scuffed-code/icu4c/source/i18n/unicode/brkiter.h

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/*
*****************************************************************************************
* Copyright (C) 1997-2000, International Business Machines
* Corporation and others. All Rights Reserved.
*****************************************************************************************
*
* File BRKITER.H
*
* Modification History:
*
* Date Name Description
* 02/18/97 aliu Added typedef for TextCount. Made DONE const.
* 05/07/97 aliu Fixed DLL declaration.
* 07/09/97 jfitz Renamed BreakIterator and interface synced with JDK
* 08/11/98 helena Sync-up JDK1.2.
* 01/13/2000 helena Added UErrorCode parameter to createXXXInstance methods.
*****************************************************************************************
*/
#ifndef BRKITER_H
#define BRKITER_H
#include "unicode/unistr.h"
#include "unicode/chariter.h"
#include "unicode/locid.h"
//class Locale;
/**
* The BreakIterator class implements methods for finding the location
* of boundaries in text. BreakIterator is an abstract base class.
* Instances of BreakIterator maintain a current position and scan over
* text returning the index of characters where boundaries occur.
* <P>
* Line boundary analysis determines where a text string can be broken
* when line-wrapping. The mechanism correctly handles punctuation and
* hyphenated words.
* <P>
* Sentence boundary analysis allows selection with correct
* interpretation of periods within numbers and abbreviations, and
* trailing punctuation marks such as quotation marks and parentheses.
* <P>
* Word boundary analysis is used by search and replace functions, as
* well as within text editing applications that allow the user to
* select words with a double click. Word selection provides correct
* interpretation of punctuation marks within and following
* words. Characters that are not part of a word, such as symbols or
* punctuation marks, have word-breaks on both sides.
* <P>
* Character boundary analysis allows users to interact with
* characters as they expect to, for example, when moving the cursor
* through a text string. Character boundary analysis provides correct
* navigation of through character strings, regardless of how the
* character is stored. For example, an accented character might be
* stored as a base character and a diacritical mark. What users
* consider to be a character can differ between languages.
* <P>
* This is the interface for all text boundaries.
* <P>
* Examples:
* <P>
* Helper function to output text
* <pre>
* . void printTextRange( BreakIterator& iterator, UTextOffset start, UTextOffset end )
* . {
* . UnicodeString textBuffer, temp;
* . CharacterIterator *strIter = iterator.createText();
* . strIter->getText(temp);
* . cout &lt;&lt; " " &lt;&lt; start &lt;&lt; " " &lt;&lt; end &lt;&lt; " |"
* . &lt;&lt; temp.extractBetween(start, end, textBuffer)
* . &lt;&lt; "|" &lt;&lt; endl;
* . delete strIter;
* . }
* </pre>
* Print each element in order:
* <pre>
* . void printEachForward( BreakIterator& boundary)
* . {
* . UTextOffset start = boundary.first();
* . for (UTextOffset end = boundary.next();
* . end != BreakIterator::DONE;
* . start = end, end = boundary.next())
* . {
* . printTextRange( boundary, start, end );
* . }
* . }
* </pre>
* Print each element in reverse order:
* <pre>
* . void printEachBackward( BreakIterator& boundary)
* . {
* . UTextOffset end = boundary.last();
* . for (UTextOffset start = boundary.previous();
* . start != BreakIterator::DONE;
* . end = start, start = boundary.previous())
* . {
* . printTextRange( boundary, start, end );
* . }
* . }
* </pre>
* Print first element
* <pre>
* . void printFirst(BreakIterator& boundary)
* . {
* . UTextOffset start = boundary.first();
* . UTextOffset end = boundary.next();
* . printTextRange( boundary, start, end );
* . }
* </pre>
* Print last element
* <pre>
* . void printLast(BreakIterator& boundary)
* . {
* . UTextOffset end = boundary.last();
* . UTextOffset start = boundary.previous();
* . printTextRange( boundary, start, end );
* . }
* </pre>
* Print the element at a specified position
* <pre>
* . void printAt(BreakIterator &boundary, UTextOffset pos )
* . {
* . UTextOffset end = boundary.following(pos);
* . UTextOffset start = boundary.previous();
* . printTextRange( boundary, start, end );
* . }
* </pre>
* Creating and using text boundaries
* <pre>
* . void BreakIterator_Example( void )
* . {
* . BreakIterator* boundary;
* . UnicodeString stringToExamine("Aaa bbb ccc. Ddd eee fff.");
* . cout &lt;&lt; "Examining: " &lt;&lt; stringToExamine &lt;&lt; endl;
* .
* . //print each sentence in forward and reverse order
* . boundary = BreakIterator::createSentenceInstance( Locale::US );
* . boundary->setText(stringToExamine);
* . cout &lt;&lt; "----- forward: -----------" &lt;&lt; endl;
* . printEachForward(*boundary);
* . cout &lt;&lt; "----- backward: ----------" &lt;&lt; endl;
* . printEachBackward(*boundary);
* . delete boundary;
* .
* . //print each word in order
* . boundary = BreakIterator::createWordInstance();
* . boundary->setText(stringToExamine);
* . cout &lt;&lt; "----- forward: -----------" &lt;&lt; endl;
* . printEachForward(*boundary);
* . //print first element
* . cout &lt;&lt; "----- first: -------------" &lt;&lt; endl;
* . printFirst(*boundary);
* . //print last element
* . cout &lt;&lt; "----- last: --------------" &lt;&lt; endl;
* . printLast(*boundary);
* . //print word at charpos 10
* . cout &lt;&lt; "----- at pos 10: ---------" &lt;&lt; endl;
* . printAt(*boundary, 10 );
* .
* . delete boundary;
* . }
* </pre>
*/
class U_I18N_API BreakIterator {
public:
virtual ~BreakIterator();
/**
* Return true if another object is semantically equal to this
* one. The other object should be an instance of the same subclass of
* BreakIterator. Objects of different subclasses are considered
* unequal.
* <P>
* Return true if this BreakIterator is at the same position in the
* same text, and is the same class and type (word, line, etc.) of
* BreakIterator, as the argument. Text is considered the same if
* it contains the same characters, it need not be the same
* object, and styles are not considered.
* @stable
*/
virtual UBool operator==(const BreakIterator&) const = 0;
/**
* Returns the complement of the result of operator==
* @stable
*/
UBool operator!=(const BreakIterator& rhs) const { return !operator==(rhs); }
/**
* Return a polymorphic copy of this object. This is an abstract
* method which subclasses implement.
* @stable
*/
virtual BreakIterator* clone(void) const = 0;
/**
* Return a polymorphic class ID for this object. Different subclasses
* will return distinct unequal values.
* @stable
*/
virtual UClassID getDynamicClassID(void) const = 0;
/**
* Return a CharacterIterator over the text being analyzed.
* @draft
*/
virtual const CharacterIterator& getText(void) const = 0;
/**
* Get the text for which this object is finding the boundaries.
* @deprecated This will be removed after 2000-Dec-31. Use getText() instead.
*/
virtual CharacterIterator* createText(void) const = 0;
/**
* Change the text over which this operates. The text boundary is
* reset to the start.
* @deprecated Use setText(const UnicodeString&) instead.
*/
virtual void setText(const UnicodeString* it) = 0;
/**
* Change the text over which this operates. The text boundary is
* reset to the start.
* @draft
*/
virtual void setText(const UnicodeString &text) = 0;
/**
* Change the text over which this operates. The text boundary is
* reset to the start.
* @stable
*/
virtual void adoptText(CharacterIterator* it) = 0;
/**
* DONE is returned by previous() and next() after all valid
* boundaries have been returned.
* @stable
*/
static const UTextOffset DONE;
/**
* Return the index of the first character in the text being scanned.
* @stable
*/
virtual UTextOffset first(void) = 0;
/**
* Return the index immediately BEYOND the last character in the text being scanned.
* @stable
*/
virtual UTextOffset last(void) = 0;
/**
* Return the boundary preceding the current boundary.
* @return The character index of the previous text boundary or DONE if all
* boundaries have been returned.
* @stable
*/
virtual UTextOffset previous(void) = 0;
/**
* Return the boundary following the current boundary.
* @return The character index of the next text boundary or DONE if all
* boundaries have been returned.
* @stable
*/
virtual UTextOffset next(void) = 0;
/**
* Return character index of the text boundary that was most recently
* returned by next(), previous(), first(), or last()
* @return The boundary most recently returned.
* @stable
*/
virtual UTextOffset current(void) const = 0;
/**
* Return the first boundary following the specified offset.
* The value returned is always greater than the offset or
* the value BreakIterator.DONE
* @param offset the offset to begin scanning.
* @return The first boundary after the specified offset.
* @stable
*/
virtual UTextOffset following(UTextOffset offset) = 0;
/**
* Return the first boundary preceding the specified offset.
* The value returned is always smaller than the offset or
* the value BreakIterator.DONE
* @param offset the offset to begin scanning.
* @return The first boundary before the specified offset.
* @stable
*/
virtual UTextOffset preceding(UTextOffset offset) = 0;
/**
* Return true if the specfied position is a boundary position.
* @param offset the offset to check.
* @return True if "offset" is a boundary position.
* @stable
*/
virtual UBool isBoundary(UTextOffset offset) = 0;
/**
* Return the nth boundary from the current boundary
* @param n which boundary to return. A value of 0
* does nothing. Negative values move to previous boundaries
* and positive values move to later boundaries.
* @return The index of the nth boundary from the current position, or
* DONE if there are fewer than |n| boundaries in the specfied direction.
* @stable
*/
virtual UTextOffset next(int32_t n) = 0;
/**
* Create BreakIterator for word-breaks using the given locale.
* Returns an instance of a BreakIterator implementing word breaks.
* WordBreak is useful for word selection (ex. double click)
* @param where the locale.
* @param status the error code
* @return A BreakIterator for word-breaks. The UErrorCode& status
* parameter is used to return status information to the user.
* To check whether the construction succeeded or not, you should check
* the value of U_SUCCESS(err). If you wish more detailed information, you
* can check for informational error results which still indicate success.
* U_USING_FALLBACK_ERROR indicates that a fall back locale was used. For
* example, 'de_CH' was requested, but nothing was found there, so 'de' was
* used. U_USING_DEFAULT_ERROR indicates that the default locale data was
* used; neither the requested locale nor any of its fall back locales
* could be found.
* The caller owns the returned object and is responsible for deleting it.
* @draft
*/
static BreakIterator* createWordInstance(const Locale& where,
UErrorCode& status);
/**
* Create BreakIterator for line-breaks using specified locale.
* Returns an instance of a BreakIterator implementing line breaks. Line
* breaks are logically possible line breaks, actual line breaks are
* usually determined based on display width.
* LineBreak is useful for word wrapping text.
* @param where the locale. .
* @return A BreakIterator for line-breaks. The UErrorCode& status
* parameter is used to return status information to the user.
* To check whether the construction succeeded or not, you should check
* the value of U_SUCCESS(err). If you wish more detailed information, you
* can check for informational error results which still indicate success.
* U_USING_FALLBACK_ERROR indicates that a fall back locale was used. For
* example, 'de_CH' was requested, but nothing was found there, so 'de' was
* used. U_USING_DEFAULT_ERROR indicates that the default locale data was
* used; neither the requested locale nor any of its fall back locales
* could be found.
* The caller owns the returned object and is responsible for deleting it.
* @draft
*/
static BreakIterator* createLineInstance(const Locale& where,
UErrorCode& status);
/**
* Create BreakIterator for character-breaks using specified locale
* Returns an instance of a BreakIterator implementing character breaks.
* Character breaks are boundaries of combining character sequences.
* @param where the locale.
* @return A BreakIterator for character-breaks. The UErrorCode& status
* parameter is used to return status information to the user.
* To check whether the construction succeeded or not, you should check
* the value of U_SUCCESS(err). If you wish more detailed information, you
* can check for informational error results which still indicate success.
* U_USING_FALLBACK_ERROR indicates that a fall back locale was used. For
* example, 'de_CH' was requested, but nothing was found there, so 'de' was
* used. U_USING_DEFAULT_ERROR indicates that the default locale data was
* used; neither the requested locale nor any of its fall back locales
* could be found.
* The caller owns the returned object and is responsible for deleting it.
* @draft
*/
static BreakIterator* createCharacterInstance(const Locale& where,
UErrorCode& status);
/**
* Create BreakIterator for sentence-breaks using specified locale
* Returns an instance of a BreakIterator implementing sentence breaks.
* @param where the locale.
* @return A BreakIterator for sentence-breaks. The UErrorCode& status
* parameter is used to return status information to the user.
* To check whether the construction succeeded or not, you should check
* the value of U_SUCCESS(err). If you wish more detailed information, you
* can check for informational error results which still indicate success.
* U_USING_FALLBACK_ERROR indicates that a fall back locale was used. For
* example, 'de_CH' was requested, but nothing was found there, so 'de' was
* used. U_USING_DEFAULT_ERROR indicates that the default locale data was
* used; neither the requested locale nor any of its fall back locales
* could be found.
* The caller owns the returned object and is responsible for deleting it.
* @draft
*/
static BreakIterator* createSentenceInstance(const Locale& where,
UErrorCode& status);
/**
* Get the set of Locales for which TextBoundaries are installed
* @param count the output parameter of number of elements in the locale list
* @return available locales
* @stable
*/
static const Locale* getAvailableLocales(int32_t& count);
/**
* Get name of the object for the desired Locale, in the desired langauge.
* @param objectLocale must be from getAvailableLocales.
* @param displayLocale specifies the desired locale for output.
* @param name the fill-in parameter of the return value
* Uses best match.
* @return user-displayable name
* @stable
*/
static UnicodeString& getDisplayName(const Locale& objectLocale,
const Locale& displayLocale,
UnicodeString& name);
/**
* Get name of the object for the desired Locale, in the langauge of the
* default locale.
* @param objectLocale must be from getMatchingLocales
* @param name the fill-in parameter of the return value
* @return user-displayable name
* @stable
*/
static UnicodeString& getDisplayName(const Locale& objectLocale,
UnicodeString& name);
protected:
BreakIterator();
private:
/**
* The copy constructor and assignment operator have no real implementation.
* They are provided to make the compiler happy. Do not call.
*/
BreakIterator& operator=(const BreakIterator&) { return *this; }
BreakIterator (const BreakIterator&) {}
};
#endif // _BRKITER
//eof