warshall.c revision 1.4
1/* $OpenBSD: warshall.c,v 1.4 2001/07/16 06:29:45 pvalchev 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 1.4 2001/07/16 06:29:45 pvalchev Exp $"; 45#endif 46#endif /* not lint */ 47 48#include "defs.h" 49 50void transitive_closure __P((unsigned *, int)); 51 52void 53transitive_closure(R, n) 54unsigned *R; 55int n; 56{ 57 register int rowsize; 58 register unsigned i; 59 register unsigned *rowj; 60 register unsigned *rp; 61 register unsigned *rend; 62 register unsigned *ccol; 63 register unsigned *relend; 64 register unsigned *cword; 65 register unsigned *rowi; 66 67 rowsize = WORDSIZE(n); 68 relend = R + n*rowsize; 69 70 cword = R; 71 i = 0; 72 rowi = R; 73 while (rowi < relend) 74 { 75 ccol = cword; 76 rowj = R; 77 78 while (rowj < relend) 79 { 80 if (*ccol & (1 << i)) 81 { 82 rp = rowi; 83 rend = rowj + rowsize; 84 while (rowj < rend) 85 *rowj++ |= *rp++; 86 } 87 else 88 { 89 rowj += rowsize; 90 } 91 92 ccol += rowsize; 93 } 94 95 if (++i >= BITS_PER_WORD) 96 { 97 i = 0; 98 cword++; 99 } 100 101 rowi += rowsize; 102 } 103} 104 105void 106reflexive_transitive_closure(R, n) 107unsigned *R; 108int n; 109{ 110 register int rowsize; 111 register unsigned i; 112 register unsigned *rp; 113 register unsigned *relend; 114 115 transitive_closure(R, n); 116 117 rowsize = WORDSIZE(n); 118 relend = R + n*rowsize; 119 120 i = 0; 121 rp = R; 122 while (rp < relend) 123 { 124 *rp |= (1 << i); 125 if (++i >= BITS_PER_WORD) 126 { 127 i = 0; 128 rp++; 129 } 130 131 rp += rowsize; 132 } 133} 134