#ifndef FILTER_H
#define FILTER_H

#include <stdint.h>

#include "bu/stream.h"

namespace Bu
{
	/**
	 * Data filter base class.  Each data filter should contain a read and write
	 * section.  Effectively, the write applies the filter, the read un-applies
	 * the filter, if possible.  For example, BZip2 is a filter that compresses
	 * on write and decompresses on read.  All bi-directional filters should
	 * follow:  x == read( write( x ) ) (byte-for-byte comparison)
	 *
	 * Also, all returned buffers should be owned by the filter, and deleted
	 * when the filter is deleted.  This means that the output of a read or
	 * write operation must be used before the next call to read or write or the
	 * data will be destroyed.  Also, the internal buffer may be changed or
	 * recreated between calls, so always get a new pointer from a call to
	 * read or write.
	 *
	 * The close function can also return data, so make sure to check for it,
	 * many filters such as compression filters will buffer data until they have
	 * enough to create a compression block, in these cases the leftover data
	 * will be returned by close.
	 */
	class Filter : public Bu::Stream
	{
	public:
		Filter( Bu::Stream &rNext );
		virtual ~Filter();

		virtual void start()=0;
		virtual size_t stop()=0;
		virtual void close();
		virtual long tell();
		virtual void seek( long offset );
		virtual void setPos( long pos );
		virtual void setPosEnd( long pos );
		virtual bool isEOS();

		virtual void flush();

		virtual bool canRead();
		virtual bool canWrite();
		virtual bool canSeek();

		virtual bool isBlocking();
		virtual void setBlocking( bool bBlocking=true );

	protected:
		Bu::Stream &rNext;

	private:

	};
}

#endif