aboutsummaryrefslogtreecommitdiff
path: root/gcc/ada/s-htable.adb
blob: 9dbb7f98420178a08e28ca5566ed8671acf6ea0d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
------------------------------------------------------------------------------
--                                                                          --
--                         GNAT RUN-TIME COMPONENTS                         --
--                                                                          --
--                        S Y S T E M . H T A B L E                         --
--                                                                          --
--                                 B o d y                                  --
--                                                                          --
--                    Copyright (C) 1995-2007, 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 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,  51  Franklin  Street,  Fifth  Floor, --
-- Boston, MA 02110-1301, 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. --
-- Extensive contributions were provided by Ada Core Technologies Inc.      --
--                                                                          --
------------------------------------------------------------------------------

pragma Warnings (Off);
pragma Compiler_Unit;
pragma Warnings (On);

with Ada.Unchecked_Deallocation;

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;
         end if;

         Iterator_Ptr := Next (Iterator_Ptr);
         return Get_Non_Null;
      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;

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

   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;

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

      ----------
      -- 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 Rotate_Left (Value : Uns; Amount : Natural) return Uns;
      pragma Import (Intrinsic, Rotate_Left);

      Hash_Value : Uns;

   begin
      Hash_Value := 0;
      for J in Key'Range loop
         Hash_Value := Rotate_Left (Hash_Value, 3) + Character'Pos (Key (J));
      end loop;

      return Header_Num'First +
               Header_Num'Base (Hash_Value mod Header_Num'Range_Length);
   end Hash;

end System.HTable;