libjava/classpath/gnu/java/net/CRLFInputStream.java

   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 }
 174