Struct Buffer

pub struct Buffer { /* private fields */ }

Buffer is a mutable byte container that is aligned to crate::ALIGNMENT bytes, and has a padding so the size of the underlying allocation is a multiple of crate::ALIGNMENT.

The alignment is because we want it to be aligned to the cacheline. The padding is because we want it to be easily usable with SIMD instructions without checking length.

Implementations

impl Buffer

pub fn new(len: usize) -> Self

Create a new buffer. This function will allocate a padded and aligned memory chunk that is able to hold the given len number of bytes. The allocated memory will be zeroed.

Doesn’t allocate if len is zero. In this case the buffer will have a dangling pointer.

Panics

Panics if len overflows isize when padded to crate::ALIGNMENT bytes. Or if memory can’t be allocated.

pub fn as_ptr(&self) -> *const u8

Get a pointer to the underlying memory.

The underlying memory is aligned to crate::ALIGNMENT bytes and padded to crate::ALIGNMENT bytes.

pub fn as_mut_ptr(&mut self) -> *mut u8

Get a mutable pointer to the underlying memory.

The underlying memory is aligned to crate::ALIGNMENT bytes and padded to crate::ALIGNMENT bytes.

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

Get a slice to the underlying memory

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

Get a mutable slice to the underlying memory

pub fn cold_load(&mut self, src: &[u8])

Loads data from src to the underlying memory. Lenghth of self must be greater than or equal to the length of src

This might be faster than the regular memcopy, especially for large copies. Because it bypasses the CPU cache when writing if possible. This is only advantageus if the user won’t be reading the memory stored in self, for example it can be good when reading bulk data from disk but not so much if summing small/medium (fits in CPU cache) sized integer arrays and then doing other computation with them.

Panics

Panics if self.len() < src.len()

pub fn len(&self) -> usize

Length of the buffer. Keep in mind that the underlying memory is padded to crate::ALIGNMENT bytes so might be bigger than the returned value.

pub fn is_empty(&self) -> bool

Returns if length of buffer is zero

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

Create a Buffer from given slice.

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

Similar to Self::from_slice but bypasses CPU cache for writes if possible.

See Self::cold_load for tradeoffs.

pub fn into_ref(self) -> BufferRef

Convert this buffer into a reference for zero copy shared usage.

Trait Implementations

impl Clone for Buffer

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Drop for Buffer

fn drop(&mut self)

Executes the destructor for this type.

impl Send for Buffer

impl Sync for Buffer