codekingpro/portable-devtools

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#if U_SHOW_CPLUSPLUS_API
21
22U_NAMESPACE_BEGIN
23
24class Replaceable;
25class UnicodeString;
26class UnicodeSet;
27
28/**
29 * Constants returned by <code>UnicodeMatcher::matches()</code>
30 * indicating the degree of match.
31 * @stable ICU 2.4
32 */
33enum UMatchDegree {
34    /**
35     * Constant returned by <code>matches()</code> indicating a
36     * mismatch between the text and this matcher.  The text contains
37     * a character which does not match, or the text does not contain
38     * all desired characters for a non-incremental match.
39     * @stable ICU 2.4
40     */
41    U_MISMATCH,
42    
43    /**
44     * Constant returned by <code>matches()</code> indicating a
45     * partial match between the text and this matcher.  This value is
46     * only returned for incremental match operations.  All characters
47     * of the text match, but more characters are required for a
48     * complete match.  Alternatively, for variable-length matchers,
49     * all characters of the text match, and if more characters were
50     * supplied at limit, they might also match.
51     * @stable ICU 2.4
52     */
53    U_PARTIAL_MATCH,
54    
55    /**
56     * Constant returned by <code>matches()</code> indicating a
57     * complete match between the text and this matcher.  For an
58     * incremental variable-length match, this value is returned if
59     * the given text matches, and it is known that additional
60     * characters would not alter the extent of the match.
61     * @stable ICU 2.4
62     */
63    U_MATCH
64};
65
66/**
67 * <code>UnicodeMatcher</code> defines a protocol for objects that can
68 * match a range of characters in a Replaceable string.
69 * @stable ICU 2.4
70 */
71class U_COMMON_API UnicodeMatcher /* not : public UObject because this is an interface/mixin class */ {
72
73public:
74    /**
75     * Destructor.
76     * @stable ICU 2.4
77     */
78    virtual ~UnicodeMatcher();
79
80    /**
81     * Return a UMatchDegree value indicating the degree of match for
82     * the given text at the given offset.  Zero, one, or more
83     * characters may be matched.
84     *
85     * Matching in the forward direction is indicated by limit >
86     * offset.  Characters from offset forwards to limit-1 will be
87     * considered for matching.
88     * 
89     * Matching in the reverse direction is indicated by limit <
90     * offset.  Characters from offset backwards to limit+1 will be
91     * considered for matching.
92     *
93     * If limit == offset then the only match possible is a zero
94     * character match (which subclasses may implement if desired).
95     *
96     * As a side effect, advance the offset parameter to the limit of
97     * the matched substring.  In the forward direction, this will be
98     * the index of the last matched character plus one.  In the
99     * reverse direction, this will be the index of the last matched
100     * character minus one.
101     *
102     * <p>Note:  This method is not const because some classes may
103     * modify their state as the result of a match.
104     *
105     * @param text the text to be matched
106     * @param offset on input, the index into text at which to begin
107     * matching.  On output, the limit of the matched text.  The
108     * number of matched characters is the output value of offset
109     * minus the input value.  Offset should always point to the
110     * HIGH SURROGATE (leading code unit) of a pair of surrogates,
111     * both on entry and upon return.
112     * @param limit the limit index of text to be matched.  Greater
113     * than offset for a forward direction match, less than offset for
114     * a backward direction match.  The last character to be
115     * considered for matching will be text.charAt(limit-1) in the
116     * forward direction or text.charAt(limit+1) in the backward
117     * direction.
118     * @param incremental if TRUE, then assume further characters may
119     * be inserted at limit and check for partial matching.  Otherwise
120     * assume the text as given is complete.
121     * @return a match degree value indicating a full match, a partial
122     * match, or a mismatch.  If incremental is FALSE then
123     * U_PARTIAL_MATCH should never be returned.
124     * @stable ICU 2.4
125     */
126    virtual UMatchDegree matches(const Replaceable& text,
127                                 int32_t& offset,
128                                 int32_t limit,
129                                 UBool incremental) = 0;
130
131    /**
132     * Returns a string representation of this matcher.  If the result of
133     * calling this function is passed to the appropriate parser, it
134     * will produce another matcher that is equal to this one.
135     * @param result the string to receive the pattern.  Previous
136     * contents will be deleted.
137     * @param escapeUnprintable if TRUE then convert unprintable
138     * character to their hex escape representations, \\uxxxx or
139     * \\Uxxxxxxxx.  Unprintable characters are those other than
140     * U+000A, U+0020..U+007E.
141     * @stable ICU 2.4
142     */
143    virtual UnicodeString& toPattern(UnicodeString& result,
144                                     UBool escapeUnprintable = FALSE) const = 0;
145
146    /**
147     * Returns TRUE if this matcher will match a character c, where c
148     * & 0xFF == v, at offset, in the forward direction (with limit >
149     * offset).  This is used by <tt>RuleBasedTransliterator</tt> for
150     * indexing.
151     * @stable ICU 2.4
152     */
153    virtual UBool matchesIndexValue(uint8_t v) const = 0;
154
155    /**
156     * Union the set of all characters that may be matched by this object
157     * into the given set.
158     * @param toUnionTo the set into which to union the source characters
159     * @stable ICU 2.4
160     */
161    virtual void addMatchSetTo(UnicodeSet& toUnionTo) const = 0;
162};
163
164U_NAMESPACE_END
165
166#endif /* U_SHOW_CPLUSPLUS_API */
167
168#endif
169