mariadb/sql/sql_crypt.h
Davi Arnaut e53ecf2dc2 Bug#49141: Encode function is significantly slower in 5.1 compared to 5.0
The problem was that the multiple evaluations of a ENCODE or
DECODE function within a single statement caused the random
generator to be reinitialized at each evaluation, even though
the parameters were constants.

The solution is to initialize the random generator only once
if the password (seed) parameter is constant.

This patch borrows code and ideas from Georgi Kodinov's patch.

mysql-test/r/func_str.result:
  Add test case result.
mysql-test/r/ps.result:
  Add test case result.
mysql-test/t/func_str.test:
  Add test case for Bug#49141
mysql-test/t/ps.test:
  Add test case for Bug#49141
sql/item_strfunc.cc:
  Move seed generation code to a separate method.
  Seed only once if the password (seed) argument
  is constant.
  Remove duplicated code and use a transform method
  to apply encoding or decoding.
sql/item_strfunc.h:
  Add parameter to signal whether the PRNG is already seeded.
  Introduce transform method.
  Combine val_str methods.
sql/sql_crypt.cc:
  Remove method.
sql/sql_crypt.h:
  Seed is supplied as two long integers.
2009-12-04 13:36:58 -02:00

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/* Copyright (C) 2000-2001, 2005 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; 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
#ifdef USE_PRAGMA_INTERFACE
#pragma interface /* gcc class implementation */
#endif
class SQL_CRYPT :public Sql_alloc
{
struct rand_struct rand,org_rand;
char decode_buff[256],encode_buff[256];
uint shift;
public:
SQL_CRYPT() {}
SQL_CRYPT(ulong *seed)
{
init(seed);
}
~SQL_CRYPT() {}
void init(ulong *seed);
void reinit() { shift=0; rand=org_rand; }
void encode(char *str, uint length);
void decode(char *str, uint length);
};