bison/lib/bitset.c

/* General bitsets.
   Copyright (C) 2002 Free Software Foundation, Inc.
   Contributed by Michael Hayes (m.hayes@elec.canterbury.ac.nz).

This program 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 of the License, or
(at your option) any later version.

This program 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 this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <stdlib.h>
#include "bitset.h"
#include "obstack.h"

static void bitset_print PARAMS ((FILE *, bitset, int));

#if BITSET_CHECK
#define BITSET__CHECK2(DST, SRC) \
if ((DST)->OPS != (SRC)->OPS) abort ();

#define BITSET__CHECK3(DST, SRC1, SRC2) \
if ((DST)->OPS != (SRC1)->OPS || (DST)->OPS != (SRC2)->OPS) abort ();

#define BITSET__CHECK4(DST, SRC1, SRC2) \
if ((DST)->OPS != (SRC1)->OPS || (DST)->OPS != (SRC2)->OPS \
    || (DST)->OPS != (SRC3)->OPS) abort ();
#else
#define BITSET__CHECK2(DST, SRC)

#define BITSET__CHECK3(DST, SRC1, SRC2)

#define BITSET__CHECK4(DST, SRC1, SRC2, SRC3)
#endif

#if BITSET_STATS
#define BITSET_STATS_FILE "bitset.dat"

#define BITSET_LOG_COUNT_BINS 10
#define BITSET_LOG_SIZE_BINS  16
#define BITSET_DENSITY_BINS  20

struct bitset_type_stats_struct
{
  unsigned int xmallocs;
  unsigned int xfrees;
  unsigned int oballocs;
  unsigned int obfrees;
  unsigned int lists;
  unsigned int list_counts[BITSET_LOG_COUNT_BINS];
  unsigned int list_sizes[BITSET_LOG_SIZE_BINS];
  unsigned int list_density[BITSET_DENSITY_BINS];
};

struct bitset_stats_struct
{
    unsigned int runs;
    struct bitset_type_stats_struct types[BITSET_TYPE_NUM];
};

struct bitset_stats_struct bitset_stats_data;
struct bitset_stats_struct *bitset_stats;

static void bitset_percent_histogram_print PARAMS ((FILE *, const char *,
						    const char *,
						    unsigned int,
						    unsigned int *));
static void bitset_log_histogram_print PARAMS ((FILE *, const char *,
						const char *,
						unsigned int, unsigned int *));
static void bitset_stats_print_1 PARAMS ((FILE *, const char *,
					  struct bitset_type_stats_struct *));
static void bitset_stats_print PARAMS ((FILE *, int));
static void bitset_stats_read PARAMS ((void));
static void bitset_stats_write PARAMS ((void));

#define BITSET_STATS_XMALLOCS_INC(TYPE) 		\
  if (bitset_stats)					\
    bitset_stats->types[(TYPE)].xmallocs++

#define BITSET_STATS_XFREES_INC(BSET) 			\
  if (bitset_stats)					\
    bitset_stats->types[(BSET)->ops->type].xfrees++

#define BITSET_STATS_OBALLOCS_INC(TYPE) 		\
  if (bitset_stats)					\
    bitset_stats->types[(TYPE)].oballocs++

#define BITSET_STATS_OBFREES_INC(BSET) 		\
  if (bitset_stats)					\
    bitset_stats->types[(BSET)->ops->type].obfrees++

#define BITSET_STATS_LISTS_INC(BSET) 			\
  if (bitset_stats)					\
    bitset_stats->types[(BSET)->ops->type].lists++

#define BITSET_STATS_LIST_COUNTS_INC(BSET, I) 		\
  if (bitset_stats)					\
    bitset_stats->types[(BSET)->ops->type].list_counts[(I)]++

#define BITSET_STATS_LIST_SIZES_INC(BSET, I) 		\
  if (bitset_stats)					\
    bitset_stats->types[(BSET)->ops->type].list_sizes[(I)]++

#define BITSET_STATS_LIST_DENSITY_INC(BSET, I) 		\
  if (bitset_stats)					\
    bitset_stats->types[(BSET)->ops->type].list_density[(I)]++

#else
#define BITSET_STATS_XMALLOCS_INC(TYPE)

#define BITSET_STATS_XFREES_INC(BSET)

#define BITSET_STATS_OBALLOCS_INC(TYPE)

#define BITSET_STATS_OBFREES_INC(BSET)

#define BITSET_STATS_LISTS_INC(BSET)

#define BITSET_STATS_LIST_COUNTS_INC(BSET, I)

#define BITSET_STATS_LIST_SIZES_INC(BSET, I)

#define BITSET_STATS_LIST_DENSITY_INC(BSET, I)
#endif /* BITSET_STATS  */



/* Return number of bytes required to create a N_BIT bitset
   of TYPE.  The bitset may grow to require more bytes than this.  */
int
bitset_bytes (type, n_bits)
     enum bitset_type type;
     bitset_bindex n_bits;
{
  unsigned int bytes;

  switch (type)
    {
    case BITSET_ARRAY:
      bytes = sbitset_bytes (n_bits);
      break;

    case BITSET_LIST:
      bytes = lbitset_bytes (n_bits);
      break;

    case BITSET_TABLE:
      bytes = ebitset_bytes (n_bits);
      break;

    default:
      abort ();
    }

  return bytes;
}


/* Initialise bitset BSET of TYPE for N_BITS.  */
bitset
bitset_init (bset, n_bits, type)
     bitset bset;
     bitset_bindex n_bits;
     enum bitset_type type;
{
  switch (type)
    {
    case BITSET_ARRAY:
      return sbitset_init (bset, n_bits);

    case BITSET_LIST:
      return lbitset_init (bset, n_bits);

    case BITSET_TABLE:
      return ebitset_init (bset, n_bits);

    default:
      abort ();
    }
}


/* Select a bitset type for a set of N_BITS and with attribute hints
   specified by ATTR.  For variable size bitsets, N_BITS is only a
   hint and may be zero.  */
enum bitset_type
bitset_type_choose (n_bits, attr)
     bitset_bindex n_bits ATTRIBUTE_UNUSED;
     unsigned int attr;
{
  enum bitset_type type;

#ifdef ENABLE_CHECKING
  /* Check attributes.  */
  if (attr & BITSET_FIXED && attr & BITSET_VARIABLE)
    abort ();
  if (attr & BITSET_SPARSE && attr & BITSET_DENSE)
    abort ();

  /* Note that sometimes we will be asked for a zero length
     fixed size bitset.  */
#endif

  /* Choose the type of bitset.  */

  type = BITSET_ARRAY;
  /* Currently, the simple bitsets do not support a variable size.  */
  if (attr & BITSET_VARIABLE || attr & BITSET_SPARSE)
    {
      type = BITSET_LIST;
      if (attr & BITSET_DENSE || attr & BITSET_GREEDY)
	type = BITSET_TABLE;
    }

  return type;
}


/* Create a bitset of N_BITS of type TYPE.  */
bitset
bitset_alloc (n_bits, type)
     bitset_bindex n_bits;
     enum bitset_type type;
{
  unsigned int bytes;
  bitset bset;

  BITSET_STATS_XMALLOCS_INC (type);

  bytes = bitset_bytes (type, n_bits);

  bset = (bitset) xmalloc (bytes);

  return bitset_init (bset, n_bits, type);
}


/* Create a bitset of N_BITS of type TYPE.  */
bitset
bitset_obstack_alloc (bobstack, n_bits, type)
    struct obstack *bobstack;
    bitset_bindex n_bits;
    enum bitset_type type;
{
  unsigned int bytes;

  BITSET_STATS_OBALLOCS_INC (type);

  bytes = bitset_bytes (type, n_bits);

  return bitset_init (obstack_alloc (bobstack, bytes), n_bits, type);
}


/* Create a bitset of N_BITS and with attribute hints specified by
   ATTR.  */
bitset
bitset_create (n_bits, attr)
     bitset_bindex n_bits;
     unsigned int attr;
{
  enum bitset_type type;

  type = bitset_type_choose (n_bits, attr);

  return bitset_alloc (n_bits, type);
}


/* Free bitset BSET.  */
void
bitset_free (bset)
     bitset bset;
{
  BITSET_STATS_XFREES_INC (bset);

  if (bset->ops->free)
    BITSET__FREE (bset);

  bset->ops = NULL;
  free (bset);
}


/* Free bitset BSET allocated on obstack.  */
void
bitset_obstack_free (bset)
     bitset bset;
{
  BITSET_STATS_OBFREES_INC (bset);

  if (bset->ops->free)
    BITSET__FREE (bset);
  bset->ops = NULL;
}


/* Find next bit set in SRC starting from and including BITNO.
   Return -1 if SRC empty.  */
int
bitset_next (src, bitno)
     bitset src;
     bitset_bindex bitno;
{
  bitset_bindex val;
  bitset_bindex next = bitno;

  if (!bitset_list (src, &val, 1, &next))
    return -1;
  return val;
}


/* Find previous bit set in SRC starting from and including BITNO.
   Return -1 if SRC empty.  */
int
bitset_prev (src, bitno)
     bitset src;
     bitset_bindex bitno;
{
  bitset_bindex val;
  bitset_bindex next = bitno;

  if (!bitset_reverse_list (src, &val, 1, &next))
    return -1;
  return val;
}


/* Find first set bit.   */
int
bitset_first (src)
     bitset src;
{
  return bitset_next (src, 0);
}


/* Find last set bit.   */
int
bitset_last (src)
     bitset src;
{
  return bitset_prev (src, 0);
}


static void
bitset_print (file, bset, verbose)
     FILE *file;
     bitset bset;
     int verbose;
{
  unsigned int i, pos;

  if (verbose)
    fprintf (file, "n_bits = %d, set = {", bitset_size (bset));

  pos = 30;
  BITSET_EXECUTE (bset, 0, i,
  {
    if (pos > 70)
      {
	fprintf (file, "\n");
	pos = 0;
      }

    fprintf (file, "%d ", i);
    pos += 1 + (i >= 10) + (i >= 100);
  });

  if (verbose)
    fprintf (file, "}\n");
}


int
bitset_copy (dst, src)
    bitset dst;
    bitset src;
{
    unsigned int i;

    if (dst->ops == src->ops)
	return BITSET__COPY (dst, src);

    /* Convert bitset types.  We assume that the DST bitset
       is large enough to hold the SRC bitset.  */
    bitset_zero (dst);
    BITSET_EXECUTE (src, 0, i,
     {
       bitset_set (dst, i);
     });

    return 1;
}


/* Return size in bits of bitset SRC.  */
int
bitset_size (src)
    bitset src;
{
    return BITSET__SIZE (src);
}


/* DST = 0.  */
int
bitset_zero (dst)
    bitset dst;
{
    return BITSET__OP1 (dst, BITSET_ZERO);
}


/* DST = ~0.  */
int
bitset_ones (dst)
    bitset dst;
{
    return BITSET__OP1 (dst, BITSET_ONES);
}


/* Return non-zero if all bits in bitset SRC are reset.  */
int
bitset_empty_p (src)
    bitset src;
{
    return BITSET__OP1 (src, BITSET_EMPTY_P);
}


/* Return DST == DST | SRC.  */
int
bitset_subset_p (dst, src)
    bitset dst;
    bitset src;
{
    return BITSET__OP2 (dst, src, BITSET_SUBSET_P);
}


/* Return DST == SRC.  */
int
bitset_equal_p (dst, src)
    bitset dst;
    bitset src;
{
    BITSET__CHECK2 (dst, src);
    return BITSET__OP2 (dst, src, BITSET_EQUAL_P);
}


/* DST = ~SRC.  */
int
bitset_not (dst, src)
    bitset dst;
    bitset src;
{
    BITSET__CHECK2 (dst, src);
    return BITSET__OP2 (dst, src, BITSET_NOT);
}


/* DST = SRC1 | SRC2.  Return non-zero if DST != SRC1 | SRC2.  */
int
bitset_or (dst, src1, src2)
    bitset dst;
    bitset src1;
    bitset src2;
{
    BITSET__CHECK3 (dst, src1, src2);
    return BITSET__OP3 (dst, src1, src2, BITSET_OR);
}


/* DST = SRC1 & SRC2.  Return non-zero if DST != SRC1 & SRC2.  */
int
bitset_and (dst, src1, src2)
    bitset dst;
    bitset src1;
    bitset src2;
{
    BITSET__CHECK3 (dst, src1, src2);
    return BITSET__OP3 (dst, src1, src2, BITSET_AND);
}


/* DST = SRC1 ^ SRC2.  Return non-zero if DST != SRC1 ^ SRC2.  */
int
bitset_xor (dst, src1, src2)
    bitset dst;
    bitset src1;
    bitset src2;
{
    BITSET__CHECK3 (dst, src1, src2);
    return BITSET__OP3 (dst, src1, src2, BITSET_XOR);
}


/* DST = SRC1 & ~SRC2.  Return non-zero if DST != SRC1 & ~SRC2.  */
int
bitset_andn (dst, src1, src2)
    bitset dst;
    bitset src1;
    bitset src2;
{
    BITSET__CHECK3 (dst, src1, src2);
    return BITSET__OP3 (dst, src1, src2, BITSET_ANDN);
}


/* DST = SRC1 | ~SRC2.  Return non-zero if DST != SRC1 | ~SRC2.  */
int
bitset_orn (dst, src1, src2)
    bitset dst;
    bitset src1;
    bitset src2;
{
    BITSET__CHECK3 (dst, src1, src2);
    return BITSET__OP3 (dst, src1, src2, BITSET_ORN);
}


/* DST = (SRC1 | SRC2) & SRC3.  Return non-zero if
   DST != (SRC1 | SRC2) & SRC3.  */
int
bitset_or_and (dst, src1, src2, src3)
    bitset dst;
    bitset src1;
    bitset src2;
    bitset src3;
{
    BITSET__CHECK4 (dst, src1, src2, src3);
    return BITSET__OP4 (dst, src1, src2, src3, BITSET_OR_AND);
}


/* DST = (SRC1 & SRC2) | SRC3.  Return non-zero if
   DST != (SRC1 & SRC2) | SRC3.  */
int
bitset_and_or (dst, src1, src2, src3)
    bitset dst;
    bitset src1;
    bitset src2;
    bitset src3;
{
    BITSET__CHECK4 (dst, src1, src2, src3);
    return BITSET__OP4 (dst, src1, src2, src3, BITSET_AND_OR);
}


/* Dump bitset BSET to FILE.  */
void
bitset_dump (file, bset)
     FILE *file;
     bitset bset;
{
  bitset_print (file, bset, 0);
}


/* Function to be called from debugger to print bitset.  */
void
debug_bitset (bset)
     bitset bset;
{
  bitset_print (stderr, bset, 1);
}


/* Release memory associated with bitsets.  */
void
bitset_release_memory ()
{
  lbitset_release_memory ();
  ebitset_release_memory ();
}


#if BITSET_STATS
int
bitset_list (bset, list, num, next)
    bitset bset;
    bitset_bindex *list;
    bitset_bindex num;
    bitset_bindex *next;
{
    bitset_bindex count;

    count = BITSET__LIST (bset, list, num, next);

    if (bitset_stats)
      {
	bitset_bindex tmp;
	bitset_bindex size;
	bitset_bindex i;
	enum bitset_type type;

	type = bset->ops->type;
	BITSET_STATS_LISTS_INC (bset);

	/* Log histogram of number of set bits.  */
	for (i = 0, tmp = count; tmp; tmp >>= 1, i++)
	  continue;
	if (i >= BITSET_LOG_COUNT_BINS)
	  i = BITSET_LOG_COUNT_BINS - 1;
	BITSET_STATS_LIST_COUNTS_INC (bset, i);

	/* Log histogram of number of bits in set.  */
	size = bitset_size (bset);
	for (i = 0, tmp = size; tmp; tmp >>= 1, i++)
	  continue;
	if (i >= BITSET_LOG_SIZE_BINS)
	  i = BITSET_LOG_SIZE_BINS - 1;
	BITSET_STATS_LIST_SIZES_INC (bset, i);

	/* Histogram of fraction of bits set.  */
	i = size ? (count * BITSET_DENSITY_BINS) / size : 0;
	if (i >= BITSET_DENSITY_BINS)
	  i = BITSET_DENSITY_BINS - 1;
	BITSET_STATS_LIST_DENSITY_INC (bset, i);
      }
    return count;
}


/* Print a percentage histogram with message MSG to FILE.  */
static void
bitset_percent_histogram_print (file, name, msg, n_bins, bins)
     FILE *file;
     const char *name;
     const char *msg;
     unsigned int n_bins;
     unsigned int *bins;
{
  unsigned int i;
  unsigned int total;

  total = 0;
  for (i = 0; i < n_bins; i++)
    total += bins[i];

  if (!total)
      return;

  fprintf (file, "%s %s", name, msg);
  for (i = 0; i < n_bins; i++)
    fprintf (file, "%.0f-%.0f%%\t%8d (%5.1f%%)\n",
	     i * 100.0 / n_bins,
	     (i + 1) * 100.0 / n_bins,
	     bins[i], (100.0 * bins[i]) / total);
}


/* Print a log histogram with message MSG to FILE.  */
static void
bitset_log_histogram_print (file, name, msg, n_bins, bins)
     FILE *file;
     const char *name;
     const char *msg;
     unsigned int n_bins;
     unsigned int *bins;
{
  unsigned int i;
  unsigned int total;
  unsigned int max_width;

  total = 0;
  for (i = 0; i < n_bins; i++)
    total += bins[i];

  if (!total)
      return;

  /* 2 * ceil (log10(2) * (N - 1)) + 1  */
  max_width = 2 * (unsigned int)(0.30103 * (n_bins - 1) + 0.9999) + 1;

  fprintf (file, "%s %s", name, msg);
  for (i = 0; i < 2; i++)
    fprintf (file, "%*d\t%8d (%5.1f%%)\n",
	     max_width, i, bins[i], 100.0 * bins[i] / total);

  /* Perhaps we should bail out once the histogram goes to zero.  */
  for (; i < n_bins; i++)
    fprintf (file, "%*d-%d\t%8d (%5.1f%%)\n",
	     max_width - ((unsigned int) (0.30103 * (i) + 0.9999) + 1),
	     1 << (i - 1), (1 << i) - 1, bins[i], (100.0 * bins[i]) / total);
}


/* Print bitset statistics to FILE.  */
static void
bitset_stats_print_1 (file, name, stats)
     FILE *file;
     const char *name;
     struct bitset_type_stats_struct *stats;
{
  if (!stats)
    return;

  fprintf (file, "%d %ss xmalloced, %d freed.\n",
	   stats->xmallocs, name, stats->xfrees);
  fprintf (file, "%d %ss oballoced, %d freed.\n",
	   stats->oballocs, name, stats->obfrees);

  fprintf (file, "%d bitset_lists\n", stats->lists);

  bitset_log_histogram_print (file, name, "count log histogram\n",
	   BITSET_LOG_COUNT_BINS, stats->list_counts);

  bitset_log_histogram_print (file, name, "size log histogram\n",
	   BITSET_LOG_SIZE_BINS, stats->list_sizes);

  bitset_percent_histogram_print (file, name, "density histogram\n",
				  BITSET_DENSITY_BINS, stats->list_density);
}


/* Print all bitset statistics to FILE.  */
static void
bitset_stats_print (file, verbose)
     FILE *file;
     int verbose ATTRIBUTE_UNUSED;
{
  int i;
  static const char *names[] = BITSET__TYPE_NAMES;

  if (!bitset_stats)
    return;

  fprintf (file, "Bitset statistics:\n\n");

  if (bitset_stats->runs > 1)
    fprintf (file, "Accumulated runs = %d\n", bitset_stats->runs);

  for (i = 0; i < BITSET_TYPE_NUM; i++)
      bitset_stats_print_1 (file, names[i], &bitset_stats->types[i]);
}
#endif /* BITSET_STATS  */


/* Initialise bitset statistics logging.  */
void
bitset_stats_init ()
{
#if BITSET_STATS
    bitset_stats = &bitset_stats_data;
    bitset_stats_read ();
#endif  /* BITSET_STATS  */
}


/* Read bitset statistics file.  */
static void
bitset_stats_read ()
{
    FILE *file;

    if (!bitset_stats)
      return;

    file = fopen (BITSET_STATS_FILE, "r");
    if (file)
      {
	if (fread (&bitset_stats_data, sizeof (bitset_stats_data),
		   1, file) != 1)
	  {
	    if (ferror (file))
	      perror ("Could not read stats file");
	    else
	      fprintf (stderr, "Bad stats file size\n");
	  }
	fclose (file);
      }
    bitset_stats_data.runs++;
}


/* Write bitset statistics file.  */
static void
bitset_stats_write ()
{
    FILE *file;

    if (!bitset_stats)
      return;

    file = fopen (BITSET_STATS_FILE, "w");
    if (file)
      {
	if (fwrite (&bitset_stats_data, sizeof (bitset_stats_data),
		    1, file) != 1)
	  perror ("Could not write stats file");
	fclose (file);
      }
    else
      perror ("Could not open stats file for writing");
}


/* Dump bitset statistics to FILE.  */
void
bitset_stats_dump (file)
     FILE *file;
{
#if BITSET_STATS
  bitset_stats_print (file, 0);
  bitset_stats_write ();
#endif /* BITSET_STATS  */
}


/* Function to be called from debugger to print bitset stats.  */
void
debug_bitset_stats (void)
{
#if BITSET_STATS
  bitset_stats_print (stderr, 1);
#endif /* BITSET_STATS  */
}