virtual_block_allocator Class Reference

Detailed Description

A BlockAllocator that reserves virtual memory and commits it part by part.

It is similar to memory_stack but does not support growing and uses virtual memory, also meant for big blocks not small allocations.

Member Functions
	virtual_block_allocator (std::size_t block_size, std::size_t no_blocks)
	~virtual_block_allocator () noexcept
memory_block	allocate_block ()
void	deallocate_block (memory_block block) noexcept
std::size_t	next_block_size () const noexcept
std::size_t	capacity_left () const noexcept
	virtual_block_allocator (virtual_block_allocator &&other) noexcept
virtual_block_allocator &	operator= (virtual_block_allocator &&other) noexcept

Constructors

virtual_block_allocator() [1/2]

virtual_block_allocator ( std::size_t  block_size, std::size_t  no_blocks  )

explicit

Effects:

Creates it giving it the block size and the total number of blocks it can allocate. It reserves enough virtual memory for block_size * no_blocks.

Requires:

block_size must be non-zero and a multiple of the virtual_memory_page_size. no_blocks must be bigger than 1.

Throws:

out_of_memory if it cannot reserve the virtual memory.

~virtual_block_allocator()

~virtual_block_allocator ( )

noexcept

Effects:

Releases the reserved virtual memory.

virtual_block_allocator() [2/2]

virtual_block_allocator ( virtual_block_allocator &&  other )

noexcept

Effects:

Moves the block allocator, it transfers ownership over the reserved area. This does not invalidate any memory blocks.

Member Functions

operator=()

virtual_block_allocator & operator= ( virtual_block_allocator &&  other )

noexcept

Effects:

Moves the block allocator, it transfers ownership over the reserved area. This does not invalidate any memory blocks.

allocate_block()

memory_block allocate_block

(

)

Effects:

Allocates a new memory block by committing the next next_block_size() number of bytes.

Returns:

The memory_block committed.

Throws:

out_of_memory if it cannot commit the memory or the capacity_left() is exhausted.

deallocate_block()

void deallocate_block ( memory_block  block )

noexcept

Effects:

Deallocates the last allocated memory block by decommitting it. This block will be returned again on the next call to allocate_block().

Requires:

block must be the current top block of the memory, this is guaranteed by memory_arena.

next_block_size()

std::size_t next_block_size ( ) const

noexcept

Returns:

The next block size, this is the block size of the constructor.

capacity_left()

std::size_t capacity_left ( ) const

noexcept

Returns:

The number of blocks that can be committed until it runs out of memory.