From 05fef93d8afbd53c5d17f839e209cc4b659491c2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Carsten=20Gr=C3=A4ser?= <graeser@dune-project.org>
Date: Wed, 24 Aug 2016 00:09:57 +0200
Subject: [PATCH] Add template alias ConstCopyOrReference
This adds constness to the stored copy or reference.
Notice that simply using CopyOrReference<const T> for
ConstCopyOrReference<T> does not work since 'const T'
is the same as T for reference types because all references
are const.
---
dune/solvers/common/copyorreference.hh | 23 ++++++++++++++++++++++-
1 file changed, 22 insertions(+), 1 deletion(-)
diff --git a/dune/solvers/common/copyorreference.hh b/dune/solvers/common/copyorreference.hh
index c130c567..b03ea815 100644
--- a/dune/solvers/common/copyorreference.hh
+++ b/dune/solvers/common/copyorreference.hh
@@ -17,7 +17,7 @@ namespace Solvers {
/**
* \brief A wrapper storing either a copy or reference
*
- * \tparam T Type to be refered to
+ * \tparam T Type to be stored
*
* If T is of reference type, the wrapper stores a reference
* to the passed object. Otherwise it stores a copy.
@@ -114,6 +114,27 @@ private:
+/**
+ * \brief A wrapper storing either a const copy or const reference
+ *
+ * \tparam T Type to be stored
+ *
+ * This is an alias for CopyOrReference<TT> where TT
+ * is either 'const T' if T is a raw type or 'const S&'
+ * if T is a 'S&'. Notice that in the latter case this
+ * is different from 'const T' which would be the same
+ * as T.
+ */
+template<class T>
+using ConstCopyOrReference =
+ CopyOrReference<
+ std::conditional_t<
+ std::is_reference<T>::value,
+ const std::remove_reference_t<T>&,
+ const T>>;
+
+
+
} // end namespace Solvers
} // end namespace Dune
--
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