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 singly occurring 026 * <LF> (linefeed) characters with <CR><LF> (carriage return 027 * followed by linefeed), which is the NETASCII standard for representing 028 * a newline. 029 * You would use this class to implement ASCII file transfers requiring 030 * conversion to NETASCII. 031 * 032 * 033 */ 034 035public final class ToNetASCIIOutputStream extends FilterOutputStream 036{ 037 private boolean lastWasCR; 038 039 /** 040 * Creates a ToNetASCIIOutputStream instance that wraps an existing 041 * OutputStream. 042 * 043 * @param output The OutputStream to wrap. 044 */ 045 public ToNetASCIIOutputStream(final OutputStream output) 046 { 047 super(output); 048 lastWasCR = false; 049 } 050 051 052 /** 053 * Writes a byte to the stream. Note that a call to this method 054 * may result in multiple writes to the underlying input stream in order 055 * to convert naked newlines to NETASCII line separators. 056 * This is transparent to the programmer and is only mentioned for 057 * completeness. 058 * 059 * @param ch The byte to write. 060 * @throws IOException If an error occurs while writing to the underlying 061 * stream. 062 */ 063 @Override 064 public synchronized void write(final int ch) 065 throws IOException 066 { 067 switch (ch) 068 { 069 case '\r': 070 lastWasCR = true; 071 out.write('\r'); 072 return ; 073 case '\n': 074 if (!lastWasCR) { 075 out.write('\r'); 076 } 077 //$FALL-THROUGH$ 078 default: 079 lastWasCR = false; 080 out.write(ch); 081 } 082 } 083 084 085 /** 086 * Writes a byte array to the stream. 087 * 088 * @param buffer The byte array to write. 089 * @throws IOException If an error occurs while writing to the underlying 090 * stream. 091 */ 092 @Override 093 public synchronized void write(final byte buffer[]) 094 throws IOException 095 { 096 write(buffer, 0, buffer.length); 097 } 098 099 100 /** 101 * Writes a number of bytes from a byte array to the stream starting from 102 * a given offset. 103 * 104 * @param buffer The byte array to write. 105 * @param offset The offset into the array at which to start copying data. 106 * @param length The number of bytes to write. 107 * @throws IOException If an error occurs while writing to the underlying 108 * stream. 109 */ 110 @Override 111 public synchronized void write(final byte buffer[], int offset, int length) 112 throws IOException 113 { 114 while (length-- > 0) { 115 write(buffer[offset++]); 116 } 117 } 118 119}