result_of_variadic.hpp 5.5 KB

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  1. // Boost result_of library
  2. // Copyright Douglas Gregor 2004. Use, modification and
  3. // distribution is subject to the Boost Software License, Version
  4. // 1.0. (See accompanying file LICENSE_1_0.txt or copy at
  5. // http://www.boost.org/LICENSE_1_0.txt)
  6. // Copyright Daniel Walker, Eric Niebler, Michel Morin 2008-2012.
  7. // Use, modification and distribution is subject to the Boost Software
  8. // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or
  9. // copy at http://www.boost.org/LICENSE_1_0.txt)
  10. // For more information, see http://www.boost.org/libs/utility
  11. #ifndef BOOST_RESULT_OF_HPP
  12. # error Boost result_of - do not include this file!
  13. #endif
  14. template<typename F, typename... Args>
  15. struct tr1_result_of<F(Args...)>
  16. : conditional<
  17. is_pointer<F>::value || is_member_function_pointer<F>::value
  18. , boost::detail::tr1_result_of_impl<
  19. typename remove_cv<F>::type,
  20. typename remove_cv<F>::type(Args...),
  21. (boost::detail::result_of_has_result_type<F>::value)>
  22. , boost::detail::tr1_result_of_impl<
  23. F,
  24. F(Args...),
  25. (boost::detail::result_of_has_result_type<F>::value)> >::type { };
  26. #ifdef BOOST_RESULT_OF_USE_DECLTYPE
  27. template<typename F, typename... Args>
  28. struct result_of<F(Args...)>
  29. : detail::cpp0x_result_of<F(Args...)> { };
  30. #endif // BOOST_RESULT_OF_USE_DECLTYPE
  31. #ifdef BOOST_RESULT_OF_USE_TR1_WITH_DECLTYPE_FALLBACK
  32. template<typename F, typename... Args>
  33. struct result_of<F(Args...)>
  34. : conditional<detail::result_of_has_result_type<F>::value || detail::result_of_has_result<F>::value,
  35. tr1_result_of<F(Args...)>,
  36. detail::cpp0x_result_of<F(Args...)> >::type { };
  37. #endif // BOOST_RESULT_OF_USE_TR1_WITH_DECLTYPE_FALLBACK
  38. #if defined(BOOST_RESULT_OF_USE_DECLTYPE) || defined(BOOST_RESULT_OF_USE_TR1_WITH_DECLTYPE_FALLBACK)
  39. namespace detail {
  40. template<typename F, typename... Args>
  41. struct cpp0x_result_of<F(Args...)>
  42. : conditional<
  43. is_member_function_pointer<F>::value
  44. , detail::tr1_result_of_impl<
  45. typename remove_cv<F>::type,
  46. typename remove_cv<F>::type(Args...), false
  47. >
  48. , detail::cpp0x_result_of_impl<
  49. F(Args...)
  50. >
  51. >::type
  52. {};
  53. #ifdef BOOST_NO_SFINAE_EXPR
  54. template<typename F>
  55. struct result_of_callable_fun_2;
  56. template<typename R, typename... Args>
  57. struct result_of_callable_fun_2<R(Args...)> {
  58. R operator()(Args...) const;
  59. typedef result_of_private_type const &(*pfn_t)(...);
  60. operator pfn_t() const volatile;
  61. };
  62. template<typename F>
  63. struct result_of_callable_fun
  64. : result_of_callable_fun_2<F>
  65. {};
  66. template<typename F>
  67. struct result_of_callable_fun<F *>
  68. : result_of_callable_fun_2<F>
  69. {};
  70. template<typename F>
  71. struct result_of_select_call_wrapper_type
  72. : conditional<
  73. is_class<typename remove_reference<F>::type>::value,
  74. result_of_wrap_callable_class<F>,
  75. type_identity<result_of_callable_fun<typename remove_cv<typename remove_reference<F>::type>::type> >
  76. >::type
  77. {};
  78. template<typename F, typename... Args>
  79. struct result_of_is_callable {
  80. typedef typename result_of_select_call_wrapper_type<F>::type wrapper_t;
  81. static const bool value = (
  82. sizeof(result_of_no_type) == sizeof(detail::result_of_is_private_type(
  83. (boost::declval<wrapper_t>()(boost::declval<Args>()...), result_of_weird_type())
  84. ))
  85. );
  86. typedef integral_constant<bool, value> type;
  87. };
  88. template<typename F, typename... Args>
  89. struct cpp0x_result_of_impl<F(Args...), true>
  90. : lazy_enable_if<
  91. result_of_is_callable<F, Args...>
  92. , cpp0x_result_of_impl<F(Args...), false>
  93. >
  94. {};
  95. template<typename F, typename... Args>
  96. struct cpp0x_result_of_impl<F(Args...), false>
  97. {
  98. typedef decltype(
  99. boost::declval<F>()(
  100. boost::declval<Args>()...
  101. )
  102. ) type;
  103. };
  104. #else // BOOST_NO_SFINAE_EXPR
  105. template<typename F, typename... Args>
  106. struct cpp0x_result_of_impl<F(Args...),
  107. typename result_of_always_void<decltype(
  108. boost::declval<F>()(
  109. boost::declval<Args>()...
  110. )
  111. )>::type> {
  112. typedef decltype(
  113. boost::declval<F>()(
  114. boost::declval<Args>()...
  115. )
  116. ) type;
  117. };
  118. #endif // BOOST_NO_SFINAE_EXPR
  119. } // namespace detail
  120. #else // defined(BOOST_RESULT_OF_USE_DECLTYPE) || defined(BOOST_RESULT_OF_USE_TR1_WITH_DECLTYPE_FALLBACK)
  121. template<typename F, typename... Args>
  122. struct result_of<F(Args...)>
  123. : tr1_result_of<F(Args...)> { };
  124. #endif // defined(BOOST_RESULT_OF_USE_DECLTYPE)
  125. namespace detail {
  126. template<typename R, typename FArgs, typename... Args>
  127. struct tr1_result_of_impl<R (*)(Args...), FArgs, false>
  128. {
  129. typedef R type;
  130. };
  131. template<typename R, typename FArgs, typename... Args>
  132. struct tr1_result_of_impl<R (&)(Args...), FArgs, false>
  133. {
  134. typedef R type;
  135. };
  136. template<typename R, typename FArgs, typename C, typename... Args>
  137. struct tr1_result_of_impl<R (C::*)(Args...), FArgs, false>
  138. {
  139. typedef R type;
  140. };
  141. template<typename R, typename FArgs, typename C, typename... Args>
  142. struct tr1_result_of_impl<R (C::*)(Args...) const, FArgs, false>
  143. {
  144. typedef R type;
  145. };
  146. template<typename R, typename FArgs, typename C, typename... Args>
  147. struct tr1_result_of_impl<R (C::*)(Args...) volatile, FArgs, false>
  148. {
  149. typedef R type;
  150. };
  151. template<typename R, typename FArgs, typename C, typename... Args>
  152. struct tr1_result_of_impl<R (C::*)(Args...) const volatile, FArgs, false>
  153. {
  154. typedef R type;
  155. };
  156. }