alloc/easy: add move initialisation for array allocations

alloc/easy.hpp

@@ -3,7 +3,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  *
- * Copyright 2018 Danny Robson <danny@nerdcruft.net>
+ * Copyright 2018-2020, Danny Robson <danny@nerdcruft.net>
  */
 
 #pragma once
@@ -11,9 +11,10 @@
 
 #include "traits.hpp"
 
+#include "../buffer/traits.hpp"
+#include "../concepts.hpp"
 #include "../std.hpp"
 #include "../view.hpp"
-#include "../buffer/traits.hpp"
 
 #include <utility>
 #include <memory>
@@ -159,6 +160,26 @@ namespace cruft::alloc::easy {
         }
 
 
+        /// Allocates storage for an array of ValueT, moves the values from
+        /// ContainerT into this storage, and returns a view over the memory.
+        template <
+            concepts::iterable ContainerT
+        >
+        auto
+        array (ContainerT &&container)
+        {
+            using IteratorT = decltype (std::begin (container));
+            using ValueT = typename std::iterator_traits<IteratorT>::value_type;
+
+            auto store = array<ValueT> (std::size (container));
+            std::copy (
+                std::move_iterator (std::begin (container)),
+                std::move_iterator (std::end   (container)),
+                std::begin (store)
+            );
+
+            return store;
+        }
 
 
         /// Create an object of type `U` using `acquire` and wrap the result