Green Sky
227425b90e
git-subtree-dir: external/toxcore/c-toxcore git-subtree-split: 67badf69416a74e74f6d7eb51dd96f37282b8455
70 lines
1.9 KiB
C++
70 lines
1.9 KiB
C++
/* SPDX-License-Identifier: GPL-3.0-or-later
|
|
* Copyright © 2022 The TokTok team.
|
|
*/
|
|
|
|
#ifndef C_TOXCORE_TESTING_FUZZING_FUNC_CONVERSION_H
|
|
#define C_TOXCORE_TESTING_FUZZING_FUNC_CONVERSION_H
|
|
|
|
namespace detail {
|
|
|
|
template <typename F, F f>
|
|
struct func_conversion {
|
|
private:
|
|
template <typename R, typename... Args>
|
|
using func_pointer = R (*)(Args...);
|
|
|
|
template <typename From>
|
|
struct static_caster {
|
|
From obj;
|
|
|
|
template <typename To>
|
|
operator To() const
|
|
{
|
|
return static_cast<To>(obj);
|
|
}
|
|
};
|
|
|
|
public:
|
|
template <typename R, typename Arg, typename... Args>
|
|
constexpr operator func_pointer<R, Arg, Args...>()
|
|
{
|
|
return [](Arg obj, auto... args) { return f(static_caster<Arg>{obj}, args...); };
|
|
}
|
|
};
|
|
|
|
template <typename F>
|
|
struct make_funptr;
|
|
|
|
template <typename T, typename R, typename... Args>
|
|
struct make_funptr<R (T::*)(Args...) const> {
|
|
using type = R (*)(Args...);
|
|
};
|
|
|
|
/** @brief Turn a memfunptr type into a plain funptr type.
|
|
*
|
|
* Not needed in C++20, because we can pass the lambda itself as template
|
|
* argument, but in C++17, we need to do an early conversion.
|
|
*/
|
|
template <typename F>
|
|
using make_funptr_t = typename make_funptr<F>::type;
|
|
|
|
}
|
|
|
|
/** @brief Turn a C++ lambda into a C function pointer with `void*` param.
|
|
*
|
|
* Takes a lambda function with any pointer type as first parameter and turns it
|
|
* into a C function pointer with `void*` as the first parameter. Internally, it
|
|
* `static_cast`s that `void*` to the lambda's parameter type, avoiding a bunch
|
|
* of casts inside the lambdas.
|
|
*
|
|
* This works on any type `T` that can be `static_cast` to `U`, not just `void*`
|
|
* to `U*`, but the common case for C callbacks is `void*`.
|
|
*/
|
|
template <typename F>
|
|
static constexpr auto operator!(F f)
|
|
{
|
|
return detail::func_conversion<detail::make_funptr_t<decltype(&F::operator())>, f>{};
|
|
}
|
|
|
|
#endif // C_TOXCORE_TESTING_FUZZING_FUNC_CONVERSION_H
|