Trait mycelium_util::io::BufRead

pub trait BufRead: Read {
    // Required methods
    fn fill_buf(&mut self) -> Result<&[u8]>;
    fn consume(&mut self, amt: usize);

    // Provided methods
    fn read_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> Result<usize> { ... }
    fn read_line(&mut self, buf: &mut String) -> Result<usize> { ... }
    fn split(self, byte: u8) -> Split<Self> 
       where Self: Sized { ... }
    fn lines(self) -> Lines<Self> 
       where Self: Sized { ... }
}

A BufRead is a type of Reader which has an internal buffer, allowing it to perform extra ways of reading.

For example, reading line-by-line is inefficient without using a buffer, so if you want to read by line, you’ll need BufRead, which includes a read_line method as well as a lines iterator.

Required Methods

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

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

This function is a lower-level call. It needs to be paired with the consume method to function properly. When calling this method, none of the contents will be “read” in the sense that later calling read may return the same contents. As such, consume must be called with the number of bytes that are consumed from this buffer to ensure that the bytes are never returned twice.

An empty buffer returned indicates that the stream has reached EOF.

Errors

This function will return an I/O error if the underlying reader was read, but returned an error.

fn consume(&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 read.

This function is a lower-level call. It needs to be paired with the fill_buf method to function properly. This function does not perform any I/O, it simply informs this object that some amount of its buffer, returned from fill_buf, has been consumed and should no longer be returned. As such, this function may do odd things if fill_buf isn’t called before calling it.

The amt must be <= the number of bytes in the buffer returned by fill_buf.

Provided Methods

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

Available on crate feature alloc only.

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

This function will read bytes from the underlying stream until the delimiter or EOF is found. Once found, all bytes up to, and including, the delimiter (if found) will be appended to buf.

If successful, this function will return the total number of bytes read.

Errors

This function will ignore all instances of ErrorKind::Interrupted and will otherwise return any errors returned by fill_buf.

If an I/O error is encountered then all bytes read so far will be present in buf and its length will have been adjusted appropriately.

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

Available on crate feature alloc only.

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

This function will read bytes from the underlying stream until the newline delimiter (the 0xA byte) or EOF is found. Once found, all bytes up to, and including, the delimiter (if found) will be appended to buf.

If successful, this function will return the total number of bytes read.

If this function returns Ok(0), the stream has reached EOF.

Errors

This function has the same error semantics as read_until and will also return an error if the read bytes are not valid UTF-8. If an I/O error is encountered then buf may contain some bytes already read in the event that all data read so far was valid UTF-8.

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

where Self: Sized,

Available on crate feature alloc only.

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

The iterator returned from this function will return instances of io::Result<Vec<u8>>. Each vector returned will not have the delimiter byte at the end.

This function will yield errors whenever read_until would have also yielded an error.

fn lines(self) -> Lines<Self>

where Self: Sized,

Available on crate feature alloc only.

Returns an iterator over the lines of this reader.

The iterator returned from this function will yield instances of io::Result<String>. Each string returned will not have a newline byte (the 0xA byte) or CRLF (0xD, 0xA bytes) at the end.

Errors

Each line of the iterator has the same error semantics as BufRead::read_line.

Implementations on Foreign Types

impl BufRead for &[u8]

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

fn consume(&mut self, amt: usize)

impl<B: BufRead + ?Sized> BufRead for &mut B

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

fn consume(&mut self, amt: usize)

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

Available on crate feature alloc only.

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

Available on crate feature alloc only.

impl<B: BufRead + ?Sized> BufRead for Box<B>

Available on crate feature alloc only.

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

fn consume(&mut self, amt: usize)

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

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

Implementors

impl<T> BufRead for Cursor<T>

where T: AsRef<[u8]>,

impl<T: BufRead> BufRead for Take<T>

impl<T: BufRead, U: BufRead> BufRead for Chain<T, U>