icuSources/i18n/utf8collationiterator.h

   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
  24 U_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  */
  31 class U_I18N_API UTF8CollationIterator : public CollationIterator {
  32 public:
  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
  48 protected:
  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  */
  77 class U_I18N_API FCDUTF8CollationIterator : public UTF8CollationIterator {
  78 public:
  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
  95 protected:
  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
 106 private:
 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
 168 U_NAMESPACE_END
 169
 170 #endif  // !UCONFIG_NO_COLLATION
 171 #endif  // __UTF8COLLATIONITERATOR_H__