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office-gobmx/tools/source/zcodec/zcodec.cxx
offtkp e9c50fbbc3 tdf#103954: Z compressed graphic formats support for EMF/WMF 
- Added .emz and .wmz file opening support
- Added a function to check for Z compression that
all z comp. formats can use
- Added 3 unit tests for emf/emz/wmz files
and the example files have been checked with
a different tool (File Viewer 4)
- emf/emz file detection changed from magic byte checking
to extension checking, like wmf/wmz does

Change-Id: I3e433fd23d18482648a51cd04b8f467368e97b62
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/132456
Tested-by: Jenkins
Reviewed-by: Tomaž Vajngerl <quikee@gmail.com>
2022-05-06 04:02:05 +02:00

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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 <sal/config.h>
#include <algorithm>
#include <tools/stream.hxx>
#include <zlib.h>
#include <tools/zcodec.hxx>
#include <tools/long.hxx>
/* gzip flag byte */
// GZ_ASCII_FLAG 0x01 /* bit 0 set: file probably ascii text */
#define GZ_HEAD_CRC 0x02 /* bit 1 set: header CRC present */
#define GZ_EXTRA_FIELD 0x04 /* bit 2 set: extra field present */
#define GZ_ORIG_NAME 0x08 /* bit 3 set: original file name present */
#define GZ_COMMENT 0x10 /* bit 4 set: file comment present */
#define GZ_RESERVED 0xE0 /* bits 5..7: reserved */
constexpr sal_uInt16 GZ_MAGIC_BYTES_LE = 0x8B1F; /* gzip magic bytes, little endian */
ZCodec::ZCodec( size_t nInBufSize, size_t nOutBufSize )
: meState(STATE_INIT)
, mbStatus(false)
, mbFinish(false)
, mnInBufSize(nInBufSize)
, mnInToRead(0)
, mpOStm(nullptr)
, mnOutBufSize(nOutBufSize)
, mnCompressLevel(0)
, mbGzLib(false)
{
mpsC_Stream = new z_stream;
}
ZCodec::~ZCodec()
{
auto pStream = static_cast<z_stream*>(mpsC_Stream);
delete pStream;
}
bool ZCodec::IsZCompressed( SvStream& rIStm )
{
sal_uInt64 nCurPos = rIStm.Tell();
rIStm.Seek( 0 );
sal_uInt16 nFirstTwoBytes = 0;
rIStm.ReadUInt16( nFirstTwoBytes );
rIStm.Seek( nCurPos );
return nFirstTwoBytes == GZ_MAGIC_BYTES_LE;
}
void ZCodec::BeginCompression( int nCompressLevel, bool gzLib )
{
assert(meState == STATE_INIT);
mbStatus = true;
mbFinish = false;
mpOStm = nullptr;
mnInToRead = 0xffffffff;
mpInBuf.reset();
mpOutBuf.reset();
auto pStream = static_cast<z_stream*>(mpsC_Stream);
pStream->total_out = pStream->total_in = 0;
mnCompressLevel = nCompressLevel;
mbGzLib = gzLib;
pStream->zalloc = nullptr;
pStream->zfree = nullptr;
pStream->opaque = nullptr;
pStream->avail_out = pStream->avail_in = 0;
}
tools::Long ZCodec::EndCompression()
{
tools::Long retvalue = 0;
auto pStream = static_cast<z_stream*>(mpsC_Stream);
if (meState != STATE_INIT)
{
if (meState == STATE_COMPRESS)
{
if (mbStatus)
{
do
{
ImplWriteBack();
}
while ( deflate( pStream, Z_FINISH ) != Z_STREAM_END );
ImplWriteBack();
}
retvalue = pStream->total_in;
deflateEnd( pStream );
}
else
{
retvalue = pStream->total_out;
inflateEnd( pStream );
}
mpOutBuf.reset();
mpInBuf.reset();
meState = STATE_INIT;
}
return mbStatus ? retvalue : -1;
}
void ZCodec::Compress( SvStream& rIStm, SvStream& rOStm )
{
assert(meState == STATE_INIT);
mpOStm = &rOStm;
InitCompress();
mpInBuf.reset(new sal_uInt8[ mnInBufSize ]);
auto pStream = static_cast<z_stream*>(mpsC_Stream);
for (;;)
{
pStream->next_in = mpInBuf.get();
pStream->avail_in = rIStm.ReadBytes( mpInBuf.get(), mnInBufSize );
if (pStream->avail_in == 0)
break;
if ( pStream->avail_out == 0 )
ImplWriteBack();
if ( deflate( pStream, Z_NO_FLUSH ) < 0 )
{
mbStatus = false;
break;
}
};
}
tools::Long ZCodec::Decompress( SvStream& rIStm, SvStream& rOStm )
{
int err;
size_t nInToRead;
auto pStream = static_cast<z_stream*>(mpsC_Stream);
tools::Long nOldTotal_Out = pStream->total_out;
assert(meState == STATE_INIT);
mpOStm = &rOStm;
InitDecompress(rIStm);
pStream->avail_out = mnOutBufSize;
mpOutBuf.reset(new sal_uInt8[ pStream->avail_out ]);
pStream->next_out = mpOutBuf.get();
do
{
if ( pStream->avail_out == 0 ) ImplWriteBack();
if ( pStream->avail_in == 0 && mnInToRead )
{
nInToRead = std::min( mnInBufSize, mnInToRead );
pStream->next_in = mpInBuf.get();
pStream->avail_in = rIStm.ReadBytes(mpInBuf.get(), nInToRead);
mnInToRead -= nInToRead;
}
err = mbStatus ? inflate(pStream, Z_NO_FLUSH) : Z_ERRNO;
if (err < 0 || err == Z_NEED_DICT)
{
mbStatus = false;
break;
}
}
while ( ( err != Z_STREAM_END) && ( pStream->avail_in || mnInToRead ) );
ImplWriteBack();
return mbStatus ? static_cast<tools::Long>(pStream->total_out - nOldTotal_Out) : -1;
}
void ZCodec::Write( SvStream& rOStm, const sal_uInt8* pData, sal_uInt32 nSize )
{
if (meState == STATE_INIT)
{
mpOStm = &rOStm;
InitCompress();
}
assert(&rOStm == mpOStm);
auto pStream = static_cast<z_stream*>(mpsC_Stream);
pStream->avail_in = nSize;
pStream->next_in = pData;
while ( pStream->avail_in || ( pStream->avail_out == 0 ) )
{
if ( pStream->avail_out == 0 )
ImplWriteBack();
if ( deflate( pStream, Z_NO_FLUSH ) < 0 )
{
mbStatus = false;
break;
}
}
}
tools::Long ZCodec::Read( SvStream& rIStm, sal_uInt8* pData, sal_uInt32 nSize )
{
int err;
size_t nInToRead;
if ( mbFinish )
return 0; // pStream->total_out;
if (meState == STATE_INIT)
{
InitDecompress(rIStm);
}
auto pStream = static_cast<z_stream*>(mpsC_Stream);
pStream->avail_out = nSize;
pStream->next_out = pData;
do
{
if ( pStream->avail_in == 0 && mnInToRead )
{
nInToRead = std::min(mnInBufSize, mnInToRead);
pStream->next_in = mpInBuf.get();
pStream->avail_in = rIStm.ReadBytes(mpInBuf.get(), nInToRead);
mnInToRead -= nInToRead;
}
err = mbStatus ? inflate(pStream, Z_NO_FLUSH) : Z_ERRNO;
if (err < 0 || err == Z_NEED_DICT)
{
// Accept Z_BUF_ERROR as EAGAIN or EWOULDBLOCK.
mbStatus = (err == Z_BUF_ERROR);
break;
}
}
while ( (err != Z_STREAM_END) &&
(pStream->avail_out != 0) &&
(pStream->avail_in || mnInToRead) );
if ( err == Z_STREAM_END )
mbFinish = true;
return (mbStatus ? static_cast<tools::Long>(nSize - pStream->avail_out) : -1);
}
void ZCodec::ImplWriteBack()
{
auto pStream = static_cast<z_stream*>(mpsC_Stream);
size_t nAvail = mnOutBufSize - pStream->avail_out;
if ( nAvail > 0 )
{
pStream->next_out = mpOutBuf.get();
mpOStm->WriteBytes( mpOutBuf.get(), nAvail );
pStream->avail_out = mnOutBufSize;
}
}
void ZCodec::InitCompress()
{
assert(meState == STATE_INIT);
meState = STATE_COMPRESS;
auto pStream = static_cast<z_stream*>(mpsC_Stream);
mbStatus = deflateInit2_(
pStream, mnCompressLevel, Z_DEFLATED, MAX_WBITS, MAX_MEM_LEVEL,
Z_DEFAULT_STRATEGY, ZLIB_VERSION, sizeof (z_stream)) >= 0;
mpOutBuf.reset(new sal_uInt8[mnOutBufSize]);
pStream->next_out = mpOutBuf.get();
pStream->avail_out = mnOutBufSize;
}
void ZCodec::InitDecompress(SvStream & inStream)
{
assert(meState == STATE_INIT);
auto pStream = static_cast<z_stream*>(mpsC_Stream);
if ( mbStatus && mbGzLib )
{
sal_uInt8 j, nMethod, nFlags;
sal_uInt16 nFirstTwoBytes;
inStream.Seek( 0 );
inStream.ReadUInt16( nFirstTwoBytes );
if ( nFirstTwoBytes != GZ_MAGIC_BYTES_LE )
mbStatus = false;
inStream.ReadUChar( nMethod );
inStream.ReadUChar( nFlags );
if ( nMethod != Z_DEFLATED )
mbStatus = false;
if ( ( nFlags & GZ_RESERVED ) != 0 )
mbStatus = false;
/* Discard time, xflags and OS code: */
inStream.SeekRel( 6 );
/* skip the extra field */
if ( nFlags & GZ_EXTRA_FIELD )
{
sal_uInt8 n1, n2;
inStream.ReadUChar( n1 ).ReadUChar( n2 );
inStream.SeekRel( n1 + ( n2 << 8 ) );
}
/* skip the original file name */
if ( nFlags & GZ_ORIG_NAME)
{
do
{
inStream.ReadUChar( j );
}
while ( j && !inStream.eof() );
}
/* skip the .gz file comment */
if ( nFlags & GZ_COMMENT )
{
do
{
inStream.ReadUChar( j );
}
while ( j && !inStream.eof() );
}
/* skip the header crc */
if ( nFlags & GZ_HEAD_CRC )
inStream.SeekRel( 2 );
if ( mbStatus )
mbStatus = inflateInit2( pStream, -MAX_WBITS) == Z_OK;
}
else
{
mbStatus = ( inflateInit( pStream ) >= 0 );
}
if ( mbStatus )
meState = STATE_DECOMPRESS;
mpInBuf.reset(new sal_uInt8[ mnInBufSize ]);
}
bool ZCodec::AttemptDecompression(SvStream& rIStm, SvStream& rOStm)
{
assert(meState == STATE_INIT);
sal_uInt64 nStreamPos = rIStm.Tell();
BeginCompression(ZCODEC_DEFAULT_COMPRESSION, true/*gzLib*/);
InitDecompress(rIStm);
EndCompression();
if ( !mbStatus || rIStm.GetError() )
{
rIStm.Seek(nStreamPos);
return false;
}
rIStm.Seek(nStreamPos);
BeginCompression(ZCODEC_DEFAULT_COMPRESSION, true/*gzLib*/);
Decompress(rIStm, rOStm);
EndCompression();
if( !mbStatus || rIStm.GetError() || rOStm.GetError() )
{
rIStm.Seek(nStreamPos);
return false;
}
rIStm.Seek(nStreamPos);
rOStm.Seek(0);
return true;
}
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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