1/*
2 * Copyright (c) 2002, 2013, 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
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26package sun.nio.ch;
27
28import java.lang.annotation.Native;
29
30// Constants for reporting I/O status
31
32public final class IOStatus {
33
34    private IOStatus() { }
35
36    @Native public static final int EOF = -1;              // End of file
37    @Native public static final int UNAVAILABLE = -2;      // Nothing available (non-blocking)
38    @Native public static final int INTERRUPTED = -3;      // System call interrupted
39    @Native public static final int UNSUPPORTED = -4;      // Operation not supported
40    @Native public static final int THROWN = -5;           // Exception thrown in JNI code
41    @Native public static final int UNSUPPORTED_CASE = -6; // This case not supported
42
43    // The following two methods are for use in try/finally blocks where a
44    // status value needs to be normalized before being returned to the invoker
45    // but also checked for illegal negative values before the return
46    // completes, like so:
47    //
48    //     int n = 0;
49    //     try {
50    //         begin();
51    //         n = op(fd, buf, ...);
52    //         return IOStatus.normalize(n);    // Converts UNAVAILABLE to zero
53    //     } finally {
54    //         end(n > 0);
55    //         assert IOStatus.check(n);        // Checks other negative values
56    //     }
57    //
58
59    public static int normalize(int n) {
60        if (n == UNAVAILABLE)
61            return 0;
62        return n;
63    }
64
65    public static boolean check(int n) {
66        return (n >= UNAVAILABLE);
67    }
68
69    public static long normalize(long n) {
70        if (n == UNAVAILABLE)
71            return 0;
72        return n;
73    }
74
75    public static boolean check(long n) {
76        return (n >= UNAVAILABLE);
77    }
78
79    // Return true iff n is not one of the IOStatus values
80    public static boolean checkAll(long n) {
81        return ((n > EOF) || (n < UNSUPPORTED_CASE));
82    }
83
84}
85