Source for gnu.java.net.CRLFInputStream

   1: /* CRLFInputStream.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.BufferedInputStream;
  42: import java.io.FilterInputStream;
  43: import java.io.IOException;
  44: import java.io.InputStream;
  45: 
  46: /**
  47:  * An input stream that filters out CR/LF pairs into LFs.
  48:  *
  49:  * @author Chris Burdess (dog@gnu.org)
  50:  */
  51: public class CRLFInputStream
  52:   extends FilterInputStream
  53: {
  54:   /**
  55:    * The CR octet.
  56:    */
  57:   public static final int CR = 13;
  58: 
  59:   /**
  60:    * The LF octet.
  61:    */
  62:   public static final int LF = 10;
  63: 
  64:   private boolean doReset;
  65: 
  66:   /**
  67:    * Constructs a CR/LF input stream connected to the specified input
  68:    * stream.
  69:    */
  70:   public CRLFInputStream(InputStream in)
  71:   {
  72:     super(in.markSupported() ? in : new BufferedInputStream(in));
  73:   }
  74: 
  75:   /**
  76:    * Reads the next byte of data from this input stream.
  77:    * Returns -1 if the end of the stream has been reached.
  78:    * @exception IOException if an I/O error occurs
  79:    */
  80:   public int read()
  81:     throws IOException
  82:   {
  83:     int c = in.read();
  84:     if (c == CR)
  85:       {
  86:         in.mark(1);
  87:         int d = in.read();
  88:         if (d == LF)
  89:           {
  90:             c = d;
  91:           }
  92:         else
  93:           {
  94:             in.reset();
  95:           }
  96:       }
  97:     return c;
  98:   }
  99:   
 100:   /**
 101:    * Reads up to b.length bytes of data from this input stream into
 102:    * an array of bytes.
 103:    * Returns -1 if the end of the stream has been reached.
 104:    * @exception IOException if an I/O error occurs
 105:    */
 106:   public int read(byte[] b)
 107:     throws IOException
 108:   {
 109:     return read(b, 0, b.length);
 110:   }
 111: 
 112:   /**
 113:    * Reads up to len bytes of data from this input stream into an
 114:    * array of bytes, starting at the specified offset.
 115:    * Returns -1 if the end of the stream has been reached.
 116:    * @exception IOException if an I/O error occurs
 117:    */
 118:   public int read(byte[] b, int off, int len)
 119:     throws IOException
 120:   {
 121:     in.mark(len + 1);
 122:     int l = in.read(b, off, len);
 123:     if (l > 0)
 124:       {
 125:         int i = indexOfCRLF(b, off, l);
 126:         if (doReset)
 127:           {
 128:             in.reset();
 129:             if (i != -1)
 130:               {
 131:                 l = in.read(b, off, i + 1); // read to CR
 132:                 in.read(); // skip LF
 133:                 b[i] = LF; // fix CR as LF
 134:               }
 135:             else
 136:               {
 137:                 l = in.read(b, off, len); // CR(s) but no LF
 138:               }
 139:           }
 140:       }
 141:     return l;
 142:   }
 143: 
 144:   private int indexOfCRLF(byte[] b, int off, int len)
 145:     throws IOException
 146:   {
 147:     doReset = false;
 148:     int lm1 = len - 1;
 149:     for (int i = off; i < len; i++)
 150:       {
 151:         if (b[i] == CR)
 152:           {
 153:             int d;
 154:             if (i == lm1)
 155:               {
 156:                 d = in.read();
 157:                 doReset = true;
 158:               }
 159:             else
 160:               {
 161:                 d = b[i + 1];
 162:               }
 163:             if (d == LF)
 164:               {
 165:                 doReset = true;
 166:                 return i;
 167:               }
 168:           }
 169:       }
 170:     return -1;
 171:   }
 172: 
 173: }