1------------------------------------------------------------------------------ 2-- -- 3-- GNAT RUNTIME COMPONENTS -- 4-- -- 5-- S Y S T E M . W C H _ J I S -- 6-- -- 7-- B o d y -- 8-- -- 9-- Copyright (C) 1992,1993,1994 Free Software Foundation, Inc. -- 10-- -- 11-- GNAT is free software; you can redistribute it and/or modify it under -- 12-- terms of the GNU General Public License as published by the Free Soft- -- 13-- ware Foundation; either version 2, or (at your option) any later ver- -- 14-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- 15-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- 16-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- 17-- for more details. You should have received a copy of the GNU General -- 18-- Public License distributed with GNAT; see file COPYING. If not, write -- 19-- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, -- 20-- MA 02111-1307, USA. -- 21-- -- 22-- As a special exception, if other files instantiate generics from this -- 23-- unit, or you link this unit with other files to produce an executable, -- 24-- this unit does not by itself cause the resulting executable to be -- 25-- covered by the GNU General Public License. This exception does not -- 26-- however invalidate any other reasons why the executable file might be -- 27-- covered by the GNU Public License. -- 28-- -- 29-- GNAT was originally developed by the GNAT team at New York University. -- 30-- Extensive contributions were provided by Ada Core Technologies Inc. -- 31-- -- 32------------------------------------------------------------------------------ 33 34package body System.WCh_JIS is 35 36 type Byte is mod 256; 37 38 EUC_Hankaku_Kana : constant Byte := 16#8E#; 39 -- Prefix byte in EUC for Hankaku Kana (small Katakana). Such characters 40 -- in EUC are represented by a prefix byte followed by the code, which 41 -- is in the upper half (the corresponding JIS internal code is in the 42 -- range 16#0080# - 16#00FF#). 43 44 function EUC_To_JIS (EUC1, EUC2 : Character) return Wide_Character is 45 EUC1B : constant Byte := Character'Pos (EUC1); 46 EUC2B : constant Byte := Character'Pos (EUC2); 47 48 begin 49 if EUC2B not in 16#A0# .. 16#FE# then 50 raise Constraint_Error; 51 end if; 52 53 if EUC1B = EUC_Hankaku_Kana then 54 return Wide_Character'Val (EUC2B); 55 56 else 57 if EUC1B not in 16#A0# .. 16#FE# then 58 raise Constraint_Error; 59 else 60 return Wide_Character'Val 61 (256 * Natural (EUC1B and 16#7F#) + Natural (EUC2B and 16#7F#)); 62 end if; 63 end if; 64 end EUC_To_JIS; 65 66 ---------------- 67 -- JIS_To_EUC -- 68 ---------------- 69 70 procedure JIS_To_EUC 71 (J : in Wide_Character; 72 EUC1 : out Character; 73 EUC2 : out Character) 74 is 75 JIS1 : constant Natural := Wide_Character'Pos (J) / 256; 76 JIS2 : constant Natural := Wide_Character'Pos (J) rem 256; 77 78 begin 79 if JIS1 = 0 then 80 EUC1 := Character'Val (EUC_Hankaku_Kana); 81 EUC2 := Character'Val (JIS2); 82 83 else 84 EUC1 := Character'Val (JIS1 + 16#80#); 85 EUC2 := Character'Val (JIS2 + 16#80#); 86 end if; 87 end JIS_To_EUC; 88 89 ---------------------- 90 -- JIS_To_Shift_JIS -- 91 ---------------------- 92 93 procedure JIS_To_Shift_JIS 94 (J : in Wide_Character; 95 SJ1 : out Character; 96 SJ2 : out Character) 97 is 98 JIS1 : Byte; 99 JIS2 : Byte; 100 101 begin 102 -- The following is the required algorithm, it's hard to make any 103 -- more intelligent comments! This was copied from a public domain 104 -- C program called etos.c (author unknown). 105 106 JIS1 := Byte (Natural (Wide_Character'Pos (J) / 256)); 107 JIS2 := Byte (Natural (Wide_Character'Pos (J) rem 256)); 108 109 if JIS1 > 16#5F# then 110 JIS1 := JIS1 + 16#80#; 111 end if; 112 113 if (JIS1 mod 2) = 0 then 114 SJ1 := Character'Val ((JIS1 - 16#30#) / 2 + 16#88#); 115 SJ2 := Character'Val (JIS2 + 16#7E#); 116 117 else 118 if JIS2 >= 16#60# then 119 JIS2 := JIS2 + 16#01#; 120 end if; 121 122 SJ1 := Character'Val ((JIS1 - 16#31#) / 2 + 16#89#); 123 SJ2 := Character'Val (JIS2 + 16#1F#); 124 end if; 125 end JIS_To_Shift_JIS; 126 127 ---------------------- 128 -- Shift_JIS_To_JIS -- 129 ---------------------- 130 131 function Shift_JIS_To_JIS (SJ1, SJ2 : Character) return Wide_Character is 132 SJIS1 : Byte; 133 SJIS2 : Byte; 134 JIS1 : Byte; 135 JIS2 : Byte; 136 137 begin 138 -- The following is the required algorithm, it's hard to make any 139 -- more intelligent comments! This was copied from a public domain 140 -- C program called stoj.c written by shige@csk.JUNET. 141 142 SJIS1 := Character'Pos (SJ1); 143 SJIS2 := Character'Pos (SJ2); 144 145 if SJIS1 >= 16#E0# then 146 SJIS1 := SJIS1 - 16#40#; 147 end if; 148 149 if SJIS2 >= 16#9F# then 150 JIS1 := (SJIS1 - 16#88#) * 2 + 16#30#; 151 JIS2 := SJIS2 - 16#7E#; 152 153 else 154 if SJIS2 >= 16#7F# then 155 SJIS2 := SJIS2 - 16#01#; 156 end if; 157 158 JIS1 := (SJIS1 - 16#89#) * 2 + 16#31#; 159 JIS2 := SJIS2 - 16#1F#; 160 end if; 161 162 if JIS1 not in 16#20# .. 16#7E# 163 or else JIS2 not in 16#20# .. 16#7E# 164 then 165 raise Constraint_Error; 166 else 167 return Wide_Character'Val (256 * Natural (JIS1) + Natural (JIS2)); 168 end if; 169 end Shift_JIS_To_JIS; 170 171end System.WCh_JIS; 172