1// Copyright (C) 2007, 2008 Steven Watanabe, Joseph Gauterin, Niels Dekker
2//
3// Distributed under the Boost Software License, Version 1.0. (See
4// accompanying file LICENSE_1_0.txt or copy at
5// http://www.boost.org/LICENSE_1_0.txt)
6// For more information, see http://www.boost.org
7
8
9#ifndef BOOST_CORE_SWAP_HPP
10#define BOOST_CORE_SWAP_HPP
11
12// Note: the implementation of this utility contains various workarounds:
13// - swap_impl is put outside the boost namespace, to avoid infinite
14// recursion (causing stack overflow) when swapping objects of a primitive
15// type.
16// - swap_impl has a using-directive, rather than a using-declaration,
17// because some compilers (including MSVC 7.1, Borland 5.9.3, and
18// Intel 8.1) don't do argument-dependent lookup when it has a
19// using-declaration instead.
20// - boost::swap has two template arguments, instead of one, to
21// avoid ambiguity when swapping objects of a Boost type that does
22// not have its own boost::swap overload.
23
24#include <boost/core/enable_if.hpp>
25#include <boost/config.hpp>
26#include <utility> //for std::swap (C++11)
27#include <algorithm> //for std::swap (C++98)
28#include <cstddef> //for std::size_t
29
30namespace boost_swap_impl
31{
32 // we can't use type_traits here
33
34 template<class T> struct is_const { enum _vt { value = 0 }; };
35 template<class T> struct is_const<T const> { enum _vt { value = 1 }; };
36
37 template<class T>
38 BOOST_GPU_ENABLED
39 void swap_impl(T& left, T& right)
40 {
41 using namespace std;//use std::swap if argument dependent lookup fails
42 swap(left,right);
43 }
44
45 template<class T, std::size_t N>
46 BOOST_GPU_ENABLED
47 void swap_impl(T (& left)[N], T (& right)[N])
48 {
49 for (std::size_t i = 0; i < N; ++i)
50 {
51 ::boost_swap_impl::swap_impl(left[i], right[i]);
52 }
53 }
54}
55
56namespace boost
57{
58 template<class T1, class T2>
59 BOOST_GPU_ENABLED
60 typename enable_if_c< !boost_swap_impl::is_const<T1>::value && !boost_swap_impl::is_const<T2>::value >::type
61 swap(T1& left, T2& right)
62 {
63 ::boost_swap_impl::swap_impl(left, right);
64 }
65}
66
67#endif
68