use nom7::{
bytes::streaming::{take, take_until},
combinator::map_res,
IResult,
};
use std;
fn parse_len(input: &str) -> Result<u32, std::num::ParseIntError> {
input.parse::<u32>()
}
pub fn parse_message(i: &[u8]) -> IResult<&[u8], String> {
let (i, len) = map_res(map_res(take_until(":"), std::str::from_utf8), parse_len)(i)?;
let (i, _sep) = take(1_usize)(i)?;
let (i, msg) = map_res(take(len as usize), std::str::from_utf8)(i)?;
let result = msg.to_string();
Ok((i, result))
}
#[cfg(test)]
mod tests {
use super::*;
use nom7::Err;
#[test]
fn test_parse_valid() {
let buf = b"12:Hello World!4:Bye.";
let result = parse_message(buf);
match result {
Ok((remainder, message)) => {
assert_eq!(message, "Hello World!");
assert_eq!(remainder.len(), 6);
}
Err(Err::Incomplete(_)) => {
panic!("Result should not have been incomplete.");
}
Err(Err::Error(err)) | Err(Err::Failure(err)) => {
panic!("Result should not be an error: {:?}.", err);
}
}
}
}