-----------------------------------------------------------------------------
--
--                     Onions Network Streams Library
--
--                      O N I O N S . P O I N T E R S
--
--                                 S p e c
--
--     Copyright (C) 1997-1998  Regents of the University of California
--
--  Onions is free software; you can redistribute it and/or modify it under
--  the terms of the GNU General Public License as published by the Free
--  Software Foundation, with or without the single exception listed below;
--  either version 2, or (at your option) any later version.  Onions is
--  distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
--  without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
--  PARTICULAR PURPOSE.  See the GNU General Public License for more details.
--  You should have received a copy of the GNU General Public License
--  distributed with Onions; see the file COPYING.  If not, write to the
--  Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA
--  02111-1307, USA.
--
--  As a special exception, if other files instantiate generics from this
--  library, or you link this library with other files to produce an
--  executable, this library does not by itself cause the resulting
--  executable to be covered by the GNU General Public License.  This
--  exception does not however invalidate any other reasons why the
--  executable file might be covered by the GNU General Public License.
--
--  Portions of this unit have been derived from version 1.02 of the Garlic
--  library of GLADE, the Ada95 Distributed Systems Annex for GNAT.  GLADE
--  is maintained by ACT Europe (see <http://www.act-europe.fr/glade.html>).
--
--     GLADE is Copyright (C) 1996,1997 Free Software Foundation, Inc.
--     All source code that is shared by both GLADE version 1.02 and
--     this unit remains under the FSF copyright.
--
-----------------------------------------------------------------------------

with Interfaces.C;

generic
   type Index is (<>);
   type Element is private;
   type Element_Array is array (Index range <>) of aliased Element;
   Default_Terminator : Element;

package Onions.Pointers is

   subtype ptrdiff_t is Interfaces.C.ptrdiff_t;

   type Pointer is access all Element;

   function Value
     (Ref        : in Pointer;
      Terminator : in Element := Default_Terminator)
      return       Element_Array;

   function Value
     (Ref    : in Pointer;
      Length : in ptrdiff_t)
      return   Element_Array;

   Pointer_Error : exception;

   --------------------------------
   -- C-style Pointer Arithmetic --
   --------------------------------

   function "+" (Left : in Pointer;   Right : in ptrdiff_t) return Pointer;
   function "+" (Left : in ptrdiff_t; Right : in Pointer)   return Pointer;
   function "-" (Left : in Pointer;   Right : in ptrdiff_t) return Pointer;
   function "-" (Left : in Pointer;   Right : in Pointer)   return ptrdiff_t;

   procedure Increment (Ref : in out Pointer);
   procedure Decrement (Ref : in out Pointer);

   pragma Convention (Intrinsic, "+");
   pragma Convention (Intrinsic, "-");
   pragma Convention (Intrinsic, Increment);
   pragma Convention (Intrinsic, Decrement);

   function Virtual_Length
     (Ref        : in Pointer;
      Terminator : in Element := Default_Terminator)
      return       ptrdiff_t;

   procedure Copy_Terminated_Array
     (Source     : in Pointer;
      Target     : in Pointer;
      Limit      : in ptrdiff_t := ptrdiff_t'Last;
      Terminator : in Element := Default_Terminator);

   procedure Copy_Array
     (Source  : in Pointer;
      Target  : in Pointer;
      Length  : in ptrdiff_t);

private
   pragma Inline ("+");
   pragma Inline ("-");
   pragma Inline (Decrement);
   pragma Inline (Increment);

end Onions.Pointers;