1 /* Copyright 2003-2007 Joaquín M López Muñoz.
2 * Distributed under the Boost Software License, Version 1.0.
3 * (See accompanying file LICENSE_1_0.txt or copy at
4 * http://www.boost.org/LICENSE_1_0.txt)
6 * See http://www.boost.org/libs/multi_index for library home page.
9 #ifndef BOOST_MULTI_INDEX_DETAIL_AUTO_SPACE_HPP
10 #define BOOST_MULTI_INDEX_DETAIL_AUTO_SPACE_HPP
12 #if defined(_MSC_VER)&&(_MSC_VER>=1200)
16 #include <boost/config.hpp> /* keep it first to prevent nasty warns in MSVC */
18 #include <boost/detail/allocator_utilities.hpp>
19 #include <boost/multi_index/detail/adl_swap.hpp>
20 #include <boost/multi_index/detail/prevent_eti.hpp>
21 #include <boost/noncopyable.hpp>
26 namespace multi_index{
30 /* auto_space provides uninitialized space suitably to store
31 * a given number of elements of a given type.
34 /* NB: it is not clear whether using an allocator to handle
35 * zero-sized arrays of elements is conformant or not. GCC 3.3.1
36 * and prior fail here, other stdlibs handle the issue gracefully.
37 * To be on the safe side, the case n==0 is given special treatment.
39 * GCC Bugzilla, "standard allocator crashes when deallocating segment
40 * "of zero length", http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14176
41 * C++ Standard Library Defect Report List (Revision 28), issue 199
42 * "What does allocate(0) return?",
43 * http://anubis.dkuug.dk/jtc1/sc22/wg21/docs/lwg-defects.html#199
46 template<typename T,typename Allocator=std::allocator<T> >
47 struct auto_space:private noncopyable
49 typedef typename prevent_eti<
51 typename boost::detail::allocator::rebind_to<
54 >::type::pointer pointer;
56 explicit auto_space(const Allocator& al=Allocator(),std::size_t n=1):
57 al_(al),n_(n),data_(n_?al_.allocate(n_):pointer(0))
62 if(n_)al_.deallocate(data_,n_);
65 Allocator get_allocator()const{return al_;}
67 pointer data()const{return data_;}
69 void swap(auto_space& x)
71 if(al_!=x.al_)adl_swap(al_,x.al_);
73 std::swap(data_,x.data_);
77 typename boost::detail::allocator::rebind_to<
78 Allocator,T>::type al_;
83 template<typename T,typename Allocator>
84 void swap(auto_space<T,Allocator>& x,auto_space<T,Allocator>& y)
89 } /* namespace multi_index::detail */
91 } /* namespace multi_index */
93 } /* namespace boost */