mariadb/mysys/my_bit.c
unknown 3600d09ab4 This is first cset for WL#1394 "Optimize index merge when all involved index ranges include only values with equal keys"
The main idea is to exploit the fact that key scans for "key=const" return ordered sequences of rowids.


include/my_base.h:
  Added HA_EXTRA_KEYREAD_PRESERVE_FIELDS flag
include/my_bitmap.h:
  Added a couple of utility functions
include/my_sys.h:
  Added my_conunt_bits_ushort function
innobase/include/row0mysql.h:
  Added support for HA_EXTRA_KEYREAD_PRESERVE_FIELDS
innobase/row/row0sel.c:
  Added support for HA_EXTRA_KEYREAD_PRESERVE_FIELDS
mysys/my_bit.c:
  Added my_count_bits_ushort function
mysys/my_bitmap.c:
  Added a couple of utility functions
sql/ha_berkeley.cc:
  Added cmp_ref rowid comparison function.
sql/ha_berkeley.h:
  Added cmp_ref rowid comparison function.
sql/ha_heap.h:
  Added cmp_ref rowid comparison function.
sql/ha_innodb.cc:
  Added cmp_ref rowid comparison function and support from HA_EXTRA_KEYREAD_PRESERVE_FIELDS
sql/ha_innodb.h:
  Added cmp_ref rowid comparison function.
sql/handler.h:
  Added cmp_ref rowid comparison function.
sql/opt_range.cc:
  Added QUICK_ROR_{INTERSECT,UNION}_SELECT classes and related optimizer code
sql/opt_range.h:
  Added QUICK_ROR_{INTERSECT,UNION}_SELECT classes
sql/sql_delete.cc:
  Changed to use new ROWID comparison function
  also always call quick->reset() for quick selects
sql/sql_select.cc:
  Account for new quick select types
sql/sql_select.h:
  New, proper rowid ordering/comparison function to be used with Unique class etc.
sql/sql_test.cc:
  Account for new quick select types
sql/sql_update.cc:
  Account for new quick select types
2004-05-13 01:38:40 +04:00

78 lines
2.7 KiB
C

/* Copyright (C) 2000 MySQL AB
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 */
/* Some useful bit functions */
#include "mysys_priv.h"
/*
Find smallest X in 2^X >= value
This can be used to divide a number with value by doing a shift instead
*/
uint my_bit_log2(ulong value)
{
uint bit;
for (bit=0 ; value > 1 ; value>>=1, bit++) ;
return bit;
}
static char nbits[256] = {
0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8,
};
uint my_count_bits(ulonglong v)
{
#if SIZEOF_LONG_LONG > 4
/* The following code is a bit faster on 16 bit machines than if we would
only shift v */
ulong v2=(ulong) (v >> 32);
return (uint) (uchar) (nbits[(uchar) v] +
nbits[(uchar) (v >> 8)] +
nbits[(uchar) (v >> 16)] +
nbits[(uchar) (v >> 24)] +
nbits[(uchar) (v2)] +
nbits[(uchar) (v2 >> 8)] +
nbits[(uchar) (v2 >> 16)] +
nbits[(uchar) (v2 >> 24)]);
#else
return (uint) (uchar) (nbits[(uchar) v] +
nbits[(uchar) (v >> 8)] +
nbits[(uchar) (v >> 16)] +
nbits[(uchar) (v >> 24)]);
#endif
}
uint my_count_bits_ushort(ushort v)
{
return nbits[v];
}