1 files changed, 208 insertions, 0 deletions
diff --git a/oox/source/ole/vbainputstream.cxx b/oox/source/ole/vbainputstream.cxx
new file mode 100644
index 0000000000..fc795d30de
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+++ b/oox/source/ole/vbainputstream.cxx
@@ -0,0 +1,208 @@
+/* -*- 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 <oox/ole/vbainputstream.hxx>
+#include <osl/diagnose.h>
+
+namespace oox::ole {
+
+namespace {
+
+const sal_uInt8 VBASTREAM_SIGNATURE         = 1;
+
+const sal_uInt16 VBACHUNK_SIGMASK           = 0x7000;
+const sal_uInt16 VBACHUNK_SIG               = 0x3000;
+const sal_uInt16 VBACHUNK_COMPRESSED        = 0x8000;
+const sal_uInt16 VBACHUNK_LENMASK           = 0x0FFF;
+
+} // namespace
+
+VbaInputStream::VbaInputStream( BinaryInputStream& rInStrm ) :
+    BinaryStreamBase( false ),
+    mpInStrm( &rInStrm ),
+    mnChunkPos( 0 )
+{
+    maChunk.reserve( 4096 );
+
+    sal_uInt8 nSig = rInStrm.readuInt8();
+    OSL_ENSURE( nSig == VBASTREAM_SIGNATURE, "VbaInputStream::VbaInputStream - wrong signature" );
+    mbEof = mbEof || rInStrm.isEof() || (nSig != VBASTREAM_SIGNATURE);
+}
+
+sal_Int64 VbaInputStream::size() const
+{
+    return -1;
+}
+
+sal_Int64 VbaInputStream::tell() const
+{
+    return -1;
+}
+
+void VbaInputStream::seek( sal_Int64 )
+{
+}
+
+void VbaInputStream::close()
+{
+    mpInStrm = nullptr;
+    mbEof = true;
+}
+
+sal_Int32 VbaInputStream::readData( StreamDataSequence& orData, sal_Int32 nBytes, size_t nAtomSize )
+{
+    sal_Int32 nRet = 0;
+    if( !mbEof )
+    {
+        orData.realloc( ::std::max< sal_Int32 >( nBytes, 0 ) );
+        if( nBytes > 0 )
+        {
+            nRet = readMemory( orData.getArray(), nBytes, nAtomSize );
+            if( nRet < nBytes )
+                orData.realloc( nRet );
+        }
+    }
+    return nRet;
+}
+
+sal_Int32 VbaInputStream::readMemory( void* opMem, sal_Int32 nBytes, size_t /*nAtomSize*/ )
+{
+    sal_Int32 nRet = 0;
+    sal_uInt8* opnMem = static_cast< sal_uInt8* >( opMem );
+    while( (nBytes > 0) && updateChunk() )
+    {
+        sal_Int32 nChunkLeft = static_cast< sal_Int32 >( maChunk.size() - mnChunkPos );
+        sal_Int32 nReadBytes = ::std::min( nBytes, nChunkLeft );
+        memcpy( opnMem, &*(maChunk.begin() + mnChunkPos), nReadBytes );
+        opnMem += nReadBytes;
+        mnChunkPos += static_cast< size_t >( nReadBytes );
+        nBytes -= nReadBytes;
+        nRet += nReadBytes;
+    }
+    return nRet;
+}
+
+void VbaInputStream::skip( sal_Int32 nBytes, size_t /*nAtomSize*/ )
+{
+    while( (nBytes > 0) && updateChunk() )
+    {
+        sal_Int32 nChunkLeft = static_cast< sal_Int32 >( maChunk.size() - mnChunkPos );
+        sal_Int32 nSkipBytes = ::std::min( nBytes, nChunkLeft );
+        mnChunkPos += static_cast< size_t >( nSkipBytes );
+        nBytes -= nSkipBytes;
+    }
+}
+
+// private --------------------------------------------------------------------
+
+bool VbaInputStream::updateChunk()
+{
+    if( mbEof || (mnChunkPos < maChunk.size()) ) return !mbEof;
+    // try to read next chunk header, this may trigger EOF
+    sal_uInt16 nHeader = mpInStrm->readuInt16();
+
+    mbEof = mpInStrm->isEof();
+    if( mbEof ) return false;
+
+    // check header signature
+    bool bIgnoreBrokenSig = ( (nHeader & VBACHUNK_SIGMASK) != VBACHUNK_SIG );
+
+    // decode length of chunk data and compression flag
+    bool bCompressed = getFlag( nHeader, VBACHUNK_COMPRESSED );
+    sal_uInt16 nChunkLen = (nHeader & VBACHUNK_LENMASK) + 1;
+    OSL_ENSURE( bCompressed || (nChunkLen == 4096), "VbaInputStream::updateChunk - invalid uncompressed chunk size" );
+
+    // From the amazing bit detective work of Valek Filippov<frob@gnome.org>
+    // this tweak and the one at the bottom of the method to seek to the
+    // start of the next chunk we can read those strange broken
+    // ( I guess from a MSO bug ) compressed streams > 4k
+
+    if ( bIgnoreBrokenSig )
+    {
+        bCompressed = true;
+        nChunkLen = 4094;
+    }
+
+    sal_Int64 target = mpInStrm->tell() + nChunkLen;
+    if( bCompressed )
+    {
+        maChunk.clear();
+        sal_uInt8 nBitCount = 4;
+        sal_uInt16 nChunkPos = 0;
+        while( !mbEof && !mpInStrm->isEof() && (nChunkPos < nChunkLen) )
+        {
+            sal_uInt8 nTokenFlags = mpInStrm->readuInt8();
+            ++nChunkPos;
+            for( int nBit = 0; !mbEof && !mpInStrm->isEof() && (nBit < 8) && (nChunkPos < nChunkLen); ++nBit, nTokenFlags >>= 1 )
+            {
+                if( nTokenFlags & 1 )
+                {
+                    sal_uInt16 nCopyToken = mpInStrm->readuInt16();
+                    nChunkPos = nChunkPos + 2;
+                    // update bit count used for offset/length in the token
+                    while( ( static_cast<size_t>(1) << nBitCount ) < maChunk.size() ) ++nBitCount;
+                    // extract length from lower (16-nBitCount) bits, plus 3
+                    sal_uInt16 nLength = extractValue< sal_uInt16 >( nCopyToken, 0, 16 - nBitCount ) + 3;
+                    // extract offset from high nBitCount bits, plus 1
+                    sal_uInt16 nOffset = extractValue< sal_uInt16 >( nCopyToken, 16 - nBitCount, nBitCount ) + 1;
+                    mbEof = (nOffset > maChunk.size()) || (maChunk.size() + nLength > 4096);
+                    OSL_ENSURE( !mbEof, "VbaInputStream::updateChunk - invalid offset or size in copy token" );
+                    if( !mbEof )
+                    {
+                        // append data to buffer
+                        maChunk.resize( maChunk.size() + nLength );
+                        sal_uInt8* pnTo = &*(maChunk.end() - nLength);
+                        const sal_uInt8* pnEnd = pnTo + nLength;
+                        const sal_uInt8* pnFrom = pnTo - nOffset;
+                        // offset may be less than length, effectively duplicating source data several times
+                        size_t nRunLen = ::std::min< size_t >( nLength, nOffset );
+                        while( pnTo < pnEnd )
+                        {
+                            size_t nStepLen = ::std::min< size_t >( nRunLen, pnEnd - pnTo );
+                            memcpy( pnTo, pnFrom, nStepLen );
+                            pnTo += nStepLen;
+                        }
+                    }
+                }
+                // we suspect this will never be called
+                else
+                {
+                    maChunk.emplace_back();
+                    maChunk.back() = mpInStrm->readuChar();
+                    ++nChunkPos;
+                }
+            }
+        }
+    }
+    else
+    {
+        maChunk.resize( nChunkLen );
+        mpInStrm->readMemory(maChunk.data(), nChunkLen);
+    }
+    // decompression sometimes leaves the stream pos offset 1 place ( at
+    // least ) past or before the expected stream pos.
+    // here we make sure we are on the chunk boundary
+    mpInStrm->seek( target );
+    mnChunkPos = 0;
+    return !mbEof;
+}
+
+} // namespace oox::ole
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */