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// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html 
/* 
******************************************************************************* 
* Copyright (C) 2012-2016, International Business Machines 
* Corporation and others.  All Rights Reserved. 
******************************************************************************* 
* utf8collationiterator.h 
* 
* created on: 2012nov12 (from utf16collationiterator.h & uitercollationiterator.h) 
* created by: Markus W. Scherer 
*/ 
 
#ifndef __UTF8COLLATIONITERATOR_H__ 
#define __UTF8COLLATIONITERATOR_H__ 
 
#include "unicode/utypes.h" 
 
#if !UCONFIG_NO_COLLATION 
 
#include "cmemory.h" 
#include "collation.h" 
#include "collationdata.h" 
#include "collationiterator.h" 
#include "normalizer2impl.h" 
 
U_NAMESPACE_BEGIN 
 
/** 
 * UTF-8 collation element and character iterator. 
 * Handles normalized UTF-8 text inline, with length or NUL-terminated. 
 * Unnormalized text is handled by a subclass. 
 */ 
class U_I18N_API UTF8CollationIterator : public CollationIterator { 
public: 
    UTF8CollationIterator(const CollationData *d, UBool numeric, 
                          const uint8_t *s, int32_t p, int32_t len) 
            : CollationIterator(d, numeric), 
              u8(s), pos(p), length(len) {} 
 
    virtual ~UTF8CollationIterator(); 
 
    virtual void resetToOffset(int32_t newOffset); 
 
    virtual int32_t getOffset() const; 
 
    virtual UChar32 nextCodePoint(UErrorCode &errorCode); 
 
    virtual UChar32 previousCodePoint(UErrorCode &errorCode); 
 
protected: 
    /** 
     * For byte sequences that are illegal in UTF-8, an error value may be returned 
     * together with a bogus code point. The caller will ignore that code point. 
     * 
     * Special values may be returned for surrogate code points, which are also illegal in UTF-8, 
     * but the caller will treat them like U+FFFD because forbidSurrogateCodePoints() returns TRUE. 
     * 
     * Valid lead surrogates are returned from inside a normalized text segment, 
     * where handleGetTrailSurrogate() will return the matching trail surrogate. 
     */ 
    virtual uint32_t handleNextCE32(UChar32 &c, UErrorCode &errorCode); 
 
    virtual UBool foundNULTerminator(); 
 
    virtual UBool forbidSurrogateCodePoints() const; 
 
    virtual void forwardNumCodePoints(int32_t num, UErrorCode &errorCode); 
 
    virtual void backwardNumCodePoints(int32_t num, UErrorCode &errorCode); 
 
    const uint8_t *u8; 
    int32_t pos; 
    int32_t length;  // <0 for NUL-terminated strings 
}; 
 
/** 
 * Incrementally checks the input text for FCD and normalizes where necessary. 
 */ 
class U_I18N_API FCDUTF8CollationIterator : public UTF8CollationIterator { 
public: 
    FCDUTF8CollationIterator(const CollationData *data, UBool numeric, 
                             const uint8_t *s, int32_t p, int32_t len) 
            : UTF8CollationIterator(data, numeric, s, p, len), 
              state(CHECK_FWD), start(p), 
              nfcImpl(data->nfcImpl) {} 
 
    virtual ~FCDUTF8CollationIterator(); 
 
    virtual void resetToOffset(int32_t newOffset); 
 
    virtual int32_t getOffset() const; 
 
    virtual UChar32 nextCodePoint(UErrorCode &errorCode); 
 
    virtual UChar32 previousCodePoint(UErrorCode &errorCode); 
 
protected: 
    virtual uint32_t handleNextCE32(UChar32 &c, UErrorCode &errorCode); 
 
    virtual UChar handleGetTrailSurrogate(); 
 
    virtual UBool foundNULTerminator(); 
 
    virtual void forwardNumCodePoints(int32_t num, UErrorCode &errorCode); 
 
    virtual void backwardNumCodePoints(int32_t num, UErrorCode &errorCode); 
 
private: 
    UBool nextHasLccc() const; 
    UBool previousHasTccc() const; 
 
    /** 
     * Switches to forward checking if possible. 
     */ 
    void switchToForward(); 
 
    /** 
     * Extends the FCD text segment forward or normalizes around pos. 
     * @return TRUE if success 
     */ 
    UBool nextSegment(UErrorCode &errorCode); 
 
    /** 
     * Switches to backward checking. 
     */ 
    void switchToBackward(); 
 
    /** 
     * Extends the FCD text segment backward or normalizes around pos. 
     * @return TRUE if success 
     */ 
    UBool previousSegment(UErrorCode &errorCode); 
 
    UBool normalize(const UnicodeString &s, UErrorCode &errorCode); 
 
    enum State { 
        /** 
         * The input text [start..pos[ passes the FCD check. 
         * Moving forward checks incrementally. 
         * limit is undefined. 
         */ 
        CHECK_FWD, 
        /** 
         * The input text [pos..limit[ passes the FCD check. 
         * Moving backward checks incrementally. 
         * start is undefined. 
         */ 
        CHECK_BWD, 
        /** 
         * The input text [start..limit[ passes the FCD check. 
         * pos tracks the current text index. 
         */ 
        IN_FCD_SEGMENT, 
        /** 
         * The input text [start..limit[ failed the FCD check and was normalized. 
         * pos tracks the current index in the normalized string. 
         */ 
        IN_NORMALIZED 
    }; 
 
    State state; 
 
    int32_t start; 
    int32_t limit; 
 
    const Normalizer2Impl &nfcImpl; 
    UnicodeString normalized; 
}; 
 
U_NAMESPACE_END 
 
#endif  // !UCONFIG_NO_COLLATION 
#endif  // __UTF8COLLATIONITERATOR_H__