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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- S Y S T E M . V A L _ W C H A R --
-- --
-- B o d y --
-- --
-- --
-- Copyright (C) 1992-1997, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 2, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT 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 GNAT; see 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 --
-- unit, or you link this unit with other files to produce an executable, --
-- this unit 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 Public License. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
-- --
------------------------------------------------------------------------------
with System.Val_Util; use System.Val_Util;
with System.WCh_Con; use System.WCh_Con;
with System.WCh_StW; use System.WCh_StW;
package body System.Val_WChar is
--------------------------
-- Value_Wide_Character --
--------------------------
function Value_Wide_Character
(Str : String;
EM : WC_Encoding_Method)
return Wide_Character
is
F : Natural;
L : Natural;
S : String (Str'Range) := Str;
begin
Normalize_String (S, F, L);
-- Character literal case
if S (F) = ''' and then S (L) = ''' then
-- If just three characters, simple character case
if L - F = 2 then
return Wide_Character'Val (Character'Pos (S (F + 1)));
-- Otherwise must be a wide character in quotes. The easiest
-- thing is to convert the string to a wide string and then
-- pick up the single character that it should contain.
else
declare
WS : constant Wide_String :=
String_To_Wide_String (S (F + 1 .. L - 1), EM);
begin
if WS'Length /= 1 then
raise Constraint_Error;
else
return WS (WS'First);
end if;
end;
end if;
-- the last two values of the type have language-defined names:
elsif S = "FFFE" then
return Wide_Character'Val (16#FFFE#);
elsif S = "FFFF" then
return Wide_Character'Val (16#FFFF#);
-- Otherwise must be a control character
else
for C in Character'Val (16#00#) .. Character'Val (16#1F#) loop
if S (F .. L) = Character'Image (C) then
return Wide_Character'Val (Character'Pos (C));
end if;
end loop;
for C in Character'Val (16#7F#) .. Character'Val (16#9F#) loop
if S (F .. L) = Character'Image (C) then
return Wide_Character'Val (Character'Pos (C));
end if;
end loop;
raise Constraint_Error;
end if;
end Value_Wide_Character;
end System.Val_WChar;
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