ULONGLONG *GetFileClusters(
                    PCHAR lpFileName,
                    ULONG ClusterSize, 
                    ULONG *ClCount,
                    ULONG *FileSize 
                    )
{
    HANDLE  hFile;
    ULONG   OutSize;
    ULONG   Bytes, Cls, CnCount, r;
    ULONGLONG *Clusters = NULL;
    BOOLEAN Result = FALSE;
    LARGE_INTEGER PrevVCN, Lcn;
    STARTING_VCN_INPUT_BUFFER  InBuf;
    PRETRIEVAL_POINTERS_BUFFER OutBuf;

    hFile = CreateFile(lpFileName, FILE_READ_ATTRIBUTES,
                       FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
                       NULL, OPEN_EXISTING, 0, 0);

    if (hFile != INVALID_HANDLE_VALUE)
    {
        *FileSize = GetFileSize(hFile, NULL);

        OutSize = sizeof(RETRIEVAL_POINTERS_BUFFER) + (*FileSize / ClusterSize) * sizeof(OutBuf->Extents);

        OutBuf = malloc(OutSize);

        InBuf.StartingVcn.QuadPart = 0;
		
        if (DeviceIoControl(hFile, FSCTL_GET_RETRIEVAL_POINTERS, &InBuf, 
                            sizeof(InBuf), OutBuf, OutSize, &Bytes, NULL))
        {
            *ClCount = (*FileSize + ClusterSize - 1) / ClusterSize;

            Clusters = malloc(*ClCount * sizeof(ULONGLONG));

            PrevVCN = OutBuf->StartingVcn;

            for (r = 0, Cls = 0; r < OutBuf->ExtentCount; r++)
            {
                Lcn = OutBuf->Extents[r].Lcn;

                for (CnCount = OutBuf->Extents[r].NextVcn.QuadPart - PrevVCN.QuadPart;
                     CnCount; CnCount--, Cls++, Lcn.QuadPart++) Clusters[Cls] = Lcn.QuadPart;

                PrevVCN = OutBuf->Extents[r].NextVcn;
            }
        }
			
        free(OutBuf);	

        CloseHandle(hFile);
    }
    return Clusters;