编写自己的MemoryAllocator

allocator

class template

<memory>

template <class T> class allocator;

Default allocator

Allocators are classes that define memory models to be used by some parts of the Standard Library, and most specifically, by  STL containers .

This section describes the  default allocator template   allocator  (lowercase). This is the allocator that all standard containers will use if their last (and optional) template parameter is not specified, and is the only predefined allocator in the standard library.

Other allocators may be defined. Any class having the same members as this  default allocator  and following its minimum requirements can be used as an allocator -- notice that only under very specific circumstances this is needed.

Technically, a memory model described by allocators might be specialized for each type of object to be allocated and even may store local data for each container they work with. Although this does not happen with the default  allocator .

The class template of  allocator  is declared as:

template < class T > class allocator;

Taking one template parameter (which is assumed to be  T  in this entire reference).

Member types

member	definition in allocator	represents
value_type	T	Element type
pointer	T*	Pointer to element
reference	T&	Reference to element
const_pointer	const T*	Constant pointer to element
const_reference	const T&	Constant reference to element
size_type	size_t	Quantities of elements
difference_type	ptrdiff_t	Difference between two pointers

Member functions

(constructor)

Construct allocator object (public member function)

(destructor)

Allocator destructor (public member function)

address

Return address (public member function)

allocate

Allocate block of storage (public member function)

deallocate

Release block of storage (public member function)

max_size

Maximum size possible to allocate (public member function)

construct

Construct an object (public member function)

destroy

Destroy an object (public member function)