Struct generic_vec::raw::UninitBuffer

#[repr(transparent)]pub struct UninitBuffer<T, A = u8>(_);

An uninitialized storage. This storage can store values of any type that has an alignment smaller of equal to T or A.

UninitBuffer has a max capacity of round_up(size_of::<T>(), align_::<A>()) / size_of::<Element>() elements.

i.e. UninitBuffer<[i32; 12]> can store 12 i32s, but UninitBuffer<[i32; 1], u64> can store 2 i32s. Because u64 is aligned to 8 bytes, so round_up(4 bytes, 8 bytes) / 4 bytes == 2`

You can query the capacity with UninitBuffer::capacity

assert_eq!(UninitBuffer::<[i32; 12]>::capacity::<i32>(), 12);
assert_eq!(UninitBuffer::<[i32; 1], u64>::capacity::<i32>(), 2);
assert_eq!(UninitBuffer::<[i32; 1]>::capacity::<u64>(), 0);

In memory representation

This type is represented in memory as

#[repr(C)]
struct AlignedBuffer<T, A> {
    align: [A; 0],
    value: T,
}

The size of the buffer is determined by type paramter T, and the alignment is the maximum alignment of T and A. This means that A should be used to ensure a certain alignment.

Implementations

impl<T, A> UninitBuffer<T, A>

pub const fn capacity<U>() -> usize

Get the capacity of this buffer for a given element type

pub const fn uninit() -> Self

Create a new uninitialized array storage

pub const fn new(value: T) -> Self

Create a new uninitialized array storage with the given value

Trait Implementations

impl<T, A> Clone for UninitBuffer<T, A>

pub fn clone(&self) -> Self

Returns a copy of the value.

pub fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T, A> Default for UninitBuffer<T, A>

pub fn default() -> Self

Returns the "default value" for a type.

impl<T, A> Send for UninitBuffer<T, A>

impl<U, T, A> Storage<U> for UninitBuffer<T, A>

pub const IS_ALIGNED: bool

Is the pointer from as_ptr guaranteed to be aligned to T

pub fn capacity(&self) -> usize

The number of elements that it is valid to write to this Storage

pub fn as_ptr(&self) -> *const U

Returns a pointer to the first element

pub fn as_mut_ptr(&mut self) -> *mut U

Returns a mutable pointer to the first element

pub fn reserve(&mut self, new_capacity: usize)

Reserves space for at least new_capacity elements

pub fn try_reserve(&mut self, capacity: usize) -> bool

Tries to reserve space for at least new_capacity elements

impl<U, T, A> StorageWithCapacity<U> for UninitBuffer<T, A>

pub fn with_capacity(capacity: usize) -> Self

Creates a new storage with at least the given storage capacity

impl<T, A> Sync for UninitBuffer<T, A>