src/warshall.c

/* Generate transitive closure of a matrix,
   Copyright 1984, 1989, 2000 Free Software Foundation, Inc.

   This file is part of Bison, the GNU Compiler Compiler.

   Bison is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   Bison is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with Bison; see the file COPYING.  If not, write to
   the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */


#include "system.h"
#include "warshall.h"

/* Given n by n matrix of bits R, modify its contents to be the
   transive closure of what was given.  */

static void
TC (unsigned *R, int n)
{
  int rowsize;
  unsigned mask;
  unsigned *rowj;
  unsigned *rp;
  unsigned *rend;
  unsigned *ccol;

  unsigned *relend;
  unsigned *cword;
  unsigned *rowi;

  rowsize = WORDSIZE(n) * sizeof(unsigned);
  relend = (unsigned *) ((char *) 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 = (unsigned *) ((char *) rowj + rowsize);

	      while (rowj < rend)
		*rowj++ |= *rp++;
	    }
	  else
	    {
	      rowj = (unsigned *) ((char *) rowj + rowsize);
	    }

	  ccol = (unsigned *) ((char *) ccol + rowsize);
	}

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

      rowi = (unsigned *) ((char *) rowi + rowsize);
    }
}


/* Reflexive Transitive Closure.  Same as TC
   and then set all the bits on the diagonal of R.  */

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

  TC(R, n);

  rowsize = WORDSIZE(n) * sizeof(unsigned);
  relend = (unsigned *) ((char *) R + n*rowsize);

  mask = 1;
  rp = R;
  while (rp < relend)
    {
      *rp |= mask;

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

      rp = (unsigned *) ((char *) rp + rowsize);
    }
}
Commit	Line	Data
	1	/* Generate transitive closure of a matrix,
	2	Copyright 1984, 1989, 2000 Free Software Foundation, Inc.
	3
	4	This file is part of Bison, the GNU Compiler Compiler.
	5
	6	Bison is free software; you can redistribute it and/or modify
	7	it under the terms of the GNU General Public License as published by
	8	the Free Software Foundation; either version 2, or (at your option)
	9	any later version.
	10
	11	Bison is distributed in the hope that it will be useful,
	12	but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	GNU General Public License for more details.
	15
	16	You should have received a copy of the GNU General Public License
	17	along with Bison; see the file COPYING. If not, write to
	18	the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
	19	Boston, MA 02111-1307, USA. */
	20
	21
	22	#include "system.h"
	23	#include "warshall.h"
	24
	25	/* Given n by n matrix of bits R, modify its contents to be the
	26	transive closure of what was given. */
	27
	28	static void
	29	TC (unsigned *R, int n)
	30	{
	31	int rowsize;
	32	unsigned mask;
	33	unsigned *rowj;
	34	unsigned *rp;
	35	unsigned *rend;
	36	unsigned *ccol;
	37
	38	unsigned *relend;
	39	unsigned *cword;
	40	unsigned *rowi;
	41
	42	rowsize = WORDSIZE(n) * sizeof(unsigned);
	43	relend = (unsigned ) ((char ) R + (n * rowsize));
	44
	45	cword = R;
	46	mask = 1;
	47	rowi = R;
	48	while (rowi < relend)
	49	{
	50	ccol = cword;
	51	rowj = R;
	52
	53	while (rowj < relend)
	54	{
	55	if (*ccol & mask)
	56	{
	57	rp = rowi;
	58	rend = (unsigned ) ((char ) rowj + rowsize);
	59
	60	while (rowj < rend)
	61	rowj++ \|= rp++;
	62	}
	63	else
	64	{
	65	rowj = (unsigned ) ((char ) rowj + rowsize);
	66	}
	67
	68	ccol = (unsigned ) ((char ) ccol + rowsize);
	69	}
	70
	71	mask <<= 1;
	72	if (mask == 0)
	73	{
	74	mask = 1;
	75	cword++;
	76	}
	77
	78	rowi = (unsigned ) ((char ) rowi + rowsize);
	79	}
	80	}
	81
	82
	83	/* Reflexive Transitive Closure. Same as TC
	84	and then set all the bits on the diagonal of R. */
	85
	86	void
	87	RTC (unsigned *R, int n)
	88	{
	89	int rowsize;
	90	unsigned mask;
	91	unsigned *rp;
	92	unsigned *relend;
	93
	94	TC(R, n);
	95
	96	rowsize = WORDSIZE(n) * sizeof(unsigned);
	97	relend = (unsigned ) ((char ) R + n*rowsize);
	98
	99	mask = 1;
	100	rp = R;
	101	while (rp < relend)
	102	{
	103	*rp \|= mask;
	104
	105	mask <<= 1;
	106	if (mask == 0)
	107	{
	108	mask = 1;
	109	rp++;
	110	}
	111
	112	rp = (unsigned ) ((char ) rp + rowsize);
	113	}
	114	}