os/graphics/fbs/fontandbitmapserver/inc/FBSMBMC.H
author sl@SLION-WIN7.fritz.box
Fri, 15 Jun 2012 03:10:57 +0200
changeset 0 bde4ae8d615e
permissions -rw-r--r--
First public contribution.
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// Copyright (c) 2004-2009 Nokia Corporation and/or its subsidiary(-ies).
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// All rights reserved.
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// This component and the accompanying materials are made available
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// under the terms of "Eclipse Public License v1.0"
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// which accompanies this distribution, and is available
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// at the URL "http://www.eclipse.org/legal/epl-v10.html".
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//
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// Initial Contributors:
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// Nokia Corporation - initial contribution.
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//
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// Contributors:
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//
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// Description:
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// This file holds the class declarations for the CFbTopMBMCache 
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// The cache is used to store the stream ids of bitmaps in a MBM file
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// 
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//
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#ifndef __FBSMBMC_H__
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#define __FBSMBMC_H__
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#include <e32std.h>
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#include <e32base.h>
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#include <s32std.h>
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#include "ShiftedFileStore.h"
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//This class holds the TStreamIds of the bitmaps stored in an MBM file
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//and the filestore of the last loaded bitmap file. The idea of the cache
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//is to speed up loading of bitmaps from a mbm file by skipping the file
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//opening process and mapping the MBM id directly to the Stream ids stored
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//in the cache
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//
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NONSHARABLE_CLASS(CFbTopStreamIdCache): public CBase
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	{
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public:
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	CFbTopStreamIdCache(TInt aForwardSize, TInt aBackwardSize, TInt aMaxFilestores);
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	~CFbTopStreamIdCache();
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	TStreamId GetStreamIdL(RFile& aFile,const TDesC& aFilename,TInt32 aId,TUint aFileOffset, TInt aSessionHandle);
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	TStreamId GetStreamIdL(RFs& aFs,const TDesC& aFilename,TInt32 aId,TUint aFileOffset, TInt aSessionHandle);
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	CShiftedFileStore* MruFileStore();
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	void FlushCache();
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	void CloseFileStores(TInt aSessionHandle=0);	// If aSessionHandle is not passed, all file stores will be closed
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private:
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	class RCacheEntry;
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	RCacheEntry* AddCacheEntryL(const TDesC& aFilename, TUint aFileOffset);
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	RCacheEntry* FindCacheEntry(const TDesC& aFilename, TUint aFileOffset);
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private:
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	RPointerArray<RCacheEntry> iEntries;	// Array of pointers to the cache entries in least-recently-used order
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	TUint8* iBuffer;						// Buffer for storage of the cache entries
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	const TInt iForwardCacheSize;			// Max number of cached bitmap ids after the last requested bitmap id
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	const TInt iBackwardCacheSize;			// Max number of cached bitmap ids before the last requested bitmap id
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	const TInt iMaxCacheFilestores;			// Max number of filestores in the cache
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	friend class CTStreamIdCache;			// This is used for testing purposes
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	};
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class CFbTopStreamIdCache::RCacheEntry
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	{
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public:
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	RCacheEntry(const TDesC& aFilename, TUint aFileOffset);
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	TBool SameFile(const TDesC& aFilename, TUint aFileOffset);
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	TStreamId GetStreamIdL(TInt32 aId, TInt aForwardSize, TInt aBackwardSize);
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	CShiftedFileStore* FileStore();
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	void CloseFileStore();
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	TInt SessionHandle() const;
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	void CreateFileStoreL(RFile& aFile, TInt aSessionHandle);
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	void CreateFileStoreL(RFs& aFs, const TDesC& aFilename, TInt aSessionHandle);
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public:
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	static const TInt KBaseSize;		// Size of the class excluding array iStreamIdCache
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private:
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	TBufC<KMaxFileName>	iFilename;		// Name of the mbm file
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	TUint iFileOffset;					// Offset into the mbm file
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	CShiftedFileStore *iFilestore;		// File store for the mbm file
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	TInt iLastId;						// Last requested bitmap id from the mbm file
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	TInt iStreamIdCount;				// Number of stream ids from the mbm file
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	TInt iSessionHandle;				// Handle to the associated client session
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	// Keep always iStreamIdCache as the last data member
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	// Memory for it is allocated in CFbTopStreamIdCache::AddCacheEntryL()
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	TStreamId iStreamIdCache[1];		// Array of stream ids from the mbm file
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	friend class CTStreamIdCache;		// This is used for testing purposes
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	};
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#endif