[#BloombergLP-bslma-BufferAllocator]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bslma.adoc[bslma]::BufferAllocator
:relfileprefix: ../../
:mrdocs:

Concrete buffer allocator that allocates from a user‐supplied fixed‐size buffer.

== Synopsis

Declared in `<bslma_bufferallocator.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
class BufferAllocator
    : public xref:BloombergLP/bslma/Allocator.adoc[Allocator]
----

== Description

This `class` provides a concrete buffer allocator that implements the `Allocator` interface, and allocates memory blocks from a fixed‐size buffer that is supplied by the user at construction. The allocator can supply memory that can be maximally (default) or naturally aligned.

== Base Classes

[cols="1,4"]
|===
| Name| Description
| `xref:BloombergLP/bslma/Allocator.adoc[Allocator]`
| Pure abstract protocol for clients and suppliers of raw memory.
|===

== Type Aliases

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bslma/BufferAllocator/AllocCallback.adoc[`AllocCallback`] 
| `AllocCallback` is an alias for (the address of) a function that takes an integer argument and returns `void *`.
| xref:BloombergLP/bslma/Allocator/size_type.adoc[`size_type`] 
| Alias for an unsigned integral type capable of representing the number of bytes in this platform's virtual address space.
|===


== Enums

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bslma/BufferAllocator/AlignmentStrategy.adoc[`AlignmentStrategy`] 
| Types of alignment strategy to allocate memory.
|===


== Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bslma/BufferAllocator/2constructor-0fb.adoc[`BufferAllocator`]         [.small]#[constructor]#
| Constructors
| xref:BloombergLP/bslma/BufferAllocator/2destructor.adoc[`~BufferAllocator`] [.small]#[destructor]# [.small]#[virtual]#
| Destroy this buffer allocator.
| xref:BloombergLP/bslma/Allocator/operator_assign.adoc[`operator=`] 
| 
| xref:BloombergLP/bslma/BufferAllocator/allocate-05.adoc[`allocate`] 
| Return a newly allocated block of memory of the specified `size`.
| xref:BloombergLP/bslma/BufferAllocator/deallocate-06.adoc[`deallocate`] 
| This function has no effect for this buffer allocator.
| xref:BloombergLP/bslma/Allocator/deleteObject-09.adoc[`deleteObject`] 
| `deleteObject` overloads
| xref:BloombergLP/bslma/Allocator/deleteObjectRaw-06f.adoc[`deleteObjectRaw`] 
| `deleteObjectRaw` overloads
| xref:BloombergLP/bslma/Allocator/is_equal.adoc[`is_equal`] 
| 
| xref:BloombergLP/bslma/BufferAllocator/print.adoc[`print`] 
| Write formatted debugging information to `stdout` describing the internal state of this buffer allocator.
|===


== Static Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bslma/BufferAllocator/allocateFromBuffer-0a.adoc[`allocateFromBuffer`] 
| `allocateFromBuffer` overloads
| xref:BloombergLP/bslma/Allocator/throwBadAlloc.adoc[`throwBadAlloc`] 
| Throw `std::bad_alloc` or abort the program.
|===


== Protected Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bslma/Allocator/do_allocate.adoc[`do_allocate`]  [.small]#[virtual]#
| Return a newly allocated block of at least `bytes` with `alignment`.
| xref:BloombergLP/bslma/Allocator/do_deallocate.adoc[`do_deallocate`]  [.small]#[virtual]#
| Return the memory block at `p` having `bytes` and `alignment`.
| xref:BloombergLP/bslma/Allocator/do_is_equal.adoc[`do_is_equal`]  [.small]#[virtual]#
| Return whether this allocator can exchange memory with `other`.
|===



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