temporary_allocator Class Reference

Detailed Description

A stateful RawAllocator that handles temporary allocations.

It works similar to alloca() but uses a seperate memory_stack for the allocations, instead of the actual program stack. This avoids the stack overflow error and is portable, with a similar speed. All allocations done in the scope of the allocator object are automatically freed when the object is destroyed.

Member Functions
	temporary_allocator ()
	temporary_allocator (temporary_stack &stack)
	temporary_allocator (temporary_allocator &&)=delete
temporary_allocator &	operator= (temporary_allocator &&)=delete
void *	allocate (std::size_t size, std::size_t alignment)
bool	is_active () const noexcept
void	shrink_to_fit () noexcept
temporary_stack &	get_stack () const noexcept

Constructors

temporary_allocator() [1/2]

temporary_allocator

(

)

Effects:

Creates it by using the get_temporary_stack() to get the temporary stack.

Requires:

There must be a per-thread temporary stack (FOONATHAN_MEMORY_TEMPORARY_STACK_MODE must not be equal to 0).

temporary_allocator() [2/2]

temporary_allocator ( temporary_stack & stack )

explicit

Effects:

Creates it by giving it the temporary_stack it uses for allocation.

Member Functions

allocate()

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

Effects:

Allocates memory from the internal memory_stack by forwarding to it.

Returns:

The result of allocate().

Requires:

is_active() must return true.

is_active()

bool is_active ( ) const

noexcept

Returns:

Whether or not the allocator object is active.

Note

The active allocator object is the last object created for one stack. Moving changes the active allocator.

shrink_to_fit()

void shrink_to_fit ( )

noexcept

Effects:

Instructs it to release unnecessary memory after automatic unwinding occurs. This will effectively forward to shrink_to_fit() of the internal stack.

Note

Like the use of the temporary_stack_initializer this can be used as an optimization, to tell when the thread's temporary_stack isn't needed anymore and can be destroyed.

It doesn't call shrink to fit immediately, only in the destructor!

get_stack()

temporary_stack & get_stack ( ) const

noexcept

Returns:

The internal stack the temporary allocator is using.

Requires:

is_active() must return true.