Add NullFS

Signed-off-by: Thomas Heijligen <src@posteo.de>
diff --git a/src/filo-fs-nullfs.ads b/src/filo-fs-nullfs.ads
index 5f0bd5b..95b6d16 100644
--- a/src/filo-fs-nullfs.ads
+++ b/src/filo-fs-nullfs.ads
@@ -3,38 +3,15 @@
 with System;
 
 package FILO.FS.NullFS is
-   type NullFS_Type is private;
-
-
-   procedure Mount
-      (Item : in out NullFS_Type;
-       Success : out Boolean);
-
-   procedure Open
-      (Item    : in out NullFS_Type;
-       Path    : in     String;
-       Success : out    Boolean);
-
-   procedure Read
-      (Item    : in out NullFS_Type;
-       Buffer  : in out Buffer_Type;
-       Offset  : in     Natural;
-       Success : out    Boolean);
-
-   procedure Close 
-      (Item : in out NullFS_Type;
-       Success : out Boolean);
-
-   ---------------------------------------------------------------------
-
+   -- noop init
    function C_Mount return Interfaces.C.int
    with
       Export,
       Convention => C,
       External_Name => "nullfs_mount";
 
-   function C_Read 
-      (buf : System.Address;
+   function C_Read -- read from blockdev
+      (buf : System.Address; -- char*
        len : Interfaces.C.int)
    return Interfaces.C.int
    with
@@ -42,25 +19,12 @@
       Convention => C,
       External_Name => "nullfs_read";
 
-   function C_Dir
-      (Path : Interfaces.C.Strings.chars_ptr)
+   function C_Dir -- noop like open
+      (Path : System.Address) -- char*
    return Interfaces.C.int
    with
       Export,
       Convention => C,
       External_Name => "nullfs_dir";
 
-   function C_Close return Interfaces.C.int
-   with
-      Export,
-      Convention => C,
-      External_Name => "nullfs_close";
-
-private
-   type State_Type is (Unmounted, Mounted, File_Open);
-
-   type NullFS_Type is record
-      State : State_Type;
-   end record;
-   
 end FILO.FS.NullFS;