------------------------------------------------------------------------------
--                                                                          --
--                         GNAT LIBRARY COMPONENTS                          --
--                                                                          --
--         A D A . S T R E A M S . S T O R A G E . U N B O U N D E D        --
--                                                                          --
--                                 S p e c                                  --
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--             Copyright (C) 2020, Free Software Foundation, Inc.           --
--                                                                          --
-- This specification is derived from the Ada Reference Manual for use with --
-- GNAT. The copyright notice above, and the license provisions that follow --
-- apply solely to the  contents of the part following the private keyword. --
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-- GNAT is free software;  you can  redistribute it  and/or modify it under --
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--                                                                          --
------------------------------------------------------------------------------

private with Ada.Finalization;

package Ada.Streams.Storage.Unbounded with Preelaborate is

   type Stream_Type is new Storage_Stream_Type with private with
      Default_Initial_Condition => Element_Count (Stream_Type) = 0;

   overriding procedure Read
     (Stream : in out Stream_Type; Item : out Stream_Element_Array;
      Last   :    out Stream_Element_Offset)
       with Post =>
         (declare
            Num_Read : constant Stream_Element_Count :=
              Stream_Element_Count'Min
                (Element_Count (Stream)'Old, Item'Length);
          begin
            Last = Num_Read + Item'First - 1
              and
            Element_Count (Stream) =
              Element_Count (Stream)'Old - Num_Read);

   overriding procedure Write
     (Stream : in out Stream_Type; Item : Stream_Element_Array) with
      Post => Element_Count (Stream) =
      Element_Count (Stream)'Old + Item'Length;

   overriding function Element_Count
     (Stream : Stream_Type) return Stream_Element_Count;

   overriding procedure Clear (Stream : in out Stream_Type) with
      Post => Element_Count (Stream) = 0;

private

   subtype Stream_Element_Index is Stream_Element_Count
     range 1 .. Stream_Element_Count'Last;

   type Elements_Type (Last : Stream_Element_Count) is limited record
      EA : Stream_Element_Array (1 .. Last);
   end record;

   Empty_Elements : aliased Elements_Type (0);

   type Elements_Access is access all Elements_Type;

   type Controlled_Elements_Access is
     new Finalization.Limited_Controlled with record
      A : Elements_Access;
   end record;

   overriding procedure Finalize (X : in out Controlled_Elements_Access);

   type Stream_Type is new Storage_Stream_Type with record
      Elements : Controlled_Elements_Access :=
        (Finalization.Limited_Controlled with A => Empty_Elements'Access);
      Count : Stream_Element_Count := 0;
   end record;

end Ada.Streams.Storage.Unbounded;