os/textandloc/fontservices/textshaperplugin/IcuSource/common/unicode/unimatch.h
author sl
Tue, 10 Jun 2014 14:32:02 +0200
changeset 1 260cb5ec6c19
permissions -rw-r--r--
Update contrib.
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/*
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* Copyright (C) 2001-2005, International Business Machines Corporation and others. All Rights Reserved.
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**********************************************************************
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*   Date        Name        Description
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*   07/18/01    aliu        Creation.
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**********************************************************************
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*/
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#ifndef UNIMATCH_H
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#define UNIMATCH_H
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#include "unicode/utypes.h"
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/**
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 * \file 
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 * \brief C++ API: Unicode Matcher
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 */
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U_NAMESPACE_BEGIN
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class Replaceable;
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class UnicodeString;
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class UnicodeSet;
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/**
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 * Constants returned by <code>UnicodeMatcher::matches()</code>
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 * indicating the degree of match.
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 * @stable ICU 2.4
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 */
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enum UMatchDegree {
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    /**
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     * Constant returned by <code>matches()</code> indicating a
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     * mismatch between the text and this matcher.  The text contains
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     * a character which does not match, or the text does not contain
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     * all desired characters for a non-incremental match.
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     * @stable ICU 2.4
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     */
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    U_MISMATCH,
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    /**
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     * Constant returned by <code>matches()</code> indicating a
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     * partial match between the text and this matcher.  This value is
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     * only returned for incremental match operations.  All characters
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     * of the text match, but more characters are required for a
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     * complete match.  Alternatively, for variable-length matchers,
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     * all characters of the text match, and if more characters were
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     * supplied at limit, they might also match.
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     * @stable ICU 2.4
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     */
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    U_PARTIAL_MATCH,
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    /**
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     * Constant returned by <code>matches()</code> indicating a
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     * complete match between the text and this matcher.  For an
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     * incremental variable-length match, this value is returned if
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     * the given text matches, and it is known that additional
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     * characters would not alter the extent of the match.
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     * @stable ICU 2.4
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     */
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    U_MATCH
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};
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/**
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 * <code>UnicodeMatcher</code> defines a protocol for objects that can
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 * match a range of characters in a Replaceable string.
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 * @stable ICU 2.4
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 */
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class U_COMMON_API UnicodeMatcher /* not : public UObject because this is an interface/mixin class */ {
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public:
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    /**
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     * Destructor.
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     * @stable ICU 2.4
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     */
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    virtual ~UnicodeMatcher();
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    /**
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     * Return a UMatchDegree value indicating the degree of match for
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     * the given text at the given offset.  Zero, one, or more
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     * characters may be matched.
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     *
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     * Matching in the forward direction is indicated by limit >
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     * offset.  Characters from offset forwards to limit-1 will be
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     * considered for matching.
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     * 
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     * Matching in the reverse direction is indicated by limit <
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     * offset.  Characters from offset backwards to limit+1 will be
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     * considered for matching.
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     *
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     * If limit == offset then the only match possible is a zero
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     * character match (which subclasses may implement if desired).
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     *
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     * As a side effect, advance the offset parameter to the limit of
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     * the matched substring.  In the forward direction, this will be
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     * the index of the last matched character plus one.  In the
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     * reverse direction, this will be the index of the last matched
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     * character minus one.
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     *
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     * <p>Note:  This method is not const because some classes may
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     * modify their state as the result of a match.
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     *
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     * @param text the text to be matched
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     * @param offset on input, the index into text at which to begin
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     * matching.  On output, the limit of the matched text.  The
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     * number of matched characters is the output value of offset
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     * minus the input value.  Offset should always point to the
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     * HIGH SURROGATE (leading code unit) of a pair of surrogates,
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     * both on entry and upon return.
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     * @param limit the limit index of text to be matched.  Greater
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     * than offset for a forward direction match, less than offset for
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     * a backward direction match.  The last character to be
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     * considered for matching will be text.charAt(limit-1) in the
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     * forward direction or text.charAt(limit+1) in the backward
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     * direction.
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     * @param incremental if TRUE, then assume further characters may
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     * be inserted at limit and check for partial matching.  Otherwise
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     * assume the text as given is complete.
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     * @return a match degree value indicating a full match, a partial
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     * match, or a mismatch.  If incremental is FALSE then
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     * U_PARTIAL_MATCH should never be returned.
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     * @stable ICU 2.4
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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) = 0;
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    /**
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     * Returns a string representation of this matcher.  If the result of
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     * calling this function is passed to the appropriate parser, it
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     * will produce another matcher that is equal to this one.
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     * @param result the string to receive the pattern.  Previous
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     * contents will be deleted.
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     * @param escapeUnprintable if TRUE then convert unprintable
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     * character to their hex escape representations, \\uxxxx or
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     * \\Uxxxxxxxx.  Unprintable characters are those other than
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     * U+000A, U+0020..U+007E.
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     * @stable ICU 2.4
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     */
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    virtual UnicodeString& toPattern(UnicodeString& result,
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                                     UBool escapeUnprintable = FALSE) const = 0;
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    /**
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     * Returns TRUE if this matcher will match a character c, where c
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     * & 0xFF == v, at offset, in the forward direction (with limit >
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     * offset).  This is used by <tt>RuleBasedTransliterator</tt> for
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     * indexing.
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     * @stable ICU 2.4
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     */
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    virtual UBool matchesIndexValue(uint8_t v) const = 0;
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    /**
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     * Union the set of all characters that may be matched by this object
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     * into the given set.
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     * @param toUnionTo the set into which to union the source characters
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     * @stable ICU 2.4
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     */
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    virtual void addMatchSetTo(UnicodeSet& toUnionTo) const = 0;
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};
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U_NAMESPACE_END
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#endif