feat(memory): add UnorderedBimap

core/include/cubos/core/memory/unordered_bimap.hpp

@@ -0,0 +1,164 @@
+/// @file
+/// @brief Class @ref cubos::core::memory::UnorderedBimap.
+/// @ingroup core-memory
+
+#pragma once
+
+#include <unordered_map>
+
+namespace cubos::core::memory
+{
+    /// @brief A bidirectional hash table.
+    /// @tparam L Left type.
+    /// @tparam R Right type.
+    /// @tparam LHash Hash functor type for @p L.
+    /// @tparam RHash Hash functor type for @p R.
+    /// @ingroup core-memory
+    template <typename L, typename R, typename LHash = std::hash<L>, typename RHash = std::hash<R>>
+    class UnorderedBimap final
+    {
+    public:
+        using Iterator = std::unordered_map<L, R, LHash>::const_iterator;
+
+        /// @brief Adds a new entry to the map.
+        /// @note If any of the values already exists, the old entries with them are removed.
+        /// @param left Left value.
+        /// @param right Right value.
+        void add(L left, R right)
+        {
+            auto leftIt = mLeftToRight.find(left);
+            if (leftIt != mLeftToRight.end())
+            {
+                mRightToLeft.erase(leftIt->second);
+            }
+
+            auto rightIt = mRightToLeft.find(right);
+            if (rightIt != mRightToLeft.end())
+            {
+                mLeftToRight.erase(rightIt->second);
+            }
+
+            mLeftToRight.insert_or_assign(left, right);
+            mRightToLeft.insert_or_assign(right, left);
+        }
+
+        /// @brief Removes the entry associated to the given left value.
+        /// @param left Left value.
+        /// @return Whether the entry was removed.
+        bool removeLeft(const L& left)
+        {
+            auto it = mLeftToRight.find(left);
+            if (it == mLeftToRight.end())
+            {
+                return false;
+            }
+
+            mRightToLeft.erase(it->second);
+            mLeftToRight.erase(it);
+            return true;
+        }
+
+        /// @brief Removes the entry associated to the given right value.
+        /// @param right Right value.
+        /// @return Whether the entry was removed.
+        bool removeRight(const R& right)
+        {
+            auto it = mRightToLeft.find(right);
+            if (it == mRightToLeft.end())
+            {
+                return false;
+            }
+
+            mLeftToRight.erase(it->second);
+            mRightToLeft.erase(it);
+            return true;
+        }
+
+        /// @brief Checks if the map has the given entry.
+        /// @param left Left value.
+        /// @param right Right value.
+        /// @return Whether the map has the entry.
+        bool has(const L& left, const R& right) const
+        {
+            auto it = mLeftToRight.find(left);
+            if (it == mLeftToRight.end())
+            {
+                return false;
+            }
+            return it->second == right;
+        }
+
+        /// @brief Checks if the map contains the given left value.
+        /// @param left Left value.
+        /// @return Whether the map contains the value.
+        bool hasLeft(const L& left) const
+        {
+            return mLeftToRight.find(left) != mLeftToRight.end();
+        }
+
+        /// @brief Checks if the map contains the given right value.
+        /// @param right Right value.
+        /// @return Whether the map contains the value.
+        bool hasRight(const R& right) const
+        {
+            return mRightToLeft.find(right) != mRightToLeft.end();
+        }
+
+        /// @brief Gets the right value associated to the given left value.
+        /// @note Aborts if the left value isn't stored.
+        /// @param left Left value.
+        /// @return Right value.
+        const R& getRight(const L& left) const
+        {
+            return mLeftToRight.at(left);
+        }
+
+        /// @brief Gets the left value associated to the given right value.
+        /// @note Aborts if the right value isn't stored.
+        /// @param right Right value.
+        /// @return Left value.
+        const L& getLeft(const R& right) const
+        {
+            return mRightToLeft.at(right);
+        }
+
+        /// @brief Clears the map.
+        void clear()
+        {
+            mLeftToRight.clear();
+            mRightToLeft.clear();
+        }
+
+        /// @brief Gets the number of entries in the map.
+        /// @return Entry count.
+        std::size_t size() const
+        {
+            return mLeftToRight.size();
+        }
+
+        /// @brief Checks if the map is empty.
+        /// @return Whether the map is empty.
+        bool empty() const
+        {
+            return mLeftToRight.empty();
+        }
+
+        /// @brief Gets an iterator to the beginning of the map.
+        /// @return Iterator.
+        Iterator begin() const
+        {
+            return mLeftToRight.begin();
+        }
+
+        /// @brief Gets an iterator to the end of the map.
+        /// @return Iterator.
+        Iterator end() const
+        {
+            return mLeftToRight.end();
+        }
+
+    private:
+        std::unordered_map<L, R, LHash> mLeftToRight;
+        std::unordered_map<R, L, RHash> mRightToLeft;
+    };
+} // namespace cubos::core::memory

core/tests/CMakeLists.txt

@@ -22,6 +22,8 @@ add_executable(
     data/fs/file_system.cpp
     data/context.cpp
 
+    memory/unordered_bimap.cpp
+
     ecs/registry.cpp
     ecs/world.cpp
     ecs/query.cpp

core/tests/memory/unordered_bimap.cpp

@@ -0,0 +1,74 @@
+#include <doctest/doctest.h>
+
+#include <cubos/core/memory/unordered_bimap.hpp>
+
+TEST_CASE("memory::UnorderedBimap")
+{
+    using cubos::core::memory::UnorderedBimap;
+
+    UnorderedBimap<int, char> bimap{};
+
+    SUBCASE("just initialized")
+    {
+    }
+
+    SUBCASE("had entries")
+    {
+        bimap.add(1, 'a');
+
+        CHECK_FALSE(bimap.empty());
+        CHECK(bimap.size() == 1);
+
+        CHECK(bimap.has(1, 'a'));
+        CHECK(bimap.hasLeft(1));
+        CHECK(bimap.hasRight('a'));
+        CHECK(bimap.getLeft('a') == 1);
+        CHECK(bimap.getRight(1) == 'a');
+
+        CHECK(bimap.begin() != bimap.end());
+        CHECK(bimap.begin()->first == 1);
+        CHECK(bimap.begin()->second == 'a');
+        CHECK(++bimap.begin() == bimap.end());
+
+        bimap.add(2, 'b');
+
+        CHECK(bimap.size() == 2);
+        CHECK(bimap.has(1, 'a'));
+        CHECK(bimap.has(2, 'b'));
+
+        bimap.add(1, 'b');
+
+        CHECK(bimap.size() == 1);
+        CHECK(bimap.has(1, 'b'));
+        CHECK_FALSE(bimap.has(1, 'a'));
+        CHECK_FALSE(bimap.has(2, 'b'));
+
+        SUBCASE("remove left")
+        {
+            CHECK(bimap.removeLeft(1));
+        }
+
+        SUBCASE("remove right")
+        {
+            CHECK(bimap.removeRight('b'));
+        }
+
+        SUBCASE("clear")
+        {
+            bimap.clear();
+        }
+    }
+
+    // Shouldn't contain anything
+    CHECK(bimap.empty());
+    CHECK(bimap.size() == 0);
+
+    CHECK_FALSE(bimap.has(1, 'a'));
+    CHECK_FALSE(bimap.hasLeft(1));
+    CHECK_FALSE(bimap.hasRight('a'));
+
+    CHECK(bimap.begin() == bimap.end());
+
+    CHECK_FALSE(bimap.removeLeft(1));
+    CHECK_FALSE(bimap.removeRight('a'));
+}