------------------------------------------------------------------------------
--                                                                          --
--                         GNAT RUNTIME COMPONENTS                          --
--                                                                          --
--         A D A . N U M E R I C S . D I S C R E T E _ R A N D O M          --
--                                                                          --
--                                 S p e c                                  --
--                                                                          --
--                            $Revision: 2 $                              --
--                                                                          --
-- This specification is adapted from the Ada Reference Manual for use with --
-- GNAT.  In accordance with the copyright of that document, you can freely --
-- copy and modify this specification,  provided that if you redistribute a --
-- modified version,  any changes that you have made are clearly indicated. --
--                                                                          --
------------------------------------------------------------------------------

generic
   type Result_Subtype is (<>);
package Ada.Numerics.Discrete_Random is

   --  Basic facilities.

   type Generator is limited private;

   function Random (Gen : Generator) return Result_Subtype;

   procedure Reset (Gen : Generator);
   procedure Reset (Gen : Generator; Initiator : Integer);

   --  Advanced facilities.

   type State is private;

   procedure Save  (Gen : Generator; To_State   : out State);
   procedure Reset (Gen : Generator; From_State : State);

   Max_Image_Width : constant := 80;

   function Image (Of_State    : State)  return String;
   function Value (Coded_State : String) return State;

private

   type Int_32 is range -2 ** 31 .. 2 ** 31 - 1;

   type Floating is digits 14;

   type State is record
      X1, X2, P, Q : Int_32;
      FP, Scale, Offset : Floating;
   end record;

   type Pointer is access State;

   function Create return Pointer;

   type Generator is record
      Point : Pointer := Create;
   end record;

end Ada.Numerics.Discrete_Random;