1/* $OpenBSD: warshall.c,v 1.11 2014/03/13 01:18:22 tedu 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. Neither the name of the University nor the names of its contributors
20 *    may be used to endorse or promote products derived from this software
21 *    without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36#include "defs.h"
37
38void transitive_closure(unsigned int *, int);
39
40void
41transitive_closure(unsigned int *R, int n)
42{
43	int rowsize;
44	unsigned int i;
45	unsigned int *rowj, *rp, *rend, *ccol, *relend, *cword, *rowi;
46
47	rowsize = WORDSIZE(n);
48	relend = R + n * rowsize;
49
50	cword = R;
51	i = 0;
52	rowi = R;
53	while (rowi < relend) {
54		ccol = cword;
55		rowj = R;
56
57		while (rowj < relend) {
58			if (*ccol & (1 << i)) {
59				rp = rowi;
60				rend = rowj + rowsize;
61				while (rowj < rend)
62					*rowj++ |= *rp++;
63			} else {
64				rowj += rowsize;
65			}
66
67			ccol += rowsize;
68		}
69
70		if (++i >= BITS_PER_WORD) {
71			i = 0;
72			cword++;
73		}
74		rowi += rowsize;
75	}
76}
77
78void
79reflexive_transitive_closure(unsigned int *R, int n)
80{
81	int rowsize;
82	unsigned int i;
83	unsigned int *rp, *relend;
84
85	transitive_closure(R, n);
86
87	rowsize = WORDSIZE(n);
88	relend = R + n * rowsize;
89
90	i = 0;
91	rp = R;
92	while (rp < relend) {
93		*rp |= (1 << i);
94		if (++i >= BITS_PER_WORD) {
95			i = 0;
96			rp++;
97		}
98		rp += rowsize;
99	}
100}
101