FixedBufferAllocator< T, COUNT, PARENT_ALLOCATOR, SINGLE_ALLOCATION > Class Template Reference

#include <fixedbufferallocator.h>

Inheritance diagram for FixedBufferAllocator< T, COUNT, PARENT_ALLOCATOR, SINGLE_ALLOCATION >:

Detailed Description

template<typename T, Int COUNT, typename PARENT_ALLOCATOR, Bool SINGLE_ALLOCATION = false>
class maxon::FixedBufferAllocator< T, COUNT, PARENT_ALLOCATOR, SINGLE_ALLOCATION >

Fixed allocator. A fixed allocator contains 'SIZEOF(T) * COUNT' bytes memory on stack. The first memory request (and any Resize calls) that are smaller than this size will return this static memory. All other requests will be routed to the PARENT_ALLOCATOR. The fixed allocator is not thread-safe!

Here an example for the use of a fixed allocator:

BaseArray<Char, 16, BASEARRAYFLAGS::NONE, FixedBufferAllocator<Char, 1024, DefaultAllocator>> buf;

In the example a BaseArray will use the guaranteed 1024 bytes from the stack / fixed allocator first. Only when the BaseArray grows bigger than 1024 characters more memory from the DefaultAllocator will be fetched. This is a convenient way to allow routines be flexible without (length) limits, but avoiding constant unnecessary memory allocations.

Template Parameters

T	A type for the size computation.
COUNT	Number of T-typed elements to reserve on the stack.
PARENT_ALLOCATOR	The allocator that shall be used when a request cannot be satisfied using the static memory.
SINGLE_ALLOCATION	False by default. True is used by the BaseArray as optimization.

Public Member Functions
	FixedBufferAllocator (Bool used=false)
	FixedBufferAllocator (const PARENT_ALLOCATOR &parent)
void *	Alloc (Int32 s, MAXON_SOURCE_LOCATION_DECLARATION)
void *	Alloc (Int64 s, MAXON_SOURCE_LOCATION_DECLARATION)
void *	Realloc (void *p, Int32 n, MAXON_SOURCE_LOCATION_DECLARATION)
void *	Realloc (void *p, Int64 n, MAXON_SOURCE_LOCATION_DECLARATION)
template<typename PTRTYPE >
void	Free (PTRTYPE *&p)
Bool	IsCompatibleWithDefaultAllocator (void *p) const

Static Public Member Functions
static Int	ComputeArraySize (Int currentSize, Int increment, Int minChunkSize)

Private Member Functions
	MAXON_DISALLOW_COPY_AND_ASSIGN (FixedBufferAllocator)

Private Attributes
FixedBufferMemory< SIZE, PARENT_ALLOCATOR, SINGLE_ALLOCATION==false >	_memory

Static Private Attributes
static const Int	SIZE

Constructor & Destructor Documentation

FixedBufferAllocator() [1/2]

FixedBufferAllocator ( Bool  used = false )

explicit

Default constructor.

FixedBufferAllocator() [2/2]

FixedBufferAllocator ( const PARENT_ALLOCATOR &  parent )

explicit

Copy constructor.

Member Function Documentation

ComputeArraySize()

static Int ComputeArraySize ( Int  currentSize, Int  increment, Int  minChunkSize  )

static

Computes the new size for a growing array THREADSAFE.

Parameters

[in]	currentSize	Current number of elements.
[in]	increment	Number of elements to be added (>= 1)
[in]	minChunkSize	The minimum number of elements upon array creation.

Returns

New number of elements.

Alloc() [1/2]

void* Alloc	(	Int32	s,
		MAXON_SOURCE_LOCATION_DECLARATION
	)

Allocates a memory block. The memory is not cleared, it may contain a certain byte pattern in debug mode.

Parameters

[in]	s	Block size in bytes (values < 0 will return nullptr)
[in]	allocLocation	Pass MAXON_SOURCE_LOCATION(_NAME) to add the current source line and file.

Returns

Memory block address or nullptr.

Alloc() [2/2]

void* Alloc	(	Int64	s,
		MAXON_SOURCE_LOCATION_DECLARATION
	)

Allocates a memory block. The memory is not cleared, it may contain a certain byte pattern in debug mode.

Parameters

[in]	s	Block size in bytes (values < 0 will return nullptr)
[in]	allocLocation	Pass MAXON_SOURCE_LOCATION(_NAME) to add the current source line and file.

Returns

Memory block address or nullptr.

Realloc() [1/2]

void* Realloc	(	void *	p,
		Int32	n,
		MAXON_SOURCE_LOCATION_DECLARATION
	)

Resizes a memory block. The content of the memory block is preserved up to the lesser of the new and old sizes, even if the block is moved to a new location. The additional memory is not cleared, it may contain a certain byte pattern in debug mode. In case that p is a nullptr the function behaves like Alloc. If the function fails to allocate the requested block of memory a nullptr is returned and the memory block pointed to by argument p is not deallocated (it is still valid with its contents unchanged). THREADSAFE.

Parameters

[in]	p	Current memory block (can be nullptr)
[in]	n	New block size in bytes (values < 0 will return nullptr)
[in]	allocLocation	Pass MAXON_SOURCE_LOCATION(_NAME) to add the current source line and file.

Returns

Memory block address or nullptr if resize is not possible (p is still valid in this case)

Realloc() [2/2]

void* Realloc	(	void *	p,
		Int64	n,
		MAXON_SOURCE_LOCATION_DECLARATION
	)

Resizes a memory block. The content of the memory block is preserved up to the lesser of the new and old sizes, even if the block is moved to a new location. The additional memory is not cleared, it may contain a certain byte pattern in debug mode. In case that p is a nullptr the function behaves like Alloc. If the function fails to allocate the requested block of memory a nullptr is returned and the memory block pointed to by argument p is not deallocated (it is still valid with its contents unchanged). THREADSAFE.

Parameters

[in]	p	Current memory block (can be nullptr)
[in]	n	New block size in bytes (values < 0 will return nullptr)
[in]	allocLocation	Pass MAXON_SOURCE_LOCATION(_NAME) to add the current source line and file.

Returns

Memory block address or nullptr if resize is not possible (p is still valid in this case)

Free()

void Free

(

PTRTYPE *&

p

)

Frees a memory block.

Parameters

[in,out]

p

Memory block address (can be nullptr, will be nullptr after return)

IsCompatibleWithDefaultAllocator()

Bool IsCompatibleWithDefaultAllocator

(

void *

p

)

const

Returns if a memory block allocated via this allocator can be reallocated or freed by the DefaultAllocator.

Parameters

[in]

p

Memory block address.

Returns

True if the memory block can be reallocated or freed by the DefaultAllocator.

MAXON_DISALLOW_COPY_AND_ASSIGN()

MAXON_DISALLOW_COPY_AND_ASSIGN ( FixedBufferAllocator< T, COUNT, PARENT_ALLOCATOR, SINGLE_ALLOCATION >  )

private

Member Data Documentation

SIZE

const Int SIZE

staticprivate

_memory

FixedBufferMemory<SIZE, PARENT_ALLOCATOR, SINGLE_ALLOCATION == false> _memory

private