/*

 * $Id$

 *

 * Copyright (C) 2003-2009 JNode.org

 *

 * This library is free software; you can redistribute it and/or modify it

 * under the terms of the GNU Lesser General Public License as published

 * by the Free Software Foundation; either version 2.1 of the License, or

 * (at your option) any later version.

 *

 * This library 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 Lesser General Public 

 * License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public License

 * along with this library; If not, write to the Free Software Foundation, Inc., 

 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

 */

package org.jnode.vm;

import org.jnode.system.IOResource;

import org.jnode.system.Resource;

import org.jnode.system.ResourceNotFreeException;

import org.jnode.system.ResourceOwner;

import org.jnode.util.NumberUtils;

/**

 * Default implementation of IOResource.

 *

 * @author Ewout Prangsma (epr@users.sourceforge.net)

 */

final class IOResourceImpl extends Region implements IOResource {

    /**

     * The first port of this resource

     */

    private int startPort;

    /**

     * The length of the port region

     */

    private int length;

    /**

     * Has this resource been released?

     */

    private boolean released;

    /**

     * The list of active IOResource's

     */

    private static Region resources;

    /**

     * Create a new instance

     *

     * @param owner

     * @param startPort

     * @param length

     */

    private IOResourceImpl(ResourceOwner owner, int startPort, int length) {

        super(owner);

        this.startPort = startPort;

        this.length = length;

        this.released = false;

    }

    /**

     * Claim a range of IO ports

     *

     * @param owner

     * @param startPort

     * @param length

     * @return The claimed resource

     * @throws ResourceNotFreeException

     */

    protected static synchronized IOResource claimIOResource(ResourceOwner owner, int startPort, int length)

        throws ResourceNotFreeException {

        final IOResourceImpl res = new IOResourceImpl(owner, startPort, length);

        if (isFree(resources, res)) {

            resources = add(resources, res);

            return res;

        } else {

            final Object curOwner = get(resources, res).getOwner();

            throw new ResourceNotFreeException("port " + NumberUtils.hex(startPort) + "-" +

                NumberUtils.hex(startPort + length - 1) + " is owned by " + curOwner);

        }

    }

    /**

     * Returns the length.

     *

     * @return int

     */

    public int getLength() {

        return length;

    }

    /**

     * Returns the startPort.

     *

     * @return int

     */

    public int getStartPort() {

        return startPort;

    }

    public int inPortByte(int portNr) {

        testPort(portNr, 1);

        return Unsafe.inPortByte(portNr);

    }

    public int inPortWord(int portNr) {

        testPort(portNr, 2);

        return Unsafe.inPortWord(portNr);

    }

    public int inPortDword(int portNr) {

        testPort(portNr, 4);

        return Unsafe.inPortDword(portNr);

    }

    public void outPortByte(int portNr, int value) {

        testPort(portNr, 1);

        Unsafe.outPortByte(portNr, value);

    }

    public void outPortWord(int portNr, int value) {

        testPort(portNr, 2);

        Unsafe.outPortWord(portNr, value);

    }

    public void outPortDword(int portNr, int value) {

        testPort(portNr, 4);

        Unsafe.outPortDword(portNr, value);

    }

    /**

     * Compare to regions.

     *

     * @param otherRegion

     * @return a negative integer, zero, or a positive integer as

     *         this object is less than, equal to, or greater than the

     *         specified region. If the regions overlap, 0 is returned.

     */

    public int compareTo(Region otherRegion) {

        final IOResourceImpl other = (IOResourceImpl) otherRegion;

        if (this.startPort + this.length <= other.startPort) {

            return -1;

        } else if (this.startPort >= other.startPort + other.length) {

            return 1;

        } else {

            return 0;

        }

    }

    /**

     * Give up this resource. After this method has been called, the resource

     * cannot be used anymore.

     */

    public void release() {

        if (!this.released) {

            this.released = true;

            synchronized (getClass()) {

                resources = remove(resources, this);

            }

        }

    }

    /**

     * Gets the parent resource if any.

     *

     * @return The parent resource, or null if this resource has no parent.

     */

    public Resource getParent() {

        return null;

    }

    private void testPort(int portNr, int size) {

        if (released) {

            throw new IndexOutOfBoundsException("Resource is released");

        }

        if ((portNr < startPort) || ((portNr + size) > (startPort + length))) {

            throw new IndexOutOfBoundsException();

        }

    }

}