From c913f38dfc90a9b39038013fd4928fe5914dc7fd Mon Sep 17 00:00:00 2001
From: Christoph Lehmann <christoph.lehmann@ufz.de>
Date: Wed, 6 Jul 2016 12:36:08 +0200
Subject: [PATCH] [BL] added metaprogramming integer sequence
---
BaseLib/TMPUtil.h | 46 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 46 insertions(+)
create mode 100644 BaseLib/TMPUtil.h
diff --git a/BaseLib/TMPUtil.h b/BaseLib/TMPUtil.h
new file mode 100644
index 00000000000..7fc6c70173d
--- /dev/null
+++ b/BaseLib/TMPUtil.h
@@ -0,0 +1,46 @@
+/**
+ * \copyright
+ * Copyright (c) 2012-2016, OpenGeoSys Community (http://www.opengeosys.org)
+ * Distributed under a Modified BSD License.
+ * See accompanying file LICENSE.txt or
+ * http://www.opengeosys.org/project/license
+ *
+ */
+
+#ifndef BASELIB_TMPUTIL_H
+#define BASELIB_TMPUTIL_H
+
+namespace BaseLib
+{
+//! Has sequence of integers as template parameters
+template <int...>
+struct IntegerSequence {
+};
+
+//! Generates an IntegerSequence.
+//!
+//! \see http://stackoverflow.com/a/7858971
+template <int N, int... S>
+struct GenerateIntegerSequence {
+ // effectively pushes N-1 from the left to the list int... S of integers.
+ typedef typename GenerateIntegerSequence<N - 1, N - 1, S...>::type type;
+};
+
+template <int... S>
+struct GenerateIntegerSequence<0, S...> {
+ typedef IntegerSequence<S...> type;
+};
+/* The template metaprogram proceeds in the following way:
+ *
+ * GenerateIntegerSequence<sizeof...(Args)>::type
+ *
+ * Assume sizeof...(Args) == 3. Let GIS := GenerateIntegerSequence
+ * GIS<3, []>
+ * -> GIS<2, [2]>
+ * -> GIS<1, [1, 2]>
+ * -> GIS<0, [0, 1, 2], which has member typedef IntegerSequence<0, 1, 2>
+ */
+
+} // namespace BaseLib
+
+#endif // BASELIB_TMPUTIL_H
--
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