// Copyright (c) 2006-2009 Nokia Corporation and/or its subsidiary(-ies).

// All rights reserved.

// This component and the accompanying materials are made available

// under the terms of the License "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:

// e32\kernel\crashgzip.h

// Definitions for using Zlib 

// 

//

#ifndef _CRASHGZIP_H

#define _CRASHGZIP_H

#include "crashwriter.h"

#include "zutil.h"

#include "zlib.h"

#include "deflate.h"

//********** NOTE ************************************************************

//	This header MUST updated if the version of Zlib used by the crash 

//	logger is changed from 1.2.3.

//****************************************************************************

/** Sets the size of the history window to be used by delfate()

	@internalComponent

*/	

const TInt KCrashZlibWinBits = 12; 	// 4KB window

/**	Sets level of RAM use if deflate, higher value can

	mean more compression

	@internalComponent

*/		

const TInt KCrashZlibMemLvl = 4;	// 8KB for deflate to play with

/*****************************************************************************

	Constants for calculating the size of 'heap' buffers used by deflate.

*****************************************************************************/

/** Constant for w_size  extracted from deflateInit2_ (v1.2.3):

    s->w_bits = windowBits;

    s->w_size = 1 << s->w_bits;

    @internalComponent

*/

const TInt KCrashZlib_w_size = 1 << KCrashZlibWinBits;

/** Constant for hash_size extracted from deflateInit2_:

    s->hash_bits = memLevel + 7;

    s->hash_size = 1 << s->hash_bits;

    @internalComponent

*/

const TInt KCrashZlib_hash_size = 1 << (KCrashZlibMemLvl+7);

/** Constant for lit_bufsize extract from deflateInit2_:

    s->lit_bufsize = 1 << (memLevel + 6);

    @internalComponent

*/

const TInt KCrashZlib_lit_bufsize = 1 << (KCrashZlibMemLvl + 6);

/*****************************************************************************

	Constants for the size of the buffers allocated on the 'heap' for the

	deflate algorithm in deflateInit2_()

*****************************************************************************/

/**	Size of buffer used to keep state of deflate algorthim, deflate_state.

	@internalComponent

*/

const TInt KCrashZlibBuf1Size = KCrashZlib_w_size * 2 * sizeof(Byte);

/** Size of buffer used for history window

	@internalComponent

*/

const TInt KCrashZlibBuf2Size = KCrashZlib_w_size * sizeof(ush);

/**	Size of buffer s->prev

	@internalComponent

*/

const TInt KCrashZlibBuf3Size = KCrashZlib_hash_size * sizeof(ush);

/**	Size of buffer s->head

	s->lit_bufsize(*sizeof(ush)+2)

	@internalComponent

*/

const TInt KCrashZlibBuf4Size = KCrashZlib_lit_bufsize * (sizeof(ush)+2);

/******************************************************************************

	Definitions for creating GZip compatible output using zlib

******************************************************************************/

/** The number of bytes the GZip footer will require.

	Extracted from rfc1952.txt - GZIP file format specification version 4.3

	[page 5]

	@internalComponent

*/	

const TInt KCrashGzipFooterSize = 8;

/** Amount of bytes required to ensure the gzip file can be closed 

 	successfully

 	@internalComponent

 */

const TInt KCrashGzipFooterMax = KCrashZlibBuf4Size+KCrashGzipFooterSize;

/** Number of bytes of input data to buffer up before passing to deflate

	@internalComponent

*/

const TInt KCrashGzipInBufSize = 128;

/**	Size of the buffer for the deflate to pass it output data to.

	As deflate is creating the GZIP header & footer info this must be large 

	enough for the gzip header on the first call of 

	@internalComponent

*/							

const TInt KCrashGzipOutBufSize = 128;

/** Number of seconds elapsed between 01/01/0000 AD and 01/01/1970 AD.

    Value is the number of days multiplied by the number of seconds per day:

    719540 * 86400

 */

const TInt64 KYear1970ADInSeconds = I64LIT(62168256000);

/** Wrapper class for Zlib deflate

	@internalComponent

*/							

class MCrashGzip : public MCrashWriter

	{

public:

	/** Initialise ready for data output.  Sets the deflate algorithm up.

		@param aFlash The object to write to the crash logger flash sector

	*/

	TBool Init();

	/** Write the passed data via the deflate compressor

		@param aDes The data to be written

		@return TInt Returns ETrue if the log output has been truncated

	*/

	TBool Write(const TDesC8& aDes);

	/** Ensure all compressed data is written to the crash logger flash 

		and force deflate to output the GZip footer data.

	*/

	void FlushEnd();

	/** Return the number of uncompressed bytes contained in the 

		compressed data.

		@return Number of bytes in the compressed data

	*/

	TUint32 GetDataCompressed();	

private:

	TBuf8<KCrashGzipInBufSize> iInBuf; /** Buffer for deflate input*/

	TBuf8<KCrashGzipOutBufSize> iOutBuf;/** Buffer for data for crash log sector*/

	TInt iOutBufLen;				/** No of bytes currently in iOutBuf*/

	z_stream iDeflateStrm;			/** Stream to be used by deflate*/

private:

	/** The max no. of bytes that can be written */

	TInt iMaxBytes;

	/** The number of bytes output so far*/

	TInt iBytesOut;

	};

#endif //_CRASHGZIP_H