scyther/src/warshall.c

// @file warshall.c
/* Based on public-domain code from Berkeley Yacc */

#include "warshall.h"

void
transitive_closure (unsigned int *R, int n)
{
  register int rowsize;
  register unsigned mask;
  register unsigned *rowj;
  register unsigned *rp;
  register unsigned *rend;
  register unsigned *ccol;
  register unsigned *relend;
  register unsigned *cword;
  register unsigned *rowi;

  rowsize = WORDSIZE (n);
  relend = R + n * rowsize;

  cword = R;
  mask = 1;
  rowi = R;
  while (rowi < relend)
    {
      ccol = cword;
      rowj = R;

      while (rowj < relend)
	{
	  if (*ccol & mask)
	    {
	      rp = rowi;
	      rend = rowj + rowsize;
	      while (rowj < rend)
		*rowj++ |= *rp++;
	    }
	  else
	    {
	      rowj += rowsize;
	    }

	  ccol += rowsize;
	}

      mask <<= 1;
      if (mask == 0)
	{
	  mask = 1;
	  cword++;
	}

      rowi += rowsize;
    }
}

void
reflexive_transitive_closure (unsigned int *R, int n)
{
  register int rowsize;
  register unsigned mask;
  register unsigned *rp;
  register unsigned *relend;

  transitive_closure (R, n);

  rowsize = WORDSIZE (n);
  relend = R + n * rowsize;

  mask = 1;
  rp = R;
  while (rp < relend)
    {
      *rp |= mask;
      mask <<= 1;
      if (mask == 0)
	{
	  mask = 1;
	  rp++;
	}

      rp += rowsize;
    }
}