// ECE3055, Spring 2003
// File System Implementation, Lab Assignment
// Definitions
// George F. Riley

import java.io.*;

class filesys {
  // Declare class for Open File table here
    // Definitions 
    // Max length of file name
    public static final int MAX_FILE_NAME =   8;
    // We only track 128 total files
    public static final int MAX_FILES     = 128;
    // We only have 10 open files at once
    public static final int MAX_FILESOPEN =  10;

    // You will likely need some static variables to represent
    // the Directory,  FAT, and OpenFile table.

    // Static data
    private static int[] FAT = new int[FAT_SIZE_INT];    // The FAT Table
    private static dirent[] DIR = new dirent[MAX_FILES]; // The directory
  //private static OpenFile[] files = new OpenFile[MAX_FILESOPEN];
    private static int FAT_UNLINKED = 0xffffffff;        // Unlinked FAT entry

    // Private static functions
    // FAT Helpers
    private static int LoadFAT() throws IOException
    {
        byte f[] = new byte[NUMBER_CLUSTERS * 4]; // Each FAT entry four bytes
        physical.ReadData(f, 0, FAT_SECTORS);
        ByteArrayInputStream bi = new ByteArrayInputStream(f);
        DataInputStream di = new DataInputStream(bi);
        int i;
        for (i = 0; i < NUMBER_CLUSTERS; ++i)
            {
                FAT[i] = di.readInt();
            }
        return 0;
    }

    private static int StoreFAT() throws IOException
    {
        ByteArrayOutputStream bo = new ByteArrayOutputStream();
        DataOutputStream dos = new DataOutputStream(bo);
        int i;
        for (i = 0; i < NUMBER_CLUSTERS; ++i)
            {
                dos.writeInt(FAT[i]);
            }
        byte f[] = bo.toByteArray();
        physical.WriteData(f, 0, FAT_SECTORS);
        return 0;
    }

    // Directory Helpers
    private static int LoadDIR() throws IOException
    {
        byte f[] = new byte[DIR_BYTES];
        physical.ReadData(f, 0, DIR_SECTORS);
        ByteArrayInputStream bi = new ByteArrayInputStream(f);
        DataInputStream di = new DataInputStream(bi);
        for (int i = 0; i < MAX_FILES; ++i)
            {
                //System.out.println("NewDirent " + i + " maxf " + MAX_FILES);
                //System.out.println("available " + bi.available());
                DIR[i] = new dirent();
                try { DIR[i].readExternal(di); } catch (Exception e) { }
            }
        return 0;
    }

    private static int StoreDIR() throws IOException
    {
        ByteArrayOutputStream bo = new ByteArrayOutputStream();
        DataOutputStream dos = new DataOutputStream(bo);
        for (int i = 0; i < MAX_FILES; ++i)
            {
                //System.out.println("StoreDir " + i);
                DIR[i].writeExternal(dos);
            }
        byte f[] = bo.toByteArray();
        physical.WriteData(f, FAT_SECTORS, DIR_SECTORS);
        return 0;
    }