| Jeff Thompson | a28eed8 | 2013-08-22 16:21:10 -0700 | [diff] [blame^] | 1 | // Boost enable_if library |
| 2 | |
| 3 | // Copyright 2003 (c) The Trustees of Indiana University. |
| 4 | |
| 5 | // Use, modification, and distribution is subject to the Boost Software |
| 6 | // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at |
| 7 | // http://www.boost.org/LICENSE_1_0.txt) |
| 8 | |
| 9 | // Authors: Jaakko Jarvi (jajarvi at osl.iu.edu) |
| 10 | // Jeremiah Willcock (jewillco at osl.iu.edu) |
| 11 | // Andrew Lumsdaine (lums at osl.iu.edu) |
| 12 | |
| 13 | |
| 14 | #ifndef BOOST_UTILITY_ENABLE_IF_HPP |
| 15 | #define BOOST_UTILITY_ENABLE_IF_HPP |
| 16 | |
| 17 | #include "ndnboost/config.hpp" |
| 18 | |
| 19 | // Even the definition of enable_if causes problems on some compilers, |
| 20 | // so it's macroed out for all compilers that do not support SFINAE |
| 21 | |
| 22 | #ifndef BOOST_NO_SFINAE |
| 23 | |
| 24 | namespace ndnboost |
| 25 | { |
| 26 | |
| 27 | template <bool B, class T = void> |
| 28 | struct enable_if_c { |
| 29 | typedef T type; |
| 30 | }; |
| 31 | |
| 32 | template <class T> |
| 33 | struct enable_if_c<false, T> {}; |
| 34 | |
| 35 | template <class Cond, class T = void> |
| 36 | struct enable_if : public enable_if_c<Cond::value, T> {}; |
| 37 | |
| 38 | template <bool B, class T> |
| 39 | struct lazy_enable_if_c { |
| 40 | typedef typename T::type type; |
| 41 | }; |
| 42 | |
| 43 | template <class T> |
| 44 | struct lazy_enable_if_c<false, T> {}; |
| 45 | |
| 46 | template <class Cond, class T> |
| 47 | struct lazy_enable_if : public lazy_enable_if_c<Cond::value, T> {}; |
| 48 | |
| 49 | |
| 50 | template <bool B, class T = void> |
| 51 | struct disable_if_c { |
| 52 | typedef T type; |
| 53 | }; |
| 54 | |
| 55 | template <class T> |
| 56 | struct disable_if_c<true, T> {}; |
| 57 | |
| 58 | template <class Cond, class T = void> |
| 59 | struct disable_if : public disable_if_c<Cond::value, T> {}; |
| 60 | |
| 61 | template <bool B, class T> |
| 62 | struct lazy_disable_if_c { |
| 63 | typedef typename T::type type; |
| 64 | }; |
| 65 | |
| 66 | template <class T> |
| 67 | struct lazy_disable_if_c<true, T> {}; |
| 68 | |
| 69 | template <class Cond, class T> |
| 70 | struct lazy_disable_if : public lazy_disable_if_c<Cond::value, T> {}; |
| 71 | |
| 72 | } // namespace ndnboost |
| 73 | |
| 74 | #else |
| 75 | |
| 76 | namespace ndnboost { |
| 77 | |
| 78 | namespace detail { typedef void enable_if_default_T; } |
| 79 | |
| 80 | template <typename T> |
| 81 | struct enable_if_does_not_work_on_this_compiler; |
| 82 | |
| 83 | template <bool B, class T = detail::enable_if_default_T> |
| 84 | struct enable_if_c : enable_if_does_not_work_on_this_compiler<T> |
| 85 | { }; |
| 86 | |
| 87 | template <bool B, class T = detail::enable_if_default_T> |
| 88 | struct disable_if_c : enable_if_does_not_work_on_this_compiler<T> |
| 89 | { }; |
| 90 | |
| 91 | template <bool B, class T = detail::enable_if_default_T> |
| 92 | struct lazy_enable_if_c : enable_if_does_not_work_on_this_compiler<T> |
| 93 | { }; |
| 94 | |
| 95 | template <bool B, class T = detail::enable_if_default_T> |
| 96 | struct lazy_disable_if_c : enable_if_does_not_work_on_this_compiler<T> |
| 97 | { }; |
| 98 | |
| 99 | template <class Cond, class T = detail::enable_if_default_T> |
| 100 | struct enable_if : enable_if_does_not_work_on_this_compiler<T> |
| 101 | { }; |
| 102 | |
| 103 | template <class Cond, class T = detail::enable_if_default_T> |
| 104 | struct disable_if : enable_if_does_not_work_on_this_compiler<T> |
| 105 | { }; |
| 106 | |
| 107 | template <class Cond, class T = detail::enable_if_default_T> |
| 108 | struct lazy_enable_if : enable_if_does_not_work_on_this_compiler<T> |
| 109 | { }; |
| 110 | |
| 111 | template <class Cond, class T = detail::enable_if_default_T> |
| 112 | struct lazy_disable_if : enable_if_does_not_work_on_this_compiler<T> |
| 113 | { }; |
| 114 | |
| 115 | } // namespace ndnboost |
| 116 | |
| 117 | #endif // BOOST_NO_SFINAE |
| 118 | |
| 119 | #endif |