minix/commands/yacc/warshall.c
2010-05-12 16:28:54 +00:00

125 lines
3 KiB
C

/* $NetBSD: warshall.c,v 1.8 2006/05/24 18:01:43 christos 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 <sys/cdefs.h>
#if defined(__RCSID) && !defined(lint)
#if 0
static char sccsid[] = "@(#)warshall.c 5.4 (Berkeley) 5/24/93";
#else
__RCSID("$NetBSD: warshall.c,v 1.8 2006/05/24 18:01:43 christos Exp $");
#endif
#endif /* not lint */
#include "defs.h"
static void transitive_closure(unsigned *, int);
static void
transitive_closure(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(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;
}
}