gomp-20050608-branch/libjava/classpath/gnu/java/net/CRLFOutputStream.java

   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    */
  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    */
  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    */
 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    */
 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    */
 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    */
 177   public void writeln()
 178     throws IOException
 179   {
 180     out.write(CRLF, 0, 2);
 181   }
 182 }
 183