1: #pragma once

  3: #include <petsc/private/cpp/macros.hpp>
  4: #include <petsc/private/cpp/utility.hpp>
  5: #include <petsc/private/cpp/type_traits.hpp>
  6: #include <petsc/private/cpp/tuple.hpp>

  8: #include <functional>

 10: namespace Petsc
 11: {

 13: namespace util
 14: {

 16: namespace detail
 17: {

 19: struct can_call_test {
 20:   template <typename F, typename... A>
 21:   static decltype(std::declval<F>()(std::declval<A>()...), std::true_type()) f(int);

 23:   template <typename F, typename... A>
 24:   static std::false_type f(...);
 25: };

 27: // generic template
 28: template <typename T>
 29: struct func_traits_impl : func_traits_impl<decltype(&T::operator())> { };

 31: // function pointers
 32: template <typename Ret, typename... Args>
 33: struct func_traits_impl<Ret (*)(Args...)> {
 34:   using result_type = Ret;

 36:   template <std::size_t ix>
 37:   struct arg {
 38:     using type = util::tuple_element_t<ix, std::tuple<Args...>>;
 39:   };
 40: };

 42: // class-like operator()
 43: template <typename C, typename Ret, typename... Args>
 44: struct func_traits_impl<Ret (C::*)(Args...) const> {
 45:   using result_type = Ret;

 47:   template <std::size_t ix>
 48:   struct arg {
 49:     using type = util::tuple_element_t<ix, std::tuple<Args...>>;
 50:   };
 51: };

 53: template <typename C, typename Ret, typename... Args>
 54: struct func_traits_impl<Ret (C::*)(Args...)> {
 55:   using result_type = Ret;

 57:   template <std::size_t ix>
 58:   struct arg {
 59:     using type = util::tuple_element_t<ix, std::tuple<Args...>>;
 60:   };
 61: };

 63: } // namespace detail

 65: template <typename F, typename... A>
 66: struct can_call : decltype(detail::can_call_test::f<F, A...>(0)) { };

 68: template <typename... A, typename F>
 69: inline constexpr can_call<F, A...> is_callable_with(F &&) noexcept
 70: {
 71:   return can_call<F, A...>{};
 72: }

 74: template <typename T>
 75: struct func_traits : detail::func_traits_impl<decay_t<T>> {
 76:   template <std::size_t idx>
 77:   using arg_t = typename detail::func_traits_impl<decay_t<T>>::template arg<idx>::type;
 78: };

 80: } // namespace util

 82: } // namespace Petsc

 84: #define PETSC_ALIAS_FUNCTION_WITH_PROLOGUE_AND_EPILOGUE_(alias, original, prologue, epilogue) \
 85:   template <typename... Args> \
 86:   PETSC_NODISCARD auto alias(Args &&...args) PETSC_DECLTYPE_NOEXCEPT_AUTO(original(std::forward<Args>(args)...)) \
 87:   { \
 88:     prologue; \
 89:     auto ret = original(std::forward<Args>(args)...); \
 90:     epilogue; \
 91:     return ret; \
 92:   }

 94: // PETSC_ALIAS_FUNCTION() - Alias a function
 95: //
 96: // input params:
 97: // alias    - the new name for the function
 98: // original - the name of the function you would like to alias
 99: //
100: // notes:
101: // Using this macro in effect creates
102: //
103: // template 
104: // auto alias(T&&... args)
105: // {
106: //   return original(std::forward(args)...);
107: // }
108: //
109: // meaning it will transparently work for any kind of alias (including overloads).
110: //
111: // example usage:
112: // PETSC_ALIAS_FUNCTION(bar,foo);
113: #define PETSC_ALIAS_FUNCTION(alias, original) PETSC_ALIAS_FUNCTION_WITH_PROLOGUE_AND_EPILOGUE_(alias, original, ((void)0), ((void)0))

115: // Similar to PETSC_ALIAS_FUNCTION() this macro creates a thin wrapper which passes all
116: // arguments to the target function ~except~ the last N arguments. So
117: //
118: // PETSC_ALIAS_FUNCTION_GOBBLE_NTH_ARGS(bar,foo,3);
119: //
120: // creates a function with the effect of
121: //
122: // returnType bar(argType1 arg1, argType2 arg2, ..., argTypeN argN)
123: // {
124: //   IGNORE(argN);
125: //   IGNORE(argN-1);
126: //   IGNORE(argN-2);
127: //   return foo(arg1,arg2,...,argN-3);
128: // }
129: //
130: // for you.
131: #define PETSC_ALIAS_FUNCTION_GOBBLE_NTH_LAST_ARGS_(alias, original, gobblefn, N) \
132:   static_assert(std::is_integral<decltype(N)>::value && ((N) >= 0), ""); \
133:   template <typename TupleT, std::size_t... idx> \
134:   static inline auto gobblefn(TupleT &&tuple, Petsc::util::index_sequence<idx...>) PETSC_DECLTYPE_NOEXCEPT_AUTO_RETURNS(original(std::get<idx>(tuple)...)) \
135:   template <typename... Args> \
136:   PETSC_NODISCARD auto alias(Args &&...args) PETSC_DECLTYPE_NOEXCEPT_AUTO_RETURNS(gobblefn(std::forward_as_tuple(args...), Petsc::util::make_index_sequence<sizeof...(Args) - (N)>{}))

138: // makes prefix_lineno_name
139: #define PETSC_ALIAS_UNIQUE_NAME_INTERNAL_(a, b, c, d, e) a##b##c##d##e
140: #define PETSC_ALIAS_UNIQUE_NAME_INTERNAL(prefix, name)   PETSC_ALIAS_UNIQUE_NAME_INTERNAL_(prefix, _, __LINE__, _, name)

142: #define PETSC_ALIAS_FUNCTION_GOBBLE_NTH_LAST_ARGS(alias, original, N) PETSC_ALIAS_FUNCTION_GOBBLE_NTH_LAST_ARGS_(alias, original, PETSC_ALIAS_UNIQUE_NAME_INTERNAL(PetscAliasFunctionGobbleDispatch, original), N)