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------------------------------------------------------------------------------
-- --
-- GNAT RUN-TIME COMPONENTS --
-- --
-- S Y S T E M . H T A B L E --
-- --
-- B o d y --
-- --
-- Copyright (C) 1995-2022, AdaCore --
-- --
-- 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 3, 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. --
-- --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception, --
-- version 3.1, as published by the Free Software Foundation. --
-- --
-- You should have received a copy of the GNU General Public License and --
-- a copy of the GCC Runtime Library Exception along with this program; --
-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
-- <http://www.gnu.org/licenses/>. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
with Ada.Unchecked_Deallocation;
with System.String_Hash;
package body System.HTable is
-------------------
-- Static_HTable --
-------------------
package body Static_HTable is
Table : array (Header_Num) of Elmt_Ptr;
Iterator_Index : Header_Num;
Iterator_Ptr : Elmt_Ptr;
Iterator_Started : Boolean := False;
function Get_Non_Null return Elmt_Ptr;
-- Returns Null_Ptr if Iterator_Started is false or the Table is empty.
-- Returns Iterator_Ptr if non null, or the next non null element in
-- table if any.
---------
-- 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;
---------------
-- Get_First --
---------------
function Get_First return Elmt_Ptr is
begin
Iterator_Started := True;
Iterator_Index := Table'First;
Iterator_Ptr := Table (Iterator_Index);
return Get_Non_Null;
end Get_First;
--------------
-- Get_Next --
--------------
function Get_Next return Elmt_Ptr is
begin
if not Iterator_Started then
return Null_Ptr;
else
Iterator_Ptr := Next (Iterator_Ptr);
return Get_Non_Null;
end if;
end Get_Next;
------------------
-- Get_Non_Null --
------------------
function Get_Non_Null return Elmt_Ptr is
begin
while Iterator_Ptr = Null_Ptr loop
if Iterator_Index = Table'Last then
Iterator_Started := False;
return Null_Ptr;
end if;
Iterator_Index := Iterator_Index + 1;
Iterator_Ptr := Table (Iterator_Index);
end loop;
return Iterator_Ptr;
end Get_Non_Null;
-------------
-- Present --
-------------
function Present (K : Key) return Boolean is
begin
return Get (K) /= Null_Ptr;
end Present;
------------
-- 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;
-----------
-- Reset --
-----------
procedure Reset is
begin
-- Use an aggregate for efficiency reasons
Table := [others => Null_Ptr];
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;
------------------------
-- Set_If_Not_Present --
------------------------
function Set_If_Not_Present (E : Elmt_Ptr) return Boolean is
K : Key renames Get_Key (E);
-- Note that it is important to use a renaming here rather than
-- define a constant initialized by the call, because the latter
-- construct runs into bootstrap problems with earlier versions
-- of the GNAT compiler.
Index : constant Header_Num := Hash (K);
Elmt : Elmt_Ptr;
begin
Elmt := Table (Index);
loop
if Elmt = Null_Ptr then
Set_Next (E, Table (Index));
Table (Index) := E;
return True;
elsif Equal (Get_Key (Elmt), K) then
return False;
else
Elmt := Next (Elmt);
end if;
end loop;
end Set_If_Not_Present;
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 Free is new
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;
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);
---------
-- Get --
---------
function Get (K : Key) return Element is
Tmp : constant Elmt_Ptr := Tab.Get (K);
begin
if Tmp = null then
return No_Element;
else
return Tmp.E;
end if;
end Get;
---------------
-- Get_First --
---------------
function Get_First return Element is
Tmp : constant Elmt_Ptr := Tab.Get_First;
begin
if Tmp = null then
return No_Element;
else
return Tmp.E;
end if;
end Get_First;
procedure Get_First (K : in out Key; E : out Element) is
Tmp : constant Elmt_Ptr := Tab.Get_First;
begin
if Tmp = null then
E := No_Element;
else
K := Tmp.K;
E := Tmp.E;
end if;
end Get_First;
-------------
-- Get_Key --
-------------
function Get_Key (E : Elmt_Ptr) return Key is
begin
return E.K;
end Get_Key;
--------------
-- Get_Next --
--------------
function Get_Next return Element is
Tmp : constant Elmt_Ptr := Tab.Get_Next;
begin
if Tmp = null then
return No_Element;
else
return Tmp.E;
end if;
end Get_Next;
procedure Get_Next (K : in out Key; E : out Element) is
Tmp : constant Elmt_Ptr := Tab.Get_Next;
begin
if Tmp = null then
E := No_Element;
else
K := Tmp.K;
E := Tmp.E;
end if;
end Get_Next;
----------
-- Next --
----------
function Next (E : Elmt_Ptr) return Elmt_Ptr is
begin
return E.Next;
end Next;
------------
-- Remove --
------------
procedure Remove (K : Key) is
Tmp : Elmt_Ptr;
begin
Tmp := Tab.Get (K);
if Tmp /= null then
Tab.Remove (K);
Free (Tmp);
end if;
end Remove;
-----------
-- Reset --
-----------
procedure Reset is
E1, E2 : Elmt_Ptr;
begin
E1 := Tab.Get_First;
while E1 /= null loop
E2 := Tab.Get_Next;
Free (E1);
E1 := E2;
end loop;
Tab.Reset;
end Reset;
---------
-- Set --
---------
procedure Set (K : Key; E : Element) is
Tmp : constant 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;
--------------
-- Set_Next --
--------------
procedure Set_Next (E : Elmt_Ptr; Next : Elmt_Ptr) is
begin
E.Next := Next;
end Set_Next;
end Simple_HTable;
----------
-- Hash --
----------
function Hash (Key : String) return Header_Num is
type Uns is mod 2 ** 32;
function Hash_Fun is
new System.String_Hash.Hash (Character, String, Uns);
begin
return Header_Num'First +
Header_Num'Base (Hash_Fun (Key) mod Header_Num'Range_Length);
end Hash;
end System.HTable;
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