epoc32/include/ezdecompressor.h
author William Roberts <williamr@symbian.org>
Wed, 31 Mar 2010 12:33:34 +0100 (2010-03-31)
branchSymbian3
changeset 4 837f303aceeb
parent 2 2fe1408b6811
permissions -rw-r--r--
Current Symbian^3 public API header files (from PDK 3.0.h)
This is the epoc32/include tree with the "platform" subtrees removed, and
all but a selected few mbg and rsg files removed.
williamr@2
     1
// Copyright (c) 1999-2009 Nokia Corporation and/or its subsidiary(-ies).
williamr@2
     2
// All rights reserved.
williamr@2
     3
// This component and the accompanying materials are made available
williamr@4
     4
// under the terms of "Eclipse Public License v1.0"
williamr@2
     5
// which accompanies this distribution, and is available
williamr@4
     6
// at the URL "http://www.eclipse.org/legal/epl-v10.html".
williamr@2
     7
//
williamr@2
     8
// Initial Contributors:
williamr@2
     9
// Nokia Corporation - initial contribution.
williamr@2
    10
//
williamr@2
    11
// Contributors:
williamr@2
    12
//
williamr@2
    13
// Description:
williamr@2
    14
// Declaration for Decompression class
williamr@2
    15
// 
williamr@2
    16
//
williamr@2
    17
williamr@2
    18
#ifndef __EZDECOMPRESSOR_H__
williamr@2
    19
#define __EZDECOMPRESSOR_H__
williamr@2
    20
williamr@2
    21
#include <e32base.h>
williamr@2
    22
#include <ezstream.h>
williamr@2
    23
#include <ezbufman.h>
williamr@2
    24
williamr@2
    25
/**
williamr@2
    26
The CEZDecompressor class provides in-memory de-compression functions, including integrity checks of the compressed data.
williamr@2
    27
This version of the library supports only one compression / de-compression method (deflation / inflation).  De-compression
williamr@2
    28
can be done in a single step (using DecompressL()) if the buffers are large enough (for example if an input file is mmap'ed),
williamr@2
    29
or can be done by repeated calls of the InflateL() function.  The source data is de-compressed to the target buffer (both source 
williamr@2
    30
and target contained within the buffer manager argument).
williamr@2
    31
williamr@4
    32
Note: In this version of the library a windowBits value of 8 is unsupported due to a problem with the window size being 
williamr@4
    33
set to 256 bytes. Although a value of 8 will be accepted by the CEZCompressor constructors, as it is being changed 
williamr@4
    34
internally by Zlib from 8 to 9, it will not be possible to use the same value for decompression. This is because the 
williamr@4
    35
Zlib functions called by the CEZDecompressor constructors do not make the same change internally and as a result a 
williamr@4
    36
KEZlibErrData is returned when calling InflateL(). It is therefore advised that for this version of the library 
williamr@4
    37
windowBits of 9 is used in place of 8.
williamr@4
    38
williamr@2
    39
@publishedAll
williamr@2
    40
@released
williamr@2
    41
*/
williamr@2
    42
class CEZDecompressor : public CEZZStream
williamr@2
    43
	{
williamr@2
    44
public:
williamr@2
    45
	/** Decompression panic values */
williamr@2
    46
	enum 
williamr@2
    47
		{
williamr@2
    48
		EInflateInitlialiserError = EUnexpected + 1,
williamr@2
    49
		EInflateVersionError,
williamr@2
    50
		EInflateTerminated,
williamr@2
    51
		EInflateDictionaryError
williamr@2
    52
		};
williamr@2
    53
		
williamr@2
    54
	/** Window Bits - the base two logarithm of the window size (the size of the history buffer) */
williamr@2
    55
	enum
williamr@2
    56
		{
williamr@2
    57
		EMaxWBits = MAX_WBITS
williamr@2
    58
		};
williamr@2
    59
williamr@2
    60
public:
williamr@2
    61
	~CEZDecompressor();
williamr@2
    62
williamr@2
    63
	IMPORT_C static CEZDecompressor* NewLC(MEZBufferManager& aInit, TInt aWindowBits = EMaxWBits);
williamr@2
    64
	IMPORT_C static CEZDecompressor* NewL(MEZBufferManager& aInit, TInt aWindowBits = EMaxWBits);
williamr@2
    65
williamr@2
    66
	IMPORT_C static CEZDecompressor* NewLC(MEZBufferManager& aInit, const TDesC8& aDictionary, TInt aWindowBits = EMaxWBits);
williamr@2
    67
	IMPORT_C static CEZDecompressor* NewL(MEZBufferManager& aInit, const TDesC8& aDictionary, TInt aWindowBits = EMaxWBits);
williamr@2
    68
williamr@2
    69
williamr@2
    70
	IMPORT_C void ResetL(MEZBufferManager& aInit);
williamr@2
    71
	IMPORT_C TBool InflateL();
williamr@2
    72
williamr@2
    73
	IMPORT_C static void DecompressL(TDes8 &aDestination, const TDesC8 &aSource);
williamr@4
    74
	
williamr@2
    75
	private:
williamr@2
    76
		enum TInflationState
williamr@2
    77
			{
williamr@2
    78
			ENoFlush,
williamr@2
    79
			EFinalize,
williamr@2
    80
			ETerminated
williamr@2
    81
			};
williamr@2
    82
williamr@2
    83
	private:
williamr@2
    84
		void SetDictionaryL();
williamr@2
    85
		CEZDecompressor(MEZBufferManager* aInit);
williamr@2
    86
		CEZDecompressor(MEZBufferManager* aInit, const TUint8 *aDictionary, TInt aLength);
williamr@2
    87
		void ConstructL(TInt aWindowBits);
williamr@2
    88
williamr@2
    89
	private:
williamr@2
    90
		MEZBufferManager* iBufferInit;
williamr@2
    91
		TInflationState iInflationState;
williamr@2
    92
		const TUint8* iDictionary;
williamr@2
    93
		TInt iDictionaryLength;
williamr@2
    94
	};
williamr@2
    95
williamr@2
    96
#endif
williamr@4
    97
williamr@4
    98