xref: /trunk/main/udkapi/com/sun/star/io/XInputStream.idl (revision ffd38472365e95f6a578737bc9a5eb0fac624a86)

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 * Licensed to the Apache Software Foundation (ASF) under one
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 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
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#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., between 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 synchronous 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 behavior.
           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