Struct CpuStorageBytes 

pub struct CpuStorageBytes { /* private fields */ }

CPU storage holding bytes addressable by Rust pointer.

Cloning is cheap — bumps the inner Arc’s refcount without copying bytes. Mutating through bytes_mut / as_slice_mut performs copy-on-write: if the Arc is uniquely held, the bytes are mutated in place; if shared, the bytes clone before mutation so other holders see the unchanged data.

Implementations

impl CpuStorageBytes

pub fn from_zero_bytes(len_bytes: usize) -> Self

Allocate len_bytes zero-initialized bytes, 64-byte aligned.

pub fn alloc(byte_count: usize) -> Self

Phase 7.5 A4 substrate alloc. Allocates byte_count zero- initialized bytes, 64-byte aligned. Synonym for Self::from_zero_bytes; named alloc for symmetry with the GPU backend allocators.

pub fn from_bytes(src: &[u8]) -> Self

Allocate a fresh aligned buffer and copy src into it.

pub fn from_slice<T: Pod>(data: &[T]) -> Self

Allocate a fresh aligned buffer and copy a typed slice into it. T must be Pod (Copy + Zeroable + ’static + no padding); covers every standard ML dtype.

pub fn len_bytes(&self) -> usize

Total byte count.

pub fn align(&self) -> usize

Alignment in bytes (always CPU_ALIGN_BYTES).

pub fn bytes(&self) -> &[u8]

Borrow the raw bytes immutably.

pub fn as_slice<T: Pod>(&self) -> Result<&[T]>

Borrow the bytes as a typed slice. Returns Err if the byte length isn’t a multiple of T’s size or the buffer alignment can’t satisfy T’s alignment requirement.

Production-correct: no panic. The 64-byte allocation alignment is sufficient for every Pod type up to and including u64/f64, so the alignment-check failure path is unreachable for standard dtypes — but we still surface it as Result for unusual Pod types (e.g., [u8; 128]).

pub fn bytes_mut(&mut self) -> &mut [u8]

Copy-on-write mutable byte access. If this storage is the sole holder of its Arc, returns a &mut [u8] into the existing buffer. If the Arc is shared, clones the bytes into a fresh Arc first so other holders are unaffected.

Centralized CoW boundary: every mutating call site goes through here, so callers don’t need to remember to clone manually. Cost when Arc is unique: one atomic load (no copy). Cost when shared: one allocation + one memcpy.

pub fn as_slice_mut<T: Pod>(&mut self) -> Result<&mut [T]>

Copy-on-write typed mutable view. Same CoW semantics as bytes_mut; returns Err on a bytemuck cast failure.

pub fn is_uniquely_owned(&self) -> bool

Whether this storage’s bytes are uniquely owned (no other CpuStorageBytes shares the same Arc). Useful for tests and for reasoning about CoW behavior.

Trait Implementations

impl BackendStorage for CpuStorageBytes

fn len_bytes(&self) -> usize

Total addressable byte count, regardless of dtype.

impl Clone for CpuStorageBytes

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for CpuStorageBytes

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

Formats the value using the given formatter.