This allocator acts as an aggregate that can fall back to other allocators on failure. More...
#include <fallback_allocator.hpp>
Public Member Functions | |
| fallback_allocator (AllocatorStorages...storages) noexcept | |
| Constructs each allocator in the fallback_allocator in-place, constructing each allocator from a single argument. More... | |
| fallback_allocator (fallback_allocator &&other)=default | |
| Move-constructs the fallback_allocator from an existing one. More... | |
| fallback_allocator (const fallback_allocator &other)=default | |
| Copy-constructs the fallback_allocator from an existing one. More... | |
| fallback_allocator & | operator= (fallback_allocator &&other)=default |
| Move-assigns the fallback_allocator from an existing one. More... | |
| fallback_allocator & | operator= (const fallback_allocator &other)=default |
| Copy-assigns the fallback_allocator from an existing one. More... | |
| owner< void * > | try_allocate (std::size_t size, std::size_t align) noexcept |
| Attempts to allocate memory, starting with the first allocator in sequence, and falling back to further allocators on failure. More... | |
| void | deallocate (owner< void *> p, std::size_t size) |
Deallocates the pointer p of size size from the underlying allocator. More... | |
| bool | owns (const void *p) const noexcept |
Checks if any of the allocators in the fallback allocator owns the memory pointer to by p. More... | |
| std::size_t | max_size () const noexcept |
| Determines the maximum size of the allocations that this fallback_allocator supports. More... | |
| std::size_t | min_size () const noexcept |
| Determines the minimum size of the allocations that this fallback_allocator supports. More... | |
Detailed Description
template<typename... AllocatorStorages>
class bit::memory::fallback_allocator< AllocatorStorages >
This allocator acts as an aggregate that can fall back to other allocators on failure.
This will attempt to allocate memory from the first allocator in the sequence, and – on failure – will fall-back to the next one in sequence.
For deallocations, all allocators except the last one must implement the 'owns' member function to identify ownership of previously allocated memory. The last allocator in the sequence is a special-case that doesn't require ownership, allowing for raw allocators to be used as the final fallback in the allocation sequence.
- Satisfies
- Allocator
- Template Parameters
-
AllocatorStorages the allocator storages to sequence through
Definition at line 73 of file fallback_allocator.hpp.
Constructor & Destructor Documentation
◆ fallback_allocator() [1/3]
|
explicitnoexcept |
Constructs each allocator in the fallback_allocator in-place, constructing each allocator from a single argument.
- Parameters
-
storages the allocator storage types to use
◆ fallback_allocator() [2/3]
|
default |
Move-constructs the fallback_allocator from an existing one.
- Note
- This constructor is only enabled if all allocators are move- constructible
- Parameters
-
other the other fallback_allocator to move
◆ fallback_allocator() [3/3]
|
default |
Copy-constructs the fallback_allocator from an existing one.
- Note
- This constructor is only enabled if all allocators are copy- constructible
- Parameters
-
other the other fallback_allocator to copy
Member Function Documentation
◆ deallocate()
| void bit::memory::fallback_allocator< AllocatorStorages >::deallocate | ( | owner< void *> | p, |
| std::size_t | size | ||
| ) |
Deallocates the pointer p of size size from the underlying allocator.
- Bug:
- If two allocators inside of this fallback allocator both allocate within the same memory region (e.g. inside the same memory block), then the origin of
pmay be incorrectly determined and deallocated incorrectly.
- Parameters
-
p the pointer to memory to deallocate size the size of the memory to deallocate
◆ max_size()
|
noexcept |
Determines the maximum size of the allocations that this fallback_allocator supports.
- Returns
- the max size
◆ min_size()
|
noexcept |
Determines the minimum size of the allocations that this fallback_allocator supports.
- Returns
- the min size
◆ operator=() [1/2]
|
default |
Move-assigns the fallback_allocator from an existing one.
- Note
- This operator is only enabled if all allocators are copy- assignable
- Parameters
-
other the other fallback_allocator to move
◆ operator=() [2/2]
|
default |
Copy-assigns the fallback_allocator from an existing one.
- Note
- This operator is only enabled if all allocators are copy- assignable
- Parameters
-
other the other fallback_allocator to copy
◆ owns()
|
noexcept |
Checks if any of the allocators in the fallback allocator owns the memory pointer to by p.
- Parameters
-
p the pointer to check
- Returns
trueif the memory is owned by an allocator in this allocator
◆ try_allocate()
|
noexcept |
Attempts to allocate memory, starting with the first allocator in sequence, and falling back to further allocators on failure.
- Parameters
-
size the size of the allocation request align the alignment of the allocation request
- Returns
- a pointer on success,
nullptron failure
The documentation for this class was generated from the following file:
