--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/userlibandfileserver/fileserver/sfat/ram_fat_table.cpp Mon Oct 19 15:55:17 2009 +0100
@@ -0,0 +1,478 @@
+// Copyright (c) 1996-2009 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:
+// f32\sfat\ram_fat_table.cpp
+// FAT16 File Allocation Table classes implementation for the RAM media
+//
+//
+
+/**
+ @file
+ @internalTechnology
+*/
+
+
+
+#include "sl_std.h"
+#include "sl_fatcache.h"
+#include "fat_table.h"
+
+
+//#######################################################################################################################################
+//# CRamFatTable class implementation
+//#######################################################################################################################################
+
+/**
+Constructor, the RamFatTable allows disk compression by redirecting the FAT
+
+@param aOwner Owning mount.
+*/
+CRamFatTable::CRamFatTable(CFatMountCB& aOwner)
+ :CFatTable(aOwner)
+ {
+ iFatTablePos=aOwner.FirstFatSector()<<aOwner.SectorSizeLog2();
+ iIndirectionTablePos=iFatTablePos+aOwner.FatSizeInBytes();
+ }
+
+/** factory method */
+CRamFatTable* CRamFatTable::NewL(CFatMountCB& aOwner)
+{
+ __PRINT1(_L("CRamFatTable::NewL() drv:%d"),aOwner.DriveNumber());
+
+ CRamFatTable* pSelf = new (ELeave) CRamFatTable(aOwner);
+
+ CleanupStack::PushL(pSelf);
+ pSelf->InitializeL();
+ CleanupStack::Pop();
+
+ return pSelf;
+}
+
+void CRamFatTable::InitializeL()
+{
+ CFatTable::InitializeL();
+
+ ASSERT(iMediaAtt & KMediaAttVariableSize);
+
+ iFatTablePos=iOwner->FirstFatSector()<<iOwner->SectorSizeLog2();
+ iIndirectionTablePos=iFatTablePos+iOwner->FatSizeInBytes();
+
+ //-- set RAM disk base
+ TLocalDriveCapsV2 caps;
+ TPckg<TLocalDriveCapsV2> capsPckg(caps);
+ User::LeaveIfError(iOwner->LocalDrive()->Caps(capsPckg));
+
+ iRamDiskBase = caps.iBaseAddress;
+}
+
+/**
+ Remount the FAT table. This method call means that the media parameters wasn't changed,
+ otherwise CFatMountCB::DoReMountL() would reject it.
+ Just do some re-initialisation work.
+*/
+void CRamFatTable::ReMountL()
+{
+ //-- re-initialise, actually
+ ASSERT(iMediaAtt & KMediaAttVariableSize);
+ ASSERT(FatType() == EFat16);
+
+ iFatTablePos=iOwner->FirstFatSector()<<iOwner->SectorSizeLog2();
+ iIndirectionTablePos=iFatTablePos+iOwner->FatSizeInBytes();
+
+ //-- set RAM disk base
+ TLocalDriveCapsV2 caps;
+ TPckg<TLocalDriveCapsV2> capsPckg(caps);
+ User::LeaveIfError(iOwner->LocalDrive()->Caps(capsPckg));
+
+ iRamDiskBase = caps.iBaseAddress;
+}
+
+
+/**
+Return the start address of the Ram Drive
+
+@return start address of the Ram Drive
+*/
+TUint8 *CRamFatTable::RamDiskBase() const
+ {
+ return(iRamDiskBase);
+ }
+
+
+/**
+Allocate a new cluster number
+
+@return New cluster number
+*/
+TInt CRamFatTable::AllocateClusterNumber()
+ {
+ return(iOwner->MaxClusterNumber()-NumberOfFreeClusters());
+ }
+
+/**
+Write a value to the FAT (indirection table)
+
+@param aFatIndex Cluster to write to
+@param aValue value to write to Fat
+@leave
+*/
+void CRamFatTable::WriteL(TUint32 aFatIndex, TUint32 aValue)
+ {
+ //__PRINT(_L("CRamFatTable::WriteL"));
+
+ __ASSERT_ALWAYS(aFatIndex>=2 && (aValue>=2 || aValue==0) && aValue<=0xFFFF,User::Leave(KErrCorrupt));
+ TUint32 indirectCluster=aFatIndex;
+ TUint32 indirectClusterNewVal=0;
+ ReadIndirectionTable(indirectCluster);
+// If value in indirection table!=0 we assume we have already written to the indirection table
+// So just update the FAT table
+ if (indirectCluster!=0 && aValue!=0)
+ {
+ WriteFatTable(aFatIndex,aValue);
+ return;
+ }
+// If value in indirection table is 0, we haven't written to it yet, though the memory has
+// already been allocated by the EnlargeL() function
+ if (indirectCluster==0 && aValue!=0) // Assumes memory has already been allocated
+ indirectClusterNewVal=AllocateClusterNumber();
+// Write aValue into aFaxIndex and indirectClusterNewVal into the corresponding position
+// in the indirection table
+ WriteFatTable(aFatIndex,aValue,indirectClusterNewVal);
+ }
+
+/**
+Read the value of a cluster in the Fat
+
+@param aFatIndex A cluster to read
+@leave
+@return The cluster value read
+*/
+
+TUint32 CRamFatTable::ReadL(TUint32 aFatIndex) const
+ {
+ __ASSERT_ALWAYS(aFatIndex>=KFatFirstSearchCluster,User::Leave(KErrCorrupt));
+ TUint clusterVal=*(TUint16*)(RamDiskBase()+PosInBytes(aFatIndex)+iFatTablePos);
+ return(clusterVal);
+ }
+
+/**
+Write a value to the FAT and indirection table
+
+@param aFatIndex Cluster number to write to
+@param aFatValue Cluster value for Fat
+@param anIndirectionValue Value for indirection table
+*/
+void CRamFatTable::WriteFatTable(TInt aFatIndex,TInt aFatValue,TInt anIndirectionValue)
+ {
+ TUint8* pos=RamDiskBase()+PosInBytes(aFatIndex);
+ *(TUint16*)(pos+iFatTablePos)=(TUint16)aFatValue;
+ *(TUint16*)(pos+iIndirectionTablePos)=(TUint16)anIndirectionValue;
+ }
+
+/**
+Write to just the fat table
+
+@param aFatIndex Cluster number to write to
+@param aFatValue Cluster value for Fat
+*/
+void CRamFatTable::WriteFatTable(TInt aFatIndex,TInt aFatValue)
+ {
+ *(TUint16*)(RamDiskBase()+PosInBytes(aFatIndex)+iFatTablePos)=(TUint16)aFatValue;
+ }
+
+/**
+Write to just the fat table
+
+@param aFatIndex Cluster number to write to
+@param aFatValue Value for indirection table
+*/
+void CRamFatTable::WriteIndirectionTable(TInt aFatIndex,TInt aFatValue)
+ {
+ *(TUint16*)(RamDiskBase()+PosInBytes(aFatIndex)+iIndirectionTablePos)=(TUint16)aFatValue;
+ }
+
+/**
+Find the real location of aCluster
+
+@param aCluster Cluster to read, contians cluster value upon return
+*/
+void CRamFatTable::ReadIndirectionTable(TUint32& aCluster) const
+ {
+ aCluster=*(TUint16*)(RamDiskBase()+PosInBytes(aCluster)+iIndirectionTablePos);
+ }
+
+/**
+Copy memory in RAM drive area, unlocking required
+
+@param aTrg Pointer to destination location
+@param aSrc Pointer to source location
+@param aLength Length of data to copy
+@return Pointer to end of data copied
+*/
+TUint8* CRamFatTable::MemCopy(TAny* aTrg,const TAny* aSrc,TInt aLength)
+ {
+ TUint8* p=Mem::Copy(aTrg,aSrc,aLength);
+ return(p);
+ }
+
+/**
+ Copy memory with filling the source buffer with zeroes. Target and source buffers can overlap.
+ Used on RAMDrive srinking in order to wipe data from the file that is being deleted.
+
+ @param aTrg pointer to the target address
+ @param aSrc pointer to the destination address
+ @param aLength how many bytes to copy
+ @return A pointer to a location aLength bytes beyond aTrg (i.e. the location aTrg+aLength).
+*/
+TUint8* CRamFatTable::MemCopyFillZ(TAny* aTrg, TAny* aSrc,TInt aLength)
+{
+ //-- just copy src to the trg, the memory areas can overlap.
+ TUint8* p=Mem::Copy(aTrg, aSrc, aLength);
+
+ //-- now zero-fill the source memory area taking into account possible overlap.
+ TUint8* pSrc = static_cast<TUint8*>(aSrc);
+ TUint8* pTrg = static_cast<TUint8*>(aTrg);
+
+ TUint8* pZFill = NULL; //-- pointer to the beginning of zerofilled area
+ TInt zFillLen = 0; //-- a number of bytes to zero-fill
+
+ if(aTrg < aSrc)
+ {
+ if(pTrg+aLength < pSrc)
+ {//-- target and source areas do not overlap
+ pZFill = pSrc;
+ zFillLen = aLength;
+ }
+ else
+ {//-- target and source areas overlap, try not to corrupt the target area
+ zFillLen = pSrc-pTrg;
+ pZFill = pTrg+aLength;
+ }
+ }
+ else
+ {
+ if(pSrc+aLength < pTrg)
+ {//-- target and source areas do not overlap
+ pZFill = pSrc;
+ zFillLen = aLength;
+ }
+ else
+ {//-- target and source areas overlap, try not to corrupt the target area
+ zFillLen = pSrc+aLength-pTrg;
+ pZFill = pSrc;
+ }
+ }
+
+ Mem::FillZ(pZFill, zFillLen);
+
+ return(p);
+}
+
+/**
+ Zero fill RAM area corresponding to the cluster number aCluster
+ @param aCluster a cluster number to be zero-filled
+*/
+void CRamFatTable::ZeroFillCluster(TInt aCluster)
+{
+ TLinAddr clusterPos= I64LOW(DataPositionInBytes(aCluster));
+ Mem::FillZ(iRamDiskBase+clusterPos, 1<< iOwner->ClusterSizeLog2());
+ }
+
+
+/**
+Return the location of a Cluster in the data section of the media
+
+@param aCluster to find location of
+@return Byte offset of the cluster data
+*/
+TInt64 CRamFatTable::DataPositionInBytes(TUint32 aCluster) const
+ {
+ //__PRINT(_L("CRamFatTable::DataPositionInBytes"));
+ ReadIndirectionTable(aCluster);
+ return(aCluster<<iOwner->ClusterSizeLog2());
+ }
+
+/**
+Allocate and mark as EOF a single cluster as close as possible to aNearestCluster,
+calls base class implementation but must Enlarge the RAM drive first. Allocated cluster RAM area will be zero-filled.
+
+@param aNearestCluster Cluster the new cluster should be nearest to
+@leave System wide error codes
+@return The cluster number allocated
+*/
+TUint32 CRamFatTable::AllocateSingleClusterL(TUint32 aNearestCluster)
+ {
+ __PRINT(_L("CRamFatTable::AllocateSingleClusterL"));
+ iOwner->EnlargeL(1<<iOwner->ClusterSizeLog2()); // First enlarge the RAM drive
+ TInt fileAllocated=CFatTable::AllocateSingleClusterL(aNearestCluster); // Now update the free cluster and fat/fit
+ ZeroFillCluster(fileAllocated); //-- zero-fill allocated cluster
+ return(fileAllocated);
+ }
+
+
+/**
+ Extend a file or directory cluster chain, enlarging RAM drive first. Allocated clusters are zero-filled.
+ Leaves if there are no free clusters (the disk is full).
+ Note that method now doesn't call CFatTable::ExtendClusterListL() from its base class, be careful making changes there.
+
+ @param aNumber number of clusters to allocate
+ @param aCluster starting cluster number / ending cluster number after
+ @leave KErrDiskFull + system wide error codes
+*/
+void CRamFatTable::ExtendClusterListL(TUint32 aNumber,TInt& aCluster)
+ {
+ __PRINT(_L("CRamFatTable::ExtendClusterListL"));
+ __ASSERT_DEBUG(aNumber>0,Fault(EFatBadParameter));
+
+ iOwner->EnlargeL(aNumber<<iOwner->ClusterSizeLog2());
+
+ while(aNumber && GetNextClusterL(aCluster))
+ aNumber--;
+
+ if(!aNumber)
+ return;
+
+ if (NumberOfFreeClusters() < aNumber)
+ {
+ __PRINT(_L("CRamFatTable::ExtendClusterListL - leaving KErrDirFull"));
+ User::Leave(KErrDiskFull);
+ }
+
+ while (aNumber--)
+ {
+ const TInt freeCluster=FindClosestFreeClusterL(aCluster);
+
+ WriteFatEntryEofL(freeCluster); // Must write EOF for FindClosestFreeCluster to work again
+ DecrementFreeClusterCount(1);
+ WriteL(aCluster,freeCluster);
+ aCluster=freeCluster;
+ ZeroFillCluster(freeCluster); //-- zero fill just allocated cluster (RAM area)
+ }
+
+ SetFreeClusterHint(aCluster);
+
+ }
+
+/**
+Mark a chain of clusters as free in the FAT. Shrinks the RAM drive once the
+clusters are free
+
+@param aCluster Start cluster of cluster chain to free
+@leave System wide error codes
+*/
+void CRamFatTable::FreeClusterListL(TUint32 aCluster)
+ {
+ __PRINT1(_L("CRamFatTable::FreeClusterListL aCluster=%d"),aCluster);
+ if (aCluster==0)
+ return; // File has no cluster allocated
+
+ const TInt clusterShift=iOwner->ClusterSizeLog2();
+ TInt startCluster=aCluster;
+ TInt endCluster=0;
+ TInt totalFreed=0;
+ TLinAddr srcEnd=0;
+
+ while(endCluster!=EOF_16Bit)
+ {
+ TInt num=CountContiguousClustersL(startCluster,endCluster,KMaxTInt);
+ if (GetNextClusterL(endCluster)==EFalse || endCluster==0)
+ endCluster=EOF_16Bit; // endCluster==0 -> file contained FAT loop
+
+ // Real position in bytes of the start cluster in the data area
+ TLinAddr startClusterPos= I64LOW(DataPositionInBytes(startCluster));
+ // Sliding value when more than one block is freed
+ TLinAddr trg=startClusterPos-(totalFreed<<clusterShift);
+ __PRINT1(_L("trg=0x%x"),trg);
+
+ // Beginning of data area to move
+ TLinAddr srcStart=startClusterPos+(num<<clusterShift);
+ __PRINT1(_L("srcStart=0x%x"),srcStart);
+ // Position of next part of cluster chain or position of end of ram drive
+ if (endCluster==EOF_16Bit) // Last cluster is the end of the chain
+ {
+
+
+ // Fixed to use the genuine RAM drive size rather than the number
+ // of free clusters - though they *should* be the same
+ // It avoids the problem of iFreeClusters getting out of sync with
+ // the RAM drive size but doesn't solve the issue of why it can happen...
+
+ srcEnd=I64LOW(iOwner->Size());
+ __PRINT1(_L("srcEnd=0x%x"),srcEnd);
+ }
+ else // Just move up to the next part of the chain
+ srcEnd=I64LOW(DataPositionInBytes(endCluster));
+
+ //-- Copy (srcEnd-srcStart) bytes from iRamDiskBase+srcStart onto iRamDiskBase+trg
+ //-- zero-filling free space to avoid leaving something important there
+ ASSERT(srcEnd >= srcStart);
+ if(srcEnd-srcStart > 0)
+ {
+ MemCopyFillZ(iRamDiskBase+trg,iRamDiskBase+srcStart,srcEnd-srcStart);
+ }
+ else
+ {//-- we are freeing the cluster chain at the end of the RAMdrive; Nothing to copy to the drive space that has become free,
+ //-- but nevertheless zero fill this space.
+ Mem::FillZ(iRamDiskBase+trg, num<<clusterShift);
+ }
+
+ totalFreed+=num;
+ startCluster=endCluster;
+ UpdateIndirectionTable(srcStart>>clusterShift,srcEnd>>clusterShift,totalFreed);
+ }
+ TInt bytesFreed=totalFreed<<clusterShift;
+
+// First free the cluster list
+ CFatTable::FreeClusterListL(aCluster);
+// Now reduce the size of the RAM drive
+ iOwner->ReduceSizeL(srcEnd-bytesFreed,bytesFreed);
+ }
+
+/**
+Shift any clusters between aStart and anEnd backwards by aClusterShift
+
+@param aStart Start of shift region
+@param anEnd End of shift region
+@param aClusterShift amount to shift cluster by
+*/
+void CRamFatTable::UpdateIndirectionTable(TUint32 aStart,TUint32 anEnd,TInt aClusterShift)
+ {
+ __PRINT(_L("CRamFatTable::UpdateIndirectionTable"));
+#if defined(__WINS__)
+ TUint32 count=iOwner->MaxClusterNumber();
+ while (count--)
+ {
+ TUint32 cluster=count;
+ ReadIndirectionTable(cluster);
+ if (cluster>=aStart && cluster<anEnd)
+ WriteIndirectionTable(count,cluster-aClusterShift);
+ }
+#else
+ TUint16* table=(TUint16*)(RamDiskBase()+iIndirectionTablePos);
+ TUint16* entry=table+iOwner->MaxClusterNumber();
+ while (entry>table)
+ {
+ TUint32 cluster=*--entry;
+ if (cluster<aStart)
+ continue;
+ if (cluster<anEnd)
+ *entry=TUint16(cluster-aClusterShift);
+ }
+#endif
+ }
+
+
+
+
+
+