C#

BobZscharnagk wrote:

error=5.

using (dd = new FileStream(path + ".dd", FileMode.Open, FileAccess.Write, FileShare.Write))
{
bool finished = NativeMethods.GetSparseRange(ldd.SafeFileHandle, query, ref response, 1024);

public static bool GetSparseRange(SafeFileHandle hdrive, in FILE_ALLOCATED_RANGE_BUFFER query, ref FILE_ALLOCATED_RANGE_BUFFER[] response, int count)
{
    int nInBufferSize = (int)Marshal.SizeOf(typeof(FILE_ALLOCATED_RANGE_BUFFER));
    IntPtr lpInBuffer = Marshal.AllocHGlobal(nInBufferSize);
    Marshal.StructureToPtr(query, lpInBuffer, true);
    uint bytesread=0;

    int nOutBufferSize = nInBufferSize * count;
    IntPtr lpOutBuffer = Marshal.AllocHGlobal(nOutBufferSize);

    //IntPtr[] ptrArr = new IntPtr[count];
    //for (int i = 0; i < count; ++i)
    //{
    //    ptrArr[i] = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(FILE_ALLOCATED_RANGE_BUFFER)));
    //    Marshal.StructureToPtr(response[i], ptrArr[i], true);
    //}
    bool rc = DeviceIoControl(
        hdrive,                                                     // device to be queried
        (uint)EIOControlCode.FsctlQueryAllocatedRanges,             // operation to perform
        lpInBuffer, (uint)nInBufferSize,                         // input buffer
        lpOutBuffer, (uint)nOutBufferSize,
        //ptrArr, (uint)(nInBufferSize * count),                   // output buffer
        ref bytesread,                                          // # bytes returned
        IntPtr.Zero);                                               // synchronous I/O
    // Get the last error and display it.
    int error = Marshal.GetLastWin32Error();
    Marshal.PtrToStructure(lpOutBuffer, response);
    //for (int j = 0; j < count / nInBufferSize; ++j)
    //{
    //    if (j < bytesread / nInBufferSize)
    //        Marshal.PtrToStructure(ptrArr[j], response[j]);
    //    Marshal.FreeHGlobal(ptrArr[j]);
    //}
    Marshal.FreeHGlobal(lpInBuffer);
    Marshal.FreeHGlobal(lpOutBuffer);
    return rc;
}

using System;
using Microsoft.Win32.SafeHandles;
using System.Runtime.InteropServices;
using System.Text;
using System.IO;
using System.Diagnostics;

namespace SparseRanges
{
    #region Structs

    struct FILE_ZERO_DATA_INFORMATION
    {
        public long offset;
        public long zero;
    }

    struct FILE_ALLOCATED_RANGE_BUFFER
    {
        public long offset;
        public long length;
    }
    #endregion

    class Program
    {
        #region Const ints
        const uint FSCTL_SET_SPARSE = 590020;
        const uint FSCTL_QUERY_ALLOCATED_RANGES = 606415;
        #endregion

        [DllImport("kernel32.dll", SetLastError = true)]
        extern static bool GetVolumeInformation(string vol, StringBuilder name, int nameSize, out uint serialNum, out uint maxNameLen, out uint flags, StringBuilder fileSysName, int fileSysNameSize);
        
        [DllImport("kernel32.dll", SetLastError = true)]
        static extern bool DeviceIoControl([In] SafeFileHandle hDevice, [In] uint dwIoControlCode, IntPtr lpInBuffer, [In] int nInBufferSize, IntPtr lpOutBuffer, [In] int nOutBufferSize, ref uint lpBytesReturned, [In] IntPtr lpOverlapped);
        public static bool GetSparseRange(SafeFileHandle hdrive, in FILE_ALLOCATED_RANGE_BUFFER query, ref FILE_ALLOCATED_RANGE_BUFFER[] response, int count)
        {
            int nInBufferSize = (int)Marshal.SizeOf(typeof(FILE_ALLOCATED_RANGE_BUFFER));
            IntPtr lpInBuffer = Marshal.AllocHGlobal(nInBufferSize);
            Marshal.StructureToPtr(query, lpInBuffer, true);

            int nOutBufferSize = nInBufferSize * count;
            IntPtr lpOutBuffer = Marshal.AllocHGlobal(nOutBufferSize);

            uint bytesread = 0;

            bool rc = DeviceIoControl(hdrive, FSCTL_QUERY_ALLOCATED_RANGES, lpInBuffer, nInBufferSize, lpOutBuffer, nOutBufferSize, ref bytesread, IntPtr.Zero);

            int error = Marshal.GetLastWin32Error();

            Marshal.FreeHGlobal(lpInBuffer);
            Marshal.FreeHGlobal(lpOutBuffer);
            return rc;
        }

        private static void PrintSparseRange(FILE_ALLOCATED_RANGE_BUFFER range)
        {
            Console.WriteLine("{0:d} offset, length = {1:d}", range.offset, range.length);
        }

        static void Main(string[] args)
        {
            uint temp1, temp2, flags, bytes=0;
            if (GetVolumeInformation("C:\\", null, 0, out temp1, out temp2, out flags, null, 0))
            {
                uint supports_sparse = flags & 0x40;
                if (supports_sparse == 0x40)
                {
                    Console.WriteLine("Volume supports sparse files...");
                    
                    string sparse_filename = Path.GetTempFileName();
                    System.IO.FileStream f = System.IO.File.Create(sparse_filename);

                    if (DeviceIoControl(f.SafeFileHandle, FSCTL_SET_SPARSE, IntPtr.Zero, 0, IntPtr.Zero, 0, ref bytes, IntPtr.Zero))
                    {
                        Console.WriteLine("Successfully generated a sparse file.");

                        f.SetLength(10240);

                        FILE_ALLOCATED_RANGE_BUFFER[] response = new FILE_ALLOCATED_RANGE_BUFFER[64];
                        FILE_ALLOCATED_RANGE_BUFFER query;
                        query.length = 10240;
                        query.offset = 0;
                        int count = 64;
                        
                        if(GetSparseRange(f.SafeFileHandle, query, ref response, count))
                        {
                            Action<FILE_ALLOCATED_RANGE_BUFFER> print_all = new Action<FILE_ALLOCATED_RANGE_BUFFER>(PrintSparseRange);
                            Array.ForEach(response, print_all);
                        }
                        f.Close();

                        Console.WriteLine("Removing temp sparse file.");
                        File.Delete(sparse_filename);
                    }
                }
            }
        }
    }
}

BobZscharnagk wrote:

The SafeFileHandle was created like this ...

using (dd = new FileStream(path + ".dd", FileMode.Open, FileAccess.Write, FileShare.Write))

f.SetLength(10240);

f.Write(new byte[] { (byte)'H', (byte)'e', (byte)'l', (byte)'l', (byte)'o' }, 0, 5);  //Added by Bob

int error = Marshal.GetLastWin32Error();

Marshal.PtrToStructure(lpOutBuffer, response);  //Added by Bob

Quote:

System.ArgumentException: 'The specified structure must be blittable or have layout information.

public static int GetSparseRange(SafeFileHandle hdrive, in FILE_ALLOCATED_RANGE_BUFFER query, ref FILE_ALLOCATED_RANGE_BUFFER[] response, out int count)
{
    int nInBufferSize = Marshal.SizeOf(typeof(FILE_ALLOCATED_RANGE_BUFFER));
    IntPtr lpInBuffer = Marshal.AllocHGlobal(nInBufferSize);
    Marshal.StructureToPtr(query, lpInBuffer, false);

    uint bytesreturned = 0, command = (uint)EIOControlCode.FsctlQueryAllocatedRanges;

    int nOutBufferSize = nInBufferSize * 1024;
    IntPtr lpOutBuffer = Marshal.AllocHGlobal(nOutBufferSize);
    DeviceIoControl(
        hdrive,                                                     // device to be queried
        (uint)command,                                              // operation to perform
        lpInBuffer, (uint)nInBufferSize,                            // input buffer
        lpOutBuffer, (uint)nOutBufferSize,
        //ptrArr, (uint)(nInBufferSize * count),                    // output buffer
        out bytesreturned,                                          // # bytes returned
        IntPtr.Zero);                                               // synchronous I/O
    // Get the last error and display it.
    int rc = Marshal.GetLastWin32Error();
    count = (int)bytesreturned / nInBufferSize;
    for (int j = 0; j < count; ++j)
    {
        response[j] = (FILE_ALLOCATED_RANGE_BUFFER)Marshal.PtrToStructure(lpOutBuffer + (j * nInBufferSize), typeof(FILE_ALLOCATED_RANGE_BUFFER));
    }
    Marshal.FreeHGlobal(lpInBuffer);
    Marshal.FreeHGlobal(lpOutBuffer);
    return rc;
}