System.Security.AccessControl.RawSecurityDescriptor.BinaryFormFromSddlForm C# (CSharp) Method

        private static byte[] BinaryFormFromSddlForm(string sddlForm)
        {
            if (sddlForm == null)
            {
                throw new ArgumentNullException(nameof(sddlForm));
            }
            Contract.EndContractBlock();

            int error;
            IntPtr byteArray = IntPtr.Zero;
            uint byteArraySize = 0;
            byte[] binaryForm = null;

            try
            {
                if (!Interop.Advapi32.ConvertStringSdToSd(
                        sddlForm,
                        GenericSecurityDescriptor.Revision,
                        out byteArray,
                        ref byteArraySize))
                {
                    error = Marshal.GetLastWin32Error();

                    if (error == Interop.Errors.ERROR_INVALID_PARAMETER ||
                        error == Interop.Errors.ERROR_INVALID_ACL ||
                        error == Interop.Errors.ERROR_INVALID_SECURITY_DESCR ||
                        error == Interop.Errors.ERROR_UNKNOWN_REVISION)
                    {
                        throw new ArgumentException(
                             SR.ArgumentException_InvalidSDSddlForm,
nameof(sddlForm));
                    }
                    else if (error == Interop.Errors.ERROR_NOT_ENOUGH_MEMORY)
                    {
                        throw new OutOfMemoryException();
                    }
                    else if (error == Interop.Errors.ERROR_INVALID_SID)
                    {
                        throw new ArgumentException(
                             SR.AccessControl_InvalidSidInSDDLString,
nameof(sddlForm));
                    }
                    else if (error != Interop.Errors.ERROR_SUCCESS)
                    {
                        Debug.Assert(false, string.Format(CultureInfo.InvariantCulture, "Unexpected error out of Win32.ConvertStringSdToSd: {0}", error));
                        // TODO : This should be a Win32Exception once that type is available
                        throw new Exception();
                    }
                }

                binaryForm = new byte[byteArraySize];

                //
                // Extract the data from the returned pointer
                //

                Marshal.Copy(byteArray, binaryForm, 0, (int)byteArraySize);
            }
            finally
            {
                //
                // Now is a good time to get rid of the returned pointer
                //
                if (byteArray != IntPtr.Zero)
                {
                    Interop.Kernel32.LocalFree(byteArray);
                }
            }

            return binaryForm;
        }

 public RawSecurityDescriptor(string sddlForm)
     : this(RawSecurityDescriptor.BinaryFormFromSddlForm(sddlForm), 0)
 {
 }