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       1             : // © 2016 and later: Unicode, Inc. and others.
       2             : // License & terms of use: http://www.unicode.org/copyright.html
       3             : /*
       4             : **********************************************************************
       5             : * Copyright (C) 1999-2010, International Business Machines Corporation and others.
       6             : * All Rights Reserved.
       7             : **********************************************************************
       8             : *   Date        Name        Description
       9             : *   11/17/99    aliu        Creation.
      10             : **********************************************************************
      11             : */
      12             : #ifndef UNIFILT_H
      13             : #define UNIFILT_H
      14             : 
      15             : #include "unicode/unifunct.h"
      16             : #include "unicode/unimatch.h"
      17             : 
      18             : /**
      19             :  * \file 
      20             :  * \brief C++ API: Unicode Filter
      21             :  */
      22             : 
      23             : U_NAMESPACE_BEGIN
      24             : 
      25             : /**
      26             :  * U_ETHER is used to represent character values for positions outside
      27             :  * a range.  For example, transliterator uses this to represent
      28             :  * characters outside the range contextStart..contextLimit-1.  This
      29             :  * allows explicit matching by rules and UnicodeSets of text outside a
      30             :  * defined range.
      31             :  * @stable ICU 3.0
      32             :  */
      33             : #define U_ETHER ((char16_t)0xFFFF)
      34             : 
      35             : /**
      36             :  *
      37             :  * <code>UnicodeFilter</code> defines a protocol for selecting a
      38             :  * subset of the full range (U+0000 to U+10FFFF) of Unicode characters.
      39             :  * Currently, filters are used in conjunction with classes like {@link
      40             :  * Transliterator} to only process selected characters through a
      41             :  * transformation.
      42             :  *
      43             :  * <p>Note: UnicodeFilter currently stubs out two pure virtual methods
      44             :  * of its base class, UnicodeMatcher.  These methods are toPattern()
      45             :  * and matchesIndexValue().  This is done so that filter classes that
      46             :  * are not actually used as matchers -- specifically, those in the
      47             :  * UnicodeFilterLogic component, and those in tests -- can continue to
      48             :  * work without defining these methods.  As long as a filter is not
      49             :  * used in an RBT during real transliteration, these methods will not
      50             :  * be called.  However, this breaks the UnicodeMatcher base class
      51             :  * protocol, and it is not a correct solution.
      52             :  *
      53             :  * <p>In the future we may revisit the UnicodeMatcher / UnicodeFilter
      54             :  * hierarchy and either redesign it, or simply remove the stubs in
      55             :  * UnicodeFilter and force subclasses to implement the full
      56             :  * UnicodeMatcher protocol.
      57             :  *
      58             :  * @see UnicodeFilterLogic
      59             :  * @stable ICU 2.0
      60             :  */
      61           0 : class U_COMMON_API UnicodeFilter : public UnicodeFunctor, public UnicodeMatcher {
      62             : 
      63             : public:
      64             :     /**
      65             :      * Destructor
      66             :      * @stable ICU 2.0
      67             :      */
      68             :     virtual ~UnicodeFilter();
      69             : 
      70             :     /**
      71             :      * Returns <tt>true</tt> for characters that are in the selected
      72             :      * subset.  In other words, if a character is <b>to be
      73             :      * filtered</b>, then <tt>contains()</tt> returns
      74             :      * <b><tt>false</tt></b>.
      75             :      * @stable ICU 2.0
      76             :      */
      77             :     virtual UBool contains(UChar32 c) const = 0;
      78             : 
      79             :     /**
      80             :      * UnicodeFunctor API.  Cast 'this' to a UnicodeMatcher* pointer
      81             :      * and return the pointer.
      82             :      * @stable ICU 2.4
      83             :      */
      84             :     virtual UnicodeMatcher* toMatcher() const;
      85             : 
      86             :     /**
      87             :      * Implement UnicodeMatcher API.
      88             :      * @stable ICU 2.4
      89             :      */
      90             :     virtual UMatchDegree matches(const Replaceable& text,
      91             :                                  int32_t& offset,
      92             :                                  int32_t limit,
      93             :                                  UBool incremental);
      94             : 
      95             :     /**
      96             :      * UnicodeFunctor API.  Nothing to do.
      97             :      * @stable ICU 2.4
      98             :      */
      99             :     virtual void setData(const TransliterationRuleData*);
     100             : 
     101             :     /**
     102             :      * ICU "poor man's RTTI", returns a UClassID for this class.
     103             :      *
     104             :      * @stable ICU 2.2
     105             :      */
     106             :     static UClassID U_EXPORT2 getStaticClassID();
     107             : 
     108             : protected:
     109             : 
     110             :     /*
     111             :      * Since this class has pure virtual functions,
     112             :      * a constructor can't be used.
     113             :      * @stable ICU 2.0
     114             :      */
     115             : /*    UnicodeFilter();*/
     116             : };
     117             : 
     118             : /*inline UnicodeFilter::UnicodeFilter() {}*/
     119             : 
     120             : U_NAMESPACE_END
     121             : 
     122             : #endif