memory: added utility function fast_mod

src/entt/core/memory.hpp

@@ -89,6 +89,19 @@ template<std::size_t Value>
 inline constexpr bool is_power_of_two_v = is_power_of_two<Value>::value;
 
 
+/**
+ * @brief Fast module utility function (powers of two only).
+ * @tparam Value Compile-time page size, it must be a power of two.
+ * @param value A value for which to calculate the modulus.
+ * @return Remainder of division.
+ */
+template<std::size_t Value>
+[[nodiscard]] constexpr std::size_t fast_mod(const std::size_t value) ENTT_NOEXCEPT {
+    static_assert(is_power_of_two_v<Value>, "Value must be a power of two");
+    return value & (Value - 1u);
+}
+
+
 }
 
 

test/entt/core/memory.cpp

@@ -41,3 +41,9 @@ TEST(Memory, IsPowerOfTwo) {
     ASSERT_TRUE(entt::is_power_of_two_v<128u>);
     ASSERT_FALSE(entt::is_power_of_two_v<200u>);
 }
+
+TEST(Memory, FastMod) {
+    ASSERT_EQ(entt::fast_mod<8u>(0u), 0u);
+    ASSERT_EQ(entt::fast_mod<8u>(7u), 7u);
+    ASSERT_EQ(entt::fast_mod<8u>(8u), 0u);
+}