Struct Buffer 

pub struct Buffer<const N: usize = 8>(/* private fields */);

A reusable batch of frames, filled by group::Consumer::read_frames and drained by group::Producer::write_frames.

A fixed-capacity inline buffer: N frames of stack storage, never a heap allocation and never a spill. Allocate one per task and reuse it for the life of the group rather than one per read.

N defaults to 8. Most reads are not big batches: at the live edge a frame arrives at a time, so the capacity past the first frame or two is idle stack, and a publisher holds one buffer per in-flight group. 8 costs 384 bytes and still reads ~5x faster than a frame at a time (benches/group.rs). Ask for a larger N when you know you are draining a backlog: 32 is ~8x, for 1.5 KB.

A default on a const parameter only applies in type position, so name the type to get it: let buf: frame::Buffer = Buffer::new().

A fill stamps the group’s cache access once for the whole batch, which bounds frames rather than elapsed time. A reader that may take longer than the track’s latency_max to work through one batch calls group::Consumer::keep_alive between frames, or the rest of the group is expired out from under it.

Implementations

impl<const N: usize> Buffer<N>

pub fn new() -> Self

An empty buffer with room for N frames.

pub const fn capacity(&self) -> usize

How many frames a single fill can hold.

pub fn len(&self) -> usize

How many frames the buffer currently holds.

pub fn is_empty(&self) -> bool

Whether the buffer holds no frames.

pub fn is_full(&self) -> bool

Whether the buffer is at capacity, so Self::push would refuse.

pub fn filled(&self) -> &[Frame]

The frames from the most recent fill, in order.

pub fn filled_mut(&mut self) -> &mut [Frame]

The frames from the most recent fill, mutably (to take payloads out, say).

pub fn push(&mut self, frame: Frame) -> Result<(), Frame>

Append a frame, handing it back if the buffer is already full.

Fill a buffer this way to hand a whole batch to group::Producer::write_frames.

pub fn drain(&mut self) -> impl ExactSizeIterator<Item = Frame> + '_

Move every frame out, leaving the buffer empty.

Frames left in the iterator when it drops are dropped with it, so the buffer ends up empty either way.

pub fn clear(&mut self)

Drop the current batch, leaving the buffer empty.

Trait Implementations

impl<const N: usize> Debug for Buffer<N>

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

Formats the value using the given formatter.

impl<const N: usize> Default for Buffer<N>

fn default() -> Buffer<N>

Returns the “default value” for a type.