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Java > Open Source Codes > com > imagero > uio > io > LimitedInputStream


1 /*
2  * Copyright (c) Andrey Kuznetsov. All Rights Reserved.
3  *
4  * http://uio.imagero.com
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions are met:
8  *
9  * o Redistributions of source code must retain the above copyright notice,
10  * this list of conditions and the following disclaimer.
11  *
12  * o Redistributions in binary form must reproduce the above copyright notice,
13  * this list of conditions and the following disclaimer in the documentation
14  * and/or other materials provided with the distribution.
15  *
16  * o Neither the name of imagero Andrei Kouznetsov nor the names of
17  * its contributors may be used to endorse or promote products derived
18  * from this software without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
21  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
22  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
23  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
24  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
25  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
26  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
27  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
28  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
29  * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
30  * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31  */
32 package com.imagero.uio.io;
33
34 import java.io.FilterInputStream JavaDoc;
35 import java.io.IOException JavaDoc;
36 import java.io.InputStream JavaDoc;
37
38 /**
39  * InputStream that reads specified number of bytes
40  *
41  * @author Kouznetsov Andrei
42  */
43 public class LimitedInputStream extends FilterInputStream JavaDoc {
44     protected int limit;
45
46     /**
47      * create new LimitedInputStream
48      *
49      * @param in
50      * @param limit read limit
51      */
52     public LimitedInputStream(InputStream JavaDoc in, int limit) {
53         super(in);
54         this.limit = limit;
55     }
56
57     public int available() throws IOException JavaDoc {
58         return limit;
59     }
60
61     public int read() throws IOException JavaDoc {
62         if(limit-- <= 0) {
63             return -1;
64         }
65         return in.read();
66     }
67
68     public int read(byte b[]) throws IOException JavaDoc {
69         return in.read(b, 0, b.length);
70     }
71
72     public int read(byte b[], int off, int len) throws IOException JavaDoc {
73         if(limit > 0) {
74             int length = Math.min(len, limit);
75             int res = in.read(b, off, length);
76             if(res > 0) {
77                 limit -= res;
78             }
79             return res;
80         }
81         return -1;
82     }
83
84     public long skip(long n) throws IOException JavaDoc {
85         if(limit > 0) {
86             long length = Math.min(n, limit);
87             long res = in.skip(length);
88             if(res > 0) {
89                 limit -= res;
90             }
91             return res;
92         }
93         return -1;
94     }
95
96     int mark;
97
98     public synchronized void mark(int readlimit) {
99         in.mark(readlimit);
100         mark = limit;
101     }
102
103     public synchronized void reset() throws IOException JavaDoc {
104         in.reset();
105         limit = mark;
106     }
107 }
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