Struct linked_list_allocator::Heap
[−]
[src]
pub struct Heap { /* fields omitted */ }
A fixed size heap backed by a linked list of free memory blocks.
Methods
impl Heap
[src]
const fn empty() -> Heap
Creates an empty heap. All allocate calls will return None
.
unsafe fn init(&mut self, heap_bottom: usize, heap_size: usize)
Initializes an empty heap
Unsafety
This function must be called at most once and must only be used on an empty heap.
unsafe fn new(heap_bottom: usize, heap_size: usize) -> Heap
Creates a new heap with the given bottom
and size
. The bottom address must be valid
and the memory in the [heap_bottom, heap_bottom + heap_size)
range must not be used for
anything else. This function is unsafe because it can cause undefined behavior if the
given address is invalid.
fn allocate_first_fit(&mut self, layout: Layout) -> Result<*mut u8, AllocErr>
Allocates a chunk of the given size with the given alignment. Returns a pointer to the
beginning of that chunk if it was successful. Else it returns None
.
This function scans the list of free memory blocks and uses the first block that is big
enough. The runtime is in O(n) where n is the number of free blocks, but it should be
reasonably fast for small allocations.
unsafe fn deallocate(&mut self, ptr: *mut u8, layout: Layout)
Frees the given allocation. ptr
must be a pointer returned
by a call to the allocate_first_fit
function with identical size and alignment. Undefined
behavior may occur for invalid arguments, thus this function is unsafe.
This function walks the list of free memory blocks and inserts the freed block at the
correct place. If the freed block is adjacent to another free block, the blocks are merged
again. This operation is in O(n)
since the list needs to be sorted by address.
fn bottom(&self) -> usize
Returns the bottom address of the heap.
fn size(&self) -> usize
Returns the size of the heap.
fn top(&self) -> usize
Return the top address of the heap
unsafe fn extend(&mut self, by: usize)
Extends the size of the heap by creating a new hole at the end
Unsafety
The new extended area must be valid
Trait Implementations
impl Alloc for Heap
[src]
unsafe fn alloc(&mut self, layout: Layout) -> Result<*mut u8, AllocErr>
🔬 This is a nightly-only experimental API. (allocator_api
)
the precise API and guarantees it provides may be tweaked slightly, especially to possibly take into account the types being stored to make room for a future tracing garbage collector
Returns a pointer meeting the size and alignment guarantees of layout
. Read more
unsafe fn dealloc(&mut self, ptr: *mut u8, layout: Layout)
🔬 This is a nightly-only experimental API. (allocator_api
)
the precise API and guarantees it provides may be tweaked slightly, especially to possibly take into account the types being stored to make room for a future tracing garbage collector
Deallocate the memory referenced by ptr
. Read more
fn oom(&mut self, AllocErr) -> !
🔬 This is a nightly-only experimental API. (allocator_api
)
the precise API and guarantees it provides may be tweaked slightly, especially to possibly take into account the types being stored to make room for a future tracing garbage collector
Allocator-specific method for signalling an out-of-memory condition. Read more
fn usable_size(&self, layout: &Layout) -> (usize, usize)
🔬 This is a nightly-only experimental API. (allocator_api
)
the precise API and guarantees it provides may be tweaked slightly, especially to possibly take into account the types being stored to make room for a future tracing garbage collector
Returns bounds on the guaranteed usable size of a successful allocation created with the specified layout
. Read more
unsafe fn realloc(
&mut self,
ptr: *mut u8,
layout: Layout,
new_layout: Layout
) -> Result<*mut u8, AllocErr>
&mut self,
ptr: *mut u8,
layout: Layout,
new_layout: Layout
) -> Result<*mut u8, AllocErr>
🔬 This is a nightly-only experimental API. (allocator_api
)
the precise API and guarantees it provides may be tweaked slightly, especially to possibly take into account the types being stored to make room for a future tracing garbage collector
Returns a pointer suitable for holding data described by new_layout
, meeting its size and alignment guarantees. To accomplish this, this may extend or shrink the allocation referenced by ptr
to fit new_layout
. Read more
unsafe fn alloc_zeroed(&mut self, layout: Layout) -> Result<*mut u8, AllocErr>
🔬 This is a nightly-only experimental API. (allocator_api
)
the precise API and guarantees it provides may be tweaked slightly, especially to possibly take into account the types being stored to make room for a future tracing garbage collector
Behaves like alloc
, but also ensures that the contents are set to zero before being returned. Read more
unsafe fn alloc_excess(&mut self, layout: Layout) -> Result<Excess, AllocErr>
🔬 This is a nightly-only experimental API. (allocator_api
)
the precise API and guarantees it provides may be tweaked slightly, especially to possibly take into account the types being stored to make room for a future tracing garbage collector
Behaves like alloc
, but also returns the whole size of the returned block. For some layout
inputs, like arrays, this may include extra storage usable for additional data. Read more
unsafe fn realloc_excess(
&mut self,
ptr: *mut u8,
layout: Layout,
new_layout: Layout
) -> Result<Excess, AllocErr>
&mut self,
ptr: *mut u8,
layout: Layout,
new_layout: Layout
) -> Result<Excess, AllocErr>
🔬 This is a nightly-only experimental API. (allocator_api
)
the precise API and guarantees it provides may be tweaked slightly, especially to possibly take into account the types being stored to make room for a future tracing garbage collector
Behaves like realloc
, but also returns the whole size of the returned block. For some layout
inputs, like arrays, this may include extra storage usable for additional data. Read more
unsafe fn grow_in_place(
&mut self,
ptr: *mut u8,
layout: Layout,
new_layout: Layout
) -> Result<(), CannotReallocInPlace>
&mut self,
ptr: *mut u8,
layout: Layout,
new_layout: Layout
) -> Result<(), CannotReallocInPlace>
🔬 This is a nightly-only experimental API. (allocator_api
)
the precise API and guarantees it provides may be tweaked slightly, especially to possibly take into account the types being stored to make room for a future tracing garbage collector
Attempts to extend the allocation referenced by ptr
to fit new_layout
. Read more
unsafe fn shrink_in_place(
&mut self,
ptr: *mut u8,
layout: Layout,
new_layout: Layout
) -> Result<(), CannotReallocInPlace>
&mut self,
ptr: *mut u8,
layout: Layout,
new_layout: Layout
) -> Result<(), CannotReallocInPlace>
🔬 This is a nightly-only experimental API. (allocator_api
)
the precise API and guarantees it provides may be tweaked slightly, especially to possibly take into account the types being stored to make room for a future tracing garbage collector
Attempts to shrink the allocation referenced by ptr
to fit new_layout
. Read more
fn alloc_one<T>(&mut self) -> Result<Unique<T>, AllocErr>
🔬 This is a nightly-only experimental API. (allocator_api
)
the precise API and guarantees it provides may be tweaked slightly, especially to possibly take into account the types being stored to make room for a future tracing garbage collector
Allocates a block suitable for holding an instance of T
. Read more
unsafe fn dealloc_one<T>(&mut self, ptr: Unique<T>)
🔬 This is a nightly-only experimental API. (allocator_api
)
the precise API and guarantees it provides may be tweaked slightly, especially to possibly take into account the types being stored to make room for a future tracing garbage collector
Deallocates a block suitable for holding an instance of T
. Read more
fn alloc_array<T>(&mut self, n: usize) -> Result<Unique<T>, AllocErr>
🔬 This is a nightly-only experimental API. (allocator_api
)
the precise API and guarantees it provides may be tweaked slightly, especially to possibly take into account the types being stored to make room for a future tracing garbage collector
Allocates a block suitable for holding n
instances of T
. Read more
unsafe fn realloc_array<T>(
&mut self,
ptr: Unique<T>,
n_old: usize,
n_new: usize
) -> Result<Unique<T>, AllocErr>
&mut self,
ptr: Unique<T>,
n_old: usize,
n_new: usize
) -> Result<Unique<T>, AllocErr>
🔬 This is a nightly-only experimental API. (allocator_api
)
the precise API and guarantees it provides may be tweaked slightly, especially to possibly take into account the types being stored to make room for a future tracing garbage collector
Reallocates a block previously suitable for holding n_old
instances of T
, returning a block suitable for holding n_new
instances of T
. Read more
unsafe fn dealloc_array<T>(
&mut self,
ptr: Unique<T>,
n: usize
) -> Result<(), AllocErr>
&mut self,
ptr: Unique<T>,
n: usize
) -> Result<(), AllocErr>
🔬 This is a nightly-only experimental API. (allocator_api
)
the precise API and guarantees it provides may be tweaked slightly, especially to possibly take into account the types being stored to make room for a future tracing garbage collector
Deallocates a block suitable for holding n
instances of T
. Read more