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------------------------------------------------------------------------------
-- --
-- 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;
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