boost/qvm/enable_if.hpp

0001 #ifndef BOOST_QVM_ENABLE_IF_HPP_INCLUDED
0002 #define BOOST_QVM_ENABLE_IF_HPP_INCLUDED
0003
0004 // Copyright 2008-2022 Emil Dotchevski and Reverge Studios, Inc.
0005
0006 // Distributed under the Boost Software License, Version 1.0. (See accompanying
0007 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0008
0009 // Boost enable_if library
0010
0011 // Copyright 2003 (c) The Trustees of Indiana University.
0012
0013 //    Authors: Jaakko Jarvi (jajarvi at osl.iu.edu)
0014 //             Jeremiah Willcock (jewillco at osl.iu.edu)
0015 //             Andrew Lumsdaine (lums at osl.iu.edu)
0016
0017 namespace boost { namespace qvm {
0018
0019   template<typename T, typename R=void>
0020   struct enable_if_has_type
0021   {
0022     typedef R type;
0023   };
0024
0025   template <bool B, class T = void>
0026   struct enable_if_c {
0027     typedef T type;
0028   };
0029
0030   template <class T>
0031   struct enable_if_c<false, T> {};
0032
0033   template <class Cond, class T = void>
0034   struct enable_if : public enable_if_c<Cond::value, T> {};
0035
0036   template <bool B, class T>
0037   struct lazy_enable_if_c {
0038     typedef typename T::type type;
0039   };
0040
0041   template <class T>
0042   struct lazy_enable_if_c<false, T> {};
0043
0044   template <class Cond, class T>
0045   struct lazy_enable_if : public lazy_enable_if_c<Cond::value, T> {};
0046
0047
0048   template <bool B, class T = void>
0049   struct disable_if_c {
0050     typedef T type;
0051   };
0052
0053   template <class T>
0054   struct disable_if_c<true, T> {};
0055
0056   template <class Cond, class T = void>
0057   struct disable_if : public disable_if_c<Cond::value, T> {};
0058
0059   template <bool B, class T>
0060   struct lazy_disable_if_c {
0061     typedef typename T::type type;
0062   };
0063
0064   template <class T>
0065   struct lazy_disable_if_c<true, T> {};
0066
0067   template <class Cond, class T>
0068   struct lazy_disable_if : public lazy_disable_if_c<Cond::value, T> {};
0069
0070 ////////////////////////////////////////////////
0071
0072   // The types below are a copy of the original types above, to workaround MSVC-12 bugs.
0073
0074   template<typename T, typename R=void>
0075   struct enable_if_has_type2
0076   {
0077     typedef R type;
0078   };
0079
0080   template <bool B, class T = void>
0081   struct enable_if_c2 {
0082     typedef T type;
0083   };
0084
0085   template <class T>
0086   struct enable_if_c2<false, T> {};
0087
0088   template <class Cond, class T = void>
0089   struct enable_if2 : public enable_if_c2<Cond::value, T> {};
0090
0091   template <bool B, class T>
0092   struct lazy_enable_if_c2 {
0093     typedef typename T::type type;
0094   };
0095
0096   template <class T>
0097   struct lazy_enable_if_c2<false, T> {};
0098
0099   template <class Cond, class T>
0100   struct lazy_enable_if2 : public lazy_enable_if_c2<Cond::value, T> {};
0101
0102
0103   template <bool B, class T = void>
0104   struct disable_if_c2 {
0105     typedef T type;
0106   };
0107
0108   template <class T>
0109   struct disable_if_c2<true, T> {};
0110
0111   template <class Cond, class T = void>
0112   struct disable_if2 : public disable_if_c2<Cond::value, T> {};
0113
0114   template <bool B, class T>
0115   struct lazy_disable_if_c2 {
0116     typedef typename T::type type;
0117   };
0118
0119   template <class T>
0120   struct lazy_disable_if_c2<true, T> {};
0121
0122   template <class Cond, class T>
0123   struct lazy_disable_if2 : public lazy_disable_if_c2<Cond::value, T> {};
0124
0125 } }
0126
0127 #endif