Imported Upstream version 1.57.0upstream/1.57.0

1 files changed, 72 insertions, 0 deletions

diff --git a/boost/move/traits.hpp b/boost/move/traits.hpp
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+//////////////////////////////////////////////////////////////////////////////
+//
+// (C) Copyright Ion Gaztanaga 2009-2012.
+// 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)
+//
+// See http://www.boost.org/libs/move for documentation.
+//
+//////////////////////////////////////////////////////////////////////////////
+
+//! \file
+
+#ifndef BOOST_MOVE_MOVE_TRAITS_HPP
+#define BOOST_MOVE_MOVE_TRAITS_HPP
+
+#include <boost/move/detail/config_begin.hpp>
+#include <boost/type_traits/has_trivial_destructor.hpp>
+#include <boost/type_traits/is_nothrow_move_constructible.hpp>
+#include <boost/type_traits/is_nothrow_move_assignable.hpp>
+#include <boost/type_traits/is_copy_constructible.hpp>
+#include <boost/move/detail/meta_utils.hpp>
+
+#ifndef BOOST_NO_CXX11_RVALUE_REFERENCES
+#include <boost/move/core.hpp>
+#endif
+
+namespace boost {
+
+//! If this trait yields to true
+//! (<i>has_trivial_destructor_after_move &lt;T&gt;::value == true</i>)
+//! means that if T is used as argument of a move construction/assignment,
+//! there is no need to call T's destructor.
+//! This optimization tipically is used to improve containers' performance.
+//!
+//! By default this trait is true if the type has trivial destructor,
+//! every class should specialize this trait if it wants to improve performance
+//! when inserted in containers.
+template <class T>
+struct has_trivial_destructor_after_move
+   : ::boost::has_trivial_destructor<T>
+{};
+
+//! By default this traits returns
+//! <pre>boost::is_nothrow_move_constructible<T>::value && boost::is_nothrow_move_assignable<T>::value </pre>.
+//! Classes with non-throwing move constructor
+//! and assignment can specialize this trait to obtain some performance improvements.
+template <class T>
+struct has_nothrow_move
+{
+   static const bool value = boost::is_nothrow_move_constructible<T>::value &&
+                             boost::is_nothrow_move_assignable<T>::value;
+};
+
+namespace move_detail {
+
+template <class T>
+struct is_nothrow_move_constructible_or_uncopyable
+{
+   //The standard requires is_nothrow_move_constructible for move_if_noexcept
+   //but a user (usually in C++03) might specialize has_nothrow_move which includes it
+   static const bool value = boost::is_nothrow_move_constructible<T>::value ||
+                             has_nothrow_move<T>::value ||
+                            !boost::is_copy_constructible<T>::value;
+};
+
+}  //move_detail {
+}  //namespace boost {
+
+#include <boost/move/detail/config_end.hpp>
+
+#endif //#ifndef BOOST_MOVE_MOVE_TRAITS_HPP