Introduce random number (Integral and Float) generators

include/internal/catch_generators_specific.hpp

@@ -0,0 +1,88 @@
+/*
+ *  Created by Martin on 15/6/2018.
+ *
+ *  Distributed under the Boost Software License, Version 1.0. (See accompanying
+ *  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+ */
+#ifndef TWOBLUECUBES_CATCH_GENERATORS_SPECIFIC_HPP_INCLUDED
+#define TWOBLUECUBES_CATCH_GENERATORS_SPECIFIC_HPP_INCLUDED
+
+#include "catch_context.h"
+#include "catch_generators.hpp"
+#include "catch_interfaces_config.h"
+
+#include <random>
+
+namespace Catch {
+namespace Generators {
+
+template <typename Float>
+class RandomFloatingGenerator final : public IGenerator<Float> {
+    // FIXME: What is the right seed?
+    std::minstd_rand m_rand;
+    std::uniform_real_distribution<Float> m_dist;
+    Float m_current_number;
+public:
+
+    RandomFloatingGenerator(Float a, Float b):
+        m_rand(getCurrentContext().getConfig()->rngSeed()),
+        m_dist(a, b) {
+        static_cast<void>(next());
+    }
+
+    Float const& get() const override {
+        return m_current_number;
+    }
+    bool next() override {
+        m_current_number = m_dist(m_rand);
+        return true;
+    }
+};
+
+template <typename Integer>
+class RandomIntegerGenerator final : public IGenerator<Integer> {
+    std::minstd_rand m_rand;
+    std::uniform_int_distribution<Integer> m_dist;
+    Integer m_current_number;
+public:
+
+    RandomIntegerGenerator(Integer a, Integer b):
+        m_rand(getCurrentContext().getConfig()->rngSeed()),
+        m_dist(a, b) {
+        static_cast<void>(next());
+    }
+
+    Integer const& get() const override {
+        return m_current_number;
+    }
+    bool next() override {
+        m_current_number = m_dist(m_rand);
+        return true;
+    }
+};
+
+// TODO: Ideally this would be also constrained against the various char types,
+//       but I don't expect users to run into that in practice.
+template <typename T>
+typename std::enable_if<std::is_integral<T>::value && !std::is_same<T, bool>::value,
+GeneratorWrapper<T>>::type
+random(T a, T b) {
+    return GeneratorWrapper<T>(
+        pf::make_unique<RandomIntegerGenerator<T>>(a, b)
+    );
+}
+
+template <typename T>
+typename std::enable_if<std::is_floating_point<T>::value,
+GeneratorWrapper<T>>::type
+random(T a, T b) {
+    return GeneratorWrapper<T>(
+        pf::make_unique<RandomFloatingGenerator<T>>(a, b)
+    );
+}
+
+} // namespace Generators
+} // namespace Catch
+
+
+#endif // TWOBLUECUBES_CATCH_GENERATORS_SPECIFIC_HPP_INCLUDED