xref: /openbsd-src/usr.bin/yacc/warshall.c (revision 8d3728c6f703dfa010fc9e102c7d13f5b94bc31f)

/* $OpenBSD: warshall.c,v 1.11 2014/03/13 01:18:22 tedu Exp $	 */
/* $NetBSD: warshall.c,v 1.4 1996/03/19 03:21:51 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"

void transitive_closure(unsigned int *, int);

void
transitive_closure(unsigned int *R, int n)
{
	int rowsize;
	unsigned int i;
	unsigned int *rowj, *rp, *rend, *ccol, *relend, *cword, *rowi;

	rowsize = WORDSIZE(n);
	relend = R + n * rowsize;

	cword = R;
	i = 0;
	rowi = R;
	while (rowi < relend) {
		ccol = cword;
		rowj = R;

		while (rowj < relend) {
			if (*ccol & (1 << i)) {
				rp = rowi;
				rend = rowj + rowsize;
				while (rowj < rend)
					*rowj++ |= *rp++;
			} else {
				rowj += rowsize;
			}

			ccol += rowsize;
		}

		if (++i >= BITS_PER_WORD) {
			i = 0;
			cword++;
		}
		rowi += rowsize;
	}
}

void
reflexive_transitive_closure(unsigned int *R, int n)
{
	int rowsize;
	unsigned int i;
	unsigned int *rp, *relend;

	transitive_closure(R, n);

	rowsize = WORDSIZE(n);
	relend = R + n * rowsize;

	i = 0;
	rp = R;
	while (rp < relend) {
		*rp |= (1 << i);
		if (++i >= BITS_PER_WORD) {
			i = 0;
			rp++;
		}
		rp += rowsize;
	}
}