-
Notifications
You must be signed in to change notification settings - Fork 50
/
Arity.h
58 lines (51 loc) · 1.95 KB
/
Arity.h
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
/*
* Copyright (c) Meta Platforms, Inc. and affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*/
#pragma once
#include <type_traits>
namespace sparta {
// Template helpers to get the array of a function type or similar.
template <typename T, bool IS_FUNC>
struct GetArity;
template <typename T>
struct GetArity<T, true> {
template <typename R>
struct get_arity;
template <typename R, typename... Args>
struct get_arity<R(Args...)>
: std::integral_constant<unsigned, sizeof...(Args)> {};
template <typename R, typename... Args>
struct get_arity<R (*)(Args...)>
: std::integral_constant<unsigned, sizeof...(Args)> {};
template <typename R, typename C, typename... Args>
struct get_arity<R (C::*)(Args...)>
: std::integral_constant<unsigned, sizeof...(Args)> {};
template <typename R, typename C, typename... Args>
struct get_arity<R (C::*)(Args...) const>
: std::integral_constant<unsigned, sizeof...(Args)> {};
static constexpr unsigned value = get_arity<T>::value;
};
template <typename T>
struct GetArity<T, false> {
template <typename R>
struct get_arity : get_arity<decltype(&R::operator())> {};
template <typename R, typename... Args>
struct get_arity<R(Args...)>
: std::integral_constant<unsigned, sizeof...(Args)> {};
template <typename R, typename... Args>
struct get_arity<R (*)(Args...)>
: std::integral_constant<unsigned, sizeof...(Args)> {};
template <typename R, typename C, typename... Args>
struct get_arity<R (C::*)(Args...)>
: std::integral_constant<unsigned, sizeof...(Args)> {};
template <typename R, typename C, typename... Args>
struct get_arity<R (C::*)(Args...) const>
: std::integral_constant<unsigned, sizeof...(Args)> {};
static constexpr unsigned value = get_arity<T>::value;
};
template <typename T>
struct Arity : GetArity<T, std::is_function<T>::value> {};
} // namespace sparta