Added thirdparty: boost library

thirdparty/include/boost/histogram/detail/array_wrapper.hpp

@@ -0,0 +1,66 @@
+// Copyright 2019 Hans Dembinski
+//
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt
+// or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_HISTOGRAM_DETAIL_ARRAY_WRAPPER_HPP
+#define BOOST_HISTOGRAM_DETAIL_ARRAY_WRAPPER_HPP
+
+#include <boost/core/make_span.hpp>
+#include <boost/core/nvp.hpp>
+#include <boost/histogram/detail/static_if.hpp>
+#include <boost/mp11/function.hpp>
+#include <boost/mp11/utility.hpp>
+#include <type_traits>
+
+namespace boost {
+namespace histogram {
+namespace detail {
+
+template <class T, class = decltype(&T::template save_array<int>)>
+struct has_save_array_impl;
+
+template <class T, class = decltype(&T::template load_array<int>)>
+struct has_load_array_impl;
+
+template <class T>
+using has_array_optimization = mp11::mp_or<mp11::mp_valid<has_save_array_impl, T>,
+                                           mp11::mp_valid<has_load_array_impl, T>>;
+
+template <class T>
+struct array_wrapper {
+  using pointer = T*;
+
+  pointer ptr;
+  std::size_t size;
+
+  template <class Archive>
+  void serialize(Archive& ar, unsigned /* version */) {
+    static_if_c<(has_array_optimization<Archive>::value &&
+                 std::is_trivially_copyable<T>::value)>(
+        [this](auto& ar) {
+          // cannot use and therefore bypass save_array / load_array interface, because
+          // it requires exact type boost::serialization::array_wrapper<T>
+          static_if_c<Archive::is_loading::value>(
+              [this](auto& ar) { ar.load_binary(this->ptr, sizeof(T) * this->size); },
+              [this](auto& ar) { ar.save_binary(this->ptr, sizeof(T) * this->size); },
+              ar);
+        },
+        [this](auto& ar) {
+          for (auto&& x : make_span(this->ptr, this->size)) ar& make_nvp("item", x);
+        },
+        ar);
+  }
+};
+
+template <class T>
+auto make_array_wrapper(T* t, std::size_t s) {
+  return array_wrapper<T>{t, s};
+}
+
+} // namespace detail
+} // namespace histogram
+} // namespace boost
+
+#endif