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    */
CRLFInputStream(InputStream in)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    */
read()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    */
read(byte[] b)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    */
read(byte[] b, int off, int len)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 
indexOfCRLF(byte[] b, int off, int len)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 
175