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    */
CRLFInputStream(InputStream in)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    */
read()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    */
read(byte[] b)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    */
read(byte[] b, int off, int len)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 
indexOfCRLF(byte[] b, int off, int len)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 }
179