diff options
Diffstat (limited to 'mysys/my_rnd.c')
| -rw-r--r-- | mysys/my_rnd.c | 48 |
1 files changed, 45 insertions, 3 deletions
diff --git a/mysys/my_rnd.c b/mysys/my_rnd.c index 178bcd9c539..ad7bda0b42b 100644 --- a/mysys/my_rnd.c +++ b/mysys/my_rnd.c @@ -14,6 +14,7 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include "mysys_priv.h" +#include <my_rnd.h> #include <m_string.h> /* @@ -45,11 +46,52 @@ void my_rnd_init(struct my_rnd_struct *rand_st, ulong seed1, ulong seed2) RETURN VALUE generated pseudo random number + + NOTE: + This is codes so that it can be called by two threads at the same time + with minimum impact. + (As the number is supposed to be random, it doesn't matter much if + rand->seed1 or rand->seed2 are updated with slightly wrong numbers or + if two threads gets the same 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); + unsigned long seed1; + seed1= (rand_st->seed1*3+rand_st->seed2) % rand_st->max_value; + rand_st->seed2=(seed1+rand_st->seed2+33) % rand_st->max_value; + rand_st->seed1= seed1; + return (((double) 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); } |