Avoid overflow. Fixes #8351.

boostorg · Mar 13, 2014 · c0a694e · jzmaddock · Feb 28, 2015 · swatanabe
1 parent dbb7b3c
commit c0a694e
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diff --git a/include/boost/random/uniform_real_distribution.hpp b/include/boost/random/uniform_real_distribution.hpp
@@ -65,6 +65,8 @@ T generate_uniform_real(
 template<class Engine, class T>
 inline T generate_uniform_real(Engine& eng, T min_value, T max_value)
 {
+    if(max_value / 2 - min_value / 2 > (std::numeric_limits<T>::max)() / 2)
+        return 2 * generate_uniform_real(eng, min_value / 2, max_value / 2);
     typedef typename Engine::result_type base_result;
     return generate_uniform_real(eng, min_value, max_value,
         boost::is_integral<base_result>());

diff --git a/test/test_uniform_real_distribution.cpp b/test/test_uniform_real_distribution.cpp
@@ -36,3 +36,13 @@
 #define BOOST_RANDOM_TEST2_MAX 1.0
 
 #include "test_distribution.ipp"
+
+BOOST_AUTO_TEST_CASE(test_dbl_min_max) {
+    boost::random::minstd_rand rng;
+    double min = -(std::numeric_limits<double>::max)();
+    double max = (std::numeric_limits<double>::max)();
+    boost::random::uniform_real_distribution<double> dist(min, max);
+    double val = dist(rng);
+    BOOST_CHECK_GE(val, min);
+    BOOST_CHECK_LE(val, max);
+}