forked from boostorg/core
114 lines
2.9 KiB
Plaintext
114 lines
2.9 KiB
Plaintext
|
[/
|
||
|
|
Copyright 2019 Glen Joseph Fernandes
|
||
|
|
(glenjofe@gmail.com)
|
||
|
|
|
||
|
|
Distributed under the Boost Software License, Version 1.0.
|
||
|
|
(http://www.boost.org/LICENSE_1_0.txt)
|
||
|
|
]
|
||
|
|
|
||
|
|
[section:default_allocator default_allocator]
|
||
|
|
|
||
|
|
[simplesect Authors]
|
||
|
|
|
||
|
|
* Glen Fernandes
|
||
|
|
|
||
|
|
[endsimplesect]
|
||
|
|
|
||
|
|
[section Overview]
|
||
|
|
|
||
|
|
The header <boost/core/default_allocator.hpp> provides the class template
|
||
|
|
`boost::default_allocator` to serve as a minimal default allocator that:
|
||
|
|
|
||
|
|
* Like C++2a's `std::allocator`, does not provide members such as `construct()`
|
||
|
|
and `destroy()` to be eligible for optimizations by allocator-aware code that
|
||
|
|
detects the absence of these members to provide more optimal construction of
|
||
|
|
objects.
|
||
|
|
* Supports `BOOST_NO_EXCEPTIONS`.
|
||
|
|
* Does not have `std` as an associated namespace.
|
||
|
|
|
||
|
|
[endsect]
|
||
|
|
|
||
|
|
[section Reference]
|
||
|
|
|
||
|
|
```
|
||
|
|
namespace boost {
|
||
|
|
|
||
|
|
template<class T>
|
||
|
|
struct default_allocator {
|
||
|
|
typedef T value_type;
|
||
|
|
typedef T* pointer;
|
||
|
|
typedef std::size_t size_type;
|
||
|
|
typedef std::ptrdiff_t difference_type;
|
||
|
|
typedef ``['true_type]`` propagate_on_container_move_assignment;
|
||
|
|
typedef ``['true_type]`` is_always_equal;
|
||
|
|
|
||
|
|
template<class U>
|
||
|
|
struct rebind {
|
||
|
|
typedef default_allocator<U> other;
|
||
|
|
};
|
||
|
|
|
||
|
|
constexpr default_allocator() = default;
|
||
|
|
|
||
|
|
template<class U>
|
||
|
|
constexpr default_allocator(const default_allocator<U>&) noexcept { }
|
||
|
|
|
||
|
|
constexpr std::size_t max_size() const noexcept;
|
||
|
|
T* allocate(std::size_t n);
|
||
|
|
void deallocate(T* p, std::size_t);
|
||
|
|
};
|
||
|
|
|
||
|
|
template<class T, class U>
|
||
|
|
constexpr bool operator==(const default_allocator<T>&,
|
||
|
|
const default_allocator<U>&) noexcept;
|
||
|
|
|
||
|
|
template<class T, class U>
|
||
|
|
constexpr operator!=(const default_allocator<T>&,
|
||
|
|
const default_allocator<U>&) noexcept;
|
||
|
|
|
||
|
|
} /* boost */
|
||
|
|
```
|
||
|
|
|
||
|
|
[section Members]
|
||
|
|
|
||
|
|
[variablelist
|
||
|
|
|
||
|
|
[[`constexpr std::size_t max_size() const noexcept;`]
|
||
|
|
[[variablelist
|
||
|
|
[[Returns][The largest value `N` for which the call `allocate(N)` might
|
||
|
|
succeed.]]]]]
|
||
|
|
[[`T* allocate(std::size_t n);`]
|
||
|
|
[[variablelist
|
||
|
|
[[Returns]
|
||
|
|
[A pointer to the initial element of an array of storage of size
|
||
|
|
`n * sizeof(T)`, aligned appropriately for objects of type `T`.]]
|
||
|
|
[[Remarks][The storage is obtained by calling `::operator new`.]]
|
||
|
|
[[Throws][`std::bad_alloc` if the storage cannot be obtained.]]]]]
|
||
|
|
[[`void deallocate(T* p, std::size_t n);`]
|
||
|
|
[[variablelist
|
||
|
|
[[Requires]
|
||
|
|
[`p` shall be a pointer value obtained from `allocate()`. `n` shall equal the
|
||
|
|
value passed as the first argument to the invocation of `allocate` which
|
||
|
|
returned `p`.]]
|
||
|
|
[[Effects][Deallocates the storage referenced by `p`.]]
|
||
|
|
[[Remarks][Uses `::operator delete`.]]]]]]
|
||
|
|
|
||
|
|
[endsect]
|
||
|
|
|
||
|
|
[section Operators]
|
||
|
|
|
||
|
|
[variablelist
|
||
|
|
[[`template<class T, class U> constexpr bool operator==(const
|
||
|
|
default_allocator<T>&, const default_allocator<U>&) noexcept;`]
|
||
|
|
[[variablelist
|
||
|
|
[[Returns][`true`.]]]]]
|
||
|
|
[[`template<class T, class U> constexpr bool operator!=(const
|
||
|
|
default_allocator<T>&, const default_allocator<U>&) noexcept;`]
|
||
|
|
[[variablelist
|
||
|
|
[[Returns][`false`.]]]]]]
|
||
|
|
|
||
|
|
[endsect]
|
||
|
|
|
||
|
|
[endsect]
|
||
|
|
|
||
|
|
[endsect]
|