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/* -*- 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: */
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