MySQL 8.0.30
Source Code Documentation
my_bitmap.cc File Reference

Handling of uchar arrays as large bitmaps. More...

#include <string.h>
#include <sys/types.h>
#include <algorithm>
#include "my_bit.h"
#include "my_bitmap.h"
#include "my_byteorder.h"
#include "my_dbug.h"
#include "my_inttypes.h"
#include "my_macros.h"
#include "my_sys.h"
#include "mysql/service_mysql_alloc.h"
#include "mysys/mysys_priv.h"

Functions

void create_last_word_mask (MY_BITMAP *map)
 
static uint get_first_set (uint32 value, uint word_pos)
 
static uint get_first_not_set (uint32 value, uint word_pos)
 
bool bitmap_init (MY_BITMAP *map, my_bitmap_map *buf, uint n_bits)
 
void bitmap_free (MY_BITMAP *map)
 
bool bitmap_test_and_set (MY_BITMAP *map, uint bitmap_bit)
 
uint bitmap_set_next (MY_BITMAP *map)
 
void bitmap_set_prefix (MY_BITMAP *map, uint prefix_size)
 Set the specified number of bits in the bitmap buffer. More...
 
bool bitmap_is_prefix (const MY_BITMAP *map, uint prefix_size)
 
bool bitmap_is_set_all (const MY_BITMAP *map)
 
bool bitmap_is_clear_all (const MY_BITMAP *map)
 
bool bitmap_is_subset (const MY_BITMAP *map1, const MY_BITMAP *map2)
 
bool bitmap_is_overlapping (const MY_BITMAP *map1, const MY_BITMAP *map2)
 
bool bitmap_is_valid (const MY_BITMAP *map)
 Check if 'map' is valid. More...
 
void bitmap_intersect (MY_BITMAP *to, const MY_BITMAP *from)
 
void bitmap_set_above (MY_BITMAP *map, uint from_byte, bool use_bit)
 
void bitmap_subtract (MY_BITMAP *map, const MY_BITMAP *map2)
 
void bitmap_union (MY_BITMAP *map, const MY_BITMAP *map2)
 
void bitmap_xor (MY_BITMAP *map, const MY_BITMAP *map2)
 
void bitmap_invert (MY_BITMAP *map)
 
uint bitmap_bits_set (const MY_BITMAP *map)
 
void bitmap_copy (MY_BITMAP *map, const MY_BITMAP *map2)
 
uint bitmap_get_first_set (const MY_BITMAP *map)
 
uint bitmap_get_next_set (const MY_BITMAP *map, uint bitmap_bit)
 Get the next set bit. More...
 
uint bitmap_get_first (const MY_BITMAP *map)
 
uint bitmap_n_copy (MY_BITMAP *dst, const MY_BITMAP *src, uint max_bits_to_copy)
 Copy as many bits as 'dst' can hold from 'src', but no more than max_bits_to_copy bits. More...
 

Detailed Description

Handling of uchar arrays as large bitmaps.

API limitations (or, rather asserted safety assumptions, to encourage correct programming)

the internal size is a set of 32 bit words
the number of bits specified in creation can be any number > 0
a bitmap with zero bits can be created and initialized, but not used.

TODO: Make assembler THREAD safe versions of these using test-and-set instructions

Original version created by Sergei Golubchik 2001 - 2004. New version written and test program added and some changes to the interface was made by Mikael Ronström 2005, with assistance of Tomas Ulin and Mats Kindahl.

Function Documentation

◆ bitmap_bits_set()

uint bitmap_bits_set ( const MY_BITMAP map)

◆ bitmap_copy()

void bitmap_copy ( MY_BITMAP map,
const MY_BITMAP map2 
)

◆ bitmap_free()

void bitmap_free ( MY_BITMAP map)

◆ bitmap_get_first()

uint bitmap_get_first ( const MY_BITMAP map)

◆ bitmap_get_first_set()

uint bitmap_get_first_set ( const MY_BITMAP map)

◆ bitmap_get_next_set()

uint bitmap_get_next_set ( const MY_BITMAP map,
uint  bitmap_bit 
)

Get the next set bit.

Parameters
mapBitmap
bitmap_bitBit to start search from
Returns
Index to first bit set after bitmap_bit

◆ bitmap_init()

bool bitmap_init ( MY_BITMAP map,
my_bitmap_map buf,
uint  n_bits 
)

◆ bitmap_intersect()

void bitmap_intersect ( MY_BITMAP to,
const MY_BITMAP from 
)

◆ bitmap_invert()

void bitmap_invert ( MY_BITMAP map)

◆ bitmap_is_clear_all()

bool bitmap_is_clear_all ( const MY_BITMAP map)

◆ bitmap_is_overlapping()

bool bitmap_is_overlapping ( const MY_BITMAP map1,
const MY_BITMAP map2 
)

◆ bitmap_is_prefix()

bool bitmap_is_prefix ( const MY_BITMAP map,
uint  prefix_size 
)

◆ bitmap_is_set_all()

bool bitmap_is_set_all ( const MY_BITMAP map)

◆ bitmap_is_subset()

bool bitmap_is_subset ( const MY_BITMAP map1,
const MY_BITMAP map2 
)

◆ bitmap_is_valid()

bool bitmap_is_valid ( const MY_BITMAP map)

Check if 'map' is valid.

Parameters
mapThe map that we wish to verify.
Returns
'true' if 'map' passes a consistency check.

◆ bitmap_n_copy()

uint bitmap_n_copy ( MY_BITMAP dst,
const MY_BITMAP src,
uint  max_bits_to_copy 
)

Copy as many bits as 'dst' can hold from 'src', but no more than max_bits_to_copy bits.

'src' and 'dst' should not overlap. If 'dst' and 'src' have the same size (in bits), and this is less or equal than max_bits_to_copy, this function behaves identical to bitmap_copy().

Parameters
dstThe destination bitmap.
srcThe source bitmap.
max_bits_to_copyThe maximal number of bits to copy.
Returns
The number of bits copied.

◆ bitmap_set_above()

void bitmap_set_above ( MY_BITMAP map,
uint  from_byte,
bool  use_bit 
)

◆ bitmap_set_next()

uint bitmap_set_next ( MY_BITMAP map)

◆ bitmap_set_prefix()

void bitmap_set_prefix ( MY_BITMAP map,
uint  prefix_size 
)

Set the specified number of bits in the bitmap buffer.

Parameters
mapBitmap
prefix_sizeNumber of bits to be set

◆ bitmap_subtract()

void bitmap_subtract ( MY_BITMAP map,
const MY_BITMAP map2 
)

◆ bitmap_test_and_set()

bool bitmap_test_and_set ( MY_BITMAP map,
uint  bitmap_bit 
)

◆ bitmap_union()

void bitmap_union ( MY_BITMAP map,
const MY_BITMAP map2 
)

◆ bitmap_xor()

void bitmap_xor ( MY_BITMAP map,
const MY_BITMAP map2 
)

◆ create_last_word_mask()

void create_last_word_mask ( MY_BITMAP map)

◆ get_first_not_set()

static uint get_first_not_set ( uint32  value,
uint  word_pos 
)
inlinestatic

◆ get_first_set()

static uint get_first_set ( uint32  value,
uint  word_pos 
)
inlinestatic