fatbase

closure.c (5486B)

---

 /*	$OpenBSD: closure.c,v 1.13 2014/03/13 01:18:22 tedu Exp $	*/
 /*	$NetBSD: closure.c,v 1.4 1996/03/19 03:21:29 jtc Exp $	*/
 
 /*
  * 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.
  * 3. 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.
  */
 
 #include "defs.h"
 
 short *itemset;
 short *itemsetend;
 unsigned *ruleset;
 
 static unsigned *first_derives;
 static unsigned *EFF;
 
 
 void
 set_EFF(void)
 {
 	unsigned int *row;
 	int symbol, rowsize, i, rule;
 	short *sp;
 
 	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 int *rrow, *vrow;
 	unsigned int k, cword = 0;
 	int i, j, rule, rulesetsize, varsetsize;
 	short *rp;
 
 	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);
 				}
 			}
 		}
 
 		vrow += varsetsize;
 		rrow += rulesetsize;
 	}
 
 #ifdef	DEBUG
 	print_first_derives();
 #endif
 
 	free(EFF);
 }
 
 
 void
 closure(short *nucleus, int n)
 {
 	unsigned int i, word;
 	short *csp, *csend;
 	unsigned int *dsp, *rsp, *rsend;
 	int rulesetsize;
 	int ruleno, symbol, itemno;
 
 	rulesetsize = WORDSIZE(nrules);
 	rsend = ruleset + rulesetsize;
 	memset(ruleset, 0, rulesetsize * sizeof(*ruleset));
 
 	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
 
 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 int *rowp;
 	unsigned int k, word;
 
 	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, j;
 	unsigned int *rp;
 	unsigned int k, cword = 0;
 
 	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