// 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 "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:

//

#include <assert.h>

#include <pcstore/storeexception.h>

#include "filestreambuf.h"

namespace PCStore

{

/**

Constructs a file stream buffer object with the specified file name and open mode.

Opens the file in specified read/write mode.

@param aFileName The name of the file which the file stream buffer will open and access.

@param aMode The mode in which the file would be opened.

@exception TStoreException::EFileOpenError Error occurs in file opening.

*/

CFileStreamBuf::CFileStreamBuf(const char* aFileName, TFileMode aMode)

	:iFile(NULL), iStreamOpened(false)

	{

	if(aMode == EWriteFile) 

		{

		iFile=fopen(aFileName,"wb");

		}

	else

		{

		iFile=fopen(aFileName,"rb");

		}

	if(iFile == NULL) 

		{

		throw TStoreException(TStoreException::EFileOpenError);

		}

	}

/**

Destructor.

Closes the file.

*/

CFileStreamBuf::~CFileStreamBuf()

	{

	fclose(iFile);

	}

/**

Flags that a stream with the specified stream id is opened.

Checks whether a stream has been opened. If not, moves the file pointer to the position 

which is represented by the given stream id, and sets the stream open flag to TRUE. If a 

stream has been opened, throws an exception.

This function is called by the constructor of CStoreReadStream and CStoreWriteStream

to flag the new stream is opened. 

@param aStreamId The stream id of the open stream.

@exception TStoreException::EStreamExclusionError Another stream is still opened.

@exception TStoreException::EFileSeekError Error occurs when seeking within the file 

due to an incorrect stream id or other reason.

*/

void CFileStreamBuf::StreamOpen(TStreamId aStreamId)

	{

	//check the opened stream

	if(iStreamOpened)

		{

		throw TStoreException(TStoreException::EStreamExclusionError);

		}

	// set pointer to the correct position

	TInt ret = fseek(iFile,aStreamId.Value(),SEEK_SET);  

	if(ret)

		{

		throw TStoreException(TStoreException::EFileSeekError);

		}

	iStreamOpened = true;

	}

/** 

Flags that the opened stream is closed.

This function is called by the destructor of the CStoreReadStream and CStoreWriteStream 

to indicate the stream is being closed.

*/

void CFileStreamBuf::StreamClose()

	{

	iStreamOpened = false;

	}

/**

Gets a new stream id which will be used to create a write stream.

The new stream id is the end position of the store file.

Moves the read/write pointer to the end to the file to get the stream id.

@return The new stream id.

@exception TStoreException::EStreamExclusionError Another stream is still opened.

@exception TStoreException::EFileSeekError Error occurs when the file pointer is moved to 

the end of file.

*/	

TStreamId CFileStreamBuf::GetNewStreamId()

	{

	//check the opened stream

	if(iStreamOpened)

		{

		throw TStoreException(TStoreException::EStreamExclusionError);

		}

	// move pointer to the end of the file

	TInt ret = fseek(iFile,0,SEEK_END);  

	if(ret) 

		{

		throw TStoreException(TStoreException::EFileSeekError);

		}

	TUint size = ftell(iFile);

	TStreamId id = size;

	return id;

	}

/**

Reads the specified length of 8-bit data to the supplied buffer from the file.

Assert aLength must not be negative and aPtr must not be NULL.

@param aPtr The pointer to the buffer to receive the read data.

@param aLength The length of the data to read.

@exception TStoreException::EFileReadError Error occurs in data reading.

*/

void CFileStreamBuf::Read(const TUint8* aPtr, TInt32 aLength)

	{

	assert(aLength >= 0 && aPtr != NULL);

	if (aLength > 0) 

		{

		size_t numRead;

		numRead = fread(reinterpret_cast<void*>(const_cast<TUint8*>(aPtr)),\

			sizeof(TUint8), aLength, iFile);

		if(numRead < static_cast<TUint32>(aLength))

			{

			throw TStoreException(TStoreException::EFileReadError);

			}

		}

	}

/**

Writes the specified length of 8-bit data from the supplied buffer to the file.

Assert aLength must not be negative and aPtr must not be NULL.

@param aPtr The pointer to the buffer holding the written data.

@param aLength The length of the data to write.

@exception TStoreException::EFileWriteError Error occurs in data writing.

*/

void CFileStreamBuf::Write(const TUint8* aPtr, TInt32 aLength)

	{

	assert(aLength >= 0 && aPtr != NULL);	

	if (aLength > 0)

		{

		size_t numWritten ;

		numWritten  = fwrite(reinterpret_cast<void*>(const_cast<TUint8*>(aPtr)),\

			sizeof(TUint8), aLength, iFile);

		if(numWritten < static_cast<TUint32>(aLength))

			{

			throw TStoreException(TStoreException::EFileWriteError);

			}

		}

	}

}