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/* Subroutines for bison
Copyright (C) 1984, 1989, 2000-2002, 2007, 2009-2015, 2018-2019 Free
Software Foundation, Inc.
This file is part of Bison, the GNU Compiler Compiler.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT 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
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#ifndef CLOSURE_H_
# define CLOSURE_H_
# include "gram.h"
/* Allocates the itemset and ruleset vectors, and precomputes useful
data so that closure can be called. n is the number of elements to
allocate for itemset. */
void new_closure (unsigned n);
/* Given the kernel (aka core) of a state (a sorted vector of item numbers
ITEMS, of length N), set up RULESET and ITEMSET to indicate what
rules could be run and which items could be accepted when those
items are the active ones.
RULESET contains a bit for each rule. CLOSURE sets the bits for
all rules which could potentially describe the next input to be
read.
ITEMSET is a sorted vector of item numbers; NITEMSET is its size
(actually, points to just beyond the end of the part of it that is
significant). CLOSURE places there the indices of all items which
represent units of input that could arrive next. */
void closure (item_number const *items, size_t n);
/* Frees ITEMSET, RULESET and internal data. */
void free_closure (void);
extern item_number *itemset;
extern size_t nitemset;
#endif /* !CLOSURE_H_ */
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