Struct Cursor

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

A Cursor wraps an in-memory BufList and provides it with a Seek implementation.

Cursors allow BufLists to implement Read and BufRead, allowing a BufList to be used anywhere you might use a reader or writer that does actual I/O.

The cursor may either own or borrow a BufList: both Cursor<BufList> and Cursor<&BufList> are supported.

Optional features

• tokio1: With this feature enabled, Cursor implements the tokio crate’s AsyncSeek, AsyncRead and AsyncBufRead.
• futures03: With this feature enabled, Cursor implements the futures crate’s AsyncSeek, AsyncRead and AsyncBufRead.

Implementations

impl<T: AsRef<BufList>> Cursor<T>

pub fn new(inner: T) -> Cursor<T>

Creates a new cursor wrapping the provided BufList.

Examples

use buf_list::{BufList, Cursor};

let cursor = Cursor::new(BufList::new());

pub fn into_inner(self) -> T

Consumes this cursor, returning the underlying value.

Examples

use buf_list::{BufList, Cursor};

let cursor = Cursor::new(BufList::new());

let vec = cursor.into_inner();

pub const fn get_ref(&self) -> &T

Gets a reference to the underlying value in this cursor.

Examples

use buf_list::{BufList, Cursor};

let cursor = Cursor::new(BufList::new());

let reference = cursor.get_ref();

pub const fn position(&self) -> u64

Returns the current position of this cursor.

Examples

use buf_list::{BufList, Cursor};
use std::io::prelude::*;
use std::io::SeekFrom;

let mut cursor = Cursor::new(BufList::from(&[1, 2, 3, 4, 5][..]));

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

cursor.seek(SeekFrom::Current(2)).unwrap();
assert_eq!(cursor.position(), 2);

cursor.seek(SeekFrom::Current(-1)).unwrap();
assert_eq!(cursor.position(), 1);

pub fn set_position(&mut self, pos: u64)

Sets the position of this cursor.

Examples

use buf_list::{BufList, Cursor};

let mut cursor = Cursor::new(BufList::from(&[1, 2, 3, 4, 5][..]));

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

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

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

Trait Implementations

impl<T: AsRef<BufList> + Unpin> AsyncBufRead for Cursor<T>

Available on crate feature futures03 only.

fn poll_fill_buf( self: Pin<&mut Self>, _: &mut Context<'_>, ) -> Poll<Result<&[u8]>>

Attempt to return the contents of the internal buffer, filling it with more data from the inner reader if it is empty.

fn consume(self: Pin<&mut Self>, amt: usize)

Tells this buffer that amt bytes have been consumed from the buffer, so they should no longer be returned in calls to poll_read.

impl<T: AsRef<BufList> + Unpin> AsyncBufRead for Cursor<T>

Available on crate feature tokio1 only.

fn poll_fill_buf( self: Pin<&mut Self>, _: &mut Context<'_>, ) -> Poll<Result<&[u8]>>

Attempts to return the contents of the internal buffer, filling it with more data from the inner reader if it is empty.

fn consume(self: Pin<&mut Self>, amt: usize)

Tells this buffer that amt bytes have been consumed from the buffer, so they should no longer be returned in calls to poll_read.

impl<T: AsRef<BufList> + Unpin> AsyncRead for Cursor<T>

Available on crate feature futures03 only.

fn poll_read( self: Pin<&mut Self>, _cx: &mut Context<'_>, buf: &mut [u8], ) -> Poll<Result<usize>>

Attempt to read from the AsyncRead into buf.

fn poll_read_vectored( self: Pin<&mut Self>, _: &mut Context<'_>, bufs: &mut [IoSliceMut<'_>], ) -> Poll<Result<usize>>

Attempt to read from the AsyncRead into bufs using vectored IO operations.

impl<T: AsRef<BufList> + Unpin> AsyncRead for Cursor<T>

Available on crate feature tokio1 only.

fn poll_read( self: Pin<&mut Self>, _: &mut Context<'_>, buf: &mut ReadBuf<'_>, ) -> Poll<Result<()>>

Attempts to read from the AsyncRead into buf.

impl<T: AsRef<BufList> + Unpin> AsyncSeek for Cursor<T>

Available on crate feature futures03 only.

fn poll_seek( self: Pin<&mut Self>, _: &mut Context<'_>, pos: SeekFrom, ) -> Poll<Result<u64>>

Attempt to seek to an offset, in bytes, in a stream.

impl<T: AsRef<BufList> + Unpin> AsyncSeek for Cursor<T>

Available on crate feature tokio1 only.

fn start_seek(self: Pin<&mut Self>, pos: SeekFrom) -> Result<()>

Attempts to seek to an offset, in bytes, in a stream.

fn poll_complete(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Result<u64>>

Waits for a seek operation to complete.

impl<T: AsRef<BufList>> BufRead for Cursor<T>

fn fill_buf(&mut self) -> Result<&[u8]>

Returns the contents of the internal buffer, filling it with more data, via Read methods, if empty.

fn consume(&mut self, amt: usize)

Marks the given amount of additional bytes from the internal buffer as having been read. Subsequent calls to read only return bytes that have not been marked as read.

fn has_data_left(&mut self) -> Result<bool, Error>

🔬This is a nightly-only experimental API. (buf_read_has_data_left)

Checks if there is any data left to be read.

fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> Result<usize, Error>

Reads all bytes into buf until the delimiter byte or EOF is reached.

fn skip_until(&mut self, byte: u8) -> Result<usize, Error>

Skips all bytes until the delimiter byte or EOF is reached.

fn read_line(&mut self, buf: &mut String) -> Result<usize, Error>

Reads all bytes until a newline (the 0xA byte) is reached, and append them to the provided String buffer.

fn split(self, byte: u8) -> Split<Self>

where Self: Sized,

Returns an iterator over the contents of this reader split on the byte byte.

fn lines(self) -> Lines<Self>

where Self: Sized,

Returns an iterator over the lines of this reader.

impl<T> Clone for Cursor<T>

where T: Clone,

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, other: &Self)

Performs copy-assignment from source.

impl<T: AsRef<BufList>> Read for Cursor<T>

fn read(&mut self, buf: &mut [u8]) -> Result<usize>

Pull some bytes from this source into the specified buffer, returning how many bytes were read.

fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> Result<usize>

Like read, except that it reads into a slice of buffers.

fn read_exact(&mut self, buf: &mut [u8]) -> Result<()>

Reads the exact number of bytes required to fill buf.

fn is_read_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)

Determines if this Reader has an efficient read_vectored implementation.

fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize, Error>

Reads all bytes until EOF in this source, placing them into buf.

fn read_to_string(&mut self, buf: &mut String) -> Result<usize, Error>

Reads all bytes until EOF in this source, appending them to buf.

fn read_buf(&mut self, buf: BorrowedCursor<'_>) -> Result<(), Error>

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

Pull some bytes from this source into the specified buffer.

fn read_buf_exact(&mut self, cursor: BorrowedCursor<'_>) -> Result<(), Error>

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

Reads the exact number of bytes required to fill cursor.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Creates a “by reference” adaptor for this instance of Read.

fn bytes(self) -> Bytes<Self>

where Self: Sized,

Transforms this Read instance to an Iterator over its bytes.

fn chain<R>(self, next: R) -> Chain<Self, R>

where R: Read, Self: Sized,

Creates an adapter which will chain this stream with another.

fn take(self, limit: u64) -> Take<Self>

where Self: Sized,

Creates an adapter which will read at most limit bytes from it.

impl<T: AsRef<BufList>> Seek for Cursor<T>

fn seek(&mut self, style: SeekFrom) -> Result<u64>

Seek to an offset, in bytes, in a stream.

fn stream_position(&mut self) -> Result<u64>

Returns the current seek position from the start of the stream.

fn rewind(&mut self) -> Result<(), Error>

Rewind to the beginning of a stream.

fn stream_len(&mut self) -> Result<u64, Error>

🔬This is a nightly-only experimental API. (seek_stream_len)

Returns the length of this stream (in bytes).

fn seek_relative(&mut self, offset: i64) -> Result<(), Error>

Seeks relative to the current position.