my_bitmap.h

/*
   Copyright (c) 2001, 2015, Oracle and/or its affiliates. All rights reserved.

   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; version 2 of the License.

   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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA */

#ifndef _my_bitmap_h_
#define _my_bitmap_h_

#define MY_BIT_NONE (~(uint) 0)

#include <m_string.h>
#include "mysql/psi/mysql_thread.h"   /* mysql_mutex_t */

typedef uint32 my_bitmap_map;

typedef struct st_bitmap
{
  my_bitmap_map *bitmap;
  uint n_bits; /* number of bits occupied by the above */
  my_bitmap_map last_word_mask;
  my_bitmap_map *last_word_ptr;
  /*
     mutex will be acquired for the duration of each bitmap operation if
     thread_safe flag in bitmap_init was set.  Otherwise, we optimize by not
     acquiring the mutex
   */
  mysql_mutex_t *mutex;
} MY_BITMAP;

#ifdef	__cplusplus
extern "C" {
#endif
extern void create_last_word_mask(MY_BITMAP *map);
extern my_bool bitmap_init(MY_BITMAP *map, my_bitmap_map *buf, uint n_bits,
                           my_bool thread_safe);
extern my_bool bitmap_is_clear_all(const MY_BITMAP *map);
extern my_bool bitmap_is_prefix(const MY_BITMAP *map, uint prefix_size);
extern my_bool bitmap_is_set_all(const MY_BITMAP *map);
extern my_bool bitmap_is_subset(const MY_BITMAP *map1, const MY_BITMAP *map2);
extern my_bool bitmap_is_overlapping(const MY_BITMAP *map1,
                                     const MY_BITMAP *map2);
extern my_bool bitmap_test_and_set(MY_BITMAP *map, uint bitmap_bit);
extern my_bool bitmap_test_and_clear(MY_BITMAP *map, uint bitmap_bit);
extern my_bool bitmap_fast_test_and_set(MY_BITMAP *map, uint bitmap_bit);
extern uint bitmap_set_next(MY_BITMAP *map);
extern uint bitmap_get_first(const MY_BITMAP *map);
extern uint bitmap_get_first_set(const MY_BITMAP *map);
extern uint bitmap_get_next_set(const MY_BITMAP *map, uint bitmap_bit);
extern uint bitmap_bits_set(const MY_BITMAP *map);
extern void bitmap_free(MY_BITMAP *map);
extern void bitmap_set_above(MY_BITMAP *map, uint from_byte, uint use_bit);
extern void bitmap_set_prefix(MY_BITMAP *map, uint prefix_size);
extern void bitmap_intersect(MY_BITMAP *map, const MY_BITMAP *map2);
extern void bitmap_subtract(MY_BITMAP *map, const MY_BITMAP *map2);
extern void bitmap_union(MY_BITMAP *map, const MY_BITMAP *map2);
extern void bitmap_xor(MY_BITMAP *map, const MY_BITMAP *map2);
extern void bitmap_invert(MY_BITMAP *map);
extern void bitmap_copy(MY_BITMAP *map, const MY_BITMAP *map2);

extern uint bitmap_lock_set_next(MY_BITMAP *map);
extern void bitmap_lock_clear_bit(MY_BITMAP *map, uint bitmap_bit);
/* Fast, not thread safe, bitmap functions */
#define bitmap_buffer_size(bits) (((bits)+31)/32)*4
#define no_bytes_in_map(map) (((map)->n_bits + 7)/8)
#define no_words_in_map(map) (((map)->n_bits + 31)/32)

static inline void bitmap_set_bit(MY_BITMAP *map, uint bit)
{
  DBUG_ASSERT(bit < map->n_bits);
  ((uchar*)map->bitmap)[bit / 8] |= (1 << (bit & 7));
}


static inline void bitmap_flip_bit(MY_BITMAP *map, uint bit)
{
  DBUG_ASSERT(bit < map->n_bits);
  ((uchar*)map->bitmap)[bit / 8] ^= (1 << (bit & 7));
}


static inline void bitmap_clear_bit(MY_BITMAP *map, uint bit)
{
  DBUG_ASSERT(bit < map->n_bits);
  ((uchar*)map->bitmap)[bit / 8] &= ~(1 << (bit & 7));
}


static inline my_bool bitmap_is_set(const MY_BITMAP *map, uint bit)
{
  DBUG_ASSERT(bit < map->n_bits);
  return ((uchar*)map->bitmap)[bit / 8] & (1 << (bit & 7));
}

/**
   Quite unlike other C comparison functions ending with 'cmp', e.g. memcmp(),
   strcmp(), this function returns true if the bitmaps are equal, and false
   otherwise.

   @retval true The bitmaps are equal.
   @retval false The bitmaps differ.
 */
static inline my_bool bitmap_cmp(const MY_BITMAP *map1, const MY_BITMAP *map2)
{
  DBUG_ASSERT(map1->n_bits > 0);
  DBUG_ASSERT(map2->n_bits > 0);

  if (memcmp(map1->bitmap, map2->bitmap, 4*(no_words_in_map(map1)-1)) != 0)
    return FALSE;
  return ((*map1->last_word_ptr | map1->last_word_mask) ==
          (*map2->last_word_ptr | map2->last_word_mask));
}

/*
  Clears all bits. This is allowed even for a zero-size bitmap.
 */
static inline void bitmap_clear_all(MY_BITMAP *map)
{
  memset(map->bitmap, 0, 4 * no_words_in_map(map));
}

/*
  Sets all bits. This is allowed even for a zero-size bitmap.
 */
static inline void bitmap_set_all(MY_BITMAP *map)
{
  memset(map->bitmap, 0xFF, 4 * no_words_in_map(map));
}

#ifdef	__cplusplus
}
#endif

#endif /* _my_bitmap_h_ */