Struct SegmentedBuffer 

pub struct SegmentedBuffer { /* private fields */ }

A segmented buffer optimized for zero-copy operations.

This buffer holds multiple Bytes segments and provides efficient extraction without unnecessary copies. When data is requested and fits within a single segment, it can be returned with zero copies (just a refcount increment on the underlying Bytes).

Use Cases

• Protocol decoders reading frames from streaming data
• Minimizing memcpy overhead for small messages (< 8KB)
• Preserving arena-allocated buffer segments through the pipeline

Tradeoffs

• Fast path: Single-segment extraction is O(1) with no copy
• Slow path: Multi-segment extraction requires copying into contiguous buffer
• For large messages spanning many reads, the copy cost is unavoidable

Implementations

impl SegmentedBuffer

pub const fn new() -> Self

pub const fn len(&self) -> usize

pub const fn is_empty(&self) -> bool

pub fn push(&mut self, bytes: Bytes)

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

Copy the first n bytes into dst.

Returns false if fewer than n bytes are available.

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

Advance the queue by n bytes, dropping fully-consumed segments.

Panics

Panics if n > self.len.

pub fn take_bytes(&mut self, n: usize) -> Option<Bytes>

Take exactly n bytes from the front of the queue.

If the first segment contains all n bytes, this is zero-copy. If the bytes span multiple segments, this copies into a contiguous buffer.

Trait Implementations

impl Debug for SegmentedBuffer

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

Formats the value using the given formatter.

impl Default for SegmentedBuffer

fn default() -> SegmentedBuffer

Returns the “default value” for a type.