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

     2 // All rights reserved.

     3 // This component and the accompanying materials are made available

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

     5 // which accompanies this distribution, and is available

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

     7 //

     8 // Initial Contributors:

     9 // Nokia Corporation - initial contribution.

    10 //

    11 // Contributors:

    12 //

    13 // Description:

    14 // dictionarycompression.h

    15 //

    16 /** 

    17 * @file dictionarycompression.h

    18 *

    19 * @internalComponent

    20 * @released

    21 */

    22 #if !defined(__DICTIONARYCOMPRESSION_H__)

    23 #define __DICTIONARYCOMPRESSION_H__

    24 

    25 #include <string>

    26 #include "commontypes.h"

    27 #include <cassert>

    28 

    29 /**

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

    31 @internalComponent

    32 */

    33 class RDictionaryCompressionBitStream

    34 	{

    35 public:

    36 	RDictionaryCompressionBitStream();

    37 	void OpenL(

    38 		TInt aNumberOfBitsUsedForDictionaryTokens,

    39 		TInt aOffsetToFirstBit,

    40 		TInt aOffsetOnePastLastBit,

    41 		TBool aTransferringOwnershipOfBuffer,

    42 		TUint8* aBuffer);

    43 	void Close();

    44 	TBool EndOfStreamL() const;

    45 	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

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

    47 private:

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

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

    50 private:

    51 	TInt iNumberOfBitsUsedForDictionaryTokens;

    52 	TInt iOffsetToFirstBit;

    53 	TInt iOffsetToCurrentBit;

    54 	TInt iOffsetOnePastLastBit;

    55 	TBool iOwnsBitBuffer;

    56 	TUint8* iBuffer;

    57 	};

    58 

    59 #endif

    60