/// <summary><see cref="http://msdn.microsoft.com/en-us/library/windows/desktop/dd405526(v=vs.85).aspx"/></summary>
/// <remarks>
/// Does not correcly handle all cases of this method!. Especially regarding compressed/encrypted and/or sparse files in NTFS.
/// Consider yourself warned.
/// </remarks>
public FileExtentInfo[] FileSystemGetRetrievalPointers()
{
STARTING_VCN_INPUT_BUFFER input = new STARTING_VCN_INPUT_BUFFER();
input.StartingVcn = 0;
List <FileExtentInfo> extents = new List <FileExtentInfo>();
uint chunkSize = 1024;
uint singleExtentSize = MarshalHelper.SizeOf <RETRIEVAL_POINTERS_EXTENT>();
int lastError;
do
{
byte[] data = DeviceIoControlHelper.InvokeIoControl(Handle, IOControlCode.FsctlGetRetrievalPointers, chunkSize, input, out lastError);
RETRIEVAL_POINTERS_BUFFER output = new RETRIEVAL_POINTERS_BUFFER();
output.ExtentCount = BitConverter.ToUInt32(data, 0);
output.StartingVcn = BitConverter.ToUInt64(data, sizeof(ulong));
output.Extents = new RETRIEVAL_POINTERS_EXTENT[output.ExtentCount];
// Parse extents
int extentsSize = (int)(output.ExtentCount * singleExtentSize);
using (var dataPtr = new UnmanagedMemory(extentsSize))
{
Marshal.Copy(data, sizeof(ulong) + sizeof(ulong), dataPtr, extentsSize);
for (ulong i = 0; i < output.ExtentCount; i++)
{
IntPtr currentPtr = new IntPtr(dataPtr.Handle.ToInt64() + (int)(singleExtentSize * i));
output.Extents[i] = currentPtr.ToStructure <RETRIEVAL_POINTERS_EXTENT>();
}
}
// Make extents more readable
for (ulong i = 0; i < output.ExtentCount; i++)
{
ulong startVcn = i == 0
? output.StartingVcn
: output.Extents[i - 1].NextVcn;
ulong size = output.Extents[i].NextVcn - startVcn;
FileExtentInfo extent = new FileExtentInfo();
extent.Size = size;
extent.Vcn = startVcn;
extent.Lcn = output.Extents[i].Lcn;
extents.Add(extent);
}
if (lastError == 38)
{
// End of file reached
break;
}
// Prep the start point for the next call
input.StartingVcn = output.Extents[output.ExtentCount - 1].NextVcn;
} while (lastError == 234);
return(extents.ToArray());
}
private void button1_Click(object sender, EventArgs e)
{
textBox1.Text = "";
totalClusters = 0;
int extentNumber = 1;
label4.Text = "File fragmentation factor = ";
if (path.Length == 0 || !File.Exists(path))
{
MessageBox.Show("Select a file!", "Information", MessageBoxButtons.OK, MessageBoxIcon.Information);
return;
}
textBox1.Text += "Analysis...";
using (var file = File.Open(path, FileMode.Open, FileAccess.Read, FileShare.Read))
{
var vcnIn = new STARTING_VCN_INPUT_BUFFER();
var rpb = new RETRIEVAL_POINTERS_BUFFER();
int bytesReturned = 0;
int err = 0;
vcnIn.StartingVcn = 0L;
do
{
DeviceIoControl(
file.SafeFileHandle, FSCTL_GET_RETRIEVAL_POINTERS,
&vcnIn, STARTING_VCN_INPUT_BUFFER.Size,
&rpb, RETRIEVAL_POINTERS_BUFFER.Size,
&bytesReturned, null
);
err = Marshal.GetLastWin32Error();
switch (err)
{
case 38: // ERROR_HANDLE_EOF
if (extentNumber == 1)
{
textBox1.Text += "MFT Table...";
}
else
{
textBox1.Text += $"\r\nTotal clusters: {totalClusters} \r\nFragments: {(extentNumber - 1)}";
}
break;
case 0: // NO_ERROR
textBox1.Text += $"\r\nFragment #{extentNumber}";
textBox1.Text += $"\r\n\tStart cluster: {rpb.Lcn}\r\n\tLength: {rpb.NextVcn - rpb.StartingVcn} clusters";
totalClusters += rpb.NextVcn - rpb.StartingVcn;
textBox1.Text += $"\r\nTotal clusters: {totalClusters}\r\nFragments:{extentNumber}";
break;
case 234: // ERROR_MORE_DATA
textBox1.Text += $"\r\nFragment #{extentNumber++}";
textBox1.Text += $"\r\n\tStart cluster: {rpb.Lcn}\r\n\tLength: {rpb.NextVcn - rpb.StartingVcn} clusters";
totalClusters += rpb.NextVcn - rpb.StartingVcn;
vcnIn.StartingVcn = rpb.NextVcn;
break;
}
} while (err == 234);
}
if (extentNumber - 1 == 0)
{
textBox1.Text += $"\r\nFile fragmentation factor = 0%";
label4.Text += $"0%";
}
else
{
double coeffragment = (double)(extentNumber - 1) / totalClusters * 100;
textBox1.Text += $"\r\nFile fragmentation factor = {coeffragment:0.####} %";
label4.Text += $"{coeffragment:0.######}%";
}
}
