1 ezcompressor.h

     1 // Copyright (c) 1999-2009 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 the License "Symbian Foundation License v1.0" to Symbian Foundation members and "Symbian Foundation End User License Agreement v1.0" to non-members

     5 // which accompanies this distribution, and is available

     6 // at the URL "http://www.symbianfoundation.org/legal/licencesv10.html".

     7 //

     8 // Initial Contributors:

     9 // Nokia Corporation - initial contribution.

    10 //

    11 // Contributors:

    12 //

    13 // Description:

    14 // EZLib: COMPRESSOR.H

    15 // Declaration for Compression class

    16 // 

    17 //

    18 

    19 #ifndef __EZCOMPRESSOR_H__

    20 #define __EZCOMPRESSOR_H__

    21 

    22 #include <e32base.h>

    23 #include <ezstream.h>

    24 #include <ezbufman.h>

    25 

    26 /**

    27 The CEZCompressor class provides in-memory compression functions, including integrity checks of the uncompressed data.

    28 This version of the library supports only one compression method (deflation).  Compression can be done in a single step

    29 (using CompressL()) if the buffers are large enough (for example if an input file is mmap'ed), or can be done by repeated calls

    30 of the DeflateL() function.  The source data is compressed to the target buffer (both source and target contained within 

    31 the buffer manager argument), and various other arguments distinguish the different compression settings.

    32 

    33 @publishedAll

    34 @released

    35 */

    36 class CEZCompressor : public CEZZStream

    37 	{

    38 public:

    39 	/** Compression strategy - used to tune the compression algorithm */

    40 	enum TStrategy

    41 		{

    42 		/** Use for normal data */		

    43 		EDefaultStrategy = Z_DEFAULT_STRATEGY, 

    44 		

    45 		/** Force Huffman encoding only (no string match) */

    46 		EFiltered = Z_FILTERED, 

    47 		

    48 		/** Use for data produced by a filter (or predictor) */

    49 		EHuffmanOnly = Z_HUFFMAN_ONLY

    50 		};

    51 

    52 	/** Compression levels */

    53 	enum 

    54 		{

    55 		EDefaultCompression = Z_DEFAULT_COMPRESSION,

    56 		ENoCompression = Z_NO_COMPRESSION,

    57 		EBestSpeed = Z_BEST_SPEED,

    58 		EBestCompression = Z_BEST_COMPRESSION

    59 		};

    60 

    61 	/** Window Bits - the base two logarithm of the window size (the size of the history buffer) */

    62 	enum

    63 		{

    64 		EMaxWBits = MAX_WBITS

    65 		};

    66 

    67 	/** Memory level - specifies how much memory should be allocated for the internal compression state */

    68 	enum

    69 		{

    70 		EDefMemLevel = MAX_MEM_LEVEL

    71 		};

    72 

    73 	/** Compression panic values */

    74 	enum

    75 		{

    76 		EDeflateInitlialiserError = EUnexpected + 1,

    77 		EDeflateTerminated

    78 		};

    79 

    80 	public:

    81 		~CEZCompressor();

    82 

    83 		IMPORT_C static CEZCompressor* NewLC(MEZBufferManager& aInit, TInt aLevel = EDefaultCompression,

    84 			TInt aWindowBits = EMaxWBits, TInt aMemLevel = EDefMemLevel, TStrategy aStrategy = EDefaultStrategy);

    85 		IMPORT_C static CEZCompressor* NewL(MEZBufferManager& aInit, TInt aLevel = EDefaultCompression,

    86 			TInt aWindowBits = EMaxWBits, TInt aMemLevel = EDefMemLevel, TStrategy aStrategy = EDefaultStrategy);

    87 		IMPORT_C static CEZCompressor* NewLC(MEZBufferManager& aInit, const TDesC8 &aDictionary, 

    88 			TInt aLevel = EDefaultCompression, TInt aWindowBits = EMaxWBits, TInt aMemLevel = EDefMemLevel, 

    89 			TStrategy aStrategy = EDefaultStrategy);

    90 		IMPORT_C static CEZCompressor* NewL(MEZBufferManager& aInit, const TDesC8 &aDictionary,  

    91 			TInt aLevel = EDefaultCompression, TInt aWindowBits = EMaxWBits, TInt aMemLevel = EDefMemLevel, 

    92 			TStrategy aStrategy = EDefaultStrategy);

    93 

    94 		IMPORT_C void ResetL(MEZBufferManager& aInit);

    95 

    96 		IMPORT_C TBool DeflateL();

    97 

    98 		IMPORT_C static void CompressL(TDes8 &aDestination, const TDesC8 &aSource, TInt aLevel = EDefaultCompression);

    99 

   100 	private:

   101 		enum TDeflationState

   102 			{

   103 			ENoFlush,

   104 			EFinish,

   105 			EFinalize,

   106 			ETerminated

   107 			};

   108 

   109 	private:

   110 		CEZCompressor(MEZBufferManager* aInit);

   111 		void ConstructL(TInt aLevel, const TUint8* aDictionary, TInt aLength, TInt aWindowBits, TInt aMemLevel, TStrategy aStrategy);

   112 		void ConstructL(TInt aLevel, TInt aWindowBits, TInt aMemLevel, TStrategy aStrategy);

   113 

   114 	private:

   115 		MEZBufferManager* iBufferInit;

   116 		TDeflationState iDeflationState;

   117 	};

   118 

   119 #endif