mcs/jay/warshall.c

   1 /*
   2  * Copyright (c) 1989 The Regents of the University of California.
   3  * All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Robert Paul Corbett.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  */
  36
  37 #ifndef lint
  38 static char sccsid[] = "@(#)warshall.c  5.4 (Berkeley) 5/24/93";
  39 #endif /* not lint */
  40
  41 #include "defs.h"
  42
  43 static void
  44 transitive_closure (unsigned *R, int n)
  45 {
  46     register int rowsize;
  47     register unsigned i;
  48     register unsigned *rowj;
  49     register unsigned *rp;
  50     register unsigned *rend;
  51     register unsigned *ccol;
  52     register unsigned *relend;
  53     register unsigned *cword;
  54     register unsigned *rowi;
  55
  56     rowsize = WORDSIZE(n);
  57     relend = R + n*rowsize;
  58
  59     cword = R;
  60     i = 0;
  61     rowi = R;
  62     while (rowi < relend)
  63     {
  64         ccol = cword;
  65         rowj = R;
  66
  67         while (rowj < relend)
  68         {
  69             if (*ccol & (1 << i))
  70             {
  71                 rp = rowi;
  72                 rend = rowj + rowsize;
  73                 while (rowj < rend)
  74                     *rowj++ |= *rp++;
  75             }
  76             else
  77             {
  78                 rowj += rowsize;
  79             }
  80
  81             ccol += rowsize;
  82         }
  83
  84         if (++i >= BITS_PER_WORD)
  85         {
  86             i = 0;
  87             cword++;
  88         }
  89
  90         rowi += rowsize;
  91     }
  92 }
  93
  94 void
  95 reflexive_transitive_closure (unsigned *R, int n)
  96 {
  97     register int rowsize;
  98     register unsigned i;
  99     register unsigned *rp;
 100     register unsigned *relend;
 101
 102     transitive_closure(R, n);
 103
 104     rowsize = WORDSIZE(n);
 105     relend = R + n*rowsize;
 106
 107     i = 0;
 108     rp = R;
 109     while (rp < relend)
 110     {
 111         *rp |= (1 << i);
 112         if (++i >= BITS_PER_WORD)
 113         {
 114             i = 0;
 115             rp++;
 116         }
 117
 118         rp += rowsize;
 119     }
 120 }