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1 | // (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com) |
2 | // (C) Copyright 2003-2007 Jonathan Turkanis | |
3 | // Distributed under the Boost Software License, Version 1.0. (See accompanying | |
4 | // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.) | |
5 | ||
6 | // See http://www.boost.org/libs/iostreams for documentation. | |
7 | ||
8 | #ifndef BOOST_IOSTREAMS_DETAIL_WRAP_UNWRAP_HPP_INCLUDED | |
9 | #define BOOST_IOSTREAMS_DETAIL_WRAP_UNWRAP_HPP_INCLUDED | |
10 | ||
11 | #if defined(_MSC_VER) | |
12 | # pragma once | |
13 | #endif | |
14 | ||
15 | #include <boost/config.hpp> // SFINAE, MSVC. | |
16 | #include <boost/detail/workaround.hpp> | |
17 | #include <boost/iostreams/detail/enable_if_stream.hpp> | |
18 | #include <boost/iostreams/traits_fwd.hpp> // is_std_io. | |
19 | #include <boost/mpl/bool.hpp> | |
20 | #include <boost/mpl/identity.hpp> | |
21 | #include <boost/mpl/eval_if.hpp> | |
22 | #include <boost/mpl/if.hpp> | |
23 | #include <boost/ref.hpp> | |
24 | ||
25 | namespace boost { namespace iostreams { namespace detail { | |
26 | ||
27 | //------------------Definition of wrap/unwrap traits--------------------------// | |
28 | ||
29 | template<typename T> | |
30 | struct wrapped_type | |
31 | : mpl::if_<is_std_io<T>, reference_wrapper<T>, T> | |
32 | { }; | |
33 | ||
34 | template<typename T> | |
35 | struct unwrapped_type | |
36 | : unwrap_reference<T> | |
37 | { }; | |
38 | ||
39 | template<typename T> | |
40 | struct unwrap_ios | |
41 | : mpl::eval_if< | |
42 | is_std_io<T>, | |
43 | unwrap_reference<T>, | |
44 | mpl::identity<T> | |
45 | > | |
46 | { }; | |
47 | ||
48 | //------------------Definition of wrap----------------------------------------// | |
49 | ||
50 | #ifndef BOOST_NO_SFINAE //----------------------------------------------------// | |
51 | template<typename T> | |
52 | inline T wrap(const T& t BOOST_IOSTREAMS_DISABLE_IF_STREAM(T)) | |
53 | { return t; } | |
54 | ||
55 | template<typename T> | |
56 | inline typename wrapped_type<T>::type | |
57 | wrap(T& t BOOST_IOSTREAMS_ENABLE_IF_STREAM(T)) { return boost::ref(t); } | |
58 | #else // #ifndef BOOST_NO_SFINAE //-------------------------------------------// | |
59 | template<typename T> | |
60 | inline typename wrapped_type<T>::type // BCC 5.x needs namespace qualification. | |
61 | wrap_impl(const T& t, mpl::true_) { return boost::ref(const_cast<T&>(t)); } | |
62 | ||
63 | template<typename T> | |
64 | inline typename wrapped_type<T>::type // BCC 5.x needs namespace qualification. | |
65 | wrap_impl(T& t, mpl::true_) { return boost::ref(t); } | |
66 | ||
67 | template<typename T> | |
68 | inline typename wrapped_type<T>::type | |
69 | wrap_impl(const T& t, mpl::false_) { return t; } | |
70 | ||
71 | template<typename T> | |
72 | inline typename wrapped_type<T>::type | |
73 | wrap_impl(T& t, mpl::false_) { return t; } | |
74 | ||
75 | template<typename T> | |
76 | inline typename wrapped_type<T>::type | |
77 | wrap(const T& t) { return wrap_impl(t, is_std_io<T>()); } | |
78 | ||
79 | template<typename T> | |
80 | inline typename wrapped_type<T>::type | |
81 | wrap(T& t) { return wrap_impl(t, is_std_io<T>()); } | |
82 | #endif // #ifndef BOOST_NO_SFINAE //------------------------------------------// | |
83 | ||
84 | //------------------Definition of unwrap--------------------------------------// | |
85 | ||
86 | template<typename T> | |
87 | typename unwrapped_type<T>::type& | |
88 | unwrap(const reference_wrapper<T>& ref) { return ref.get(); } | |
89 | ||
90 | template<typename T> | |
91 | typename unwrapped_type<T>::type& unwrap(T& t) { return t; } | |
92 | ||
93 | template<typename T> | |
94 | const typename unwrapped_type<T>::type& unwrap(const T& t) { return t; } | |
95 | ||
96 | } } } // End namespaces detail, iostreams, boost. | |
97 | ||
98 | #endif // #ifndef BOOST_IOSTREAMS_DETAIL_WRAP_UNWRAP_HPP_INCLUDED |