------------------------------------------------------------------------------ -- -- -- GNAT RUNTIME COMPONENTS -- -- -- -- S Y S T E M . W C H _ J I S -- -- -- -- B o d y -- -- -- -- Copyright (C) 1992,1993,1994 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. -- -- Extensive contributions were provided by Ada Core Technologies Inc. -- -- -- ------------------------------------------------------------------------------ package body System.WCh_JIS is type Byte is mod 256; EUC_Hankaku_Kana : constant Byte := 16#8E#; -- Prefix byte in EUC for Hankaku Kana (small Katakana). Such characters -- in EUC are represented by a prefix byte followed by the code, which -- is in the upper half (the corresponding JIS internal code is in the -- range 16#0080# - 16#00FF#). function EUC_To_JIS (EUC1, EUC2 : Character) return Wide_Character is EUC1B : constant Byte := Character'Pos (EUC1); EUC2B : constant Byte := Character'Pos (EUC2); begin if EUC2B not in 16#A0# .. 16#FE# then raise Constraint_Error; end if; if EUC1B = EUC_Hankaku_Kana then return Wide_Character'Val (EUC2B); else if EUC1B not in 16#A0# .. 16#FE# then raise Constraint_Error; else return Wide_Character'Val (256 * Natural (EUC1B and 16#7F#) + Natural (EUC2B and 16#7F#)); end if; end if; end EUC_To_JIS; ---------------- -- JIS_To_EUC -- ---------------- procedure JIS_To_EUC (J : in Wide_Character; EUC1 : out Character; EUC2 : out Character) is JIS1 : constant Natural := Wide_Character'Pos (J) / 256; JIS2 : constant Natural := Wide_Character'Pos (J) rem 256; begin if JIS1 = 0 then EUC1 := Character'Val (EUC_Hankaku_Kana); EUC2 := Character'Val (JIS2); else EUC1 := Character'Val (JIS1 + 16#80#); EUC2 := Character'Val (JIS2 + 16#80#); end if; end JIS_To_EUC; ---------------------- -- JIS_To_Shift_JIS -- ---------------------- procedure JIS_To_Shift_JIS (J : in Wide_Character; SJ1 : out Character; SJ2 : out Character) is JIS1 : Byte; JIS2 : Byte; begin -- The following is the required algorithm, it's hard to make any -- more intelligent comments! This was copied from a public domain -- C program called etos.c (author unknown). JIS1 := Byte (Natural (Wide_Character'Pos (J) / 256)); JIS2 := Byte (Natural (Wide_Character'Pos (J) rem 256)); if JIS1 > 16#5F# then JIS1 := JIS1 + 16#80#; end if; if (JIS1 mod 2) = 0 then SJ1 := Character'Val ((JIS1 - 16#30#) / 2 + 16#88#); SJ2 := Character'Val (JIS2 + 16#7E#); else if JIS2 >= 16#60# then JIS2 := JIS2 + 16#01#; end if; SJ1 := Character'Val ((JIS1 - 16#31#) / 2 + 16#89#); SJ2 := Character'Val (JIS2 + 16#1F#); end if; end JIS_To_Shift_JIS; ---------------------- -- Shift_JIS_To_JIS -- ---------------------- function Shift_JIS_To_JIS (SJ1, SJ2 : Character) return Wide_Character is SJIS1 : Byte; SJIS2 : Byte; JIS1 : Byte; JIS2 : Byte; begin -- The following is the required algorithm, it's hard to make any -- more intelligent comments! This was copied from a public domain -- C program called stoj.c written by shige@csk.JUNET. SJIS1 := Character'Pos (SJ1); SJIS2 := Character'Pos (SJ2); if SJIS1 >= 16#E0# then SJIS1 := SJIS1 - 16#40#; end if; if SJIS2 >= 16#9F# then JIS1 := (SJIS1 - 16#88#) * 2 + 16#30#; JIS2 := SJIS2 - 16#7E#; else if SJIS2 >= 16#7F# then SJIS2 := SJIS2 - 16#01#; end if; JIS1 := (SJIS1 - 16#89#) * 2 + 16#31#; JIS2 := SJIS2 - 16#1F#; end if; if JIS1 not in 16#20# .. 16#7E# or else JIS2 not in 16#20# .. 16#7E# then raise Constraint_Error; else return Wide_Character'Val (256 * Natural (JIS1) + Natural (JIS2)); end if; end Shift_JIS_To_JIS; end System.WCh_JIS;