[−][src]Trait omnom::BufReadExt

pub trait BufReadExt: BufRead {
    fn read_while<P>(
        &mut self, 
        buf: &mut Vec<u8>, 
        predicate: P
    ) -> Result<usize>
    where
        P: FnMut(u8) -> bool,
    { ... }

    fn fill_while<P>(
        &mut self, 
        buf: &mut Vec<u8>, 
        predicate: P
    ) -> Result<usize>
    where
        Self: Read,
        P: FnMut(u8) -> bool,
    { ... }

    fn fill_until(&mut self, byte: u8, buf: &mut Vec<u8>) -> Result<usize> { ... }

    fn fill_exact(&mut self, buf: &mut [u8]) -> Result<()> { ... }

    fn skip(&mut self, n: usize) -> Result<()> { ... }

    fn skip_while<P>(&mut self, predicate: P) -> Result<usize>
    where
        P: FnMut(u8) -> bool,
    { ... }

    fn fill_be<B: ReadBytes>(&mut self) -> Result<B>
    where
        Self: Sized,
    { ... }

    fn fill_le<B: ReadBytes>(&mut self) -> Result<B>
    where
        Self: Sized,
    { ... }

    fn fill_ne<B: ReadBytes>(&mut self) -> Result<B>
    where
        Self: Sized,
    { ... }
}

Extend BufRead with methods for streaming parsing.

Provided methods

fn read_while<P>(&mut self, buf: &mut Vec<u8>, predicate: P) -> Result<usize> where
    P: FnMut(u8) -> bool, 

Read bytes based on a predicate.

read_while takes a predicate as an argument. It will call this on each byte, and copy it to the slice if the predicate evaluates to true. Returns the amount of bytes read.

Errors

If this function encounters an error of the kind ErrorKind::Interrupted then the error is ignored and the operation will continue.

If any other read error is encountered then this function immediately returns. Any bytes which have already been read will be appended to buf.

Examples

[std::io::Cursor][Cursor] is a type that implements BufRead. In this example, we use [Cursor] to read bytes in a byte slice until we encounter a hyphen:

use std::io::{self, BufRead};
use omnom::prelude::*;

let mut cursor = io::Cursor::new(b"lorem-ipsum");
let mut buf = vec![];

let num_bytes = cursor.read_while(&mut buf, |b| b != b'-')
    .expect("reading from cursor won't fail");
assert_eq!(buf, b"lorem");

fn fill_while<P>(&mut self, buf: &mut Vec<u8>, predicate: P) -> Result<usize> where
    Self: Read,
    P: FnMut(u8) -> bool, 

Try reading based on a predicate.

read_while takes a predicate as an argument. It will call this on each byte, and copy it to the slice if the predicate evaluates to true. Returns the amount of bytes read.

Unlike read_while after consuming bytes through this method you'll have to manually call BufRead::consume.

Errors

If this function encounters an error of the kind ErrorKind::Interrupted then the error is ignored and the operation will continue.

If any other read error is encountered then this function immediately returns. Any bytes which have already been read will be appended to buf.

Examples

std::io::Cursor is a type that implements BufRead. In this example, we use Cursor to read bytes in a byte slice until we encounter a hyphen:

use std::io::{self, BufRead};
use omnom::prelude::*;

let mut cursor = io::Cursor::new(b"lorem-ipsum");
let mut buf = vec![];

let num_bytes = cursor.fill_while(&mut buf, |b| b != b'-')
    .expect("reading from cursor won't fail");
assert_eq!(buf, b"lorem");
cursor.consume(num_bytes);

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

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.

Unlike read_until after consuming bytes through this method you'll have to manually call BufRead::consume.

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 BufRead::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.

Examples

std::io::Cursor is a type that implements BufRead. In this example, we use Cursor to read all the bytes in a byte slice in hyphen delimited segments:

use std::io::{self, BufRead};
use omnom::prelude::*;

let mut cursor = io::Cursor::new(b"lorem-ipsum");
let mut buf = vec![];

// cursor is at 'l'
let num_bytes = cursor.fill_until(b'-', &mut buf)
    .expect("reading from cursor won't fail");
assert_eq!(buf, b"lorem-");
assert_eq!(num_bytes, 6);
cursor.consume(num_bytes);
buf.clear();

// cursor is at 'i'
let num_bytes = cursor.fill_until(b'-', &mut buf)
    .expect("reading from cursor won't fail");
assert_eq!(buf, b"ipsum");
assert_eq!(num_bytes, 5);
cursor.consume(num_bytes);
buf.clear();

// cursor is at EOF
let num_bytes = cursor.fill_until(b'-', &mut buf)
    .expect("reading from cursor won't fail");
assert_eq!(num_bytes, 0);
assert_eq!(buf, b"");

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

Read the exact number of bytes required to fill buf.

This function reads as many bytes as necessary to completely fill the specified buffer buf.

Unlike read_exact, after reading bytes through this method you'll have to manually call BufRead::consume.

No guarantees are provided about the contents of buf when this function is called, implementations cannot rely on any property of the contents of buf being true. It is recommended that implementations only write data to buf instead of reading its contents.

Errors

If this function encounters an error of the kind ErrorKind::Interrupted then the error is ignored and the operation will continue.

If this function encounters an "end of file" before completely filling the buffer, it returns an error of the kind ErrorKind::UnexpectedEof. The contents of buf are unspecified in this case.

If any other read error is encountered then this function immediately returns. The contents of buf are unspecified in this case.

If this function returns an error, it is unspecified how many bytes it has read, but it will never read more than would be necessary to completely fill the buffer.

Examples

Files implement Read:

use std::io::{self, BufReader};
use std::io::prelude::*;
use std::fs::File;
use omnom::prelude::*;

let mut cursor = io::Cursor::new(b"lorem-ipsum");
let mut buf = vec![0; 5];

// read exactly 5 bytes
cursor.fill_exact(&mut buf).unwrap();
assert_eq!(buf, b"lorem");
buf.clear();

// the same bytes can be read again
cursor.fill_exact(&mut buf).unwrap();
assert_eq!(buf, b"lorem");
buf.clear();
cursor.consume(5);

// after consuming bytes we read new bytes
cursor.fill_exact(&mut buf).unwrap();
assert_eq!(buf, b"-ipsu");

fn skip(&mut self, n: usize) -> Result<()>

Skip the first n bytes.

fn skip_while<P>(&mut self, predicate: P) -> Result<usize> where
    P: FnMut(u8) -> bool, 

Skip bytes while the predicate is true.

fn fill_be<B: ReadBytes>(&mut self) -> Result<B> where
    Self: Sized, 

Fill bytes as big endian.

fn fill_le<B: ReadBytes>(&mut self) -> Result<B> where
    Self: Sized, 

Fill bytes as little endian.

fn fill_ne<B: ReadBytes>(&mut self) -> Result<B> where
    Self: Sized, 

Fill bytes using native endianness.

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Implementors

impl<T: BufRead> BufReadExt for T[src]

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