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1996-01-30
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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- S Y S T E M . W C H _ C O N --
-- --
-- S p e c --
-- --
-- $Revision: 1.3 $ --
-- --
-- Copyright (c) 1992,1993,1994 NYU, All Rights Reserved --
-- --
-- The GNAT library is free software; you can redistribute it and/or modify --
-- it under terms of the GNU Library General Public License as published by --
-- the Free Software Foundation; either version 2, or (at your option) any --
-- later version. The GNAT library 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 --
-- Library General Public License for more details. You should have --
-- received a copy of the GNU Library General Public License along with --
-- the GNAT library; see the file COPYING.LIB. If not, write to the Free --
-- Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. --
-- --
------------------------------------------------------------------------------
-- This package defines the codes used to identify the encoding method for
-- wide characters in string and character constants. This is needed both
-- at compile time and at runtime (for the wide character runtime routines)
package System.WCh_Con is
pragma Pure (WCh_Con);
type WC_Encoding_Method is range 0 .. 3;
-- Type covering the range of values used to represent wide character
-- encoding methods. An enumeration type might be a little neater, but
-- more trouble than it's worth, given the need to pass these values
-- from the compiler to the backend, and to record them in the ALI file.
WCEM_Hex : constant WC_Encoding_Method := 0;
-- The wide character with code 16#abcd# is represented by the
-- escape sequence ESC a b c d (five characters, where abcd are
-- ASCII hex characters, using upper case for letters). This
-- method is easy to deal with in external environments that do
-- not support wide characters, and covers the whole BMP. This
-- is the default encoding method.
WCEM_Upper : constant WC_Encoding_Method := 1;
-- The wide character with encoding 16#abcd#, where the upper bit
-- is on (i.e. a is in the range 8-F) is represented as two bytes
-- 16#ab# and 16#cd#. The second byte may never be a format control
-- character, but is not required to be in the upper half. This
-- method can be also used for shift-JIS or EUC where the internal
-- coding matches the external coding.
WCEM_Shift_JIS : constant WC_Encoding_Method := 2;
-- A wide character is represented by a two character sequence
-- 16#ab# and 16#cd#, with the restrictions described for upper
-- half encoding as described above. The internal character code
-- is the corresponding JIS character according to the standard
-- algorithm for Shift-JIS conversion. See the body of package
-- System.JIS_Conversions for further details.
WCEM_EUC : constant WC_Encoding_Method := 3;
-- A wide character is represented by a two character sequence
-- 16#ab# and 16#cd#, with both characters being in the upper half.
-- The internal character code is the corresponding JIS character
-- according to the EUC encoding algorithm. See the body of package
-- System.JIS_Conversions for further details.
end System.WCh_Con;