| 1 | // underlying_type.hpp ---------------------------------------------------------// |
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| 2 | |
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| 3 | // Copyright Beman Dawes, 2009 |
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| 4 | // Copyright (C) 2011-2012 Vicente J. Botet Escriba |
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| 5 | // Copyright (C) 2012 Anthony Williams |
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| 6 | // Copyright (C) 2014 Andrey Semashev |
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| 7 | |
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| 8 | // Distributed under the Boost Software License, Version 1.0. |
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| 9 | // See http://www.boost.org/LICENSE_1_0.txt |
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| 10 | |
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| 11 | #ifndef BOOST_CORE_UNDERLYING_TYPE_HPP |
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| 12 | #define BOOST_CORE_UNDERLYING_TYPE_HPP |
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| 13 | |
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| 14 | #include <boost/config.hpp> |
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| 15 | |
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| 16 | // GCC 4.7 and later seem to provide std::underlying_type |
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| 17 | #if !defined(BOOST_NO_CXX11_HDR_TYPE_TRAITS) || (defined(BOOST_GCC) && BOOST_GCC >= 40700 && defined(__GXX_EXPERIMENTAL_CXX0X__)) |
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| 18 | #include <type_traits> |
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| 19 | #define BOOST_DETAIL_HAS_STD_UNDERLYING_TYPE |
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| 20 | #endif |
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| 21 | |
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| 22 | #ifdef BOOST_HAS_PRAGMA_ONCE |
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| 23 | #pragma once |
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| 24 | #endif |
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| 25 | |
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| 26 | namespace boost { |
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| 27 | |
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| 28 | namespace detail { |
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| 29 | |
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| 30 | template< typename EnumType, typename Void = void > |
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| 31 | struct underlying_type_impl; |
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| 32 | |
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| 33 | #if defined(BOOST_NO_CXX11_SCOPED_ENUMS) |
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| 34 | |
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| 35 | // Support for boost/core/scoped_enum.hpp |
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| 36 | template< typename EnumType > |
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| 37 | struct underlying_type_impl< EnumType, typename EnumType::is_boost_scoped_enum_tag > |
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| 38 | { |
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| 39 | /** |
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| 40 | * The member typedef type names the underlying type of EnumType. It is EnumType::underlying_type when the EnumType is an emulated scoped enum, |
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| 41 | */ |
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| 42 | typedef typename EnumType::underlying_type type; |
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| 43 | }; |
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| 44 | |
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| 45 | #endif |
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| 46 | |
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| 47 | #if defined(BOOST_DETAIL_HAS_STD_UNDERLYING_TYPE) |
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| 48 | |
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| 49 | template< typename EnumType, typename Void > |
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| 50 | struct underlying_type_impl |
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| 51 | { |
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| 52 | typedef typename std::underlying_type< EnumType >::type type; |
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| 53 | }; |
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| 54 | |
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| 55 | #endif |
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| 56 | |
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| 57 | } // namespace detail |
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| 58 | |
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| 59 | #if !defined(BOOST_NO_CXX11_SCOPED_ENUMS) && !defined(BOOST_DETAIL_HAS_STD_UNDERLYING_TYPE) |
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| 60 | #define BOOST_NO_UNDERLYING_TYPE |
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| 61 | #endif |
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| 62 | |
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| 63 | /** |
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| 64 | * Meta-function to get the underlying type of a scoped enum. |
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| 65 | * |
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| 66 | * Requires EnumType must be an enum type or the emulation of a scoped enum. |
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| 67 | * If BOOST_NO_UNDERLYING_TYPE is defined, the implementation will not be able |
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| 68 | * to deduce the underlying type of enums. The user is expected to specialize |
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| 69 | * this trait in this case. |
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| 70 | */ |
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| 71 | template< typename EnumType > |
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| 72 | struct underlying_type : |
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| 73 | public detail::underlying_type_impl< EnumType > |
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| 74 | { |
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| 75 | }; |
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| 76 | |
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| 77 | } // namespace boost |
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| 78 | |
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| 79 | #endif // BOOST_CORE_UNDERLYING_TYPE_HPP |
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| 80 | |
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