Adding upstream version 4:24.2.0.upstream/4%24.2.0

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

1 files changed, 1356 insertions, 0 deletions

diff --git a/sot/source/sdstor/stgstrms.cxx b/sot/source/sdstor/stgstrms.cxx
new file mode 100644
index 0000000000..61682ead8a
--- /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::CreateTempURL();
+            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_uInt64 nCur = Tell();
+    sal_uInt64 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: */