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fix generated view

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This commit is contained in:
janis 2022-07-13 01:40:17 +01:00
parent 8b0ef87f17
commit d6608aa6b4
2 changed files with 42 additions and 15 deletions
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32
include/ranges/generated.hpp
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@ -17,11 +17,30 @@ template <std::invocable F> struct generated_iterator {
using difference_type = std::ptrdiff_t;
value_type value{};
F generator{};
F generator;
// TODO: make 1 constructor that generates a value, move/copy value in all
// other constructors
generated_iterator() = default;
generated_iterator(F gen) : generator(gen), value(gen()) {}
generated_iterator(F &&gen) : generator(std::move(gen)), value(gen()) {}
explicit generated_iterator(F &&gen)
: generator(std::move(gen)), value(gen()) {}
generated_iterator(const generated_iterator &other)
: generator(other.generator), value(other.value) {}
generated_iterator(generated_iterator &&other)
: generator(std::move(other.generator)), value(std::move(other.value)) {}
auto operator=(const generated_iterator &other) -> generated_iterator & {
generator = other.generator;
value = other.value;
return *this;
}
auto operator=(generated_iterator &&other) -> generated_iterator & {
generator = std::move(other.generator);
value = std::move(other.value);
return *this;
}
auto generate_new_value() -> void { value = generator(); }
@ -47,13 +66,14 @@ template <std::invocable F> struct generated_iterator {
template <std::invocable F>
class generated_view : rg::view_interface<generated_view<F>> {
F generator = {};
detail::generated_iterator<F> iter_{};
public:
constexpr generated_view() = default;
constexpr generated_view(F generator) : generator(std::move(generator)) {}
constexpr generated_view(F generator)
: iter_(detail::generated_iterator(std::move(generator))) {}
constexpr auto begin() const { return detail::generated_iterator(generator); }
constexpr auto begin() const { return iter_; }
constexpr auto end() const { return std::unreachable_sentinel; }
};

25
src/main.cc
View file

@ -61,16 +61,23 @@ auto test_enumerate_view() {
}
auto test_generated_view() {
const auto random =
util::views::from([] {
return "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXY"
[std::rand() %
std::strlen(
"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXY")];
}) |
std::views::take(10) | util::views::collect<std::string>;
{
const auto view = util::views::from([] { return 's'; });
auto it = std::ranges::begin(view);
util::println("random string: {}", random);
util::assert_eq(*it, *it);
util::assert_eq(*it, 's');
}
{
auto count = 0;
const auto view = util::views::from([&] { return count++; });
auto it = std::ranges::begin(view);
util::assert_eq(*it, *it);
util::assert_ne(*it++, *it++);
util::assert_ne(*it + 1, *++it);
}
}
auto test_collect() {