1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2009, Free Software Foundation, 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 3, 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. --
18 -- As a special exception under Section 7 of GPL version 3, you are granted --
19 -- additional permissions described in the GCC Runtime Library Exception, --
20 -- version 3.1, as published by the Free Software Foundation. --
22 -- You should have received a copy of the GNU General Public License and --
23 -- a copy of the GCC Runtime Library Exception along with this program; --
24 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
25 -- <http://www.gnu.org/licenses/>. --
27 -- GNAT was originally developed by the GNAT team at New York University. --
28 -- Extensive contributions were provided by Ada Core Technologies Inc. --
30 ------------------------------------------------------------------------------
32 -- WARNING: There is a C version of this package. Any changes to this
33 -- source file must be properly reflected in the C header a-elists.h.
36 with Debug; use Debug;
37 with Output; use Output;
40 package body Elists is
42 -------------------------------------
43 -- Implementation of Element Lists --
44 -------------------------------------
46 -- Element lists are composed of three types of entities. The element
47 -- list header, which references the first and last elements of the
48 -- list, the elements themselves which are singly linked and also
49 -- reference the nodes on the list, and finally the nodes themselves.
50 -- The following diagram shows how an element list is represented:
52 -- +----------------------------------------------------+
53 -- | +------------------------------------------+ |
56 -- +-----|--+ +-------+ +-------+ +-------+ |
57 -- | Elmt | | 1st | | 2nd | | Last | |
58 -- | List |--->| Elmt |--->| Elmt ---...-->| Elmt ---+
59 -- | Header | | | | | | | | | |
60 -- +--------+ +---|---+ +---|---+ +---|---+
63 -- +-------+ +-------+ +-------+
65 -- | Node1 | | Node2 | | Node3 |
67 -- +-------+ +-------+ +-------+
69 -- The list header is an entry in the Elists table. The values used for
70 -- the type Elist_Id are subscripts into this table. The First_Elmt field
71 -- (Lfield1) points to the first element on the list, or to No_Elmt in the
72 -- case of an empty list. Similarly the Last_Elmt field (Lfield2) points to
73 -- the last element on the list or to No_Elmt in the case of an empty list.
75 -- The elements themselves are entries in the Elmts table. The Next field
76 -- of each entry points to the next element, or to the Elist header if this
77 -- is the last item in the list. The Node field points to the node which
78 -- is referenced by the corresponding list entry.
80 -------------------------
81 -- Element List Tables --
82 -------------------------
84 type Elist_Header is record
89 package Elists is new Table.Table (
90 Table_Component_Type => Elist_Header,
91 Table_Index_Type => Elist_Id'Base,
92 Table_Low_Bound => First_Elist_Id,
93 Table_Initial => Alloc.Elists_Initial,
94 Table_Increment => Alloc.Elists_Increment,
95 Table_Name => "Elists");
97 type Elmt_Item is record
98 Node : Node_Or_Entity_Id;
102 package Elmts is new Table.Table (
103 Table_Component_Type => Elmt_Item,
104 Table_Index_Type => Elmt_Id'Base,
105 Table_Low_Bound => First_Elmt_Id,
106 Table_Initial => Alloc.Elmts_Initial,
107 Table_Increment => Alloc.Elmts_Increment,
108 Table_Name => "Elmts");
114 procedure Append_Elmt (N : Node_Or_Entity_Id; To : Elist_Id) is
115 L : constant Elmt_Id := Elists.Table (To).Last;
118 Elmts.Increment_Last;
119 Elmts.Table (Elmts.Last).Node := N;
120 Elmts.Table (Elmts.Last).Next := Union_Id (To);
123 Elists.Table (To).First := Elmts.Last;
125 Elmts.Table (L).Next := Union_Id (Elmts.Last);
128 Elists.Table (To).Last := Elmts.Last;
131 Write_Str ("Append new element Elmt_Id = ");
132 Write_Int (Int (Elmts.Last));
133 Write_Str (" to list Elist_Id = ");
134 Write_Int (Int (To));
135 Write_Str (" referencing Node_Or_Entity_Id = ");
141 ------------------------
142 -- Append_Unique_Elmt --
143 ------------------------
145 procedure Append_Unique_Elmt (N : Node_Or_Entity_Id; To : Elist_Id) is
148 Elmt := First_Elmt (To);
153 elsif Node (Elmt) = N then
159 end Append_Unique_Elmt;
165 function Elists_Address return System.Address is
167 return Elists.Table (First_Elist_Id)'Address;
174 function Elmts_Address return System.Address is
176 return Elmts.Table (First_Elmt_Id)'Address;
183 function First_Elmt (List : Elist_Id) return Elmt_Id is
185 pragma Assert (List > Elist_Low_Bound);
186 return Elists.Table (List).First;
193 procedure Initialize is
199 -----------------------
200 -- Insert_Elmt_After --
201 -----------------------
203 procedure Insert_Elmt_After (N : Node_Or_Entity_Id; Elmt : Elmt_Id) is
204 Nxt : constant Union_Id := Elmts.Table (Elmt).Next;
207 pragma Assert (Elmt /= No_Elmt);
209 Elmts.Increment_Last;
210 Elmts.Table (Elmts.Last).Node := N;
211 Elmts.Table (Elmts.Last).Next := Nxt;
213 Elmts.Table (Elmt).Next := Union_Id (Elmts.Last);
215 if Nxt in Elist_Range then
216 Elists.Table (Elist_Id (Nxt)).Last := Elmts.Last;
218 end Insert_Elmt_After;
220 ------------------------
221 -- Is_Empty_Elmt_List --
222 ------------------------
224 function Is_Empty_Elmt_List (List : Elist_Id) return Boolean is
226 return Elists.Table (List).First = No_Elmt;
227 end Is_Empty_Elmt_List;
233 function Last_Elist_Id return Elist_Id is
242 function Last_Elmt (List : Elist_Id) return Elmt_Id is
244 return Elists.Table (List).Last;
251 function Last_Elmt_Id return Elmt_Id is
262 Elists.Locked := True;
263 Elmts.Locked := True;
272 function New_Elmt_List return Elist_Id is
274 Elists.Increment_Last;
275 Elists.Table (Elists.Last).First := No_Elmt;
276 Elists.Table (Elists.Last).Last := No_Elmt;
279 Write_Str ("Allocate new element list, returned ID = ");
280 Write_Int (Int (Elists.Last));
291 function Next_Elmt (Elmt : Elmt_Id) return Elmt_Id is
292 N : constant Union_Id := Elmts.Table (Elmt).Next;
295 if N in Elist_Range then
302 procedure Next_Elmt (Elmt : in out Elmt_Id) is
304 Elmt := Next_Elmt (Elmt);
311 function No (List : Elist_Id) return Boolean is
313 return List = No_Elist;
316 function No (Elmt : Elmt_Id) return Boolean is
318 return Elmt = No_Elmt;
325 function Node (Elmt : Elmt_Id) return Node_Or_Entity_Id is
327 if Elmt = No_Elmt then
330 return Elmts.Table (Elmt).Node;
338 function Num_Elists return Nat is
340 return Int (Elmts.Last) - Int (Elmts.First) + 1;
347 procedure Prepend_Elmt (N : Node_Or_Entity_Id; To : Elist_Id) is
348 F : constant Elmt_Id := Elists.Table (To).First;
351 Elmts.Increment_Last;
352 Elmts.Table (Elmts.Last).Node := N;
355 Elists.Table (To).Last := Elmts.Last;
356 Elmts.Table (Elmts.Last).Next := Union_Id (To);
358 Elmts.Table (Elmts.Last).Next := Union_Id (F);
361 Elists.Table (To).First := Elmts.Last;
368 function Present (List : Elist_Id) return Boolean is
370 return List /= No_Elist;
373 function Present (Elmt : Elmt_Id) return Boolean is
375 return Elmt /= No_Elmt;
382 procedure Remove_Elmt (List : Elist_Id; Elmt : Elmt_Id) is
387 Nxt := Elists.Table (List).First;
389 -- Case of removing only element in the list
391 if Elmts.Table (Nxt).Next in Elist_Range then
393 pragma Assert (Nxt = Elmt);
395 Elists.Table (List).First := No_Elmt;
396 Elists.Table (List).Last := No_Elmt;
398 -- Case of removing the first element in the list
400 elsif Nxt = Elmt then
401 Elists.Table (List).First := Elmt_Id (Elmts.Table (Nxt).Next);
403 -- Case of removing second or later element in the list
408 Nxt := Elmt_Id (Elmts.Table (Prv).Next);
410 or else Elmts.Table (Nxt).Next in Elist_Range;
413 pragma Assert (Nxt = Elmt);
415 Elmts.Table (Prv).Next := Elmts.Table (Nxt).Next;
417 if Elmts.Table (Prv).Next in Elist_Range then
418 Elists.Table (List).Last := Prv;
423 ----------------------
424 -- Remove_Last_Elmt --
425 ----------------------
427 procedure Remove_Last_Elmt (List : Elist_Id) is
432 Nxt := Elists.Table (List).First;
434 -- Case of removing only element in the list
436 if Elmts.Table (Nxt).Next in Elist_Range then
437 Elists.Table (List).First := No_Elmt;
438 Elists.Table (List).Last := No_Elmt;
440 -- Case of at least two elements in list
445 Nxt := Elmt_Id (Elmts.Table (Prv).Next);
446 exit when Elmts.Table (Nxt).Next in Elist_Range;
449 Elmts.Table (Prv).Next := Elmts.Table (Nxt).Next;
450 Elists.Table (List).Last := Prv;
452 end Remove_Last_Elmt;
458 procedure Replace_Elmt (Elmt : Elmt_Id; New_Node : Node_Or_Entity_Id) is
460 Elmts.Table (Elmt).Node := New_Node;
467 procedure Tree_Read is
477 procedure Tree_Write is
489 Elists.Locked := False;
490 Elmts.Locked := False;