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/*
* Copyright (C) 2007-2012 Xagasoft, All rights reserved.
*
* This file is part of the libbu++ library and is released under the
* terms of the license contained in the file LICENSE.
*/
#ifndef BU_CIPHER_H
#define BU_CIPHER_H
#include "bu/filter.h"
#include "bu/util.h"
namespace Bu
{
template<int iBlockSize>
class Cipher : public Bu::Filter
{
public:
Cipher( Bu::Stream &rNext ) :
Bu::Filter( rNext ),
iReadBufFill( 0 ),
iReadBufPos( 0 ),
iWriteBufFill( 0 )
{
}
virtual ~Cipher()
{
}
virtual void start()
{
}
virtual Bu::size stop()
{
return 0;
}
virtual Bu::size read( void *pBuf, Bu::size iBytes )
{
Bu::size iRead = 0;
while( iRead < iBytes )
{
if( iReadBufFill < iBlockSize )
{
int iR = rNext.read(
aReadBuf+iReadBufFill,
iBlockSize-iReadBufFill
);
if( iR == 0 )
return iRead;
iReadBufFill += iR;
if( iReadBufFill == iBlockSize )
decipher( aReadBuf );
}
if( iReadBufFill == iBlockSize )
{
int iCpy = Bu::min( (int)(iBytes-iRead), iBlockSize-iReadBufPos );
memcpy( ((char *)pBuf)+iRead, aReadBuf+iReadBufPos, iCpy );
iRead += iCpy;
iReadBufPos += iCpy;
if( iReadBufPos == iBlockSize )
{
iReadBufPos = iReadBufFill = 0;
}
}
}
return iRead;
}
virtual Bu::size write( const void *pBuf, Bu::size iBytes )
{
Bu::size iPos = 0;
while( iPos < iBytes )
{
int iLeft = Bu::min((int)(iBytes-iPos),iBlockSize-iReadBufFill);
memcpy( aReadBuf+iReadBufFill, (char *)pBuf+iPos, iLeft );
iPos += iLeft;
iReadBufFill += iLeft;
if( iReadBufFill == iBlockSize )
{
encipher( aReadBuf );
rNext.write( aReadBuf, iBlockSize );
iReadBufFill = 0;
}
}
return iPos;
}
using Bu::Stream::read;
using Bu::Stream::write;
protected:
virtual void encipher( void *pData )=0;
virtual void decipher( void *pData )=0;
private:
char aReadBuf[iBlockSize];
char aWriteBuf[iBlockSize];
int iReadBufFill;
int iReadBufPos;
int iWriteBufFill;
};
};
#endif
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