1 /* CRLFOutputStream.java -- 2 Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc. 3 4 This file is part of GNU Classpath. 5 6 GNU Classpath is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 2, or (at your option) 9 any later version. 10 11 GNU Classpath is distributed in the hope that it will be useful, but 12 WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 General Public License for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with GNU Classpath; see the file COPYING. If not, write to the 18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 19 02110-1301 USA. 20 21 Linking this library statically or dynamically with other modules is 22 making a combined work based on this library. Thus, the terms and 23 conditions of the GNU General Public License cover the whole 24 combination. 25 26 As a special exception, the copyright holders of this library give you 27 permission to link this library with independent modules to produce an 28 executable, regardless of the license terms of these independent 29 modules, and to copy and distribute the resulting executable under 30 terms of your choice, provided that you also meet, for each linked 31 independent module, the terms and conditions of the license of that 32 module. An independent module is a module which is not derived from 33 or based on this library. If you modify this library, you may extend 34 this exception to your version of the library, but you are not 35 obligated to do so. If you do not wish to do so, delete this 36 exception statement from your version. */ 37 38 39 package gnu.java.net; 40 41 import java.io.FilterOutputStream; 42 import java.io.IOException; 43 import java.io.OutputStream; 44 import java.io.UnsupportedEncodingException; 45 46 /** 47 * An output stream that filters LFs into CR/LF pairs. 48 * 49 * @author Chris Burdess (dog@gnu.org) 50 */ 51 public class CRLFOutputStream 52 extends FilterOutputStream 53 { 54 static final String US_ASCII = "US-ASCII"; 55 56 /** 57 * The CR octet. 58 */ 59 public static final int CR = 13; 60 61 /** 62 * The LF octet. 63 */ 64 public static final int LF = 10; 65 66 /** 67 * The CR/LF pair. 68 */ 69 public static final byte[] CRLF = { CR, LF }; 70 71 /** 72 * The last byte read. 73 */ 74 protected int last; 75 76 /** 77 * Constructs a CR/LF output stream connected to the specified output stream. 78 */ CRLFOutputStream(OutputStream out)79 public CRLFOutputStream(OutputStream out) 80 { 81 super(out); 82 last = -1; 83 } 84 85 /** 86 * Writes a character to the underlying stream. 87 * @exception IOException if an I/O error occurred 88 */ write(int ch)89 public void write(int ch) throws IOException 90 { 91 if (ch == CR) 92 { 93 out.write(CRLF); 94 } 95 else if (ch == LF) 96 { 97 if (last != CR) 98 { 99 out.write(CRLF); 100 } 101 } 102 else 103 { 104 out.write(ch); 105 } 106 last = ch; 107 } 108 109 /** 110 * Writes a byte array to the underlying stream. 111 * @exception IOException if an I/O error occurred 112 */ write(byte[] b)113 public void write(byte[] b) 114 throws IOException 115 { 116 write(b, 0, b.length); 117 } 118 119 /** 120 * Writes a portion of a byte array to the underlying stream. 121 * @exception IOException if an I/O error occurred 122 */ write(byte[] b, int off, int len)123 public void write(byte[] b, int off, int len) 124 throws IOException 125 { 126 int d = off; 127 len += off; 128 for (int i = off; i < len; i++) 129 { 130 switch (b[i]) 131 { 132 case CR: 133 out.write (b, d, i - d); 134 out.write (CRLF, 0, 2); 135 d = i + 1; 136 break; 137 case LF: 138 if (last != CR) 139 { 140 out.write (b, d, i - d); 141 out.write (CRLF, 0, 2); 142 } 143 d = i + 1; 144 break; 145 } 146 last = b[i]; 147 } 148 if (len - d > 0) 149 { 150 out.write (b, d, len - d); 151 } 152 } 153 154 /** 155 * Writes the specified ASCII string to the underlying stream. 156 * @exception IOException if an I/O error occurred 157 */ write(String text)158 public void write(String text) 159 throws IOException 160 { 161 try 162 { 163 byte[] bytes = text.getBytes(US_ASCII); 164 write(bytes, 0, bytes.length); 165 } 166 catch (UnsupportedEncodingException e) 167 { 168 throw new IOException("The US-ASCII encoding is not supported " + 169 "on this system"); 170 } 171 } 172 173 /** 174 * Writes a newline to the underlying stream. 175 * @exception IOException if an I/O error occurred 176 */ writeln()177 public void writeln() 178 throws IOException 179 { 180 out.write(CRLF, 0, 2); 181 } 182 } 183 184