// Copyright (c) 2002-2009 Nokia Corporation and/or its subsidiary(-ies).

// All rights reserved.

// This component and the accompanying materials are made available

// under the terms of the License "Symbian Foundation License v1.0"

// which accompanies this distribution, and is available

// at the URL "http://www.symbianfoundation.org/legal/sfl-v10.html".

//

// Initial Contributors:

// Nokia Corporation - initial contribution.

//

// Contributors:

//

// Description:

// Folding and decomposition implementation

// 

//

#ifndef __COMPAREIMP_H__

#define __COMPAREIMP_H__

#include <e32std.h>

#include <unicode.h>

//Forward declarations

class TUTF32Iterator;

//////////////////////////////////////////////////////////////////////////////////////////////

// Global functions

//////////////////////////////////////////////////////////////////////////////////////////////

TChar UTF16ToChar(const TText16* a);

TBool IsBaseCharacter(TChar);

TBool MatchSectionFolded(TUTF32Iterator& aCandidateString, TUTF32Iterator& aSearchTerm);

TBool FindMatchSectionFolded(TUTF32Iterator& aCandidateString, TUTF32Iterator& aSearchTerm);

TBool MatchStringFolded(const TText16* aCandidateStringStart, const TText16* aCandidateStringEnd,

                        const TText16* aSearchTermStart, const TText16* aSearchTermEnd);

TInt LocateMatchStringFolded(const TText16* aCandidateStringStart, const TText16* aCandidateStringEnd,

                             const TText16* aSearchTermStart, const TText16* aSearchTermEnd);

TInt FindFolded(TUTF32Iterator& aCandidateString, TUTF32Iterator& aSearchTerm);

TInt CompareFolded(const TUTF32Iterator& aLeft, const TUTF32Iterator& aRight);

TInt CombineAsMuchAsPossible(const TDesC16& aDes, TChar& aCombined);

TBool DecomposeChar(TChar aCh, TPtrC16& aResult);

inline void SkipCombiningCharacters(TUTF32Iterator& aUTF32It);

/**

Converts UTF16 into UTF32, ignoring non-characters and

unpaired surrogates and combining paired surrogates.

@internalComponent

*/

class TUTF32Iterator

	{

public:

	enum TStartsWithValidCharacter { EStartsWithValidCharacter };

	inline TUTF32Iterator();

	inline explicit TUTF32Iterator(const TText16* aSingleton);

	inline TUTF32Iterator(const TText16* aStart, const TText16* aEnd);

	inline TUTF32Iterator(const TText16* aStart, const TText16* aEnd, TStartsWithValidCharacter);

	inline TUTF32Iterator CurrentAsIterator() const;

	inline TBool AtEnd() const;

	void Next();

	inline TChar Current() const;

	TBool LocateFoldedBaseCharacter(TChar aChar);

	inline const TText16* CurrentPosition() const;

	inline TInt Length() const;

	inline TInt operator[](TInt) const;

	inline void SetStart(const TText16*);

private:

	const TText16* iStart;

	const TText16* iEnd;

	TChar iCurrent;

	};

//////////////////////////////////////////////////////////////////////////////////////////////

// FOLDING

//////////////////////////////////////////////////////////////////////////////////////////////

/**

@internalComponent

*/

class TFoldedDecompIterator

	{

public:

	inline TFoldedDecompIterator();

	explicit TFoldedDecompIterator(const TUTF32Iterator&);

	inline void Set(const TUTF32Iterator&);

	TBool AtEnd() const;

	TBool AtEndOrWildcard() const;

	TBool EnterFoldedSequence();

	TBool StrictEnterFoldedSequence();

	inline TBool IsInFoldedSequence() const;

	TBool CurrentIsBaseFoldedFromCombiner() const;

	TChar Current() const;

	TBool Match(TChar aCode);

	TBool Match(TFoldedDecompIterator& aThat);

	void Next();

	inline TUTF32Iterator BaseIterator() const;

private:

	TUTF32Iterator iOriginal;

	TUTF32Iterator iFolded;

	};

/**

Sorts sequences of combining characters with non-zero combining classes into

order of their combining classes.

@internalComponent

*/

class TFoldedSortedDecompIterator

	{

public:

	inline TFoldedSortedDecompIterator();

	TInt Set(TFoldedDecompIterator &aBase);

	void Set();

	TBool AtEnd() const;

	TChar Current() const;

	void Next();

private:

	TFoldedDecompIterator iStart; // Starting code.	

	TInt iLength; // Length in decomposed codes.

	TFoldedDecompIterator iCurrent; // Current code.

	TInt iCurrentCount; // Number of decomposed codes iCurrent is past iStart

	TInt iCurrentClass; // Current class being searched for.

	TInt iRemaining; // Number of Next()s left

	};

/**

Iterator that outputs canonically decomposed folded strings.

This is much slower than using the matching functions, so should only

be used where an ordering is required.

@internalComponent

*/

class TFoldedCanonicalIterator

	{

public:

	TFoldedCanonicalIterator(const TUTF32Iterator&);

	TBool AtEnd() const;

	TChar Current() const;

	void Next(const TUnicodeDataSet* aCharDataSet);

private:

	TFoldedDecompIterator iBase;

	TFoldedSortedDecompIterator iSorted;

	};

//////////////////////////////////////////////////////////////////////////////////////////////

// COLLATION

//////////////////////////////////////////////////////////////////////////////////////////////

/**

@internalComponent

*/

class TDecompositionIterator

	{

public:

	inline TDecompositionIterator();

	void Set(const TUTF32Iterator&);

	explicit TDecompositionIterator(const TUTF32Iterator&);

	TBool AtEnd() const;

	TChar Current() const;

	void Next();

	const TText16* CurrentPosition() const;

private:

	TUTF32Iterator iBase;

	TUTF32Iterator iDecomposition;

	};

/**

@internalComponent

*/

class TCanonicalDecompositionIterator

	{

public:

	inline TCanonicalDecompositionIterator();

	void Set(const TUTF32Iterator&);

	TBool AtEnd() const;

	TChar Current() const;

	void Next();

	const TText16* CurrentPositionIfAtCharacter() const;

	TBool IsInOpenSequence() const;

private:

	TDecompositionIterator iBase;

	// iBase.CurrentPosition() before the last move

	const TText16* iLastPosition;

	// If iCurrent is active, iCurrentCombiningClass

	// is nonzero, and represents the combining class

	// of the character it points to.

	TInt iCurrentCombiningClass;

	// contains true if more characters added to the end may change

	// the characters currently being output

	TBool iInOpenSequence;

	// Iterator that looks for characters to be sorted.

	TDecompositionIterator iCurrent;

	};

/**

Iterator that gives the canonically decomposed form of

its input, and allows a limited amount of look-ahead (i.e.

peeking further into the decomposition without moving

the iterator)

@internalComponent

*/

class TCanonicalDecompositionIteratorCached

	{

public:

	void Set(const TUTF32Iterator&);

	TBool AtEnd() const;

	// Advance aOffset characters.

	void Next(TInt aOffset);

	// Get the character at the position of the iterator plus aOffset steps.

	// Returns FFFF if we are looking too far ahead.

	TChar Get(TInt aOffset);

	// If the current position in the original string is representable

	// as a pointer into it and we know what it is, return it.

	const TText16* CurrentPositionIfAtCharacter() const;

private:

	// KMaxLookAhead must be a power of 2

	enum { KMaxLookAhead = 8 };

	TCanonicalDecompositionIterator iBase;

	struct TCache

		{

		TChar iChar;

		const TText16* iPos;

		};

	TCache iCache[KMaxLookAhead + 1];

	TInt iCacheStart;

	TInt iCacheSize;

	};

#include "compareimp.inl"

#endif //__COMPAREIMP_H__