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// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
**********************************************************************
* Copyright (C) 1999-2010, International Business Machines Corporation and others.
* All Rights Reserved.
**********************************************************************
* Date Name Description
* 11/17/99 aliu Creation.
**********************************************************************
*/
#ifndef UNIFILT_H
#define UNIFILT_H
#include "unicode/unifunct.h"
#include "unicode/unimatch.h"
/**
* \file
* \brief C++ API: Unicode Filter
*/
U_NAMESPACE_BEGIN
/**
* U_ETHER is used to represent character values for positions outside
* a range. For example, transliterator uses this to represent
* characters outside the range contextStart..contextLimit-1. This
* allows explicit matching by rules and UnicodeSets of text outside a
* defined range.
* @stable ICU 3.0
*/
#define U_ETHER ((char16_t)0xFFFF)
/**
*
* <code>UnicodeFilter</code> defines a protocol for selecting a
* subset of the full range (U+0000 to U+10FFFF) of Unicode characters.
* Currently, filters are used in conjunction with classes like {@link
* Transliterator} to only process selected characters through a
* transformation.
*
* <p>Note: UnicodeFilter currently stubs out two pure virtual methods
* of its base class, UnicodeMatcher. These methods are toPattern()
* and matchesIndexValue(). This is done so that filter classes that
* are not actually used as matchers -- specifically, those in the
* UnicodeFilterLogic component, and those in tests -- can continue to
* work without defining these methods. As long as a filter is not
* used in an RBT during real transliteration, these methods will not
* be called. However, this breaks the UnicodeMatcher base class
* protocol, and it is not a correct solution.
*
* <p>In the future we may revisit the UnicodeMatcher / UnicodeFilter
* hierarchy and either redesign it, or simply remove the stubs in
* UnicodeFilter and force subclasses to implement the full
* UnicodeMatcher protocol.
*
* @see UnicodeFilterLogic
* @stable ICU 2.0
*/
class U_COMMON_API UnicodeFilter : public UnicodeFunctor, public UnicodeMatcher {
public:
/**
* Destructor
* @stable ICU 2.0
*/
virtual ~UnicodeFilter();
/**
* Returns <tt>true</tt> for characters that are in the selected
* subset. In other words, if a character is <b>to be
* filtered</b>, then <tt>contains()</tt> returns
* <b><tt>false</tt></b>.
* @stable ICU 2.0
*/
virtual UBool contains(UChar32 c) const = 0;
/**
* UnicodeFunctor API. Cast 'this' to a UnicodeMatcher* pointer
* and return the pointer.
* @stable ICU 2.4
*/
virtual UnicodeMatcher* toMatcher() const;
/**
* Implement UnicodeMatcher API.
* @stable ICU 2.4
*/
virtual UMatchDegree matches(const Replaceable& text,
int32_t& offset,
int32_t limit,
UBool incremental);
/**
* UnicodeFunctor API. Nothing to do.
* @stable ICU 2.4
*/
virtual void setData(const TransliterationRuleData*);
/**
* ICU "poor man's RTTI", returns a UClassID for this class.
*
* @stable ICU 2.2
*/
static UClassID U_EXPORT2 getStaticClassID();
protected:
/*
* Since this class has pure virtual functions,
* a constructor can't be used.
* @stable ICU 2.0
*/
/* UnicodeFilter();*/
};
/*inline UnicodeFilter::UnicodeFilter() {}*/
U_NAMESPACE_END
#endif