s-widenu.adb   [plain text]

------------------------------------------------------------------------------
--                                                                          --
--                         GNAT RUNTIME COMPONENTS                          --
--                                                                          --
--                      S Y S T E M . W I D _ E N U M                       --
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--                                 B o d y                                  --
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--          Copyright (C) 1992-2001 Free Software Foundation, Inc.          --
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-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
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-- As a special exception,  if other files  instantiate  generics from this --
-- unit, or you link  this unit with other files  to produce an executable, --
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-- covered by the  GNU Public License.                                      --
--                                                                          --
-- GNAT was originally developed  by the GNAT team at  New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc.      --
--                                                                          --
------------------------------------------------------------------------------

with Unchecked_Conversion;

package body System.Wid_Enum is

   -------------------------
   -- Width_Enumeration_8 --
   -------------------------

   function Width_Enumeration_8
     (Names   : String;
      Indexes : System.Address;
      Lo, Hi  : Natural)
      return    Natural
   is
      pragma Warnings (Off, Names);

      W : Natural;

      type Natural_8 is range 0 .. 2 ** 7 - 1;
      type Index_Table is array (Natural) of Natural_8;
      type Index_Table_Ptr is access Index_Table;

      function To_Index_Table_Ptr is
        new Unchecked_Conversion (System.Address, Index_Table_Ptr);

      IndexesT : constant Index_Table_Ptr := To_Index_Table_Ptr (Indexes);

   begin
      W := 0;

      for J in Lo .. Hi loop
         W := Natural'Max (W, Natural (IndexesT (J + 1) - IndexesT (J)));
      end loop;

      return W;
   end Width_Enumeration_8;

   --------------------------
   -- Width_Enumeration_16 --
   --------------------------

   function Width_Enumeration_16
     (Names   : String;
      Indexes : System.Address;
      Lo, Hi  : Natural)
      return    Natural
   is
      pragma Warnings (Off, Names);

      W : Natural;

      type Natural_16 is range 0 .. 2 ** 15 - 1;
      type Index_Table is array (Natural) of Natural_16;
      type Index_Table_Ptr is access Index_Table;

      function To_Index_Table_Ptr is
        new Unchecked_Conversion (System.Address, Index_Table_Ptr);

      IndexesT : constant Index_Table_Ptr := To_Index_Table_Ptr (Indexes);

   begin
      W := 0;

      for J in Lo .. Hi loop
         W := Natural'Max (W, Natural (IndexesT (J + 1) - IndexesT (J)));
      end loop;

      return W;
   end Width_Enumeration_16;

   --------------------------
   -- Width_Enumeration_32 --
   --------------------------

   function Width_Enumeration_32
     (Names   : String;
      Indexes : System.Address;
      Lo, Hi  : Natural)
      return    Natural
   is
      pragma Warnings (Off, Names);

      W : Natural;

      type Natural_32 is range 0 .. 2 ** 31 - 1;
      type Index_Table is array (Natural) of Natural_32;
      type Index_Table_Ptr is access Index_Table;

      function To_Index_Table_Ptr is
        new Unchecked_Conversion (System.Address, Index_Table_Ptr);

      IndexesT : constant Index_Table_Ptr := To_Index_Table_Ptr (Indexes);

   begin
      W := 0;

      for J in Lo .. Hi loop
         W := Natural'Max (W, Natural (IndexesT (J + 1) - IndexesT (J)));
      end loop;

      return W;
   end Width_Enumeration_32;

end System.Wid_Enum;