🛠️🐜 Antkeeper superbuild with dependencies included
https://antkeeper.com
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
535 lines
17 KiB
535 lines
17 KiB
#ifndef ENTT_ENTITY_SPARSE_SET_HPP
|
|
#define ENTT_ENTITY_SPARSE_SET_HPP
|
|
|
|
|
|
#include <algorithm>
|
|
#include <iterator>
|
|
#include <utility>
|
|
#include <vector>
|
|
#include <memory>
|
|
#include <cstddef>
|
|
#include "../config/config.h"
|
|
#include "entity.hpp"
|
|
|
|
|
|
namespace entt {
|
|
|
|
|
|
/**
|
|
* @brief Basic sparse set implementation.
|
|
*
|
|
* Sparse set or packed array or whatever is the name users give it.<br/>
|
|
* Two arrays: an _external_ one and an _internal_ one; a _sparse_ one and a
|
|
* _packed_ one; one used for direct access through contiguous memory, the other
|
|
* one used to get the data through an extra level of indirection.<br/>
|
|
* This is largely used by the registry to offer users the fastest access ever
|
|
* to the components. Views and groups in general are almost entirely designed
|
|
* around sparse sets.
|
|
*
|
|
* This type of data structure is widely documented in the literature and on the
|
|
* web. This is nothing more than a customized implementation suitable for the
|
|
* purpose of the framework.
|
|
*
|
|
* @note
|
|
* There are no guarantees that entities are returned in the insertion order
|
|
* when iterate a sparse set. Do not make assumption on the order in any case.
|
|
*
|
|
* @note
|
|
* Internal data structures arrange elements to maximize performance. Because of
|
|
* that, there are no guarantees that elements have the expected order when
|
|
* iterate directly the internal packed array (see `data` and `size` member
|
|
* functions for that). Use `begin` and `end` instead.
|
|
*
|
|
* @tparam Entity A valid entity type (see entt_traits for more details).
|
|
*/
|
|
template<typename Entity>
|
|
class sparse_set {
|
|
using traits_type = entt_traits<Entity>;
|
|
|
|
static_assert(ENTT_PAGE_SIZE && ((ENTT_PAGE_SIZE & (ENTT_PAGE_SIZE - 1)) == 0));
|
|
static constexpr auto entt_per_page = ENTT_PAGE_SIZE / sizeof(typename entt_traits<Entity>::entity_type);
|
|
|
|
class iterator {
|
|
friend class sparse_set<Entity>;
|
|
|
|
using direct_type = const std::vector<Entity>;
|
|
using index_type = typename traits_type::difference_type;
|
|
|
|
iterator(direct_type *ref, const index_type idx) ENTT_NOEXCEPT
|
|
: direct{ref}, index{idx}
|
|
{}
|
|
|
|
public:
|
|
using difference_type = index_type;
|
|
using value_type = Entity;
|
|
using pointer = const value_type *;
|
|
using reference = const value_type &;
|
|
using iterator_category = std::random_access_iterator_tag;
|
|
|
|
iterator() ENTT_NOEXCEPT = default;
|
|
|
|
iterator & operator++() ENTT_NOEXCEPT {
|
|
return --index, *this;
|
|
}
|
|
|
|
iterator operator++(int) ENTT_NOEXCEPT {
|
|
iterator orig = *this;
|
|
return ++(*this), orig;
|
|
}
|
|
|
|
iterator & operator--() ENTT_NOEXCEPT {
|
|
return ++index, *this;
|
|
}
|
|
|
|
iterator operator--(int) ENTT_NOEXCEPT {
|
|
iterator orig = *this;
|
|
return --(*this), orig;
|
|
}
|
|
|
|
iterator & operator+=(const difference_type value) ENTT_NOEXCEPT {
|
|
index -= value;
|
|
return *this;
|
|
}
|
|
|
|
iterator operator+(const difference_type value) const ENTT_NOEXCEPT {
|
|
return iterator{direct, index-value};
|
|
}
|
|
|
|
inline iterator & operator-=(const difference_type value) ENTT_NOEXCEPT {
|
|
return (*this += -value);
|
|
}
|
|
|
|
inline iterator operator-(const difference_type value) const ENTT_NOEXCEPT {
|
|
return (*this + -value);
|
|
}
|
|
|
|
difference_type operator-(const iterator &other) const ENTT_NOEXCEPT {
|
|
return other.index - index;
|
|
}
|
|
|
|
reference operator[](const difference_type value) const ENTT_NOEXCEPT {
|
|
const auto pos = size_type(index-value-1);
|
|
return (*direct)[pos];
|
|
}
|
|
|
|
bool operator==(const iterator &other) const ENTT_NOEXCEPT {
|
|
return other.index == index;
|
|
}
|
|
|
|
inline bool operator!=(const iterator &other) const ENTT_NOEXCEPT {
|
|
return !(*this == other);
|
|
}
|
|
|
|
bool operator<(const iterator &other) const ENTT_NOEXCEPT {
|
|
return index > other.index;
|
|
}
|
|
|
|
bool operator>(const iterator &other) const ENTT_NOEXCEPT {
|
|
return index < other.index;
|
|
}
|
|
|
|
inline bool operator<=(const iterator &other) const ENTT_NOEXCEPT {
|
|
return !(*this > other);
|
|
}
|
|
|
|
inline bool operator>=(const iterator &other) const ENTT_NOEXCEPT {
|
|
return !(*this < other);
|
|
}
|
|
|
|
pointer operator->() const ENTT_NOEXCEPT {
|
|
const auto pos = size_type(index-1);
|
|
return &(*direct)[pos];
|
|
}
|
|
|
|
inline reference operator*() const ENTT_NOEXCEPT {
|
|
return *operator->();
|
|
}
|
|
|
|
private:
|
|
direct_type *direct;
|
|
index_type index;
|
|
};
|
|
|
|
void assure(const std::size_t page) {
|
|
if(!(page < reverse.size())) {
|
|
reverse.resize(page+1);
|
|
}
|
|
|
|
if(!reverse[page].first) {
|
|
reverse[page].first = std::make_unique<entity_type[]>(entt_per_page);
|
|
// null is safe in all cases for our purposes
|
|
std::fill_n(reverse[page].first.get(), entt_per_page, null);
|
|
}
|
|
}
|
|
|
|
auto index(const Entity entt) const ENTT_NOEXCEPT {
|
|
const auto identifier = entt & traits_type::entity_mask;
|
|
const auto page = size_type(identifier / entt_per_page);
|
|
const auto offset = size_type(identifier & (entt_per_page - 1));
|
|
return std::make_pair(page, offset);
|
|
}
|
|
|
|
public:
|
|
/*! @brief Underlying entity identifier. */
|
|
using entity_type = Entity;
|
|
/*! @brief Unsigned integer type. */
|
|
using size_type = std::size_t;
|
|
/*! @brief Random access iterator type. */
|
|
using iterator_type = iterator;
|
|
|
|
/*! @brief Default constructor. */
|
|
sparse_set() = default;
|
|
|
|
/**
|
|
* @brief Copy constructor.
|
|
* @param other The instance to copy from.
|
|
*/
|
|
sparse_set(const sparse_set &other)
|
|
: reverse{},
|
|
direct{other.direct}
|
|
{
|
|
for(size_type pos{}, last = other.reverse.size(); pos < last; ++pos) {
|
|
if(other.reverse[pos].first) {
|
|
assure(pos);
|
|
std::copy_n(other.reverse[pos].first.get(), entt_per_page, reverse[pos].first.get());
|
|
reverse[pos].second = other.reverse[pos].second;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*! @brief Default move constructor. */
|
|
sparse_set(sparse_set &&) = default;
|
|
|
|
/*! @brief Default destructor. */
|
|
virtual ~sparse_set() ENTT_NOEXCEPT = default;
|
|
|
|
/**
|
|
* @brief Copy assignment operator.
|
|
* @param other The instance to copy from.
|
|
* @return This sparse set.
|
|
*/
|
|
sparse_set & operator=(const sparse_set &other) {
|
|
if(&other != this) {
|
|
auto tmp{other};
|
|
*this = std::move(tmp);
|
|
}
|
|
|
|
return *this;
|
|
}
|
|
|
|
/*! @brief Default move assignment operator. @return This sparse set. */
|
|
sparse_set & operator=(sparse_set &&) = default;
|
|
|
|
/**
|
|
* @brief Increases the capacity of a sparse set.
|
|
*
|
|
* If the new capacity is greater than the current capacity, new storage is
|
|
* allocated, otherwise the method does nothing.
|
|
*
|
|
* @param cap Desired capacity.
|
|
*/
|
|
virtual void reserve(const size_type cap) {
|
|
direct.reserve(cap);
|
|
}
|
|
|
|
/**
|
|
* @brief Returns the number of elements that a sparse set has currently
|
|
* allocated space for.
|
|
* @return Capacity of the sparse set.
|
|
*/
|
|
size_type capacity() const ENTT_NOEXCEPT {
|
|
return direct.capacity();
|
|
}
|
|
|
|
/*! @brief Requests the removal of unused capacity. */
|
|
virtual void shrink_to_fit() {
|
|
while(!reverse.empty() && !reverse.back().second) {
|
|
reverse.pop_back();
|
|
}
|
|
|
|
for(auto &&data: reverse) {
|
|
if(!data.second) {
|
|
data.first.reset();
|
|
}
|
|
}
|
|
|
|
reverse.shrink_to_fit();
|
|
direct.shrink_to_fit();
|
|
}
|
|
|
|
/**
|
|
* @brief Returns the extent of a sparse set.
|
|
*
|
|
* The extent of a sparse set is also the size of the internal sparse array.
|
|
* There is no guarantee that the internal packed array has the same size.
|
|
* Usually the size of the internal sparse array is equal or greater than
|
|
* the one of the internal packed array.
|
|
*
|
|
* @return Extent of the sparse set.
|
|
*/
|
|
size_type extent() const ENTT_NOEXCEPT {
|
|
return reverse.size() * entt_per_page;
|
|
}
|
|
|
|
/**
|
|
* @brief Returns the number of elements in a sparse set.
|
|
*
|
|
* The number of elements is also the size of the internal packed array.
|
|
* There is no guarantee that the internal sparse array has the same size.
|
|
* Usually the size of the internal sparse array is equal or greater than
|
|
* the one of the internal packed array.
|
|
*
|
|
* @return Number of elements.
|
|
*/
|
|
size_type size() const ENTT_NOEXCEPT {
|
|
return direct.size();
|
|
}
|
|
|
|
/**
|
|
* @brief Checks whether a sparse set is empty.
|
|
* @return True if the sparse set is empty, false otherwise.
|
|
*/
|
|
bool empty() const ENTT_NOEXCEPT {
|
|
return direct.empty();
|
|
}
|
|
|
|
/**
|
|
* @brief Direct access to the internal packed array.
|
|
*
|
|
* The returned pointer is such that range `[data(), data() + size()]` is
|
|
* always a valid range, even if the container is empty.
|
|
*
|
|
* @note
|
|
* There are no guarantees on the order, even though `respect` has been
|
|
* previously invoked. Internal data structures arrange elements to maximize
|
|
* performance. Accessing them directly gives a performance boost but less
|
|
* guarantees. Use `begin` and `end` if you want to iterate the sparse set
|
|
* in the expected order.
|
|
*
|
|
* @return A pointer to the internal packed array.
|
|
*/
|
|
const entity_type * data() const ENTT_NOEXCEPT {
|
|
return direct.data();
|
|
}
|
|
|
|
/**
|
|
* @brief Returns an iterator to the beginning.
|
|
*
|
|
* 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()`.
|
|
*
|
|
* @note
|
|
* Input iterators stay true to the order imposed by a call to `respect`.
|
|
*
|
|
* @return An iterator to the first entity of the internal packed array.
|
|
*/
|
|
iterator_type begin() const ENTT_NOEXCEPT {
|
|
const typename traits_type::difference_type pos = direct.size();
|
|
return iterator_type{&direct, pos};
|
|
}
|
|
|
|
/**
|
|
* @brief Returns an iterator to the end.
|
|
*
|
|
* The returned iterator points to the element following the last entity in
|
|
* the internal packed array. Attempting to dereference the returned
|
|
* iterator results in undefined behavior.
|
|
*
|
|
* @note
|
|
* Input iterators stay true to the order imposed by a call to `respect`.
|
|
*
|
|
* @return An iterator to the element following the last entity of the
|
|
* internal packed array.
|
|
*/
|
|
iterator_type end() const ENTT_NOEXCEPT {
|
|
return iterator_type{&direct, {}};
|
|
}
|
|
|
|
/**
|
|
* @brief Finds an entity.
|
|
* @param entt A valid entity identifier.
|
|
* @return An iterator to the given entity if it's found, past the end
|
|
* iterator otherwise.
|
|
*/
|
|
iterator_type find(const entity_type entt) const ENTT_NOEXCEPT {
|
|
return has(entt) ? --(end() - get(entt)) : end();
|
|
}
|
|
|
|
/**
|
|
* @brief Checks if a sparse set contains an entity.
|
|
* @param entt A valid entity identifier.
|
|
* @return True if the sparse set contains the entity, false otherwise.
|
|
*/
|
|
bool has(const entity_type entt) const ENTT_NOEXCEPT {
|
|
auto [page, offset] = index(entt);
|
|
// testing against null permits to avoid accessing the direct vector
|
|
return (page < reverse.size() && reverse[page].second && reverse[page].first[offset] != null);
|
|
}
|
|
|
|
/**
|
|
* @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.<br/>
|
|
* An assertion will abort the execution at runtime in debug mode if the
|
|
* sparse set doesn't contain the given entity.
|
|
*
|
|
* @param entt A valid entity identifier.
|
|
* @return The position of the entity in the sparse set.
|
|
*/
|
|
size_type get(const entity_type entt) const ENTT_NOEXCEPT {
|
|
ENTT_ASSERT(has(entt));
|
|
auto [page, offset] = index(entt);
|
|
return size_type(reverse[page].first[offset]);
|
|
}
|
|
|
|
/**
|
|
* @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.<br/>
|
|
* An assertion will abort the execution at runtime in debug mode if the
|
|
* sparse set already contains the given entity.
|
|
*
|
|
* @param entt A valid entity identifier.
|
|
*/
|
|
void construct(const entity_type entt) {
|
|
ENTT_ASSERT(!has(entt));
|
|
auto [page, offset] = index(entt);
|
|
assure(page);
|
|
reverse[page].first[offset] = entity_type(direct.size());
|
|
reverse[page].second++;
|
|
direct.push_back(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.<br/>
|
|
* An assertion will abort the execution at runtime in debug mode if the
|
|
* sparse set already contains the given entity.
|
|
*
|
|
* @tparam It Type of forward 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 batch(It first, It last) {
|
|
std::for_each(first, last, [next = entity_type(direct.size()), this](const auto entt) mutable {
|
|
ENTT_ASSERT(!has(entt));
|
|
auto [page, offset] = index(entt);
|
|
assure(page);
|
|
reverse[page].first[offset] = next++;
|
|
reverse[page].second++;
|
|
});
|
|
|
|
direct.insert(direct.end(), first, last);
|
|
}
|
|
|
|
/**
|
|
* @brief Removes an entity from a sparse set.
|
|
*
|
|
* @warning
|
|
* Attempting to remove an entity that doesn't belong to the sparse set
|
|
* results in undefined behavior.<br/>
|
|
* An assertion will abort the execution at runtime in debug mode if the
|
|
* sparse set doesn't contain the given entity.
|
|
*
|
|
* @param entt A valid entity identifier.
|
|
*/
|
|
virtual void destroy(const entity_type entt) {
|
|
ENTT_ASSERT(has(entt));
|
|
auto [from_page, from_offset] = index(entt);
|
|
auto [to_page, to_offset] = index(direct.back());
|
|
direct[size_type(reverse[from_page].first[from_offset])] = direct.back();
|
|
reverse[to_page].first[to_offset] = reverse[from_page].first[from_offset];
|
|
reverse[from_page].first[from_offset] = null;
|
|
reverse[from_page].second--;
|
|
direct.pop_back();
|
|
}
|
|
|
|
/**
|
|
* @brief Swaps two entities in the internal packed array.
|
|
*
|
|
* 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.<br/>
|
|
* An assertion will abort the execution at runtime in debug mode if the
|
|
* sparse set doesn't contain the given entities.
|
|
*
|
|
* @param lhs A valid position within the sparse set.
|
|
* @param rhs A valid position within the sparse set.
|
|
*/
|
|
void swap(const size_type lhs, const size_type rhs) ENTT_NOEXCEPT {
|
|
ENTT_ASSERT(lhs < direct.size());
|
|
ENTT_ASSERT(rhs < direct.size());
|
|
auto [src_page, src_offset] = index(direct[lhs]);
|
|
auto [dst_page, dst_offset] = index(direct[rhs]);
|
|
std::swap(reverse[src_page].first[src_offset], reverse[dst_page].first[dst_offset]);
|
|
std::swap(direct[lhs], direct[rhs]);
|
|
}
|
|
|
|
/**
|
|
* @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 guarantess 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.
|
|
*
|
|
* @note
|
|
* Attempting to iterate elements using the raw pointer returned by `data`
|
|
* gives no guarantees on the order, even though `respect` has been invoked.
|
|
*
|
|
* @param other The sparse sets that imposes the order of the entities.
|
|
*/
|
|
virtual void respect(const sparse_set &other) ENTT_NOEXCEPT {
|
|
const auto to = other.end();
|
|
auto from = other.begin();
|
|
|
|
size_type pos = direct.size() - 1;
|
|
|
|
while(pos && from != to) {
|
|
if(has(*from)) {
|
|
if(*from != direct[pos]) {
|
|
swap(pos, get(*from));
|
|
}
|
|
|
|
--pos;
|
|
}
|
|
|
|
++from;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* @brief Resets a sparse set.
|
|
*/
|
|
virtual void reset() {
|
|
reverse.clear();
|
|
direct.clear();
|
|
}
|
|
|
|
private:
|
|
std::vector<std::pair<std::unique_ptr<entity_type[]>, size_type>> reverse;
|
|
std::vector<entity_type> direct;
|
|
};
|
|
|
|
|
|
}
|
|
|
|
|
|
#endif // ENTT_ENTITY_SPARSE_SET_HPP
|