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#pragma once
#include "name-of.hpp"
#include "accessor.hpp"
#include "constraints.hpp"
#include "util.hpp"
#include "concepts.hpp"
#include "compat/defs.hpp"
#include <cstddef>
#include <concepts>
#include <type_traits>
#include <limits>
#include <utility>
#include <tuple>
#include <array>
#include <compat/function2.hpp>
#include <Corrade/Containers/StringView.h>
namespace floormat::entities::detail {
template<typename F, typename Tuple, std::size_t N>
requires std::invocable<F, decltype(std::get<N>(std::declval<Tuple>()))>
constexpr CORRADE_ALWAYS_INLINE void visit_tuple(F&& fun, Tuple&& tuple)
{
using Size = std::tuple_size<std::remove_cvref_t<Tuple>>;
static_assert(N < Size());
fun(std::get<N>(tuple));
if constexpr(N+1 < Size())
visit_tuple<F, Tuple, N+1>(std::forward<F>(fun), std::forward<Tuple>(tuple));
}
template<typename F, typename Tuple, std::size_t N>
requires std::is_invocable_r_v<bool, F, decltype(std::get<N>(std::declval<Tuple>()))>
constexpr CORRADE_ALWAYS_INLINE bool find_in_tuple(F&& fun, Tuple&& tuple)
{
using Size = std::tuple_size<std::remove_cvref_t<Tuple>>;
static_assert(N < Size());
if (fun(std::get<N>(tuple)))
return true;
if constexpr(N+1 < Size())
return find_in_tuple<F, Tuple, N+1>(std::forward<F>(fun), std::forward<Tuple>(tuple));
return false;
}
template<typename T> struct decay_tuple_;
template<typename... Ts> struct decay_tuple_<std::tuple<Ts...>> { using type = std::tuple<std::decay_t<Ts>...>; };
template<typename T> using decay_tuple = typename decay_tuple_<T>::type;
template<typename T> struct accessors_for_ { using type = decay_tuple<std::decay_t<decltype(T::accessors())>>; };
template<typename T> using accessors_for = typename accessors_for_<T>::type;
template<typename Obj, typename Type, typename Default, std::size_t I, typename... Fs> struct find_reader;
template<typename Obj, typename Type, typename Default, std::size_t I> struct find_reader<Obj, Type, Default, I> {
using type = Default;
static constexpr std::size_t index = I;
};
template<typename Obj, typename Type, typename Default, std::size_t I, typename F, typename... Fs>
struct find_reader<Obj, Type, Default, I, F, Fs...> {
using type = typename find_reader<Obj, Type, Default, I+1, Fs...>::type;
static constexpr std::size_t index = find_reader<Obj, Type, Default, I+1, Fs...>::index;
};
template<typename Obj, typename Type, typename Default, std::size_t I, typename F, typename... Fs>
requires FieldReader<F, Obj, Type>
struct find_reader<Obj, Type, Default, I, F, Fs...> { using type = F; static constexpr std::size_t index = I; };
} // namespace floormat::entities::detail
namespace floormat::entities {
template<typename... Ts> constexpr auto constantly(const auto& x) noexcept { return [x](const Ts&...) constexpr { return x; }; }
template<typename Obj, typename Type> struct entity_field_base {};
template<typename Obj, typename Type, FieldReader<Obj, Type> R, FieldWriter<Obj, Type> W, typename... Ts>
struct entity_field : entity_field_base<Obj, Type> {
private:
static constexpr auto default_predicate = constantly<Obj>(field_status::enabled);
static constexpr auto default_c_range = constantly<Obj>(constraints::range<Type>{});
static constexpr auto default_c_length = constantly<Obj>(constraints::length{std::size_t(-1)});
static constexpr auto default_c_group = constantly<Obj>(StringView{});
using default_predicate_t = std::decay_t<decltype(default_predicate)>;
using default_c_range_t = std::decay_t<decltype(default_c_range)>;
using default_c_length_t = std::decay_t<decltype(default_c_length)>;
using default_c_group_t = std::decay_t<decltype(default_c_group)>;
using c_predicate = detail::find_reader<Obj, field_status, default_predicate_t, 0, Ts...>;
using c_range = detail::find_reader<Obj, constraints::range<Type>, default_c_range_t, 0, Ts...>;
using c_length = detail::find_reader<Obj, constraints::length, default_c_length_t, 0, Ts...>;
using c_group = detail::find_reader<Obj, constraints::group, default_c_group_t, 0, Ts...>;
static constexpr std::size_t good_arguments =
unsigned(c_predicate::index != sizeof...(Ts)) +
unsigned(c_range::index != sizeof...(Ts)) +
unsigned(c_length::index != sizeof...(Ts)) +
unsigned(c_group::index != sizeof...(Ts));
static_assert(sizeof...(Ts) == good_arguments, "ignored arguments");
public:
using ObjectType = Obj;
using FieldType = Type;
using Reader = R;
using Writer = W;
using Predicate = typename c_predicate::type;
using Range = typename c_range::type;
using Length = typename c_length::type;
using Group = typename c_group::type;
StringView name;
[[no_unique_address]] R reader;
[[no_unique_address]] W writer;
[[no_unique_address]] Predicate predicate;
[[no_unique_address]] Range range;
[[no_unique_address]] Length length;
[[no_unique_address]] Group group;
fm_DECLARE_DEFAULT_MOVE_COPY_ASSIGNMENTS(entity_field);
static constexpr decltype(auto) read(const R& reader, const Obj& x) { return detail::read_field<Obj, Type, R>::read(x, reader); }
static constexpr void write(const W& writer, Obj& x, move_qualified<Type> v);
constexpr decltype(auto) read(const Obj& x) const { return read(reader, x); }
constexpr void write(Obj& x, move_qualified<Type> value) const { write(writer, x, value); }
static constexpr bool can_write = !std::is_same_v<std::nullptr_t, decltype(entity_field<Obj, Type, R, W, Ts...>::writer)>;
static constexpr field_status is_enabled(const Predicate & p, const Obj& x);
constexpr field_status is_enabled(const Obj& x) const { return is_enabled(predicate, x); }
static constexpr std::pair<Type, Type> get_range(const Range& r, const Obj& x);
constexpr std::pair<Type, Type> get_range(const Obj& x) const { return get_range(range, x); }
static constexpr std::size_t get_max_length(const Length& l, const Obj& x);
constexpr std::size_t get_max_length(const Obj& x) const { return get_max_length(length, x); }
static constexpr StringView get_group(const Group& g, const Obj& x);
constexpr StringView get_group(const Obj& x) const { return get_group(group, x); }
constexpr entity_field(StringView name, R r, W w, Ts&&... ts) noexcept :
name{name}, reader{r}, writer{w},
predicate { std::get<c_predicate::index>(std::forward_as_tuple(ts..., default_predicate)) },
range { std::get<c_range::index> (std::forward_as_tuple(ts..., default_c_range)) },
length { std::get<c_length::index> (std::forward_as_tuple(ts..., default_c_length)) },
group { std::get<c_group::index> (std::forward_as_tuple(ts..., default_c_group)) }
{}
constexpr erased_accessor erased() const;
};
template<typename Obj, typename Type, FieldReader<Obj, Type> R, FieldWriter<Obj, Type> W, typename... Ts>
constexpr void entity_field<Obj, Type, R, W, Ts...>::write(const W& writer, Obj& x, move_qualified<Type> v)
{
static_assert(can_write); detail::write_field<Obj, Type, W>::write(x, writer, v);
}
template<typename Obj, typename Type, FieldReader<Obj, Type> R, FieldWriter<Obj, Type> W, typename... Ts>
constexpr erased_accessor entity_field<Obj, Type, R, W, Ts...>::erased() const
{
using reader_t = typename erased_accessor::erased_reader_t;
using writer_t = typename erased_accessor::erased_writer_t;
using predicate_t = typename erased_accessor::erased_predicate_t ;
constexpr auto obj_name = name_of<Obj>, field_name = name_of<Type>;
using P = Predicate;
constexpr auto reader_fn = [](const void* obj, const reader_t* reader, void* value) {
const auto& obj_ = *reinterpret_cast<const Obj*>(obj);
const auto& reader_ = *reinterpret_cast<const R*>(reader);
auto& value_ = *reinterpret_cast<Type*>(value);
value_ = read(reader_, obj_);
};
constexpr auto writer_fn = [](void* obj, const writer_t* writer, void* value) {
auto& obj_ = *reinterpret_cast<Obj*>(obj);
const auto& writer_ = *reinterpret_cast<const W*>(writer);
move_qualified<Type> value_ = std::move(*reinterpret_cast<Type*>(value));
write(writer_, obj_, value_);
};
constexpr auto predicate_fn = [](const void* obj, const predicate_t* predicate) {
const auto& obj_ = *reinterpret_cast<const Obj*>(obj);
const auto& predicate_ = *reinterpret_cast<const P*>(predicate);
return is_enabled(predicate_, obj_);
};
constexpr auto writer_stub_fn = [](void*, const writer_t*, void*) {
fm_abort("no writer for this accessor");
};
return erased_accessor {
(void*)&reader, writer ? (void*)&writer : nullptr, (void*)&predicate,
name, obj_name, field_name,
reader_fn, writer ? writer_fn : writer_stub_fn, predicate_fn,
};
}
template<typename Obj, typename Type, FieldReader<Obj, Type> R, FieldWriter<Obj, Type> W, typename... Ts>
constexpr field_status entity_field<Obj, Type, R, W, Ts...>::is_enabled(const Predicate& p, const Obj& x)
{ return detail::read_field<Obj, field_status, Predicate>::read(x, p); }
template<typename Obj, typename Type, FieldReader<Obj, Type> R, FieldWriter<Obj, Type> W, typename... Ts>
constexpr std::pair<Type, Type> entity_field<Obj, Type, R, W, Ts...>::get_range(const Range& r, const Obj& x)
{ return detail::read_field<Obj, constraints::range<Type>, Range>::read(x, r); }
template<typename Obj, typename Type, FieldReader<Obj, Type> R, FieldWriter<Obj, Type> W, typename... Ts>
constexpr std::size_t entity_field<Obj, Type, R, W, Ts...>::get_max_length(const Length& l, const Obj& x)
{ return detail::read_field<Obj, constraints::length, Length>::read(x, l); }
template<typename Obj, typename Type, FieldReader<Obj, Type> R, FieldWriter<Obj, Type> W, typename... Ts>
constexpr StringView entity_field<Obj, Type, R, W, Ts...>::get_group(const Group& g, const Obj& x)
{ return detail::read_field<Obj, constraints::group, Group>::read(x, g); }
template<typename Obj>
struct Entity final {
static_assert(std::is_same_v<Obj, std::decay_t<Obj>>);
template<typename Type>
struct type final
{
template<FieldReader<Obj, Type> R, FieldWriter<Obj, Type> W, typename... Ts>
struct field final : entity_field<Obj, Type, R, W, Ts...>
{
constexpr field(StringView field_name, R r, W w, Ts&&... ts) noexcept :
entity_field<Obj, Type, R, W, Ts...>{field_name, r, w, std::forward<Ts>(ts)...}
{}
};
template<FieldReader<Obj, Type> R, FieldWriter<Obj, Type> W, typename... Ts>
field(StringView name, R r, W w, Ts&&... ts) -> field<R, W, Ts...>;
};
};
template<typename F, typename Tuple>
constexpr void visit_tuple(F&& fun, Tuple&& tuple)
{
using Size = std::tuple_size<std::decay_t<Tuple>>;
if constexpr(Size() > 0)
detail::visit_tuple<F, Tuple, 0>(std::forward<F>(fun), std::forward<Tuple>(tuple));
}
template<typename F, typename Tuple>
constexpr bool find_in_tuple(F&& fun, Tuple&& tuple)
{
using Size = std::tuple_size<std::decay_t<Tuple>>;
if constexpr(Size() > 0)
return detail::find_in_tuple<F, Tuple, 0>(std::forward<F>(fun), std::forward<Tuple>(tuple));
else
return false;
}
} // namespace floormat::entities
namespace floormat {
template<typename T>
requires std::is_same_v<T, std::decay_t<T>>
class entity_metadata final {
template<typename... Ts>
static consteval auto erased_helper(const std::tuple<Ts...>& tuple)
{
std::array<entities::erased_accessor, sizeof...(Ts)> array { std::get<Ts>(tuple).erased()..., };
return array;
}
public:
static constexpr StringView class_name = name_of<T>;
static constexpr std::size_t size = std::tuple_size_v<entities::detail::accessors_for<T>>;
static constexpr entities::detail::accessors_for<T> accessors = T::accessors();
static constexpr auto erased_accessors = erased_helper(accessors);
};
} // namespace floormat
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