mirror of
https://github.com/MariaDB/server.git
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1ce1880204
* Fixed a problem with wrong query results for partially covering keys in ROR-index_merge * ROR-intersection retrieval plan choice algorithm now uses less disk IO - and properly processes clustered PK range scans * Fixed several minor range optimizer problems * Added more comments * Code cleanup mysql-test/r/index_merge.result: New index_merge EXPLAIN output format changes mysql-test/r/index_merge_innodb.result: New index_merge EXPLAIN output format changes mysql-test/r/index_merge_ror.result: New index_merge EXPLAIN output format changes Added test for scans on keys that cover fields partially Fixed a minor ROR optimizer problem mysql-test/r/index_merge_ror_cpk.result: More tests added mysql-test/t/index_merge_ror.test: New index_merge EXPLAIN output format changes Added test for scans on keys that cover fields partially Fixed a minor ROR optimizer problem mysql-test/t/index_merge_ror_cpk.test: More tests added mysys/my_bitmap.c: Comments added, code cleanup sql/opt_range.cc: Comments added, code cleanup Numerous fixes, see changeset description sql/opt_range.h: Comments added, code cleanup New index_merge EXPLAIN output format related changes sql/sql_select.cc: Comments added, code cleanup New index_merge EXPLAIN output
398 lines
8.5 KiB
C
398 lines
8.5 KiB
C
/* Copyright (C) 2000 MySQL AB
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
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/*
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Handling of uchar arrays as large bitmaps.
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API limitations (or, rather asserted safety assumptions,
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to encourage correct programming)
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* the size of the used bitmap is less than ~(uint) 0
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* it's a multiple of 8 (for efficiency reasons)
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* when arguments are a bitmap and a bit number, the number
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must be within bitmap size
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* bitmap_set_prefix() is an exception - one can use ~0 to set all bits
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* when both arguments are bitmaps, they must be of the same size
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* bitmap_intersect() is an exception :)
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(for for Bitmap::intersect(ulonglong map2buff))
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If THREAD is defined all bitmap operations except bitmap_init/bitmap_free
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are thread-safe.
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TODO:
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Make assembler THREAD safe versions of these using test-and-set instructions
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*/
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#include "mysys_priv.h"
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#include <my_bitmap.h>
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#include <assert.h>
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#include <m_string.h>
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inline void bitmap_lock(MY_BITMAP *map)
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{
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#ifdef THREAD
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if (map->mutex)
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pthread_mutex_lock(map->mutex);
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#endif
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}
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inline void bitmap_unlock(MY_BITMAP *map)
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{
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#ifdef THREAD
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if (map->mutex)
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pthread_mutex_unlock(map->mutex);
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#endif
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}
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my_bool bitmap_init(MY_BITMAP *map, uchar *buf, uint bitmap_size,
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my_bool thread_safe)
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{
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DBUG_ENTER("bitmap_init");
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DBUG_ASSERT((bitmap_size & 7) == 0);
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bitmap_size/=8;
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if (!(map->bitmap=buf) &&
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!(map->bitmap= (uchar*) my_malloc(bitmap_size +
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(thread_safe ?
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sizeof(pthread_mutex_t) : 0),
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MYF(MY_WME | MY_ZEROFILL))))
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return 1;
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map->bitmap_size=bitmap_size;
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#ifdef THREAD
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if (thread_safe)
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{
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map->mutex=(pthread_mutex_t *)(map->bitmap+bitmap_size);
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pthread_mutex_init(map->mutex, MY_MUTEX_INIT_FAST);
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}
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else
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map->mutex=0;
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#endif
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DBUG_RETURN(0);
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}
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void bitmap_free(MY_BITMAP *map)
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{
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DBUG_ENTER("bitmap_free");
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if (map->bitmap)
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{
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#ifdef THREAD
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if (map->mutex)
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pthread_mutex_destroy(map->mutex);
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#endif
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my_free((char*) map->bitmap, MYF(0));
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map->bitmap=0;
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}
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DBUG_VOID_RETURN;
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}
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void bitmap_set_bit(MY_BITMAP *map, uint bitmap_bit)
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{
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DBUG_ASSERT(map->bitmap && bitmap_bit < map->bitmap_size*8);
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bitmap_lock(map);
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map->bitmap[bitmap_bit / 8] |= (1 << (bitmap_bit & 7));
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bitmap_unlock(map);
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}
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uint bitmap_set_next(MY_BITMAP *map)
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{
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uchar *bitmap=map->bitmap;
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uint bit_found = MY_BIT_NONE;
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uint bitmap_size=map->bitmap_size*8;
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uint i;
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DBUG_ASSERT(map->bitmap);
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bitmap_lock(map);
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for (i=0; i < bitmap_size ; i++, bitmap++)
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{
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if (*bitmap != 0xff)
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{ /* Found slot with free bit */
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uint b;
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for (b=0; ; b++)
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{
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if (!(*bitmap & (1 << b)))
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{
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*bitmap |= 1<<b;
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bit_found = (i*8)+b;
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break;
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}
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}
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break; /* Found bit */
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}
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}
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bitmap_unlock(map);
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return bit_found;
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}
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void bitmap_clear_bit(MY_BITMAP *map, uint bitmap_bit)
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{
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DBUG_ASSERT(map->bitmap && bitmap_bit < map->bitmap_size*8);
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bitmap_lock(map);
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map->bitmap[bitmap_bit / 8] &= ~ (1 << (bitmap_bit & 7));
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bitmap_unlock(map);
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}
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void bitmap_set_prefix(MY_BITMAP *map, uint prefix_size)
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{
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uint prefix_bytes, prefix_bits;
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DBUG_ASSERT(map->bitmap &&
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(prefix_size <= map->bitmap_size*8 || prefix_size == (uint) ~0));
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bitmap_lock(map);
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set_if_smaller(prefix_size, map->bitmap_size*8);
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if ((prefix_bytes= prefix_size / 8))
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memset(map->bitmap, 0xff, prefix_bytes);
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if ((prefix_bits= prefix_size & 7))
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map->bitmap[prefix_bytes++]= (1 << prefix_bits)-1;
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if (prefix_bytes < map->bitmap_size)
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bzero(map->bitmap+prefix_bytes, map->bitmap_size-prefix_bytes);
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bitmap_unlock(map);
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}
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void bitmap_clear_all(MY_BITMAP *map)
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{
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bitmap_set_prefix(map, 0);
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}
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void bitmap_set_all(MY_BITMAP *map)
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{
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bitmap_set_prefix(map, ~0);
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}
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my_bool bitmap_is_prefix(const MY_BITMAP *map, uint prefix_size)
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{
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uint prefix_bits= prefix_size & 7, res= 0;
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uchar *m= map->bitmap, *end_prefix= map->bitmap+prefix_size/8,
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*end= map->bitmap+map->bitmap_size;
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DBUG_ASSERT(map->bitmap && prefix_size <= map->bitmap_size*8);
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bitmap_lock((MY_BITMAP *)map);
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while (m < end_prefix)
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if (*m++ != 0xff)
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goto ret;
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if (prefix_bits && *m++ != (1 << prefix_bits)-1)
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goto ret;
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while (m < end)
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if (*m++ != 0)
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goto ret;
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res=1;
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ret:
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bitmap_unlock((MY_BITMAP *)map);
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return res;
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}
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my_bool bitmap_is_clear_all(const MY_BITMAP *map)
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{
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return bitmap_is_prefix(map, 0);
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}
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my_bool bitmap_is_set_all(const MY_BITMAP *map)
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{
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return bitmap_is_prefix(map, map->bitmap_size*8);
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}
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my_bool bitmap_is_set(const MY_BITMAP *map, uint bitmap_bit)
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{
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DBUG_ASSERT(map->bitmap && bitmap_bit < map->bitmap_size*8);
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return map->bitmap[bitmap_bit / 8] & (1 << (bitmap_bit & 7));
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}
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my_bool bitmap_is_subset(const MY_BITMAP *map1, const MY_BITMAP *map2)
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{
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uint res=0;
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uchar *m1=map1->bitmap, *m2=map2->bitmap, *end;
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DBUG_ASSERT(map1->bitmap && map2->bitmap &&
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map1->bitmap_size==map2->bitmap_size);
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bitmap_lock((MY_BITMAP *)map1);
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bitmap_lock((MY_BITMAP *)map2);
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end= m1+map1->bitmap_size;
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while (m1 < end)
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{
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if ((*m1++) & ~(*m2++))
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goto ret;
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}
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res=1;
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ret:
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bitmap_unlock((MY_BITMAP *)map2);
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bitmap_unlock((MY_BITMAP *)map1);
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return res;
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}
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my_bool bitmap_cmp(const MY_BITMAP *map1, const MY_BITMAP *map2)
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{
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uint res;
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DBUG_ASSERT(map1->bitmap && map2->bitmap &&
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map1->bitmap_size==map2->bitmap_size);
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bitmap_lock((MY_BITMAP *)map1);
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bitmap_lock((MY_BITMAP *)map2);
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res= memcmp(map1->bitmap, map2->bitmap, map1->bitmap_size)==0;
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bitmap_unlock((MY_BITMAP *)map2);
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bitmap_unlock((MY_BITMAP *)map1);
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return res;
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}
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void bitmap_intersect(MY_BITMAP *map, const MY_BITMAP *map2)
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{
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uchar *to=map->bitmap, *from=map2->bitmap, *end;
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uint len=map->bitmap_size, len2=map2->bitmap_size;
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DBUG_ASSERT(map->bitmap && map2->bitmap);
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bitmap_lock(map);
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bitmap_lock((MY_BITMAP *)map2);
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end= to+min(len,len2);
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while (to < end)
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*to++ &= *from++;
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if (len2 < len)
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{
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end+=len-len2;
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while (to < end)
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*to++=0;
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}
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bitmap_unlock((MY_BITMAP *)map2);
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bitmap_unlock(map);
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}
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void bitmap_subtract(MY_BITMAP *map, const MY_BITMAP *map2)
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{
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uchar *to=map->bitmap, *from=map2->bitmap, *end;
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DBUG_ASSERT(map->bitmap && map2->bitmap &&
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map->bitmap_size==map2->bitmap_size);
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bitmap_lock(map);
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bitmap_lock((MY_BITMAP *)map2);
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end= to+map->bitmap_size;
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while (to < end)
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*to++ &= ~(*from++);
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bitmap_unlock((MY_BITMAP *)map2);
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bitmap_unlock(map);
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}
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void bitmap_union(MY_BITMAP *map, const MY_BITMAP *map2)
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{
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uchar *to=map->bitmap, *from=map2->bitmap, *end;
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DBUG_ASSERT(map->bitmap && map2->bitmap &&
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map->bitmap_size==map2->bitmap_size);
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bitmap_lock(map);
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bitmap_lock((MY_BITMAP *)map2);
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end= to+map->bitmap_size;
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while (to < end)
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*to++ |= *from++;
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bitmap_unlock((MY_BITMAP *)map2);
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bitmap_unlock(map);
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}
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/*
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SYNOPSIS
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bitmap_bits_set()
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map
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RETURN
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Number of set bits in the bitmap.
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*/
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uint bitmap_bits_set(const MY_BITMAP *map)
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{
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uchar *m= map->bitmap;
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uchar *end= m + map->bitmap_size;
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uint res= 0;
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DBUG_ASSERT(map->bitmap);
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bitmap_lock((MY_BITMAP *)map);
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while (m < end)
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{
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res+= my_count_bits_ushort(*m++);
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}
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bitmap_unlock((MY_BITMAP *)map);
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return res;
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}
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/*
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SYNOPSIS
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bitmap_get_first()
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map
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RETURN
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Number of first unset bit in the bitmap or MY_BIT_NONE if all bits are set.
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*/
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uint bitmap_get_first(const MY_BITMAP *map)
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{
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uchar *bitmap=map->bitmap;
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uint bit_found = MY_BIT_NONE;
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uint bitmap_size=map->bitmap_size*8;
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uint i;
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DBUG_ASSERT(map->bitmap);
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bitmap_lock((MY_BITMAP *)map);
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for (i=0; i < bitmap_size ; i++, bitmap++)
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{
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if (*bitmap != 0xff)
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{ /* Found slot with free bit */
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uint b;
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for (b=0; ; b++)
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{
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if (!(*bitmap & (1 << b)))
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{
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bit_found = (i*8)+b;
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break;
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}
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}
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break; /* Found bit */
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}
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}
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bitmap_unlock((MY_BITMAP *)map);
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return bit_found;
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}
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