/*
   Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved.

   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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA */

#include <my_global.h>
#include <my_rnd.h>
#include <m_string.h>

#if defined(HAVE_YASSL)
#if defined(YASSL_PREFIX)
#define RAND_bytes yaRAND_bytes
#endif /* YASSL_PREFIX */

#include <openssl/ssl.h>

#elif defined(HAVE_OPENSSL)
#include <openssl/rand.h>
#endif /* HAVE_YASSL */


/*
  A wrapper to use OpenSSL/yaSSL PRNGs.
*/

extern "C" {

/*
  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.

  @param rand_st [INOUT] Structure used for number generation.

  @retval                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);
}

/**
  Generate a random number using the OpenSSL/yaSSL supplied
  random number generator if available.

  @param rand_st [INOUT] Structure used for number generation
                         only if none of the SSL libraries are
                         available.

  @retval                Generated random number.
*/

double my_rnd_ssl(struct my_rnd_struct *rand_st)
{

#if defined(HAVE_YASSL) || defined(HAVE_OPENSSL)
  int rc;
  unsigned int res;

#if defined(HAVE_YASSL)
  rc= yaSSL::RAND_bytes((unsigned char *) &res, sizeof (unsigned int));
#else
  rc= RAND_bytes((unsigned char *) &res, sizeof (unsigned int));
#endif /* HAVE_YASSL */
  if (rc)
    return (double)res / (double)UINT_MAX;

#endif /* defined(HAVE_YASSL) || defined(HAVE_OPENSSL) */
  return my_rnd(rand_st);
}

}