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- #ifndef ENTT_ENTITY_STORAGE_HPP
- #define ENTT_ENTITY_STORAGE_HPP
-
- #include <cstddef>
- #include <iterator>
- #include <memory>
- #include <tuple>
- #include <type_traits>
- #include <utility>
- #include <vector>
- #include "../config/config.h"
- #include "../core/compressed_pair.hpp"
- #include "../core/iterator.hpp"
- #include "../core/memory.hpp"
- #include "../core/type_info.hpp"
- #include "component.hpp"
- #include "entity.hpp"
- #include "fwd.hpp"
- #include "sigh_storage_mixin.hpp"
- #include "sparse_set.hpp"
-
- namespace entt {
-
- /**
- * @cond TURN_OFF_DOXYGEN
- * Internal details not to be documented.
- */
-
- namespace internal {
-
- template<typename Container>
- class storage_iterator final {
- friend storage_iterator<const Container>;
-
- using container_type = std::remove_const_t<Container>;
- using alloc_traits = std::allocator_traits<typename container_type::allocator_type>;
- using comp_traits = component_traits<typename container_type::value_type>;
-
- using iterator_traits = std::iterator_traits<std::conditional_t<
- std::is_const_v<Container>,
- typename alloc_traits::template rebind_traits<typename std::pointer_traits<typename container_type::value_type>::element_type>::const_pointer,
- typename alloc_traits::template rebind_traits<typename std::pointer_traits<typename container_type::value_type>::element_type>::pointer>>;
-
- public:
- using value_type = typename iterator_traits::value_type;
- using pointer = typename iterator_traits::pointer;
- using reference = typename iterator_traits::reference;
- using difference_type = typename iterator_traits::difference_type;
- using iterator_category = std::random_access_iterator_tag;
-
- storage_iterator() ENTT_NOEXCEPT = default;
-
- storage_iterator(Container *ref, difference_type idx) ENTT_NOEXCEPT
- : packed{ref},
- offset{idx} {}
-
- template<bool Const = std::is_const_v<Container>, typename = std::enable_if_t<Const>>
- storage_iterator(const storage_iterator<std::remove_const_t<Container>> &other) ENTT_NOEXCEPT
- : packed{other.packed},
- offset{other.offset} {}
-
- storage_iterator &operator++() ENTT_NOEXCEPT {
- return --offset, *this;
- }
-
- storage_iterator operator++(int) ENTT_NOEXCEPT {
- storage_iterator orig = *this;
- return ++(*this), orig;
- }
-
- storage_iterator &operator--() ENTT_NOEXCEPT {
- return ++offset, *this;
- }
-
- storage_iterator operator--(int) ENTT_NOEXCEPT {
- storage_iterator orig = *this;
- return operator--(), orig;
- }
-
- storage_iterator &operator+=(const difference_type value) ENTT_NOEXCEPT {
- offset -= value;
- return *this;
- }
-
- storage_iterator operator+(const difference_type value) const ENTT_NOEXCEPT {
- storage_iterator copy = *this;
- return (copy += value);
- }
-
- storage_iterator &operator-=(const difference_type value) ENTT_NOEXCEPT {
- return (*this += -value);
- }
-
- storage_iterator operator-(const difference_type value) const ENTT_NOEXCEPT {
- return (*this + -value);
- }
-
- [[nodiscard]] reference operator[](const difference_type value) const ENTT_NOEXCEPT {
- const auto pos = index() - value;
- return (*packed)[pos / comp_traits::page_size][fast_mod(pos, comp_traits::page_size)];
- }
-
- [[nodiscard]] pointer operator->() const ENTT_NOEXCEPT {
- const auto pos = index();
- return (*packed)[pos / comp_traits::page_size] + fast_mod(pos, comp_traits::page_size);
- }
-
- [[nodiscard]] reference operator*() const ENTT_NOEXCEPT {
- return *operator->();
- }
-
- [[nodiscard]] difference_type index() const ENTT_NOEXCEPT {
- return offset - 1;
- }
-
- private:
- Container *packed;
- difference_type offset;
- };
-
- template<typename CLhs, typename CRhs>
- [[nodiscard]] std::ptrdiff_t operator-(const storage_iterator<CLhs> &lhs, const storage_iterator<CRhs> &rhs) ENTT_NOEXCEPT {
- return rhs.index() - lhs.index();
- }
-
- template<typename CLhs, typename CRhs>
- [[nodiscard]] bool operator==(const storage_iterator<CLhs> &lhs, const storage_iterator<CRhs> &rhs) ENTT_NOEXCEPT {
- return lhs.index() == rhs.index();
- }
-
- template<typename CLhs, typename CRhs>
- [[nodiscard]] bool operator!=(const storage_iterator<CLhs> &lhs, const storage_iterator<CRhs> &rhs) ENTT_NOEXCEPT {
- return !(lhs == rhs);
- }
-
- template<typename CLhs, typename CRhs>
- [[nodiscard]] bool operator<(const storage_iterator<CLhs> &lhs, const storage_iterator<CRhs> &rhs) ENTT_NOEXCEPT {
- return lhs.index() > rhs.index();
- }
-
- template<typename CLhs, typename CRhs>
- [[nodiscard]] bool operator>(const storage_iterator<CLhs> &lhs, const storage_iterator<CRhs> &rhs) ENTT_NOEXCEPT {
- return lhs.index() < rhs.index();
- }
-
- template<typename CLhs, typename CRhs>
- [[nodiscard]] bool operator<=(const storage_iterator<CLhs> &lhs, const storage_iterator<CRhs> &rhs) ENTT_NOEXCEPT {
- return !(lhs > rhs);
- }
-
- template<typename CLhs, typename CRhs>
- [[nodiscard]] bool operator>=(const storage_iterator<CLhs> &lhs, const storage_iterator<CRhs> &rhs) ENTT_NOEXCEPT {
- return !(lhs < rhs);
- }
-
- template<typename It, typename... Other>
- class extended_storage_iterator final {
- template<typename Iter, typename... Args>
- friend class extended_storage_iterator;
-
- public:
- using value_type = decltype(std::tuple_cat(std::make_tuple(*std::declval<It>()), std::forward_as_tuple(*std::declval<Other>()...)));
- using pointer = input_iterator_pointer<value_type>;
- using reference = value_type;
- using difference_type = std::ptrdiff_t;
- using iterator_category = std::input_iterator_tag;
-
- extended_storage_iterator() = default;
-
- extended_storage_iterator(It base, Other... other)
- : it{base, other...} {}
-
- template<typename... Args, typename = std::enable_if_t<(!std::is_same_v<Other, Args> && ...) && (std::is_constructible_v<Other, Args> && ...)>>
- extended_storage_iterator(const extended_storage_iterator<It, Args...> &other)
- : it{other.it} {}
-
- extended_storage_iterator &operator++() ENTT_NOEXCEPT {
- return ++std::get<It>(it), (++std::get<Other>(it), ...), *this;
- }
-
- extended_storage_iterator operator++(int) ENTT_NOEXCEPT {
- extended_storage_iterator orig = *this;
- return ++(*this), orig;
- }
-
- [[nodiscard]] pointer operator->() const ENTT_NOEXCEPT {
- return operator*();
- }
-
- [[nodiscard]] reference operator*() const ENTT_NOEXCEPT {
- return {*std::get<It>(it), *std::get<Other>(it)...};
- }
-
- template<typename... CLhs, typename... CRhs>
- friend bool operator==(const extended_storage_iterator<CLhs...> &, const extended_storage_iterator<CRhs...> &) ENTT_NOEXCEPT;
-
- private:
- std::tuple<It, Other...> it;
- };
-
- template<typename... CLhs, typename... CRhs>
- [[nodiscard]] bool operator==(const extended_storage_iterator<CLhs...> &lhs, const extended_storage_iterator<CRhs...> &rhs) ENTT_NOEXCEPT {
- return std::get<0>(lhs.it) == std::get<0>(rhs.it);
- }
-
- template<typename... CLhs, typename... CRhs>
- [[nodiscard]] bool operator!=(const extended_storage_iterator<CLhs...> &lhs, const extended_storage_iterator<CRhs...> &rhs) ENTT_NOEXCEPT {
- return !(lhs == rhs);
- }
-
- } // namespace internal
-
- /**
- * Internal details not to be documented.
- * @endcond
- */
-
- /**
- * @brief Basic storage implementation.
- *
- * Internal data structures arrange elements to maximize performance. There are
- * no guarantees that objects are returned in the insertion order when iterate
- * a storage. Do not make assumption on the order in any case.
- *
- * @warning
- * Empty types aren't explicitly instantiated. Therefore, many of the functions
- * normally available for non-empty types will not be available for empty ones.
- *
- * @tparam Entity A valid entity type (see entt_traits for more details).
- * @tparam Type Type of objects assigned to the entities.
- * @tparam Allocator Type of allocator used to manage memory and elements.
- */
- template<typename Entity, typename Type, typename Allocator, typename>
- class basic_storage: public basic_sparse_set<Entity, typename std::allocator_traits<Allocator>::template rebind_alloc<Entity>> {
- static_assert(std::is_move_constructible_v<Type> && std::is_move_assignable_v<Type>, "The type must be at least move constructible/assignable");
-
- using alloc_traits = std::allocator_traits<Allocator>;
- static_assert(std::is_same_v<typename alloc_traits::value_type, Type>, "Invalid value type");
- using underlying_type = basic_sparse_set<Entity, typename alloc_traits::template rebind_alloc<Entity>>;
- using container_type = std::vector<typename alloc_traits::pointer, typename alloc_traits::template rebind_alloc<typename alloc_traits::pointer>>;
- using comp_traits = component_traits<Type>;
-
- [[nodiscard]] auto &element_at(const std::size_t pos) const {
- return packed.first()[pos / comp_traits::page_size][fast_mod(pos, comp_traits::page_size)];
- }
-
- auto assure_at_least(const std::size_t pos) {
- auto &&container = packed.first();
- const auto idx = pos / comp_traits::page_size;
-
- if(!(idx < container.size())) {
- auto curr = container.size();
- container.resize(idx + 1u, nullptr);
-
- ENTT_TRY {
- for(const auto last = container.size(); curr < last; ++curr) {
- container[curr] = alloc_traits::allocate(packed.second(), comp_traits::page_size);
- }
- }
- ENTT_CATCH {
- container.resize(curr);
- ENTT_THROW;
- }
- }
-
- return container[idx] + fast_mod(pos, comp_traits::page_size);
- }
-
- template<typename... Args>
- auto emplace_element(const Entity entt, const bool force_back, Args &&...args) {
- const auto it = base_type::try_emplace(entt, force_back);
-
- ENTT_TRY {
- auto elem = assure_at_least(static_cast<size_type>(it.index()));
- entt::uninitialized_construct_using_allocator(to_address(elem), packed.second(), std::forward<Args>(args)...);
- }
- ENTT_CATCH {
- if constexpr(comp_traits::in_place_delete) {
- base_type::in_place_pop(it, it + 1u);
- } else {
- base_type::swap_and_pop(it, it + 1u);
- }
-
- ENTT_THROW;
- }
-
- return it;
- }
-
- void shrink_to_size(const std::size_t sz) {
- for(auto pos = sz, length = base_type::size(); pos < length; ++pos) {
- if constexpr(comp_traits::in_place_delete) {
- if(base_type::at(pos) != tombstone) {
- std::destroy_at(std::addressof(element_at(pos)));
- }
- } else {
- std::destroy_at(std::addressof(element_at(pos)));
- }
- }
-
- auto &&container = packed.first();
- auto page_allocator{packed.second()};
- const auto from = (sz + comp_traits::page_size - 1u) / comp_traits::page_size;
-
- for(auto pos = from, last = container.size(); pos < last; ++pos) {
- alloc_traits::deallocate(page_allocator, container[pos], comp_traits::page_size);
- }
-
- container.resize(from);
- }
-
- private:
- const void *get_at(const std::size_t pos) const final {
- return std::addressof(element_at(pos));
- }
-
- void swap_at(const std::size_t lhs, const std::size_t rhs) final {
- using std::swap;
- swap(element_at(lhs), element_at(rhs));
- }
-
- void move_element(const std::size_t from, const std::size_t to) final {
- auto &elem = element_at(from);
- entt::uninitialized_construct_using_allocator(to_address(assure_at_least(to)), packed.second(), std::move(elem));
- std::destroy_at(std::addressof(elem));
- }
-
- protected:
- /**
- * @brief Erases elements from a storage.
- * @param first An iterator to the first element to erase.
- * @param last An iterator past the last element to erase.
- */
- void swap_and_pop(typename underlying_type::basic_iterator first, typename underlying_type::basic_iterator last) override {
- for(; first != last; ++first) {
- // cannot use first::index() because it would break with cross iterators
- const auto pos = base_type::index(*first);
- auto &elem = element_at(base_type::size() - 1u);
- // destroying on exit allows reentrant destructors
- [[maybe_unused]] auto unused = std::exchange(element_at(pos), std::move(elem));
- std::destroy_at(std::addressof(elem));
- base_type::swap_and_pop(first, first + 1u);
- }
- }
-
- /**
- * @brief Erases elements from a storage.
- * @param first An iterator to the first element to erase.
- * @param last An iterator past the last element to erase.
- */
- void in_place_pop(typename underlying_type::basic_iterator first, typename underlying_type::basic_iterator last) override {
- for(; first != last; ++first) {
- // cannot use first::index() because it would break with cross iterators
- const auto pos = base_type::index(*first);
- base_type::in_place_pop(first, first + 1u);
- std::destroy_at(std::addressof(element_at(pos)));
- }
- }
-
- /**
- * @brief Assigns an entity to a storage.
- * @param entt A valid identifier.
- * @param value Optional opaque value.
- * @param force_back Force back insertion.
- * @return Iterator pointing to the emplaced element.
- */
- typename underlying_type::basic_iterator try_emplace([[maybe_unused]] const Entity entt, const bool force_back, const void *value) override {
- if(value) {
- if constexpr(std::is_copy_constructible_v<value_type>) {
- return emplace_element(entt, force_back, *static_cast<const value_type *>(value));
- } else {
- return base_type::end();
- }
- } else {
- if constexpr(std::is_default_constructible_v<value_type>) {
- return emplace_element(entt, force_back);
- } else {
- return base_type::end();
- }
- }
- }
-
- public:
- /*! @brief Base type. */
- using base_type = underlying_type;
- /*! @brief Allocator type. */
- using allocator_type = Allocator;
- /*! @brief Type of the objects assigned to entities. */
- using value_type = Type;
- /*! @brief Underlying entity identifier. */
- using entity_type = Entity;
- /*! @brief Unsigned integer type. */
- using size_type = std::size_t;
- /*! @brief Pointer type to contained elements. */
- using pointer = typename container_type::pointer;
- /*! @brief Constant pointer type to contained elements. */
- using const_pointer = typename alloc_traits::template rebind_traits<typename alloc_traits::const_pointer>::const_pointer;
- /*! @brief Random access iterator type. */
- using iterator = internal::storage_iterator<container_type>;
- /*! @brief Constant random access iterator type. */
- using const_iterator = internal::storage_iterator<const container_type>;
- /*! @brief Reverse iterator type. */
- using reverse_iterator = std::reverse_iterator<iterator>;
- /*! @brief Constant reverse iterator type. */
- using const_reverse_iterator = std::reverse_iterator<const_iterator>;
- /*! @brief Extended iterable storage proxy. */
- using iterable = iterable_adaptor<internal::extended_storage_iterator<typename base_type::iterator, iterator>>;
- /*! @brief Constant extended iterable storage proxy. */
- using const_iterable = iterable_adaptor<internal::extended_storage_iterator<typename base_type::const_iterator, const_iterator>>;
-
- /*! @brief Default constructor. */
- basic_storage()
- : basic_storage{allocator_type{}} {}
-
- /**
- * @brief Constructs an empty storage with a given allocator.
- * @param allocator The allocator to use.
- */
- explicit basic_storage(const allocator_type &allocator)
- : base_type{type_id<value_type>(), deletion_policy{comp_traits::in_place_delete}, allocator},
- packed{container_type{allocator}, allocator} {}
-
- /**
- * @brief Move constructor.
- * @param other The instance to move from.
- */
- basic_storage(basic_storage &&other) ENTT_NOEXCEPT
- : base_type{std::move(other)},
- packed{std::move(other.packed)} {}
-
- /**
- * @brief Allocator-extended move constructor.
- * @param other The instance to move from.
- * @param allocator The allocator to use.
- */
- basic_storage(basic_storage &&other, const allocator_type &allocator) ENTT_NOEXCEPT
- : base_type{std::move(other), allocator},
- packed{container_type{std::move(other.packed.first()), allocator}, allocator} {
- ENTT_ASSERT(alloc_traits::is_always_equal::value || packed.second() == other.packed.second(), "Copying a storage is not allowed");
- }
-
- /*! @brief Default destructor. */
- ~basic_storage() override {
- shrink_to_size(0u);
- }
-
- /**
- * @brief Move assignment operator.
- * @param other The instance to move from.
- * @return This storage.
- */
- basic_storage &operator=(basic_storage &&other) ENTT_NOEXCEPT {
- ENTT_ASSERT(alloc_traits::is_always_equal::value || packed.second() == other.packed.second(), "Copying a storage is not allowed");
-
- shrink_to_size(0u);
- base_type::operator=(std::move(other));
- packed.first() = std::move(other.packed.first());
- propagate_on_container_move_assignment(packed.second(), other.packed.second());
- return *this;
- }
-
- /**
- * @brief Exchanges the contents with those of a given storage.
- * @param other Storage to exchange the content with.
- */
- void swap(basic_storage &other) {
- using std::swap;
- underlying_type::swap(other);
- propagate_on_container_swap(packed.second(), other.packed.second());
- swap(packed.first(), other.packed.first());
- }
-
- /**
- * @brief Returns the associated allocator.
- * @return The associated allocator.
- */
- [[nodiscard]] constexpr allocator_type get_allocator() const ENTT_NOEXCEPT {
- return allocator_type{packed.second()};
- }
-
- /**
- * @brief Increases the capacity of a storage.
- *
- * If the new capacity is greater than the current capacity, new storage is
- * allocated, otherwise the method does nothing.
- *
- * @param cap Desired capacity.
- */
- void reserve(const size_type cap) override {
- if(cap != 0u) {
- base_type::reserve(cap);
- assure_at_least(cap - 1u);
- }
- }
-
- /**
- * @brief Returns the number of elements that a storage has currently
- * allocated space for.
- * @return Capacity of the storage.
- */
- [[nodiscard]] size_type capacity() const ENTT_NOEXCEPT override {
- return packed.first().size() * comp_traits::page_size;
- }
-
- /*! @brief Requests the removal of unused capacity. */
- void shrink_to_fit() override {
- base_type::shrink_to_fit();
- shrink_to_size(base_type::size());
- }
-
- /**
- * @brief Direct access to the array of objects.
- * @return A pointer to the array of objects.
- */
- [[nodiscard]] const_pointer raw() const ENTT_NOEXCEPT {
- return packed.first().data();
- }
-
- /*! @copydoc raw */
- [[nodiscard]] pointer raw() ENTT_NOEXCEPT {
- return packed.first().data();
- }
-
- /**
- * @brief Returns an iterator to the beginning.
- *
- * The returned iterator points to the first instance of the internal array.
- * If the storage is empty, the returned iterator will be equal to `end()`.
- *
- * @return An iterator to the first instance of the internal array.
- */
- [[nodiscard]] const_iterator cbegin() const ENTT_NOEXCEPT {
- const auto pos = static_cast<typename iterator::difference_type>(base_type::size());
- return const_iterator{&packed.first(), pos};
- }
-
- /*! @copydoc cbegin */
- [[nodiscard]] const_iterator begin() const ENTT_NOEXCEPT {
- return cbegin();
- }
-
- /*! @copydoc begin */
- [[nodiscard]] iterator begin() ENTT_NOEXCEPT {
- const auto pos = static_cast<typename iterator::difference_type>(base_type::size());
- return iterator{&packed.first(), pos};
- }
-
- /**
- * @brief Returns an iterator to the end.
- *
- * The returned iterator points to the element following the last instance
- * of the internal array. Attempting to dereference the returned iterator
- * results in undefined behavior.
- *
- * @return An iterator to the element following the last instance of the
- * internal array.
- */
- [[nodiscard]] const_iterator cend() const ENTT_NOEXCEPT {
- return const_iterator{&packed.first(), {}};
- }
-
- /*! @copydoc cend */
- [[nodiscard]] const_iterator end() const ENTT_NOEXCEPT {
- return cend();
- }
-
- /*! @copydoc end */
- [[nodiscard]] iterator end() ENTT_NOEXCEPT {
- return iterator{&packed.first(), {}};
- }
-
- /**
- * @brief Returns a reverse iterator to the beginning.
- *
- * The returned iterator points to the first instance of the reversed
- * internal array. If the storage is empty, the returned iterator will be
- * equal to `rend()`.
- *
- * @return An iterator to the first instance of the reversed internal array.
- */
- [[nodiscard]] const_reverse_iterator crbegin() const ENTT_NOEXCEPT {
- return std::make_reverse_iterator(cend());
- }
-
- /*! @copydoc crbegin */
- [[nodiscard]] const_reverse_iterator rbegin() const ENTT_NOEXCEPT {
- return crbegin();
- }
-
- /*! @copydoc rbegin */
- [[nodiscard]] reverse_iterator rbegin() ENTT_NOEXCEPT {
- return std::make_reverse_iterator(end());
- }
-
- /**
- * @brief Returns a reverse iterator to the end.
- *
- * The returned iterator points to the element following the last instance
- * of the reversed internal array. Attempting to dereference the returned
- * iterator results in undefined behavior.
- *
- * @return An iterator to the element following the last instance of the
- * reversed internal array.
- */
- [[nodiscard]] const_reverse_iterator crend() const ENTT_NOEXCEPT {
- return std::make_reverse_iterator(cbegin());
- }
-
- /*! @copydoc crend */
- [[nodiscard]] const_reverse_iterator rend() const ENTT_NOEXCEPT {
- return crend();
- }
-
- /*! @copydoc rend */
- [[nodiscard]] reverse_iterator rend() ENTT_NOEXCEPT {
- return std::make_reverse_iterator(begin());
- }
-
- /**
- * @brief Returns the object assigned to an entity.
- *
- * @warning
- * Attempting to use an entity that doesn't belong to the storage results in
- * undefined behavior.
- *
- * @param entt A valid identifier.
- * @return The object assigned to the entity.
- */
- [[nodiscard]] const value_type &get(const entity_type entt) const ENTT_NOEXCEPT {
- return element_at(base_type::index(entt));
- }
-
- /*! @copydoc get */
- [[nodiscard]] value_type &get(const entity_type entt) ENTT_NOEXCEPT {
- return const_cast<value_type &>(std::as_const(*this).get(entt));
- }
-
- /**
- * @brief Returns the object assigned to an entity as a tuple.
- * @param entt A valid identifier.
- * @return The object assigned to the entity as a tuple.
- */
- [[nodiscard]] std::tuple<const value_type &> get_as_tuple(const entity_type entt) const ENTT_NOEXCEPT {
- return std::forward_as_tuple(get(entt));
- }
-
- /*! @copydoc get_as_tuple */
- [[nodiscard]] std::tuple<value_type &> get_as_tuple(const entity_type entt) ENTT_NOEXCEPT {
- return std::forward_as_tuple(get(entt));
- }
-
- /**
- * @brief Assigns an entity to a storage and constructs its object.
- *
- * @warning
- * Attempting to use an entity that already belongs to the storage results
- * in undefined behavior.
- *
- * @tparam Args Types of arguments to use to construct the object.
- * @param entt A valid identifier.
- * @param args Parameters to use to construct an object for the entity.
- * @return A reference to the newly created object.
- */
- template<typename... Args>
- value_type &emplace(const entity_type entt, Args &&...args) {
- if constexpr(std::is_aggregate_v<value_type>) {
- const auto it = emplace_element(entt, false, Type{std::forward<Args>(args)...});
- return element_at(static_cast<size_type>(it.index()));
- } else {
- const auto it = emplace_element(entt, false, std::forward<Args>(args)...);
- return element_at(static_cast<size_type>(it.index()));
- }
- }
-
- /**
- * @brief Updates the instance assigned to a given entity in-place.
- * @tparam Func Types of the function objects to invoke.
- * @param entt A valid identifier.
- * @param func Valid function objects.
- * @return A reference to the updated instance.
- */
- template<typename... Func>
- value_type &patch(const entity_type entt, Func &&...func) {
- const auto idx = base_type::index(entt);
- auto &elem = element_at(idx);
- (std::forward<Func>(func)(elem), ...);
- return elem;
- }
-
- /**
- * @brief Assigns one or more entities to a storage and constructs their
- * objects from a given instance.
- *
- * @warning
- * Attempting to assign an entity that already belongs to the storage
- * results in undefined behavior.
- *
- * @tparam It Type of input iterator.
- * @param first An iterator to the first element of the range of entities.
- * @param last An iterator past the last element of the range of entities.
- * @param value An instance of the object to construct.
- */
- template<typename It>
- void insert(It first, It last, const value_type &value = {}) {
- for(; first != last; ++first) {
- emplace_element(*first, true, value);
- }
- }
-
- /**
- * @brief Assigns one or more entities to a storage and constructs their
- * objects from a given range.
- *
- * @sa construct
- *
- * @tparam EIt Type of input iterator.
- * @tparam CIt Type of input iterator.
- * @param first An iterator to the first element of the range of entities.
- * @param last An iterator past the last element of the range of entities.
- * @param from An iterator to the first element of the range of objects.
- */
- template<typename EIt, typename CIt, typename = std::enable_if_t<std::is_same_v<typename std::iterator_traits<CIt>::value_type, value_type>>>
- void insert(EIt first, EIt last, CIt from) {
- for(; first != last; ++first, ++from) {
- emplace_element(*first, true, *from);
- }
- }
-
- /**
- * @brief Returns an iterable object to use to _visit_ a storage.
- *
- * The iterable object returns a tuple that contains the current entity and
- * a reference to its component.
- *
- * @return An iterable object to use to _visit_ the storage.
- */
- [[nodiscard]] iterable each() ENTT_NOEXCEPT {
- return {internal::extended_storage_iterator{base_type::begin(), begin()}, internal::extended_storage_iterator{base_type::end(), end()}};
- }
-
- /*! @copydoc each */
- [[nodiscard]] const_iterable each() const ENTT_NOEXCEPT {
- return {internal::extended_storage_iterator{base_type::cbegin(), cbegin()}, internal::extended_storage_iterator{base_type::cend(), cend()}};
- }
-
- private:
- compressed_pair<container_type, allocator_type> packed;
- };
-
- /*! @copydoc basic_storage */
- template<typename Entity, typename Type, typename Allocator>
- class basic_storage<Entity, Type, Allocator, std::enable_if_t<ignore_as_empty_v<Type>>>
- : public basic_sparse_set<Entity, typename std::allocator_traits<Allocator>::template rebind_alloc<Entity>> {
- using alloc_traits = std::allocator_traits<Allocator>;
- static_assert(std::is_same_v<typename alloc_traits::value_type, Type>, "Invalid value type");
- using underlying_type = basic_sparse_set<Entity, typename alloc_traits::template rebind_alloc<Entity>>;
- using comp_traits = component_traits<Type>;
-
- public:
- /*! @brief Base type. */
- using base_type = underlying_type;
- /*! @brief Allocator type. */
- using allocator_type = Allocator;
- /*! @brief Type of the objects assigned to entities. */
- using value_type = Type;
- /*! @brief Underlying entity identifier. */
- using entity_type = Entity;
- /*! @brief Unsigned integer type. */
- using size_type = std::size_t;
- /*! @brief Extended iterable storage proxy. */
- using iterable = iterable_adaptor<internal::extended_storage_iterator<typename base_type::iterator>>;
- /*! @brief Constant extended iterable storage proxy. */
- using const_iterable = iterable_adaptor<internal::extended_storage_iterator<typename base_type::const_iterator>>;
-
- /*! @brief Default constructor. */
- basic_storage()
- : basic_storage{allocator_type{}} {}
-
- /**
- * @brief Constructs an empty container with a given allocator.
- * @param allocator The allocator to use.
- */
- explicit basic_storage(const allocator_type &allocator)
- : base_type{type_id<value_type>(), deletion_policy{comp_traits::in_place_delete}, allocator} {}
-
- /**
- * @brief Move constructor.
- * @param other The instance to move from.
- */
- basic_storage(basic_storage &&other) ENTT_NOEXCEPT = default;
-
- /**
- * @brief Allocator-extended move constructor.
- * @param other The instance to move from.
- * @param allocator The allocator to use.
- */
- basic_storage(basic_storage &&other, const allocator_type &allocator) ENTT_NOEXCEPT
- : base_type{std::move(other), allocator} {}
-
- /**
- * @brief Move assignment operator.
- * @param other The instance to move from.
- * @return This storage.
- */
- basic_storage &operator=(basic_storage &&other) ENTT_NOEXCEPT = default;
-
- /**
- * @brief Returns the associated allocator.
- * @return The associated allocator.
- */
- [[nodiscard]] constexpr allocator_type get_allocator() const ENTT_NOEXCEPT {
- return allocator_type{base_type::get_allocator()};
- }
-
- /**
- * @brief Returns the object assigned to an entity, that is `void`.
- *
- * @warning
- * Attempting to use an entity that doesn't belong to the storage results in
- * undefined behavior.
- *
- * @param entt A valid identifier.
- */
- void get([[maybe_unused]] const entity_type entt) const ENTT_NOEXCEPT {
- ENTT_ASSERT(base_type::contains(entt), "Storage does not contain entity");
- }
-
- /**
- * @brief Returns an empty tuple.
- *
- * @warning
- * Attempting to use an entity that doesn't belong to the storage results in
- * undefined behavior.
- *
- * @param entt A valid identifier.
- * @return Returns an empty tuple.
- */
- [[nodiscard]] std::tuple<> get_as_tuple([[maybe_unused]] const entity_type entt) const ENTT_NOEXCEPT {
- ENTT_ASSERT(base_type::contains(entt), "Storage does not contain entity");
- return std::tuple{};
- }
-
- /**
- * @brief Assigns an entity to a storage and constructs its object.
- *
- * @warning
- * Attempting to use an entity that already belongs to the storage results
- * in undefined behavior.
- *
- * @tparam Args Types of arguments to use to construct the object.
- * @param entt A valid identifier.
- */
- template<typename... Args>
- void emplace(const entity_type entt, Args &&...) {
- base_type::try_emplace(entt, false);
- }
-
- /**
- * @brief Updates the instance assigned to a given entity in-place.
- * @tparam Func Types of the function objects to invoke.
- * @param entt A valid identifier.
- * @param func Valid function objects.
- */
- template<typename... Func>
- void patch([[maybe_unused]] const entity_type entt, Func &&...func) {
- ENTT_ASSERT(base_type::contains(entt), "Storage does not contain entity");
- (std::forward<Func>(func)(), ...);
- }
-
- /**
- * @brief Assigns entities to a storage.
- * @tparam It Type of input iterator.
- * @tparam Args Types of optional arguments.
- * @param first An iterator to the first element of the range of entities.
- * @param last An iterator past the last element of the range of entities.
- */
- template<typename It, typename... Args>
- void insert(It first, It last, Args &&...) {
- for(; first != last; ++first) {
- base_type::try_emplace(*first, true);
- }
- }
-
- /**
- * @brief Returns an iterable object to use to _visit_ a storage.
- *
- * The iterable object returns a tuple that contains the current entity.
- *
- * @return An iterable object to use to _visit_ the storage.
- */
- [[nodiscard]] iterable each() ENTT_NOEXCEPT {
- return {internal::extended_storage_iterator{base_type::begin()}, internal::extended_storage_iterator{base_type::end()}};
- }
-
- /*! @copydoc each */
- [[nodiscard]] const_iterable each() const ENTT_NOEXCEPT {
- return {internal::extended_storage_iterator{base_type::cbegin()}, internal::extended_storage_iterator{base_type::cend()}};
- }
- };
-
- /**
- * @brief Provides a common way to access certain properties of storage types.
- * @tparam Entity A valid entity type (see entt_traits for more details).
- * @tparam Type Type of objects managed by the storage class.
- */
- template<typename Entity, typename Type, typename = void>
- struct storage_traits {
- /*! @brief Resulting type after component-to-storage conversion. */
- using storage_type = sigh_storage_mixin<basic_storage<Entity, Type>>;
- };
-
- } // namespace entt
-
- #endif
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