Trait allocators::Allocator [−] [src]

pub unsafe trait Allocator {
    unsafe fn allocate_raw(&self, size: usize, align: usize) -> Result<Block, Error>;
    unsafe fn reallocate_raw<'a>(&'a self, block: Block<'a>, new_size: usize) -> Result<Block<'a>, (Error, Block<'a>)>;
    unsafe fn deallocate_raw(&self, block: Block);

    fn allocate<T>(&self, val: T) -> Result<AllocBox<T, Self>, (Error, T)> where Self: Sized { ... }
    fn make_place<T>(&self) -> Result<Place<T, Self>, Error> where Self: Sized { ... }
}

A custom memory allocator.

Required Methods

unsafe fn allocate_raw(&self, size: usize, align: usize) -> Result<Block, Error>

Attempt to allocate a block of memory.

Returns either a block of memory allocated or an Error. If size is equal to 0, the block returned must be created by Block::empty()

Safety

Never use the block's pointer outside of the lifetime of the allocator. It must be deallocated with the same allocator as it was allocated with. It is undefined behavior to provide a non power-of-two align.

unsafe fn reallocate_raw<'a>(&'a self, block: Block<'a>, new_size: usize) -> Result<Block<'a>, (Error, Block<'a>)>

Reallocate a block of memory.

This either returns a new, possibly moved block with the requested size, or the old block back. The new block will have the same alignment as the old.

Safety

If given an empty block, it must return it back instead of allocating the new size, since the alignment is unknown.

If the requested size is 0, it must deallocate the old block and return an empty one.

unsafe fn deallocate_raw(&self, block: Block)

Deallocate the memory referred to by this block.

Safety

This block must have been allocated by this allocator.

Provided Methods

fn allocate<T>(&self, val: T) -> Result<AllocBox<T, Self>, (Error, T)> where Self: Sized

Attempts to allocate the value supplied to it.

Examples

use allocators::{Allocator, AllocBox};
fn alloc_array<A: Allocator>(allocator: &A) -> AllocBox<[u8; 1000], A> {
    allocator.allocate([0; 1000]).ok().unwrap()
}

fn make_place<T>(&self) -> Result<Place<T, Self>, Error> where Self: Sized

Attempts to create a place to allocate into. For the general purpose, calling allocate on the allocator is enough. However, when you know the value you are allocating is too large to be constructed on the stack, you should use in-place allocation.

Examples

#![feature(placement_in_syntax)]
use allocators::{Allocator, AllocBox};
fn alloc_array<A: Allocator>(allocator: &A) -> AllocBox<[u8; 1000], A> {
    // if 1000 bytes were enough to smash the stack, this would still work.
    in allocator.make_place().unwrap() { [0; 1000] }
}

Implementors