1/*
2 * Copyright (c) 2002, 2003, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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23 * questions.
24 */
25
26package sun.nio.ch;
27
28
29// Constants for reporting I/O status
30
31final class IOStatus {
32
33    private IOStatus() { }
34
35    static final int EOF = -1;              // End of file
36    static final int UNAVAILABLE = -2;      // Nothing available (non-blocking)
37    static final int INTERRUPTED = -3;      // System call interrupted
38    static final int UNSUPPORTED = -4;      // Operation not supported
39    static final int THROWN = -5;           // Exception thrown in JNI code
40    static final int UNSUPPORTED_CASE = -6; // This case not supported
41
42    // The following two methods are for use in try/finally blocks where a
43    // status value needs to be normalized before being returned to the invoker
44    // but also checked for illegal negative values before the return
45    // completes, like so:
46    //
47    //     int n = 0;
48    //     try {
49    //         begin();
50    //         n = op(fd, buf, ...);
51    //         return IOStatus.normalize(n);    // Converts UNAVAILABLE to zero
52    //     } finally {
53    //         end(n > 0);
54    //         assert IOStatus.check(n);        // Checks other negative values
55    //     }
56    //
57
58    static int normalize(int n) {
59        if (n == UNAVAILABLE)
60            return 0;
61        return n;
62    }
63
64    static boolean check(int n) {
65        return (n >= UNAVAILABLE);
66    }
67
68    static long normalize(long n) {
69        if (n == UNAVAILABLE)
70            return 0;
71        return n;
72    }
73
74    static boolean check(long n) {
75        return (n >= UNAVAILABLE);
76    }
77
78    // Return true iff n is not one of the IOStatus values
79    static boolean checkAll(long n) {
80        return ((n > EOF) || (n < UNSUPPORTED_CASE));
81    }
82
83}
84