001/*
002 * Copyright 2006 - 2013
003 *     Stefan Balev     <stefan.balev@graphstream-project.org>
004 *     Julien Baudry    <julien.baudry@graphstream-project.org>
005 *     Antoine Dutot    <antoine.dutot@graphstream-project.org>
006 *     Yoann Pigné      <yoann.pigne@graphstream-project.org>
007 *     Guilhelm Savin   <guilhelm.savin@graphstream-project.org>
008 * 
009 * This file is part of GraphStream <http://graphstream-project.org>.
010 * 
011 * GraphStream is a library whose purpose is to handle static or dynamic
012 * graph, create them from scratch, file or any source and display them.
013 * 
014 * This program is free software distributed under the terms of two licenses, the
015 * CeCILL-C license that fits European law, and the GNU Lesser General Public
016 * License. You can  use, modify and/ or redistribute the software under the terms
017 * of the CeCILL-C license as circulated by CEA, CNRS and INRIA at the following
018 * URL <http://www.cecill.info> or under the terms of the GNU LGPL as published by
019 * the Free Software Foundation, either version 3 of the License, or (at your
020 * option) any later version.
021 * 
022 * This program is distributed in the hope that it will be useful, but WITHOUT ANY
023 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
024 * PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more details.
025 * 
026 * You should have received a copy of the GNU Lesser General Public License
027 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
028 * 
029 * The fact that you are presently reading this means that you have had
030 * knowledge of the CeCILL-C and LGPL licenses and that you accept their terms.
031 */
032package org.graphstream.stream.netstream.packing;
033
034import java.nio.ByteBuffer;
035
036/**
037 * 
038 */
039public abstract class NetStreamUnpacker {
040        
041        /**
042         * An unpacker has to be abble to indicated what is the size of an int after being packed.
043         * @return
044         */
045        public abstract int sizeOfInt();
046        
047        /**
048         * Unpack the given ByteBuffer from startIndex to endIdex 
049         * @param buffer The buffer to unpack/decode
050         * @param startIndex the index at which the decoding starts in the buffer
051         * @param endIndex the index at which the decoding stops
052         * @return a ByteBuffer that is the unpacked version of the input one. It may not have the same size.
053         */
054        public abstract ByteBuffer unpackMessage(ByteBuffer buffer, int startIndex, int endIndex);
055
056        /**
057         * Unpack the given ByteBuffer 
058         * @param buffer The buffer to unpack/decode
059         * @return a ByteBuffer that is the unpacked version of the input one. It may not have the same size.
060         */
061        public ByteBuffer unpackMessage(ByteBuffer buffer){
062                return this.unpackMessage(buffer, 0, buffer.capacity());
063        }
064
065        /**
066         * Unpacks the data necessary to decode a 4 bytes integer that indicates the size of the following message. 
067         * 
068         * The given buffer's position may be important for the unpacker to work. This method may also change the given bytebuffer's position attribute. 
069         * 
070         * @param buffer The byteBuffer who's content has the encoded value of the needed  size integer.
071         * @return
072         */
073        public abstract int unpackMessageSize(ByteBuffer buffer);
074        
075        
076        
077}