1 // Copyright (c) 2001-2009 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 //

    15 

    16 #if !defined(__E32STD_H__)

    17 #include <e32std.h>

    18 #endif

    19 

    20 #if !defined(__BADICTIONARYCOMPRESSION_H__)

    21 #define __BADICTIONARYCOMPRESSION_H__

    22 

    23 #include "BaAssert.h"

    24 

    25 /**

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

    27 @internalComponent

    28 */

    29 class RDictionaryCompressionBitStream

    30 	{

    31 public:

    32 	RDictionaryCompressionBitStream();

    33 	void OpenL(

    34 		TInt aNumberOfBitsUsedForDictionaryTokens,

    35 		TInt aOffsetToFirstBit,

    36 		TInt aOffsetOnePastLastBit,

    37 		TBool aTransferringOwnershipOfBuffer,

    38 		TUint8* aBuffer,

    39 		const TBaAssert& aAssertObj);

    40 	void Close();

    41 	TBool EndOfStreamL() const;

    42 	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

    43  	void ReadL(TDes8& aBufferToAppendTo,TBool aCalypsoFileFormat); // can only be called if IndexOfDictionaryEntry returned a negative value

    44 private:

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

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

    47 private:

    48 	TInt iNumberOfBitsUsedForDictionaryTokens;

    49 	TInt iOffsetToFirstBit;

    50 	TInt iOffsetToCurrentBit;

    51 	TInt iOffsetOnePastLastBit;

    52 	TBool iOwnsBitBuffer;

    53 	TUint8* iBuffer;

    54 	TBaAssert iAssertObj;

    55 	};

    56 

    57 #endif

    58