-----------------------------------------------------------------------------
--
--         libwww-ada95 : A World Wide Web client library for Ada95
--
--                       W W W . F I E L D _ N A M E S
--
--                                 B o d y
--
--     Copyright (C) 1997-1998  Regents of the University of California
--
--  libwww-ada95 is free software; you can redistribute it and/or modify it
--  under the terms of the GNU General Public License as published by the Free
--  Software Foundation, with or without the single exception listed below;
--  either version 2, or (at your option) any later version.  libwww-ada95 is
--  distributed in the hope that it will be useful, but WITHOUT 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 libwww-ada95; see the 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
--  library, or you link this library with other files to produce an
--  executable, this library 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 General Public License.
--
--  Created in 1997 by Kari Nies
-----------------------------------------------------------------------------


package body WWW.Field_Names is


   --  for Nazi style checker
   function Lower_Case (UBS : UB_String) return STRING;
   function Replace_Hypens (UBS : UB_String) return String;
   function Check_Special_Cases (Field_Name : UB_String) return Field_Name;


   --  convert a unbounded string to a lower case constrained string
   function Lower_Case (UBS : UB_String) return STRING is
      S : STRING (1 .. UB_Strings.Length (UBS)) := UB_Strings.To_String (UBS);
      C : CHARACTER;
   begin
      for i in 1 .. S'Length loop
         C := S (i);
         if C in 'A' .. 'Z' then
            S (i) := Character'Val (Character'Pos (C) +
                                    Character'Pos ('a') -
                                    Character'Pos ('A'));
         end if;
      end loop;
      return S;
   end Lower_Case;


   --  convert a unbounded string to a constrained string with all hyphens
   --  converted to underscores
   function Replace_Hypens (UBS : UB_String) return String is
      S : STRING (1 .. UB_Strings.Length (UBS)) := UB_Strings.To_String (UBS);
      C : CHARACTER;
   begin
      for i in 1 .. S'Length loop
         C := S (i);
         if C = '-' then
            S (i) := '_';
         end if;
      end loop;
      return S;
   end Replace_Hypens;
   

   use UB_Strings;
   function Check_Special_Cases (Field_Name : UB_String)
      return Field_Name is
      Lower_Field_Name : UB_String :=
          UB_Strings.To_Unbounded_String (Lower_Case (Field_Name));
   begin
      if Lower_Field_Name = "pragma" then
         return XPragma;
      elsif Lower_Field_Name = "accept" then
         return XAccept;
      elsif Lower_Field_Name = "range" then
         return XRange;
      else
         return Unknown;
      end if;
   end Check_Special_Cases;


   function Parse_Field_Name (FN_Str : UB_String) return Field_Name is
   begin
      --  try straign coversion
      return Field_Name'Value (Replace_Hypens (FN_Str));
   exception
      when CONSTRAINT_ERROR =>
         --  guaranteed to return special case or unknown
         return Check_Special_Cases (FN_Str);
   end Parse_Field_Name;
 

   function Field_Name_2_Id (FN : Field_Name) return NATURAL is
   begin
      return Field_Name'Pos (FN);
   end Field_Name_2_Id;


end WWW.Field_Names;