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284 lines
10 KiB
C++
284 lines
10 KiB
C++
/*
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*****************************************************************************************
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* *
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* COPYRIGHT: *
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* (C) Copyright Taligent, Inc., 1997 *
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* (C) Copyright International Business Machines Corporation, 1997 *
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* Licensed Material - Program-Property of IBM - All Rights Reserved. *
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* US Government Users Restricted Rights - Use, duplication, or disclosure *
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* restricted by GSA ADP Schedule Contract with IBM Corp. *
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* *
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*****************************************************************************************
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*
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* File BRKITER.H
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*
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* Modification History:
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*
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* Date Name Description
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* 02/18/97 aliu Added typedef for TextCount. Made DONE const.
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* 05/07/97 aliu Fixed DLL declaration.
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* 07/09/97 jfitz Renamed BreakIterator and interface synced with JDK
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*****************************************************************************************
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*/
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#ifndef _BRKITER
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#define _BRKITER
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#include "unistring.h"
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#include "locid.h"
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class Locale;
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/**
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* The BreakIterator class implements methods for finding the location
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* of boundaries in text. BreakIterator is an abstract base class.
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* Instances of BreakIterator maintain a current position and scan over
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* text returning the index of characters where boundaries occur.
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* <P>
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* Line boundary analysis determines where a text string can be broken
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* when line-wrapping. The mechanism correctly handles punctuation and
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* hyphenated words.
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* <P>
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* Sentence boundary analysis allows selection with correct
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* interpretation of periods within numbers and abbreviations, and
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* trailing punctuation marks such as quotation marks and parentheses.
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* <P>
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* Word boundary analysis is used by search and replace functions, as
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* well as within text editing applications that allow the user to
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* select words with a double click. Word selection provides correct
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* interpretation of punctuation marks within and following
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* words. Characters that are not part of a word, such as symbols or
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* punctuation marks, have word-breaks on both sides.
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* <P>
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* Character boundary analysis allows users to interact with
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* characters as they expect to, for example, when moving the cursor
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* through a text string. Character boundary analysis provides correct
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* navigation of through character strings, regardless of how the
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* character is stored. For example, an accented character might be
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* stored as a base character and a diacritical mark. What users
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* consider to be a character can differ between languages.
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* <P>
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* This is the interface for all text boundaries.
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* <P>
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* Examples:
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* <P>
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* Print each element in order:
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* <pre>
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* . void printEachForward(const BreakIterator& boundary) {
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* . UnicodeString textChunk;
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* . TextOffset start = boundary.first();
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* . for (TextOffset end = boundary.next();
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* . end != BreakIterator::DONE;
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* . start = end, end = boundary.next())
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* . {
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* . cout << boundary.getText()->extract(start, end, textChunk);
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* . }
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* . }
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* </pre>
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* Print each element in reverse order:
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* <pre>
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* . void printEachbackward(const BreakIterator& boundary) {
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* . UnicodeString textChunk;
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* . TextOffset end = boundary.last();
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* . for (TextOffset start = boundary.previous();
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* . start != BreakIterator::DONE;
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* . end = start, start = boundary.previous())
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* . {
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* . cout << boundary.getText()->extract(start, end, textChunk);
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* . }
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* . }
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* </pre>
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*/
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class T_FINDWORD_API BreakIterator {
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public:
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virtual ~BreakIterator();
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/**
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* Return true if another object is semantically equal to this
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* one. The other object should be an instance of the same subclass of
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* BreakIterator. Objects of different subclasses are considered
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* unequal.
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* <P>
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* Return true if this BreakIterator is at the same position in the
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* same text, and is the same class and type (word, line, etc.) of
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* BreakIterator, as the argument. Text is considered the same if
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* it contains the same characters, it need not be the same
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* object, and styles are not considered.
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*/
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virtual t_bool operator==(const BreakIterator&) const = 0;
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t_bool operator!=(const BreakIterator& rhs) const { return !operator==(rhs); }
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/**
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* Return a polymorphic copy of this object. This is an abstract
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* method which subclasses implement.
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*/
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virtual BreakIterator* clone() const = 0;
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/**
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* Return a polymorphic class ID for this object. Different subclasses
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* will return distinct unequal values.
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*/
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virtual ClassID getDynamicClassID() const = 0;
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/**
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* Get the text for which this object is finding the boundaries.
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*/
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virtual const UnicodeString* getText() const = 0;
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/**
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* Set the text for which this object should find the boundaries.
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*/
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virtual void setText(const UnicodeString*) = 0;
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/**
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* DONE is returned by previous() and next() after all valid
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* boundaries have been returned.
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*/
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static const TextOffset DONE;
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/**
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* Return the index of the first character in the text being scanned.
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*/
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virtual TextOffset first() = 0;
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/**
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* Return the index immediately BEYOND the last character in the text being scanned.
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*/
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virtual TextOffset last() = 0;
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/**
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* Return the boundary preceding the current boundary.
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* @return The character index of the previous text boundary or DONE if all
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* boundaries have been returned.
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*/
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virtual TextOffset previous() = 0;
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/**
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* Return the boundary following the current boundary.
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* @return The character index of the next text boundary or DONE if all
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* boundaries have been returned.
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*/
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virtual TextOffset next() = 0;
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/**
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* Return character index of the text boundary that was most recently
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* returned by next(), previous(), first(), or last()
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* @return The boundary most recently returned.
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*/
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virtual TextOffset current() const = 0;
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/**
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* Return the first boundary following the specified offset.
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* The value returned is always greater than the offset or
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* the value BreakIterator.DONE
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* @param offset the offset to begin scanning.
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* @return The first boundary after the specified offset.
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*/
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virtual TextOffset following(TextOffset offset) = 0;
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/**
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* Return the nth boundary from the current boundary
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* @param n which boundary to return. A value of 0
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* does nothing. Negative values move to previous boundaries
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* and positive values move to later boundaries.
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* @return The index of the nth boundary from the current position, or
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* DONE if there are fewer than |n| boundaries in the specfied direction.
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*/
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virtual TextOffset next(t_int32 n) = 0;
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/**
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* Create BreakIterator for word-breaks using the given locale.
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* Returns an instance of a BreakIterator implementing word breaks.
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* WordBreak is useful for word selection (ex. double click)
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* @param where the locale. If a specific WordBreak is not
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* avaliable for the specified locale, a default WordBreak is returned.
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* @return A BreakIterator for word-breaks
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*/
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static BreakIterator* createWordInstance(const Locale& where = Locale::getDefault());
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/**
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* Create BreakIterator for line-breaks using specified locale.
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* Returns an instance of a BreakIterator implementing line breaks. Line
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* breaks are logically possible line breaks, actual line breaks are
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* usually determined based on display width.
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* LineBreak is useful for word wrapping text.
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* @param where the locale. If a specific LineBreak is not
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* avaliable for the specified locale, a default LineBreak is returned.
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* @return A BreakIterator for line-breaks
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*/
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static BreakIterator* createLineInstance(const Locale& where = Locale::getDefault());
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/**
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* Create BreakIterator for character-breaks using specified locale
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* Returns an instance of a BreakIterator implementing character breaks.
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* Character breaks are boundaries of combining character sequences.
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* @param where the locale. If a specific character break is not
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* avaliable for the specified locale, a default character break is returned.
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* @return A BreakIterator for character-breaks
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*/
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static BreakIterator* createCharacterInstance(const Locale& where = Locale::getDefault());
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/**
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* Create BreakIterator for sentence-breaks using specified locale
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* Returns an instance of a BreakIterator implementing sentence breaks.
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* @param where the locale. If a specific SentenceBreak is not
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* avaliable for the specified locale, a default SentenceBreak is returned.
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* @return A BreakIterator for sentence-breaks
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*/
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static BreakIterator* createSentenceInstance(const Locale& where = Locale::getDefault());
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/**
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* Get the set of Locales for which TextBoundaries are installed
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* @param count the output parameter of number of elements in the locale list
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* @return available locales
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*/
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static const Locale* getAvailableLocales(t_int32& count);
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/**
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* Get name of the object for the desired Locale, in the desired langauge.
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* @param objectLocale must be from getAvailableLocales.
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* @param displayLocale specifies the desired locale for output.
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* @param name the fill-in parameter of the return value
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* Uses best match.
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* @return user-displayable name
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*/
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static UnicodeString& getDisplayName(const Locale& objectLocale,
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const Locale& displayLocale,
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UnicodeString& name);
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/**
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* Get name of the object for the desired Locale, in the langauge of the
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* default locale.
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* @param objectLocale must be from getMatchingLocales
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* @param name the fill-in parameter of the return value
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* @return user-displayable name
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*/
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static UnicodeString& getDisplayName(const Locale& objectLocale,
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UnicodeString& name);
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// begin deprecated api.
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virtual TextOffset nextAfter(TextOffset offset) = 0;
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virtual TextOffset nthFromCurrent(t_int32 n) = 0;
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static BreakIterator* createWordBreak(const Locale& where = Locale::getDefault()) { return createWordInstance(); }
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static BreakIterator* createLineBreak(const Locale& where = Locale::getDefault()) { return createLineInstance(); }
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static BreakIterator* createCharacterBreak(const Locale& where = Locale::getDefault()) { return createCharacterInstance(); }
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static BreakIterator* createSentenceBreak(const Locale& where = Locale::getDefault()) { return createSentenceInstance(); }
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// end deprecated api.
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protected:
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BreakIterator();
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private:
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/**
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* The copy constructor and assignment operator have no real implementation.
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* They are provided to make the compiler happy. Do not call.
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*/
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BreakIterator& operator=(const BreakIterator& other) { return *this; }
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BreakIterator (const BreakIterator& other) {}
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};
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#endif // _BRKITER
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//eof
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