/usr.bin/yacc/closure.c
https://bitbucket.org/freebsd/freebsd-head/ · C · 306 lines · 225 code · 50 blank · 31 comment · 31 complexity · d5fccf46206dfab6fb98b39435f47941 MD5 · raw file
- /*
- * Copyright (c) 1989 The Regents of the University of California.
- * All rights reserved.
- *
- * This code is derived from software contributed to Berkeley by
- * Robert Paul Corbett.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- * 4. Neither the name of the University nor the names of its contributors
- * may be used to endorse or promote products derived from this software
- * without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
- #if 0
- #ifndef lint
- static char sccsid[] = "@(#)closure.c 5.3 (Berkeley) 5/24/93";
- #endif
- #endif
- #include <sys/cdefs.h>
- __FBSDID("$FreeBSD$");
- #include <stdlib.h>
- #include "defs.h"
- short *itemset;
- short *itemsetend;
- unsigned *ruleset;
- static void set_EFF(void);
- #ifdef DEBUG
- static void print_closure(int);
- static void print_EFF();
- static void print_first_derives();
- #endif
- 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 & (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)
- {
- int ruleno;
- unsigned word;
- unsigned i;
- short *csp;
- unsigned *dsp;
- unsigned *rsp;
- int rulesetsize;
- short *csend;
- unsigned *rsend;
- int symbol;
- int 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 & (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
- static void
- print_closure(int n)
- {
- short *isp;
- printf("\n\nn = %d\n\n", n);
- for (isp = itemset; isp < itemsetend; isp++)
- printf(" %d\n", *isp);
- }
- static 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]);
- }
- }
- }
- static void
- print_first_derives(void)
- {
- int i;
- int j;
- unsigned *rp;
- unsigned cword;
- 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