source: vendor/FreeBSD-yacc/current/warshall.c

/*
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 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[] = "@(#)warshall.c  5.4 (Berkeley) 5/24/93";
#endif
#endif

#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/usr.bin/yacc/warshall.c,v 1.12 2002/04/09 11:39:05 ru Exp $");

#include "defs.h"

static void transitive_closure(unsigned *, int);

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