lines.rs

pub struct Lines<'a> {
    bytes: &'a [u8],
}

impl<'a> Iterator for Lines<'a> {
    type Item = &'a [u8];

    fn next(&mut self) -> Option<Self::Item> {
        self.bytes.take_line()
    }
}

impl<'a> std::iter::FusedIterator for Lines<'a> {}

pub trait IntoLines {
    fn 行(&self) -> Lines<'_>;
}

impl<T: AsRef<[u8]>> IntoLines for T {
    fn 行(&self) -> Lines<'_> {
        Lines {
            bytes: self.as_ref(),
        }
    }
}

pub trait TakeLine<'b> {
    fn take_line<'a>(&'a mut self) -> Option<&'b [u8]>;
}

impl<'b> TakeLine<'b> for &'b [u8] {
    fn take_line<'a>(&'a mut self) -> Option<&'b [u8]> {
        match memchr::memchr(b'\n', self) {
            None if self.is_empty() => None,
            None => {
                let line = *self;
                *self = b"";
                Some(line)
            }
            Some(end) => {
                let line = &self[..end];
                *self = &self[end + 1..];
                Some(line)
            }
        }
    }
}

impl<'b> TakeLine<'b> for &'b str {
    fn take_line<'a>(&'a mut self) -> Option<&'b [u8]> {
        match memchr::memchr(b'\n', self.as_bytes()) {
            None if self.is_empty() => None,
            None => {
                let line = self.as_bytes();
                *self = "";
                Some(line)
            }
            Some(end) => {
                let line = self[..end].as_bytes();
                *self = &self[end + 1..];
                Some(line)
            }
        }
    }
}