------------------------------------------------------------------------------
--                                                                          --
--                         GNAT RUN-TIME COMPONENTS                         --
--                                                                          --
--                       S Y S T E M . W C H _ J I S                        --
--                                                                          --
--                                 S p e c                                  --
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--          Copyright (C) 1992-2022, 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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-- GNAT was originally developed  by the GNAT team at  New York University. --
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--                                                                          --
------------------------------------------------------------------------------

--  This package contains routines used for converting between internal
--  JIS codes and the two external forms we support (EUC and Shift-JIS)

package System.WCh_JIS is
   pragma Pure;

   function EUC_To_JIS (EUC1, EUC2 : Character) return Wide_Character;
   --  Given the two bytes of a EUC representation, return the
   --  corresponding JIS code wide character. Raises Constraint_Error
   --  if the two characters are not a valid EUC encoding.

   procedure JIS_To_EUC
     (J    : Wide_Character;
      EUC1 : out Character;
      EUC2 : out Character);

   --  Given a wide character in JIS form, produce the corresponding
   --  two bytes of the EUC representation of this character. This is
   --  only used if J is not in the normal ASCII range, i.e. on entry
   --  we know that Wide_Character'Pos (J) >= 16#0080# and that we
   --  thus require a two byte EUC representation (ASCII codes appear
   --  unchanged as a single byte in EUC). No error checking is performed,
   --  the input code is assumed to be in an appropriate range.

   procedure JIS_To_Shift_JIS
     (J   : Wide_Character;
      SJ1 : out Character;
      SJ2 : out Character);
   --  Given a wide character code in JIS form, produce the corresponding
   --  two bytes of the Shift-JIS representation of this character. This
   --  is only used if J is not in the normal ASCII range, i.e. on entry
   --  we know that Wide_Character'Pos (J) >= 16#0080# and that we
   --  thus require a two byte EUC representation (ASCII codes appear
   --  unchanged as a single byte in EUC). No error checking is performed,
   --  the input code is assumed to be in an appropriate range (note in
   --  particular that input codes in the range 16#0080#-16#00FF#, i.e.
   --  Hankaku Kana, do not appear, since Shift JIS has no representation
   --  for such codes.

   function Shift_JIS_To_JIS (SJ1, SJ2 : Character) return Wide_Character;
   --  Given the two bytes of a Shift-JIS representation, return the
   --  corresponding JIS code wide character. Raises Constraint_Error if
   --  the two characters are not a valid shift-JIS encoding.

end System.WCh_JIS;
