| 4142 | |
| 4143 | template <typename T> |
| 4144 | class RepeatGenerator : public IGenerator<T> { |
| 4145 | static_assert(!std::is_same<T, bool>::value, |
| 4146 | "RepeatGenerator currently does not support bools" |
| 4147 | "because of std::vector<bool> specialization"); |
| 4148 | GeneratorWrapper<T> m_generator; |
| 4149 | mutable std::vector<T> m_returned; |
| 4150 | size_t m_target_repeats; |
| 4151 | size_t m_current_repeat = 0; |
| 4152 | size_t m_repeat_index = 0; |
| 4153 | public: |
| 4154 | RepeatGenerator(size_t repeats, GeneratorWrapper<T>&& generator): |
| 4155 | m_generator(std::move(generator)), |
| 4156 | m_target_repeats(repeats) |
| 4157 | { |
| 4158 | assert(m_target_repeats > 0 && "Repeat generator must repeat at least once"); |
| 4159 | } |
| 4160 | |
| 4161 | T const& get() const override { |
| 4162 | if (m_current_repeat == 0) { |
| 4163 | m_returned.push_back(m_generator.get()); |
| 4164 | return m_returned.back(); |
| 4165 | } |
| 4166 | return m_returned[m_repeat_index]; |
| 4167 | } |
| 4168 | |
| 4169 | bool next() override { |
| 4170 | // There are 2 basic cases: |
| 4171 | // 1) We are still reading the generator |
| 4172 | // 2) We are reading our own cache |
| 4173 | |
| 4174 | // In the first case, we need to poke the underlying generator. |
| 4175 | // If it happily moves, we are left in that state, otherwise it is time to start reading from our cache |
| 4176 | if (m_current_repeat == 0) { |
| 4177 | const auto success = m_generator.next(); |
| 4178 | if (!success) { |
| 4179 | ++m_current_repeat; |
| 4180 | } |
| 4181 | return m_current_repeat < m_target_repeats; |
| 4182 | } |
| 4183 | |
| 4184 | // In the second case, we need to move indices forward and check that we haven't run up against the end |
| 4185 | ++m_repeat_index; |
| 4186 | if (m_repeat_index == m_returned.size()) { |
| 4187 | m_repeat_index = 0; |
| 4188 | ++m_current_repeat; |
| 4189 | } |
| 4190 | return m_current_repeat < m_target_repeats; |
| 4191 | } |
| 4192 | }; |
| 4193 | |
| 4194 | template <typename T> |
| 4195 | GeneratorWrapper<T> repeat(size_t repeats, GeneratorWrapper<T>&& generator) { |