geometry.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 120 行

/*
 * $Id: Geometry.java,v 1.2 2003/11/29 17:20:24 gbin Exp $
 */
package org.jnode.fs.util;

/**
 * @author epr
 */
public class Geometry {

	private final int cylinders;
	private final int heads;
	private final int sectors;

	/**
	 * Create a new instance
	 * 
	 * @param c
	 *           The number of cylinders
	 * @param h
	 *           The number of heads
	 * @param s
	 *           The number of sectors/cylinder
	 */
	public Geometry(int c, int h, int s) {
		this.cylinders = c;
		this.heads = h;
		this.sectors = s;
	}

	/**
	 * @return int
	 */
	public int getCylinders() {
		return cylinders;
	}

	/**
	 * @return int
	 */
	public int getHeads() {
		return heads;
	}

	/**
	 * @return int
	 */
	public int getSectors() {
		return sectors;
	}

	/**
	 * Gets the total number of sectors
	 * 
	 * @return int
	 */
	public long getTotalSectors() {
		long v = cylinders;
		v *= heads;
		v *= sectors;
		return v;
	}

	/**
	 * Gets the logical sector number for a given CHS.
	 * 
	 * @param chs
	 * @return long
	 */
	public long getLogicalSector(CHS chs) {
		//ls = c*H*S + h*S + s - 1
		long v = chs.getCylinder() * heads * sectors;
		v += chs.getHead() * sectors;
		v += chs.getSector();
		return v - 1;
	}

	/**
	 * Gets a CHS from a given logical sector number
	 * 
	 * @param logicalSector
	 * @return CHS
	 */
	public CHS getCHS(long logicalSector) {
		// ls = (c*H + h) * S + s - 1

		long v = logicalSector;
		int s = (int) ((v % sectors) + 1);
		v = v / sectors;
		int h = (int) (v % heads);
		v = v / heads;
		int c = (int)v;

		return new CHS(c, h, s);
	}

	public CHS NextSector(CHS chsToIncrement) {

		int s = chsToIncrement.getSector();
		int h = chsToIncrement.getHead();
		int c = chsToIncrement.getCylinder();

		s++;

		if (s > sectors) {
			s = 1;
			h++;
			if (h >= heads) {
				h = 0;
				c++;
				if (c >= cylinders) {
					throw new IllegalArgumentException("this geometry doesn't support cyclinder" + c);
				}
			}
		}
		return new CHS(c, h, s);
	}

}