BloombergLP::bslma::BufferAllocator

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.

Synopsis

Declared in <bslma_bufferallocator.h>

class BufferAllocator
    : public Allocator

Base Classes

NameDescription
AllocatorThis protocol class provides a pure abstract interface and contract for clients and suppliers of raw memory. If the requested memory cannot be returned, the contract requires that an std::bad_alloc exception be thrown. Note that memory is guaranteed to be sufficiently aligned for any object of the requested size on the current platform, which may be less than the maximal alignment guarantee afforded by global operator new.

Type Aliases

NameDescription
AllocCallback AllocCallback is an alias for (the address of) a function that takes an integer argument and returns void *.
size_type Alias for an unsigned integral type capable of representing the number of bytes in this platform's virtual address space.

Enums

NameDescription
AlignmentStrategy Types of alignment strategy to allocate memory.

Member Functions

NameDescription
BufferAllocator [constructor]Constructors
~BufferAllocator [destructor] [virtual]Destroy this buffer allocator.
operator=
allocate Return a newly allocated block of memory of (at least) the specified positive size (in bytes). If size is 0, a null pointer is returned with no other effect. If this allocator cannot return the requested number of bytes, then it will return the result of invoking an optional callback function (supplied at construction); if no callback function was specified, throw a std::bad_alloc exception in an exception-enabled build, or else abort the program in a non-exception build. The behavior is undefined unless 0 <= size. Note that the alignment of the address returned depends on the alignment strategy (MAXIMUM_ALIGNMENT or NATURAL_ALIGNMENT) specified at construction of this buffer allocator. Also note that it is up to the callback function whether to return zero or throw an exception if this buffer allocator is unable to satisfy the request.
deallocate This function has no effect for this buffer allocator.
deleteObject deleteObject overloads
deleteObjectRaw deleteObjectRaw overloads
is_equal
print Write formatted debugging information to stdout describing the internal state of this buffer allocator.

Static Member Functions

NameDescription
allocateFromBuffer allocateFromBuffer overloads
throwBadAlloc Throw std::bad_alloc if exceptions are enabled or abort the program otherwise. Derived classes and helper functions will typically call this function when they are unable to satisfy an allocation request. This function never returns.

Protected Member Functions

NameDescription
do_allocate [virtual]Return a newly allocated block of memory of (at least) the specified positive bytes and having at least the specified alignment. Unless overriden in a derived class, the return value is this->allocate(bytes). If this allocator cannot return the requested number of bytes or cannot satisfy the alignment request, then it will throw a std::bad_alloc exception in an exception-enabled build, or else will abort the program in a non-exception build. Unless overriden in a derived class, this function will forward the allocation request to the allocate virtual function, padding bytes and adjusting the return value as necessary to ensure sufficient alignment. Note that if bytes is 0, the same non-null value will be returned every time.
do_deallocate [virtual]Return the memory block at the specified p address, having the specified bytes and specified alignment, back to this allocator. Unless overriden in a derived class, this function will forward the deallocation request to the deallocate virtual function, padding bytes and adjusting p as necessary to account for alignment values other than the natural alignment for an object of size bytes. The behavior is undefined unless address is a block allocated from this allocator object using the same bytes and alignment and not already deallocated.
do_is_equal [virtual]Return true if this allocator is equal to the specified other allocator, meaning (at least) that a memory block allocated by one can be deallocated by the other; otherwise return false. Unless overriden, this method returns this == &other.