Source for gnu.java.net.CRLFOutputStream

   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: }