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1 : // © 2016 and later: Unicode, Inc. and others.
2 : // License & terms of use: http://www.unicode.org/copyright.html
3 : /*
4 : * Copyright (C) 2001-2005, International Business Machines Corporation and others. All Rights Reserved.
5 : **********************************************************************
6 : * Date Name Description
7 : * 07/18/01 aliu Creation.
8 : **********************************************************************
9 : */
10 : #ifndef UNIMATCH_H
11 : #define UNIMATCH_H
12 :
13 : #include "unicode/utypes.h"
14 :
15 : /**
16 : * \file
17 : * \brief C++ API: Unicode Matcher
18 : */
19 :
20 :
21 : U_NAMESPACE_BEGIN
22 :
23 : class Replaceable;
24 : class UnicodeString;
25 : class UnicodeSet;
26 :
27 : /**
28 : * Constants returned by <code>UnicodeMatcher::matches()</code>
29 : * indicating the degree of match.
30 : * @stable ICU 2.4
31 : */
32 : enum UMatchDegree {
33 : /**
34 : * Constant returned by <code>matches()</code> indicating a
35 : * mismatch between the text and this matcher. The text contains
36 : * a character which does not match, or the text does not contain
37 : * all desired characters for a non-incremental match.
38 : * @stable ICU 2.4
39 : */
40 : U_MISMATCH,
41 :
42 : /**
43 : * Constant returned by <code>matches()</code> indicating a
44 : * partial match between the text and this matcher. This value is
45 : * only returned for incremental match operations. All characters
46 : * of the text match, but more characters are required for a
47 : * complete match. Alternatively, for variable-length matchers,
48 : * all characters of the text match, and if more characters were
49 : * supplied at limit, they might also match.
50 : * @stable ICU 2.4
51 : */
52 : U_PARTIAL_MATCH,
53 :
54 : /**
55 : * Constant returned by <code>matches()</code> indicating a
56 : * complete match between the text and this matcher. For an
57 : * incremental variable-length match, this value is returned if
58 : * the given text matches, and it is known that additional
59 : * characters would not alter the extent of the match.
60 : * @stable ICU 2.4
61 : */
62 : U_MATCH
63 : };
64 :
65 : /**
66 : * <code>UnicodeMatcher</code> defines a protocol for objects that can
67 : * match a range of characters in a Replaceable string.
68 : * @stable ICU 2.4
69 : */
70 0 : class U_COMMON_API UnicodeMatcher /* not : public UObject because this is an interface/mixin class */ {
71 :
72 : public:
73 : /**
74 : * Destructor.
75 : * @stable ICU 2.4
76 : */
77 : virtual ~UnicodeMatcher();
78 :
79 : /**
80 : * Return a UMatchDegree value indicating the degree of match for
81 : * the given text at the given offset. Zero, one, or more
82 : * characters may be matched.
83 : *
84 : * Matching in the forward direction is indicated by limit >
85 : * offset. Characters from offset forwards to limit-1 will be
86 : * considered for matching.
87 : *
88 : * Matching in the reverse direction is indicated by limit <
89 : * offset. Characters from offset backwards to limit+1 will be
90 : * considered for matching.
91 : *
92 : * If limit == offset then the only match possible is a zero
93 : * character match (which subclasses may implement if desired).
94 : *
95 : * As a side effect, advance the offset parameter to the limit of
96 : * the matched substring. In the forward direction, this will be
97 : * the index of the last matched character plus one. In the
98 : * reverse direction, this will be the index of the last matched
99 : * character minus one.
100 : *
101 : * <p>Note: This method is not const because some classes may
102 : * modify their state as the result of a match.
103 : *
104 : * @param text the text to be matched
105 : * @param offset on input, the index into text at which to begin
106 : * matching. On output, the limit of the matched text. The
107 : * number of matched characters is the output value of offset
108 : * minus the input value. Offset should always point to the
109 : * HIGH SURROGATE (leading code unit) of a pair of surrogates,
110 : * both on entry and upon return.
111 : * @param limit the limit index of text to be matched. Greater
112 : * than offset for a forward direction match, less than offset for
113 : * a backward direction match. The last character to be
114 : * considered for matching will be text.charAt(limit-1) in the
115 : * forward direction or text.charAt(limit+1) in the backward
116 : * direction.
117 : * @param incremental if TRUE, then assume further characters may
118 : * be inserted at limit and check for partial matching. Otherwise
119 : * assume the text as given is complete.
120 : * @return a match degree value indicating a full match, a partial
121 : * match, or a mismatch. If incremental is FALSE then
122 : * U_PARTIAL_MATCH should never be returned.
123 : * @stable ICU 2.4
124 : */
125 : virtual UMatchDegree matches(const Replaceable& text,
126 : int32_t& offset,
127 : int32_t limit,
128 : UBool incremental) = 0;
129 :
130 : /**
131 : * Returns a string representation of this matcher. If the result of
132 : * calling this function is passed to the appropriate parser, it
133 : * will produce another matcher that is equal to this one.
134 : * @param result the string to receive the pattern. Previous
135 : * contents will be deleted.
136 : * @param escapeUnprintable if TRUE then convert unprintable
137 : * character to their hex escape representations, \\uxxxx or
138 : * \\Uxxxxxxxx. Unprintable characters are those other than
139 : * U+000A, U+0020..U+007E.
140 : * @stable ICU 2.4
141 : */
142 : virtual UnicodeString& toPattern(UnicodeString& result,
143 : UBool escapeUnprintable = FALSE) const = 0;
144 :
145 : /**
146 : * Returns TRUE if this matcher will match a character c, where c
147 : * & 0xFF == v, at offset, in the forward direction (with limit >
148 : * offset). This is used by <tt>RuleBasedTransliterator</tt> for
149 : * indexing.
150 : * @stable ICU 2.4
151 : */
152 : virtual UBool matchesIndexValue(uint8_t v) const = 0;
153 :
154 : /**
155 : * Union the set of all characters that may be matched by this object
156 : * into the given set.
157 : * @param toUnionTo the set into which to union the source characters
158 : * @stable ICU 2.4
159 : */
160 : virtual void addMatchSetTo(UnicodeSet& toUnionTo) const = 0;
161 : };
162 :
163 : U_NAMESPACE_END
164 :
165 : #endif
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