Struct DiffPool 

pub struct DiffPool { /* private fields */ }

Pre-allocated 1.1MB ring buffer of WavDiff entries.

Never grows. When full, oldest entries are overwritten. At 120Hz with ~100 diffs/frame, this holds ~640 frames (~5.3 seconds) of history — well beyond the 120-frame rollback window.

Implementations

impl DiffPool

pub fn new() -> Self

Create a new pre-allocated DiffPool. All slots zeroed. Single heap allocation at boot — never grows.

pub fn push(&mut self, diff: WavDiff) -> u32

Append a diff to the ring buffer. Returns the absolute index. O(1), no allocation.

pub fn get(&self, index: u32) -> Option<&WavDiff>

Get a diff by absolute index. Returns None if index is out of range.

pub fn head(&self) -> usize

Current write head position.

pub fn count(&self) -> usize

Number of valid entries in the pool.

pub fn frame_diffs(&self, start: u32, count: u16) -> FrameDiffIter<'_>

Iterate diffs for a frame given start index and count. Handles ring buffer wrap-around.

pub fn frame_diffs_reverse( &self, start: u32, count: u16, ) -> FrameDiffReverseIter<'_>

Iterate diffs for a frame in reverse order (for rewind). Traverses from start + count - 1 back to start.