rust_getc.rs

/// 1文字読む．
/// let c = getc(&mut std::io::stdin()).unwrap();
fn getc(r : &mut Read) -> Result<u8, Error>{
    let mut buf = [0;1];
    match r.read(&mut buf){
        Ok(size) => { if size > 0 { Ok(buf[0]) } else { Err(Error::new(ErrorKind::Other, "no out") ) } }
        Err(err) => { Err(err) }
    }
}
#[test]
fn test_getc() {
    let text = "ab";
    let mut buf = std::io::BufReader::new(text.as_bytes());
    assert_eq!(97, getc(&mut buf).unwrap());
    assert_eq!(98, getc(&mut buf).unwrap());
    assert_eq!(true, getc(&mut buf).is_err());
}