| J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2002-2003 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package sun.nio.ch; |
| 27 | |
| 28 | |
| 29 | // Constants for reporting I/O status |
| 30 | |
| 31 | final 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 | } |