/*

* Copyright (c) 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:

*

*/

#ifndef __HUFFMAN_H__

#define __HUFFMAN_H__

#include "e32defwrap.h"

#include <fstream>

/**

Base class for E32Image Compression Errors.

@internalComponent

@released

*/

class E32ImageCompressionError

{

    public:

        enum

            {

		    HUFFMANBUFFEROVERFLOWERROR = -1,

            HUFFMANBUFFERUNDERFLOWERROR = -2,

		    HUFFMANTOOMANYCODESERROR = -3,

		    HUFFMANINVALIDCODINGERROR = -4,

            };

	public:

		E32ImageCompressionError(int aError)

            {

            iError = aError;

            }

    public:

        int iError;

};

/**

Class for Bit input stream.

Good for reading bit streams for packed, compressed or huffman data algorithms.

@since 8.0

@library euser.lib

@internalComponent

@released

*/

class TBitInput

{

	public:

		TBitInput();

		TBitInput(const TUint8* aPtr, TInt aLength, TInt aOffset=0);

		void Set(const TUint8* aPtr, TInt aLength, TInt aOffset=0);

		TUint ReadL();

		TUint ReadL(TInt aSize);

		TUint HuffmanL(const TUint32* aTree);

	private:

		virtual void UnderflowL();

	private:

		TInt iCount;

		TUint iBits;

		TInt iRemain;

		const TUint32* iPtr;

};

/**

Class derived from TBitInput

@internalComponent

@released

*/

class TFileInput : public TBitInput

{

	public:

		TFileInput(unsigned char* source,int size);

		~TFileInput();

	private:

		void UnderflowL();

	private:

		TUint8* iReadBuf;

		TInt iSize;

};

/*

Class for Huffman code toolkit.

This class builds a huffman encoding from a frequency table and builds a decoding tree from a

code-lengths table.

The encoding generated is based on the rule that given two symbols s1 and s2, with code

length l1 and l2, and huffman codes h1 and h2:

	if l1<l2 then h1<h2 when compared lexicographically

	if l1==l2 and s1<s2 then h1<h2 ditto

This allows the encoding to be stored compactly as a table of code lengths

@since 8.0

@library euser.lib

@internalComponent

@released

*/

class Huffman

{

	public:

		enum {KMaxCodeLength=27};

		enum {KMetaCodes=KMaxCodeLength+1};

		enum {KMaxCodes=0x8000};

	public:

		static void HuffmanL(const TUint32 aFrequency[],TInt aNumCodes,TUint32 aHuffman[]);

		static void Encoding(const TUint32 aHuffman[],TInt aNumCodes,TUint32 aEncodeTable[]);

		static TBool IsValid(const TUint32 aHuffman[],TInt aNumCodes);

		static void Decoding(const TUint32 aHuffman[],TInt aNumCodes,TUint32 aDecodeTree[],TInt aSymbolBase=0);

		static void InternalizeL(TBitInput& aInput,TUint32 aHuffman[],TInt aNumCodes);

};

// local definitions used for Huffman code generation

typedef TUint16 THuff;		/** @internal */

const THuff KLeaf=0x8000;	/** @internal */

struct TNode

/** @internal */

{

	TUint iCount;

	THuff iLeft;

	THuff iRight;

};

const TInt KDeflateLengthMag=8;

const TInt KDeflateDistanceMag=12;

/**

class for TEncoding

@internalComponent

@released

*/

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;

#endif