Struct completion_io::ReadBuf

pub struct ReadBuf<'a> { /* fields omitted */ }

A wrapper around a byte buffer that is incrementally filled and initialized.

Implementations

impl<'a> ReadBuf<'a>

pub fn new(buf: &'a mut [u8]) -> Self

Create a new ReadBuf from a fully initialized buffer.

pub fn uninit(data: &'a mut [MaybeUninit<u8>]) -> ReadBuf<'a>

Create a new ReadBuf from a fully uninitialized buffer.

Use assume_init if part of the buffer is known to be already initialized.

pub fn as_mut(&mut self) -> ReadBufMut<'_>

Get a mutable reference to this buffer as a ReadBufMut.

#[must_use]pub fn into_all(self) -> &'a mut [MaybeUninit<u8>]

Consume the buffer, returning the entire partially initialized backing slice.

#[must_use]pub fn into_parts(
    self
) -> (&'a mut [u8], &'a mut [u8], &'a mut [MaybeUninit<u8>])

Consume the buffer, returning its three parts, the filled portion, the unfilled portion and the uninitialized portion.

#[must_use]pub fn into_filled(self) -> &'a mut [u8]

Consume the buffer, returning its filled portion.

impl ReadBuf<'_>

These methods are also present on ReadBufMut.

#[must_use]pub fn capacity(&self) -> usize

Get the total capacity of the buffer.

#[must_use]pub fn filled(&self) -> &[u8]

Get a shared reference to the filled portion of the buffer.

#[must_use]pub fn filled_mut(&mut self) -> &mut [u8]

Get a mutable reference to the filled portion of the buffer.

#[must_use]pub fn initialized(&self) -> &[u8]

Get a shared reference to the initialized portion of the buffer.

This includes the filled portion.

pub fn initialized_mut(&mut self) -> &mut [u8]

Get a mutable reference to the initialized portion of the buffer.

This includes the filled portion.

#[must_use]pub unsafe fn unfilled_mut(&mut self) -> &mut [MaybeUninit<u8>]

Get a mutable reference to the unfilled part of the buffer without ensuring that it has been fully initialized.

Safety

The caller must not deinitialize portions of the buffer that have already been initialized.

#[must_use]pub fn all(&self) -> &[MaybeUninit<u8>]

Get a shared reference to the entire backing buffer.

#[must_use]pub unsafe fn all_mut(&mut self) -> &mut [MaybeUninit<u8>]

Get a mutable reference to the entire backing buffer.

Safety

The caller must not deinitialize portions of the buffer that have already been initialized.

pub fn initialize_unfilled(&mut self) -> &mut [u8]

Get a mutable reference to the unfilled part of the buffer, ensuring it is fully

initialized.

Since ReadBuf tracks the region of the buffer that has been initialized, this is effectively "free" after the first use.

pub fn initialize_unfilled_to(&mut self, n: usize) -> &mut [u8]

Get a mutable reference to the first n bytes of the unfilled part of the buffer, ensuring it is fully initialized.

Panics

Panics if self.remaining() is less than n.

#[must_use]pub fn remaining(&self) -> usize

Get the number of bytes at the end of the slice that have not yet been filled.

pub fn clear(&mut self)

Clear the buffer, resetting the filled region to empty.

The number of initialized bytes is not changed, and the contents of the buffer is not modified.

pub fn add_filled(&mut self, n: usize)

Increase the size of the filled region of the buffer by n bytes.

The number of initialized bytes is not changed.

Panics

Panics if the filled region of the buffer would become larger than the initialized region.

pub fn set_filled(&mut self, n: usize)

Set the size of the filled region of the buffer to n.

The number of initialized bytes is not changed.

Note that this can be used to shrink the filled region of the buffer in addition to growing it (for example, by a Read implementation that compresses data in-place).

Panics

Panics if the filled region of the buffer would become larger than the initialized region.

pub unsafe fn assume_init(&mut self, n: usize)

Asserts that the first n unfilled bytes of the buffer are initialized.

ReadBuf assumes that bytes are never deinitialized, so this method does nothing when called with fewer bytes than are already known to be initialized.

Safety

The caller must ensure that the first n unfilled bytes of the buffer have already been initialized.

pub fn append(&mut self, other: &[u8])

Appends data to the buffer, advancing the written position and possibly also the initialized position.

Panics

Panics if self.remaining() is less than other.len().

Trait Implementations

impl Debug for ReadBuf<'_>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.