// 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\include\memmodel\epoc\mmubase\kblockmap.h

// Kernel-side functionality for processing block maps

// 

// WARNING: This file contains some APIs which are internal and are subject

//          to change without notice. Such APIs should therefore not be used

//          outside the Kernel and Hardware Services package.

//

#ifndef __KBLOCKMAP_H__

#define __KBLOCKMAP_H__

#include <e32ldr.h>

/**

The kernel-side representation of a block map.

*/

class TBlockMap

	{

public:

	TBlockMap();

	~TBlockMap();

	/**

	Initialise and populate kernel-side representation from a user-side block map

	@param aBlockMapInfo    	The user-side block map info structure.

	@param aBlockMapEntries 	Pointer to a buffer containg the user-side block map entries.

	                            This object takes ownership of the buffer.

	@param aBlockMapEntriesSize The size of the user-side block map entries in bytes.

	@param aReadUnitShift       Log2 of the paging device's read unit size.

	@param aDataLengthInFile 	The length of the (possibly compressed) code in the file.

	*/

	TInt Initialise(const SBlockMapInfoBase& aBlockMapInfo,

					TBlockMapEntryBase* aBlockMapEntries,

                    TInt aBlockMapEntriesSize,

					TInt aReadUnitShift,

					TInt aDataLengthInFile);

	/**

	A function supplied to Read that is called to read the actual data.

	@param aArg1   		An argument parameter passed to read.

	@param aArg2   		Another argument parameter passed to read.

	@param aBuffer 		The address of the buffer to read the data into.

	@param aBlockNumber The block number to read.

	@param aBlockCount 	The number of blocks to read.

	*/

	typedef TInt (*TReadFunc)(TAny* aArg1, TAny* aArg2, TLinAddr aBuffer, TInt aBlockNumber, TInt aBlockCount);

	/**

	Read data from the file described by the block map into a buffer.

	@param aBuffer   	  The buffer into which to read the data.

	@param aPos	   	 	  The offset from the start of the data at which to read.

	@param aLength   	  The length of data to read in bytes.

	@param aReadUnitShift Log2 of the paging device's read unit size.

	@param aReadFunc 	  The function to call to read the blocks of data.

	@param aArg1   		  An argument parameter passed to read.

	@param aArg2   		  Another argument parameter passed to read.

	@return The offset into the buffer at which the data starts, or one of the system-wide error

	codes.

	*/

	TInt Read(TLinAddr aBuffer, TInt aPos, TInt aLength, TInt aReadUnitShift, TReadFunc aReadFunc, TAny* aArg1, TAny* aArg2) const;

	/**

	A contiguous area of media containing (possibly compressed) code.

	*/

	struct SExtent

		{

		TInt iDataOffset;		// position in file from, counting from start of code data

		TUint iBlockNumber;		// block number containg this position

		};

	inline TInt Count() const;

	inline const SExtent& Extent(TInt aIndex) const;

	inline TInt DataLength() const;

	/**

	Print out the contents of this object for debugging purposes.

	This method is only implemented in debug builds.

	*/

	void Dump() const;

private:

	TInt FindFirstExtent(TInt aPos) const;

private:

	TInt iDataLength;

	TInt iExtentCount;

	SExtent* iExtents;

	};

inline TInt TBlockMap::Count() const

	{

	return iExtentCount;

	}

inline const TBlockMap::SExtent& TBlockMap::Extent(TInt aIndex) const

	{

	return iExtents[aIndex];

	}

inline TInt TBlockMap::DataLength() const

	{

	return iDataLength;

	}

#endif