framelist.java

来自「纯java操作系统jnode,安装简单和操作简单的个人使用的Java操作系统」· Java 代码 · 共 86 行

/*
 * $Id: FrameList.java,v 1.1 2003/11/25 11:42:17 epr Exp $
 */
package org.jnode.driver.usb.uhci;

import org.jnode.system.ResourceManager;

/**
 * @author Ewout Prangsma ([e-mail])
 */
public class FrameList extends AbstractStructure {

	/** Shadow list */
	private final AbstractStructure[] list = new AbstractStructure[1024];

	/**
	 * Create a new instance
	 * 
	 * @param rm
	 */
	public FrameList(ResourceManager rm) {
		super(rm, 4096, 4096);
		for (int i = 0; i < 1024; i++) {
			setListPointerInvalid(i);
		}
	}

	/**
	 * Set the list pointer to the given transfer descriptor.
	 * 
	 * @param frame
	 *            The framenumber 0..1023
	 * @param td
	 */
	public final void setListPointer(int frame, TransferDescriptor td) {
		final int ptr = td.getDescriptorAddress() & 0xFFFFFFF0;
		this.list[frame] = td;
		setInt(frame << 2, ptr);
	}

	/**
	 * Set the list pointer to the given queue head.
	 * 
	 * @param frame
	 *            The framenumber 0..1023
	 * @param qh
	 * @param depthFirst
	 *            If true, the next queue is processed depth first, otherwise the next queue is
	 *            processed breadth first
	 */
	public final void setListPointer(int frame, QueueHead qh, boolean depthFirst) {
		final int ptr = (qh.getDescriptorAddress() & 0xFFFFFFF0) | 0x2 | (depthFirst ? 0x4 : 0x0);
		this.list[frame] = qh;
		setInt(frame << 2, ptr);
	}

	/**
	 * Set the list pointer as invalid
	 * 
	 * @param frame
	 *            The framenumber 0..1023
	 */
	public final void setListPointerInvalid(int frame) {
		setInt(frame << 2, 0);
		this.list[frame] = null;
	}

	/**
	 * Get the list pointer at a given frame
	 * 
	 * @param frame
	 *            The framenumber 0..1023
	 * @return A TransferDescriptor, a QueueHead or null.
	 */
	public final AbstractStructure getListPointer(int frame) {
		return this.list[frame];
	}
	
	/**
	 * Gets the number of elements in this list.
	 */
	public final int getSize() {
		return 1024;
	}
}