// Copyright (c) 2010 Nokia Corporation and/or its subsidiary(-ies).

// All rights reserved.

// This component and the accompanying materials are made available

// under the terms of "Eclipse Public License v1.0"

// which accompanies this distribution, and is available

// at the URL "http://www.eclipse.org/legal/epl-v10.html".

//

// Initial Contributors:

// Nokia Corporation - initial contribution.

//

// Contributors:

//

// Description:

// dictionarycompression.h

//

/** 

* @file dictionarycompression.h

*

* @internalComponent

* @released

*/

#if !defined(__DICTIONARYCOMPRESSION_H__)

#define __DICTIONARYCOMPRESSION_H__

#include <string>

#include "commontypes.h"

#include <cassert>

/**

This class implements a stream of bits (least significant bit first) as used by the code reading dictionary-compressed resource-files

@internalComponent

*/

class RDictionaryCompressionBitStream

	{

public:

	RDictionaryCompressionBitStream();

	void OpenL(

		TInt aNumberOfBitsUsedForDictionaryTokens,

		TInt aOffsetToFirstBit,

		TInt aOffsetOnePastLastBit,

		TBool aTransferringOwnershipOfBuffer,

		TUint8* aBuffer);

	void Close();

	TBool EndOfStreamL() const;

	TInt IndexOfDictionaryEntryL(); // increments the current bit-position if it returns a value >=0; returns a negative value if the next thing in the stream is plain data rather than the index of a dictionary entry

 	void ReadL(Ptr8 aBufferToAppendTo,TBool aCalypsoFileFormat); // can only be called if IndexOfDictionaryEntry returned a negative value

private:

	TBool CurrentBitIsOn() const; // does not increment the current bit-position

	TUint ReadIntegerL(TInt aNumberOfBits); // increments the current bit-position

private:

	TInt iNumberOfBitsUsedForDictionaryTokens;

	TInt iOffsetToFirstBit;

	TInt iOffsetToCurrentBit;

	TInt iOffsetOnePastLastBit;

	TBool iOwnsBitBuffer;

	TUint8* iBuffer;

	};

#endif