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1 | /* Subroutines for bison | |
2 | Copyright 1984, 1989, 2000 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 | /* Subroutines of file LR0.c. */ | |
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 PARAMS ((int n)); | |
31 | ||
32 | ||
33 | /* Given a vector of item numbers ITEMS, of length N, set up ruleset | |
34 | and itemset to indicate what rules could be run and which items | |
35 | could be accepted when those items are the active ones. | |
36 | ||
37 | ruleset contains a bit for each rule. closure sets the bits for | |
38 | all rules which could potentially describe the next input to be | |
39 | read. | |
40 | ||
41 | itemset is a vector of item numbers; itemsetend points to just | |
42 | beyond the end of the part of it that is significant. closure | |
43 | places there the indices of all items which represent units of | |
44 | input that could arrive next. */ | |
45 | ||
46 | void closure PARAMS ((short *items, int n)); | |
47 | ||
48 | ||
49 | /* Frees itemset, ruleset and internal data. */ | |
50 | ||
51 | void free_closure PARAMS ((void)); | |
52 | ||
53 | extern short *itemset; | |
54 | extern short *itemsetend; | |
55 | ||
56 | #endif /* !CLOSURE_H_ */ |