From d8558a3af333ee02603a4a07c5bc7031d624f72b Mon Sep 17 00:00:00 2001
From: Max Kellermann <max@duempel.org>
Date: Mon, 14 Jul 2014 16:44:17 +0200
Subject: [PATCH] util/Cast: add "const" overload

---
 src/util/Cast.hxx | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/src/util/Cast.hxx b/src/util/Cast.hxx
index c49d18eaa..887137da4 100644
--- a/src/util/Cast.hxx
+++ b/src/util/Cast.hxx
@@ -93,4 +93,17 @@ ContainerCast(A &a, A C::*member)
 	return *OffsetCast<C, A>(&a, ContainerAttributeOffset<C, A>(member));
 }
 
+/**
+ * Cast the given pointer to a struct member to its parent structure.
+ */
+template<class C, class A>
+#if defined(__clang__) || GCC_CHECK_VERSION(4,7)
+constexpr
+#endif
+static inline const C &
+ContainerCast(const A &a, A C::*member)
+{
+	return *OffsetCast<const C, const A>(&a, ContainerAttributeOffset<C, A>(member));
+}
+
 #endif