ceph/src/boost/libs/core/include/boost/core/underlying_type.hpp

   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