pub struct BorrowedBuf<'data> {
    buf: &'data mut [MaybeUninit<u8>],
    filled: usize,
    init: usize,
}
🔬This is a nightly-only experimental API. (read_buf #78485)
Expand description

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.

Fields§

§buf: &'data mut [MaybeUninit<u8>]
🔬This is a nightly-only experimental API. (read_buf #78485)
§filled: usize
🔬This is a nightly-only experimental API. (read_buf #78485)
§init: usize
🔬This is a nightly-only experimental API. (read_buf #78485)

Implementations§

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impl<'data> BorrowedBuf<'data>

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pub fn capacity(&self) -> usize

🔬This is a nightly-only experimental API. (read_buf #78485)

Returns the total capacity of the buffer.

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pub fn len(&self) -> usize

🔬This is a nightly-only experimental API. (read_buf #78485)

Returns the length of the filled part of the buffer.

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pub fn init_len(&self) -> usize

🔬This is a nightly-only experimental API. (read_buf #78485)

Returns the length of the initialized part of the buffer.

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

🔬This is a nightly-only experimental API. (read_buf #78485)

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

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

🔬This is a nightly-only experimental API. (read_buf #78485)

Returns a cursor over the unfilled part of the buffer.

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pub fn clear(&mut self) -> &mut BorrowedBuf<'data>

🔬This is a nightly-only experimental API. (read_buf #78485)

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.

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pub unsafe fn set_init(&mut self, n: usize) -> &mut BorrowedBuf<'data>

🔬This is a nightly-only experimental API. (read_buf #78485)

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§

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impl Debug for BorrowedBuf<'_>

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

Formats the value using the given formatter. Read more
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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.

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

Converts to this type from the input type.
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impl<'data> From<&'data mut [u8]> for BorrowedBuf<'data>

Create a new BorrowedBuf from a fully initialized slice.

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

Converts to this type from the input type.

Auto Trait Implementations§

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impl<'data> RefUnwindSafe for BorrowedBuf<'data>

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impl<'data> Send for BorrowedBuf<'data>

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impl<'data> Sync for BorrowedBuf<'data>

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impl<'data> Unpin for BorrowedBuf<'data>

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impl<'data> !UnwindSafe for BorrowedBuf<'data>

Blanket Implementations§

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impl<T> Any for Twhere
    T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for Twhere
    T: ?Sized,

const: unstable · source§

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for Twhere
    T: ?Sized,

const: unstable · source§

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

const: unstable · source§

fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for Twhere
    U: From<T>,

const: unstable · source§

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T, U> TryFrom<U> for Twhere
    U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
const: unstable · source§

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for Twhere
    U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
const: unstable · source§

fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.