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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| /*
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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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| 
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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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| 
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| #include "defs.h"
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| 
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| static void transitive_closure(unsigned *, int);
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| 
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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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| 
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|     rowsize = WORDSIZE(n);
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|     relend = R + n*rowsize;
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| 
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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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| 
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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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| 
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| 	    ccol += rowsize;
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| 	}
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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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| 
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| 	rowi += rowsize;
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|     }
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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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| 
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|     transitive_closure(R, n);
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| 
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|     rowsize = WORDSIZE(n);
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|     relend = R + n*rowsize;
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| 
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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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| 
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| 	rp += rowsize;
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|     }
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| }
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