blob: c4d013a69ee984e0c83440ab8c4aff7b2190f1bf (
plain)
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
70
71
72
73
74
|
/* Copyright (C) 2016 Murray Cumming
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/
*/
#ifndef SIGC_TUPLE_UTILS_TUPLE_CDR_H
#define SIGC_TUPLE_UTILS_TUPLE_CDR_H
#include <tuple>
#include <type_traits>
#include <utility>
namespace sigc {
namespace internal {
/**
* Get the type of a tuple without the first item.
*/
template <typename T>
struct tuple_type_cdr; // primary template is not defined
// Partial specialization for tuples of at least one element:
template <typename H, typename... T>
struct tuple_type_cdr<std::tuple<H, T...>>
{
using type = std::tuple<T...>;
};
namespace detail {
template <typename T, std::size_t... I>
constexpr
decltype(auto)
tuple_cdr_impl(T&& t, std::index_sequence<0, I...>)
{
using cdr = typename tuple_type_cdr<std::decay_t<T>>::type;
return cdr(std::get<I>(std::forward<T>(t))...);
}
} // detail namespace
/**
* Get the a tuple without the first item.
* This is analogous to std::tuple_cat().
*/
template <typename T>
constexpr
decltype(auto)
tuple_cdr(T&& t) {
//We use std::decay_t<> because tuple_size is not defined for references.
constexpr auto size = std::tuple_size<std::decay_t<T>>::value;
static_assert(size != 0, "tuple size must be non-zero");
using seq = std::make_index_sequence<size>;
return detail::tuple_cdr_impl(std::forward<T>(t), seq{});
}
} // namespace internal
} // namespace sigc
#endif //SIGC_TUPLE_UTILS_TUPLE_CDR_H
|
