1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
|
/*
* Copyright (c) 2000, 2001, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/* @test
* @bug 4400571
* @summary Verify that ObjectInputStream.available() functions properly when
* called at the beginning of a data block, and that it does not
* attempt any read operations that may potentially block.
*/
import java.io.*;
public class Available {
public static void main(String[] args) throws Exception {
ObjectOutputStream oout;
ByteArrayOutputStream bout;
byte[] buf;
// write stream containing short data block
oout = new ObjectOutputStream(bout = new ByteArrayOutputStream());
oout.write(new byte[100]);
oout.close();
buf = bout.toByteArray();
// 4 byte stream header + 2 byte block header + data
if ((getAvailable(buf, 4) != 0) || (getAvailable(buf, 5) != 0)) {
throw new Error();
}
for (int i = 0; i < 100; i++) {
if (getAvailable(buf, 6 + i) != i) {
throw new Error();
}
}
// write stream containing long data block
oout = new ObjectOutputStream(bout = new ByteArrayOutputStream());
oout.write(new byte[500]);
oout.close();
buf = bout.toByteArray();
// 4 byte stream header + 5 byte block header + data
for (int i = 4; i < 9; i++) {
if (getAvailable(buf, i) != 0) {
throw new Error();
}
}
for (int i = 0; i < 500; i++) {
if (getAvailable(buf, 9 + i) != i) {
throw new Error();
}
}
}
/**
* Given a byte array containing a serialized stream, creates a copy of the
* given data truncated to the specified length, then returns the result of
* a call to available() on an ObjectInputStream created on top of the
* truncated data. As a side effect, a StreamCorrupted or EOFException
* will get thrown if the available() call attempts to read past the
* underlying stream's available data.
*/
static int getAvailable(byte[] data, int truncateLen) throws IOException {
byte[] trunc = new byte[truncateLen];
System.arraycopy(data, 0, trunc, 0, truncateLen);
return new ObjectInputStream(
new ByteArrayInputStream(trunc)).available();
}
}
|
