yielder revamp, separate generators without having to return

master
Daniel Kolesa 2017-03-11 02:12:43 +01:00
parent b86df5c016
commit 935e1bc337
2 changed files with 269 additions and 98 deletions

View File

@ -4,12 +4,10 @@
using namespace ostd;
int main() {
coroutine<int()> g = [](auto yield) {
yield(5);
yield(10);
yield(15);
yield(20);
return 25;
generator<int> g = [](auto yield) -> void {
for (int i: range(5, 26, 5)) {
yield(i);
}
};
writeln("generator test");

View File

@ -26,9 +26,6 @@ struct coroutine_error: std::runtime_error {
template<typename T>
struct coroutine;
template<typename T>
struct coroutine_range;
namespace detail {
/* like reference_wrapper but for any value */
template<typename T>
@ -114,45 +111,42 @@ namespace detail {
using yield_type = std::pair<A, B>;
};
template<>
struct coro_types<> {
using yield_type = void;
};
template<typename ...A>
using coro_args = typename coro_types<A...>::yield_type;
template<typename ...A, size_t ...I>
inline coro_args<A...> yield_ret(
std::tuple<arg_wrapper<A>...> &args, std::index_sequence<I...>
) {
if constexpr(sizeof...(A) == 1) {
return std::forward<A...>(std::get<0>(args));
} else if constexpr(sizeof...(A) == 2) {
return std::make_pair(std::forward<A>(std::get<I>(args))...);
} else {
return std::move(args);
}
}
template<typename R, typename ...A>
struct coro_yielder;
/* default case, yield returns args and takes a value */
template<typename R, typename ...A>
struct coro_base: coroutine_context {
protected:
struct yielder {
yielder(coro_base<R, A...> &coro): p_coro(coro) {}
friend struct coro_yielder<R, A...>;
coro_args<A...> operator()(R &&ret) {
p_coro.p_result = std::forward<R>(ret);
p_coro.yield_jump();
return yield_ret(
p_coro.p_args, std::make_index_sequence<sizeof...(A)>{}
);
template<size_t ...I>
coro_args<A...> get_args(std::index_sequence<I...>) {
if constexpr(sizeof...(A) == 0) {
return;
} else if constexpr(sizeof...(A) == 1) {
return std::forward<A...>(std::get<0>(p_args));
} else if constexpr(sizeof...(A) == 2) {
return std::make_pair(std::forward<A>(std::get<I>(p_args))...);
} else {
return std::move(p_args);
}
private:
coro_base<R, A...> &p_coro;
};
}
template<typename F, size_t ...I>
void call_helper(F &func, std::index_sequence<I...>) {
p_result = std::forward<R>(
func(yielder{*this}, std::forward<A>(std::get<I>(p_args))...)
);
template<typename Y, typename F, size_t ...I>
void call_helper(Y &&yielder, F &func, std::index_sequence<I...>) {
p_result = std::forward<R>(func(
std::forward<Y>(yielder),
std::forward<A>(std::get<I>(p_args))...
));
}
R call(A ...args) {
@ -175,23 +169,15 @@ namespace detail {
/* yield takes a value but doesn't return any args */
template<typename R>
struct coro_base<R>: coroutine_context {
coroutine_range<R> iter();
protected:
struct yielder {
yielder(coro_base<R> &coro): p_coro(coro) {}
friend struct coro_yielder<R>;
void operator()(R &&ret) {
p_coro.p_result = std::forward<R>(ret);
p_coro.yield_jump();
}
private:
coro_base<R> &p_coro;
};
template<size_t ...I>
void get_args(std::index_sequence<I...>) {}
template<typename F, size_t ...I>
void call_helper(F &func, std::index_sequence<I...>) {
p_result = std::forward<R>(func(yielder{*this}));
template<typename Y, typename F, size_t ...I>
void call_helper(Y &&yielder, F &func, std::index_sequence<I...>) {
p_result = std::forward<R>(func(std::forward<Y>(yielder)));
}
R call() {
@ -212,22 +198,27 @@ namespace detail {
template<typename ...A>
struct coro_base<void, A...>: coroutine_context {
protected:
struct yielder {
yielder(coro_base<void, A...> &coro): p_coro(coro) {}
friend struct coro_yielder<void, A...>;
coro_args<A...> operator()() {
p_coro.yield_jump();
return yield_ret(
p_coro.p_args, std::make_index_sequence<sizeof...(A)>{}
);
template<size_t ...I>
coro_args<A...> get_args(std::index_sequence<I...>) {
if constexpr(sizeof...(A) == 0) {
return;
} else if constexpr(sizeof...(A) == 1) {
return std::forward<A...>(std::get<0>(p_args));
} else if constexpr(sizeof...(A) == 2) {
return std::make_pair(std::forward<A>(std::get<I>(p_args))...);
} else {
return std::move(p_args);
}
private:
coro_base<void, A...> &p_coro;
};
}
template<typename F, size_t ...I>
void call_helper(F &func, std::index_sequence<I...>) {
func(yielder{*this}, std::forward<A>(std::get<I>(p_args))...);
template<typename Y, typename F, size_t ...I>
void call_helper(Y &&yielder, F &func, std::index_sequence<I...>) {
func(
std::forward<Y>(yielder),
std::forward<A>(std::get<I>(p_args))...
);
}
void call(A ...args) {
@ -248,19 +239,14 @@ namespace detail {
template<>
struct coro_base<void>: coroutine_context {
protected:
struct yielder {
yielder(coro_base<void> &coro): p_coro(coro) {}
friend struct coro_yielder<void>;
void operator()() {
p_coro.yield_jump();
}
private:
coro_base<void> &p_coro;
};
template<size_t ...I>
void get_args(std::index_sequence<I...>) {}
template<typename F, size_t ...I>
void call_helper(F &func, std::index_sequence<I...>) {
func(yielder{*this});
template<typename Y, typename F, size_t ...I>
void call_helper(Y &&yielder, F &func, std::index_sequence<I...>) {
func(std::forward<Y>(yielder));
}
void call() {
@ -271,6 +257,67 @@ namespace detail {
coroutine_context::swap(other);
}
};
template<typename R, typename ...A>
struct coro_yielder {
coro_yielder(coro_base<R, A...> &coro): p_coro(coro) {}
coro_args<A...> operator()(R &&ret) {
p_coro.p_result = std::forward<R>(ret);
p_coro.yield_jump();
return p_coro.get_args(std::make_index_sequence<sizeof...(A)>{});
}
coro_args<A...> operator()(R const &ret) {
p_coro.p_result = ret;
p_coro.yield_jump();
return p_coro.get_args(std::make_index_sequence<sizeof...(A)>{});
}
private:
coro_base<R, A...> &p_coro;
};
template<typename R, typename ...A>
struct coro_yielder<R &, A...> {
coro_yielder(coro_base<R &, A...> &coro): p_coro(coro) {}
coro_args<A...> operator()(R &ret) {
p_coro.p_result = ret;
p_coro.yield_jump();
return p_coro.get_args(std::make_index_sequence<sizeof...(A)>{});
}
private:
coro_base<R &, A...> &p_coro;
};
template<typename R, typename ...A>
struct coro_yielder<R &&, A...> {
coro_yielder(coro_base<R &&, A...> &coro): p_coro(coro) {}
coro_args<A...> operator()(R &&ret) {
p_coro.p_result = std::forward<R>(ret);
p_coro.yield_jump();
return p_coro.get_args(std::make_index_sequence<sizeof...(A)>{});
}
private:
coro_base<R &&, A...> &p_coro;
};
template<typename ...A>
struct coro_yielder<void, A...> {
coro_yielder(coro_base<void, A...> &coro): p_coro(coro) {}
coro_args<A...> operator()() {
p_coro.yield_jump();
return p_coro.get_args(std::make_index_sequence<sizeof...(A)>{});
}
private:
coro_base<void, A...> &p_coro;
};
} /* namespace detail */
template<typename R, typename ...A>
@ -279,7 +326,7 @@ private:
using base_t = detail::coro_base<R, A...>;
public:
using yield_type = typename detail::coro_base<R, A...>::yielder;
using yield_type = detail::coro_yielder<R, A...>;
/* we have no way to assign a function anyway... */
coroutine() = delete;
@ -349,7 +396,9 @@ private:
goto release;
}
try {
self.call_helper(self.p_func, std::index_sequence_for<A...>{});
self.call_helper(
yield_type{self}, self.p_func, std::index_sequence_for<A...>{}
);
} catch (detail::coroutine_context::forced_unwind v) {
/* forced_unwind is unique */
self.p_orig = v.ctx;
@ -371,50 +420,174 @@ inline void swap(coroutine<R(A...)> &a, coroutine<R(A...)> &b) {
a.swap(b);
}
template<typename T> struct generator_range;
template<typename T>
struct coroutine_range: input_range<coroutine_range<T>> {
struct generator: detail::coroutine_context {
private:
struct yielder {
yielder(generator<T> &g): p_gen(g) {}
void operator()(T &&ret) {
p_gen.p_result = &ret;
p_gen.yield_jump();
}
void operator()(T &ret) {
p_gen.p_result = &ret;
p_gen.yield_jump();
}
private:
generator<T> &p_gen;
};
public:
using range = generator_range<T>;
using yield_type = yielder;
generator() = delete;
template<typename F, typename SA = default_stack>
generator(F func, SA sa = SA{0}): p_func(std::move(func)) {
/* that way there is no context creation/stack allocation */
if (!p_func) {
return;
}
this->make_context(sa, &context_call<SA>);
}
generator(generator const &) = delete;
generator(generator &&c):
p_func(std::move(c.p_func)), p_result(c.p_result)
{
c.p_func = nullptr;
c.p_result = nullptr;
}
generator &operator=(generator const &) = delete;
generator &operator=(generator &&c) {
p_func = std::move(c.p_func);
p_result = c.p_result;
c.p_func = nullptr;
c.p_result = nullptr;
}
~generator() {
if (this->p_state == detail::coroutine_context::state::TERM) {
return;
}
this->unwind();
}
explicit operator bool() const {
return (this->p_state != detail::coroutine_context::state::TERM);
}
void resume() {
if (this->p_state == detail::coroutine_context::state::TERM) {
throw coroutine_error{"dead generator"};
}
detail::coroutine_context::call();
}
T &value() {
if (!p_result) {
throw coroutine_error{"no value"};
}
return *p_result;
}
T const &value() const {
if (!p_result) {
throw coroutine_error{"no value"};
}
return *p_result;
}
bool empty() const {
return (!p_result || this->p_state == detail::coroutine_context::state::TERM);
}
generator_range<T> iter();
void swap(generator &other) {
using std::swap;
swap(p_func, other.p_func);
swap(p_result, other.p_result);
detail::coroutine_context::swap(other);
}
private:
/* the main entry point of the generator */
template<typename SA>
static void context_call(detail::transfer_t t) {
auto &self = *(static_cast<generator *>(t.data));
self.p_orig = t.ctx;
if (self.p_state == detail::coroutine_context::state::INIT) {
goto release;
}
try {
self.p_func(yield_type{self});
} catch (detail::coroutine_context::forced_unwind v) {
self.p_orig = v.ctx;
} catch (...) {
self.p_except = std::current_exception();
}
release:
self.p_state = detail::coroutine_context::state::TERM;
self.p_result = nullptr;
self.template finish<SA>();
}
std::function<void(yield_type)> p_func;
/* we can use a pointer because even stack values are alive
* as long as the coroutine is alive (and it is on every yield)
*/
T *p_result = nullptr;
};
template<typename T>
inline void swap(generator<T> &a, generator<T> &b) {
a.swap(b);
}
template<typename T>
struct generator_range: input_range<generator_range<T>> {
using range_category = input_range_tag;
using value_type = T;
using reference = T &;
using size_type = size_t;
using difference_type = stream_off_t;
coroutine_range() = delete;
coroutine_range(coroutine<T()> &c): p_coro(&c) {
generator_range() = delete;
generator_range(generator<T> &g): p_gen(&g) {
pop_front();
}
coroutine_range(coroutine_range const &r):
p_coro(r.p_coro), p_item(r.p_item) {}
generator_range(generator_range const &r): p_gen(r.p_gen) {}
bool empty() const {
return !p_item;
return p_gen->empty();
}
void pop_front() {
if (*p_coro) {
p_item = (*p_coro)();
} else {
p_item = std::nullopt;
}
p_gen->resume();
}
reference front() const {
return p_item.value();
return p_gen->value();
}
bool equals_front(coroutine_range const &g) const {
return p_coro == g.p_coro;
bool equals_front(generator_range const &g) const {
return p_gen == g.p_gen;
}
private:
coroutine<T()> *p_coro;
mutable std::optional<T> p_item;
generator<T> *p_gen;
};
namespace detail {
template<typename R>
coroutine_range<R> coro_base<R>::iter() {
return coroutine_range<R>{static_cast<coroutine<R()> &>(*this)};
}
template<typename T>
generator_range<T> generator<T>::iter() {
return generator_range<T>{*this};
}
} /* namespace ostd */