/*

 * Copyright (c) 2005, 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.  Oracle designates this

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

 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package sun.nio.ch;

import java.io.FileDescriptor;

import java.io.IOException;

/*

 * Represents a key to a specific file on Windows

 */

public class FileKey {

    private long dwVolumeSerialNumber;

    private long nFileIndexHigh;

    private long nFileIndexLow;

    private FileKey() { }

    public static FileKey create(FileDescriptor fd) {

        FileKey fk = new FileKey();

        try {

            fk.init(fd);

        } catch (IOException ioe) {

            throw new Error(ioe);

        }

        return fk;

    }

    public int hashCode() {

        return (int)(dwVolumeSerialNumber ^ (dwVolumeSerialNumber >>> 32)) +

               (int)(nFileIndexHigh ^ (nFileIndexHigh >>> 32)) +

               (int)(nFileIndexLow ^ (nFileIndexHigh >>> 32));

    }

    public boolean equals(Object obj) {

        if (obj == this)

            return true;

        if (!(obj instanceof FileKey))

            return false;

        FileKey other = (FileKey)obj;

        if ((this.dwVolumeSerialNumber != other.dwVolumeSerialNumber) ||

            (this.nFileIndexHigh != other.nFileIndexHigh) ||

            (this.nFileIndexLow != other.nFileIndexLow)) {

            return false;

        }

        return true;

    }

    private native void init(FileDescriptor fd) throws IOException;

    private static native void initIDs();

    static {

        initIDs();

    }

}