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: #include "readers.h"
sl@0: 
sl@0: //
sl@0: //
sl@0: //
sl@0: CFileReader::CFileReader(RFile* aFile)
sl@0:  :	CBufferReader(iFileBuffer, CReader::EFile),
sl@0:  	iFile(aFile)
sl@0: 	{
sl@0: 	}
sl@0: 
sl@0: 
sl@0: //
sl@0: //
sl@0: //
sl@0: CFileReader::~CFileReader()
sl@0: 	{
sl@0: 	}
sl@0: 
sl@0: 
sl@0: //
sl@0: //
sl@0: //
sl@0: CFileReader* CFileReader::NewLC(RFile* aFile)
sl@0: 	{
sl@0: 	CFileReader* self = new(ELeave) CFileReader(aFile);
sl@0: 	CleanupStack::PushL(self);
sl@0: 	self->ConstructL();
sl@0: 	return self;
sl@0: 	}
sl@0: 
sl@0: 
sl@0: //
sl@0: //
sl@0: //
sl@0: void CFileReader::ConstructL()
sl@0: 	{
sl@0: 	TInt pos = 0;
sl@0: 	User::LeaveIfError(iFile->Seek(ESeekStart, pos));
sl@0: 	User::LeaveIfError(iFile->Read(iFileBuffer));
sl@0: 	}
sl@0: 
sl@0: 
sl@0: //
sl@0: // Checks if there is aAmount of data left in the buffer.
sl@0: // It is important to call the base-class implementation first
sl@0: // to ensure correct operation.
sl@0: //
sl@0: TBool CFileReader::CheckEnoughData(TInt aAmount)
sl@0: 	{
sl@0: 	if (CBufferReader::CheckEnoughData(aAmount))
sl@0: 		{
sl@0: 		return ETrue;
sl@0: 		}
sl@0: 		
sl@0: 	// Try to read more data.
sl@0: 	TInt bufPos = CBufferReader::Position();
sl@0: 	TInt err = PhysicallySeekAndRead(bufPos - iFileBuffer.Length());
sl@0: 	if (err == KErrNone)
sl@0: 		{
sl@0: 		// The read may have succeeded but that 
sl@0: 		// still doesn't mean we have enough data.
sl@0: 		return (aAmount <= iFileBuffer.Length());
sl@0: 		}
sl@0: 	
sl@0: 	return EFalse;
sl@0: 	}
sl@0: 
sl@0: 
sl@0: //
sl@0: //
sl@0: //
sl@0: void CFileReader::Reset()
sl@0: 	{
sl@0: 	CBufferReader::Reset(); // This will reset iBufPos.
sl@0: 	
sl@0: 	if (iFilePos != 0)
sl@0: 		{
sl@0: 		// We need to seek to the start and fill the buffer.
sl@0: 		iFilePos = 0;
sl@0: 		TInt filepos = 0;
sl@0: 		TInt err = iFile->Seek(ESeekStart, filepos);
sl@0: 		if (err == KErrNone)
sl@0: 			{
sl@0: 			err = iFile->Read(iFileBuffer);
sl@0: 			}
sl@0: 			
sl@0: 		if (err != KErrNone)
sl@0: 			{
sl@0: 			iFileBuffer.Zero();
sl@0: 			}
sl@0: 		}
sl@0: 	else
sl@0: 		{
sl@0: 		// There's no need to seek and read.
sl@0: 		iFilePos = 0;
sl@0: 		}
sl@0: 	}
sl@0: 
sl@0: 
sl@0: //
sl@0: //
sl@0: //
sl@0: void CFileReader::SeekL(TInt aOffset)
sl@0: 	{
sl@0: 	TInt err = CReader::Seek(aOffset);
sl@0: 	if (err == KErrUnderflow)
sl@0: 		{
sl@0: 		TInt bufPos = CBufferReader::Position();
sl@0: 		aOffset += bufPos - iFileBuffer.Length();
sl@0: 		User::LeaveIfError(PhysicallySeekAndRead(aOffset));
sl@0: 		}
sl@0: 	}
sl@0: 
sl@0: 
sl@0: //
sl@0: // It could be possible for a 64-bit field in formats such as MPEG4
sl@0: // to have values that would fit in a 32-bit variable. In this case
sl@0: // we can use it for seeking. This function checks if a 64-bit value
sl@0: // is compatible with RFile's 32-bit operations.
sl@0: //
sl@0: void CFileReader::SeekL(TInt64 aOffset)
sl@0: 	{
sl@0: 	if (aOffset < KMinTInt64)
sl@0: 		{
sl@0: 		User::Leave(KErrNotSupported);
sl@0: 		}
sl@0: 		
sl@0: 	if (aOffset > KMaxTInt64)
sl@0: 		{
sl@0: 		User::Leave(KErrNotSupported);
sl@0: 		}
sl@0: 	
sl@0: 	if (aOffset < (TInt64)KMaxTInt)
sl@0: 	    {
sl@0:         TInt low = (TInt)I64LOW(aOffset);
sl@0:         SeekL(low);
sl@0: 	    }
sl@0: 	else
sl@0: 	    {
sl@0:         TInt err = CReader::Seek(aOffset);
sl@0:         if (err == KErrUnderflow)
sl@0:             {
sl@0:             TInt64 bufPos = CBufferReader::Position();
sl@0:             aOffset += bufPos - iFileBuffer.Length();
sl@0:             User::LeaveIfError(PhysicallySeekAndRead(aOffset));
sl@0:             }
sl@0: 	    }
sl@0: 	}
sl@0: 	
sl@0: //
sl@0: // This function seeks forward/backward aOffset bytes
sl@0: // and fills the buffer from that point.
sl@0: //
sl@0: TInt CFileReader::PhysicallySeekAndRead(TInt aOffset)
sl@0: 	{
sl@0: 	TInt err;
sl@0: 	
sl@0: 	// New buffer contents so read from the start of it.
sl@0: 	CBufferReader::Reset();
sl@0: 	
sl@0: 	iFilePos = aOffset;
sl@0: 	err = iFile->Seek(ESeekCurrent, aOffset);
sl@0: 	
sl@0: 	if (err != KErrNone)
sl@0: 		{
sl@0: 		return err;
sl@0: 		}
sl@0: 
sl@0: 	err = iFile->Read(iFileBuffer);
sl@0: 	if (err != KErrNone)
sl@0: 		{
sl@0: 		return err;
sl@0: 		}
sl@0: 	return (iFileBuffer.Length() == 0 ? KErrEof : KErrNone);
sl@0: 	}
sl@0: TInt CFileReader::PhysicallySeekAndRead(TInt64 aOffset)
sl@0:     {
sl@0:     TInt err;
sl@0:     // New buffer contents so read from the start of it.
sl@0:     CBufferReader::Reset();
sl@0:     
sl@0:     iFilePos = aOffset;
sl@0:     RFile64* tempfile;
sl@0:     tempfile = static_cast<RFile64*> (iFile);
sl@0:  
sl@0:     err = tempfile->Seek(ESeekCurrent, iFilePos);
sl@0: 	if (err != KErrNone)
sl@0: 		{
sl@0: 		return err;
sl@0: 		}
sl@0: 
sl@0: 	err = iFile->Read(iFileBuffer);
sl@0: 	if (err != KErrNone)
sl@0: 		{
sl@0: 		return err;
sl@0: 		}
sl@0: 		
sl@0: 	return (iFileBuffer.Length() == 0 ? KErrEof : KErrNone);
sl@0: 	}
sl@0: