aboutsummaryrefslogtreecommitdiff
path: root/gcc/ada/elists.adb
blob: 0fb616e5cac042887e872ecf346ff6c76d84a48b (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
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
------------------------------------------------------------------------------
--                                                                          --
--                         GNAT COMPILER COMPONENTS                         --
--                                                                          --
--                               E L I S T S                                --
--                                                                          --
--                                 B o d y                                  --
--                                                                          --
--          Copyright (C) 1992-2006, 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,  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.      --
--                                                                          --
------------------------------------------------------------------------------

--  WARNING: There is a C version of this package. Any changes to this
--  source file must be properly reflected in the C header a-elists.h.

with Alloc;
with Debug;  use Debug;
with Output; use Output;
with Table;

package body Elists is

   -------------------------------------
   -- Implementation of Element Lists --
   -------------------------------------

   --  Element lists are composed of three types of entities. The element
   --  list header, which references the first and last elements of the
   --  list, the elements themselves which are singly linked and also
   --  reference the nodes on the list, and finally the nodes themselves.
   --  The following diagram shows how an element list is represented:

   --       +----------------------------------------------------+
   --       |  +------------------------------------------+      |
   --       |  |                                          |      |
   --       V  |                                          V      |
   --    +-----|--+    +-------+    +-------+         +-------+  |
   --    |  Elmt  |    |  1st  |    |  2nd  |         |  Last |  |
   --    |  List  |--->|  Elmt |--->|  Elmt  ---...-->|  Elmt ---+
   --    | Header |    |   |   |    |   |   |         |   |   |
   --    +--------+    +---|---+    +---|---+         +---|---+
   --                      |            |                 |
   --                      V            V                 V
   --                  +-------+    +-------+         +-------+
   --                  |       |    |       |         |       |
   --                  | Node1 |    | Node2 |         | Node3 |
   --                  |       |    |       |         |       |
   --                  +-------+    +-------+         +-------+

   --  The list header is an entry in the Elists table. The values used for
   --  the type Elist_Id are subscripts into this table. The First_Elmt field
   --  (Lfield1) points to the first element on the list, or to No_Elmt in the
   --  case of an empty list. Similarly the Last_Elmt field (Lfield2) points to
   --  the last element on the list or to No_Elmt in the case of an empty list.

   --  The elements themselves are entries in the Elmts table. The Next field
   --  of each entry points to the next element, or to the Elist header if this
   --  is the last item in the list. The Node field points to the node which
   --  is referenced by the corresponding list entry.

   -------------------------
   -- Element List Tables --
   -------------------------

   type Elist_Header is record
      First : Elmt_Id;
      Last  : Elmt_Id;
   end record;

   package Elists is new Table.Table (
     Table_Component_Type => Elist_Header,
     Table_Index_Type     => Elist_Id,
     Table_Low_Bound      => First_Elist_Id,
     Table_Initial        => Alloc.Elists_Initial,
     Table_Increment      => Alloc.Elists_Increment,
     Table_Name           => "Elists");

   type Elmt_Item is record
      Node : Node_Id;
      Next : Union_Id;
   end record;

   package Elmts is new Table.Table (
     Table_Component_Type => Elmt_Item,
     Table_Index_Type     => Elmt_Id,
     Table_Low_Bound      => First_Elmt_Id,
     Table_Initial        => Alloc.Elmts_Initial,
     Table_Increment      => Alloc.Elmts_Increment,
     Table_Name           => "Elmts");

   -----------------
   -- Append_Elmt --
   -----------------

   procedure Append_Elmt (Node : Node_Id; To : Elist_Id) is
      L : constant Elmt_Id := Elists.Table (To).Last;

   begin
      Elmts.Increment_Last;
      Elmts.Table (Elmts.Last).Node := Node;
      Elmts.Table (Elmts.Last).Next := Union_Id (To);

      if L = No_Elmt then
         Elists.Table (To).First := Elmts.Last;
      else
         Elmts.Table (L).Next := Union_Id (Elmts.Last);
      end if;

      Elists.Table (To).Last  := Elmts.Last;

      if Debug_Flag_N then
         Write_Str ("Append new element Elmt_Id = ");
         Write_Int (Int (Elmts.Last));
         Write_Str (" to list Elist_Id = ");
         Write_Int (Int (To));
         Write_Str (" referencing Node_Id = ");
         Write_Int (Int (Node));
         Write_Eol;
      end if;
   end Append_Elmt;

   --------------------
   -- Elists_Address --
   --------------------

   function Elists_Address return System.Address is
   begin
      return Elists.Table (First_Elist_Id)'Address;
   end Elists_Address;

   -------------------
   -- Elmts_Address --
   -------------------

   function Elmts_Address return System.Address is
   begin
      return Elmts.Table (First_Elmt_Id)'Address;
   end Elmts_Address;

   ----------------
   -- First_Elmt --
   ----------------

   function First_Elmt (List : Elist_Id) return Elmt_Id is
   begin
      pragma Assert (List > Elist_Low_Bound);
      return Elists.Table (List).First;
   end First_Elmt;

   ----------------
   -- Initialize --
   ----------------

   procedure Initialize is
   begin
      Elists.Init;
      Elmts.Init;
   end Initialize;

   -----------------------
   -- Insert_Elmt_After --
   -----------------------

   procedure Insert_Elmt_After (Node : Node_Id; Elmt : Elmt_Id) is
      N : constant Union_Id := Elmts.Table (Elmt).Next;

   begin
      pragma Assert (Elmt /= No_Elmt);

      Elmts.Increment_Last;
      Elmts.Table (Elmts.Last).Node := Node;
      Elmts.Table (Elmts.Last).Next := N;

      Elmts.Table (Elmt).Next := Union_Id (Elmts.Last);

      if N in Elist_Range then
         Elists.Table (Elist_Id (N)).Last := Elmts.Last;
      end if;
   end Insert_Elmt_After;

   ------------------------
   -- Is_Empty_Elmt_List --
   ------------------------

   function Is_Empty_Elmt_List (List : Elist_Id) return Boolean is
   begin
      return Elists.Table (List).First = No_Elmt;
   end Is_Empty_Elmt_List;

   -------------------
   -- Last_Elist_Id --
   -------------------

   function Last_Elist_Id return Elist_Id is
   begin
      return Elists.Last;
   end Last_Elist_Id;

   ---------------
   -- Last_Elmt --
   ---------------

   function Last_Elmt (List : Elist_Id) return Elmt_Id is
   begin
      return Elists.Table (List).Last;
   end Last_Elmt;

   ------------------
   -- Last_Elmt_Id --
   ------------------

   function Last_Elmt_Id return Elmt_Id is
   begin
      return Elmts.Last;
   end Last_Elmt_Id;

   ----------
   -- Lock --
   ----------

   procedure Lock is
   begin
      Elists.Locked := True;
      Elmts.Locked := True;
      Elists.Release;
      Elmts.Release;
   end Lock;

   -------------------
   -- New_Elmt_List --
   -------------------

   function New_Elmt_List return Elist_Id is
   begin
      Elists.Increment_Last;
      Elists.Table (Elists.Last).First := No_Elmt;
      Elists.Table (Elists.Last).Last  := No_Elmt;

      if Debug_Flag_N then
         Write_Str ("Allocate new element list, returned ID = ");
         Write_Int (Int (Elists.Last));
         Write_Eol;
      end if;

      return Elists.Last;
   end New_Elmt_List;

   ---------------
   -- Next_Elmt --
   ---------------

   function Next_Elmt (Elmt : Elmt_Id) return Elmt_Id is
      N : constant Union_Id := Elmts.Table (Elmt).Next;

   begin
      if N in Elist_Range then
         return No_Elmt;
      else
         return Elmt_Id (N);
      end if;
   end Next_Elmt;

   procedure Next_Elmt (Elmt : in out Elmt_Id) is
   begin
      Elmt := Next_Elmt (Elmt);
   end Next_Elmt;

   --------
   -- No --
   --------

   function No (List : Elist_Id) return Boolean is
   begin
      return List = No_Elist;
   end No;

   function No (Elmt : Elmt_Id) return Boolean is
   begin
      return Elmt = No_Elmt;
   end No;

   ----------
   -- Node --
   ----------

   function Node (Elmt : Elmt_Id) return Node_Or_Entity_Id is
   begin
      if Elmt = No_Elmt then
         return Empty;
      else
         return Elmts.Table (Elmt).Node;
      end if;
   end Node;

   ----------------
   -- Num_Elists --
   ----------------

   function Num_Elists return Nat is
   begin
      return Int (Elmts.Last) - Int (Elmts.First) + 1;
   end Num_Elists;

   ------------------
   -- Prepend_Elmt --
   ------------------

   procedure Prepend_Elmt (Node : Node_Id; To : Elist_Id) is
      F : constant Elmt_Id := Elists.Table (To).First;

   begin
      Elmts.Increment_Last;
      Elmts.Table (Elmts.Last).Node := Node;

      if F = No_Elmt then
         Elists.Table (To).Last := Elmts.Last;
         Elmts.Table (Elmts.Last).Next := Union_Id (To);
      else
         Elmts.Table (Elmts.Last).Next := Union_Id (F);
      end if;

      Elists.Table (To).First  := Elmts.Last;

   end Prepend_Elmt;

   -------------
   -- Present --
   -------------

   function Present (List : Elist_Id) return Boolean is
   begin
      return List /= No_Elist;
   end Present;

   function Present (Elmt : Elmt_Id) return Boolean is
   begin
      return Elmt /= No_Elmt;
   end Present;

   -----------------
   -- Remove_Elmt --
   -----------------

   procedure Remove_Elmt (List : Elist_Id; Elmt : Elmt_Id) is
      Nxt : Elmt_Id;
      Prv : Elmt_Id;

   begin
      Nxt := Elists.Table (List).First;

      --  Case of removing only element in the list

      if Elmts.Table (Nxt).Next in Elist_Range then

         pragma Assert (Nxt = Elmt);

         Elists.Table (List).First := No_Elmt;
         Elists.Table (List).Last  := No_Elmt;

      --  Case of removing the first element in the list

      elsif Nxt = Elmt then
         Elists.Table (List).First := Elmt_Id (Elmts.Table (Nxt).Next);

      --  Case of removing second or later element in the list

      else
         loop
            Prv := Nxt;
            Nxt := Elmt_Id (Elmts.Table (Prv).Next);
            exit when Nxt = Elmt
              or else Elmts.Table (Nxt).Next in Elist_Range;
         end loop;

         pragma Assert (Nxt = Elmt);

         Elmts.Table (Prv).Next := Elmts.Table (Nxt).Next;

         if Elmts.Table (Prv).Next in Elist_Range then
            Elists.Table (List).Last := Prv;
         end if;
      end if;
   end Remove_Elmt;

   ----------------------
   -- Remove_Last_Elmt --
   ----------------------

   procedure Remove_Last_Elmt (List : Elist_Id) is
      Nxt : Elmt_Id;
      Prv : Elmt_Id;

   begin
      Nxt := Elists.Table (List).First;

      --  Case of removing only element in the list

      if Elmts.Table (Nxt).Next in Elist_Range then
         Elists.Table (List).First := No_Elmt;
         Elists.Table (List).Last  := No_Elmt;

      --  Case of at least two elements in list

      else
         loop
            Prv := Nxt;
            Nxt := Elmt_Id (Elmts.Table (Prv).Next);
            exit when Elmts.Table (Nxt).Next in Elist_Range;
         end loop;

         Elmts.Table (Prv).Next   := Elmts.Table (Nxt).Next;
         Elists.Table (List).Last := Prv;
      end if;
   end Remove_Last_Elmt;

   ------------------
   -- Replace_Elmt --
   ------------------

   procedure Replace_Elmt (Elmt : Elmt_Id; New_Node : Node_Id) is
   begin
      Elmts.Table (Elmt).Node := New_Node;
   end Replace_Elmt;

   ---------------
   -- Tree_Read --
   ---------------

   procedure Tree_Read is
   begin
      Elists.Tree_Read;
      Elmts.Tree_Read;
   end Tree_Read;

   ----------------
   -- Tree_Write --
   ----------------

   procedure Tree_Write is
   begin
      Elists.Tree_Write;
      Elmts.Tree_Write;
   end Tree_Write;

end Elists;