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------------------------------------------------------------------------------

--                                                                          --

--                         GNAT COMPILER COMPONENTS                         --

--                                                                          --

--                             W I D E C H A R                              --

--                                                                          --

--                                 B o d y                                  --

--                                                                          --

--          Copyright (C) 1992-2009 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 3,  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.                                     --

--                                                                          --

-- As a special exception under Section 7 of GPL version 3, you are granted --

-- additional permissions described in the GCC Runtime Library Exception,   --

-- version 3.1, as published by the Free Software Foundation.               --

--                                                                          --

-- You should have received a copy of the GNU General Public License and    --

-- a copy of the GCC Runtime Library Exception along with this program;     --

-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --

-- <http://www.gnu.org/licenses/>.                                          --

--                                                                          --

-- GNAT was originally developed  by the GNAT team at  New York University. --

-- Extensive contributions were provided by Ada Core Technologies Inc.      --

--                                                                          --

------------------------------------------------------------------------------

--  Note: this package uses the generic subprograms in System.Wch_Cnv, which

--  completely encapsulate the set of wide character encoding methods, so no

--  modifications are required when adding new encoding methods.

with Opt; use Opt;

with System.WCh_Cnv; use System.WCh_Cnv;

with System.WCh_Con; use System.WCh_Con;

package body Widechar is

   ---------------------------

   -- Is_Start_Of_Wide_Char --

   ---------------------------

   function Is_Start_Of_Wide_Char

     (S : Source_Buffer_Ptr;

      P : Source_Ptr) return Boolean

   is

   begin

      case Wide_Character_Encoding_Method is

         --  For Hex mode, just test for an ESC character. The ESC character

         --  cannot appear in any other context in a legal Ada program.

         when WCEM_Hex =>

            return S (P) = ASCII.ESC;

         --  For brackets, just test ["x where x is a hex character. This is

         --  sufficient test, since this sequence cannot otherwise appear in a

         --  legal Ada program.

         when WCEM_Brackets =>

            return P <= S'Last - 2

              and then S (P) = '['

              and then S (P + 1) = '"'

              and then (S (P + 2) in '0' .. '9'

                            or else

                           S (P + 2) in 'a' .. 'f'

                            or else

                        S (P + 2) in 'A' .. 'F');

         --  All other encoding methods use the upper bit set in the first

         --  character to uniquely represent a wide character.

         when WCEM_Upper     |

              WCEM_Shift_JIS |

              WCEM_EUC       |

              WCEM_UTF8      =>

            return S (P) >= Character'Val (16#80#);

      end case;

   end Is_Start_Of_Wide_Char;

   -----------------

   -- Length_Wide --

   -----------------

   function Length_Wide return Nat is

   begin

      return WC_Longest_Sequence;

   end Length_Wide;

   ---------------

   -- Scan_Wide --

   ---------------

   procedure Scan_Wide

     (S   : Source_Buffer_Ptr;

      P   : in out Source_Ptr;

      C   : out Char_Code;

      Err : out Boolean)

   is

      P_Init : constant Source_Ptr := P;

      Chr    : Character;

      function In_Char return Character;

      --  Function to obtain characters of wide character escape sequence

      -------------

      -- In_Char --

      -------------

      function In_Char return Character is

      begin

         P := P + 1;

         return S (P - 1);

      end In_Char;

      function WC_In is new Char_Sequence_To_UTF_32 (In_Char);

   --  Start of processing for Scan_Wide

   begin

      Chr := In_Char;

      --  Scan out the wide character. If the first character is a bracket,

      --  we allow brackets encoding regardless of the standard encoding

      --  method being used, but otherwise we use this standard method.

      if Chr = '[' then

         C := Char_Code (WC_In (Chr, WCEM_Brackets));

      else

         C := Char_Code (WC_In (Chr, Wide_Character_Encoding_Method));

      end if;

      Err := False;

      Wide_Char_Byte_Count := Wide_Char_Byte_Count + Nat (P - P_Init - 1);

   exception

      when Constraint_Error =>

         C := Char_Code (0);

         P := P - 1;

         Err := True;

   end Scan_Wide;

   --------------

   -- Set_Wide --

   --------------

   procedure Set_Wide

     (C : Char_Code;

      S : in out String;

      P : in out Natural)

   is

      procedure Out_Char (C : Character);

      --  Procedure to store one character of wide character sequence

      --------------

      -- Out_Char --

      --------------

      procedure Out_Char (C : Character) is

      begin

         P := P + 1;

         S (P) := C;

      end Out_Char;

      procedure WC_Out is new UTF_32_To_Char_Sequence (Out_Char);

   --  Start of processing for Set_Wide

   begin

      WC_Out (UTF_32_Code (C), Wide_Character_Encoding_Method);

   end Set_Wide;

   ---------------

   -- Skip_Wide --

   ---------------

   procedure Skip_Wide (S : String; P : in out Natural) is

      P_Init : constant Natural := P;

      function Skip_Char return Character;

      --  Function to skip one character of wide character escape sequence

      ---------------

      -- Skip_Char --

      ---------------

      function Skip_Char return Character is

      begin

         P := P + 1;

         return S (P - 1);

      end Skip_Char;

      function WC_Skip is new Char_Sequence_To_UTF_32 (Skip_Char);

      Discard : UTF_32_Code;

      pragma Warnings (Off, Discard);

   --  Start of processing for Skip_Wide

   begin

      Discard := WC_Skip (Skip_Char, Wide_Character_Encoding_Method);

      Wide_Char_Byte_Count := Wide_Char_Byte_Count + Nat (P - P_Init - 1);

   end Skip_Wide;

   ---------------

   -- Skip_Wide --

   ---------------

   procedure Skip_Wide (S : Source_Buffer_Ptr; P : in out Source_Ptr) is

      P_Init : constant Source_Ptr := P;

      function Skip_Char return Character;

      --  Function to skip one character of wide character escape sequence

      ---------------

      -- Skip_Char --

      ---------------

      function Skip_Char return Character is

      begin

         P := P + 1;

         return S (P - 1);

      end Skip_Char;

      function WC_Skip is new Char_Sequence_To_UTF_32 (Skip_Char);

      Discard : UTF_32_Code;

      pragma Warnings (Off, Discard);

   --  Start of processing for Skip_Wide

   begin

      Discard := WC_Skip (Skip_Char, Wide_Character_Encoding_Method);

      Wide_Char_Byte_Count := Wide_Char_Byte_Count + Nat (P - P_Init - 1);

   end Skip_Wide;

end Widechar;