xref: /aoo41x/main/udkapi/com/sun/star/io/XInputStream.idl (revision 408a4873)

/**************************************************************
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * 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
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 *
 *************************************************************/


#ifndef __com_sun_star_io_XInputStream_idl__
#define __com_sun_star_io_XInputStream_idl__

#ifndef __com_sun_star_uno_XInterface_idl__
#include <com/sun/star/uno/XInterface.idl>
#endif

#ifndef __com_sun_star_io_NotConnectedException_idl__
#include <com/sun/star/io/NotConnectedException.idl>
#endif

#ifndef __com_sun_star_io_BufferSizeExceededException_idl__
#include <com/sun/star/io/BufferSizeExceededException.idl>
#endif


//=============================================================================

module com {  module sun {  module star {  module io {

//=============================================================================

// DocMerge from xml: interface com::sun::star::io::XInputStream
/** This is the basic interface to read data from a stream.
    <p>
    See the <a href="http://udk.openoffice.org/common/man/concept/streams.html">
    streaming document</a> for further information on chaining and piping streams.
 */
published interface XInputStream: com::sun::star::uno::XInterface
{
	//-------------------------------------------------------------------------

	// DocMerge from xml: method com::sun::star::io::XInputStream::readBytes
	/** reads the specified number of bytes in the given sequence.

		<p>The return value specifies the number of bytes which have been
		put into the sequence. A difference between <var>nBytesToRead</var>
		and the return value indicates that EOF has been reached. This means
		that the method blocks until the specified number of bytes are
		available or the EOF is reached.  </p>
	   @param aData
	         after the call, the byte sequence contains the requested number
			 of bytes (or less as a sign of EOF).

			 <p>
			 C++ only : Note that for unbridged (e.g., in-process)
			 calls, using the same sequence for repetive readBytes()-calls
			 can bear a performance advantage. The callee can put the data
			 directly into the sequence so that no buffer reallocation is
			 necessary.
			 But this holds only when
			 <ol>
			  <li> neither caller nor callee keep a second reference to the same
			       sequence.
			  <li> the sequence is pre-allocated with the requested number of bytes.
			  <li> the same sequence is reused ( simply preallocationg a new
			       sequence for every call bears no advantage ).
			  <li> the call is not bridged (e.g., betweeen different compilers
			       or different processes ).
			 </ol>

			 If the same 'optimized' code runs against an interface in a different process,
			 there is an unnecessary memory allocation/deallocation (the out parameter
			 is of course NOT transported over the connection), but this should
			 be negligible compared to a synchron call.
	     @param nBytesToRead
		the total number of bytes to read
	 */
	long readBytes( [out] sequence<byte> aData,
			 [in] long nBytesToRead )
			raises( com::sun::star::io::NotConnectedException,
					com::sun::star::io::BufferSizeExceededException,
					com::sun::star::io::IOException);

	//-------------------------------------------------------------------------

	// DocMerge from xml: method com::sun::star::io::XInputStream::readSomeBytes
	/** reads the available number of bytes, at maximum
		<var>nMaxBytesToRead</var>.

		<p>This method is very similar to the readBytes method, except that
           it has different blocking behaviour.
           The method blocks as long as at least 1 byte is available or
           EOF has been reached. EOF has only been reached, when the method
           returns 0 and the corresponding byte sequence is empty.
           Otherwise, after the call, aData contains the available,
           but no more than nMaxBytesToRead, bytes.
        @param aData contains the data read from the stream.
        @param nMaxBytesToRead The maximum number of bytes to be read from this
                               stream during the call.
        @see com::sun::star::io::XInputStream::readBytes
	 */
	long readSomeBytes( [out] sequence<byte> aData,
			 [in] long nMaxBytesToRead )
			raises( com::sun::star::io::NotConnectedException,
					com::sun::star::io::BufferSizeExceededException,
					com::sun::star::io::IOException );

	//-------------------------------------------------------------------------

	// DocMerge from xml: method com::sun::star::io::XInputStream::skipBytes
	/** skips the next <var>nBytesToSkip</var> bytes (must be positive).

		<p>It is up to the implementation whether this method is
		blocking the thread or not.  </p>
	  @param nBytesToSkip
		number of bytes to skip
	 */
	void skipBytes( [in] long nBytesToSkip )
			raises( com::sun::star::io::NotConnectedException,
					com::sun::star::io::BufferSizeExceededException,
					com::sun::star::io::IOException );

	//-------------------------------------------------------------------------

	// DocMerge from xml: method com::sun::star::io::XInputStream::available
	/** states how many bytes can be read or skipped without blocking.

		<p>Note: This method offers no information on whether the EOF
		has been reached.  </p>
	 */
	long available()
			raises( com::sun::star::io::NotConnectedException,
					com::sun::star::io::IOException
					);

	//-------------------------------------------------------------------------

	// DocMerge from xml: method com::sun::star::io::XInputStream::closeInput
	/** closes the stream.

		<p>Users must close the stream explicitly when no further
		reading should be done. (There may exist ring references to
		chained objects that can only be released during this call.
		Thus not calling this method would result in a leak of memory or
		external resources.) </p>
	 */
	void closeInput()
			raises( com::sun::star::io::NotConnectedException,
					com::sun::star::io::IOException);

};

//=============================================================================

}; }; }; };

/*=============================================================================

=============================================================================*/
#endif