126 lines
		
	
	
		
			3.0 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			126 lines
		
	
	
		
			3.0 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*	$NetBSD: warshall.c,v 1.8 2006/05/24 18:01:43 christos Exp $	*/
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/*
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 * Copyright (c) 1989 The Regents of the University of California.
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 * All rights reserved.
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 *
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 * This code is derived from software contributed to Berkeley by
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 * Robert Paul Corbett.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 * 1. Redistributions of source code must retain the above copyright
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 *    notice, this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    notice, this list of conditions and the following disclaimer in the
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 *    documentation and/or other materials provided with the distribution.
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 * 3. Neither the name of the University nor the names of its contributors
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 *    may be used to endorse or promote products derived from this software
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 *    without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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 * SUCH DAMAGE.
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 */
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#include <sys/cdefs.h>
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#if defined(__RCSID) && !defined(lint)
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#if 0
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static char sccsid[] = "@(#)warshall.c	5.4 (Berkeley) 5/24/93";
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#else
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__RCSID("$NetBSD: warshall.c,v 1.8 2006/05/24 18:01:43 christos Exp $");
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#endif
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#endif /* not lint */
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#include "defs.h"
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static void transitive_closure(unsigned *, int);
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static void
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transitive_closure(unsigned *R, int n)
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{
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    int rowsize;
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    unsigned i;
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    unsigned *rowj;
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    unsigned *rp;
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    unsigned *rend;
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    unsigned *ccol;
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    unsigned *relend;
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    unsigned *cword;
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    unsigned *rowi;
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    rowsize = WORDSIZE(n);
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    relend = R + n*rowsize;
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    cword = R;
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    i = 0;
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    rowi = R;
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    while (rowi < relend)
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    {
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	ccol = cword;
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	rowj = R;
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	while (rowj < relend)
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	{
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	    if (*ccol & (1 << i))
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	    {
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		rp = rowi;
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		rend = rowj + rowsize;
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		while (rowj < rend)
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		    *rowj++ |= *rp++;
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	    }
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	    else
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	    {
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		rowj += rowsize;
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	    }
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	    ccol += rowsize;
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	}
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	if (++i >= BITS_PER_WORD)
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	{
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	    i = 0;
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	    cword++;
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	}
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	rowi += rowsize;
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    }
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}
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void
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reflexive_transitive_closure(unsigned *R, int n)
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{
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    int rowsize;
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    unsigned i;
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    unsigned *rp;
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    unsigned *relend;
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    transitive_closure(R, n);
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    rowsize = WORDSIZE(n);
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    relend = R + n*rowsize;
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    i = 0;
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    rp = R;
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    while (rp < relend)
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    {
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	*rp |= (1 << i);
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	if (++i >= BITS_PER_WORD)
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	{
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	    i = 0;
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	    rp++;
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	}
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	rp += rowsize;
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    }
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}
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