Initialize at openlb-1-3

1 files changed, 95 insertions, 0 deletions

diff --git a/src/utilities/meta.h b/src/utilities/meta.h
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+++ b/src/utilities/meta.h
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+/*  This file is part of the OpenLB library
+ *
+ *  Copyright (C) 2019 Adrian Kummerlaender
+ *  E-mail contact: info@openlb.net
+ *  The most recent release of OpenLB can be downloaded at
+ *  <http://www.openlb.net/>
+ *
+ *  This program is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License
+ *  as published by the Free Software Foundation; either version 2
+ *  of the License, or (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public
+ *  License along with this program; if not, write to the Free
+ *  Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ *  Boston, MA  02110-1301, USA.
+*/
+
+#ifndef UTILITIES_META_H
+#define UTILITIES_META_H
+
+#include <type_traits>
+
+namespace olb {
+
+namespace utilities {
+
+namespace meta {
+
+/// Provide implementation of std::enable_if_t
+/**
+ * Weirdly version 18.0.3 of the Intel C++ compiler doesn't provide this
+ * useful template alias despite otherwise supporting C++14.
+ **/
+template<bool B, class T = void>
+using enable_if_t = typename std::enable_if<B,T>::type;
+
+/// Check whether a given type list contains WANTED
+template <
+  typename WANTED,
+  typename HEAD = void, // Default argument in case the list is empty
+  typename... TAIL
+>
+struct list_contains_item {
+  using type = typename std::conditional<
+    std::is_same<WANTED, HEAD>::value,
+    std::true_type,
+    typename list_contains_item<WANTED, TAIL...>::type
+  >::type;
+};
+
+template <typename WANTED, typename HEAD>
+struct list_contains_item<WANTED, HEAD> {
+  using type = typename std::is_same<WANTED, HEAD>::type;
+};
+
+
+/// Get first type based on BASE contained in a given type list
+/**
+ * If no such list item exists, type is void.
+ **/
+template <
+  typename BASE,
+  typename HEAD = void, // Default argument in case the list is empty
+  typename... TAIL
+>
+struct list_item_with_base {
+  using type = typename std::conditional<
+    std::is_base_of<BASE, HEAD>::value,
+    HEAD,
+    typename list_item_with_base<BASE, TAIL...>::type
+  >::type;
+};
+
+template <typename BASE, typename HEAD>
+struct list_item_with_base<BASE, HEAD> {
+  using type = typename std::conditional<
+    std::is_base_of<BASE, HEAD>::value,
+    HEAD,
+    void
+  >::type;
+};
+
+}
+
+}
+
+}
+
+#endif