gcc/ada/widechar.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                             W I D E C H A R                              --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2008, 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- --
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  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,  51  Franklin  Street,  Fifth  Floor, --
  20 -- Boston, MA 02110-1301, 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
  34 --  Note: this package uses the generic subprograms in System.Wch_Cnv, which
  35 --  completely encapsulate the set of wide character encoding methods, so no
  36 --  modifications are required when adding new encoding methods.
  37
  38 with Opt; use Opt;
  39
  40 with System.WCh_Cnv; use System.WCh_Cnv;
  41 with System.WCh_Con; use System.WCh_Con;
  42
  43 package body Widechar is
  44
  45    ---------------------------
  46    -- Is_Start_Of_Wide_Char --
  47    ---------------------------
  48
  49    function Is_Start_Of_Wide_Char
  50      (S : Source_Buffer_Ptr;
  51       P : Source_Ptr) return Boolean
  52    is
  53    begin
  54       case Wide_Character_Encoding_Method is
  55
  56          --  For Hex mode, just test for an ESC character. The ESC character
  57          --  cannot appear in any other context in a legal Ada program.
  58
  59          when WCEM_Hex =>
  60             return S (P) = ASCII.ESC;
  61
  62          --  For brackets, just test ["x where x is a hex character. This is
  63          --  sufficient test, since this sequence cannot otherwise appear in a
  64          --  legal Ada program.
  65
  66          when WCEM_Brackets =>
  67             return P <= S'Last - 2
  68               and then S (P) = '['
  69               and then S (P + 1) = '"'
  70               and then (S (P + 2) in '0' .. '9'
  71                             or else
  72                            S (P + 2) in 'a' .. 'f'
  73                             or else
  74                         S (P + 2) in 'A' .. 'F');
  75
  76          --  All other encoding methods use the upper bit set in the first
  77          --  character to uniquely represent a wide character.
  78
  79          when WCEM_Upper     |
  80               WCEM_Shift_JIS |
  81               WCEM_EUC       |
  82               WCEM_UTF8      =>
  83             return S (P) >= Character'Val (16#80#);
  84       end case;
  85    end Is_Start_Of_Wide_Char;
  86
  87    -----------------
  88    -- Length_Wide --
  89    -----------------
  90
  91    function Length_Wide return Nat is
  92    begin
  93       return WC_Longest_Sequence;
  94    end Length_Wide;
  95
  96    ---------------
  97    -- Scan_Wide --
  98    ---------------
  99
 100    procedure Scan_Wide
 101      (S   : Source_Buffer_Ptr;
 102       P   : in out Source_Ptr;
 103       C   : out Char_Code;
 104       Err : out Boolean)
 105    is
 106       P_Init : constant Source_Ptr := P;
 107       Chr    : Character;
 108
 109       function In_Char return Character;
 110       --  Function to obtain characters of wide character escape sequence
 111
 112       -------------
 113       -- In_Char --
 114       -------------
 115
 116       function In_Char return Character is
 117       begin
 118          P := P + 1;
 119          return S (P - 1);
 120       end In_Char;
 121
 122       function WC_In is new Char_Sequence_To_UTF_32 (In_Char);
 123
 124    --  Start of processing for Scan_Wide
 125
 126    begin
 127       Chr := In_Char;
 128
 129       --  Scan out the wide character. If the first character is a bracket,
 130       --  we allow brackets encoding regardless of the standard encoding
 131       --  method being used, but otherwise we use this standard method.
 132
 133       if Chr = '[' then
 134          C := Char_Code (WC_In (Chr, WCEM_Brackets));
 135       else
 136          C := Char_Code (WC_In (Chr, Wide_Character_Encoding_Method));
 137       end if;
 138
 139       Err := False;
 140       Wide_Char_Byte_Count := Wide_Char_Byte_Count + Nat (P - P_Init - 1);
 141
 142    exception
 143       when Constraint_Error =>
 144          C := Char_Code (0);
 145          P := P - 1;
 146          Err := True;
 147    end Scan_Wide;
 148
 149    --------------
 150    -- Set_Wide --
 151    --------------
 152
 153    procedure Set_Wide
 154      (C : Char_Code;
 155       S : in out String;
 156       P : in out Natural)
 157    is
 158       procedure Out_Char (C : Character);
 159       --  Procedure to store one character of wide character sequence
 160
 161       --------------
 162       -- Out_Char --
 163       --------------
 164
 165       procedure Out_Char (C : Character) is
 166       begin
 167          P := P + 1;
 168          S (P) := C;
 169       end Out_Char;
 170
 171       procedure WC_Out is new UTF_32_To_Char_Sequence (Out_Char);
 172
 173    --  Start of processing for Set_Wide
 174
 175    begin
 176       WC_Out (UTF_32_Code (C), Wide_Character_Encoding_Method);
 177    end Set_Wide;
 178
 179    ---------------
 180    -- Skip_Wide --
 181    ---------------
 182
 183    procedure Skip_Wide (S : String; P : in out Natural) is
 184       P_Init : constant Natural := P;
 185
 186       function Skip_Char return Character;
 187       --  Function to skip one character of wide character escape sequence
 188
 189       ---------------
 190       -- Skip_Char --
 191       ---------------
 192
 193       function Skip_Char return Character is
 194       begin
 195          P := P + 1;
 196          return S (P - 1);
 197       end Skip_Char;
 198
 199       function WC_Skip is new Char_Sequence_To_UTF_32 (Skip_Char);
 200
 201       Discard : UTF_32_Code;
 202       pragma Warnings (Off, Discard);
 203
 204    --  Start of processing for Skip_Wide
 205
 206    begin
 207       Discard := WC_Skip (Skip_Char, Wide_Character_Encoding_Method);
 208       Wide_Char_Byte_Count := Wide_Char_Byte_Count + Nat (P - P_Init - 1);
 209    end Skip_Wide;
 210
 211    ---------------
 212    -- Skip_Wide --
 213    ---------------
 214
 215    procedure Skip_Wide (S : Source_Buffer_Ptr; P : in out Source_Ptr) is
 216       P_Init : constant Source_Ptr := P;
 217
 218       function Skip_Char return Character;
 219       --  Function to skip one character of wide character escape sequence
 220
 221       ---------------
 222       -- Skip_Char --
 223       ---------------
 224
 225       function Skip_Char return Character is
 226       begin
 227          P := P + 1;
 228          return S (P - 1);
 229       end Skip_Char;
 230
 231       function WC_Skip is new Char_Sequence_To_UTF_32 (Skip_Char);
 232
 233       Discard : UTF_32_Code;
 234       pragma Warnings (Off, Discard);
 235
 236    --  Start of processing for Skip_Wide
 237
 238    begin
 239       Discard := WC_Skip (Skip_Char, Wide_Character_Encoding_Method);
 240       Wide_Char_Byte_Count := Wide_Char_Byte_Count + Nat (P - P_Init - 1);
 241    end Skip_Wide;
 242
 243 end Widechar;