--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/persistentstorage/store/USTOR/UT_PERM.CPP	Fri Jan 22 11:06:30 2010 +0200
@@ -0,0 +1,1441 @@
+// Copyright (c) 1998-2009 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 <s32file.h>
+#include "UT_STD.H"
+
+//The default media block size, used in the computations, if the file system guarantees atomic "block write" file operations.
+const TInt KDefaultMediaBlockSize = 512;
+
+////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+/////////////////////              TPermanentStoreHeader               /////////////////////////////////////////////////////
+////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+//Returns false, if:
+// - the dirty bit is set (indicates commit phase #2 or #3 is not complete);
+// - the CRC check fails ("backup TOC ref", "handle" and "TOC ref" are protected by 16-bit CRC in the permanent store file header);
+TBool TPermanentStoreHeader::IsValid() const
+	{
+	if (IsDirty())
+		return EFalse;
+//
+	TUint16 crc=0;
+	Mem::Crc(crc,Ptr(),_FOFF(TPermanentStoreHeader,iCrc));
+	return crc==iCrc;
+	}
+
+//Sets the "backup TOC ref", "handle" and "TOC ref" in current TPermanentStoreHeader object.
+//16-bit CRC is calculated, based on the values of the input parameters, and stored together with them in the 
+//TPermanentStoreHeader object.
+void TPermanentStoreHeader::Set(TInt aBackupToc,TInt aHandle,TInt aReference)
+	{
+	iBackup=TUint32(aBackupToc)<<1;
+	iHandle=aHandle;
+	iRef=aReference;
+	iCrc=0;
+	Mem::Crc(iCrc,Ptr(),_FOFF(TPermanentStoreHeader,iCrc));
+	__ASSERT_DEBUG(IsValid(),User::Invariant());
+	}
+
+const TInt KTocGranularity=12;
+
+struct STocEntry
+	{
+	TInt32 handle;
+	TInt32 ref;
+	};
+
+////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+/////////////////////              CPermanentStoreToc               ////////////////////////////////////////////////////////
+////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+TInt CPermanentStoreToc::TEntry::Compare(const TEntry& aLeft, const TEntry& aRight)
+//
+// Ordering for Stream handles, return <0,0,>0 depending on comparison
+// The index part of the handle is only 24 bits, so just subtract the handles for result
+//
+	{
+	return (aLeft.handle&KMaskHandleIndex) - (aRight.handle&KMaskHandleIndex);
+	}
+
+CPermanentStoreToc* CPermanentStoreToc::NewL(TStreamPos aBase,TStreamExchange& aHost,TInt aToc,TInt aBaseReloc)
+	{
+	CPermanentStoreToc* table=new(ELeave) CPermanentStoreToc(aBase,aHost);
+	CleanupStack::PushL(table);
+	table->ConstructL(aToc,aBaseReloc);
+	CleanupStack::Pop();
+	return table;
+	}
+
+TBool CPermanentStoreToc::IsDelta() const
+//
+// Report whether the current TOC should be written as a delta, or a base TOC
+//
+	{
+	TInt delta = iEntries.Count();
+	if (delta >= KTocDeltaCap)
+		return EFalse;
+	TInt magic = iMagic + delta;
+	if (magic > KMaxTocDeltaMagic)
+		return EFalse;
+	return magic*KSizeTocDeltaEntry <= iCount*KSizeTocEntry - KSizeTocDeltaExtra;
+	}
+
+void CPermanentStoreToc::Move(TInt aToc,TInt anExtent)
+//
+// Final stage of compaction, update to address new TOC
+//
+	{
+	__ASSERT_DEBUG(anExtent<=iOff&&anExtent>=aToc&&anExtent-(aToc+KOffsetTocHeader)==iExt-iOff,User::Invariant());
+	if (!HasDelta())
+		{
+		// Base-toc only, update the base toc position as well
+		TInt window=iWindow-iTocExt;
+		iTocOff=aToc+KOffsetTocHeader;
+		iTocExt=anExtent;
+		iWindow=anExtent+window;
+		}
+	iOff = aToc+KOffsetTocHeader;
+	iExt = anExtent;
+	}
+
+TInt CPermanentStoreToc::RealizeL(TInt aPrimary,TInt anExtent) const
+	{
+	__ASSERT_DEBUG(IsVirtual(),User::Invariant());
+	RFrame16Buf buf(Base());
+	buf.PushL();
+	const TBool delta = IsDelta();
+	aPrimary &= KMaskStreamIdValue;
+	if (delta)
+		aPrimary |= KTocDelta;
+	STocHead h;
+	h.primary=TInt32(aPrimary);
+	h.avail=TInt32(iAvail);
+	h.count=TUint32(iCount);
+//
+	TInt off;
+	if (delta)
+		off=DeltaL(buf,anExtent,h);
+	else
+		off=RewriteL(buf,anExtent,h);
+//
+	buf.SynchL();
+	CleanupStack::PopAndDestroy(&buf);
+	return off-KOffsetTocHeader;
+	}
+
+void CPermanentStoreToc::Adopt(TInt aToc,TInt aPrimary)
+//
+// Final stage of Commit - all file changes have been successful
+// Record the new Toc location and reset the changed flag
+//
+	{
+	__ASSERT_DEBUG(aToc+KOffsetTocHeader>=iExt,User::Invariant());
+
+	if (IsDelta())
+		{
+		// Adjust the TOC-delta location
+		TInt c = iEntries.Count();
+		iOff=aToc+KOffsetTocHeader;
+		iExt=aToc + KSizeTocDeltaExtra + KSizeTocDeltaEntry*c;
+		if (c > KTocDeltaMagic)
+			iMagic += c - KTocDeltaMagic;
+		}
+	else
+		{
+		// Adjust all the TOC data and reset the delta-set
+		TInt window = iTocOff>=0 ? iWindow-iTocOff : -KOffsetTocHeader;
+		iTocOff=iOff=aToc+KOffsetTocHeader;
+		iTocExt=iExt=aToc+KSizeTocEntry*iCount;
+		iWindow = iTocOff + window;
+		iEntries.Reset();
+		iMagic = 0;
+		}
+	iPrimary=aPrimary;
+	__ASSERT_DEBUG(!IsVirtual(),User::Invariant());
+	}
+
+TInt CPermanentStoreToc::AllocL(TInt anOffset)
+	{
+	TEntry& entry=DoAllocL();
+	entry.ref=anOffset;
+	return entry.handle;
+	}
+
+TInt CPermanentStoreToc::AllocL()
+	{
+	TEntry& entry=DoAllocL();
+	entry.ref=KFrameNonexistent16;
+	return entry.handle|=KHandleInvalid;
+	}
+
+void CPermanentStoreToc::Cancel(TInt aHandle)
+	{
+	__ASSERT_DEBUG(aHandle<0&&IsVirtual(),User::Invariant());
+	TEntry* entry=Entry(aHandle);
+	__ASSERT_DEBUG((entry!=NULL) && (entry->handle==aHandle),User::Invariant());
+	entry->ref=iAvail;
+	iAvail=aHandle;
+	}
+
+void CPermanentStoreToc::FreeL(TInt aHandle)
+	{
+	__ASSERT_DEBUG(aHandle>0,User::Invariant());
+	TEntry& entry=FetchL(aHandle);
+	aHandle|=KHandleInvalid;
+	entry.handle=aHandle;
+	entry.ref=iAvail;
+	iAvail=aHandle;
+	Changed();
+	}
+
+TInt CPermanentStoreToc::AtL(TInt aHandle) const
+	{
+	__ASSERT_DEBUG(aHandle>0,User::Invariant());
+
+	// check the delta table
+	const TEntry* entry=Entry(aHandle);
+	if (entry!=NULL )
+		{
+		// if there is an entry in the delta table, but its
+		// not an exact match leave with KErrNotFound
+		// This happens when the delta indicates it's been deleted
+		if (entry->handle!=aHandle)
+			User::Leave(KErrNotFound);
+		
+		return entry->ref;
+		}
+//
+	// if it's not in the delta table check the base TOC
+	return DoAtL(aHandle);
+	}
+
+void CPermanentStoreToc::PutL(TInt aHandle, TInt anOffset, TPut aCheck)
+//
+// Used by compaction to update a single stream reference IN-PLACE in the TOC
+// We need to check in which TOC to make the update
+//
+	{
+	__ASSERT_DEBUG(!IsVirtual(),User::Invariant());
+	__ASSERT_DEBUG(aHandle>0,User::Invariant());
+	__ASSERT_DEBUG(aHandle!=KHandleTocBase || HasDelta(),User::Invariant());
+
+	if (aHandle == KHandleTocBase)
+		{
+		// update the TOC-base link
+		PutTocL(anOffset - KOffsetTocHeader, aCheck);
+		if (iTocOff != anOffset)
+			{
+			TInt size = iTocExt - iTocOff;
+			TInt window = iWindow - iTocOff;
+			iTocOff = anOffset;
+			iTocExt = anOffset + size;
+			iWindow = anOffset + window;
+			}
+		return;
+		}
+
+	TEntry e;
+	e.handle=aHandle;
+	TInt i;
+	if (iEntries.FindInOrder(e,i,&TEntry::Compare)==0)
+		{
+		// update TOC-delta entry
+		TEntry& entry=iEntries[i];
+		if (entry.handle==aHandle && entry.ref != anOffset)
+			{
+			PutDeltaL(i,aHandle,anOffset);
+			entry.ref=anOffset;
+			}
+		return;
+		}
+
+	// update TOC-base entry
+	if (aCheck==EWrite || DoAtL(aHandle)!=anOffset)
+		PutBaseL(aHandle,anOffset);
+	}
+
+TInt CPermanentStoreToc::GetL(TInt aHandle)
+	{
+	__ASSERT_DEBUG(aHandle>0,User::Invariant());
+	TEntry& entry=FetchL(aHandle);
+	return entry.ref;
+	}
+
+TInt CPermanentStoreToc::Set(TInt aHandle,TInt anOffset)
+	{
+	__ASSERT_DEBUG(aHandle!=0,User::Invariant());
+	TEntry* entry=Entry(aHandle);
+	__ASSERT_DEBUG((entry!=NULL) && (entry->handle==aHandle),User::Invariant());
+	aHandle&=KMaskStreamIdValue;
+	entry->handle=aHandle;
+	entry->ref=anOffset;
+	Changed();
+	return aHandle;
+	}
+
+CPermanentStoreToc::CPermanentStoreToc(TStreamPos aBase,TStreamExchange& aHost)
+	: /*iPrimary(0),iAvail(0),iCount(0),*/iEntries(KTocGranularity),
+		iBase(aBase),iHost(&aHost),iOff(KFrameNonexistent16)/*,iExt(0)*/,
+		iTocOff(KFrameNonexistent16)/*,iTocExt(0),iWindow(0)*/
+	{}
+
+CPermanentStoreToc::~CPermanentStoreToc()
+	{
+	iEntries.Close();
+	}
+
+void CPermanentStoreToc::ConstructL(TInt aToc,TInt aBaseReloc)
+//
+// Read and validate the TOC header at aToc.
+// aBaseReloc may contain a relocated TOC-base offset, which should override the one in a TOC-delta
+//
+	{
+	if (aToc==0)
+		return;
+	__ASSERT_DEBUG(aToc>0&&iEntries.Count()==0,User::Invariant());
+	RFrame16Buf buf(Base());
+	aToc+=KOffsetTocHeader;
+	buf.OpenL(Host(),aToc,EFrameDescriptive16|buf.ERead);
+	buf.PushL();
+	RReadStream stream(&buf);
+	STocHead h;
+	stream.ReadL((TUint8*)&h,sizeof(STocHead)); // platform dependency
+	if ((h.primary&~(KMaskStreamIdValue|static_cast<TUint>(KTocDelta)))!=0||
+		h.avail>0||(h.avail&KMaskHandleClear)!=0||(h.count&~KMaskHandleIndex)!=0)
+		__LEAVE(KErrCorrupt);
+//
+	iPrimary=TInt(h.primary) & ~KTocDelta;
+	iAvail=TInt(h.avail);
+	iCount=TInt(h.count);
+	iOff = aToc;
+//
+	if (h.primary & KTocDelta)
+		{
+		// This is a TOC-delta
+		aToc = InternalizeL(stream, aBaseReloc) + KOffsetTocHeader;
+
+		// Now locate and validate the base TOC
+		buf.Release();
+		buf.OpenL(Host(),aToc,EFrameDescriptive16|buf.ERead);
+		stream.ReadL((TUint8*)&h,sizeof(STocHead)); // platform dependency
+		if ((h.primary&~KMaskStreamIdValue)!=0||(h.count&~KMaskHandleIndex)!=0||
+			h.avail>0||(h.avail&KMaskHandleClear)!=0||TInt(h.count)>iCount)
+			__LEAVE(KErrCorrupt);
+		}
+	TInt size = KSizeTocEntry*TInt(h.count);
+// Eagerly load the first few TOC entries into the cache
+// This is good as it almost certainly lies in the file buffer already
+	if (size>0)
+		stream.ReadL(&iBuf[0],Min(size,TInt(KSizeTocBuf)));
+	size-=KOffsetTocHeader;
+	if (buf.SizeL()!=size)
+		__LEAVE(KErrCorrupt);
+	iTocOff=aToc;
+	iWindow=aToc-KOffsetTocHeader;
+	iTocExt=aToc+size;
+	if (iExt == 0)
+		iExt = iTocExt;		// set extent for non-delta TOC
+//
+	CleanupStack::PopAndDestroy(&buf);
+	}
+
+TInt CPermanentStoreToc::InternalizeL(RReadStream& aIn, TInt aBaseReloc)
+//
+// Load and validate the delta-toc table
+//
+	{
+	TInt tocoff = aIn.ReadInt32L();
+	if (aBaseReloc != KFrameNonexistent16)
+		tocoff = aBaseReloc - KOffsetTocHeader;
+	if (tocoff<0||tocoff>=iOff)
+		__LEAVE(KErrCorrupt);
+	iMagic = aIn.ReadUint16L();
+	if (!IsDelta())
+		__LEAVE(KErrCorrupt);
+	TInt n = aIn.ReadUint8L();
+	TInt size = -KOffsetTocHeader + KSizeTocDeltaExtra + KSizeTocDeltaEntry * n;
+	if (aIn.Source()->SizeL()!=size)
+		__LEAVE(KErrCorrupt);
+	iExt = iOff + size;
+	TInt last = 0;
+	while (--n >= 0)
+		{
+		STocEntry e;
+		aIn.ReadL((TUint8*)&e,KSizeTocDeltaEntry);	// platform dependency
+		if ((e.handle&KMaskHandleClear)!=0||e.handle>=0&&(e.ref<KFrameNonexistent16)||
+			e.handle<0&&(e.ref>0||(e.ref&KMaskHandleClear)!=0))
+			__LEAVE(KErrCorrupt);
+		TInt i = e.handle&KMaskHandleIndex;
+		if (i <= last || i > iCount)
+			__LEAVE(KErrCorrupt);
+		last = i;
+		TEntry entry;
+		entry.handle = TInt(e.handle);
+		entry.ref = TInt(e.ref);
+		User::LeaveIfError(iEntries.Append(entry));
+		}
+
+	return tocoff;
+	}
+
+TInt CPermanentStoreToc::DeltaL(RFrame16Buf& aBuf,TInt aExtent,const STocHead& aHead) const
+//
+// Write the TOC-delta
+//
+	{
+	TInt off=aBuf.ExtendL(Host(),aExtent,EFrameDescriptive16|aBuf.EWrite);
+	RWriteStream out(&aBuf);
+	out.WriteL((TUint8*)&aHead,sizeof(STocHead)); // platform dependency
+	out.WriteInt32L(iTocOff - KOffsetTocHeader);
+	TInt n = iEntries.Count();
+	TInt magic = iMagic;
+	if (n > KTocDeltaMagic)
+		magic += n - KTocDeltaMagic;
+	__ASSERT_DEBUG(magic <= KMaxTocDeltaMagic,User::Invariant());
+	__ASSERT_DEBUG(n <= (TInt)KMaxTUint8, User::Invariant());
+	out.WriteUint16L(magic);
+	out.WriteUint8L(n);
+	for (int i = 0; i < n; ++i)
+		{
+		const TEntry& entry = iEntries[i];
+		STocEntry e;
+		e.handle=TInt32(entry.handle);
+		e.ref=TInt32(entry.ref);
+		out.WriteL((TUint8*)&e,KSizeTocDeltaEntry); // platform dependency
+		}
+	return off;
+	}
+
+TInt CPermanentStoreToc::RewriteL(RFrame16Buf& aBuf,TInt aExtent,const STocHead& aHead) const
+//
+// Write the TOC-base
+//
+	{
+	const TInt KElementsRewrite=304;
+	const TInt KSizeRewriteBuf=KElementsRewrite*KSizeTocEntry;
+	TUint8 toc[KSizeRewriteBuf];
+
+	RFrame16Buf buf(Base());
+	buf.PushL();
+	TInt oldsize = 0;
+	TInt window = 0;
+	if (iTocOff>=0)
+		{
+		oldsize = iTocExt-iTocOff+KOffsetTocHeader;
+		window = iWindow + KOffsetTocHeader - iTocOff;
+		if (oldsize <= Min(KSizeTocBuf,KSizeRewriteBuf) && window == 0)
+			{
+			// the old TOC is already in the toc-base cache, no need to read it
+			Mem::Copy(&toc[0],&iBuf[0],oldsize);
+			oldsize = 0;	// this prevents the read request
+			}
+		else
+			{
+			buf.Set(Host(),iTocOff,iTocExt,EFrameDescriptive16|buf.ERead);
+			buf.SeekL(buf.ERead,TStreamPos(-KOffsetTocHeader));
+			}
+		}
+	RReadStream in(&buf);
+	// defer the initialisation of the write in roder to improve file buffering performance
+	RWriteStream out(&aBuf);
+	TInt off=-1;
+	TInt size=iCount*KSizeTocEntry;
+
+	for (TInt base=0,delta=0;base<size;base+=KSizeRewriteBuf)
+		{
+		// fill buffer with old TOC data
+		if (base < oldsize)
+			in.ReadL(&toc[0],Min(KSizeRewriteBuf,oldsize-base));
+		// apply changes to this block
+		for (TInt n=iEntries.Count();delta<n;++delta)
+			{
+			const TEntry& entry=iEntries[delta];
+			TInt pos = (entry.handle&KMaskHandleIndex)*KSizeTocEntry - KSizeTocEntry - base;
+			__ASSERT_DEBUG(pos>=0,User::Invariant());
+			if (pos>=KSizeRewriteBuf)
+				break;
+			STocEntry e;
+			e.handle=TInt32(entry.handle);
+			e.ref=TInt32(entry.ref);
+			Mem::Copy(&toc[pos],(const TUint8*)&e+KSizeHandleIndex,KSizeTocEntry);
+			pos += base - window;
+			if (TUint(pos) < TUint(KSizeTocBuf))
+				Mem::Copy(MUTABLE_CAST(TUint8*,&iBuf[pos]),(const TUint8*)&e+KSizeHandleIndex,KSizeTocEntry);
+			}
+		// write buffer to file
+		if (off == -1)
+			{
+			// initialise writing
+			off=aBuf.ExtendL(Host(),aExtent,EFrameDescriptive16|aBuf.EWrite);
+			out.WriteL((TUint8*)&aHead,sizeof(STocHead)); // platform dependency
+			}
+		out.WriteL(&toc[0],Min(KSizeRewriteBuf,size-base));
+		}
+//
+	CleanupStack::PopAndDestroy(&buf);
+	return off;
+	}
+
+CPermanentStoreToc::TEntry* CPermanentStoreToc::Entry(TInt aHandle)
+	{
+	TEntry e;
+	e.handle=aHandle;
+	TInt i;
+	if (iEntries.FindInOrder(e,i,&TEntry::Compare)!=0)
+		return NULL;
+//
+	TEntry& entry=iEntries[i];
+	
+	// allow entry to return a pointer even if not an exact match
+	return &entry;
+	}
+
+CPermanentStoreToc::TEntry& CPermanentStoreToc::FetchL(TInt aHandle)
+	{
+	TEntry e;
+	e.handle=aHandle;
+	TInt i;
+	if (iEntries.FindInOrder(e,i,&TEntry::Compare)!=0)
+		{
+		e.ref=DoAtL(aHandle);
+		User::LeaveIfError(iEntries.Insert(e,i));
+		}
+	TEntry& entry=iEntries[i];
+	if (entry.handle!=aHandle)
+		__LEAVE(KErrNotFound);
+//
+	return entry;
+	}
+
+CPermanentStoreToc::TEntry& CPermanentStoreToc::DoAllocL()
+	{
+	TInt handle=iAvail;
+	TEntry* entry;
+	if (handle==0)
+		{
+		__ASSERT_DEBUG(iEntries.Count()==0||(iEntries[iEntries.Count()-1].handle&KMaskHandleIndex)<=iCount,User::Invariant());
+		User::LeaveIfError(iEntries.Append(TEntry()));
+		entry=&iEntries[iEntries.Count()-1];
+		handle=++iCount;
+		}
+	else
+		{
+		entry=&FetchL(handle);
+		handle=(handle+KIncHandleGen)&KMaskStreamIdValue;
+//
+		TInt avail=entry->ref;
+		if (avail>0||(avail&KMaskHandleClear)!=0)
+			__LEAVE(KErrCorrupt);
+//
+		iAvail=avail;
+		}
+	entry->handle=handle;
+	Changed();
+	return *entry;
+	}
+
+TInt CPermanentStoreToc::DoAtL(TInt aHandle) const
+	{
+	TInt off=iTocOff;
+	if (off<0)
+		__LEAVE(KErrNotFound);
+//
+	off+=-KOffsetTocHeader-KSizeTocEntry+KSizeTocEntry*(aHandle&KMaskHandleIndex);
+	__ASSERT_DEBUG(off>=iTocOff-KOffsetTocHeader,User::Invariant());
+	if (off>=iTocExt)
+		__LEAVE(KErrNotFound);
+//
+	TInt window=iWindow;
+	if (off-window<0||off-window>=KSizeTocBuf)
+		{
+		TInt len=iTocOff-KOffsetTocHeader;
+		window=Max(len,Min(off-KBackTocBuf,iTocExt-KSizeTocBuf));
+		len=Min(iTocExt-len,TInt(KSizeTocBuf));
+//
+		RFrame16Buf buf(Base());
+		buf.Set(Host(),iTocOff,iTocExt,EFrameDescriptive16|buf.ERead);
+		buf.PushL();
+		buf.SeekL(buf.ERead,TStreamPos(window-iTocOff));
+		RReadStream stream(&buf);
+		MUTABLE_CAST(TInt&,iWindow)=iTocExt;
+		stream.ReadL(MUTABLE_CAST(TUint8*,&iBuf[0]),1); // assume half decent read-ahead buffering
+		stream.ReadL(MUTABLE_CAST(TUint8*,&iBuf[1]),len-1);
+		MUTABLE_CAST(TInt&,iWindow)=window;
+		CleanupStack::PopAndDestroy();
+		}
+	STocEntry e;
+	e.handle=aHandle;
+	Mem::Copy((TUint8*)&e+KSizeHandleIndex,&iBuf[off-window],KSizeTocEntry); // platform dependency
+	if ((e.handle&KMaskHandleClear)!=0||e.handle>=0&&(e.ref<KFrameNonexistent16)||
+		e.handle<0&&(e.ref>0||(e.ref&KMaskHandleClear)!=0))
+		__LEAVE(KErrCorrupt);
+//
+	if (TInt(e.handle)!=aHandle)
+		__LEAVE(KErrNotFound);
+//
+	return TInt(e.ref);
+	}
+
+void CPermanentStoreToc::PutBaseL(TInt aHandle,TInt aReference)
+//
+// Update a TOC-base entry
+//
+	{
+	__ASSERT_DEBUG(iTocOff>=0,User::Invariant());
+
+	TInt pos=-KOffsetTocHeader-KSizeTocEntry+KSizeTocEntry*(aHandle&KMaskHandleIndex);
+	RFrame16Buf buf(Base());
+	buf.Set(Host(),iTocOff,iTocExt,EFrameDescriptive16|buf.EWrite);
+	buf.PushL();
+	buf.SeekL(buf.EWrite,TStreamPos(pos));
+	RWriteStream stream(&buf);
+	STocEntry e;
+	e.handle=aHandle;
+	e.ref=aReference;
+	stream.WriteL((TUint8*)&e+KSizeHandleIndex,KSizeTocEntry); // platform dependency
+	CleanupStack::PopAndDestroy();
+	TInt off=pos+iTocOff-iWindow;
+	if (off>=0&&off<KSizeTocBuf)
+		Mem::Copy(&iBuf[off],(const TUint8*)&e+KSizeHandleIndex,KSizeTocEntry); // platform dependency
+	}
+
+void CPermanentStoreToc::PutDeltaL(TInt aPos, TInt aHandle, TInt aReference)
+//
+// Update a single stream reference IN-PLACE in the TOC-delta
+//
+	{
+	__ASSERT_DEBUG(HasDelta(),User::Invariant());
+	__ASSERT_DEBUG(iOff>=0,User::Invariant());
+	RFrame16Buf buf(Base());
+	buf.Set(Host(),iOff,iExt,EFrameDescriptive16|buf.EWrite);
+	buf.PushL();
+	buf.SeekL(buf.EWrite,TStreamPos(-KOffsetTocHeader + KSizeTocDeltaExtra + KSizeTocDeltaEntry*aPos));
+	RWriteStream stream(&buf);
+	STocEntry e;
+	e.handle=aHandle;
+	e.ref=aReference;
+	stream.WriteL((TUint8*)&e,KSizeTocDeltaEntry); // platform dependency
+	CleanupStack::PopAndDestroy();
+	}
+
+void CPermanentStoreToc::PutTocL(TInt aTocBase, TPut aCheck)
+//
+// Update the base TOC link in the TOC-delta
+//
+	{
+	__ASSERT_DEBUG(HasDelta(),User::Invariant());
+	__ASSERT_DEBUG(iOff>=0,User::Invariant());
+	RFrame16Buf buf(Base());
+	buf.Set(Host(),iOff,iExt,EFrameDescriptive16|buf.EWrite|buf.ERead);
+	buf.PushL();
+	buf.SeekL(buf.EWrite|buf.ERead,TStreamPos(-KOffsetTocHeader));
+	RReadStream in(&buf);
+	if (aCheck==EWrite || in.ReadInt32L() != aTocBase)
+		{
+		RWriteStream out(&buf);
+		out.WriteInt32L(aTocBase);
+		}
+	CleanupStack::PopAndDestroy();
+	}
+
+// Used prior to PutL to determine exactly where in the file the TOC update will be written.
+// This may be used to eliminate the pre-put write of the relocation information in the file
+// header in situations where the write is entirely within an atomic file block.
+//
+// The detailed numbers used to offset into the TOCs are dependant on the TOC formats, as
+// implicated by other members of this class
+TInt CPermanentStoreToc::RefSpan(TInt aHandle,TInt& aLength)
+    {
+    __ASSERT_DEBUG(!IsVirtual(),User::Invariant());
+    __ASSERT_DEBUG(aHandle>0,User::Invariant());
+
+    if (aHandle == KHandleTocBase)
+        {    // locate the TOC-base link
+        __ASSERT_DEBUG(HasDelta(),User::Invariant());
+        __ASSERT_DEBUG(iOff>=0,User::Invariant());
+        aLength = sizeof(TInt32);
+        return RFrame16Buf::Position(Base(), iOff - KOffsetTocHeader).Offset();
+        }
+
+    TEntry e;
+    e.handle=aHandle;
+    TInt ix;
+    if (iEntries.FindInOrder(e, ix, &TEntry::Compare) == 0)
+        {    // locate TOC-delta entry
+        TEntry& entry=iEntries[ix];
+        if (entry.handle==aHandle)
+            {
+            __ASSERT_DEBUG(HasDelta(),User::Invariant());
+            __ASSERT_DEBUG(iOff>=0,User::Invariant());
+            aLength = KSizeTocDeltaEntry;
+            return RFrame16Buf::Position(Base(),iOff - KOffsetTocHeader + KSizeTocDeltaExtra + KSizeTocDeltaEntry*ix).Offset();
+            }
+        }
+
+    // locate the TOC-base entry
+    __ASSERT_DEBUG(iTocOff>=0,User::Invariant());
+    aLength = KSizeTocEntry;
+    return RFrame16Buf::Position(Base(),iTocOff-KOffsetTocHeader-KSizeTocEntry+KSizeTocEntry*(aHandle&KMaskHandleIndex)).Offset();
+    }
+
+////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+/////////////////////              RPermanentStoreTocIter               ////////////////////////////////////////////////////
+////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+RPermanentStoreTocIter::RPermanentStoreTocIter(const CPermanentStoreToc& aTable)
+	: iTable(aTable), iBuf(aTable.Base()), iDelta(0), iDeltaEnd(0)
+	{
+	TInt off=aTable.iTocOff;
+	__ASSERT_DEBUG(off>=KFrameNonexistent16,User::Invariant());
+	TInt ext=off<0?off:aTable.iTocExt;
+	iBuf.Set(aTable.Host(),off,ext,EFrameDescriptive16|iBuf.ERead);
+	}
+
+void RPermanentStoreTocIter::Release()
+	{
+	iBuf.Release();
+	}
+
+void RPermanentStoreTocIter::ResetL()
+	{
+	iNext = iIndex = 1;
+	if (iBuf.Offset()<0)
+		{
+		iCount=0;
+		return;
+		}
+//
+	RReadStream stream(&iBuf);
+	STocHead h;
+	stream.ReadL((TUint8*)&h,sizeof(STocHead)); // platform dependency
+	if (h.primary<0||(h.primary&~KMaskStreamIdValue)!=0||
+		h.avail>0||(h.avail&KMaskHandleClear)!=0||(h.count&~KMaskHandleIndex)!=0)
+		__LEAVE(KErrCorrupt);
+//
+	const CPermanentStoreToc& table=iTable;
+	if (table.HasDelta())
+		{
+		TInt c = table.iEntries.Count();
+		if (c)
+			{
+			iDelta = &table.iEntries[0];
+			iDeltaEnd = iDelta + c;
+			}
+		iIndex = 0;
+		}
+	iCount = iTable.iCount;
+	}
+
+TBool RPermanentStoreTocIter::NextL(TEntry& anEntry)
+	{
+	TInt i=iIndex;
+	__ASSERT_DEBUG(iCount>=0,User::Invariant());
+	if (i == 0)
+		{
+		// report TOC-base as a 'stream'
+		anEntry.handle = KHandleTocBase;
+		anEntry.ref = iTable.iTocOff;
+		iIndex = 1;
+		return ETrue;
+		}
+
+	__ASSERT_DEBUG(i>0,User::Invariant());
+	if (i>iCount)
+		return EFalse;
+//
+	const TEntry* d = iDelta;
+	if (d != iDeltaEnd && (d->handle&KMaskHandleIndex) == i)
+		{
+		anEntry = *d;
+		iDelta = d+1;
+		iIndex = i+1;
+		return ETrue;
+		}
+//
+	RReadStream stream(&iBuf);
+	TInt skip = i - iNext;
+	if (skip > 0)
+		stream.ReadL(KSizeTocEntry * skip);
+	STocEntry e;
+	e.handle=i;
+	stream.ReadL((TUint8*)&e+KSizeHandleIndex,KSizeTocEntry); // platform dependency
+	if ((e.handle&KMaskHandleClear)!=0||e.handle>=0&&e.ref<KFrameNonexistent16||
+		e.handle<0&&(e.ref>0||(e.ref&KMaskHandleClear)!=0))
+		__LEAVE(KErrCorrupt);
+//
+	iNext = iIndex = i+1;
+	anEntry.handle=TInt(e.handle);
+	anEntry.ref=TInt(e.ref);
+	return ETrue;
+	}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+/////////////////////              TPermanentStoreCache               //////////////////////////////////////////////////////
+////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+const TPermanentStoreCache::TItem* TPermanentStoreCache::At(TInt aHandle) const
+	{
+	const TItem* item=&iItems[0];
+	TInt i=1;
+	TInt bit=1;
+	while (item->handle!=aHandle)
+		{
+		__ASSERT_DEBUG(item==&iItems[i-1],User::Invariant());
+		TInt step=(aHandle&bit)?i+1:i;
+		bit<<=1;
+		i+=step;
+		if (i>EItems)
+			return NULL;
+//
+		item+=step;
+		}
+	__ASSERT_DEBUG(item==&iItems[i-1],User::Invariant());
+	return item;
+	}
+
+void TPermanentStoreCache::Relocated(TInt aHandle,TInt anOffset)
+	{
+	const TItem* item=At(aHandle);
+	if (item)
+		{
+		// update the cache item with the new offset
+		// As 'extent' may only be a partial extent of a fragmented frame
+		// which is no longer fragmented, we cannot simply shift this by the same
+		// amount as 'offset'. Simplest to reset this to 'unknown', i.e. 0
+		const_cast<TItem*>(item)->offset = anOffset;
+		const_cast<TItem*>(item)->extent = 0;
+		}
+	}
+
+void TPermanentStoreCache::Put(const TItem* anItem,TInt anOffset,TInt anExtent)
+	{
+	TInt handle=anItem->handle;
+	TItem* item=&iItems[0];
+	TInt i=1;
+	TInt bit=1;
+	while (item != anItem)
+		{
+		__ASSERT_DEBUG(item==&iItems[i-1],User::Invariant());
+		TInt step=(handle&bit)?i+1:i;
+		bit<<=1;
+		i+=step;
+		__ASSERT_DEBUG(i<=EItems,User::Invariant());
+		item+=step;
+		}
+	__ASSERT_DEBUG(item==&iItems[i-1],User::Invariant());
+
+	for(;;)
+		{
+		__ASSERT_DEBUG(item==&iItems[i-1],User::Invariant());
+		TInt step=(handle&bit)?i+1:i;
+		bit<<=1;
+		i+=step;
+		if (i>EItems)
+			break;
+//
+		TItem* hole=item;
+		item+=step;
+		*hole=*item;
+		};
+	item->handle=handle;
+	item->offset=anOffset;
+	item->extent=anExtent;
+	__ASSERT_DEBUG(At(handle)==item,User::Invariant());
+	}
+
+void TPermanentStoreCache::Add(TInt aHandle,TInt anOffset,TInt anExtent)
+	{
+	TItem* item=&iItems[0];
+	TInt i=1;
+	TInt bit=1;
+	for(;;)
+		{
+		__ASSERT_DEBUG(item==&iItems[i-1]&&item->handle!=aHandle,User::Invariant());
+		TInt step=(aHandle&bit)?i+1:i;
+		bit<<=1;
+		i+=step;
+		if (i>EItems)
+			break;
+//
+		TItem* hole=item;
+		item+=step;
+		*hole=*item;
+		};
+	item->handle=aHandle;
+	item->offset=anOffset;
+	item->extent=anExtent;
+	__ASSERT_DEBUG(At(aHandle)==item,User::Invariant());
+	}
+
+void TPermanentStoreCache::Remove(TInt aHandle)
+	{
+	TItem* item=&iItems[0];
+	TInt i=1;
+	TInt bit=1;
+	while (item->handle!=aHandle)
+		{
+		__ASSERT_DEBUG(item==&iItems[i-1],User::Invariant());
+		TInt step=(aHandle&bit)?i+1:i;
+		bit<<=1;
+		i+=step;
+		if (i>EItems)
+			return;
+//
+		item+=step;
+		}
+	TItem* hole=item;
+	TInt mask=bit-1;
+	while (item!=&iItems[0])
+		{
+		__ASSERT_DEBUG(item==&iItems[i-1],User::Invariant());
+		TInt step=i;
+		bit>>=1;
+		i>>=1;
+		step-=i;
+		item-=step;
+//
+		if (((aHandle^item->handle)&mask)==0)
+			{
+			*hole=*item;
+			hole=item;
+			mask=bit-1;
+			}
+		}
+	hole->handle=0;
+	__ASSERT_DEBUG(i==1&&At(aHandle)==NULL,User::Invariant());
+	}
+
+void TPermanentStoreCache::Invalidate()
+	{
+	for (TItem* item=&iItems[0],*end=item+EItems;item<end;++item)
+		item->handle=0;
+	}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+/////////////////////              CPermanentStoreCoord               //////////////////////////////////////////////////////
+////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+//Returns the file system type, according to what the "file write" operation guarantees.
+//The return result could be one of:
+// - ESimple        - "single byte write" operations are atomic;
+// - EBlockAtomic   - "block/sector write" operations are atomic;
+// - ETransactional - transactional file system;
+CPermanentStoreCoord::TFileQoS CPermanentStoreCoord::FileQoSL()
+	{
+	//Uncomment, if you want FileQoSL() to return always EBlockAtomic/EBlockAtomic.
+	//iFileQos = ETransactional;	
+	//iFileQos = EBlockAtomic;	
+	//return iFileQos;
+	//
+	if (iFileQos == EUnknown) //get the file sytem type, if iFileQos is not set yet
+		{
+		TStreamExchange &se = Host();
+		RFileBuf *sb = static_cast<RFileBuf *>(se.HostL());
+		RFile &f = sb->File();
+
+		TInt dn;
+		TDriveInfo di;
+		User::LeaveIfError(f.Drive(dn, di));
+
+		iFileQos = (di.iDriveAtt & KDriveAttTransaction) ? ETransactional : ESimple;
+		
+		if(iFileQos == ESimple && IsBlockAtomicL(dn))
+			{
+			iFileQos = EBlockAtomic;	
+			}
+		}
+	return iFileQos;
+	}
+
+//The function returns true, if the file system guarantees atomic "block write" operations on aDriveNo.
+//It is not the most effective implementation at the moment (creates/closes a file session), 
+//probably TDriveInfo::iType can be used in a more effective implementation.
+TBool CPermanentStoreCoord::IsBlockAtomicL(TInt aDriveNo) const
+	{
+	__ASSERT_DEBUG(aDriveNo >= EDriveA && aDriveNo <= EDriveZ, User::Invariant());
+	RFs fs;
+	CleanupClosePushL(fs);
+	User::LeaveIfError(fs.Connect());
+	
+	TVolumeIOParamInfo volInfo;
+	TInt err = fs.VolumeIOParam(aDriveNo, volInfo);
+	CleanupStack::PopAndDestroy(&fs);
+	
+	//If VolumeIOParam() succeeds, the media block size is >= 512 bytes and the media block size is power of two - report
+	//that the media supports atomic "block write" operations.
+	return err == KErrNone && volInfo.iBlockSize >= KDefaultMediaBlockSize && (volInfo.iBlockSize & (volInfo.iBlockSize - 1)) == 0;
+	}
+
+TStreamPos CPermanentStoreCoord::LimitL()
+	{
+	TableL();
+	return RFrame16Buf::Position(Base(),iExt);
+	}
+
+TStreamId CPermanentStoreCoord::PrimaryL()
+	{
+	return TStreamId(TableL().Primary());
+	}
+
+void CPermanentStoreCoord::ChangedL()
+	{
+	ConsolidateL().Changed();
+	}
+
+TBool CPermanentStoreCoord::CommitL(TStreamId aPrimary)
+	{
+	__ASSERT_DEBUG(IsTrim(),User::Invariant());
+	if (iExtend!=0)
+		__LEAVE(KErrInUse);
+//
+	CPermanentStoreToc& table=ConsolidateL();
+	if (!table.IsVirtual())
+		return EFalse;
+//
+	iState|=EClip;
+	TInt toc=table.RealizeL(aPrimary.Value(),iExt);
+//
+	TPermanentStoreHeader header(toc);
+	header.SetBackupToc(iToc);
+	MStreamBuf* buf=BeginL(header);
+	buf->SynchL();
+		// it's done, wrap things up
+	Host().Share(buf);
+	iToc=toc;
+	table.Adopt(toc,aPrimary.Value());
+	++iGen;
+	iState=EBackup;
+	iExt=table.Extent();
+	return ETrue;
+	}
+
+TBool CPermanentStoreCoord::RevertL(TStreamId& aPrimary)
+	{
+	__ASSERT_ALWAYS(iAccess==0,Panic(EStoreInUse));
+		// can't revert things under people's feet
+	CPermanentStoreToc* table=iTable;
+	iTable=NULL;
+	iCache.Invalidate();
+	if (table==NULL||!table->IsVirtual())
+		{
+		__ASSERT_DEBUG(table==NULL||aPrimary==TStreamId(table->Primary()),User::Invariant());
+		delete table;
+		return EFalse;
+		}
+//
+	aPrimary=TStreamId(table->Primary());
+	delete table;
+	iState|=EClip;
+//
+	TStreamExchange& host=Host();
+	MStreamBuf* buf=host.HostL();
+	host.Release();
+	buf->SynchL();
+	host.Share(buf);
+	return ETrue;
+	}
+
+TStreamId CPermanentStoreCoord::ExtendL()
+	{
+	return TStreamId(ConsolidateL().AllocL(KFrameNonexistent16));
+	}
+
+void CPermanentStoreCoord::DeleteL(TStreamId anId)
+	{
+	TInt handle=anId.Value();
+	ConsolidateL().FreeL(handle);
+	iCache.Remove(handle);
+	}
+
+CPermanentStoreCoord::CPermanentStoreCoord(TStreamPos aBase,TStreamExchange& aHost)
+	: iBase(aBase),iHost(&aHost), iFileQos(EUnknown)
+	{}
+
+//
+// Read and analyse the store header.
+// The whole header (14 bytes) is read from the file and:
+// - If the dirty bit is set, the backup TOC will be used;
+// - If the dirty bit is not set, and the backup TOC ref is not the same as the TOC ref,
+//   then it means the the backup TOC ref has not been written successfully, so the TOC ref will be used;
+void CPermanentStoreCoord::InternalizeL(RReadStream& aStream)
+	{
+	if (iTable!=NULL)
+		__LEAVE(KErrNotReady);
+//
+	iState=EClip;
+	TPermanentStoreHeader header;
+	aStream.ReadL(header.Ptr(),KPermanentStoreHeaderLength);
+		// determine where the toc lives
+	TInt toc=header.BackupToc();
+	if (header.IsDirty())
+		{
+		iReloc=0;
+		iTarget=0;
+		}
+	else
+		{
+		TInt handle=header.Handle();
+		TInt ref=header.Reference();
+		if (handle==0&&toc!=ref)
+			{ // toc pointer not backed up, validate as if it was
+			toc=ref;
+			iState|=EBackup;
+			header.SetBackupToc(toc);
+			}
+		if (!header.IsValid()) // not a permanent store or damaged beyond recognition
+			__LEAVE(KErrNotSupported);
+	//
+		if (toc<0||((handle&~KMaskStreamIdValue)!=0&&handle!=KHandleTocBase)||ref<0||(handle!=0&&ref>=toc+KOffsetTocHeader))
+			__LEAVE(KErrCorrupt); // integrity compromised
+	//
+		iReloc=handle;
+		iTarget=ref;
+		}
+	//
+	if (iToc!=0 && iToc!=toc)		// refresh produced a different toc
+		__LEAVE(KErrCorrupt);
+	iToc=toc;
+	}
+
+CPermanentStoreCoord::~CPermanentStoreCoord()
+	{
+	__ASSERT_ALWAYS(iRefs==0,Panic(EStoreInUse));
+	delete iTable;
+	}
+
+void CPermanentStoreCoord::CanExtendL()
+	{
+	__ASSERT_DEBUG(IsTrim(),User::Invariant());
+	if (iExtend!=0)
+		__LEAVE(KErrInUse);
+//
+	ConsolidateL();
+	}
+
+TInt CPermanentStoreCoord::DoCreateL()
+	{
+	__ASSERT_DEBUG(IsTrim()&&iReloc==0&&iExtend==0,User::Invariant());
+	TInt handle=Table().AllocL();
+	iExtend=handle;
+	Inc();
+	++iAccess;
+	return handle;
+	}
+
+void CPermanentStoreCoord::DoReplaceL(TInt aHandle)
+	{
+	__ASSERT_DEBUG(IsTrim()&&iReloc==0&&iExtend==0,User::Invariant());
+	TInt off=Table().GetL(aHandle);
+	const TItem* item=iCache.At(aHandle);
+	__ASSERT_DEBUG(item==NULL||iTable!=NULL&&item->handle==aHandle,User::Invariant());
+	if (item==NULL)
+		iCache.Add(aHandle,off,Min(off,0));
+	iExtend=aHandle;
+	Inc();
+	++iAccess;
+	}
+
+TInt CPermanentStoreCoord::DoOpenL(TInt& anOffset,TInt aHandle)
+	{
+	const TItem* item=iCache.At(aHandle);
+	__ASSERT_DEBUG(item==NULL||iTable!=NULL&&item->handle==aHandle,User::Invariant());
+	TInt off;
+	TInt ext;
+	if (item==NULL)
+		{
+		off=TableL().AtL(aHandle);
+		if (iReloc==aHandle)
+			{
+			TInt trg=iTarget;
+			if (trg==off)
+				iReloc=0;
+			else
+				off=trg;
+			}
+		ext=Min(off,0); // ensures ext==off for empty streams
+		iCache.Add(aHandle,off,ext);
+		}
+	else
+		{
+		off=item->offset;
+		ext=item->extent;
+		}
+	Inc();
+	++iAccess;
+	anOffset=off;
+	return ext;
+	}
+
+void CPermanentStoreCoord::DoRelease(TInt aHandle,TInt anOffset,TInt anExtent)
+	{
+	__ASSERT_DEBUG(aHandle!=0,User::Invariant());
+	Dec();
+	--iAccess;
+	if (anExtent==0)
+		{ // failed to commit the extending stream
+		__ASSERT_DEBUG(aHandle==iExtend&&IsTrim(),User::Invariant());
+		iState|=EClip;
+		iExtend=0;
+		if (aHandle<0)
+			Table().Cancel(aHandle);
+		}
+	else
+		{
+		const TItem* item=iCache.At(aHandle);
+		if (item!=NULL&&item->offset==anOffset&&anExtent>item->extent)
+			iCache.Put(item,anOffset,anExtent);
+		}
+	}
+
+TInt CPermanentStoreCoord::DoCommit(TInt aHandle,TInt anOffset,TInt anExtent)
+	{
+	__ASSERT_DEBUG(aHandle!=0&&aHandle==iExtend&&(anExtent>=iExt||anOffset==anExtent),User::Invariant());
+	aHandle=Table().Set(aHandle,anOffset);
+	if (anExtent<0)
+		iCache.Remove(aHandle);
+	else
+		{
+		iExt=anExtent;
+		const TItem* item=iCache.At(aHandle);
+		if (item==NULL)
+			iCache.Add(aHandle,anOffset,anExtent);
+		else
+			iCache.Put(item,anOffset,anExtent);
+		}
+	iExtend=0;
+	return aHandle;
+	}
+
+CPermanentStoreToc& CPermanentStoreCoord::TableL()
+	{
+	CPermanentStoreToc* table=iTable;
+	if (table==NULL)
+		{
+		table=CPermanentStoreToc::NewL(Base(),Host(),iToc,iReloc==KHandleTocBase?iTarget:KFrameNonexistent16);
+		iExt=table->Extent();
+		iTable=table;
+		}
+	return *table;
+	}
+
+CPermanentStoreToc& CPermanentStoreCoord::ConsolidateL()
+	{
+	CPermanentStoreToc& table=TableL();
+	if (iReloc!=0)
+		{
+		table.PutL(iReloc,iTarget,CPermanentStoreToc::ETestBeforeWrite);
+		iCache.Relocated(iReloc,iTarget);
+		iReloc=0;
+		}
+	return table;
+	}
+
+//After stream relocation, the stream entry in the TOC has to be updated with the new stream position.
+//If the file system is not transactional or if the file system is "block atomic", but the stream entry is split
+//on a block/sector boundary, then the stream handle will be stored in the permanent file store header, in case
+//if the TOC entry update fails.
+void CPermanentStoreCoord::RelocateL(TInt aHandle,TInt anOffset)
+	{
+	__ASSERT_DEBUG(!Accessed(),User::Invariant());
+	__ASSERT_DEBUG(iReloc==0,User::Invariant());
+
+	TBool updateStoreHeader = ETrue;	
+	TFileQoS fileQos = FileQoSL();
+	if(fileQos == ETransactional)
+		{
+		updateStoreHeader = EFalse;	
+		}
+	else if(fileQos == EBlockAtomic)
+		{
+		TInt dataLen = 0;
+		TInt writePos = iTable->RefSpan(aHandle, dataLen);
+		__ASSERT_DEBUG(writePos >= 0 && dataLen > 0, User::Invariant());
+		TInt startSectorAddr = writePos & ~(KDefaultMediaBlockSize - 1);
+		TInt endSectorAddr = (writePos + dataLen - 1) & ~(KDefaultMediaBlockSize - 1);
+		if(startSectorAddr == endSectorAddr)
+			{
+			updateStoreHeader = EFalse;	
+			}
+		}
+	
+	if (updateStoreHeader)
+		{
+		TPermanentStoreHeader header(iToc,aHandle,anOffset);
+		Host().Share(BeginL(header));
+		iReloc=aHandle;
+		iTarget=anOffset;
+		}
+	++iGen;
+	iTable->PutL(aHandle,anOffset,CPermanentStoreToc::EWrite);
+	iCache.Relocated(aHandle,anOffset);
+	iReloc=0;
+	}
+
+void CPermanentStoreCoord::MoveL(TInt aToc,TInt anExtent)
+	{
+	__ASSERT_DEBUG(iReloc==0,User::Invariant());
+	CPermanentStoreToc& table=Table();
+	TPermanentStoreHeader header(aToc);
+	header.SetBackupToc(iToc);
+	Host().Share(BeginL(header));
+		// update data structures but defer the write
+	iToc=aToc;
+	TInt ext=table.Extent();
+	table.Move(aToc,anExtent);
+	iState|=EBackup;
+	if (iExt==ext)
+		{
+		iExt=anExtent;
+		iState|=EClip;
+		}
+	}
+
+//
+// Starts a pseudo-atomic update of the permanent file store header.
+//
+// For the effect to be 'atomic', writes need to meet the following requirements:
+// 1. When updating n bytes using a single write, bytes 2 through n remain unchanged unless the first byte also changes.
+// 2. Changes associated with successive write requests happen in strict sequence.
+// 3. Updating a single byte is atomic.
+//
+// Also, a failure to write to a location shall be reported no later than on the next
+// write to that or a different location, or on buffer synchronisation.
+//
+// The preconditions of the operation are:
+// - all stream insert/delete/relocate operations completed, file - updated;
+// - the TOC reference in the file store header points to the current (valid) TOC, which does not include the most recent
+//   changes, since the last commit;
+// - the in-memory backup TOC reference updated and made equal to the file stored TOC reference;
+//
+// The procedure consists of 3 "file-write" steps:
+// -1- write the backup TOC ref (4 bytes) to the permanent file store header.
+//     if this operation fails, when the store is reopened, the TOC ref will be used;
+// -2- set the dirty bit and write the whole file store header (14 bytes).
+//     If this operation fails, but the dirty bit has been successfully set, the backup TOC ref will be used,
+//     when the store is reopened;
+// -3- clear the dirty bit (1 byte "file write" op). The commit operation has completed successfully;
+MStreamBuf* CPermanentStoreCoord::BeginL(TPermanentStoreHeader& aHeader)
+	{
+	__ASSERT_DEBUG(!aHeader.IsDirty()&&aHeader.BackupToc()==iToc&&iReloc==0,User::Invariant());
+	MStreamBuf& buf=*Host().HostL();
+	buf.SeekL(buf.EWrite,Base()+KPermanentStoreHeaderOffset);
+	TFileQoS fileQos = FileQoSL();
+	if (fileQos<EBlockAtomic)
+		{
+		if (iState&EBackup)
+			{ // we've yet to write the backup toc, do that before clobbering the header
+			buf.WriteL(aHeader.Ptr(),KPermanentStoreBackupLength);
+			buf.SeekL(buf.EWrite,EStreamBeginning);
+			buf.SeekL(buf.EWrite,Base()+KPermanentStoreHeaderOffset);
+			iState&=~EBackup;
+			}
+		// first write--dirty flag set in the first byte, backup toc unchanged, new header otherwise
+		aHeader.MarkDirty();
+		}
+	Host().Release(); // from this point onwards any failure results in store shutdown
+//
+	buf.WriteL(aHeader.Ptr(),KPermanentStoreHeaderLength);
+	if (fileQos<EBlockAtomic)
+		{
+		buf.SeekL(buf.EWrite,EStreamBeginning);
+		buf.SeekL(buf.EWrite,Base()+KPermanentStoreHeaderOffset);
+		aHeader.SetBackupToc(iToc);
+			// second write--single byte write to clear the dirty flag, no change otherwise
+		buf.WriteL(aHeader.Ptr(),1);
+		}
+		// at this point synchronisation is atomic; ie, if successful the change
+		// has been recorded, and failure means it will never happen
+	return &buf;
+	}
+
+////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+/////////////////////              HPermanentStoreBuf               ////////////////////////////////////////////////////////
+////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+HPermanentStoreBuf* HPermanentStoreBuf::CreateL(CPermanentStoreCoord& aCoord,TStreamId& anId,TInt aMode)
+	{
+	HPermanentStoreBuf* buf=ExtendLC(aCoord,aMode);
+	TInt handle=aCoord.DoCreateL();
+	buf->iHandle=handle;
+	CleanupStack::Pop();
+	anId=TStreamId(handle&KMaskStreamIdValue);
+	return buf;
+	}
+
+HPermanentStoreBuf* HPermanentStoreBuf::ReplaceL(CPermanentStoreCoord& aCoord,TStreamId anId,TInt aMode)
+	{
+	HPermanentStoreBuf* buf=ExtendLC(aCoord,aMode);
+	TInt handle=anId.Value();
+	aCoord.DoReplaceL(handle);
+	buf->iHandle=handle;
+	CleanupStack::Pop();
+	return buf;
+	}
+
+HPermanentStoreBuf* HPermanentStoreBuf::OpenL(CPermanentStoreCoord& aCoord,TStreamId anId,TInt aMode)
+	{
+	HPermanentStoreBuf* buf=NewLC(aCoord);
+	TInt handle=anId.Value();
+	TInt off=KFrameNonexistent16;
+	TInt ext=aCoord.DoOpenL(off,handle);
+	buf->iHandle=handle;
+	if (ext!=0)
+		buf->RFrame16Buf::Set(aCoord.Host(),off,ext,EFrameData16|aMode);
+	else
+		buf->RFrame16Buf::OpenL(aCoord.Host(),off,EFrameData16|aMode);
+	CleanupStack::Pop();
+	return buf;
+	}
+
+HPermanentStoreBuf::~HPermanentStoreBuf()
+	{
+	TInt handle=iHandle;
+	if (handle!=0)
+		Coord().DoRelease(handle,Offset(),Extent());
+	RFrame16Buf::DoRelease();
+	}
+
+HPermanentStoreBuf* HPermanentStoreBuf::NewLC(CPermanentStoreCoord& aCoord)
+	{
+	HPermanentStoreBuf* buf=new(ELeave) HPermanentStoreBuf(aCoord);
+	buf->PushL();
+	return buf;
+	}
+
+HPermanentStoreBuf* HPermanentStoreBuf::ExtendLC(CPermanentStoreCoord& aCoord,TInt aMode)
+	{
+	aCoord.CanExtendL();
+	HPermanentStoreBuf* buf=NewLC(aCoord);
+	buf->RFrame16Buf::ExtendL(aCoord.Host(),aCoord.iExt,EFrameData16|aMode);
+	__ASSERT_DEBUG(TStreamPos(aCoord.Host().SizeL())==buf->Position(buf->Offset()),User::Invariant());
+	return buf;
+	}
+
+void HPermanentStoreBuf::DoRelease()
+	{
+	delete this;
+	}
+
+void HPermanentStoreBuf::DoSynchL()
+	{
+	__ASSERT_DEBUG(iHandle!=0,User::Invariant());
+	if (IsCommitted())
+		return;
+//
+	CommitL();
+	iHandle=Coord().DoCommit(iHandle,Offset(),Extent());
+	}
+