gecko-dev/modules/libnls/headers/brkiter.h
1998-05-27 02:02:27 +00:00

284 lines
10 KiB
C++

/*
*****************************************************************************************
* *
* COPYRIGHT: *
* (C) Copyright Taligent, Inc., 1997 *
* (C) Copyright International Business Machines Corporation, 1997 *
* Licensed Material - Program-Property of IBM - All Rights Reserved. *
* US Government Users Restricted Rights - Use, duplication, or disclosure *
* restricted by GSA ADP Schedule Contract with IBM Corp. *
* *
*****************************************************************************************
*
* 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
*****************************************************************************************
*/
#ifndef _BRKITER
#define _BRKITER
#include "unistring.h"
#include "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>
* Print each element in order:
* <pre>
* . void printEachForward(const BreakIterator& boundary) {
* . UnicodeString textChunk;
* . TextOffset start = boundary.first();
* . for (TextOffset end = boundary.next();
* . end != BreakIterator::DONE;
* . start = end, end = boundary.next())
* . {
* . cout &lt;&lt; boundary.getText()->extract(start, end, textChunk);
* . }
* . }
* </pre>
* Print each element in reverse order:
* <pre>
* . void printEachbackward(const BreakIterator& boundary) {
* . UnicodeString textChunk;
* . TextOffset end = boundary.last();
* . for (TextOffset start = boundary.previous();
* . start != BreakIterator::DONE;
* . end = start, start = boundary.previous())
* . {
* . cout &lt;&lt; boundary.getText()->extract(start, end, textChunk);
* . }
* . }
* </pre>
*/
class T_FINDWORD_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.
*/
virtual t_bool operator==(const BreakIterator&) const = 0;
t_bool operator!=(const BreakIterator& rhs) const { return !operator==(rhs); }
/**
* Return a polymorphic copy of this object. This is an abstract
* method which subclasses implement.
*/
virtual BreakIterator* clone() const = 0;
/**
* Return a polymorphic class ID for this object. Different subclasses
* will return distinct unequal values.
*/
virtual ClassID getDynamicClassID() const = 0;
/**
* Get the text for which this object is finding the boundaries.
*/
virtual const UnicodeString* getText() const = 0;
/**
* Set the text for which this object should find the boundaries.
*/
virtual void setText(const UnicodeString*) = 0;
/**
* DONE is returned by previous() and next() after all valid
* boundaries have been returned.
*/
static const TextOffset DONE;
/**
* Return the index of the first character in the text being scanned.
*/
virtual TextOffset first() = 0;
/**
* Return the index immediately BEYOND the last character in the text being scanned.
*/
virtual TextOffset last() = 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.
*/
virtual TextOffset previous() = 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.
*/
virtual TextOffset next() = 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.
*/
virtual TextOffset current() 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.
*/
virtual TextOffset following(TextOffset 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.
*/
virtual TextOffset next(t_int32 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. If a specific WordBreak is not
* avaliable for the specified locale, a default WordBreak is returned.
* @return A BreakIterator for word-breaks
*/
static BreakIterator* createWordInstance(const Locale& where = Locale::getDefault());
/**
* 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. If a specific LineBreak is not
* avaliable for the specified locale, a default LineBreak is returned.
* @return A BreakIterator for line-breaks
*/
static BreakIterator* createLineInstance(const Locale& where = Locale::getDefault());
/**
* 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. If a specific character break is not
* avaliable for the specified locale, a default character break is returned.
* @return A BreakIterator for character-breaks
*/
static BreakIterator* createCharacterInstance(const Locale& where = Locale::getDefault());
/**
* Create BreakIterator for sentence-breaks using specified locale
* Returns an instance of a BreakIterator implementing sentence breaks.
* @param where the locale. If a specific SentenceBreak is not
* avaliable for the specified locale, a default SentenceBreak is returned.
* @return A BreakIterator for sentence-breaks
*/
static BreakIterator* createSentenceInstance(const Locale& where = Locale::getDefault());
/**
* 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
*/
static const Locale* getAvailableLocales(t_int32& 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
*/
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
*/
static UnicodeString& getDisplayName(const Locale& objectLocale,
UnicodeString& name);
// begin deprecated api.
virtual TextOffset nextAfter(TextOffset offset) = 0;
virtual TextOffset nthFromCurrent(t_int32 n) = 0;
static BreakIterator* createWordBreak(const Locale& where = Locale::getDefault()) { return createWordInstance(); }
static BreakIterator* createLineBreak(const Locale& where = Locale::getDefault()) { return createLineInstance(); }
static BreakIterator* createCharacterBreak(const Locale& where = Locale::getDefault()) { return createCharacterInstance(); }
static BreakIterator* createSentenceBreak(const Locale& where = Locale::getDefault()) { return createSentenceInstance(); }
// end deprecated api.
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& other) { return *this; }
BreakIterator (const BreakIterator& other) {}
};
#endif // _BRKITER
//eof