Struct netstack3_core::tcp::RingBuffer

pub struct RingBuffer { /* private fields */ }

A circular buffer implementation.

A RingBuffer holds a logically contiguous ring of memory in three regions:

• readable: memory is available for reading and not for writing,
• writable: memory that is available for writing and not for reading,
• reserved: memory that was read from and is no longer available for reading or for writing.

Zero or more of these regions can be empty, and a region of memory can transition from one to another in a few different ways:

Readable memory, once read, becomes writable unless a shrink operation is in progress, in which case it becomes reserved.

Writable memory, once marked as such, becomes readable.

Reserved memory will never become readable or writable, and is non-empty only while a shrink is in progress. Once the reserved segment is large enough it will be removed to complete the shrinking.

Implementations

impl RingBuffer

pub fn new(capacity: usize) -> Self

Creates a new RingBuffer.

pub fn read_with<F>(&mut self, f: F) -> usize

where F: for<'a, 'b> FnOnce(&'b [&'a [u8]]) -> usize,

Calls f with contiguous sequences of readable bytes in the buffer and discards the amount of bytes returned by f.

Panics

Panics if the closure wants to discard more bytes than possible, i.e., the value returned by f is greater than self.len().

pub fn writable_regions(&mut self) -> impl IntoIterator<Item = &mut [u8]>

Returns the writable regions of the RingBuffer.

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

Sets the target size for the RingBuffer.

Calling this must not cause the buffer to drop any data. If the new size can be accommodated immediately, it will be applied. Otherwise the buffer will be resized opportunistically during future operatins.

Trait Implementations

impl Buffer for RingBuffer

fn limits(&self) -> BufferLimits

Returns information about the number of bytes in the buffer.

fn target_capacity(&self) -> usize

Gets the target size of the buffer, in bytes.

fn request_capacity(&mut self, size: usize)

Requests that the buffer be resized to hold the given number of bytes.

impl Clone for RingBuffer

fn clone(&self) -> RingBuffer

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for RingBuffer

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

Formats the value using the given formatter.

impl Default for RingBuffer

fn default() -> Self

Returns the “default value” for a type.

impl PartialEq for RingBuffer

fn eq(&self, other: &RingBuffer) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl ReceiveBuffer for RingBuffer

fn write_at<P: Payload>(&mut self, offset: usize, data: &P) -> usize

Writes data into the buffer at offset.

fn make_readable(&mut self, count: usize)

Marks count bytes available for the application to read.

impl SendBuffer for RingBuffer

fn mark_read(&mut self, count: usize)

Removes count bytes from the beginning of the buffer as already read.

fn peek_with<'a, F, R>(&'a mut self, offset: usize, f: F) -> R

where F: FnOnce(SendPayload<'a>) -> R,

Calls f with contiguous sequences of readable bytes in the buffer without advancing the reading pointer.

impl Eq for RingBuffer

impl StructuralPartialEq for RingBuffer