Struct Region 

pub struct Region { /* private fields */ }

A run of pages AllocMem mapped for this task, readable and writable, owned by this value.

Neither Clone nor Copy: there is one owner, and a mutable slice can be borrowed from it only through &mut self, so no two live slices of it can alias.

Implementations

impl Region

pub fn alloc(ctx: &ServiceContext, bytes: usize) -> Result<Region, AllocError>

Ask the kernel for at least bytes of fresh memory, rounded up to whole pages.

Denied when it would pass this task’s memory limit, Failed when the machine has no frames left or bytes is zero or too large to round.

pub fn len(&self) -> usize

Its length in bytes: a whole number of pages, at least what was asked for.

pub fn is_empty(&self) -> bool

Always false: a region of no bytes cannot be made.

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

The region, to read.

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

The region, to write.

pub fn words_mut(&mut self) -> &mut [u32]

The region as 32-bit words, to write: for a device FIFO that is read a word at a time (a WiFi chip’s SDIO read buffer, larger than any stack can hold). The same memory as bytes, in the machine’s own byte order.