001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018 package org.apache.commons.net.telnet;
019
020 /***
021 * Implements the telnet window size option RFC 1073.
022 * <p>
023 * @author Yuval Kashtan
024 * @version $Id: WindowSizeOptionHandler.java 1299238 2012-03-10 17:12:28Z sebb $
025 * @since 2.0
026 ***/
027 public class WindowSizeOptionHandler extends TelnetOptionHandler
028 {
029 /***
030 * Horizontal Size
031 ***/
032 private int m_nWidth = 80;
033
034 /***
035 * Vertical Size
036 ***/
037 private int m_nHeight = 24;
038
039 /***
040 * Window size option
041 ***/
042 protected static final int WINDOW_SIZE = 31;
043
044 /***
045 * Constructor for the WindowSizeOptionHandler. Allows defining desired
046 * initial setting for local/remote activation of this option and
047 * behaviour in case a local/remote activation request for this
048 * option is received.
049 * <p>
050 * @param nWidth - Window width.
051 * @param nHeight - Window Height
052 * @param initlocal - if set to true, a WILL is sent upon connection.
053 * @param initremote - if set to true, a DO is sent upon connection.
054 * @param acceptlocal - if set to true, any DO request is accepted.
055 * @param acceptremote - if set to true, any WILL request is accepted.
056 ***/
057 public WindowSizeOptionHandler(
058 int nWidth,
059 int nHeight,
060 boolean initlocal,
061 boolean initremote,
062 boolean acceptlocal,
063 boolean acceptremote
064 ) {
065 super (
066 TelnetOption.WINDOW_SIZE,
067 initlocal,
068 initremote,
069 acceptlocal,
070 acceptremote
071 );
072
073 m_nWidth = nWidth;
074 m_nHeight = nHeight;
075 }
076
077 /***
078 * Constructor for the WindowSizeOptionHandler. Initial and accept
079 * behaviour flags are set to false
080 * <p>
081 * @param nWidth - Window width.
082 * @param nHeight - Window Height
083 ***/
084 public WindowSizeOptionHandler(
085 int nWidth,
086 int nHeight
087 ) {
088 super (
089 TelnetOption.WINDOW_SIZE,
090 false,
091 false,
092 false,
093 false
094 );
095
096 m_nWidth = nWidth;
097 m_nHeight = nHeight;
098 }
099
100 /***
101 * Implements the abstract method of TelnetOptionHandler.
102 * <p>
103 * @param suboptionData - the sequence received, whithout IAC SB & IAC SE
104 * @param suboptionLength - the length of data in suboption_data
105 * <p>
106 * @return terminal type information
107 ***/
108 @Override
109 public int[] answerSubnegotiation(int suboptionData[], int suboptionLength)
110 {
111 return null;
112 }
113
114 /***
115 * Implements the abstract method of TelnetOptionHandler.
116 * This will send the client Height and Width to the server.
117 * <p>
118 * @return array to send to remote system
119 ***/
120 @Override
121 public int[] startSubnegotiationLocal()
122 {
123 int nCompoundWindowSize = m_nWidth * 0x10000 + m_nHeight;
124 int nResponseSize = 5;
125 int nIndex;
126 int nShift;
127 int nTurnedOnBits;
128
129 if ((m_nWidth % 0x100) == 0xFF) {
130 nResponseSize += 1;
131 }
132
133 if ((m_nWidth / 0x100) == 0xFF) {
134 nResponseSize += 1;
135 }
136
137 if ((m_nHeight % 0x100) == 0xFF) {
138 nResponseSize += 1;
139 }
140
141 if ((m_nHeight / 0x100) == 0xFF) {
142 nResponseSize += 1;
143 }
144
145 //
146 // allocate response array
147 //
148 int response[] = new int[nResponseSize];
149
150 //
151 // Build response array.
152 // ---------------------
153 // 1. put option name.
154 // 2. loop through Window size and fill the values,
155 // 3. duplicate 'ff' if needed.
156 //
157
158 response[0] = WINDOW_SIZE; // 1 //
159
160 for ( // 2 //
161 nIndex=1, nShift = 24;
162 nIndex < nResponseSize;
163 nIndex++, nShift -=8
164 ) {
165 nTurnedOnBits = 0xFF;
166 nTurnedOnBits <<= nShift;
167 response[nIndex] = (nCompoundWindowSize & nTurnedOnBits) >>> nShift;
168
169 if (response[nIndex] == 0xff) { // 3 //
170 nIndex++;
171 response[nIndex] = 0xff;
172 }
173 }
174
175 return response;
176 }
177
178 /***
179 * Implements the abstract method of TelnetOptionHandler.
180 * <p>
181 * @return always null (no response to subnegotiation)
182 ***/
183 @Override
184 public int[] startSubnegotiationRemote()
185 {
186 return null;
187 }
188 }