87 lines
1.3 KiB
C
87 lines
1.3 KiB
C
/* $NetBSD: warshall.c,v 1.6 2011/09/10 21:29:04 christos Exp $ */
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/* Id: warshall.c,v 1.7 2010/06/06 22:48:51 tom Exp */
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#include "defs.h"
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#include <sys/cdefs.h>
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__RCSID("$NetBSD: warshall.c,v 1.6 2011/09/10 21:29:04 christos Exp $");
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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 & (unsigned)(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 |= (unsigned)(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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