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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 *******************************************************************************
      5 * Copyright (C) 2012-2016, International Business Machines
      6 * Corporation and others.  All Rights Reserved.
      7 *******************************************************************************
      8 * utf8collationiterator.h
      9 *
     10 * created on: 2012nov12 (from utf16collationiterator.h & uitercollationiterator.h)
     11 * created by: Markus W. Scherer
     12 */
     13 
     14 #ifndef __UTF8COLLATIONITERATOR_H__
     15 #define __UTF8COLLATIONITERATOR_H__
     16 
     17 #include "unicode/utypes.h"
     18 
     19 #if !UCONFIG_NO_COLLATION
     20 
     21 #include "cmemory.h"
     22 #include "collation.h"
     23 #include "collationdata.h"
     24 #include "collationiterator.h"
     25 #include "normalizer2impl.h"
     26 
     27 U_NAMESPACE_BEGIN
     28 
     29 /**
     30  * UTF-8 collation element and character iterator.
     31  * Handles normalized UTF-8 text inline, with length or NUL-terminated.
     32  * Unnormalized text is handled by a subclass.
     33  */
     34 class U_I18N_API UTF8CollationIterator : public CollationIterator {
     35 public:
     36     UTF8CollationIterator(const CollationData *d, UBool numeric,
     37                           const uint8_t *s, int32_t p, int32_t len)
     38             : CollationIterator(d, numeric),
     39               u8(s), pos(p), length(len) {}
     40 
     41     virtual ~UTF8CollationIterator();
     42 
     43     virtual void resetToOffset(int32_t newOffset);
     44 
     45     virtual int32_t getOffset() const;
     46 
     47     virtual UChar32 nextCodePoint(UErrorCode &errorCode);
     48 
     49     virtual UChar32 previousCodePoint(UErrorCode &errorCode);
     50 
     51 protected:
     52     /**
     53      * For byte sequences that are illegal in UTF-8, an error value may be returned
     54      * together with a bogus code point. The caller will ignore that code point.
     55      *
     56      * Special values may be returned for surrogate code points, which are also illegal in UTF-8,
     57      * but the caller will treat them like U+FFFD because forbidSurrogateCodePoints() returns TRUE.
     58      *
     59      * Valid lead surrogates are returned from inside a normalized text segment,
     60      * where handleGetTrailSurrogate() will return the matching trail surrogate.
     61      */
     62     virtual uint32_t handleNextCE32(UChar32 &c, UErrorCode &errorCode);
     63 
     64     virtual UBool foundNULTerminator();
     65 
     66     virtual UBool forbidSurrogateCodePoints() const;
     67 
     68     virtual void forwardNumCodePoints(int32_t num, UErrorCode &errorCode);
     69 
     70     virtual void backwardNumCodePoints(int32_t num, UErrorCode &errorCode);
     71 
     72     const uint8_t *u8;
     73     int32_t pos;
     74     int32_t length;  // <0 for NUL-terminated strings
     75 };
     76 
     77 /**
     78  * Incrementally checks the input text for FCD and normalizes where necessary.
     79  */
     80 class U_I18N_API FCDUTF8CollationIterator : public UTF8CollationIterator {
     81 public:
     82     FCDUTF8CollationIterator(const CollationData *data, UBool numeric,
     83                              const uint8_t *s, int32_t p, int32_t len)
     84             : UTF8CollationIterator(data, numeric, s, p, len),
     85               state(CHECK_FWD), start(p),
     86               nfcImpl(data->nfcImpl) {}
     87 
     88     virtual ~FCDUTF8CollationIterator();
     89 
     90     virtual void resetToOffset(int32_t newOffset);
     91 
     92     virtual int32_t getOffset() const;
     93 
     94     virtual UChar32 nextCodePoint(UErrorCode &errorCode);
     95 
     96     virtual UChar32 previousCodePoint(UErrorCode &errorCode);
     97 
     98 protected:
     99     virtual uint32_t handleNextCE32(UChar32 &c, UErrorCode &errorCode);
    100 
    101     virtual UChar handleGetTrailSurrogate();
    102 
    103     virtual UBool foundNULTerminator();
    104 
    105     virtual void forwardNumCodePoints(int32_t num, UErrorCode &errorCode);
    106 
    107     virtual void backwardNumCodePoints(int32_t num, UErrorCode &errorCode);
    108 
    109 private:
    110     UBool nextHasLccc() const;
    111     UBool previousHasTccc() const;
    112 
    113     /**
    114      * Switches to forward checking if possible.
    115      */
    116     void switchToForward();
    117 
    118     /**
    119      * Extends the FCD text segment forward or normalizes around pos.
    120      * @return TRUE if success
    121      */
    122     UBool nextSegment(UErrorCode &errorCode);
    123 
    124     /**
    125      * Switches to backward checking.
    126      */
    127     void switchToBackward();
    128 
    129     /**
    130      * Extends the FCD text segment backward or normalizes around pos.
    131      * @return TRUE if success
    132      */
    133     UBool previousSegment(UErrorCode &errorCode);
    134 
    135     UBool normalize(const UnicodeString &s, UErrorCode &errorCode);
    136 
    137     enum State {
    138         /**
    139          * The input text [start..pos[ passes the FCD check.
    140          * Moving forward checks incrementally.
    141          * limit is undefined.
    142          */
    143         CHECK_FWD,
    144         /**
    145          * The input text [pos..limit[ passes the FCD check.
    146          * Moving backward checks incrementally.
    147          * start is undefined.
    148          */
    149         CHECK_BWD,
    150         /**
    151          * The input text [start..limit[ passes the FCD check.
    152          * pos tracks the current text index.
    153          */
    154         IN_FCD_SEGMENT,
    155         /**
    156          * The input text [start..limit[ failed the FCD check and was normalized.
    157          * pos tracks the current index in the normalized string.
    158          */
    159         IN_NORMALIZED
    160     };
    161 
    162     State state;
    163 
    164     int32_t start;
    165     int32_t limit;
    166 
    167     const Normalizer2Impl &nfcImpl;
    168     UnicodeString normalized;
    169 };
    170 
    171 U_NAMESPACE_END
    172 
    173 #endif  // !UCONFIG_NO_COLLATION
    174 #endif  // __UTF8COLLATIONITERATOR_H__
    175