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------------------------------------------------------------------------------
-- --
-- GNAT RUNTIME COMPONENTS --
-- --
-- G N A T . H T A B L E --
-- --
-- B o d y --
-- --
-- $Revision: 1.6 $ --
-- --
-- Copyright (C) 1992-1997 Free Software Foundation, Inc. --
-- --
-- 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. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
-- --
------------------------------------------------------------------------------
package body GNAT.HTable is
--------------------
-- Static_HTable --
--------------------
package body Static_HTable is
Table : array (Header_Num) of Elmt_Ptr;
-----------
-- Reset --
-----------
procedure Reset is
begin
for J in Table'Range loop
Table (J) := Null_Ptr;
end loop;
end Reset;
---------
-- Set --
---------
procedure Set (E : Elmt_Ptr) is
Index : Header_Num;
begin
Index := Hash (Get_Key (E));
Set_Next (E, Table (Index));
Table (Index) := E;
end Set;
---------
-- Get --
---------
function Get (K : Key) return Elmt_Ptr is
Elmt : Elmt_Ptr;
begin
Elmt := Table (Hash (K));
loop
if Elmt = Null_Ptr then
return Null_Ptr;
elsif Equal (Get_Key (Elmt), K) then
return Elmt;
else
Elmt := Next (Elmt);
end if;
end loop;
end Get;
------------
-- Remove --
------------
procedure Remove (K : Key) is
Index : constant Header_Num := Hash (K);
Elmt : Elmt_Ptr;
Next_Elmt : Elmt_Ptr;
begin
Elmt := Table (Index);
if Elmt = Null_Ptr then
return;
elsif Equal (Get_Key (Elmt), K) then
Table (Index) := Next (Elmt);
else
loop
Next_Elmt := Next (Elmt);
if Next_Elmt = Null_Ptr then
return;
elsif Equal (Get_Key (Next_Elmt), K) then
Set_Next (Elmt, Next (Next_Elmt));
return;
else
Elmt := Next_Elmt;
end if;
end loop;
end if;
end Remove;
end Static_HTable;
--------------------
-- Simple_HTable --
--------------------
package body Simple_HTable is
type Element_Wrapper;
type Elmt_Ptr is access all Element_Wrapper;
type Element_Wrapper is record
K : Key;
E : Element;
Next : Elmt_Ptr;
end record;
procedure Set_Next (E : Elmt_Ptr; Next : Elmt_Ptr);
function Next (E : Elmt_Ptr) return Elmt_Ptr;
function Get_Key (E : Elmt_Ptr) return Key;
package Tab is new Static_HTable (
Header_Num => Header_Num,
Element => Element_Wrapper,
Elmt_Ptr => Elmt_Ptr,
Null_Ptr => null,
Set_Next => Set_Next,
Next => Next,
Key => Key,
Get_Key => Get_Key,
Hash => Hash,
Equal => Equal);
procedure Set_Next (E : Elmt_Ptr; Next : Elmt_Ptr) is
begin
E.Next := Next;
end Set_Next;
function Next (E : Elmt_Ptr) return Elmt_Ptr is
begin
return E.Next;
end Next;
function Get_Key (E : Elmt_Ptr) return Key is
begin
return E.K;
end Get_Key;
procedure Set (K : Key; E : Element) is
Tmp : Elmt_Ptr := Tab.Get (K);
begin
if Tmp = null then
Tab.Set (new Element_Wrapper'(K, E, null));
else
Tmp.E := E;
end if;
end Set;
function Get (K : Key) return Element is
Tmp : Elmt_Ptr := Tab.Get (K);
begin
if Tmp = null then
return No_Element;
else
return Tab.Get (K).E;
end if;
end Get;
end Simple_HTable;
----------
-- Hash --
----------
function Hash (Key : String) return Header_Num is
type S is mod 2**8;
Size : constant S := S (Header_Num'Last - Header_Num'First + 1);
Tmp : S := 0;
begin
for J in Key'Range loop
Tmp := Tmp xor S (Character'Pos (Key (J)));
end loop;
return Header_Num'First + Header_Num'Base (Tmp mod Size);
end Hash;
end GNAT.HTable;
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