From 3bf42c6ff3805a0d42bbc661794a95ff31bedc26 Mon Sep 17 00:00:00 2001
From: untodesu <kirill@untode.su>
Date: Sat, 15 Mar 2025 16:22:09 +0500
Subject: Add whatever I was working on for the last month

---
 deps/include/entt/graph/adjacency_matrix.hpp | 336 +++++++++++++++++++++++++++
 1 file changed, 336 insertions(+)
 create mode 100644 deps/include/entt/graph/adjacency_matrix.hpp

(limited to 'deps/include/entt/graph/adjacency_matrix.hpp')

diff --git a/deps/include/entt/graph/adjacency_matrix.hpp b/deps/include/entt/graph/adjacency_matrix.hpp
new file mode 100644
index 0000000..a736aeb
--- /dev/null
+++ b/deps/include/entt/graph/adjacency_matrix.hpp
@@ -0,0 +1,336 @@
+#ifndef ENTT_GRAPH_ADJACENCY_MATRIX_HPP
+#define ENTT_GRAPH_ADJACENCY_MATRIX_HPP
+
+#include <cstddef>
+#include <iterator>
+#include <memory>
+#include <type_traits>
+#include <utility>
+#include <vector>
+#include "../config/config.h"
+#include "../core/iterator.hpp"
+#include "fwd.hpp"
+
+namespace entt {
+
+/*! @cond TURN_OFF_DOXYGEN */
+namespace internal {
+
+template<typename It>
+class edge_iterator {
+    using size_type = std::size_t;
+
+public:
+    using value_type = std::pair<size_type, size_type>;
+    using pointer = input_iterator_pointer<value_type>;
+    using reference = value_type;
+    using difference_type = std::ptrdiff_t;
+    using iterator_category = std::input_iterator_tag;
+    using iterator_concept = std::forward_iterator_tag;
+
+    constexpr edge_iterator() noexcept = default;
+
+    // NOLINTNEXTLINE(bugprone-easily-swappable-parameters)
+    constexpr edge_iterator(It base, const size_type vertices, const size_type from, const size_type to, const size_type step) noexcept
+        : it{std::move(base)},
+          vert{vertices},
+          pos{from},
+          last{to},
+          offset{step} {
+        for(; pos != last && !it[pos]; pos += offset) {}
+    }
+
+    constexpr edge_iterator &operator++() noexcept {
+        for(pos += offset; pos != last && !it[pos]; pos += offset) {}
+        return *this;
+    }
+
+    constexpr edge_iterator operator++(int) noexcept {
+        edge_iterator orig = *this;
+        return ++(*this), orig;
+    }
+
+    [[nodiscard]] constexpr reference operator*() const noexcept {
+        return *operator->();
+    }
+
+    [[nodiscard]] constexpr pointer operator->() const noexcept {
+        return std::make_pair<size_type>(pos / vert, pos % vert);
+    }
+
+    template<typename Type>
+    friend constexpr bool operator==(const edge_iterator<Type> &, const edge_iterator<Type> &) noexcept;
+
+private:
+    It it{};
+    size_type vert{};
+    size_type pos{};
+    size_type last{};
+    size_type offset{};
+};
+
+template<typename Container>
+[[nodiscard]] inline constexpr bool operator==(const edge_iterator<Container> &lhs, const edge_iterator<Container> &rhs) noexcept {
+    return lhs.pos == rhs.pos;
+}
+
+template<typename Container>
+[[nodiscard]] inline constexpr bool operator!=(const edge_iterator<Container> &lhs, const edge_iterator<Container> &rhs) noexcept {
+    return !(lhs == rhs);
+}
+
+} // namespace internal
+/*! @endcond */
+
+/**
+ * @brief Basic implementation of a directed adjacency matrix.
+ * @tparam Category Either a directed or undirected category tag.
+ * @tparam Allocator Type of allocator used to manage memory and elements.
+ */
+template<typename Category, typename Allocator>
+class adjacency_matrix {
+    using alloc_traits = std::allocator_traits<Allocator>;
+    static_assert(std::is_base_of_v<directed_tag, Category>, "Invalid graph category");
+    static_assert(std::is_same_v<typename alloc_traits::value_type, std::size_t>, "Invalid value type");
+    using container_type = std::vector<std::size_t, typename alloc_traits::template rebind_alloc<std::size_t>>;
+
+public:
+    /*! @brief Allocator type. */
+    using allocator_type = Allocator;
+    /*! @brief Unsigned integer type. */
+    using size_type = std::size_t;
+    /*! @brief Vertex type. */
+    using vertex_type = size_type;
+    /*! @brief Edge type. */
+    using edge_type = std::pair<vertex_type, vertex_type>;
+    /*! @brief Vertex iterator type. */
+    using vertex_iterator = iota_iterator<vertex_type>;
+    /*! @brief Edge iterator type. */
+    using edge_iterator = internal::edge_iterator<typename container_type::const_iterator>;
+    /*! @brief Out-edge iterator type. */
+    using out_edge_iterator = edge_iterator;
+    /*! @brief In-edge iterator type. */
+    using in_edge_iterator = edge_iterator;
+    /*! @brief Graph category tag. */
+    using graph_category = Category;
+
+    /*! @brief Default constructor. */
+    adjacency_matrix() noexcept(noexcept(allocator_type{}))
+        : adjacency_matrix{0u} {
+    }
+
+    /**
+     * @brief Constructs an empty container with a given allocator.
+     * @param allocator The allocator to use.
+     */
+    explicit adjacency_matrix(const allocator_type &allocator) noexcept
+        : adjacency_matrix{0u, allocator} {}
+
+    /**
+     * @brief Constructs an empty container with a given allocator and user
+     * supplied number of vertices.
+     * @param vertices Number of vertices.
+     * @param allocator The allocator to use.
+     */
+    adjacency_matrix(const size_type vertices, const allocator_type &allocator = allocator_type{})
+        : matrix{vertices * vertices, allocator},
+          vert{vertices} {}
+
+    /*! @brief Default copy constructor. */
+    adjacency_matrix(const adjacency_matrix &) = default;
+
+    /**
+     * @brief Allocator-extended copy constructor.
+     * @param other The instance to copy from.
+     * @param allocator The allocator to use.
+     */
+    adjacency_matrix(const adjacency_matrix &other, const allocator_type &allocator)
+        : matrix{other.matrix, allocator},
+          vert{other.vert} {}
+
+    /*! @brief Default move constructor. */
+    adjacency_matrix(adjacency_matrix &&) noexcept = default;
+
+    /**
+     * @brief Allocator-extended move constructor.
+     * @param other The instance to move from.
+     * @param allocator The allocator to use.
+     */
+    adjacency_matrix(adjacency_matrix &&other, const allocator_type &allocator)
+        : matrix{std::move(other.matrix), allocator},
+          vert{other.vert} {}
+
+    /*! @brief Default destructor. */
+    ~adjacency_matrix() noexcept = default;
+
+    /**
+     * @brief Default copy assignment operator.
+     * @return This container.
+     */
+    adjacency_matrix &operator=(const adjacency_matrix &) = default;
+
+    /**
+     * @brief Default move assignment operator.
+     * @return This container.
+     */
+    adjacency_matrix &operator=(adjacency_matrix &&) noexcept = default;
+
+    /**
+     * @brief Returns the associated allocator.
+     * @return The associated allocator.
+     */
+    [[nodiscard]] constexpr allocator_type get_allocator() const noexcept {
+        return matrix.get_allocator();
+    }
+
+    /*! @brief Clears the adjacency matrix. */
+    void clear() noexcept {
+        matrix.clear();
+        vert = {};
+    }
+
+    /**
+     * @brief Exchanges the contents with those of a given adjacency matrix.
+     * @param other Adjacency matrix to exchange the content with.
+     */
+    void swap(adjacency_matrix &other) {
+        using std::swap;
+        swap(matrix, other.matrix);
+        swap(vert, other.vert);
+    }
+
+    /**
+     * @brief Returns true if an adjacency matrix is empty, false otherwise.
+     *
+     * @warning
+     * Potentially expensive, try to avoid it on hot paths.
+     *
+     * @return True if the adjacency matrix is empty, false otherwise.
+     */
+    [[nodiscard]] bool empty() const noexcept {
+        const auto iterable = edges();
+        return (iterable.begin() == iterable.end());
+    }
+
+    /**
+     * @brief Returns the number of vertices.
+     * @return The number of vertices.
+     */
+    [[nodiscard]] size_type size() const noexcept {
+        return vert;
+    }
+
+    /**
+     * @brief Returns an iterable object to visit all vertices of a matrix.
+     * @return An iterable object to visit all vertices of a matrix.
+     */
+    [[nodiscard]] iterable_adaptor<vertex_iterator> vertices() const noexcept {
+        return {0u, vert};
+    }
+
+    /**
+     * @brief Returns an iterable object to visit all edges of a matrix.
+     * @return An iterable object to visit all edges of a matrix.
+     */
+    [[nodiscard]] iterable_adaptor<edge_iterator> edges() const noexcept {
+        const auto it = matrix.cbegin();
+        const auto sz = matrix.size();
+        return {{it, vert, 0u, sz, 1u}, {it, vert, sz, sz, 1u}};
+    }
+
+    /**
+     * @brief Returns an iterable object to visit all out-edges of a vertex.
+     * @param vertex The vertex of which to return all out-edges.
+     * @return An iterable object to visit all out-edges of a vertex.
+     */
+    [[nodiscard]] iterable_adaptor<out_edge_iterator> out_edges(const vertex_type vertex) const noexcept {
+        const auto it = matrix.cbegin();
+        const auto from = vertex * vert;
+        const auto to = from + vert;
+        return {{it, vert, from, to, 1u}, {it, vert, to, to, 1u}};
+    }
+
+    /**
+     * @brief Returns an iterable object to visit all in-edges of a vertex.
+     * @param vertex The vertex of which to return all in-edges.
+     * @return An iterable object to visit all in-edges of a vertex.
+     */
+    [[nodiscard]] iterable_adaptor<in_edge_iterator> in_edges(const vertex_type vertex) const noexcept {
+        const auto it = matrix.cbegin();
+        const auto from = vertex;
+        const auto to = vert * vert + from;
+        return {{it, vert, from, to, vert}, {it, vert, to, to, vert}};
+    }
+
+    /**
+     * @brief Resizes an adjacency matrix.
+     * @param vertices The new number of vertices.
+     */
+    void resize(const size_type vertices) {
+        adjacency_matrix other{vertices, get_allocator()};
+
+        for(auto [lhs, rhs]: edges()) {
+            other.insert(lhs, rhs);
+        }
+
+        other.swap(*this);
+    }
+
+    /**
+     * @brief Inserts an edge into the adjacency matrix, if it does not exist.
+     * @param lhs The left hand vertex of the edge.
+     * @param rhs The right hand vertex of the edge.
+     * @return A pair consisting of an iterator to the inserted element (or to
+     * the element that prevented the insertion) and a bool denoting whether the
+     * insertion took place.
+     */
+    std::pair<edge_iterator, bool> insert(const vertex_type lhs, const vertex_type rhs) {
+        const auto pos = lhs * vert + rhs;
+
+        if constexpr(std::is_same_v<graph_category, undirected_tag>) {
+            const auto rev = rhs * vert + lhs;
+            ENTT_ASSERT(matrix[pos] == matrix[rev], "Something went really wrong");
+            matrix[rev] = 1u;
+        }
+
+        const auto inserted = !std::exchange(matrix[pos], 1u);
+        return {edge_iterator{matrix.cbegin(), vert, pos, matrix.size(), 1u}, inserted};
+    }
+
+    /**
+     * @brief Removes the edge associated with a pair of given vertices.
+     * @param lhs The left hand vertex of the edge.
+     * @param rhs The right hand vertex of the edge.
+     * @return Number of elements removed (either 0 or 1).
+     */
+    size_type erase(const vertex_type lhs, const vertex_type rhs) {
+        const auto pos = lhs * vert + rhs;
+
+        if constexpr(std::is_same_v<graph_category, undirected_tag>) {
+            const auto rev = rhs * vert + lhs;
+            ENTT_ASSERT(matrix[pos] == matrix[rev], "Something went really wrong");
+            matrix[rev] = 0u;
+        }
+
+        return std::exchange(matrix[pos], 0u);
+    }
+
+    /**
+     * @brief Checks if an adjacency matrix contains a given edge.
+     * @param lhs The left hand vertex of the edge.
+     * @param rhs The right hand vertex of the edge.
+     * @return True if there is such an edge, false otherwise.
+     */
+    [[nodiscard]] bool contains(const vertex_type lhs, const vertex_type rhs) const {
+        const auto pos = lhs * vert + rhs;
+        return pos < matrix.size() && matrix[pos];
+    }
+
+private:
+    container_type matrix;
+    size_type vert;
+};
+
+} // namespace entt
+
+#endif
-- 
cgit