Source for gnu.java.net.CRLFInputStream

   1: /* CRLFInputStream.java --
   2:    Copyright (C) 2002, 2003, 2004, 2006  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.BufferedInputStream;
  42: import java.io.IOException;
  43: import java.io.InputStream;
  44: 
  45: /**
  46:  * An input stream that filters out CR/LF pairs into LFs.
  47:  *
  48:  * @author Chris Burdess (dog@gnu.org)
  49:  */
  50: public class CRLFInputStream
  51:   extends InputStream
  52: {
  53:   /**
  54:    * The CR octet.
  55:    */
  56:   public static final int CR = 13;
  57: 
  58:   /**
  59:    * The LF octet.
  60:    */
  61:   public static final int LF = 10;
  62: 
  63:   /**
  64:    * The underlying input stream.
  65:    */
  66:   protected InputStream in;
  67: 
  68:   private boolean doReset;
  69: 
  70:   /**
  71:    * Constructs a CR/LF input stream connected to the specified input
  72:    * stream.
  73:    */
  74:   public CRLFInputStream(InputStream in)
  75:   {
  76:     this.in = in.markSupported() ? in : new BufferedInputStream(in);
  77:   }
  78: 
  79:   /**
  80:    * Reads the next byte of data from this input stream.
  81:    * Returns -1 if the end of the stream has been reached.
  82:    * @exception IOException if an I/O error occurs
  83:    */
  84:   public int read()
  85:     throws IOException
  86:   {
  87:     int c = in.read();
  88:     if (c == CR)
  89:       {
  90:         in.mark(1);
  91:         int d = in.read();
  92:         if (d == LF)
  93:           {
  94:             c = d;
  95:           }
  96:         else
  97:           {
  98:             in.reset();
  99:           }
 100:       }
 101:     return c;
 102:   }
 103: 
 104:   /**
 105:    * Reads up to b.length bytes of data from this input stream into
 106:    * an array of bytes.
 107:    * Returns -1 if the end of the stream has been reached.
 108:    * @exception IOException if an I/O error occurs
 109:    */
 110:   public int read(byte[] b)
 111:     throws IOException
 112:   {
 113:     return read(b, 0, b.length);
 114:   }
 115: 
 116:   /**
 117:    * Reads up to len bytes of data from this input stream into an
 118:    * array of bytes, starting at the specified offset.
 119:    * Returns -1 if the end of the stream has been reached.
 120:    * @exception IOException if an I/O error occurs
 121:    */
 122:   public int read(byte[] b, int off, int len)
 123:     throws IOException
 124:   {
 125:     in.mark(len + 1);
 126:     int l = in.read(b, off, len);
 127:     if (l > 0)
 128:       {
 129:         int i = indexOfCRLF(b, off, l);
 130:         if (doReset)
 131:           {
 132:             in.reset();
 133:             if (i != -1)
 134:               {
 135:                 l = in.read(b, off, (i + 1) - off); // read to CR
 136:                 in.read(); // skip LF
 137:                 b[i] = LF; // fix CR as LF
 138:               }
 139:             else
 140:               {
 141:                 l = in.read(b, off, len); // CR(s) but no LF
 142:               }
 143:           }
 144:       }
 145:     return l;
 146:   }
 147: 
 148:   private int indexOfCRLF(byte[] b, int off, int len)
 149:     throws IOException
 150:   {
 151:     doReset = false;
 152:     int end = off + len;
 153:     int em1 = end - 1;
 154:     for (int i = off; i < end; i++)
 155:       {
 156:         if (b[i] == CR)
 157:           {
 158:             int d;
 159:             if (i == em1)
 160:               {
 161:                 d = in.read();
 162:                 doReset = true;
 163:               }
 164:             else
 165:               {
 166:                 d = b[i + 1];
 167:               }
 168:             if (d == LF)
 169:               {
 170:                 doReset = true;
 171:                 return i;
 172:               }
 173:           }
 174:       }
 175:     return -1;
 176:   }
 177: 
 178: }