office-gobmx/oox/source/ole/vbainputstream.cxx
Noel Power e3ef9bebf6 tweak compressession hack to fix vba module import
it seems that the heuristic to trigger the inflate hack from frob is both wrong in the code ( my fault ) and additionally doesn't always hold true ( found a document where the heuristic is triggered falsely ) So. removing that heuristic entirely for now
2011-10-21 11:07:38 +01:00

225 lines
7.9 KiB
C++

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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#include "oox/ole/vbainputstream.hxx"
#include <osl/diagnose.h>
namespace oox {
namespace 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 = 0;
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 = reinterpret_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 ) commpessed 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.resize( maChunk.size() + 1 );
*mpInStrm >> maChunk.back();
++nChunkPos;
}
}
}
}
else
{
maChunk.resize( nChunkLen );
mpInStrm->readMemory( &maChunk.front(), 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 boundry
mpInStrm->seek( target );
mnChunkPos = 0;
return !mbEof;
}
// ============================================================================
} // namespace ole
} // namespace oox
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