1// © 2016 and later: Unicode, Inc. and others.
2// License & terms of use: http://www.unicode.org/copyright.html
3/*
4**********************************************************************
5* Copyright (c) 2001-2012, International Business Machines
6* Corporation and others.  All Rights Reserved.
7**********************************************************************
8*   Date        Name        Description
9*   07/18/01    aliu        Creation.
10**********************************************************************
11*/
12
13#include "unicode/unifilt.h"
14#include "unicode/rep.h"
15#include "unicode/utf16.h"
16
17U_NAMESPACE_BEGIN
18UOBJECT_DEFINE_ABSTRACT_RTTI_IMPLEMENTATION(UnicodeFilter)
19
20
21/* Define this here due to the lack of another file.
22   It can't be defined in the header */
23UnicodeMatcher::~UnicodeMatcher() {}
24
25UnicodeFilter::~UnicodeFilter() {}
26
27/**
28 * UnicodeFunctor API.
29 *   Note that UnicodeMatcher is a base class of UnicodeFilter.
30 */
31UnicodeMatcher* UnicodeFilter::toMatcher() const {
32  return const_cast<UnicodeFilter *>(this);
33}
34
35void UnicodeFilter::setData(const TransliterationRuleData*) {}
36
37/**
38 * Default implementation of UnicodeMatcher::matches() for Unicode
39 * filters.  Matches a single code point at offset (either one or
40 * two 16-bit code units).
41 */
42UMatchDegree UnicodeFilter::matches(const Replaceable& text,
43                                    int32_t& offset,
44                                    int32_t limit,
45                                    UBool incremental) {
46    UChar32 c;
47    if (offset < limit &&
48        contains(c = text.char32At(offset))) {
49        offset += U16_LENGTH(c);
50        return U_MATCH;
51    }
52    if (offset > limit &&
53        contains(c = text.char32At(offset))) {
54        // Backup offset by 1, unless the preceding character is a
55        // surrogate pair -- then backup by 2 (keep offset pointing at
56        // the lead surrogate).
57        --offset;
58        if (offset >= 0) {
59            offset -= U16_LENGTH(text.char32At(offset)) - 1;
60        }
61        return U_MATCH;
62    }
63    if (incremental && offset == limit) {
64        return U_PARTIAL_MATCH;
65    }
66    return U_MISMATCH;
67}
68
69U_NAMESPACE_END
70
71//eof
72