1 /* BlockInputStream.java --
2    Copyright (C) 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.protocol.ftp;
40 
41 import java.io.IOException;
42 import java.io.InputStream;
43 
44 /**
45  * A DTP input stream that implements the FTP block transfer mode.
46  *
47  * @author Chris Burdess (dog@gnu.org)
48  */
49 class BlockInputStream
50   extends DTPInputStream
51 {
52 
53   static final int EOF = 64;
54 
55   int descriptor;
56   int max = -1;
57   int count = -1;
58 
BlockInputStream(DTP dtp, InputStream in)59   BlockInputStream(DTP dtp, InputStream in)
60   {
61     super(dtp, in);
62   }
63 
read()64   public int read()
65     throws IOException
66   {
67     if (transferComplete)
68       {
69         return -1;
70       }
71     if (count == -1)
72       {
73         readHeader();
74       }
75     if (max < 1)
76       {
77         close();
78         return -1;
79       }
80     int c = in.read();
81     if (c == -1)
82       {
83         dtp.transferComplete();
84       }
85     count++;
86     if (count >= max)
87       {
88         count = -1;
89         if (descriptor == EOF)
90           {
91             close();
92           }
93       }
94     return c;
95   }
96 
read(byte[] buf)97   public int read(byte[] buf)
98     throws IOException
99   {
100     return read(buf, 0, buf.length);
101   }
102 
read(byte[] buf, int off, int len)103   public int read(byte[] buf, int off, int len)
104     throws IOException
105   {
106     if (transferComplete)
107       {
108         return -1;
109       }
110     if (count == -1)
111       {
112         readHeader();
113       }
114     if (max < 1)
115       {
116         close();
117         return -1;
118       }
119     int l = in.read(buf, off, len);
120     if (l == -1)
121       {
122         dtp.transferComplete();
123       }
124     count += l;
125     if (count >= max)
126       {
127         count = -1;
128         if (descriptor == EOF)
129           {
130             close();
131           }
132       }
133     return l;
134   }
135 
136   /**
137    * Reads the block header.
138    */
readHeader()139   void readHeader()
140     throws IOException
141   {
142     descriptor = in.read();
143     int max_hi = in.read();
144     int max_lo = in.read();
145     max = (max_hi << 8) | max_lo;
146     count = 0;
147   }
148 
149 }
150