Function nom::multi::length_value
source · [−]pub fn length_value<I, O, N, E, F, G>(
f: F,
g: G
) -> impl FnMut(I) -> IResult<I, O, E> where
I: Clone + InputLength + InputTake,
N: ToUsize,
F: Parser<I, N, E>,
G: Parser<I, O, E>,
E: ParseError<I>,
Expand description
Gets a number from the first parser,
takes a subslice of the input of that size,
then applies the second parser on that subslice.
If the second parser returns Incomplete
,
length_value
will return an error.
Arguments
f
The parser to apply.g
The parser to apply on the subslice.
use nom::number::complete::be_u16;
use nom::multi::length_value;
use nom::bytes::complete::tag;
fn parser(s: &[u8]) -> IResult<&[u8], &[u8]> {
length_value(be_u16, tag("abc"))(s)
}
assert_eq!(parser(b"\x00\x03abcefg"), Ok((&b"efg"[..], &b"abc"[..])));
assert_eq!(parser(b"\x00\x03123123"), Err(Err::Error(Error::new(&b"123"[..], ErrorKind::Tag))));
assert_eq!(parser(b"\x00\x03a"), Err(Err::Incomplete(Needed::new(2))));