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use std::io::{self, BufRead};
const LINE_FEED: char = '\n';
const CARRIAGE_RETURN: char = '\r';
#[derive(Debug)]
pub struct Reader<R> {
inner: R,
}
impl<R> Reader<R>
where
R: BufRead,
{
pub fn new(inner: R) -> Self {
Self { inner }
}
pub fn read_record(&mut self, buf: &mut String) -> io::Result<usize> {
read_line(&mut self.inner, buf)
}
}
fn read_line<R>(reader: &mut R, buf: &mut String) -> io::Result<usize>
where
R: BufRead,
{
match reader.read_line(buf) {
Ok(0) => Ok(0),
Ok(n) => {
if buf.ends_with(LINE_FEED) {
buf.pop();
if buf.ends_with(CARRIAGE_RETURN) {
buf.pop();
}
}
Ok(n)
}
Err(e) => Err(e),
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_read_line() -> io::Result<()> {
let mut buf = String::new();
let data = b"noodles\n";
let mut reader = &data[..];
buf.clear();
read_line(&mut reader, &mut buf)?;
assert_eq!(buf, "noodles");
let data = b"noodles\r\n";
let mut reader = &data[..];
buf.clear();
read_line(&mut reader, &mut buf)?;
assert_eq!(buf, "noodles");
let data = b"noodles";
let mut reader = &data[..];
buf.clear();
read_line(&mut reader, &mut buf)?;
assert_eq!(buf, "noodles");
Ok(())
}
}