imgtools/imglib/filesystem/source/fat16filesystem.cpp
changeset 590 360bd6b35136
parent 0 044383f39525
--- a/imgtools/imglib/filesystem/source/fat16filesystem.cpp	Wed Jun 16 16:51:40 2010 +0300
+++ b/imgtools/imglib/filesystem/source/fat16filesystem.cpp	Wed Jun 23 16:56:47 2010 +0800
@@ -1,318 +1,318 @@
-/*
-* 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: 
-* CFat16FileSystem is the concrete class which is responsible for 
-* creating a FAT16 image. This class constitutes the method to 
-* create boot sector, FAT Table and data region of a FAT16 Image
-* @internalComponent
-* @released
-*
-*/
-
-#include"fat16filesystem.h"
-
-
-/**
-Initializes the boot sector of a FAT 16 volume
-
-@internalComponent
-@released
-
-@param aPartitionSize partition size in bytes
-@param aConfigurableFatAttributes ConfigurableFatAttributes
-*/
-void CFat16FileSystem::CreateBootSector(Long64 aPartitionSize,ConfigurableFatAttributes* aConfigurableFatAttributes)
-{
- 	iFAT16BootSector.SetOEMName();
-	unsigned char* OEMName = iFAT16BootSector.OEMName();
-	iFAT16BootSector.SetJumpInstruction();
-	unsigned char* JmpBoot = iFAT16BootSector.JumpInstruction();
-	iFAT16BootSector.SetBytesPerSector(aConfigurableFatAttributes->iDriveSectorSize);
-	unsigned short BytesPerSector = (unsigned short)iFAT16BootSector.BytesPerSector();
-	iFAT16BootSector.ComputeSectorsPerCluster(aPartitionSize);
-	unsigned char SectorsPerCluster = iFAT16BootSector.SectorsPerCluster();
-	iFAT16BootSector.SetReservedSectors();
-	unsigned short ReservedSectors = iFAT16BootSector.ReservedSectors();
-	iFAT16BootSector.SetNumberOfFats(aConfigurableFatAttributes->iDriveNoOfFATs);
-	unsigned char NumFats = iFAT16BootSector.NumberOfFats();
-	iFAT16BootSector.SetRootDirEntries();
-	unsigned short RootDirEntries = iFAT16BootSector.RootDirEntries();
-	iFAT16BootSector.ComputeTotalSectors(aPartitionSize);
-	unsigned short LowSectors = iFAT16BootSector.LowSectorsCount();
-	iFAT16BootSector.SetMedia();
-	unsigned char Media = iFAT16BootSector.Media();
-	iFAT16BootSector.ComputeFatSectors(aPartitionSize);
-	unsigned short FatSectors = iFAT16BootSector.FatSectors();
-	iFAT16BootSector.SetSectorsPerTrack();
-	unsigned short SectorPerTrack = iFAT16BootSector.SectorsPerTrack();
-	iFAT16BootSector.SetNumberOfHeads();
-	unsigned short NumberOfHeads = iFAT16BootSector.NumberOfHeads();
-	iFAT16BootSector.SetHiddenSectors();
-	unsigned int HiddenSectors = iFAT16BootSector.HiddenSectors();
-	unsigned int HighSectorsCount = iFAT16BootSector.HighSectorsCount();
-	iFAT16BootSector.SetBootSectorDriveNumber();
-	unsigned char BootSectorDriveNumber = iFAT16BootSector.BootSectorDriveNumber();
-	iFAT16BootSector.SetReservedByte();
-	unsigned char ReservedByte = iFAT16BootSector.ReservedByte();
-	iFAT16BootSector.SetBootSignature();
-	unsigned char BootSignature = iFAT16BootSector.BootSignature();
-	iFAT16BootSector.SetVolumeId();
-	unsigned int VolumeId = iFAT16BootSector.VolumeId();
-	iFAT16BootSector.SetVolumeLab(aConfigurableFatAttributes->iDriveVolumeLabel);
-	unsigned char* VolumeLab = iFAT16BootSector.VolumeLab();
-	iFAT16BootSector.SetFileSysType();
-	unsigned char* FileSysType = iFAT16BootSector.FileSysType();
-	//copying of boot sector values in to the array
-	iData = new unsigned char[BytesPerSector];
-	unsigned int pos = 0;
-	memcpy(&iData[pos],JmpBoot,3);
-	pos += 3;
-	memcpy(&iData[pos],OEMName,8);
-	pos += 8;
-	memcpy(&iData[pos],&BytesPerSector,2);
-	pos += 2;
-	memcpy(&iData[pos],&SectorsPerCluster,1);
-	pos += 1;
-	memcpy(&iData[pos],&ReservedSectors,2);
-	pos += 2;
-	memcpy(&iData[pos],&NumFats,1);
-	pos += 1;
-	memcpy(&iData[pos],&RootDirEntries,2);
-	pos += 2;
-	memcpy(&iData[pos],&LowSectors,2);
-	pos += 2;
-	memcpy(&iData[pos],&Media,1);
-	pos += 1;
-	memcpy(&iData[pos],&FatSectors,2);
-	pos += 2;
-	memcpy(&iData[pos],&SectorPerTrack,2);
-	pos += 2;
-	memcpy(&iData[pos],&NumberOfHeads,2);
-	pos += 2;
-	memcpy(&iData[pos],&HiddenSectors,4);
-	pos += 4;
-	memcpy(&iData[pos],&HighSectorsCount,4);
-	pos += 4;
-	memcpy(&iData[pos],&BootSectorDriveNumber,1);		
-	pos += 1;
-	memcpy(&iData[pos],&ReservedByte,1);
-	pos += 1;
-	memcpy(&iData[pos],&BootSignature,1);
-	pos += 1;
-	memcpy(&iData[pos],&VolumeId,4);
-	pos += 4;
-	memcpy(&iData[pos],VolumeLab,11);
-	pos += 11;
-	memcpy(&iData[pos],FileSysType,8);
-	pos += 8;
-	while(pos < BytesPerSector)
-	{
-		iData[pos] = 0;
-		pos++;
-	}
-	// Set sector [510] as 0xAA and [511] as 0x55 to mark the end of boot sector
-	iData[KSizeOfFatBootSector-2] = 0x55;
-	iData[KSizeOfFatBootSector-1] = 0xAA;
-	// It is perfectly ok for the last two bytes of the boot sector to also 
-	// have the signature 0xAA55.
-	iData[BytesPerSector-2] = 0x55;
-	iData[BytesPerSector-1] = 0xAA;
-
-
-	ComputeClusterSizeInBytes();
-	ComputeRootDirSectors();
-	ComputeBytesPerSector();
-	MessageHandler::ReportMessage (INFORMATION,BOOTSECTORCREATEMSG, "FAT16");
-}
-
-/**
-Writes the boot sector of a FAT 16 volume
-@param aOutPutStream handle to file stream	
-
-@internalComponent
-@released
-*/
-void CFat16FileSystem::WriteBootSector(ofstream& aOutPutStream)
-{
-	MessageHandler::ReportMessage (INFORMATION,BOOTSECTORWRITEMSG,"FAT16");
-	aOutPutStream.write(reinterpret_cast<char*>(&iData[0]),iFAT16BootSector.BytesPerSector());
-	aOutPutStream.flush();
-}
-/**
-Creates the FAT Table
-
-@internalComponent
-@released
-
-@param ofstream
-*/
-void CFat16FileSystem::CreateFatTable(ofstream& aOutPutStream)
-{
-	int FATSizeInBytes = (iFAT16BootSector.FatSectors()) * (iFAT16BootSector.BytesPerSector());
-	// Each FAT16 entries occupies 2 bytes, hence divided by 2
-	unsigned int totalFatEntries = FATSizeInBytes / 2;
-	unsigned short *FatTable = new unsigned short[totalFatEntries];
-	unsigned short int clusterCounter = 1;
-	int previousCluster;
-	FatTable[0] = KFat16FirstEntry;
-	/**Say cluster 5 starts at 5 and occupies clusters 7 and 9. The FAT table should have the 
-	value 7 at	cluster location 5, the value 9 at cluster 7 and 'eof' value at cluster 9.
-	Below algorithm serves this algorithm
-	*/
-	Iterator itr = iClustersPerEntry->begin();
-	while(itr != iClustersPerEntry->end())
-	{
-		previousCluster = itr->second;
-		if(iClustersPerEntry->count(itr->first) > 1)
-		{
-			for(unsigned int i = 1; i < iClustersPerEntry->count(itr->first); i++)
-			{
-				FatTable[previousCluster] = (unsigned short)(++itr)->second;
-				previousCluster = itr->second;
-				++clusterCounter;
-			}
-		}
-		FatTable[previousCluster] = EOF16;
-		itr++;
-		++clusterCounter;
-	}
-	// Each FAT16 entries occupies 2 bytes, hence multiply by 2
-	std::string aFatString(reinterpret_cast<char*>(FatTable),clusterCounter*2);
-	delete[] FatTable;
-	if(clusterCounter < totalFatEntries)
-	{
-		// Each FAT16 entries occupies 2 bytes, hence multiply by 2
-		aFatString.append((totalFatEntries - clusterCounter)*2, 0);
-	}
-	MessageHandler::ReportMessage (INFORMATION,FATTABLEWRITEMSG,
-								   "FAT16");
-	
-	// Write FAT table multiple times depending upon the No of FATS set.
-	unsigned int noOfFats = iFAT16BootSector.NumberOfFats();
-	for(unsigned int i=0; i<noOfFats; i++)
-	{
-		aOutPutStream.write(aFatString.c_str(),aFatString.length());
-	}
-	
-	aFatString.erase();
-	aOutPutStream.flush();
-}
-
-/**
-set the cluster size in bytes,iClusterSize
-
-@internalComponent
-@released
-*/
-void CFat16FileSystem::ComputeClusterSizeInBytes()
-{
-	iClusterSize = (iFAT16BootSector.SectorsPerCluster()) * (iFAT16BootSector.BytesPerSector());
-}
-
-/**
-set the count of sectors occupied by the root directory,iRootDirSectors.
-
-@internalComponent
-@released
-*/
-void CFat16FileSystem::ComputeRootDirSectors()
-{
-	iRootDirSectors = (iFAT16BootSector.RootDirEntries() * (KDefaultRootDirEntrySize) + 
-					  (iFAT16BootSector.BytesPerSector() - 1)) / iFAT16BootSector.BytesPerSector();
-}	
-
-/**
-Initialize the Bytes per Sector variable value.
-
-@internalComponent
-@released
-*/
-void CFat16FileSystem::ComputeBytesPerSector()
-{
-	iBytesPerSector = iFAT16BootSector.BytesPerSector();
-}
-
-
-/**
-Compute the total number of clusters in Data segment of the FAT volume
-
-@internalComponent
-@released
-*/
-void CFat16FileSystem::ComputeTotalClusters(Long64 aPartitionSize)
-{
-	unsigned long int iTotalDataSectors = iFAT16BootSector.TotalSectors(aPartitionSize) - 
-										  ((iFAT16BootSector.NumberOfFats() * iFAT16BootSector.FatSectors()) + 
-										  iRootDirSectors + iFAT16BootSector.ReservedSectors());
-	iTotalClusters = iTotalDataSectors / iFAT16BootSector.SectorsPerCluster();
-	if(iTotalClusters < KMinimumFat16Clusters)
-	{
-		throw ErrorHandler(BOOTSECTORERROR,"Low Partition Size",__FILE__,__LINE__);
-	}
-	if(iTotalClusters > KMaximumFat16Clusters)
-	{
-		throw ErrorHandler(BOOTSECTORERROR,"High Partition Size",__FILE__,__LINE__);
-	}
-	
-}
-
-/**
-This methods encapsulates the function call to write a complete FAT16 Image
-
-@internalComponent
-@released
-
-@param aPartitionSize partition size in bytes
-@param aNodeList Directory structure 
-@param aOutPutStream output stream for writing file image
-@param aImageFileName image file name 
-@param aLogFileName log file name 
-@param aConfigurableFatAttributes ConfigurableFatAttributes
-*/
-
-void CFat16FileSystem::Execute(Long64 aPartitionSize,EntryList aNodeList,ofstream& aOutPutStream,
-							   ConfigurableFatAttributes* aConfigurableFatAttributes)
-{
-	CDirRegion* dirRegionPtr = NULL;
-	try
-	{
-		CreateBootSector(aPartitionSize,aConfigurableFatAttributes);
-		ComputeTotalClusters(aPartitionSize);
-		WriteBootSector(aOutPutStream);
-		dirRegionPtr = new CDirRegion(aNodeList,this);
-		dirRegionPtr->Execute();
-		iClustersPerEntry = dirRegionPtr->GetClustersPerEntryMap();
-		CreateFatTable(aOutPutStream);
-		dirRegionPtr ->WriteClustersIntoFile(aOutPutStream);
-		delete dirRegionPtr ;
-	}
-	catch(ErrorHandler &aError)
-	{
-		delete dirRegionPtr;
-		//Re throw the same error message
-		throw ErrorHandler(aError.iMessageIndex,(char*)aError.iSubMessage.c_str(),(char*)aError.iFileName.c_str(),aError.iLineNumber);
-	}
-	/**
-	Irrespective of successful or unsuccessful data drive image generation ROFSBUILD
-	may try to generate images for successive ".oby" file input.
-	During this course unhandled exceptions may cause leaving some memory on heap 
-	unused. so the unhandled exceptions handling is used to free the memory allocated 
-	on heap. 
-	*/
-	catch(...)
-	{
-		delete dirRegionPtr;
-		throw ErrorHandler(UNKNOWNERROR, __FILE__, __LINE__);
-	}
-}
+/*
+* 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: 
+* CFat16FileSystem is the concrete class which is responsible for 
+* creating a FAT16 image. This class constitutes the method to 
+* create boot sector, FAT Table and data region of a FAT16 Image
+* @internalComponent
+* @released
+*
+*/
+
+#include"fat16filesystem.h"
+
+
+/**
+Initializes the boot sector of a FAT 16 volume
+
+@internalComponent
+@released
+
+@param aPartitionSize partition size in bytes
+@param aConfigurableFatAttributes ConfigurableFatAttributes
+*/
+void CFat16FileSystem::CreateBootSector(Long64 aPartitionSize,ConfigurableFatAttributes* aConfigurableFatAttributes)
+{
+ 	iFAT16BootSector.SetOEMName();
+	unsigned char* OEMName = iFAT16BootSector.OEMName();
+	iFAT16BootSector.SetJumpInstruction();
+	unsigned char* JmpBoot = iFAT16BootSector.JumpInstruction();
+	iFAT16BootSector.SetBytesPerSector(aConfigurableFatAttributes->iDriveSectorSize);
+	unsigned short BytesPerSector = (unsigned short)iFAT16BootSector.BytesPerSector();
+	iFAT16BootSector.ComputeSectorsPerCluster(aPartitionSize);
+	unsigned char SectorsPerCluster = iFAT16BootSector.SectorsPerCluster();
+	iFAT16BootSector.SetReservedSectors();
+	unsigned short ReservedSectors = iFAT16BootSector.ReservedSectors();
+	iFAT16BootSector.SetNumberOfFats(aConfigurableFatAttributes->iDriveNoOfFATs);
+	unsigned char NumFats = iFAT16BootSector.NumberOfFats();
+	iFAT16BootSector.SetRootDirEntries();
+	unsigned short RootDirEntries = iFAT16BootSector.RootDirEntries();
+	iFAT16BootSector.ComputeTotalSectors(aPartitionSize);
+	unsigned short LowSectors = iFAT16BootSector.LowSectorsCount();
+	iFAT16BootSector.SetMedia();
+	unsigned char Media = iFAT16BootSector.Media();
+	iFAT16BootSector.ComputeFatSectors(aPartitionSize);
+	unsigned short FatSectors = iFAT16BootSector.FatSectors();
+	iFAT16BootSector.SetSectorsPerTrack();
+	unsigned short SectorPerTrack = iFAT16BootSector.SectorsPerTrack();
+	iFAT16BootSector.SetNumberOfHeads();
+	unsigned short NumberOfHeads = iFAT16BootSector.NumberOfHeads();
+	iFAT16BootSector.SetHiddenSectors();
+	unsigned int HiddenSectors = iFAT16BootSector.HiddenSectors();
+	unsigned int HighSectorsCount = iFAT16BootSector.HighSectorsCount();
+	iFAT16BootSector.SetBootSectorDriveNumber();
+	unsigned char BootSectorDriveNumber = iFAT16BootSector.BootSectorDriveNumber();
+	iFAT16BootSector.SetReservedByte();
+	unsigned char ReservedByte = iFAT16BootSector.ReservedByte();
+	iFAT16BootSector.SetBootSignature();
+	unsigned char BootSignature = iFAT16BootSector.BootSignature();
+	iFAT16BootSector.SetVolumeId();
+	unsigned int VolumeId = iFAT16BootSector.VolumeId();
+	iFAT16BootSector.SetVolumeLab(aConfigurableFatAttributes->iDriveVolumeLabel);
+	unsigned char* VolumeLab = iFAT16BootSector.VolumeLab();
+	iFAT16BootSector.SetFileSysType();
+	unsigned char* FileSysType = iFAT16BootSector.FileSysType();
+	//copying of boot sector values in to the array
+	iData = new unsigned char[BytesPerSector];
+	unsigned int pos = 0;
+	memcpy(&iData[pos],JmpBoot,3);
+	pos += 3;
+	memcpy(&iData[pos],OEMName,8);
+	pos += 8;
+	memcpy(&iData[pos],&BytesPerSector,2);
+	pos += 2;
+	memcpy(&iData[pos],&SectorsPerCluster,1);
+	pos += 1;
+	memcpy(&iData[pos],&ReservedSectors,2);
+	pos += 2;
+	memcpy(&iData[pos],&NumFats,1);
+	pos += 1;
+	memcpy(&iData[pos],&RootDirEntries,2);
+	pos += 2;
+	memcpy(&iData[pos],&LowSectors,2);
+	pos += 2;
+	memcpy(&iData[pos],&Media,1);
+	pos += 1;
+	memcpy(&iData[pos],&FatSectors,2);
+	pos += 2;
+	memcpy(&iData[pos],&SectorPerTrack,2);
+	pos += 2;
+	memcpy(&iData[pos],&NumberOfHeads,2);
+	pos += 2;
+	memcpy(&iData[pos],&HiddenSectors,4);
+	pos += 4;
+	memcpy(&iData[pos],&HighSectorsCount,4);
+	pos += 4;
+	memcpy(&iData[pos],&BootSectorDriveNumber,1);		
+	pos += 1;
+	memcpy(&iData[pos],&ReservedByte,1);
+	pos += 1;
+	memcpy(&iData[pos],&BootSignature,1);
+	pos += 1;
+	memcpy(&iData[pos],&VolumeId,4);
+	pos += 4;
+	memcpy(&iData[pos],VolumeLab,11);
+	pos += 11;
+	memcpy(&iData[pos],FileSysType,8);
+	pos += 8;
+	while(pos < BytesPerSector)
+	{
+		iData[pos] = 0;
+		pos++;
+	}
+	// Set sector [510] as 0xAA and [511] as 0x55 to mark the end of boot sector
+	iData[KSizeOfFatBootSector-2] = 0x55;
+	iData[KSizeOfFatBootSector-1] = 0xAA;
+	// It is perfectly ok for the last two bytes of the boot sector to also 
+	// have the signature 0xAA55.
+	iData[BytesPerSector-2] = 0x55;
+	iData[BytesPerSector-1] = 0xAA;
+
+
+	ComputeClusterSizeInBytes();
+	ComputeRootDirSectors();
+	ComputeBytesPerSector();
+	MessageHandler::ReportMessage (INFORMATION,BOOTSECTORCREATEMSG, "FAT16");
+}
+
+/**
+Writes the boot sector of a FAT 16 volume
+@param aOutPutStream handle to file stream	
+
+@internalComponent
+@released
+*/
+void CFat16FileSystem::WriteBootSector(ofstream& aOutPutStream)
+{
+	MessageHandler::ReportMessage (INFORMATION,BOOTSECTORWRITEMSG,"FAT16");
+	aOutPutStream.write(reinterpret_cast<char*>(&iData[0]),iFAT16BootSector.BytesPerSector());
+	aOutPutStream.flush();
+}
+/**
+Creates the FAT Table
+
+@internalComponent
+@released
+
+@param ofstream
+*/
+void CFat16FileSystem::CreateFatTable(ofstream& aOutPutStream)
+{
+	int FATSizeInBytes = (iFAT16BootSector.FatSectors()) * (iFAT16BootSector.BytesPerSector());
+	// Each FAT16 entries occupies 2 bytes, hence divided by 2
+	unsigned int totalFatEntries = FATSizeInBytes / 2;
+	unsigned short *FatTable = new unsigned short[totalFatEntries];
+	unsigned short int clusterCounter = 1;
+	int previousCluster;
+	FatTable[0] = KFat16FirstEntry;
+	/**Say cluster 5 starts at 5 and occupies clusters 7 and 9. The FAT table should have the 
+	value 7 at	cluster location 5, the value 9 at cluster 7 and 'eof' value at cluster 9.
+	Below algorithm serves this algorithm
+	*/
+	Iterator itr = iClustersPerEntry->begin();
+	while(itr != iClustersPerEntry->end())
+	{
+		previousCluster = itr->second;
+		if(iClustersPerEntry->count(itr->first) > 1)
+		{
+			for(unsigned int i = 1; i < iClustersPerEntry->count(itr->first); i++)
+			{
+				FatTable[previousCluster] = (unsigned short)(++itr)->second;
+				previousCluster = itr->second;
+				++clusterCounter;
+			}
+		}
+		FatTable[previousCluster] = EOF16;
+		itr++;
+		++clusterCounter;
+	}
+	// Each FAT16 entries occupies 2 bytes, hence multiply by 2
+	string aFatString(reinterpret_cast<char*>(FatTable),clusterCounter*2);
+	delete[] FatTable;
+	if(clusterCounter < totalFatEntries)
+	{
+		// Each FAT16 entries occupies 2 bytes, hence multiply by 2
+		aFatString.append((totalFatEntries - clusterCounter)*2, 0);
+	}
+	MessageHandler::ReportMessage (INFORMATION,FATTABLEWRITEMSG,
+								   "FAT16");
+	
+	// Write FAT table multiple times depending upon the No of FATS set.
+	unsigned int noOfFats = iFAT16BootSector.NumberOfFats();
+	for(unsigned int i=0; i<noOfFats; i++)
+	{
+		aOutPutStream.write(aFatString.c_str(),aFatString.length());
+	}
+	
+	aFatString.erase();
+	aOutPutStream.flush();
+}
+
+/**
+set the cluster size in bytes,iClusterSize
+
+@internalComponent
+@released
+*/
+void CFat16FileSystem::ComputeClusterSizeInBytes()
+{
+	iClusterSize = (iFAT16BootSector.SectorsPerCluster()) * (iFAT16BootSector.BytesPerSector());
+}
+
+/**
+set the count of sectors occupied by the root directory,iRootDirSectors.
+
+@internalComponent
+@released
+*/
+void CFat16FileSystem::ComputeRootDirSectors()
+{
+	iRootDirSectors = (iFAT16BootSector.RootDirEntries() * (KDefaultRootDirEntrySize) + 
+					  (iFAT16BootSector.BytesPerSector() - 1)) / iFAT16BootSector.BytesPerSector();
+}	
+
+/**
+Initialize the Bytes per Sector variable value.
+
+@internalComponent
+@released
+*/
+void CFat16FileSystem::ComputeBytesPerSector()
+{
+	iBytesPerSector = iFAT16BootSector.BytesPerSector();
+}
+
+
+/**
+Compute the total number of clusters in Data segment of the FAT volume
+
+@internalComponent
+@released
+*/
+void CFat16FileSystem::ComputeTotalClusters(Long64 aPartitionSize)
+{
+	unsigned long int iTotalDataSectors = iFAT16BootSector.TotalSectors(aPartitionSize) - 
+										  ((iFAT16BootSector.NumberOfFats() * iFAT16BootSector.FatSectors()) + 
+										  iRootDirSectors + iFAT16BootSector.ReservedSectors());
+	iTotalClusters = iTotalDataSectors / iFAT16BootSector.SectorsPerCluster();
+	if(iTotalClusters < KMinimumFat16Clusters)
+	{
+		throw ErrorHandler(BOOTSECTORERROR,"Low Partition Size",__FILE__,__LINE__);
+	}
+	if(iTotalClusters > KMaximumFat16Clusters)
+	{
+		throw ErrorHandler(BOOTSECTORERROR,"High Partition Size",__FILE__,__LINE__);
+	}
+	
+}
+
+/**
+This methods encapsulates the function call to write a complete FAT16 Image
+
+@internalComponent
+@released
+
+@param aPartitionSize partition size in bytes
+@param aNodeList Directory structure 
+@param aOutPutStream output stream for writing file image
+@param aImageFileName image file name 
+@param aLogFileName log file name 
+@param aConfigurableFatAttributes ConfigurableFatAttributes
+*/
+
+void CFat16FileSystem::Execute(Long64 aPartitionSize,EntryList aNodeList,ofstream& aOutPutStream,
+							   ConfigurableFatAttributes* aConfigurableFatAttributes)
+{
+	CDirRegion* dirRegionPtr = NULL;
+	try
+	{
+		CreateBootSector(aPartitionSize,aConfigurableFatAttributes);
+		ComputeTotalClusters(aPartitionSize);
+		WriteBootSector(aOutPutStream);
+		dirRegionPtr = new CDirRegion(aNodeList,this);
+		dirRegionPtr->Execute();
+		iClustersPerEntry = dirRegionPtr->GetClustersPerEntryMap();
+		CreateFatTable(aOutPutStream);
+		dirRegionPtr ->WriteClustersIntoFile(aOutPutStream);
+		delete dirRegionPtr ;
+	}
+	catch(ErrorHandler &aError)
+	{
+		delete dirRegionPtr;
+		//Re throw the same error message
+		throw ErrorHandler(aError.iMessageIndex,(char*)aError.iSubMessage.c_str(),(char*)aError.iFileName.c_str(),aError.iLineNumber);
+	}
+	/**
+	Irrespective of successful or unsuccessful data drive image generation ROFSBUILD
+	may try to generate images for successive ".oby" file input.
+	During this course unhandled exceptions may cause leaving some memory on heap 
+	unused. so the unhandled exceptions handling is used to free the memory allocated 
+	on heap. 
+	*/
+	catch(...)
+	{
+		delete dirRegionPtr;
+		throw ErrorHandler(UNKNOWNERROR, __FILE__, __LINE__);
+	}
+}