// Allocator traits -*- C++ -*-
-// Copyright (C) 2011-2013 Free Software Foundation, Inc.
+// Copyright (C) 2011-2024 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
#ifndef _ALLOC_TRAITS_H
#define _ALLOC_TRAITS_H 1
+#include <bits/stl_construct.h>
+#include <bits/memoryfwd.h>
#if __cplusplus >= 201103L
-
-#include <bits/ptr_traits.h>
-#include <ext/numeric_traits.h>
+# include <bits/ptr_traits.h>
+# include <ext/numeric_traits.h>
+# if _GLIBCXX_HOSTED
+# include <bits/allocator.h>
+# endif
+#endif
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
- template<typename _Tp>
- class allocator;
-
- template<typename _Alloc, typename _Tp>
- class __alloctr_rebind_helper
- {
- template<typename _Alloc2, typename _Tp2>
- static constexpr bool
- _S_chk(typename _Alloc2::template rebind<_Tp2>::other*)
- { return true; }
-
- template<typename, typename>
- static constexpr bool
- _S_chk(...)
- { return false; }
-
- public:
- static const bool __value = _S_chk<_Alloc, _Tp>(nullptr);
- };
-
- template<typename _Alloc, typename _Tp>
- const bool __alloctr_rebind_helper<_Alloc, _Tp>::__value;
-
- template<typename _Alloc, typename _Tp,
- bool = __alloctr_rebind_helper<_Alloc, _Tp>::__value>
- struct __alloctr_rebind;
-
- template<typename _Alloc, typename _Tp>
- struct __alloctr_rebind<_Alloc, _Tp, true>
- {
- typedef typename _Alloc::template rebind<_Tp>::other __type;
- };
-
- template<template<typename, typename...> class _Alloc, typename _Tp,
- typename _Up, typename... _Args>
- struct __alloctr_rebind<_Alloc<_Up, _Args...>, _Tp, false>
- {
- typedef _Alloc<_Tp, _Args...> __type;
- };
+#if __cplusplus >= 201103L
+ /// @cond undocumented
+ struct __allocator_traits_base
+ {
+ template<typename _Tp, typename _Up, typename = void>
+ struct __rebind : __replace_first_arg<_Tp, _Up>
+ {
+ static_assert(is_same<
+ typename __replace_first_arg<_Tp, typename _Tp::value_type>::type,
+ _Tp>::value,
+ "allocator_traits<A>::rebind_alloc<A::value_type> must be A");
+ };
+
+ template<typename _Tp, typename _Up>
+ struct __rebind<_Tp, _Up,
+ __void_t<typename _Tp::template rebind<_Up>::other>>
+ {
+ using type = typename _Tp::template rebind<_Up>::other;
+
+ static_assert(is_same<
+ typename _Tp::template rebind<typename _Tp::value_type>::other,
+ _Tp>::value,
+ "allocator_traits<A>::rebind_alloc<A::value_type> must be A");
+ };
+
+ protected:
+ template<typename _Tp>
+ using __pointer = typename _Tp::pointer;
+ template<typename _Tp>
+ using __c_pointer = typename _Tp::const_pointer;
+ template<typename _Tp>
+ using __v_pointer = typename _Tp::void_pointer;
+ template<typename _Tp>
+ using __cv_pointer = typename _Tp::const_void_pointer;
+ template<typename _Tp>
+ using __pocca = typename _Tp::propagate_on_container_copy_assignment;
+ template<typename _Tp>
+ using __pocma = typename _Tp::propagate_on_container_move_assignment;
+ template<typename _Tp>
+ using __pocs = typename _Tp::propagate_on_container_swap;
+ template<typename _Tp>
+ using __equal = __type_identity<typename _Tp::is_always_equal>;
+ };
+
+ template<typename _Alloc, typename _Up>
+ using __alloc_rebind
+ = typename __allocator_traits_base::template __rebind<_Alloc, _Up>::type;
+ /// @endcond
/**
* @brief Uniform interface to all allocator types.
+ * @headerfile memory
* @ingroup allocators
+ * @since C++11
*/
template<typename _Alloc>
- struct allocator_traits
+ struct allocator_traits : __allocator_traits_base
{
/// The allocator type
typedef _Alloc allocator_type;
/// The allocated type
typedef typename _Alloc::value_type value_type;
-#define _GLIBCXX_ALLOC_TR_NESTED_TYPE(_NTYPE, _ALT) \
- private: \
- template<typename _Tp> \
- static typename _Tp::_NTYPE _S_##_NTYPE##_helper(_Tp*); \
- static _ALT _S_##_NTYPE##_helper(...); \
- typedef decltype(_S_##_NTYPE##_helper((_Alloc*)0)) __##_NTYPE; \
- public:
-
-_GLIBCXX_ALLOC_TR_NESTED_TYPE(pointer, value_type*)
-
/**
* @brief The allocator's pointer type.
*
* @c Alloc::pointer if that type exists, otherwise @c value_type*
*/
- typedef __pointer pointer;
+ using pointer = __detected_or_t<value_type*, __pointer, _Alloc>;
-_GLIBCXX_ALLOC_TR_NESTED_TYPE(const_pointer,
- typename pointer_traits<pointer>::template rebind<const value_type>)
+ private:
+ // Select _Func<_Alloc> or pointer_traits<pointer>::rebind<_Tp>
+ template<template<typename> class _Func, typename _Tp, typename = void>
+ struct _Ptr
+ {
+ using type = typename pointer_traits<pointer>::template rebind<_Tp>;
+ };
+ template<template<typename> class _Func, typename _Tp>
+ struct _Ptr<_Func, _Tp, __void_t<_Func<_Alloc>>>
+ {
+ using type = _Func<_Alloc>;
+ };
+
+ // Select _A2::difference_type or pointer_traits<_Ptr>::difference_type
+ template<typename _A2, typename _PtrT, typename = void>
+ struct _Diff
+ { using type = typename pointer_traits<_PtrT>::difference_type; };
+
+ template<typename _A2, typename _PtrT>
+ struct _Diff<_A2, _PtrT, __void_t<typename _A2::difference_type>>
+ { using type = typename _A2::difference_type; };
+
+ // Select _A2::size_type or make_unsigned<_DiffT>::type
+ template<typename _A2, typename _DiffT, typename = void>
+ struct _Size : make_unsigned<_DiffT> { };
+
+ template<typename _A2, typename _DiffT>
+ struct _Size<_A2, _DiffT, __void_t<typename _A2::size_type>>
+ { using type = typename _A2::size_type; };
+
+ public:
/**
* @brief The allocator's const pointer type.
*
* @c Alloc::const_pointer if that type exists, otherwise
* <tt> pointer_traits<pointer>::rebind<const value_type> </tt>
*/
- typedef __const_pointer const_pointer;
-
-_GLIBCXX_ALLOC_TR_NESTED_TYPE(void_pointer,
- typename pointer_traits<pointer>::template rebind<void>)
+ using const_pointer = typename _Ptr<__c_pointer, const value_type>::type;
/**
* @brief The allocator's void pointer type.
* @c Alloc::void_pointer if that type exists, otherwise
* <tt> pointer_traits<pointer>::rebind<void> </tt>
*/
- typedef __void_pointer void_pointer;
-
-_GLIBCXX_ALLOC_TR_NESTED_TYPE(const_void_pointer,
- typename pointer_traits<pointer>::template rebind<const void>)
+ using void_pointer = typename _Ptr<__v_pointer, void>::type;
/**
* @brief The allocator's const void pointer type.
* @c Alloc::const_void_pointer if that type exists, otherwise
* <tt> pointer_traits<pointer>::rebind<const void> </tt>
*/
- typedef __const_void_pointer const_void_pointer;
-
-_GLIBCXX_ALLOC_TR_NESTED_TYPE(difference_type,
- typename pointer_traits<pointer>::difference_type)
+ using const_void_pointer = typename _Ptr<__cv_pointer, const void>::type;
/**
* @brief The allocator's difference type
* @c Alloc::difference_type if that type exists, otherwise
* <tt> pointer_traits<pointer>::difference_type </tt>
*/
- typedef __difference_type difference_type;
-
-_GLIBCXX_ALLOC_TR_NESTED_TYPE(size_type,
- typename make_unsigned<difference_type>::type)
+ using difference_type = typename _Diff<_Alloc, pointer>::type;
/**
* @brief The allocator's size type
* @c Alloc::size_type if that type exists, otherwise
* <tt> make_unsigned<difference_type>::type </tt>
*/
- typedef __size_type size_type;
-
-_GLIBCXX_ALLOC_TR_NESTED_TYPE(propagate_on_container_copy_assignment,
- false_type)
+ using size_type = typename _Size<_Alloc, difference_type>::type;
/**
* @brief How the allocator is propagated on copy assignment
* @c Alloc::propagate_on_container_copy_assignment if that type exists,
* otherwise @c false_type
*/
- typedef __propagate_on_container_copy_assignment
- propagate_on_container_copy_assignment;
-
-_GLIBCXX_ALLOC_TR_NESTED_TYPE(propagate_on_container_move_assignment,
- false_type)
+ using propagate_on_container_copy_assignment
+ = __detected_or_t<false_type, __pocca, _Alloc>;
/**
* @brief How the allocator is propagated on move assignment
* @c Alloc::propagate_on_container_move_assignment if that type exists,
* otherwise @c false_type
*/
- typedef __propagate_on_container_move_assignment
- propagate_on_container_move_assignment;
-
-_GLIBCXX_ALLOC_TR_NESTED_TYPE(propagate_on_container_swap,
- false_type)
+ using propagate_on_container_move_assignment
+ = __detected_or_t<false_type, __pocma, _Alloc>;
/**
* @brief How the allocator is propagated on swap
* @c Alloc::propagate_on_container_swap if that type exists,
* otherwise @c false_type
*/
- typedef __propagate_on_container_swap propagate_on_container_swap;
+ using propagate_on_container_swap
+ = __detected_or_t<false_type, __pocs, _Alloc>;
-#undef _GLIBCXX_ALLOC_TR_NESTED_TYPE
+ /**
+ * @brief Whether all instances of the allocator type compare equal.
+ *
+ * @c Alloc::is_always_equal if that type exists,
+ * otherwise @c is_empty<Alloc>::type
+ */
+ using is_always_equal
+ = typename __detected_or_t<is_empty<_Alloc>, __equal, _Alloc>::type;
template<typename _Tp>
- using rebind_alloc = typename __alloctr_rebind<_Alloc, _Tp>::__type;
+ using rebind_alloc = __alloc_rebind<_Alloc, _Tp>;
template<typename _Tp>
- using rebind_traits = allocator_traits<rebind_alloc<_Tp>>;
+ using rebind_traits = allocator_traits<rebind_alloc<_Tp>>;
private:
template<typename _Alloc2>
- struct __allocate_helper
- {
- template<typename _Alloc3,
- typename = decltype(std::declval<_Alloc3*>()->allocate(
- std::declval<size_type>(),
- std::declval<const_void_pointer>()))>
- static true_type __test(int);
-
- template<typename>
- static false_type __test(...);
-
- typedef decltype(__test<_Alloc>(0)) type;
- static const bool value = type::value;
- };
-
- template<typename _Alloc2>
- static typename
- enable_if<__allocate_helper<_Alloc2>::value, pointer>::type
- _S_allocate(_Alloc2& __a, size_type __n, const_void_pointer __hint)
+ static constexpr auto
+ _S_allocate(_Alloc2& __a, size_type __n, const_void_pointer __hint, int)
+ -> decltype(__a.allocate(__n, __hint))
{ return __a.allocate(__n, __hint); }
template<typename _Alloc2>
- static typename
- enable_if<!__allocate_helper<_Alloc2>::value, pointer>::type
- _S_allocate(_Alloc2& __a, size_type __n, ...)
+ static constexpr pointer
+ _S_allocate(_Alloc2& __a, size_type __n, const_void_pointer, ...)
{ return __a.allocate(__n); }
template<typename _Tp, typename... _Args>
template<typename>
static false_type __test(...);
- typedef decltype(__test<_Alloc>(0)) type;
- static const bool value = type::value;
+ using type = decltype(__test<_Alloc>(0));
};
template<typename _Tp, typename... _Args>
- static typename
- enable_if<__construct_helper<_Tp, _Args...>::value, void>::type
- _S_construct(_Alloc& __a, _Tp* __p, _Args&&... __args)
- { __a.construct(__p, std::forward<_Args>(__args)...); }
+ using __has_construct
+ = typename __construct_helper<_Tp, _Args...>::type;
template<typename _Tp, typename... _Args>
- static typename
- enable_if<__and_<__not_<__construct_helper<_Tp, _Args...>>,
- is_constructible<_Tp, _Args...>>::value, void>::type
- _S_construct(_Alloc&, _Tp* __p, _Args&&... __args)
- { ::new((void*)__p) _Tp(std::forward<_Args>(__args)...); }
+ static _GLIBCXX14_CONSTEXPR _Require<__has_construct<_Tp, _Args...>>
+ _S_construct(_Alloc& __a, _Tp* __p, _Args&&... __args)
+ noexcept(noexcept(__a.construct(__p, std::forward<_Args>(__args)...)))
+ { __a.construct(__p, std::forward<_Args>(__args)...); }
- template<typename _Tp>
- struct __destroy_helper
+ template<typename _Tp, typename... _Args>
+ static _GLIBCXX14_CONSTEXPR
+ _Require<__and_<__not_<__has_construct<_Tp, _Args...>>,
+ is_constructible<_Tp, _Args...>>>
+ _S_construct(_Alloc&, _Tp* __p, _Args&&... __args)
+ noexcept(std::is_nothrow_constructible<_Tp, _Args...>::value)
{
- template<typename _Alloc2,
- typename = decltype(std::declval<_Alloc2*>()->destroy(
- std::declval<_Tp*>()))>
- static true_type __test(int);
-
- template<typename>
- static false_type __test(...);
-
- typedef decltype(__test<_Alloc>(0)) type;
- static const bool value = type::value;
- };
+#if __cplusplus <= 201703L
+ ::new((void*)__p) _Tp(std::forward<_Args>(__args)...);
+#else
+ std::construct_at(__p, std::forward<_Args>(__args)...);
+#endif
+ }
- template<typename _Tp>
- static typename enable_if<__destroy_helper<_Tp>::value, void>::type
- _S_destroy(_Alloc& __a, _Tp* __p)
+ template<typename _Alloc2, typename _Tp>
+ static _GLIBCXX14_CONSTEXPR auto
+ _S_destroy(_Alloc2& __a, _Tp* __p, int)
+ noexcept(noexcept(__a.destroy(__p)))
+ -> decltype(__a.destroy(__p))
{ __a.destroy(__p); }
- template<typename _Tp>
- static typename enable_if<!__destroy_helper<_Tp>::value, void>::type
- _S_destroy(_Alloc&, _Tp* __p)
- { __p->~_Tp(); }
+ template<typename _Alloc2, typename _Tp>
+ static _GLIBCXX14_CONSTEXPR void
+ _S_destroy(_Alloc2&, _Tp* __p, ...)
+ noexcept(std::is_nothrow_destructible<_Tp>::value)
+ { std::_Destroy(__p); }
template<typename _Alloc2>
- struct __maxsize_helper
- {
- template<typename _Alloc3,
- typename = decltype(std::declval<_Alloc3*>()->max_size())>
- static true_type __test(int);
-
- template<typename>
- static false_type __test(...);
-
- typedef decltype(__test<_Alloc2>(0)) type;
- static const bool value = type::value;
- };
-
- template<typename _Alloc2>
- static typename
- enable_if<__maxsize_helper<_Alloc2>::value, size_type>::type
- _S_max_size(_Alloc2& __a)
+ static constexpr auto
+ _S_max_size(_Alloc2& __a, int)
+ -> decltype(__a.max_size())
{ return __a.max_size(); }
template<typename _Alloc2>
- static typename
- enable_if<!__maxsize_helper<_Alloc2>::value, size_type>::type
- _S_max_size(_Alloc2&)
- { return __gnu_cxx::__numeric_traits<size_type>::__max; }
-
- template<typename _Alloc2>
- struct __select_helper
+ static constexpr size_type
+ _S_max_size(_Alloc2&, ...)
{
- template<typename _Alloc3, typename
- = decltype(std::declval<_Alloc3*>()
- ->select_on_container_copy_construction())>
- static true_type __test(int);
-
- template<typename>
- static false_type __test(...);
+ // _GLIBCXX_RESOLVE_LIB_DEFECTS
+ // 2466. allocator_traits::max_size() default behavior is incorrect
+ return __gnu_cxx::__numeric_traits<size_type>::__max
+ / sizeof(value_type);
+ }
- typedef decltype(__test<_Alloc2>(0)) type;
- static const bool value = type::value;
- };
template<typename _Alloc2>
- static typename
- enable_if<__select_helper<_Alloc2>::value, _Alloc2>::type
- _S_select(_Alloc2& __a)
+ static constexpr auto
+ _S_select(_Alloc2& __a, int)
+ -> decltype(__a.select_on_container_copy_construction())
{ return __a.select_on_container_copy_construction(); }
template<typename _Alloc2>
- static typename
- enable_if<!__select_helper<_Alloc2>::value, _Alloc2>::type
- _S_select(_Alloc2& __a)
+ static constexpr _Alloc2
+ _S_select(_Alloc2& __a, ...)
{ return __a; }
public:
*
* Calls @c a.allocate(n)
*/
- static pointer
+ _GLIBCXX_NODISCARD static _GLIBCXX20_CONSTEXPR pointer
allocate(_Alloc& __a, size_type __n)
{ return __a.allocate(__n); }
* Returns <tt> a.allocate(n, hint) </tt> if that expression is
* well-formed, otherwise returns @c a.allocate(n)
*/
- static pointer
+ _GLIBCXX_NODISCARD static _GLIBCXX20_CONSTEXPR pointer
allocate(_Alloc& __a, size_type __n, const_void_pointer __hint)
- { return _S_allocate(__a, __n, __hint); }
+ { return _S_allocate(__a, __n, __hint, 0); }
/**
* @brief Deallocate memory.
*
* Calls <tt> a.deallocate(p, n) </tt>
*/
- static void deallocate(_Alloc& __a, pointer __p, size_type __n)
+ static _GLIBCXX20_CONSTEXPR void
+ deallocate(_Alloc& __a, pointer __p, size_type __n)
{ __a.deallocate(__p, __n); }
/**
- * @brief Construct an object of type @a _Tp
+ * @brief Construct an object of type `_Tp`
* @param __a An allocator.
* @param __p Pointer to memory of suitable size and alignment for Tp
* @param __args Constructor arguments.
* arguments @a __args...
*/
template<typename _Tp, typename... _Args>
- static auto construct(_Alloc& __a, _Tp* __p, _Args&&... __args)
+ static _GLIBCXX20_CONSTEXPR auto
+ construct(_Alloc& __a, _Tp* __p, _Args&&... __args)
+ noexcept(noexcept(_S_construct(__a, __p,
+ std::forward<_Args>(__args)...)))
-> decltype(_S_construct(__a, __p, std::forward<_Args>(__args)...))
{ _S_construct(__a, __p, std::forward<_Args>(__args)...); }
* Calls @c __a.destroy(__p) if that expression is well-formed,
* otherwise calls @c __p->~_Tp()
*/
- template <class _Tp>
- static void destroy(_Alloc& __a, _Tp* __p)
- { _S_destroy(__a, __p); }
+ template<typename _Tp>
+ static _GLIBCXX20_CONSTEXPR void
+ destroy(_Alloc& __a, _Tp* __p)
+ noexcept(noexcept(_S_destroy(__a, __p, 0)))
+ { _S_destroy(__a, __p, 0); }
/**
* @brief The maximum supported allocation size
* Returns @c __a.max_size() if that expression is well-formed,
* otherwise returns @c numeric_limits<size_type>::max()
*/
- static size_type max_size(const _Alloc& __a)
- { return _S_max_size(__a); }
+ static _GLIBCXX20_CONSTEXPR size_type
+ max_size(const _Alloc& __a) noexcept
+ { return _S_max_size(__a, 0); }
/**
* @brief Obtain an allocator to use when copying a container.
* Returns @c __rhs.select_on_container_copy_construction() if that
* expression is well-formed, otherwise returns @a __rhs
*/
- static _Alloc
+ static _GLIBCXX20_CONSTEXPR _Alloc
select_on_container_copy_construction(const _Alloc& __rhs)
- { return _S_select(__rhs); }
+ { return _S_select(__rhs, 0); }
};
- template<typename _Alloc>
- template<typename _Alloc2>
- const bool allocator_traits<_Alloc>::__allocate_helper<_Alloc2>::value;
+#if _GLIBCXX_HOSTED
+ /// Partial specialization for std::allocator.
+ template<typename _Tp>
+ struct allocator_traits<allocator<_Tp>>
+ {
+ /// The allocator type
+ using allocator_type = allocator<_Tp>;
- template<typename _Alloc>
- template<typename _Tp, typename... _Args>
- const bool
- allocator_traits<_Alloc>::__construct_helper<_Tp, _Args...>::value;
+ /// The allocated type
+ using value_type = _Tp;
- template<typename _Alloc>
- template<typename _Tp>
- const bool allocator_traits<_Alloc>::__destroy_helper<_Tp>::value;
+ /// The allocator's pointer type.
+ using pointer = _Tp*;
- template<typename _Alloc>
- template<typename _Alloc2>
- const bool allocator_traits<_Alloc>::__maxsize_helper<_Alloc2>::value;
+ /// The allocator's const pointer type.
+ using const_pointer = const _Tp*;
- template<typename _Alloc>
- template<typename _Alloc2>
- const bool allocator_traits<_Alloc>::__select_helper<_Alloc2>::value;
+ /// The allocator's void pointer type.
+ using void_pointer = void*;
+
+ /// The allocator's const void pointer type.
+ using const_void_pointer = const void*;
+
+ /// The allocator's difference type
+ using difference_type = std::ptrdiff_t;
+
+ /// The allocator's size type
+ using size_type = std::size_t;
+
+ /// How the allocator is propagated on copy assignment
+ using propagate_on_container_copy_assignment = false_type;
+
+ /// How the allocator is propagated on move assignment
+ using propagate_on_container_move_assignment = true_type;
+
+ /// How the allocator is propagated on swap
+ using propagate_on_container_swap = false_type;
+
+ /// Whether all instances of the allocator type compare equal.
+ using is_always_equal = true_type;
+
+ template<typename _Up>
+ using rebind_alloc = allocator<_Up>;
+
+ template<typename _Up>
+ using rebind_traits = allocator_traits<allocator<_Up>>;
+
+ /**
+ * @brief Allocate memory.
+ * @param __a An allocator.
+ * @param __n The number of objects to allocate space for.
+ *
+ * Calls @c a.allocate(n)
+ */
+ [[__nodiscard__,__gnu__::__always_inline__]]
+ static _GLIBCXX20_CONSTEXPR pointer
+ allocate(allocator_type& __a, size_type __n)
+ { return __a.allocate(__n); }
+
+ /**
+ * @brief Allocate memory.
+ * @param __a An allocator.
+ * @param __n The number of objects to allocate space for.
+ * @param __hint Aid to locality.
+ * @return Memory of suitable size and alignment for @a n objects
+ * of type @c value_type
+ *
+ * Returns <tt> a.allocate(n, hint) </tt>
+ */
+ [[__nodiscard__,__gnu__::__always_inline__]]
+ static _GLIBCXX20_CONSTEXPR pointer
+ allocate(allocator_type& __a, size_type __n,
+ [[maybe_unused]] const_void_pointer __hint)
+ {
+#if __cplusplus <= 201703L
+ return __a.allocate(__n, __hint);
+#else
+ return __a.allocate(__n);
+#endif
+ }
+
+ /**
+ * @brief Deallocate memory.
+ * @param __a An allocator.
+ * @param __p Pointer to the memory to deallocate.
+ * @param __n The number of objects space was allocated for.
+ *
+ * Calls <tt> a.deallocate(p, n) </tt>
+ */
+ [[__gnu__::__always_inline__]]
+ static _GLIBCXX20_CONSTEXPR void
+ deallocate(allocator_type& __a, pointer __p, size_type __n)
+ { __a.deallocate(__p, __n); }
+ /**
+ * @brief Construct an object of type `_Up`
+ * @param __a An allocator.
+ * @param __p Pointer to memory of suitable size and alignment for
+ * an object of type `_Up`.
+ * @param __args Constructor arguments.
+ *
+ * Calls `__a.construct(__p, std::forward<_Args>(__args)...)`
+ * in C++11, C++14 and C++17. Changed in C++20 to call
+ * `std::construct_at(__p, std::forward<_Args>(__args)...)` instead.
+ */
+ template<typename _Up, typename... _Args>
+ [[__gnu__::__always_inline__]]
+ static _GLIBCXX20_CONSTEXPR void
+ construct(allocator_type& __a __attribute__((__unused__)), _Up* __p,
+ _Args&&... __args)
+ noexcept(std::is_nothrow_constructible<_Up, _Args...>::value)
+ {
+#if __cplusplus <= 201703L
+ __a.construct(__p, std::forward<_Args>(__args)...);
+#else
+ std::construct_at(__p, std::forward<_Args>(__args)...);
+#endif
+ }
+
+ /**
+ * @brief Destroy an object of type @a _Up
+ * @param __a An allocator.
+ * @param __p Pointer to the object to destroy
+ *
+ * Calls @c __a.destroy(__p).
+ */
+ template<typename _Up>
+ [[__gnu__::__always_inline__]]
+ static _GLIBCXX20_CONSTEXPR void
+ destroy(allocator_type& __a __attribute__((__unused__)), _Up* __p)
+ noexcept(is_nothrow_destructible<_Up>::value)
+ {
+#if __cplusplus <= 201703L
+ __a.destroy(__p);
+#else
+ std::destroy_at(__p);
+#endif
+ }
+
+ /**
+ * @brief The maximum supported allocation size
+ * @param __a An allocator.
+ * @return @c __a.max_size()
+ */
+ [[__gnu__::__always_inline__]]
+ static _GLIBCXX20_CONSTEXPR size_type
+ max_size(const allocator_type& __a __attribute__((__unused__))) noexcept
+ {
+#if __cplusplus <= 201703L
+ return __a.max_size();
+#else
+ return size_t(-1) / sizeof(value_type);
+#endif
+ }
+
+ /**
+ * @brief Obtain an allocator to use when copying a container.
+ * @param __rhs An allocator.
+ * @return @c __rhs
+ */
+ [[__gnu__::__always_inline__]]
+ static _GLIBCXX20_CONSTEXPR allocator_type
+ select_on_container_copy_construction(const allocator_type& __rhs)
+ { return __rhs; }
+ };
+
+ /// Explicit specialization for std::allocator<void>.
+ template<>
+ struct allocator_traits<allocator<void>>
+ {
+ /// The allocator type
+ using allocator_type = allocator<void>;
+
+ /// The allocated type
+ using value_type = void;
+
+ /// The allocator's pointer type.
+ using pointer = void*;
+
+ /// The allocator's const pointer type.
+ using const_pointer = const void*;
+
+ /// The allocator's void pointer type.
+ using void_pointer = void*;
+
+ /// The allocator's const void pointer type.
+ using const_void_pointer = const void*;
+
+ /// The allocator's difference type
+ using difference_type = std::ptrdiff_t;
+
+ /// The allocator's size type
+ using size_type = std::size_t;
+
+ /// How the allocator is propagated on copy assignment
+ using propagate_on_container_copy_assignment = false_type;
+
+ /// How the allocator is propagated on move assignment
+ using propagate_on_container_move_assignment = true_type;
+
+ /// How the allocator is propagated on swap
+ using propagate_on_container_swap = false_type;
+
+ /// Whether all instances of the allocator type compare equal.
+ using is_always_equal = true_type;
+
+ template<typename _Up>
+ using rebind_alloc = allocator<_Up>;
+
+ template<typename _Up>
+ using rebind_traits = allocator_traits<allocator<_Up>>;
+
+ /// allocate is ill-formed for allocator<void>
+ static void*
+ allocate(allocator_type&, size_type, const void* = nullptr) = delete;
+
+ /// deallocate is ill-formed for allocator<void>
+ static void
+ deallocate(allocator_type&, void*, size_type) = delete;
+
+ /**
+ * @brief Construct an object of type `_Up`
+ * @param __a An allocator.
+ * @param __p Pointer to memory of suitable size and alignment for
+ * an object of type `_Up`.
+ * @param __args Constructor arguments.
+ *
+ * Calls `__a.construct(__p, std::forward<_Args>(__args)...)`
+ * in C++11, C++14 and C++17. Changed in C++20 to call
+ * `std::construct_at(__p, std::forward<_Args>(__args)...)` instead.
+ */
+ template<typename _Up, typename... _Args>
+ [[__gnu__::__always_inline__]]
+ static _GLIBCXX20_CONSTEXPR void
+ construct(allocator_type&, _Up* __p, _Args&&... __args)
+ noexcept(std::is_nothrow_constructible<_Up, _Args...>::value)
+ { std::_Construct(__p, std::forward<_Args>(__args)...); }
+
+ /**
+ * @brief Destroy an object of type `_Up`
+ * @param __a An allocator.
+ * @param __p Pointer to the object to destroy
+ *
+ * Invokes the destructor for `*__p`.
+ */
+ template<typename _Up>
+ [[__gnu__::__always_inline__]]
+ static _GLIBCXX20_CONSTEXPR void
+ destroy(allocator_type&, _Up* __p)
+ noexcept(is_nothrow_destructible<_Up>::value)
+ { std::_Destroy(__p); }
+
+ /// max_size is ill-formed for allocator<void>
+ static size_type
+ max_size(const allocator_type&) = delete;
+
+ /**
+ * @brief Obtain an allocator to use when copying a container.
+ * @param __rhs An allocator.
+ * @return `__rhs`
+ */
+ [[__gnu__::__always_inline__]]
+ static _GLIBCXX20_CONSTEXPR allocator_type
+ select_on_container_copy_construction(const allocator_type& __rhs)
+ { return __rhs; }
+ };
+#endif
+
+ /// @cond undocumented
+#if __cplusplus < 201703L
template<typename _Alloc>
+ [[__gnu__::__always_inline__]]
inline void
__do_alloc_on_copy(_Alloc& __one, const _Alloc& __two, true_type)
{ __one = __two; }
template<typename _Alloc>
+ [[__gnu__::__always_inline__]]
inline void
__do_alloc_on_copy(_Alloc&, const _Alloc&, false_type)
{ }
+#endif
template<typename _Alloc>
- inline void __alloc_on_copy(_Alloc& __one, const _Alloc& __two)
+ [[__gnu__::__always_inline__]]
+ _GLIBCXX14_CONSTEXPR inline void
+ __alloc_on_copy(_Alloc& __one, const _Alloc& __two)
{
- typedef allocator_traits<_Alloc> __traits;
- typedef typename __traits::propagate_on_container_copy_assignment __pocca;
+ using __traits = allocator_traits<_Alloc>;
+ using __pocca =
+ typename __traits::propagate_on_container_copy_assignment::type;
+#if __cplusplus >= 201703L
+ if constexpr (__pocca::value)
+ __one = __two;
+#else
__do_alloc_on_copy(__one, __two, __pocca());
+#endif
}
template<typename _Alloc>
- inline _Alloc __alloc_on_copy(const _Alloc& __a)
+ [[__gnu__::__always_inline__]]
+ constexpr _Alloc
+ __alloc_on_copy(const _Alloc& __a)
{
typedef allocator_traits<_Alloc> __traits;
return __traits::select_on_container_copy_construction(__a);
}
+#if __cplusplus < 201703L
template<typename _Alloc>
+ [[__gnu__::__always_inline__]]
inline void __do_alloc_on_move(_Alloc& __one, _Alloc& __two, true_type)
{ __one = std::move(__two); }
template<typename _Alloc>
+ [[__gnu__::__always_inline__]]
inline void __do_alloc_on_move(_Alloc&, _Alloc&, false_type)
{ }
+#endif
template<typename _Alloc>
- inline void __alloc_on_move(_Alloc& __one, _Alloc& __two)
+ [[__gnu__::__always_inline__]]
+ _GLIBCXX14_CONSTEXPR inline void
+ __alloc_on_move(_Alloc& __one, _Alloc& __two)
{
- typedef allocator_traits<_Alloc> __traits;
- typedef typename __traits::propagate_on_container_move_assignment __pocma;
+ using __traits = allocator_traits<_Alloc>;
+ using __pocma
+ = typename __traits::propagate_on_container_move_assignment::type;
+#if __cplusplus >= 201703L
+ if constexpr (__pocma::value)
+ __one = std::move(__two);
+#else
__do_alloc_on_move(__one, __two, __pocma());
+#endif
}
+#if __cplusplus < 201703L
template<typename _Alloc>
+ [[__gnu__::__always_inline__]]
inline void __do_alloc_on_swap(_Alloc& __one, _Alloc& __two, true_type)
{
using std::swap;
}
template<typename _Alloc>
+ [[__gnu__::__always_inline__]]
inline void __do_alloc_on_swap(_Alloc&, _Alloc&, false_type)
{ }
+#endif
template<typename _Alloc>
- inline void __alloc_on_swap(_Alloc& __one, _Alloc& __two)
+ [[__gnu__::__always_inline__]]
+ _GLIBCXX14_CONSTEXPR inline void
+ __alloc_on_swap(_Alloc& __one, _Alloc& __two)
{
- typedef allocator_traits<_Alloc> __traits;
- typedef typename __traits::propagate_on_container_swap __pocs;
+ using __traits = allocator_traits<_Alloc>;
+ using __pocs = typename __traits::propagate_on_container_swap::type;
+#if __cplusplus >= 201703L
+ if constexpr (__pocs::value)
+ {
+ using std::swap;
+ swap(__one, __two);
+ }
+#else
__do_alloc_on_swap(__one, __two, __pocs());
+#endif
}
- template<typename _Alloc>
- class __is_copy_insertable_impl
- {
- typedef allocator_traits<_Alloc> _Traits;
-
- template<typename _Up, typename
- = decltype(_Traits::construct(std::declval<_Alloc&>(),
- std::declval<_Up*>(),
- std::declval<const _Up&>()))>
- static true_type
- _M_select(int);
-
- template<typename _Up>
- static false_type
- _M_select(...);
+ template<typename _Alloc, typename _Tp,
+ typename _ValueT = __remove_cvref_t<typename _Alloc::value_type>,
+ typename = void>
+ struct __is_alloc_insertable_impl
+ : false_type
+ { };
- public:
- typedef decltype(_M_select<typename _Alloc::value_type>(0)) type;
- };
+ template<typename _Alloc, typename _Tp, typename _ValueT>
+ struct __is_alloc_insertable_impl<_Alloc, _Tp, _ValueT,
+ __void_t<decltype(allocator_traits<_Alloc>::construct(
+ std::declval<_Alloc&>(), std::declval<_ValueT*>(),
+ std::declval<_Tp>()))>>
+ : true_type
+ { };
// true if _Alloc::value_type is CopyInsertable into containers using _Alloc
+ // (might be wrong if _Alloc::construct exists but is not constrained,
+ // i.e. actually trying to use it would still be invalid. Use with caution.)
template<typename _Alloc>
struct __is_copy_insertable
- : __is_copy_insertable_impl<_Alloc>::type
+ : __is_alloc_insertable_impl<_Alloc,
+ typename _Alloc::value_type const&>::type
{ };
+#if _GLIBCXX_HOSTED
// std::allocator<_Tp> just requires CopyConstructible
template<typename _Tp>
struct __is_copy_insertable<allocator<_Tp>>
: is_copy_constructible<_Tp>
{ };
+#endif
- // Used to allow copy construction of unordered containers
- template<bool> struct __allow_copy_cons { };
+ // true if _Alloc::value_type is MoveInsertable into containers using _Alloc
+ // (might be wrong if _Alloc::construct exists but is not constrained,
+ // i.e. actually trying to use it would still be invalid. Use with caution.)
+ template<typename _Alloc>
+ struct __is_move_insertable
+ : __is_alloc_insertable_impl<_Alloc, typename _Alloc::value_type>::type
+ { };
- // Used to delete copy constructor of unordered containers
- template<>
- struct __allow_copy_cons<false>
- {
- __allow_copy_cons() = default;
- __allow_copy_cons(const __allow_copy_cons&) = delete;
- __allow_copy_cons(__allow_copy_cons&&) = default;
- __allow_copy_cons& operator=(const __allow_copy_cons&) = default;
- __allow_copy_cons& operator=(__allow_copy_cons&&) = default;
+#if _GLIBCXX_HOSTED
+ // std::allocator<_Tp> just requires MoveConstructible
+ template<typename _Tp>
+ struct __is_move_insertable<allocator<_Tp>>
+ : is_move_constructible<_Tp>
+ { };
+#endif
+
+ // Trait to detect Allocator-like types.
+ template<typename _Alloc, typename = void>
+ struct __is_allocator : false_type { };
+
+ template<typename _Alloc>
+ struct __is_allocator<_Alloc,
+ __void_t<typename _Alloc::value_type,
+ decltype(std::declval<_Alloc&>().allocate(size_t{}))>>
+ : true_type { };
+
+ template<typename _Alloc>
+ using _RequireAllocator
+ = typename enable_if<__is_allocator<_Alloc>::value, _Alloc>::type;
+
+ template<typename _Alloc>
+ using _RequireNotAllocator
+ = typename enable_if<!__is_allocator<_Alloc>::value, _Alloc>::type;
+
+#if __cpp_concepts >= 201907L
+ template<typename _Alloc>
+ concept __allocator_like = requires (_Alloc& __a) {
+ typename _Alloc::value_type;
+ __a.deallocate(__a.allocate(1u), 1u);
};
+#endif
+ /// @endcond
+#endif // C++11
+
+ /// @cond undocumented
+
+ // To implement Option 3 of DR 431.
+ template<typename _Alloc, bool = __is_empty(_Alloc)>
+ struct __alloc_swap
+ { static void _S_do_it(_Alloc&, _Alloc&) _GLIBCXX_NOEXCEPT { } };
template<typename _Alloc>
- using __check_copy_constructible
- = __allow_copy_cons<__is_copy_insertable<_Alloc>::value>;
+ struct __alloc_swap<_Alloc, false>
+ {
+ static void
+ _S_do_it(_Alloc& __one, _Alloc& __two) _GLIBCXX_NOEXCEPT
+ {
+ // Precondition: swappable allocators.
+ if (__one != __two)
+ swap(__one, __two);
+ }
+ };
-_GLIBCXX_END_NAMESPACE_VERSION
-} // namespace std
+#if __cplusplus >= 201103L
+ template<typename _Tp, bool
+ = __or_<is_copy_constructible<typename _Tp::value_type>,
+ is_nothrow_move_constructible<typename _Tp::value_type>>::value>
+ struct __shrink_to_fit_aux
+ { static bool _S_do_it(_Tp&) noexcept { return false; } };
+ template<typename _Tp>
+ struct __shrink_to_fit_aux<_Tp, true>
+ {
+ _GLIBCXX20_CONSTEXPR
+ static bool
+ _S_do_it(_Tp& __c) noexcept
+ {
+#if __cpp_exceptions
+ try
+ {
+ _Tp(__make_move_if_noexcept_iterator(__c.begin()),
+ __make_move_if_noexcept_iterator(__c.end()),
+ __c.get_allocator()).swap(__c);
+ return true;
+ }
+ catch(...)
+ { return false; }
+#else
+ return false;
+#endif
+ }
+ };
+#endif
+
+ /**
+ * Destroy a range of objects using the supplied allocator. For
+ * non-default allocators we do not optimize away invocation of
+ * destroy() even if _Tp has a trivial destructor.
+ */
+
+ template<typename _ForwardIterator, typename _Allocator>
+ _GLIBCXX20_CONSTEXPR
+ void
+ _Destroy(_ForwardIterator __first, _ForwardIterator __last,
+ _Allocator& __alloc)
+ {
+ for (; __first != __last; ++__first)
+#if __cplusplus < 201103L
+ __alloc.destroy(std::__addressof(*__first));
+#else
+ allocator_traits<_Allocator>::destroy(__alloc,
+ std::__addressof(*__first));
#endif
+ }
+
+#if _GLIBCXX_HOSTED
+ template<typename _ForwardIterator, typename _Tp>
+ __attribute__((__always_inline__)) _GLIBCXX20_CONSTEXPR
+ inline void
+ _Destroy(_ForwardIterator __first, _ForwardIterator __last,
+ allocator<_Tp>&)
+ {
+ std::_Destroy(__first, __last);
+ }
#endif
+ /// @endcond
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+#endif // _ALLOC_TRAITS_H
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