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ide-touchgfx-gen/Middlewares/ST/touchgfx/framework/include/common/Meta.hpp

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+/**
+  ******************************************************************************
+  * This file is part of the TouchGFX 4.16.1 distribution.
+  *
+  * <h2><center>&copy; Copyright (c) 2021 STMicroelectronics.
+  * All rights reserved.</center></h2>
+  *
+  * This software component is licensed by ST under Ultimate Liberty license
+  * SLA0044, the "License"; You may not use this file except in compliance with
+  * the License. You may obtain a copy of the License at:
+  *                             www.st.com/SLA0044
+  *
+  ******************************************************************************
+  */
+
+/**
+ * @file common/Meta.hpp
+ *
+ * Declares the touchgfx::meta namespace.
+ */
+#ifndef META_HPP
+#define META_HPP
+
+namespace touchgfx
+{
+/**
+ * Template meta-programming tools are grouped in this namespace
+ */
+namespace meta
+{
+/** Nil-type, indicates the end of a TypeList. */
+struct Nil
+{
+};
+
+/**
+ * TypeList, used for generating compile-time lists of types.
+ *
+ * @tparam First Type of the first.
+ * @tparam Next  Type of the next.
+ */
+template <typename First, typename Next>
+struct TypeList
+{
+    typedef First first; ///< The first element in the TypeList
+    typedef Next next;   ///< Remainder of the TypeList
+};
+
+/**
+ * Meta-function, selects the "maximum" type, i.e. the largest type.
+ *
+ * @tparam T1      Generic type parameter.
+ * @tparam T2      Generic type parameter.
+ * @tparam choose1 True if sizeof(T1) is larger than sizeof(T2).
+ * @param  parameter1 The first parameter.
+ */
+template < typename T1, typename T2, bool choose1 = (sizeof(T1) > sizeof(T2)) >
+struct type_max
+{
+    typedef T1 type; ///< The resulting type (default case: sizeof(T1)>sizeof(T2))
+};
+
+/**
+ * Specialization for the case where sizeof(T2) >= sizeof(T1).
+ *
+ * @tparam T1 Generic type parameter.
+ * @tparam T2 Generic type parameter.
+ */
+template <typename T1, typename T2>
+struct type_max<T1, T2, false>
+{
+    typedef T2 type; ///< The resulting type (default case: sizeof(T2)>=sizeof(T1))
+};
+
+/**
+ * Meta-function signature, selects maximum type from TypeList.
+ *
+ * @tparam T Generic type parameter.
+ */
+template <typename T>
+struct select_type_maxsize;
+
+/**
+ * Specialization to dive into the list (inherits result from type_max).
+ *
+ * @tparam First Type of the first.
+ * @tparam Next  Type of the next.
+ */
+template <typename First, typename Next>
+struct select_type_maxsize<TypeList<First, Next> > : public type_max<First, typename select_type_maxsize<Next>::type>
+{
+};
+
+/**
+ * Specialization for loop termination (when type Nil encountered).
+ *
+ * @tparam First Type of the first.
+ */
+template <typename First>
+struct select_type_maxsize<TypeList<First, Nil> >
+{
+    typedef First type;
+};
+
+/**
+ * Meta-function signature, joins typelist with type (or another typelist).
+ *
+ * @tparam TList Type of the list.
+ * @tparam T     Generic type parameter.
+ */
+template <typename TList, typename T>
+struct list_join;
+
+/** Specialization for termination. */
+template <>
+struct list_join<Nil, Nil>
+{
+    typedef Nil result;
+};
+
+/**
+ * Specialization for "end-of-LHS", with RHS as type.
+ *
+ * @tparam T Generic type parameter.
+ */
+template <typename T>
+struct list_join<Nil, T>
+{
+    typedef TypeList<T, Nil> result;
+};
+
+/**
+ * Specialization for "end-of-LHS", with RHS as a TypeList.
+ *
+ * @tparam First Type of the first.
+ * @tparam Next  Type of the next.
+ */
+template <typename First, typename Next>
+struct list_join<Nil, TypeList<First, Next> >
+{
+    typedef TypeList<First, Next> result;
+};
+
+/**
+ * Recursively joins a typelist (LHS) with a type or a type-list (RHS).
+ *
+ * @tparam First Type of the first.
+ * @tparam Next  Type of the next.
+ * @tparam T     Generic type parameter.
+ */
+template <typename First, typename Next, typename T>
+struct list_join<TypeList<First, Next>, T>
+{
+    typedef TypeList<First, typename list_join<Next, T>::result> result;
+};
+
+} // namespace meta
+
+} // namespace touchgfx
+
+#endif // META_HPP