# File : terminal_interface-curses-forms-field_types-user.adb

    ------------------------------------------------------------------------------
    --                                                                          --
    --                           GNAT ncurses Binding                           --
    --                                                                          --
    --              Terminal_Interface.Curses.Forms.Field_Types.User            --
    --                                                                          --
    --                                 B O D Y                                  --
    --                                                                          --
    ------------------------------------------------------------------------------
    -- Copyright (c) 1998 Free Software Foundation, Inc.                        --
    --                                                                          --
    -- Permission is hereby granted, free of charge, to any person obtaining a  --
    -- copy of this software and associated documentation files (the            --
    -- "Software"), to deal in the Software without restriction, including      --
    -- without limitation the rights to use, copy, modify, merge, publish,      --
    -- distribute, distribute with modifications, sublicense, and/or sell       --
    -- copies of the Software, and to permit persons to whom the Software is    --
    -- furnished to do so, subject to the following conditions:                 --
    --                                                                          --
    -- The above copyright notice and this permission notice shall be included  --
    -- in all copies or substantial portions of the Software.                   --
    --                                                                          --
    -- THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  --
    -- OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               --
    -- MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   --
    -- IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,   --
    -- DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR    --
    -- OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR    --
    -- THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               --
    --                                                                          --
    -- Except as contained in this notice, the name(s) of the above copyright   --
    -- holders shall not be used in advertising or otherwise to promote the     --
    -- sale, use or other dealings in this Software without prior written       --
    -- authorization.                                                           --
    ------------------------------------------------------------------------------
    --  Author: Jürgen Pfeifer <<juergen.pfeifer@gmx.net>> 1996
    --  Version Control:
    --  @Revision: 1.8 @
    --  Binding Version 01.00
    ------------------------------------------------------------------------------
    with Ada.Unchecked_Conversion;
    with Interfaces.C;
    with Terminal_Interface.Curses.Aux; use Terminal_Interface.Curses.Aux;

    package body Terminal_Interface.Curses.Forms.Field_Types.User is

       use type Interfaces.C.int;

       procedure Set_Field_Type (Fld : in Field;
                                 Typ : in User_Defined_Field_Type)
       is
          function Allocate_Arg (T : User_Defined_Field_Type'Class)
                                 return Argument_Access;

          function Set_Fld_Type (F    : Field := Fld;
                                 Cft  : C_Field_Type := C_Generic_Type;
                                 Arg1 : Argument_Access)
                                 return C_Int;
          pragma Import (C, Set_Fld_Type, "set_field_type");

          Res : Eti_Error;

          function Allocate_Arg (T : User_Defined_Field_Type'Class)
                                 return Argument_Access
          is
             Ptr : Field_Type_Access := new User_Defined_Field_Type'Class'(T);
          begin
             return new Argument'(Usr => System.Null_Address,
                                  Typ => Ptr,
                                  Cft => Null_Field_Type);
          end Allocate_Arg;

       begin
          Res := Set_Fld_Type (Arg1 => Allocate_Arg (Typ));
          if Res /= E_Ok then
             Eti_Exception (Res);
          end if;
       end Set_Field_Type;

       function To_Argument_Access is new Ada.Unchecked_Conversion
         (System.Address, Argument_Access);

       function Generic_Field_Check (Fld : Field;
                                     Usr : System.Address) return C_Int
       is
          Result : Boolean;
          Udf    : User_Defined_Field_Type_Access :=
            User_Defined_Field_Type_Access (To_Argument_Access (Usr).Typ);
       begin
          Result := Field_Check (Fld, Udf.all);
          return C_Int (Boolean'Pos (Result));
       end Generic_Field_Check;

       function Generic_Char_Check (Ch  : C_Int;
                                    Usr : System.Address) return C_Int
       is
          Result : Boolean;
          Udf    : User_Defined_Field_Type_Access :=
            User_Defined_Field_Type_Access (To_Argument_Access (Usr).Typ);
       begin
          Result := Character_Check (Character'Val (Ch), Udf.all);
          return C_Int (Boolean'Pos (Result));
       end Generic_Char_Check;

       --  -----------------------------------------------------------------------
       --
       function C_Generic_Type return C_Field_Type
       is
          Res : Eti_Error;
          T   : C_Field_Type;
       begin
          if M_Generic_Type = Null_Field_Type then
             T := New_Fieldtype (Generic_Field_Check'Access,
                                 Generic_Char_Check'Access);
             if T = Null_Field_Type then
                raise Form_Exception;
             else
                Res := Set_Fieldtype_Arg (T,
                                          Make_Arg'Access,
                                          Copy_Arg'Access,
                                          Free_Arg'Access);
                if Res /= E_Ok then
                   Eti_Exception (Res);
                end if;
             end if;
             M_Generic_Type := T;
          end if;
          pragma Assert (M_Generic_Type /= Null_Field_Type);
          return M_Generic_Type;
       end C_Generic_Type;

    end Terminal_Interface.Curses.Forms.Field_Types.User;