C + + Konzepte: Allocator
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Kapselt Speicherzuweisung und-freigabe Strategie .
Original:
Encapsulates memory allocation and deallocation strategy.
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Jedes Standard-Bibliothek Komponente, müssen zuweisen oder veröffentlichen Lagerung kann von
std::string
, std::vector
, und jeder Behälter mit Ausnahme std::array
, um std::shared_ptr
und std::function
, tut dies durch eine Allocator
: ein Objekt einer Klasse Typ, der die folgenden Anforderungen erfüllt .Original:
Every standard library component that may need to allocate or release storage, from
std::string
, std::vector
, and every container except std::array
, to std::shared_ptr
and std::function
, does so through an Allocator
: an object of a class type that satisfies the following requirements.The text has been machine-translated via Google Translate.
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Einige Anforderungen sind optional: die Vorlage std::allocator_traits liefert die Standard-Implementierungen für alle optionalen Anforderungen, und alle Standard-Bibliothek Containern und anderen Allocator-aware Klassen Zugriff auf die Zuweisung durch
std::allocator_traits
, nicht direkt .Original:
Some requirements are optional: the template std::allocator_traits supplies the default implementations for all optional requirements, and all standard library containers and other allocator-aware classes access the allocator through
std::allocator_traits
, not directly.The text has been machine-translated via Google Translate.
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[Bearbeiten] Anforderungen
Gegeben
Original:
Given
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-
A
ein Allocator für TypT
Original:A
, an Allocator for typeT
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B
die gleiche Allocator für TypU
Original:B
, the same Allocator for typeU
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ptr
, ein Wert vom Typallocator_traits<A>::pointer
, durch Aufrufen allocator_traits<A>::allocate() erhaltenOriginal:ptr
, a value of typeallocator_traits<A>::pointer
, obtained by calling allocator_traits<A>::allocate()The text has been machine-translated via Google Translate.
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cptr
, ein Wert vom Typallocator_traits<A>::const_pointer
, durch Umwandlung ausptr
erhaltenOriginal:cptr
, a value of typeallocator_traits<A>::const_pointer
, obtained by conversion fromptr
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vptr
, ein Wert vom Typallocator_traits<A>::void_pointer
, durch Umwandlung ausptr
erhaltenOriginal:vptr
, a value of typeallocator_traits<A>::void_pointer
, obtained by conversion fromptr
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cvptr
, ein Wert vom Typallocator_traits<A>::const_void_pointer
, durch Umwandlung auscptr
oder ausvptr
erhaltenOriginal:cvptr
, a value of typeallocator_traits<A>::const_void_pointer
, obtained by conversion fromcptr
or fromvptr
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xptr
ein dereferencable Zeiger auf irgendeine ArtX
Original:xptr
, a dereferencable pointer to some typeX
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Expression | Requirements | Return type |
---|---|---|
A::pointer (optional) | Satisfies NullablePointer and RandomAccessIterator
|
|
A::const_pointer (optional) | A::pointer is convertible to A::const_pointer . Satisfies NullablePointer and RandomAccessIterator
|
|
A::void_pointer (optional) | A::pointer is convertible to A::void_pointer
B::void_pointer und A::void_pointer sind vom gleichen Typ. Erfüllt NullablePointer Original: The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
|
A::const_void_pointer (optional) | A::pointer , A::const_pointer , and A::void_pointer are convertible to A::const_void_pointer
B::const_void_pointer und A::const_void_pointer sind vom gleichen Typ. Erfüllt NullablePointer Original: The text has been machine-translated via Google Translate. You can help to correct and verify the translation. Click here for instructions. |
|
A::value_type | the type T
| |
A::size_type (optional) | A::size_type can represent the size of the largest object A can allocate
|
unsigned integer type |
A::difference_type (optional) | A::difference_type can represent the difference of any two pointers to the objects allocated by A
|
signed integer type |
A::template rebind<U>::other (optional [1]) | for any U , B::template rebind<T>::other is A
|
the type B
|
*ptr | T&
| |
*cptr | *cptr and *ptr identify the same object | const T&
|
ptr->m | same as (*ptr).m, if (*ptr).m is well-defined | the type of T::m
|
cptr->m | same as (*cptr).m, if (*cptr).m is well-defined | the type of T::m
|
static_cast<A::pointer>(vptr) | static_cast<A::pointer>(vptr) == ptr | A::pointer
|
static_cast<A::const_pointer>(cvptr) | static_cast<A::const_pointer>(vptr) == cptr | A::const_pointer
|
a.allocate(n) | allocates storage suitable for n objects of type T , but does not construct them. May throw exceptions.
|
A::pointer
|
a.allocate(n, cptr) (optional) | same as a.allocate(n) , but may use cptr in unspecified manner to aid locality
|
A::pointer
|
a.deallocate(ptr, n) | deallocates storage previously allocated by a call to a.allocate(n). Does not call destructors, if any objects were constructed, they must be destroyed before calling a.deallocate(). Does not throw exceptions. | (not used) |
a.max_size() (optional) | the largest value that can be passed to A::allocate()
|
A::size_type
|
a1 == a2 | returns true only if the storage allocated by the allocator a1 can be deallocated through a2 . Establishes reflexive, symmetric, and transitive relationship. Does not throw exceptions.
|
bool |
a1 != a2 | same as !(a1==a2) | bool |
A a1(a) | Copy-constructs a1 such that a1 == a. Does not throw exceptions.
|
|
A a(b) | Constructs a such that B(a)==b and A(b)==a. Does not throw exceptions.
|
|
A a1(std::move(a)) | Constructs a1 such that it equals the prior value of a . Does not throw exceptions.
|
|
A a(std::move(b)) | Constructs a such that it equals the prior value of A(b) . Does not throw exceptions.
|
|
a.construct(xptr, args) (optional) | Constructs an object of type X in previously-allocated storage at the address pointed to by xptr , using args as the constructor arguments
|
|
a.destroy(xptr) (optional) | Destructs an object of type X pointed to by xptr , but does not deallocate any storage.
|
|
a.select_on_container_copy_construction() (optional) | Provides an instance of A to be used by the container that is copy-constructed from the one that uses a currently. Usually returns either a copy of a or a default-constructed A() .
|
A
|
a.propagate_on_container_copy_assignment (optional) | true if the allocator of type A needs to be copied when the container that uses it is copy-assigned
|
std::true_type or std::false_type or derived from such |
a.propagate_on_container_move_assignment (optional) | true if the allocator of type A needs to be copied when the container that uses it is move-assigned
|
std::true_type or std::false_type or derived from such |
a.propagate_on_container_swap (optional) | true if the allocators of type A need to be swapped when two containers that use them are swapped
|
std::true_type or std::false_type or derived from such |
Notes:
Original:
Notes:
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[1] rebind ist nur optional (von std :: allocator_traits), wenn diese Zuweisung ist eine Vorlage des Formulars SomeAllocator <T, Args>, wo Args ist null oder mehr zusätzliche Template-Parameter .
Original:
[1] rebind is only optional (provided by std::allocator_traits) if this allocator is a template of the form SomeAllocator<T, Args>, where Args is zero or more additional template parameters.
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