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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 :
27 :
28 : namespace {
29 :
30 : const sal_uInt8 VBASTREAM_SIGNATURE = 1;
31 :
32 : const sal_uInt16 VBACHUNK_SIGMASK = 0x7000;
33 : const sal_uInt16 VBACHUNK_SIG = 0x3000;
34 : const sal_uInt16 VBACHUNK_COMPRESSED = 0x8000;
35 : const sal_uInt16 VBACHUNK_LENMASK = 0x0FFF;
36 :
37 : } // namespace
38 :
39 :
40 :
41 0 : VbaInputStream::VbaInputStream( BinaryInputStream& rInStrm ) :
42 : BinaryStreamBase( false ),
43 : mpInStrm( &rInStrm ),
44 0 : mnChunkPos( 0 )
45 : {
46 0 : maChunk.reserve( 4096 );
47 :
48 0 : sal_uInt8 nSig = rInStrm.readuInt8();
49 : OSL_ENSURE( nSig == VBASTREAM_SIGNATURE, "VbaInputStream::VbaInputStream - wrong signature" );
50 0 : mbEof = mbEof || rInStrm.isEof() || (nSig != VBASTREAM_SIGNATURE);
51 0 : }
52 :
53 0 : sal_Int64 VbaInputStream::size() const
54 : {
55 0 : return -1;
56 : }
57 :
58 0 : sal_Int64 VbaInputStream::tell() const
59 : {
60 0 : return -1;
61 : }
62 :
63 0 : void VbaInputStream::seek( sal_Int64 )
64 : {
65 0 : }
66 :
67 0 : void VbaInputStream::close()
68 : {
69 0 : mpInStrm = 0;
70 0 : mbEof = true;
71 0 : }
72 :
73 0 : sal_Int32 VbaInputStream::readData( StreamDataSequence& orData, sal_Int32 nBytes, size_t nAtomSize )
74 : {
75 0 : sal_Int32 nRet = 0;
76 0 : if( !mbEof )
77 : {
78 0 : orData.realloc( ::std::max< sal_Int32 >( nBytes, 0 ) );
79 0 : if( nBytes > 0 )
80 : {
81 0 : nRet = readMemory( orData.getArray(), nBytes, nAtomSize );
82 0 : if( nRet < nBytes )
83 0 : orData.realloc( nRet );
84 : }
85 : }
86 0 : return nRet;
87 : }
88 :
89 0 : sal_Int32 VbaInputStream::readMemory( void* opMem, sal_Int32 nBytes, size_t /*nAtomSize*/ )
90 : {
91 0 : sal_Int32 nRet = 0;
92 0 : sal_uInt8* opnMem = reinterpret_cast< sal_uInt8* >( opMem );
93 0 : while( (nBytes > 0) && updateChunk() )
94 : {
95 0 : sal_Int32 nChunkLeft = static_cast< sal_Int32 >( maChunk.size() - mnChunkPos );
96 0 : sal_Int32 nReadBytes = ::std::min( nBytes, nChunkLeft );
97 0 : memcpy( opnMem, &*(maChunk.begin() + mnChunkPos), nReadBytes );
98 0 : opnMem += nReadBytes;
99 0 : mnChunkPos += static_cast< size_t >( nReadBytes );
100 0 : nBytes -= nReadBytes;
101 0 : nRet += nReadBytes;
102 : }
103 0 : return nRet;
104 : }
105 :
106 0 : void VbaInputStream::skip( sal_Int32 nBytes, size_t /*nAtomSize*/ )
107 : {
108 0 : while( (nBytes > 0) && updateChunk() )
109 : {
110 0 : sal_Int32 nChunkLeft = static_cast< sal_Int32 >( maChunk.size() - mnChunkPos );
111 0 : sal_Int32 nSkipBytes = ::std::min( nBytes, nChunkLeft );
112 0 : mnChunkPos += static_cast< size_t >( nSkipBytes );
113 0 : nBytes -= nSkipBytes;
114 : }
115 0 : }
116 :
117 : // private --------------------------------------------------------------------
118 :
119 0 : bool VbaInputStream::updateChunk()
120 : {
121 0 : if( mbEof || (mnChunkPos < maChunk.size()) ) return !mbEof;
122 : // try to read next chunk header, this may trigger EOF
123 0 : sal_uInt16 nHeader = mpInStrm->readuInt16();
124 :
125 0 : mbEof = mpInStrm->isEof();
126 0 : if( mbEof ) return false;
127 :
128 : // check header signature
129 0 : bool bIgnoreBrokenSig = !( (nHeader & VBACHUNK_SIGMASK) == VBACHUNK_SIG );
130 :
131 : // decode length of chunk data and compression flag
132 0 : bool bCompressed = getFlag( nHeader, VBACHUNK_COMPRESSED );
133 0 : sal_uInt16 nChunkLen = (nHeader & VBACHUNK_LENMASK) + 1;
134 : OSL_ENSURE( bCompressed || (nChunkLen == 4096), "VbaInputStream::updateChunk - invalid uncompressed chunk size" );
135 :
136 : // From the amazing bit detective work of Valek Filippov<frob@gnome.org>
137 : // this tweak and the one at the bottom of the method to seek to the
138 : // start of the next chunk we can read those strange broken
139 : // ( I guess from a MSO bug ) commpessed streams > 4k
140 :
141 0 : if ( bIgnoreBrokenSig )
142 : {
143 0 : bCompressed = true;
144 0 : nChunkLen = 4094;
145 : }
146 :
147 0 : sal_Int64 target = mpInStrm->tell() + nChunkLen;
148 0 : if( bCompressed )
149 : {
150 0 : maChunk.clear();
151 0 : sal_uInt8 nBitCount = 4;
152 0 : sal_uInt16 nChunkPos = 0;
153 0 : while( !mbEof && !mpInStrm->isEof() && (nChunkPos < nChunkLen) )
154 : {
155 0 : sal_uInt8 nTokenFlags = mpInStrm->readuInt8();
156 0 : ++nChunkPos;
157 0 : for( int nBit = 0; !mbEof && !mpInStrm->isEof() && (nBit < 8) && (nChunkPos < nChunkLen); ++nBit, nTokenFlags >>= 1 )
158 : {
159 0 : if( nTokenFlags & 1 )
160 : {
161 0 : sal_uInt16 nCopyToken = mpInStrm->readuInt16();
162 0 : nChunkPos = nChunkPos + 2;
163 : // update bit count used for offset/length in the token
164 0 : while( static_cast< size_t >( 1 << nBitCount ) < maChunk.size() ) ++nBitCount;
165 : // extract length from lower (16-nBitCount) bits, plus 3
166 0 : sal_uInt16 nLength = extractValue< sal_uInt16 >( nCopyToken, 0, 16 - nBitCount ) + 3;
167 : // extract offset from high nBitCount bits, plus 1
168 0 : sal_uInt16 nOffset = extractValue< sal_uInt16 >( nCopyToken, 16 - nBitCount, nBitCount ) + 1;
169 0 : mbEof = (nOffset > maChunk.size()) || (maChunk.size() + nLength > 4096);
170 : OSL_ENSURE( !mbEof, "VbaInputStream::updateChunk - invalid offset or size in copy token" );
171 0 : if( !mbEof )
172 : {
173 : // append data to buffer
174 0 : maChunk.resize( maChunk.size() + nLength );
175 0 : sal_uInt8* pnTo = &*(maChunk.end() - nLength);
176 0 : const sal_uInt8* pnEnd = pnTo + nLength;
177 0 : const sal_uInt8* pnFrom = pnTo - nOffset;
178 : // offset may be less than length, effectively duplicating source data several times
179 0 : size_t nRunLen = ::std::min< size_t >( nLength, nOffset );
180 0 : while( pnTo < pnEnd )
181 : {
182 0 : size_t nStepLen = ::std::min< size_t >( nRunLen, pnEnd - pnTo );
183 0 : memcpy( pnTo, pnFrom, nStepLen );
184 0 : pnTo += nStepLen;
185 : }
186 : }
187 : }
188 : // we suspect this will never be called
189 : else
190 : {
191 0 : maChunk.resize( maChunk.size() + 1 );
192 0 : *mpInStrm >> maChunk.back();
193 0 : ++nChunkPos;
194 : }
195 : }
196 : }
197 : }
198 : else
199 : {
200 0 : maChunk.resize( nChunkLen );
201 0 : mpInStrm->readMemory( &maChunk.front(), nChunkLen );
202 : }
203 : // decompression sometimes leaves the stream pos offset 1 place ( at
204 : // least ) past or before the expected stream pos.
205 : // here we make sure we are on the chunk boundry
206 0 : mpInStrm->seek( target );
207 0 : mnChunkPos = 0;
208 0 : return !mbEof;
209 : }
210 :
211 :
212 :
213 : } // namespace ole
214 : } // namespace oox
215 :
216 : /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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