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1 : /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
2 : /*
3 : * This file is part of the LibreOffice project.
4 : *
5 : * This Source Code Form is subject to the terms of the Mozilla Public
6 : * License, v. 2.0. If a copy of the MPL was not distributed with this
7 : * file, You can obtain one at http://mozilla.org/MPL/2.0/.
8 : *
9 : * This file incorporates work covered by the following license notice:
10 : *
11 : * Licensed to the Apache Software Foundation (ASF) under one or more
12 : * contributor license agreements. See the NOTICE file distributed
13 : * with this work for additional information regarding copyright
14 : * ownership. The ASF licenses this file to you under the Apache
15 : * License, Version 2.0 (the "License"); you may not use this file
16 : * except in compliance with the License. You may obtain a copy of
17 : * the License at http://www.apache.org/licenses/LICENSE-2.0 .
18 : */
19 :
20 : #include "oox/ole/vbainputstream.hxx"
21 : #include <osl/diagnose.h>
22 :
23 : namespace oox {
24 : namespace ole {
25 :
26 : namespace {
27 :
28 : const sal_uInt8 VBASTREAM_SIGNATURE = 1;
29 :
30 : const sal_uInt16 VBACHUNK_SIGMASK = 0x7000;
31 : const sal_uInt16 VBACHUNK_SIG = 0x3000;
32 : const sal_uInt16 VBACHUNK_COMPRESSED = 0x8000;
33 : const sal_uInt16 VBACHUNK_LENMASK = 0x0FFF;
34 :
35 : } // namespace
36 :
37 364 : VbaInputStream::VbaInputStream( BinaryInputStream& rInStrm ) :
38 : BinaryStreamBase( false ),
39 : mpInStrm( &rInStrm ),
40 364 : mnChunkPos( 0 )
41 : {
42 364 : maChunk.reserve( 4096 );
43 :
44 364 : sal_uInt8 nSig = rInStrm.readuInt8();
45 : OSL_ENSURE( nSig == VBASTREAM_SIGNATURE, "VbaInputStream::VbaInputStream - wrong signature" );
46 364 : mbEof = mbEof || rInStrm.isEof() || (nSig != VBASTREAM_SIGNATURE);
47 364 : }
48 :
49 0 : sal_Int64 VbaInputStream::size() const
50 : {
51 0 : return -1;
52 : }
53 :
54 0 : sal_Int64 VbaInputStream::tell() const
55 : {
56 0 : return -1;
57 : }
58 :
59 0 : void VbaInputStream::seek( sal_Int64 )
60 : {
61 0 : }
62 :
63 0 : void VbaInputStream::close()
64 : {
65 0 : mpInStrm = 0;
66 0 : mbEof = true;
67 0 : }
68 :
69 7216 : sal_Int32 VbaInputStream::readData( StreamDataSequence& orData, sal_Int32 nBytes, size_t nAtomSize )
70 : {
71 7216 : sal_Int32 nRet = 0;
72 7216 : if( !mbEof )
73 : {
74 7216 : orData.realloc( ::std::max< sal_Int32 >( nBytes, 0 ) );
75 7216 : if( nBytes > 0 )
76 : {
77 5580 : nRet = readMemory( orData.getArray(), nBytes, nAtomSize );
78 5580 : if( nRet < nBytes )
79 304 : orData.realloc( nRet );
80 : }
81 : }
82 7216 : return nRet;
83 : }
84 :
85 15676 : sal_Int32 VbaInputStream::readMemory( void* opMem, sal_Int32 nBytes, size_t /*nAtomSize*/ )
86 : {
87 15676 : sal_Int32 nRet = 0;
88 15676 : sal_uInt8* opnMem = reinterpret_cast< sal_uInt8* >( opMem );
89 47028 : while( (nBytes > 0) && updateChunk() )
90 : {
91 15676 : sal_Int32 nChunkLeft = static_cast< sal_Int32 >( maChunk.size() - mnChunkPos );
92 15676 : sal_Int32 nReadBytes = ::std::min( nBytes, nChunkLeft );
93 15676 : memcpy( opnMem, &*(maChunk.begin() + mnChunkPos), nReadBytes );
94 15676 : opnMem += nReadBytes;
95 15676 : mnChunkPos += static_cast< size_t >( nReadBytes );
96 15676 : nBytes -= nReadBytes;
97 15676 : nRet += nReadBytes;
98 : }
99 15676 : return nRet;
100 : }
101 :
102 0 : void VbaInputStream::skip( sal_Int32 nBytes, size_t /*nAtomSize*/ )
103 : {
104 0 : while( (nBytes > 0) && updateChunk() )
105 : {
106 0 : sal_Int32 nChunkLeft = static_cast< sal_Int32 >( maChunk.size() - mnChunkPos );
107 0 : sal_Int32 nSkipBytes = ::std::min( nBytes, nChunkLeft );
108 0 : mnChunkPos += static_cast< size_t >( nSkipBytes );
109 0 : nBytes -= nSkipBytes;
110 : }
111 0 : }
112 :
113 : // private --------------------------------------------------------------------
114 :
115 15980 : bool VbaInputStream::updateChunk()
116 : {
117 15980 : if( mbEof || (mnChunkPos < maChunk.size()) ) return !mbEof;
118 : // try to read next chunk header, this may trigger EOF
119 744 : sal_uInt16 nHeader = mpInStrm->readuInt16();
120 :
121 744 : mbEof = mpInStrm->isEof();
122 744 : if( mbEof ) return false;
123 :
124 : // check header signature
125 440 : bool bIgnoreBrokenSig = !( (nHeader & VBACHUNK_SIGMASK) == VBACHUNK_SIG );
126 :
127 : // decode length of chunk data and compression flag
128 440 : bool bCompressed = getFlag( nHeader, VBACHUNK_COMPRESSED );
129 440 : sal_uInt16 nChunkLen = (nHeader & VBACHUNK_LENMASK) + 1;
130 : OSL_ENSURE( bCompressed || (nChunkLen == 4096), "VbaInputStream::updateChunk - invalid uncompressed chunk size" );
131 :
132 : // From the amazing bit detective work of Valek Filippov<frob@gnome.org>
133 : // this tweak and the one at the bottom of the method to seek to the
134 : // start of the next chunk we can read those strange broken
135 : // ( I guess from a MSO bug ) commpessed streams > 4k
136 :
137 440 : if ( bIgnoreBrokenSig )
138 : {
139 0 : bCompressed = true;
140 0 : nChunkLen = 4094;
141 : }
142 :
143 440 : sal_Int64 target = mpInStrm->tell() + nChunkLen;
144 440 : if( bCompressed )
145 : {
146 440 : maChunk.clear();
147 440 : sal_uInt8 nBitCount = 4;
148 440 : sal_uInt16 nChunkPos = 0;
149 22162 : while( !mbEof && !mpInStrm->isEof() && (nChunkPos < nChunkLen) )
150 : {
151 21282 : sal_uInt8 nTokenFlags = mpInStrm->readuInt8();
152 21282 : ++nChunkPos;
153 189668 : for( int nBit = 0; !mbEof && !mpInStrm->isEof() && (nBit < 8) && (nChunkPos < nChunkLen); ++nBit, nTokenFlags >>= 1 )
154 : {
155 168386 : if( nTokenFlags & 1 )
156 : {
157 50062 : sal_uInt16 nCopyToken = mpInStrm->readuInt16();
158 50062 : nChunkPos = nChunkPos + 2;
159 : // update bit count used for offset/length in the token
160 50062 : while( static_cast< size_t >( 1 << nBitCount ) < maChunk.size() ) ++nBitCount;
161 : // extract length from lower (16-nBitCount) bits, plus 3
162 50062 : sal_uInt16 nLength = extractValue< sal_uInt16 >( nCopyToken, 0, 16 - nBitCount ) + 3;
163 : // extract offset from high nBitCount bits, plus 1
164 50062 : sal_uInt16 nOffset = extractValue< sal_uInt16 >( nCopyToken, 16 - nBitCount, nBitCount ) + 1;
165 50062 : mbEof = (nOffset > maChunk.size()) || (maChunk.size() + nLength > 4096);
166 : OSL_ENSURE( !mbEof, "VbaInputStream::updateChunk - invalid offset or size in copy token" );
167 50062 : if( !mbEof )
168 : {
169 : // append data to buffer
170 50062 : maChunk.resize( maChunk.size() + nLength );
171 50062 : sal_uInt8* pnTo = &*(maChunk.end() - nLength);
172 50062 : const sal_uInt8* pnEnd = pnTo + nLength;
173 50062 : const sal_uInt8* pnFrom = pnTo - nOffset;
174 : // offset may be less than length, effectively duplicating source data several times
175 50062 : size_t nRunLen = ::std::min< size_t >( nLength, nOffset );
176 152738 : while( pnTo < pnEnd )
177 : {
178 52614 : size_t nStepLen = ::std::min< size_t >( nRunLen, pnEnd - pnTo );
179 52614 : memcpy( pnTo, pnFrom, nStepLen );
180 52614 : pnTo += nStepLen;
181 : }
182 : }
183 : }
184 : // we suspect this will never be called
185 : else
186 : {
187 118324 : maChunk.resize( maChunk.size() + 1 );
188 118324 : *mpInStrm >> maChunk.back();
189 118324 : ++nChunkPos;
190 : }
191 : }
192 : }
193 : }
194 : else
195 : {
196 0 : maChunk.resize( nChunkLen );
197 0 : mpInStrm->readMemory( &maChunk.front(), nChunkLen );
198 : }
199 : // decompression sometimes leaves the stream pos offset 1 place ( at
200 : // least ) past or before the expected stream pos.
201 : // here we make sure we are on the chunk boundry
202 440 : mpInStrm->seek( target );
203 440 : mnChunkPos = 0;
204 440 : return !mbEof;
205 : }
206 :
207 : } // namespace ole
208 : } // namespace oox
209 :
210 : /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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