blob: 8d46eae857648420edb31cffb1589a8d1c16f52e (
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
|
#ifndef MAPBOX_UTIL_OPTIONAL_HPP
#define MAPBOX_UTIL_OPTIONAL_HPP
#include <type_traits>
#include <mbgl/util/variant.hpp>
namespace mapbox
{
namespace util
{
template <typename T> class optional
{
static_assert(!std::is_reference<T>::value, "optional doesn't support references");
struct none_type
{
};
variant<none_type, T> variant_;
public:
optional() = default;
optional(optional const &rhs)
{
if (this != &rhs)
{ // protect against invalid self-assignment
variant_ = rhs.variant_;
}
}
optional(T const &v) { variant_ = v; }
explicit operator bool() const noexcept { return variant_.template is<T>(); }
T const &get() const { return variant_.template get<T>(); }
T &get() { return variant_.template get<T>(); }
T const &operator*() const { return this->get(); }
T operator*() { return this->get(); }
optional &operator=(T const &v)
{
variant_ = v;
return *this;
}
optional &operator=(optional const &rhs)
{
if (this != &rhs)
{
variant_ = rhs.variant_;
}
return *this;
}
template <typename... Args> void emplace(Args &&... args)
{
variant_ = T{std::forward<Args>(args)...};
}
void reset() { variant_ = none_type{}; }
};
}
}
#endif
|
