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1 | /* Subroutines for bison | |
2 | ||
3 | Copyright (C) 1984, 1989, 2000, 2001, 2002 Free Software | |
4 | Foundation, Inc. | |
5 | ||
6 | This file is part of Bison, the GNU Compiler Compiler. | |
7 | ||
8 | Bison is free software; you can redistribute it and/or modify it | |
9 | under the terms of the GNU General Public License as published by | |
10 | the Free Software Foundation; either version 2, or (at your option) | |
11 | any later version. | |
12 | ||
13 | Bison is distributed in the hope that it will be useful, but | |
14 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License | |
19 | along with Bison; see the file COPYING. If not, write to the Free | |
20 | Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA | |
21 | 02110-1301, USA. */ | |
22 | ||
23 | #ifndef CLOSURE_H_ | |
24 | # define CLOSURE_H_ | |
25 | ||
26 | # include "gram.h" | |
27 | ||
28 | /* Allocates the itemset and ruleset vectors, and precomputes useful | |
29 | data so that closure can be called. n is the number of elements to | |
30 | allocate for itemset. */ | |
31 | ||
32 | void new_closure (unsigned int n); | |
33 | ||
34 | ||
35 | /* Given the kernel (aka core) of a state (a vector of item numbers | |
36 | ITEMS, of length N), set up RULESET and ITEMSET to indicate what | |
37 | rules could be run and which items could be accepted when those | |
38 | items are the active ones. | |
39 | ||
40 | RULESET contains a bit for each rule. CLOSURE sets the bits for | |
41 | all rules which could potentially describe the next input to be | |
42 | read. | |
43 | ||
44 | ITEMSET is a vector of item numbers; NITEMSET is its size | |
45 | (actually, points to just beyond the end of the part of it that is | |
46 | significant). CLOSURE places there the indices of all items which | |
47 | represent units of input that could arrive next. */ | |
48 | ||
49 | void closure (item_number *items, size_t n); | |
50 | ||
51 | ||
52 | /* Frees ITEMSET, RULESET and internal data. */ | |
53 | ||
54 | void free_closure (void); | |
55 | ||
56 | extern item_number *itemset; | |
57 | extern size_t nitemset; | |
58 | ||
59 | #endif /* !CLOSURE_H_ */ |