/*

 * Copyright 2002-2003 Sun Microsystems, Inc.  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.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun in the LICENSE file that accompanied this code.

 *

 * 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package sun.nio.ch;

// Constants for reporting I/O status

final class IOStatus {

    private IOStatus() { }

    static final int EOF = -1;              // End of file

    static final int UNAVAILABLE = -2;      // Nothing available (non-blocking)

    static final int INTERRUPTED = -3;      // System call interrupted

    static final int UNSUPPORTED = -4;      // Operation not supported

    static final int THROWN = -5;           // Exception thrown in JNI code

    static final int UNSUPPORTED_CASE = -6; // This case not supported

    // The following two methods are for use in try/finally blocks where a

    // status value needs to be normalized before being returned to the invoker

    // but also checked for illegal negative values before the return

    // completes, like so:

    //

    //     int n = 0;

    //     try {

    //         begin();

    //         n = op(fd, buf, ...);

    //         return IOStatus.normalize(n);    // Converts UNAVAILABLE to zero

    //     } finally {

    //         end(n > 0);

    //         assert IOStatus.check(n);        // Checks other negative values

    //     }

    //

    static int normalize(int n) {

        if (n == UNAVAILABLE)

            return 0;

        return n;

    }

    static boolean check(int n) {

        return (n >= UNAVAILABLE);

    }

    static long normalize(long n) {

        if (n == UNAVAILABLE)

            return 0;

        return n;

    }

    static boolean check(long n) {

        return (n >= UNAVAILABLE);

    }

    // Return true iff n is not one of the IOStatus values

    static boolean checkAll(long n) {

        return ((n > EOF) || (n < UNSUPPORTED_CASE));

    }

}