/contrib/byacc/closure.c
C | 251 lines | 211 code | 39 blank | 1 comment | 31 complexity | 0068390aabee17d45f5cb07275ae1e2a MD5 | raw file
Possible License(s): MPL-2.0-no-copyleft-exception, BSD-3-Clause, LGPL-2.0, LGPL-2.1, BSD-2-Clause, 0BSD, JSON, AGPL-1.0, GPL-2.0
- /* $Id: closure.c,v 1.9 2010/06/09 08:21:47 tom Exp $ */
- #include "defs.h"
- Value_t *itemset;
- Value_t *itemsetend;
- unsigned *ruleset;
- static unsigned *first_derives;
- static unsigned *EFF;
- static void
- set_EFF(void)
- {
- unsigned *row;
- int symbol;
- short *sp;
- int rowsize;
- int i;
- int rule;
- rowsize = WORDSIZE(nvars);
- EFF = NEW2(nvars * rowsize, unsigned);
- row = EFF;
- for (i = start_symbol; i < nsyms; i++)
- {
- sp = derives[i];
- for (rule = *sp; rule > 0; rule = *++sp)
- {
- symbol = ritem[rrhs[rule]];
- if (ISVAR(symbol))
- {
- symbol -= start_symbol;
- SETBIT(row, symbol);
- }
- }
- row += rowsize;
- }
- reflexive_transitive_closure(EFF, nvars);
- #ifdef DEBUG
- print_EFF();
- #endif
- }
- void
- set_first_derives(void)
- {
- unsigned *rrow;
- unsigned *vrow;
- int j;
- unsigned k;
- unsigned cword = 0;
- short *rp;
- int rule;
- int i;
- int rulesetsize;
- int varsetsize;
- rulesetsize = WORDSIZE(nrules);
- varsetsize = WORDSIZE(nvars);
- first_derives = NEW2(nvars * rulesetsize, unsigned) - ntokens * rulesetsize;
- set_EFF();
- rrow = first_derives + ntokens * rulesetsize;
- for (i = start_symbol; i < nsyms; i++)
- {
- vrow = EFF + ((i - ntokens) * varsetsize);
- k = BITS_PER_WORD;
- for (j = start_symbol; j < nsyms; k++, j++)
- {
- if (k >= BITS_PER_WORD)
- {
- cword = *vrow++;
- k = 0;
- }
- if (cword & (unsigned)(1 << k))
- {
- rp = derives[j];
- while ((rule = *rp++) >= 0)
- {
- SETBIT(rrow, rule);
- }
- }
- }
- rrow += rulesetsize;
- }
- #ifdef DEBUG
- print_first_derives();
- #endif
- FREE(EFF);
- }
- void
- closure(short *nucleus, int n)
- {
- unsigned ruleno;
- unsigned word;
- unsigned i;
- Value_t *csp;
- unsigned *dsp;
- unsigned *rsp;
- int rulesetsize;
- Value_t *csend;
- unsigned *rsend;
- int symbol;
- Value_t itemno;
- rulesetsize = WORDSIZE(nrules);
- rsend = ruleset + rulesetsize;
- for (rsp = ruleset; rsp < rsend; rsp++)
- *rsp = 0;
- csend = nucleus + n;
- for (csp = nucleus; csp < csend; ++csp)
- {
- symbol = ritem[*csp];
- if (ISVAR(symbol))
- {
- dsp = first_derives + symbol * rulesetsize;
- rsp = ruleset;
- while (rsp < rsend)
- *rsp++ |= *dsp++;
- }
- }
- ruleno = 0;
- itemsetend = itemset;
- csp = nucleus;
- for (rsp = ruleset; rsp < rsend; ++rsp)
- {
- word = *rsp;
- if (word)
- {
- for (i = 0; i < BITS_PER_WORD; ++i)
- {
- if (word & (unsigned)(1 << i))
- {
- itemno = rrhs[ruleno + i];
- while (csp < csend && *csp < itemno)
- *itemsetend++ = *csp++;
- *itemsetend++ = itemno;
- while (csp < csend && *csp == itemno)
- ++csp;
- }
- }
- }
- ruleno += BITS_PER_WORD;
- }
- while (csp < csend)
- *itemsetend++ = *csp++;
- #ifdef DEBUG
- print_closure(n);
- #endif
- }
- void
- finalize_closure(void)
- {
- FREE(itemset);
- FREE(ruleset);
- FREE(first_derives + ntokens * WORDSIZE(nrules));
- }
- #ifdef DEBUG
- void
- print_closure(int n)
- {
- short *isp;
- printf("\n\nn = %d\n\n", n);
- for (isp = itemset; isp < itemsetend; isp++)
- printf(" %d\n", *isp);
- }
- void
- print_EFF(void)
- {
- int i, j;
- unsigned *rowp;
- unsigned word;
- unsigned k;
- printf("\n\nEpsilon Free Firsts\n");
- for (i = start_symbol; i < nsyms; i++)
- {
- printf("\n%s", symbol_name[i]);
- rowp = EFF + ((i - start_symbol) * WORDSIZE(nvars));
- word = *rowp++;
- k = BITS_PER_WORD;
- for (j = 0; j < nvars; k++, j++)
- {
- if (k >= BITS_PER_WORD)
- {
- word = *rowp++;
- k = 0;
- }
- if (word & (1 << k))
- printf(" %s", symbol_name[start_symbol + j]);
- }
- }
- }
- void
- print_first_derives(void)
- {
- int i;
- int j;
- unsigned *rp;
- unsigned cword = 0;
- unsigned k;
- printf("\n\n\nFirst Derives\n");
- for (i = start_symbol; i < nsyms; i++)
- {
- printf("\n%s derives\n", symbol_name[i]);
- rp = first_derives + i * WORDSIZE(nrules);
- k = BITS_PER_WORD;
- for (j = 0; j <= nrules; k++, j++)
- {
- if (k >= BITS_PER_WORD)
- {
- cword = *rp++;
- k = 0;
- }
- if (cword & (1 << k))
- printf(" %d\n", j);
- }
- }
- fflush(stdout);
- }
- #endif