------------------------------------------------------------------------------
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--                          GNAT RUN-TIME COMPONENTS                        --
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--            A D A . S T R I N G S . U N B O U N D E D . A U X             --
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--          Copyright (C) 1992-2019, Free Software Foundation, Inc.         --
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-- GNAT is free software;  you can  redistribute it  and/or modify it under --
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------------------------------------------------------------------------------

--  This child package of Ada.Strings.Unbounded provides some specialized
--  access functions which are intended to allow more efficient use of the
--  facilities of Ada.Strings.Unbounded, particularly by other layered
--  utilities (such as GNAT.SPITBOL.Patterns).

package Ada.Strings.Unbounded.Aux is
   pragma Preelaborate;

   subtype Big_String is String (1 .. Positive'Last);
   pragma Suppress_Initialization (Big_String);
   --  Type used to obtain string access to given address. Initialization is
   --  suppressed, since we never want to have variables of this type, and
   --  we never want to attempt initialiazation of virtual variables of this
   --  type (e.g. when pragma Normalize_Scalars is used).

   type Big_String_Access is access all Big_String;
   for Big_String_Access'Storage_Size use 0;
   --  We use this access type to pass a pointer to an area of storage to be
   --  accessed as a string. Of course when this pointer is used, it is the
   --  responsibility of the accessor to ensure proper bounds. The storage
   --  size clause ensures we do not allocate variables of this type.

   procedure Get_String
     (U : Unbounded_String;
      S : out Big_String_Access;
      L : out Natural);
   pragma Inline (Get_String);
   --  This procedure returns the internal string pointer used in the
   --  representation of an unbounded string as well as the actual current
   --  length (which may be less than S.all'Length because in general there
   --  can be extra space assigned). The characters of this string may be
   --  not be modified via the returned pointer,  and are valid only as
   --  long as the original unbounded string is not accessed or modified.
   --
   --  This procedure is much more efficient than the use of To_String
   --  since it avoids the need to copy the string. The lower bound of the
   --  referenced string returned by this call is always one, so the actual
   --  string data is always accessible as S (1 .. L).

   procedure Set_String (UP : in out Unbounded_String; S : String_Access);
   pragma Inline (Set_String);
   --  This version of Set_Unbounded_String takes a string access value, rather
   --  than a string. The lower bound of the string value is required to be
   --  one, and this requirement is not checked.

end Ada.Strings.Unbounded.Aux;