feat: Implement hash module for enhanced type hashing and value retrieval

Signed-off-by: FrozenlemonTee <1115306170@qq.com>

Author: FrozenLemonTee

src/algorithms/hash.cppm

@@ -0,0 +1,79 @@
+module;
+
+#include <concepts>
+#include <cstddef>
+#include <functional>
+#include <type_traits>
+
+export module mcpplibs.primitives.algorithms.hash;
+
+import mcpplibs.primitives.underlying;
+
+namespace mcpplibs::primitives::algorithms::details {
+
+template <typename T>
+concept std_hashable = requires(std::remove_cv_t<T> const &value) {
+  {
+    std::hash<std::remove_cv_t<T>>{}(value)
+  } -> std::convertible_to<std::size_t>;
+};
+
+} // namespace mcpplibs::primitives::algorithms::details
+
+export namespace mcpplibs::primitives::algorithms {
+
+template <typename T> struct hash {
+  using value_type = std::remove_cv_t<T>;
+  using result_type = std::size_t;
+
+  static constexpr bool enabled = false;
+
+  auto operator()(value_type const &) const noexcept -> result_type {
+    return result_type{};
+  }
+};
+
+template <typename T>
+using hash_result_t = hash<std::remove_cvref_t<T>>::result_type;
+
+template <typename T>
+concept hashable = hash<std::remove_cvref_t<T>>::enabled;
+
+template <typename T>
+  requires details::std_hashable<T>
+struct hash<T> {
+  using value_type = std::remove_cv_t<T>;
+  using result_type = std::size_t;
+
+  static constexpr bool enabled = true;
+
+  auto operator()(value_type const &value) const noexcept(
+      noexcept(std::hash<value_type>{}(value))) -> result_type {
+    return std::hash<value_type>{}(value);
+  }
+};
+
+template <underlying_type T>
+  requires (!details::std_hashable<T> &&
+            hash<typename underlying::traits<std::remove_cv_t<T>>::rep_type>::enabled)
+struct hash<T> {
+  using value_type = std::remove_cv_t<T>;
+  using rep_type = underlying::traits<value_type>::rep_type;
+  using result_type = hash_result_t<rep_type>;
+
+  static constexpr bool enabled = true;
+
+  auto operator()(value_type const &value) const noexcept(
+      noexcept(hash<rep_type>{}(underlying::traits<value_type>::to_rep(value))))
+      -> result_type {
+    return hash<rep_type>{}(underlying::traits<value_type>::to_rep(value));
+  }
+};
+
+template <hashable T>
+auto hash_value(T const &value) noexcept(
+    noexcept(hash<std::remove_cvref_t<T>>{}(value))) -> hash_result_t<T> {
+  return hash<std::remove_cvref_t<T>>{}(value);
+}
+
+} // namespace mcpplibs::primitives::algorithms