1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
|
/* 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
|
