Struct sgx_tstd::io::BorrowedBuf

pub struct BorrowedBuf<'data> { /* private fields */ }

A borrowed byte buffer which is incrementally filled and initialized.

This type is a sort of “double cursor”. It tracks three regions in the buffer: a region at the beginning of the buffer that has been logically filled with data, a region that has been initialized at some point but not yet logically filled, and a region at the end that is fully uninitialized. The filled region is guaranteed to be a subset of the initialized region.

In summary, the contents of the buffer can be visualized as:

[             capacity              ]
[ filled |         unfilled         ]
[    initialized    | uninitialized ]

A BorrowedBuf is created around some existing data (or capacity for data) via a unique reference (&mut). The BorrowedBuf can be configured (e.g., using clear or set_init), but cannot be directly written. To write into the buffer, use unfilled to create a BorrowedCursor. The cursor has write-only access to the unfilled portion of the buffer (you can think of it as a write-only iterator).

The lifetime 'data is a bound on the lifetime of the underlying data.

Implementations

impl<'data> BorrowedBuf<'data>

pub fn capacity(&self) -> usize

Returns the total capacity of the buffer.

pub fn len(&self) -> usize

Returns the length of the filled part of the buffer.

pub fn init_len(&self) -> usize

Returns the length of the initialized part of the buffer.

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

Returns a shared reference to the filled portion of the buffer.

pub fn unfilled<'this>(&'this mut self) -> BorrowedCursor<'this>

Returns a cursor over the unfilled part of the buffer.

pub fn clear(&mut self) -> &mut Self

Clears the buffer, resetting the filled region to empty.

The number of initialized bytes is not changed, and the contents of the buffer are not modified.

pub unsafe fn set_init(&mut self, n: usize) -> &mut Self

Asserts that the first n bytes of the buffer are initialized.

BorrowedBuf assumes that bytes are never de-initialized, so this method does nothing when called with fewer bytes than are already known to be initialized.

Safety

The caller must ensure that the first n unfilled bytes of the buffer have already been initialized.

Trait Implementations

impl Debug for BorrowedBuf<'_>

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

Formats the value using the given formatter.

impl<'data> From<&'data mut [MaybeUninit<u8>]> for BorrowedBuf<'data>

Create a new BorrowedBuf from an uninitialized buffer.

Use set_init if part of the buffer is known to be already initialized.

fn from(buf: &'data mut [MaybeUninit<u8>]) -> BorrowedBuf<'data>

Converts to this type from the input type.

impl<'data> From<&'data mut [u8]> for BorrowedBuf<'data>

Create a new BorrowedBuf from a fully initialized slice.

fn from(slice: &'data mut [u8]) -> BorrowedBuf<'data>

Converts to this type from the input type.