e32tools/e32lib/e32image/deflate/deflate.h
author Richard Taylor <richard.i.taylor@nokia.com>
Thu, 29 Apr 2010 09:54:32 +0100
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// Copyright (c) 1998-2009 Nokia Corporation and/or its subsidiary(-ies).
// All rights reserved.
// This component and the accompanying materials are made available
// under the terms of "Eclipse Public License v1.0"
// which accompanies this distribution, and is available
// at the URL "http://www.eclipse.org/legal/epl-v10.html".
//
// Initial Contributors:
// Nokia Corporation - initial contribution.
//
// Contributors:
//
// Description:
// e32tools\petran\Szip\deflate.h
// 
//

#ifndef __DECODE_H__
#define __DECODE_H__

#include "huffman.h"
#include <e32base.h>

// deflation constants
const TInt KDeflateLengthMag=8;
const TInt KDeflateDistanceMag=12;
//
const TInt KDeflateMinLength=3;
const TInt KDeflateMaxLength=KDeflateMinLength-1 + (1<<KDeflateLengthMag);
const TInt KDeflateMaxDistance=(1<<KDeflateDistanceMag);
const TInt KDeflateDistCodeBase=0x200;
// hashing
const TUint KDeflateHashMultiplier=0xAC4B9B19u;
const TInt KDeflateHashShift=24;

class TEncoding
	{
public:
	enum {ELiterals=256,ELengths=(KDeflateLengthMag-1)*4,ESpecials=1,EDistances=(KDeflateDistanceMag-1)*4};
	enum {ELitLens=ELiterals+ELengths+ESpecials};
	enum {EEos=ELiterals+ELengths};
public:
	TUint32 iLitLen[ELitLens];
	TUint32 iDistance[EDistances];
	};

const TInt KDeflationCodes=TEncoding::ELitLens+TEncoding::EDistances;

class CInflater
	{
public:
	enum {EBufSize = 0x800, ESafetyZone=8};
public:
	static CInflater* NewLC(TBitInput& aInput);
	~CInflater();
//
	TInt ReadL(TUint8* aBuffer,TInt aLength);
	TInt SkipL(TInt aLength);
private:
	CInflater(TBitInput& aInput);
	void ConstructL();
	void InitL();
	TInt InflateL();
private:
	TBitInput* iBits;
	const TUint8* iRptr;			// partial segment
	TInt iLen;
	const TUint8* iAvail;			// available data
	const TUint8* iLimit;
	TEncoding* iEncoding;
	TUint8* iOut;					// circular buffer for distance matches
	TUint8 iHuff[EBufSize+ESafetyZone];			// huffman data
	};

void DeflateL(const TUint8* aBuf, TInt aLength, TBitOutput& aOutput);

#endif