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1 | // underlying_type.hpp ---------------------------------------------------------// |
2 | ||
3 | // Copyright Beman Dawes, 2009 | |
4 | // Copyright (C) 2011-2012 Vicente J. Botet Escriba | |
5 | // Copyright (C) 2012 Anthony Williams | |
6 | // Copyright (C) 2014 Andrey Semashev | |
7 | ||
8 | // Distributed under the Boost Software License, Version 1.0. | |
9 | // See http://www.boost.org/LICENSE_1_0.txt | |
10 | ||
11 | #ifndef BOOST_CORE_UNDERLYING_TYPE_HPP | |
12 | #define BOOST_CORE_UNDERLYING_TYPE_HPP | |
13 | ||
14 | #include <boost/config.hpp> | |
15 | ||
16 | // GCC 4.7 and later seem to provide std::underlying_type | |
17 | #if !defined(BOOST_NO_CXX11_HDR_TYPE_TRAITS) || (defined(BOOST_GCC) && BOOST_GCC >= 40700 && defined(__GXX_EXPERIMENTAL_CXX0X__)) | |
18 | #include <type_traits> | |
19 | #define BOOST_DETAIL_HAS_STD_UNDERLYING_TYPE | |
20 | #endif | |
21 | ||
22 | #ifdef BOOST_HAS_PRAGMA_ONCE | |
23 | #pragma once | |
24 | #endif | |
25 | ||
26 | namespace boost { | |
27 | ||
28 | namespace detail { | |
29 | ||
30 | template< typename EnumType, typename Void = void > | |
31 | struct underlying_type_impl; | |
32 | ||
33 | #if defined(BOOST_NO_CXX11_SCOPED_ENUMS) | |
34 | ||
35 | // Support for boost/core/scoped_enum.hpp | |
36 | template< typename EnumType > | |
37 | struct underlying_type_impl< EnumType, typename EnumType::is_boost_scoped_enum_tag > | |
38 | { | |
39 | /** | |
40 | * The member typedef type names the underlying type of EnumType. It is EnumType::underlying_type when the EnumType is an emulated scoped enum, | |
41 | */ | |
42 | typedef typename EnumType::underlying_type type; | |
43 | }; | |
44 | ||
45 | #endif | |
46 | ||
47 | #if defined(BOOST_DETAIL_HAS_STD_UNDERLYING_TYPE) | |
48 | ||
49 | template< typename EnumType, typename Void > | |
50 | struct underlying_type_impl | |
51 | { | |
52 | typedef typename std::underlying_type< EnumType >::type type; | |
53 | }; | |
54 | ||
55 | #endif | |
56 | ||
57 | } // namespace detail | |
58 | ||
59 | #if !defined(BOOST_NO_CXX11_SCOPED_ENUMS) && !defined(BOOST_DETAIL_HAS_STD_UNDERLYING_TYPE) | |
60 | #define BOOST_NO_UNDERLYING_TYPE | |
61 | #endif | |
62 | ||
63 | /** | |
64 | * Meta-function to get the underlying type of a scoped enum. | |
65 | * | |
66 | * Requires EnumType must be an enum type or the emulation of a scoped enum. | |
67 | * If BOOST_NO_UNDERLYING_TYPE is defined, the implementation will not be able | |
68 | * to deduce the underlying type of enums. The user is expected to specialize | |
69 | * this trait in this case. | |
70 | */ | |
71 | template< typename EnumType > | |
72 | struct underlying_type : | |
73 | public detail::underlying_type_impl< EnumType > | |
74 | { | |
75 | }; | |
76 | ||
77 | } // namespace boost | |
78 | ||
79 | #endif // BOOST_CORE_UNDERLYING_TYPE_HPP |