sl@0: // Copyright (c) 2006-2009 Nokia Corporation and/or its subsidiary(-ies).
sl@0: // All rights reserved.
sl@0: // This component and the accompanying materials are made available
sl@0: // under the terms of "Eclipse Public License v1.0"
sl@0: // which accompanies this distribution, and is available
sl@0: // at the URL "http://www.eclipse.org/legal/epl-v10.html".
sl@0: //
sl@0: // Initial Contributors:
sl@0: // Nokia Corporation - initial contribution.
sl@0: //
sl@0: // Contributors:
sl@0: //
sl@0: // Description:
sl@0: //
sl@0: 
sl@0: #ifndef READERS_H
sl@0: #define READERS_H
sl@0: 
sl@0: #include "constants.h"
sl@0: #include "mmruf.h"
sl@0: 
sl@0: 
sl@0: static const TInt KAACFrameHeaderSize = 7;
sl@0: static const TInt KMP3FrameHeaderSize = 4;
sl@0: static const TInt KBufSize = 64;
sl@0: 
sl@0: 
sl@0: //
sl@0: // This class provides a level of abstraction that allows
sl@0: // for parsing data. It is necessary because AppArc may
sl@0: // only provide a buffer that contains a limited snapshot
sl@0: // of the beginning of a file, or a file handle that allows
sl@0: // the whole file to be parsed.
sl@0: //
sl@0: class CReader : public CBase
sl@0: 	{
sl@0: public:
sl@0: 
sl@0: 	//
sl@0: 	// Enums used so that CParsers can determine
sl@0: 	// the type of reader they've been given.
sl@0: 	//
sl@0: 	typedef enum
sl@0: 		{
sl@0: 		EUnknown = 0,
sl@0: 		EBuffer = 1,
sl@0: 		EFile = 2
sl@0: 		}
sl@0: 	TReaderType;
sl@0: 	
sl@0: 	//
sl@0: 	// This function resets the reader such that the next
sl@0: 	// read operation will be performed from the start of
sl@0: 	// the source.
sl@0: 	// For a CFileReader the buffer is filled from the start
sl@0: 	// of the file, for a CBufferReader the position in the 
sl@0: 	// buffer is set to zero.
sl@0: 	//
sl@0: 	virtual void Reset() { iBufPos = 0; }
sl@0: 	
sl@0: 	//
sl@0: 	// Seeks within the source.
sl@0: 	// This function tries to support 64-bit compatible file
sl@0: 	// formats as much as possible, but there may be some
sl@0: 	// instances when the operation cannot be performed due to
sl@0: 	// limitations of the file server.
sl@0: 	//
sl@0: 	virtual void SeekL(TInt64 aOffset) = 0;
sl@0: 	
sl@0: 	//
sl@0: 	// Seeks within the source.
sl@0: 	//
sl@0: 	virtual void SeekL(TInt aOffset) = 0;
sl@0: 	
sl@0: 	//
sl@0: 	// Returns the current position in the buffer.
sl@0: 	//
sl@0: 	virtual TInt Position() { return iBufPos; }
sl@0: 		
sl@0: 	//
sl@0: 	// Data reading routines.
sl@0: 	//
sl@0: 	TBool Match(const TDesC8& aPattern);
sl@0: 	void Read64L(TInt64& aData, TBool aLittleEndian = EFalse);
sl@0: 	void Read32L(TUint32& aData, TBool aLittleEndian = EFalse);
sl@0: 	void Read16L(TUint16& aData, TBool aLittleEndian = EFalse);
sl@0: 	void ReadByteL(TUint8& aData);
sl@0: 	void ReadBytesL(TDes8& aData);
sl@0: 
sl@0: 	//
sl@0: 	// Gets the type of Reader being used.
sl@0: 	//
sl@0: 	inline TReaderType Type() { return iType; }
sl@0: 		
sl@0: protected:
sl@0: 	CReader(const TDesC8& aBuffer, CReader::TReaderType aType);
sl@0: 	
sl@0: 	//
sl@0: 	// Returns ETrue if there is aAmount of unread bytes available,
sl@0: 	// EFalse otherwise.
sl@0: 	//
sl@0: 	virtual TBool CheckEnoughData(TInt aAmount);
sl@0: 	
sl@0: 	//
sl@0: 	// Non-leaving Seek
sl@0: 	//
sl@0: 	TInt Seek(TInt aOffset);
sl@0: 	TInt Seek(TInt64 aOffset);
sl@0: 	
sl@0: private:
sl@0: 	const TDesC8& iBuffer;		// The buffer that contains the source data.
sl@0: 	TInt iBufPos;				// The current position in the data source.
sl@0: 	CReader::TReaderType iType;	// The type of reader it is.
sl@0: 	};
sl@0: 
sl@0: 
sl@0: //
sl@0: // This class allows reading and seeking operations to be
sl@0: // performed on a data buffer. This is used when no file
sl@0: // handle is available to the recogniser.
sl@0: //
sl@0: class CBufferReader : public CReader
sl@0: 	{
sl@0: public:
sl@0: 	static CBufferReader* NewLC(const TDesC8& aBuffer);
sl@0: 	virtual ~CBufferReader();
sl@0: 	void Reset();
sl@0: 	void SeekL(TInt aOffset);				// CReader
sl@0: 	void SeekL(TInt64 aOffset);				// CReader
sl@0: 
sl@0: protected:
sl@0: 	CBufferReader(const TDesC8& aBuffer);
sl@0: 	CBufferReader(const TDesC8& aBuffer, TReaderType aType);
sl@0: 	void ConstructL();
sl@0: 	};
sl@0: 
sl@0: 
sl@0: //
sl@0: // This class allows reading and seeking operations to be
sl@0: // performed on a file handle. This is used when a file
sl@0: // handle is available to the recogniser.
sl@0: //
sl@0: class CFileReader : public CBufferReader
sl@0: 	{
sl@0: public:
sl@0: 	static CFileReader* NewLC(RFile* aFile);
sl@0: 	virtual ~CFileReader();
sl@0: 	void Reset();
sl@0: 	
sl@0: 	//
sl@0: 	// CReader::Position() override.
sl@0: 	//
sl@0: 	TInt Position() { return CBufferReader::Position() + iFilePos; }
sl@0: 		
sl@0: 	void SeekL(TInt aOffset);			// CReader
sl@0: 	void SeekL(TInt64 aOffset);			// CReader
sl@0: 	
sl@0: protected:
sl@0: 	CFileReader(RFile* aFile);
sl@0: 	void ConstructL();
sl@0: 	TBool CheckEnoughData(TInt aAmount);	// CReader
sl@0: 	
sl@0: 	//
sl@0: 	// Seeks to a new file location and fills the buffer from there.
sl@0: 	//
sl@0: 	TInt PhysicallySeekAndRead(TInt aAmount);
sl@0: 	TInt PhysicallySeekAndRead(TInt64 aOffset);
sl@0: private:
sl@0: 	RFile* iFile;
sl@0: 	TInt64 iFilePos;
sl@0: 	TBuf8<KBufSize> iFileBuffer;
sl@0: 	};
sl@0: 	
sl@0: 	
sl@0: #endif
sl@0: