#include <bslma_bufferallocator.h>

Inheritance diagram for bslma::BufferAllocator:

Public Types
enum	AlignmentStrategy { MAXIMUM_ALIGNMENT, NATURAL_ALIGNMENT }
	Types of alignment strategy to allocate memory. More...
typedef void (	AllocCallback )(int)
typedef bsls::Types::size_type	size_type
Public Member Functions
	BufferAllocator (char *buffer, size_type bufSize, AllocCallback allocCallback=0)
	BufferAllocator (char *buffer, size_type bufSize, AlignmentStrategy strategy, AllocCallback allocCallback=0)
	~BufferAllocator ()
void *	allocate (size_type size)
void	deallocate (void *address)
void	print () const
template<class TYPE >
void	deleteObject (const TYPE *object)
void	deleteObject (bsl::nullptr_t)
template<class TYPE >
void	deleteObjectRaw (const TYPE *object)
void	deleteObjectRaw (bsl::nullptr_t)
Static Public Member Functions
static void *	allocateFromBuffer (int cursor, char buffer, size_type bufSize, size_type size, AlignmentStrategy strategy)
static void *	allocateFromBuffer (int cursor, char buffer, size_type bufSize, size_type size, int alignment)
static void	throwBadAlloc ()

Detailed 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.

See Component bslma_bufferallocator

Member Typedef Documentation

typedef void*(* bslma::BufferAllocator::AllocCallback)(int)

AllocCallback is an alias for (the address of) a function that takes an integer argument and returns void *.

typedef bsls::Types::size_type bslma::Allocator::size_type [inherited]

Reimplemented in bdlma::ConcurrentPoolAllocator.

Member Enumeration Documentation

enum bslma::BufferAllocator::AlignmentStrategy

Enumerator:

MAXIMUM_ALIGNMENT	Default. Return memory on maximally-aligned boundary `bsls::AlignmentUtil::BSLS_MAX_ALIGNMENT` (as required for ANSI standard allocators).
NATURAL_ALIGNMENT	Return memory aligned on a boundary that is the largest power of two dividing the requested size (up to `bsls::AlignmentUtil::BSLS_MAX_ALIGNMENT`).

Constructor & Destructor Documentation

bslma::BufferAllocator::BufferAllocator	(	char *	buffer,
		size_type	bufSize,
		AllocCallback	allocCallback = `0`
	)

Create a buffer allocator for allocating memory blocks from the specified buffer of the specified bufSize. Optionally specify a callback function allocCallback that is invoked when a call to allocate cannot be fulfilled from buffer. Note that maximum alignment is used when allocating memory.

bslma::BufferAllocator::BufferAllocator	(	char *	buffer,
		size_type	bufSize,
		AlignmentStrategy	strategy,
		AllocCallback	allocCallback = `0`
	)

Create a buffer allocator for allocating memory blocks from the specified buffer of the specified bufSize. Use the specified alignment strategy to allocate memory. Optionally specify a callback function allocCallback that is invoked when a call to allocate cannot be fulfilled from buffer.

bslma::BufferAllocator::~BufferAllocator ( )

Destroy this buffer allocator.

Member Function Documentation

static void* bslma::BufferAllocator::allocateFromBuffer	(	int *	cursor,
		char *	buffer,
		size_type	bufSize,
		size_type	size,
		AlignmentStrategy	strategy
	)			`[static]`

static void* bslma::BufferAllocator::allocateFromBuffer	(	int *	cursor,
		char *	buffer,
		size_type	bufSize,
		size_type	size,
		int	alignment
	)			`[static]`

Allocate a memory block of the specified size from the specified buffer at the specified cursor position. Return the address of the allocated memory block if buffer contains enough available memory, and null otherwise. The cursor is set to the index of the next available byte in buffer after the allocation. Use the specified alignment strategy (or alignment value) to allocate memory. If size is 0, do not allocate memory and return zero. The behavior is undefined unless 0 < = bufSize, 0 <= size, 0 < alignment <= bsls::AlignmentUtil::BSLS_MAX_ALIGNMENT, and alignment is an integral power of 2.

void* bslma::BufferAllocator::allocate ( size_type size ) [virtual]

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.

Implements bslma::Allocator.

void bslma::BufferAllocator::deallocate ( void * address ) [virtual]

This function has no effect for this buffer allocator.

Implements bslma::Allocator.

void bslma::BufferAllocator::print ( ) const

Write formatted debugging information to stdout describing the internal state of this buffer allocator.

static void bslma::Allocator::throwBadAlloc ( ) [static, inherited]

DEPRECATED: Use bsls::BslExceptionUtil::throwBadAlloc instead.

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.

template<class TYPE >

void bslma::Allocator::deleteObject ( const TYPE * object ) [inherited]

Destroy the specified object based on its dynamic type and then use this allocator to deallocate its memory footprint. Do nothing if object is a null pointer. The behavior is undefined unless object, when cast appropriately to void *, was allocated using this allocator and has not already been deallocated. Note that dynamic_cast<void *>(object) is applied if TYPE is polymorphic, and static_cast<void *>(object) is applied otherwise.

void bslma::Allocator::deleteObject ( bsl::nullptr_t ) [inherited]

This function has no effect. Note that it exists to support calling deleteObject will a null pointer literal, that would otherwise not deduce to a pointer type for the method above. As calls to deleteObject with (typed) null pointer values have well-defined behavior, it should also support calls with a null pointer literal.

template<class TYPE >

void bslma::Allocator::deleteObjectRaw ( const TYPE * object ) [inherited]

Destroy the specified object and then use this allocator to deallocate its memory footprint. Do nothing if object is a null pointer. The behavior is undefined unless object was allocated using this allocator, is not a secondary base class pointer -- i.e., the address is (numerically) the same as when it was originally dispensed by this allocator, and has not already been deallocated.

void bslma::Allocator::deleteObjectRaw ( bsl::nullptr_t ) [inherited]

This function has no effect. Note that it exists to support calling deleteObjectRaw will a null pointer literal, that would otherwise not deduce to a pointer type for the method above. As calls to deleteObjectRaw with (typed) null pointer values have well-defined behavior, it should also support calls with a null pointer literal.

The documentation for this class was generated from the following file:

bslma_bufferallocator.h

bslma::BufferAllocator Class Reference

Public Types

Public Member Functions

Static Public Member Functions

Detailed Description

Member Typedef Documentation

Member Enumeration Documentation

Constructor & Destructor Documentation

Member Function Documentation