1 ------------------------------------------------------------------------------
3 -- GNAT RUNTIME COMPONENTS --
5 -- S Y S T E M . H T A B L E --
9 -- Copyright (C) 1995-2004 Ada Core Technologies, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 2, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
20 -- MA 02111-1307, USA. --
22 -- As a special exception, if other files instantiate generics from this --
23 -- unit, or you link this unit with other files to produce an executable, --
24 -- this unit does not by itself cause the resulting executable to be --
25 -- covered by the GNU General Public License. This exception does not --
26 -- however invalidate any other reasons why the executable file might be --
27 -- covered by the GNU Public License. --
29 -- GNAT was originally developed by the GNAT team at New York University. --
30 -- Extensive contributions were provided by Ada Core Technologies Inc. --
32 ------------------------------------------------------------------------------
34 with Ada.Unchecked_Deallocation;
36 package body System.HTable is
42 package body Static_HTable is
44 Table : array (Header_Num) of Elmt_Ptr;
46 Iterator_Index : Header_Num;
47 Iterator_Ptr : Elmt_Ptr;
48 Iterator_Started : Boolean := False;
50 function Get_Non_Null return Elmt_Ptr;
51 -- Returns Null_Ptr if Iterator_Started is false of the Table is
52 -- empty. Returns Iterator_Ptr if non null, or the next non null
53 -- element in table if any.
59 function Get (K : Key) return Elmt_Ptr is
63 Elmt := Table (Hash (K));
66 if Elmt = Null_Ptr then
69 elsif Equal (Get_Key (Elmt), K) then
82 function Get_First return Elmt_Ptr is
84 Iterator_Started := True;
85 Iterator_Index := Table'First;
86 Iterator_Ptr := Table (Iterator_Index);
94 function Get_Next return Elmt_Ptr is
96 if not Iterator_Started then
100 Iterator_Ptr := Next (Iterator_Ptr);
108 function Get_Non_Null return Elmt_Ptr is
110 while Iterator_Ptr = Null_Ptr loop
111 if Iterator_Index = Table'Last then
112 Iterator_Started := False;
116 Iterator_Index := Iterator_Index + 1;
117 Iterator_Ptr := Table (Iterator_Index);
127 procedure Remove (K : Key) is
128 Index : constant Header_Num := Hash (K);
130 Next_Elmt : Elmt_Ptr;
133 Elmt := Table (Index);
135 if Elmt = Null_Ptr then
138 elsif Equal (Get_Key (Elmt), K) then
139 Table (Index) := Next (Elmt);
143 Next_Elmt := Next (Elmt);
145 if Next_Elmt = Null_Ptr then
148 elsif Equal (Get_Key (Next_Elmt), K) then
149 Set_Next (Elmt, Next (Next_Elmt));
165 for J in Table'Range loop
166 Table (J) := Null_Ptr;
174 procedure Set (E : Elmt_Ptr) is
178 Index := Hash (Get_Key (E));
179 Set_Next (E, Table (Index));
189 package body Simple_HTable is
191 type Element_Wrapper;
192 type Elmt_Ptr is access all Element_Wrapper;
193 type Element_Wrapper is record
199 procedure Free is new
200 Ada.Unchecked_Deallocation (Element_Wrapper, Elmt_Ptr);
202 procedure Set_Next (E : Elmt_Ptr; Next : Elmt_Ptr);
203 function Next (E : Elmt_Ptr) return Elmt_Ptr;
204 function Get_Key (E : Elmt_Ptr) return Key;
206 package Tab is new Static_HTable (
207 Header_Num => Header_Num,
208 Element => Element_Wrapper,
209 Elmt_Ptr => Elmt_Ptr,
211 Set_Next => Set_Next,
222 function Get (K : Key) return Element is
223 Tmp : constant Elmt_Ptr := Tab.Get (K);
236 function Get_First return Element is
237 Tmp : constant Elmt_Ptr := Tab.Get_First;
250 function Get_Key (E : Elmt_Ptr) return Key is
259 function Get_Next return Element is
260 Tmp : constant Elmt_Ptr := Tab.Get_Next;
273 function Next (E : Elmt_Ptr) return Elmt_Ptr is
282 procedure Remove (K : Key) is
303 while E1 /= null loop
316 procedure Set (K : Key; E : Element) is
317 Tmp : constant Elmt_Ptr := Tab.Get (K);
320 Tab.Set (new Element_Wrapper'(K, E, null));
330 procedure Set_Next (E : Elmt_Ptr; Next : Elmt_Ptr) is
340 function Hash (Key : String) return Header_Num is
342 type Uns is mod 2 ** 32;
344 function Rotate_Left (Value : Uns; Amount : Natural) return Uns;
345 pragma Import (Intrinsic, Rotate_Left);
351 for J in Key'Range loop
352 Hash_Value := Rotate_Left (Hash_Value, 3) + Character'Pos (Key (J));
355 return Header_Num'First +
356 Header_Num'Base (Hash_Value mod Header_Num'Range_Length);