iteration_allocator< N, BlockOrRawAllocator > Class Template Reference

Detailed Description

template<std::size_t N, class BlockOrRawAllocator = default_allocator>
class foonathan::memory::iteration_allocator< N, BlockOrRawAllocator >

A stateful RawAllocator that is designed for allocations in a loop.

It uses N stacks for the allocation, one of them is always active. Allocation uses the currently active stack. Calling next_iteration() at the end of the loop, will make the next stack active for allocation, effectively releasing all of its memory. Any memory allocated will thus be usable for N iterations of the loop. This type of allocator is a generalization of the double frame allocator.

Typedefs
using	allocator_type

Static Functions
static std::size_t	max_iterations () noexcept

Member Functions
template<typename... Args>
	iteration_allocator (std::size_t block_size, Args &&... args)
	iteration_allocator (iteration_allocator &&other) noexcept
iteration_allocator &	operator= (iteration_allocator &&other) noexcept
void *	allocate (std::size_t size, std::size_t alignment)
void *	try_allocate (std::size_t size, std::size_t alignment) noexcept
void	next_iteration () noexcept
std::size_t	cur_iteration () const noexcept
allocator_type &	get_allocator () noexcept
std::size_t	capacity_left (std::size_t i) const noexcept
std::size_t	capacity_left () const noexcept

Constructors

iteration_allocator()

template<std::size_t N, class BlockOrRawAllocator = default_allocator>

template<typename... Args>

iteration_allocator ( std::size_t block_size, Args &&... args )

explicit

Effects:

Creates it with a given initial block size and and other constructor arguments for the BlockAllocator. It will allocate the first (and only) block and evenly divide it on all the stacks it uses.

Member Functions

allocate()

template<std::size_t N, class BlockOrRawAllocator = default_allocator>

void * allocate	(	std::size_t	size,
		std::size_t	alignment )

Effects:

Allocates a memory block of given size and alignment. It simply moves the top marker of the currently active stack.

Returns:

A node with given size and alignment.

Throws:

out_of_fixed_memory if the current stack does not have any memory left.

Requires:

size and alignment must be valid.

try_allocate()

template<std::size_t N, class BlockOrRawAllocator = default_allocator>

void * try_allocate ( std::size_t size, std::size_t alignment )

noexcept

Effects:

Allocates a memory block of given size and alignment similar to allocate().

Returns:

A node with given size and alignment or nullptr if the current stack does not have any memory left.

next_iteration()

template<std::size_t N, class BlockOrRawAllocator = default_allocator>

void next_iteration ( )

noexcept

Effects:

Goes to the next internal stack. This will clear the stack whose max_iterations() lifetime has reached, and use it for all allocations in this iteration.

Note

This function should be called at the end of the loop.

max_iterations()

template<std::size_t N, class BlockOrRawAllocator = default_allocator>

static std::size_t max_iterations ( )

staticnoexcept

Returns:

The number of iteration each allocation will live. This is the template parameter N.

cur_iteration()

template<std::size_t N, class BlockOrRawAllocator = default_allocator>

std::size_t cur_iteration ( ) const

noexcept

Returns:

The index of the current iteration. This is modulo max_iterations().

get_allocator()

template<std::size_t N, class BlockOrRawAllocator = default_allocator>

allocator_type & get_allocator ( )

noexcept

Returns:

A reference to the BlockAllocator used for managing the memory.

Requires:

It is undefined behavior to move this allocator out into another object.

capacity_left() [1/2]

template<std::size_t N, class BlockOrRawAllocator = default_allocator>

std::size_t capacity_left ( std::size_t i ) const

noexcept

Returns:

The amount of memory remaining in the stack with the given index. This is the number of bytes that are available for allocation.

capacity_left() [2/2]

template<std::size_t N, class BlockOrRawAllocator = default_allocator>

std::size_t capacity_left ( ) const

noexcept

Returns:

The amount of memory remaining in the currently active stack.