Difference between revisions of "cpp/experimental/resource adaptor"
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(Create. Could probably use some polishing) |
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| − | {{ | + | {{title|{{small|std::experimental::pmr::}}resource_adaptor, {{small|std::pmr::experimental::}}resource_adaptor}} |
{{cpp/experimental/lib extensions/pmr/navbar}} | {{cpp/experimental/lib extensions/pmr/navbar}} | ||
| + | {{dcl begin}} | ||
| + | {{dcl header | experimental/memory_resource}} | ||
| + | {{dcl | since=libfund_ts | 1= | ||
| + | template< class Alloc > | ||
| + | using resource_adaptor = /*resource-adaptor-imp*/< | ||
| + | typename std::allocator_traits<Alloc>:: | ||
| + | template rebind_alloc<char>>; | ||
| + | }} | ||
| + | {{dcl | since=libfund_ts | | ||
| + | template< class Alloc > | ||
| + | class /*resource-adaptor-imp*/ : public memory_resource; // for exposition only | ||
| + | }} | ||
| + | {{dcl end}} | ||
| − | {{ | + | The alias template {{tt|resource_adaptor}} adapts the allocator type {{tt|Alloc}} with a {{tt|memory_resource}} interface. The allocator is rebound to a {{tt|char}} value type before it is actually adapted (using the ''{{tt|resource-adaptor-imp}}'' class template), so that adapting specializations of the same allocator template always yields the same type, regardless of the value type the allocator template is originally instantiated with. |
| − | + | ||
| − | + | ||
| − | + | {{rrev multi | |
| − | + | |since1=libfund_ts|rev1= | |
| − | + | {{tt|resource_adaptor}} is defined in namespace {{tt|std::experimental::pmr}}, and the base type {{tt|memory_resorce}} in this page is {{lc|std::experimental::pmr::memory_resource}}. | |
| − | + | |since2=libfund_ts_3|rev2= | |
| + | {{tt|resource_adaptor}} is defined in namespace {{tt|std::pmr::experimental}}, and the base type {{tt|memory_resorce}} in this page is {{lc|std::pmr::memory_resource}}. | ||
}} | }} | ||
| − | + | ''{{tt|resource-adaptor-imp}}'' is a class template whose members are described below. The name ''{{tt|resource-adaptor-imp}}'' is for exposition purposes only and not normative. | |
| + | |||
| + | In addition to meeting the {{named req|Allocator}} requirements, {{tt|Alloc}} must additionally satisfy the following requirements: | ||
| + | |||
| + | * {{c|std::allocator_traits<Alloc>::pointer}} shall be identical to {{c|Alloc::value_type*}}. | ||
| + | * {{c|std::allocator_traits<Alloc>::const_pointer}} shall be identical to {{c|Alloc::value_type const*}}. | ||
| + | * {{c|std::allocator_traits<Alloc>::void_pointer}} shall be identical to {{c|void*}}. | ||
| + | * {{c|std::allocator_traits<Alloc>::const_const_pointer}} shall be identical to {{c|void const*}}. | ||
| − | === Member types of '' | + | ===Member types of ''resource-adaptor-imp''=== |
{{dsc begin}} | {{dsc begin}} | ||
{{dsc hitem| Member type | Definition}} | {{dsc hitem| Member type | Definition}} | ||
| Line 20: | Line 39: | ||
{{dsc end}} | {{dsc end}} | ||
| − | === Member functions of '' | + | ===Member functions of ''resource-adaptor-imp''=== |
| − | {{member|{{small| | + | {{member|{{small|''resource-adaptor-imp''::}}''resource-adaptor-imp'' |
| | | | ||
{{dcl begin}} | {{dcl begin}} | ||
{{dcl| num = 1 | since=libfund_ts |1= | {{dcl| num = 1 | since=libfund_ts |1= | ||
| − | + | /*resource-adaptor-imp*/() = default; | |
}} | }} | ||
{{dcl | num = 2 | since=libfund_ts |1= | {{dcl | num = 2 | since=libfund_ts |1= | ||
| − | + | /*resource-adaptor-imp*/(const /*resource-adaptor-imp*/& other) | |
| + | = default; | ||
}} | }} | ||
{{dcl | num = 3 | since=libfund_ts |1= | {{dcl | num = 3 | since=libfund_ts |1= | ||
| − | + | /*resource-adaptor-imp*/(/*resource-adaptor-imp*/&& other) | |
| + | = default; | ||
}} | }} | ||
{{dcl | num = 4 | since=libfund_ts |1= | {{dcl | num = 4 | since=libfund_ts |1= | ||
| − | + | explicit /*resource-adaptor-imp*/(const Alloc& a2); | |
}} | }} | ||
{{dcl | num = 5 | since=libfund_ts |1= | {{dcl | num = 5 | since=libfund_ts |1= | ||
| − | + | explicit /*resource-adaptor-imp*/(Alloc&& a2); | |
}} | }} | ||
{{dcl end}} | {{dcl end}} | ||
| Line 48: | Line 69: | ||
====Parameters==== | ====Parameters==== | ||
{{par begin}} | {{par begin}} | ||
| − | {{par | other | another ''{{tt| | + | {{par | other | another ''{{tt|resource-adaptor-imp}}'' object to copy or move from }} |
| − | {{par | a2 | another {{tt| | + | {{par | a2 | another {{tt|Alloc}} object to copy or move from }} |
{{par end}} | {{par end}} | ||
}} | }} | ||
| − | {{member|{{small| | + | {{member|{{small|''resource-adaptor-imp''::}}get_allocator |
| | | | ||
{{ddcl | since=libfund_ts |1= | {{ddcl | since=libfund_ts |1= | ||
| − | + | allocator_type get_allocator() const; | |
}} | }} | ||
Returns a copy of the wrapped allocator. | Returns a copy of the wrapped allocator. | ||
}} | }} | ||
| − | {{member|{{small| | + | {{member|{{small|''resource-adaptor-imp''::}}operator{{=}} |
| | | | ||
{{ddcl | since=libfund_ts |1= | {{ddcl | since=libfund_ts |1= | ||
| − | + | /*resource-adaptor-imp*/& operator=(const /*resource-adaptor-imp*/& other) | |
| + | = default; | ||
}} | }} | ||
Defaulted copy assignment operator. Copy assigns the wrapped allocator from that of {{tt|other}}. | Defaulted copy assignment operator. Copy assigns the wrapped allocator from that of {{tt|other}}. | ||
}} | }} | ||
| − | {{member|{{small| | + | {{member|{{small|''resource-adaptor-imp''::}}do_allocate |
| | | | ||
{{ddcl | since=libfund_ts |1= | {{ddcl | since=libfund_ts |1= | ||
| − | + | protected: | |
| + | virtual void* do_allocate(std::size_t bytes, std::size_t alignment); | ||
}} | }} | ||
Allocates memory using the {{tt|allocate}} member function of the wrapped allocator. | Allocates memory using the {{tt|allocate}} member function of the wrapped allocator. | ||
}} | }} | ||
| − | {{member|{{small| | + | {{member|{{small|''resource-adaptor-imp''::}}do_deallocate |
| | | | ||
| − | {{ddcl | since=libfund_ts | | + | {{ddcl | since=libfund_ts | |
| − | + | protected: | |
| + | virtual void do_deallocate(void *p, std::size_t bytes, std::size_t alignment); | ||
}} | }} | ||
| − | Deallocates the storage pointed to by {{tt|p}} using the {{tt|deallocate}} member function of the wrapped allocator. {{tt|p}} must have been allocated using the {{tt|allocate}} member function of an allocator that compares equal to the wrapped allocator, and must not have been subsequently deallocated. | + | Deallocates the storage pointed to by {{tt|p}} using the {{tt|deallocate}} member function of the wrapped allocator. |
| + | |||
| + | {{tt|p}} must have been allocated using the {{tt|allocate}} member function of an allocator that compares equal to the wrapped allocator, and must not have been subsequently deallocated. | ||
}} | }} | ||
| − | {{member|{{small| | + | {{member|{{small|''resource-adaptor-imp''::}}do_is_equal |
| | | | ||
| − | {{ddcl | since=libfund_ts | | + | {{ddcl | since=libfund_ts | |
| − | + | protected: | |
| + | virtual bool do_is_equal(const memory_resource& other) const noexcept; | ||
}} | }} | ||
| − | Let {{tt|p}} be {{c|dynamic_cast<const | + | Let {{tt|p}} be {{c|dynamic_cast<const /*resource-adaptor-imp*/*>(&other)}}. If {{tt|p}} is a null pointer value, returns {{c|false}}. Otherwise, return the result of comparing the allocators wrapped by {{c|*p}} and {{c|*this}} using {{c|1=operator==}}. |
| − | + | ||
}} | }} | ||
| + | |||
| + | {{langlinks|de|es|ja|ru|zh}} | ||
Latest revision as of 18:20, 9 April 2023
| Defined in header <experimental/memory_resource>
|
||
| template< class Alloc > using resource_adaptor = /*resource-adaptor-imp*/< |
(library fundamentals TS) | |
| template< class Alloc > class /*resource-adaptor-imp*/ : public memory_resource; // for exposition only |
(library fundamentals TS) | |
The alias template resource_adaptor adapts the allocator type Alloc with a memory_resource interface. The allocator is rebound to a char value type before it is actually adapted (using the resource-adaptor-imp class template), so that adapting specializations of the same allocator template always yields the same type, regardless of the value type the allocator template is originally instantiated with.
|
|
(library fundamentals TS) (until library fundamentals TS v3) |
|
|
(library fundamentals TS v3) |
resource-adaptor-imp is a class template whose members are described below. The name resource-adaptor-imp is for exposition purposes only and not normative.
In addition to meeting the Allocator requirements, Alloc must additionally satisfy the following requirements:
- std::allocator_traits<Alloc>::pointer shall be identical to Alloc::value_type*.
- std::allocator_traits<Alloc>::const_pointer shall be identical to Alloc::value_type const*.
- std::allocator_traits<Alloc>::void_pointer shall be identical to void*.
- std::allocator_traits<Alloc>::const_const_pointer shall be identical to void const*.
[edit] Member types of resource-adaptor-imp
| Member type | Definition |
allocator_type
|
Alloc
|
[edit] Member functions of resource-adaptor-imp
resource-adaptor-imp::resource-adaptor-imp
| /*resource-adaptor-imp*/() = default; |
(1) | (library fundamentals TS) |
| /*resource-adaptor-imp*/(const /*resource-adaptor-imp*/& other) = default; |
(2) | (library fundamentals TS) |
| /*resource-adaptor-imp*/(/*resource-adaptor-imp*/&& other) = default; |
(3) | (library fundamentals TS) |
| explicit /*resource-adaptor-imp*/(const Alloc& a2); |
(4) | (library fundamentals TS) |
| explicit /*resource-adaptor-imp*/(Alloc&& a2); |
(5) | (library fundamentals TS) |
1) Default constructor. Default constructs the wrapped allocator.
2) Copy constructor. Copy constructs the wrapped allocator from the allocator wrapped by
other.3) Move constructor. Move constructs the wrapped allocator from the allocator wrapped by
other.4) Initializes the wrapped allocator with
a2.5) Initializes the wrapped allocator with std::move(a2).
Parameters
| other | - | another resource-adaptor-imp object to copy or move from
|
| a2 | - | another Alloc object to copy or move from
|
resource-adaptor-imp::get_allocator
| allocator_type get_allocator() const; |
(library fundamentals TS) | |
Returns a copy of the wrapped allocator.
resource-adaptor-imp::operator=
| /*resource-adaptor-imp*/& operator=(const /*resource-adaptor-imp*/& other) = default; |
(library fundamentals TS) | |
Defaulted copy assignment operator. Copy assigns the wrapped allocator from that of other.
resource-adaptor-imp::do_allocate
| protected: virtual void* do_allocate(std::size_t bytes, std::size_t alignment); |
(library fundamentals TS) | |
Allocates memory using the allocate member function of the wrapped allocator.
resource-adaptor-imp::do_deallocate
| protected: virtual void do_deallocate(void *p, std::size_t bytes, std::size_t alignment); |
(library fundamentals TS) | |
Deallocates the storage pointed to by p using the deallocate member function of the wrapped allocator.
p must have been allocated using the allocate member function of an allocator that compares equal to the wrapped allocator, and must not have been subsequently deallocated.
resource-adaptor-imp::do_is_equal
| protected: virtual bool do_is_equal(const memory_resource& other) const noexcept; |
(library fundamentals TS) | |
Let p be dynamic_cast<const /*resource-adaptor-imp*/*>(&other). If p is a null pointer value, returns false. Otherwise, return the result of comparing the allocators wrapped by *p and *this using operator==.
