------------------------------------------------------------------------------ -- -- -- GNAT LIBRARY COMPONENTS -- -- -- -- ADA.CONTAINERS.HASH_TABLES.GENERIC_KEYS -- -- -- -- B o d y -- -- -- -- Copyright (C) 2004 Free Software Foundation, Inc. -- -- -- -- This specification is derived from the Ada Reference Manual for use with -- -- GNAT. The copyright notice above, and the license provisions that follow -- -- apply solely to the contents of the part following the private keyword. -- -- -- -- 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 2, 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. See the GNU General Public License -- -- for more details. You should have received a copy of the GNU General -- -- Public License distributed with GNAT; see 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 -- -- unit, or you link this unit with other files to produce an executable, -- -- this unit 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 Public License. -- -- -- -- This unit was originally developed by Matthew J Heaney. -- ------------------------------------------------------------------------------ package body Ada.Containers.Hash_Tables.Generic_Keys is -------------------------- -- Delete_Key_Sans_Free -- -------------------------- procedure Delete_Key_Sans_Free (HT : in out HT_Type; Key : Key_Type; X : out Node_Access) is Indx : Hash_Type; Prev : Node_Access; begin if HT.Length = 0 then X := Null_Node; return; end if; Indx := Index (HT, Key); X := HT.Buckets (Indx); if X = Null_Node then return; end if; if Equivalent_Keys (Key, X) then HT.Buckets (Indx) := Next (X); HT.Length := HT.Length - 1; return; end if; loop Prev := X; X := Next (Prev); if X = Null_Node then return; end if; if Equivalent_Keys (Key, X) then Set_Next (Node => Prev, Next => Next (X)); HT.Length := HT.Length - 1; return; end if; end loop; end Delete_Key_Sans_Free; ---------- -- Find -- ---------- function Find (HT : HT_Type; Key : Key_Type) return Node_Access is Indx : Hash_Type; Node : Node_Access; begin if HT.Length = 0 then return Null_Node; end if; Indx := Index (HT, Key); Node := HT.Buckets (Indx); while Node /= Null_Node loop if Equivalent_Keys (Key, Node) then return Node; end if; Node := Next (Node); end loop; return Null_Node; end Find; -------------------------------- -- Generic_Conditional_Insert -- -------------------------------- procedure Generic_Conditional_Insert (HT : in out HT_Type; Key : Key_Type; Node : out Node_Access; Success : out Boolean) is Indx : constant Hash_Type := Index (HT, Key); B : Node_Access renames HT.Buckets (Indx); subtype Length_Subtype is Count_Type range 0 .. Count_Type'Last - 1; begin if B = Null_Node then declare Length : constant Length_Subtype := HT.Length; begin Node := New_Node (Next => Null_Node); Success := True; B := Node; HT.Length := Length + 1; end; return; end if; Node := B; loop if Equivalent_Keys (Key, Node) then Success := False; return; end if; Node := Next (Node); exit when Node = Null_Node; end loop; declare Length : constant Length_Subtype := HT.Length; begin Node := New_Node (Next => B); Success := True; B := Node; HT.Length := Length + 1; end; end Generic_Conditional_Insert; ----------- -- Index -- ----------- function Index (HT : HT_Type; Key : Key_Type) return Hash_Type is begin return Hash (Key) mod HT.Buckets'Length; end Index; end Ada.Containers.Hash_Tables.Generic_Keys;