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/* Copyright (C) 2007 MySQL AB & Michael Widenius
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 */
#include "mysys_priv.h"
#include <m_string.h>
/*
Initialize random generator
NOTES
MySQL's password checks depends on this, so don't do any changes
that changes the random numbers that are generated!
*/
void my_rnd_init(struct my_rnd_struct *rand_st, ulong seed1, ulong seed2)
{
#ifdef HAVE_valgrind
bzero((char*) rand_st,sizeof(*rand_st)); /* Avoid UMC varnings */
#endif
rand_st->max_value= 0x3FFFFFFFL;
rand_st->max_value_dbl=(double) rand_st->max_value;
rand_st->seed1=seed1%rand_st->max_value ;
rand_st->seed2=seed2%rand_st->max_value;
}
/*
Generate random number.
SYNOPSIS
my_rnd()
rand_st INOUT Structure used for number generation
RETURN VALUE
generated pseudo random number
*/
double my_rnd(struct my_rnd_struct *rand_st)
{
rand_st->seed1=(rand_st->seed1*3+rand_st->seed2) % rand_st->max_value;
rand_st->seed2=(rand_st->seed1+rand_st->seed2+33) % rand_st->max_value;
return (((double) rand_st->seed1)/rand_st->max_value_dbl);
}
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