1 /***
2 * Redistribution and use in source and binary forms, with or without
3 * modification, are permitted provided that the following conditions are
4 * met :
5 *
6 * . Redistributions of source code must retain the above copyright
7 * notice, this list of conditions and the following disclaimer.
8 *
9 * . Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * . The name of the author may not be used to endorse or promote products
14 * derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
18 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
19 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
20 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
21 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
22 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
24 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
25 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 *
28 * $Id$
29 */
30
31 package palmed.edit.text;
32
33 import java.io.IOException;
34 import java.io.InputStream;
35
36 /***
37 * This class provides a means to split a stream into chunks.
38 *
39 * @author Mathieu Champlon
40 * @version $Revision$ $Date$
41 */
42 public final class MultiInputStream extends InputStream
43 {
44 /***
45 * The underlying stream.
46 */
47 private final InputStream stream_;
48 /***
49 * The size of each chunk.
50 */
51 private final int size_;
52 /***
53 * The remaining number of bytes in the current chunk.
54 */
55 private int remaining_;
56
57 /***
58 * Create a multi input stream.
59 *
60 * @param stream the stream
61 * @param size the size of each chunk
62 */
63 public MultiInputStream( final InputStream stream, final int size )
64 {
65 if( stream == null )
66 throw new IllegalArgumentException( "parameter 'stream' is null" );
67 if( size <= 0 )
68 throw new IllegalArgumentException( "parameter 'size' must be > 0" );
69 stream_ = stream;
70 size_ = size;
71 remaining_ = size;
72 }
73
74 /***
75 * {@inheritDoc}
76 */
77 public int read() throws IOException
78 {
79 if( remaining_ == 0 )
80 return -1;
81 final int b = stream_.read();
82 if( b == -1 )
83 return -1;
84 --remaining_;
85 return b;
86 }
87
88 /***
89 * {@inheritDoc}
90 */
91 public int read( final byte[] b ) throws IOException
92 {
93 return read( b, 0, b.length );
94 }
95
96 /***
97 * {@inheritDoc}
98 */
99 public int read( final byte[] b, final int off, final int len ) throws IOException
100 {
101 if( remaining_ == 0 )
102 return -1;
103 final int read = stream_.read( b, off, Math.min( remaining_, len ) );
104 if( read == -1 )
105 return -1;
106 remaining_ -= read;
107 return read;
108 }
109
110 /***
111 * {@inheritDoc}
112 */
113 public int available() throws IOException
114 {
115 return Math.min( remaining_, stream_.available() );
116 }
117
118 /***
119 * {@inheritDoc}
120 */
121 public void close() throws IOException
122 {
123 stream_.close();
124 }
125
126 /***
127 * {@inheritDoc}
128 */
129 public boolean markSupported()
130 {
131 return false;
132 }
133
134 /***
135 * Move to next chunk.
136 */
137 public void next()
138 {
139 remaining_ = size_;
140 }
141 }