sl@0: // Copyright (c) 1998-2009 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 the License "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: // f32\sfat\sl_scan.cpp
sl@0: // ScanDrive code, specific for EFAT.FSY
sl@0: // 
sl@0: //
sl@0: 
sl@0: /**
sl@0:  @file
sl@0:  @internalTechnology
sl@0: */
sl@0: 
sl@0: //!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
sl@0: //!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
sl@0: //!!
sl@0: //!! WARNING!! DO NOT edit this file !! '\sfat' component is obsolete and is not being used. '\sfat32'replaces it
sl@0: //!!
sl@0: //!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
sl@0: //!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
sl@0: 
sl@0: 
sl@0: //#define DEBUG_SCANDRIVE
sl@0: 
sl@0: #include "sl_std.h"
sl@0: #include "sl_scandrv.h"
sl@0: 
sl@0: const TInt KEndOfDirectory          = 0xFFFF;   ///< End of directory marker
sl@0: const TInt KMaxScanDepth            = 20;       ///< Maximum scan depth of to avoid stack over flow 
sl@0: const TInt KClusterListGranularity  = 8;        ///< Granularity of cluster list used for storage of clusters when KMaxScanDepth is reached
sl@0: 
sl@0: /**
sl@0: Creates a CScanDrive
sl@0: 
sl@0: @param aMount The owning mount
sl@0: */
sl@0: CScanDrive* CScanDrive::NewL(CFatMountCB* aMount)
sl@0:     {
sl@0:     if(aMount==NULL)
sl@0:         User::Leave(KErrArgument);
sl@0:     CScanDrive* self=new (ELeave) CScanDrive();
sl@0:     CleanupStack::PushL(self);
sl@0:     self->ConstructL(aMount);
sl@0:     CleanupStack::Pop();
sl@0:     return self;
sl@0:     }
sl@0: 
sl@0: 
sl@0: CScanDrive::CScanDrive()
sl@0: //
sl@0: // Constructor
sl@0: //
sl@0:     {
sl@0:     }
sl@0: 
sl@0: 
sl@0: CScanDrive::~CScanDrive()
sl@0: //
sl@0: // Destructor
sl@0: //
sl@0:     {
sl@0:     delete iNewFat;
sl@0:     for(TInt i=0;i<KMaxArrayDepth && iClusterListArray[i]!=NULL;++i)
sl@0:         {
sl@0:         iClusterListArray[i]->Close();
sl@0:         delete iClusterListArray[i];
sl@0:         }
sl@0:     }
sl@0: 
sl@0: 
sl@0: void CScanDrive::ConstructL(CFatMountCB* aMount)
sl@0: //
sl@0: // Create the new fat and initalise
sl@0: //
sl@0:     {
sl@0:     iMount=aMount;
sl@0:     iNewFat=CCheckFatTable::NewL(aMount);
sl@0:     iNewFat->InitializeL();
sl@0:     }
sl@0: 
sl@0: 
sl@0: TBool CScanDrive::AlreadyExistsL(TInt aCluster)const
sl@0: //
sl@0: //  Return ETrue if aCluster in the new fat contains a non-zero entry
sl@0: //
sl@0:     {
sl@0:     return(iNewFat->ReadL(aCluster)!=0);
sl@0:     }
sl@0: 
sl@0: 
sl@0: TBool CScanDrive::IsEndOfRootDir(const TEntryPos& aPos)const
sl@0: //
sl@0: // Return ETrue if aPos is the last entry in the root directory
sl@0: //
sl@0:     {
sl@0:     return(iMount->IsRootDir(aPos)&&(iMount->StartOfRootDirInBytes()+aPos.iPos==(iMount->RootDirEnd()-KSizeOfFatDirEntry)));
sl@0:     }
sl@0: 
sl@0: /**
sl@0: @param aVal Value of the cluster to be tested
sl@0: @return ETrue if aVal is the end of cluster marker
sl@0: */
sl@0: TBool CScanDrive::IsEofF(TInt aVal)const 
sl@0:     {
sl@0:     return iMount->IsEndOfClusterCh(aVal);
sl@0:     }
sl@0: 
sl@0: /**
sl@0: @return True if a directory error has been found
sl@0: */
sl@0: TBool CScanDrive::IsDirError()const
sl@0:     {
sl@0:     return(iDirError!=0);
sl@0:     }
sl@0: 
sl@0: 
sl@0: 
sl@0: /**
sl@0:     After StartL() and finishing allows us to know if there were any problems at all.
sl@0:     The client may wish to remount the filesystem if there were errors.
sl@0: 
sl@0:     @return EFalse if there were no problems in FS.
sl@0: */
sl@0: TBool CScanDrive::ProblemsDiscovered() const
sl@0: {
sl@0:     return IsDirError() || iFoundProblems;
sl@0: }
sl@0: 
sl@0: /**
sl@0:     Sets the flag indicating than there are errors in filesystem structure
sl@0:     See ProblemsDiscovered()
sl@0: */
sl@0: void CScanDrive::IndicateErrorsFound()
sl@0: {
sl@0:     iFoundProblems = ETrue;
sl@0: }
sl@0: 
sl@0: 
sl@0: 
sl@0: /**
sl@0: Start point for scan drive also fixes up errors 
sl@0: 
sl@0: @return The result of the scan
sl@0: @leave 
sl@0: */
sl@0: TInt CScanDrive::StartL()
sl@0:     {
sl@0:     __PRINT(_L("CScanDrive::StartL"));
sl@0:     // check directory structure
sl@0:     CheckDirStructureL();
sl@0: #if defined(DEBUG_SCANDRIVE)
sl@0:     CompareFatsL();
sl@0: #endif
sl@0:     // fix error in directory structure
sl@0:     if(IsDirError())
sl@0:         FixupDirErrorL();
sl@0:     // flush new fat
sl@0:     WriteNewFatsL();
sl@0: #if defined(DEBUG_SCANDRIVE)
sl@0:     PrintErrors();
sl@0: #endif
sl@0:     return KErrNone;
sl@0:     }
sl@0: 
sl@0: /**
sl@0: Fix errors detected by the drive scan
sl@0: 
sl@0: @leave System wide error code
sl@0: */
sl@0: void CScanDrive::FixupDirErrorL()
sl@0:     {
sl@0:     if(!IsDirError())
sl@0:         return;
sl@0:     if(iDirError==EScanMatchingEntry)
sl@0:         {
sl@0:         FindSameStartClusterL();
sl@0:         FixMatchingEntryL();
sl@0:         }
sl@0:     else
sl@0:         {
sl@0:         FixPartEntryL();
sl@0:         }
sl@0: 
sl@0:     IndicateErrorsFound(); //-- indicate that we have found errors
sl@0:     }
sl@0: 
sl@0: /**
sl@0: Find positions of entries with same start cluster for error correction, searches
sl@0: the whole volume. Starts at the root directory. 
sl@0: 
sl@0: @leave System wide error code
sl@0: */
sl@0: void CScanDrive::FindSameStartClusterL()
sl@0:     {
sl@0:     TInt err=FindStartClusterL(0);
sl@0:     if(err==KErrNone)
sl@0:         return;
sl@0:     for(TInt i=0;i<KMaxArrayDepth && iClusterListArray[i]!=NULL;++i)
sl@0:         {
sl@0:         RArray<TInt>* clusterList=iClusterListArray[i];
sl@0:         for(TInt j=0;j<clusterList->Count();++j)
sl@0:             {
sl@0:             iRecursiveDepth=0;
sl@0:             err=FindStartClusterL((*clusterList)[j]);
sl@0:             if(err==KErrNone)
sl@0:                 return;
sl@0:             }
sl@0:         }
sl@0:     __ASSERT_ALWAYS(err==KErrNone,User::Leave(KErrNotFound));
sl@0:     }
sl@0: /**
sl@0: Scan through directory structure looking for start cluster found in iMatching
sl@0: 
sl@0: @param aDirCluster Start cluster for scan to start
sl@0: @return System wide error value
sl@0: @leave 
sl@0: */
sl@0: TInt CScanDrive::FindStartClusterL(TInt aDirCluster)
sl@0:     {
sl@0:     __PRINT1(_L("CScanDrive::FindStartCluster dirCluster=%d"),aDirCluster);
sl@0:     __ASSERT_ALWAYS(aDirCluster>=0,User::Leave(KErrCorrupt));
sl@0:     if(++iRecursiveDepth==KMaxScanDepth)
sl@0:         {
sl@0:         --iRecursiveDepth;
sl@0:         return(KErrNotFound);
sl@0:         }
sl@0:     TEntryPos entryPos(aDirCluster,0);
sl@0:     TInt dirEntries=0;
sl@0:     FOREVER
sl@0:         {
sl@0:         TFatDirEntry entry;
sl@0:         iMount->ReadDirEntryL(entryPos,entry);
sl@0:         if(entry.IsParentDirectory()||entry.IsCurrentDirectory()||entry.IsErased())
sl@0:             {
sl@0:             if(IsEndOfRootDir(entryPos))
sl@0:                 break;
sl@0:             iMount->MoveToNextEntryL(entryPos);
sl@0:             continue;
sl@0:             }
sl@0:         if(entry.IsEndOfDirectory())
sl@0:             break;
sl@0:         TBool isComplete;
sl@0:         TEntryPos vfatPos=entryPos;
sl@0:         isComplete=MoveToVFatEndL(entryPos,entry,dirEntries);
sl@0:         __ASSERT_ALWAYS(isComplete,User::Leave(KErrBadName));
sl@0:         TInt err=CheckEntryClusterL(entry,vfatPos);
sl@0:         if(err==KErrNone)
sl@0:             {
sl@0:             --iRecursiveDepth;
sl@0:             return(err);
sl@0:             }
sl@0:         if(IsEndOfRootDir(entryPos))
sl@0:             break;
sl@0:         iMount->MoveToNextEntryL(entryPos);
sl@0:         }
sl@0:     --iRecursiveDepth;
sl@0:     return(KErrNotFound);
sl@0:     }
sl@0: 
sl@0: /**
sl@0: Procces aEntry to find matching start cluster
sl@0: 
sl@0: @param aEntry Directory entry to check
sl@0: @param aEntryPos Position of directory to check
sl@0: @return System wide error value
sl@0: @leave 
sl@0: */
sl@0: TInt CScanDrive::CheckEntryClusterL(const TFatDirEntry& aEntry, const TEntryPos& aEntryPos)
sl@0:     {
sl@0:     __PRINT(_L("CScanDrive::CheckEntryClusterL"));
sl@0:     if(iMount->StartCluster(aEntry)==iMatching.iStartCluster)
sl@0:         {
sl@0:         TBool complete=AddMatchingEntryL(aEntryPos);
sl@0:         if(complete)
sl@0:             return(KErrNone);
sl@0:         }
sl@0:     else if(aEntry.Attributes()&KEntryAttDir)
sl@0:         return(FindStartClusterL(iMount->StartCluster(aEntry)));
sl@0:     return(KErrNotFound);
sl@0:     }
sl@0: 
sl@0: /**
sl@0: Checks directory strucutre for errors, can be considered the start point of the scan.  
sl@0: Handles recursion depth to avoid stack overflow.
sl@0: 
sl@0: @leave System wide error code
sl@0: */
sl@0: void CScanDrive::CheckDirStructureL()
sl@0:     {
sl@0:     CheckDirL(iMount->RootIndicator());
sl@0:     // Due to recursive nature of CheckDirL when a depth of
sl@0:     // KMaxScanDepth is reached clusters are stored in a list
sl@0:     // and passed into CheckDirL afresh
sl@0:     for(TInt i=0;i<KMaxArrayDepth && iClusterListArray[i]!=NULL;++i)
sl@0:         {
sl@0:         RArray<TInt>* clusterList=iClusterListArray[i];
sl@0:         ++iListArrayIndex;
sl@0:         for(TInt j=0;j<clusterList->Count();++j)
sl@0:             {
sl@0:             iRecursiveDepth=0;
sl@0:             CheckDirL((*clusterList)[j]);
sl@0:             }
sl@0:         }
sl@0:     }
sl@0: /**
sl@0: Function is called recursively with Process entry untill the whole volume has been scanned.
sl@0: Each directory entry is scanned for errors, these are recorded for later fixing. 
sl@0: 
sl@0: @param aCluster Directory cluster to start checking
sl@0: @leave System wide error codes
sl@0: */
sl@0: void CScanDrive::CheckDirL(TInt aCluster)
sl@0:     {
sl@0:     __PRINT1(_L("CScanDrive::CheckDirL aCluster=%d"),aCluster);
sl@0:     __ASSERT_ALWAYS(aCluster>=0,User::Leave(KErrCorrupt));
sl@0:     // check depth of recursion
sl@0:     if(++iRecursiveDepth==KMaxScanDepth)
sl@0:         {
sl@0:         AddToClusterListL(aCluster);
sl@0:         --iRecursiveDepth;
sl@0:         return;
sl@0:         }
sl@0: #if defined(DEBUG_SCANDRIVE)
sl@0:     ++iDirsChecked;
sl@0: #endif
sl@0:     TEntryPos entryPos(aCluster,0);
sl@0:     TInt dirEntries=0;
sl@0:     FOREVER
sl@0:         {
sl@0:         TFatDirEntry entry;
sl@0:         iMount->ReadDirEntryL(entryPos,entry);
sl@0:         if(!iMount->IsEndOfClusterCh(entryPos.iCluster))
sl@0:             ++dirEntries;
sl@0:         if(entry.IsParentDirectory()||entry.IsCurrentDirectory()||entry.IsErased())
sl@0:             {
sl@0:             if(IsEndOfRootDir(entryPos))
sl@0:                 break;
sl@0:             iMount->MoveToNextEntryL(entryPos);
sl@0:             continue;
sl@0:             }
sl@0:         if(entry.IsEndOfDirectory())
sl@0:             {
sl@0:             if(aCluster)    
sl@0:                 WriteClusterChainL(aCluster,dirEntries<<KSizeOfFatDirEntryLog2);
sl@0:             break;
sl@0:             }
sl@0:         TEntryPos origPos=entryPos;
sl@0:         TFatDirEntry origEntry=entry;
sl@0:         TInt origDirEntries=dirEntries;
sl@0:         TBool isComplete;
sl@0:         isComplete=MoveToVFatEndL(entryPos,entry,dirEntries);
sl@0:         // Only assume that this is a corrupted VFAT entry if the VFAT attributes are set; 
sl@0:         // assuming a non-VFAT corrupted entry is a VFAT entry is dangerous as we then assume that the 
sl@0:         // first byte is a count of entries to skip, thus completely invalidating the next <n> directories.
sl@0:         if (!isComplete && origEntry.IsVFatEntry())
sl@0:             {
sl@0:             AddPartialVFatL(origPos,origEntry);
sl@0:             if(entryPos.iCluster!=KEndOfDirectory)
sl@0:                 {
sl@0:                 TInt toMove=origEntry.NumFollowing()-(dirEntries-origDirEntries);
sl@0:                 if(toMove)
sl@0:                     MovePastEntriesL(entryPos,entry,toMove,dirEntries);
sl@0:                 }
sl@0:             else
sl@0:                 {
sl@0:                 // we fell off the end of the directory file, so just strip this
sl@0:                 // incomplete long file name entry
sl@0:                 dirEntries = origDirEntries;
sl@0:                 }
sl@0:             }
sl@0:         else
sl@0:             ProcessEntryL(entry);
sl@0:         if(IsEndOfRootDir(entryPos))
sl@0:             break;
sl@0:         iMount->MoveToNextEntryL(entryPos);
sl@0:         }
sl@0:     --iRecursiveDepth;
sl@0:     }
sl@0: 
sl@0: /**
sl@0: Process non trivial entries, such as files, if they are correct by filling out their 
sl@0: cluster allocation in the bit packed Fat table. If it comes accross a directory 
sl@0: CheckDirL will be called.
sl@0: 
sl@0: @param aEntry Directory entry to check
sl@0: @leave System wide error code
sl@0: */
sl@0: void CScanDrive::ProcessEntryL(const TFatDirEntry& aEntry)
sl@0:     {
sl@0:     __PRINT(_L("CScanDrive::ProcessEntryL"));
sl@0:     TInt entryAtt=aEntry.Attributes();
sl@0:     __ASSERT_ALWAYS(!(entryAtt&~KEntryAttMaskSupported)&&!aEntry.IsErased(),User::Leave(KErrCorrupt));
sl@0:     if(!(entryAtt&(KEntryAttDir|KEntryAttVolume)) && iMount->StartCluster(aEntry)>0)
sl@0:         WriteClusterChainL(iMount->StartCluster(aEntry),aEntry.Size());
sl@0:     else if(entryAtt&KEntryAttDir)
sl@0:         CheckDirL(iMount->StartCluster(aEntry));
sl@0:     }
sl@0: 
sl@0: /**
sl@0: Writes out the cluster chain for a correct file or directory, checks that the cluster 
sl@0: has not already been used and that the correct number of clusters are allocated for the 
sl@0: size of file. Registers cluster as used if correct
sl@0: 
sl@0: @param aCluster Cluster chain start point
sl@0: @param aSizeInBytes Size of the file or directory in bytes
sl@0: @leave System wide error values
sl@0: */
sl@0: void CScanDrive::WriteClusterChainL(TInt aCluster,TInt aSizeInBytes)
sl@0: //
sl@0: // Mark off in the new fat the clusters used by entry with start cluster of aCluster
sl@0: //
sl@0:     {
sl@0: 
sl@0:     IndicateErrorsFound(); //-- indicate that we have found errors
sl@0: 
sl@0:     __PRINT1(_L("CScanDrive::WriteClusterChainL starting at %d"),aCluster);
sl@0:     __ASSERT_ALWAYS(aCluster>0 && aSizeInBytes>=0,User::Leave(KErrCorrupt));
sl@0:     TInt clusterCount;
sl@0:     if(aSizeInBytes==0)
sl@0:         clusterCount=1;
sl@0:     else
sl@0:         clusterCount=(aSizeInBytes+(1<<iMount->ClusterSizeLog2())-1)>>iMount->ClusterSizeLog2();
sl@0:     TInt startCluster=aCluster;
sl@0:     while(clusterCount)
sl@0:         {
sl@0:         if(AlreadyExistsL(aCluster))
sl@0:             {
sl@0:             __ASSERT_ALWAYS(!IsDirError()&&iMatching.iStartCluster==0&&aCluster==startCluster,User::Leave(KErrCorrupt));
sl@0:             iMatching.iStartCluster=aCluster;
sl@0:             iDirError=EScanMatchingEntry;
sl@0:             return;
sl@0:             }
sl@0:         if(clusterCount==1)
sl@0:             {
sl@0:             iNewFat->WriteFatEntryEofFL(aCluster);
sl@0:             return;
sl@0:             }
sl@0:         else
sl@0:             {
sl@0:             TInt clusterVal;
sl@0:             clusterVal=iMount->FAT().ReadL(aCluster);
sl@0:             __ASSERT_ALWAYS(!IsEofF(clusterVal) && clusterVal!=0,User::Leave(KErrCorrupt));
sl@0:             iNewFat->WriteL(aCluster,clusterVal);
sl@0:             aCluster=clusterVal;
sl@0:             --clusterCount;
sl@0:             }
sl@0:         }
sl@0:     }
sl@0: 
sl@0: /**
sl@0: Move to dos entry, checking all vfat entry ID numbers are in sequence.
sl@0: Assumes aEntry is not erased
sl@0: 
sl@0: @param aPos Position of the entry to move from, returns with new position
sl@0: @param aEntry The Dos entry after the Vfat entries on return
sl@0: @param aDirLength Running total of the length of the directory in entries
sl@0: @leave System wide error codes
sl@0: @return EFalse if not valid vfat entries or dos entry, else returns ETrue
sl@0: */
sl@0: TBool CScanDrive::MoveToVFatEndL(TEntryPos& aPos,TFatDirEntry& aEntry,TInt& aDirLength)
sl@0:     {
sl@0:     __PRINT2(_L("CScanDrive::MoveToVFatEndL cluster=%d,pos=%d"),aPos.iCluster,aPos.iPos);
sl@0:     if(!aEntry.IsVFatEntry())
sl@0:         return IsDosEntry(aEntry);
sl@0:     TInt toFollow=aEntry.NumFollowing();
sl@0:     __ASSERT_ALWAYS(toFollow>0&&!aEntry.IsErased(),User::Leave(KErrCorrupt));
sl@0:     FOREVER
sl@0:         {
sl@0:         iMount->MoveToNextEntryL(aPos);
sl@0:         iMount->ReadDirEntryL(aPos,aEntry);
sl@0:         ++aDirLength;
sl@0:         --toFollow;
sl@0:         if(!toFollow)
sl@0:             break;
sl@0:         if(!IsValidVFatEntry(aEntry,toFollow))
sl@0:             return(EFalse);
sl@0:         }
sl@0:     return(IsDosEntry(aEntry));
sl@0:     }
sl@0: 
sl@0: /**
sl@0: Check if an entry is valid VFat
sl@0: 
sl@0: @param aEntry Entry to check
sl@0: @param aPrevNum Number into VFat entries for a dos entry to ensure in correct position
sl@0: @return ETrue if aEntry is a valid vfat entry
sl@0: */
sl@0: TBool CScanDrive::IsValidVFatEntry(const TFatDirEntry& aEntry, TInt aPrevNum)const
sl@0:     {
sl@0:     if(aEntry.IsErased()||!aEntry.IsVFatEntry())
sl@0:         return(EFalse);
sl@0:     return(aEntry.NumFollowing()==aPrevNum);
sl@0:     }
sl@0: 
sl@0: /**
sl@0: Check if an entry is a Dos entry
sl@0: 
sl@0: @param aEntry Entry to check
sl@0: @return ETrue if aEntry is a dos entry
sl@0: */
sl@0: TBool CScanDrive::IsDosEntry(const TFatDirEntry& aEntry)const
sl@0:     {
sl@0:     TBool res = !(aEntry.Attributes()&~KEntryAttMaskSupported) && !aEntry.IsErased() && !aEntry.IsVFatEntry() && !aEntry.IsEndOfDirectory();
sl@0:     return res;
sl@0:     } 
sl@0: 
sl@0: /**
sl@0: Add partial entry to iPartEntry under the error condition of not all Vfat entries 
sl@0: being present
sl@0: 
sl@0: @param aStartPos Position of the Dos entry associated with the VFat entries
sl@0: @param aEntry Directory Entry of the Dos entry associated with the VFat entries
sl@0: @leave KErrCorrupt Occurs if the entry is not valid
sl@0: */
sl@0: void CScanDrive::AddPartialVFatL(const TEntryPos& aStartPos, const TFatDirEntry& aEntry)
sl@0:     {
sl@0:     __PRINT2(_L("CScanDrive::AddPartialVFatL cluster=%d pos=%d"),aStartPos.iCluster,aStartPos.iPos);
sl@0:     __ASSERT_ALWAYS(!IsDirError(),User::Leave(KErrCorrupt));
sl@0:     iPartEntry.iEntryPos=aStartPos;
sl@0:     iPartEntry.iEntry=aEntry;
sl@0:     iDirError=EScanPartEntry;
sl@0:     }
sl@0: 
sl@0: /**
sl@0: Add entry position to iMatching
sl@0: 
sl@0: @param aEntryPos Position of the entry with the matching entry
sl@0: @leave KErrCorrupt if the start cluster is 0 or more that two matching entries occurs
sl@0: @return 
sl@0: */
sl@0: TBool CScanDrive::AddMatchingEntryL(const TEntryPos& aEntryPos)
sl@0:     {
sl@0:     __PRINT2(_L("CScanDrive::AddMatchingEntryL cluster=%d pos=%d"),aEntryPos.iCluster,aEntryPos.iPos);
sl@0:     __ASSERT_ALWAYS(iMatching.iStartCluster>0 && iMatching.iCount<KMaxMatchingEntries,User::Leave(KErrCorrupt));
sl@0:     iMatching.iEntries[iMatching.iCount++]=aEntryPos;
sl@0:     return iMatching.iCount==KMaxMatchingEntries;
sl@0:     }
sl@0: 
sl@0: 
sl@0: /**
sl@0: Scan for differnces in the new and old FAT table writing them to media if discovered
sl@0: 
sl@0: @leave System wide error codes
sl@0: */
sl@0: void CScanDrive::WriteNewFatsL()
sl@0: //
sl@0: // Write the new fat table to disk
sl@0: //
sl@0:     {
sl@0:     if(iNewFat->FlushL())
sl@0:         IndicateErrorsFound(); //-- indicate that we have found errors       
sl@0:     }
sl@0: 
sl@0: TInt CScanDrive::GetReservedidL(TEntryPos aVFatPos)
sl@0: //
sl@0: // Return the id found in reserved2 field of dos entry
sl@0: //
sl@0:     {
sl@0:     __PRINT(_L("CScanDrive::GetReservedidL"));
sl@0:     TFatDirEntry entry;
sl@0:     iMount->ReadDirEntryL(aVFatPos,entry);
sl@0:     if(!IsDosEntry(entry))
sl@0:         {
sl@0:         TInt toMove=entry.NumFollowing();
sl@0:         while(toMove--)
sl@0:             iMount->MoveToNextEntryL(aVFatPos);
sl@0:         iMount->ReadDirEntryL(aVFatPos,entry);
sl@0:         }
sl@0:     return(entry.RuggedFatEntryId());
sl@0:     }
sl@0: 
sl@0: /**
sl@0: Erase part entry found in iPartEntry
sl@0: 
sl@0: @leave System wide error code
sl@0: */
sl@0: void CScanDrive::FixPartEntryL()
sl@0:     {
sl@0:     __PRINT2(_L("CScanDrive::FixPartEntryL cluster=%d,pos=%d"),iPartEntry.iEntryPos.iCluster,iPartEntry.iEntryPos.iPos);
sl@0:     iMount->EraseDirEntryL(iPartEntry.iEntryPos,iPartEntry.iEntry);
sl@0:     IndicateErrorsFound(); //-- indicate that we have found errors
sl@0:     }
sl@0:     
sl@0: /**
sl@0: Delete entry with largest value in the reserved2 section(bytes 20 and 21) of dos entry
sl@0:     
sl@0: @leave System wide error code
sl@0: */
sl@0: void CScanDrive::FixMatchingEntryL()
sl@0:     {
sl@0:     __PRINT1(_L("CScanDrive::FixMatchingEntryL() start cluster=%d"),iMatching.iStartCluster);
sl@0:     __ASSERT_ALWAYS(iMatching.iCount==KMaxMatchingEntries,User::Leave(KErrCorrupt));
sl@0:     TInt idOne=GetReservedidL(iMatching.iEntries[0]);
sl@0:     TInt idTwo=GetReservedidL(iMatching.iEntries[1]);
sl@0:     TFatDirEntry entry;
sl@0:     TInt num=idOne>idTwo?0:1;
sl@0:     iMount->ReadDirEntryL(iMatching.iEntries[num],entry);
sl@0:     iMount->EraseDirEntryL(iMatching.iEntries[num],entry);
sl@0:     IndicateErrorsFound(); //-- indicate that we have found errors
sl@0:     }
sl@0: /**
sl@0: Move past specified number of entries
sl@0: 
sl@0: @param aEntryPos Start position to move from, updated as move takes place
sl@0: @param aEntry Directory entry moved to
sl@0: @param aToMove Number of entries to move through
sl@0: @param aDirEntries Number of entries moved, updated as move takes place
sl@0: @leave System wide error code
sl@0: */
sl@0: void CScanDrive::MovePastEntriesL(TEntryPos& aEntryPos,TFatDirEntry& aEntry,TInt aToMove,TInt& aDirEntries)
sl@0:     {
sl@0:     while(aToMove-- && aEntryPos.iCluster!=KEndOfDirectory)
sl@0:         {
sl@0:         iMount->MoveToNextEntryL(aEntryPos);
sl@0:         ++aDirEntries;
sl@0:         }
sl@0:     iMount->ReadDirEntryL(aEntryPos,aEntry);
sl@0:     }
sl@0: 
sl@0: /**
sl@0: Adds aCluster to cluster list array so that it may be revisited later, avoids stack 
sl@0: over flow
sl@0: 
sl@0: @param aCluster Directory cluster number to add to the list
sl@0: @leave KErrNoMemory If allocation fails
sl@0: */
sl@0: void CScanDrive::AddToClusterListL(TInt aCluster)
sl@0:     {
sl@0:     if(iListArrayIndex>=KMaxArrayDepth)
sl@0:         return;
sl@0:     if(iClusterListArray[iListArrayIndex]==NULL)
sl@0:         iClusterListArray[iListArrayIndex]=new(ELeave) RArray<TInt>(KClusterListGranularity);
sl@0:     iClusterListArray[iListArrayIndex]->Append(aCluster);
sl@0:     }
sl@0: 
sl@0: 
sl@0: #if defined(DEBUG_SCANDRIVE)
sl@0: void CScanDrive::CompareFatsL()
sl@0: //
sl@0: // Compare new fat and first fat table
sl@0: //  
sl@0:     {
sl@0:     __PRINT(_L("CScanDrive::CompareFatsL()"));
sl@0:     TInt maxClusters;
sl@0:     maxClusters=iMount->UsableClusters();
sl@0:     for(TInt i=KFatFirstSearchCluster; i<maxClusters; ++i)
sl@0:         {
sl@0:         TInt realFat=iMount->FAT().ReadL(i);
sl@0:         TInt newFat=iNewFat->ReadL(i);
sl@0:         if(realFat!=newFat)
sl@0:             {
sl@0:             if(realFat!=0 && newFat==0)
sl@0:                 __PRINT1(_L("Lost cluster=%d\n"),i)
sl@0:             else if((realFat>0 && !IsEofF(realFat)) && IsEofF(newFat))
sl@0:                 __PRINT1(_L("Hanging cluster = %d\n"),i)
sl@0:             else if(realFat==0 && newFat>0)
sl@0:                 __PRINT1(_L("Unflushed cluster = %d\n"),i)
sl@0:             else
sl@0:                 User::Leave(KErrCorrupt);
sl@0:             }
sl@0:         }
sl@0:     }   
sl@0: 
sl@0: 
sl@0: /** 
sl@0: For debug purposes, print errors found as debug output 
sl@0:  
sl@0: */ 
sl@0: void CScanDrive::PrintErrors()
sl@0:     {
sl@0:     __PRINT1(_L("Directories visisted = %d\n"),iDirsChecked);
sl@0:     if(iDirError==EScanPartEntry)
sl@0:         __PRINT2(_L("Part entry-dir cluster=%d,dir pos=%d,\n"),iPartEntry.iEntryPos.iCluster,iPartEntry.iEntryPos.iPos)
sl@0:     else if(iDirError==EScanMatchingEntry)
sl@0:         {
sl@0:         __PRINT1(_L("Matching cluster - cluster no=%d\n"),iMatching.iStartCluster);
sl@0:         __PRINT2(_L("\tcluster 1 - dir cluster=%d,dir pos=%d\n"),iMatching.iEntries[0].iCluster,iMatching.iEntries[0].iPos);
sl@0:         __PRINT2(_L("\tcluster 2 - dir cluster=%d,dir pos=%d\n"),iMatching.iEntries[1].iCluster,iMatching.iEntries[1].iPos);
sl@0:         }
sl@0:     }
sl@0:     
sl@0: #endif
sl@0: 
sl@0: 
sl@0: 
sl@0: