source: trunk/eraser6/Eraser.DefaultPlugins/FileSystems/Fat.cs @ 1210

/* 
 * $Id: Plugin.cs 1100 2009-06-03 02:49:33Z lowjoel $
 * Copyright 2008 The Eraser Project
 * Original Author: Joel Low <lowjoel@users.sourceforge.net>
 * Modified By:
 * 
 * This file is part of Eraser.
 * 
 * Eraser is free software: you can redistribute it and/or modify it under the
 * terms of the GNU General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later
 * version.
 * 
 * Eraser is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
 * A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 * 
 * A copy of the GNU General Public License can be found at
 * <http://www.gnu.org/licenses/>.
 */

using System;
using System.Collections.Generic;
using System.Text;

using System.IO;
using Eraser.Manager;
using Eraser.Util;

namespace Eraser.DefaultPlugins
{
    /// <summary>
    /// Provides functions to handle erasures specific to FAT volumes.
    /// </summary>
    public abstract class FatFileSystem : WindowsFileSystem
    {
        public override void EraseOldFileSystemResidentFiles(VolumeInfo volume,
            DirectoryInfo tempDirectory, ErasureMethod method,
            FileSystemEntriesEraseProgress callback)
        {
            //Nothing to be done here. FAT doesn't store files in its FAT.
        }

        public override void EraseFileSystemObject(StreamInfo info, ErasureMethod method,
            ErasureMethodProgressFunction callback)
        {
            //Create the file stream, and call the erasure method to write to
            //the stream.
            long fileArea = GetFileArea(info.FullName);
            using (FileStream strm = info.Open(FileMode.Open, FileAccess.Write,
                FileShare.None, FileOptions.WriteThrough))
            {
                //Set the end of the stream after the wrap-round the cluster size
                strm.SetLength(fileArea);

                //If the stream is empty, there's nothing to overwrite. Continue
                //to the next entry
                if (strm.Length != 0)
                {
                    //Then erase the file.
                    method.Erase(strm, long.MaxValue,
                        PrngManager.GetInstance(ManagerLibrary.Settings.ActivePrng),
                        callback
                    );
                }

                //Set the length of the file to 0.
                strm.Seek(0, SeekOrigin.Begin);
                strm.SetLength(0);
            }
        }

        protected override DateTime MinTimestamp
        {
            get
            {
                return new DateTime(1980, 1, 1, 0, 0, 0);
            }
        }
    }

    public class Fat32FileSystem : FatFileSystem
    {
        public override bool Supports(string fileSystemName)
        {
            if (fileSystemName == "FAT32")
                return true;
            return false;
        }

        public override void EraseDirectoryStructures(VolumeInfo info,
            FileSystemEntriesEraseProgress callback)
        {
            Fat32Api api = new Fat32Api(info);
        }
    }
}