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 018package org.apache.commons.net.telnet; 019 020/** 021 * Implements the telnet window size option RFC 1073. 022 * 023 * @since 2.0 024 */ 025public class WindowSizeOptionHandler extends TelnetOptionHandler { 026 /** 027 * Window size option 028 */ 029 protected static final int WINDOW_SIZE = 31; 030 031 /** 032 * Horizontal Size 033 */ 034 private int width = 80; 035 036 /** 037 * Vertical Size 038 */ 039 private int height = 24; 040 041 /** 042 * Constructor for the WindowSizeOptionHandler. Initial and accept behavior flags are set to false 043 * <p> 044 * 045 * @param nWidth - Window width. 046 * @param nHeight - Window Height 047 */ 048 public WindowSizeOptionHandler(final int nWidth, final int nHeight) { 049 super(TelnetOption.WINDOW_SIZE, false, false, false, false); 050 051 width = nWidth; 052 height = nHeight; 053 } 054 055 /** 056 * Constructor for the WindowSizeOptionHandler. Allows defining desired initial setting for local/remote activation of this option and behavior in case a 057 * local/remote activation request for this option is received. 058 * <p> 059 * 060 * @param nWidth - Window width. 061 * @param nHeight - Window Height 062 * @param initlocal - if set to true, a WILL is sent upon connection. 063 * @param initremote - if set to true, a DO is sent upon connection. 064 * @param acceptlocal - if set to true, any DO request is accepted. 065 * @param acceptremote - if set to true, any WILL request is accepted. 066 */ 067 public WindowSizeOptionHandler(final int nWidth, final int nHeight, final boolean initlocal, final boolean initremote, final boolean acceptlocal, 068 final boolean acceptremote) { 069 super(TelnetOption.WINDOW_SIZE, initlocal, initremote, acceptlocal, acceptremote); 070 071 width = nWidth; 072 height = nHeight; 073 } 074 075 /** 076 * Implements the abstract method of TelnetOptionHandler. This will send the client Height and Width to the server. 077 * <p> 078 * 079 * @return array to send to remote system 080 */ 081 @Override 082 public int[] startSubnegotiationLocal() { 083 final int nCompoundWindowSize = width * 0x10000 + height; 084 int nResponseSize = 5; 085 int nIndex; 086 int nShift; 087 int nTurnedOnBits; 088 089 if (width % 0x100 == 0xFF) { 090 nResponseSize += 1; 091 } 092 093 if (width / 0x100 == 0xFF) { 094 nResponseSize += 1; 095 } 096 097 if (height % 0x100 == 0xFF) { 098 nResponseSize += 1; 099 } 100 101 if (height / 0x100 == 0xFF) { 102 nResponseSize += 1; 103 } 104 105 // 106 // allocate response array 107 // 108 final int response[] = new int[nResponseSize]; 109 110 // 111 // Build response array. 112 // --------------------- 113 // 1. put option name. 114 // 2. loop through Window size and fill the values, 115 // 3. duplicate 'ff' if needed. 116 // 117 118 response[0] = WINDOW_SIZE; // 1 // 119 120 for ( // 2 // 121 nIndex = 1, nShift = 24; nIndex < nResponseSize; nIndex++, nShift -= 8) { 122 nTurnedOnBits = 0xFF; 123 nTurnedOnBits <<= nShift; 124 response[nIndex] = (nCompoundWindowSize & nTurnedOnBits) >>> nShift; 125 126 if (response[nIndex] == 0xff) { // 3 // 127 nIndex++; 128 response[nIndex] = 0xff; 129 } 130 } 131 132 return response; 133 } 134 135}