inode.java

一个简单的操作系统模拟程序 java+swing 可进行一般的文件操作 进程建立及删除等

/*
 * INode.java,ver0.1.0
 *
 * Created on 2006年11月30日, 下午6:45
 *
 *This Class abstracted the i-Node for the file system
 *
 *History: 2006年11月30日,ver 0.1.0 first release
 */

package ossimulation;
import java.util.*;


/**
 *
 * @author Decell.Chou
 */
public class INode {
    private char[] name;//the name of the i node
    private char extName;//the extended name of the i node
    private int fileLength;//the length of the file
    private char[] iNode;//the entity of the i node
    private int fileDescriptor;//the file descriptor,actually is the index of the block of the inode
    private int index;//the index of the data field of the i node
    Disk simDisk;//the simulation disk
    
    /** Creates a new instance of INode */
    public INode(String argName,Disk argDisk) {
        //creat a -inode
        name = new char[10];
        iNode = new char[64];
        simDisk = argDisk;
        fileDescriptor = -1;
        index = 12;
        
        argName.getChars(0,argName.length(),name,0);//deal with the i-node name
        extName = 'd';//set the default extends name as d,indicate the the inode is a directory
        fileLength = 0;//set the default file length as zero.
        //initialized the inode entity
        for(int i = 0;i <= 63;i++){
            iNode[i] = 0;
        }
        
        //copy the name to the inode entity 
        for(int i = 0;i <= 9;i++){
            iNode[i] = name[i];
        }
        iNode[10] = extName;//copy the extended name to the inode entity
        iNode[11] = (char)fileLength;//copy the file length to the inode entity
        
        //requst free space in the disk,write the inode entity into it;
        writeToDisk(iNode);
    }
    
    /**used to write contend to the disk,the content must de char[64]*/
    private void writeToDisk(char[] content){
       
        //if the fd is null, then allocate new space to the inode
        if(fileDescriptor == -1){
            fileDescriptor = simDisk.findNextFree();
        }
        simDisk.eraseBlock(fileDescriptor);
        simDisk.writeBlock(content,fileDescriptor);
    }
    
    /**used to increase the length of the file */
    private void increaseLength(){
        //increase the length of the file
        fileLength++;
        iNode[11] = (char)fileLength;
        //update the disk content
        this.writeToDisk(iNode);
    }
    
    /**the the fileDesciptor of the inode*/
    public int getFileDescriptor(){
        return fileDescriptor;
    }
    
    /**get the inode name*/
    public String getName(){
        String nameString;
        nameString = String.copyValueOf(name);
        return nameString;
     }
    
    /**get the file length*/
    public int getFileLength(){
        return(fileLength);
    }
    
    /**set the inode name*/
    public void setName(String argName){
        for(int i = 0;i <= 9;i++){
            name[i] = 0;
        }
        
        argName.getChars(0,argName.length(),name,0);
        
        for(int i = 0;i <= 9;i++){
            iNode[i] = name[i];
        }
        writeToDisk(iNode);
    }
    
    /**get the ExtName of the inode*/
    public char getExtName(){
        return extName;
    }
    
    /**set the ExtName of the inode*/
    public void setExtName(char argExtName){
        extName = argExtName;
        iNode[10] = argExtName;
        writeToDisk(iNode);
    }

    /**add content to the data field of the i node*/
    public void addPointer(int argFileDescriptor){
        int i;
        char fd = (char)argFileDescriptor;
        //search for the space 
        for(i = 12;i <= 63 && iNode[i] != 0;i++);
        iNode[i] = fd;
        //if there is no space in the data field of the i node, then allocate a new space to it
        if(i == index){
            index ++;//increase the data field index
        }
        writeToDisk(iNode);
    }
    
    /**delete a pointer from the data field of the i node*/
    public void delPointer(int argFileDescriptor){
        int i;
        char fd = (char)argFileDescriptor;
        //search for the propriety i node pointer
        for( i = 12;i <= 63;i++){
            if(iNode[i] == fd){
                break;
            }
        }
        //clear the corresponding bit
        iNode[i] = 0;
    
        writeToDisk(iNode);
    }
    
    /**destroy the i node*/
    public void destroy(int argFileDescriptor){
        char[] targetBlock = simDisk.readBlock(argFileDescriptor);
        if(targetBlock[10] == 'd'){
            for(int i = 12;i <= 63;i++){
                if(targetBlock[i] == 0){
                    continue;
                }
                destroy((int)targetBlock[i]);
            }
        } else{
            for(int i = 12;targetBlock[i] != 0;i++){
                simDisk.eraseBlock((int)targetBlock[i]);
            }
        }
        simDisk.eraseBlock(argFileDescriptor);
    }
    
    /**Edit the file content sepcify by the i node*/
    public void addContent(ArrayList newContent){
        Iterator contentsIterator = newContent.iterator();//the iterator interface,used to get contents from the ArrayList
        int fd;//the file descriptor;
        char[] lineContent = new char[64];
        String tmpContent;
        
        for(;contentsIterator.hasNext();){
           //write the content to the disk
            tmpContent = (String)contentsIterator.next();
            fd = simDisk.findNextFree();
            //clear the previous line content
            for(int i = 0;i <= 63;i++){
                lineContent[i] = 0;
            }
            tmpContent.getChars(0,tmpContent.length(),lineContent,0);
            simDisk.writeBlock(lineContent,fd);
            //add the file descriptor to the data field of the i node
            this.addPointer(fd);
            //update the length of the file
            this.increaseLength();
        }
    }
   
    
    /**read the content from the inode */
    public ArrayList readContent(){
        ArrayList contentList = new ArrayList();
        char[] content = new char[64];
        
        for(int i = 0 ;i < this.getFileLength();i++){
            contentList.add(String.copyValueOf(simDisk.readBlock((char)iNode[12 + i])));
        }
        return contentList;
    }
    
    /**The  toString method */
    public String toString(){
        int nameLength;
        for(nameLength = 0;(nameLength < name.length) && name[nameLength] != 0;nameLength++);
        return String.copyValueOf(name,0,nameLength);
    }
    
    /**Existed only for Class Debuging*/
    static public void main(String[] args){
        Disk simDisk = new Disk();
        INode iNode1 = new INode("t inode 1",simDisk);
        System.out.println(iNode1.getFileDescriptor());//target is 2
        
        //the the construction methoe of the Class
        System.out.println(iNode1.getFileDescriptor());//target is 2
        System.out.println(String.copyValueOf(simDisk.readBlock(iNode1.getFileDescriptor())));
        
        //test the getName and the setName method
        iNode1.setName("ssdf");
        System.out.println(iNode1.getName());//target is ssdf
        System.out.println(iNode1.getFileDescriptor());//target is 2

        //test the add and del pointer method
        for(int i = 12;i <= 50;i++){
            iNode1.addPointer(i);
        }
        iNode1.delPointer(24);
        iNode1.delPointer(50);
        iNode1.delPointer(12);
        for(int i = 120;i <= 127;i++){
            iNode1.addPointer(i);
        }
        
        //test the destroy method
        iNode1.delPointer(44);
        iNode1.destroy(iNode1.getFileDescriptor());
        System.out.println(iNode1.getFileDescriptor());
        System.out.println(String.copyValueOf(simDisk.readBlock(iNode1.getFileDescriptor())));
        
        //test the editContent method
        INode iNode2 = new INode("t inode 2",simDisk);
        iNode2.setExtName('e');
        ArrayList contentList = new ArrayList();
        //print the inode imformation
        System.out.println(String.copyValueOf(simDisk.readBlock(iNode2.getFileDescriptor())));
        //add content
        contentList.add("asdasd");
        contentList.add("sdjhfjsgdjf");
        contentList.add("sjdjsdgfjsdgfkajdhsgfkajdsf");
        contentList.add("asasdas");
        contentList.add("");
        contentList.add("x++");
        iNode2.addContent(contentList);
        
        char[] content = new char[64];
        content = simDisk.readBlock(iNode2.getFileDescriptor());
        char[] fileContent;
        for(int i = 12; i <= 63;i++){
            fileContent = simDisk.readBlock((int)content[i]);
            System.out.println(String.copyValueOf(fileContent));
        }
        System.out.println(iNode2.getFileLength());
    
        //test the readContent method
        ArrayList inodeContent = iNode2.readContent();
        Iterator contentIterator = inodeContent.iterator();
        for(;contentIterator.hasNext();){
            System.out.println(contentIterator.next());
        }
        
        //test the toString method
        System.out.println(iNode2.toString());
    }

}