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use crate::{eyre, Buffer, Parse};
#[derive(Debug, Copy, Clone, PartialEq)]
pub struct Tag<const TAG: &'static [u8]>;
impl<const TAG: &'static [u8]> Parse<u8> for Tag<TAG> {
fn parse(input: &mut impl Buffer<u8>) -> eyre::Result<Self> {
let b: Vec<u8> = input.take(TAG.len()).collect();
if TAG == b {
Ok(Self)
} else {
Err(eyre::eyre!("failed to parse tag {:?}, found {:?}", TAG, b))
}
}
fn peek(input: &mut impl Buffer<u8>) -> bool {
TAG.iter().cloned().eq(input.take(TAG.len()))
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::{parse, IntoBuf, Parse};
#[test]
fn test_parse_matches() {
let mut input = "(){}[]<>".bytes().into_buf();
Tag::<b"(">::parse(&mut input).unwrap();
Tag::<b")">::parse(&mut input).unwrap();
Tag::<b"{">::parse(&mut input).unwrap();
Tag::<b"}">::parse(&mut input).unwrap();
Tag::<b"[">::parse(&mut input).unwrap();
Tag::<b"]">::parse(&mut input).unwrap();
Tag::<b"<">::parse(&mut input).unwrap();
Tag::<b">">::parse(&mut input).unwrap();
assert!(input.next().is_none())
}
#[test]
fn test_parse_errors() {
let res: Result<Tag<b"(">, _> = parse("1".bytes());
assert_eq!(
format!("{}", res.unwrap_err()),
"failed to parse tag [40], found [49]"
);
let res: Result<Tag<b")">, _> = parse("1".bytes());
assert_eq!(
format!("{}", res.unwrap_err()),
"failed to parse tag [41], found [49]"
);
}
}