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.io; 019 020import java.io.FilterOutputStream; 021import java.io.IOException; 022import java.io.OutputStream; 023 024/*** 025 * This class wraps an output stream, replacing all occurrences 026 * of <CR><LF> (carriage return followed by a linefeed), 027 * which is the NETASCII standard for representing a newline, with the 028 * local line separator representation. You would use this class to 029 * implement ASCII file transfers requiring conversion from NETASCII. 030 * <p> 031 * Because of the translation process, a call to <code>flush()</code> will 032 * not flush the last byte written if that byte was a carriage 033 * return. A call to {@link #close close() }, however, will 034 * flush the carriage return. 035 * 036 * 037 ***/ 038 039public final class FromNetASCIIOutputStream extends FilterOutputStream 040{ 041 private boolean __lastWasCR; 042 043 /*** 044 * Creates a FromNetASCIIOutputStream instance that wraps an existing 045 * OutputStream. 046 * 047 * @param output The OutputStream to wrap. 048 ***/ 049 public FromNetASCIIOutputStream(OutputStream output) 050 { 051 super(output); 052 __lastWasCR = false; 053 } 054 055 056 private void __write(int ch) throws IOException 057 { 058 switch (ch) 059 { 060 case '\r': 061 __lastWasCR = true; 062 // Don't write anything. We need to see if next one is linefeed 063 break; 064 case '\n': 065 if (__lastWasCR) 066 { 067 out.write(FromNetASCIIInputStream._lineSeparatorBytes); 068 __lastWasCR = false; 069 break; 070 } 071 __lastWasCR = false; 072 out.write('\n'); 073 break; 074 default: 075 if (__lastWasCR) 076 { 077 out.write('\r'); 078 __lastWasCR = false; 079 } 080 out.write(ch); 081 break; 082 } 083 } 084 085 086 /*** 087 * Writes a byte to the stream. Note that a call to this method 088 * might not actually write a byte to the underlying stream until a 089 * subsequent character is written, from which it can be determined if 090 * a NETASCII line separator was encountered. 091 * This is transparent to the programmer and is only mentioned for 092 * completeness. 093 * 094 * @param ch The byte to write. 095 * @exception IOException If an error occurs while writing to the underlying 096 * stream. 097 ***/ 098 @Override 099 public synchronized void write(int ch) 100 throws IOException 101 { 102 if (FromNetASCIIInputStream._noConversionRequired) 103 { 104 out.write(ch); 105 return ; 106 } 107 108 __write(ch); 109 } 110 111 112 /*** 113 * Writes a byte array to the stream. 114 * 115 * @param buffer The byte array to write. 116 * @exception IOException If an error occurs while writing to the underlying 117 * stream. 118 ***/ 119 @Override 120 public synchronized void write(byte buffer[]) 121 throws IOException 122 { 123 write(buffer, 0, buffer.length); 124 } 125 126 127 /*** 128 * Writes a number of bytes from a byte array to the stream starting from 129 * a given offset. 130 * 131 * @param buffer The byte array to write. 132 * @param offset The offset into the array at which to start copying data. 133 * @param length The number of bytes to write. 134 * @exception IOException If an error occurs while writing to the underlying 135 * stream. 136 ***/ 137 @Override 138 public synchronized void write(byte buffer[], int offset, int length) 139 throws IOException 140 { 141 if (FromNetASCIIInputStream._noConversionRequired) 142 { 143 // FilterOutputStream method is very slow. 144 //super.write(buffer, offset, length); 145 out.write(buffer, offset, length); 146 return ; 147 } 148 149 while (length-- > 0) { 150 __write(buffer[offset++]); 151 } 152 } 153 154 155 /*** 156 * Closes the stream, writing all pending data. 157 * 158 * @exception IOException If an error occurs while closing the stream. 159 ***/ 160 @Override 161 public synchronized void close() 162 throws IOException 163 { 164 if (FromNetASCIIInputStream._noConversionRequired) 165 { 166 super.close(); 167 return ; 168 } 169 170 if (__lastWasCR) { 171 out.write('\r'); 172 } 173 super.close(); 174 } 175}