Struct futures_lite::io::Cursor
source · [−]pub struct Cursor<T> { /* private fields */ }
Expand description
Gives an in-memory buffer a cursor for reading and writing.
Examples
use futures_lite::io::{AsyncReadExt, AsyncSeekExt, AsyncWriteExt, Cursor, SeekFrom};
let mut bytes = b"hello".to_vec();
let mut cursor = Cursor::new(&mut bytes);
// Overwrite 'h' with 'H'.
cursor.write_all(b"H").await?;
// Move the cursor one byte forward.
cursor.seek(SeekFrom::Current(1)).await?;
// Read a byte.
let mut byte = [0];
cursor.read_exact(&mut byte).await?;
assert_eq!(&byte, b"l");
// Check the final buffer.
assert_eq!(bytes, b"Hello");
Implementations
sourceimpl<T> Cursor<T>
impl<T> Cursor<T>
sourcepub fn new(inner: T) -> Cursor<T>
pub fn new(inner: T) -> Cursor<T>
Creates a cursor for an in-memory buffer.
Cursor’s initial position is 0 even if the underlying buffer is not empty. Writing using
Cursor
will overwrite the existing contents unless the cursor is moved to the end of
the buffer using set_position()
or
[seek()
][AsyncSeekExt::seek()
].
Examples
use futures_lite::io::Cursor;
let cursor = Cursor::new(Vec::<u8>::new());
sourcepub fn get_ref(&self) -> &T
pub fn get_ref(&self) -> &T
Gets a reference to the underlying buffer.
Examples
use futures_lite::io::Cursor;
let cursor = Cursor::new(Vec::<u8>::new());
let r = cursor.get_ref();
sourcepub fn get_mut(&mut self) -> &mut T
pub fn get_mut(&mut self) -> &mut T
Gets a mutable reference to the underlying buffer.
Examples
use futures_lite::io::Cursor;
let mut cursor = Cursor::new(Vec::<u8>::new());
let r = cursor.get_mut();
sourcepub fn into_inner(self) -> T
pub fn into_inner(self) -> T
Unwraps the cursor, returning the underlying buffer.
Examples
use futures_lite::io::Cursor;
let cursor = Cursor::new(vec![1, 2, 3]);
assert_eq!(cursor.into_inner(), [1, 2, 3]);
sourcepub fn position(&self) -> u64
pub fn position(&self) -> u64
Returns the current position of this cursor.
Examples
use futures_lite::io::{AsyncSeekExt, Cursor, SeekFrom};
let mut cursor = Cursor::new(b"hello");
assert_eq!(cursor.position(), 0);
cursor.seek(SeekFrom::Start(2)).await?;
assert_eq!(cursor.position(), 2);
sourcepub fn set_position(&mut self, pos: u64)
pub fn set_position(&mut self, pos: u64)
Sets the position of this cursor.
Examples
use futures_lite::io::Cursor;
let mut cursor = Cursor::new(b"hello");
assert_eq!(cursor.position(), 0);
cursor.set_position(2);
assert_eq!(cursor.position(), 2);
Trait Implementations
sourceimpl<T> AsyncBufRead for Cursor<T> where
T: AsRef<[u8]> + Unpin,
impl<T> AsyncBufRead for Cursor<T> where
T: AsRef<[u8]> + Unpin,
sourceimpl<T> AsyncRead for Cursor<T> where
T: AsRef<[u8]> + Unpin,
impl<T> AsyncRead for Cursor<T> where
T: AsRef<[u8]> + Unpin,
sourceimpl AsyncWrite for Cursor<&mut [u8]>
impl AsyncWrite for Cursor<&mut [u8]>
sourcefn poll_write(
self: Pin<&mut Self>,
_: &mut Context<'_>,
buf: &[u8]
) -> Poll<Result<usize>>
fn poll_write(
self: Pin<&mut Self>,
_: &mut Context<'_>,
buf: &[u8]
) -> Poll<Result<usize>>
Attempt to write bytes from buf
into the object. Read more
sourcefn poll_write_vectored(
self: Pin<&mut Self>,
_: &mut Context<'_>,
bufs: &[IoSlice<'_>]
) -> Poll<Result<usize>>
fn poll_write_vectored(
self: Pin<&mut Self>,
_: &mut Context<'_>,
bufs: &[IoSlice<'_>]
) -> Poll<Result<usize>>
Attempt to write bytes from bufs
into the object using vectored
IO operations. Read more
sourceimpl AsyncWrite for Cursor<&mut Vec<u8>>
impl AsyncWrite for Cursor<&mut Vec<u8>>
sourcefn poll_write(
self: Pin<&mut Self>,
_: &mut Context<'_>,
buf: &[u8]
) -> Poll<Result<usize>>
fn poll_write(
self: Pin<&mut Self>,
_: &mut Context<'_>,
buf: &[u8]
) -> Poll<Result<usize>>
Attempt to write bytes from buf
into the object. Read more
sourcefn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>>
fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>>
Attempt to close the object. Read more
sourceimpl AsyncWrite for Cursor<Vec<u8>>
impl AsyncWrite for Cursor<Vec<u8>>
sourcefn poll_write(
self: Pin<&mut Self>,
_: &mut Context<'_>,
buf: &[u8]
) -> Poll<Result<usize>>
fn poll_write(
self: Pin<&mut Self>,
_: &mut Context<'_>,
buf: &[u8]
) -> Poll<Result<usize>>
Attempt to write bytes from buf
into the object. Read more
sourcefn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>>
fn poll_close(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<()>>
Attempt to close the object. Read more
Auto Trait Implementations
impl<T> RefUnwindSafe for Cursor<T> where
T: RefUnwindSafe,
impl<T> Send for Cursor<T> where
T: Send,
impl<T> Sync for Cursor<T> where
T: Sync,
impl<T> Unpin for Cursor<T> where
T: Unpin,
impl<T> UnwindSafe for Cursor<T> where
T: UnwindSafe,
Blanket Implementations
sourceimpl<R> AsyncBufReadExt for R where
R: AsyncBufRead + ?Sized,
impl<R> AsyncBufReadExt for R where
R: AsyncBufRead + ?Sized,
sourcefn fill_buf(&mut self) -> FillBuf<'_, Self>ⓘNotable traits for FillBuf<'a, R>impl<'a, R> Future for FillBuf<'a, R> where
R: AsyncBufRead + Unpin + ?Sized, type Output = Result<&'a [u8]>;
where
Self: Unpin,
fn fill_buf(&mut self) -> FillBuf<'_, Self>ⓘNotable traits for FillBuf<'a, R>impl<'a, R> Future for FillBuf<'a, R> where
R: AsyncBufRead + Unpin + ?Sized, type Output = Result<&'a [u8]>;
where
Self: Unpin,
R: AsyncBufRead + Unpin + ?Sized, type Output = Result<&'a [u8]>;
Returns the contents of the internal buffer, filling it with more data if empty. Read more
sourcefn read_until<'a>(
&'a mut self,
byte: u8,
buf: &'a mut Vec<u8>
) -> ReadUntilFuture<'_, Self>ⓘNotable traits for ReadUntilFuture<'_, R>impl<R: AsyncBufRead + Unpin + ?Sized> Future for ReadUntilFuture<'_, R> type Output = Result<usize>;
where
Self: Unpin,
fn read_until<'a>(
&'a mut self,
byte: u8,
buf: &'a mut Vec<u8>
) -> ReadUntilFuture<'_, Self>ⓘNotable traits for ReadUntilFuture<'_, R>impl<R: AsyncBufRead + Unpin + ?Sized> Future for ReadUntilFuture<'_, R> type Output = Result<usize>;
where
Self: Unpin,
Reads all bytes and appends them into buf
until the delimiter byte
or EOF is found. Read more
sourcefn read_line<'a>(&'a mut self, buf: &'a mut String) -> ReadLineFuture<'_, Self>ⓘNotable traits for ReadLineFuture<'_, R>impl<R: AsyncBufRead + Unpin + ?Sized> Future for ReadLineFuture<'_, R> type Output = Result<usize>;
where
Self: Unpin,
fn read_line<'a>(&'a mut self, buf: &'a mut String) -> ReadLineFuture<'_, Self>ⓘNotable traits for ReadLineFuture<'_, R>impl<R: AsyncBufRead + Unpin + ?Sized> Future for ReadLineFuture<'_, R> type Output = Result<usize>;
where
Self: Unpin,
Reads all bytes and appends them into buf
until a newline (the 0xA byte) or EOF is found. Read more
sourceimpl<R> AsyncReadExt for R where
R: AsyncRead + ?Sized,
impl<R> AsyncReadExt for R where
R: AsyncRead + ?Sized,
sourcefn read<'a>(&'a mut self, buf: &'a mut [u8]) -> ReadFuture<'a, Self>ⓘNotable traits for ReadFuture<'_, R>impl<R: AsyncRead + Unpin + ?Sized> Future for ReadFuture<'_, R> type Output = Result<usize>;
where
Self: Unpin,
fn read<'a>(&'a mut self, buf: &'a mut [u8]) -> ReadFuture<'a, Self>ⓘNotable traits for ReadFuture<'_, R>impl<R: AsyncRead + Unpin + ?Sized> Future for ReadFuture<'_, R> type Output = Result<usize>;
where
Self: Unpin,
Reads some bytes from the byte stream. Read more
sourcefn read_vectored<'a>(
&'a mut self,
bufs: &'a mut [IoSliceMut<'a>]
) -> ReadVectoredFuture<'a, Self>ⓘNotable traits for ReadVectoredFuture<'_, R>impl<R: AsyncRead + Unpin + ?Sized> Future for ReadVectoredFuture<'_, R> type Output = Result<usize>;
where
Self: Unpin,
fn read_vectored<'a>(
&'a mut self,
bufs: &'a mut [IoSliceMut<'a>]
) -> ReadVectoredFuture<'a, Self>ⓘNotable traits for ReadVectoredFuture<'_, R>impl<R: AsyncRead + Unpin + ?Sized> Future for ReadVectoredFuture<'_, R> type Output = Result<usize>;
where
Self: Unpin,
sourcefn read_to_end<'a>(
&'a mut self,
buf: &'a mut Vec<u8>
) -> ReadToEndFuture<'a, Self>ⓘNotable traits for ReadToEndFuture<'_, R>impl<R: AsyncRead + Unpin + ?Sized> Future for ReadToEndFuture<'_, R> type Output = Result<usize>;
where
Self: Unpin,
fn read_to_end<'a>(
&'a mut self,
buf: &'a mut Vec<u8>
) -> ReadToEndFuture<'a, Self>ⓘNotable traits for ReadToEndFuture<'_, R>impl<R: AsyncRead + Unpin + ?Sized> Future for ReadToEndFuture<'_, R> type Output = Result<usize>;
where
Self: Unpin,
sourcefn read_to_string<'a>(
&'a mut self,
buf: &'a mut String
) -> ReadToStringFuture<'a, Self>ⓘNotable traits for ReadToStringFuture<'_, R>impl<R: AsyncRead + Unpin + ?Sized> Future for ReadToStringFuture<'_, R> type Output = Result<usize>;
where
Self: Unpin,
fn read_to_string<'a>(
&'a mut self,
buf: &'a mut String
) -> ReadToStringFuture<'a, Self>ⓘNotable traits for ReadToStringFuture<'_, R>impl<R: AsyncRead + Unpin + ?Sized> Future for ReadToStringFuture<'_, R> type Output = Result<usize>;
where
Self: Unpin,
sourcefn read_exact<'a>(&'a mut self, buf: &'a mut [u8]) -> ReadExactFuture<'a, Self>ⓘNotable traits for ReadExactFuture<'_, R>impl<R: AsyncRead + Unpin + ?Sized> Future for ReadExactFuture<'_, R> type Output = Result<()>;
where
Self: Unpin,
fn read_exact<'a>(&'a mut self, buf: &'a mut [u8]) -> ReadExactFuture<'a, Self>ⓘNotable traits for ReadExactFuture<'_, R>impl<R: AsyncRead + Unpin + ?Sized> Future for ReadExactFuture<'_, R> type Output = Result<()>;
where
Self: Unpin,
Reads the exact number of bytes required to fill buf
. Read more
sourcefn take(self, limit: u64) -> Take<Self> where
Self: Sized,
fn take(self, limit: u64) -> Take<Self> where
Self: Sized,
Creates an adapter which will read at most limit
bytes from it. Read more
sourceimpl<S> AsyncSeekExt for S where
S: AsyncSeek + ?Sized,
impl<S> AsyncSeekExt for S where
S: AsyncSeek + ?Sized,
sourcefn seek(&mut self, pos: SeekFrom) -> SeekFuture<'_, Self>ⓘNotable traits for SeekFuture<'_, S>impl<S: AsyncSeek + Unpin + ?Sized> Future for SeekFuture<'_, S> type Output = Result<u64>;
where
Self: Unpin,
fn seek(&mut self, pos: SeekFrom) -> SeekFuture<'_, Self>ⓘNotable traits for SeekFuture<'_, S>impl<S: AsyncSeek + Unpin + ?Sized> Future for SeekFuture<'_, S> type Output = Result<u64>;
where
Self: Unpin,
Seeks to a new position in a byte stream. Read more
sourceimpl<W> AsyncWriteExt for W where
W: AsyncWrite + ?Sized,
impl<W> AsyncWriteExt for W where
W: AsyncWrite + ?Sized,
sourcefn write<'a>(&'a mut self, buf: &'a [u8]) -> WriteFuture<'a, Self>ⓘNotable traits for WriteFuture<'_, W>impl<W: AsyncWrite + Unpin + ?Sized> Future for WriteFuture<'_, W> type Output = Result<usize>;
where
Self: Unpin,
fn write<'a>(&'a mut self, buf: &'a [u8]) -> WriteFuture<'a, Self>ⓘNotable traits for WriteFuture<'_, W>impl<W: AsyncWrite + Unpin + ?Sized> Future for WriteFuture<'_, W> type Output = Result<usize>;
where
Self: Unpin,
Writes some bytes into the byte stream. Read more
sourcefn write_vectored<'a>(
&'a mut self,
bufs: &'a [IoSlice<'a>]
) -> WriteVectoredFuture<'a, Self>ⓘNotable traits for WriteVectoredFuture<'_, W>impl<W: AsyncWrite + Unpin + ?Sized> Future for WriteVectoredFuture<'_, W> type Output = Result<usize>;
where
Self: Unpin,
fn write_vectored<'a>(
&'a mut self,
bufs: &'a [IoSlice<'a>]
) -> WriteVectoredFuture<'a, Self>ⓘNotable traits for WriteVectoredFuture<'_, W>impl<W: AsyncWrite + Unpin + ?Sized> Future for WriteVectoredFuture<'_, W> type Output = Result<usize>;
where
Self: Unpin,
sourcefn write_all<'a>(&'a mut self, buf: &'a [u8]) -> WriteAllFuture<'a, Self>ⓘNotable traits for WriteAllFuture<'_, W>impl<W: AsyncWrite + Unpin + ?Sized> Future for WriteAllFuture<'_, W> type Output = Result<()>;
where
Self: Unpin,
fn write_all<'a>(&'a mut self, buf: &'a [u8]) -> WriteAllFuture<'a, Self>ⓘNotable traits for WriteAllFuture<'_, W>impl<W: AsyncWrite + Unpin + ?Sized> Future for WriteAllFuture<'_, W> type Output = Result<()>;
where
Self: Unpin,
Writes an entire buffer into the byte stream. Read more
sourcefn flush(&mut self) -> FlushFuture<'_, Self>ⓘNotable traits for FlushFuture<'_, W>impl<W: AsyncWrite + Unpin + ?Sized> Future for FlushFuture<'_, W> type Output = Result<()>;
where
Self: Unpin,
fn flush(&mut self) -> FlushFuture<'_, Self>ⓘNotable traits for FlushFuture<'_, W>impl<W: AsyncWrite + Unpin + ?Sized> Future for FlushFuture<'_, W> type Output = Result<()>;
where
Self: Unpin,
Flushes the stream to ensure that all buffered contents reach their destination. Read more
sourcefn close(&mut self) -> CloseFuture<'_, Self>ⓘNotable traits for CloseFuture<'_, W>impl<W: AsyncWrite + Unpin + ?Sized> Future for CloseFuture<'_, W> type Output = Result<()>;
where
Self: Unpin,
fn close(&mut self) -> CloseFuture<'_, Self>ⓘNotable traits for CloseFuture<'_, W>impl<W: AsyncWrite + Unpin + ?Sized> Future for CloseFuture<'_, W> type Output = Result<()>;
where
Self: Unpin,
Closes the writer. Read more
sourcefn boxed_writer<'a>(self) -> Pin<Box<dyn AsyncWrite + Send + 'a>> where
Self: Sized + Send + 'a,
fn boxed_writer<'a>(self) -> Pin<Box<dyn AsyncWrite + Send + 'a>> where
Self: Sized + Send + 'a,
Boxes the writer and changes its type to dyn AsyncWrite + Send + 'a
. Read more
sourceimpl<T> BorrowMut<T> for T where
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
sourceimpl<T> ToOwned for T where
T: Clone,
impl<T> ToOwned for T where
T: Clone,
type Owned = T
type Owned = T
The resulting type after obtaining ownership.
sourcefn clone_into(&self, target: &mut T)
fn clone_into(&self, target: &mut T)
toowned_clone_into
)Uses borrowed data to replace owned data, usually by cloning. Read more