138 lines
4.1 KiB
C++
138 lines
4.1 KiB
C++
/*
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* Copyright (C) 1999, International Business Machines Corporation and others. All Rights Reserved.
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**********************************************************************
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* Date Name Description
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* 11/17/99 aliu Creation.
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**********************************************************************
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*/
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#ifndef UNIFILT_H
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#define UNIFILT_H
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#include "unicode/unifunct.h"
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#include "unicode/unimatch.h"
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U_NAMESPACE_BEGIN
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/**
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* U_ETHER is used to represent character values for positions outside
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* a range. For example, transliterator uses this to represent
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* characters outside the range contextStart..contextLimit-1. This
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* allows explicit matching by rules and UnicodeSets of text outside a
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* defined range.
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*/
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#define U_ETHER ((UChar)0xFFFF)
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/**
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* <code>UnicodeFilter</code> defines a protocol for selecting a
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* subset of the full range (U+0000 to U+10FFFF) of Unicode characters.
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* Currently, filters are used in conjunction with classes like {@link
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* Transliterator} to only process selected characters through a
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* transformation.
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*
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* <p>Note: UnicodeFilter currently stubs out two pure virtual methods
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* of its base class, UnicodeMatcher. These methods are toPattern()
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* and matchesIndexValue(). This is done so that filter classes that
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* are not actually used as matchers -- specifically, those in the
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* UnicodeFilterLogic component, and those in tests -- can continue to
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* work without defining these methods. As long as a filter is not
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* used in an RBT during real transliteration, these methods will not
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* be called. However, this breaks the UnicodeMatcher base class
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* protocol, and it is not a correct solution.
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*
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* <p>In the future we may revisit the UnicodeMatcher / UnicodeFilter
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* hierarchy and either redesign it, or simply remove the stubs in
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* UnicodeFilter and force subclasses to implement the full
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* UnicodeMatcher protocol.
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*
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* @see UnicodeFilterLogic
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* @stable
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*/
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class U_COMMON_API UnicodeFilter : public UnicodeFunctor, public UnicodeMatcher {
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public:
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/**
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* Destructor
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* @stable
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*/
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virtual ~UnicodeFilter();
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/**
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* Returns <tt>true</tt> for characters that are in the selected
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* subset. In other words, if a character is <b>to be
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* filtered</b>, then <tt>contains()</tt> returns
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* <b><tt>false</tt></b>.
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* @stable
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*/
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virtual UBool contains(UChar32 c) const = 0;
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/**
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* UnicodeFunctor API. Cast 'this' to a UnicodeMatcher* pointer
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* and return the pointer.
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*/
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virtual UnicodeMatcher* toMatcher() const;
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/**
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* UnicodeMatcher API. This class stubs this out.
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*/
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UnicodeString& toPattern(UnicodeString& result,
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UBool escapeUnprintable) const;
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/**
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* UnicodeMatcher API. This class stubs this out.
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*/
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UBool matchesIndexValue(uint8_t v) const;
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/**
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* Implement UnicodeMatcher API.
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*/
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virtual UMatchDegree matches(const Replaceable& text,
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int32_t& offset,
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int32_t limit,
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UBool incremental);
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/**
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* UnicodeFunctor API. Nothing to do.
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*/
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virtual void setData(const TransliterationRuleData*) {}
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/**
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* ICU "poor man's RTTI", returns a UClassID for the actual class.
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*
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* @draft ICU 2.2
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*/
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virtual inline UClassID getDynamicClassID() const { return getStaticClassID(); }
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/**
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* ICU "poor man's RTTI", returns a UClassID for this class.
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*
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* @draft ICU 2.2
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*/
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static inline UClassID getStaticClassID() { return (UClassID)&fgClassID; }
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/**
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* Stubbed out implementation of UnicodeMatcher API.
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* @param toUnionTo the set into which to union the source characters
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* @return a reference to toUnionTo
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*/
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virtual void addMatchSetTo(UnicodeSet& toUnionTo) const;
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protected:
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UnicodeFilter();
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private:
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/**
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* The address of this static class variable serves as this class's ID
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* for ICU "poor man's RTTI".
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*/
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static const char fgClassID;
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};
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inline UnicodeFilter::UnicodeFilter() {}
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inline UnicodeFilter::~UnicodeFilter() {}
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U_NAMESPACE_END
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#endif
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