build: add entt library

include/entt/container/table.hpp

@@ -0,0 +1,434 @@
+#ifndef ENTT_CONTAINER_TABLE_HPP
+#define ENTT_CONTAINER_TABLE_HPP
+
+#include "../config/config.h"
+#include "../core/iterator.hpp"
+#include "../stl/concepts.hpp"
+#include "../stl/cstddef.hpp"
+#include "../stl/iterator.hpp"
+#include "../stl/tuple.hpp"
+#include "../stl/utility.hpp"
+#include "fwd.hpp"
+
+namespace entt {
+
+/*! @cond ENTT_INTERNAL */
+namespace internal {
+
+template<typename... It>
+class table_iterator {
+    template<typename...>
+    friend class table_iterator;
+
+public:
+    using value_type = decltype(stl::forward_as_tuple(*stl::declval<It>()...));
+    using pointer = input_iterator_pointer<value_type>;
+    using reference = value_type;
+    using difference_type = stl::ptrdiff_t;
+    using iterator_category = stl::input_iterator_tag;
+    using iterator_concept = stl::random_access_iterator_tag;
+
+    constexpr table_iterator() noexcept
+        : it{} {}
+
+    constexpr table_iterator(It... from) noexcept
+        : it{from...} {}
+
+    template<typename... Other>
+    requires (stl::constructible_from<It, Other> && ...)
+    constexpr table_iterator(const table_iterator<Other...> &other) noexcept
+        : table_iterator{stl::get<Other>(other.it)...} {}
+
+    constexpr table_iterator &operator++() noexcept {
+        return (++stl::get<It>(it), ...), *this;
+    }
+
+    constexpr table_iterator operator++(int) noexcept {
+        const table_iterator orig = *this;
+        return ++(*this), orig;
+    }
+
+    constexpr table_iterator &operator--() noexcept {
+        return (--stl::get<It>(it), ...), *this;
+    }
+
+    constexpr table_iterator operator--(int) noexcept {
+        const table_iterator orig = *this;
+        return operator--(), orig;
+    }
+
+    constexpr table_iterator &operator+=(const difference_type value) noexcept {
+        return ((stl::get<It>(it) += value), ...), *this;
+    }
+
+    constexpr table_iterator operator+(const difference_type value) const noexcept {
+        table_iterator copy = *this;
+        return (copy += value);
+    }
+
+    constexpr table_iterator &operator-=(const difference_type value) noexcept {
+        return (*this += -value);
+    }
+
+    constexpr table_iterator operator-(const difference_type value) const noexcept {
+        return (*this + -value);
+    }
+
+    [[nodiscard]] constexpr reference operator[](const difference_type value) const noexcept {
+        return stl::forward_as_tuple(stl::get<It>(it)[value]...);
+    }
+
+    [[nodiscard]] constexpr pointer operator->() const noexcept {
+        return {operator[](0)};
+    }
+
+    [[nodiscard]] constexpr reference operator*() const noexcept {
+        return operator[](0);
+    }
+
+    template<typename... Other>
+    [[nodiscard]] constexpr stl::ptrdiff_t operator-(const table_iterator<Other...> &other) const noexcept {
+        return stl::get<0>(it) - stl::get<0>(other.it);
+    }
+
+    template<typename... Other>
+    [[nodiscard]] constexpr bool operator==(const table_iterator<Other...> &other) const noexcept {
+        return stl::get<0>(it) == stl::get<0>(other.it);
+    }
+
+    template<typename... Other>
+    [[nodiscard]] constexpr auto operator<=>(const table_iterator<Other...> &other) const noexcept {
+        return stl::get<0>(it) <=> stl::get<0>(other.it);
+    }
+
+private:
+    stl::tuple<It...> it;
+};
+
+} // namespace internal
+/*! @endcond */
+
+/**
+ * @brief Basic table implementation.
+ *
+ * Internal data structures arrange elements to maximize performance. There are
+ * no guarantees that objects are returned in the insertion order when iterate
+ * a table. Do not make assumption on the order in any case.
+ *
+ * @tparam Container Sequence container row types.
+ */
+template<typename... Container>
+class basic_table {
+    using container_type = stl::tuple<Container...>;
+
+public:
+    /*! @brief Unsigned integer type. */
+    using size_type = stl::size_t;
+    /*! @brief Signed integer type. */
+    using difference_type = stl::ptrdiff_t;
+    /*! @brief Input iterator type. */
+    using iterator = internal::table_iterator<typename Container::iterator...>;
+    /*! @brief Constant input iterator type. */
+    using const_iterator = internal::table_iterator<typename Container::const_iterator...>;
+    /*! @brief Reverse iterator type. */
+    using reverse_iterator = internal::table_iterator<typename Container::reverse_iterator...>;
+    /*! @brief Constant reverse iterator type. */
+    using const_reverse_iterator = internal::table_iterator<typename Container::const_reverse_iterator...>;
+
+    /*! @brief Default constructor. */
+    basic_table()
+        : payload{} {
+    }
+
+    /**
+     * @brief Copy constructs the underlying containers.
+     * @param container The containers to copy from.
+     */
+    explicit basic_table(const Container &...container) noexcept
+        : payload{container...} {
+        ENTT_ASSERT((((stl::get<Container>(payload).size() * sizeof...(Container)) == (stl::get<Container>(payload).size() + ...)) && ...), "Unexpected container size");
+    }
+
+    /**
+     * @brief Move constructs the underlying containers.
+     * @param container The containers to move from.
+     */
+    explicit basic_table(Container &&...container) noexcept
+        : payload{stl::move(container)...} {
+        ENTT_ASSERT((((stl::get<Container>(payload).size() * sizeof...(Container)) == (stl::get<Container>(payload).size() + ...)) && ...), "Unexpected container size");
+    }
+
+    /*! @brief Default copy constructor, deleted on purpose. */
+    basic_table(const basic_table &) = delete;
+
+    /**
+     * @brief Move constructor.
+     * @param other The instance to move from.
+     */
+    basic_table(basic_table &&other) noexcept
+        : payload{stl::move(other.payload)} {}
+
+    /**
+     * @brief Constructs the underlying containers using a given allocator.
+     * @param allocator A valid allocator.
+     */
+    explicit basic_table(const auto &allocator)
+        : payload{Container{allocator}...} {}
+
+    /**
+     * @brief Copy constructs the underlying containers using a given allocator.
+     * @tparam Allocator Type of allocator.
+     * @param container The containers to copy from.
+     * @param allocator A valid allocator.
+     */
+    template<class Allocator>
+    basic_table(const Container &...container, const Allocator &allocator) noexcept
+        : payload{Container{container, allocator}...} {
+        ENTT_ASSERT((((stl::get<Container>(payload).size() * sizeof...(Container)) == (stl::get<Container>(payload).size() + ...)) && ...), "Unexpected container size");
+    }
+
+    /**
+     * @brief Move constructs the underlying containers using a given allocator.
+     * @tparam Allocator Type of allocator.
+     * @param container The containers to move from.
+     * @param allocator A valid allocator.
+     */
+    template<class Allocator>
+    basic_table(Container &&...container, const Allocator &allocator) noexcept
+        : payload{Container{stl::move(container), allocator}...} {
+        ENTT_ASSERT((((stl::get<Container>(payload).size() * sizeof...(Container)) == (stl::get<Container>(payload).size() + ...)) && ...), "Unexpected container size");
+    }
+
+    /**
+     * @brief Allocator-extended move constructor.
+     * @tparam Allocator Type of allocator.
+     * @param other The instance to move from.
+     * @param allocator The allocator to use.
+     */
+    template<class Allocator>
+    basic_table(basic_table &&other, const Allocator &allocator)
+        : payload{Container{stl::move(stl::get<Container>(other.payload)), allocator}...} {}
+
+    /*! @brief Default destructor. */
+    ~basic_table() = default;
+
+    /**
+     * @brief Default copy assignment operator, deleted on purpose.
+     * @return This container.
+     */
+    basic_table &operator=(const basic_table &) = delete;
+
+    /**
+     * @brief Move assignment operator.
+     * @param other The instance to move from.
+     * @return This container.
+     */
+    basic_table &operator=(basic_table &&other) noexcept {
+        swap(other);
+        return *this;
+    }
+
+    /**
+     * @brief Exchanges the contents with those of a given table.
+     * @param other Table to exchange the content with.
+     */
+    void swap(basic_table &other) noexcept {
+        using stl::swap;
+        swap(payload, other.payload);
+    }
+
+    /**
+     * @brief Increases the capacity of a table.
+     *
+     * 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) {
+        (stl::get<Container>(payload).reserve(cap), ...);
+    }
+
+    /**
+     * @brief Returns the number of rows that a table has currently allocated
+     * space for.
+     * @return Capacity of the table.
+     */
+    [[nodiscard]] size_type capacity() const noexcept {
+        return stl::get<0>(payload).capacity();
+    }
+
+    /*! @brief Requests the removal of unused capacity. */
+    void shrink_to_fit() {
+        (stl::get<Container>(payload).shrink_to_fit(), ...);
+    }
+
+    /**
+     * @brief Returns the number of rows in a table.
+     * @return Number of rows.
+     */
+    [[nodiscard]] size_type size() const noexcept {
+        return stl::get<0>(payload).size();
+    }
+
+    /**
+     * @brief Checks whether a table is empty.
+     * @return True if the table is empty, false otherwise.
+     */
+    [[nodiscard]] bool empty() const noexcept {
+        return stl::get<0>(payload).empty();
+    }
+
+    /**
+     * @brief Returns an iterator to the beginning.
+     *
+     * If the table is empty, the returned iterator will be equal to `end()`.
+     *
+     * @return An iterator to the first row of the table.
+     */
+    [[nodiscard]] const_iterator cbegin() const noexcept {
+        return {stl::get<Container>(payload).cbegin()...};
+    }
+
+    /*! @copydoc cbegin */
+    [[nodiscard]] const_iterator begin() const noexcept {
+        return cbegin();
+    }
+
+    /*! @copydoc begin */
+    [[nodiscard]] iterator begin() noexcept {
+        return {stl::get<Container>(payload).begin()...};
+    }
+
+    /**
+     * @brief Returns an iterator to the end.
+     * @return An iterator to the element following the last row of the table.
+     */
+    [[nodiscard]] const_iterator cend() const noexcept {
+        return {stl::get<Container>(payload).cend()...};
+    }
+
+    /*! @copydoc cend */
+    [[nodiscard]] const_iterator end() const noexcept {
+        return cend();
+    }
+
+    /*! @copydoc end */
+    [[nodiscard]] iterator end() noexcept {
+        return {stl::get<Container>(payload).end()...};
+    }
+
+    /**
+     * @brief Returns a reverse iterator to the beginning.
+     *
+     * If the table is empty, the returned iterator will be equal to `rend()`.
+     *
+     * @return An iterator to the first row of the reversed table.
+     */
+    [[nodiscard]] const_reverse_iterator crbegin() const noexcept {
+        return {stl::get<Container>(payload).crbegin()...};
+    }
+
+    /*! @copydoc crbegin */
+    [[nodiscard]] const_reverse_iterator rbegin() const noexcept {
+        return crbegin();
+    }
+
+    /*! @copydoc rbegin */
+    [[nodiscard]] reverse_iterator rbegin() noexcept {
+        return {stl::get<Container>(payload).rbegin()...};
+    }
+
+    /**
+     * @brief Returns a reverse iterator to the end.
+     * @return An iterator to the element following the last row of the reversed
+     * table.
+     */
+    [[nodiscard]] const_reverse_iterator crend() const noexcept {
+        return {stl::get<Container>(payload).crend()...};
+    }
+
+    /*! @copydoc crend */
+    [[nodiscard]] const_reverse_iterator rend() const noexcept {
+        return crend();
+    }
+
+    /*! @copydoc rend */
+    [[nodiscard]] reverse_iterator rend() noexcept {
+        return {stl::get<Container>(payload).rend()...};
+    }
+
+    /**
+     * @brief Appends a row to the end of a table.
+     * @tparam Args Types of arguments to use to construct the row data.
+     * @param args Parameters to use to construct the row data.
+     * @return A reference to the newly created row data.
+     */
+    template<typename... Args>
+    stl::tuple<typename Container::value_type &...> emplace(Args &&...args) {
+        if constexpr(sizeof...(Args) == 0u) {
+            return stl::forward_as_tuple(stl::get<Container>(payload).emplace_back()...);
+        } else {
+            return stl::forward_as_tuple(stl::get<Container>(payload).emplace_back(stl::forward<Args>(args))...);
+        }
+    }
+
+    /**
+     * @brief Removes a row from a table.
+     * @param pos An iterator to the row to remove.
+     * @return An iterator following the removed row.
+     */
+    iterator erase(const_iterator pos) {
+        const auto diff = pos - begin();
+        return {stl::get<Container>(payload).erase(stl::get<Container>(payload).begin() + diff)...};
+    }
+
+    /**
+     * @brief Removes a row from a table.
+     * @param pos Index of the row to remove.
+     */
+    void erase(const size_type pos) {
+        ENTT_ASSERT(pos < size(), "Index out of bounds");
+        erase(begin() + static_cast<difference_type>(pos));
+    }
+
+    /**
+     * @brief Returns the row data at specified location.
+     * @param pos The row for which to return the data.
+     * @return The row data at specified location.
+     */
+    [[nodiscard]] stl::tuple<const typename Container::value_type &...> operator[](const size_type pos) const {
+        ENTT_ASSERT(pos < size(), "Index out of bounds");
+        return stl::forward_as_tuple(stl::get<Container>(payload)[pos]...);
+    }
+
+    /*! @copydoc operator[] */
+    [[nodiscard]] stl::tuple<typename Container::value_type &...> operator[](const size_type pos) {
+        ENTT_ASSERT(pos < size(), "Index out of bounds");
+        return stl::forward_as_tuple(stl::get<Container>(payload)[pos]...);
+    }
+
+    /*! @brief Clears a table. */
+    void clear() {
+        (stl::get<Container>(payload).clear(), ...);
+    }
+
+private:
+    container_type payload;
+};
+
+} // namespace entt
+
+/*! @cond ENTT_INTERNAL */
+#include <utility>
+
+namespace std {
+
+template<typename... Container, typename Allocator>
+struct uses_allocator<entt::basic_table<Container...>, Allocator>
+    : entt::stl::bool_constant<(entt::stl::uses_allocator_v<Container, Allocator> && ...)> {};
+
+} // namespace std
+/*! @endcond */
+
+#endif