1 | #ifndef _OS_CPP_UTIL_H |
2 | #define _OS_CPP_UTIL_H |
3 | |
4 | #include <sys/cdefs.h> |
5 | #include <sys/_types/_size_t.h> |
6 | |
7 | #if __has_feature(cxx_nullptr) && __has_feature(cxx_decltype) |
8 | # define OS_HAS_NULLPTR 1 |
9 | #endif |
10 | |
11 | #if __has_feature(cxx_rvalue_references) || __has_extension(cxx_rvalue_references) |
12 | # define OS_HAS_RVALUE_REFERENCES 1 |
13 | #endif |
14 | |
15 | #if (defined(__has_include) && __has_include(<__xnu_libcxx_sentinel.h>) && __has_include(<new>)) |
16 | #include <new> |
17 | #else |
18 | void* operator new(size_t, void*) noexcept; // forward declaration needed for placement-new |
19 | #endif |
20 | |
21 | namespace os { |
22 | #if OS_HAS_NULLPTR |
23 | typedef decltype(nullptr) nullptr_t; |
24 | #endif |
25 | |
26 | /* |
27 | * Reference removal |
28 | */ |
29 | |
30 | template <class _T> struct remove_reference {typedef _T type;}; |
31 | template <class _T> struct remove_reference<_T&> {typedef _T type;}; |
32 | template <class _T> struct remove_reference<_T &&> {typedef _T type;}; |
33 | template <class _T> using remove_reference_t = typename remove_reference<_T>::type; |
34 | |
35 | /* |
36 | * Pointer removal |
37 | */ |
38 | |
39 | template <class _T> struct remove_pointer {typedef _T type;}; |
40 | template <class _T> struct remove_pointer<_T*> {typedef _T type;}; |
41 | template <class _T> struct remove_pointer<_T* const> {typedef _T type;}; |
42 | template <class _T> struct remove_pointer<_T* volatile> {typedef _T type;}; |
43 | template <class _T> struct remove_pointer<_T* const volatile> {typedef _T type;}; |
44 | template <class _T> using remove_pointer_t = typename remove_pointer<_T>::type; |
45 | |
46 | /* |
47 | * Const removal |
48 | */ |
49 | |
50 | template <class _T> struct remove_const {typedef _T type;}; |
51 | template <class _T> struct remove_const<const _T> {typedef _T type;}; |
52 | template <class _T> using remove_const_t = typename remove_const<_T>::type; |
53 | |
54 | /* |
55 | * Volatile removal |
56 | */ |
57 | |
58 | template <class _T> struct remove_volatile {typedef _T type;}; |
59 | template <class _T> struct remove_volatile<volatile _T> {typedef _T type;}; |
60 | template <class _T> using remove_volatile_t = typename remove_volatile<_T>::type; |
61 | |
62 | /* |
63 | * Extent removal |
64 | */ |
65 | |
66 | template<class _T> struct remove_extent { typedef _T type; }; |
67 | template<class _T> struct remove_extent<_T[]> { typedef _T type; }; |
68 | template<class _T, size_t N> struct remove_extent<_T[N]> { typedef _T type; }; |
69 | template <class _T> using remove_extent_t = typename remove_extent<_T>::type; |
70 | |
71 | |
72 | template <class T> struct is_lvalue_reference { static constexpr bool value = false; }; |
73 | template <class T> struct is_lvalue_reference<T&> { static constexpr bool value = true; }; |
74 | |
75 | /* |
76 | * is_same |
77 | */ |
78 | |
79 | template<class T, class U> struct is_same { static constexpr bool value = false; }; |
80 | template<class T> struct is_same<T, T> { static constexpr bool value = true; }; |
81 | |
82 | /* |
83 | * Move |
84 | */ |
85 | |
86 | template <class _T> |
87 | inline typename remove_reference<_T>::type && |
88 | move(_T && _t) |
89 | { |
90 | typedef typename os::remove_reference<_T>::type _U; |
91 | return static_cast<_U &&>(_t); |
92 | } |
93 | |
94 | template <class T> |
95 | T* |
96 | move(T* first, T* last, T* d_first) |
97 | { |
98 | for (; first != last; ++d_first, (void)++first) { |
99 | *d_first = os::move(*first); |
100 | } |
101 | return d_first; |
102 | } |
103 | |
104 | template <class T> |
105 | constexpr T && forward(os::remove_reference_t<T>&t) noexcept { |
106 | return static_cast<T &&>(t); |
107 | } |
108 | |
109 | template <class T> |
110 | constexpr T && forward(os::remove_reference_t<T>&& t) noexcept { |
111 | static_assert(!os::is_lvalue_reference<T>::value, |
112 | "can not forward an rvalue as an lvalue" ); |
113 | return static_cast<T &&>(t); |
114 | } |
115 | |
116 | // Moves [first, last) into the range ending at d_last, |
117 | // proceeding backwards (from last to first) |
118 | // UB if d_last is within (first, last] |
119 | template <class T> |
120 | T* |
121 | move_backward(T* first, T* last, T* d_last) |
122 | { |
123 | while (first != last) { |
124 | *(--d_last) = os::move(*(--last)); |
125 | } |
126 | return d_last; |
127 | } |
128 | |
129 | template <class T> |
130 | T* |
131 | uninitialized_move(T* first, T* last, T* d_first) |
132 | { |
133 | for (; first != last; ++d_first, (void) ++first) { |
134 | ::new (static_cast<void*>(d_first)) T(os::move(*first)); |
135 | } |
136 | return first; |
137 | } |
138 | |
139 | template <class T> |
140 | void |
141 | destroy(T* first, T* last) |
142 | { |
143 | for (; first != last; ++first) { |
144 | first->~T(); |
145 | } |
146 | } |
147 | |
148 | template <class T> |
149 | void |
150 | uninitialized_value_construct(T* first, T* last) |
151 | { |
152 | for (; first != last; ++first) { |
153 | ::new (static_cast<void*>(first)) T(); |
154 | } |
155 | } |
156 | } |
157 | |
158 | #endif /* _OS_CPP_UTIL_H */ |
159 | |