Struct ArenaView 

pub struct ArenaView<'arena, 'buf>
where
    'buf: 'arena,
{ /* private fields */ }

A temporary view over the remaining bytes of a PrefixArena.

This is useful when code needs to fill an unknown-sized prefix of the remaining arena and then detach only the initialized portion.

Implementations

impl<'arena, 'buf> ArenaView<'arena, 'buf>

pub const fn len(&self) -> usize

Returns the number of bytes visible through this temporary view.

pub const fn is_empty(&self) -> bool

Returns true when no bytes are visible through this view.

pub const fn as_uninit_slice(&self) -> &[MaybeUninit<u8>]

Returns the remaining arena bytes as uninitialized storage.

pub const fn as_slice(&self) -> &[MaybeUninit<u8>]

Returns the remaining arena bytes as uninitialized storage.

pub const unsafe fn as_slice_unchecked(&self) -> &[u8]

Returns the remaining arena bytes as u8.

Safety

Every returned byte must be initialized before it is read as u8.

pub const fn as_uninit_slice_mut(&mut self) -> &mut [MaybeUninit<u8>]

Returns the remaining arena bytes as mutable uninitialized storage.

pub const fn as_slice_mut(&mut self) -> &mut [MaybeUninit<u8>]

Returns the remaining arena bytes as mutable uninitialized storage.

pub const unsafe fn as_slice_mut_unchecked(&mut self) -> &mut [u8]

Returns the remaining arena bytes as mutable u8.

Safety

Every returned byte must be initialized before it is read as u8.

pub fn init_with<F, E>(&mut self, f: F) -> Result<&mut [u8], E>

where F: FnOnce(&mut [u8]) -> Result<usize, E>,

Lets f initialize a prefix of the temporary view and returns that prefix.

This method does not shrink the underlying arena.

Panics

Panics if f returns a length greater than self.len().

pub fn init_prefix_with<F, E>(self, f: F) -> Result<&'buf mut [u8], E>

where F: FnOnce(&mut [u8]) -> Result<usize, E>,

Lets f initialize a prefix of the temporary view and then detaches that prefix from the underlying arena.

If f returns Err, the underlying arena remains unchanged.

Safety

f must return the length of a prefix that it actually initialized.

Panics

Panics if f returns a length greater than self.len().

pub fn take_prefix(self, n: usize) -> &'buf mut [MaybeUninit<u8>]

Removes the first n bytes from the underlying arena and returns them.

The returned slice is uninitialized storage. The caller must initialize it before reading from it.

Panics

Panics if n > self.len().

pub unsafe fn take_prefix_unchecked(self, n: usize) -> &'buf mut [u8]

where 'buf: 'arena,

Removes the first n bytes from the underlying arena and returns them as u8.

Safety

The caller must ensure both of the following:

• n <= self.len().
• Every returned byte is initialized before it is read as u8.