Struct RingLayout 

pub struct RingLayout {
    pub slot_count: u32,
    pub slot_bytes: u32,
}

Memory layout of a single-writer, many-reader frame ring.

Layout (all integers little-endian):

[ ring header  ]  HEADER_LEN bytes: magic, version, slot_count, slot_bytes
[ slot 0       ]  SLOT_HEADER_LEN + slot_bytes + SLOT_TRAILER_LEN
[ slot 1       ]
  ...

Each slot is seq_begin:u64 | byte_len:u32 | _pad:u32 | <slot_bytes data> | seq_end:u64. The writer stores seq_begin, then the data and length, then seq_end; a reader loads seq_end, copies the data, then re-checks seq_begin and seq_end against the descriptor’s seq. If either differs the read was torn by a slot recycle and is discarded. Sizing slot_count above the number of concurrent consumers plus their read latency makes torn reads rare.

Fields

slot_count: u32

slot_bytes: u32

Capacity of one slot’s pixel region (the largest frame the ring holds).

Implementations

impl RingLayout

pub const MAGIC: u32 = 0x4144_5631

“ADV1” — ADOS vision ring, version 1.

pub const VERSION: u16 = 1

pub const HEADER_LEN: usize = 16

pub const SLOT_HEADER_LEN: usize = 16

seq_begin (u64) + byte_len (u32) + pad (u32).

pub const SLOT_TRAILER_LEN: usize = 8

seq_end (u64).

pub fn for_frame( slot_count: u32, width: u32, height: u32, format: FrameFormat, ) -> Self

Size a ring that holds frames up to width x height in format.

pub fn slot_stride(&self) -> usize

pub fn total_len(&self) -> usize

Total bytes the shared region must provide.

pub fn validate(&self) -> Result<(), RingError>

Validate the layout against the on-disk header’s field widths. The header stores slot_count in two bytes, so a layout above MAX_SLOT_COUNT would truncate on write and the reader’s header-derived layout would name a different slot than the writer used. Callers validate at ring-creation / engine startup so a misconfigured depth is rejected loudly rather than silently truncated.

pub fn write_header(&self, region: &mut [u8]) -> Result<(), RingError>

Write the ring header at the front of a freshly created region. Rejects a slot_count the two-byte header field cannot represent so the writer’s slot math (seq % slot_count) can never diverge from a reader that re-derives the layout from the header.

pub fn read_header(region: &[u8]) -> Option<RingLayout>

Read the layout a writer recorded in a region’s header.

Trait Implementations

impl Clone for RingLayout

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for RingLayout

impl Debug for RingLayout

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

Formats the value using the given formatter.

impl Eq for RingLayout

impl PartialEq for RingLayout

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for RingLayout