lib/bitset.h

/* Generic bitsets.

   Copyright (C) 2002-2004, 2009-2015, 2018-2026 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 3 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, see <https://www.gnu.org/licenses/>.  */

#ifndef _GL_BITSET_H
#define _GL_BITSET_H

/* This file is the public interface to the bitset abstract data type.
   Only use the functions and macros defined in this file.  */

/* This file uses _GL_ATTRIBUTE_DEALLOC.  */
#if !_GL_CONFIG_H_INCLUDED
 #error "Please include config.h first."
#endif

#include <stdio.h>
#if USE_UNLOCKED_IO
# include "unlocked-io.h"
#endif

#include "bitset/base.h"
#include "obstack.h"

#ifdef __cplusplus
extern "C" {
#endif


/* Attributes used to select a bitset implementation.  */
enum bitset_attr {BITSET_FIXED = 1,    /* Bitset size fixed.  */
                  BITSET_VARIABLE = 2, /* Bitset size variable.  */
                  BITSET_DENSE = 4,    /* Bitset dense.  */
                  BITSET_SPARSE = 8,   /* Bitset sparse.  */
                  BITSET_FRUGAL = 16,  /* Prefer most compact.  */
                  BITSET_GREEDY = 32}; /* Prefer fastest at memory expense.  */

typedef unsigned bitset_attrs;

/* The contents of the union should be considered to be private.
   While I would like to make this union opaque, it needs to be
   visible for the inline bit set/test functions, and for delegation
   to the proper implementation.  */
union bitset_union
{
  /* This must be the first member of every other structure that is a
     member of this union.  */
  struct bbitset_struct b;              /* Base bitset data.  */

  struct abitset_struct
  {
    struct bbitset_struct b;
    bitset_word words[1];               /* The array of bits.  */
  } a;

  struct tbitset_struct
  {
    struct bbitset_struct b;
    bitset_windex size;                 /* Number of elements.  */
    struct tbitset_elt_struct **elts;   /* Expanding array of ptrs to elts.  */
  } e;

  struct lbitset_struct
  {
    struct bbitset_struct b;
    struct lbitset_elt_struct *head;    /* First element in linked list.  */
    struct lbitset_elt_struct *tail;    /* Last element in linked list.  */
  } l;

  struct bitset_stats_struct
  {
    struct bbitset_struct b;
    bitset bset;
  } s;

  struct vbitset_struct
  {
    struct bbitset_struct b;
    bitset_windex size;                 /* Allocated size of array.  */
  } v;
};


/* The contents of this structure should be considered private.
   It is used for iterating over set bits.  */
typedef struct
{
  bitset_bindex list[BITSET_LIST_SIZE];
  bitset_bindex next;
  bitset_bindex num;
  bitset_bindex i;
} bitset_iterator;


/* Free bitset.  Do nothing if NULL.  */
void bitset_free (bitset);

/* Return bytes required for bitset of desired type and size.  */
size_t bitset_bytes (enum bitset_type, bitset_bindex);

/* Initialise a bitset with desired type and size.  */
bitset bitset_init (bitset, bitset_bindex, enum bitset_type);

/* Select an implementation type based on the desired bitset size
   and attributes.  */
enum bitset_type bitset_type_choose (bitset_bindex, bitset_attrs);

/* Create a bitset of desired type and size.  The bitset is zeroed.  */
bitset bitset_alloc (bitset_bindex, enum bitset_type)
  _GL_ATTRIBUTE_DEALLOC (bitset_free, 1);

/* Free bitset allocated on obstack.  Do nothing if NULL.  */
void bitset_obstack_free (bitset);

/* Create a bitset of desired type and size using an obstack.  The
   bitset is zeroed.  */
bitset bitset_obstack_alloc (struct obstack *bobstack,
                             bitset_bindex, enum bitset_type)
  _GL_ATTRIBUTE_DEALLOC (bitset_obstack_free, 1);

/* Create a bitset of desired size and attributes.  The bitset is zeroed.  */
bitset bitset_create (bitset_bindex, bitset_attrs)
  _GL_ATTRIBUTE_DEALLOC (bitset_free, 1);

/* Return bitset type.  */
enum bitset_type bitset_type_get (bitset);

/* Return bitset type name.  */
const char *bitset_type_name_get (bitset);


/* Set bit BITNO in bitset BSET.  */
static inline void
bitset_set (bitset bset, bitset_bindex bitno)
{
  bitset_windex windex = bitno / BITSET_WORD_BITS;
  bitset_windex offset = windex - bset->b.cindex;

  if (offset < bset->b.csize)
    bset->b.cdata[offset] |= ((bitset_word) 1 << (bitno % BITSET_WORD_BITS));
  else
    BITSET_SET_ (bset, bitno);
}


/* Reset bit BITNO in bitset BSET.  */
static inline void
bitset_reset (bitset bset, bitset_bindex bitno)
{
  bitset_windex windex = bitno / BITSET_WORD_BITS;
  bitset_windex offset = windex - bset->b.cindex;

  if (offset < bset->b.csize)
    bset->b.cdata[offset] &= ~((bitset_word) 1 << (bitno % BITSET_WORD_BITS));
  else
    BITSET_RESET_ (bset, bitno);
}


/* Test bit BITNO in bitset BSET.  */
static inline bool
bitset_test (bitset bset, bitset_bindex bitno)
{
  bitset_windex windex = bitno / BITSET_WORD_BITS;
  bitset_windex offset = windex - bset->b.cindex;

  if (offset < bset->b.csize)
    return (bset->b.cdata[offset] >> (bitno % BITSET_WORD_BITS)) & 1;
  else
    return BITSET_TEST_ (bset, bitno);
}


/* Toggle bit BITNO in bitset BSET and return non-zero if now set.  */
#define bitset_toggle(bset, bitno) BITSET_TOGGLE_ (bset, bitno)

/* Return size in bits of bitset SRC.  */
#define bitset_size(SRC) BITSET_SIZE_ (SRC)

/* Change size in bits of bitset.  New bits are zeroed.  Return
   SIZE.  */
#define bitset_resize(DST, SIZE) BITSET_RESIZE_ (DST, SIZE)

/* Return number of bits set in bitset SRC.  */
#define bitset_count(SRC) BITSET_COUNT_ (SRC)


/* Return SRC == 0.  */
#define bitset_empty_p(SRC) BITSET_EMPTY_P_ (SRC)

/* DST = ~0.  */
#define bitset_ones(DST) BITSET_ONES_ (DST)

/* DST = 0.  */
#define bitset_zero(DST) BITSET_ZERO_ (DST)



/* DST = SRC.  */
#define bitset_copy(DST, SRC) BITSET_COPY_ (DST, SRC)

/* Return DST & SRC == 0.  */
#define bitset_disjoint_p(DST, SRC) BITSET_DISJOINT_P_ (DST, SRC)

/* Return DST == SRC.  */
#define bitset_equal_p(DST, SRC) BITSET_EQUAL_P_ (DST, SRC)

/* DST = ~SRC.  */
#define bitset_not(DST, SRC) BITSET_NOT_ (DST, SRC)

/* Return DST == DST | SRC.  */
#define bitset_subset_p(DST, SRC) BITSET_SUBSET_P_ (DST, SRC)



/* DST = SRC1 & SRC2.  */
#define bitset_and(DST, SRC1, SRC2) BITSET_AND_ (DST, SRC1, SRC2)

/* DST = SRC1 & SRC2.  Return non-zero if DST != SRC1 & SRC2.  */
#define bitset_and_cmp(DST, SRC1, SRC2) BITSET_AND_CMP_ (DST, SRC1, SRC2)

/* DST = SRC1 & ~SRC2.  */
#define bitset_andn(DST, SRC1, SRC2) BITSET_ANDN_ (DST, SRC1, SRC2)

/* DST = SRC1 & ~SRC2.  Return non-zero if DST != SRC1 & ~SRC2.  */
#define bitset_andn_cmp(DST, SRC1, SRC2) BITSET_ANDN_CMP_ (DST, SRC1, SRC2)

/* DST = SRC1 | SRC2.  */
#define bitset_or(DST, SRC1, SRC2) BITSET_OR_ (DST, SRC1, SRC2)

/* DST = SRC1 | SRC2.  Return non-zero if DST != SRC1 | SRC2.  */
#define bitset_or_cmp(DST, SRC1, SRC2) BITSET_OR_CMP_ (DST, SRC1, SRC2)

/* DST = SRC1 ^ SRC2.  */
#define bitset_xor(DST, SRC1, SRC2) BITSET_XOR_ (DST, SRC1, SRC2)

/* DST = SRC1 ^ SRC2.  Return non-zero if DST != SRC1 ^ SRC2.  */
#define bitset_xor_cmp(DST, SRC1, SRC2) BITSET_XOR_CMP_ (DST, SRC1, SRC2)



/* DST = (SRC1 & SRC2) | SRC3.  */
#define bitset_and_or(DST, SRC1, SRC2, SRC3) \
 BITSET_AND_OR_ (DST, SRC1, SRC2, SRC3)

/* DST = (SRC1 & SRC2) | SRC3.  Return non-zero if
   DST != (SRC1 & SRC2) | SRC3.  */
#define bitset_and_or_cmp(DST, SRC1, SRC2, SRC3) \
 BITSET_AND_OR_CMP_ (DST, SRC1, SRC2, SRC3)

/* DST = (SRC1 & ~SRC2) | SRC3.  */
#define bitset_andn_or(DST, SRC1, SRC2, SRC3) \
 BITSET_ANDN_OR_ (DST, SRC1, SRC2, SRC3)

/* DST = (SRC1 & ~SRC2) | SRC3.  Return non-zero if
   DST != (SRC1 & ~SRC2) | SRC3.  */
#define bitset_andn_or_cmp(DST, SRC1, SRC2, SRC3) \
 BITSET_ANDN_OR_CMP_ (DST, SRC1, SRC2, SRC3)

/* DST = (SRC1 | SRC2) & SRC3.  */
#define bitset_or_and(DST, SRC1, SRC2, SRC3)\
 BITSET_OR_AND_ (DST, SRC1, SRC2, SRC3)

/* DST = (SRC1 | SRC2) & SRC3.  Return non-zero if
   DST != (SRC1 | SRC2) & SRC3.  */
#define bitset_or_and_cmp(DST, SRC1, SRC2, SRC3)\
 BITSET_OR_AND_CMP_ (DST, SRC1, SRC2, SRC3)

/* Find list of up to NUM bits set in BSET starting from and including
   *NEXT.  Return with actual number of bits found and with *NEXT
   indicating where search stopped.  */
#define bitset_list(BSET, LIST, NUM, NEXT) \
 BITSET_LIST_ (BSET, LIST, NUM, NEXT)

/* Find reverse list of up to NUM bits set in BSET starting from and
   including NEXT.  Return with actual number of bits found and with
   *NEXT indicating where search stopped.  */
#define bitset_list_reverse(BSET, LIST, NUM, NEXT) \
 BITSET_LIST_REVERSE_ (BSET, LIST, NUM, NEXT)

/* Return true if both bitsets are of the same type and size.  */
bool bitset_compatible_p (bitset bset1, bitset bset2);

/* Find next bit set in SRC starting from and including BITNO.
   Return BITSET_BINDEX_MAX if SRC empty.  */
bitset_bindex bitset_next (bitset src, bitset_bindex bitno);

/* Find previous bit set in SRC starting from and including BITNO.
   Return BITSET_BINDEX_MAX if SRC empty.  */
bitset_bindex bitset_prev (bitset src, bitset_bindex bitno);

/* Find first set bit.
   Return BITSET_BINDEX_MAX if SRC empty.  */
bitset_bindex bitset_first (bitset src);

/* Find last set bit.
   Return BITSET_BINDEX_MAX if SRC empty.  */
bitset_bindex bitset_last (bitset src);

/* Return nonzero if this is the only set bit.  */
bool bitset_only_set_p (bitset, bitset_bindex);

/* Dump bitset.  */
void bitset_dump (FILE *, bitset);

/* Loop over all elements of BSET, starting with MIN, setting INDEX
   to the index of each set bit.  For example, the following will print
   the bits set in a bitset:

   bitset_bindex i;
   bitset_iterator iter;

   BITSET_FOR_EACH (iter, src, i, 0)
     printf ("%lu ", (unsigned long) i);
*/
#define BITSET_FOR_EACH(ITER, BSET, INDEX, MIN)                               \
  for (ITER.next = (MIN), ITER.num = BITSET_LIST_SIZE;                        \
       (ITER.num == BITSET_LIST_SIZE)                                         \
       && (ITER.num = bitset_list (BSET, ITER.list,                           \
                                   BITSET_LIST_SIZE, &ITER.next));)           \
    for (ITER.i = 0;                                                          \
         ITER.i < ITER.num && ((INDEX) = ITER.list[ITER.i], 1);               \
         ITER.i++)


/* Loop over all elements of BSET, in reverse order starting with
   MIN, setting INDEX to the index of each set bit.  For example, the
   following will print the bits set in a bitset in reverse order:

   bitset_bindex i;
   bitset_iterator iter;

   BITSET_FOR_EACH_REVERSE (iter, src, i, 0)
    printf ("%lu ", (unsigned long) i);
*/
#define BITSET_FOR_EACH_REVERSE(ITER, BSET, INDEX, MIN)                       \
  for (ITER.next = (MIN), ITER.num = BITSET_LIST_SIZE;                        \
       (ITER.num == BITSET_LIST_SIZE)                                         \
       && (ITER.num = bitset_list_reverse (BSET, ITER.list,                   \
                                           BITSET_LIST_SIZE, &ITER.next));)   \
    for (ITER.i = 0;                                                          \
         ITER.i < ITER.num && ((INDEX) = ITER.list[ITER.i], 1);               \
         ITER.i++)


/* Define set operations in terms of logical operations.  */

#define bitset_diff(DST, SRC1, SRC2) bitset_andn (DST, SRC1, SRC2)
#define bitset_diff_cmp(DST, SRC1, SRC2) bitset_andn_cmp (DST, SRC1, SRC2)

#define bitset_intersection(DST, SRC1, SRC2) bitset_and (DST, SRC1, SRC2)
#define bitset_intersection_cmp(DST, SRC1, SRC2) bitset_and_cmp (DST, SRC1, SRC2)

#define bitset_union(DST, SRC1, SRC2) bitset_or (DST, SRC1, SRC2)
#define bitset_union_cmp(DST, SRC1, SRC2) bitset_or_cmp (DST, SRC1, SRC2)

/* Symmetrical difference.  */
#define bitset_symdiff(DST, SRC1, SRC2) bitset_xor (DST, SRC1, SRC2)
#define bitset_symdiff_cmp(DST, SRC1, SRC2) bitset_xor_cmp (DST, SRC1, SRC2)

/* Union of difference.  */
#define bitset_diff_union(DST, SRC1, SRC2, SRC3) \
  bitset_andn_or (DST, SRC1, SRC2, SRC3)
#define bitset_diff_union_cmp(DST, SRC1, SRC2, SRC3) \
  bitset_andn_or_cmp (DST, SRC1, SRC2, SRC3)


/* Release any memory tied up with bitsets.  */
void bitset_release_memory (void);

/* Enable bitset stats gathering.  */
void bitset_stats_enable (void);

/* Disable bitset stats gathering.  */
void bitset_stats_disable (void);

/* Read bitset stats file of accumulated stats.  */
void bitset_stats_read (const char *file_name);

/* Write bitset stats file of accumulated stats.  */
void bitset_stats_write (const char *file_name);

/* Dump bitset stats.  */
void bitset_stats_dump (FILE *);

/* Function to debug bitset from debugger.  */
void debug_bitset (bitset);

/* Function to debug bitset stats from debugger.  */
void debug_bitset_stats (void);


#ifdef __cplusplus
}
#endif

#endif /* _GL_BITSET_H  */