xref: /aoo42x/main/comphelper/inc/comphelper/streamsection.hxx (revision 9877b273)

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 * Licensed to the Apache Software Foundation (ASF) under one
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 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
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#ifndef _COMPHELPER_STREAMSECTION_HXX_
#define _COMPHELPER_STREAMSECTION_HXX_

#include <com/sun/star/io/XMarkableStream.hpp>
#include <com/sun/star/io/XDataInputStream.hpp>
#include <com/sun/star/io/XDataOutputStream.hpp>
#include "comphelper/comphelperdllapi.h"

namespace comphelper
{

	namespace stario	= ::com::sun::star::io;
	namespace staruno	= ::com::sun::star::uno;

/** implements handling for compatibly reading/writing data from/into an input/output stream.
	data written in a block secured by this class should be readable by older versions which
	use the same mechanism.

	@author	Frank Schoenheit
	@since	00/26/05
*/

class COMPHELPER_DLLPUBLIC OStreamSection
{
	staruno::Reference< stario::XMarkableStream >		m_xMarkStream;
	staruno::Reference< stario::XDataInputStream >		m_xInStream;
	staruno::Reference< stario::XDataOutputStream >		m_xOutStream;

	sal_Int32	m_nBlockStart;
	sal_Int32	m_nBlockLen;

public:
	/**	starts reading of a "skippable" section of data within the given input stream<BR>
		@param		_rxInput	the stream to read from. Must support the
								<type scope="com::sun::star::io">XMarkableStream</type> interface
	*/
	OStreamSection(const staruno::Reference< stario::XDataInputStream >& _rxInput);

	/**	starts writing of a "skippable" section of data into the given output stream
		@param		_rxOutput			the stream the stream to write to. Must support the
										<type scope="com::sun::star::io">XMarkableStream</type> interface
		@param		_nPresumedLength	estimation for the length of the upcoming section. If greater 0, this
										value will be written as section length and corrected (in the dtor) only if
										needed. If you know how much bytes you are about to write, you may
										want to use this param, saving some stream operations this way.
	*/
	OStreamSection(const staruno::Reference< stario::XDataOutputStream >& _rxOutput, sal_Int32 _nPresumedLength = 0);

	/** dtor. <BR>If constructed for writing, the section "opened" by this object will be "closed".<BR>
		If constructed for reading, any remaining bytes 'til the end of the section will be skipped.
	*/
	~OStreamSection();
	/**
		return the number of bytes which are still available
	*/
	sal_Int32 available();
};

}	// namespace comphelper

#endif // _COMPHELPER_STREAMSECTION_HXX_