * Word boundary analysis is used by search and replace functions, as
70  * well as within text editing applications that allow the user to
71  * select words with a double click. Word selection provides correct
72  * interpretation of punctuation marks within and following
73  * words. Characters that are not part of a word, such as symbols or
74  * punctuation marks, have word-breaks on both sides.
75  * <p>
76  * Character boundary analysis allows users to interact with
77  * characters as they expect to, for example, when moving the cursor
78  * through a text string. Character boundary analysis provides correct
79  * navigation of through character strings, regardless of how the
80  * character is stored.  For example, an accented character might be
81  * stored as a base character and a diacritical mark. What users
82  * consider to be a character can differ between languages.
83  * <p>
84  * The text boundary positions are found according to the rules
85  * described in Unicode Standard Annex #29, Text Boundaries, and
86  * Unicode Standard Annex #14, Line Breaking Properties.  These
87  * are available at http://www.unicode.org/reports/tr14/ and
88  * http://www.unicode.org/reports/tr29/.
89  * <p>
90  * In addition to the C++ API defined in this header file, a
91  * plain C API with equivalent functionality is defined in the
92  * file ubrk.h
93  * <p>
94  * Code snippets illustrating the use of the Break Iterator APIs
95  * are available in the ICU User Guide,
96  * http://icu-project.org/userguide/boundaryAnalysis.html
97  * and in the sample program icu/source/samples/break/break.cpp
98  *
99  */
100 class U_COMMON_API BreakIterator : public UObject {
101 public:
102     /**
103      *  destructor
104      *  @stable ICU 2.0
105      */
106     virtual ~BreakIterator();
107 
108     /**
109      * Return true if another object is semantically equal to this
110      * one. The other object should be an instance of the same subclass of
111      * BreakIterator. Objects of different subclasses are considered
112      * unequal.
113      * <P>
114      * Return true if this BreakIterator is at the same position in the
115      * same text, and is the same class and type (word, line, etc.) of
116      * BreakIterator, as the argument.  Text is considered the same if
117      * it contains the same characters, it need not be the same
118      * object, and styles are not considered.
119      * @stable ICU 2.0
120      */
121     virtual UBool operator==(const BreakIterator&) const = 0;
122 
123     /**
124      * Returns the complement of the result of operator==
125      * @param rhs The BreakIterator to be compared for inequality
126      * @return the complement of the result of operator==
127      * @stable ICU 2.0
128      */
129     UBool operator!=(const BreakIterator& rhs) const { return !operator==(rhs); }
130 
131     /**
132      * Return a polymorphic copy of this object.  This is an abstract
133      * method which subclasses implement.
134      * @stable ICU 2.0
135      */
136     virtual BreakIterator* clone(void) const = 0;
137 
138     /**
139      * Return a polymorphic class ID for this object. Different subclasses
140      * will return distinct unequal values.
141      * @stable ICU 2.0
142      */
143     virtual UClassID getDynamicClassID(void) const = 0;
144 
145     /**
146      * Return a CharacterIterator over the text being analyzed.
147      * @stable ICU 2.0
148      */
149     virtual CharacterIterator& getText(void) const = 0;
150 
151 
152     /**
153       *  Get a UText for the text being analyzed.
154       *  The returned UText is a shallow clone of the UText used internally
155       *  by the break iterator implementation.  It can safely be used to
156       *  access the text without impacting any break iterator operations,
157       *  but the underlying text itself must not be altered.
158       *
159       * @param fillIn A UText to be filled in.  If NULL, a new UText will be
160       *           allocated to hold the result.
161       * @param status receives any error codes.
162       * @return   The current UText for this break iterator.  If an input
163       *           UText was provided, it will always be returned.
164       * @stable ICU 3.4
165       */
166      virtual UText *getUText(UText *fillIn, UErrorCode &status) const = 0;
167 
168     /**
169      * Change the text over which this operates. The text boundary is
170      * reset to the start.
171      * @param text The UnicodeString used to change the text.
172      * @stable ICU 2.0
173      */
174     virtual void  setText(const UnicodeString &text) = 0;
175 
176     /**
177      * Reset the break iterator to operate over the text represented by
178      * the UText.  The iterator position is reset to the start.
179      *
180      * This function makes a shallow clone of the supplied UText.  This means
181      * that the caller is free to immediately close or otherwise reuse the
182      * Utext that was passed as a parameter, but that the underlying text itself
183      * must not be altered while being referenced by the break iterator.
184      *
185      * @param text The UText used to change the text.
186      * @param status receives any error codes.
187      * @stable ICU 3.4
188      */
189     virtual void  setText(UText *text, UErrorCode &status) = 0;
190 
191     /**
192      * Change the text over which this operates. The text boundary is
193      * reset to the start.
194      * Note that setText(UText *) provides similar functionality to this function,
195      * and is more efficient.
196      * @param it The CharacterIterator used to change the text.
197      * @stable ICU 2.0
198      */
199     virtual void  adoptText(CharacterIterator* it) = 0;
200 
201     enum {
202         /**
203          * DONE is returned by previous() and next() after all valid
204          * boundaries have been returned.
205          * @stable ICU 2.0
206          */
207         DONE = (int32_t)-1
208     };
209 
210     /**
211      * Return the index of the first character in the text being scanned.
212      * @stable ICU 2.0
213      */
214     virtual int32_t first(void) = 0;
215 
216     /**
217      * Return the index immediately BEYOND the last character in the text being scanned.
218      * @stable ICU 2.0
219      */
220     virtual int32_t last(void) = 0;
221 
222     /**
223      * Return the boundary preceding the current boundary.
224      * @return The character index of the previous text boundary or DONE if all
225      * boundaries have been returned.
226      * @stable ICU 2.0
227      */
228     virtual int32_t previous(void) = 0;
229 
230     /**
231      * Return the boundary following the current boundary.
232      * @return The character index of the next text boundary or DONE if all
233      * boundaries have been returned.
234      * @stable ICU 2.0
235      */
236     virtual int32_t next(void) = 0;
237 
238     /**
239      * Return character index of the current interator position within the text.
240      * @return The boundary most recently returned.
241      * @stable ICU 2.0
242      */
243     virtual int32_t current(void) const = 0;
244 
245     /**
246      * Return the first boundary following the specified offset.
247      * The value returned is always greater than the offset or
248      * the value BreakIterator.DONE
249      * @param offset the offset to begin scanning.
250      * @return The first boundary after the specified offset.
251      * @stable ICU 2.0
252      */
253     virtual int32_t following(int32_t offset) = 0;
254 
255     /**
256      * Return the first boundary preceding the specified offset.
257      * The value returned is always smaller than the offset or
258      * the value BreakIterator.DONE
259      * @param offset the offset to begin scanning.
260      * @return The first boundary before the specified offset.
261      * @stable ICU 2.0
262      */
263     virtual int32_t preceding(int32_t offset) = 0;
264 
265     /**
266      * Return true if the specfied position is a boundary position.
267      * As a side effect, the current position of the iterator is set
268      * to the first boundary position at or following the specified offset.
269      * @param offset the offset to check.
270      * @return True if "offset" is a boundary position.
271      * @stable ICU 2.0
272      */
273     virtual UBool isBoundary(int32_t offset) = 0;
274 
275     /**
276      * Return the nth boundary from the current boundary
277      * @param n which boundary to return.  A value of 0
278      * does nothing.  Negative values move to previous boundaries
279      * and positive values move to later boundaries.
280      * @return The index of the nth boundary from the current position, or
281      * DONE if there are fewer than |n| boundaries in the specfied direction.
282      * @stable ICU 2.0
283      */
284     virtual int32_t next(int32_t n) = 0;
285 
286     /**
287      * For RuleBasedBreakIterators, return the status tag from the
288      * break rule that determined the most recently
289      * returned break position.
290      * <p>
291      * For break iterator types that do not support a rule status,
292      * a default value of 0 is returned.
293      * <p>
294      * @return the status from the break rule that determined the most recently
295      *         returned break position.
296      * @see RuleBaseBreakIterator::getRuleStatus()
297      * @see UWordBreak
298      */
299     virtual int32_t getRuleStatus() const;
300 
301     /**
302      * Create BreakIterator for word-breaks using the given locale.
303      * Returns an instance of a BreakIterator implementing word breaks.
304      * WordBreak is useful for word selection (ex. double click)
305      * @param where the locale.
306      * @param status the error code
307      * @return A BreakIterator for word-breaks.  The UErrorCode& status
308      * parameter is used to return status information to the user.
309      * To check whether the construction succeeded or not, you should check
310      * the value of U_SUCCESS(err).  If you wish more detailed information, you
311      * can check for informational error results which still indicate success.
312      * U_USING_FALLBACK_WARNING indicates that a fall back locale was used.  For
313      * example, 'de_CH' was requested, but nothing was found there, so 'de' was
314      * used.  U_USING_DEFAULT_WARNING indicates that the default locale data was
315      * used; neither the requested locale nor any of its fall back locales
316      * could be found.
317      * The caller owns the returned object and is responsible for deleting it.
318      * @stable ICU 2.0
319      */
320     static BreakIterator* U_EXPORT2
321     createWordInstance(const Locale& where, UErrorCode& status);
322 
323     /**
324      * Create BreakIterator for line-breaks using specified locale.
325      * Returns an instance of a BreakIterator implementing line breaks. Line
326      * breaks are logically possible line breaks, actual line breaks are
327      * usually determined based on display width.
328      * LineBreak is useful for word wrapping text.
329      * @param where the locale.
330      * @param status The error code.
331      * @return A BreakIterator for line-breaks.  The UErrorCode& status
332      * parameter is used to return status information to the user.
333      * To check whether the construction succeeded or not, you should check
334      * the value of U_SUCCESS(err).  If you wish more detailed information, you
335      * can check for informational error results which still indicate success.
336      * U_USING_FALLBACK_WARNING indicates that a fall back locale was used.  For
337      * example, 'de_CH' was requested, but nothing was found there, so 'de' was
338      * used.  U_USING_DEFAULT_WARNING indicates that the default locale data was
339      * used; neither the requested locale nor any of its fall back locales
340      * could be found.
341      * The caller owns the returned object and is responsible for deleting it.
342      * @stable ICU 2.0
343      */
344     static BreakIterator* U_EXPORT2
345     createLineInstance(const Locale& where, UErrorCode& status);
346 
347     /**
348      * Create BreakIterator for character-breaks using specified locale
349      * Returns an instance of a BreakIterator implementing character breaks.
350      * Character breaks are boundaries of combining character sequences.
351      * @param where the locale.
352      * @param status The error code.
353      * @return A BreakIterator for character-breaks.  The UErrorCode& status
354      * parameter is used to return status information to the user.
355      * To check whether the construction succeeded or not, you should check
356      * the value of U_SUCCESS(err).  If you wish more detailed information, you
357      * can check for informational error results which still indicate success.
358      * U_USING_FALLBACK_WARNING indicates that a fall back locale was used.  For
359      * example, 'de_CH' was requested, but nothing was found there, so 'de' was
360      * used.  U_USING_DEFAULT_WARNING indicates that the default locale data was
361      * used; neither the requested locale nor any of its fall back locales
362      * could be found.
363      * The caller owns the returned object and is responsible for deleting it.
364      * @stable ICU 2.0
365      */
366     static BreakIterator* U_EXPORT2
367     createCharacterInstance(const Locale& where, UErrorCode& status);
368 
369     /**
370      * Create BreakIterator for sentence-breaks using specified locale
371      * Returns an instance of a BreakIterator implementing sentence breaks.
372      * @param where the locale.
373      * @param status The error code.
374      * @return A BreakIterator for sentence-breaks.  The UErrorCode& status
375      * parameter is used to return status information to the user.
376      * To check whether the construction succeeded or not, you should check
377      * the value of U_SUCCESS(err).  If you wish more detailed information, you
378      * can check for informational error results which still indicate success.
379      * U_USING_FALLBACK_WARNING indicates that a fall back locale was used.  For
380      * example, 'de_CH' was requested, but nothing was found there, so 'de' was
381      * used.  U_USING_DEFAULT_WARNING indicates that the default locale data was
382      * used; neither the requested locale nor any of its fall back locales
383      * could be found.
384      * The caller owns the returned object and is responsible for deleting it.
385      * @stable ICU 2.0
386      */
387     static BreakIterator* U_EXPORT2
388     createSentenceInstance(const Locale& where, UErrorCode& status);
389 
390     /**
391      * Create BreakIterator for title-casing breaks using the specified locale
392      * Returns an instance of a BreakIterator implementing title breaks.
393      * The iterator returned locates title boundaries as described for
394      * Unicode 3.2 only. For Unicode 4.0 and above title boundary iteration,
395      * please use Word Boundary iterator.{@link #createWordInstance }
396      *
397      * @param where the locale.
398      * @param status The error code.
399      * @return A BreakIterator for title-breaks.  The UErrorCode& status
400      * parameter is used to return status information to the user.
401      * To check whether the construction succeeded or not, you should check
402      * the value of U_SUCCESS(err).  If you wish more detailed information, you
403      * can check for informational error results which still indicate success.
404      * U_USING_FALLBACK_WARNING indicates that a fall back locale was used.  For
405      * example, 'de_CH' was requested, but nothing was found there, so 'de' was
406      * used.  U_USING_DEFAULT_WARNING indicates that the default locale data was
407      * used; neither the requested locale nor any of its fall back locales
408      * could be found.
409      * The caller owns the returned object and is responsible for deleting it.
410      * @stable ICU 2.1
411      */
412     static BreakIterator* U_EXPORT2
413     createTitleInstance(const Locale& where, UErrorCode& status);
414 
415     /**
416      * Get the set of Locales for which TextBoundaries are installed.
417      * <p><b>Note:</b> this will not return locales added through the register
418      * call. To see the registered locales too, use the getAvailableLocales
419      * function that returns a StringEnumeration object </p>
420      * @param count the output parameter of number of elements in the locale list
421      * @return available locales
422      * @stable ICU 2.0
423      */
424     static const Locale* U_EXPORT2 getAvailableLocales(int32_t& count);
425 
426     /**
427      * Get name of the object for the desired Locale, in the desired langauge.
428      * @param objectLocale must be from getAvailableLocales.
429      * @param displayLocale specifies the desired locale for output.
430      * @param name the fill-in parameter of the return value
431      * Uses best match.
432      * @return user-displayable name
433      * @stable ICU 2.0
434      */
435     static UnicodeString& U_EXPORT2 getDisplayName(const Locale& objectLocale,
436                                          const Locale& displayLocale,
437                                          UnicodeString& name);
438 
439     /**
440      * Get name of the object for the desired Locale, in the langauge of the
441      * default locale.
442      * @param objectLocale must be from getMatchingLocales
443      * @param name the fill-in parameter of the return value
444      * @return user-displayable name
445      * @stable ICU 2.0
446      */
447     static UnicodeString& U_EXPORT2 getDisplayName(const Locale& objectLocale,
448                                          UnicodeString& name);
449 
450     /**
451      * Thread safe client-buffer-based cloning operation
452      *    Do NOT call delete on a safeclone, since 'new' is not used to create it.
453      * @param stackBuffer user allocated space for the new clone. If NULL new memory will be allocated.
454      * If buffer is not large enough, new memory will be allocated.
455      * @param BufferSize reference to size of allocated space.
456      * If BufferSize == 0, a sufficient size for use in cloning will
457      * be returned ('pre-flighting')
458      * If BufferSize is not enough for a stack-based safe clone,
459      * new memory will be allocated.
460      * @param status to indicate whether the operation went on smoothly or there were errors
461      *  An informational status value, U_SAFECLONE_ALLOCATED_ERROR, is used if any allocations were
462      *  necessary.
463      * @return pointer to the new clone
464      *
465      * @stable ICU 2.0
466      */
467     virtual BreakIterator *  createBufferClone(void *stackBuffer,
468                                                int32_t &BufferSize,
469                                                UErrorCode &status) = 0;
470 
471     /**
472      *   Determine whether the BreakIterator was created in user memory by
473      *   createBufferClone(), and thus should not be deleted.  Such objects
474      *   must be closed by an explicit call to the destructor (not delete).
475      *  @stable ICU 2.0
476      */
477     inline UBool isBufferClone(void);
478 
479 #if !UCONFIG_NO_SERVICE
480     /**
481      * Register a new break iterator of the indicated kind, to use in the given locale.
482      * The break iterator will be adopted.  Clones of the iterator will be returned
483      * if a request for a break iterator of the given kind matches or falls back to
484      * this locale.
485      * @param toAdopt the BreakIterator instance to be adopted
486      * @param locale the Locale for which this instance is to be registered
487      * @param kind the type of iterator for which this instance is to be registered
488      * @param status the in/out status code, no special meanings are assigned
489      * @return a registry key that can be used to unregister this instance
490      * @stable ICU 2.4
491      */
492     static URegistryKey U_EXPORT2 registerInstance(BreakIterator* toAdopt,
493                                         const Locale& locale,
494                                         UBreakIteratorType kind,
495                                         UErrorCode& status);
496 
497     /**
498      * Unregister a previously-registered BreakIterator using the key returned from the
499      * register call.  Key becomes invalid after a successful call and should not be used again.
500      * The BreakIterator corresponding to the key will be deleted.
501      * @param key the registry key returned by a previous call to registerInstance
502      * @param status the in/out status code, no special meanings are assigned
503      * @return TRUE if the iterator for the key was successfully unregistered
504      * @stable ICU 2.4
505      */
506     static UBool U_EXPORT2 unregister(URegistryKey key, UErrorCode& status);
507 
508     /**
509      * Return a StringEnumeration over the locales available at the time of the call,
510      * including registered locales.
511      * @return a StringEnumeration over the locales available at the time of the call
512      * @stable ICU 2.4
513      */
514     static StringEnumeration* U_EXPORT2 getAvailableLocales(void);
515 #endif
516 
517     /**
518      * Returns the locale for this break iterator. Two flavors are available: valid and
519      * actual locale.
520      * @stable ICU 2.8
521      */
522     Locale getLocale(ULocDataLocaleType type, UErrorCode& status) const;
523 
524     /** Get the locale for this break iterator object. You can choose between valid and actual locale.
525      *  @param type type of the locale we're looking for (valid or actual)
526      *  @param status error code for the operation
527      *  @return the locale
528      *  @internal
529      */
530     const char *getLocaleID(ULocDataLocaleType type, UErrorCode& status) const;
531 
532  private:
533     static BreakIterator* buildInstance(const Locale& loc, const char *type, int32_t kind, UErrorCode& status);
534     static BreakIterator* createInstance(const Locale& loc, int32_t kind, UErrorCode& status);
535     static BreakIterator* makeInstance(const Locale& loc, int32_t kind, UErrorCode& status);
536 
537     friend class ICUBreakIteratorFactory;
538     friend class ICUBreakIteratorService;
539 
540 protected:
541     /** @internal */
542     BreakIterator();
543     /** @internal */
544     UBool fBufferClone;
545     /** @internal */
546     BreakIterator (const BreakIterator &other) : UObject(other), fBufferClone(FALSE) {}
547 
548 private:
549 
550     /** @internal */
551     char actualLocale[ULOC_FULLNAME_CAPACITY];
552     char validLocale[ULOC_FULLNAME_CAPACITY];
553 
554     /**
555      * The assignment operator has no real implementation.
556      * It's provided to make the compiler happy. Do not call.
557      */
558     BreakIterator& operator=(const BreakIterator&);
559 };
560 
561 inline UBool BreakIterator::isBufferClone()
562 {
563     return fBufferClone;
564 }
565 
566 U_NAMESPACE_END
567 
568 #endif /* #if !UCONFIG_NO_BREAK_ITERATION */
569 
570 #endif // _BRKITER
571 //eof
572 
573