Struct iowrap::Eof

pub struct Eof<R: Read> { /* fields omitted */ }

Track whether a stream has hit the end of file.

This allows slightly nicer code when reading lots of items using an uncooperative api, or when you want an UnexpectedEof only after the first byte.

Example

use std::io;
use std::io::Read;
use std::fs::File;
use iowrap::Eof;

fn load() -> io::Result<Vec<u64>> {
  let mut ret = Vec::new();
  let mut file = Eof::new(File::open("foo.bin")?);
  while !file.eof()? {
    ret.push(third_party::parse_thing(&mut file));
  }
  Ok(ret)
}

mod third_party {
  use std::io::Read;
  pub fn parse_thing<R: Read>(mut from: R) -> u64 {
    let mut buf = [0u8; 8];
    from.read_exact(&mut buf).unwrap();
    u64::from(buf[0]) // oops!
  }
}

Methods

impl<R: Read> Eof<R>

fn new(inner: R) -> Self

fn eof(&mut self) -> Result<bool>

Test if we are at the end of the stream. If false, then a proceeding read() will always succeed.

fn held_state(&self) -> Option<u8>

The buffered value, which we read while checking for EOF.

fn get_ref(&self) -> &R

fn get_mut(&mut self) -> &mut R

fn into_inner(self) -> R

Trait Implementations

impl<R: Read> Read for Eof<R>

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.

unsafe fn initializer(&self) -> Initializer

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

Determines if this Reader can work with buffers of uninitialized memory.

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

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

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

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

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

Read the exact number of bytes required to fill buf.

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

Creates a "by reference" adaptor for this instance of Read.

fn bytes(self) -> Bytes<Self>

Transforms this Read instance to an [Iterator] over its bytes.

fn chars(self) -> Chars<Self>

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

the semantics of a partial read/write of where errors happen is currently unclear and may change

Transforms this Read instance to an [Iterator] over [char]s.

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

Creates an adaptor which will chain this stream with another.

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

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