01: package com.quadcap.io;
02:
03: /* Copyright 1997 - 2003 Quadcap Software. All rights reserved.
04: *
05: * This software is distributed under the Quadcap Free Software License.
06: * This software may be used or modified for any purpose, personal or
07: * commercial. Open Source redistributions are permitted. Commercial
08: * redistribution of larger works derived from, or works which bundle
09: * this software requires a "Commercial Redistribution License"; see
10: * http://www.quadcap.com/purchase.
11: *
12: * Redistributions qualify as "Open Source" under one of the following terms:
13: *
14: * Redistributions are made at no charge beyond the reasonable cost of
15: * materials and delivery.
16: *
17: * Redistributions are accompanied by a copy of the Source Code or by an
18: * irrevocable offer to provide a copy of the Source Code for up to three
19: * years at the cost of materials and delivery. Such redistributions
20: * must allow further use, modification, and redistribution of the Source
21: * Code under substantially the same terms as this license.
22: *
23: * Redistributions of source code must retain the copyright notices as they
24: * appear in each source code file, these license terms, and the
25: * disclaimer/limitation of liability set forth as paragraph 6 below.
26: *
27: * Redistributions in binary form must reproduce this Copyright Notice,
28: * these license terms, and the disclaimer/limitation of liability set
29: * forth as paragraph 6 below, in the documentation and/or other materials
30: * provided with the distribution.
31: *
32: * The Software is provided on an "AS IS" basis. No warranty is
33: * provided that the Software is free of defects, or fit for a
34: * particular purpose.
35: *
36: * Limitation of Liability. Quadcap Software shall not be liable
37: * for any damages suffered by the Licensee or any third party resulting
38: * from use of the Software.
39: */
40:
41: import java.io.InputStream;
42: import java.io.IOException;
43:
44: /**
45: * This class implements a sort of 'head' operation, creating a new
46: * input stream as a filter stream on top of an existing stream, returning
47: * only the first "N" bytes.
48: *
49: * @author Stan Bailes
50: */
51: public class LimitedInputStream extends InputStream {
52: InputStream in;
53: int cnt = 0;
54: int limit;
55:
56: /**
57: * Construct a new LimitedInputStream, attached to the specified
58: * input stream and with the specified limit.
59: *
60: * @param in the input stream
61: * @param limit the number of bytes to read
62: */
63: public LimitedInputStream(InputStream in, int limit) {
64: this .in = in;
65: this .limit = limit;
66: }
67:
68: /**
69: * Read a byte from this stream, returning -1 if the underlying
70: * stream returns EOF, or if we've reached our limit.
71: *
72: * @exception IOException may be thrown
73: */
74: public int read() throws IOException {
75: if (cnt++ >= limit)
76: return -1;
77: return in.read();
78: }
79: }
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