[−][src]Trait omnom::BufReadExt
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,
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 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,
P: FnMut(u8) -> bool,
Skip bytes while the predicate is true.
fn skip_until(&mut self, byte: u8) -> Result<usize>
Skip bytes 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 skipped.
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, Read}; use omnom::prelude::*; let mut cursor = io::Cursor::new(b"lorem-ipsum"); // skip up to and including '-' let num_bytes = cursor.skip_until(b'-').unwrap(); assert_eq!(num_bytes, 6); // read the rest of the bytes let mut buf = [0; 5]; cursor.read_exact(&mut buf).unwrap(); assert_eq!(&buf, b"ipsum");