Struct RingBuffer 

pub struct RingBuffer<'a, T: Pod + FixedLayout> { /* private fields */ }

Fixed-capacity circular buffer overlaid on a byte slice.

• push always succeeds. When full, overwrites the oldest entry.
• Use for event journals, audit logs, price history, etc.
• O(1) push, O(1) read by logical index.

Implementations

impl<'a, T: Pod + FixedLayout> RingBuffer<'a, T>

pub fn from_bytes(data: &'a mut [u8]) -> Result<Self, ProgramError>

Overlay a RingBuffer on a mutable byte slice.

pub fn capacity(&self) -> usize

Maximum capacity (number of elements).

pub fn count(&self) -> usize

Current number of elements (may be less than capacity if not yet full).

pub fn push(&mut self, value: T) -> Result<(), ProgramError>

Push an element. If the buffer is full, overwrites the oldest entry.

pub fn get(&self, logical_index: usize) -> Result<T, ProgramError>

Read the element at logical index (0 = oldest still in buffer).

pub fn latest(&self) -> Result<T, ProgramError>

Read the most recently pushed element.

pub fn oldest(&self) -> Result<T, ProgramError>

Read the oldest element.

pub const fn required_bytes(capacity: usize) -> usize

Compute the byte size needed for a RingBuffer with the given capacity.