catch2/generators/catch_generators_random.hpp

0001
0002 //              Copyright Catch2 Authors
0003 // Distributed under the Boost Software License, Version 1.0.
0004 //   (See accompanying file LICENSE.txt or copy at
0005 //        https://www.boost.org/LICENSE_1_0.txt)
0006
0007 // SPDX-License-Identifier: BSL-1.0
0008 #ifndef CATCH_GENERATORS_RANDOM_HPP_INCLUDED
0009 #define CATCH_GENERATORS_RANDOM_HPP_INCLUDED
0010
0011 #include <catch2/internal/catch_context.hpp>
0012 #include <catch2/generators/catch_generators.hpp>
0013 #include <catch2/internal/catch_random_number_generator.hpp>
0014
0015 #include <random>
0016
0017 namespace Catch {
0018 namespace Generators {
0019 namespace Detail {
0020     // Returns a suitable seed for a random floating generator based off
0021     // the primary internal rng. It does so by taking current value from
0022     // the rng and returning it as the seed.
0023     std::uint32_t getSeed();
0024 }
0025
0026 template <typename Float>
0027 class RandomFloatingGenerator final : public IGenerator<Float> {
0028     Catch::SimplePcg32 m_rng;
0029     std::uniform_real_distribution<Float> m_dist;
0030     Float m_current_number;
0031 public:
0032     RandomFloatingGenerator( Float a, Float b, std::uint32_t seed ):
0033         m_rng(seed),
0034         m_dist(a, b) {
0035         static_cast<void>(next());
0036     }
0037
0038     Float const& get() const override {
0039         return m_current_number;
0040     }
0041     bool next() override {
0042         m_current_number = m_dist(m_rng);
0043         return true;
0044     }
0045 };
0046
0047 template <typename Integer>
0048 class RandomIntegerGenerator final : public IGenerator<Integer> {
0049     Catch::SimplePcg32 m_rng;
0050     std::uniform_int_distribution<Integer> m_dist;
0051     Integer m_current_number;
0052 public:
0053     RandomIntegerGenerator( Integer a, Integer b, std::uint32_t seed ):
0054         m_rng(seed),
0055         m_dist(a, b) {
0056         static_cast<void>(next());
0057     }
0058
0059     Integer const& get() const override {
0060         return m_current_number;
0061     }
0062     bool next() override {
0063         m_current_number = m_dist(m_rng);
0064         return true;
0065     }
0066 };
0067
0068 template <typename T>
0069 std::enable_if_t<std::is_integral<T>::value, GeneratorWrapper<T>>
0070 random(T a, T b) {
0071     static_assert(
0072         !std::is_same<T, char>::value &&
0073         !std::is_same<T, int8_t>::value &&
0074         !std::is_same<T, uint8_t>::value &&
0075         !std::is_same<T, signed char>::value &&
0076         !std::is_same<T, unsigned char>::value &&
0077         !std::is_same<T, bool>::value,
0078         "The requested type is not supported by the underlying random distributions from std" );
0079     return GeneratorWrapper<T>(
0080         Catch::Detail::make_unique<RandomIntegerGenerator<T>>(a, b, Detail::getSeed())
0081     );
0082 }
0083
0084 template <typename T>
0085 std::enable_if_t<std::is_floating_point<T>::value,
0086 GeneratorWrapper<T>>
0087 random(T a, T b) {
0088     return GeneratorWrapper<T>(
0089         Catch::Detail::make_unique<RandomFloatingGenerator<T>>(a, b, Detail::getSeed())
0090     );
0091 }
0092
0093
0094 } // namespace Generators
0095 } // namespace Catch
0096
0097
0098 #endif // CATCH_GENERATORS_RANDOM_HPP_INCLUDED