Cursor in async_std::io - Rust (original) (raw)

pub struct Cursor<T> { /* private fields */ }

Expand description

A Cursor wraps an in-memory buffer and provides it with aSeek implementation.

Cursors are used with in-memory buffers, anything implementingAsRef<[u8]>, to allow them to implement Read and/or Write, allowing these buffers to be used anywhere you might use a reader or writer that does actual I/O.

The standard library implements some I/O traits on various types which are commonly used as a buffer, like Cursor<Vec<u8>> andCursor<&[u8]>.

Source§

Source

Creates a new cursor wrapping the provided underlying in-memory buffer.

Cursor initial position is 0 even if underlying buffer (e.g., Vec) is not empty. So writing to cursor starts with overwriting Veccontent, not with appending to it.

§Examples

use async_std::io::Cursor;

let buff = Cursor::new(Vec::new());

Source

Consumes this cursor, returning the underlying value.

§Examples

use async_std::io::Cursor;

let buff = Cursor::new(Vec::new());

let vec = buff.into_inner();

Source

Gets a reference to the underlying value in this cursor.

§Examples

use async_std::io::Cursor;

let buff = Cursor::new(Vec::new());

let reference = buff.get_ref();

Source

Gets a mutable reference to the underlying value in this cursor.

Care should be taken to avoid modifying the internal I/O state of the underlying value as it may corrupt this cursor’s position.

§Examples

use async_std::io::Cursor;

let mut buff = Cursor::new(Vec::new());

let reference = buff.get_mut();

Source

Returns the current position of this cursor.

§Examples

use async_std::io::Cursor;
use async_std::io::prelude::*;
use async_std::io::SeekFrom;

let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);

assert_eq!(buff.position(), 0);

buff.seek(SeekFrom::Current(2)).await?;
assert_eq!(buff.position(), 2);

buff.seek(SeekFrom::Current(-1)).await?;
assert_eq!(buff.position(), 1);

Source

Sets the position of this cursor.

§Examples

use async_std::io::Cursor;

let mut buff = Cursor::new(vec![1, 2, 3, 4, 5]);

assert_eq!(buff.position(), 0);

buff.set_position(2);
assert_eq!(buff.position(), 2);

buff.set_position(4);
assert_eq!(buff.position(), 4);