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1 | /* Subroutines for bison | |
2 | ||
3 | Copyright (C) 1984, 1989, 2000, 2001, 2002, 2007 Free Software | |
4 | Foundation, Inc. | |
5 | ||
6 | This file is part of Bison, the GNU Compiler Compiler. | |
7 | ||
8 | This program is free software: you can redistribute it and/or modify | |
9 | it under the terms of the GNU General Public License as published by | |
10 | the Free Software Foundation, either version 3 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | This program is distributed in the hope that it will be useful, | |
14 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | GNU General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License | |
19 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ | |
20 | ||
21 | #ifndef CLOSURE_H_ | |
22 | # define CLOSURE_H_ | |
23 | ||
24 | # include "gram.h" | |
25 | ||
26 | /* Allocates the itemset and ruleset vectors, and precomputes useful | |
27 | data so that closure can be called. n is the number of elements to | |
28 | allocate for itemset. */ | |
29 | ||
30 | void new_closure (unsigned int n); | |
31 | ||
32 | ||
33 | /* Given the kernel (aka core) of a state (a sorted vector of item numbers | |
34 | ITEMS, of length N), set up RULESET and ITEMSET to indicate what | |
35 | rules could be run and which items could be accepted when those | |
36 | items are the active ones. | |
37 | ||
38 | RULESET contains a bit for each rule. CLOSURE sets the bits for | |
39 | all rules which could potentially describe the next input to be | |
40 | read. | |
41 | ||
42 | ITEMSET is a sorted vector of item numbers; NITEMSET is its size | |
43 | (actually, points to just beyond the end of the part of it that is | |
44 | significant). CLOSURE places there the indices of all items which | |
45 | represent units of input that could arrive next. */ | |
46 | ||
47 | void closure (item_number *items, size_t n); | |
48 | ||
49 | ||
50 | /* Frees ITEMSET, RULESET and internal data. */ | |
51 | ||
52 | void free_closure (void); | |
53 | ||
54 | extern item_number *itemset; | |
55 | extern size_t nitemset; | |
56 | ||
57 | #endif /* !CLOSURE_H_ */ |