sl@0: /*
sl@0: * Copyright (C) 1999-2005, International Business Machines Corporation and others.
sl@0: * All Rights Reserved.
sl@0: **********************************************************************
sl@0: *   Date        Name        Description
sl@0: *   11/17/99    aliu        Creation.
sl@0: **********************************************************************
sl@0: */
sl@0: #ifndef UNIFILT_H
sl@0: #define UNIFILT_H
sl@0: 
sl@0: #include "unicode/unifunct.h"
sl@0: #include "unicode/unimatch.h"
sl@0: 
sl@0: /**
sl@0:  * \file 
sl@0:  * \brief C++ API: Unicode Filter
sl@0:  */
sl@0: 
sl@0: U_NAMESPACE_BEGIN
sl@0: 
sl@0: /**
sl@0:  * U_ETHER is used to represent character values for positions outside
sl@0:  * a range.  For example, transliterator uses this to represent
sl@0:  * characters outside the range contextStart..contextLimit-1.  This
sl@0:  * allows explicit matching by rules and UnicodeSets of text outside a
sl@0:  * defined range.
sl@0:  * @draft ICU 3.0
sl@0:  */
sl@0: #define U_ETHER ((UChar)0xFFFF)
sl@0: 
sl@0: /**
sl@0:  *
sl@0:  * <code>UnicodeFilter</code> defines a protocol for selecting a
sl@0:  * subset of the full range (U+0000 to U+10FFFF) of Unicode characters.
sl@0:  * Currently, filters are used in conjunction with classes like {@link
sl@0:  * Transliterator} to only process selected characters through a
sl@0:  * transformation.
sl@0:  *
sl@0:  * <p>Note: UnicodeFilter currently stubs out two pure virtual methods
sl@0:  * of its base class, UnicodeMatcher.  These methods are toPattern()
sl@0:  * and matchesIndexValue().  This is done so that filter classes that
sl@0:  * are not actually used as matchers -- specifically, those in the
sl@0:  * UnicodeFilterLogic component, and those in tests -- can continue to
sl@0:  * work without defining these methods.  As long as a filter is not
sl@0:  * used in an RBT during real transliteration, these methods will not
sl@0:  * be called.  However, this breaks the UnicodeMatcher base class
sl@0:  * protocol, and it is not a correct solution.
sl@0:  *
sl@0:  * <p>In the future we may revisit the UnicodeMatcher / UnicodeFilter
sl@0:  * hierarchy and either redesign it, or simply remove the stubs in
sl@0:  * UnicodeFilter and force subclasses to implement the full
sl@0:  * UnicodeMatcher protocol.
sl@0:  *
sl@0:  * @see UnicodeFilterLogic
sl@0:  * @stable ICU 2.0
sl@0:  */
sl@0: class U_COMMON_API UnicodeFilter : public UnicodeFunctor, public UnicodeMatcher {
sl@0: 
sl@0: public:
sl@0:     /**
sl@0:      * Destructor
sl@0:      * @stable ICU 2.0
sl@0:      */
sl@0:     virtual ~UnicodeFilter();
sl@0: 
sl@0:     /**
sl@0:      * Returns <tt>true</tt> for characters that are in the selected
sl@0:      * subset.  In other words, if a character is <b>to be
sl@0:      * filtered</b>, then <tt>contains()</tt> returns
sl@0:      * <b><tt>false</tt></b>.
sl@0:      * @stable ICU 2.0
sl@0:      */
sl@0:     virtual UBool contains(UChar32 c) const = 0;
sl@0: 
sl@0:     /**
sl@0:      * UnicodeFunctor API.  Cast 'this' to a UnicodeMatcher* pointer
sl@0:      * and return the pointer.
sl@0:      * @stable ICU 2.4
sl@0:      */
sl@0:     virtual UnicodeMatcher* toMatcher() const;
sl@0: 
sl@0:     /**
sl@0:      * Implement UnicodeMatcher API.
sl@0:      * @stable ICU 2.4
sl@0:      */
sl@0:     virtual UMatchDegree matches(const Replaceable& text,
sl@0:                                  int32_t& offset,
sl@0:                                  int32_t limit,
sl@0:                                  UBool incremental);
sl@0: 
sl@0:     /**
sl@0:      * UnicodeFunctor API.  Nothing to do.
sl@0:      * @stable ICU 2.4
sl@0:      */
sl@0:     virtual void setData(const TransliterationRuleData*);
sl@0: 
sl@0:     /**
sl@0:      * ICU "poor man's RTTI", returns a UClassID for the actual class.
sl@0:      *
sl@0:      * @stable ICU 2.2
sl@0:      */
sl@0:     virtual UClassID getDynamicClassID() const = 0;
sl@0: 
sl@0:     /**
sl@0:      * ICU "poor man's RTTI", returns a UClassID for this class.
sl@0:      *
sl@0:      * @stable ICU 2.2
sl@0:      */
sl@0:     static UClassID U_EXPORT2 getStaticClassID();
sl@0: 
sl@0: protected:
sl@0: 
sl@0:     /*
sl@0:      * Since this class has pure virtual functions,
sl@0:      * a constructor can't be used.
sl@0:      * @stable ICU 2.0
sl@0:      */
sl@0: /*    UnicodeFilter();*/
sl@0: };
sl@0: 
sl@0: /*inline UnicodeFilter::UnicodeFilter() {}*/
sl@0: 
sl@0: U_NAMESPACE_END
sl@0: 
sl@0: #endif