icuSources/common/unicode/unifilt.h

   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 #if U_SHOW_CPLUSPLUS_API
  24 U_NAMESPACE_BEGIN
  25
  26 /**
  27  * U_ETHER is used to represent character values for positions outside
  28  * a range.  For example, transliterator uses this to represent
  29  * characters outside the range contextStart..contextLimit-1.  This
  30  * allows explicit matching by rules and UnicodeSets of text outside a
  31  * defined range.
  32  * @stable ICU 3.0
  33  */
  34 #define U_ETHER ((char16_t)0xFFFF)
  35
  36 /**
  37  *
  38  * <code>UnicodeFilter</code> defines a protocol for selecting a
  39  * subset of the full range (U+0000 to U+10FFFF) of Unicode characters.
  40  * Currently, filters are used in conjunction with classes like {@link
  41  * Transliterator} to only process selected characters through a
  42  * transformation.
  43  *
  44  * <p>Note: UnicodeFilter currently stubs out two pure virtual methods
  45  * of its base class, UnicodeMatcher.  These methods are toPattern()
  46  * and matchesIndexValue().  This is done so that filter classes that
  47  * are not actually used as matchers -- specifically, those in the
  48  * UnicodeFilterLogic component, and those in tests -- can continue to
  49  * work without defining these methods.  As long as a filter is not
  50  * used in an RBT during real transliteration, these methods will not
  51  * be called.  However, this breaks the UnicodeMatcher base class
  52  * protocol, and it is not a correct solution.
  53  *
  54  * <p>In the future we may revisit the UnicodeMatcher / UnicodeFilter
  55  * hierarchy and either redesign it, or simply remove the stubs in
  56  * UnicodeFilter and force subclasses to implement the full
  57  * UnicodeMatcher protocol.
  58  *
  59  * @see UnicodeFilterLogic
  60  * @stable ICU 2.0
  61  */
  62 class U_COMMON_API UnicodeFilter : public UnicodeFunctor, public UnicodeMatcher {
  63
  64 public:
  65     /**
  66      * Destructor
  67      * @stable ICU 2.0
  68      */
  69     virtual ~UnicodeFilter();
  70
  71     /**
  72      * Returns <tt>true</tt> for characters that are in the selected
  73      * subset.  In other words, if a character is <b>to be
  74      * filtered</b>, then <tt>contains()</tt> returns
  75      * <b><tt>false</tt></b>.
  76      * @stable ICU 2.0
  77      */
  78     virtual UBool contains(UChar32 c) const = 0;
  79
  80     /**
  81      * UnicodeFunctor API.  Cast 'this' to a UnicodeMatcher* pointer
  82      * and return the pointer.
  83      * @stable ICU 2.4
  84      */
  85     virtual UnicodeMatcher* toMatcher() const;
  86
  87     /**
  88      * Implement UnicodeMatcher API.
  89      * @stable ICU 2.4
  90      */
  91     virtual UMatchDegree matches(const Replaceable& text,
  92                                  int32_t& offset,
  93                                  int32_t limit,
  94                                  UBool incremental);
  95
  96     /**
  97      * UnicodeFunctor API.  Nothing to do.
  98      * @stable ICU 2.4
  99      */
 100     virtual void setData(const TransliterationRuleData*);
 101
 102     /**
 103      * ICU "poor man's RTTI", returns a UClassID for this class.
 104      *
 105      * @stable ICU 2.2
 106      */
 107     static UClassID U_EXPORT2 getStaticClassID();
 108
 109 protected:
 110
 111     /*
 112      * Since this class has pure virtual functions,
 113      * a constructor can't be used.
 114      * @stable ICU 2.0
 115      */
 116 /*    UnicodeFilter();*/
 117 };
 118
 119 /*inline UnicodeFilter::UnicodeFilter() {}*/
 120
 121 U_NAMESPACE_END
 122 #endif // U_SHOW_CPLUSPLUS_API
 123
 124 #endif