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/*
* Copyright (C) 2001, International Business Machines Corporation and others. All Rights Reserved.
**********************************************************************
* Date Name Description
* 07/18/01 aliu Creation.
**********************************************************************
*/
#ifndef UNIMATCH_H
#define UNIMATCH_H
#include "unicode/utypes.h"
U_NAMESPACE_BEGIN
class Replaceable;
class UnicodeString;
class UnicodeSet;
/**
* Constants returned by <code>UnicodeMatcher::matches()</code>
* indicating the degree of match.
* @draft ICU 2.4
*/
enum UMatchDegree {
/**
* Constant returned by <code>matches()</code> indicating a
* mismatch between the text and this matcher. The text contains
* a character which does not match, or the text does not contain
* all desired characters for a non-incremental match.
* @draft ICU 2.4
*/
U_MISMATCH,
/**
* Constant returned by <code>matches()</code> indicating a
* partial match between the text and this matcher. This value is
* only returned for incremental match operations. All characters
* of the text match, but more characters are required for a
* complete match. Alternatively, for variable-length matchers,
* all characters of the text match, and if more characters were
* supplied at limit, they might also match.
* @draft ICU 2.4
*/
U_PARTIAL_MATCH,
/**
* Constant returned by <code>matches()</code> indicating a
* complete match between the text and this matcher. For an
* incremental variable-length match, this value is returned if
* the given text matches, and it is known that additional
* characters would not alter the extent of the match.
* @draft ICU 2.4
*/
U_MATCH
};
/**
* <code>UnicodeMatcher</code> defines a protocol for objects that can
* match a range of characters in a Replaceable string.
* @draft ICU 2.4
*/
class U_COMMON_API UnicodeMatcher /* not : public UObject because this is an interface/mixin class */ {
public:
/**
* Destructor.
* @draft ICU 2.4
*/
virtual ~UnicodeMatcher();
/**
* Return a UMatchDegree value indicating the degree of match for
* the given text at the given offset. Zero, one, or more
* characters may be matched.
*
* Matching in the forward direction is indicated by limit >
* offset. Characters from offset forwards to limit-1 will be
* considered for matching.
*
* Matching in the reverse direction is indicated by limit <
* offset. Characters from offset backwards to limit+1 will be
* considered for matching.
*
* If limit == offset then the only match possible is a zero
* character match (which subclasses may implement if desired).
*
* As a side effect, advance the offset parameter to the limit of
* the matched substring. In the forward direction, this will be
* the index of the last matched character plus one. In the
* reverse direction, this will be the index of the last matched
* character minus one.
*
* <p>Note: This method is not const because some classes may
* modify their state as the result of a match.
*
* @param text the text to be matched
* @param offset on input, the index into text at which to begin
* matching. On output, the limit of the matched text. The
* number of matched characters is the output value of offset
* minus the input value. Offset should always point to the
* HIGH SURROGATE (leading code unit) of a pair of surrogates,
* both on entry and upon return.
* @param limit the limit index of text to be matched. Greater
* than offset for a forward direction match, less than offset for
* a backward direction match. The last character to be
* considered for matching will be text.charAt(limit-1) in the
* forward direction or text.charAt(limit+1) in the backward
* direction.
* @param incremental if TRUE, then assume further characters may
* be inserted at limit and check for partial matching. Otherwise
* assume the text as given is complete.
* @return a match degree value indicating a full match, a partial
* match, or a mismatch. If incremental is FALSE then
* U_PARTIAL_MATCH should never be returned.
* @draft ICU 2.4
*/
virtual UMatchDegree matches(const Replaceable& text,
int32_t& offset,
int32_t limit,
UBool incremental) = 0;
/**
* Returns a string representation of this matcher. If the result of
* calling this function is passed to the appropriate parser, it
* will produce another matcher that is equal to this one.
* @param result the string to receive the pattern. Previous
* contents will be deleted.
* @param escapeUnprintable if TRUE then convert unprintable
* character to their hex escape representations, \uxxxx or
* \Uxxxxxxxx. Unprintable characters are those other than
* U+000A, U+0020..U+007E.
* @draft ICU 2.4
*/
virtual UnicodeString& toPattern(UnicodeString& result,
UBool escapeUnprintable = FALSE) const = 0;
/**
* Returns TRUE if this matcher will match a character c, where c
* & 0xFF == v, at offset, in the forward direction (with limit >
* offset). This is used by <tt>RuleBasedTransliterator</tt> for
* indexing.
* @draft ICU 2.4
*/
virtual UBool matchesIndexValue(uint8_t v) const = 0;
/**
* Union the set of all characters that may be matched by this object
* into the given set.
* @param toUnionTo the set into which to union the source characters
* @draft ICU 2.4
*/
virtual void addMatchSetTo(UnicodeSet& toUnionTo) const = 0;
};
U_NAMESPACE_END
#endif