usbpacket.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 158 行

/*
 * $Id: USBPacket.java,v 1.1 2003/11/25 11:41:20 epr Exp $
 */
package org.jnode.driver.usb;

import org.jnode.util.NumberUtils;

/**
 * @author Ewout Prangsma ([e-mail])
 */
public class USBPacket implements USBConstants {

	private final byte[] data;
	private final int size;
	private final int offset;

	/**
	 * Create a new instance
	 * 
	 * @param size
	 */
	public USBPacket(int size) {
		this.data = new byte[size];
		this.size = size;
		this.offset = 0;
	}

	/**
	 * Create a new instance
	 * 
	 * @param data
	 */
	public USBPacket(byte[] data) {
		this(data, 0, data.length);
	}

	/**
	 * Create a new instance
	 * 
	 * @param data
	 * @param ofs
	 * @param len
	 */
	public USBPacket(byte[] data, int ofs, int len) {
		this.data = data;
		this.size = len;
		this.offset = ofs;
	}

	/**
	 * Set a 8-bit byte at the given offset
	 * 
	 * @param ofs
	 * @param value
	 */
	protected final void setByte(int ofs, int value) {
		data[this.offset + ofs] = (byte) value;
	}

	/**
	 * Set a 16-bit short at the given offset
	 * 
	 * @param ofs
	 * @param value
	 */
	protected final void setShort(int ofs, int value) {
		data[this.offset + ofs + 0] = (byte) (value & 0xFF);
		data[this.offset + ofs + 1] = (byte) ((value >> 8) & 0xFF);
	}

	/**
	 * Set a 32-bit int at the given offset
	 * 
	 * @param ofs
	 * @param value
	 */
	protected final void setInt(int ofs, int value) {
		data[this.offset + ofs + 0] = (byte) (value & 0xFF);
		data[this.offset + ofs + 1] = (byte) ((value >> 8) & 0xFF);
		data[this.offset + ofs + 2] = (byte) ((value >> 16) & 0xFF);
		data[this.offset + ofs + 3] = (byte) ((value >>> 24) & 0xFF);
	}

	/**
	 * Get a 8-bit byte at the given offset
	 * 
	 * @param ofs
	 */
	protected final int getByte(int ofs) {
		return data[this.offset + ofs] & 0xFF;
	}

	/**
	 * Get a 16-bit short at the given offset
	 * 
	 * @param ofs
	 */
	protected final int getShort(int ofs) {
		final int v0 = data[this.offset + ofs + 0] & 0xFF;
		final int v1 = data[this.offset + ofs + 1] & 0xFF;
		return (short) (v0 | (v1 << 8));
	}

	/**
	 * Get a 16-bit char at the given offset
	 * 
	 * @param ofs
	 */
	protected final char getChar(int ofs) {
		final int v0 = data[this.offset + ofs + 0] & 0xFF;
		final int v1 = data[this.offset + ofs + 1] & 0xFF;
		return (char) (v0 | (v1 << 8));
	}

	/**
	 * Get a 32-bit int at the given offset
	 * 
	 * @param ofs
	 */
	protected final int getInt(int ofs) {
		final int v0 = data[this.offset + ofs + 0] & 0xFF;
		final int v1 = data[this.offset + ofs + 1] & 0xFF;
		final int v2 = data[this.offset + ofs + 2] & 0xFF;
		final int v3 = data[this.offset + ofs + 3] & 0xFF;
		return (short) (v0 | (v1 << 8) | (v2 << 16) | (v3 << 24));
	}

	/**
	 * Gets the data itself
	 */
	public byte[] getData() {
		return this.data;
	}

	/**
	 * Gets the offset within the data
	 */
	public int getOffset() {
		return this.offset;
	}

	/**
	 * Gets the length of the data
	 */
	public int getSize() {
		return this.size;
	}

	/**
	 * Convert to a String representation.
	 * 
	 * @see java.lang.Object#toString()
	 */
	public String toString() {
		return NumberUtils.hex(data, offset, size);
	}
}