238 lines
8.3 KiB
C++
238 lines
8.3 KiB
C++
/*
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* Created by Martin on 23/2/2019.
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*
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* Distributed under the Boost Software License, Version 1.0. (See accompanying
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* file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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*/
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#ifndef TWOBLUECUBES_CATCH_GENERATORS_GENERIC_HPP_INCLUDED
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#define TWOBLUECUBES_CATCH_GENERATORS_GENERIC_HPP_INCLUDED
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#include "catch_generators.hpp"
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#include "catch_meta.hpp"
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namespace Catch {
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namespace Generators {
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template <typename T>
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class TakeGenerator : public IGenerator<T> {
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GeneratorWrapper<T> m_generator;
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size_t m_returned = 0;
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size_t m_target;
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public:
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TakeGenerator(size_t target, GeneratorWrapper<T>&& generator):
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m_generator(std::move(generator)),
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m_target(target)
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{
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assert(target != 0 && "Empty generators are not allowed");
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}
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T const& get() const override {
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return m_generator.get();
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}
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bool next() override {
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++m_returned;
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if (m_returned >= m_target) {
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return false;
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}
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const auto success = m_generator.next();
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// If the underlying generator does not contain enough values
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// then we cut short as well
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if (!success) {
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m_returned = m_target;
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}
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return success;
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}
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};
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template <typename T>
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GeneratorWrapper<T> take(size_t target, GeneratorWrapper<T>&& generator) {
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return GeneratorWrapper<T>(pf::make_unique<TakeGenerator<T>>(target, std::move(generator)));
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}
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template <typename T, typename Predicate>
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class FilterGenerator : public IGenerator<T> {
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GeneratorWrapper<T> m_generator;
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Predicate m_predicate;
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public:
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template <typename P = Predicate>
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FilterGenerator(P&& pred, GeneratorWrapper<T>&& generator):
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m_generator(std::move(generator)),
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m_predicate(std::forward<P>(pred))
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{
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if (!m_predicate(m_generator.get())) {
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// It might happen that there are no values that pass the
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// filter. In that case we throw an exception.
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auto has_initial_value = next();
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if (!has_initial_value) {
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Catch::throw_exception(GeneratorException("No valid value found in filtered generator"));
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}
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}
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}
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T const& get() const override {
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return m_generator.get();
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}
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bool next() override {
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bool success = m_generator.next();
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if (!success) {
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return false;
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}
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while (!m_predicate(m_generator.get()) && (success = m_generator.next()) == true);
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return success;
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}
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};
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template <typename T, typename Predicate>
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GeneratorWrapper<T> filter(Predicate&& pred, GeneratorWrapper<T>&& generator) {
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return GeneratorWrapper<T>(std::unique_ptr<IGenerator<T>>(pf::make_unique<FilterGenerator<T, Predicate>>(std::forward<Predicate>(pred), std::move(generator))));
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}
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template <typename T>
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class RepeatGenerator : public IGenerator<T> {
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static_assert(!std::is_same<T, bool>::value,
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"RepeatGenerator currently does not support bools"
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"because of std::vector<bool> specialization");
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GeneratorWrapper<T> m_generator;
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mutable std::vector<T> m_returned;
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size_t m_target_repeats;
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size_t m_current_repeat = 0;
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size_t m_repeat_index = 0;
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public:
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RepeatGenerator(size_t repeats, GeneratorWrapper<T>&& generator):
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m_generator(std::move(generator)),
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m_target_repeats(repeats)
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{
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assert(m_target_repeats > 0 && "Repeat generator must repeat at least once");
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}
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T const& get() const override {
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if (m_current_repeat == 0) {
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m_returned.push_back(m_generator.get());
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return m_returned.back();
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}
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return m_returned[m_repeat_index];
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}
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bool next() override {
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// There are 2 basic cases:
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// 1) We are still reading the generator
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// 2) We are reading our own cache
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// In the first case, we need to poke the underlying generator.
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// If it happily moves, we are left in that state, otherwise it is time to start reading from our cache
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if (m_current_repeat == 0) {
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const auto success = m_generator.next();
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if (!success) {
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++m_current_repeat;
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}
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return m_current_repeat < m_target_repeats;
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}
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// In the second case, we need to move indices forward and check that we haven't run up against the end
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++m_repeat_index;
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if (m_repeat_index == m_returned.size()) {
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m_repeat_index = 0;
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++m_current_repeat;
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}
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return m_current_repeat < m_target_repeats;
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}
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};
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template <typename T>
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GeneratorWrapper<T> repeat(size_t repeats, GeneratorWrapper<T>&& generator) {
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return GeneratorWrapper<T>(pf::make_unique<RepeatGenerator<T>>(repeats, std::move(generator)));
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}
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template <typename T, typename U, typename Func>
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class MapGenerator : public IGenerator<T> {
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// TBD: provide static assert for mapping function, for friendly error message
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GeneratorWrapper<U> m_generator;
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Func m_function;
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// To avoid returning dangling reference, we have to save the values
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T m_cache;
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public:
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template <typename F2 = Func>
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MapGenerator(F2&& function, GeneratorWrapper<U>&& generator) :
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m_generator(std::move(generator)),
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m_function(std::forward<F2>(function)),
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m_cache(m_function(m_generator.get()))
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{}
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T const& get() const override {
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return m_cache;
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}
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bool next() override {
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const auto success = m_generator.next();
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if (success) {
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m_cache = m_function(m_generator.get());
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}
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return success;
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}
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};
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template <typename Func, typename U, typename T = FunctionReturnType<Func, U>>
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GeneratorWrapper<T> map(Func&& function, GeneratorWrapper<U>&& generator) {
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return GeneratorWrapper<T>(
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pf::make_unique<MapGenerator<T, U, Func>>(std::forward<Func>(function), std::move(generator))
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);
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}
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template <typename T, typename U, typename Func>
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GeneratorWrapper<T> map(Func&& function, GeneratorWrapper<U>&& generator) {
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return GeneratorWrapper<T>(
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pf::make_unique<MapGenerator<T, U, Func>>(std::forward<Func>(function), std::move(generator))
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);
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}
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template <typename T>
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class ChunkGenerator final : public IGenerator<std::vector<T>> {
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std::vector<T> m_chunk;
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size_t m_chunk_size;
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GeneratorWrapper<T> m_generator;
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bool m_used_up = false;
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public:
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ChunkGenerator(size_t size, GeneratorWrapper<T> generator) :
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m_chunk_size(size), m_generator(std::move(generator))
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{
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m_chunk.reserve(m_chunk_size);
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if (m_chunk_size != 0) {
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m_chunk.push_back(m_generator.get());
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for (size_t i = 1; i < m_chunk_size; ++i) {
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if (!m_generator.next()) {
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Catch::throw_exception(GeneratorException("Not enough values to initialize the first chunk"));
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}
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m_chunk.push_back(m_generator.get());
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}
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}
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}
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std::vector<T> const& get() const override {
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return m_chunk;
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}
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bool next() override {
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m_chunk.clear();
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for (size_t idx = 0; idx < m_chunk_size; ++idx) {
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if (!m_generator.next()) {
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return false;
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}
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m_chunk.push_back(m_generator.get());
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}
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return true;
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}
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};
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template <typename T>
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GeneratorWrapper<std::vector<T>> chunk(size_t size, GeneratorWrapper<T>&& generator) {
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return GeneratorWrapper<std::vector<T>>(
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pf::make_unique<ChunkGenerator<T>>(size, std::move(generator))
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);
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}
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} // namespace Generators
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} // namespace Catch
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#endif // TWOBLUECUBES_CATCH_GENERATORS_GENERIC_HPP_INCLUDED
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