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// -*- 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_ALLOCATOR_H
#define _LIBCPP___MEMORY_ALLOCATOR_H
#include <__config>
#include <__cstddef/ptrdiff_t.h>
#include <__cstddef/size_t.h>
#include <__memory/addressof.h>
#include <__memory/allocate_at_least.h>
#include <__memory/allocator_traits.h>
#include <__new/allocate.h>
#include <__new/exceptions.h>
#include <__type_traits/is_const.h>
#include <__type_traits/is_constant_evaluated.h>
#include <__type_traits/is_same.h>
#include <__type_traits/is_void.h>
#include <__type_traits/is_volatile.h>
#include <__utility/forward.h>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
template <class _Tp>
class allocator;
#if _LIBCPP_STD_VER <= 17
// These specializations shouldn't be marked _LIBCPP_DEPRECATED_IN_CXX17.
// Specializing allocator<void> is deprecated, but not using it.
template <>
class _LIBCPP_TEMPLATE_VIS allocator<void> {
public:
_LIBCPP_DEPRECATED_IN_CXX17 typedef void* pointer;
_LIBCPP_DEPRECATED_IN_CXX17 typedef const void* const_pointer;
_LIBCPP_DEPRECATED_IN_CXX17 typedef void value_type;
template <class _Up>
struct _LIBCPP_DEPRECATED_IN_CXX17 rebind {
typedef allocator<_Up> other;
};
};
#endif // _LIBCPP_STD_VER <= 17
// This class provides a non-trivial default constructor to the class that derives from it
// if the condition is satisfied.
//
// The second template parameter exists to allow giving a unique type to __non_trivial_if,
// which makes it possible to avoid breaking the ABI when making this a base class of an
// existing class. Without that, imagine we have classes D1 and D2, both of which used to
// have no base classes, but which now derive from __non_trivial_if. The layout of a class
// that inherits from both D1 and D2 will change because the two __non_trivial_if base
// classes are not allowed to share the same address.
//
// By making those __non_trivial_if base classes unique, we work around this problem and
// it is safe to start deriving from __non_trivial_if in existing classes.
template <bool _Cond, class _Unique>
struct __non_trivial_if {};
template <class _Unique>
struct __non_trivial_if<true, _Unique> {
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR __non_trivial_if() _NOEXCEPT {}
};
// allocator
//
// Note: For ABI compatibility between C++20 and previous standards, we make
// allocator<void> trivial in C++20.
template <class _Tp>
class _LIBCPP_TEMPLATE_VIS allocator : private __non_trivial_if<!is_void<_Tp>::value, allocator<_Tp> > {
static_assert(!is_const<_Tp>::value, "std::allocator does not support const types");
static_assert(!is_volatile<_Tp>::value, "std::allocator does not support volatile types");
public:
typedef size_t size_type;
typedef ptrdiff_t difference_type;
typedef _Tp value_type;
typedef true_type propagate_on_container_move_assignment;
#if _LIBCPP_STD_VER <= 23 || defined(_LIBCPP_ENABLE_CXX26_REMOVED_ALLOCATOR_MEMBERS)
_LIBCPP_DEPRECATED_IN_CXX23 typedef true_type is_always_equal;
#endif
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 allocator() _NOEXCEPT = default;
template <class _Up>
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 allocator(const allocator<_Up>&) _NOEXCEPT {}
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Tp* allocate(size_t __n) {
static_assert(sizeof(_Tp) >= 0, "cannot allocate memory for an incomplete type");
if (__n > allocator_traits<allocator>::max_size(*this))
__throw_bad_array_new_length();
if (__libcpp_is_constant_evaluated()) {
return static_cast<_Tp*>(::operator new(__n * sizeof(_Tp)));
} else {
return std::__libcpp_allocate<_Tp>(__element_count(__n));
}
}
#if _LIBCPP_STD_VER >= 23
[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr allocation_result<_Tp*> allocate_at_least(size_t __n) {
static_assert(sizeof(_Tp) >= 0, "cannot allocate memory for an incomplete type");
return {allocate(__n), __n};
}
#endif
_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 void deallocate(_Tp* __p, size_t __n) _NOEXCEPT {
if (__libcpp_is_constant_evaluated()) {
::operator delete(__p);
} else {
std::__libcpp_deallocate<_Tp>(__p, __element_count(__n));
}
}
// C++20 Removed members
#if _LIBCPP_STD_VER <= 17
_LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp* pointer;
_LIBCPP_DEPRECATED_IN_CXX17 typedef const _Tp* const_pointer;
_LIBCPP_DEPRECATED_IN_CXX17 typedef _Tp& reference;
_LIBCPP_DEPRECATED_IN_CXX17 typedef const _Tp& const_reference;
template <class _Up>
struct _LIBCPP_DEPRECATED_IN_CXX17 rebind {
typedef allocator<_Up> other;
};
_LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_HIDE_FROM_ABI pointer address(reference __x) const _NOEXCEPT {
return std::addressof(__x);
}
_LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_HIDE_FROM_ABI const_pointer address(const_reference __x) const _NOEXCEPT {
return std::addressof(__x);
}
[[__nodiscard__]] _LIBCPP_HIDE_FROM_ABI _LIBCPP_DEPRECATED_IN_CXX17 _Tp* allocate(size_t __n, const void*) {
return allocate(__n);
}
_LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_HIDE_FROM_ABI size_type max_size() const _NOEXCEPT {
return size_type(~0) / sizeof(_Tp);
}
template <class _Up, class... _Args>
_LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_HIDE_FROM_ABI void construct(_Up* __p, _Args&&... __args) {
::new ((void*)__p) _Up(std::forward<_Args>(__args)...);
}
_LIBCPP_DEPRECATED_IN_CXX17 _LIBCPP_HIDE_FROM_ABI void destroy(pointer __p) { __p->~_Tp(); }
#endif
};
template <class _Tp, class _Up>
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 bool
operator==(const allocator<_Tp>&, const allocator<_Up>&) _NOEXCEPT {
return true;
}
#if _LIBCPP_STD_VER <= 17
template <class _Tp, class _Up>
inline _LIBCPP_HIDE_FROM_ABI bool operator!=(const allocator<_Tp>&, const allocator<_Up>&) _NOEXCEPT {
return false;
}
#endif
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___MEMORY_ALLOCATOR_H
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