------------------------------------------------------------------------------
--                                                                          --
--                         GNAT RUNTIME COMPONENTS                          --
--                                                                          --
--              A D A . S T R I N G S . W I D E _ S E A R C H               --
--                                                                          --
--                                 B o d y                                  --
--                                                                          --
--                            $Revision: 1.7 $                              --
--                                                                          --
--        Copyright (C) 1992,1993,1994 Free Software Foundation, Inc.       --
--                                                                          --
-- GNAT is free software;  you can  redistribute it  and/or modify it under --
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-- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
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-- As a special exception,  if other files  instantiate  generics from this --
-- unit, or you link  this unit with other files  to produce an executable, --
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-- covered by the  GNU Public License.                                      --
--                                                                          --
-- GNAT was originally developed  by the GNAT team at  New York University. --
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--                                                                          --
------------------------------------------------------------------------------

with Ada.Strings.Wide_Maps; use Ada.Strings.Wide_Maps;

package body Ada.Strings.Wide_Search is

   -----------------------
   -- Local Subprograms --
   -----------------------

   function Belongs
     (Element : Wide_Character;
      Set     : Wide_Maps.Wide_Character_Set;
      Test    : Membership)
      return    Boolean;
   pragma Inline (Belongs);
   --  Determines if the given element is in (Test = Inside) or not in
   --  (Test = Outside) the given character set.

   -------------
   -- Belongs --
   -------------

   function Belongs
     (Element : Wide_Character;
      Set     : Wide_Maps.Wide_Character_Set;
      Test    : Membership)
      return    Boolean is

   begin
      if Test = Inside then
         return Is_In (Element, Set);
      else
         return not Is_In (Element, Set);
      end if;
   end Belongs;

   -----------
   -- Count --
   -----------

   function Count
     (Source   : in Wide_String;
      Pattern  : in Wide_String;
      Mapping  : in Wide_Maps.Wide_Character_Mapping := Wide_Maps.Identity)
      return     Natural
   is
      N : Natural;
      J : Natural;

   begin
      if Pattern = "" then
         raise Pattern_Error;
      end if;

      --  Handle the case of non-identity mappings by creating a mapped
      --  string and making a recursive call using the identity mapping
      --  on this mapped string.

      if Mapping /= Wide_Maps.Identity then
         declare
            Mapped_Source : Wide_String (Source'Range);

         begin
            for J in Source'Range loop
               Mapped_Source (J) := Value (Mapping, Source (J));
            end loop;

            return Count (Mapped_Source, Pattern);
         end;
      end if;

      N := 0;
      J := Source'First;

      while J <= Source'Last - (Pattern'Length - 1) loop
         if Source (J .. J + (Pattern'Length - 1)) = Pattern then
            N := N + 1;
            J := J + Pattern'Length;
         else
            J := J + 1;
         end if;
      end loop;

      return N;
   end Count;

   function Count
     (Source   : in Wide_String;
      Pattern  : in Wide_String;
      Mapping  : in Wide_Maps.Wide_Character_Mapping_Function)
      return     Natural
   is
      Mapped_Source : Wide_String (Source'Range);

   begin
      for J in Source'Range loop
         Mapped_Source (J) := Mapping (Source (J));
      end loop;

      return Count (Mapped_Source, Pattern);
   end Count;

   function Count (Source : in Wide_String;
                   Set    : in Wide_Maps.Wide_Character_Set)
     return Natural
   is
      N : Natural := 0;

   begin
      for J in Source'Range loop
         if Is_In (Source (J), Set) then
            N := N + 1;
         end if;
      end loop;

      return N;
   end Count;

   ----------------
   -- Find_Token --
   ----------------

   procedure Find_Token
     (Source : in Wide_String;
      Set    : in Wide_Maps.Wide_Character_Set;
      Test   : in Membership;
      First  : out Positive;
      Last   : out Natural)
   is
   begin
      for J in Source'Range loop
         if Belongs (Source (J), Set, Test) then
            First := J;

            for K in J + 1 .. Source'Last loop
               if not Belongs (Source (K), Set, Test) then
                  Last := K - 1;
                  return;
               end if;
            end loop;

            --  Here if J indexes 1st char of token, and all chars
            --  after J are in the token

            Last := Source'Last;
            return;
         end if;
      end loop;

      --  Here if no token found

      First := Source'First;
      Last  := 0;
   end Find_Token;

   -----------
   -- Index --
   -----------

   function Index
     (Source   : in Wide_String;
      Pattern  : in Wide_String;
      Going    : in Direction := Forward;
      Mapping  : in Wide_Maps.Wide_Character_Mapping := Wide_Maps.Identity)
      return     Natural
   is
   begin
      if Pattern = "" then
         raise Pattern_Error;
      end if;

      --  Handle the case of non-identity mappings by creating a mapped
      --  string and making a recursive call using the identity mapping
      --  on this mapped string.

      if Mapping /= Identity then
         declare
            Mapped_Source : Wide_String (Source'Range);

         begin
            for J in Source'Range loop
               Mapped_Source (J) := Value (Mapping, Source (J));
            end loop;

            return Index (Mapped_Source, Pattern, Going);
         end;
      end if;

      if Going = Forward then
         for J in Source'First .. Source'Last - Pattern'Length + 1 loop
            if Pattern = Source (J .. J + Pattern'Length - 1) then
               return J;
            end if;
         end loop;

      else -- Going = Backward
         for J in reverse Source'First .. Source'Last - Pattern'Length + 1 loop
            if Pattern = Source (J .. J + Pattern'Length - 1) then
               return J;
            end if;
         end loop;
      end if;

      --  Fall through if no match found. Note that the loops are skipped
      --  completely in the case of the pattern being longer than the source.

      return 0;
   end Index;

   -----------
   -- Index --
   -----------

   function Index
     (Source   : in Wide_String;
      Pattern  : in Wide_String;
      Going    : in Direction := Forward;
      Mapping  : in Wide_Maps.Wide_Character_Mapping_Function)
      return     Natural
   is
      Mapped_Source : Wide_String (Source'Range);

   begin
      for J in Source'Range loop
         Mapped_Source (J) := Mapping (Source (J));
      end loop;

      return Index (Mapped_Source, Pattern, Going);
   end Index;

   function Index
     (Source : in Wide_String;
      Set    : in Wide_Maps.Wide_Character_Set;
      Test   : in Membership := Inside;
      Going  : in Direction  := Forward)
      return   Natural
   is
   begin
      if Going = Forward then
         for J in Source'Range loop
            if Belongs (Source (J), Set, Test) then
               return J;
            end if;
         end loop;

      else -- Going = Backward
         for J in reverse Source'Range loop
            if Belongs (Source (J), Set, Test) then
               return J;
            end if;
         end loop;
      end if;

      --  Fall through if no match

      return 0;
   end Index;

   ---------------------
   -- Index_Non_Blank --
   ---------------------

   function Index_Non_Blank
     (Source : in Wide_String;
      Going  : in Direction := Forward)
      return   Natural
   is
   begin
      if Going = Forward then
         for J in Source'Range loop
            if Source (J) /= Wide_Space then
               return J;
            end if;
         end loop;

      else -- Going = Backward
         for J in reverse Source'Range loop
            if Source (J) /= Wide_Space then
               return J;
            end if;
         end loop;
      end if;

      --  Fall through if no match

      return 0;

   end Index_Non_Blank;

end Ada.Strings.Wide_Search;
