org.apache.commons.net.telnet.WindowSizeOptionHandler Maven / Gradle / Ivy
/*
* 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.
*/
package org.apache.commons.net.telnet;
/***
* Implements the telnet window size option RFC 1073.
* @version $Id: WindowSizeOptionHandler.java 1697293 2015-08-24 01:01:00Z sebb $
* @since 2.0
***/
public class WindowSizeOptionHandler extends TelnetOptionHandler
{
/***
* Horizontal Size
***/
private int m_nWidth = 80;
/***
* Vertical Size
***/
private int m_nHeight = 24;
/***
* Window size option
***/
protected static final int WINDOW_SIZE = 31;
/***
* Constructor for the WindowSizeOptionHandler. Allows defining desired
* initial setting for local/remote activation of this option and
* behaviour in case a local/remote activation request for this
* option is received.
*
* @param nWidth - Window width.
* @param nHeight - Window Height
* @param initlocal - if set to true, a WILL is sent upon connection.
* @param initremote - if set to true, a DO is sent upon connection.
* @param acceptlocal - if set to true, any DO request is accepted.
* @param acceptremote - if set to true, any WILL request is accepted.
***/
public WindowSizeOptionHandler(
int nWidth,
int nHeight,
boolean initlocal,
boolean initremote,
boolean acceptlocal,
boolean acceptremote
) {
super (
TelnetOption.WINDOW_SIZE,
initlocal,
initremote,
acceptlocal,
acceptremote
);
m_nWidth = nWidth;
m_nHeight = nHeight;
}
/***
* Constructor for the WindowSizeOptionHandler. Initial and accept
* behaviour flags are set to false
*
* @param nWidth - Window width.
* @param nHeight - Window Height
***/
public WindowSizeOptionHandler(
int nWidth,
int nHeight
) {
super (
TelnetOption.WINDOW_SIZE,
false,
false,
false,
false
);
m_nWidth = nWidth;
m_nHeight = nHeight;
}
/***
* Implements the abstract method of TelnetOptionHandler.
* This will send the client Height and Width to the server.
*
* @return array to send to remote system
***/
@Override
public int[] startSubnegotiationLocal()
{
int nCompoundWindowSize = m_nWidth * 0x10000 + m_nHeight;
int nResponseSize = 5;
int nIndex;
int nShift;
int nTurnedOnBits;
if ((m_nWidth % 0x100) == 0xFF) {
nResponseSize += 1;
}
if ((m_nWidth / 0x100) == 0xFF) {
nResponseSize += 1;
}
if ((m_nHeight % 0x100) == 0xFF) {
nResponseSize += 1;
}
if ((m_nHeight / 0x100) == 0xFF) {
nResponseSize += 1;
}
//
// allocate response array
//
int response[] = new int[nResponseSize];
//
// Build response array.
// ---------------------
// 1. put option name.
// 2. loop through Window size and fill the values,
// 3. duplicate 'ff' if needed.
//
response[0] = WINDOW_SIZE; // 1 //
for ( // 2 //
nIndex=1, nShift = 24;
nIndex < nResponseSize;
nIndex++, nShift -=8
) {
nTurnedOnBits = 0xFF;
nTurnedOnBits <<= nShift;
response[nIndex] = (nCompoundWindowSize & nTurnedOnBits) >>> nShift;
if (response[nIndex] == 0xff) { // 3 //
nIndex++;
response[nIndex] = 0xff;
}
}
return response;
}
}