sl@0: // Copyright (c) 1999-2009 Nokia Corporation and/or its subsidiary(-ies).
sl@0: // All rights reserved.
sl@0: // This component and the accompanying materials are made available
sl@0: // under the terms of "Eclipse Public License v1.0"
sl@0: // which accompanies this distribution, and is available
sl@0: // at the URL "http://www.eclipse.org/legal/epl-v10.html".
sl@0: //
sl@0: // Initial Contributors:
sl@0: // Nokia Corporation - initial contribution.
sl@0: //
sl@0: // Contributors:
sl@0: //
sl@0: // Description:
sl@0: // Declaration for Compression class
sl@0: // 
sl@0: //
sl@0: 
sl@0: #ifndef __EZCOMPRESSOR_H__
sl@0: #define __EZCOMPRESSOR_H__
sl@0: 
sl@0: #include <e32base.h>
sl@0: #include <ezstream.h>
sl@0: #include <ezbufman.h>
sl@0: 
sl@0: /**
sl@0: The CEZCompressor class provides in-memory compression functions, including integrity checks of the uncompressed data.
sl@0: This version of the library supports only one compression method (deflation).  Compression can be done in a single step
sl@0: (using CompressL()) if the buffers are large enough (for example if an input file is mmap'ed), or can be done by repeated calls
sl@0: of the DeflateL() function.  The source data is compressed to the target buffer (both source and target contained within 
sl@0: the buffer manager argument), and various other arguments distinguish the different compression settings.
sl@0: 
sl@0: Note: In this version of the library a windowBits value of 8 is unsupported due to a problem with the window size being 
sl@0: set to 256 bytes. Although a value of 8 will be accepted by the CEZCompressor constructors, as it is being changed 
sl@0: internally by Zlib from 8 to 9, it will not be possible to use the same value for decompression. This is because the 
sl@0: Zlib functions called by the CEZDecompressor constructors do not make the same change internally and as a result a 
sl@0: KEZlibErrData is returned when calling InflateL(). It is therefore advised that for this version of the library 
sl@0: windowBits of 9 is used in place of 8.
sl@0: 
sl@0: @publishedAll
sl@0: @released
sl@0: */
sl@0: class CEZCompressor : public CEZZStream
sl@0: 	{
sl@0: public:
sl@0: 	/** Compression strategy - used to tune the compression algorithm */
sl@0: 	enum TStrategy
sl@0: 		{
sl@0: 		/** Use for normal data */		
sl@0: 		EDefaultStrategy = Z_DEFAULT_STRATEGY, 
sl@0: 		
sl@0: 		/** Use for data produced by a filter (or predictor) */
sl@0: 		EFiltered = Z_FILTERED, 
sl@0: 		
sl@0: 		/** Force Huffman encoding only (no string match) */
sl@0: 		EHuffmanOnly = Z_HUFFMAN_ONLY
sl@0: 		};
sl@0: 
sl@0: 	/** Compression levels */
sl@0: 	enum 
sl@0: 		{
sl@0: 		EDefaultCompression = Z_DEFAULT_COMPRESSION,
sl@0: 		ENoCompression = Z_NO_COMPRESSION,
sl@0: 		EBestSpeed = Z_BEST_SPEED,
sl@0: 		EBestCompression = Z_BEST_COMPRESSION
sl@0: 		};
sl@0: 
sl@0: 	/** Window Bits - the base two logarithm of the window size (the size of the history buffer) */
sl@0: 	enum
sl@0: 		{
sl@0: 		EMaxWBits = MAX_WBITS
sl@0: 		};
sl@0: 
sl@0: 	/** Memory level - specifies how much memory should be allocated for the internal compression state */
sl@0: 	enum
sl@0: 		{
sl@0: 		EDefMemLevel = MAX_MEM_LEVEL
sl@0: 		};
sl@0: 
sl@0: 	/** Compression panic values */
sl@0: 	enum
sl@0: 		{
sl@0: 		EDeflateInitlialiserError = EUnexpected + 1,
sl@0: 		EDeflateTerminated
sl@0: 		};
sl@0: 
sl@0: 	public:
sl@0: 		~CEZCompressor();
sl@0: 
sl@0: 		IMPORT_C static CEZCompressor* NewLC(MEZBufferManager& aInit, TInt aLevel = EDefaultCompression,
sl@0: 			TInt aWindowBits = EMaxWBits, TInt aMemLevel = EDefMemLevel, TStrategy aStrategy = EDefaultStrategy);
sl@0: 		IMPORT_C static CEZCompressor* NewL(MEZBufferManager& aInit, TInt aLevel = EDefaultCompression,
sl@0: 			TInt aWindowBits = EMaxWBits, TInt aMemLevel = EDefMemLevel, TStrategy aStrategy = EDefaultStrategy);
sl@0: 		IMPORT_C static CEZCompressor* NewLC(MEZBufferManager& aInit, const TDesC8 &aDictionary, 
sl@0: 			TInt aLevel = EDefaultCompression, TInt aWindowBits = EMaxWBits, TInt aMemLevel = EDefMemLevel, 
sl@0: 			TStrategy aStrategy = EDefaultStrategy);
sl@0: 		IMPORT_C static CEZCompressor* NewL(MEZBufferManager& aInit, const TDesC8 &aDictionary,  
sl@0: 			TInt aLevel = EDefaultCompression, TInt aWindowBits = EMaxWBits, TInt aMemLevel = EDefMemLevel, 
sl@0: 			TStrategy aStrategy = EDefaultStrategy);
sl@0: 
sl@0: 		IMPORT_C void ResetL(MEZBufferManager& aInit);
sl@0: 
sl@0: 		IMPORT_C TBool DeflateL();
sl@0: 
sl@0: 		IMPORT_C static void CompressL(TDes8 &aDestination, const TDesC8 &aSource, TInt aLevel = EDefaultCompression);
sl@0: 
sl@0: 	private:
sl@0: 		enum TDeflationState
sl@0: 			{
sl@0: 			ENoFlush,
sl@0: 			EFinish,
sl@0: 			EFinalize,
sl@0: 			ETerminated
sl@0: 			};
sl@0: 
sl@0: 	private:
sl@0: 		CEZCompressor(MEZBufferManager* aInit);
sl@0: 		void ConstructL(TInt aLevel, const TUint8* aDictionary, TInt aLength, TInt aWindowBits, TInt aMemLevel, TStrategy aStrategy);
sl@0: 		void ConstructL(TInt aLevel, TInt aWindowBits, TInt aMemLevel, TStrategy aStrategy);
sl@0: 
sl@0: 	private:
sl@0: 		MEZBufferManager* iBufferInit;
sl@0: 		TDeflationState iDeflationState;
sl@0: 	};
sl@0: 
sl@0: #endif
sl@0: 
sl@0: