diff --git a/test/random_shuffle.hpp b/test/random_shuffle.hpp index 5041d96..907d195 100644 --- a/test/random_shuffle.hpp +++ b/test/random_shuffle.hpp @@ -6,13 +6,27 @@ #include #include +inline unsigned long long rand_15_bit() +{ + //Many rand implementation only use 15 bits + //so make sure we have only 15 bits + return (unsigned long long)((std::rand()) & 0x7fffu); +} + +inline unsigned long long ullrand() +{ + return (rand_15_bit() << 54u) ^ (rand_15_bit() << 39u) + ^ (rand_15_bit() << 26u) ^ (rand_15_bit() << 13u) + ^ rand_15_bit(); +} + template< class RandomIt > void random_shuffle( RandomIt first, RandomIt last ) { typedef typename boost::movelib::iterator_traits::difference_type difference_type; difference_type n = last - first; for (difference_type i = n-1; i > 0; --i) { - difference_type j = std::rand() % (i+1); + difference_type j = ullrand() % (i+1); if(j != i) { boost::adl_move_swap(first[i], first[j]); }