Add SCons configure checks

[senf.git] / boost_ext / boost / multi_index / detail / auto_space.hpp

diff --git a/boost_ext/boost/multi_index/detail/auto_space.hpp b/boost_ext/boost/multi_index/detail/auto_space.hpp
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+/* Copyright 2003-2007 Joaquín M López Muñoz.
+ * 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/multi_index for library home page.
+ */
+
+#ifndef BOOST_MULTI_INDEX_DETAIL_AUTO_SPACE_HPP
+#define BOOST_MULTI_INDEX_DETAIL_AUTO_SPACE_HPP
+
+#if defined(_MSC_VER)&&(_MSC_VER>=1200)
+#pragma once
+#endif
+
+#include <boost/config.hpp> /* keep it first to prevent nasty warns in MSVC */
+#include <algorithm>
+#include <boost/detail/allocator_utilities.hpp>
+#include <boost/multi_index/detail/adl_swap.hpp>
+#include <boost/multi_index/detail/prevent_eti.hpp>
+#include <boost/noncopyable.hpp>
+#include <memory>
+
+namespace boost{
+
+namespace multi_index{
+
+namespace detail{
+
+/* auto_space provides uninitialized space suitably to store
+ * a given number of elements of a given type.
+ */
+
+/* NB: it is not clear whether using an allocator to handle
+ * zero-sized arrays of elements is conformant or not. GCC 3.3.1
+ * and prior fail here, other stdlibs handle the issue gracefully.
+ * To be on the safe side, the case n==0 is given special treatment.
+ * References:
+ *   GCC Bugzilla, "standard allocator crashes when deallocating segment
+ *    "of zero length", http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14176
+ *   C++ Standard Library Defect Report List (Revision 28), issue 199
+ *     "What does allocate(0) return?",
+ *     http://anubis.dkuug.dk/jtc1/sc22/wg21/docs/lwg-defects.html#199
+ */
+
+template<typename T,typename Allocator=std::allocator<T> >
+struct auto_space:private noncopyable
+{
+  typedef typename prevent_eti<
+    Allocator,
+    typename boost::detail::allocator::rebind_to<
+      Allocator,T
+    >::type
+  >::type::pointer pointer;
+
+  explicit auto_space(const Allocator& al=Allocator(),std::size_t n=1):
+  al_(al),n_(n),data_(n_?al_.allocate(n_):pointer(0))
+  {}
+
+  ~auto_space()
+  {
+    if(n_)al_.deallocate(data_,n_);
+  }
+
+  Allocator get_allocator()const{return al_;}
+
+  pointer data()const{return data_;}
+
+  void swap(auto_space& x)
+  {
+    if(al_!=x.al_)adl_swap(al_,x.al_);
+    std::swap(n_,x.n_);
+    std::swap(data_,x.data_);
+  }
+    
+private:
+  typename boost::detail::allocator::rebind_to<
+    Allocator,T>::type                          al_;
+  std::size_t                                   n_;
+  pointer                                       data_;
+};
+
+template<typename T,typename Allocator>
+void swap(auto_space<T,Allocator>& x,auto_space<T,Allocator>& y)
+{
+  x.swap(y);
+}
+
+} /* namespace multi_index::detail */
+
+} /* namespace multi_index */
+
+} /* namespace boost */
+
+#endif