Function rocket::mtls::x509::der_parser::asn1_rs::nom::bits::complete::take

source · 
pub fn take<I, O, C, E>(count: C) -> impl Fn((I, usize))
where
    E: ParseError<(I, usize)>,
    I: Slice<RangeFrom<usize>> + InputIter<Item = u8> + InputLength,
    C: ToUsize,
    O: From<u8> + AddAssign + Shl<usize, Output = O> + Shr<usize, Output = O>,
Available on crate feature mtls only.
Expand description

Generates a parser taking count bits

§Example

// Input is a tuple of (input: I, bit_offset: usize)
fn parser(input: (&[u8], usize), count: usize)-> IResult<(&[u8], usize), u8> {
 take(count)(input)
}

// Consumes 0 bits, returns 0
assert_eq!(parser(([0b00010010].as_ref(), 0), 0), Ok((([0b00010010].as_ref(), 0), 0)));

// Consumes 4 bits, returns their values and increase offset to 4
assert_eq!(parser(([0b00010010].as_ref(), 0), 4), Ok((([0b00010010].as_ref(), 4), 0b00000001)));

// Consumes 4 bits, offset is 4, returns their values and increase offset to 0 of next byte
assert_eq!(parser(([0b00010010].as_ref(), 4), 4), Ok((([].as_ref(), 0), 0b00000010)));

// Tries to consume 12 bits but only 8 are available
assert_eq!(parser(([0b00010010].as_ref(), 0), 12), Err(nom::Err::Error(Error{input: ([0b00010010].as_ref(), 0), code: ErrorKind::Eof })));