From f219e868064c5bb8887cbf2728c5840babdaee25 Mon Sep 17 00:00:00 2001
From: John Wellbelove <john.wellbelove@etlcpp.com>
Date: Fri, 2 Aug 2024 09:51:30 +0100
Subject: [PATCH] Added etl::count_of, etl::has_duplicates,
 etl::has_duplicates_of

---
 .../etl/generators/type_traits_generator.h    | 60 +++++++++++++++++--
 include/etl/type_traits.h                     | 60 +++++++++++++++++--
 test/test_type_traits.cpp                     | 46 ++++++++++++++
 3 files changed, 158 insertions(+), 8 deletions(-)

diff --git a/include/etl/generators/type_traits_generator.h b/include/etl/generators/type_traits_generator.h
index c1d73d103..f086b8414 100644
--- a/include/etl/generators/type_traits_generator.h
+++ b/include/etl/generators/type_traits_generator.h
@@ -2296,16 +2296,68 @@ typedef integral_constant<bool, true>  true_type;
   using signed_type_t = typename signed_type<T>::type;
 #endif
 
-//*********************************************
-// type_identity
+  //*********************************************
+  // type_identity
 
-template <typename T>
-struct type_identity { typedef T type; };
+  template <typename T>
+  struct type_identity { typedef T type; };
 
 #if ETL_USING_CPP11
   template <typename T>
   using type_identity_t = typename type_identity<T>::type;
 #endif
+
+#if ETL_USING_CPP11
+  //*********************************************
+  // has_duplicates
+  template <typename... TTypes>
+  struct has_duplicates;
+
+  template <typename TFirst, typename... TRest>
+  struct has_duplicates<TFirst, TRest...> : etl::conditional_t<etl::is_one_of<TFirst, TRest...>::value,
+                                                               etl::true_type,
+                                                               has_duplicates<TRest...>> {};
+
+  template <>
+  struct has_duplicates<> : etl::false_type {};
+#endif
+
+#if ETL_USING_CPP17
+  template <typename... TTypes>
+  inline constexpr bool has_duplicates_v = etl::has_duplicates<TTypes...>::value;
+#endif
+
+#if ETL_USING_CPP11
+  //*********************************************
+  // count_of
+  template <typename T, typename... TTypes>
+  struct count_of;
+
+  template <typename T, typename U, typename... URest>
+  struct count_of<T, U, URest...> : etl::integral_constant<size_t,
+                                                            etl::is_same<T, U>::value +
+                                                              count_of<T, URest...>::value> {};
+
+  template <typename T>
+  struct count_of<T> : etl::integral_constant<size_t, 0> {};
+#endif
+
+#if ETL_USING_CPP17
+  template <typename T, typename... TTypes>
+  inline constexpr size_t count_of_v = etl::count_of<T, TTypes...>::value;
+#endif
+
+#if ETL_USING_CPP11
+  //*********************************************
+  // has_duplicates_of
+  template <typename T, typename... TTypes>
+  struct has_duplicates_of : etl::bool_constant<(etl::count_of<T, TTypes...>::value > 1U)> {};
+#endif
+
+#if ETL_USING_CPP17
+  template <typename T, typename... TTypes>
+  inline constexpr bool has_duplicates_of_v = etl::has_duplicates_of<T, TTypes...>::value;
+#endif
 }
 
 // Helper macros
diff --git a/include/etl/type_traits.h b/include/etl/type_traits.h
index 1a40f0264..795789945 100644
--- a/include/etl/type_traits.h
+++ b/include/etl/type_traits.h
@@ -2289,16 +2289,68 @@ typedef integral_constant<bool, true>  true_type;
   using signed_type_t = typename signed_type<T>::type;
 #endif
 
-//*********************************************
-// type_identity
+  //*********************************************
+  // type_identity
 
-template <typename T>
-struct type_identity { typedef T type; };
+  template <typename T>
+  struct type_identity { typedef T type; };
 
 #if ETL_USING_CPP11
   template <typename T>
   using type_identity_t = typename type_identity<T>::type;
 #endif
+
+#if ETL_USING_CPP11
+  //*********************************************
+  // has_duplicates
+  template <typename... TTypes>
+  struct has_duplicates;
+
+  template <typename TFirst, typename... TRest>
+  struct has_duplicates<TFirst, TRest...> : etl::conditional_t<etl::is_one_of<TFirst, TRest...>::value,
+                                                               etl::true_type,
+                                                               has_duplicates<TRest...>> {};
+
+  template <>
+  struct has_duplicates<> : etl::false_type {};
+#endif
+
+#if ETL_USING_CPP17
+  template <typename... TTypes>
+  inline constexpr bool has_duplicates_v = etl::has_duplicates<TTypes...>::value;
+#endif
+
+#if ETL_USING_CPP11
+  //*********************************************
+  // count_of
+  template <typename T, typename... TTypes>
+  struct count_of;
+
+  template <typename T, typename U, typename... URest>
+  struct count_of<T, U, URest...> : etl::integral_constant<size_t,
+                                                            etl::is_same<T, U>::value +
+                                                              count_of<T, URest...>::value> {};
+
+  template <typename T>
+  struct count_of<T> : etl::integral_constant<size_t, 0> {};
+#endif
+
+#if ETL_USING_CPP17
+  template <typename T, typename... TTypes>
+  inline constexpr size_t count_of_v = etl::count_of<T, TTypes...>::value;
+#endif
+
+#if ETL_USING_CPP11
+  //*********************************************
+  // has_duplicates_of
+  template <typename T, typename... TTypes>
+  struct has_duplicates_of : etl::bool_constant<(etl::count_of<T, TTypes...>::value > 1U)> {};
+#endif
+
+#if ETL_USING_CPP17
+  template <typename T, typename... TTypes>
+  inline constexpr bool has_duplicates_of_v = etl::has_duplicates_of<T, TTypes...>::value;
+#endif
 }
 
 // Helper macros
diff --git a/test/test_type_traits.cpp b/test/test_type_traits.cpp
index 7b1979cac..4316a697f 100644
--- a/test/test_type_traits.cpp
+++ b/test/test_type_traits.cpp
@@ -1333,4 +1333,50 @@ namespace
   {
     CHECK_CLOSE(type_identity_test_add(1.5f, 2), 3.5f, 0.01f);
   }
+
+  //*************************************************************************
+  TEST(test_has_duplicates)
+  {
+#if ETL_USING_CPP17
+    CHECK_FALSE((etl::has_duplicates_v<char>));
+    CHECK_FALSE((etl::has_duplicates_v<char, int, double>));
+    CHECK_TRUE((etl::has_duplicates_v<char, int, char>));
+#else
+    CHECK_FALSE((etl::has_duplicates<char>::value));
+    CHECK_FALSE((etl::has_duplicates<char, int, double>::value));
+    CHECK_TRUE((etl::has_duplicates<char, int, char>::value));
+#endif
+  }
+
+  //*************************************************************************
+  TEST(test_has_duplicates_of)
+  {
+#if ETL_USING_CPP17
+    CHECK_FALSE((etl::has_duplicates_of_v<char>));
+    CHECK_TRUE((etl::has_duplicates_of_v<char, char, int, char>)); // char is duplicated.
+    CHECK_FALSE((etl::has_duplicates_of_v<int, char, int, char>)); // int is not duplicated.
+#else
+    CHECK_FALSE((etl::has_duplicates_of<char>::value));
+    CHECK_TRUE((etl::has_duplicates_of<char, char, int, char>::value)); // char is duplicated.
+    CHECK_FALSE((etl::has_duplicates_of<int, char, int, char>::value)); // int is not duplicated.
+#endif
+  }
+
+  //*************************************************************************
+  TEST(test_count_of)
+  {
+#if ETL_USING_CPP17
+    CHECK_EQUAL(0, (etl::count_of_v<char>));
+    CHECK_EQUAL(0, (etl::count_of_v<char, int>));
+    CHECK_EQUAL(1, (etl::count_of_v<char, char>));
+    CHECK_EQUAL(1, (etl::count_of_v<char, int, char>));
+    CHECK_EQUAL(2, (etl::count_of_v<char, int, char, double, char>));
+#else
+    CHECK_EQUAL(0, (etl::count_of<char>::value));
+    CHECK_EQUAL(0, (etl::count_of<char, int>::value));
+    CHECK_EQUAL(1, (etl::count_of<char, char>::value));
+    CHECK_EQUAL(1, (etl::count_of<char, int, char>::value));
+    CHECK_EQUAL(2, (etl::count_of<char, int, char, double, char>::value));
+#endif
+  }
 }