1 files changed, 53 insertions, 0 deletions
diff --git a/libs/kstd/kstd/flat_map.hpp b/libs/kstd/kstd/flat_map.hpp
index f00956a5..dcf73392 100644
--- a/libs/kstd/kstd/flat_map.hpp
+++ b/libs/kstd/kstd/flat_map.hpp
@@ -872,6 +872,59 @@ namespace kstd
       return iterator{m_containers, offset};
     }
 
+    //! Get a range of elements whose keys compare equal to the given key.
+    //!
+    //! @param key The key to look for.
+    //! @return A pair of iterators describing the, possibly empty, range of elements.
+    [[nodiscard]] constexpr auto equal_range(key_type const & key) noexcept -> std::pair<iterator, iterator>
+    {
+      auto found = std::ranges::equal_range(m_containers.keys, key, m_comparator);
+      auto start_offset = static_cast<std::size_t>(std::ranges::distance(m_containers.keys.begin(), found.begin()));
+      auto end_offset = static_cast<std::size_t>(std::ranges::distance(m_containers.keys.begin(), found.end()));
+      return std::make_pair(iterator{m_containers, start_offset}, iterator{m_containers, end_offset});
+    }
+
+    //! Get a range of elements whose keys compare equal to the given key.
+    //!
+    //! @param key The key to look for.
+    //! @return A pair of iterators describing the, possibly empty, range of elements.
+    [[nodiscard]] constexpr auto equal_range(key_type const & key) const noexcept
+        -> std::pair<const_iterator, const_iterator>
+    {
+      auto found = std::ranges::equal_range(m_containers.keys, key, m_comparator);
+      auto start_offset = static_cast<std::size_t>(std::ranges::distance(m_containers.keys.begin(), found.begin()));
+      auto end_offset = static_cast<std::size_t>(std::ranges::distance(m_containers.keys.begin(), found.end()));
+      return std::make_pair(iterator{m_containers, start_offset}, iterator{m_containers, end_offset});
+    }
+
+    //! Get a range of elements whose keys compare equal to the given key.
+    //!
+    //! @param key The key to look for.
+    //! @return A pair of iterators describing the, possibly empty, range of elements.
+    template<typename K>
+      requires requires { typename key_compare::is_transparent; }
+    [[nodiscard]] constexpr auto equal_range(K const & key) noexcept -> std::pair<iterator, iterator>
+    {
+      auto found = std::ranges::equal_range(m_containers.keys, key, m_comparator);
+      auto start_offset = static_cast<std::size_t>(std::ranges::distance(m_containers.keys.begin(), found.begin()));
+      auto end_offset = static_cast<std::size_t>(std::ranges::distance(m_containers.keys.begin(), found.end()));
+      return std::make_pair(iterator{m_containers, start_offset}, iterator{m_containers, end_offset});
+    }
+
+    //! Get a range of elements whose keys compare equal to the given key.
+    //!
+    //! @param key The key to look for.
+    //! @return A pair of iterators describing the, possibly empty, range of elements.
+    template<typename K>
+      requires requires { typename key_compare::is_transparent; }
+    [[nodiscard]] constexpr auto equal_range(K const & key) const noexcept -> std::pair<const_iterator, const_iterator>
+    {
+      auto found = std::ranges::equal_range(m_containers.keys, key, m_comparator);
+      auto start_offset = static_cast<std::size_t>(std::ranges::distance(m_containers.keys.begin(), found.begin()));
+      auto end_offset = static_cast<std::size_t>(std::ranges::distance(m_containers.keys.begin(), found.end()));
+      return std::make_pair(iterator{m_containers, start_offset}, iterator{m_containers, end_offset});
+    }
+
     //! Get the key comparator of this flat map.
     //!
     //! @return The key comparator of this flat map.