Struct MAPIUninit

pub struct MAPIUninit<'a, T>(/* private fields */)
where
    T: Sized;

Wrapper type for an allocation with either sys::MAPIAllocateBuffer or sys::MAPIAllocateMore which has not been initialized yet.

Implementations

impl<'a, T> MAPIUninit<'a, T>

pub fn new(count: usize) -> Result<Self, MAPIAllocError>

Create a new allocation with enough room for count elements of type T with a call to sys::MAPIAllocateBuffer. The buffer is freed as soon as the MAPIUninit or MAPIBuffer is dropped.

If you call MAPIUninit::chain to create any more allocations with sys::MAPIAllocateMore, their lifetimes are constrained to the lifetime of this allocation and they will all be freed together in a single call to sys::MAPIFreeBuffer.

pub fn chain<P>( &self, count: usize, ) -> Result<MAPIUninit<'a, P>, MAPIAllocError>

Create a new allocation with enough room for count elements of type P with a call to sys::MAPIAllocateMore. The result is a separate allocation that is not freed until self is dropped at the beginning of the chain.

You may call MAPIUninit::chain on the result as well, they will both share a root allocation created with MAPIUninit::new.

pub fn into<P>(self) -> Result<MAPIUninit<'a, P>, MAPIAllocError>

Convert an uninitialized allocation to another type. You can use this, for example, to perform an allocation with extra space in a &mut [u8] buffer, and then cast that to a specific type. This is useful with the CbNewXXX functions in crate::sized_types.

pub fn iter(&self) -> MAPIUninitIter<'a, T>

Get an iterator over the uninitialized elements.

pub fn uninit(&mut self) -> Result<&mut MaybeUninit<T>, MAPIAllocError>

Get an uninitialized out-parameter with enough room for a single element of type T.

pub unsafe fn assume_init(self) -> MAPIBuffer<'a, T>

Once the buffer is known to be completely filled in, convert this MAPIUninit to a fully initialized MAPIBuffer.

Safety

Like MaybeUninit, the caller must ensure that the buffer is completely initialized before calling MAPIUninit::assume_init. It is undefined behavior to leave it uninitialized once we start accessing it.