summaryrefslogtreecommitdiff
path: root/thirdparty/icu4c/common/unicode/unimatch.h
blob: 302332f4558c3e06abb2e7b1fa3d043695e54cde (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/*
* Copyright (C) 2001-2005, 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"

/**
 * \file 
 * \brief C++ API: Unicode Matcher
 */

#if U_SHOW_CPLUSPLUS_API

U_NAMESPACE_BEGIN

class Replaceable;
class UnicodeString;
class UnicodeSet;

/**
 * Constants returned by <code>UnicodeMatcher::matches()</code>
 * indicating the degree of match.
 * @stable 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.
     * @stable 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.
     * @stable 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.
     * @stable ICU 2.4
     */
    U_MATCH
};

/**
 * <code>UnicodeMatcher</code> defines a protocol for objects that can
 * match a range of characters in a Replaceable string.
 * @stable ICU 2.4
 */
class U_COMMON_API UnicodeMatcher /* not : public UObject because this is an interface/mixin class */ {

public:
    /**
     * Destructor.
     * @stable 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.
     * @stable 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.
     * @stable 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.
     * @stable 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
     * @stable ICU 2.4
     */
    virtual void addMatchSetTo(UnicodeSet& toUnionTo) const = 0;
};

U_NAMESPACE_END

#endif /* U_SHOW_CPLUSPLUS_API */

#endif