warshall.c revision 1.3 
1/*	$OpenBSD: warshall.c,v 1.3 1996/06/26 05:44:40 deraadt Exp $	*/
2/*	$NetBSD: warshall.c,v 1.4 1996/03/19 03:21:51 jtc Exp $	*/
3
4/*
5 * Copyright (c) 1989 The Regents of the University of California.
6 * All rights reserved.
7 *
8 * This code is derived from software contributed to Berkeley by
9 * Robert Paul Corbett.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 *    notice, this list of conditions and the following disclaimer in the
18 *    documentation and/or other materials provided with the distribution.
19 * 3. All advertising materials mentioning features or use of this software
20 *    must display the following acknowledgement:
21 *	This product includes software developed by the University of
22 *	California, Berkeley and its contributors.
23 * 4. Neither the name of the University nor the names of its contributors
24 *    may be used to endorse or promote products derived from this software
25 *    without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * SUCH DAMAGE.
38 */
39
40#ifndef lint
41#if 0
42static char sccsid[] = "@(#)warshall.c	5.4 (Berkeley) 5/24/93";
43#else
44static char rcsid[] = "$OpenBSD: warshall.c,v 1.3 1996/06/26 05:44:40 deraadt Exp $";
45#endif
46#endif /* not lint */
47
48#include "defs.h"
49
50transitive_closure(R, n)
51unsigned *R;
52int n;
53{
54    register int rowsize;
55    register unsigned i;
56    register unsigned *rowj;
57    register unsigned *rp;
58    register unsigned *rend;
59    register unsigned *ccol;
60    register unsigned *relend;
61    register unsigned *cword;
62    register unsigned *rowi;
63
64    rowsize = WORDSIZE(n);
65    relend = R + n*rowsize;
66
67    cword = R;
68    i = 0;
69    rowi = R;
70    while (rowi < relend)
71    {
72	ccol = cword;
73	rowj = R;
74
75	while (rowj < relend)
76	{
77	    if (*ccol & (1 << i))
78	    {
79		rp = rowi;
80		rend = rowj + rowsize;
81		while (rowj < rend)
82		    *rowj++ |= *rp++;
83	    }
84	    else
85	    {
86		rowj += rowsize;
87	    }
88
89	    ccol += rowsize;
90	}
91
92	if (++i >= BITS_PER_WORD)
93	{
94	    i = 0;
95	    cword++;
96	}
97
98	rowi += rowsize;
99    }
100}
101
102reflexive_transitive_closure(R, n)
103unsigned *R;
104int n;
105{
106    register int rowsize;
107    register unsigned i;
108    register unsigned *rp;
109    register unsigned *relend;
110
111    transitive_closure(R, n);
112
113    rowsize = WORDSIZE(n);
114    relend = R + n*rowsize;
115
116    i = 0;
117    rp = R;
118    while (rp < relend)
119    {
120	*rp |= (1 << i);
121	if (++i >= BITS_PER_WORD)
122	{
123	    i = 0;
124	    rp++;
125	}
126
127	rp += rowsize;
128    }
129}
130