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/* This file is (c) 2008-2010 Konstantin Isakov <ikm@users.berlios.de>
* Part of GoldenDict. Licensed under GPLv3 or later, see the LICENSE file */
#include "zipfile.hh"
#include <QtEndian>
#include <QByteArray>
namespace ZipFile {
/// End-of-central-directory record, as is
struct EndOfCdirRecord
{
quint32 signature;
quint16 numDisk, numDiskCd, totalEntriesDisk, totalEntries;
quint32 size, offset;
quint16 commentLength;
} __attribute__((packed));
struct CentralFileHeaderRecord
{
quint32 signature;
quint16 verMadeBy, verNeeded, gpBits, compressionMethod, fileTime, fileDate;
quint32 crc32, compressedSize, uncompressedSize;
quint16 fileNameLength, extraFieldLength, fileCommentLength, diskNumberStart,
intFileAttrs;
quint32 externalFileAttrs, offsetOfLocalHeader;
} __attribute__((packed));
struct LocalFileHeaderRecord
{
quint32 signature;
quint16 verNeeded, gpBits, compressionMethod, fileTime, fileDate;
quint32 crc32, compressedSize, uncompressedSize;
quint16 fileNameLength, extraFieldLength;
} __attribute__((packed));
static quint32 const endOfCdirRecordSignatureValue = qToLittleEndian( 0x06054b50 );
static quint32 const centralFileHeaderSignature = qToLittleEndian( 0x02014b50 );
static quint32 const localFileHeaderSignature = qToLittleEndian( 0x04034b50 );
static CompressionMethod getCompressionMethod( quint16 compressionMethod )
{
switch( qFromLittleEndian( compressionMethod ) )
{
case 0:
return Uncompressed;
case 8:
return Deflated;
default:
return Unsupported;
}
}
bool positionAtCentralDir( QFile & zip )
{
// Find the end-of-central-directory record
int maxEofBufferSize = 65535 + sizeof( EndOfCdirRecord );
if ( zip.size() > maxEofBufferSize )
zip.seek( zip.size() - maxEofBufferSize );
else
if ( zip.size() < sizeof( EndOfCdirRecord ) )
return false;
else
zip.seek( 0 );
QByteArray eocBuffer = zip.read( maxEofBufferSize );
if ( eocBuffer.size() < (int)sizeof( EndOfCdirRecord ) )
return false;
int lastIndex = eocBuffer.size() - sizeof( EndOfCdirRecord );
QByteArray endOfCdirRecordSignature( (char const *)&endOfCdirRecordSignatureValue,
sizeof( endOfCdirRecordSignatureValue ) );
EndOfCdirRecord endOfCdirRecord;
for( ; ; --lastIndex )
{
lastIndex = eocBuffer.lastIndexOf( endOfCdirRecordSignature, lastIndex );
if ( lastIndex == -1 )
return false;
/// We need to copy it due to possible alignment issues on ARM etc
memcpy( &endOfCdirRecord, eocBuffer.data() + lastIndex,
sizeof( endOfCdirRecord ) );
/// Sanitize the record by checking the offset
if ( !zip.seek( qFromLittleEndian( endOfCdirRecord.offset ) ) )
continue;
quint32 signature;
if ( zip.read( (char *)&signature, sizeof( signature ) ) != sizeof( signature ) )
continue;
if ( signature == centralFileHeaderSignature )
break;
}
// Found cdir -- position the file on the first header
return zip.seek( qFromLittleEndian( endOfCdirRecord.offset ) );
}
bool readNextEntry( QFile & zip, CentralDirEntry & entry )
{
CentralFileHeaderRecord record;
if ( zip.read( (char *)&record, sizeof( record ) ) != sizeof( record ) )
return false;
if ( record.signature != centralFileHeaderSignature )
return false;
// Read file name
int fileNameLength = qFromLittleEndian( record.fileNameLength );
entry.fileName = zip.read( fileNameLength );
if ( entry.fileName.size() != fileNameLength )
return false;
// Skip extra fields
if ( !zip.seek( ( zip.pos() + qFromLittleEndian( record.extraFieldLength ) ) +
qFromLittleEndian( record.fileCommentLength ) ) )
return false;
entry.localHeaderOffset = qFromLittleEndian( record.offsetOfLocalHeader );
entry.compressedSize = qFromLittleEndian( record.compressedSize );
entry.uncompressedSize = qFromLittleEndian( record.uncompressedSize );
entry.compressionMethod = getCompressionMethod( record.compressionMethod );
return true;
}
bool readLocalHeader( QFile & zip, LocalFileHeader & entry )
{
LocalFileHeaderRecord record;
if ( zip.read( (char *)&record, sizeof( record ) ) != sizeof( record ) )
return false;
if ( record.signature != localFileHeaderSignature )
return false;
// Read file name
int fileNameLength = qFromLittleEndian( record.fileNameLength );
entry.fileName = zip.read( fileNameLength );
if ( entry.fileName.size() != fileNameLength )
return false;
// Skip extra field
if ( !zip.seek( zip.pos() + qFromLittleEndian( record.extraFieldLength ) ) )
return false;
entry.compressedSize = qFromLittleEndian( record.compressedSize );
entry.uncompressedSize = qFromLittleEndian( record.uncompressedSize );
entry.compressionMethod = getCompressionMethod( record.compressionMethod );
return true;
}
}
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