1/*
2*******************************************************************************
3* Copyright (C) 2012-2014, International Business Machines
4* Corporation and others.  All Rights Reserved.
5*******************************************************************************
6* utf8collationiterator.h
7*
8* created on: 2012nov12 (from utf16collationiterator.h & uitercollationiterator.h)
9* created by: Markus W. Scherer
10*/
11
12#ifndef __UTF8COLLATIONITERATOR_H__
13#define __UTF8COLLATIONITERATOR_H__
14
15#include "unicode/utypes.h"
16
17#if !UCONFIG_NO_COLLATION
18
19#include "cmemory.h"
20#include "collation.h"
21#include "collationdata.h"
22#include "normalizer2impl.h"
23
24U_NAMESPACE_BEGIN
25
26/**
27 * UTF-8 collation element and character iterator.
28 * Handles normalized UTF-8 text inline, with length or NUL-terminated.
29 * Unnormalized text is handled by a subclass.
30 */
31class U_I18N_API UTF8CollationIterator : public CollationIterator {
32public:
33    UTF8CollationIterator(const CollationData *d, UBool numeric,
34                          const uint8_t *s, int32_t p, int32_t len)
35            : CollationIterator(d, numeric),
36              u8(s), pos(p), length(len) {}
37
38    virtual ~UTF8CollationIterator();
39
40    virtual void resetToOffset(int32_t newOffset);
41
42    virtual int32_t getOffset() const;
43
44    virtual UChar32 nextCodePoint(UErrorCode &errorCode);
45
46    virtual UChar32 previousCodePoint(UErrorCode &errorCode);
47
48protected:
49    /**
50     * For byte sequences that are illegal in UTF-8, an error value may be returned
51     * together with a bogus code point. The caller will ignore that code point.
52     *
53     * Special values may be returned for surrogate code points, which are also illegal in UTF-8,
54     * but the caller will treat them like U+FFFD because forbidSurrogateCodePoints() returns TRUE.
55     *
56     * Valid lead surrogates are returned from inside a normalized text segment,
57     * where handleGetTrailSurrogate() will return the matching trail surrogate.
58     */
59    virtual uint32_t handleNextCE32(UChar32 &c, UErrorCode &errorCode);
60
61    virtual UBool foundNULTerminator();
62
63    virtual UBool forbidSurrogateCodePoints() const;
64
65    virtual void forwardNumCodePoints(int32_t num, UErrorCode &errorCode);
66
67    virtual void backwardNumCodePoints(int32_t num, UErrorCode &errorCode);
68
69    const uint8_t *u8;
70    int32_t pos;
71    int32_t length;  // <0 for NUL-terminated strings
72};
73
74/**
75 * Incrementally checks the input text for FCD and normalizes where necessary.
76 */
77class U_I18N_API FCDUTF8CollationIterator : public UTF8CollationIterator {
78public:
79    FCDUTF8CollationIterator(const CollationData *data, UBool numeric,
80                             const uint8_t *s, int32_t p, int32_t len)
81            : UTF8CollationIterator(data, numeric, s, p, len),
82              state(CHECK_FWD), start(p),
83              nfcImpl(data->nfcImpl) {}
84
85    virtual ~FCDUTF8CollationIterator();
86
87    virtual void resetToOffset(int32_t newOffset);
88
89    virtual int32_t getOffset() const;
90
91    virtual UChar32 nextCodePoint(UErrorCode &errorCode);
92
93    virtual UChar32 previousCodePoint(UErrorCode &errorCode);
94
95protected:
96    virtual uint32_t handleNextCE32(UChar32 &c, UErrorCode &errorCode);
97
98    virtual UChar handleGetTrailSurrogate();
99
100    virtual UBool foundNULTerminator();
101
102    virtual void forwardNumCodePoints(int32_t num, UErrorCode &errorCode);
103
104    virtual void backwardNumCodePoints(int32_t num, UErrorCode &errorCode);
105
106private:
107    UBool nextHasLccc() const;
108    UBool previousHasTccc() const;
109
110    /**
111     * Switches to forward checking if possible.
112     */
113    void switchToForward();
114
115    /**
116     * Extends the FCD text segment forward or normalizes around pos.
117     * @return TRUE if success
118     */
119    UBool nextSegment(UErrorCode &errorCode);
120
121    /**
122     * Switches to backward checking.
123     */
124    void switchToBackward();
125
126    /**
127     * Extends the FCD text segment backward or normalizes around pos.
128     * @return TRUE if success
129     */
130    UBool previousSegment(UErrorCode &errorCode);
131
132    UBool normalize(const UnicodeString &s, UErrorCode &errorCode);
133
134    enum State {
135        /**
136         * The input text [start..pos[ passes the FCD check.
137         * Moving forward checks incrementally.
138         * limit is undefined.
139         */
140        CHECK_FWD,
141        /**
142         * The input text [pos..limit[ passes the FCD check.
143         * Moving backward checks incrementally.
144         * start is undefined.
145         */
146        CHECK_BWD,
147        /**
148         * The input text [start..limit[ passes the FCD check.
149         * pos tracks the current text index.
150         */
151        IN_FCD_SEGMENT,
152        /**
153         * The input text [start..limit[ failed the FCD check and was normalized.
154         * pos tracks the current index in the normalized string.
155         */
156        IN_NORMALIZED
157    };
158
159    State state;
160
161    int32_t start;
162    int32_t limit;
163
164    const Normalizer2Impl &nfcImpl;
165    UnicodeString normalized;
166};
167
168U_NAMESPACE_END
169
170#endif  // !UCONFIG_NO_COLLATION
171#endif  // __UTF8COLLATIONITERATOR_H__
172