with Interfaces;
package Agila_Ports is
   -- Original Open Agila implementation. Host identity values are supplied by
   -- trusted callers; a future syscall boundary must derive identity itself.
   subtype Word is Interfaces.Unsigned_32;
   Max_Ports : constant := 8;
   Queue_Capacity : constant := 4;
   type Status is (Ok, Invalid_Handle, Permission_Denied, Full, Empty,
                   Exhausted, Invalid_Argument);
   type Message is record
      Sender : Word := 0;
      Value : Word := 0;
   end record;
   type Manager is limited private;
   procedure Create (State : in out Manager; Owner : Word;
                     Handle : out Word; Result : out Status);
   procedure Allow_Sender (State : in out Manager; Handle, Owner, Sender : Word;
                           Result : out Status);
   procedure Revoke_Sender (State : in out Manager; Handle, Owner, Sender : Word;
                            Result : out Status);
   procedure Send (State : in out Manager; Handle, Caller, Value : Word;
                   Result : out Status);
   procedure Receive (State : in out Manager; Handle, Caller : Word;
                      Item : out Message; Result : out Status);
   procedure Close (State : in out Manager; Handle, Caller : Word;
                    Result : out Status);
private
   type Messages is array (Natural range 0 .. Queue_Capacity - 1) of Message;
   type Port is record
      Active : Boolean := False;
      Retired : Boolean := False;
      Generation : Word := 1;
      Owner : Word := 0;
      Allowed_Sender : Word := 0;
      Head : Natural range 0 .. Queue_Capacity - 1 := 0;
      Count : Natural range 0 .. Queue_Capacity := 0;
      Queue : Messages := [others => (0, 0)];
   end record;
   type Ports is array (Natural range 0 .. Max_Ports - 1) of Port;
   type Manager is limited record
      Table : Ports;
   end record;
end Agila_Ports;