Adding upstream version 4:7.4.7.upstream/4%7.4.7upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

18 files changed, 9637 insertions, 0 deletions

diff --git a/sot/source/sdstor/stg.cxx b/sot/source/sdstor/stg.cxx
new file mode 100644
index 000000000..08af34309
--- /dev/null
+++ b/sot/source/sdstor/stg.cxx
@@ -0,0 +1,939 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+
+#include <sot/storinfo.hxx>
+#include <osl/file.hxx>
+#include <unotools/tempfile.hxx>
+#include <tools/stream.hxx>
+#include <tools/debug.hxx>
+
+#include <sot/stg.hxx>
+#include <utility>
+#include "stgelem.hxx"
+#include "stgdir.hxx"
+#include "stgio.hxx"
+#include "stgole.hxx"
+
+static tools::Long nTmpCount = 0;
+
+// The internal open mode is StreamMode::READ | StreamMode::TRUNC, which is silly
+// by itself. It inhibits the checking of sharing modes and is used
+// during CopyTo() and MoveTo() for opening a stream in read mode
+// although it may be open in DENYALL mode
+
+#define INTERNAL_MODE ( StreamMode::READ | StreamMode::TRUNC )
+
+///////////////////////// class StorageBase
+
+
+StorageBase::StorageBase()
+    : m_bAutoCommit( false )
+{
+    m_nMode  = StreamMode::READ;
+    m_nError = ERRCODE_NONE;
+}
+
+StorageBase::~StorageBase()
+{
+}
+
+// The following three methods are declared as const, since they
+// may be called from within a const method.
+
+ErrCode StorageBase::GetError() const
+{
+    const ErrCode n = m_nError;
+    m_nError = ERRCODE_NONE;
+    return n;
+}
+
+void StorageBase::SetError( ErrCode n ) const
+{
+    if( !m_nError )
+        m_nError = n;
+}
+
+void StorageBase::ResetError() const
+{
+    m_nError = ERRCODE_NONE;
+}
+
+OLEStorageBase::OLEStorageBase( StgIo* p, StgDirEntry* pe, StreamMode& nMode )
+    : nStreamMode( nMode ), pIo( p ), pEntry( pe )
+{
+    if ( p )
+        p->IncRef();
+    if( pe )
+        pe->m_nRefCnt++;
+}
+
+OLEStorageBase::~OLEStorageBase()
+{
+    if( pEntry )
+    {
+        DBG_ASSERT( pEntry->m_nRefCnt, "RefCount under 0" );
+        if( !--pEntry->m_nRefCnt )
+        {
+            if( pEntry->m_bZombie )
+                delete pEntry;
+            else
+                pEntry->Close();
+        }
+
+        pEntry = nullptr;
+    }
+
+
+    if( pIo && !pIo->DecRef() )
+    {
+        delete pIo;
+        pIo = nullptr;
+    }
+}
+
+// Validate the instance for I/O
+
+bool OLEStorageBase::Validate_Impl( bool bWrite ) const
+{
+    return pIo
+        && pIo->m_pTOC
+        && pEntry
+        && !pEntry->m_bInvalid
+        &&  ( !bWrite || !pEntry->m_bDirect || ( nStreamMode & StreamMode::WRITE ) );
+}
+
+bool OLEStorageBase::ValidateMode_Impl( StreamMode m, StgDirEntry const * p )
+{
+    if( m == INTERNAL_MODE )
+        return true;
+    StreamMode nCurMode = ( p && p->m_nRefCnt ) ? p->m_nMode : StreamMode::SHARE_DENYALL;
+    if( ( m & StreamMode::READWRITE ) == StreamMode::READ )
+    {
+        // only SHARE_DENYWRITE or SHARE_DENYALL allowed
+        if( ( ( m & StreamMode::SHARE_DENYWRITE )
+           && ( nCurMode & StreamMode::SHARE_DENYWRITE ) )
+         || ( ( m & StreamMode::SHARE_DENYALL )
+           && ( nCurMode & StreamMode::SHARE_DENYALL ) ) )
+            return true;
+    }
+    else
+    {
+        // only SHARE_DENYALL allowed
+        // storages open in r/o mode are OK, since only
+        // the commit may fail
+        if( ( m & StreamMode::SHARE_DENYALL )
+         && ( nCurMode & StreamMode::SHARE_DENYALL ) )
+            return true;
+    }
+    return false;
+}
+
+
+//////////////////////// class StorageStream
+
+
+StorageStream::StorageStream( StgIo* p, StgDirEntry* q, StreamMode m )
+             : OLEStorageBase( p, q, m_nMode ), nPos( 0 )
+{
+    // The dir entry may be 0; this means that the stream is invalid.
+    if( q && p )
+    {
+        if( q->m_nRefCnt == 1 )
+        {
+            q->m_nMode = m;
+            q->OpenStream( *p );
+        }
+    }
+    else
+        m &= ~StreamMode::READWRITE;
+    m_nMode = m;
+}
+
+StorageStream::~StorageStream()
+{
+    // Do an auto-commit if the entry is open in direct mode
+    if( m_bAutoCommit )
+        Commit();
+    if( pEntry && pEntry->m_nRefCnt && pEntry->m_bDirect && (m_nMode & StreamMode::WRITE) )
+        pEntry->Commit();
+}
+
+bool StorageStream::Equals( const BaseStorageStream& rStream ) const
+{
+    const StorageStream* pOther =  dynamic_cast<const StorageStream*>( &rStream );
+    return pOther && ( pOther->pEntry == pEntry );
+}
+
+sal_Int32 StorageStream::Read( void* pData, sal_Int32 nSize )
+{
+    if( Validate() )
+    {
+        pEntry->Seek( nPos );
+        nSize = pEntry->Read( pData, nSize );
+        pIo->MoveError( *this );
+        nPos += nSize;
+    }
+    else
+        nSize = 0;
+    return nSize;
+}
+
+sal_Int32 StorageStream::Write( const void* pData, sal_Int32 nSize )
+{
+    if( Validate( true ) )
+    {
+        pEntry->Seek( nPos );
+        nSize = pEntry->Write( pData, nSize );
+        pIo->MoveError( *this );
+        nPos += nSize;
+    }
+    else
+        nSize = 0;
+    return nSize;
+}
+
+sal_uInt64 StorageStream::Seek( sal_uInt64 n )
+{
+    if( Validate() )
+    {
+        nPos = pEntry->Seek( n );
+        return nPos;
+    }
+    else
+        return n;
+}
+
+void StorageStream::Flush()
+{
+    // Flushing means committing, since streams are never transacted
+    Commit();
+}
+
+bool StorageStream::SetSize( sal_uInt64 nNewSize )
+{
+    if( Validate( true ) )
+    {
+        bool b = pEntry->SetSize( nNewSize );
+        pIo->MoveError( *this );
+        return b;
+    }
+    else
+        return false;
+}
+
+sal_uInt64 StorageStream::GetSize() const
+{
+    if( Validate() )
+        return pEntry->GetSize();
+    return 0;
+}
+
+bool StorageStream::Commit()
+{
+    if( !Validate() )
+        return false;
+    if( !( m_nMode & StreamMode::WRITE ) )
+    {
+        SetError( SVSTREAM_ACCESS_DENIED );
+        return false;
+    }
+    else
+    {
+        pEntry->Commit();
+        pIo->MoveError( *this );
+        return Good();
+    }
+}
+
+void StorageStream::CopyTo( BaseStorageStream* pDest )
+{
+    if( !Validate() || !pDest || !pDest->Validate( true ) || Equals( *pDest ) )
+        return;
+    pEntry->Copy( *pDest );
+    pDest->Commit();
+    pIo->MoveError( *this );
+    SetError( pDest->GetError() );
+}
+
+bool StorageStream::Validate( bool bValidate ) const
+{
+    bool bRet = Validate_Impl( bValidate );
+    if ( !bRet )
+        SetError( SVSTREAM_ACCESS_DENIED );
+    return bRet;
+}
+
+bool StorageStream::ValidateMode( StreamMode nMode ) const
+{
+    bool bRet = ValidateMode_Impl( nMode );
+    if ( !bRet )
+        SetError( SVSTREAM_ACCESS_DENIED );
+    return bRet;
+}
+
+///////////////////////// class SvStorageInfo
+
+SvStorageInfo::SvStorageInfo( const StgDirEntry& rE )
+{
+    rE.m_aEntry.GetName( aName );
+    bStorage = rE.m_aEntry.GetType() == STG_STORAGE;
+    bStream  = rE.m_aEntry.GetType() == STG_STREAM;
+    nSize    = bStorage ? 0 : rE.m_aEntry.GetSize();
+}
+
+/////////////////////////// class Storage
+
+bool Storage::IsStorageFile( const OUString & rFileName )
+{
+    StgIo aIo;
+    if( aIo.Open( rFileName, StreamMode::STD_READ ) )
+        return aIo.Load();
+    return false;
+}
+
+bool Storage::IsStorageFile( SvStream* pStream )
+{
+    bool bRet = false;
+
+    if ( pStream )
+    {
+        StgHeader aHdr;
+        sal_uInt64 nPos = pStream->Tell();
+        bRet = ( aHdr.Load( *pStream ) && aHdr.Check() );
+
+        // It's not a stream error if it is too small for an OLE storage header
+        if ( pStream->GetErrorCode() == ERRCODE_IO_CANTSEEK )
+            pStream->ResetError();
+        pStream->Seek( nPos );
+    }
+
+    return bRet;
+}
+
+// Open the storage file. If writing is permitted and the file is not
+// a storage file, initialize it.
+
+
+Storage::Storage( OUString aFile, StreamMode m, bool bDirect )
+    : OLEStorageBase( new StgIo, nullptr, m_nMode )
+    , aName(std::move( aFile )), bIsRoot( false )
+{
+    bool bTemp = false;
+    if( aName.isEmpty() )
+    {
+        // no name = temporary name!
+        aName = utl::TempFile::CreateTempName();
+        bTemp = true;
+    }
+    // the root storage creates the I/O system
+    m_nMode = m;
+    if( pIo->Open( aName, m ) )
+    {
+        Init( ( m & ( StreamMode::TRUNC | StreamMode::NOCREATE ) ) == StreamMode::TRUNC );
+        if( pEntry )
+        {
+            pEntry->m_bDirect = bDirect;
+            pEntry->m_nMode = m;
+            pEntry->m_bTemp = bTemp;
+        }
+    }
+    else
+    {
+        pIo->MoveError( *this );
+        pEntry = nullptr;
+    }
+}
+
+// Create a storage on a given stream.
+
+Storage::Storage( SvStream& r, bool bDirect )
+    : OLEStorageBase( new StgIo, nullptr, m_nMode )
+    , bIsRoot( false )
+{
+    m_nMode = StreamMode::READ;
+    if( r.IsWritable() )
+        m_nMode = StreamMode::READ | StreamMode::WRITE;
+    if( r.GetError() == ERRCODE_NONE )
+    {
+        pIo->SetStrm( &r, false );
+        sal_uInt64 nSize = r.TellEnd();
+        r.Seek( 0 );
+        // Initializing is OK if the stream is empty
+        Init( nSize == 0 );
+        if( pEntry )
+        {
+            pEntry->m_bDirect = bDirect;
+            pEntry->m_nMode = m_nMode;
+        }
+        pIo->MoveError( *this );
+    }
+    else
+    {
+        SetError( r.GetError() );
+        pEntry = nullptr;
+    }
+}
+
+
+Storage::Storage( UCBStorageStream& rStrm, bool bDirect )
+       : OLEStorageBase( new StgIo, nullptr, m_nMode ), bIsRoot( false )
+{
+    m_nMode = StreamMode::READ;
+
+    if ( rStrm.GetError() != ERRCODE_NONE )
+    {
+        SetError( rStrm.GetError() );
+        pEntry = nullptr;
+        return;
+    }
+
+    SvStream* pStream = rStrm.GetModifySvStream();
+    if ( !pStream )
+    {
+        OSL_FAIL( "UCBStorageStream can not provide SvStream implementation!" );
+        SetError( SVSTREAM_GENERALERROR );
+        pEntry = nullptr;
+        return;
+    }
+
+    if( pStream->IsWritable() )
+        m_nMode = StreamMode::READ | StreamMode::WRITE;
+
+    pIo->SetStrm( &rStrm );
+
+    sal_uInt64 nSize = pStream->TellEnd();
+    pStream->Seek( 0 );
+    // Initializing is OK if the stream is empty
+    Init( nSize == 0 );
+    if( pEntry )
+    {
+        pEntry->m_bDirect = bDirect;
+        pEntry->m_nMode = m_nMode;
+    }
+
+    pIo->MoveError( *this );
+}
+
+
+// Perform common code for both ctors above.
+
+void Storage::Init( bool bCreate )
+{
+    pEntry = nullptr;
+    bool bHdrLoaded = false;
+    bIsRoot = true;
+
+    OSL_ENSURE( pIo, "The pointer may not be empty at this point!" );
+    if( pIo->Good() && pIo->GetStrm() )
+    {
+        sal_uInt64 nSize = pIo->GetStrm()->TellEnd();
+        pIo->GetStrm()->Seek( 0 );
+        if( nSize )
+        {
+            bHdrLoaded = pIo->Load();
+            if( !bHdrLoaded && !bCreate  )
+            {
+                // File is not a storage and not empty; do not destroy!
+                SetError( SVSTREAM_FILEFORMAT_ERROR );
+                return;
+            }
+        }
+    }
+    // file is a storage, empty or should be overwritten
+    pIo->ResetError();
+    // we have to set up the data structures, since
+    // the file is empty
+    if( !bHdrLoaded )
+        pIo->Init();
+    if( pIo->Good() && pIo->m_pTOC )
+    {
+        pEntry = pIo->m_pTOC->GetRoot();
+        pEntry->m_nRefCnt++;
+    }
+}
+
+// Internal ctor
+
+Storage::Storage( StgIo* p, StgDirEntry* q, StreamMode m )
+       : OLEStorageBase( p, q, m_nMode ), bIsRoot( false )
+{
+    if( q )
+        q->m_aEntry.GetName( aName );
+    else
+        m &= ~StreamMode::READWRITE;
+    m_nMode   = m;
+    if( q && q->m_nRefCnt == 1 )
+        q->m_nMode = m;
+}
+
+Storage::~Storage()
+{
+    // Invalidate all open substorages
+    if( m_bAutoCommit )
+        Commit();
+    if( pEntry )
+    {
+        // Do an auto-commit if the entry is open in direct mode
+        if( pEntry->m_nRefCnt && pEntry->m_bDirect && (m_nMode & StreamMode::WRITE) )
+            Commit();
+        if( pEntry->m_nRefCnt == 1 )
+            pEntry->Invalidate(false);
+    }
+    // close the stream is root storage
+    if( bIsRoot )
+        pIo->Close();
+    // remove the file if temporary root storage
+    if( bIsRoot && pEntry && pEntry->m_bTemp )
+    {
+        osl::File::remove( GetName() );
+    }
+}
+
+const OUString& Storage::GetName() const
+{
+    if( !bIsRoot && Validate() )
+        pEntry->m_aEntry.GetName( const_cast<Storage*>(this)->aName );
+    return aName;
+}
+
+// Fill in the info list for this storage
+
+void Storage::FillInfoList( SvStorageInfoList* pList ) const
+{
+    if( !(Validate() && pList) )
+        return;
+
+    StgIterator aIter( *pEntry );
+    StgDirEntry* p = aIter.First();
+    while( p )
+    {
+        if( !p->m_bInvalid )
+        {
+            SvStorageInfo aInfo( *p );
+            pList->push_back( aInfo );
+        }
+        p = aIter.Next();
+    }
+}
+
+// Open or create a substorage
+
+BaseStorage* Storage::OpenUCBStorage( const OUString& rName, StreamMode m, bool bDirect )
+{
+    OSL_FAIL("Not supported!");
+    return OpenStorage( rName, m, bDirect );
+}
+
+BaseStorage* Storage::OpenOLEStorage( const OUString& rName, StreamMode m, bool bDirect )
+{
+    return OpenStorage( rName, m, bDirect );
+}
+
+BaseStorage* Storage::OpenStorage( const OUString& rName, StreamMode m, bool bDirect )
+{
+    if( !Validate() || !ValidateMode( m ) )
+        return new Storage( pIo, nullptr, m );
+    if( bDirect && !pEntry->m_bDirect )
+        bDirect = false;
+
+    StgDirEntry* p = StgDirStrm::Find( *pEntry, rName );
+    if( !p )
+    {
+        if( !( m & StreamMode::NOCREATE ) )
+        {
+            bool bTemp = false;
+            // create a new storage
+            OUString aNewName = rName;
+            if( aNewName.isEmpty() )
+            {
+                aNewName = "Temp Stg " + OUString::number( ++nTmpCount );
+                bTemp = true;
+            }
+            p = pIo->m_pTOC->Create( *pEntry, aNewName, STG_STORAGE );
+            if( p )
+                p->m_bTemp = bTemp;
+        }
+        if( !p )
+            pIo->SetError( ( m & StreamMode::WRITE )
+                             ? SVSTREAM_CANNOT_MAKE : SVSTREAM_FILE_NOT_FOUND );
+    }
+    else if( !ValidateMode( m, p ) )
+        p = nullptr;
+    if( p && p->m_aEntry.GetType() != STG_STORAGE )
+    {
+        pIo->SetError( SVSTREAM_FILE_NOT_FOUND );
+        p = nullptr;
+    }
+
+    // Either direct or transacted mode is supported
+    if( p && pEntry->m_nRefCnt == 1 )
+        p->m_bDirect = bDirect;
+
+    // Don't check direct conflict if opening readonly
+    if( p && (m & StreamMode::WRITE ))
+    {
+        if( p->m_bDirect != bDirect )
+            SetError( SVSTREAM_ACCESS_DENIED );
+    }
+    Storage* pStg = new Storage( pIo, p, m );
+    pIo->MoveError( *pStg );
+    if( m & StreamMode::WRITE ) pStg->m_bAutoCommit = true;
+    return pStg;
+}
+
+// Open a stream
+
+BaseStorageStream* Storage::OpenStream( const OUString& rName, StreamMode m, bool )
+{
+    if( !Validate() || !ValidateMode( m ) )
+        return new StorageStream( pIo, nullptr, m );
+    StgDirEntry* p = StgDirStrm::Find( *pEntry, rName );
+    bool bTemp = false;
+    if( !p )
+    {
+        if( !( m & StreamMode::NOCREATE ) )
+        {
+            // create a new stream
+            // make a name if the stream is temporary (has no name)
+            OUString aNewName( rName );
+            if( aNewName.isEmpty() )
+            {
+                aNewName = "Temp Strm " + OUString::number( ++nTmpCount );
+                bTemp = true;
+            }
+            p = pIo->m_pTOC->Create( *pEntry, aNewName, STG_STREAM );
+        }
+        if( !p )
+            pIo->SetError( ( m & StreamMode::WRITE )
+                           ? SVSTREAM_CANNOT_MAKE : SVSTREAM_FILE_NOT_FOUND );
+    }
+    else if( !ValidateMode( m, p ) )
+        p = nullptr;
+    // coverity[Resource leak : FALSE] - "Create" method is called with STG_STREAM line 620,
+    // so we won't enter into this "if" block here.
+    if( p && p->m_aEntry.GetType() != STG_STREAM )
+    {
+        pIo->SetError( SVSTREAM_FILE_NOT_FOUND );
+        p = nullptr;
+    }
+    if( p )
+    {
+        p->m_bTemp = bTemp;
+        p->m_bDirect = pEntry->m_bDirect;
+    }
+    StorageStream* pStm = new StorageStream( pIo, p, m );
+    if( p && !p->m_bDirect )
+        pStm->SetAutoCommit( true );
+    pIo->MoveError( *pStm );
+    return pStm;
+}
+
+// Delete a stream or substorage by setting the temp bit.
+
+void Storage::Remove( const OUString& rName )
+{
+    if( !Validate( true ) )
+        return;
+    StgDirEntry* p = StgDirStrm::Find( *pEntry, rName );
+    if( p )
+    {
+        p->Invalidate( true );
+    }
+    else
+    {
+        SetError( SVSTREAM_FILE_NOT_FOUND );
+    }
+}
+
+// Copy one element
+
+bool Storage::CopyTo( const OUString& rElem, BaseStorage* pDest, const OUString& rNew )
+{
+    if( !Validate() || !pDest || !pDest->Validate( true ) )
+        return false;
+    StgDirEntry* pElem = StgDirStrm::Find( *pEntry, rElem );
+    if( pElem )
+    {
+        if( pElem->m_aEntry.GetType() == STG_STORAGE )
+        {
+            // copy the entire storage
+            tools::SvRef<BaseStorage> p1 = OpenStorage( rElem, INTERNAL_MODE );
+            tools::SvRef<BaseStorage> p2 = pDest->OpenOLEStorage( rNew, StreamMode::WRITE | StreamMode::SHARE_DENYALL, pEntry->m_bDirect );
+
+            if ( p2 )
+            {
+                ErrCode nTmpErr = p2->GetError();
+                if( !nTmpErr )
+                {
+                    p2->SetClassId( p1->GetClassId() );
+                    p1->CopyTo( p2.get() );
+                    SetError( p1->GetError() );
+
+                    nTmpErr = p2->GetError();
+                    if( !nTmpErr )
+                        p2->Commit();
+                    else
+                        pDest->SetError( nTmpErr );
+                }
+                else
+                    pDest->SetError( nTmpErr );
+            }
+
+            return Good() && pDest->Good();
+        }
+        else
+        {
+            // stream copy
+            tools::SvRef<BaseStorageStream> p1 = OpenStream( rElem, INTERNAL_MODE );
+            tools::SvRef<BaseStorageStream> p2 = pDest->OpenStream( rNew, StreamMode::WRITE | StreamMode::SHARE_DENYALL, pEntry->m_bDirect );
+
+            if ( p2 )
+            {
+                ErrCode nTmpErr = p2->GetError();
+                if( !nTmpErr )
+                {
+                    p1->CopyTo( p2.get() );
+                    SetError( p1->GetError() );
+
+                    nTmpErr = p2->GetError();
+                    if( !nTmpErr )
+                        p2->Commit();
+                    else
+                        pDest->SetError( nTmpErr );
+                }
+                else
+                    pDest->SetError( nTmpErr );
+            }
+
+            return Good() && pDest->Good();
+        }
+    }
+    SetError( SVSTREAM_FILE_NOT_FOUND );
+    return false;
+}
+
+bool Storage::CopyTo( BaseStorage* pDest ) const
+{
+    if( !Validate() || !pDest || !pDest->Validate( true ) || Equals( *pDest ) )
+    {
+        SetError( SVSTREAM_ACCESS_DENIED );
+        return false;
+    }
+    Storage* pThis = const_cast<Storage*>(this);
+    pDest->SetClassId( GetClassId() );
+    pDest->SetDirty();
+    SvStorageInfoList aList;
+    FillInfoList( &aList );
+    bool bRes = true;
+    for( size_t i = 0; i < aList.size() && bRes; i++ )
+    {
+        SvStorageInfo& rInfo = aList[ i ];
+        bRes = pThis->CopyTo( rInfo.GetName(), pDest, rInfo.GetName() );
+    }
+    if( !bRes )
+        SetError( pDest->GetError() );
+    return Good() && pDest->Good();
+}
+
+bool Storage::IsStorage( const OUString& rName ) const
+{
+    if( Validate() )
+    {
+        StgDirEntry* p = StgDirStrm::Find( *pEntry, rName );
+        if( p )
+            return p->m_aEntry.GetType() == STG_STORAGE;
+    }
+    return false;
+}
+
+bool Storage::IsStream( const OUString& rName ) const
+{
+    if( Validate() )
+    {
+        StgDirEntry* p = StgDirStrm::Find( *pEntry, rName );
+        if( p )
+            return p->m_aEntry.GetType() == STG_STREAM;
+    }
+    return false;
+}
+
+bool Storage::IsContained( const OUString& rName ) const
+{
+    if( Validate() )
+        return StgDirStrm::Find( *pEntry, rName ) != nullptr;
+    else
+        return false;
+}
+
+// Commit all sub-elements within this storage. If this is
+// the root, commit the FAT, the TOC and the header as well.
+
+bool Storage::Commit()
+{
+    bool bRes = true;
+    if( !Validate() )
+        return false;
+    if( !( m_nMode & StreamMode::WRITE ) )
+    {
+        SetError( SVSTREAM_ACCESS_DENIED );
+        return false;
+    }
+    else
+    {
+        // Also commit the sub-streams and Storages
+        StgIterator aIter( *pEntry );
+        for( StgDirEntry* p = aIter.First(); p && bRes; p = aIter.Next() )
+            bRes = p->Commit();
+        if( bRes && bIsRoot )
+        {
+            bRes = pEntry->Commit();
+            if( bRes )
+                bRes = pIo->CommitAll();
+        }
+        pIo->MoveError( *this );
+    }
+    return bRes;
+}
+
+bool Storage::Revert()
+{
+    return true;
+}
+
+///////////////////////////// OLE Support
+
+// Set the storage type
+
+void Storage::SetClass( const SvGlobalName & rClass,
+                        SotClipboardFormatId nOriginalClipFormat,
+                        const OUString & rUserTypeName )
+{
+    if( Validate( true ) )
+    {
+        // set the class name in the root entry
+        pEntry->m_aEntry.SetClassId( rClass.GetCLSID() );
+        pEntry->SetDirty();
+        // then create the streams
+        StgCompObjStream aCompObj( *this, true );
+        aCompObj.GetClsId() = rClass.GetCLSID();
+        aCompObj.GetCbFormat() = nOriginalClipFormat;
+        aCompObj.GetUserName() = rUserTypeName;
+        if( !aCompObj.Store() )
+            SetError( aCompObj.GetError() );
+        else
+        {
+            StgOleStream aOle(*this);
+            if( !aOle.Store() )
+                SetError( aOle.GetError() );
+        }
+    }
+    else
+        SetError( SVSTREAM_ACCESS_DENIED );
+}
+
+SvGlobalName Storage::GetClassName()
+{
+    StgCompObjStream aCompObj( *this, false );
+    if( aCompObj.Load() )
+        return SvGlobalName( aCompObj.GetClsId() );
+    pIo->ResetError();
+
+    if ( pEntry )
+        return SvGlobalName( pEntry->m_aEntry.GetClassId() );
+
+    return SvGlobalName();
+}
+
+SotClipboardFormatId Storage::GetFormat()
+{
+    StgCompObjStream aCompObj( *this, false );
+    if( aCompObj.Load() )
+        return aCompObj.GetCbFormat();
+    pIo->ResetError();
+    return SotClipboardFormatId::NONE;
+}
+
+OUString Storage::GetUserName()
+{
+    StgCompObjStream aCompObj( *this, false );
+    if( aCompObj.Load() )
+        return aCompObj.GetUserName();
+    pIo->ResetError();
+    return OUString();
+}
+
+bool Storage::ValidateFAT()
+{
+    FatError nErr = pIo->ValidateFATs();
+    return nErr == FatError::Ok;
+}
+
+void Storage::SetDirty()
+{
+    if ( pEntry )
+        pEntry->SetDirty();
+}
+
+void Storage::SetClassId( const ClsId& rId )
+{
+    if ( pEntry )
+        pEntry->m_aEntry.SetClassId( rId );
+}
+
+const ClsId& Storage::GetClassId() const
+{
+    if ( pEntry )
+        return pEntry->m_aEntry.GetClassId();
+
+    static const ClsId aDummyId = {0,0,0,{0,0,0,0,0,0,0,0}};
+    return aDummyId;
+}
+
+bool Storage::Validate( bool bValidate ) const
+{
+    bool bRet = Validate_Impl( bValidate );
+    if ( !bRet )
+        SetError( SVSTREAM_ACCESS_DENIED );
+    return bRet;
+}
+
+bool Storage::ValidateMode( StreamMode nMode ) const
+{
+    bool bRet = ValidateMode_Impl( nMode );
+    if ( !bRet )
+        SetError( SVSTREAM_ACCESS_DENIED );
+    return bRet;
+}
+
+bool Storage::ValidateMode( StreamMode nMode, StgDirEntry const * p ) const
+{
+    bool bRet = ValidateMode_Impl( nMode, p );
+    if ( !bRet )
+        SetError( SVSTREAM_ACCESS_DENIED );
+    return bRet;
+}
+
+bool Storage::Equals( const BaseStorage& rStorage ) const
+{
+    const Storage* pOther =  dynamic_cast<const Storage*>( &rStorage );
+    return pOther && ( pOther->pEntry == pEntry );
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/sot/source/sdstor/stgavl.cxx b/sot/source/sdstor/stgavl.cxx
new file mode 100644
index 000000000..98a86f3ed
--- /dev/null
+++ b/sot/source/sdstor/stgavl.cxx
@@ -0,0 +1,411 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+#include <osl/diagnose.h>
+#include "stgavl.hxx"
+#include <assert.h>
+
+StgAvlNode::StgAvlNode()
+{
+    m_pLeft = m_pRight = nullptr;
+    m_nBalance = m_nId = 0;
+}
+
+StgAvlNode::~StgAvlNode()
+{
+    delete m_pLeft;
+    delete m_pRight;
+}
+
+StgAvlNode* StgAvlNode::Find( StgAvlNode const * pFind )
+{
+    if ( pFind )
+    {
+        StgAvlNode* p = this;
+        while( p )
+        {
+            sal_Int32 nRes = p->Compare( pFind );
+            if( !nRes )
+                return p;
+            else p = ( nRes < 0 ) ? p->m_pLeft : p->m_pRight;
+        }
+    }
+    return nullptr;
+}
+
+// find point to add node to AVL tree and returns
+// +/0/- for >/=/< previous
+
+sal_Int32 StgAvlNode::Locate
+    ( StgAvlNode const * pFind,
+      StgAvlNode** pPivot, StgAvlNode **pParent, StgAvlNode** pPrev )
+{
+    sal_Int32 nRes = 0;
+    StgAvlNode* pCur = this;
+
+    OSL_ENSURE( pPivot && pParent && pPrev, "The pointers may not be NULL!" );
+    *pParent = *pPrev = nullptr;
+    *pPivot = this;
+
+    // search tree for insertion point
+    if ( pFind )
+    {
+        while( pCur != nullptr )
+        {
+            // check for pPivot
+            if( pCur->m_nBalance != 0 )
+            {
+                *pPivot = pCur;
+                *pParent = *pPrev;
+            }
+            // save pPrev location and see what direction to go
+            *pPrev = pCur;
+            nRes = pCur->Compare( pFind );
+            if( nRes == 0 )
+                break;
+            else pCur = ( nRes < 0 ) ? pCur->m_pLeft : pCur->m_pRight;
+        }
+    }
+
+    return nRes;
+}
+
+// adjust balance factors in AVL tree from pivot down.
+// Returns delta balance.
+
+short StgAvlNode::Adjust( StgAvlNode** pHeavy, StgAvlNode const * pNew )
+{
+    StgAvlNode* pCur = this;
+    short nDelta;
+    // no traversing
+    OSL_ENSURE( pHeavy && pNew, "The pointers is not allowed to be NULL!" );
+    if( pCur == pNew || !pNew )
+        return m_nBalance;
+
+    sal_Int32 nRes = Compare( pNew );
+    if( nRes > 0 )
+    {
+        *pHeavy = pCur = m_pRight;
+        nDelta = -1;
+    }
+    else
+    {
+        *pHeavy = pCur = m_pLeft;
+        nDelta = 1;
+    }
+    m_nBalance = 0;
+    while( pCur != pNew )
+    {
+        nRes = pCur->Compare( pNew );
+        if( nRes > 0 )
+        {
+            // height of right increases by 1
+            pCur->m_nBalance = -1;
+            pCur = pCur->m_pRight;
+        }
+        else
+        {
+            // height of left increases by 1
+            pCur->m_nBalance = 1;
+            pCur = pCur->m_pLeft;
+        }
+    }
+    m_nBalance = m_nBalance + nDelta;
+    return nDelta;
+}
+
+// perform LL rotation and return new root
+
+StgAvlNode* StgAvlNode::RotLL()
+{
+    assert(m_pLeft && "The pointer is not allowed to be NULL!");
+    StgAvlNode *pHeavy = m_pLeft;
+    m_pLeft = pHeavy->m_pRight;
+    pHeavy->m_pRight = this;
+    pHeavy->m_nBalance = m_nBalance = 0;
+    return pHeavy;
+}
+
+// perform LR rotation and return new root
+
+StgAvlNode* StgAvlNode::RotLR()
+{
+    assert(m_pLeft && m_pLeft->m_pRight && "The pointer is not allowed to be NULL!");
+    StgAvlNode* pHeavy = m_pLeft;
+    StgAvlNode* pNewRoot = pHeavy->m_pRight;
+
+    pHeavy->m_pRight = pNewRoot->m_pLeft;
+    m_pLeft = pNewRoot->m_pRight;
+    pNewRoot->m_pLeft = pHeavy;
+    pNewRoot->m_pRight = this;
+
+    switch( pNewRoot->m_nBalance )
+    {
+        case 1:     // LR( b )
+            m_nBalance = -1;
+            pHeavy->m_nBalance = 0;
+            break;
+        case -1:    // LR( c )
+            pHeavy->m_nBalance = 1;
+            m_nBalance = 0;
+            break;
+        case 0:     // LR( a )
+            m_nBalance = 0;
+            pHeavy->m_nBalance = 0;
+            break;
+    }
+    pNewRoot->m_nBalance = 0;
+    return pNewRoot;
+}
+
+// perform RR rotation and return new root
+StgAvlNode* StgAvlNode::RotRR()
+{
+    assert(m_pRight && "The pointer is not allowed to be NULL!" );
+    StgAvlNode* pHeavy = m_pRight;
+    m_pRight = pHeavy->m_pLeft;
+    pHeavy->m_pLeft = this;
+    m_nBalance = pHeavy->m_nBalance = 0;
+    return pHeavy;
+}
+
+// perform the RL rotation and return the new root
+StgAvlNode* StgAvlNode::RotRL()
+{
+    assert(m_pRight && m_pRight->m_pLeft && "The pointer is not allowed to be NULL!");
+    StgAvlNode* pHeavy = m_pRight;
+    StgAvlNode* pNewRoot = pHeavy->m_pLeft;
+    pHeavy->m_pLeft = pNewRoot->m_pRight;
+    m_pRight = pNewRoot->m_pLeft;
+    pNewRoot->m_pRight = pHeavy;
+    pNewRoot->m_pLeft = this;
+    switch( pNewRoot->m_nBalance )
+    {
+        case -1:    // RL( b )
+            m_nBalance = 1;
+            pHeavy->m_nBalance = 0;
+            break;
+        case 1:     // RL( c )
+            pHeavy->m_nBalance = -1;
+            m_nBalance = 0;
+            break;
+        case 0:     // RL( a )
+            m_nBalance = 0;
+            pHeavy->m_nBalance = 0;
+            break;
+    }
+    pNewRoot->m_nBalance = 0;
+    return pNewRoot;
+}
+
+// Remove a tree element. Return the removed element or NULL.
+
+StgAvlNode* StgAvlNode::Rem( StgAvlNode** p, StgAvlNode* pDel, bool bPtrs )
+{
+    if( p && *p && pDel )
+    {
+        StgAvlNode* pCur = *p;
+        sal_Int32 nRes = bPtrs ? sal_Int32( pCur == pDel ) : pCur->Compare( pDel );
+        if( !nRes )
+        {
+            // Element found: remove
+            if( !pCur->m_pRight )
+            {
+                *p = pCur->m_pLeft; pCur->m_pLeft = nullptr;
+            }
+            else if( !pCur->m_pLeft )
+            {
+                *p = pCur->m_pRight; pCur->m_pRight = nullptr;
+            }
+            else
+            {
+                // The damn element has two leaves. Get the
+                // rightmost element of the left subtree (which
+                // is lexically before this element) and replace
+                // this element with the element found.
+                StgAvlNode* last = pCur;
+                StgAvlNode* l;
+                for( l = pCur->m_pLeft;
+                     l->m_pRight; last = l, l = l->m_pRight ) {}
+                // remove the element from chain
+                if( l == last->m_pRight )
+                    last->m_pRight = l->m_pLeft;
+                else
+                    last->m_pLeft = l->m_pLeft;
+                // perform the replacement
+                l->m_pLeft = pCur->m_pLeft;
+                l->m_pRight = pCur->m_pRight;
+                *p = l;
+                // delete the element
+                pCur->m_pLeft = pCur->m_pRight = nullptr;
+            }
+            return pCur;
+        }
+        else
+        {
+            if( nRes < 0 )
+                return Rem( &pCur->m_pLeft, pDel, bPtrs );
+            else
+                return Rem( &pCur->m_pRight, pDel, bPtrs );
+        }
+    }
+    return nullptr;
+}
+
+// Enumerate the tree for later iteration
+
+void StgAvlNode::StgEnum( short& n )
+{
+    if( m_pLeft )
+        m_pLeft->StgEnum( n );
+    m_nId = n++;
+    if( m_pRight )
+        m_pRight->StgEnum( n );
+}
+
+// Add node to AVL tree.
+// Return false if the element already exists.
+
+bool StgAvlNode::Insert( StgAvlNode** pRoot, StgAvlNode* pIns )
+{
+    StgAvlNode* pPivot, *pHeavy, *pParent, *pPrev;
+    if ( !pRoot )
+        return false;
+
+    // special case - empty tree
+    if( *pRoot == nullptr )
+    {
+        *pRoot = pIns;
+        return true;
+    }
+    // find insertion point and return if already present
+    sal_Int32 nRes = (*pRoot)->Locate( pIns, &pPivot, &pParent, &pPrev );
+    if( !nRes )
+        return false;
+
+    assert(pPivot && pPrev && "The pointers may not be NULL!");
+
+    // add new node
+    if( nRes < 0 )
+        pPrev->m_pLeft = pIns;
+    else
+        pPrev->m_pRight = pIns;
+    // rebalance tree
+    short nDelta = pPivot->Adjust( &pHeavy, pIns );
+    if( pPivot->m_nBalance >= 2 || pPivot->m_nBalance <= -2 )
+    {
+        StgAvlNode* pNewRoot;
+        pHeavy = ( nDelta < 0 ) ? pPivot->m_pRight : pPivot->m_pLeft;
+        // left imbalance
+        if( nDelta > 0 )
+            if( pHeavy->m_nBalance == 1 )
+                pNewRoot = pPivot->RotLL();
+            else
+                pNewRoot = pPivot->RotLR();
+        // right imbalance
+        else if( pHeavy->m_nBalance == -1 )
+            pNewRoot = pPivot->RotRR();
+        else
+            pNewRoot = pPivot->RotRL();
+        // relink balanced subtree
+        if( pParent == nullptr )
+            *pRoot = pNewRoot;
+        else if( pPivot == pParent->m_pLeft )
+            pParent->m_pLeft = pNewRoot;
+        else if( pPivot == pParent->m_pRight )
+            pParent->m_pRight = pNewRoot;
+    }
+    return true;
+}
+
+// Remove node from tree. Returns true is found and removed.
+// Actually delete if bDel
+
+bool StgAvlNode::Remove( StgAvlNode** pRoot, StgAvlNode* pDel, bool bDel )
+{
+    if ( !pRoot )
+        return false;
+
+    // special case - empty tree
+    if( *pRoot == nullptr )
+        return false;
+    // delete the element
+    pDel = Rem( pRoot, pDel, false );
+    if( pDel )
+    {
+        if( bDel )
+            delete pDel;
+        // Rebalance the tree the hard way
+        // OS 22.09.95: On MD's request commented out due to crash
+/*      StgAvlNode* pNew = NULL;
+        while( *pRoot )
+        {
+            StgAvlNode* p = Rem( pRoot, *pRoot, false );
+            Insert( &pNew, p );
+        }
+        *pRoot = pNew;*/
+        return true;
+    }
+    else
+        return false;
+}
+
+// Move node to a different tree. Returns true is found and moved. This routine
+// may be called when the key has changed.
+
+
+////////////////////////// class AvlIterator
+
+// The iterator walks through a tree one entry by one.
+
+StgAvlIterator::StgAvlIterator( StgAvlNode* p )
+{
+    m_pRoot = p;
+    m_nCur = 0;
+    if( p )
+    {
+        short nCount = 0; // tree size
+        p->StgEnum( nCount );
+    }
+}
+
+StgAvlNode* StgAvlIterator::Find( short n )
+{
+    StgAvlNode* p = m_pRoot;
+    while( p )
+    {
+        if( n == p->m_nId )
+            break;
+        else p = ( n < p->m_nId ) ? p->m_pLeft : p->m_pRight;
+    }
+    return p;
+}
+
+StgAvlNode* StgAvlIterator::First()
+{
+    m_nCur = -1;
+    return Next();
+}
+
+StgAvlNode* StgAvlIterator::Next()
+{
+    return Find( ++m_nCur );
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/sot/source/sdstor/stgavl.hxx b/sot/source/sdstor/stgavl.hxx
new file mode 100644
index 000000000..c78df1722
--- /dev/null
+++ b/sot/source/sdstor/stgavl.hxx
@@ -0,0 +1,67 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+#ifndef INCLUDED_SOT_SOURCE_SDSTOR_STGAVL_HXX
+#define INCLUDED_SOT_SOURCE_SDSTOR_STGAVL_HXX
+
+#include <sal/types.h>
+
+// This is an abstract base class for nodes.
+// Especially, the compare function must be implemented.
+
+class StgAvlNode
+{
+    friend class StgAvlIterator;
+private:
+    sal_Int32 Locate( StgAvlNode const *, StgAvlNode**, StgAvlNode**, StgAvlNode** );
+    short Adjust( StgAvlNode**, StgAvlNode const * );
+    StgAvlNode* RotLL();
+    StgAvlNode* RotLR();
+    StgAvlNode* RotRR();
+    StgAvlNode* RotRL();
+    void   StgEnum( short& );
+    static StgAvlNode* Rem( StgAvlNode**, StgAvlNode*, bool );
+protected:
+    short m_nId;                          // iterator ID
+    short m_nBalance;                     // indicates tree balance
+    StgAvlNode* m_pLeft, *m_pRight;         // leaves
+    StgAvlNode();
+public:
+    virtual ~StgAvlNode();
+    StgAvlNode* Find( StgAvlNode const * );
+    static bool Insert( StgAvlNode**, StgAvlNode* );
+    static bool Remove( StgAvlNode**, StgAvlNode*, bool bDel );
+    virtual sal_Int32 Compare( const StgAvlNode* ) const = 0;
+};
+
+// The iterator class provides single stepping through an AVL tree.
+
+class StgAvlIterator {
+    StgAvlNode* m_pRoot;                  // root entry (parent)
+    short       m_nCur;                   // current element
+    StgAvlNode* Find( short );
+public:
+    explicit StgAvlIterator( StgAvlNode* );
+    StgAvlNode* First();
+    StgAvlNode* Next();
+};
+
+#endif
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/sot/source/sdstor/stgcache.cxx b/sot/source/sdstor/stgcache.cxx
new file mode 100644
index 000000000..93f7d3090
--- /dev/null
+++ b/sot/source/sdstor/stgcache.cxx
@@ -0,0 +1,430 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+#include <string.h>
+#include <o3tl/safeint.hxx>
+#include <osl/endian.h>
+#include <osl/diagnose.h>
+
+#include <sot/stg.hxx>
+#include "stgcache.hxx"
+
+#include <algorithm>
+
+////////////////////////////// class StgPage
+// This class implements buffer functionality. The cache will always return
+// a page buffer, even if a read fails. It is up to the caller to determine
+// the correctness of the I/O.
+
+StgPage::StgPage( short nSize, sal_Int32 nPage )
+    : mnPage( nPage )
+    , mpData( new sal_uInt8[ nSize ] )
+    , mnSize( nSize )
+{
+    OSL_ENSURE( mnSize >= 512, "Unexpected page size is provided!" );
+    // We will write this data to a permanent file later
+    // best to clear if first.
+    memset( mpData.get(), 0, mnSize );
+}
+
+StgPage::~StgPage()
+{
+}
+
+rtl::Reference< StgPage > StgPage::Create( short nData, sal_Int32 nPage )
+{
+    return rtl::Reference< StgPage >( new StgPage( nData, nPage ) );
+}
+
+void StgCache::SetToPage ( const rtl::Reference< StgPage >& rPage, short nOff, sal_Int32 nVal )
+{
+    if( nOff >= 0 && ( o3tl::make_unsigned(nOff) < rPage->GetSize() / sizeof( sal_Int32 ) ) )
+    {
+#ifdef OSL_BIGENDIAN
+        nVal = OSL_SWAPDWORD(nVal);
+#endif
+        static_cast<sal_Int32*>(rPage->GetData())[ nOff ] = nVal;
+        SetDirty( rPage );
+    }
+}
+
+bool StgPage::IsPageGreater( const StgPage *pA, const StgPage *pB )
+{
+    return pA->mnPage < pB->mnPage;
+}
+
+//////////////////////////////// class StgCache
+
+// The disk cache holds the cached sectors. The sector type differ according
+// to their purpose.
+
+static sal_Int32 lcl_GetPageCount( sal_uInt64 nFileSize, short nPageSize )
+{
+//    return (nFileSize >= 512) ? (nFileSize - 512) / nPageSize : 0;
+    // #i61980# real life: last page may be incomplete, return number of *started* pages
+    return (nFileSize >= 512) ? (nFileSize - 512 + nPageSize - 1) / nPageSize : 0;
+}
+
+StgCache::StgCache()
+   : m_nError( ERRCODE_NONE )
+   , m_nPages( 0 )
+   , m_nRef( 0 )
+   , m_nReplaceIdx( 0 )
+   , maLRUPages( 8 ) // entries in the LRU lookup
+   , m_nPageSize( 512 )
+   , m_pStorageStream( nullptr )
+   , m_pStrm( nullptr )
+   , m_bMyStream( false )
+   , m_bFile( false )
+{
+}
+
+StgCache::~StgCache()
+{
+    Clear();
+    SetStrm( nullptr, false );
+}
+
+void StgCache::SetPhysPageSize( short n )
+{
+    OSL_ENSURE( n >= 512, "Unexpected page size is provided!" );
+    if ( n >= 512 )
+    {
+        m_nPageSize = n;
+        sal_uInt64 nFileSize = m_pStrm->TellEnd();
+        m_nPages = lcl_GetPageCount( nFileSize, m_nPageSize );
+    }
+}
+
+// Create a new cache element
+
+rtl::Reference< StgPage > StgCache::Create( sal_Int32 nPg )
+{
+    rtl::Reference< StgPage > xElem( StgPage::Create( m_nPageSize, nPg ) );
+    maLRUPages[ m_nReplaceIdx++ % maLRUPages.size() ] = xElem;
+    return xElem;
+}
+
+// Delete the given element
+
+void StgCache::Erase( const rtl::Reference< StgPage > &xElem )
+{
+    OSL_ENSURE( xElem.is(), "The pointer should not be NULL!" );
+    if ( xElem.is() ) {
+        auto it = std::find_if(maLRUPages.begin(), maLRUPages.end(),
+            [xElem](const rtl::Reference<StgPage>& rxPage) { return rxPage.is() && rxPage->GetPage() == xElem->GetPage(); });
+        if (it != maLRUPages.end())
+            it->clear();
+    }
+}
+
+// remove all cache elements without flushing them
+
+void StgCache::Clear()
+{
+    maDirtyPages.clear();
+    for (auto& rxPage : maLRUPages)
+        rxPage.clear();
+}
+
+// Look for a cached page
+
+rtl::Reference< StgPage > StgCache::Find( sal_Int32 nPage )
+{
+    auto it = std::find_if(maLRUPages.begin(), maLRUPages.end(),
+        [nPage](const rtl::Reference<StgPage>& rxPage) { return rxPage.is() && rxPage->GetPage() == nPage; });
+    if (it != maLRUPages.end())
+        return *it;
+    IndexToStgPage::iterator it2 = maDirtyPages.find( nPage );
+    if ( it2 != maDirtyPages.end() )
+        return it2->second;
+    return rtl::Reference< StgPage >();
+}
+
+// Load a page into the cache
+
+rtl::Reference< StgPage > StgCache::Get( sal_Int32 nPage, bool bForce )
+{
+    rtl::Reference< StgPage > p = Find( nPage );
+    if( !p.is() )
+    {
+        p = Create( nPage );
+        if( !Read( nPage, p->GetData() ) && bForce )
+        {
+            Erase( p );
+            p.clear();
+            SetError( SVSTREAM_READ_ERROR );
+        }
+    }
+    return p;
+}
+
+// Copy an existing page into a new page. Use this routine
+// to duplicate an existing stream or to create new entries.
+// The new page is initially marked dirty. No owner is copied.
+
+rtl::Reference< StgPage > StgCache::Copy( sal_Int32 nNew, sal_Int32 nOld )
+{
+    rtl::Reference< StgPage > p = Find( nNew );
+    if( !p.is() )
+        p = Create( nNew );
+    if( nOld >= 0 )
+    {
+        // old page: we must have this data!
+        rtl::Reference< StgPage > q = Get( nOld, true );
+        if( q.is() )
+        {
+            OSL_ENSURE( p->GetSize() == q->GetSize(), "Unexpected page size!" );
+            memcpy( p->GetData(), q->GetData(), p->GetSize() );
+        }
+    }
+    SetDirty( p );
+
+    return p;
+}
+
+// Historically this wrote pages in a sorted, ascending order;
+// continue that tradition.
+bool StgCache::Commit()
+{
+    if ( Good() ) // otherwise Write does nothing
+    {
+        std::vector< StgPage * > aToWrite;
+        aToWrite.reserve(maDirtyPages.size());
+        for (const auto& rEntry : maDirtyPages)
+            aToWrite.push_back( rEntry.second.get() );
+
+        std::sort( aToWrite.begin(), aToWrite.end(), StgPage::IsPageGreater );
+        for (StgPage* pWr : aToWrite)
+        {
+            const rtl::Reference< StgPage > &pPage = pWr;
+            if ( !Write( pPage->GetPage(), pPage->GetData() ) )
+                return false;
+        }
+    }
+
+    maDirtyPages.clear();
+
+    m_pStrm->Flush();
+    SetError( m_pStrm->GetError() );
+
+    return true;
+}
+
+// Set a stream
+
+void StgCache::SetStrm( SvStream* p, bool bMy )
+{
+    if( m_pStorageStream )
+    {
+        m_pStorageStream->ReleaseRef();
+        m_pStorageStream = nullptr;
+    }
+
+    if( m_bMyStream )
+        delete m_pStrm;
+    m_pStrm = p;
+    m_bMyStream = bMy;
+}
+
+void StgCache::SetStrm( UCBStorageStream* pStgStream )
+{
+    if( m_pStorageStream )
+        m_pStorageStream->ReleaseRef();
+    m_pStorageStream = pStgStream;
+
+    if( m_bMyStream )
+        delete m_pStrm;
+
+    m_pStrm = nullptr;
+
+    if ( m_pStorageStream )
+    {
+        m_pStorageStream->AddFirstRef();
+        m_pStrm = m_pStorageStream->GetModifySvStream();
+    }
+
+    m_bMyStream = false;
+}
+
+void StgCache::SetDirty( const rtl::Reference< StgPage > &rPage )
+{
+    assert( m_pStrm && m_pStrm->IsWritable() );
+    maDirtyPages[ rPage->GetPage() ] = rPage;
+}
+
+// Open/close the disk file
+
+bool StgCache::Open( const OUString& rName, StreamMode nMode )
+{
+    // do not open in exclusive mode!
+    if( nMode & StreamMode::SHARE_DENYALL )
+        nMode = ( ( nMode & ~StreamMode::SHARE_DENYALL ) | StreamMode::SHARE_DENYWRITE );
+    SvFileStream* pFileStrm = new SvFileStream( rName, nMode );
+    // SvStream "feature" Write Open also successful if it does not work
+    bool bAccessDenied = false;
+    if( ( nMode & StreamMode::WRITE ) && !pFileStrm->IsWritable() )
+    {
+        pFileStrm->Close();
+        bAccessDenied = true;
+    }
+    SetStrm( pFileStrm, true );
+    if( pFileStrm->IsOpen() )
+    {
+        sal_uInt64 nFileSize = m_pStrm->TellEnd();
+        m_nPages = lcl_GetPageCount( nFileSize, m_nPageSize );
+        m_pStrm->Seek( 0 );
+    }
+    else
+        m_nPages = 0;
+    m_bFile = true;
+    SetError( bAccessDenied ? ERRCODE_IO_ACCESSDENIED : m_pStrm->GetError() );
+    return Good();
+}
+
+void StgCache::Close()
+{
+    if( m_bFile )
+    {
+        static_cast<SvFileStream*>(m_pStrm)->Close();
+        SetError( m_pStrm->GetError() );
+    }
+}
+
+// low level I/O
+
+bool StgCache::Read( sal_Int32 nPage, void* pBuf )
+{
+    sal_uInt32 nRead = 0, nBytes = m_nPageSize;
+    if( Good() )
+    {
+        /*  #i73846# real life: a storage may refer to a page one-behind the
+            last valid page (see document attached to the issue). In that case
+            (if nPage==nPages), just do nothing here and let the caller work on
+            the empty zero-filled buffer. */
+        if ( nPage > m_nPages )
+            SetError( SVSTREAM_READ_ERROR );
+        else if ( nPage < m_nPages )
+        {
+            sal_uInt32 nPos;
+            sal_Int32 nPg2;
+            // fixed address and size for the header
+            if( nPage == -1 )
+            {
+                nPos = 0;
+                nPg2 = 1;
+                nBytes = 512;
+            }
+            else
+            {
+                nPos = Page2Pos(nPage);
+                nPg2 = ((nPage + 1) > m_nPages) ? m_nPages - nPage : 1;
+            }
+
+            if (m_pStrm->Tell() != nPos)
+                m_pStrm->Seek(nPos);
+
+            if (nPg2 != 1)
+                SetError(SVSTREAM_READ_ERROR);
+            else
+            {
+                nRead = m_pStrm->ReadBytes(pBuf, nBytes);
+                SetError(m_pStrm->GetError());
+            }
+        }
+    }
+
+    if (!Good())
+        return false;
+
+    if (nRead != nBytes)
+        memset(static_cast<sal_uInt8*>(pBuf) + nRead, 0, nBytes - nRead);
+    return true;
+}
+
+bool StgCache::Write( sal_Int32 nPage, void const * pBuf )
+{
+    if( Good() )
+    {
+        sal_uInt32 nPos = Page2Pos( nPage );
+        sal_uInt32 nBytes = m_nPageSize;
+
+        // fixed address and size for the header
+        // nPageSize must be >= 512, otherwise the header can not be written here, we check it on import
+        if( nPage == -1 )
+        {
+            nPos = 0;
+            nBytes = 512;
+        }
+        if( m_pStrm->Tell() != nPos )
+        {
+            m_pStrm->Seek(nPos);
+        }
+        size_t nRes = m_pStrm->WriteBytes( pBuf, nBytes );
+        if( nRes != nBytes )
+            SetError( SVSTREAM_WRITE_ERROR );
+        else
+            SetError( m_pStrm->GetError() );
+    }
+    return Good();
+}
+
+// set the file size in pages
+
+bool StgCache::SetSize( sal_Int32 n )
+{
+    // Add the file header
+    sal_Int32 nSize = n * m_nPageSize + 512;
+    m_pStrm->SetStreamSize( nSize );
+    SetError( m_pStrm->GetError() );
+    if( !m_nError )
+        m_nPages = n;
+    return Good();
+}
+
+void StgCache::SetError( ErrCode n )
+{
+    if( n && !m_nError )
+        m_nError = n;
+}
+
+void StgCache::ResetError()
+{
+    m_nError = ERRCODE_NONE;
+    m_pStrm->ResetError();
+}
+
+void StgCache::MoveError( StorageBase const & r )
+{
+    if( m_nError != ERRCODE_NONE )
+    {
+        r.SetError( m_nError );
+        ResetError();
+    }
+}
+
+// Utility functions
+
+sal_Int32 StgCache::Page2Pos( sal_Int32 nPage ) const
+{
+    if( nPage < 0 ) nPage = 0;
+    return( nPage * m_nPageSize ) + m_nPageSize;
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/sot/source/sdstor/stgcache.hxx b/sot/source/sdstor/stgcache.hxx
new file mode 100644
index 000000000..7efbffae5
--- /dev/null
+++ b/sot/source/sdstor/stgcache.hxx
@@ -0,0 +1,131 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+#ifndef INCLUDED_SOT_SOURCE_SDSTOR_STGCACHE_HXX
+#define INCLUDED_SOT_SOURCE_SDSTOR_STGCACHE_HXX
+
+#include <o3tl/safeint.hxx>
+#include <osl/endian.h>
+#include <rtl/ref.hxx>
+#include <tools/stream.hxx>
+#include "stgelem.hxx"
+#include <salhelper/simplereferenceobject.hxx>
+
+#include <memory>
+#include <unordered_map>
+
+class UCBStorageStream;
+class StgPage;
+class StorageBase;
+
+class StgCache
+{
+    typedef std::unordered_map
+    <
+        sal_Int32, rtl::Reference< StgPage >
+    > IndexToStgPage;
+
+    typedef std::vector< rtl::Reference< StgPage > > LRUList;
+
+    ErrCode m_nError;                         // error code
+    sal_Int32 m_nPages;                       // size of data area in pages
+    sal_uInt16 m_nRef;                        // reference count
+    IndexToStgPage maDirtyPages;            // hash of all dirty pages
+    int     m_nReplaceIdx;                    // index into maLRUPages to replace next
+    LRUList maLRUPages;                     // list of last few non-dirty pages.
+    short m_nPageSize;                        // page size of the file
+    UCBStorageStream* m_pStorageStream;       // holds reference to UCB storage stream
+
+    void Erase( const rtl::Reference< StgPage >& ); // delete a cache element
+    rtl::Reference< StgPage > Create( sal_Int32  ); // create a cached page
+    SvStream* m_pStrm;                        // physical stream
+    bool  m_bMyStream;                        // true: delete stream in dtor
+protected:
+    bool  m_bFile;                            // true: file stream
+    sal_Int32 Page2Pos( sal_Int32 ) const;    // page address --> file position
+public:
+    StgCache();
+    ~StgCache();
+    void  IncRef()                          { m_nRef++;           }
+    sal_uInt16 DecRef()                     { return --m_nRef;    }
+    void  SetPhysPageSize( short );
+    sal_Int32 GetPhysPages() const          { return m_nPages;    }
+    short GetPhysPageSize() const           { return m_nPageSize; }
+    SvStream* GetStrm()                     { return m_pStrm;     }
+    void  SetStrm( SvStream*, bool );
+    void  SetStrm( UCBStorageStream* );
+    bool  Good() const                      { return m_nError == ERRCODE_NONE; }
+    ErrCode const & GetError() const        { return m_nError;    }
+    void  MoveError( StorageBase const & );
+    void  SetError( ErrCode );
+    void  ResetError();
+    bool  Open( const OUString& rName, StreamMode );
+    void  Close();
+    bool  Read( sal_Int32 nPage, void* pBuf );
+    bool  Write( sal_Int32 nPage, void const * pBuf );
+
+    // two routines for accessing FAT pages
+    // Assume that the data is a FAT page and get/put FAT data.
+    void  SetToPage   ( const rtl::Reference< StgPage >& rPage, short nOff, sal_Int32 nVal );
+    static inline sal_Int32 GetFromPage ( const rtl::Reference< StgPage >& rPage, short nOff );
+    void  SetDirty    ( const rtl::Reference< StgPage > &rPage );
+    bool  SetSize( sal_Int32 nPages );
+    rtl::Reference< StgPage > Find( sal_Int32 );                 // find a cached page
+    rtl::Reference< StgPage > Get( sal_Int32, bool );            // get a cached page
+    rtl::Reference< StgPage > Copy( sal_Int32, sal_Int32=STG_FREE ); // copy a page
+    bool Commit(); // flush all pages
+    void Clear();                           // clear the cache
+};
+
+class StgPage : public salhelper::SimpleReferenceObject
+{
+    const sal_Int32 mnPage;                // page index
+    std::unique_ptr<sal_uInt8[]>
+                    mpData;                // nSize bytes
+    short           mnSize;                // size of this page
+             StgPage( short nData, sal_Int32 nPage );
+    virtual ~StgPage() override;
+public:
+             StgPage(const StgPage&) = delete;
+    StgPage& operator=(const StgPage&) = delete;
+    static rtl::Reference< StgPage > Create( short nData, sal_Int32 nPage );
+
+    sal_Int32 GetPage() const { return mnPage; }
+    void*     GetData()  { return mpData.get(); }
+    short     GetSize() const { return mnSize; }
+
+public:
+    static bool IsPageGreater( const StgPage *pA, const StgPage *pB );
+};
+
+inline sal_Int32 StgCache::GetFromPage ( const rtl::Reference< StgPage >& rPage, short nOff )
+{
+    if( nOff < 0 || ( o3tl::make_unsigned(nOff) >= rPage->GetSize() / sizeof( sal_Int32 ) ) )
+        return -1;
+    sal_Int32 n = static_cast<sal_Int32*>(rPage->GetData())[ nOff ];
+#ifdef OSL_BIGENDIAN
+    return OSL_SWAPDWORD(n);
+#else
+    return n;
+#endif
+}
+
+#endif
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/sot/source/sdstor/stgdir.cxx b/sot/source/sdstor/stgdir.cxx
new file mode 100644
index 000000000..69ca094f3
--- /dev/null
+++ b/sot/source/sdstor/stgdir.cxx
@@ -0,0 +1,938 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+
+#include <sot/stg.hxx>
+#include "stgelem.hxx"
+#include "stgstrms.hxx"
+#include "stgdir.hxx"
+#include "stgio.hxx"
+
+#include <osl/diagnose.h>
+#include <sal/log.hxx>
+
+#include <memory>
+
+//////////////////////////// class StgDirEntry
+
+// This class holds the dir entry data and maintains dirty flags for both
+// the entry and the data.
+
+// Transacted mode for streams: On the first write, a temp stream pTmpStrm
+// is created and operated on. A commit moves pTmpStrm to pCurStrm, which
+// is used for subsequent reads. A new write creates a new copy of pTmpStrm
+// based on pCurStrm. Reverting throws away pTmpStrm.
+// Transacted mode for storages: A copy of the dir ents is kept in aSave.
+// Committing means copying aEntry to aSave. Reverting means to copy aSave
+// to aEntry, delete newly created entries and to reactivate removed entries.
+
+// Problem of implementation: No hierarchical commits. Therefore only
+// overall transaction-oriented or direct.
+
+StgDirEntry::StgDirEntry( const void* pBuffer, sal_uInt32 nBufferLen, sal_uInt64 nUnderlyingStreamSize, bool * pbOk )
+{
+    *pbOk = m_aEntry.Load( pBuffer, nBufferLen, nUnderlyingStreamSize );
+
+    InitMembers();
+}
+
+StgDirEntry::StgDirEntry( const StgEntry& r ) :  m_aEntry( r )
+{
+    InitMembers();
+}
+
+// Helper for all ctors
+
+void StgDirEntry::InitMembers()
+{
+    m_aSave       = m_aEntry;
+    m_pUp         =
+    m_pDown       = nullptr;
+    m_pStgStrm    = nullptr;
+    m_pCurStrm    =
+    m_pTmpStrm    = nullptr;
+    m_nPos        =
+    m_nEntry      =
+    m_nRefCnt     = 0;
+    m_nMode       = StreamMode::READ;
+    m_bDirect     = true;
+    m_bInvalid    =
+    m_bRemoved    =
+    m_bTemp       =
+    m_bDirty      =
+    m_bZombie     = false;
+}
+
+StgDirEntry::~StgDirEntry()
+{
+    Close();
+    delete m_pCurStrm;
+    delete m_pStgStrm;
+    delete m_pDown;
+}
+
+// Comparison function
+
+sal_Int32 StgDirEntry::Compare( const StgAvlNode* p ) const
+{
+    sal_Int32 nResult = -1;
+    if ( p )
+    {
+        const StgDirEntry* pEntry = static_cast<const StgDirEntry*>(p);
+        nResult = m_aEntry.Compare( pEntry->m_aEntry );
+    }
+    return nResult;
+}
+
+// Enumerate the entry numbers.
+// n is incremented to show the total # of entries.
+// These number are later used as page numbers when storing
+// the TOC tree into the TOC stream. Remember that aSave is
+// stored, not aEntry.
+
+void StgDirEntry::Enum( sal_Int32& n )
+{
+    sal_Int32 nLeft = STG_FREE, nRight = STG_FREE, nDown = STG_FREE;
+    m_nEntry = n++;
+    if( m_pLeft )
+    {
+        static_cast<StgDirEntry*>(m_pLeft)->Enum( n );
+        nLeft = static_cast<StgDirEntry*>(m_pLeft)->m_nEntry;
+    }
+    if( m_pRight )
+    {
+        static_cast<StgDirEntry*>(m_pRight)->Enum( n );
+        nRight = static_cast<StgDirEntry*>(m_pRight)->m_nEntry;
+    }
+    if( m_pDown )
+    {
+        m_pDown->Enum( n ); nDown = m_pDown->m_nEntry;
+    }
+    m_aSave.SetLeaf( STG_LEFT, nLeft );
+    m_aSave.SetLeaf( STG_RIGHT, nRight );
+    m_aSave.SetLeaf( STG_CHILD, nDown );
+}
+
+// Delete all temporary entries before writing the TOC stream.
+// Until now Deltemp is never called with bForce True
+
+void StgDirEntry::DelTemp( bool bForce )
+{
+    if( m_pLeft )
+        static_cast<StgDirEntry*>(m_pLeft)->DelTemp( false );
+    if( m_pRight )
+        static_cast<StgDirEntry*>(m_pRight)->DelTemp( false );
+    if( m_pDown )
+    {
+        // If the storage is dead, of course all elements are dead, too
+        if( m_bInvalid && m_aEntry.GetType() == STG_STORAGE )
+            bForce = true;
+        m_pDown->DelTemp( bForce );
+    }
+    if( !( bForce || m_bInvalid ) || ( m_aEntry.GetType() == STG_ROOT ) )
+        return;
+
+    Close();
+    if( m_pUp )
+    {
+        // this deletes the element if refcnt == 0!
+        bool bDel = m_nRefCnt == 0;
+        StgAvlNode::Remove( reinterpret_cast<StgAvlNode**>(&m_pUp->m_pDown), this, bDel );
+        if( !bDel )
+        {
+            m_pLeft = m_pRight = m_pDown = nullptr;
+            m_bInvalid = m_bZombie = true;
+        }
+    }
+}
+
+// Save the tree into the given dir stream
+
+bool StgDirEntry::Store( StgDirStrm& rStrm )
+{
+    void* pEntry = rStrm.GetEntry( m_nEntry, true );
+    if( !pEntry )
+        return false;
+    // Do not store the current (maybe not committed) entry
+    m_aSave.Store( pEntry );
+    if( m_pLeft )
+        if( !static_cast<StgDirEntry*>(m_pLeft)->Store( rStrm ) )
+            return false;
+    if( m_pRight )
+        if( !static_cast<StgDirEntry*>(m_pRight)->Store( rStrm ) )
+            return false;
+    if( m_pDown && !m_pDown->Store( rStrm ) )
+        return false;
+    return true;
+}
+
+bool StgDirEntry::StoreStream( StgIo& rIo )
+{
+    if( m_aEntry.GetType() == STG_STREAM || m_aEntry.GetType() == STG_ROOT )
+    {
+        if( m_bInvalid )
+        {
+            // Delete the stream if needed
+            if( !m_pStgStrm )
+            {
+                OpenStream( rIo );
+                delete m_pStgStrm;
+                m_pStgStrm = nullptr;
+            }
+            else
+                m_pStgStrm->SetSize( 0 );
+        }
+        // or write the data stream
+        else if( !Tmp2Strm() )
+            return false;
+    }
+    return true;
+}
+
+// Save all dirty streams
+
+bool StgDirEntry::StoreStreams( StgIo& rIo )
+{
+    if( !StoreStream( rIo ) )
+        return false;
+    if( m_pLeft )
+        if( !static_cast<StgDirEntry*>(m_pLeft)->StoreStreams( rIo ) )
+            return false;
+    if( m_pRight )
+        if( !static_cast<StgDirEntry*>(m_pRight)->StoreStreams( rIo ) )
+            return false;
+    if( m_pDown )
+        if( !m_pDown->StoreStreams( rIo ) )
+            return false;
+    return true;
+}
+
+// Revert all directory entries after failure to write the TOC stream
+
+void StgDirEntry::RevertAll()
+{
+    m_aEntry = m_aSave;
+    if( m_pLeft )
+        static_cast<StgDirEntry*>(m_pLeft)->RevertAll();
+    if( m_pRight )
+        static_cast<StgDirEntry*>(m_pRight)->RevertAll();
+    if( m_pDown )
+        m_pDown->RevertAll();
+}
+
+// Look if any element of the tree is dirty
+
+bool StgDirEntry::IsDirty()
+{
+    if( m_bDirty || m_bInvalid )
+        return true;
+    if( m_pLeft && static_cast<StgDirEntry*>(m_pLeft)->IsDirty() )
+        return true;
+    if( m_pRight && static_cast<StgDirEntry*>(m_pRight)->IsDirty() )
+        return true;
+    if( m_pDown && m_pDown->IsDirty() )
+        return true;
+    return false;
+}
+
+// Set up a stream.
+
+void StgDirEntry::OpenStream( StgIo& rIo )
+{
+    sal_Int32 nThreshold = static_cast<sal_uInt16>(rIo.m_aHdr.GetThreshold());
+    delete m_pStgStrm;
+    if( m_aEntry.GetSize() < nThreshold )
+        m_pStgStrm = new StgSmallStrm( rIo, *this );
+    else
+        m_pStgStrm = new StgDataStrm( rIo, *this );
+    if( m_bInvalid && m_aEntry.GetSize() )
+    {
+        // This entry has invalid data, so delete that data
+        SetSize( 0 );
+//      bRemoved = bInvalid = false;
+    }
+    m_nPos = 0;
+}
+
+// Close the open stream without committing. If the entry is marked as
+// temporary, delete it.
+// Do not delete pCurStrm here!
+// (TLX:??? At least pStgStrm must be deleted.)
+
+void StgDirEntry::Close()
+{
+    delete m_pTmpStrm;
+    m_pTmpStrm = nullptr;
+//  nRefCnt  = 0;
+    m_bInvalid = m_bTemp;
+}
+
+// Get the current stream size
+
+sal_Int32 StgDirEntry::GetSize() const
+{
+    sal_Int32 n;
+    if( m_pTmpStrm )
+        n = m_pTmpStrm->GetSize();
+    else if( m_pCurStrm )
+        n = m_pCurStrm->GetSize();
+    else n = m_aEntry.GetSize();
+    return n;
+}
+
+// Set the stream size. This means also creating a temp stream.
+
+bool StgDirEntry::SetSize( sal_Int32 nNewSize )
+{
+    if (
+         !( m_nMode & StreamMode::WRITE ) ||
+         (!m_bDirect && !m_pTmpStrm && !Strm2Tmp())
+       )
+    {
+        return false;
+    }
+
+    if( nNewSize < m_nPos )
+        m_nPos = nNewSize;
+    if( m_pTmpStrm )
+    {
+        m_pTmpStrm->SetSize( nNewSize );
+        m_pStgStrm->GetIo().SetError( m_pTmpStrm->GetError() );
+        return m_pTmpStrm->GetError() == ERRCODE_NONE;
+    }
+    else
+    {
+        OSL_ENSURE( m_pStgStrm, "The pointer may not be NULL!" );
+        if ( !m_pStgStrm )
+            return false;
+
+        bool bRes = false;
+        StgIo& rIo = m_pStgStrm->GetIo();
+        sal_Int32 nThreshold = rIo.m_aHdr.GetThreshold();
+        // ensure the correct storage stream!
+        StgStrm* pOld = nullptr;
+        sal_uInt16 nOldSize = 0;
+        if( nNewSize >= nThreshold && m_pStgStrm->IsSmallStrm() )
+        {
+            pOld = m_pStgStrm;
+            nOldSize = static_cast<sal_uInt16>(pOld->GetSize());
+            m_pStgStrm = new StgDataStrm( rIo, STG_EOF, 0 );
+        }
+        else if( nNewSize < nThreshold && !m_pStgStrm->IsSmallStrm() )
+        {
+            pOld = m_pStgStrm;
+            nOldSize = static_cast<sal_uInt16>(nNewSize);
+            m_pStgStrm = new StgSmallStrm( rIo, STG_EOF );
+        }
+        // now set the new size
+        if( m_pStgStrm->SetSize( nNewSize ) )
+        {
+            // did we create a new stream?
+            if( pOld )
+            {
+                // if so, we probably need to copy the old data
+                if( nOldSize )
+                {
+                    std::unique_ptr<sal_uInt8[]> pBuf(new sal_uInt8[ nOldSize ]);
+                    pOld->Pos2Page( 0 );
+                    m_pStgStrm->Pos2Page( 0 );
+                    if( pOld->Read( pBuf.get(), nOldSize )
+                        && m_pStgStrm->Write( pBuf.get(), nOldSize ) )
+                        bRes = true;
+                }
+                else
+                    bRes = true;
+                if( bRes )
+                {
+                    pOld->SetSize( 0 );
+                    delete pOld;
+                    m_pStgStrm->Pos2Page( m_nPos );
+                    m_pStgStrm->SetEntry( *this );
+                }
+                else
+                {
+                    m_pStgStrm->SetSize( 0 );
+                    delete m_pStgStrm;
+                    m_pStgStrm = pOld;
+                }
+            }
+            else
+            {
+                m_pStgStrm->Pos2Page( m_nPos );
+                bRes = true;
+            }
+        }
+        return bRes;
+    }
+}
+
+// Seek. On negative values, seek to EOF.
+
+sal_Int32 StgDirEntry::Seek( sal_Int32 nNew )
+{
+    if( m_pTmpStrm )
+    {
+        if( nNew < 0 )
+            nNew = m_pTmpStrm->GetSize();
+        nNew = m_pTmpStrm->Seek( nNew );
+    }
+    else if( m_pCurStrm )
+    {
+        if( nNew < 0 )
+            nNew = m_pCurStrm->GetSize();
+        nNew = m_pCurStrm->Seek( nNew );
+    }
+    else
+    {
+        OSL_ENSURE( m_pStgStrm, "The pointer may not be NULL!" );
+        if ( !m_pStgStrm )
+            return m_nPos;
+
+        sal_Int32 nSize = m_aEntry.GetSize();
+
+        if( nNew < 0 )
+            nNew = nSize;
+
+        // try to enlarge, readonly streams do not allow this
+        if( nNew > nSize )
+        {
+            if ( !( m_nMode & StreamMode::WRITE ) || !SetSize( nNew ) )
+            {
+                return m_nPos;
+            }
+            else
+                return Seek( nNew );
+        }
+        m_pStgStrm->Pos2Page( nNew );
+        nNew = m_pStgStrm->GetPos();
+    }
+
+    m_nPos = nNew;
+    return m_nPos;
+}
+
+// Read
+
+sal_Int32 StgDirEntry::Read( void* p, sal_Int32 nLen )
+{
+    if( nLen <= 0 )
+        return 0;
+    if( m_pTmpStrm )
+        nLen = m_pTmpStrm->ReadBytes( p, nLen );
+    else if( m_pCurStrm )
+        nLen = m_pCurStrm->ReadBytes( p, nLen );
+    else
+    {
+        OSL_ENSURE( m_pStgStrm, "The pointer may not be NULL!" );
+        if ( !m_pStgStrm )
+            return 0;
+
+        nLen = m_pStgStrm->Read( p, nLen );
+    }
+
+    m_nPos += nLen;
+    return nLen;
+}
+
+// Write
+
+sal_Int32 StgDirEntry::Write( const void* p, sal_Int32 nLen )
+{
+    if( nLen <= 0 || !( m_nMode & StreamMode::WRITE ) )
+        return 0;
+
+    // Was this stream committed internally and reopened in direct mode?
+    if( m_bDirect && ( m_pCurStrm || m_pTmpStrm ) && !Tmp2Strm() )
+        return 0;
+    // Is this stream opened in transacted mode? Do we have to make a copy?
+    if( !m_bDirect && !m_pTmpStrm && !Strm2Tmp() )
+        return 0;
+
+    OSL_ENSURE( m_pStgStrm, "The pointer may not be NULL!" );
+    if ( !m_pStgStrm )
+        return 0;
+
+    if( m_pTmpStrm )
+    {
+        nLen = m_pTmpStrm->WriteBytes( p, nLen );
+        m_pStgStrm->GetIo().SetError( m_pTmpStrm->GetError() );
+    }
+    else
+    {
+        sal_Int32 nNew = m_nPos + nLen;
+        if( nNew > m_pStgStrm->GetSize() )
+        {
+            if( !SetSize( nNew ) )
+                return 0;
+            m_pStgStrm->Pos2Page( m_nPos );
+        }
+        nLen = m_pStgStrm->Write( p, nLen );
+    }
+    m_nPos += nLen;
+    return nLen;
+}
+
+void StgDirEntry::Copy( BaseStorageStream& rDest )
+{
+    sal_Int32 n = GetSize();
+    if( !(rDest.SetSize( n ) && n) )
+        return;
+
+    sal_uInt64 Pos = rDest.Tell();
+    sal_uInt8 aTempBytes[ 4096 ];
+    void* p = static_cast<void*>( aTempBytes );
+    Seek( 0 );
+    rDest.Seek( 0 );
+    while( n )
+    {
+        sal_Int32 nn = n;
+        if( nn > 4096 )
+            nn = 4096;
+        if( Read( p, nn ) != nn )
+            break;
+        if( sal::static_int_cast<sal_Int32>(rDest.Write( p, nn )) != nn )
+            break;
+        n -= nn;
+    }
+    rDest.Seek( Pos );             // ?! Seems to be undocumented !
+}
+
+// Commit this entry
+
+bool StgDirEntry::Commit()
+{
+    // OSL_ENSURE( nMode & StreamMode::WRITE, "Trying to commit readonly stream!" );
+
+    m_aSave = m_aEntry;
+    bool bRes = true;
+    if( m_aEntry.GetType() == STG_STREAM )
+    {
+        if( m_pTmpStrm )
+        {
+            delete m_pCurStrm;
+            m_pCurStrm = m_pTmpStrm;
+            m_pTmpStrm = nullptr;
+        }
+        if( m_bRemoved )
+            // Delete the stream if needed
+            if( m_pStgStrm )
+                m_pStgStrm->SetSize( 0 );
+    }
+    else if( m_aEntry.GetType() == STG_STORAGE && m_bDirect && bRes )
+    {
+        StgIterator aIter( *this );
+        for( StgDirEntry* p = aIter.First(); p && bRes; p = aIter.Next() )
+            bRes = p->Commit();
+    }
+    return bRes;
+}
+
+// Copy the stg stream to the temp stream
+
+bool StgDirEntry::Strm2Tmp()
+{
+    if( !m_pTmpStrm )
+    {
+        sal_uInt64 n = 0;
+        if( m_pCurStrm )
+        {
+            // It was already committed once
+            m_pTmpStrm = new StgTmpStrm;
+            if( m_pTmpStrm->GetError() == ERRCODE_NONE && m_pTmpStrm->Copy( *m_pCurStrm ) )
+                return true;
+            n = 1;  // indicates error
+        }
+        else
+        {
+            n = m_aEntry.GetSize();
+            m_pTmpStrm = new StgTmpStrm( n );
+            if( m_pTmpStrm->GetError() == ERRCODE_NONE )
+            {
+                if( n )
+                {
+                    OSL_ENSURE( m_pStgStrm, "The pointer may not be NULL!" );
+                    if ( !m_pStgStrm )
+                        return false;
+
+                    sal_uInt8 aTempBytes[ 4096 ];
+                    void* p = static_cast<void*>( aTempBytes );
+                    m_pStgStrm->Pos2Page( 0 );
+                    while( n )
+                    {
+                        sal_uInt64 nn = n;
+                        if( nn > 4096 )
+                            nn = 4096;
+                        if( static_cast<sal_uInt64>(m_pStgStrm->Read( p, nn )) != nn )
+                            break;
+                        if (m_pTmpStrm->WriteBytes( p, nn ) != nn)
+                            break;
+                        n -= nn;
+                    }
+                    m_pStgStrm->Pos2Page( m_nPos );
+                    m_pTmpStrm->Seek( m_nPos );
+                }
+            }
+            else
+                n = 1;
+        }
+
+        if( n )
+        {
+            OSL_ENSURE( m_pStgStrm, "The pointer may not be NULL!" );
+            if ( m_pStgStrm )
+                m_pStgStrm->GetIo().SetError( m_pTmpStrm->GetError() );
+
+            delete m_pTmpStrm;
+            m_pTmpStrm = nullptr;
+            return false;
+        }
+    }
+    return true;
+}
+
+// Copy the temp stream to the stg stream during the final commit
+
+bool StgDirEntry::Tmp2Strm()
+{
+    // We did commit once, but have not written since then
+    if( !m_pTmpStrm )
+    {
+        m_pTmpStrm = m_pCurStrm;
+        m_pCurStrm = nullptr;
+    }
+    if( m_pTmpStrm )
+    {
+        OSL_ENSURE( m_pStgStrm, "The pointer may not be NULL!" );
+        if ( !m_pStgStrm )
+            return false;
+        sal_uInt64 n = m_pTmpStrm->GetSize();
+        std::unique_ptr<StgStrm> pNewStrm;
+        StgIo& rIo = m_pStgStrm->GetIo();
+        sal_uInt64 nThreshold = rIo.m_aHdr.GetThreshold();
+        if( n < nThreshold )
+            pNewStrm.reset(new StgSmallStrm( rIo, STG_EOF ));
+        else
+            pNewStrm.reset(new StgDataStrm( rIo, STG_EOF ));
+        if( pNewStrm->SetSize( n ) )
+        {
+            sal_uInt8 p[ 4096 ];
+            m_pTmpStrm->Seek( 0 );
+            while( n )
+            {
+                sal_uInt64 nn = n;
+                if( nn > 4096 )
+                    nn = 4096;
+                if (m_pTmpStrm->ReadBytes( p, nn ) != nn)
+                    break;
+                if( static_cast<sal_uInt64>(pNewStrm->Write( p, nn )) != nn )
+                    break;
+                n -= nn;
+            }
+            if( n )
+            {
+                m_pTmpStrm->Seek( m_nPos );
+                m_pStgStrm->GetIo().SetError( m_pTmpStrm->GetError() );
+                return false;
+            }
+            else
+            {
+                m_pStgStrm->SetSize( 0 );
+                delete m_pStgStrm;
+                m_pStgStrm = pNewStrm.release();
+                m_pStgStrm->SetEntry(*this);
+                m_pStgStrm->Pos2Page(m_nPos);
+                delete m_pTmpStrm;
+                delete m_pCurStrm;
+                m_pTmpStrm = m_pCurStrm = nullptr;
+                m_aSave = m_aEntry;
+            }
+        }
+    }
+    return true;
+}
+
+// Invalidate all open entries by setting the RefCount to 0. If the bDel
+// flag is set, also set the invalid flag to indicate deletion during the
+// next dir stream flush.
+
+void StgDirEntry::Invalidate( bool bDel )
+{
+//  nRefCnt = 0;
+    if( bDel )
+        m_bRemoved = m_bInvalid = true;
+    switch( m_aEntry.GetType() )
+    {
+        case STG_STORAGE:
+        case STG_ROOT:
+        {
+            StgIterator aIter( *this );
+            for( StgDirEntry* p = aIter.First(); p; p = aIter.Next() )
+                p->Invalidate( bDel );
+            break;
+        }
+        default:
+            break;
+    }
+}
+
+///////////////////////////// class StgDirStrm
+
+// This specialized stream is the maintenance stream for the directory tree.
+
+StgDirStrm::StgDirStrm( StgIo& r )
+          : StgDataStrm( r, r.m_aHdr.GetTOCStart(), -1 )
+          , m_pRoot( nullptr )
+{
+    if( r.GetError() )
+        return;
+    if( m_nStart == STG_EOF )
+    {
+        StgEntry aRoot;
+        aRoot.Init();
+        static constexpr OUStringLiteral sRootEntry = u"Root Entry";
+        aRoot.SetName( sRootEntry );
+        aRoot.SetType( STG_ROOT );
+        m_pRoot = new StgDirEntry( std::move(aRoot) );
+        m_pRoot->SetDirty();
+    }
+    else
+    {
+        // temporarily use this instance as owner, so
+        // the TOC pages can be removed.
+        m_pEntry = reinterpret_cast<StgDirEntry*>(this); // just for a bit pattern
+        SetupEntry( 0, m_pRoot );
+        m_pEntry = nullptr;
+    }
+}
+
+StgDirStrm::~StgDirStrm()
+{
+    delete m_pRoot;
+}
+
+// Recursively parse the directory tree during reading the TOC stream
+
+void StgDirStrm::SetupEntry( sal_Int32 n, StgDirEntry* pUpper )
+{
+    void* p = ( n == STG_FREE ) ? nullptr : GetEntry( n, false );
+    if( !p )
+        return;
+
+    SvStream *pUnderlyingStream = m_rIo.GetStrm();
+    sal_uInt64 nUnderlyingStreamSize = pUnderlyingStream->TellEnd();
+
+    bool bOk(false);
+    std::unique_ptr<StgDirEntry> pCur(new StgDirEntry( p, STGENTRY_SIZE, nUnderlyingStreamSize, &bOk ));
+
+    if( !bOk )
+    {
+        m_rIo.SetError( SVSTREAM_GENERALERROR );
+        // an error occurred
+        return;
+    }
+
+    // better it is
+    if( !pUpper )
+        pCur->m_aEntry.SetType( STG_ROOT );
+
+    sal_Int32 nLeft = pCur->m_aEntry.GetLeaf( STG_LEFT );
+    sal_Int32 nRight = pCur->m_aEntry.GetLeaf( STG_RIGHT );
+    // substorage?
+    sal_Int32 nLeaf = STG_FREE;
+    if( pCur->m_aEntry.GetType() == STG_STORAGE || pCur->m_aEntry.GetType() == STG_ROOT )
+    {
+        nLeaf = pCur->m_aEntry.GetLeaf( STG_CHILD );
+        if (nLeaf != STG_FREE && nLeaf == n)
+        {
+            m_rIo.SetError( SVSTREAM_GENERALERROR );
+            return;
+        }
+    }
+
+    if( !(nLeaf != 0 && nLeft != 0 && nRight != 0) )
+        return;
+
+    //fdo#41642
+    StgDirEntry *pUp = pUpper;
+    while (pUp)
+    {
+        if (pUp->m_aEntry.GetLeaf(STG_CHILD) == nLeaf)
+        {
+            SAL_WARN("sot", "Leaf node of upper StgDirEntry is same as current StgDirEntry's leaf node. Circular entry chain, discarding link");
+            return;
+        }
+        pUp = pUp->m_pUp;
+    }
+
+    if( StgAvlNode::Insert
+        ( reinterpret_cast<StgAvlNode**>( pUpper ? &pUpper->m_pDown : &m_pRoot ), pCur.get() ) )
+    {
+        pCur->m_pUp    = pUpper;
+    }
+    else
+    {
+        // bnc#682484: There are some really broken docs out there
+        // that contain duplicate entries in 'Directory' section
+        // so don't set the error flag here and just skip those
+        // (was: rIo.SetError( SVSTREAM_CANNOT_MAKE );)
+        return;
+    }
+    SetupEntry( nLeft, pUpper );
+    SetupEntry( nRight, pUpper );
+    SetupEntry( nLeaf, pCur.release() );
+}
+
+// Extend or shrink the directory stream.
+
+bool StgDirStrm::SetSize( sal_Int32 nBytes )
+{
+    // Always allocate full pages
+    if ( nBytes < 0 )
+        nBytes = 0;
+
+    nBytes = ( ( nBytes + m_nPageSize - 1 ) / m_nPageSize ) * m_nPageSize;
+    return StgStrm::SetSize( nBytes );
+}
+
+// Save the TOC stream into a new substream after saving all data streams
+
+bool StgDirStrm::Store()
+{
+    if( !m_pRoot || !m_pRoot->IsDirty() )
+        return true;
+    if( !m_pRoot->StoreStreams( m_rIo ) )
+        return false;
+    // After writing all streams, the data FAT stream has changed,
+    // so we have to commit the root again
+    m_pRoot->Commit();
+    // We want a completely new stream, so fake an empty stream
+    sal_Int32 nOldStart = m_nStart;       // save for later deletion
+    sal_Int32 nOldSize  = m_nSize;
+    m_nStart = m_nPage = STG_EOF;
+    m_nSize = 0;
+    SetPos(0, true);
+    m_nOffset = 0;
+    // Delete all temporary entries
+    m_pRoot->DelTemp( false );
+    // set the entry numbers
+    sal_Int32 n = 0;
+    m_pRoot->Enum( n );
+    if( !SetSize( n * STGENTRY_SIZE ) )
+    {
+        m_nStart = nOldStart; m_nSize = nOldSize;
+        m_pRoot->RevertAll();
+        return false;
+    }
+    // set up the cache elements for the new stream
+    if( !Copy( STG_FREE, m_nSize ) )
+    {
+        m_pRoot->RevertAll();
+        return false;
+    }
+    // Write the data to the new stream
+    if( !m_pRoot->Store( *this ) )
+    {
+        m_pRoot->RevertAll();
+        return false;
+    }
+    // fill any remaining entries with empty data
+    sal_Int32 ne = m_nSize / STGENTRY_SIZE;
+    StgEntry aEmpty;
+    aEmpty.Init();
+    while( n < ne )
+    {
+        void* p = GetEntry( n++, true );
+        if( !p )
+        {
+            m_pRoot->RevertAll();
+            return false;
+        }
+        aEmpty.Store( p );
+    }
+    // Now we can release the old stream
+    m_pFat->FreePages( nOldStart, true );
+    m_rIo.m_aHdr.SetTOCStart( m_nStart );
+    return true;
+}
+
+// Get a dir entry.
+
+void* StgDirStrm::GetEntry( sal_Int32 n, bool bDirty )
+{
+    return n < 0 || n >= m_nSize / STGENTRY_SIZE
+        ? nullptr : GetPtr( n * STGENTRY_SIZE, bDirty );
+}
+
+// Find a dir entry.
+
+StgDirEntry* StgDirStrm::Find( StgDirEntry& rStg, const OUString& rName )
+{
+    if( rStg.m_pDown )
+    {
+        StgEntry aEntry;
+        aEntry.Init();
+        aEntry.SetName( rName );
+        // Look in the directory attached to the entry
+        StgDirEntry aTest( std::move(aEntry) );
+        return static_cast<StgDirEntry*>( rStg.m_pDown->Find( &aTest ) );
+    }
+    else
+        return nullptr;
+}
+
+// Create a new entry.
+
+StgDirEntry* StgDirStrm::Create( StgDirEntry& rStg, const OUString& rName, StgEntryType eType )
+{
+    StgEntry aEntry;
+    aEntry.Init();
+    aEntry.SetType( eType );
+    aEntry.SetName( rName );
+    StgDirEntry* pRes = Find( rStg, rName );
+    if( pRes )
+    {
+        if( !pRes->m_bInvalid )
+        {
+            m_rIo.SetError( SVSTREAM_CANNOT_MAKE );
+            return nullptr;
+        }
+        pRes->m_bInvalid =
+        pRes->m_bRemoved =
+        pRes->m_bTemp    = false;
+        pRes->m_bDirty   = true;
+        return pRes;
+    }
+    else
+    {
+        std::unique_ptr<StgDirEntry> pNewRes(new StgDirEntry( std::move(aEntry) ));
+        if( StgAvlNode::Insert( reinterpret_cast<StgAvlNode**>(&rStg.m_pDown), pNewRes.get() ) )
+        {
+            pNewRes->m_pUp    = &rStg;
+            pNewRes->m_bDirty = true;
+        }
+        else
+        {
+            m_rIo.SetError( SVSTREAM_CANNOT_MAKE );
+            pNewRes.reset();
+        }
+        return pNewRes.release();
+    }
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/sot/source/sdstor/stgdir.hxx b/sot/source/sdstor/stgdir.hxx
new file mode 100644
index 000000000..3605c27ac
--- /dev/null
+++ b/sot/source/sdstor/stgdir.hxx
@@ -0,0 +1,111 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+#ifndef INCLUDED_SOT_SOURCE_SDSTOR_STGDIR_HXX
+#define INCLUDED_SOT_SOURCE_SDSTOR_STGDIR_HXX
+
+#include "stgavl.hxx"
+#include "stgelem.hxx"
+#include "stgstrms.hxx"
+
+class StgIo;
+class StgDirStrm;
+
+class BaseStorageStream;
+class StgDirEntry : public StgAvlNode
+{
+    friend class StgIterator;
+    friend class StgDirStrm;
+    StgEntry     m_aSave;                     // original dir entry
+    StgDirEntry* m_pUp;                      // parent directory
+    StgDirEntry* m_pDown;                    // child directory for storages
+    StgStrm*     m_pStgStrm;                  // storage stream
+    StgTmpStrm*  m_pTmpStrm;                  // temporary stream
+    StgTmpStrm*  m_pCurStrm;                  // temp stream after commit
+    sal_Int32    m_nEntry;                    // entry # in TOC stream (temp)
+    sal_Int32    m_nPos;                      // current position
+    bool         m_bDirty;                    // dirty directory entry
+    bool         m_bRemoved;                  // removed per Invalidate()
+    void         InitMembers();             // ctor helper
+    virtual sal_Int32 Compare( const StgAvlNode* ) const override;
+    bool         StoreStream( StgIo& );     // store the stream
+    bool         StoreStreams( StgIo& );    // store all streams
+    void         RevertAll();               // revert the whole tree
+    bool         Strm2Tmp();                // copy stgstream to temp file
+    bool         Tmp2Strm();                // copy temp file to stgstream
+public:
+    StgEntry     m_aEntry;                    // entry data
+    sal_Int32        m_nRefCnt;                   // reference count
+    StreamMode   m_nMode;                     // open mode
+    bool         m_bTemp;                     // true: delete on dir flush
+    bool         m_bDirect;                   // true: direct mode
+    bool         m_bZombie;                   // true: Removed From StgIo
+    bool         m_bInvalid;                  // true: invalid entry
+    StgDirEntry(const void* pBuffer, sal_uInt32 nBufferLen,
+                sal_uInt64 nUnderlyingStreamSize, bool * pbOk);
+    explicit StgDirEntry( const StgEntry& );
+    virtual ~StgDirEntry() override;
+
+    void Invalidate( bool );                // invalidate all open entries
+    void Enum( sal_Int32& );                // enumerate entries for iteration
+    void DelTemp( bool );                   // delete temporary entries
+    bool Store( StgDirStrm& );              // save entry into dir strm
+
+    void SetDirty()  { m_bDirty = true; }
+    bool IsDirty();
+
+    bool Commit();
+
+    void  OpenStream( StgIo& );     // set up an appropriate stream
+    void  Close();
+    sal_Int32 GetSize() const;
+    bool  SetSize( sal_Int32 );
+    sal_Int32 Seek( sal_Int32 );
+    sal_Int32 Read( void*, sal_Int32 );
+    sal_Int32 Write( const void*, sal_Int32 );
+    void  Copy( BaseStorageStream& );
+};
+
+class StgDirStrm : public StgDataStrm
+{
+    friend class StgIterator;
+    StgDirEntry* m_pRoot;                         // root of dir tree
+    void         SetupEntry( sal_Int32, StgDirEntry* );
+public:
+    explicit StgDirStrm( StgIo& );
+    virtual ~StgDirStrm() override;
+    virtual bool SetSize( sal_Int32 ) override;              // change the size
+    bool         Store();
+    void*        GetEntry( sal_Int32 n, bool );// get an entry
+    StgDirEntry* GetRoot() { return m_pRoot; }
+    static StgDirEntry* Find( StgDirEntry&, const OUString& );
+    StgDirEntry* Create( StgDirEntry&, const OUString&, StgEntryType );
+};
+
+class StgIterator : public StgAvlIterator
+{
+public:
+    explicit StgIterator( StgDirEntry& rStg ) : StgAvlIterator( rStg.m_pDown ) {}
+    StgDirEntry* First() { return static_cast<StgDirEntry*>( StgAvlIterator::First() ); }
+    StgDirEntry* Next()  { return static_cast<StgDirEntry*>( StgAvlIterator::Next() );  }
+};
+
+#endif
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/sot/source/sdstor/stgelem.cxx b/sot/source/sdstor/stgelem.cxx
new file mode 100644
index 000000000..ff41d8d70
--- /dev/null
+++ b/sot/source/sdstor/stgelem.cxx
@@ -0,0 +1,484 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+
+#include <string.h>
+
+#include <o3tl/safeint.hxx>
+#include <rtl/ustring.hxx>
+#include <com/sun/star/lang/Locale.hpp>
+#include <unotools/charclass.hxx>
+#include <sot/stg.hxx>
+#include "stgelem.hxx"
+#include "stgio.hxx"
+
+const sal_uInt16 nMaxLegalStr = 31;
+
+const sal_uInt8 cStgSignature[ 8 ] = { 0xD0,0xCF,0x11,0xE0,0xA1,0xB1,0x1A,0xE1 };
+
+////////////////////////////// struct ClsId
+
+SvStream& ReadClsId( SvStream& r, ClsId& rId )
+{
+    r.ReadUInt32( rId.Data1 )
+     .ReadUInt16( rId.Data2 )
+     .ReadUInt16( rId.Data3 )
+     .ReadUChar( rId.Data4[0] )
+     .ReadUChar( rId.Data4[1] )
+     .ReadUChar( rId.Data4[2] )
+     .ReadUChar( rId.Data4[3] )
+     .ReadUChar( rId.Data4[4] )
+     .ReadUChar( rId.Data4[5] )
+     .ReadUChar( rId.Data4[6] )
+     .ReadUChar( rId.Data4[7] );
+    return r;
+}
+
+SvStream& WriteClsId( SvStream& r, const ClsId& rId )
+{
+    return
+       r .WriteUInt32( rId.Data1 )
+         .WriteUInt16( rId.Data2 )
+         .WriteUInt16( rId.Data3 )
+         .WriteUChar( rId.Data4[0] )
+         .WriteUChar( rId.Data4[1] )
+         .WriteUChar( rId.Data4[2] )
+         .WriteUChar( rId.Data4[3] )
+         .WriteUChar( rId.Data4[4] )
+         .WriteUChar( rId.Data4[5] )
+         .WriteUChar( rId.Data4[6] )
+         .WriteUChar( rId.Data4[7] );
+}
+
+///////////////////////////// class StgHeader
+
+StgHeader::StgHeader()
+: m_nVersion( 0 )
+, m_nByteOrder( 0 )
+, m_nPageSize( 0 )
+, m_nDataPageSize( 0 )
+, m_bDirty( sal_uInt8(false) )
+, m_nFATSize( 0 )
+, m_nTOCstrm( 0 )
+, m_nReserved( 0 )
+, m_nThreshold( 0 )
+, m_nDataFAT( 0 )
+, m_nDataFATSize( 0 )
+, m_nMasterChain( 0 )
+, m_nMaster( 0 )
+{
+}
+
+void StgHeader::Init()
+{
+    memcpy( m_cSignature, cStgSignature, 8 );
+    memset( &m_aClsId, 0, sizeof( ClsId ) );
+    m_nVersion      = 0x0003003B;
+    m_nByteOrder    = 0xFFFE;
+    m_nPageSize     = 9;          // 512 bytes
+    m_nDataPageSize = 6;          // 64 bytes
+    m_bDirty = sal_uInt8(false);
+    memset( m_cReserved, 0, sizeof( m_cReserved ) );
+    m_nFATSize = 0;
+    m_nTOCstrm = 0;
+    m_nReserved = 0;
+    m_nThreshold    = 4096;
+    m_nDataFAT = 0;
+    m_nDataFATSize  = 0;
+    m_nMasterChain  = STG_EOF;
+
+    SetTOCStart( STG_EOF );
+    SetDataFATStart( STG_EOF );
+    for( short i = 0; i < cFATPagesInHeader; i++ )
+        SetFATPage( i, STG_FREE );
+}
+
+bool StgHeader::Load( StgIo& rIo )
+{
+    bool bResult = false;
+    if ( rIo.GetStrm() )
+    {
+        SvStream& r = *rIo.GetStrm();
+        bResult = Load( r );
+        bResult = ( bResult && rIo.Good() );
+    }
+
+    return bResult;
+}
+
+bool StgHeader::Load( SvStream& r )
+{
+    r.Seek( 0 );
+    r.ReadBytes( m_cSignature, 8 );
+    ReadClsId( r, m_aClsId );         // 08 Class ID
+    r.ReadInt32( m_nVersion )                   // 1A version number
+     .ReadUInt16( m_nByteOrder )                 // 1C Unicode byte order indicator
+     .ReadInt16( m_nPageSize )                  // 1E 1 << nPageSize = block size
+     .ReadInt16( m_nDataPageSize );             // 20 1 << this size == data block size
+    if (!r.good())
+        return false;
+    if (!checkSeek(r, r.Tell() + 10))
+        return false;
+    r.ReadInt32( m_nFATSize )                   // 2C total number of FAT pages
+     .ReadInt32( m_nTOCstrm )                   // 30 starting page for the TOC stream
+     .ReadInt32( m_nReserved )                  // 34
+     .ReadInt32( m_nThreshold )                 // 38 minimum file size for big data
+     .ReadInt32( m_nDataFAT )                   // 3C page # of 1st data FAT block
+     .ReadInt32( m_nDataFATSize )               // 40 # of data FATpages
+     .ReadInt32( m_nMasterChain )               // 44 chain to the next master block
+     .ReadInt32( m_nMaster );                   // 48 # of additional master blocks
+    for(sal_Int32 & i : m_nMasterFAT)
+        r.ReadInt32( i );
+
+    return r.good() && Check();
+}
+
+bool StgHeader::Store( StgIo& rIo )
+{
+    if( !m_bDirty )
+        return true;
+
+    SvStream& r = *rIo.GetStrm();
+    r.Seek( 0 );
+    r.WriteBytes( m_cSignature, 8 );
+    WriteClsId( r, m_aClsId );                   // 08 Class ID
+    r.WriteInt32( m_nVersion )                   // 1A version number
+     .WriteUInt16( m_nByteOrder )                 // 1C Unicode byte order indicator
+     .WriteInt16( m_nPageSize )                  // 1E 1 << nPageSize = block size
+     .WriteInt16( m_nDataPageSize )              // 20 1 << this size == data block size
+     .WriteInt32( 0 ).WriteInt32( 0 ).WriteInt16( 0 )
+     .WriteInt32( m_nFATSize )                   // 2C total number of FAT pages
+     .WriteInt32( m_nTOCstrm )                   // 30 starting page for the TOC stream
+     .WriteInt32( m_nReserved )                  // 34
+     .WriteInt32( m_nThreshold )                 // 38 minimum file size for big data
+     .WriteInt32( m_nDataFAT )                   // 3C page # of 1st data FAT block
+     .WriteInt32( m_nDataFATSize )               // 40 # of data FAT pages
+     .WriteInt32( m_nMasterChain )               // 44 chain to the next master block
+     .WriteInt32( m_nMaster );                   // 48 # of additional master blocks
+    for(sal_Int32 i : m_nMasterFAT)
+        r.WriteInt32( i );
+    m_bDirty = sal_uInt8(!rIo.Good());
+    return !m_bDirty;
+}
+
+static bool lcl_wontoverflow(short shift)
+{
+    return shift >= 0 && shift < short(sizeof(short)) * 8 - 1;
+}
+
+static bool isKnownSpecial(sal_Int32 nLocation)
+{
+    return (nLocation == STG_FREE ||
+            nLocation == STG_EOF ||
+            nLocation == STG_FAT ||
+            nLocation == STG_MASTER);
+}
+
+// Perform thorough checks also on unknown variables
+bool StgHeader::Check()
+{
+    return  memcmp( m_cSignature, cStgSignature, 8 ) == 0
+            && static_cast<short>( m_nVersion >> 16 ) == 3
+            && m_nPageSize == 9
+            && lcl_wontoverflow(m_nPageSize)
+            && lcl_wontoverflow(m_nDataPageSize)
+            && m_nFATSize > 0
+            && m_nTOCstrm >= 0
+            && m_nThreshold > 0
+            && ( isKnownSpecial(m_nDataFAT) || ( m_nDataFAT >= 0 && m_nDataFATSize > 0 ) )
+            && ( isKnownSpecial(m_nMasterChain) || m_nMasterChain >=0 )
+            && m_nMaster >= 0;
+}
+
+sal_Int32 StgHeader::GetFATPage( short n ) const
+{
+    if( n >= 0 && n < cFATPagesInHeader )
+        return m_nMasterFAT[ n ];
+    else
+        return STG_EOF;
+}
+
+void StgHeader::SetFATPage( short n, sal_Int32 nb )
+{
+    if( n >= 0 && n < cFATPagesInHeader )
+    {
+        if( m_nMasterFAT[ n ] != nb )
+        {
+            m_bDirty = sal_uInt8(true);
+            m_nMasterFAT[ n ] = nb;
+        }
+    }
+}
+
+void StgHeader::SetTOCStart( sal_Int32 n )
+{
+    if( n != m_nTOCstrm )
+    {
+        m_bDirty = sal_uInt8(true);
+        m_nTOCstrm = n;
+    }
+}
+
+void StgHeader::SetDataFATStart( sal_Int32 n )
+{
+    if( n != m_nDataFAT )
+    {
+        m_bDirty = sal_uInt8(true);
+        m_nDataFAT = n;
+    }
+}
+
+void StgHeader::SetDataFATSize( sal_Int32 n )
+{
+    if( n != m_nDataFATSize )
+    {
+        m_bDirty = sal_uInt8(true);
+        m_nDataFATSize = n;
+    }
+}
+
+void StgHeader::SetFATSize( sal_Int32 n )
+{
+    if( n != m_nFATSize )
+    {
+        m_bDirty = sal_uInt8(true);
+        m_nFATSize = n;
+    }
+}
+
+void StgHeader::SetFATChain( sal_Int32 n )
+{
+    if( n != m_nMasterChain )
+    {
+        m_bDirty = sal_uInt8(true);
+        m_nMasterChain = n;
+    }
+}
+
+void StgHeader::SetMasters( sal_Int32 n )
+{
+    if( n != m_nMaster )
+    {
+        m_bDirty = sal_uInt8(true);
+        m_nMaster = n;
+    }
+}
+
+///////////////////////////// class StgEntry
+
+void StgEntry::Init()
+{
+    memset( m_nName, 0, sizeof( m_nName ) );
+    m_nNameLen = 0;
+    m_cType = 0;
+    m_cFlags = 0;
+    m_nLeft = 0;
+    m_nRight = 0;
+    m_nChild = 0;
+    memset( &m_aClsId, 0, sizeof( m_aClsId ) );
+    m_nFlags = 0;
+    m_nMtime[0] = 0; m_nMtime[1] = 0;
+    m_nAtime[0] = 0; m_nAtime[1] = 0;
+    m_nPage1 = 0;
+    m_nSize = 0;
+    m_nUnknown = 0;
+
+    SetLeaf( STG_LEFT,  STG_FREE );
+    SetLeaf( STG_RIGHT, STG_FREE );
+    SetLeaf( STG_CHILD, STG_FREE );
+    SetLeaf( STG_DATA,  STG_EOF );
+}
+
+static OUString ToUpperUnicode( const OUString & rStr )
+{
+    // I don't know the locale, so en_US is hopefully fine
+    static CharClass aCC( LanguageTag( css::lang::Locale( "en", "US", "" )) );
+    return aCC.uppercase( rStr );
+}
+
+void StgEntry::SetName( const OUString& rName )
+{
+    // I don't know the locale, so en_US is hopefully fine
+    m_aName = ToUpperUnicode( rName );
+    if(m_aName.getLength() > nMaxLegalStr)
+    {
+        m_aName = m_aName.copy(0, nMaxLegalStr);
+    }
+
+    sal_Int32 i;
+    for( i = 0; i < rName.getLength() && i <= nMaxLegalStr; i++ )
+    {
+        m_nName[ i ] = rName[ i ];
+    }
+    while (i <= nMaxLegalStr)
+    {
+        m_nName[ i++ ] = 0;
+    }
+    m_nNameLen = ( rName.getLength() + 1 ) << 1;
+}
+
+sal_Int32 StgEntry::GetLeaf( StgEntryRef eRef ) const
+{
+    sal_Int32 n = -1;
+    switch( eRef )
+    {
+    case STG_LEFT:  n = m_nLeft;  break;
+    case STG_RIGHT: n = m_nRight; break;
+    case STG_CHILD: n = m_nChild; break;
+    case STG_DATA:  n = m_nPage1; break;
+    }
+    return n;
+}
+
+void StgEntry::SetLeaf( StgEntryRef eRef, sal_Int32 nPage )
+{
+    switch( eRef )
+    {
+    case STG_LEFT:  m_nLeft  = nPage; break;
+    case STG_RIGHT: m_nRight = nPage; break;
+    case STG_CHILD: m_nChild = nPage; break;
+    case STG_DATA:  m_nPage1 = nPage; break;
+    }
+}
+
+void StgEntry::SetClassId( const ClsId& r )
+{
+    memcpy( &m_aClsId, &r, sizeof( ClsId ) );
+}
+
+void StgEntry::GetName( OUString& rName ) const
+{
+    sal_uInt16 n = m_nNameLen;
+    if( n )
+        n = ( n >> 1 ) - 1;
+    rName = OUString(m_nName, n);
+}
+
+// Compare two entries. Do this case-insensitive.
+
+sal_Int32 StgEntry::Compare( const StgEntry& r ) const
+{
+    if (r.m_nNameLen != m_nNameLen)
+        return r.m_nNameLen > m_nNameLen ? 1 : -1;
+    else
+        return r.m_aName.compareTo(m_aName);
+}
+
+// These load/store operations are a bit more complicated,
+// since they have to copy their contents into a packed structure.
+
+bool StgEntry::Load(const void* pFrom, sal_uInt32 nBufSize, sal_uInt64 nUnderlyingStreamSize)
+{
+    if ( nBufSize < 128 )
+        return false;
+
+    SvMemoryStream r( const_cast<void *>(pFrom), nBufSize, StreamMode::READ );
+    for(sal_Unicode & i : m_nName)
+        r.ReadUtf16( i );             // 00 name as WCHAR
+    r.ReadUInt16( m_nNameLen )                   // 40 size of name in bytes including 00H
+     .ReadUChar( m_cType )                      // 42 entry type
+     .ReadUChar( m_cFlags )                     // 43 0 or 1 (tree balance?)
+     .ReadInt32( m_nLeft )                      // 44 left node entry
+     .ReadInt32( m_nRight )                     // 48 right node entry
+     .ReadInt32( m_nChild );                    // 4C 1st child entry if storage
+    ReadClsId( r, m_aClsId );         // 50 class ID (optional)
+    r.ReadInt32( m_nFlags )                     // 60 state flags(?)
+     .ReadInt32( m_nMtime[ 0 ] )                // 64 modification time
+     .ReadInt32( m_nMtime[ 1 ] )                // 64 modification time
+     .ReadInt32( m_nAtime[ 0 ] )                // 6C creation and access time
+     .ReadInt32( m_nAtime[ 1 ] )                // 6C creation and access time
+     .ReadInt32( m_nPage1 )                     // 74 starting block (either direct or translated)
+     .ReadInt32( m_nSize )                      // 78 file size
+     .ReadInt32( m_nUnknown );                  // 7C unknown
+
+    sal_uInt16 n = m_nNameLen;
+    if( n )
+        n = ( n >> 1 ) - 1;
+
+    if (n > nMaxLegalStr)
+        return false;
+
+    if (m_cType != STG_STORAGE)
+    {
+        if (m_nPage1 < 0 && !isKnownSpecial(m_nPage1))
+        {
+            //bad pageid
+            return false;
+        }
+        if (m_cType == STG_EMPTY)
+        {
+            /*
+             tdf#112399 opens fine in MSOffice 2013 despite a massive m_nSize field
+
+             Free (unused) directory entries are marked with Object Type 0x0
+             (unknown or unallocated). The entire directory entry must consist of
+             all zeroes except for the child, right sibling, and left sibling
+             pointers, which must be initialized to NOSTREAM (0xFFFFFFFF).
+            */
+            m_nSize = 0;
+        }
+        if (m_nSize < 0)
+        {
+            // the size makes no sense for the substorage
+            // TODO/LATER: actually the size should be an unsigned value, but
+            // in this case it would mean a stream of more than 2Gb
+            return false;
+        }
+        if (o3tl::make_unsigned(m_nSize) > nUnderlyingStreamSize)
+        {
+            // surely an entry cannot be larger than the underlying file
+            return false;
+        }
+
+    }
+
+    m_aName = OUString(m_nName , n);
+    // I don't know the locale, so en_US is hopefully fine
+    m_aName = ToUpperUnicode( m_aName );
+    if(m_aName.getLength() > nMaxLegalStr)
+    {
+        m_aName = m_aName.copy(0, nMaxLegalStr);
+    }
+
+    return true;
+}
+
+void StgEntry::Store( void* pTo )
+{
+    SvMemoryStream r( pTo, 128, StreamMode::WRITE );
+    for(sal_Unicode i : m_nName)
+        r.WriteUInt16( i );            // 00 name as WCHAR
+    r.WriteUInt16( m_nNameLen )                   // 40 size of name in bytes including 00H
+     .WriteUChar( m_cType )                      // 42 entry type
+     .WriteUChar( m_cFlags )                     // 43 0 or 1 (tree balance?)
+     .WriteInt32( m_nLeft )                      // 44 left node entry
+     .WriteInt32( m_nRight )                     // 48 right node entry
+     .WriteInt32( m_nChild );                    // 4C 1st child entry if storage;
+    WriteClsId( r, m_aClsId );                   // 50 class ID (optional)
+    r.WriteInt32( m_nFlags )                     // 60 state flags(?)
+     .WriteInt32( m_nMtime[ 0 ] )                // 64 modification time
+     .WriteInt32( m_nMtime[ 1 ] )                // 64 modification time
+     .WriteInt32( m_nAtime[ 0 ] )                // 6C creation and access time
+     .WriteInt32( m_nAtime[ 1 ] )                // 6C creation and access time
+     .WriteInt32( m_nPage1 )                     // 74 starting block (either direct or translated)
+     .WriteInt32( m_nSize )                      // 78 file size
+     .WriteInt32( m_nUnknown );                  // 7C unknown
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/sot/source/sdstor/stgelem.hxx b/sot/source/sdstor/stgelem.hxx
new file mode 100644
index 000000000..855b2b879
--- /dev/null
+++ b/sot/source/sdstor/stgelem.hxx
@@ -0,0 +1,146 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+// This file reflects the structure of MS file elements.
+// It is very sensitive to alignment!
+
+#ifndef INCLUDED_SOT_SOURCE_SDSTOR_STGELEM_HXX
+#define INCLUDED_SOT_SOURCE_SDSTOR_STGELEM_HXX
+
+#include <sot/stg.hxx>
+
+class StgIo;
+class SvStream;
+
+SvStream& ReadClsId( SvStream&, ClsId& );
+SvStream& WriteClsId( SvStream&, const ClsId& );
+
+class StgHeader
+{
+    static const sal_uInt8 cFATPagesInHeader = 109;
+
+    sal_uInt8   m_cSignature[ 8 ] = {};       // 00 signature (see below)
+    ClsId       m_aClsId = {};                // 08 Class ID
+    sal_Int32   m_nVersion;                   // 18 version number
+    sal_uInt16  m_nByteOrder;                 // 1C Unicode byte order indicator
+    sal_Int16   m_nPageSize;                  // 1E 1 << nPageSize = block size
+    sal_Int16   m_nDataPageSize;              // 20 1 << this size == data block size
+    sal_uInt8   m_bDirty;                     // 22 internal dirty flag (should be
+                                            //    bool, but probably required to
+                                            //    be exactly one byte)
+    sal_uInt8   m_cReserved[ 9 ] = {};        // 23
+    sal_Int32   m_nFATSize;                   // 2C total number of FAT pages
+    sal_Int32   m_nTOCstrm;                   // 30 starting page for the TOC stream
+    sal_Int32   m_nReserved;                  // 34
+    sal_Int32   m_nThreshold;                 // 38 minimum file size for big data
+    sal_Int32   m_nDataFAT;                   // 3C page # of 1st data FAT block
+    sal_Int32   m_nDataFATSize;               // 40 # of data fat blocks
+    sal_Int32   m_nMasterChain;               // 44 chain to the next master block
+    sal_Int32   m_nMaster;                    // 48 # of additional master blocks
+    sal_Int32   m_nMasterFAT[ cFATPagesInHeader ] = {}; // 4C first [cFATPagesInHeader] master FAT pages
+public:
+    StgHeader();
+
+    void  Init();                       // initialize the header
+    bool      Load( StgIo& );
+    bool      Load( SvStream& );
+    bool      Store( StgIo& );
+    bool      Check();                      // check the signature and version
+    sal_Int32 GetTOCStart() const           { return m_nTOCstrm; }
+    void      SetTOCStart( sal_Int32 n );
+    sal_Int32 GetDataFATStart() const       { return m_nDataFAT; }
+    void      SetDataFATStart( sal_Int32 n );
+    sal_Int32 GetDataFATSize() const        { return m_nDataFATSize; }
+    void      SetDataFATSize( sal_Int32 n );
+    sal_Int32 GetThreshold() const          { return m_nThreshold; }
+    short     GetPageSize() const           { return m_nPageSize; }
+    short     GetDataPageSize() const       { return m_nDataPageSize; }
+    sal_Int32 GetFATSize() const            { return m_nFATSize; }
+    void      SetFATSize( sal_Int32 n );
+    sal_Int32 GetFATChain() const           { return m_nMasterChain; }
+    void      SetFATChain( sal_Int32 n );
+    sal_Int32 GetMasters() const            { return m_nMaster; }
+    void      SetMasters( sal_Int32 n );
+    static short GetFAT1Size()              { return cFATPagesInHeader; }
+    sal_Int32 GetFATPage( short ) const;
+    void      SetFATPage( short, sal_Int32 );
+};
+
+enum StgEntryType {                     // dir entry types:
+    STG_EMPTY     = 0,
+    STG_STORAGE   = 1,
+    STG_STREAM    = 2,
+    STG_ROOT      = 5
+};
+
+enum StgEntryRef {                      // reference blocks:
+    STG_LEFT      = 0,                  // left
+    STG_RIGHT     = 1,                  // right
+    STG_CHILD     = 2,                  // child
+    STG_DATA      = 3                   // data start
+};
+
+#define STGENTRY_SIZE 128
+
+//StructuredStorageDirectoryEntry
+class StgEntry
+{                        // directory entry
+    sal_Unicode m_nName[ 32 ];                // 00 name as WCHAR
+    sal_uInt16  m_nNameLen;                   // 40 size of name in bytes including 00H
+    sal_uInt8   m_cType;                      // 42 entry type
+    sal_uInt8   m_cFlags;                     // 43 0 or 1 (tree balance?)
+    sal_Int32   m_nLeft;                      // 44 left node entry
+    sal_Int32   m_nRight;                     // 48 right node entry
+    sal_Int32   m_nChild;                     // 4C 1st child entry if storage
+    ClsId       m_aClsId;                     // 50 class ID (optional)
+    sal_Int32   m_nFlags;                     // 60 state flags(?)
+    sal_Int32   m_nMtime[ 2 ];                // 64 modification time
+    sal_Int32   m_nAtime[ 2 ];                // 6C creation and access time
+    sal_Int32   m_nPage1;                     // 74 starting block (either direct or translated)
+    sal_Int32   m_nSize;                      // 78 file size
+    sal_Int32   m_nUnknown;                   // 7C unknown
+    OUString    m_aName;                      // Name as Compare String (ascii, upper)
+public:
+    void        Init();                     // initialize the data
+    void        SetName( const OUString& );   // store a name (ASCII, up to 32 chars)
+    void        GetName( OUString& rName ) const;
+                                        // fill in the name
+    sal_Int32   Compare( const StgEntry& ) const;   // compare two entries
+    bool        Load( const void* pBuffer, sal_uInt32 nBufSize, sal_uInt64 nUnderlyingStreamSize );
+    void        Store( void* );
+    StgEntryType GetType() const            { return static_cast<StgEntryType>(m_cType);  }
+    sal_Int32   GetStartPage() const        { return m_nPage1; }
+    void        SetType( StgEntryType t )   { m_cType = static_cast<sal_uInt8>(t); }
+    sal_Int32   GetSize() const             { return m_nSize; }
+    void        SetSize( sal_Int32 n )      { m_nSize = n; }
+    const ClsId& GetClassId() const         { return m_aClsId; }
+    void        SetClassId( const ClsId& );
+    sal_Int32   GetLeaf( StgEntryRef ) const;
+    void        SetLeaf( StgEntryRef, sal_Int32 );
+};
+
+
+#define STG_FREE    -1L                 // page is free
+#define STG_EOF     -2L                 // page is last page in chain
+#define STG_FAT     -3L                 // page is FAT page
+#define STG_MASTER  -4L                 // page is master FAT page
+
+#endif
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/sot/source/sdstor/stgio.cxx b/sot/source/sdstor/stgio.cxx
new file mode 100644
index 000000000..604d08282
--- /dev/null
+++ b/sot/source/sdstor/stgio.cxx
@@ -0,0 +1,400 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+
+#include "stgelem.hxx"
+#include "stgcache.hxx"
+#include "stgstrms.hxx"
+#include "stgdir.hxx"
+#include "stgio.hxx"
+#include <o3tl/safeint.hxx>
+#include <sal/log.hxx>
+
+#include <memory>
+#include <optional>
+
+///////////////////////////// class StgIo
+
+// This class holds the storage header and all internal streams.
+
+StgIo::StgIo()
+{
+    m_pTOC      = nullptr;
+    m_pDataFAT  = nullptr;
+    m_pDataStrm = nullptr;
+    m_pFAT      = nullptr;
+    m_bCopied   = false;
+}
+
+StgIo::~StgIo()
+{
+    delete m_pTOC;
+    delete m_pDataFAT;
+    delete m_pDataStrm;
+    delete m_pFAT;
+}
+
+// Load the header. Do not set an error code if the header is invalid.
+
+bool StgIo::Load()
+{
+    if( GetStrm() )
+    {
+        if( m_aHdr.Load( *this ) )
+        {
+            if( m_aHdr.Check() )
+                SetupStreams();
+            else
+                return false;
+        }
+        else
+            return false;
+    }
+    return Good();
+}
+
+// Set up an initial, empty storage
+
+bool StgIo::Init()
+{
+    m_aHdr.Init();
+    SetupStreams();
+    return CommitAll();
+}
+
+void StgIo::SetupStreams()
+{
+    delete m_pTOC;
+    delete m_pDataFAT;
+    delete m_pDataStrm;
+    delete m_pFAT;
+    m_pTOC      = nullptr;
+    m_pDataFAT  = nullptr;
+    m_pDataStrm = nullptr;
+    m_pFAT      = nullptr;
+    ResetError();
+
+    short nPhysPageSize = 1 << m_aHdr.GetPageSize();
+    SetPhysPageSize(nPhysPageSize);
+    sal_Int32 nFatStrmSize;
+    if (o3tl::checked_multiply<sal_Int32>(m_aHdr.GetFATSize(), nPhysPageSize, nFatStrmSize))
+    {
+        SAL_WARN("sot", "Error: " << m_aHdr.GetFATSize() << " * " << nPhysPageSize << " would overflow");
+        SetError(SVSTREAM_FILEFORMAT_ERROR);
+        m_pFAT = nullptr;
+        m_pTOC = nullptr;
+        return;
+    }
+
+    m_pFAT = new StgFATStrm(*this, nFatStrmSize);
+    m_pTOC = new StgDirStrm(*this);
+    if( GetError() )
+        return;
+
+    StgDirEntry* pRoot = m_pTOC->GetRoot();
+    if( pRoot )
+    {
+        m_pDataFAT = new StgDataStrm( *this, m_aHdr.GetDataFATStart(), -1 );
+        m_pDataStrm = new StgDataStrm( *this, *pRoot );
+        m_pDataFAT->SetIncrement( 1 << m_aHdr.GetPageSize() );
+        m_pDataStrm->SetIncrement( GetDataPageSize() );
+        m_pDataStrm->SetEntry( *pRoot );
+    }
+    else
+        SetError( SVSTREAM_FILEFORMAT_ERROR );
+}
+
+// get the logical data page size
+
+short StgIo::GetDataPageSize() const
+{
+    return 1 << m_aHdr.GetDataPageSize();
+}
+
+// Commit everything
+
+bool StgIo::CommitAll()
+{
+    // Store the data (all streams and the TOC)
+    if( m_pTOC && m_pTOC->Store() && m_pDataFAT )
+    {
+        if( Commit() )
+        {
+            m_aHdr.SetDataFATStart( m_pDataFAT->GetStart() );
+            m_aHdr.SetDataFATSize( m_pDataFAT->GetPages() );
+            m_aHdr.SetTOCStart( m_pTOC->GetStart() );
+            if( m_aHdr.Store( *this ) )
+            {
+                GetStrm()->Flush();
+                const ErrCode n = GetStrm()->GetError();
+                SetError( n );
+#ifdef DBG_UTIL
+                if( n==ERRCODE_NONE ) ValidateFATs();
+#endif
+                return n == ERRCODE_NONE;
+            }
+        }
+    }
+    SetError( SVSTREAM_WRITE_ERROR );
+    return false;
+}
+
+namespace {
+
+class EasyFat
+{
+    std::unique_ptr<sal_Int32[]> pFat;
+    std::unique_ptr<bool[]> pFree;
+    sal_Int32 nPages;
+    sal_Int32 nPageSize;
+
+public:
+    EasyFat( StgIo & rIo, StgStrm *pFatStream, sal_Int32 nPSize );
+
+    sal_Int32 GetPageSize() const { return nPageSize; }
+
+    FatError Mark( sal_Int32 nPage, sal_Int32 nCount, sal_Int32 nExpect );
+    bool HasUnrefChains() const;
+};
+
+}
+
+EasyFat::EasyFat( StgIo& rIo, StgStrm* pFatStream, sal_Int32 nPSize )
+   : nPages(pFatStream->GetSize() >> 2), nPageSize(nPSize)
+{
+    pFat.reset( new sal_Int32[ nPages ] );
+    pFree.reset( new bool[ nPages ] );
+
+    rtl::Reference< StgPage > pPage;
+    sal_Int32 nFatPageSize = (1 << rIo.m_aHdr.GetPageSize()) - 2;
+
+    for( sal_Int32 nPage = 0; nPage < nPages; nPage++ )
+    {
+        if( ! (nPage % nFatPageSize) )
+        {
+            pFatStream->Pos2Page( nPage << 2 );
+            sal_Int32 nPhysPage = pFatStream->GetPage();
+            pPage = rIo.Get( nPhysPage, true );
+        }
+
+        pFat[ nPage ] = StgCache::GetFromPage( pPage, short( nPage % nFatPageSize ) );
+        pFree[ nPage ] = true;
+    }
+}
+
+bool EasyFat::HasUnrefChains() const
+{
+    for( sal_Int32 nPage = 0; nPage < nPages; nPage++ )
+    {
+        if( pFree[ nPage ] && pFat[ nPage ] != -1 )
+            return true;
+    }
+    return false;
+}
+
+FatError EasyFat::Mark( sal_Int32 nPage, sal_Int32 nCount, sal_Int32 nExpect )
+{
+    if( nCount > 0 )
+    {
+        --nCount;
+        nCount /= GetPageSize();
+        ++nCount;
+    }
+
+    sal_Int32 nCurPage = nPage;
+    while( nCount != 0 )
+    {
+        if( nCurPage < 0 || nCurPage >= nPages )
+            return FatError::OutOfBounds;
+        pFree[ nCurPage ] = false;
+        nCurPage = pFat[ nCurPage ];
+        // stream too long
+        if( nCurPage != nExpect && nCount == 1 )
+            return FatError::WrongLength;
+        // stream too short
+        if( nCurPage == nExpect && nCount != 1 && nCount != -1 )
+            return FatError::WrongLength;
+        // last block for stream without length
+        if( nCurPage == nExpect && nCount == -1 )
+            nCount = 1;
+        if( nCount != -1 )
+            nCount--;
+    }
+    return FatError::Ok;
+}
+
+namespace {
+
+class Validator
+{
+    FatError nError;
+
+    EasyFat aSmallFat;
+    EasyFat aFat;
+
+    StgIo &rIo;
+
+    FatError ValidateMasterFATs();
+    FatError ValidateDirectoryEntries();
+    FatError FindUnrefedChains() const;
+    FatError MarkAll( StgDirEntry *pEntry );
+
+public:
+    explicit Validator( StgIo &rIo );
+    bool IsError() const { return nError != FatError::Ok; }
+};
+
+}
+
+Validator::Validator( StgIo &rIoP )
+    : aSmallFat( rIoP, rIoP.m_pDataFAT, 1 << rIoP.m_aHdr.GetDataPageSize() ),
+      aFat( rIoP, rIoP.m_pFAT, 1 << rIoP.m_aHdr.GetPageSize() ),
+      rIo( rIoP )
+{
+    FatError nErr = nError = FatError::Ok;
+
+    if( ( nErr = ValidateMasterFATs() ) != FatError::Ok )
+        nError = nErr;
+    else if(    ( nErr = ValidateDirectoryEntries() ) != FatError::Ok )
+        nError = nErr;
+    else if(    ( nErr = FindUnrefedChains()) != FatError::Ok )
+        nError = nErr;
+}
+
+FatError Validator::ValidateMasterFATs()
+{
+    sal_Int32 nCount = rIo.m_aHdr.GetFATSize();
+    FatError nErr;
+    if ( !rIo.m_pFAT )
+        return FatError::InMemoryError;
+
+    for( sal_Int32 i = 0; i < nCount; i++ )
+    {
+        if( ( nErr = aFat.Mark(rIo.m_pFAT->GetPage(i, false), aFat.GetPageSize(), -3 )) != FatError::Ok)
+            return nErr;
+    }
+    if( rIo.m_aHdr.GetMasters() )
+        if( ( nErr = aFat.Mark(rIo.m_aHdr.GetFATChain( ), aFat.GetPageSize(), -4 )) != FatError::Ok )
+            return nErr;
+
+    return FatError::Ok;
+}
+
+FatError Validator::MarkAll( StgDirEntry *pEntry )
+{
+    if ( !pEntry )
+        return FatError::InMemoryError;
+
+    StgIterator aIter( *pEntry );
+    FatError nErr = FatError::Ok;
+    for( StgDirEntry* p = aIter.First(); p ; p = aIter.Next() )
+    {
+        if( p->m_aEntry.GetType() == STG_STORAGE )
+        {
+            nErr = MarkAll( p );
+            if( nErr != FatError::Ok )
+                return nErr;
+        }
+        else
+        {
+            sal_Int32 nSize = p->m_aEntry.GetSize();
+            if( nSize < rIo.m_aHdr.GetThreshold()  )
+                nErr = aSmallFat.Mark( p->m_aEntry.GetStartPage(),nSize, -2 );
+            else
+                nErr = aFat.Mark( p->m_aEntry.GetStartPage(),nSize, -2 );
+            if( nErr != FatError::Ok )
+                return nErr;
+        }
+    }
+    return FatError::Ok;
+}
+
+FatError Validator::ValidateDirectoryEntries()
+{
+    if ( !rIo.m_pTOC )
+        return FatError::InMemoryError;
+
+    // Normal DirEntries
+    FatError nErr = MarkAll( rIo.m_pTOC->GetRoot() );
+    if( nErr != FatError::Ok )
+        return nErr;
+    // Small Data
+    nErr = aFat.Mark( rIo.m_pTOC->GetRoot()->m_aEntry.GetStartPage(),
+                 rIo.m_pTOC->GetRoot()->m_aEntry.GetSize(), -2 );
+    if( nErr != FatError::Ok )
+        return nErr;
+    // Small Data FAT
+    nErr = aFat.Mark(
+        rIo.m_aHdr.GetDataFATStart(),
+        rIo.m_aHdr.GetDataFATSize() * aFat.GetPageSize(), -2 );
+    if( nErr != FatError::Ok )
+        return nErr;
+    // TOC
+    nErr = aFat.Mark(
+        rIo.m_aHdr.GetTOCStart(), -1, -2 );
+    return nErr;
+}
+
+FatError Validator::FindUnrefedChains() const
+{
+    if( aSmallFat.HasUnrefChains() ||
+        aFat.HasUnrefChains() )
+        return FatError::UnrefChain;
+    else
+        return FatError::Ok;
+}
+
+FatError StgIo::ValidateFATs()
+{
+    if( m_bFile )
+    {
+        std::optional<Validator> pV( *this );
+        bool bRet1 = !pV->IsError(), bRet2 = true ;
+        pV.reset();
+
+        SvFileStream *pFileStrm = static_cast<SvFileStream *>( GetStrm() );
+        if ( !pFileStrm )
+            return FatError::InMemoryError;
+
+        StgIo aIo;
+        if( aIo.Open( pFileStrm->GetFileName(),
+                      StreamMode::READ | StreamMode::SHARE_DENYNONE) &&
+            aIo.Load() )
+        {
+            pV.emplace( aIo );
+            bRet2 = !pV->IsError();
+            pV.reset();
+        }
+
+        FatError nErr;
+        if( bRet1 != bRet2 )
+            nErr = bRet1 ? FatError::OnFileError : FatError::InMemoryError;
+        else nErr = bRet1 ? FatError::Ok : FatError::BothError;
+        if( nErr != FatError::Ok && !m_bCopied )
+        {
+            m_bCopied = true;
+        }
+//      DBG_ASSERT( nErr == FatError::Ok ,"Storage broken");
+        return nErr;
+    }
+//  OSL_FAIL("Do not validate (no FileStorage)");
+    return FatError::Ok;
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/sot/source/sdstor/stgio.hxx b/sot/source/sdstor/stgio.hxx
new file mode 100644
index 000000000..7ed5917ac
--- /dev/null
+++ b/sot/source/sdstor/stgio.hxx
@@ -0,0 +1,63 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+#ifndef INCLUDED_SOT_SOURCE_SDSTOR_STGIO_HXX
+#define INCLUDED_SOT_SOURCE_SDSTOR_STGIO_HXX
+
+#include "stgcache.hxx"
+#include "stgelem.hxx"
+
+class StgFATStrm;
+class StgDataStrm;
+class StgDirStrm;
+
+enum class FatError
+{
+    Ok,
+    WrongLength,
+    UnrefChain,
+    OutOfBounds,
+
+    InMemoryError,
+    OnFileError,
+    BothError
+};
+
+class StgIo : public StgCache {
+    void SetupStreams();            // load all internal streams
+    bool         m_bCopied;
+public:
+    StgIo();
+   ~StgIo();
+    StgHeader    m_aHdr;              // storage file header
+    StgFATStrm*  m_pFAT;              // FAT stream
+    StgDirStrm*  m_pTOC;              // TOC stream
+    StgDataStrm* m_pDataFAT;          // small data FAT stream
+    StgDataStrm* m_pDataStrm;         // small data stream
+    short        GetDataPageSize() const; // get the logical data page size
+    bool Load();                    // load a storage file
+    bool Init();                    // set up an empty file
+    bool CommitAll();               // commit everything (root commit)
+
+    FatError ValidateFATs( );
+};
+
+#endif
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/sot/source/sdstor/stgole.cxx b/sot/source/sdstor/stgole.cxx
new file mode 100644
index 000000000..ac23f7a14
--- /dev/null
+++ b/sot/source/sdstor/stgole.cxx
@@ -0,0 +1,180 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+#include <memory>
+#include <algorithm>
+
+#include "stgelem.hxx"
+#include "stgole.hxx"
+#include <o3tl/safeint.hxx>
+#include <sot/storinfo.hxx>
+
+///////////////////////// class StgInternalStream
+
+StgInternalStream::StgInternalStream( BaseStorage& rStg, const OUString& rName, bool bWr )
+{
+    m_isWritable = true;
+    StreamMode nMode = bWr
+                 ? StreamMode::WRITE | StreamMode::SHARE_DENYALL
+                 : StreamMode::READ | StreamMode::SHARE_DENYWRITE | StreamMode::NOCREATE;
+    m_pStrm.reset( rStg.OpenStream( rName, nMode ) );
+
+    // set the error code right here in the stream
+    SetError( rStg.GetError() );
+    SetBufferSize( 1024 );
+}
+
+StgInternalStream::~StgInternalStream()
+{
+}
+
+std::size_t StgInternalStream::GetData(void* pData, std::size_t nSize)
+{
+    if( m_pStrm )
+    {
+        nSize = m_pStrm->Read( pData, nSize );
+        SetError( m_pStrm->GetError() );
+        return nSize;
+    }
+    else
+        return 0;
+}
+
+std::size_t StgInternalStream::PutData(const void* pData, std::size_t nSize)
+{
+    if( m_pStrm )
+    {
+        nSize = m_pStrm->Write( pData, nSize );
+        SetError( m_pStrm->GetError() );
+        return nSize;
+    }
+    else
+        return 0;
+}
+
+sal_uInt64 StgInternalStream::SeekPos(sal_uInt64 const nPos)
+{
+    return m_pStrm ? m_pStrm->Seek( nPos ) : 0;
+}
+
+void StgInternalStream::FlushData()
+{
+    if( m_pStrm )
+    {
+        m_pStrm->Flush();
+        SetError( m_pStrm->GetError() );
+    }
+}
+
+void StgInternalStream::Commit()
+{
+    Flush();
+    m_pStrm->Commit();
+}
+
+///////////////////////// class StgCompObjStream
+
+StgCompObjStream::StgCompObjStream( BaseStorage& rStg, bool bWr )
+    : StgInternalStream( rStg, "\1CompObj", bWr )
+{
+}
+
+bool StgCompObjStream::Load()
+{
+    memset( &m_aClsId, 0, sizeof( ClsId ) );
+    m_nCbFormat = SotClipboardFormatId::NONE;
+    m_aUserName.clear();
+    if( GetError() != ERRCODE_NONE )
+        return false;
+    Seek( 8 );     // skip the first part
+    sal_Int32 nMarker = 0;
+    ReadInt32( nMarker );
+    if( nMarker == -1 )
+    {
+        ReadClsId( *this, m_aClsId );
+        sal_Int32 nLen1 = 0;
+        ReadInt32( nLen1 );
+        if ( nLen1 > 0 )
+        {
+            // higher bits are ignored
+            sal_Int32 nStrLen = ::std::min( nLen1, sal_Int32(0xFFFE) );
+
+            std::unique_ptr<char[]> p(new char[ nStrLen+1 ]);
+            p[nStrLen] = 0;
+            if (ReadBytes( p.get(), nStrLen ) == o3tl::make_unsigned(nStrLen))
+            {
+                //The encoding here is "ANSI", which is pretty useless seeing as
+                //the actual codepage used doesn't seem to be specified/stored
+                //anywhere :-(. Might as well pick 1252 and be consistent on
+                //all platforms and envs
+                //https://bz.apache.org/ooo/attachment.cgi?id=68668
+                //for a good edge-case example
+                m_aUserName = OUString(p.get(), nStrLen, RTL_TEXTENCODING_MS_1252);
+                m_nCbFormat = ReadClipboardFormat( *this );
+            }
+            else
+                SetError( SVSTREAM_GENERALERROR );
+        }
+    }
+    return GetError() == ERRCODE_NONE;
+}
+
+bool StgCompObjStream::Store()
+{
+    if( GetError() != ERRCODE_NONE )
+        return false;
+    Seek( 0 );
+    OString aAsciiUserName(OUStringToOString(m_aUserName, RTL_TEXTENCODING_MS_1252));
+    WriteInt16( 1 );          // Version?
+    WriteInt16( -2 );                     // 0xFFFE = Byte Order Indicator
+    WriteInt32( 0x0A03 );         // Windows 3.10
+    WriteInt32( -1 );
+    WriteClsId( *this, m_aClsId );             // Class ID
+    WriteInt32( aAsciiUserName.getLength() + 1 );
+    WriteOString( aAsciiUserName );
+    WriteUChar( 0 );             // string terminator
+    WriteClipboardFormat( *this, m_nCbFormat );
+    WriteInt32( 0 );             // terminator
+    Commit();
+    return GetError() == ERRCODE_NONE;
+}
+
+/////////////////////////// class StgOleStream
+
+StgOleStream::StgOleStream( BaseStorage& rStg )
+    : StgInternalStream( rStg, "\1Ole", true )
+{
+}
+
+bool StgOleStream::Store()
+{
+    if( GetError() != ERRCODE_NONE )
+        return false;
+
+    Seek( 0 );
+    WriteInt32( 0x02000001 );         // OLE version, format
+    WriteInt32( 0 );             // Object flags
+    WriteInt32( 0 );                  // Update Options
+    WriteInt32( 0 );                  // reserved
+    WriteInt32( 0 );                 // Moniker 1
+    Commit();
+    return GetError() == ERRCODE_NONE;
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/sot/source/sdstor/stgole.hxx b/sot/source/sdstor/stgole.hxx
new file mode 100644
index 000000000..899b07fcd
--- /dev/null
+++ b/sot/source/sdstor/stgole.hxx
@@ -0,0 +1,67 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+#ifndef INCLUDED_SOT_SOURCE_SDSTOR_STGOLE_HXX
+#define INCLUDED_SOT_SOURCE_SDSTOR_STGOLE_HXX
+
+#include <memory>
+
+#include <sot/stg.hxx>
+
+class StgInternalStream : public SvStream
+{
+    std::unique_ptr<BaseStorageStream> m_pStrm;
+    virtual std::size_t GetData(void* pData, std::size_t nSize) override;
+    virtual std::size_t PutData(const void* pData, std::size_t nSize) override;
+    virtual sal_uInt64 SeekPos( sal_uInt64 nPos ) override;
+    virtual void      FlushData() override;
+public:
+    StgInternalStream( BaseStorage&, const OUString&, bool );
+   virtual ~StgInternalStream() override;
+    void Commit();
+};
+
+// standard stream "\1CompObj"
+
+class StgCompObjStream : public StgInternalStream
+{
+    ClsId       m_aClsId = {};
+    OUString    m_aUserName;
+    SotClipboardFormatId m_nCbFormat = SotClipboardFormatId::NONE;
+public:
+    StgCompObjStream( BaseStorage&, bool );
+    ClsId&     GetClsId()    { return m_aClsId;    }
+    OUString&  GetUserName() { return m_aUserName; }
+    SotClipboardFormatId& GetCbFormat() { return m_nCbFormat; }
+    bool       Load();
+    bool       Store();
+};
+
+// standard stream "\1Ole"
+
+class StgOleStream : public StgInternalStream
+{
+public:
+    explicit StgOleStream( BaseStorage& );
+    bool Store();
+};
+
+#endif
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/sot/source/sdstor/stgstrms.cxx b/sot/source/sdstor/stgstrms.cxx
new file mode 100644
index 000000000..717e4e7d1
--- /dev/null
+++ b/sot/source/sdstor/stgstrms.cxx
@@ -0,0 +1,1356 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+#include <algorithm>
+
+#include <string.h>
+#include <sal/log.hxx>
+#include <o3tl/safeint.hxx>
+#include <osl/file.hxx>
+#include <unotools/tempfile.hxx>
+
+#include "stgelem.hxx"
+#include "stgcache.hxx"
+#include "stgstrms.hxx"
+#include "stgdir.hxx"
+#include "stgio.hxx"
+#include <memory>
+
+///////////////////////////// class StgFAT
+
+// The FAT class performs FAT operations on an underlying storage stream.
+// This stream is either the master FAT stream (m == true ) or a normal
+// storage stream, which then holds the FAT for small data allocations.
+
+StgFAT::StgFAT( StgStrm& r, bool m ) : m_rStrm( r )
+{
+    m_bPhys   = m;
+    m_nPageSize = m_rStrm.GetIo().GetPhysPageSize();
+    m_nEntries  = m_nPageSize >> 2;
+    m_nOffset   = 0;
+    m_nMaxPage  = 0;
+    m_nLimit    = 0;
+}
+
+// Retrieve the physical page for a given byte offset.
+
+rtl::Reference< StgPage > StgFAT::GetPhysPage( sal_Int32 nByteOff )
+{
+    rtl::Reference< StgPage > pPg;
+    // Position within the underlying stream
+    // use the Pos2Page() method of the stream
+    if( m_rStrm.Pos2Page( nByteOff ) )
+    {
+        m_nOffset = m_rStrm.GetOffset();
+        sal_Int32 nPhysPage = m_rStrm.GetPage();
+        // get the physical page (must be present)
+        pPg = m_rStrm.GetIo().Get( nPhysPage, true );
+    }
+    return pPg;
+}
+
+// Get the follow page for a certain FAT page.
+
+sal_Int32 StgFAT::GetNextPage( sal_Int32 nPg )
+{
+    if (nPg >= 0)
+    {
+        if (nPg > (SAL_MAX_INT32 >> 2))
+            return STG_EOF;
+        rtl::Reference< StgPage > pPg = GetPhysPage( nPg << 2 );
+        nPg = pPg.is() ? StgCache::GetFromPage( pPg, m_nOffset >> 2 ) : STG_EOF;
+    }
+    return nPg;
+}
+
+// Find the best fit block for the given size. Return
+// the starting block and its size or STG_EOF and 0.
+// nLastPage is a stopper which tells the current
+// underlying stream size. It is treated as a recommendation
+// to abort the search to inhibit excessive file growth.
+
+sal_Int32 StgFAT::FindBlock( sal_Int32& nPgs )
+{
+    sal_Int32 nMinStart = STG_EOF, nMinLen = 0;
+    sal_Int32 nMaxStart = STG_EOF, nMaxLen = 0x7FFFFFFFL;
+    sal_Int32 nTmpStart = STG_EOF, nTmpLen = 0;
+    sal_Int32 nPages    = m_rStrm.GetSize() >> 2;
+    bool bFound     = false;
+    rtl::Reference< StgPage > pPg;
+    short nEntry = 0;
+    for( sal_Int32 i = 0; i < nPages; i++, nEntry++ )
+    {
+        if( !( nEntry % m_nEntries ) )
+        {
+            // load the next page for that stream
+            nEntry = 0;
+            pPg = GetPhysPage( i << 2 );
+            if( !pPg.is() )
+                return STG_EOF;
+        }
+        sal_Int32 nCur = StgCache::GetFromPage( pPg, nEntry );
+        if( nCur == STG_FREE )
+        {
+            // count the size of this area
+            if( nTmpLen )
+                nTmpLen++;
+            else
+            {
+                nTmpStart = i;
+                nTmpLen   = 1;
+            }
+            if( nTmpLen == nPgs
+             // If we already did find a block, stop when reaching the limit
+             || ( bFound && ( nEntry >= m_nLimit ) ) )
+                break;
+        }
+        else if( nTmpLen )
+        {
+            if( nTmpLen > nPgs && nTmpLen < nMaxLen )
+            {
+                // block > requested size
+                nMaxLen = nTmpLen;
+                nMaxStart = nTmpStart;
+                bFound = true;
+            }
+            else if( nTmpLen >= nMinLen )
+            {
+                // block < requested size
+                nMinLen = nTmpLen;
+                nMinStart = nTmpStart;
+                bFound = true;
+                if( nTmpLen == nPgs )
+                    break;
+            }
+            nTmpStart = STG_EOF;
+            nTmpLen   = 0;
+        }
+    }
+    // Determine which block to use.
+    if( nTmpLen )
+    {
+        if( nTmpLen > nPgs  && nTmpLen < nMaxLen )
+        {
+            // block > requested size
+            nMaxLen = nTmpLen;
+            nMaxStart = nTmpStart;
+        }
+        else if( nTmpLen >= nMinLen )
+        {
+            // block < requested size
+            nMinLen = nTmpLen;
+            nMinStart = nTmpStart;
+        }
+    }
+    if( nMinStart != STG_EOF && nMaxStart != STG_EOF )
+    {
+        // two areas found; return the best fit area
+        sal_Int32 nMinDiff = nPgs - nMinLen;
+        sal_Int32 nMaxDiff = nMaxLen - nPgs;
+        if( nMinDiff > nMaxDiff )
+            nMinStart = STG_EOF;
+    }
+    if( nMinStart != STG_EOF )
+    {
+        nPgs = nMinLen; return nMinStart;
+    }
+    else
+    {
+        return nMaxStart;
+    }
+}
+
+// Set up the consecutive chain for a given block.
+
+bool StgFAT::MakeChain( sal_Int32 nStart, sal_Int32 nPgs )
+{
+    sal_Int32 nPos = nStart << 2;
+    rtl::Reference< StgPage > pPg = GetPhysPage( nPos );
+    if( !pPg.is() || !nPgs )
+        return false;
+    while( --nPgs )
+    {
+        if( m_nOffset >= m_nPageSize )
+        {
+            pPg = GetPhysPage( nPos );
+            if( !pPg.is() )
+                return false;
+        }
+        m_rStrm.GetIo().SetToPage( pPg, m_nOffset >> 2, ++nStart );
+        m_nOffset += 4;
+        nPos += 4;
+    }
+    if( m_nOffset >= m_nPageSize )
+    {
+        pPg = GetPhysPage( nPos );
+        if( !pPg.is() )
+            return false;
+    }
+    m_rStrm.GetIo().SetToPage( pPg, m_nOffset >> 2, STG_EOF );
+    return true;
+}
+
+// Allocate a block of data from the given page number on.
+// It the page number is != STG_EOF, chain the block.
+
+sal_Int32 StgFAT::AllocPages( sal_Int32 nBgn, sal_Int32 nPgs )
+{
+    sal_Int32 nOrig = nBgn;
+    sal_Int32 nLast = nBgn;
+    sal_Int32 nBegin = STG_EOF;
+    sal_Int32 nAlloc;
+    sal_Int32 nPages = m_rStrm.GetSize() >> 2;
+    short nPasses = 0;
+    // allow for two passes
+    while( nPasses < 2 )
+    {
+        // try to satisfy the request from the pool of free pages
+        while( nPgs )
+        {
+            nAlloc = nPgs;
+            nBegin = FindBlock( nAlloc );
+            // no more blocks left in present alloc chain
+            if( nBegin == STG_EOF )
+                break;
+            if( ( nBegin + nAlloc ) > m_nMaxPage )
+                m_nMaxPage = nBegin + nAlloc;
+            if( !MakeChain( nBegin, nAlloc ) )
+                return STG_EOF;
+            if( nOrig == STG_EOF )
+                nOrig = nBegin;
+            else
+            {
+                // Patch the chain
+                rtl::Reference< StgPage > pPg = GetPhysPage( nLast << 2 );
+                if( !pPg.is() )
+                    return STG_EOF;
+                m_rStrm.GetIo().SetToPage( pPg, m_nOffset >> 2, nBegin );
+            }
+            nLast = nBegin + nAlloc - 1;
+            nPgs -= nAlloc;
+        }
+        if( nPgs && !nPasses )
+        {
+            // we need new, fresh space, so allocate and retry
+            if( !m_rStrm.SetSize( ( nPages + nPgs ) << 2 ) )
+                return STG_EOF;
+            if( !m_bPhys && !InitNew( nPages ) )
+                return 0;
+                    // FIXME: this was originally "FALSE", whether or not that
+                    // makes sense (or should be STG_EOF instead, say?)
+            nPages = m_rStrm.GetSize() >> 2;
+            nPasses++;
+        }
+        else
+            break;
+    }
+    // now we should have a chain for the complete block
+    if( nBegin == STG_EOF || nPgs )
+    {
+        m_rStrm.GetIo().SetError( SVSTREAM_FILEFORMAT_ERROR );
+        return STG_EOF; // bad structure
+    }
+    return nOrig;
+}
+
+// Initialize newly allocated pages for a standard FAT stream
+// It can be assumed that the stream size is always on
+// a page boundary
+
+bool StgFAT::InitNew( sal_Int32 nPage1 )
+{
+    sal_Int32 n = ( ( m_rStrm.GetSize() >> 2 ) - nPage1 ) / m_nEntries;
+    if ( n > 0 )
+    {
+        while( n-- )
+        {
+            rtl::Reference< StgPage > pPg;
+            // Position within the underlying stream
+            // use the Pos2Page() method of the stream
+            m_rStrm.Pos2Page( nPage1 << 2 );
+            // Initialize the page
+            pPg = m_rStrm.GetIo().Copy( m_rStrm.GetPage() );
+            if ( !pPg.is() )
+                return false;
+            for( short i = 0; i < m_nEntries; i++ )
+                m_rStrm.GetIo().SetToPage( pPg, i, STG_FREE );
+            nPage1++;
+        }
+    }
+    return true;
+}
+
+// Release a chain
+
+bool StgFAT::FreePages( sal_Int32 nStart, bool bAll )
+{
+    while( nStart >= 0 )
+    {
+        rtl::Reference< StgPage > pPg = GetPhysPage( nStart << 2 );
+        if( !pPg.is() )
+            return false;
+        nStart = StgCache::GetFromPage( pPg, m_nOffset >> 2 );
+        // The first released page is either set to EOF or FREE
+        m_rStrm.GetIo().SetToPage( pPg, m_nOffset >> 2, bAll ? STG_FREE : STG_EOF );
+        bAll = true;
+    }
+    return true;
+}
+
+///////////////////////////// class StgStrm
+
+// The base stream class provides basic functionality for seeking
+// and accessing the data on a physical basis. It uses the built-in
+// FAT class for the page allocations.
+
+StgStrm::StgStrm( StgIo& r )
+    : m_nPos(0),
+      m_bBytePosValid(true),
+      m_rIo(r),
+      m_pEntry(nullptr),
+      m_nStart(STG_EOF),
+      m_nSize(0),
+      m_nPage(STG_EOF),
+      m_nOffset(0),
+      m_nPageSize(m_rIo.GetPhysPageSize())
+{
+}
+
+StgStrm::~StgStrm()
+{
+}
+
+// Attach the stream to the given entry.
+
+void StgStrm::SetEntry( StgDirEntry& r )
+{
+    r.m_aEntry.SetLeaf( STG_DATA, m_nStart );
+    r.m_aEntry.SetSize( m_nSize );
+    m_pEntry = &r;
+    r.SetDirty();
+}
+
+/*
+ * The page chain, is basically a singly linked list of slots each
+ * point to the next page. Instead of traversing the file structure
+ * for this each time build a simple flat in-memory vector list
+ * of pages.
+ */
+sal_Int32 StgStrm::scanBuildPageChainCache()
+{
+    if (m_nSize > 0)
+    {
+        m_aPagesCache.reserve(m_nSize/m_nPageSize);
+        m_aUsedPageNumbers.reserve(m_nSize/m_nPageSize);
+    }
+
+    bool bError = false;
+    sal_Int32 nBgn = m_nStart;
+    sal_Int32 nOptSize = 0;
+
+    // Track already scanned PageNumbers here and use them to
+    // see if an  already counted page is re-visited
+    while( nBgn >= 0 && !bError )
+    {
+        m_aPagesCache.push_back(nBgn);
+        nBgn = m_pFat->GetNextPage( nBgn );
+
+        //returned second is false if it already exists
+        if (!m_aUsedPageNumbers.insert(nBgn).second)
+        {
+            SAL_WARN ("sot", "Error: page number " << nBgn << " already in chain for stream");
+            bError = true;
+        }
+
+        nOptSize += m_nPageSize;
+    }
+    if (bError)
+    {
+        SAL_WARN("sot", "returning wrong format error");
+        m_rIo.SetError( ERRCODE_IO_WRONGFORMAT );
+        m_aPagesCache.clear();
+        m_aUsedPageNumbers.clear();
+    }
+    return nOptSize;
+}
+
+// Compute page number and offset for the given byte position.
+// If the position is behind the size, set the stream right
+// behind the EOF.
+bool StgStrm::Pos2Page( sal_Int32 nBytePos )
+{
+    if ( !m_pFat )
+        return false;
+
+    // Values < 0 seek to the end
+    if( nBytePos < 0 || nBytePos >= m_nSize )
+        nBytePos = m_nSize;
+    // Adjust the position back to offset 0
+    m_nPos -= m_nOffset;
+    sal_Int32 nMask = ~( m_nPageSize - 1 );
+    sal_Int32 nOld = m_nPos & nMask;
+    sal_Int32 nNew = nBytePos & nMask;
+    m_nOffset = static_cast<short>( nBytePos & ~nMask );
+    m_nPos = nBytePos;
+    if (nOld == nNew)
+        return m_bBytePosValid;
+
+    // See fdo#47644 for a .doc with a vast amount of pages where seeking around the
+    // document takes a colossal amount of time
+
+    // Please Note: we build the pagescache incrementally as we go if necessary,
+    // so that a corrupted FAT doesn't poison the stream state for earlier reads
+    size_t nIdx = nNew / m_nPageSize;
+    if( nIdx >= m_aPagesCache.size() )
+    {
+        // Extend the FAT cache ! ...
+        size_t nToAdd = nIdx + 1;
+
+        if (m_aPagesCache.empty())
+        {
+            m_aPagesCache.push_back( m_nStart );
+            assert(m_aUsedPageNumbers.empty());
+            m_aUsedPageNumbers.insert(m_nStart);
+        }
+
+        nToAdd -= m_aPagesCache.size();
+
+        sal_Int32 nBgn = m_aPagesCache.back();
+
+        // Start adding pages while we can
+        while (nToAdd > 0 && nBgn >= 0)
+        {
+            sal_Int32 nOldBgn = nBgn;
+            nBgn = m_pFat->GetNextPage(nOldBgn);
+            if( nBgn >= 0 )
+            {
+                //returned second is false if it already exists
+                if (!m_aUsedPageNumbers.insert(nBgn).second)
+                {
+                    SAL_WARN ("sot", "Error: page number " << nBgn << " already in chain for stream");
+                    break;
+                }
+
+                //very much the normal case
+                m_aPagesCache.push_back(nBgn);
+                --nToAdd;
+            }
+        }
+    }
+
+    if ( nIdx > m_aPagesCache.size() )
+    {
+        SAL_WARN("sot", "seek to index " << nIdx <<
+                 " beyond page cache size " << m_aPagesCache.size());
+        // fdo#84229 - handle seek to end and back as eg. XclImpStream expects
+        m_nPage = STG_EOF;
+        m_nOffset = 0;
+        // Intriguingly in the past we didn't reset nPos to match the real
+        // length of the stream thus:
+        //   nIdx = m_aPagesCache.size();
+        //   nPos = nPageSize * nIdx;
+        // so retain this behavior for now.
+        m_bBytePosValid = false;
+        return false;
+    }
+
+    // special case: seek to 1st byte of new, unallocated page
+    // (in case the file size is a multiple of the page size)
+    if( nBytePos == m_nSize && !m_nOffset && nIdx > 0 && nIdx == m_aPagesCache.size() )
+    {
+        nIdx--;
+        m_nOffset = m_nPageSize;
+    }
+    else if ( nIdx == m_aPagesCache.size() )
+    {
+        m_nPage = STG_EOF;
+        m_bBytePosValid = false;
+        return false;
+    }
+
+    m_nPage = m_aPagesCache[ nIdx ];
+
+    m_bBytePosValid = m_nPage >= 0;
+    return m_bBytePosValid;
+}
+
+// Copy an entire stream. Both streams are allocated in the FAT.
+// The target stream is this stream.
+
+bool StgStrm::Copy( sal_Int32 nFrom, sal_Int32 nBytes )
+{
+    if ( !m_pFat )
+        return false;
+
+    m_aPagesCache.clear();
+    m_aUsedPageNumbers.clear();
+
+    sal_Int32 nTo = m_nStart;
+    sal_Int32 nPgs = ( nBytes + m_nPageSize - 1 ) / m_nPageSize;
+    while( nPgs-- )
+    {
+        if( nTo < 0 )
+        {
+            m_rIo.SetError( SVSTREAM_FILEFORMAT_ERROR );
+            return false;
+        }
+        m_rIo.Copy( nTo, nFrom );
+        if( nFrom >= 0 )
+        {
+            nFrom = m_pFat->GetNextPage( nFrom );
+            if( nFrom < 0 )
+            {
+                m_rIo.SetError( SVSTREAM_FILEFORMAT_ERROR );
+                return false;
+            }
+        }
+        nTo = m_pFat->GetNextPage( nTo );
+    }
+    return true;
+}
+
+bool StgStrm::SetSize( sal_Int32 nBytes )
+{
+    if ( nBytes < 0 || !m_pFat )
+        return false;
+
+    m_aPagesCache.clear();
+    m_aUsedPageNumbers.clear();
+
+    // round up to page size
+    sal_Int32 nOld = ( ( m_nSize + m_nPageSize - 1 ) / m_nPageSize ) * m_nPageSize;
+    sal_Int32 nNew = ( ( nBytes + m_nPageSize - 1 ) / m_nPageSize ) * m_nPageSize;
+    if( nNew > nOld )
+    {
+        if( !Pos2Page( m_nSize ) )
+            return false;
+        sal_Int32 nBgn = m_pFat->AllocPages( m_nPage, ( nNew - nOld ) / m_nPageSize );
+        if( nBgn == STG_EOF )
+            return false;
+        if( m_nStart == STG_EOF )
+            m_nStart = m_nPage = nBgn;
+    }
+    else if( nNew < nOld )
+    {
+        bool bAll = ( nBytes == 0 );
+        if( !Pos2Page( nBytes ) || !m_pFat->FreePages( m_nPage, bAll ) )
+            return false;
+        if( bAll )
+            m_nStart = m_nPage = STG_EOF;
+    }
+    if( m_pEntry )
+    {
+        // change the dir entry?
+        if( !m_nSize || !nBytes )
+            m_pEntry->m_aEntry.SetLeaf( STG_DATA, m_nStart );
+        m_pEntry->m_aEntry.SetSize( nBytes );
+        m_pEntry->SetDirty();
+    }
+    m_nSize = nBytes;
+    m_pFat->SetLimit( GetPages() );
+    return true;
+}
+
+// Return the # of allocated pages
+
+
+//////////////////////////// class StgFATStrm
+
+// The FAT stream class provides physical access to the master FAT.
+// Since this access is implemented as a StgStrm, we can use the
+// FAT allocator.
+
+StgFATStrm::StgFATStrm(StgIo& r, sal_Int32 nFatStrmSize) : StgStrm( r )
+{
+    m_pFat.reset( new StgFAT( *this, true ) );
+    m_nSize = nFatStrmSize;
+}
+
+bool StgFATStrm::Pos2Page( sal_Int32 nBytePos )
+{
+    // Values < 0 seek to the end
+    if( nBytePos < 0 || nBytePos >= m_nSize  )
+        nBytePos = m_nSize ? m_nSize - 1 : 0;
+    m_nPage   = nBytePos / m_nPageSize;
+    m_nOffset = static_cast<short>( nBytePos % m_nPageSize );
+    m_nPage   = GetPage(m_nPage, false);
+    bool bValid = m_nPage >= 0;
+    SetPos(nBytePos, bValid);
+    return bValid;
+}
+
+// Get the page number entry for the given page offset.
+
+sal_Int32 StgFATStrm::GetPage(sal_Int32 nOff, bool bMake, sal_uInt16 *pnMasterAlloc)
+{
+    OSL_ENSURE( nOff >= 0, "The offset may not be negative!" );
+    if( pnMasterAlloc ) *pnMasterAlloc = 0;
+    if( nOff < StgHeader::GetFAT1Size() )
+        return m_rIo.m_aHdr.GetFATPage( nOff );
+    sal_Int32 nMaxPage = m_nSize >> 2;
+    nOff = nOff - StgHeader::GetFAT1Size();
+    // number of master pages that we need to iterate through
+    sal_uInt16 nMasterCount =  ( m_nPageSize >> 2 ) - 1;
+    sal_uInt16 nBlocks = nOff / nMasterCount;
+    // offset in the last master page
+    nOff = nOff % nMasterCount;
+
+    rtl::Reference< StgPage > pOldPage;
+    rtl::Reference< StgPage > pMaster;
+    sal_Int32 nFAT = m_rIo.m_aHdr.GetFATChain();
+    for( sal_uInt16 nCount = 0; nCount <= nBlocks; nCount++ )
+    {
+        if( nFAT == STG_EOF || nFAT == STG_FREE )
+        {
+            if( bMake )
+            {
+                m_aPagesCache.clear();
+                m_aUsedPageNumbers.clear();
+
+                // create a new master page
+                nFAT = nMaxPage++;
+                pMaster = m_rIo.Copy( nFAT );
+                if ( pMaster.is() )
+                {
+                    for( short k = 0; k < static_cast<short>( m_nPageSize >> 2 ); k++ )
+                        m_rIo.SetToPage( pMaster, k, STG_FREE );
+                    // chaining
+                    if( !pOldPage.is() )
+                        m_rIo.m_aHdr.SetFATChain( nFAT );
+                    else
+                        m_rIo.SetToPage( pOldPage, nMasterCount, nFAT );
+                    if( nMaxPage >= m_rIo.GetPhysPages() )
+                        if( !m_rIo.SetSize( nMaxPage ) )
+                            return STG_EOF;
+                    // mark the page as used
+                    // make space for Masterpage
+                    if( !pnMasterAlloc ) // create space oneself
+                    {
+                        if( !Pos2Page( nFAT << 2 ) )
+                            return STG_EOF;
+                        rtl::Reference< StgPage > pPg = m_rIo.Get( m_nPage, true );
+                        if( !pPg.is() )
+                            return STG_EOF;
+                        m_rIo.SetToPage( pPg, m_nOffset >> 2, STG_MASTER );
+                    }
+                    else
+                        (*pnMasterAlloc)++;
+                    m_rIo.m_aHdr.SetMasters( nCount + 1 );
+                    pOldPage = pMaster;
+                }
+            }
+        }
+        else
+        {
+            pMaster = m_rIo.Get( nFAT, true );
+            if ( pMaster.is() )
+            {
+                nFAT = StgCache::GetFromPage( pMaster, nMasterCount );
+                pOldPage = pMaster;
+            }
+        }
+    }
+    if( pMaster.is() )
+        return StgCache::GetFromPage( pMaster, nOff );
+    m_rIo.SetError( SVSTREAM_GENERALERROR );
+    return STG_EOF;
+}
+
+
+// Set the page number entry for the given page offset.
+
+bool StgFATStrm::SetPage( short nOff, sal_Int32 nNewPage )
+{
+    OSL_ENSURE( nOff >= 0, "The offset may not be negative!" );
+    m_aPagesCache.clear();
+    m_aUsedPageNumbers.clear();
+
+    bool bRes = true;
+    if( nOff < StgHeader::GetFAT1Size() )
+        m_rIo.m_aHdr.SetFATPage( nOff, nNewPage );
+    else
+    {
+        nOff = nOff - StgHeader::GetFAT1Size();
+        // number of master pages that we need to iterate through
+        sal_uInt16 nMasterCount =  ( m_nPageSize >> 2 ) - 1;
+        sal_uInt16 nBlocks = nOff / nMasterCount;
+        // offset in the last master page
+        nOff = nOff % nMasterCount;
+
+        rtl::Reference< StgPage > pMaster;
+        sal_Int32 nFAT = m_rIo.m_aHdr.GetFATChain();
+        for( sal_uInt16 nCount = 0; nCount <= nBlocks; nCount++ )
+        {
+            if( nFAT == STG_EOF || nFAT == STG_FREE )
+            {
+                pMaster = nullptr;
+                break;
+            }
+            pMaster = m_rIo.Get( nFAT, true );
+            if ( pMaster.is() )
+                nFAT = StgCache::GetFromPage( pMaster, nMasterCount );
+        }
+        if( pMaster.is() )
+            m_rIo.SetToPage( pMaster, nOff, nNewPage );
+        else
+        {
+            m_rIo.SetError( SVSTREAM_GENERALERROR );
+            bRes = false;
+        }
+    }
+
+    // lock the page against access
+    if( bRes )
+    {
+        Pos2Page( nNewPage << 2 );
+        rtl::Reference< StgPage > pPg = m_rIo.Get( m_nPage, true );
+        if( pPg.is() )
+            m_rIo.SetToPage( pPg, m_nOffset >> 2, STG_FAT );
+        else
+            bRes = false;
+    }
+    return bRes;
+}
+
+bool StgFATStrm::SetSize( sal_Int32 nBytes )
+{
+    if ( nBytes < 0 )
+        return false;
+
+    m_aPagesCache.clear();
+    m_aUsedPageNumbers.clear();
+
+    // Set the number of entries to a multiple of the page size
+    short nOld = static_cast<short>( ( m_nSize + ( m_nPageSize - 1 ) ) / m_nPageSize );
+    short nNew = static_cast<short>(
+        ( nBytes + ( m_nPageSize - 1 ) ) / m_nPageSize ) ;
+    if( nNew < nOld )
+    {
+        // release master pages
+        for( short i = nNew; i < nOld; i++ )
+            SetPage( i, STG_FREE );
+    }
+    else
+    {
+        while( nOld < nNew )
+        {
+            // allocate master pages
+            // find a free master page slot
+            sal_Int32 nPg = 0;
+            sal_uInt16 nMasterAlloc = 0;
+            nPg = GetPage( nOld, true, &nMasterAlloc );
+            if( nPg == STG_EOF )
+                return false;
+            // 4 Bytes have been used for Allocation of each MegaMasterPage
+            nBytes += nMasterAlloc << 2;
+
+            // find a free page using the FAT allocator
+            sal_Int32 n = 1;
+            OSL_ENSURE( m_pFat, "The pointer is always initializer here!" );
+            sal_Int32 nNewPage = m_pFat->FindBlock( n );
+            if( nNewPage == STG_EOF )
+            {
+                // no free pages found; create a new page
+                // Since all pages are allocated, extend
+                // the file size for the next page!
+                nNewPage = m_nSize >> 2;
+                // if a MegaMasterPage was created avoid taking
+                // the same Page
+                nNewPage += nMasterAlloc;
+                // adjust the file size if necessary
+                if( nNewPage >= m_rIo.GetPhysPages() )
+                    if( !m_rIo.SetSize( nNewPage + 1 ) )
+                        return false;
+            }
+            // Set up the page with empty entries
+            rtl::Reference< StgPage > pPg = m_rIo.Copy( nNewPage );
+            if ( !pPg.is() )
+                return false;
+            for( short j = 0; j < static_cast<short>( m_nPageSize >> 2 ); j++ )
+                m_rIo.SetToPage( pPg, j, STG_FREE );
+
+            // store the page number into the master FAT
+            // Set the size before so the correct FAT can be found
+            m_nSize = ( nOld + 1 ) * m_nPageSize;
+            SetPage( nOld, nNewPage );
+
+            // MegaMasterPages were created, mark it them as used
+
+            sal_uInt32 nMax = m_rIo.m_aHdr.GetMasters( );
+            sal_uInt32 nFAT = m_rIo.m_aHdr.GetFATChain();
+            if( nMasterAlloc )
+                for( sal_uInt32 nCount = 0; nCount < nMax; nCount++ )
+                {
+                    if( !Pos2Page( nFAT << 2 ) )
+                        return false;
+                    if( nMax - nCount <= nMasterAlloc )
+                    {
+                        rtl::Reference< StgPage > piPg = m_rIo.Get( m_nPage, true );
+                        if( !piPg.is() )
+                            return false;
+                        m_rIo.SetToPage( piPg, m_nOffset >> 2, STG_MASTER );
+                    }
+                    rtl::Reference< StgPage > pPage = m_rIo.Get( nFAT, true );
+                    if( !pPage.is() ) return false;
+                    nFAT = StgCache::GetFromPage( pPage, (m_nPageSize >> 2 ) - 1 );
+                }
+
+            nOld++;
+            // We have used up 4 bytes for the STG_FAT entry
+            nBytes += 4;
+            nNew = static_cast<short>(
+                ( nBytes + ( m_nPageSize - 1 ) ) / m_nPageSize );
+        }
+    }
+    m_nSize = nNew * m_nPageSize;
+    m_rIo.m_aHdr.SetFATSize( nNew );
+    return true;
+}
+
+/////////////////////////// class StgDataStrm
+
+// This class is a normal physical stream which can be initialized
+// either with an existing dir entry or an existing FAT chain.
+// The stream has a size increment which normally is 1, but which can be
+// set to any value is you want the size to be incremented by certain values.
+
+StgDataStrm::StgDataStrm( StgIo& r, sal_Int32 nBgn, sal_Int32 nLen ) : StgStrm( r )
+{
+    Init( nBgn, nLen );
+}
+
+StgDataStrm::StgDataStrm( StgIo& r, StgDirEntry& p ) : StgStrm( r )
+{
+    m_pEntry = &p;
+    Init( p.m_aEntry.GetLeaf( STG_DATA ),
+          p.m_aEntry.GetSize() );
+}
+
+void StgDataStrm::Init( sal_Int32 nBgn, sal_Int32 nLen )
+{
+    if ( m_rIo.m_pFAT )
+        m_pFat.reset( new StgFAT( *m_rIo.m_pFAT, true ) );
+
+    OSL_ENSURE( m_pFat, "The pointer should not be empty!" );
+
+    m_nStart = m_nPage = nBgn;
+    m_nSize  = nLen;
+    m_nIncr  = 1;
+    m_nOffset = 0;
+    if( nLen < 0 && m_pFat )
+    {
+        // determine the actual size of the stream by scanning
+        // the FAT chain and counting the # of pages allocated
+        m_nSize = scanBuildPageChainCache();
+    }
+}
+
+// Set the size of a physical stream.
+
+bool StgDataStrm::SetSize( sal_Int32 nBytes )
+{
+    if ( !m_pFat )
+        return false;
+
+    nBytes = ( ( nBytes + m_nIncr - 1 ) / m_nIncr ) * m_nIncr;
+    sal_Int32 nOldSz = m_nSize;
+    if( nOldSz != nBytes )
+    {
+        if( !StgStrm::SetSize( nBytes ) )
+            return false;
+        sal_Int32 nMaxPage = m_pFat->GetMaxPage();
+        if( nMaxPage > m_rIo.GetPhysPages() )
+            if( !m_rIo.SetSize( nMaxPage ) )
+                return false;
+        // If we only allocated one page or less, create this
+        // page in the cache for faster throughput. The current
+        // position is the former EOF point.
+        if( ( m_nSize - 1 )  / m_nPageSize - ( nOldSz - 1 ) / m_nPageSize == 1 )
+        {
+            Pos2Page( nBytes );
+            if( m_nPage >= 0 )
+                m_rIo.Copy( m_nPage );
+        }
+    }
+    return true;
+}
+
+// Get the address of the data byte at a specified offset.
+// If bForce = true, a read of non-existent data causes
+// a read fault.
+
+void* StgDataStrm::GetPtr( sal_Int32 Pos, bool bDirty )
+{
+    if( Pos2Page( Pos ) )
+    {
+        rtl::Reference< StgPage > pPg = m_rIo.Get( m_nPage, true/*bForce*/ );
+        if (pPg.is() && m_nOffset < pPg->GetSize())
+        {
+            if( bDirty )
+                m_rIo.SetDirty( pPg );
+            return static_cast<sal_uInt8 *>(pPg->GetData()) + m_nOffset;
+        }
+    }
+    return nullptr;
+}
+
+// This could easily be adapted to a better algorithm by determining
+// the amount of consecutable blocks before doing a read. The result
+// is the number of bytes read. No error is generated on EOF.
+
+sal_Int32 StgDataStrm::Read( void* pBuf, sal_Int32 n )
+{
+    if ( n < 0 )
+        return 0;
+
+    const auto nAvailable = m_nSize - GetPos();
+    if (n > nAvailable)
+        n = nAvailable;
+    sal_Int32 nDone = 0;
+    while( n )
+    {
+        short nBytes = m_nPageSize - m_nOffset;
+        rtl::Reference< StgPage > pPg;
+        if( static_cast<sal_Int32>(nBytes) > n )
+            nBytes = static_cast<short>(n);
+        if( nBytes )
+        {
+            short nRes;
+            void *p = static_cast<sal_uInt8 *>(pBuf) + nDone;
+            if( nBytes == m_nPageSize )
+            {
+                pPg = m_rIo.Find( m_nPage );
+                if( pPg.is() )
+                {
+                    // data is present, so use the cached data
+                    memcpy( p, pPg->GetData(), nBytes );
+                    nRes = nBytes;
+                }
+                else
+                    // do a direct (unbuffered) read
+                    nRes = static_cast<short>(m_rIo.Read( m_nPage, p )) * m_nPageSize;
+            }
+            else
+            {
+                // partial block read through the cache.
+                pPg = m_rIo.Get( m_nPage, false );
+                if( !pPg.is() )
+                    break;
+                memcpy( p, static_cast<sal_uInt8*>(pPg->GetData()) + m_nOffset, nBytes );
+                nRes = nBytes;
+            }
+            nDone += nRes;
+            SetPos(GetPos() + nRes, true);
+            n -= nRes;
+            m_nOffset = m_nOffset + nRes;
+            if( nRes != nBytes )
+                break;  // read error or EOF
+        }
+        // Switch to next page if necessary
+        if (m_nOffset >= m_nPageSize && !Pos2Page(GetPos()))
+            break;
+    }
+    return nDone;
+}
+
+sal_Int32 StgDataStrm::Write( const void* pBuf, sal_Int32 n )
+{
+    if ( n < 0 )
+        return 0;
+
+    sal_Int32 nDone = 0;
+    if( ( GetPos() + n ) > m_nSize )
+    {
+        sal_Int32 nOld = GetPos();
+        if( !SetSize( nOld + n ) )
+            return 0;
+        Pos2Page( nOld );
+    }
+    while( n )
+    {
+        short nBytes = m_nPageSize - m_nOffset;
+        rtl::Reference< StgPage > pPg;
+        if( static_cast<sal_Int32>(nBytes) > n )
+            nBytes = static_cast<short>(n);
+        if( nBytes )
+        {
+            short nRes;
+            const void *p = static_cast<const sal_uInt8 *>(pBuf) + nDone;
+            if( nBytes == m_nPageSize )
+            {
+                pPg = m_rIo.Find( m_nPage );
+                if( pPg.is() )
+                {
+                    // data is present, so use the cached data
+                    memcpy( pPg->GetData(), p, nBytes );
+                    m_rIo.SetDirty( pPg );
+                    nRes = nBytes;
+                }
+                else
+                    // do a direct (unbuffered) write
+                    nRes = static_cast<short>(m_rIo.Write( m_nPage, p )) * m_nPageSize;
+            }
+            else
+            {
+                // partial block read through the cache.
+                pPg = m_rIo.Get( m_nPage, false );
+                if( !pPg.is() )
+                    break;
+                memcpy( static_cast<sal_uInt8*>(pPg->GetData()) + m_nOffset, p, nBytes );
+                m_rIo.SetDirty( pPg );
+                nRes = nBytes;
+            }
+            nDone += nRes;
+            SetPos(GetPos() + nRes, true);
+            n -= nRes;
+            m_nOffset = m_nOffset + nRes;
+            if( nRes != nBytes )
+                break;  // read error
+        }
+        // Switch to next page if necessary
+        if( m_nOffset >= m_nPageSize && !Pos2Page(GetPos()) )
+            break;
+    }
+    return nDone;
+}
+
+//////////////////////////// class StgSmallStream
+
+// The small stream class provides access to streams with a size < 4096 bytes.
+// This stream is a StgStream containing small pages. The FAT for this stream
+// is also a StgStream. The start of the FAT is in the header at DataRootPage,
+// the stream itself is pointed to by the root entry (it holds start & size).
+
+StgSmallStrm::StgSmallStrm( StgIo& r, sal_Int32 nBgn ) : StgStrm( r )
+{
+    Init( nBgn, 0 );
+}
+
+StgSmallStrm::StgSmallStrm( StgIo& r, StgDirEntry& p ) : StgStrm( r )
+{
+    m_pEntry = &p;
+    Init( p.m_aEntry.GetLeaf( STG_DATA ),
+          p.m_aEntry.GetSize() );
+}
+
+void StgSmallStrm::Init( sal_Int32 nBgn, sal_Int32 nLen )
+{
+    if ( m_rIo.m_pDataFAT )
+        m_pFat.reset( new StgFAT( *m_rIo.m_pDataFAT, false ) );
+    m_pData = m_rIo.m_pDataStrm;
+    OSL_ENSURE( m_pFat && m_pData, "The pointers should not be empty!" );
+
+    m_nPageSize = m_rIo.GetDataPageSize();
+    m_nStart =
+    m_nPage  = nBgn;
+    m_nSize  = nLen;
+}
+
+// This could easily be adapted to a better algorithm by determining
+// the amount of consecutable blocks before doing a read. The result
+// is the number of bytes read. No error is generated on EOF.
+
+sal_Int32 StgSmallStrm::Read( void* pBuf, sal_Int32 n )
+{
+    // We can safely assume that reads are not huge, since the
+    // small stream is likely to be < 64 KBytes.
+    sal_Int32 nBytePos = GetPos();
+    if( ( nBytePos + n ) > m_nSize )
+        n = m_nSize - nBytePos;
+    sal_Int32 nDone = 0;
+    while( n )
+    {
+        short nBytes = m_nPageSize - m_nOffset;
+        if( static_cast<sal_Int32>(nBytes) > n )
+            nBytes = static_cast<short>(n);
+        if( nBytes )
+        {
+            if (!m_pData)
+                break;
+            sal_Int32 nPos;
+            if (o3tl::checked_multiply<sal_Int32>(m_nPage, m_nPageSize, nPos))
+                break;
+            if (!m_pData->Pos2Page(nPos + m_nOffset))
+                break;
+            // all reading through the stream
+            short nRes = static_cast<short>(m_pData->Read( static_cast<sal_uInt8*>(pBuf) + nDone, nBytes ));
+            nDone += nRes;
+            SetPos(GetPos() + nRes, true);
+            n -= nRes;
+            m_nOffset = m_nOffset + nRes;
+            // read problem?
+            if( nRes != nBytes )
+                break;
+        }
+        // Switch to next page if necessary
+        if (m_nOffset >= m_nPageSize && !Pos2Page(GetPos()))
+            break;
+    }
+    return nDone;
+}
+
+sal_Int32 StgSmallStrm::Write( const void* pBuf, sal_Int32 n )
+{
+    // you can safely assume that reads are not huge, since the
+    // small stream is likely to be < 64 KBytes.
+    sal_Int32 nDone = 0;
+    sal_Int32 nOldPos = GetPos();
+    if( ( nOldPos + n ) > m_nSize )
+    {
+        if (!SetSize(nOldPos + n))
+            return 0;
+        Pos2Page(nOldPos);
+    }
+    while( n )
+    {
+        short nBytes = m_nPageSize - m_nOffset;
+        if( static_cast<sal_Int32>(nBytes) > n )
+            nBytes = static_cast<short>(n);
+        if( nBytes )
+        {
+            // all writing goes through the stream
+            sal_Int32 nDataPos = m_nPage * m_nPageSize + m_nOffset;
+            if ( !m_pData
+              || ( m_pData->GetSize() < ( nDataPos + nBytes )
+                && !m_pData->SetSize( nDataPos + nBytes ) ) )
+                break;
+            if( !m_pData->Pos2Page( nDataPos ) )
+                break;
+            short nRes = static_cast<short>(m_pData->Write( static_cast<sal_uInt8 const *>(pBuf) + nDone, nBytes ));
+            nDone += nRes;
+            SetPos(GetPos() + nRes, true);
+            n -= nRes;
+            m_nOffset = m_nOffset + nRes;
+            // write problem?
+            if( nRes != nBytes )
+                break;
+        }
+        // Switch to next page if necessary
+        if( m_nOffset >= m_nPageSize && !Pos2Page(GetPos()) )
+            break;
+    }
+    return nDone;
+}
+
+/////////////////////////// class StgTmpStrm
+
+// The temporary stream uses a memory stream if < 32K, otherwise a
+// temporary file.
+
+#define THRESHOLD 32768L
+
+StgTmpStrm::StgTmpStrm( sal_uInt64 nInitSize )
+          : SvMemoryStream( nInitSize > THRESHOLD
+                              ? 16
+                            : ( nInitSize ? nInitSize : 16 ), 4096 )
+{
+    m_pStrm = nullptr;
+    // this calls FlushData, so all members should be set by this time
+    SetBufferSize( 0 );
+    if( nInitSize > THRESHOLD )
+        SetSize( nInitSize );
+}
+
+bool StgTmpStrm::Copy( StgTmpStrm& rSrc )
+{
+    sal_uInt64 n = rSrc.GetSize();
+    const sal_uInt64 nCur = rSrc.Tell();
+    SetSize( n );
+    if( GetError() == ERRCODE_NONE )
+    {
+        std::unique_ptr<sal_uInt8[]> p(new sal_uInt8[ 4096 ]);
+        rSrc.Seek( 0 );
+        Seek( 0 );
+        while( n )
+        {
+            const sal_uInt64 nn = std::min<sal_uInt64>(n, 4096);
+            if (rSrc.ReadBytes( p.get(), nn ) != nn)
+                break;
+            if (WriteBytes( p.get(), nn ) != nn)
+                break;
+            n -= nn;
+        }
+        p.reset();
+        rSrc.Seek( nCur );
+        Seek( nCur );
+        return n == 0;
+    }
+    else
+        return false;
+}
+
+StgTmpStrm::~StgTmpStrm()
+{
+    if( m_pStrm )
+    {
+        m_pStrm->Close();
+        osl::File::remove( m_aName );
+        delete m_pStrm;
+    }
+}
+
+sal_uInt64 StgTmpStrm::GetSize() const
+{
+    sal_uInt64 n;
+    if( m_pStrm )
+    {
+        n = m_pStrm->TellEnd();
+    }
+    else
+        n = nEndOfData;
+    return n;
+}
+
+void StgTmpStrm::SetSize(sal_uInt64 n)
+{
+    if( m_pStrm )
+        m_pStrm->SetStreamSize( n );
+    else
+    {
+        if( n > THRESHOLD )
+        {
+            m_aName = utl::TempFile(nullptr, false).GetURL();
+            std::unique_ptr<SvFileStream> s(new SvFileStream( m_aName, StreamMode::READWRITE ));
+            const sal_uInt64 nCur = Tell();
+            sal_uInt64 i = nEndOfData;
+            std::unique_ptr<sal_uInt8[]> p(new sal_uInt8[ 4096 ]);
+            if( i )
+            {
+                Seek( 0 );
+                while( i )
+                {
+                    const sal_uInt64 nb = std::min<sal_uInt64>(i, 4096);
+                    if (ReadBytes(p.get(), nb) == nb
+                        && s->WriteBytes(p.get(), nb) == nb)
+                        i -= nb;
+                    else
+                        break;
+                }
+            }
+            if( !i && n > nEndOfData )
+            {
+                // We have to write one byte at the end of the file
+                // if the file is bigger than the memstream to see
+                // if it fits on disk
+                s->Seek(nEndOfData);
+                memset(p.get(), 0x00, 4096);
+                i = n - nEndOfData;
+                while (i)
+                {
+                    const sal_uInt64 nb = std::min<sal_uInt64>(i, 4096);
+                    if (s->WriteBytes(p.get(), nb) == nb)
+                        i -= nb;
+                    else
+                        break; // error
+                }
+                s->Flush();
+                if( s->GetError() != ERRCODE_NONE )
+                    i = 1;
+            }
+            Seek( nCur );
+            s->Seek( nCur );
+            if( i )
+            {
+                SetError( s->GetError() );
+                return;
+            }
+            m_pStrm = s.release();
+            // Shrink the memory to 16 bytes, which seems to be the minimum
+            ReAllocateMemory( - ( static_cast<tools::Long>(nEndOfData) - 16 ) );
+        }
+        else
+        {
+            if( n > nEndOfData )
+            {
+                SvMemoryStream::SetSize(n);
+            }
+            else
+                nEndOfData = n;
+        }
+    }
+}
+
+std::size_t StgTmpStrm::GetData( void* pData, std::size_t n )
+{
+    if( m_pStrm )
+    {
+        n = m_pStrm->ReadBytes( pData, n );
+        SetError( m_pStrm->GetError() );
+        return n;
+    }
+    else
+        return SvMemoryStream::GetData( pData, n );
+}
+
+std::size_t StgTmpStrm::PutData( const void* pData, std::size_t n )
+{
+    sal_uInt32 nCur = Tell();
+    sal_uInt32 nNew = nCur + n;
+    if( nNew > THRESHOLD && !m_pStrm )
+    {
+        SetSize( nNew );
+        if( GetError() != ERRCODE_NONE )
+            return 0;
+    }
+    if( m_pStrm )
+    {
+        nNew = m_pStrm->WriteBytes( pData, n );
+        SetError( m_pStrm->GetError() );
+    }
+    else
+        nNew = SvMemoryStream::PutData( pData, n );
+    return nNew;
+}
+
+sal_uInt64 StgTmpStrm::SeekPos(sal_uInt64 n)
+{
+    // check if a truncated STREAM_SEEK_TO_END was passed
+    assert(n != SAL_MAX_UINT32);
+    if( n == STREAM_SEEK_TO_END )
+        n = GetSize();
+    if( n > THRESHOLD && !m_pStrm )
+    {
+        SetSize( n );
+        if( GetError() != ERRCODE_NONE )
+            return Tell();
+        else
+            return n;
+    }
+    else if( m_pStrm )
+    {
+        n = m_pStrm->Seek( n );
+        SetError( m_pStrm->GetError() );
+        return n;
+    }
+    else
+        return SvMemoryStream::SeekPos( n );
+}
+
+void StgTmpStrm::FlushData()
+{
+    if( m_pStrm )
+    {
+        m_pStrm->Flush();
+        SetError( m_pStrm->GetError() );
+    }
+    else
+        SvMemoryStream::FlushData();
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/sot/source/sdstor/stgstrms.hxx b/sot/source/sdstor/stgstrms.hxx
new file mode 100644
index 000000000..51c08faf5
--- /dev/null
+++ b/sot/source/sdstor/stgstrms.hxx
@@ -0,0 +1,168 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+#ifndef INCLUDED_SOT_SOURCE_SDSTOR_STGSTRMS_HXX
+#define INCLUDED_SOT_SOURCE_SDSTOR_STGSTRMS_HXX
+
+#include <tools/stream.hxx>
+#include <o3tl/sorted_vector.hxx>
+#include <rtl/ref.hxx>
+#include <vector>
+#include <memory>
+
+class StgIo;
+class StgStrm;
+class StgPage;
+class StgDirEntry;
+
+// The FAT class performs FAT operations on an underlying storage stream.
+// This stream is either the physical FAT stream (bPhys == true ) or a normal
+// storage stream, which then holds the FAT for small data allocations.
+
+class StgFAT
+{                                       // FAT allocator
+    StgStrm& m_rStrm;                     // underlying stream
+    sal_Int32 m_nMaxPage;                     // highest page allocated so far
+    short m_nPageSize;                    // physical page size
+    short m_nEntries;                     // FAT entries per page
+    short m_nOffset;                      // current offset within page
+    sal_Int32 m_nLimit;                       // search limit recommendation
+    bool  m_bPhys;                        // true: physical FAT
+    rtl::Reference< StgPage > GetPhysPage( sal_Int32 nPage );
+    bool  MakeChain( sal_Int32 nStart, sal_Int32 nPages );
+    bool  InitNew( sal_Int32 nPage1 );
+public:
+    StgFAT( StgStrm& rStrm, bool bMark );
+    sal_Int32 FindBlock( sal_Int32& nPages );
+    sal_Int32 GetNextPage( sal_Int32 nPg );
+    sal_Int32 AllocPages( sal_Int32 nStart, sal_Int32 nPages );
+    bool  FreePages( sal_Int32 nStart, bool bAll );
+    sal_Int32 GetMaxPage() const { return m_nMaxPage; }
+    void  SetLimit( sal_Int32 n ) { m_nLimit = n; }
+};
+
+// The base stream class provides basic functionality for seeking
+// and accessing the data on a physical basis. It uses the built-in
+// FAT class for the page allocations.
+
+class StgStrm {                           // base class for all streams
+private:
+    sal_Int32 m_nPos;                     // current byte position
+    bool m_bBytePosValid;                 // what Pos2Page returns for m_nPos
+protected:
+    StgIo& m_rIo;                         // I/O system
+    std::unique_ptr<StgFAT> m_pFat;       // FAT stream for allocations
+    StgDirEntry* m_pEntry;                // dir entry (for ownership)
+    sal_Int32 m_nStart;                       // 1st data page
+    sal_Int32 m_nSize;                        // stream size in bytes
+    sal_Int32 m_nPage;                        // current logical page
+    short m_nOffset;                      // offset into current page
+    short m_nPageSize;                    // logical page size
+    std::vector<sal_Int32> m_aPagesCache;
+    o3tl::sorted_vector<sal_Int32> m_aUsedPageNumbers;
+    sal_Int32 scanBuildPageChainCache();
+    bool  Copy( sal_Int32 nFrom, sal_Int32 nBytes );
+    void SetPos(sal_Int32 nPos, bool bValid) { m_nPos = nPos; m_bBytePosValid = bValid; }
+    explicit StgStrm( StgIo& );
+public:
+    virtual ~StgStrm();
+    StgIo&  GetIo()     { return m_rIo;    }
+    sal_Int32   GetPos() const   { return m_nPos; }
+    sal_Int32   GetStart() const { return m_nStart; }
+    sal_Int32   GetSize() const  { return m_nSize;  }
+    sal_Int32   GetPage() const  { return m_nPage;  }
+    sal_Int32   GetPages() const { return ( m_nSize + m_nPageSize - 1 ) / m_nPageSize;}
+    short       GetOffset() const { return m_nOffset;}
+    void        SetEntry( StgDirEntry& );
+    virtual bool SetSize( sal_Int32 );
+    virtual bool Pos2Page( sal_Int32 nBytePos );
+    virtual sal_Int32 Read( void*, sal_Int32 )        { return 0; }
+    virtual sal_Int32 Write( const void*, sal_Int32 ) { return 0; }
+    virtual bool IsSmallStrm() const { return false; }
+};
+
+// The FAT stream class provides physical access to the master FAT.
+// Since this access is implemented as a StgStrm, we can use the
+// FAT allocator.
+
+class StgFATStrm : public StgStrm {     // the master FAT stream
+    virtual bool Pos2Page( sal_Int32 nBytePos ) override;
+    bool  SetPage( short, sal_Int32 );
+public:
+    explicit StgFATStrm(StgIo&, sal_Int32 nFatStrmSize);
+    using StgStrm::GetPage;
+    sal_Int32 GetPage(sal_Int32, bool, sal_uInt16 *pnMasterAlloc = nullptr);
+    virtual bool SetSize( sal_Int32 ) override;
+};
+
+// The stream has a size increment which normally is 1, but which can be
+// set to any value is you want the size to be incremented by certain values.
+
+class StgDataStrm : public StgStrm      // a physical data stream
+{
+    short m_nIncr;                        // size adjust increment
+    void Init( sal_Int32 nBgn, sal_Int32 nLen );
+public:
+    StgDataStrm( StgIo&, sal_Int32 nBgn, sal_Int32 nLen=-1 );
+    StgDataStrm( StgIo&, StgDirEntry& );
+    void* GetPtr( sal_Int32 nPos, bool bDirty );
+    void SetIncrement( short n ) { m_nIncr = n ; }
+    virtual bool SetSize( sal_Int32 ) override;
+    virtual sal_Int32 Read( void*, sal_Int32 ) override;
+    virtual sal_Int32 Write( const void*, sal_Int32 ) override;
+};
+
+// The small stream class provides access to streams with a size < 4096 bytes.
+// This stream is a StgStream containing small pages. The FAT for this stream
+// is also a StgStream. The start of the FAT is in the header at DataRootPage,
+// the stream itself is pointed to by the root entry (it holds start & size).
+
+class StgSmallStrm : public StgStrm     // a logical data stream
+{
+    StgStrm* m_pData;                     // the data stream
+    void Init( sal_Int32 nBgn, sal_Int32 nLen );
+public:
+    StgSmallStrm( StgIo&, sal_Int32 nBgn );
+    StgSmallStrm( StgIo&, StgDirEntry& );
+    virtual sal_Int32 Read( void*, sal_Int32 ) override;
+    virtual sal_Int32 Write( const void*, sal_Int32 ) override;
+    virtual bool IsSmallStrm() const override { return true; }
+};
+
+class StgTmpStrm : public SvMemoryStream
+{
+    OUString m_aName;
+    SvFileStream* m_pStrm;
+    using SvMemoryStream::GetData;
+    virtual std::size_t GetData( void* pData, std::size_t nSize ) override;
+    virtual std::size_t PutData( const void* pData, std::size_t nSize ) override;
+    virtual sal_uInt64 SeekPos( sal_uInt64 nPos ) override;
+    virtual void FlushData() override;
+
+public:
+    explicit StgTmpStrm( sal_uInt64=16 );
+    virtual ~StgTmpStrm() override;
+    bool Copy( StgTmpStrm& );
+    virtual void SetSize( sal_uInt64 ) override;
+    sal_uInt64 GetSize() const;
+};
+
+#endif
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/sot/source/sdstor/storage.cxx b/sot/source/sdstor/storage.cxx
new file mode 100644
index 000000000..f1ff0455c
--- /dev/null
+++ b/sot/source/sdstor/storage.cxx
@@ -0,0 +1,803 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+#include <sal/config.h>
+#include <sal/log.hxx>
+
+#include <com/sun/star/embed/XStorage.hpp>
+#include <com/sun/star/embed/ElementModes.hpp>
+#include <com/sun/star/beans/XPropertySet.hpp>
+
+#include <osl/file.hxx>
+#include <sot/stg.hxx>
+#include <sot/storinfo.hxx>
+#include <sot/storage.hxx>
+#include <sot/formats.hxx>
+#include <sot/exchange.hxx>
+#include <unotools/ucbstreamhelper.hxx>
+#include <tools/diagnose_ex.h>
+#include <tools/debug.hxx>
+#include <tools/urlobj.hxx>
+#include <unotools/ucbhelper.hxx>
+#include <comphelper/fileformat.h>
+#include <com/sun/star/uno/Reference.h>
+
+#include <memory>
+
+using namespace ::com::sun::star;
+
+static SvLockBytesRef MakeLockBytes_Impl( const OUString & rName, StreamMode nMode )
+{
+    SvLockBytesRef xLB;
+    if( !rName.isEmpty() )
+    {
+        SvStream * pFileStm = new SvFileStream( rName, nMode );
+        xLB = new SvLockBytes( pFileStm, true );
+    }
+    else
+    {
+        SvStream * pCacheStm = new SvMemoryStream();
+        xLB = new SvLockBytes( pCacheStm, true );
+    }
+    return xLB;
+}
+
+SotTempStream::SotTempStream( const OUString & rName, StreamMode nMode )
+    : SvStream( MakeLockBytes_Impl( rName, nMode ).get() )
+{
+    if( nMode & StreamMode::WRITE )
+        m_isWritable = true;
+    else
+        m_isWritable = false;
+}
+
+SotTempStream::~SotTempStream()
+{
+    FlushBuffer();
+}
+
+void SotTempStream::CopyTo( SotTempStream * pDestStm )
+{
+    FlushBuffer(); // write all data
+
+    sal_uInt64 nPos = Tell();    // save position
+    Seek( 0 );
+    pDestStm->SetSize( 0 ); // empty target stream
+
+    constexpr int BUFSIZE = 64 * 1024;
+    std::unique_ptr<sal_uInt8[]> pMem(new sal_uInt8[ BUFSIZE ]);
+    sal_Int32  nRead;
+    while (0 != (nRead = ReadBytes(pMem.get(), BUFSIZE)))
+    {
+        if (nRead != static_cast<sal_Int32>(pDestStm->WriteBytes(pMem.get(), nRead)))
+        {
+            SetError( SVSTREAM_GENERALERROR );
+            break;
+        }
+    }
+    pMem.reset();
+
+    // set position
+    pDestStm->Seek( nPos );
+    Seek( nPos );
+}
+
+SotStorageStream::SotStorageStream( BaseStorageStream * pStm )
+    : pOwnStm(pStm)
+{
+    assert( pStm );
+    if( StreamMode::WRITE & pStm->GetMode() )
+        m_isWritable = true;
+    else
+        m_isWritable = false;
+
+    SetError( pStm->GetError() );
+    pStm->ResetError();
+}
+
+SotStorageStream::~SotStorageStream()
+{
+    Flush();
+    delete pOwnStm;
+}
+
+void SotStorageStream::ResetError()
+{
+    SvStream::ResetError();
+    pOwnStm->ResetError();
+}
+
+std::size_t SotStorageStream::GetData(void* pData, std::size_t const nSize)
+{
+    std::size_t nRet = pOwnStm->Read( pData, nSize );
+    SetError( pOwnStm->GetError() );
+    return nRet;
+}
+
+std::size_t SotStorageStream::PutData(const void* pData, std::size_t const nSize)
+{
+    std::size_t nRet = pOwnStm->Write( pData, nSize );
+    SetError( pOwnStm->GetError() );
+    return nRet;
+}
+
+sal_uInt64 SotStorageStream::SeekPos(sal_uInt64 nPos)
+{
+    sal_uInt64 nRet = pOwnStm->Seek( nPos );
+    SetError( pOwnStm->GetError() );
+    return nRet;
+}
+
+void SotStorageStream::FlushData()
+{
+    pOwnStm->Flush();
+    SetError( pOwnStm->GetError() );
+}
+
+void SotStorageStream::SetSize(sal_uInt64 const nNewSize)
+{
+    sal_uInt64 const nPos = Tell();
+    pOwnStm->SetSize( nNewSize );
+    SetError( pOwnStm->GetError() );
+
+    if( nNewSize < nPos )
+        // jump to the end
+        Seek( nNewSize );
+}
+
+sal_uInt32 SotStorageStream::GetSize() const
+{
+    sal_uInt64 nSize = const_cast<SotStorageStream*>(this)->TellEnd();
+    return nSize;
+}
+
+sal_uInt64 SotStorageStream::TellEnd()
+{
+    // Need to flush the buffer so we materialise the stream and return the correct answer
+    // otherwise we return a 0 value from StgEntry::GetSize
+    FlushBuffer();
+
+    return pOwnStm->GetSize();
+}
+
+void SotStorageStream::Commit()
+{
+    pOwnStm->Flush();
+    if( pOwnStm->GetError() == ERRCODE_NONE )
+        pOwnStm->Commit();
+    SetError( pOwnStm->GetError() );
+}
+
+bool SotStorageStream::SetProperty( const OUString& rName, const css::uno::Any& rValue )
+{
+    UCBStorageStream* pStg =  dynamic_cast<UCBStorageStream*>( pOwnStm );
+    if ( pStg )
+    {
+        return pStg->SetProperty( rName, rValue );
+    }
+    else
+    {
+        OSL_FAIL("Not implemented!");
+        return false;
+    }
+}
+
+/**
+ * SotStorage::SotStorage()
+ *
+ * A I... object must be passed to SvObject, because otherwise itself will
+ * create and define an IUnknown, so that all other I... objects would be
+ * destroyed with delete (Owner() == true).
+ * But IStorage objects are only used and not implemented by ourselves,
+ * therefore we pretend the IStorage object was passed from the outside
+ * and it will be freed with Release().
+ * The CreateStorage methods are needed to create an IStorage object before the
+ * call of SvObject (Own, !Own automatic).
+ * If CreateStorage has created an object, then the RefCounter was already
+ * incremented.
+ * The transfer is done in pStorageCTor and the variable is NULL, if it didn't
+ * work.
+ */
+#define INIT_SotStorage()                     \
+    : m_pOwnStg( nullptr )                       \
+    , m_pStorStm( nullptr )                      \
+    , m_nError( ERRCODE_NONE )                 \
+    , m_bIsRoot( false )                      \
+    , m_bDelStm( false )                      \
+    , m_nVersion( SOFFICE_FILEFORMAT_CURRENT )
+
+#define ERASEMASK  ( StreamMode::TRUNC | StreamMode::WRITE | StreamMode::SHARE_DENYALL )
+
+SotStorage::SotStorage( const OUString & rName, StreamMode nMode )
+    INIT_SotStorage()
+{
+    m_aName = rName; // save name
+    CreateStorage( true, nMode );
+    if ( IsOLEStorage() )
+        m_nVersion = SOFFICE_FILEFORMAT_50;
+}
+
+void SotStorage::CreateStorage( bool bForceUCBStorage, StreamMode nMode )
+{
+    DBG_ASSERT( !m_pStorStm && !m_pOwnStg, "Use only in ctor!" );
+    if( !m_aName.isEmpty() )
+    {
+        // named storage
+        if( ( nMode & ERASEMASK ) == ERASEMASK )
+            ::utl::UCBContentHelper::Kill( m_aName );
+
+        INetURLObject aObj( m_aName );
+        if ( aObj.GetProtocol() == INetProtocol::NotValid )
+        {
+            OUString aURL;
+            osl::FileBase::getFileURLFromSystemPath( m_aName, aURL );
+            aObj.SetURL( aURL );
+            m_aName = aObj.GetMainURL( INetURLObject::DecodeMechanism::NONE );
+        }
+
+        // check the stream
+        m_pStorStm = ::utl::UcbStreamHelper::CreateStream( m_aName, nMode ).release();
+        if ( m_pStorStm && m_pStorStm->GetError() )
+        {
+            delete m_pStorStm;
+            m_pStorStm = nullptr;
+        }
+
+        if ( m_pStorStm )
+        {
+            // try as UCBStorage, next try as OLEStorage
+            bool bIsUCBStorage = UCBStorage::IsStorageFile( m_pStorStm );
+            if ( !bIsUCBStorage && bForceUCBStorage )
+                // if UCBStorage has priority, it should not be used only if it is really an OLEStorage
+                bIsUCBStorage = !Storage::IsStorageFile( m_pStorStm );
+
+            if ( bIsUCBStorage )
+            {
+                // UCBStorage always works directly on the UCB content, so discard the stream first
+                delete m_pStorStm;
+                m_pStorStm = nullptr;
+                m_pOwnStg = new UCBStorage( m_aName, nMode, true, true/*bIsRoot*/ );
+            }
+            else
+            {
+                // OLEStorage can be opened with a stream
+                m_pOwnStg = new Storage( *m_pStorStm, true );
+                m_bDelStm = true;
+            }
+        }
+        else if ( bForceUCBStorage )
+        {
+            m_pOwnStg = new UCBStorage( m_aName, nMode, true, true/*bIsRoot*/ );
+            SetError( ERRCODE_IO_NOTSUPPORTED );
+        }
+        else
+        {
+            m_pOwnStg = new Storage( m_aName, nMode, true );
+            SetError( ERRCODE_IO_NOTSUPPORTED );
+        }
+    }
+    else
+    {
+        // temporary storage
+        if ( bForceUCBStorage )
+            m_pOwnStg = new UCBStorage( m_aName, nMode, true, true/*bIsRoot*/ );
+        else
+            m_pOwnStg = new Storage( m_aName, nMode, true );
+        m_aName = m_pOwnStg->GetName();
+    }
+
+    SetError( m_pOwnStg->GetError() );
+
+    SignAsRoot( m_pOwnStg->IsRoot() );
+}
+
+SotStorage::SotStorage( bool bUCBStorage, const OUString & rName, StreamMode nMode )
+    INIT_SotStorage()
+{
+    m_aName = rName;
+    CreateStorage( bUCBStorage, nMode );
+    if ( IsOLEStorage() )
+        m_nVersion = SOFFICE_FILEFORMAT_50;
+}
+
+SotStorage::SotStorage( BaseStorage * pStor )
+    INIT_SotStorage()
+{
+    if ( pStor )
+    {
+        m_aName = pStor->GetName(); // save name
+        SignAsRoot( pStor->IsRoot() );
+        SetError( pStor->GetError() );
+    }
+
+    m_pOwnStg = pStor;
+    const ErrCode nErr = m_pOwnStg ? m_pOwnStg->GetError() : SVSTREAM_CANNOT_MAKE;
+    SetError( nErr );
+    if ( IsOLEStorage() )
+        m_nVersion = SOFFICE_FILEFORMAT_50;
+}
+
+SotStorage::SotStorage( bool bUCBStorage, SvStream & rStm )
+    INIT_SotStorage()
+{
+    SetError( rStm.GetError() );
+
+    // try as UCBStorage, next try as OLEStorage
+    if ( UCBStorage::IsStorageFile( &rStm ) || bUCBStorage )
+        m_pOwnStg = new UCBStorage( rStm, false );
+    else
+        m_pOwnStg = new Storage( rStm, false );
+
+    SetError( m_pOwnStg->GetError() );
+
+    if ( IsOLEStorage() )
+        m_nVersion = SOFFICE_FILEFORMAT_50;
+
+    SignAsRoot( m_pOwnStg->IsRoot() );
+}
+
+SotStorage::SotStorage( SvStream & rStm )
+    INIT_SotStorage()
+{
+    SetError( rStm.GetError() );
+
+    // try as UCBStorage, next try as OLEStorage
+    if ( UCBStorage::IsStorageFile( &rStm ) )
+        m_pOwnStg = new UCBStorage( rStm, false );
+    else
+        m_pOwnStg = new Storage( rStm, false );
+
+    SetError( m_pOwnStg->GetError() );
+
+    if ( IsOLEStorage() )
+        m_nVersion = SOFFICE_FILEFORMAT_50;
+
+    SignAsRoot( m_pOwnStg->IsRoot() );
+}
+
+SotStorage::SotStorage( SvStream * pStm, bool bDelete )
+    INIT_SotStorage()
+{
+    SetError( pStm->GetError() );
+
+    // try as UCBStorage, next try as OLEStorage
+    if ( UCBStorage::IsStorageFile( pStm ) )
+        m_pOwnStg = new UCBStorage( *pStm, false );
+    else
+        m_pOwnStg = new Storage( *pStm, false );
+
+    SetError( m_pOwnStg->GetError() );
+
+    m_pStorStm = pStm;
+    m_bDelStm = bDelete;
+    if ( IsOLEStorage() )
+        m_nVersion = SOFFICE_FILEFORMAT_50;
+
+    SignAsRoot( m_pOwnStg->IsRoot() );
+}
+
+SotStorage::~SotStorage()
+{
+    delete m_pOwnStg;
+    if( m_bDelStm )
+        delete m_pStorStm;
+}
+
+std::unique_ptr<SvMemoryStream> SotStorage::CreateMemoryStream()
+{
+    std::unique_ptr<SvMemoryStream> pStm(new SvMemoryStream( 0x8000, 0x8000 ));
+    tools::SvRef<SotStorage> aStg = new SotStorage( *pStm );
+    if( CopyTo( aStg.get() ) )
+    {
+        aStg->Commit();
+    }
+    else
+    {
+        aStg.clear(); // release storage beforehand
+        pStm.reset();
+    }
+    return pStm;
+}
+
+bool SotStorage::IsStorageFile( const OUString & rFileName )
+{
+    OUString aName( rFileName );
+    INetURLObject aObj( aName );
+    if ( aObj.GetProtocol() == INetProtocol::NotValid )
+    {
+        OUString aURL;
+        osl::FileBase::getFileURLFromSystemPath( aName, aURL );
+        aObj.SetURL( aURL );
+        aName = aObj.GetMainURL( INetURLObject::DecodeMechanism::NONE );
+    }
+
+    std::unique_ptr<SvStream> pStm(::utl::UcbStreamHelper::CreateStream( aName, StreamMode::STD_READ ));
+    bool bRet = SotStorage::IsStorageFile( pStm.get() );
+    return bRet;
+}
+
+bool SotStorage::IsStorageFile( SvStream* pStream )
+{
+    /** code for new storages must come first! **/
+    if ( pStream )
+    {
+        sal_uInt64 nPos = pStream->Tell();
+        bool bRet = UCBStorage::IsStorageFile( pStream );
+        if ( !bRet )
+            bRet = Storage::IsStorageFile( pStream );
+        pStream->Seek( nPos );
+        return bRet;
+    }
+    else
+        return false;
+}
+
+const OUString & SotStorage::GetName() const
+{
+    if( m_aName.isEmpty() && m_pOwnStg )
+        const_cast<SotStorage *>(this)->m_aName = m_pOwnStg->GetName();
+    return m_aName;
+}
+
+void SotStorage::SetClass( const SvGlobalName & rName,
+                           SotClipboardFormatId nOriginalClipFormat,
+                           const OUString & rUserTypeName )
+{
+    if( m_pOwnStg )
+        m_pOwnStg->SetClass( rName, nOriginalClipFormat, rUserTypeName );
+    else
+        SetError( SVSTREAM_GENERALERROR );
+}
+
+SvGlobalName SotStorage::GetClassName()
+{
+    SvGlobalName aGN;
+    if( m_pOwnStg )
+        aGN = m_pOwnStg->GetClassName();
+    else
+        SetError( SVSTREAM_GENERALERROR );
+    return aGN;
+}
+
+SotClipboardFormatId SotStorage::GetFormat()
+{
+    SotClipboardFormatId nFormat = SotClipboardFormatId::NONE;
+    if( m_pOwnStg )
+        nFormat = m_pOwnStg->GetFormat();
+    else
+        SetError( SVSTREAM_GENERALERROR );
+    return nFormat;
+}
+
+OUString SotStorage::GetUserName()
+{
+    OUString aName;
+    if( m_pOwnStg )
+        aName = m_pOwnStg->GetUserName();
+    else
+        SetError( SVSTREAM_GENERALERROR );
+    return aName;
+}
+
+void SotStorage::FillInfoList( SvStorageInfoList * pFillList ) const
+{
+    if( m_pOwnStg )
+        m_pOwnStg->FillInfoList( pFillList );
+}
+
+bool SotStorage::CopyTo( SotStorage * pDestStg )
+{
+    if( m_pOwnStg && pDestStg->m_pOwnStg )
+    {
+        m_pOwnStg->CopyTo( pDestStg->m_pOwnStg );
+        SetError( m_pOwnStg->GetError() );
+        pDestStg->m_aKey = m_aKey;
+        pDestStg->m_nVersion = m_nVersion;
+    }
+    else
+        SetError( SVSTREAM_GENERALERROR );
+
+    return ERRCODE_NONE == GetError();
+}
+
+bool SotStorage::Commit()
+{
+    if( m_pOwnStg )
+    {
+        if( !m_pOwnStg->Commit() )
+            SetError( m_pOwnStg->GetError() );
+    }
+    else
+        SetError( SVSTREAM_GENERALERROR );
+
+    return ERRCODE_NONE == GetError();
+}
+
+tools::SvRef<SotStorageStream> SotStorage::OpenSotStream( const OUString & rEleName,
+                                              StreamMode nMode )
+{
+    tools::SvRef<SotStorageStream> pStm;
+    if( m_pOwnStg )
+    {
+        // enable full Ole patches,
+        // regardless what is coming, only exclusively allowed
+        nMode |= StreamMode::SHARE_DENYALL;
+        ErrCode nE = m_pOwnStg->GetError();
+        BaseStorageStream * p = m_pOwnStg->OpenStream( rEleName, nMode );
+        pStm = new SotStorageStream( p );
+
+        if( !nE )
+            m_pOwnStg->ResetError(); // don't set error
+        if( nMode & StreamMode::TRUNC )
+            pStm->SetSize( 0 );
+    }
+    else
+        SetError( SVSTREAM_GENERALERROR );
+
+    return pStm;
+}
+
+SotStorage * SotStorage::OpenSotStorage( const OUString & rEleName,
+                                         StreamMode nMode,
+                                         bool transacted )
+{
+    if( m_pOwnStg )
+    {
+        nMode |= StreamMode::SHARE_DENYALL;
+        ErrCode nE = m_pOwnStg->GetError();
+        BaseStorage * p = m_pOwnStg->OpenStorage(rEleName, nMode, !transacted);
+        if( p )
+        {
+            SotStorage * pStor = new SotStorage( p );
+            if( !nE )
+                m_pOwnStg->ResetError(); // don't set error
+
+            return pStor;
+        }
+    }
+
+    SetError( SVSTREAM_GENERALERROR );
+
+    return nullptr;
+}
+
+bool SotStorage::IsStorage( const OUString & rEleName ) const
+{
+    // a little bit faster
+    if( m_pOwnStg )
+        return m_pOwnStg->IsStorage( rEleName );
+
+    return false;
+}
+
+bool SotStorage::IsStream( const OUString & rEleName ) const
+{
+    // a little bit faster
+    if( m_pOwnStg )
+        return m_pOwnStg->IsStream( rEleName );
+
+    return false;
+}
+
+bool SotStorage::IsContained( const OUString & rEleName ) const
+{
+    // a little bit faster
+    if( m_pOwnStg )
+        return m_pOwnStg->IsContained( rEleName );
+
+    return false;
+}
+
+bool SotStorage::Remove( const OUString & rEleName )
+{
+    if( m_pOwnStg )
+    {
+        m_pOwnStg->Remove( rEleName );
+        SetError( m_pOwnStg->GetError() );
+    }
+    else
+        SetError( SVSTREAM_GENERALERROR );
+
+    return ERRCODE_NONE == GetError();
+}
+
+bool SotStorage::CopyTo( const OUString & rEleName,
+                         SotStorage * pNewSt, const OUString & rNewName )
+{
+    if( m_pOwnStg )
+    {
+        m_pOwnStg->CopyTo( rEleName, pNewSt->m_pOwnStg, rNewName );
+        SetError( m_pOwnStg->GetError() );
+        SetError( pNewSt->GetError() );
+    }
+    else
+        SetError( SVSTREAM_GENERALERROR );
+
+    return ERRCODE_NONE == GetError();
+}
+
+bool SotStorage::Validate()
+{
+    DBG_ASSERT( m_bIsRoot, "Validate only if root storage" );
+    if( m_pOwnStg )
+        return m_pOwnStg->ValidateFAT();
+    else
+        return true;
+}
+
+bool SotStorage::IsOLEStorage() const
+{
+    UCBStorage* pStg =  dynamic_cast<UCBStorage*>( m_pOwnStg );
+    return !pStg;
+}
+
+bool SotStorage::IsOLEStorage( const OUString & rFileName )
+{
+    return Storage::IsStorageFile( rFileName );
+}
+
+bool SotStorage::IsOLEStorage( SvStream* pStream )
+{
+    return Storage::IsStorageFile( pStream );
+}
+
+SotStorage* SotStorage::OpenOLEStorage( const css::uno::Reference < css::embed::XStorage >& xStorage,
+                                        const OUString& rEleName, StreamMode nMode )
+{
+    sal_Int32 nEleMode = embed::ElementModes::SEEKABLEREAD;
+    if ( nMode & StreamMode::WRITE )
+        nEleMode |= embed::ElementModes::WRITE;
+    if ( nMode & StreamMode::TRUNC )
+        nEleMode |= embed::ElementModes::TRUNCATE;
+    if ( nMode & StreamMode::NOCREATE )
+        nEleMode |= embed::ElementModes::NOCREATE;
+
+    std::unique_ptr<SvStream> pStream;
+    try
+    {
+        uno::Reference < io::XStream > xStream = xStorage->openStreamElement( rEleName, nEleMode );
+
+        // TODO/LATER: should it be done this way?
+        if ( nMode & StreamMode::WRITE )
+        {
+            uno::Reference < beans::XPropertySet > xStreamProps( xStream, uno::UNO_QUERY_THROW );
+            xStreamProps->setPropertyValue( "MediaType",
+                                            uno::Any( OUString(  "application/vnd.sun.star.oleobject"  ) ) );
+        }
+
+        pStream = utl::UcbStreamHelper::CreateStream( xStream );
+    }
+    catch ( uno::Exception& )
+    {
+        //TODO/LATER: ErrorHandling
+        pStream.reset( new SvMemoryStream );
+        pStream->SetError( ERRCODE_IO_GENERAL );
+    }
+
+    return new SotStorage( pStream.release(), true );
+}
+
+SotClipboardFormatId SotStorage::GetFormatID( const css::uno::Reference < css::embed::XStorage >& xStorage )
+{
+    uno::Reference< beans::XPropertySet > xProps( xStorage, uno::UNO_QUERY );
+    if ( !xProps.is() )
+        return SotClipboardFormatId::NONE;
+
+    OUString aMediaType;
+    try
+    {
+        xProps->getPropertyValue("MediaType") >>= aMediaType;
+    }
+    catch (uno::Exception const&)
+    {
+        TOOLS_INFO_EXCEPTION("sot", "SotStorage::GetFormatID");
+    }
+
+    if ( !aMediaType.isEmpty() )
+    {
+        css::datatransfer::DataFlavor aDataFlavor;
+        aDataFlavor.MimeType = aMediaType;
+        return SotExchange::GetFormat( aDataFlavor );
+    }
+
+    return SotClipboardFormatId::NONE;
+}
+
+sal_Int32 SotStorage::GetVersion( const css::uno::Reference < css::embed::XStorage >& xStorage )
+{
+    SotClipboardFormatId nSotFormatID = SotStorage::GetFormatID( xStorage );
+    switch( nSotFormatID )
+    {
+    case SotClipboardFormatId::STARWRITER_8:
+    case SotClipboardFormatId::STARWRITER_8_TEMPLATE:
+    case SotClipboardFormatId::STARWRITERWEB_8:
+    case SotClipboardFormatId::STARWRITERGLOB_8:
+    case SotClipboardFormatId::STARWRITERGLOB_8_TEMPLATE:
+    case SotClipboardFormatId::STARDRAW_8:
+    case SotClipboardFormatId::STARDRAW_8_TEMPLATE:
+    case SotClipboardFormatId::STARIMPRESS_8:
+    case SotClipboardFormatId::STARIMPRESS_8_TEMPLATE:
+    case SotClipboardFormatId::STARCALC_8:
+    case SotClipboardFormatId::STARCALC_8_TEMPLATE:
+    case SotClipboardFormatId::STARCHART_8:
+    case SotClipboardFormatId::STARCHART_8_TEMPLATE:
+    case SotClipboardFormatId::STARMATH_8:
+    case SotClipboardFormatId::STARMATH_8_TEMPLATE:
+        return SOFFICE_FILEFORMAT_8;
+    case SotClipboardFormatId::STARWRITER_60:
+    case SotClipboardFormatId::STARWRITERWEB_60:
+    case SotClipboardFormatId::STARWRITERGLOB_60:
+    case SotClipboardFormatId::STARDRAW_60:
+    case SotClipboardFormatId::STARIMPRESS_60:
+    case SotClipboardFormatId::STARCALC_60:
+    case SotClipboardFormatId::STARCHART_60:
+    case SotClipboardFormatId::STARMATH_60:
+        return SOFFICE_FILEFORMAT_60;
+    default: break;
+    }
+
+    return 0;
+}
+
+namespace
+{
+    void traverse(const tools::SvRef<SotStorage>& rStorage, std::vector<unsigned char>& rBuf)
+    {
+        SvStorageInfoList infos;
+
+        rStorage->FillInfoList(&infos);
+
+        for (const auto& info: infos)
+        {
+            if (info.IsStream())
+            {
+                // try to open and read all content
+                tools::SvRef<SotStorageStream> xStream(rStorage->OpenSotStream(info.GetName(), StreamMode::STD_READ));
+                const size_t nSize = xStream->GetSize();
+                const size_t nRead = xStream->ReadBytes(rBuf.data(), nSize);
+                SAL_INFO("sot", "Read " << nRead << "bytes");
+            }
+            else if (info.IsStorage())
+            {
+                tools::SvRef<SotStorage> xStorage(rStorage->OpenSotStorage(info.GetName(), StreamMode::STD_READ));
+
+                // continue with children
+                traverse(xStorage, rBuf);
+            }
+        }
+    }
+}
+
+extern "C" SAL_DLLPUBLIC_EXPORT bool TestImportOLE2(SvStream &rStream)
+{
+    try
+    {
+        size_t nSize = rStream.remainingSize();
+        tools::SvRef<SotStorage> xRootStorage(new SotStorage(&rStream, false));
+        std::vector<unsigned char> aTmpBuf(nSize);
+        traverse(xRootStorage, aTmpBuf);
+    }
+    catch (...)
+    {
+        return false;
+    }
+    return true;
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/sot/source/sdstor/storinfo.cxx b/sot/source/sdstor/storinfo.cxx
new file mode 100644
index 000000000..d8480e86a
--- /dev/null
+++ b/sot/source/sdstor/storinfo.cxx
@@ -0,0 +1,98 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+
+#include <sot/storinfo.hxx>
+#include <sot/exchange.hxx>
+#include <tools/stream.hxx>
+#include <vcl/errcode.hxx>
+#include <memory>
+
+/************** class SvStorageInfo **************************************
+*************************************************************************/
+SotClipboardFormatId ReadClipboardFormat( SvStream & rStm )
+{
+    SotClipboardFormatId nFormat = SotClipboardFormatId::NONE;
+    sal_Int32 nLen = 0;
+    rStm.ReadInt32( nLen );
+    if( rStm.eof() )
+        rStm.SetError( SVSTREAM_GENERALERROR );
+    if( nLen > 0 )
+    {
+        // get a string name
+        std::unique_ptr<char[]> p(new( ::std::nothrow ) char[ nLen ]);
+        if (p && rStm.ReadBytes(p.get(), nLen) == static_cast<std::size_t>(nLen))
+        {
+            nFormat = SotExchange::RegisterFormatName(OUString(p.get(), nLen-1, RTL_TEXTENCODING_ASCII_US));
+        }
+        else
+            rStm.SetError( SVSTREAM_GENERALERROR );
+    }
+    else if( nLen == -1 )
+    {
+        // Windows clipboard format
+        // SV and Win match (up to and including SotClipboardFormatId::GDIMETAFILE)
+        sal_uInt32 nTmp;
+        rStm.ReadUInt32( nTmp );
+        nFormat = static_cast<SotClipboardFormatId>(nTmp);
+    }
+    else if( nLen == -2 )
+    {
+        sal_uInt32 nTmp;
+        rStm.ReadUInt32( nTmp );
+        nFormat = static_cast<SotClipboardFormatId>(nTmp);
+        // Mac clipboard format
+        // ??? not implemented
+        rStm.SetError( SVSTREAM_GENERALERROR );
+    }
+    else if( nLen != 0 )
+    {
+        // unknown identifier
+        rStm.SetError( SVSTREAM_GENERALERROR );
+    }
+    return nFormat;
+}
+
+void WriteClipboardFormat( SvStream & rStm, SotClipboardFormatId nFormat )
+{
+    // determine the clipboard format string
+    OUString aCbFmt;
+    if( nFormat > SotClipboardFormatId::GDIMETAFILE )
+        aCbFmt = SotExchange::GetFormatName( nFormat );
+    if( !aCbFmt.isEmpty() )
+    {
+        OString aAsciiCbFmt(OUStringToOString(aCbFmt,
+                                              RTL_TEXTENCODING_ASCII_US));
+        rStm.WriteInt32( aAsciiCbFmt.getLength() + 1 );
+        rStm.WriteOString( aAsciiCbFmt );
+        rStm.WriteUChar( 0 );
+    }
+    else if( nFormat != SotClipboardFormatId::NONE )
+    {
+        rStm.WriteInt32( -1 )         // for Windows
+            .WriteInt32( static_cast<sal_Int32>(nFormat) );
+    }
+    else
+    {
+        rStm.WriteInt32( 0 );         // no clipboard format
+    }
+}
+
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/sot/source/sdstor/ucbstorage.cxx b/sot/source/sdstor/ucbstorage.cxx
new file mode 100644
index 000000000..4e2dc1a2a
--- /dev/null
+++ b/sot/source/sdstor/ucbstorage.cxx
@@ -0,0 +1,2845 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+#include <com/sun/star/io/NotConnectedException.hpp>
+#include <com/sun/star/io/BufferSizeExceededException.hpp>
+#include <com/sun/star/uno/RuntimeException.hpp>
+#include <ucbhelper/content.hxx>
+#include <com/sun/star/uno/Reference.h>
+#include <com/sun/star/ucb/NameClash.hpp>
+#include <unotools/tempfile.hxx>
+#include <unotools/ucbstreamhelper.hxx>
+#include <com/sun/star/io/XInputStream.hpp>
+#include <com/sun/star/ucb/InsertCommandArgument.hpp>
+#include <com/sun/star/ucb/ResultSetException.hpp>
+#include <com/sun/star/uno/Sequence.h>
+#include <com/sun/star/sdbc/XResultSet.hpp>
+#include <com/sun/star/sdbc/XRow.hpp>
+#include <com/sun/star/ucb/CommandAbortedException.hpp>
+#include <com/sun/star/datatransfer/DataFlavor.hpp>
+#include <com/sun/star/ucb/ContentInfo.hpp>
+#include <com/sun/star/ucb/ContentInfoAttribute.hpp>
+#include <com/sun/star/beans/Property.hpp>
+#include <com/sun/star/packages/manifest/ManifestWriter.hpp>
+#include <com/sun/star/packages/manifest/ManifestReader.hpp>
+#include <com/sun/star/ucb/InteractiveIOException.hpp>
+#include <com/sun/star/ucb/ContentCreationException.hpp>
+
+#include <memory>
+#include <optional>
+#include <o3tl/safeint.hxx>
+#include <osl/diagnose.h>
+#include <osl/file.hxx>
+#include <sal/log.hxx>
+#include <tools/diagnose_ex.h>
+#include <tools/ref.hxx>
+#include <tools/debug.hxx>
+#include <unotools/streamwrap.hxx>
+#include <unotools/ucbhelper.hxx>
+#include <tools/urlobj.hxx>
+#include <comphelper/processfactory.hxx>
+#include <comphelper/propertyvalue.hxx>
+#include <cppuhelper/implbase.hxx>
+#include <ucbhelper/commandenvironment.hxx>
+
+#include <sot/stg.hxx>
+#include <sot/storinfo.hxx>
+#include <sot/exchange.hxx>
+#include <sot/formats.hxx>
+#include <comphelper/classids.hxx>
+
+#include <mutex>
+#include <utility>
+#include <vector>
+
+namespace com::sun::star::ucb { class XCommandEnvironment; }
+
+using namespace ::com::sun::star::lang;
+using namespace ::com::sun::star::beans;
+using namespace ::com::sun::star::uno;
+using namespace ::com::sun::star::ucb;
+using namespace ::com::sun::star::io;
+using namespace ::com::sun::star::sdbc;
+using namespace ::ucbhelper;
+
+#if OSL_DEBUG_LEVEL > 0
+static int nOpenFiles=0;
+static int nOpenStreams=0;
+#endif
+
+typedef ::cppu::WeakImplHelper < XInputStream, XSeekable > FileInputStreamWrapper_Base;
+
+namespace {
+
+class FileStreamWrapper_Impl : public FileInputStreamWrapper_Base
+{
+protected:
+    std::mutex    m_aMutex;
+    OUString        m_aURL;
+    std::unique_ptr<SvStream> m_pSvStream;
+
+public:
+    explicit FileStreamWrapper_Impl(OUString aName);
+    virtual ~FileStreamWrapper_Impl() override;
+
+    virtual void SAL_CALL seek( sal_Int64 _nLocation ) override;
+    virtual sal_Int64 SAL_CALL getPosition(  ) override;
+    virtual sal_Int64 SAL_CALL getLength(  ) override;
+    virtual sal_Int32 SAL_CALL readBytes( Sequence< sal_Int8 >& aData, sal_Int32 nBytesToRead) override;
+    virtual sal_Int32 SAL_CALL readSomeBytes( Sequence< sal_Int8 >& aData, sal_Int32 nMaxBytesToRead) override;
+    virtual void      SAL_CALL skipBytes(sal_Int32 nBytesToSkip) override;
+    virtual sal_Int32 SAL_CALL available() override;
+    virtual void      SAL_CALL closeInput() override;
+
+protected:
+    void checkConnected();
+    void checkError();
+};
+
+}
+
+FileStreamWrapper_Impl::FileStreamWrapper_Impl( OUString aName )
+    : m_aURL(std::move( aName ))
+{
+    // if no URL is provided the stream is empty
+}
+
+
+FileStreamWrapper_Impl::~FileStreamWrapper_Impl()
+{
+    if ( m_pSvStream )
+    {
+        m_pSvStream.reset();
+#if OSL_DEBUG_LEVEL > 0
+        --nOpenFiles;
+#endif
+    }
+
+    if (!m_aURL.isEmpty())
+        osl::File::remove(m_aURL);
+}
+
+
+sal_Int32 SAL_CALL FileStreamWrapper_Impl::readBytes(Sequence< sal_Int8 >& aData, sal_Int32 nBytesToRead)
+{
+    if ( m_aURL.isEmpty() )
+    {
+        aData.realloc( 0 );
+        return 0;
+    }
+
+    checkConnected();
+
+    if (nBytesToRead < 0)
+        throw BufferSizeExceededException(OUString(),static_cast<XWeak*>(this));
+
+    std::scoped_lock aGuard( m_aMutex );
+
+    if (aData.getLength() < nBytesToRead)
+        aData.realloc(nBytesToRead);
+
+    sal_uInt32 nRead = m_pSvStream->ReadBytes(static_cast<void*>(aData.getArray()), nBytesToRead);
+    checkError();
+
+    // if read characters < MaxLength, adjust sequence
+    if (nRead < o3tl::make_unsigned(aData.getLength()))
+        aData.realloc( nRead );
+
+    return nRead;
+}
+
+
+sal_Int32 SAL_CALL FileStreamWrapper_Impl::readSomeBytes(Sequence< sal_Int8 >& aData, sal_Int32 nMaxBytesToRead)
+{
+    if ( m_aURL.isEmpty() )
+    {
+        aData.realloc( 0 );
+        return 0;
+    }
+
+    checkError();
+
+    if (nMaxBytesToRead < 0)
+        throw BufferSizeExceededException(OUString(),static_cast<XWeak*>(this));
+
+    if (m_pSvStream->eof())
+    {
+        aData.realloc(0);
+        return 0;
+    }
+    else
+        return readBytes(aData, nMaxBytesToRead);
+}
+
+
+void SAL_CALL FileStreamWrapper_Impl::skipBytes(sal_Int32 nBytesToSkip)
+{
+    if ( m_aURL.isEmpty() )
+        return;
+
+    std::scoped_lock aGuard( m_aMutex );
+    checkError();
+
+    m_pSvStream->SeekRel(nBytesToSkip);
+    checkError();
+}
+
+
+sal_Int32 SAL_CALL FileStreamWrapper_Impl::available()
+{
+    if ( m_aURL.isEmpty() )
+        return 0;
+
+    std::scoped_lock aGuard( m_aMutex );
+    checkConnected();
+
+    sal_Int64 nAvailable = m_pSvStream->remainingSize();
+    checkError();
+
+    return std::min<sal_Int64>(SAL_MAX_INT32, nAvailable);
+}
+
+
+void SAL_CALL FileStreamWrapper_Impl::closeInput()
+{
+    if ( m_aURL.isEmpty() )
+        return;
+
+    std::scoped_lock aGuard( m_aMutex );
+    checkConnected();
+    m_pSvStream.reset();
+#if OSL_DEBUG_LEVEL > 0
+    --nOpenFiles;
+#endif
+    osl::File::remove(m_aURL);
+    m_aURL.clear();
+}
+
+
+void SAL_CALL FileStreamWrapper_Impl::seek( sal_Int64 _nLocation )
+{
+    if ( m_aURL.isEmpty() )
+        return;
+
+    std::scoped_lock aGuard( m_aMutex );
+    checkConnected();
+
+    m_pSvStream->Seek(static_cast<sal_uInt32>(_nLocation));
+    checkError();
+}
+
+
+sal_Int64 SAL_CALL FileStreamWrapper_Impl::getPosition(  )
+{
+    if ( m_aURL.isEmpty() )
+        return 0;
+
+    std::scoped_lock aGuard( m_aMutex );
+    checkConnected();
+
+    sal_uInt32 nPos = m_pSvStream->Tell();
+    checkError();
+    return static_cast<sal_Int64>(nPos);
+}
+
+
+sal_Int64 SAL_CALL FileStreamWrapper_Impl::getLength(  )
+{
+    if ( m_aURL.isEmpty() )
+        return 0;
+
+    std::scoped_lock aGuard( m_aMutex );
+    checkConnected();
+
+    checkError();
+
+    sal_Int64 nEndPos = m_pSvStream->TellEnd();
+
+    return nEndPos;
+}
+
+
+void FileStreamWrapper_Impl::checkConnected()
+{
+    if ( m_aURL.isEmpty() )
+        throw NotConnectedException(OUString(), static_cast<XWeak*>(this));
+    if ( !m_pSvStream )
+    {
+        m_pSvStream = ::utl::UcbStreamHelper::CreateStream( m_aURL, StreamMode::STD_READ );
+#if OSL_DEBUG_LEVEL > 0
+        ++nOpenFiles;
+#endif
+    }
+}
+
+
+void FileStreamWrapper_Impl::checkError()
+{
+    checkConnected();
+
+    if (m_pSvStream->SvStream::GetError() != ERRCODE_NONE)
+        // TODO: really evaluate the error
+        throw NotConnectedException(OUString(), static_cast<XWeak*>(this));
+}
+
+
+#define COMMIT_RESULT_FAILURE           0
+#define COMMIT_RESULT_NOTHING_TO_DO     1
+#define COMMIT_RESULT_SUCCESS           2
+
+static SotClipboardFormatId GetFormatId_Impl( const SvGlobalName& aName )
+{
+    if ( aName == SvGlobalName( SO3_SW_CLASSID_60 ) )
+        return SotClipboardFormatId::STARWRITER_60;
+    if ( aName == SvGlobalName( SO3_SWWEB_CLASSID_60 ) )
+        return SotClipboardFormatId::STARWRITERWEB_60;
+    if ( aName == SvGlobalName( SO3_SWGLOB_CLASSID_60 ) )
+        return SotClipboardFormatId::STARWRITERGLOB_60;
+    if ( aName == SvGlobalName( SO3_SDRAW_CLASSID_60 ) )
+        return SotClipboardFormatId::STARDRAW_60;
+    if ( aName == SvGlobalName( SO3_SIMPRESS_CLASSID_60 ) )
+        return SotClipboardFormatId::STARIMPRESS_60;
+    if ( aName == SvGlobalName( SO3_SC_CLASSID_60 ) )
+        return SotClipboardFormatId::STARCALC_60;
+    if ( aName == SvGlobalName( SO3_SCH_CLASSID_60 ) )
+        return SotClipboardFormatId::STARCHART_60;
+    if ( aName == SvGlobalName( SO3_SM_CLASSID_60 ) )
+        return SotClipboardFormatId::STARMATH_60;
+    if ( aName == SvGlobalName( SO3_OUT_CLASSID ) ||
+         aName == SvGlobalName( SO3_APPLET_CLASSID ) ||
+         aName == SvGlobalName( SO3_PLUGIN_CLASSID ) ||
+         aName == SvGlobalName( SO3_IFRAME_CLASSID ) )
+        // allowed, but not supported
+        return SotClipboardFormatId::NONE;
+    else
+    {
+        OSL_FAIL( "Unknown UCB storage format!" );
+        return SotClipboardFormatId::NONE;
+    }
+}
+
+
+static SvGlobalName GetClassId_Impl( SotClipboardFormatId nFormat )
+{
+    switch ( nFormat )
+    {
+        case SotClipboardFormatId::STARWRITER_8 :
+        case SotClipboardFormatId::STARWRITER_8_TEMPLATE :
+            return SvGlobalName( SO3_SW_CLASSID_60 );
+        case SotClipboardFormatId::STARWRITERWEB_8 :
+            return SvGlobalName( SO3_SWWEB_CLASSID_60 );
+        case SotClipboardFormatId::STARWRITERGLOB_8 :
+        case SotClipboardFormatId::STARWRITERGLOB_8_TEMPLATE :
+            return SvGlobalName( SO3_SWGLOB_CLASSID_60 );
+        case SotClipboardFormatId::STARDRAW_8 :
+        case SotClipboardFormatId::STARDRAW_8_TEMPLATE :
+            return SvGlobalName( SO3_SDRAW_CLASSID_60 );
+        case SotClipboardFormatId::STARIMPRESS_8 :
+        case SotClipboardFormatId::STARIMPRESS_8_TEMPLATE :
+            return SvGlobalName( SO3_SIMPRESS_CLASSID_60 );
+        case SotClipboardFormatId::STARCALC_8 :
+        case SotClipboardFormatId::STARCALC_8_TEMPLATE :
+            return SvGlobalName( SO3_SC_CLASSID_60 );
+        case SotClipboardFormatId::STARCHART_8 :
+        case SotClipboardFormatId::STARCHART_8_TEMPLATE :
+            return SvGlobalName( SO3_SCH_CLASSID_60 );
+        case SotClipboardFormatId::STARMATH_8 :
+        case SotClipboardFormatId::STARMATH_8_TEMPLATE :
+            return SvGlobalName( SO3_SM_CLASSID_60 );
+        case SotClipboardFormatId::STARWRITER_60 :
+            return SvGlobalName( SO3_SW_CLASSID_60 );
+        case SotClipboardFormatId::STARWRITERWEB_60 :
+            return SvGlobalName( SO3_SWWEB_CLASSID_60 );
+        case SotClipboardFormatId::STARWRITERGLOB_60 :
+            return SvGlobalName( SO3_SWGLOB_CLASSID_60 );
+        case SotClipboardFormatId::STARDRAW_60 :
+            return SvGlobalName( SO3_SDRAW_CLASSID_60 );
+        case SotClipboardFormatId::STARIMPRESS_60 :
+            return SvGlobalName( SO3_SIMPRESS_CLASSID_60 );
+        case SotClipboardFormatId::STARCALC_60 :
+            return SvGlobalName( SO3_SC_CLASSID_60 );
+        case SotClipboardFormatId::STARCHART_60 :
+            return SvGlobalName( SO3_SCH_CLASSID_60 );
+        case SotClipboardFormatId::STARMATH_60 :
+            return SvGlobalName( SO3_SM_CLASSID_60 );
+        default :
+            return SvGlobalName();
+    }
+}
+
+// All storage and streams are refcounted internally; outside of this classes they are only accessible through a handle
+// class, that uses the refcounted object as impl-class.
+
+class UCBStorageStream_Impl : public SvRefBase, public SvStream
+{
+                                virtual ~UCBStorageStream_Impl() override;
+public:
+
+    virtual std::size_t         GetData(void* pData, std::size_t nSize) override;
+    virtual std::size_t         PutData(const void* pData, std::size_t nSize) override;
+    virtual sal_uInt64          SeekPos( sal_uInt64 nPos ) override;
+    virtual void                SetSize( sal_uInt64 nSize ) override;
+    virtual void                FlushData() override;
+    virtual void                ResetError() override;
+
+    UCBStorageStream*           m_pAntiImpl;    // only valid if an external reference exists
+
+    OUString                    m_aOriginalName;// the original name before accessing the stream
+    OUString                    m_aName;        // the actual name ( changed with a Rename command at the parent )
+    OUString                    m_aURL;         // the full path name to create the content
+    OUString                    m_aContentType;
+    OUString                    m_aOriginalContentType;
+    OString                     m_aKey;
+    ::ucbhelper::Content*       m_pContent;     // the content that provides the data
+    Reference<XInputStream>     m_rSource;      // the stream covering the original data of the content
+    std::unique_ptr<SvStream>   m_pStream;      // the stream worked on; for readonly streams it is the original stream of the content
+                                                // for read/write streams it's a copy into a temporary file
+    OUString                    m_aTempURL;     // URL of this temporary stream
+    ErrCode                     m_nError;
+    StreamMode                  m_nMode;        // open mode ( read/write/trunc/nocreate/sharing )
+    bool                        m_bSourceRead;  // Source still contains useful information
+    bool                        m_bModified;    // only modified streams will be sent to the original content
+    bool                        m_bCommited;    // sending the streams is coordinated by the root storage of the package
+    bool                        m_bDirect;      // the storage and its streams are opened in direct mode; for UCBStorages
+                                                // this means that the root storage does an autocommit when its external
+                                                // reference is destroyed
+    bool                        m_bIsOLEStorage;// an OLEStorage on a UCBStorageStream makes this an Autocommit-stream
+
+                                UCBStorageStream_Impl( const OUString&, StreamMode, UCBStorageStream*, bool,
+                                                       bool bRepair, Reference< XProgressHandler > const & xProgress );
+
+    void                        Free();
+    bool                        Init();
+    bool                        Clear();
+    sal_Int16                   Commit();       // if modified and committed: transfer an XInputStream to the content
+    void                        Revert();       // discard all changes
+    BaseStorage*                CreateStorage();// create an OLE Storage on the UCBStorageStream
+    sal_uInt64                  GetSize();
+
+    sal_uInt64                  ReadSourceWriteTemporary( sal_uInt64 aLength ); // read aLength from source and copy to temporary,
+                                                                           // no seeking is produced
+    void                        ReadSourceWriteTemporary();                // read source till the end and copy to temporary,
+
+    void                        CopySourceToTemporary();                // same as ReadSourceWriteToTemporary()
+                                                                        // but the writing is done at the end of temporary
+                                                                        // pointer position is not changed
+    using SvStream::SetError;
+    void                        SetError( ErrCode nError );
+    void                        PrepareCachedForReopen( StreamMode nMode );
+};
+
+typedef tools::SvRef<UCBStorageStream_Impl> UCBStorageStream_ImplRef;
+
+struct UCBStorageElement_Impl;
+typedef std::vector<std::unique_ptr<UCBStorageElement_Impl>> UCBStorageElementList_Impl;
+
+class UCBStorage_Impl : public SvRefBase
+{
+                                virtual ~UCBStorage_Impl() override;
+public:
+    UCBStorage*                 m_pAntiImpl;    // only valid if external references exists
+
+    OUString                    m_aName;        // the actual name ( changed with a Rename command at the parent )
+    OUString                    m_aURL;         // the full path name to create the content
+    OUString                    m_aContentType;
+    OUString                    m_aOriginalContentType;
+    std::unique_ptr<::ucbhelper::Content> m_pContent;     // the content that provides the storage elements
+    std::unique_ptr<::utl::TempFile>      m_pTempFile;    // temporary file, only for storages on stream
+    SvStream*                   m_pSource;      // original stream, only for storages on a stream
+    ErrCode                     m_nError;
+    StreamMode                  m_nMode;        // open mode ( read/write/trunc/nocreate/sharing )
+    bool                        m_bCommited;    // sending the streams is coordinated by the root storage of the package
+    bool                        m_bDirect;      // the storage and its streams are opened in direct mode; for UCBStorages
+                                                // this means that the root storage does an autocommit when its external
+                                                // reference is destroyed
+    bool                        m_bIsRoot;      // marks this storage as root storages that manages all commits and reverts
+    bool                        m_bIsLinked;
+    bool                        m_bListCreated;
+    SotClipboardFormatId        m_nFormat;
+    OUString                    m_aUserTypeName;
+    SvGlobalName                m_aClassId;
+
+    UCBStorageElementList_Impl  m_aChildrenList;
+
+    bool                        m_bRepairPackage;
+    Reference< XProgressHandler > m_xProgressHandler;
+
+                                UCBStorage_Impl( const ::ucbhelper::Content&, const OUString&, StreamMode, UCBStorage*, bool,
+                                                 bool, bool = false, Reference< XProgressHandler > const & = Reference< XProgressHandler >() );
+                                UCBStorage_Impl( const OUString&, StreamMode, UCBStorage*, bool, bool,
+                                                 bool, Reference< XProgressHandler > const & );
+                                UCBStorage_Impl( SvStream&, UCBStorage*, bool );
+    void                        Init();
+    sal_Int16                   Commit();
+    void                        Revert();
+    bool                        Insert( ::ucbhelper::Content *pContent );
+    UCBStorage_Impl*            OpenStorage( UCBStorageElement_Impl* pElement, StreamMode nMode, bool bDirect );
+    void                        OpenStream( UCBStorageElement_Impl*, StreamMode, bool );
+    void                        SetProps( const Sequence < Sequence < PropertyValue > >& rSequence, const OUString& );
+    void                        GetProps( sal_Int32&, Sequence < Sequence < PropertyValue > >& rSequence, const OUString& );
+    sal_Int32                   GetObjectCount();
+    void                        ReadContent();
+    void                        CreateContent();
+    ::ucbhelper::Content*       GetContent()
+                                {
+                                    if ( !m_pContent )
+                                        CreateContent();
+                                    return m_pContent.get();
+                                }
+    UCBStorageElementList_Impl& GetChildrenList()
+                                {
+                                    const ErrCode nError = m_nError;
+                                    ReadContent();
+                                    if ( m_nMode & StreamMode::WRITE )
+                                    {
+                                        m_nError = nError;
+                                        if ( m_pAntiImpl )
+                                        {
+                                            m_pAntiImpl->ResetError();
+                                            m_pAntiImpl->SetError( nError );
+                                        }
+                                    }
+                                    return m_aChildrenList;
+                                }
+
+    void                        SetError( ErrCode nError );
+};
+
+typedef tools::SvRef<UCBStorage_Impl> UCBStorage_ImplRef;
+
+// this struct contains all necessary information on an element inside a UCBStorage
+struct UCBStorageElement_Impl
+{
+    OUString                    m_aName;        // the actual URL relative to the root "folder"
+    OUString                    m_aOriginalName;// the original name in the content
+    sal_uInt64                  m_nSize;
+    bool                        m_bIsFolder;    // Only true when it is a UCBStorage !
+    bool                        m_bIsStorage;   // Also true when it is an OLEStorage !
+    bool                        m_bIsRemoved;   // element will be removed on commit
+    bool                        m_bIsInserted;  // element will be removed on revert
+    UCBStorage_ImplRef          m_xStorage;     // reference to the "real" storage
+    UCBStorageStream_ImplRef    m_xStream;      // reference to the "real" stream
+
+                                UCBStorageElement_Impl( const OUString& rName,
+                                                        bool bIsFolder = false, sal_uInt64 nSize = 0 )
+                                    : m_aName( rName )
+                                    , m_aOriginalName( rName )
+                                    , m_nSize( nSize )
+                                    , m_bIsFolder( bIsFolder )
+                                    , m_bIsStorage( bIsFolder )
+                                    , m_bIsRemoved( false )
+                                    , m_bIsInserted( false )
+                                {
+                                }
+
+    ::ucbhelper::Content*       GetContent();
+    bool                        IsModified() const;
+    OUString                    GetContentType() const;
+    void                        SetContentType( const OUString& );
+    OUString                    GetOriginalContentType() const;
+    bool                        IsLoaded() const
+                                { return m_xStream.is() || m_xStorage.is(); }
+};
+
+::ucbhelper::Content* UCBStorageElement_Impl::GetContent()
+{
+    if ( m_xStream.is() )
+        return m_xStream->m_pContent;
+    else if ( m_xStorage.is() )
+        return m_xStorage->GetContent();
+    else
+        return nullptr;
+}
+
+OUString UCBStorageElement_Impl::GetContentType() const
+{
+    if ( m_xStream.is() )
+        return m_xStream->m_aContentType;
+    else if ( m_xStorage.is() )
+        return m_xStorage->m_aContentType;
+    else
+    {
+        OSL_FAIL("Element not loaded!");
+        return OUString();
+    }
+}
+
+void UCBStorageElement_Impl::SetContentType( const OUString& rType )
+{
+    if ( m_xStream.is() ) {
+        m_xStream->m_aContentType = m_xStream->m_aOriginalContentType = rType;
+    }
+    else if ( m_xStorage.is() ) {
+        m_xStorage->m_aContentType = m_xStorage->m_aOriginalContentType = rType;
+    }
+    else {
+        OSL_FAIL("Element not loaded!");
+    }
+}
+
+OUString UCBStorageElement_Impl::GetOriginalContentType() const
+{
+    if ( m_xStream.is() )
+        return m_xStream->m_aOriginalContentType;
+    else if ( m_xStorage.is() )
+        return m_xStorage->m_aOriginalContentType;
+    else
+        return OUString();
+}
+
+bool UCBStorageElement_Impl::IsModified() const
+{
+    bool bModified = m_bIsRemoved || m_bIsInserted || m_aName != m_aOriginalName;
+    if ( bModified )
+    {
+        if ( m_xStream.is() )
+            bModified = m_xStream->m_aContentType != m_xStream->m_aOriginalContentType;
+        else if ( m_xStorage.is() )
+            bModified = m_xStorage->m_aContentType != m_xStorage->m_aOriginalContentType;
+    }
+
+    return bModified;
+}
+
+UCBStorageStream_Impl::UCBStorageStream_Impl( const OUString& rName, StreamMode nMode, UCBStorageStream* pStream, bool bDirect, bool bRepair, Reference< XProgressHandler > const & xProgress  )
+    : m_pAntiImpl( pStream )
+    , m_aURL( rName )
+    , m_pContent( nullptr )
+    , m_nError( ERRCODE_NONE )
+    , m_nMode( nMode )
+    , m_bSourceRead( !( nMode & StreamMode::TRUNC ) )
+    , m_bModified( false )
+    , m_bCommited( false )
+    , m_bDirect( bDirect )
+    , m_bIsOLEStorage( false )
+{
+    // name is last segment in URL
+    INetURLObject aObj( rName );
+    m_aName = m_aOriginalName = aObj.GetLastName();
+    try
+    {
+        // create the content
+        Reference< css::ucb::XCommandEnvironment > xComEnv;
+
+        OUString aTemp( rName );
+
+        if ( bRepair )
+        {
+            xComEnv = new ::ucbhelper::CommandEnvironment( Reference< css::task::XInteractionHandler >(), xProgress );
+            aTemp += "?repairpackage";
+        }
+
+        m_pContent = new ::ucbhelper::Content( aTemp, xComEnv, comphelper::getProcessComponentContext() );
+    }
+    catch (const ContentCreationException&)
+    {
+        // content could not be created
+        SetError( SVSTREAM_CANNOT_MAKE );
+    }
+    catch (const RuntimeException&)
+    {
+        // any other error - not specified
+        SetError( ERRCODE_IO_GENERAL );
+    }
+}
+
+UCBStorageStream_Impl::~UCBStorageStream_Impl()
+{
+    if( m_rSource.is() )
+        m_rSource.clear();
+
+    m_pStream.reset();
+
+    if (!m_aTempURL.isEmpty())
+        osl::File::remove(m_aTempURL);
+
+    delete m_pContent;
+}
+
+
+bool UCBStorageStream_Impl::Init()
+{
+    if( !m_pStream )
+    {
+        // no temporary stream was created
+        // create one
+
+        if ( m_aTempURL.isEmpty() )
+            m_aTempURL = ::utl::TempFile().GetURL();
+
+        m_pStream = ::utl::UcbStreamHelper::CreateStream( m_aTempURL, StreamMode::STD_READWRITE, true /* bFileExists */ );
+#if OSL_DEBUG_LEVEL > 0
+        ++nOpenFiles;
+#endif
+
+        if( !m_pStream )
+        {
+            OSL_FAIL( "Suspicious temporary stream creation!" );
+            SetError( SVSTREAM_CANNOT_MAKE );
+            return false;
+        }
+
+        SetError( m_pStream->GetError() );
+    }
+
+    if( m_bSourceRead && !m_rSource.is() )
+    {
+        // source file contain useful information and is not opened
+        // open it from the point of noncopied data
+
+        try
+        {
+            m_rSource = m_pContent->openStream();
+        }
+        catch (const Exception&)
+        {
+            // usually means that stream could not be opened
+        }
+
+        if( m_rSource.is() )
+        {
+            m_pStream->Seek( STREAM_SEEK_TO_END );
+
+            try
+            {
+                m_rSource->skipBytes( m_pStream->Tell() );
+            }
+            catch (const BufferSizeExceededException&)
+            {
+                // the temporary stream already contain all the data
+                m_bSourceRead = false;
+            }
+            catch (const Exception&)
+            {
+                // something is really wrong
+                m_bSourceRead = false;
+                OSL_FAIL( "Can not operate original stream!" );
+                SetError( SVSTREAM_CANNOT_MAKE );
+            }
+
+            m_pStream->Seek( 0 );
+        }
+        else
+        {
+            // if the new file is edited then no source exist
+            m_bSourceRead = false;
+                //SetError( SVSTREAM_CANNOT_MAKE );
+        }
+    }
+
+    DBG_ASSERT( m_rSource.is() || !m_bSourceRead, "Unreadable source stream!" );
+
+    return true;
+}
+
+void UCBStorageStream_Impl::ReadSourceWriteTemporary()
+{
+    // read source stream till the end and copy all the data to
+    // the current position of the temporary stream
+
+    if( m_bSourceRead )
+    {
+        Sequence<sal_Int8> aData(32000);
+
+        try
+        {
+            sal_Int32 aReaded;
+            do
+            {
+                aReaded = m_rSource->readBytes( aData, 32000 );
+                m_pStream->WriteBytes(aData.getConstArray(), aReaded);
+            } while( aReaded == 32000 );
+        }
+        catch (const Exception &)
+        {
+            TOOLS_WARN_EXCEPTION("sot", "");
+        }
+    }
+
+    m_bSourceRead = false;
+}
+
+sal_uInt64 UCBStorageStream_Impl::ReadSourceWriteTemporary(sal_uInt64 aLength)
+{
+    // read aLength bite from the source stream and copy them to the current
+    // position of the temporary stream
+
+    sal_uInt64 aResult = 0;
+
+    if( m_bSourceRead )
+    {
+        Sequence<sal_Int8> aData(32000);
+
+        try
+        {
+
+            sal_Int32 aReaded = 32000;
+
+            for (sal_uInt64 nInd = 0; nInd < aLength && aReaded == 32000 ; nInd += 32000)
+            {
+                sal_Int32 aToCopy = std::min<sal_Int32>( aLength - nInd, 32000 );
+                aReaded = m_rSource->readBytes( aData, aToCopy );
+                aResult += m_pStream->WriteBytes(aData.getConstArray(), aReaded);
+            }
+
+            if( aResult < aLength )
+                m_bSourceRead = false;
+        }
+        catch( const Exception & )
+        {
+            TOOLS_WARN_EXCEPTION("sot", "");
+        }
+    }
+
+    return aResult;
+}
+
+void UCBStorageStream_Impl::CopySourceToTemporary()
+{
+    // current position of the temporary stream is not changed
+    if( m_bSourceRead )
+    {
+        sal_uInt64 aPos = m_pStream->Tell();
+        m_pStream->Seek( STREAM_SEEK_TO_END );
+        ReadSourceWriteTemporary();
+        m_pStream->Seek( aPos );
+    }
+}
+
+// UCBStorageStream_Impl must have a SvStream interface, because it then can be used as underlying stream
+// of an OLEStorage; so every write access caused by storage operations marks the UCBStorageStream as modified
+std::size_t UCBStorageStream_Impl::GetData(void* pData, std::size_t const nSize)
+{
+    std::size_t aResult = 0;
+
+    if( !Init() )
+        return 0;
+
+
+    // read data that is in temporary stream
+    aResult = m_pStream->ReadBytes( pData, nSize );
+    if( m_bSourceRead && aResult < nSize )
+    {
+        // read the tail of the data from original stream
+        // copy this tail to the temporary stream
+
+        std::size_t aToRead = nSize - aResult;
+        pData = static_cast<void*>( static_cast<char*>(pData) + aResult );
+
+        try
+        {
+            Sequence<sal_Int8> aData( aToRead );
+            std::size_t aReaded = m_rSource->readBytes( aData, aToRead );
+            aResult += m_pStream->WriteBytes(static_cast<const void*>(aData.getConstArray()), aReaded);
+            memcpy( pData, aData.getArray(), aReaded );
+        }
+        catch (const Exception &)
+        {
+            TOOLS_WARN_EXCEPTION("sot", "");
+        }
+
+        if( aResult < nSize )
+            m_bSourceRead = false;
+    }
+
+    return aResult;
+}
+
+std::size_t UCBStorageStream_Impl::PutData(const void* pData, std::size_t const nSize)
+{
+    if ( !(m_nMode & StreamMode::WRITE) )
+    {
+        SetError( ERRCODE_IO_ACCESSDENIED );
+        return 0; // ?mav?
+    }
+
+    if( !nSize || !Init() )
+        return 0;
+
+    std::size_t aResult = m_pStream->WriteBytes( pData, nSize );
+
+    m_bModified = aResult > 0;
+
+    return aResult;
+
+}
+
+sal_uInt64 UCBStorageStream_Impl::SeekPos(sal_uInt64 const nPos)
+{
+    // check if a truncated STREAM_SEEK_TO_END was passed
+    assert(nPos != SAL_MAX_UINT32);
+
+    if( !Init() )
+        return 0;
+
+    sal_uInt64 aResult;
+
+    if( nPos == STREAM_SEEK_TO_END )
+    {
+        m_pStream->Seek( STREAM_SEEK_TO_END );
+        ReadSourceWriteTemporary();
+        aResult = m_pStream->Tell();
+    }
+    else
+    {
+        // the problem is that even if nPos is larger the length
+        // of the stream, the stream pointer will be moved to this position
+        // so we have to check if temporary stream does not contain required position
+
+        if( m_pStream->Tell() > nPos
+            || m_pStream->Seek( STREAM_SEEK_TO_END ) > nPos )
+        {
+            // no copying is required
+            aResult = m_pStream->Seek( nPos );
+        }
+        else
+        {
+            // the temp stream pointer points to the end now
+            aResult = m_pStream->Tell();
+
+            if( aResult < nPos )
+            {
+                if( m_bSourceRead )
+                {
+                    aResult += ReadSourceWriteTemporary( nPos - aResult );
+                    if( aResult < nPos )
+                        m_bSourceRead = false;
+
+                    DBG_ASSERT( aResult == m_pStream->Tell(), "Error in stream arithmetic!\n" );
+                }
+
+                if( (m_nMode & StreamMode::WRITE) && !m_bSourceRead && aResult < nPos )
+                {
+                    // it means that all the Source stream was copied already
+                    // but the required position still was not reached
+                    // for writable streams it should be done
+                    m_pStream->SetStreamSize( nPos );
+                    aResult = m_pStream->Seek( STREAM_SEEK_TO_END );
+                    DBG_ASSERT( aResult == nPos, "Error in stream arithmetic!\n" );
+                }
+            }
+        }
+    }
+
+    return aResult;
+}
+
+void  UCBStorageStream_Impl::SetSize(sal_uInt64 const nSize)
+{
+    if ( !(m_nMode & StreamMode::WRITE) )
+    {
+        SetError( ERRCODE_IO_ACCESSDENIED );
+        return;
+    }
+
+    if( !Init() )
+        return;
+
+    m_bModified = true;
+
+    if( m_bSourceRead )
+    {
+        sal_uInt64 const aPos = m_pStream->Tell();
+        m_pStream->Seek( STREAM_SEEK_TO_END );
+        if( m_pStream->Tell() < nSize )
+            ReadSourceWriteTemporary( nSize - m_pStream->Tell() );
+        m_pStream->Seek( aPos );
+    }
+
+    m_pStream->SetStreamSize( nSize );
+    m_bSourceRead = false;
+}
+
+void  UCBStorageStream_Impl::FlushData()
+{
+    if( m_pStream )
+    {
+        CopySourceToTemporary();
+        m_pStream->Flush();
+    }
+
+    m_bCommited = true;
+}
+
+void UCBStorageStream_Impl::SetError( ErrCode nErr )
+{
+    if ( !m_nError )
+    {
+        m_nError = nErr;
+        SvStream::SetError( nErr );
+        if ( m_pAntiImpl ) m_pAntiImpl->SetError( nErr );
+    }
+}
+
+void  UCBStorageStream_Impl::ResetError()
+{
+    m_nError = ERRCODE_NONE;
+    SvStream::ResetError();
+    if ( m_pAntiImpl )
+        m_pAntiImpl->ResetError();
+}
+
+sal_uInt64 UCBStorageStream_Impl::GetSize()
+{
+    if( !Init() )
+        return 0;
+
+    sal_uInt64 nPos = m_pStream->Tell();
+    m_pStream->Seek( STREAM_SEEK_TO_END );
+    ReadSourceWriteTemporary();
+    sal_uInt64 nRet = m_pStream->Tell();
+    m_pStream->Seek( nPos );
+
+    return nRet;
+}
+
+BaseStorage* UCBStorageStream_Impl::CreateStorage()
+{
+    // create an OLEStorage on a SvStream ( = this )
+    // it gets the root attribute because otherwise it would probably not write before my root is committed
+    UCBStorageStream* pNewStorageStream = new UCBStorageStream( this );
+    Storage *pStorage = new Storage( *pNewStorageStream, m_bDirect );
+
+    // GetError() call clears error code for OLE storages, must be changed in future
+    const ErrCode nTmpErr = pStorage->GetError();
+    pStorage->SetError( nTmpErr );
+
+    m_bIsOLEStorage = !nTmpErr;
+    return static_cast< BaseStorage* > ( pStorage );
+}
+
+sal_Int16 UCBStorageStream_Impl::Commit()
+{
+    // send stream to the original content
+    // the  parent storage is responsible for the correct handling of deleted contents
+    if ( m_bCommited || m_bIsOLEStorage || m_bDirect )
+    {
+        // modified streams with OLEStorages on it have autocommit; it is assumed that the OLEStorage
+        // was committed as well ( if not opened in direct mode )
+
+        if ( m_bModified )
+        {
+            try
+            {
+                CopySourceToTemporary();
+
+                // release all stream handles
+                Free();
+
+                // the temporary file does not exist only for truncated streams
+                DBG_ASSERT( !m_aTempURL.isEmpty() || ( m_nMode & StreamMode::TRUNC ), "No temporary file to read from!");
+                if ( m_aTempURL.isEmpty() && !( m_nMode & StreamMode::TRUNC ) )
+                    throw RuntimeException();
+
+                // create wrapper to stream that is only used while reading inside package component
+                Reference < XInputStream > xStream = new FileStreamWrapper_Impl( m_aTempURL );
+
+                InsertCommandArgument aArg;
+                aArg.Data = xStream;
+                aArg.ReplaceExisting = true;
+                m_pContent->executeCommand( "insert", Any(aArg) );
+
+                // wrapper now controls lifetime of temporary file
+                m_aTempURL.clear();
+
+                INetURLObject aObj( m_aURL );
+                aObj.setName( m_aName );
+                m_aURL = aObj.GetMainURL( INetURLObject::DecodeMechanism::NONE );
+                m_bModified = false;
+                m_bSourceRead = true;
+            }
+            catch (const CommandAbortedException&)
+            {
+                // any command wasn't executed successfully - not specified
+                SetError( ERRCODE_IO_GENERAL );
+                return COMMIT_RESULT_FAILURE;
+            }
+            catch (const RuntimeException&)
+            {
+                // any other error - not specified
+                SetError( ERRCODE_IO_GENERAL );
+                return COMMIT_RESULT_FAILURE;
+            }
+            catch (const Exception&)
+            {
+                // any other error - not specified
+                SetError( ERRCODE_IO_GENERAL );
+                return COMMIT_RESULT_FAILURE;
+            }
+
+            m_bCommited = false;
+            return COMMIT_RESULT_SUCCESS;
+        }
+    }
+
+    return COMMIT_RESULT_NOTHING_TO_DO;
+}
+
+void UCBStorageStream_Impl::Revert()
+{
+    // if an OLEStorage is created on this stream, no "revert" is necessary because OLEStorages do nothing on "Revert" !
+    if ( m_bCommited )
+    {
+        OSL_FAIL("Revert while commit is in progress!" );
+        return;                   //  ???
+    }
+
+    Free();
+    if ( !m_aTempURL.isEmpty() )
+    {
+        osl::File::remove(m_aTempURL);
+        m_aTempURL.clear();
+    }
+
+    m_bSourceRead = false;
+    try
+    {
+        m_rSource = m_pContent->openStream();
+        if( m_rSource.is() )
+        {
+            if ( m_pAntiImpl && ( m_nMode & StreamMode::TRUNC ) )
+                // stream is in use and should be truncated
+                m_bSourceRead = false;
+            else
+            {
+                m_nMode &= ~StreamMode::TRUNC;
+                m_bSourceRead = true;
+            }
+        }
+        else
+            SetError( SVSTREAM_CANNOT_MAKE );
+    }
+    catch (const ContentCreationException&)
+    {
+        SetError( ERRCODE_IO_GENERAL );
+    }
+    catch (const RuntimeException&)
+    {
+        SetError( ERRCODE_IO_GENERAL );
+    }
+    catch (const Exception&)
+    {
+    }
+
+    m_bModified = false;
+    m_aName = m_aOriginalName;
+    m_aContentType = m_aOriginalContentType;
+}
+
+bool UCBStorageStream_Impl::Clear()
+{
+    bool bRet = ( m_pAntiImpl == nullptr );
+    DBG_ASSERT( bRet, "Removing used stream!" );
+    if( bRet )
+    {
+        Free();
+    }
+
+    return bRet;
+}
+
+void UCBStorageStream_Impl::Free()
+{
+#if OSL_DEBUG_LEVEL > 0
+    if ( m_pStream )
+    {
+        if ( !m_aTempURL.isEmpty() )
+            --nOpenFiles;
+        else
+            --nOpenStreams;
+    }
+#endif
+
+    m_rSource.clear();
+    m_pStream.reset();
+}
+
+void UCBStorageStream_Impl::PrepareCachedForReopen( StreamMode nMode )
+{
+    bool isWritable = bool( m_nMode & StreamMode::WRITE );
+    if ( isWritable )
+    {
+        // once stream was writable, never reset to readonly
+        nMode |= StreamMode::WRITE;
+    }
+
+    m_nMode = nMode;
+    Free();
+
+    if ( nMode & StreamMode::TRUNC )
+    {
+        m_bSourceRead = false; // usually it should be 0 already but just in case...
+
+        if ( !m_aTempURL.isEmpty() )
+        {
+            osl::File::remove(m_aTempURL);
+            m_aTempURL.clear();
+        }
+    }
+}
+
+UCBStorageStream::UCBStorageStream( const OUString& rName, StreamMode nMode, bool bDirect, bool bRepair, Reference< XProgressHandler > const & xProgress )
+{
+    // pImp must be initialized in the body, because otherwise the vtable of the stream is not initialized
+    // to class UCBStorageStream !
+    pImp = new UCBStorageStream_Impl( rName, nMode, this, bDirect, bRepair, xProgress );
+    pImp->AddFirstRef();             // use direct refcounting because in header file only a pointer should be used
+    StorageBase::m_nMode = pImp->m_nMode;
+}
+
+UCBStorageStream::UCBStorageStream( UCBStorageStream_Impl *pImpl )
+    : pImp( pImpl )
+{
+    pImp->AddFirstRef();             // use direct refcounting because in header file only a pointer should be used
+    pImp->m_pAntiImpl = this;
+    SetError( pImp->m_nError );
+    StorageBase::m_nMode = pImp->m_nMode;
+}
+
+UCBStorageStream::~UCBStorageStream()
+{
+    if ( pImp->m_nMode & StreamMode::WRITE )
+        pImp->Flush();
+    pImp->m_pAntiImpl = nullptr;
+    pImp->Free();
+    pImp->ReleaseRef();
+}
+
+sal_Int32 UCBStorageStream::Read( void * pData, sal_Int32 nSize )
+{
+    //return pImp->m_pStream->Read( pData, nSize );
+    return pImp->GetData( pData, nSize );
+}
+
+sal_Int32 UCBStorageStream::Write( const void* pData, sal_Int32 nSize )
+{
+    return pImp->PutData( pData, nSize );
+}
+
+sal_uInt64 UCBStorageStream::Seek( sal_uInt64 nPos )
+{
+    //return pImp->m_pStream->Seek( nPos );
+    return pImp->Seek( nPos );
+}
+
+sal_uInt64 UCBStorageStream::Tell()
+{
+    if( !pImp->Init() )
+        return 0;
+    return pImp->m_pStream->Tell();
+}
+
+void UCBStorageStream::Flush()
+{
+    // streams are never really transacted, so flush also means commit !
+    Commit();
+}
+
+bool UCBStorageStream::SetSize( sal_uInt64 nNewSize )
+{
+    pImp->SetSize( nNewSize );
+    return !pImp->GetError();
+}
+
+bool UCBStorageStream::Validate( bool bWrite ) const
+{
+    return ( !bWrite || ( pImp->m_nMode & StreamMode::WRITE ) );
+}
+
+bool UCBStorageStream::ValidateMode( StreamMode m ) const
+{
+    // ???
+    if( m == ( StreamMode::READ | StreamMode::TRUNC ) )  // from stg.cxx
+        return true;
+    if( ( m & StreamMode::READWRITE) == StreamMode::READ )
+    {
+        // only SHARE_DENYWRITE or SHARE_DENYALL allowed
+        if( ( m & StreamMode::SHARE_DENYWRITE )
+         || ( m & StreamMode::SHARE_DENYALL ) )
+            return true;
+    }
+    else
+    {
+        // only SHARE_DENYALL allowed
+        // storages open in r/o mode are OK, since only
+        // the commit may fail
+        if( m & StreamMode::SHARE_DENYALL )
+            return true;
+    }
+
+    return true;
+}
+
+SvStream* UCBStorageStream::GetModifySvStream()
+{
+    return static_cast<SvStream*>(pImp);
+}
+
+bool  UCBStorageStream::Equals( const BaseStorageStream& rStream ) const
+{
+    // ???
+    return static_cast<BaseStorageStream const *>(this) == &rStream;
+}
+
+bool UCBStorageStream::Commit()
+{
+    // mark this stream for sending it on root commit
+    pImp->FlushData();
+    return true;
+}
+
+void UCBStorageStream::CopyTo( BaseStorageStream* pDestStm )
+{
+    if( !pImp->Init() )
+        return;
+
+    UCBStorageStream* pStg =  dynamic_cast<UCBStorageStream*>( pDestStm );
+    if ( pStg )
+        pStg->pImp->m_aContentType = pImp->m_aContentType;
+
+    pDestStm->SetSize( 0 );
+    Seek( STREAM_SEEK_TO_END );
+    sal_Int32 n = Tell();
+    if( n < 0 )
+        return;
+
+    if( !pDestStm->SetSize( n ) || !n )
+        return;
+
+    std::unique_ptr<sal_uInt8[]> p(new sal_uInt8[ 4096 ]);
+    Seek( 0 );
+    pDestStm->Seek( 0 );
+    while( n )
+    {
+        sal_Int32 nn = n;
+        if( nn > 4096 )
+            nn = 4096;
+        if( Read( p.get(), nn ) != nn )
+            break;
+        if( pDestStm->Write( p.get(), nn ) != nn )
+            break;
+        n -= nn;
+    }
+}
+
+bool UCBStorageStream::SetProperty( const OUString& rName, const css::uno::Any& rValue )
+{
+    if ( rName == "Title")
+        return false;
+
+    if ( rName == "MediaType")
+    {
+        OUString aTmp;
+        rValue >>= aTmp;
+        pImp->m_aContentType = aTmp;
+    }
+
+    try
+    {
+        if ( pImp->m_pContent )
+        {
+            pImp->m_pContent->setPropertyValue( rName, rValue );
+            return true;
+        }
+    }
+    catch (const Exception&)
+    {
+    }
+
+    return false;
+}
+
+sal_uInt64 UCBStorageStream::GetSize() const
+{
+    return pImp->GetSize();
+}
+
+UCBStorage::UCBStorage( SvStream& rStrm, bool bDirect )
+{
+    // pImp must be initialized in the body, because otherwise the vtable of the stream is not initialized
+    // to class UCBStorage !
+    pImp = new UCBStorage_Impl( rStrm, this, bDirect );
+
+    pImp->AddFirstRef();
+    pImp->Init();
+    StorageBase::m_nMode = pImp->m_nMode;
+}
+
+UCBStorage::UCBStorage( const ::ucbhelper::Content& rContent, const OUString& rName, StreamMode nMode, bool bDirect, bool bIsRoot )
+{
+    // pImp must be initialized in the body, because otherwise the vtable of the stream is not initialized
+    // to class UCBStorage !
+    pImp = new UCBStorage_Impl( rContent, rName, nMode, this, bDirect, bIsRoot );
+    pImp->AddFirstRef();
+    pImp->Init();
+    StorageBase::m_nMode = pImp->m_nMode;
+}
+
+UCBStorage::UCBStorage( const OUString& rName, StreamMode nMode, bool bDirect, bool bIsRoot, bool bIsRepair, Reference< XProgressHandler > const & xProgressHandler )
+{
+    // pImp must be initialized in the body, because otherwise the vtable of the stream is not initialized
+    // to class UCBStorage !
+    pImp = new UCBStorage_Impl( rName, nMode, this, bDirect, bIsRoot, bIsRepair, xProgressHandler );
+    pImp->AddFirstRef();
+    pImp->Init();
+    StorageBase::m_nMode = pImp->m_nMode;
+}
+
+UCBStorage::UCBStorage( const OUString& rName, StreamMode nMode, bool bDirect, bool bIsRoot )
+{
+    // pImp must be initialized in the body, because otherwise the vtable of the stream is not initialized
+    // to class UCBStorage !
+    pImp = new UCBStorage_Impl( rName, nMode, this, bDirect, bIsRoot, false, Reference< XProgressHandler >() );
+    pImp->AddFirstRef();
+    pImp->Init();
+    StorageBase::m_nMode = pImp->m_nMode;
+}
+
+UCBStorage::UCBStorage( UCBStorage_Impl *pImpl )
+    : pImp( pImpl )
+{
+    pImp->m_pAntiImpl = this;
+    SetError( pImp->m_nError );
+    pImp->AddFirstRef();             // use direct refcounting because in header file only a pointer should be used
+    StorageBase::m_nMode = pImp->m_nMode;
+}
+
+UCBStorage::~UCBStorage()
+{
+    if ( pImp->m_bIsRoot && pImp->m_bDirect && ( !pImp->m_pTempFile || pImp->m_pSource ) )
+        // DirectMode is simulated with an AutoCommit
+        Commit();
+
+    pImp->m_pAntiImpl = nullptr;
+    pImp->ReleaseRef();
+}
+
+UCBStorage_Impl::UCBStorage_Impl( const ::ucbhelper::Content& rContent, const OUString& rName, StreamMode nMode, UCBStorage* pStorage, bool bDirect, bool bIsRoot, bool bIsRepair, Reference< XProgressHandler > const & xProgressHandler  )
+    : m_pAntiImpl( pStorage )
+    , m_pContent( new ::ucbhelper::Content( rContent ) )
+    , m_pSource( nullptr )
+    //, m_pStream( NULL )
+    , m_nError( ERRCODE_NONE )
+    , m_nMode( nMode )
+    , m_bCommited( false )
+    , m_bDirect( bDirect )
+    , m_bIsRoot( bIsRoot )
+    , m_bIsLinked( true )
+    , m_bListCreated( false )
+    , m_nFormat( SotClipboardFormatId::NONE )
+    , m_bRepairPackage( bIsRepair )
+    , m_xProgressHandler( xProgressHandler )
+{
+    OUString aName( rName );
+    if( aName.isEmpty() )
+    {
+        // no name given = use temporary name!
+        DBG_ASSERT( m_bIsRoot, "SubStorage must have a name!" );
+        m_pTempFile.reset(new ::utl::TempFile);
+        m_pTempFile->EnableKillingFile();
+        m_aName = aName = m_pTempFile->GetURL();
+    }
+
+    m_aURL = rName;
+}
+
+UCBStorage_Impl::UCBStorage_Impl( const OUString& rName, StreamMode nMode, UCBStorage* pStorage, bool bDirect, bool bIsRoot, bool bIsRepair, Reference< XProgressHandler > const & xProgressHandler )
+    : m_pAntiImpl( pStorage )
+    , m_pSource( nullptr )
+    //, m_pStream( NULL )
+    , m_nError( ERRCODE_NONE )
+    , m_nMode( nMode )
+    , m_bCommited( false )
+    , m_bDirect( bDirect )
+    , m_bIsRoot( bIsRoot )
+    , m_bIsLinked( false )
+    , m_bListCreated( false )
+    , m_nFormat( SotClipboardFormatId::NONE )
+    , m_bRepairPackage( bIsRepair )
+    , m_xProgressHandler( xProgressHandler )
+{
+    OUString aName( rName );
+    if( aName.isEmpty() )
+    {
+        // no name given = use temporary name!
+        DBG_ASSERT( m_bIsRoot, "SubStorage must have a name!" );
+        m_pTempFile.reset(new ::utl::TempFile);
+        m_pTempFile->EnableKillingFile();
+        m_aName = aName = m_pTempFile->GetURL();
+    }
+
+    if ( m_bIsRoot )
+    {
+        // create the special package URL for the package content
+        m_aURL = "vnd.sun.star.pkg://" +
+            INetURLObject::encode( aName, INetURLObject::PART_AUTHORITY, INetURLObject::EncodeMechanism::All );
+
+        if ( m_nMode & StreamMode::WRITE )
+        {
+            // the root storage opens the package, so make sure that there is any
+            ::utl::UcbStreamHelper::CreateStream( aName, StreamMode::STD_READWRITE, m_pTempFile != nullptr /* bFileExists */ );
+        }
+    }
+    else
+    {
+        // substorages are opened like streams: the URL is a "child URL" of the root package URL
+        m_aURL = rName;
+        if ( !m_aURL.startsWith( "vnd.sun.star.pkg://") )
+            m_bIsLinked = true;
+    }
+}
+
+UCBStorage_Impl::UCBStorage_Impl( SvStream& rStream, UCBStorage* pStorage, bool bDirect )
+    : m_pAntiImpl( pStorage )
+    , m_pTempFile( new ::utl::TempFile )
+    , m_pSource( &rStream )
+    , m_nError( ERRCODE_NONE )
+    , m_bCommited( false )
+    , m_bDirect( bDirect )
+    , m_bIsRoot( true )
+    , m_bIsLinked( false )
+    , m_bListCreated( false )
+    , m_nFormat( SotClipboardFormatId::NONE )
+    , m_bRepairPackage( false )
+{
+    // opening in direct mode is too fuzzy because the data is transferred to the stream in the Commit() call,
+    // which will be called in the storages' dtor
+    m_pTempFile->EnableKillingFile();
+    DBG_ASSERT( !bDirect, "Storage on a stream must not be opened in direct mode!" );
+
+    // UCBStorages work on a content, so a temporary file for a content must be created, even if the stream is only
+    // accessed readonly
+    // the root storage opens the package; create the special package URL for the package content
+    m_aURL = "vnd.sun.star.pkg://" +
+        INetURLObject::encode( m_pTempFile->GetURL(), INetURLObject::PART_AUTHORITY, INetURLObject::EncodeMechanism::All );
+
+    // copy data into the temporary file
+    std::unique_ptr<SvStream> pStream(::utl::UcbStreamHelper::CreateStream( m_pTempFile->GetURL(), StreamMode::STD_READWRITE, true /* bFileExists */ ));
+    if ( pStream )
+    {
+        rStream.Seek(0);
+        rStream.ReadStream( *pStream );
+        pStream->Flush();
+        pStream.reset();
+    }
+
+    // close stream and let content access the file
+    m_pSource->Seek(0);
+
+    // check opening mode
+    m_nMode = StreamMode::READ;
+    if( rStream.IsWritable() )
+        m_nMode = StreamMode::READ | StreamMode::WRITE;
+}
+
+void UCBStorage_Impl::Init()
+{
+    // name is last segment in URL
+    INetURLObject aObj( m_aURL );
+    if ( m_aName.isEmpty() )
+        // if the name was not already set to a temp name
+        m_aName = aObj.GetLastName();
+
+    if ( !m_pContent )
+        CreateContent();
+
+    if ( m_pContent )
+    {
+        if ( m_bIsLinked )
+        {
+            if( m_bIsRoot )
+            {
+                ReadContent();
+                if ( m_nError == ERRCODE_NONE )
+                {
+                    // read the manifest.xml file
+                    aObj.Append( u"META-INF" );
+                    aObj.Append( u"manifest.xml" );
+
+                    // create input stream
+                    std::unique_ptr<SvStream> pStream(::utl::UcbStreamHelper::CreateStream( aObj.GetMainURL( INetURLObject::DecodeMechanism::NONE ), StreamMode::STD_READ ));
+                    // no stream means no manifest.xml
+                    if ( pStream )
+                    {
+                        if ( !pStream->GetError() )
+                        {
+                            rtl::Reference<::utl::OInputStreamWrapper> pHelper = new ::utl::OInputStreamWrapper( *pStream );
+
+                            // create a manifest reader object that will read in the manifest from the stream
+                            Reference < css::packages::manifest::XManifestReader > xReader =
+                                css::packages::manifest::ManifestReader::create(
+                                    ::comphelper::getProcessComponentContext() ) ;
+                            Sequence < Sequence < PropertyValue > > aProps = xReader->readManifestSequence( pHelper );
+
+                            // cleanup
+                            xReader = nullptr;
+                            pHelper = nullptr;
+                            SetProps( aProps, OUString() );
+                        }
+                    }
+                }
+            }
+            else
+                ReadContent();
+        }
+        else
+        {
+            // get the manifest information from the package
+            try {
+                Any aAny = m_pContent->getPropertyValue("MediaType");
+                OUString aTmp;
+                if ( ( aAny >>= aTmp ) && !aTmp.isEmpty() )
+                    m_aContentType = m_aOriginalContentType = aTmp;
+            }
+            catch (const Exception&)
+            {
+                SAL_WARN( "sot",
+                          "getPropertyValue has thrown an exception! Please let developers know the scenario!" );
+            }
+        }
+    }
+
+    if ( m_aContentType.isEmpty() )
+        return;
+
+    // get the clipboard format using the content type
+    css::datatransfer::DataFlavor aDataFlavor;
+    aDataFlavor.MimeType = m_aContentType;
+    m_nFormat = SotExchange::GetFormat( aDataFlavor );
+
+    // get the ClassId using the clipboard format ( internal table )
+    m_aClassId = GetClassId_Impl( m_nFormat );
+
+    // get human presentable name using the clipboard format
+    SotExchange::GetFormatDataFlavor( m_nFormat, aDataFlavor );
+    m_aUserTypeName = aDataFlavor.HumanPresentableName;
+
+    if( m_pContent && !m_bIsLinked && m_aClassId != SvGlobalName() )
+        ReadContent();
+}
+
+void UCBStorage_Impl::CreateContent()
+{
+    try
+    {
+        // create content; where to put StreamMode ?! ( already done when opening the file of the package ? )
+        Reference< css::ucb::XCommandEnvironment > xComEnv;
+
+        OUString aTemp( m_aURL );
+
+        if ( m_bRepairPackage )
+        {
+            xComEnv = new ::ucbhelper::CommandEnvironment( Reference< css::task::XInteractionHandler >(),
+                                                     m_xProgressHandler );
+            aTemp += "?repairpackage";
+        }
+
+        m_pContent.reset(new ::ucbhelper::Content( aTemp, xComEnv, comphelper::getProcessComponentContext() ));
+    }
+    catch (const ContentCreationException&)
+    {
+        // content could not be created
+        SetError( SVSTREAM_CANNOT_MAKE );
+    }
+    catch (const RuntimeException&)
+    {
+        // any other error - not specified
+        SetError( SVSTREAM_CANNOT_MAKE );
+    }
+}
+
+void UCBStorage_Impl::ReadContent()
+{
+    if ( m_bListCreated )
+        return;
+
+    m_bListCreated = true;
+
+    try
+    {
+        GetContent();
+        if ( !m_pContent )
+            return;
+
+        // create cursor for access to children
+        Reference< XResultSet > xResultSet = m_pContent->createCursor( { "Title", "IsFolder", "MediaType", "Size" }, ::ucbhelper::INCLUDE_FOLDERS_AND_DOCUMENTS );
+        Reference< XRow > xRow( xResultSet, UNO_QUERY );
+        if ( xResultSet.is() )
+        {
+            while ( xResultSet->next() )
+            {
+                // insert all into the children list
+                OUString aTitle( xRow->getString(1) );
+                if ( m_bIsLinked )
+                {
+                    // unpacked storages have to deal with the meta-inf folder by themselves
+                    if ( aTitle == "META-INF" )
+                        continue;
+                }
+
+                bool bIsFolder( xRow->getBoolean(2) );
+                sal_Int64 nSize = xRow->getLong(4);
+                UCBStorageElement_Impl* pElement = new UCBStorageElement_Impl( aTitle, bIsFolder, nSize );
+                m_aChildrenList.emplace_back( pElement );
+
+                bool bIsOfficeDocument = m_bIsLinked || ( m_aClassId != SvGlobalName() );
+                if ( bIsFolder )
+                {
+                    if ( m_bIsLinked )
+                        OpenStorage( pElement, m_nMode, m_bDirect );
+                    if ( pElement->m_xStorage.is() )
+                        pElement->m_xStorage->Init();
+                }
+                else if ( bIsOfficeDocument )
+                {
+                    // streams can be external OLE objects, so they are now folders, but storages!
+                    OUString aName( m_aURL + "/" + xRow->getString(1));
+
+                    Reference< css::ucb::XCommandEnvironment > xComEnv;
+                    if ( m_bRepairPackage )
+                    {
+                        xComEnv = new ::ucbhelper::CommandEnvironment( Reference< css::task::XInteractionHandler >(),
+                                                                m_xProgressHandler );
+                        aName += "?repairpackage";
+                    }
+
+                    ::ucbhelper::Content aContent( aName, xComEnv, comphelper::getProcessComponentContext() );
+
+                    OUString aMediaType;
+                    Any aAny = aContent.getPropertyValue("MediaType");
+                    if ( ( aAny >>= aMediaType ) && ( aMediaType == "application/vnd.sun.star.oleobject" ) )
+                        pElement->m_bIsStorage = true;
+                    else if ( aMediaType.isEmpty() )
+                    {
+                        // older files didn't have that special content type, so they must be detected
+                        OpenStream( pElement, StreamMode::STD_READ, m_bDirect );
+                        if ( Storage::IsStorageFile( pElement->m_xStream.get() ) )
+                            pElement->m_bIsStorage = true;
+                        else
+                            pElement->m_xStream->Free();
+                    }
+                }
+            }
+        }
+    }
+    catch (const InteractiveIOException& r)
+    {
+        if ( r.Code != IOErrorCode_NOT_EXISTING )
+            SetError( ERRCODE_IO_GENERAL );
+    }
+    catch (const CommandAbortedException&)
+    {
+        // any command wasn't executed successfully - not specified
+        if ( !( m_nMode & StreamMode::WRITE ) )
+            // if the folder was just inserted and not already committed, this is not an error!
+            SetError( ERRCODE_IO_GENERAL );
+    }
+    catch (const RuntimeException&)
+    {
+        // any other error - not specified
+        SetError( ERRCODE_IO_GENERAL );
+    }
+    catch (const ResultSetException&)
+    {
+        // means that the package file is broken
+        SetError( ERRCODE_IO_BROKENPACKAGE );
+    }
+    catch (const SQLException&)
+    {
+        // means that the file can be broken
+        SetError( ERRCODE_IO_WRONGFORMAT );
+    }
+    catch (const Exception&)
+    {
+        // any other error - not specified
+        SetError( ERRCODE_IO_GENERAL );
+    }
+}
+
+void UCBStorage_Impl::SetError( ErrCode nError )
+{
+    if ( !m_nError )
+    {
+        m_nError = nError;
+        if ( m_pAntiImpl ) m_pAntiImpl->SetError( nError );
+    }
+}
+
+sal_Int32 UCBStorage_Impl::GetObjectCount()
+{
+    sal_Int32 nCount = m_aChildrenList.size();
+    for (auto& pElement : m_aChildrenList)
+    {
+        DBG_ASSERT( !pElement->m_bIsFolder || pElement->m_xStorage.is(), "Storage should be open!" );
+        if ( pElement->m_bIsFolder && pElement->m_xStorage.is() )
+            nCount += pElement->m_xStorage->GetObjectCount();
+    }
+
+    return nCount;
+}
+
+static OUString Find_Impl( const Sequence < Sequence < PropertyValue > >& rSequence, std::u16string_view rPath )
+{
+    bool bFound = false;
+    for ( const Sequence < PropertyValue >& rMyProps : rSequence )
+    {
+        OUString aType;
+
+        for ( const PropertyValue& rAny : rMyProps )
+        {
+            if ( rAny.Name == "FullPath" )
+            {
+                OUString aTmp;
+                if ( ( rAny.Value >>= aTmp ) && aTmp == rPath )
+                    bFound = true;
+                if ( !aType.isEmpty() )
+                    break;
+            }
+            else if ( rAny.Name == "MediaType" )
+            {
+                if ( ( rAny.Value >>= aType ) && !aType.isEmpty() && bFound )
+                    break;
+            }
+        }
+
+        if ( bFound )
+            return aType;
+    }
+
+    return OUString();
+}
+
+void UCBStorage_Impl::SetProps( const Sequence < Sequence < PropertyValue > >& rSequence, const OUString& rPath )
+{
+    OUString aPath( rPath );
+    if ( !m_bIsRoot )
+        aPath += m_aName;
+    aPath += "/";
+
+    m_aContentType = m_aOriginalContentType = Find_Impl( rSequence, aPath );
+
+    if ( m_bIsRoot )
+        // the "FullPath" of a child always starts without '/'
+        aPath.clear();
+
+    for (auto& pElement : m_aChildrenList)
+    {
+        DBG_ASSERT( !pElement->m_bIsFolder || pElement->m_xStorage.is(), "Storage should be open!" );
+        if ( pElement->m_bIsFolder && pElement->m_xStorage.is() )
+            pElement->m_xStorage->SetProps( rSequence, aPath );
+        else
+        {
+            OUString aElementPath = aPath + pElement->m_aName;
+            pElement->SetContentType( Find_Impl( rSequence, aElementPath ) );
+        }
+    }
+
+    if ( m_aContentType.isEmpty() )
+        return;
+
+    // get the clipboard format using the content type
+    css::datatransfer::DataFlavor aDataFlavor;
+    aDataFlavor.MimeType = m_aContentType;
+    m_nFormat = SotExchange::GetFormat( aDataFlavor );
+
+    // get the ClassId using the clipboard format ( internal table )
+    m_aClassId = GetClassId_Impl( m_nFormat );
+
+    // get human presentable name using the clipboard format
+    SotExchange::GetFormatDataFlavor( m_nFormat, aDataFlavor );
+    m_aUserTypeName = aDataFlavor.HumanPresentableName;
+}
+
+void UCBStorage_Impl::GetProps( sal_Int32& nProps, Sequence < Sequence < PropertyValue > >& rSequence, const OUString& rPath )
+{
+    auto pSequence = rSequence.getArray();
+
+    // first my own properties
+    // first property is the "FullPath" name
+    // it's '/' for the root storage and m_aName for each element, followed by a '/' if it's a folder
+    OUString aPath( rPath );
+    if ( !m_bIsRoot )
+        aPath += m_aName;
+    aPath += "/";
+    Sequence < PropertyValue > aProps{ comphelper::makePropertyValue("MediaType", m_aContentType),
+                                       comphelper::makePropertyValue("FullPath", aPath) };
+    pSequence[nProps++] = aProps;
+
+    if ( m_bIsRoot )
+        // the "FullPath" of a child always starts without '/'
+        aPath.clear();
+
+    // now the properties of my elements
+    for (auto& pElement : m_aChildrenList)
+    {
+        DBG_ASSERT( !pElement->m_bIsFolder || pElement->m_xStorage.is(), "Storage should be open!" );
+        if ( pElement->m_bIsFolder && pElement->m_xStorage.is() )
+            // storages add there properties by themselves ( see above )
+            pElement->m_xStorage->GetProps( nProps, rSequence, aPath );
+        else
+        {
+            // properties of streams
+            OUString aElementPath = aPath + pElement->m_aName;
+            aProps = { comphelper::makePropertyValue("MediaType", pElement->GetContentType()),
+                       comphelper::makePropertyValue("FullPath", aElementPath) };
+            pSequence[ nProps++ ] = aProps;
+        }
+    }
+}
+
+UCBStorage_Impl::~UCBStorage_Impl()
+{
+    m_aChildrenList.clear();
+
+    m_pContent.reset();
+    m_pTempFile.reset();
+}
+
+bool UCBStorage_Impl::Insert( ::ucbhelper::Content *pContent )
+{
+    // a new substorage is inserted into a UCBStorage ( given by the parameter pContent )
+    // it must be inserted with a title and a type
+    bool bRet = false;
+
+    try
+    {
+        const Sequence< ContentInfo > aInfo = pContent->queryCreatableContentsInfo();
+        if ( !aInfo.hasElements() )
+            return false;
+
+        for ( const ContentInfo & rCurr : aInfo )
+        {
+            // Simply look for the first KIND_FOLDER...
+            if ( rCurr.Attributes & ContentInfoAttribute::KIND_FOLDER )
+            {
+                // Make sure the only required bootstrap property is "Title",
+                const Sequence< Property > & rProps = rCurr.Properties;
+                if ( rProps.getLength() != 1 )
+                    continue;
+
+                if ( rProps[ 0 ].Name != "Title" )
+                    continue;
+
+                Content aNewFolder;
+                if ( !pContent->insertNewContent( rCurr.Type, { "Title" }, { Any(m_aName) }, aNewFolder ) )
+                    continue;
+
+                // remove old content, create an "empty" new one and initialize it with the new inserted
+                m_pContent.reset(new ::ucbhelper::Content( aNewFolder ));
+                bRet = true;
+            }
+        }
+    }
+    catch (const CommandAbortedException&)
+    {
+        // any command wasn't executed successfully - not specified
+        SetError( ERRCODE_IO_GENERAL );
+    }
+    catch (const RuntimeException&)
+    {
+        // any other error - not specified
+        SetError( ERRCODE_IO_GENERAL );
+    }
+    catch (const Exception&)
+    {
+        // any other error - not specified
+        SetError( ERRCODE_IO_GENERAL );
+    }
+
+    return bRet;
+}
+
+sal_Int16 UCBStorage_Impl::Commit()
+{
+    // send all changes to the package
+    sal_Int16 nRet = COMMIT_RESULT_NOTHING_TO_DO;
+
+    // there is nothing to do if the storage has been opened readonly or if it was opened in transacted mode and no
+    // commit command has been sent
+    if ( ( m_nMode & StreamMode::WRITE ) && ( m_bCommited || m_bDirect ) )
+    {
+        try
+        {
+            // all errors will be caught in the "catch" statement outside the loop
+            for ( size_t i = 0; i < m_aChildrenList.size() && nRet; ++i )
+            {
+                auto& pElement = m_aChildrenList[ i ];
+                ::ucbhelper::Content* pContent = pElement->GetContent();
+                std::unique_ptr< ::ucbhelper::Content > xDeleteContent;
+                if ( !pContent && pElement->IsModified() )
+                {
+                    // if the element has never been opened, no content has been created until now
+                    OUString aName = m_aURL + "/" + pElement->m_aOriginalName;
+                    pContent = new ::ucbhelper::Content( aName, Reference< css::ucb::XCommandEnvironment >(), comphelper::getProcessComponentContext() );
+                    xDeleteContent.reset(pContent);  // delete it later on exit scope
+                }
+
+                if ( pElement->m_bIsRemoved )
+                {
+                    // was it inserted, then removed (so there would be nothing to do!)
+                    if ( !pElement->m_bIsInserted )
+                    {
+                        // first remove all open stream handles
+                        if (pContent && (!pElement->m_xStream.is() || pElement->m_xStream->Clear()))
+                        {
+                            pContent->executeCommand( "delete", Any( true ) );
+                            nRet = COMMIT_RESULT_SUCCESS;
+                        }
+                        else
+                            // couldn't release stream because there are external references to it
+                            nRet = COMMIT_RESULT_FAILURE;
+                    }
+                }
+                else
+                {
+                    sal_Int16 nLocalRet = COMMIT_RESULT_NOTHING_TO_DO;
+                    if ( pElement->m_xStorage.is() )
+                    {
+                        // element is a storage
+                        // do a commit in the following cases:
+                        //  - if storage is already inserted, and changed
+                        //  - storage is not in a package
+                        //  - it's a new storage, try to insert and commit if successful inserted
+                        if ( !pElement->m_bIsInserted || m_bIsLinked || pElement->m_xStorage->Insert( m_pContent.get() ) )
+                        {
+                            nLocalRet = pElement->m_xStorage->Commit();
+                            pContent = pElement->GetContent();
+                        }
+                    }
+                    else if ( pElement->m_xStream.is() )
+                    {
+                        // element is a stream
+                        nLocalRet = pElement->m_xStream->Commit();
+                        if ( pElement->m_xStream->m_bIsOLEStorage )
+                        {
+                            // OLE storage should be stored encrypted, if the storage uses encryption
+                            pElement->m_xStream->m_aContentType = "application/vnd.sun.star.oleobject";
+                            Any aValue;
+                            aValue <<= true;
+                            pElement->m_xStream->m_pContent->setPropertyValue("Encrypted", aValue );
+                        }
+
+                        pContent = pElement->GetContent();
+                    }
+
+                    if (pContent && pElement->m_aName != pElement->m_aOriginalName)
+                    {
+                        // name ( title ) of the element was changed
+                        nLocalRet = COMMIT_RESULT_SUCCESS;
+                        pContent->setPropertyValue("Title", Any(pElement->m_aName) );
+                    }
+
+                    if (pContent && pElement->IsLoaded() && pElement->GetContentType() != pElement->GetOriginalContentType())
+                    {
+                        // mediatype of the element was changed
+                        nLocalRet = COMMIT_RESULT_SUCCESS;
+                        pContent->setPropertyValue("MediaType", Any(pElement->GetContentType()) );
+                    }
+
+                    if ( nLocalRet != COMMIT_RESULT_NOTHING_TO_DO )
+                        nRet = nLocalRet;
+                }
+
+                if ( nRet == COMMIT_RESULT_FAILURE )
+                    break;
+            }
+        }
+        catch (const ContentCreationException&)
+        {
+            // content could not be created
+            SetError( ERRCODE_IO_NOTEXISTS );
+            return COMMIT_RESULT_FAILURE;
+        }
+        catch (const CommandAbortedException&)
+        {
+            // any command wasn't executed successfully - not specified
+            SetError( ERRCODE_IO_GENERAL );
+            return COMMIT_RESULT_FAILURE;
+        }
+        catch (const RuntimeException&)
+        {
+            // any other error - not specified
+            SetError( ERRCODE_IO_GENERAL );
+            return COMMIT_RESULT_FAILURE;
+        }
+        catch (const Exception&)
+        {
+            // any other error - not specified
+            SetError( ERRCODE_IO_GENERAL );
+            return COMMIT_RESULT_FAILURE;
+        }
+
+        if ( m_bIsRoot && m_pContent )
+        {
+            // the root storage must flush the root package content
+            if ( nRet == COMMIT_RESULT_SUCCESS )
+            {
+                try
+                {
+                    // commit the media type to the JAR file
+                    // clipboard format and ClassId will be retrieved from the media type when the file is loaded again
+                    Any aType;
+                    aType <<= m_aContentType;
+                    m_pContent->setPropertyValue("MediaType", aType );
+
+                    if (  m_bIsLinked )
+                    {
+                        // write a manifest file
+                        // first create a subfolder "META-inf"
+                        Content aNewSubFolder;
+                        bool bRet = ::utl::UCBContentHelper::MakeFolder( *m_pContent, "META-INF", aNewSubFolder );
+                        if ( bRet )
+                        {
+                            // create a stream to write the manifest file - use a temp file
+                            OUString aURL( aNewSubFolder.getURL() );
+                            std::optional< ::utl::TempFile> pTempFile(&aURL );
+
+                            // get the stream from the temp file and create an output stream wrapper
+                            SvStream* pStream = pTempFile->GetStream( StreamMode::STD_READWRITE );
+                            rtl::Reference<::utl::OOutputStreamWrapper> xOutputStream = new ::utl::OOutputStreamWrapper( *pStream );
+
+                            // create a manifest writer object that will fill the stream
+                            Reference < css::packages::manifest::XManifestWriter > xWriter =
+                                css::packages::manifest::ManifestWriter::create(
+                                    ::comphelper::getProcessComponentContext() );
+                            sal_Int32 nCount = GetObjectCount() + 1;
+                            Sequence < Sequence < PropertyValue > > aProps( nCount );
+                            sal_Int32 nProps = 0;
+                            GetProps( nProps, aProps, OUString() );
+                            xWriter->writeManifestSequence( xOutputStream, aProps );
+
+                            // move the stream to its desired location
+                            Content aSource( pTempFile->GetURL(), Reference < XCommandEnvironment >(), comphelper::getProcessComponentContext() );
+                            xWriter = nullptr;
+                            xOutputStream = nullptr;
+                            pTempFile.reset();
+                            aNewSubFolder.transferContent( aSource, InsertOperation::Move, "manifest.xml", NameClash::OVERWRITE );
+                        }
+                    }
+                    else
+                    {
+#if OSL_DEBUG_LEVEL > 0
+                        SAL_INFO("sot", "Files: " << nOpenFiles);
+                        SAL_INFO("sot", "Streams: " << nOpenStreams);
+#endif
+                        // force writing
+                        Any aAny;
+                        m_pContent->executeCommand( "flush", aAny );
+                        if ( m_pSource != nullptr )
+                        {
+                            std::unique_ptr<SvStream> pStream(::utl::UcbStreamHelper::CreateStream( m_pTempFile->GetURL(), StreamMode::STD_READ ));
+                            m_pSource->SetStreamSize(0);
+                            // m_pSource->Seek(0);
+                            pStream->ReadStream( *m_pSource );
+                            pStream.reset();
+                            m_pSource->Seek(0);
+                        }
+                    }
+                }
+                catch (const CommandAbortedException&)
+                {
+                    // how to tell the content : forget all changes ?!
+                    // or should we assume that the content does it by itself because he threw an exception ?!
+                    // any command wasn't executed successfully - not specified
+                    SetError( ERRCODE_IO_GENERAL );
+                    return COMMIT_RESULT_FAILURE;
+                }
+                catch (const RuntimeException&)
+                {
+                    // how to tell the content : forget all changes ?!
+                    // or should we assume that the content does it by itself because he threw an exception ?!
+                    // any other error - not specified
+                    SetError( ERRCODE_IO_GENERAL );
+                    return COMMIT_RESULT_FAILURE;
+                }
+                catch (const InteractiveIOException& r)
+                {
+                    if ( r.Code == IOErrorCode_ACCESS_DENIED || r.Code == IOErrorCode_LOCKING_VIOLATION )
+                        SetError( ERRCODE_IO_ACCESSDENIED );
+                    else if ( r.Code == IOErrorCode_NOT_EXISTING )
+                        SetError( ERRCODE_IO_NOTEXISTS );
+                    else if ( r.Code == IOErrorCode_CANT_READ )
+                        SetError( ERRCODE_IO_CANTREAD );
+                    else if ( r.Code == IOErrorCode_CANT_WRITE )
+                        SetError( ERRCODE_IO_CANTWRITE );
+                    else
+                        SetError( ERRCODE_IO_GENERAL );
+
+                    return COMMIT_RESULT_FAILURE;
+                }
+                catch (const Exception&)
+                {
+                    // how to tell the content : forget all changes ?!
+                    // or should we assume that the content does it by itself because he threw an exception ?!
+                    // any other error - not specified
+                    SetError( ERRCODE_IO_GENERAL );
+                    return COMMIT_RESULT_FAILURE;
+                }
+            }
+            else if ( nRet != COMMIT_RESULT_NOTHING_TO_DO )
+            {
+                // how to tell the content : forget all changes ?! Should we ?!
+                SetError( ERRCODE_IO_GENERAL );
+                return nRet;
+            }
+
+            // after successful root commit all elements names and types are adjusted and all removed elements
+            // are also removed from the lists
+            for ( size_t i = 0; i < m_aChildrenList.size(); )
+            {
+                auto& pInnerElement = m_aChildrenList[ i ];
+                if ( pInnerElement->m_bIsRemoved )
+                    m_aChildrenList.erase( m_aChildrenList.begin() + i );
+                else
+                {
+                    pInnerElement->m_aOriginalName = pInnerElement->m_aName;
+                    pInnerElement->m_bIsInserted = false;
+                    ++i;
+                }
+            }
+        }
+
+        m_bCommited = false;
+    }
+
+    return nRet;
+}
+
+void UCBStorage_Impl::Revert()
+{
+    for ( size_t i = 0; i < m_aChildrenList.size(); )
+    {
+        auto& pElement = m_aChildrenList[ i ];
+        pElement->m_bIsRemoved = false;
+        if ( pElement->m_bIsInserted )
+            m_aChildrenList.erase( m_aChildrenList.begin() + i );
+        else
+        {
+            if ( pElement->m_xStream.is() )
+            {
+                pElement->m_xStream->m_bCommited = false;
+                pElement->m_xStream->Revert();
+            }
+            else if ( pElement->m_xStorage.is() )
+            {
+                pElement->m_xStorage->m_bCommited = false;
+                pElement->m_xStorage->Revert();
+            }
+
+            pElement->m_aName = pElement->m_aOriginalName;
+            pElement->m_bIsRemoved = false;
+            ++i;
+        }
+    }
+}
+
+const OUString& UCBStorage::GetName() const
+{
+    return pImp->m_aName; // pImp->m_aURL ?!
+}
+
+bool UCBStorage::IsRoot() const
+{
+    return pImp->m_bIsRoot;
+}
+
+void UCBStorage::SetDirty()
+{
+}
+
+void UCBStorage::SetClass( const SvGlobalName & rClass, SotClipboardFormatId nOriginalClipFormat, const OUString & rUserTypeName )
+{
+    pImp->m_aClassId = rClass;
+    pImp->m_nFormat = nOriginalClipFormat;
+    pImp->m_aUserTypeName = rUserTypeName;
+
+    // in UCB storages only the content type will be stored, all other information can be reconstructed
+    // ( see the UCBStorage_Impl::Init() method )
+    css::datatransfer::DataFlavor aDataFlavor;
+    SotExchange::GetFormatDataFlavor( pImp->m_nFormat, aDataFlavor );
+    pImp->m_aContentType = aDataFlavor.MimeType;
+}
+
+void UCBStorage::SetClassId( const ClsId& rClsId )
+{
+    pImp->m_aClassId = SvGlobalName( rClsId );
+    if ( pImp->m_aClassId == SvGlobalName() )
+        return;
+
+    // in OLE storages the clipboard format and the user name will be transferred when a storage is copied because both are
+    // stored in one the substreams
+    // UCB storages store the content type information as content type in the manifest file and so this information must be
+    // kept up to date, and also the other type information that is hold only at runtime because it can be reconstructed from
+    // the content type
+    pImp->m_nFormat = GetFormatId_Impl( pImp->m_aClassId );
+    if ( pImp->m_nFormat != SotClipboardFormatId::NONE )
+    {
+        css::datatransfer::DataFlavor aDataFlavor;
+        SotExchange::GetFormatDataFlavor( pImp->m_nFormat, aDataFlavor );
+        pImp->m_aUserTypeName = aDataFlavor.HumanPresentableName;
+        pImp->m_aContentType = aDataFlavor.MimeType;
+    }
+}
+
+const ClsId& UCBStorage::GetClassId() const
+{
+    return pImp->m_aClassId.GetCLSID();
+}
+
+SvGlobalName UCBStorage::GetClassName()
+{
+    return  pImp->m_aClassId;
+}
+
+SotClipboardFormatId UCBStorage::GetFormat()
+{
+    return pImp->m_nFormat;
+}
+
+OUString UCBStorage::GetUserName()
+{
+    OSL_FAIL("UserName is not implemented in UCB storages!" );
+    return pImp->m_aUserTypeName;
+}
+
+void UCBStorage::FillInfoList( SvStorageInfoList* pList ) const
+{
+    // put information in childrenlist into StorageInfoList
+    for (auto& pElement : pImp->GetChildrenList())
+    {
+        if ( !pElement->m_bIsRemoved )
+        {
+            // problem: what about the size of a substorage ?!
+            sal_uInt64 nSize = pElement->m_nSize;
+            if ( pElement->m_xStream.is() )
+                nSize = pElement->m_xStream->GetSize();
+            SvStorageInfo aInfo( pElement->m_aName, nSize, pElement->m_bIsStorage );
+            pList->push_back( aInfo );
+        }
+    }
+}
+
+bool UCBStorage::CopyStorageElement_Impl( UCBStorageElement_Impl const & rElement, BaseStorage* pDest, const OUString& rNew ) const
+{
+    // insert stream or storage into the list or stream of the destination storage
+    // not into the content, this will be done on commit !
+    // be aware of name changes !
+    if ( !rElement.m_bIsStorage )
+    {
+        // copy the streams data
+        // the destination stream must not be open
+        tools::SvRef<BaseStorageStream> pOtherStream(pDest->OpenStream( rNew, StreamMode::WRITE | StreamMode::SHARE_DENYALL, pImp->m_bDirect ));
+        BaseStorageStream* pStream = nullptr;
+        bool bDeleteStream = false;
+
+        // if stream is already open, it is allowed to copy it, so be aware of this
+        if ( rElement.m_xStream.is() )
+            pStream = rElement.m_xStream->m_pAntiImpl;
+        if ( !pStream )
+        {
+            pStream = const_cast< UCBStorage* >(this)->OpenStream( rElement.m_aName, StreamMode::STD_READ, pImp->m_bDirect );
+            bDeleteStream = true;
+        }
+
+        pStream->CopyTo( pOtherStream.get() );
+        SetError( pStream->GetError() );
+        if( pOtherStream->GetError() )
+            pDest->SetError( pOtherStream->GetError() );
+        else
+            pOtherStream->Commit();
+
+        if ( bDeleteStream )
+            delete pStream;
+    }
+    else
+    {
+        // copy the storage content
+        // the destination storage must not be open
+        BaseStorage* pStorage = nullptr;
+
+        // if stream is already open, it is allowed to copy it, so be aware of this
+        bool bDeleteStorage = false;
+        if ( rElement.m_xStorage.is() )
+            pStorage = rElement.m_xStorage->m_pAntiImpl;
+        if ( !pStorage )
+        {
+            pStorage = const_cast<UCBStorage*>(this)->OpenStorage( rElement.m_aName, pImp->m_nMode, pImp->m_bDirect );
+            bDeleteStorage = true;
+        }
+
+        UCBStorage* pUCBDest =  dynamic_cast<UCBStorage*>( pDest );
+        UCBStorage* pUCBCopy =  dynamic_cast<UCBStorage*>( pStorage );
+
+        bool bOpenUCBStorage = pUCBDest && pUCBCopy;
+        tools::SvRef<BaseStorage> pOtherStorage(bOpenUCBStorage ?
+                pDest->OpenUCBStorage( rNew, StreamMode::WRITE | StreamMode::SHARE_DENYALL, pImp->m_bDirect ) :
+                pDest->OpenOLEStorage( rNew, StreamMode::WRITE | StreamMode::SHARE_DENYALL, pImp->m_bDirect ));
+
+        // For UCB storages, the class id and the format id may differ,
+        // do passing the class id is not sufficient.
+        if( bOpenUCBStorage )
+            pOtherStorage->SetClass( pStorage->GetClassName(),
+                                     pStorage->GetFormat(),
+                                     pUCBCopy->pImp->m_aUserTypeName );
+        else
+            pOtherStorage->SetClassId( pStorage->GetClassId() );
+        pStorage->CopyTo( pOtherStorage.get() );
+        SetError( pStorage->GetError() );
+        if( pOtherStorage->GetError() )
+            pDest->SetError( pOtherStorage->GetError() );
+        else
+            pOtherStorage->Commit();
+
+        if ( bDeleteStorage )
+            delete pStorage;
+    }
+
+    return Good() && pDest->Good();
+}
+
+UCBStorageElement_Impl* UCBStorage::FindElement_Impl( std::u16string_view rName ) const
+{
+    DBG_ASSERT( !rName.empty(), "Name is empty!" );
+    for (const auto& pElement : pImp->GetChildrenList())
+    {
+        if ( pElement->m_aName == rName && !pElement->m_bIsRemoved )
+            return pElement.get();
+    }
+    return nullptr;
+}
+
+bool UCBStorage::CopyTo( BaseStorage* pDestStg ) const
+{
+    DBG_ASSERT( pDestStg != static_cast<BaseStorage const *>(this), "Self-Copying is not possible!" );
+    if ( pDestStg == static_cast<BaseStorage const *>(this) )
+        return false;
+
+    // perhaps it's also a problem if one storage is a parent of the other ?!
+    // or if not: could be optimized ?!
+
+    // For UCB storages, the class id and the format id may differ,
+    // do passing the class id is not sufficient.
+    if( dynamic_cast<const UCBStorage *>(pDestStg) != nullptr )
+        pDestStg->SetClass( pImp->m_aClassId, pImp->m_nFormat,
+                            pImp->m_aUserTypeName );
+    else
+        pDestStg->SetClassId( GetClassId() );
+    pDestStg->SetDirty();
+
+    bool bRet = true;
+    for ( size_t i = 0; i < pImp->GetChildrenList().size() && bRet; ++i )
+    {
+        auto& pElement = pImp->GetChildrenList()[ i ];
+        if ( !pElement->m_bIsRemoved )
+            bRet = CopyStorageElement_Impl( *pElement, pDestStg, pElement->m_aName );
+    }
+
+    if( !bRet )
+        SetError( pDestStg->GetError() );
+    return Good() && pDestStg->Good();
+}
+
+bool UCBStorage::CopyTo( const OUString& rElemName, BaseStorage* pDest, const OUString& rNew )
+{
+    if( rElemName.isEmpty() )
+        return false;
+
+    if ( pDest == static_cast<BaseStorage*>(this) )
+    {
+        // can't double an element
+        return false;
+    }
+    else
+    {
+        // for copying no optimization is useful, because in every case the stream data must be copied
+        UCBStorageElement_Impl* pElement = FindElement_Impl( rElemName );
+        if ( pElement )
+            return CopyStorageElement_Impl( *pElement, pDest, rNew );
+        else
+        {
+            SetError( SVSTREAM_FILE_NOT_FOUND );
+            return false;
+        }
+    }
+}
+
+bool UCBStorage::Commit()
+{
+    // mark this storage for sending it on root commit
+    pImp->m_bCommited = true;
+    if ( pImp->m_bIsRoot )
+        // the root storage coordinates committing by sending a Commit command to its content
+        return ( pImp->Commit() != COMMIT_RESULT_FAILURE );
+    else
+        return true;
+}
+
+bool UCBStorage::Revert()
+{
+    pImp->Revert();
+    return true;
+}
+
+BaseStorageStream* UCBStorage::OpenStream( const OUString& rEleName, StreamMode nMode, bool bDirect )
+{
+    if( rEleName.isEmpty() )
+        return nullptr;
+
+    // try to find the storage element
+    UCBStorageElement_Impl *pElement = FindElement_Impl( rEleName );
+    if ( !pElement )
+    {
+        // element does not exist, check if creation is allowed
+        if( nMode & StreamMode::NOCREATE )
+        {
+            SetError( ( nMode & StreamMode::WRITE ) ? SVSTREAM_CANNOT_MAKE : SVSTREAM_FILE_NOT_FOUND );
+            OUString aName = pImp->m_aURL + "/" + rEleName;
+            UCBStorageStream* pStream = new UCBStorageStream( aName, nMode, bDirect, pImp->m_bRepairPackage, pImp->m_xProgressHandler );
+            pStream->SetError( GetError() );
+            pStream->pImp->m_aName = rEleName;
+            return pStream;
+        }
+        else
+        {
+            // create a new UCBStorageElement and insert it into the list
+            pElement = new UCBStorageElement_Impl( rEleName );
+            pElement->m_bIsInserted = true;
+            pImp->m_aChildrenList.emplace_back( pElement );
+        }
+    }
+
+    if ( !pElement->m_bIsFolder )
+    {
+        // check if stream is already created
+        if ( pElement->m_xStream.is() )
+        {
+            // stream has already been created; if it has no external reference, it may be opened another time
+            if ( pElement->m_xStream->m_pAntiImpl )
+            {
+                OSL_FAIL("Stream is already open!" );
+                SetError( SVSTREAM_ACCESS_DENIED );  // ???
+                return nullptr;
+            }
+            else
+            {
+                // check if stream is opened with the same keyword as before
+                // if not, generate a new stream because it could be encrypted vs. decrypted!
+                if ( pElement->m_xStream->m_aKey.isEmpty() )
+                {
+                    pElement->m_xStream->PrepareCachedForReopen( nMode );
+
+                    return new UCBStorageStream( pElement->m_xStream.get() );
+                }
+            }
+        }
+
+        // stream is opened the first time
+        pImp->OpenStream( pElement, nMode, bDirect );
+
+        // if name has been changed before creating the stream: set name!
+        pElement->m_xStream->m_aName = rEleName;
+        return new UCBStorageStream( pElement->m_xStream.get() );
+    }
+
+    return nullptr;
+}
+
+void UCBStorage_Impl::OpenStream( UCBStorageElement_Impl* pElement, StreamMode nMode, bool bDirect )
+{
+    OUString aName = m_aURL + "/" +pElement->m_aOriginalName;
+    pElement->m_xStream = new UCBStorageStream_Impl( aName, nMode, nullptr, bDirect, m_bRepairPackage, m_xProgressHandler );
+}
+
+BaseStorage* UCBStorage::OpenUCBStorage( const OUString& rEleName, StreamMode nMode, bool bDirect )
+{
+    if( rEleName.isEmpty() )
+        return nullptr;
+
+    return OpenStorage_Impl( rEleName, nMode, bDirect, true );
+}
+
+BaseStorage* UCBStorage::OpenOLEStorage( const OUString& rEleName, StreamMode nMode, bool bDirect )
+{
+    if( rEleName.isEmpty() )
+        return nullptr;
+
+    return OpenStorage_Impl( rEleName, nMode, bDirect, false );
+}
+
+BaseStorage* UCBStorage::OpenStorage( const OUString& rEleName, StreamMode nMode, bool bDirect )
+{
+    if( rEleName.isEmpty() )
+        return nullptr;
+
+    return OpenStorage_Impl( rEleName, nMode, bDirect, true );
+}
+
+BaseStorage* UCBStorage::OpenStorage_Impl( const OUString& rEleName, StreamMode nMode, bool bDirect, bool bForceUCBStorage )
+{
+    // try to find the storage element
+    UCBStorageElement_Impl *pElement = FindElement_Impl( rEleName );
+    if ( !pElement )
+    {
+        // element does not exist, check if creation is allowed
+        if( nMode & StreamMode::NOCREATE )
+        {
+            SetError( ( nMode & StreamMode::WRITE ) ? SVSTREAM_CANNOT_MAKE : SVSTREAM_FILE_NOT_FOUND );
+            OUString aName = pImp->m_aURL + "/" + rEleName;  //  ???
+            UCBStorage *pStorage = new UCBStorage( aName, nMode, bDirect, false, pImp->m_bRepairPackage, pImp->m_xProgressHandler );
+            pStorage->pImp->m_bIsRoot = false;
+            pStorage->pImp->m_bListCreated = true; // the storage is pretty new, nothing to read
+            pStorage->SetError( GetError() );
+            return pStorage;
+        }
+
+        // create a new UCBStorageElement and insert it into the list
+        // problem: perhaps an OLEStorage should be created ?!
+        // Because nothing is known about the element that should be created, an external parameter is needed !
+        pElement = new UCBStorageElement_Impl( rEleName );
+        pElement->m_bIsInserted = true;
+        pImp->m_aChildrenList.emplace_back( pElement );
+    }
+
+    if ( !pElement->m_bIsFolder && ( pElement->m_bIsStorage || !bForceUCBStorage ) )
+    {
+        // create OLE storages on a stream ( see ctor of SotStorage )
+        // Such a storage will be created on a UCBStorageStream; it will write into the stream
+        // if it is opened in direct mode or when it is committed. In this case the stream will be
+        // modified and then it MUST be treated as committed.
+        if ( !pElement->m_xStream.is() )
+        {
+            BaseStorageStream* pStr = OpenStream( rEleName, nMode, bDirect );
+            UCBStorageStream* pStream =  dynamic_cast<UCBStorageStream*>( pStr );
+            if ( !pStream )
+            {
+                SetError( ( nMode & StreamMode::WRITE ) ? SVSTREAM_CANNOT_MAKE : SVSTREAM_FILE_NOT_FOUND );
+                return nullptr;
+            }
+
+            pElement->m_xStream = pStream->pImp;
+            delete pStream;
+        }
+
+        pElement->m_xStream->PrepareCachedForReopen( nMode );
+        bool bInited = pElement->m_xStream->Init();
+        if (!bInited)
+        {
+            SetError( ( nMode & StreamMode::WRITE ) ? SVSTREAM_CANNOT_MAKE : SVSTREAM_FILE_NOT_FOUND );
+            return nullptr;
+        }
+
+        pElement->m_bIsStorage = true;
+        return pElement->m_xStream->CreateStorage();  // can only be created in transacted mode
+    }
+    else if ( pElement->m_xStorage.is() )
+    {
+        // storage has already been opened; if it has no external reference, it may be opened another time
+        if ( pElement->m_xStorage->m_pAntiImpl )
+        {
+            OSL_FAIL("Storage is already open!" );
+            SetError( SVSTREAM_ACCESS_DENIED );  // ???
+        }
+        else
+        {
+            bool bIsWritable = bool( pElement->m_xStorage->m_nMode & StreamMode::WRITE );
+            if ( !bIsWritable && ( nMode & StreamMode::WRITE ) )
+            {
+                OUString aName = pImp->m_aURL + "/" + pElement->m_aOriginalName;
+                UCBStorage* pStorage = new UCBStorage( aName, nMode, bDirect, false, pImp->m_bRepairPackage, pImp->m_xProgressHandler );
+                pElement->m_xStorage = pStorage->pImp;
+                return pStorage;
+            }
+            else
+            {
+                return new UCBStorage( pElement->m_xStorage.get() );
+            }
+        }
+    }
+    else if ( !pElement->m_xStream.is() )
+    {
+        // storage is opened the first time
+        bool bIsWritable = bool(pImp->m_nMode & StreamMode::WRITE);
+        if ( pImp->m_bIsLinked && pImp->m_bIsRoot && bIsWritable )
+        {
+            // make sure that the root storage object has been created before substorages will be created
+            INetURLObject aFolderObj( pImp->m_aURL );
+            aFolderObj.removeSegment();
+
+            Content aFolder( aFolderObj.GetMainURL( INetURLObject::DecodeMechanism::NONE ), Reference < XCommandEnvironment >(), comphelper::getProcessComponentContext() );
+            pImp->m_pContent.reset(new Content);
+            bool bRet = ::utl::UCBContentHelper::MakeFolder( aFolder, pImp->m_aName, *pImp->m_pContent );
+            if ( !bRet )
+            {
+                SetError( SVSTREAM_CANNOT_MAKE );
+                return nullptr;
+            }
+        }
+
+        UCBStorage_Impl* pStor = pImp->OpenStorage( pElement, nMode, bDirect );
+        if ( pStor )
+        {
+            if ( pElement->m_bIsInserted )
+                pStor->m_bListCreated = true; // the storage is pretty new, nothing to read
+
+            return new UCBStorage( pStor );
+        }
+    }
+
+    return nullptr;
+}
+
+UCBStorage_Impl* UCBStorage_Impl::OpenStorage( UCBStorageElement_Impl* pElement, StreamMode nMode, bool bDirect )
+{
+    UCBStorage_Impl* pRet = nullptr;
+    OUString aName = m_aURL + "/" + pElement->m_aOriginalName;  //  ???
+
+    pElement->m_bIsStorage = pElement->m_bIsFolder = true;
+
+    if ( m_bIsLinked && !::utl::UCBContentHelper::Exists( aName ) )
+    {
+        Content aNewFolder;
+        bool bRet = ::utl::UCBContentHelper::MakeFolder( *m_pContent, pElement->m_aOriginalName, aNewFolder );
+        if ( bRet )
+            pRet = new UCBStorage_Impl( aNewFolder, aName, nMode, nullptr, bDirect, false, m_bRepairPackage, m_xProgressHandler );
+    }
+    else
+    {
+        pRet = new UCBStorage_Impl( aName, nMode, nullptr, bDirect, false, m_bRepairPackage, m_xProgressHandler );
+    }
+
+    if ( pRet )
+    {
+        pRet->m_bIsLinked = m_bIsLinked;
+        pRet->m_bIsRoot = false;
+
+        // if name has been changed before creating the stream: set name!
+        pRet->m_aName = pElement->m_aOriginalName;
+        pElement->m_xStorage = pRet;
+    }
+
+    if ( pRet )
+        pRet->Init();
+
+    return pRet;
+}
+
+bool UCBStorage::IsStorage( const OUString& rEleName ) const
+{
+    if( rEleName.isEmpty() )
+        return false;
+
+    const UCBStorageElement_Impl *pElement = FindElement_Impl( rEleName );
+    return ( pElement && pElement->m_bIsStorage );
+}
+
+bool UCBStorage::IsStream( const OUString& rEleName ) const
+{
+    if( rEleName.isEmpty() )
+        return false;
+
+    const UCBStorageElement_Impl *pElement = FindElement_Impl( rEleName );
+    return ( pElement && !pElement->m_bIsStorage );
+}
+
+bool UCBStorage::IsContained( const OUString & rEleName ) const
+{
+    if( rEleName.isEmpty() )
+        return false;
+    const UCBStorageElement_Impl *pElement = FindElement_Impl( rEleName );
+    return ( pElement != nullptr );
+}
+
+void UCBStorage::Remove( const OUString& rEleName )
+{
+    if( rEleName.isEmpty() )
+        return;
+
+    UCBStorageElement_Impl *pElement = FindElement_Impl( rEleName );
+    if ( pElement )
+    {
+        pElement->m_bIsRemoved = true;
+    }
+    else
+        SetError( SVSTREAM_FILE_NOT_FOUND );
+}
+
+bool UCBStorage::ValidateFAT()
+{
+    // ???
+    return true;
+}
+
+bool UCBStorage::Validate( bool  bWrite ) const
+{
+    // ???
+    return ( !bWrite || ( pImp->m_nMode & StreamMode::WRITE ) );
+}
+
+bool UCBStorage::ValidateMode( StreamMode m ) const
+{
+    // ???
+    if( m == ( StreamMode::READ | StreamMode::TRUNC ) )  // from stg.cxx
+        return true;
+    // only SHARE_DENYALL allowed
+    // storages open in r/o mode are OK, since only
+    // the commit may fail
+    if( m & StreamMode::SHARE_DENYALL )
+        return true;
+
+    return true;
+}
+
+bool UCBStorage::Equals( const BaseStorage& rStorage ) const
+{
+    // ???
+    return static_cast<BaseStorage const *>(this) == &rStorage;
+}
+
+bool UCBStorage::IsStorageFile( SvStream* pFile )
+{
+    if ( !pFile )
+        return false;
+
+    sal_uInt64 nPos = pFile->Tell();
+    if ( pFile->TellEnd() < 4 )
+        return false;
+
+    pFile->Seek(0);
+    sal_uInt32 nBytes(0);
+    pFile->ReadUInt32( nBytes );
+
+    // search for the magic bytes
+    bool bRet = ( nBytes == 0x04034b50 );
+    if ( !bRet )
+    {
+        // disk spanned file have an additional header in front of the usual one
+        bRet = ( nBytes == 0x08074b50 );
+        if ( bRet )
+        {
+            nBytes = 0;
+            pFile->ReadUInt32( nBytes );
+            bRet = ( nBytes == 0x04034b50 );
+        }
+    }
+
+    pFile->Seek( nPos );
+    return bRet;
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */