File : g-htable.adb
------------------------------------------------------------------------------
-- --
-- GNAT RUNTIME COMPONENTS --
-- --
5 -- G N A T . H T A B L E --
-- --
-- B o d y --
-- --
-- $Revision: 1.14 $
10 -- --
-- Copyright (C) 1995-1999 Ada Core Technologies, 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- --
15 -- 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 --
20 -- 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 --
25 -- 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. --
30 -- --
-- GNAT is maintained by Ada Core Technologies Inc (http://www.gnat.com). --
-- --
------------------------------------------------------------------------------
35 with Ada.Unchecked_Deallocation;
package body GNAT.HTable is
--------------------
-- Static_HTable --
40 --------------------
package body Static_HTable is
Table : array (Header_Num) of Elmt_Ptr;
45
Iterator_Index : Header_Num;
Iterator_Ptr : Elmt_Ptr;
Iterator_Started : Boolean := False;
50 function Get_Non_Null return Elmt_Ptr;
-- Returns Null_Ptr if Iterator_Started is false of the Table is
-- empty. Returns Iterator_Ptr if non null, or the next non null
-- element in table if any.
55 ---------
-- Get --
---------
function Get (K : Key) return Elmt_Ptr is
60 Elmt : Elmt_Ptr;
begin
Elmt := Table (Hash (K));
65 loop
if Elmt = Null_Ptr then
return Null_Ptr;
elsif Equal (Get_Key (Elmt), K) then
70 return Elmt;
else
Elmt := Next (Elmt);
end if;
75 end loop;
end Get;
---------------
-- Get_First --
80 ---------------
function Get_First return Elmt_Ptr is
begin
Iterator_Started := True;
85 Iterator_Index := Table'First;
Iterator_Ptr := Table (Iterator_Index);
return Get_Non_Null;
end Get_First;
90 --------------
-- Get_Next --
--------------
function Get_Next return Elmt_Ptr is
95 begin
if not Iterator_Started then
return Null_Ptr;
end if;
100 Iterator_Ptr := Next (Iterator_Ptr);
return Get_Non_Null;
end Get_Next;
------------------
105 -- Get_Non_Null --
------------------
function Get_Non_Null return Elmt_Ptr is
begin
110 while Iterator_Ptr = Null_Ptr loop
if Iterator_Index = Table'Last then
Iterator_Started := False;
return Null_Ptr;
end if;
115
Iterator_Index := Iterator_Index + 1;
Iterator_Ptr := Table (Iterator_Index);
end loop;
120 return Iterator_Ptr;
end Get_Non_Null;
------------
-- Remove --
125 ------------
procedure Remove (K : Key) is
Index : constant Header_Num := Hash (K);
Elmt : Elmt_Ptr;
130 Next_Elmt : Elmt_Ptr;
begin
Elmt := Table (Index);
135 if Elmt = Null_Ptr then
return;
elsif Equal (Get_Key (Elmt), K) then
Table (Index) := Next (Elmt);
140
else
loop
Next_Elmt := Next (Elmt);
145 if Next_Elmt = Null_Ptr then
return;
elsif Equal (Get_Key (Next_Elmt), K) then
Set_Next (Elmt, Next (Next_Elmt));
150 return;
else
Elmt := Next_Elmt;
end if;
155 end loop;
end if;
end Remove;
-----------
160 -- Reset --
-----------
procedure Reset is
begin
165 for J in Table'Range loop
Table (J) := Null_Ptr;
end loop;
end Reset;
170 ---------
-- Set --
---------
procedure Set (E : Elmt_Ptr) is
175 Index : Header_Num;
begin
Index := Hash (Get_Key (E));
Set_Next (E, Table (Index));
180 Table (Index) := E;
end Set;
end Static_HTable;
185 --------------------
-- Simple_HTable --
--------------------
package body Simple_HTable is
190
type Element_Wrapper;
type Elmt_Ptr is access all Element_Wrapper;
type Element_Wrapper is record
K : Key;
195 E : Element;
Next : Elmt_Ptr;
end record;
procedure Free is new
200 Ada.Unchecked_Deallocation (Element_Wrapper, Elmt_Ptr);
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;
205
package Tab is new Static_HTable (
Header_Num => Header_Num,
Element => Element_Wrapper,
Elmt_Ptr => Elmt_Ptr,
210 Null_Ptr => null,
Set_Next => Set_Next,
Next => Next,
Key => Key,
Get_Key => Get_Key,
215 Hash => Hash,
Equal => Equal);
---------
-- Get --
220 ---------
function Get (K : Key) return Element is
Tmp : constant Elmt_Ptr := Tab.Get (K);
225 begin
if Tmp = null then
return No_Element;
else
return Tmp.E;
230 end if;
end Get;
---------------
-- Get_First --
235 ---------------
function Get_First return Element is
Tmp : constant Elmt_Ptr := Tab.Get_First;
240 begin
if Tmp = null then
return No_Element;
else
return Tmp.E;
245 end if;
end Get_First;
-------------
-- Get_Key --
250 -------------
function Get_Key (E : Elmt_Ptr) return Key is
begin
return E.K;
255 end Get_Key;
--------------
-- Get_Next --
--------------
260
function Get_Next return Element is
Tmp : constant Elmt_Ptr := Tab.Get_Next;
begin
265 if Tmp = null then
return No_Element;
else
return Tmp.E;
end if;
270 end Get_Next;
----------
-- Next --
----------
275
function Next (E : Elmt_Ptr) return Elmt_Ptr is
begin
return E.Next;
end Next;
280
------------
-- Remove --
------------
285 procedure Remove (K : Key) is
Tmp : Elmt_Ptr;
begin
Tmp := Tab.Get (K);
290
if Tmp /= null then
Tab.Remove (K);
Free (Tmp);
end if;
295 end Remove;
-----------
-- Reset --
-----------
300
procedure Reset is
E1, E2 : Elmt_Ptr;
begin
305 E1 := Tab.Get_First;
while E1 /= null loop
E2 := Tab.Get_Next;
Free (E1);
E1 := E2;
310 end loop;
Tab.Reset;
end Reset;
315 ---------
-- Set --
---------
procedure Set (K : Key; E : Element) is
320 Tmp : constant Elmt_Ptr := Tab.Get (K);
begin
if Tmp = null then
Tab.Set (new Element_Wrapper'(K, E, null));
325 else
Tmp.E := E;
end if;
end Set;
330 --------------
-- Set_Next --
--------------
procedure Set_Next (E : Elmt_Ptr; Next : Elmt_Ptr) is
335 begin
E.Next := Next;
end Set_Next;
end Simple_HTable;
340 ----------
-- Hash --
----------
function Hash (Key : String) return Header_Num is
345
type Uns is mod 2 ** 32;
function Rotate_Left (Value : Uns; Amount : Natural) return Uns;
pragma Import (Intrinsic, Rotate_Left);
350
Tmp : Uns := 0;
begin
for J in Key'Range loop
355 Tmp := Rotate_Left (Tmp, 1) + Character'Pos (Key (J));
end loop;
return Header_Num'First +
Header_Num'Base (Tmp mod Header_Num'Range_Length);
360 end Hash;
end GNAT.HTable;