using __ptr_traits_elem_t = typename __ptr_traits_elem<_Ptr>::type;
/// @endcond
// Define pointer_traits::pointer_to.
template::value>
struct __ptr_traits_ptr_to
{
using pointer = _Ptr;
using element_type = _Elt;
/**
* @brief Obtain a pointer to an object
* @param __r A reference to an object of type `element_type`
* @return `pointer::pointer_to(__r)`
* @pre `pointer::pointer_to(__r)` is a valid expression.
*/
static pointer
pointer_to(element_type& __r)
#if __cpp_lib_concepts
requires requires {
{ pointer::pointer_to(__r) } -> convertible_to;
}
#endif
{ return pointer::pointer_to(__r); }
};
// Do not define pointer_traits::pointer_to if element type is void.
template
struct __ptr_traits_ptr_to<_Ptr, _Elt, true>
{ };
// Partial specialization defining pointer_traits::pointer_to(T&).
template
struct __ptr_traits_ptr_to<_Tp*, _Tp, false>
{
using pointer = _Tp*;
using element_type = _Tp;
/**
* @brief Obtain a pointer to an object
* @param __r A reference to an object of type `element_type`
* @return `addressof(__r)`
*/
static _GLIBCXX20_CONSTEXPR pointer
pointer_to(element_type& __r) noexcept
{ return std::addressof(__r); }
};
template
struct __ptr_traits_impl : __ptr_traits_ptr_to<_Ptr, _Elt>
{
private:
template
using __diff_t = typename _Tp::difference_type;
template
using __rebind = __type_identity>;
public:
/// The pointer type.
using pointer = _Ptr;
/// The type pointed to.
using element_type = _Elt;
/// The type used to represent the difference between two pointers.
using difference_type = __detected_or_t;
/// A pointer to a different type.
template
using rebind = typename __detected_or_t<__replace_first_arg<_Ptr, _Up>,
__rebind, _Ptr, _Up>::type;
};
// _GLIBCXX_RESOLVE_LIB_DEFECTS
// 3545. std::pointer_traits should be SFINAE-friendly
template
struct __ptr_traits_impl<_Ptr, __undefined>
{ };
/**
* @brief Uniform interface to all pointer-like types
* @headerfile memory
* @ingroup pointer_abstractions
* @since C++11
*/
template
struct pointer_traits : __ptr_traits_impl<_Ptr, __ptr_traits_elem_t<_Ptr>>
{ };
/**
* @brief Partial specialization for built-in pointers.
* @headerfile memory
* @ingroup pointer_abstractions
* @since C++11
*/
template
struct pointer_traits<_Tp*> : __ptr_traits_ptr_to<_Tp*, _Tp>
{
/// The pointer type
typedef _Tp* pointer;
/// The type pointed to
typedef _Tp element_type;
/// Type used to represent the difference between two pointers
typedef ptrdiff_t difference_type;
/// A pointer to a different type.
template using rebind = _Up*;
};
/// Convenience alias for rebinding pointers.
template
using __ptr_rebind = typename pointer_traits<_Ptr>::template rebind<_Tp>;
#ifndef __glibcxx_to_address // C++ < 20
template
[[__gnu__::__always_inline__]]
constexpr _Tp*
__to_address(_Tp* __ptr) noexcept
{
static_assert(!std::is_function<_Tp>::value, "std::to_address argument "
"must not be a function pointer");
return __ptr;
}
// This should only be used for pointer-like types (e.g. allocator pointers)
// and (in C++20 and later) for types satisfying std::contiguous_iterator.
// It should not be used for arbitrary random access iterators, because
// they might not be contiguous iterators (e.g. deque::iterator isn't).
template
constexpr typename std::pointer_traits<_Ptr>::element_type*
__to_address(const _Ptr& __ptr)
{ return std::__to_address(__ptr.operator->()); }
#else
/**
* @brief Obtain address referenced by a pointer to an object
* @param __ptr A pointer to an object
* @return `__ptr`
* @ingroup pointer_abstractions
*/
template
[[__gnu__::__always_inline__]]
constexpr _Tp*
to_address(_Tp* __ptr) noexcept
{
static_assert(!is_function_v<_Tp>, "std::to_address argument "
"must not be a function pointer");
return __ptr;
}
/**
* @brief Obtain address referenced by a pointer to an object
* @param __ptr A pointer to an object
* @return `pointer_traits<_Ptr>::to_address(__ptr)` if that expression is
* well-formed, otherwise `to_address(__ptr.operator->())`.
* @ingroup pointer_abstractions
*/
template
constexpr auto
to_address(const _Ptr& __ptr) noexcept
{
if constexpr (requires { pointer_traits<_Ptr>::to_address(__ptr); })
return pointer_traits<_Ptr>::to_address(__ptr);
else if constexpr (is_base_of_v<__gnu_debug::_Safe_iterator_base, _Ptr>)
return std::to_address(__ptr.base().operator->());
else
return std::to_address(__ptr.operator->());
}
/// @cond undocumented
/// Compatibility for use in code that is also compiled as pre-C++20.
template
[[__gnu__::__always_inline__]]
constexpr auto
__to_address(const _Ptr& __ptr) noexcept
{ return std::to_address(__ptr); }
/// @endcond
#endif // __glibcxx_to_address
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
#endif
#endif