158 lines
4 KiB
C++
158 lines
4 KiB
C++
#ifndef _OS_CPP_UTIL_H
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#define _OS_CPP_UTIL_H
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#include <sys/cdefs.h>
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#include <sys/_types/_size_t.h>
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#if __has_feature(cxx_nullptr) && __has_feature(cxx_decltype)
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# define OS_HAS_NULLPTR 1
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#endif
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#if __has_feature(cxx_rvalue_references) || __has_extension(cxx_rvalue_references)
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# define OS_HAS_RVALUE_REFERENCES 1
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#endif
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#if (defined(__has_include) && __has_include(<__xnu_libcxx_sentinel.h>) && __has_include(<new>))
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#include <new>
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#else
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void* operator new(size_t, void*) noexcept; // forward declaration needed for placement-new
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#endif
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namespace os {
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#if OS_HAS_NULLPTR
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typedef decltype(nullptr) nullptr_t;
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#endif
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/*
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* Reference removal
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*/
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template <class _T> struct remove_reference {typedef _T type;};
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template <class _T> struct remove_reference<_T&> {typedef _T type;};
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template <class _T> struct remove_reference<_T &&> {typedef _T type;};
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template <class _T> using remove_reference_t = typename remove_reference<_T>::type;
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/*
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* Pointer removal
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*/
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template <class _T> struct remove_pointer {typedef _T type;};
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template <class _T> struct remove_pointer<_T*> {typedef _T type;};
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template <class _T> struct remove_pointer<_T* const> {typedef _T type;};
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template <class _T> struct remove_pointer<_T* volatile> {typedef _T type;};
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template <class _T> struct remove_pointer<_T* const volatile> {typedef _T type;};
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template <class _T> using remove_pointer_t = typename remove_pointer<_T>::type;
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/*
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* Const removal
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*/
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template <class _T> struct remove_const {typedef _T type;};
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template <class _T> struct remove_const<const _T> {typedef _T type;};
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template <class _T> using remove_const_t = typename remove_const<_T>::type;
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/*
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* Volatile removal
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*/
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template <class _T> struct remove_volatile {typedef _T type;};
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template <class _T> struct remove_volatile<volatile _T> {typedef _T type;};
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template <class _T> using remove_volatile_t = typename remove_volatile<_T>::type;
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/*
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* Extent removal
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*/
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template<class _T> struct remove_extent { typedef _T type; };
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template<class _T> struct remove_extent<_T[]> { typedef _T type; };
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template<class _T, size_t N> struct remove_extent<_T[N]> { typedef _T type; };
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template <class _T> using remove_extent_t = typename remove_extent<_T>::type;
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template <class T> struct is_lvalue_reference { static constexpr bool value = false; };
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template <class T> struct is_lvalue_reference<T&> { static constexpr bool value = true; };
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/*
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* is_same
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*/
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template<class T, class U> struct is_same { static constexpr bool value = false; };
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template<class T> struct is_same<T, T> { static constexpr bool value = true; };
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/*
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* Move
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*/
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template <class _T>
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inline typename remove_reference<_T>::type &&
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move(_T && _t)
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{
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typedef typename os::remove_reference<_T>::type _U;
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return static_cast<_U &&>(_t);
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}
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template <class T>
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T*
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move(T* first, T* last, T* d_first)
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{
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for (; first != last; ++d_first, (void)++first) {
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*d_first = os::move(*first);
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}
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return d_first;
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}
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template <class T>
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constexpr T && forward(os::remove_reference_t<T>&t) noexcept {
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return static_cast<T &&>(t);
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}
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template <class T>
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constexpr T && forward(os::remove_reference_t<T>&& t) noexcept {
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static_assert(!os::is_lvalue_reference<T>::value,
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"can not forward an rvalue as an lvalue");
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return static_cast<T &&>(t);
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}
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// Moves [first, last) into the range ending at d_last,
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// proceeding backwards (from last to first)
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// UB if d_last is within (first, last]
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template <class T>
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T*
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move_backward(T* first, T* last, T* d_last)
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{
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while (first != last) {
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*(--d_last) = os::move(*(--last));
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}
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return d_last;
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}
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template <class T>
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T*
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uninitialized_move(T* first, T* last, T* d_first)
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{
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for (; first != last; ++d_first, (void) ++first) {
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::new (static_cast<void*>(d_first)) T(os::move(*first));
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}
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return first;
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}
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template <class T>
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void
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destroy(T* first, T* last)
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{
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for (; first != last; ++first) {
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first->~T();
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}
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}
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template <class T>
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void
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uninitialized_value_construct(T* first, T* last)
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{
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for (; first != last; ++first) {
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::new (static_cast<void*>(first)) T();
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}
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}
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}
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#endif /* _OS_CPP_UTIL_H */
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