1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18 package org.apache.commons.net.io; 19 20 import java.io.FilterOutputStream; 21 import java.io.IOException; 22 import java.io.OutputStream; 23 24 /*** 25 * This class wraps an output stream, replacing all singly occurring 26 * <LF> (linefeed) characters with <CR><LF> (carriage return 27 * followed by linefeed), which is the NETASCII standard for representing 28 * a newline. 29 * You would use this class to implement ASCII file transfers requiring 30 * conversion to NETASCII. 31 * <p> 32 * <p> 33 * @author Daniel F. Savarese 34 ***/ 35 36 public final class ToNetASCIIOutputStream extends FilterOutputStream 37 { 38 private boolean __lastWasCR; 39 40 /*** 41 * Creates a ToNetASCIIOutputStream instance that wraps an existing 42 * OutputStream. 43 * <p> 44 * @param output The OutputStream to wrap. 45 ***/ 46 public ToNetASCIIOutputStream(OutputStream output) 47 { 48 super(output); 49 __lastWasCR = false; 50 } 51 52 53 /*** 54 * Writes a byte to the stream. Note that a call to this method 55 * may result in multiple writes to the underlying input stream in order 56 * to convert naked newlines to NETASCII line separators. 57 * This is transparent to the programmer and is only mentioned for 58 * completeness. 59 * <p> 60 * @param ch The byte to write. 61 * @exception IOException If an error occurs while writing to the underlying 62 * stream. 63 ***/ 64 @Override 65 public synchronized void write(int ch) 66 throws IOException 67 { 68 switch (ch) 69 { 70 case '\r': 71 __lastWasCR = true; 72 out.write('\r'); 73 return ; 74 case '\n': 75 if (!__lastWasCR) 76 out.write('\r'); 77 // Fall through 78 default: 79 __lastWasCR = false; 80 out.write(ch); 81 return ; 82 } 83 } 84 85 86 /*** 87 * Writes a byte array to the stream. 88 * <p> 89 * @param buffer The byte array to write. 90 * @exception IOException If an error occurs while writing to the underlying 91 * stream. 92 ***/ 93 @Override 94 public synchronized void write(byte buffer[]) 95 throws IOException 96 { 97 write(buffer, 0, buffer.length); 98 } 99 100 101 /*** 102 * Writes a number of bytes from a byte array to the stream starting from 103 * a given offset. 104 * <p> 105 * @param buffer The byte array to write. 106 * @param offset The offset into the array at which to start copying data. 107 * @param length The number of bytes to write. 108 * @exception IOException If an error occurs while writing to the underlying 109 * stream. 110 ***/ 111 @Override 112 public synchronized void write(byte buffer[], int offset, int length) 113 throws IOException 114 { 115 while (length-- > 0) 116 write(buffer[offset++]); 117 } 118 119 }