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/*
* Copyright (C) 2007-2023 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.
*/
#include "bu/substream.h"
Bu::SubStream::SubStream( Bu::Stream &rNext, Bu::size iSize ) :
Bu::Filter( rNext ),
iStart( 0 ),
iPos( 0 ),
iSize( iSize )
{
iStart = rNext.tell();
}
Bu::SubStream::~SubStream()
{
}
Bu::size Bu::SubStream::read( void *pBuf, Bu::size nBytes )
{
if( (Bu::size)nBytes > iSize-iPos )
nBytes = iSize-iPos;
nBytes = rNext.read( pBuf, nBytes );
iPos += nBytes;
return nBytes;
}
Bu::size Bu::SubStream::write( const void *pBuf, Bu::size nBytes )
{
if( (Bu::size)nBytes > iSize-iPos )
nBytes = iSize-iPos;
nBytes = rNext.write( pBuf, nBytes );
iPos += nBytes;
return nBytes;
}
void Bu::SubStream::start()
{
// doesn't mean anything...
}
Bu::size Bu::SubStream::stop()
{
// doesn't mean anything...
return 0;
}
void Bu::SubStream::close()
{
// don't do anything? maybe...
}
Bu::size Bu::SubStream::tell()
{
return iPos;
}
void Bu::SubStream::seek( Bu::size offset )
{
if( iPos+offset < 0 )
offset = -iPos;
else if( iPos+offset > iSize )
offset = iSize-iPos;
rNext.seek( offset );
iPos += offset;
}
void Bu::SubStream::setPos( Bu::size pos )
{
if( pos < 0 )
pos = 0;
else if( pos > iSize )
pos = iSize;
iPos = pos;
pos += iStart;
rNext.setPos( pos );
}
void Bu::SubStream::setPosEnd( Bu::size pos )
{
if( iSize-pos < 0 )
pos = 0;
else if( iSize-pos > iSize )
pos = iSize;
else
pos = iSize-pos;
iPos = pos;
rNext.setPos( iStart+pos );
}
bool Bu::SubStream::isEos()
{
return rNext.isEos() || iPos == iSize;
}
bool Bu::SubStream::canRead()
{
return rNext.canRead() && (iPos < iSize);
}
bool Bu::SubStream::canWrite()
{
return rNext.canWrite() && (iPos < iSize);
}
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