bin/yacc/warshall.c

   1 /* $OpenBSD: warshall.c,v 1.11 2014/03/13 01:18:22 tedu 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. Neither the name of the University nor the names of its contributors
  20  *    may be used to endorse or promote products derived from this software
  21  *    without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  */
  35
  36 #include "defs.h"
  37
  38 void transitive_closure(unsigned int *, int);
  39
  40 void
  41 transitive_closure(unsigned int *R, int n)
  42 {
  43         int rowsize;
  44         unsigned int i;
  45         unsigned int *rowj, *rp, *rend, *ccol, *relend, *cword, *rowi;
  46
  47         rowsize = WORDSIZE(n);
  48         relend = R + n * rowsize;
  49
  50         cword = R;
  51         i = 0;
  52         rowi = R;
  53         while (rowi < relend) {
  54                 ccol = cword;
  55                 rowj = R;
  56
  57                 while (rowj < relend) {
  58                         if (*ccol & (1 << i)) {
  59                                 rp = rowi;
  60                                 rend = rowj + rowsize;
  61                                 while (rowj < rend)
  62                                         *rowj++ |= *rp++;
  63                         } else {
  64                                 rowj += rowsize;
  65                         }
  66
  67                         ccol += rowsize;
  68                 }
  69
  70                 if (++i >= BITS_PER_WORD) {
  71                         i = 0;
  72                         cword++;
  73                 }
  74                 rowi += rowsize;
  75         }
  76 }
  77
  78 void
  79 reflexive_transitive_closure(unsigned int *R, int n)
  80 {
  81         int rowsize;
  82         unsigned int i;
  83         unsigned int *rp, *relend;
  84
  85         transitive_closure(R, n);
  86
  87         rowsize = WORDSIZE(n);
  88         relend = R + n * rowsize;
  89
  90         i = 0;
  91         rp = R;
  92         while (rp < relend) {
  93                 *rp |= (1 << i);
  94                 if (++i >= BITS_PER_WORD) {
  95                         i = 0;
  96                         rp++;
  97                 }
  98                 rp += rowsize;
  99         }
 100 }