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961 lines
34 KiB
961 lines
34 KiB
#ifndef ENTT_ENTITY_SPARSE_SET_HPP
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#define ENTT_ENTITY_SPARSE_SET_HPP
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#include <cstddef>
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#include <iterator>
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#include <memory>
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#include <type_traits>
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#include <utility>
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#include <vector>
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#include "../config/config.h"
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#include "../core/algorithm.hpp"
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#include "../core/any.hpp"
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#include "../core/memory.hpp"
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#include "../core/type_info.hpp"
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#include "entity.hpp"
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#include "fwd.hpp"
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namespace entt {
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/**
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* @cond TURN_OFF_DOXYGEN
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* Internal details not to be documented.
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*/
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namespace internal {
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template<typename Container>
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struct sparse_set_iterator final {
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using value_type = typename Container::value_type;
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using pointer = typename Container::const_pointer;
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using reference = typename Container::const_reference;
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using difference_type = typename Container::difference_type;
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using iterator_category = std::random_access_iterator_tag;
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sparse_set_iterator() ENTT_NOEXCEPT
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: packed{},
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offset{} {}
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sparse_set_iterator(const Container &ref, const difference_type idx) ENTT_NOEXCEPT
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: packed{std::addressof(ref)},
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offset{idx} {}
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sparse_set_iterator &operator++() ENTT_NOEXCEPT {
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return --offset, *this;
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}
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sparse_set_iterator operator++(int) ENTT_NOEXCEPT {
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sparse_set_iterator orig = *this;
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return ++(*this), orig;
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}
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sparse_set_iterator &operator--() ENTT_NOEXCEPT {
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return ++offset, *this;
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}
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sparse_set_iterator operator--(int) ENTT_NOEXCEPT {
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sparse_set_iterator orig = *this;
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return operator--(), orig;
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}
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sparse_set_iterator &operator+=(const difference_type value) ENTT_NOEXCEPT {
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offset -= value;
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return *this;
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}
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sparse_set_iterator operator+(const difference_type value) const ENTT_NOEXCEPT {
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sparse_set_iterator copy = *this;
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return (copy += value);
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}
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sparse_set_iterator &operator-=(const difference_type value) ENTT_NOEXCEPT {
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return (*this += -value);
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}
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sparse_set_iterator operator-(const difference_type value) const ENTT_NOEXCEPT {
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return (*this + -value);
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}
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[[nodiscard]] reference operator[](const difference_type value) const ENTT_NOEXCEPT {
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return packed->data()[index() - value];
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}
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[[nodiscard]] pointer operator->() const ENTT_NOEXCEPT {
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return packed->data() + index();
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}
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[[nodiscard]] reference operator*() const ENTT_NOEXCEPT {
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return *operator->();
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}
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[[nodiscard]] difference_type index() const ENTT_NOEXCEPT {
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return offset - 1;
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}
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private:
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const Container *packed;
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difference_type offset;
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};
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template<typename Type, typename Other>
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[[nodiscard]] std::ptrdiff_t operator-(const sparse_set_iterator<Type> &lhs, const sparse_set_iterator<Other> &rhs) ENTT_NOEXCEPT {
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return rhs.index() - lhs.index();
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}
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template<typename Type, typename Other>
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[[nodiscard]] bool operator==(const sparse_set_iterator<Type> &lhs, const sparse_set_iterator<Other> &rhs) ENTT_NOEXCEPT {
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return lhs.index() == rhs.index();
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}
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template<typename Type, typename Other>
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[[nodiscard]] bool operator!=(const sparse_set_iterator<Type> &lhs, const sparse_set_iterator<Other> &rhs) ENTT_NOEXCEPT {
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return !(lhs == rhs);
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}
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template<typename Type, typename Other>
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[[nodiscard]] bool operator<(const sparse_set_iterator<Type> &lhs, const sparse_set_iterator<Other> &rhs) ENTT_NOEXCEPT {
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return lhs.index() > rhs.index();
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}
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template<typename Type, typename Other>
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[[nodiscard]] bool operator>(const sparse_set_iterator<Type> &lhs, const sparse_set_iterator<Other> &rhs) ENTT_NOEXCEPT {
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return lhs.index() < rhs.index();
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}
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template<typename Type, typename Other>
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[[nodiscard]] bool operator<=(const sparse_set_iterator<Type> &lhs, const sparse_set_iterator<Other> &rhs) ENTT_NOEXCEPT {
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return !(lhs > rhs);
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}
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template<typename Type, typename Other>
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[[nodiscard]] bool operator>=(const sparse_set_iterator<Type> &lhs, const sparse_set_iterator<Other> &rhs) ENTT_NOEXCEPT {
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return !(lhs < rhs);
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}
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} // namespace internal
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/**
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* Internal details not to be documented.
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* @endcond
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*/
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/*! @brief Sparse set deletion policy. */
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enum class deletion_policy : std::uint8_t {
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/*! @brief Swap-and-pop deletion policy. */
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swap_and_pop = 0u,
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/*! @brief In-place deletion policy. */
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in_place = 1u
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};
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/**
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* @brief Basic sparse set implementation.
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*
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* Sparse set or packed array or whatever is the name users give it.<br/>
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* Two arrays: an _external_ one and an _internal_ one; a _sparse_ one and a
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* _packed_ one; one used for direct access through contiguous memory, the other
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* one used to get the data through an extra level of indirection.<br/>
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* This is largely used by the registry to offer users the fastest access ever
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* to the components. Views and groups in general are almost entirely designed
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* around sparse sets.
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*
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* This type of data structure is widely documented in the literature and on the
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* web. This is nothing more than a customized implementation suitable for the
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* purpose of the framework.
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*
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* @note
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* Internal data structures arrange elements to maximize performance. There are
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* no guarantees that entities are returned in the insertion order when iterate
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* a sparse set. Do not make assumption on the order in any case.
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*
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* @tparam Entity A valid entity type (see entt_traits for more details).
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* @tparam Allocator Type of allocator used to manage memory and elements.
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*/
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template<typename Entity, typename Allocator>
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class basic_sparse_set {
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using alloc_traits = std::allocator_traits<Allocator>;
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static_assert(std::is_same_v<typename alloc_traits::value_type, Entity>, "Invalid value type");
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using sparse_container_type = std::vector<typename alloc_traits::pointer, typename alloc_traits::template rebind_alloc<typename alloc_traits::pointer>>;
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using packed_container_type = std::vector<Entity, Allocator>;
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using entity_traits = entt_traits<Entity>;
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[[nodiscard]] auto sparse_ptr(const Entity entt) const {
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const auto pos = static_cast<size_type>(entity_traits::to_entity(entt));
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const auto page = pos / entity_traits::page_size;
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return (page < sparse.size() && sparse[page]) ? (sparse[page] + fast_mod(pos, entity_traits::page_size)) : nullptr;
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}
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[[nodiscard]] auto &sparse_ref(const Entity entt) const {
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ENTT_ASSERT(sparse_ptr(entt), "Invalid element");
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const auto pos = static_cast<size_type>(entity_traits::to_entity(entt));
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return sparse[pos / entity_traits::page_size][fast_mod(pos, entity_traits::page_size)];
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}
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[[nodiscard]] auto &assure_at_least(const Entity entt) {
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const auto pos = static_cast<size_type>(entity_traits::to_entity(entt));
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const auto page = pos / entity_traits::page_size;
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if(!(page < sparse.size())) {
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sparse.resize(page + 1u, nullptr);
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}
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if(!sparse[page]) {
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auto page_allocator{packed.get_allocator()};
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sparse[page] = alloc_traits::allocate(page_allocator, entity_traits::page_size);
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std::uninitialized_fill(sparse[page], sparse[page] + entity_traits::page_size, null);
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}
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auto &elem = sparse[page][fast_mod(pos, entity_traits::page_size)];
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ENTT_ASSERT(entity_traits::to_version(elem) == entity_traits::to_version(tombstone), "Slot not available");
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return elem;
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}
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void release_sparse_pages() {
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auto page_allocator{packed.get_allocator()};
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for(auto &&page: sparse) {
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if(page != nullptr) {
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std::destroy(page, page + entity_traits::page_size);
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alloc_traits::deallocate(page_allocator, page, entity_traits::page_size);
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page = nullptr;
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}
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}
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}
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private:
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virtual const void *get_at(const std::size_t) const {
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return nullptr;
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}
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virtual void swap_at(const std::size_t, const std::size_t) {}
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virtual void move_element(const std::size_t, const std::size_t) {}
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protected:
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/*! @brief Random access iterator type. */
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using basic_iterator = internal::sparse_set_iterator<packed_container_type>;
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/**
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* @brief Erases entities from a sparse set.
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* @param first An iterator to the first element of the range of entities.
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* @param last An iterator past the last element of the range of entities.
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*/
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virtual void swap_and_pop(basic_iterator first, basic_iterator last) {
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for(; first != last; ++first) {
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auto &self = sparse_ref(*first);
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const auto entt = entity_traits::to_entity(self);
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sparse_ref(packed.back()) = entity_traits::combine(entt, entity_traits::to_integral(packed.back()));
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packed[static_cast<size_type>(entt)] = packed.back();
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// unnecessary but it helps to detect nasty bugs
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ENTT_ASSERT((packed.back() = tombstone, true), "");
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// lazy self-assignment guard
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self = null;
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packed.pop_back();
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}
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}
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/**
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* @brief Erases entities from a sparse set.
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* @param first An iterator to the first element of the range of entities.
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* @param last An iterator past the last element of the range of entities.
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*/
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virtual void in_place_pop(basic_iterator first, basic_iterator last) {
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for(; first != last; ++first) {
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const auto entt = entity_traits::to_entity(std::exchange(sparse_ref(*first), null));
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packed[static_cast<size_type>(entt)] = std::exchange(free_list, entity_traits::combine(entt, entity_traits::reserved));
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}
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}
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/**
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* @brief Assigns an entity to a sparse set.
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* @param entt A valid identifier.
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* @param force_back Force back insertion.
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* @return Iterator pointing to the emplaced element.
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*/
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virtual basic_iterator try_emplace(const Entity entt, const bool force_back, const void * = nullptr) {
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ENTT_ASSERT(!contains(entt), "Set already contains entity");
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if(auto &elem = assure_at_least(entt); free_list == null || force_back) {
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packed.push_back(entt);
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elem = entity_traits::combine(static_cast<typename entity_traits::entity_type>(packed.size() - 1u), entity_traits::to_integral(entt));
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return begin();
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} else {
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const auto pos = static_cast<size_type>(entity_traits::to_entity(free_list));
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elem = entity_traits::combine(entity_traits::to_integral(free_list), entity_traits::to_integral(entt));
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free_list = std::exchange(packed[pos], entt);
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return --(end() - pos);
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}
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}
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public:
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/*! @brief Allocator type. */
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using allocator_type = Allocator;
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/*! @brief Underlying entity identifier. */
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using entity_type = Entity;
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/*! @brief Underlying version type. */
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using version_type = typename entity_traits::version_type;
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/*! @brief Unsigned integer type. */
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using size_type = typename packed_container_type::size_type;
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/*! @brief Pointer type to contained entities. */
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using pointer = typename packed_container_type::const_pointer;
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/*! @brief Random access iterator type. */
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using iterator = basic_iterator;
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/*! @brief Constant random access iterator type. */
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using const_iterator = iterator;
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/*! @brief Reverse iterator type. */
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using reverse_iterator = std::reverse_iterator<iterator>;
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/*! @brief Constant reverse iterator type. */
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using const_reverse_iterator = reverse_iterator;
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/*! @brief Default constructor. */
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basic_sparse_set()
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: basic_sparse_set{type_id<void>()} {}
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/**
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* @brief Constructs an empty container with a given allocator.
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* @param allocator The allocator to use.
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*/
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explicit basic_sparse_set(const allocator_type &allocator)
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: basic_sparse_set{type_id<void>(), deletion_policy::swap_and_pop, allocator} {}
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/**
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* @brief Constructs an empty container with the given policy and allocator.
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* @param pol Type of deletion policy.
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* @param allocator The allocator to use (possibly default-constructed).
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*/
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explicit basic_sparse_set(deletion_policy pol, const allocator_type &allocator = {})
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: basic_sparse_set{type_id<void>(), pol, allocator} {}
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/**
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* @brief Constructs an empty container with the given value type, policy
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* and allocator.
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* @param value Returned value type, if any.
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* @param pol Type of deletion policy.
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* @param allocator The allocator to use (possibly default-constructed).
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*/
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explicit basic_sparse_set(const type_info &value, deletion_policy pol = deletion_policy::swap_and_pop, const allocator_type &allocator = {})
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: sparse{allocator},
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packed{allocator},
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info{&value},
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free_list{tombstone},
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mode{pol} {}
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/**
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* @brief Move constructor.
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* @param other The instance to move from.
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*/
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basic_sparse_set(basic_sparse_set &&other) ENTT_NOEXCEPT
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: sparse{std::move(other.sparse)},
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packed{std::move(other.packed)},
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info{other.info},
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free_list{std::exchange(other.free_list, tombstone)},
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mode{other.mode} {}
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/**
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* @brief Allocator-extended move constructor.
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* @param other The instance to move from.
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* @param allocator The allocator to use.
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*/
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basic_sparse_set(basic_sparse_set &&other, const allocator_type &allocator) ENTT_NOEXCEPT
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: sparse{std::move(other.sparse), allocator},
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packed{std::move(other.packed), allocator},
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info{other.info},
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free_list{std::exchange(other.free_list, tombstone)},
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mode{other.mode} {
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ENTT_ASSERT(alloc_traits::is_always_equal::value || packed.get_allocator() == other.packed.get_allocator(), "Copying a sparse set is not allowed");
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}
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/*! @brief Default destructor. */
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virtual ~basic_sparse_set() {
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release_sparse_pages();
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}
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/**
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* @brief Move assignment operator.
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* @param other The instance to move from.
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* @return This sparse set.
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*/
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basic_sparse_set &operator=(basic_sparse_set &&other) ENTT_NOEXCEPT {
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ENTT_ASSERT(alloc_traits::is_always_equal::value || packed.get_allocator() == other.packed.get_allocator(), "Copying a sparse set is not allowed");
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release_sparse_pages();
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sparse = std::move(other.sparse);
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packed = std::move(other.packed);
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info = other.info;
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free_list = std::exchange(other.free_list, tombstone);
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mode = other.mode;
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return *this;
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}
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/**
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* @brief Exchanges the contents with those of a given sparse set.
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* @param other Sparse set to exchange the content with.
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*/
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void swap(basic_sparse_set &other) {
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using std::swap;
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swap(sparse, other.sparse);
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swap(packed, other.packed);
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swap(info, other.info);
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swap(free_list, other.free_list);
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swap(mode, other.mode);
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}
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/**
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* @brief Returns the associated allocator.
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* @return The associated allocator.
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*/
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[[nodiscard]] constexpr allocator_type get_allocator() const ENTT_NOEXCEPT {
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return packed.get_allocator();
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}
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/**
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* @brief Returns the deletion policy of a sparse set.
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* @return The deletion policy of the sparse set.
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*/
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[[nodiscard]] deletion_policy policy() const ENTT_NOEXCEPT {
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return mode;
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}
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/**
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* @brief Increases the capacity of a sparse set.
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*
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* If the new capacity is greater than the current capacity, new storage is
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* allocated, otherwise the method does nothing.
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*
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* @param cap Desired capacity.
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*/
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virtual void reserve(const size_type cap) {
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packed.reserve(cap);
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}
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/**
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* @brief Returns the number of elements that a sparse set has currently
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* allocated space for.
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* @return Capacity of the sparse set.
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*/
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[[nodiscard]] virtual size_type capacity() const ENTT_NOEXCEPT {
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return packed.capacity();
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}
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/*! @brief Requests the removal of unused capacity. */
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virtual void shrink_to_fit() {
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packed.shrink_to_fit();
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}
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/**
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* @brief Returns the extent of a sparse set.
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*
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* The extent of a sparse set is also the size of the internal sparse array.
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* There is no guarantee that the internal packed array has the same size.
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* Usually the size of the internal sparse array is equal or greater than
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* the one of the internal packed array.
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*
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* @return Extent of the sparse set.
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*/
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[[nodiscard]] size_type extent() const ENTT_NOEXCEPT {
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return sparse.size() * entity_traits::page_size;
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}
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/**
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* @brief Returns the number of elements in a sparse set.
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*
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* The number of elements is also the size of the internal packed array.
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* There is no guarantee that the internal sparse array has the same size.
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* Usually the size of the internal sparse array is equal or greater than
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* the one of the internal packed array.
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*
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* @return Number of elements.
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*/
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[[nodiscard]] size_type size() const ENTT_NOEXCEPT {
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return packed.size();
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}
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/**
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* @brief Checks whether a sparse set is empty.
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* @return True if the sparse set is empty, false otherwise.
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*/
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[[nodiscard]] bool empty() const ENTT_NOEXCEPT {
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return packed.empty();
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}
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/**
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* @brief Direct access to the internal packed array.
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* @return A pointer to the internal packed array.
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*/
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[[nodiscard]] pointer data() const ENTT_NOEXCEPT {
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return packed.data();
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}
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/**
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* @brief Returns an iterator to the beginning.
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*
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* The returned iterator points to the first entity of the internal packed
|
|
* array. If the sparse set is empty, the returned iterator will be equal to
|
|
* `end()`.
|
|
*
|
|
* @return An iterator to the first entity of the sparse set.
|
|
*/
|
|
[[nodiscard]] const_iterator begin() const ENTT_NOEXCEPT {
|
|
const auto pos = static_cast<typename iterator::difference_type>(packed.size());
|
|
return iterator{packed, pos};
|
|
}
|
|
|
|
/*! @copydoc begin */
|
|
[[nodiscard]] const_iterator cbegin() const ENTT_NOEXCEPT {
|
|
return begin();
|
|
}
|
|
|
|
/**
|
|
* @brief Returns an iterator to the end.
|
|
*
|
|
* The returned iterator points to the element following the last entity in
|
|
* a sparse set. Attempting to dereference the returned iterator results in
|
|
* undefined behavior.
|
|
*
|
|
* @return An iterator to the element following the last entity of a sparse
|
|
* set.
|
|
*/
|
|
[[nodiscard]] iterator end() const ENTT_NOEXCEPT {
|
|
return iterator{packed, {}};
|
|
}
|
|
|
|
/*! @copydoc end */
|
|
[[nodiscard]] const_iterator cend() const ENTT_NOEXCEPT {
|
|
return end();
|
|
}
|
|
|
|
/**
|
|
* @brief Returns a reverse iterator to the beginning.
|
|
*
|
|
* The returned iterator points to the first entity of the reversed internal
|
|
* packed array. If the sparse set is empty, the returned iterator will be
|
|
* equal to `rend()`.
|
|
*
|
|
* @return An iterator to the first entity of the reversed internal packed
|
|
* array.
|
|
*/
|
|
[[nodiscard]] const_reverse_iterator rbegin() const ENTT_NOEXCEPT {
|
|
return std::make_reverse_iterator(end());
|
|
}
|
|
|
|
/*! @copydoc rbegin */
|
|
[[nodiscard]] const_reverse_iterator crbegin() const ENTT_NOEXCEPT {
|
|
return rbegin();
|
|
}
|
|
|
|
/**
|
|
* @brief Returns a reverse iterator to the end.
|
|
*
|
|
* The returned iterator points to the element following the last entity in
|
|
* the reversed sparse set. Attempting to dereference the returned iterator
|
|
* results in undefined behavior.
|
|
*
|
|
* @return An iterator to the element following the last entity of the
|
|
* reversed sparse set.
|
|
*/
|
|
[[nodiscard]] reverse_iterator rend() const ENTT_NOEXCEPT {
|
|
return std::make_reverse_iterator(begin());
|
|
}
|
|
|
|
/*! @copydoc rend */
|
|
[[nodiscard]] const_reverse_iterator crend() const ENTT_NOEXCEPT {
|
|
return rend();
|
|
}
|
|
|
|
/**
|
|
* @brief Finds an entity.
|
|
* @param entt A valid identifier.
|
|
* @return An iterator to the given entity if it's found, past the end
|
|
* iterator otherwise.
|
|
*/
|
|
[[nodiscard]] iterator find(const entity_type entt) const ENTT_NOEXCEPT {
|
|
return contains(entt) ? --(end() - index(entt)) : end();
|
|
}
|
|
|
|
/**
|
|
* @brief Checks if a sparse set contains an entity.
|
|
* @param entt A valid identifier.
|
|
* @return True if the sparse set contains the entity, false otherwise.
|
|
*/
|
|
[[nodiscard]] bool contains(const entity_type entt) const ENTT_NOEXCEPT {
|
|
const auto elem = sparse_ptr(entt);
|
|
constexpr auto cap = entity_traits::to_entity(null);
|
|
// testing versions permits to avoid accessing the packed array
|
|
return elem && (((~cap & entity_traits::to_integral(entt)) ^ entity_traits::to_integral(*elem)) < cap);
|
|
}
|
|
|
|
/**
|
|
* @brief Returns the contained version for an identifier.
|
|
* @param entt A valid identifier.
|
|
* @return The version for the given identifier if present, the tombstone
|
|
* version otherwise.
|
|
*/
|
|
[[nodiscard]] version_type current(const entity_type entt) const ENTT_NOEXCEPT {
|
|
const auto elem = sparse_ptr(entt);
|
|
constexpr auto fallback = entity_traits::to_version(tombstone);
|
|
return elem ? entity_traits::to_version(*elem) : fallback;
|
|
}
|
|
|
|
/**
|
|
* @brief Returns the position of an entity in a sparse set.
|
|
*
|
|
* @warning
|
|
* Attempting to get the position of an entity that doesn't belong to the
|
|
* sparse set results in undefined behavior.
|
|
*
|
|
* @param entt A valid identifier.
|
|
* @return The position of the entity in the sparse set.
|
|
*/
|
|
[[nodiscard]] size_type index(const entity_type entt) const ENTT_NOEXCEPT {
|
|
ENTT_ASSERT(contains(entt), "Set does not contain entity");
|
|
return static_cast<size_type>(entity_traits::to_entity(sparse_ref(entt)));
|
|
}
|
|
|
|
/**
|
|
* @brief Returns the entity at specified location, with bounds checking.
|
|
* @param pos The position for which to return the entity.
|
|
* @return The entity at specified location if any, a null entity otherwise.
|
|
*/
|
|
[[nodiscard]] entity_type at(const size_type pos) const ENTT_NOEXCEPT {
|
|
return pos < packed.size() ? packed[pos] : null;
|
|
}
|
|
|
|
/**
|
|
* @brief Returns the entity at specified location, without bounds checking.
|
|
* @param pos The position for which to return the entity.
|
|
* @return The entity at specified location.
|
|
*/
|
|
[[nodiscard]] entity_type operator[](const size_type pos) const ENTT_NOEXCEPT {
|
|
ENTT_ASSERT(pos < packed.size(), "Position is out of bounds");
|
|
return packed[pos];
|
|
}
|
|
|
|
/**
|
|
* @brief Returns the element assigned to an entity, if any.
|
|
*
|
|
* @warning
|
|
* Attempting to use an entity that doesn't belong to the sparse set results
|
|
* in undefined behavior.
|
|
*
|
|
* @param entt A valid identifier.
|
|
* @return An opaque pointer to the element assigned to the entity, if any.
|
|
*/
|
|
const void *get(const entity_type entt) const ENTT_NOEXCEPT {
|
|
return get_at(index(entt));
|
|
}
|
|
|
|
/*! @copydoc get */
|
|
void *get(const entity_type entt) ENTT_NOEXCEPT {
|
|
return const_cast<void *>(std::as_const(*this).get(entt));
|
|
}
|
|
|
|
/**
|
|
* @brief Assigns an entity to a sparse set.
|
|
*
|
|
* @warning
|
|
* Attempting to assign an entity that already belongs to the sparse set
|
|
* results in undefined behavior.
|
|
*
|
|
* @param entt A valid identifier.
|
|
* @param value Optional opaque value to forward to mixins, if any.
|
|
* @return Iterator pointing to the emplaced element in case of success, the
|
|
* `end()` iterator otherwise.
|
|
*/
|
|
iterator emplace(const entity_type entt, const void *value = nullptr) {
|
|
return try_emplace(entt, false, value);
|
|
}
|
|
|
|
/**
|
|
* @brief Bump the version number of an entity.
|
|
*
|
|
* @warning
|
|
* Attempting to bump the version of an entity that doesn't belong to the
|
|
* sparse set results in undefined behavior.
|
|
*
|
|
* @param entt A valid identifier.
|
|
*/
|
|
void bump(const entity_type entt) {
|
|
auto &entity = sparse_ref(entt);
|
|
entity = entity_traits::combine(entity_traits::to_integral(entity), entity_traits::to_integral(entt));
|
|
packed[static_cast<size_type>(entity_traits::to_entity(entity))] = entt;
|
|
}
|
|
|
|
/**
|
|
* @brief Assigns one or more entities to a sparse set.
|
|
*
|
|
* @warning
|
|
* Attempting to assign an entity that already belongs to the sparse set
|
|
* 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.
|
|
* @return Iterator pointing to the first element inserted in case of
|
|
* success, the `end()` iterator otherwise.
|
|
*/
|
|
template<typename It>
|
|
iterator insert(It first, It last) {
|
|
for(auto it = first; it != last; ++it) {
|
|
try_emplace(*it, true);
|
|
}
|
|
|
|
return first == last ? end() : find(*first);
|
|
}
|
|
|
|
/**
|
|
* @brief Erases an entity from a sparse set.
|
|
*
|
|
* @warning
|
|
* Attempting to erase an entity that doesn't belong to the sparse set
|
|
* results in undefined behavior.
|
|
*
|
|
* @param entt A valid identifier.
|
|
*/
|
|
void erase(const entity_type entt) {
|
|
const auto it = --(end() - index(entt));
|
|
(mode == deletion_policy::in_place) ? in_place_pop(it, it + 1u) : swap_and_pop(it, it + 1u);
|
|
}
|
|
|
|
/**
|
|
* @brief Erases entities from a set.
|
|
*
|
|
* @sa erase
|
|
*
|
|
* @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.
|
|
*/
|
|
template<typename It>
|
|
void erase(It first, It last) {
|
|
if constexpr(std::is_same_v<It, basic_iterator>) {
|
|
(mode == deletion_policy::in_place) ? in_place_pop(first, last) : swap_and_pop(first, last);
|
|
} else {
|
|
for(; first != last; ++first) {
|
|
erase(*first);
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* @brief Removes an entity from a sparse set if it exists.
|
|
* @param entt A valid identifier.
|
|
* @return True if the entity is actually removed, false otherwise.
|
|
*/
|
|
bool remove(const entity_type entt) {
|
|
return contains(entt) && (erase(entt), true);
|
|
}
|
|
|
|
/**
|
|
* @brief Removes entities from a sparse set if they exist.
|
|
* @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.
|
|
* @return The number of entities actually removed.
|
|
*/
|
|
template<typename It>
|
|
size_type remove(It first, It last) {
|
|
size_type count{};
|
|
|
|
for(; first != last; ++first) {
|
|
count += remove(*first);
|
|
}
|
|
|
|
return count;
|
|
}
|
|
|
|
/*! @brief Removes all tombstones from the packed array of a sparse set. */
|
|
void compact() {
|
|
size_type from = packed.size();
|
|
for(; from && packed[from - 1u] == tombstone; --from) {}
|
|
|
|
for(auto *it = &free_list; *it != null && from; it = std::addressof(packed[entity_traits::to_entity(*it)])) {
|
|
if(const size_type to = entity_traits::to_entity(*it); to < from) {
|
|
--from;
|
|
move_element(from, to);
|
|
|
|
using std::swap;
|
|
swap(packed[from], packed[to]);
|
|
|
|
const auto entity = static_cast<typename entity_traits::entity_type>(to);
|
|
sparse_ref(packed[to]) = entity_traits::combine(entity, entity_traits::to_integral(packed[to]));
|
|
*it = entity_traits::combine(static_cast<typename entity_traits::entity_type>(from), entity_traits::reserved);
|
|
for(; from && packed[from - 1u] == tombstone; --from) {}
|
|
}
|
|
}
|
|
|
|
free_list = tombstone;
|
|
packed.resize(from);
|
|
}
|
|
|
|
/**
|
|
* @brief Swaps two entities in a sparse set.
|
|
*
|
|
* For what it's worth, this function affects both the internal sparse array
|
|
* and the internal packed array. Users should not care of that anyway.
|
|
*
|
|
* @warning
|
|
* Attempting to swap entities that don't belong to the sparse set results
|
|
* in undefined behavior.
|
|
*
|
|
* @param lhs A valid identifier.
|
|
* @param rhs A valid identifier.
|
|
*/
|
|
void swap_elements(const entity_type lhs, const entity_type rhs) {
|
|
ENTT_ASSERT(contains(lhs) && contains(rhs), "Set does not contain entities");
|
|
|
|
auto &entt = sparse_ref(lhs);
|
|
auto &other = sparse_ref(rhs);
|
|
|
|
const auto from = entity_traits::to_entity(entt);
|
|
const auto to = entity_traits::to_entity(other);
|
|
|
|
// basic no-leak guarantee (with invalid state) if swapping throws
|
|
swap_at(static_cast<size_type>(from), static_cast<size_type>(to));
|
|
entt = entity_traits::combine(to, entity_traits::to_integral(packed[from]));
|
|
other = entity_traits::combine(from, entity_traits::to_integral(packed[to]));
|
|
|
|
using std::swap;
|
|
swap(packed[from], packed[to]);
|
|
}
|
|
|
|
/**
|
|
* @brief Sort the first count elements according to the given comparison
|
|
* function.
|
|
*
|
|
* The comparison function object must return `true` if the first element
|
|
* is _less_ than the second one, `false` otherwise. The signature of the
|
|
* comparison function should be equivalent to the following:
|
|
*
|
|
* @code{.cpp}
|
|
* bool(const Entity, const Entity);
|
|
* @endcode
|
|
*
|
|
* Moreover, the comparison function object shall induce a
|
|
* _strict weak ordering_ on the values.
|
|
*
|
|
* The sort function object must offer a member function template
|
|
* `operator()` that accepts three arguments:
|
|
*
|
|
* * An iterator to the first element of the range to sort.
|
|
* * An iterator past the last element of the range to sort.
|
|
* * A comparison function to use to compare the elements.
|
|
*
|
|
* @tparam Compare Type of comparison function object.
|
|
* @tparam Sort Type of sort function object.
|
|
* @tparam Args Types of arguments to forward to the sort function object.
|
|
* @param length Number of elements to sort.
|
|
* @param compare A valid comparison function object.
|
|
* @param algo A valid sort function object.
|
|
* @param args Arguments to forward to the sort function object, if any.
|
|
*/
|
|
template<typename Compare, typename Sort = std_sort, typename... Args>
|
|
void sort_n(const size_type length, Compare compare, Sort algo = Sort{}, Args &&...args) {
|
|
ENTT_ASSERT(!(length > packed.size()), "Length exceeds the number of elements");
|
|
ENTT_ASSERT(free_list == null, "Partial sorting with tombstones is not supported");
|
|
|
|
algo(packed.rend() - length, packed.rend(), std::move(compare), std::forward<Args>(args)...);
|
|
|
|
for(size_type pos{}; pos < length; ++pos) {
|
|
auto curr = pos;
|
|
auto next = index(packed[curr]);
|
|
|
|
while(curr != next) {
|
|
const auto idx = index(packed[next]);
|
|
const auto entt = packed[curr];
|
|
|
|
swap_at(next, idx);
|
|
const auto entity = static_cast<typename entity_traits::entity_type>(curr);
|
|
sparse_ref(entt) = entity_traits::combine(entity, entity_traits::to_integral(packed[curr]));
|
|
curr = std::exchange(next, idx);
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* @brief Sort all elements according to the given comparison function.
|
|
*
|
|
* @sa sort_n
|
|
*
|
|
* @tparam Compare Type of comparison function object.
|
|
* @tparam Sort Type of sort function object.
|
|
* @tparam Args Types of arguments to forward to the sort function object.
|
|
* @param compare A valid comparison function object.
|
|
* @param algo A valid sort function object.
|
|
* @param args Arguments to forward to the sort function object, if any.
|
|
*/
|
|
template<typename Compare, typename Sort = std_sort, typename... Args>
|
|
void sort(Compare compare, Sort algo = Sort{}, Args &&...args) {
|
|
compact();
|
|
sort_n(packed.size(), std::move(compare), std::move(algo), std::forward<Args>(args)...);
|
|
}
|
|
|
|
/**
|
|
* @brief Sort entities according to their order in another sparse set.
|
|
*
|
|
* Entities that are part of both the sparse sets are ordered internally
|
|
* according to the order they have in `other`. All the other entities goes
|
|
* to the end of the list and there are no guarantees on their order.<br/>
|
|
* In other terms, this function can be used to impose the same order on two
|
|
* sets by using one of them as a master and the other one as a slave.
|
|
*
|
|
* Iterating the sparse set with a couple of iterators returns elements in
|
|
* the expected order after a call to `respect`. See `begin` and `end` for
|
|
* more details.
|
|
*
|
|
* @param other The sparse sets that imposes the order of the entities.
|
|
*/
|
|
void respect(const basic_sparse_set &other) {
|
|
compact();
|
|
|
|
const auto to = other.end();
|
|
auto from = other.begin();
|
|
|
|
for(size_type pos = packed.size() - 1; pos && from != to; ++from) {
|
|
if(contains(*from)) {
|
|
if(*from != packed[pos]) {
|
|
// basic no-leak guarantee (with invalid state) if swapping throws
|
|
swap_elements(packed[pos], *from);
|
|
}
|
|
|
|
--pos;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*! @brief Clears a sparse set. */
|
|
void clear() {
|
|
if(const auto last = end(); free_list == null) {
|
|
in_place_pop(begin(), last);
|
|
} else {
|
|
for(auto &&entity: *this) {
|
|
// tombstone filter on itself
|
|
if(const auto it = find(entity); it != last) {
|
|
in_place_pop(it, it + 1u);
|
|
}
|
|
}
|
|
}
|
|
|
|
free_list = tombstone;
|
|
packed.clear();
|
|
}
|
|
|
|
/**
|
|
* @brief Returned value type, if any.
|
|
* @return Returned value type, if any.
|
|
*/
|
|
const type_info &type() const ENTT_NOEXCEPT {
|
|
return *info;
|
|
}
|
|
|
|
/*! @brief Forwards variables to mixins, if any. */
|
|
virtual void bind(any) ENTT_NOEXCEPT {}
|
|
|
|
private:
|
|
sparse_container_type sparse;
|
|
packed_container_type packed;
|
|
const type_info *info;
|
|
entity_type free_list;
|
|
deletion_policy mode;
|
|
};
|
|
|
|
} // namespace entt
|
|
|
|
#endif
|