std_allocator< T, RawAllocator > Class Template Reference

Detailed Description

template<typename T, class RawAllocator>
class foonathan::memory::std_allocator< T, RawAllocator >

Wraps a RawAllocator and makes it a "normal" Allocator.

It allows using a RawAllocator anywhere a Allocator is required.

Typedefs
using	value_type = T
using	pointer = T *
using	const_pointer = const T *
using	reference = T &
using	const_reference = const T &
using	size_type = std::size_t
using	difference_type = std::ptrdiff_t
using	propagate_on_container_swap = typename prop_traits::propagate_on_container_swap
using	propagate_on_container_move_assignment = typename prop_traits::propagate_on_container_move_assignment
using	propagate_on_container_copy_assignment = typename prop_traits::propagate_on_container_copy_assignment
using	allocator_type = typename alloc_reference::allocator_type

Member Functions
	std_allocator () noexcept
template<class RawAlloc >
	std_allocator (RawAlloc &alloc,) noexcept
template<class RawAlloc >
	std_allocator (const RawAlloc &alloc,) noexcept
	std_allocator (const alloc_reference &alloc) noexcept
template<class StoragePolicy , class OtherMut >
	std_allocator (const allocator_storage< StoragePolicy, OtherMut > &)=delete
std_allocator< T, RawAllocator >	select_on_container_copy_construction () const
pointer	allocate (size_type n, void *=nullptr)
void	deallocate (pointer p, size_type n) noexcept
template<typename U , typename... Args>
void	construct (U *p, Args &&... args)
template<typename U >
void	destroy (U *p) noexcept
size_type	max_size () const noexcept
template<typename U >
	std_allocator (const std_allocator< U, RawAllocator > &alloc) noexcept
template<typename U >
	std_allocator (std_allocator< U, RawAllocator > &alloc) noexcept
auto	get_allocator () noexcept -> decltype(std::declval< alloc_reference >().get_allocator())
auto	get_allocator () const noexcept -> decltype(std::declval< const alloc_reference >().get_allocator())

Related Functions
template<typename T , typename U , class Impl >
bool	operator== (const std_allocator< T, Impl > &lhs, const std_allocator< U, Impl > &rhs) noexcept
template<typename T , typename U , class Impl >
bool	operator!= (const std_allocator< T, Impl > &lhs, const std_allocator< U, Impl > &rhs) noexcept
template<typename T , class RawAllocator >
auto	make_std_allocator (RawAllocator &&allocator) noexcept -> std_allocator< T, typename std::decay< RawAllocator >::type >

Constructors

std_allocator() [1/7]

std_allocator ( )

noexcept

Effects:

Default constructs it by storing a default constructed, stateless RawAllocator inside the reference.

Requires:

The RawAllocator type is stateless, otherwise the body of this function will not compile.

std_allocator() [2/7]

std_allocator ( RawAlloc &  alloc )

noexcept

Effects:

Creates it from a reference to a RawAllocator. It will store an allocator_reference to it.

Requires:

The expression allocator_reference<RawAllocator>(alloc) is well-formed, that is either RawAlloc is the same as RawAllocator or RawAllocator is the tag type any_allocator. If the requirement is not fulfilled this function does not participate in overload resolution.

Note

The caller has to ensure that the lifetime of the RawAllocator is at least as long as the lifetime of this std_allocator object.

std_allocator() [3/7]

std_allocator ( const RawAlloc &  alloc )

noexcept

Effects:

Creates it from a stateless, temporary RawAllocator object. It will not store a reference but create it on the fly.

Requires:

The RawAllocator is stateless and the expression allocator_reference<RawAllocator>(alloc) is well-formed as above, otherwise this function does not participate in overload resolution.

std_allocator() [4/7]

std_allocator ( const alloc_reference &  alloc )

noexcept

Effects:

Creates it from another allocator_reference using the same allocator type.

std_allocator() [5/7]

std_allocator ( const allocator_storage< StoragePolicy, OtherMut > &  )

delete

Implicit conversion from any other allocator_storage is forbidden to prevent accidentally wrapping another allocator_storage inside a allocator_reference.

std_allocator() [6/7]

std_allocator ( const std_allocator< U, RawAllocator > &  alloc )

noexcept

Effects:

Creates it from another std_allocator allocating a different type. This is required by the Allcoator concept and simply takes the same allocator_reference.

std_allocator() [7/7]

std_allocator ( std_allocator< U, RawAllocator > &  alloc )

noexcept

Effects:

Creates it from another std_allocator allocating a different type. This is required by the Allcoator concept and simply takes the same allocator_reference.

Member Functions

select_on_container_copy_construction()

std_allocator< T, RawAllocator > select_on_container_copy_construction

(

)

const

Returns:

A copy of the allocator. This is required by the Allocator concept and forwards to the propagation_traits.

allocate()

pointer allocate	(	size_type	n,
		void *	= nullptr
	)

Effects:

Allocates memory using the underlying RawAllocator. If n is 1, it will call allocate_node(sizeof(T), alignof(T)), otherwise allocate_array(n, sizeof(T), alignof(T)).

Returns:

A pointer to a memory block suitable for n objects of type T.

Throws:

Anything thrown by the RawAllocator.

deallocate()

void deallocate ( pointer  p, size_type  n  )

noexcept

Effects:

Deallcoates memory using the underlying RawAllocator. It will forward to the deallocation function in the same way as in allocate().

Requires:

The pointer must come from a previous call to allocate() with the same n on this object or any copy of it.

construct()

void construct	(	U *	p,
		Args &&...	args
	)

Effects:

Creates an object of type U at given address using the passed arguments.

destroy()

void destroy ( U *  p )

noexcept

Effects:

Calls the destructor for an object of type U at given address.

max_size()

size_type max_size ( ) const

noexcept

Returns:

The maximum size for an allocation which is max_array_size() / sizeof(value_type). This is only an upper bound, not the exact maximum.

get_allocator() [1/2]

auto get_allocator ( ) -> decltype(std::declval<alloc_reference>().get_allocator())

noexcept

Effects:

Returns a reference to the referenced allocator.

Returns:

For stateful allocators: A (const) reference to the stored allocator. For stateless allocators: A temporary constructed allocator.

get_allocator() [2/2]

auto get_allocator ( ) const -> decltype(std::declval<const alloc_reference>().get_allocator())

noexcept

Effects:

Returns a reference to the referenced allocator.

Returns:

For stateful allocators: A (const) reference to the stored allocator. For stateless allocators: A temporary constructed allocator.

Related Functions

operator==()

bool operator== ( const std_allocator< T, Impl > &  lhs, const std_allocator< U, Impl > &  rhs  )

related

Effects:

Compares two std_allocator object, they are equal if either stateless or reference the same allocator.

Returns:

The result of the comparision for equality.

operator!=()

bool operator!= ( const std_allocator< T, Impl > &  lhs, const std_allocator< U, Impl > &  rhs  )

related

Effects:

Compares two std_allocator object, they are equal if either stateless or reference the same allocator.

Returns:

The result of the comparision for inequality.

make_std_allocator()

auto make_std_allocator ( RawAllocator &&  allocator ) -> std_allocator<T, typename std::decay<RawAllocator>::type>

related

Returns:

A new std_allocator for a given type using a certain allocator object.