github.com/searKing/golang/go@v1.2.117/runtime/cgosymbolizer/include/boost/core/enable_if.hpp (about)

     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_CORE_ENABLE_IF_HPP
    15  #define BOOST_CORE_ENABLE_IF_HPP
    16  
    17  #include "boost/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 boost
    25  {
    26    template<typename T, typename R=void>
    27    struct enable_if_has_type
    28    {
    29      typedef R type;
    30    };
    31   
    32    template <bool B, class T = void>
    33    struct enable_if_c {
    34      typedef T type;
    35    };
    36  
    37    template <class T>
    38    struct enable_if_c<false, T> {};
    39  
    40    template <class Cond, class T = void> 
    41    struct enable_if : public enable_if_c<Cond::value, T> {};
    42  
    43    template <bool B, class T>
    44    struct lazy_enable_if_c {
    45      typedef typename T::type type;
    46    };
    47  
    48    template <class T>
    49    struct lazy_enable_if_c<false, T> {};
    50  
    51    template <class Cond, class T> 
    52    struct lazy_enable_if : public lazy_enable_if_c<Cond::value, T> {};
    53  
    54  
    55    template <bool B, class T = void>
    56    struct disable_if_c {
    57      typedef T type;
    58    };
    59  
    60    template <class T>
    61    struct disable_if_c<true, T> {};
    62  
    63    template <class Cond, class T = void> 
    64    struct disable_if : public disable_if_c<Cond::value, T> {};
    65  
    66    template <bool B, class T>
    67    struct lazy_disable_if_c {
    68      typedef typename T::type type;
    69    };
    70  
    71    template <class T>
    72    struct lazy_disable_if_c<true, T> {};
    73  
    74    template <class Cond, class T> 
    75    struct lazy_disable_if : public lazy_disable_if_c<Cond::value, T> {};
    76  
    77  } // namespace boost
    78  
    79  #else
    80  
    81  namespace boost {
    82  
    83    namespace detail { typedef void enable_if_default_T; }
    84  
    85    template <typename T>
    86    struct enable_if_does_not_work_on_this_compiler;
    87  
    88    template<typename T, typename R=void>
    89    struct enable_if_has_type : enable_if_does_not_work_on_this_compiler<T>
    90    { };
    91  
    92    template <bool B, class T = detail::enable_if_default_T>
    93    struct enable_if_c : enable_if_does_not_work_on_this_compiler<T>
    94    { };
    95  
    96    template <bool B, class T = detail::enable_if_default_T> 
    97    struct disable_if_c : enable_if_does_not_work_on_this_compiler<T>
    98    { };
    99  
   100    template <bool B, class T = detail::enable_if_default_T> 
   101    struct lazy_enable_if_c : enable_if_does_not_work_on_this_compiler<T>
   102    { };
   103  
   104    template <bool B, class T = detail::enable_if_default_T> 
   105    struct lazy_disable_if_c : enable_if_does_not_work_on_this_compiler<T>
   106    { };
   107  
   108    template <class Cond, class T = detail::enable_if_default_T> 
   109    struct enable_if : enable_if_does_not_work_on_this_compiler<T>
   110    { };
   111  
   112    template <class Cond, class T = detail::enable_if_default_T> 
   113    struct disable_if : enable_if_does_not_work_on_this_compiler<T>
   114    { };
   115  
   116    template <class Cond, class T = detail::enable_if_default_T> 
   117    struct lazy_enable_if : enable_if_does_not_work_on_this_compiler<T>
   118    { };
   119  
   120    template <class Cond, class T = detail::enable_if_default_T> 
   121    struct lazy_disable_if : enable_if_does_not_work_on_this_compiler<T>
   122    { };
   123  
   124  } // namespace boost
   125  
   126  #endif // BOOST_NO_SFINAE
   127  
   128  #endif