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1/* Subroutines for bison
2 Copyright (C) 1984, 1989, 2000, 2001, 2002 Free Software Foundation, Inc.
3
4 This file is part of Bison, the GNU Compiler Compiler.
5
6 Bison is free software; you can redistribute it and/or modify it
7 under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
9 any later version.
10
11 Bison is distributed in the hope that it will be useful, but
12 WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 General Public License for more details.
15
16 You should have received a copy of the GNU General Public License
17 along with Bison; see the file COPYING. If not, write to the Free
18 Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
19 02111-1307, USA. */
20
21#ifndef CLOSURE_H_
22# define CLOSURE_H_
23
24/* Allocates the itemset and ruleset vectors, and precomputes useful
25 data so that closure can be called. n is the number of elements to
26 allocate for itemset. */
27
28void new_closure PARAMS ((int n));
29
30
31/* Given the kernel (aka core) of a state (a vector of item numbers
32 ITEMS, of length N), set up RULESET and ITEMSET to indicate what
33 rules could be run and which items could be accepted when those
34 items are the active ones.
35
36 RULESET contains a bit for each rule. CLOSURE sets the bits for
37 all rules which could potentially describe the next input to be
38 read.
39
40 ITEMSET is a vector of item numbers; NITEMSET is its size
41 (actually, points to just beyond the end of the part of it that is
42 significant). CLOSURE places there the indices of all items which
43 represent units of input that could arrive next. */
44
45void closure PARAMS ((item_number_t *items, int n));
46
47
48/* Frees ITEMSET, RULESET and internal data. */
49
50void free_closure PARAMS ((void));
51
52extern item_number_t *itemset;
53extern int nritemset;
54
55#endif /* !CLOSURE_H_ */