public override void EraseFileSystemObject(StreamInfo info, ErasureMethod method,
ErasureMethodProgressFunction callback)
{
VolumeInfo volume = VolumeInfo.FromMountpoint(info.DirectoryName);
if (info.Length < Math.Max(volume.ClusterSize, 1024))
{
using (FileStream strm = info.Open(FileMode.Open, FileAccess.Write,
FileShare.None))
{
method.Erase(strm, long.MaxValue,
PrngManager.GetInstance(ManagerLibrary.Settings.ActivePrng), null);
}
}
long fileArea = GetFileArea(info.FullName);
if (fileArea == 0)
return;
using (FileStream strm = info.Open(FileMode.Open, FileAccess.Write,
FileShare.None, FileOptions.WriteThrough))
{
strm.SetLength(fileArea);
method.Erase(strm, long.MaxValue,
PrngManager.GetInstance(ManagerLibrary.Settings.ActivePrng),
callback
);
strm.Seek(0, SeekOrigin.Begin);
strm.SetLength(0);
}
}
private void EraseFileClusterTips(string file, ErasureMethod method)
{
StreamInfo streamInfo = new StreamInfo(file);
DateTime lastAccess = streamInfo.LastAccessTime;
DateTime lastWrite = streamInfo.LastWriteTime;
DateTime created = streamInfo.CreationTime;
long fileArea = GetFileArea(file);
long fileLength = streamInfo.Length;
if (fileArea == fileLength)
return;
using (FileStream stream = streamInfo.Open(FileMode.Open, FileAccess.Write,
FileShare.None, FileOptions.WriteThrough))
{
try
{
stream.SetLength(fileArea);
stream.Seek(fileLength, SeekOrigin.Begin);
method.Erase(stream, long.MaxValue, PrngManager.GetInstance(
ManagerLibrary.Settings.ActivePrng), null);
}
finally
{
stream.SetLength(fileLength);
streamInfo.LastAccessTime = lastAccess;
streamInfo.LastWriteTime = lastWrite;
streamInfo.CreationTime = created;
}
}
}
public override void EraseOldFileSystemResidentFiles(VolumeInfo volume,
DirectoryInfo tempDirectory, ErasureMethod method,
FileSystemEntriesEraseProgress callback)
{
try
{
long oldMFTSize = NtfsApi.GetMftValidSize(volume);
for (; ; )
{
using (FileStream strm = new FileStream(
GenerateRandomFileName(tempDirectory, 18), FileMode.CreateNew,
FileAccess.Write, FileShare.None, 8, FileOptions.WriteThrough))
{
long streamSize = 0;
try
{
while (true)
{
strm.SetLength(++streamSize);
method.Erase(strm, long.MaxValue,
PrngManager.GetInstance(ManagerLibrary.Settings.ActivePrng),
null);
}
}
catch (IOException)
{
if (streamSize == 1)
return;
}
}
if (NtfsApi.GetMftValidSize(volume) > oldMFTSize)
break;
}
}
catch (IOException)
{
}
}
public override void EraseFileSystemObject(StreamInfo info, ErasureMethod method,
ErasureMethodProgressFunction callback)
{
long fileArea = GetFileArea(info.FullName);
using (FileStream strm = info.Open(FileMode.Open, FileAccess.Write,
FileShare.None, FileOptions.WriteThrough))
{
strm.SetLength(fileArea);
if (strm.Length != 0)
{
method.Erase(strm, long.MaxValue,
PrngManager.GetInstance(ManagerLibrary.Settings.ActivePrng),
callback
);
}
strm.Seek(0, SeekOrigin.Begin);
strm.SetLength(0);
}
}
