llvm-project/libcxx/include/__memory/pointer_traits.h
Christopher Di Bella 332da1c283 [libcxx][iwyu] ensures we IWYU as prep for modules
This has been broken out of D104170 since it should be merged whether or
not we go ahead with the module map changes.

Differential Revision: https://reviews.llvm.org/D104175
2021-06-15 19:43:25 +00:00

217 lines
6.6 KiB
C++

// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP___MEMORY_POINTER_TRAITS_H
#define _LIBCPP___MEMORY_POINTER_TRAITS_H
#include <__config>
#include <__memory/addressof.h>
#include <type_traits>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#pragma GCC system_header
#endif
_LIBCPP_PUSH_MACROS
#include <__undef_macros>
_LIBCPP_BEGIN_NAMESPACE_STD
template <class _Tp, class = void>
struct __has_element_type : false_type {};
template <class _Tp>
struct __has_element_type<_Tp,
typename __void_t<typename _Tp::element_type>::type> : true_type {};
template <class _Ptr, bool = __has_element_type<_Ptr>::value>
struct __pointer_traits_element_type;
template <class _Ptr>
struct __pointer_traits_element_type<_Ptr, true>
{
typedef _LIBCPP_NODEBUG_TYPE typename _Ptr::element_type type;
};
template <template <class, class...> class _Sp, class _Tp, class ..._Args>
struct __pointer_traits_element_type<_Sp<_Tp, _Args...>, true>
{
typedef _LIBCPP_NODEBUG_TYPE typename _Sp<_Tp, _Args...>::element_type type;
};
template <template <class, class...> class _Sp, class _Tp, class ..._Args>
struct __pointer_traits_element_type<_Sp<_Tp, _Args...>, false>
{
typedef _LIBCPP_NODEBUG_TYPE _Tp type;
};
template <class _Tp, class = void>
struct __has_difference_type : false_type {};
template <class _Tp>
struct __has_difference_type<_Tp,
typename __void_t<typename _Tp::difference_type>::type> : true_type {};
template <class _Ptr, bool = __has_difference_type<_Ptr>::value>
struct __pointer_traits_difference_type
{
typedef _LIBCPP_NODEBUG_TYPE ptrdiff_t type;
};
template <class _Ptr>
struct __pointer_traits_difference_type<_Ptr, true>
{
typedef _LIBCPP_NODEBUG_TYPE typename _Ptr::difference_type type;
};
template <class _Tp, class _Up>
struct __has_rebind
{
private:
struct __two {char __lx; char __lxx;};
template <class _Xp> static __two __test(...);
_LIBCPP_SUPPRESS_DEPRECATED_PUSH
template <class _Xp> static char __test(typename _Xp::template rebind<_Up>* = 0);
_LIBCPP_SUPPRESS_DEPRECATED_POP
public:
static const bool value = sizeof(__test<_Tp>(0)) == 1;
};
template <class _Tp, class _Up, bool = __has_rebind<_Tp, _Up>::value>
struct __pointer_traits_rebind
{
#ifndef _LIBCPP_CXX03_LANG
typedef _LIBCPP_NODEBUG_TYPE typename _Tp::template rebind<_Up> type;
#else
typedef _LIBCPP_NODEBUG_TYPE typename _Tp::template rebind<_Up>::other type;
#endif
};
template <template <class, class...> class _Sp, class _Tp, class ..._Args, class _Up>
struct __pointer_traits_rebind<_Sp<_Tp, _Args...>, _Up, true>
{
#ifndef _LIBCPP_CXX03_LANG
typedef _LIBCPP_NODEBUG_TYPE typename _Sp<_Tp, _Args...>::template rebind<_Up> type;
#else
typedef _LIBCPP_NODEBUG_TYPE typename _Sp<_Tp, _Args...>::template rebind<_Up>::other type;
#endif
};
template <template <class, class...> class _Sp, class _Tp, class ..._Args, class _Up>
struct __pointer_traits_rebind<_Sp<_Tp, _Args...>, _Up, false>
{
typedef _Sp<_Up, _Args...> type;
};
template <class _Ptr>
struct _LIBCPP_TEMPLATE_VIS pointer_traits
{
typedef _Ptr pointer;
typedef typename __pointer_traits_element_type<pointer>::type element_type;
typedef typename __pointer_traits_difference_type<pointer>::type difference_type;
#ifndef _LIBCPP_CXX03_LANG
template <class _Up> using rebind = typename __pointer_traits_rebind<pointer, _Up>::type;
#else
template <class _Up> struct rebind
{typedef typename __pointer_traits_rebind<pointer, _Up>::type other;};
#endif // _LIBCPP_CXX03_LANG
private:
struct __nat {};
public:
_LIBCPP_INLINE_VISIBILITY
static pointer pointer_to(typename conditional<is_void<element_type>::value,
__nat, element_type>::type& __r)
{return pointer::pointer_to(__r);}
};
template <class _Tp>
struct _LIBCPP_TEMPLATE_VIS pointer_traits<_Tp*>
{
typedef _Tp* pointer;
typedef _Tp element_type;
typedef ptrdiff_t difference_type;
#ifndef _LIBCPP_CXX03_LANG
template <class _Up> using rebind = _Up*;
#else
template <class _Up> struct rebind {typedef _Up* other;};
#endif
private:
struct __nat {};
public:
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
static pointer pointer_to(typename conditional<is_void<element_type>::value,
__nat, element_type>::type& __r) _NOEXCEPT
{return _VSTD::addressof(__r);}
};
template <class _From, class _To>
struct __rebind_pointer {
#ifndef _LIBCPP_CXX03_LANG
typedef typename pointer_traits<_From>::template rebind<_To> type;
#else
typedef typename pointer_traits<_From>::template rebind<_To>::other type;
#endif
};
// to_address
template <class _Pointer, class = void>
struct __to_address_helper;
template <class _Tp>
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
_Tp* __to_address(_Tp* __p) _NOEXCEPT {
static_assert(!is_function<_Tp>::value, "_Tp is a function type");
return __p;
}
// enable_if is needed here to avoid instantiating checks for fancy pointers on raw pointers
template <class _Pointer, class = _EnableIf<!is_pointer<_Pointer>::value> >
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
typename decay<decltype(__to_address_helper<_Pointer>::__call(declval<const _Pointer&>()))>::type
__to_address(const _Pointer& __p) _NOEXCEPT {
return __to_address_helper<_Pointer>::__call(__p);
}
template <class _Pointer, class>
struct __to_address_helper {
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
static decltype(_VSTD::__to_address(declval<const _Pointer&>().operator->()))
__call(const _Pointer&__p) _NOEXCEPT {
return _VSTD::__to_address(__p.operator->());
}
};
template <class _Pointer>
struct __to_address_helper<_Pointer, decltype((void)pointer_traits<_Pointer>::to_address(declval<const _Pointer&>()))> {
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
static decltype(pointer_traits<_Pointer>::to_address(declval<const _Pointer&>()))
__call(const _Pointer&__p) _NOEXCEPT {
return pointer_traits<_Pointer>::to_address(__p);
}
};
#if _LIBCPP_STD_VER > 17
template <class _Pointer>
inline _LIBCPP_INLINE_VISIBILITY constexpr
auto to_address(const _Pointer& __p) noexcept {
return _VSTD::__to_address(__p);
}
#endif
_LIBCPP_END_NAMESPACE_STD
_LIBCPP_POP_MACROS
#endif // _LIBCPP___MEMORY_POINTER_TRAITS_H