/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (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.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Mozilla FastLoad code.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 2001
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */


/*
 * nsISeekableStream
 *
 * Note that a stream might not implement all methods (e.g., a readonly stream 
 * won't implement setEOF)
 * 
 * @status UNDER_REVIEW
 */

#include "nsISupports.idl"

[scriptable, uuid(8429d350-1040-4661-8b71-f2a6ba455980)]
interface nsISeekableStream : nsISupports
{
    /* 
     * Sets the stream pointer to the value of the 'offset' parameter 
     */
    const PRInt32 NS_SEEK_SET = 0;

    /*  
     * Sets the stream pointer to its current location plus the value 
     * of the offset parameter. 
     */
    const PRInt32 NS_SEEK_CUR = 1;

    /* 
     * Sets the stream pointer to the size of the stream plus the value 
     * of the offset parameter. 
     */
    const PRInt32 NS_SEEK_END = 2;

    /**
     *  seek
     *
     *  This method moves the stream offset of the steam implementing this
     *  interface.
     *
     *   @param whence specifies how to interpret the 'offset' parameter in
     *                 setting the stream offset associated with the implementing
     *                 stream.
     *     
     *   @param offset specifies a value, in bytes, that is used in conjunction
     *                 with the 'whence' parameter to set the stream offset of the 
     *                 implementing stream.  A negative value causes seeking in 
     *                 the reverse direction.
     *
     *   @throws NS_BASE_STREAM_CLOSED if called on a closed stream.
     */
    void seek(in long whence, in long long offset);

    /**
     *  tell
     *
     *  This method reports the current offset, in bytes, from the start of the 
     *  stream. 
     *
     *   @throws NS_BASE_STREAM_CLOSED if called on a closed stream.
     */
    long long tell();


    /**
     *  setEOF
     *
     *  This method truncates the stream at the current offset.
     *
     *   @throws NS_BASE_STREAM_CLOSED if called on a closed stream.
     */
    void setEOF();
};