#ifndef _OS_CPP_UTIL_H
#define _OS_CPP_UTIL_H
#include <sys/cdefs.h>
#if __has_feature(cxx_nullptr) && __has_feature(cxx_decltype)
# define OS_HAS_NULLPTR 1
#endif
#if __has_feature(cxx_rvalue_references) || __has_extension(cxx_rvalue_references)
# define OS_HAS_RVALUE_REFERENCES 1
#endif
void* operator new(size_t, void*);
namespace os {
#if OS_HAS_NULLPTR
typedef decltype(nullptr) nullptr_t;
#endif
template <class _T> struct remove_reference {typedef _T type;};
template <class _T> struct remove_reference<_T&> {typedef _T type;};
template <class _T> struct remove_reference<_T &&> {typedef _T type;};
template <class _T> using remove_reference_t = typename remove_reference<_T>::type;
template <class _T> struct remove_const {typedef _T type;};
template <class _T> struct remove_const<const _T> {typedef _T type;};
template <class _T> using remove_const_t = typename remove_const<_T>::type;
template <class T> struct is_lvalue_reference { static constexpr bool value = false; };
template <class T> struct is_lvalue_reference<T&> { static constexpr bool value = true; };
template <class _T>
inline typename remove_reference<_T>::type &&
move(_T && _t)
{
typedef typename os::remove_reference<_T>::type _U;
return static_cast<_U &&>(_t);
}
template <class T>
T*
move(T* first, T* last, T* d_first)
{
for (; first != last; ++d_first, (void)++first) {
*d_first = os::move(*first);
}
return d_first;
}
template <class T>
constexpr T && forward(os::remove_reference_t<T>&t) noexcept {
return static_cast<T &&>(t);
}
template <class T>
constexpr T && forward(os::remove_reference_t<T>&& t) noexcept {
static_assert(!os::is_lvalue_reference<T>::value,
"can not forward an rvalue as an lvalue");
return static_cast<T &&>(t);
}
template <class T>
T*
move_backward(T* first, T* last, T* d_last)
{
while (first != last) {
*(--d_last) = os::move(*(--last));
}
return d_last;
}
template <class T>
T*
uninitialized_move(T* first, T* last, T* d_first)
{
for (; first != last; ++d_first, (void) ++first) {
::new (static_cast<void*>(d_first)) T(os::move(*first));
}
return first;
}
template <class T>
void
destroy(T* first, T* last)
{
for (; first != last; ++first) {
first->~T();
}
}
template <class T>
void
uninitialized_value_construct(T* first, T* last)
{
for (; first != last; ++first) {
::new (static_cast<void*>(first)) T();
}
}
}
#endif