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/*
* Copyright (C) 2007-2011 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_SUB_STREAM_H
#define BU_SUB_STREAM_H
#include "bu/filter.h"
namespace Bu
{
/**
* Creates a sub-stream of a given stream. This allows you to read and
* write safely to a section of another stream, keeping all data within
* the given bounds. The substream acts exactly like a top level stream
* when you reach the bounds of either the containing stream or the
* artificial bounds of the substream, except that unlike many stream types,
* when writing you cannot move beyond the bounds of the substream. Reads,
* on the other hand, work exactly the same way, returning less data than
* requested when the end of the stream is reached.
*
* The substream always begins at the current position in the base stream,
* if you would like to skip some data first, simply seek.
*
* The substream class is safe to use with all blocking and non-blocking
* base streams, including sockets, however it can have unpredictable
* results when used on a buffering stream that may read more data than
* requested in order to complete a request such as the buffer or bzip2
* filters.
*/
class SubStream : public Bu::Filter
{
public:
SubStream( Bu::Stream &rNext, Bu::size iSize );
virtual ~SubStream();
virtual Bu::size read( void *pBuf, Bu::size nBytes );
virtual Bu::size write( const void *pBuf, Bu::size nBytes );
using Bu::Stream::write;
virtual void start();
virtual Bu::size stop();
virtual void close();
virtual Bu::size tell();
virtual void seek( Bu::size offset );
virtual void setPos( Bu::size pos );
virtual void setPosEnd( Bu::size pos );
virtual bool isEos();
virtual bool canRead();
virtual bool canWrite();
protected:
Bu::size iStart;
Bu::size iPos;
Bu::size iSize;
};
};
#endif
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