------------------------------------------------------------------------------
--                              Ada Web Server                              --
--                                                                          --
--                     Copyright (C) 2002-2017, AdaCore                     --
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--  This library is free software;  you can redistribute it and/or modify   --
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--  As a special exception, if other files instantiate generics from this   --
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------------------------------------------------------------------------------

pragma Ada_2012;

package AWS.Resources.Streams is

   type Stream_Type is abstract tagged limited private;

   type Stream_Access is access all Stream_Type'Class;

   function End_Of_File (Resource : Stream_Type) return Boolean is abstract;

   procedure Read
     (Resource : in out Stream_Type;
      Buffer   : out Stream_Element_Array;
      Last     : out Stream_Element_Offset) is abstract;

   procedure Reset (Resource : in out Stream_Type) is abstract;

   procedure Set_Index
     (Resource : in out Stream_Type;
      To       : Stream_Element_Offset) is abstract;
   --  Set the position in the stream, next Read will start at the position
   --  whose index is To. If To is outside the content the index is set to
   --  Last + 1 to ensure that next End_Of_File will return True.

   procedure Close (Resource : in out Stream_Type) is abstract;

   function Size (Resource : Stream_Type) return Stream_Element_Offset;
   --  This default implementation returns Undefined_Length. If the derived
   --  stream implementation knows about the size (in bytes) of the stream
   --  this routine should be redefined.

   function Name (Resource : Stream_Type) return String;
   --  This default implementation returns the empty string. It is must be
   --  overwritten by file based stream to provide the proper filename
   --  associated with the stream.

   procedure Create
     (Resource : out File_Type;
      Stream   : Stream_Access) with Inline;
   --  Create a resource file from user defined stream

private

   type Stream_Type is abstract new Resources.File_Tagged with null record;

end AWS.Resources.Streams;