use std::io;

pub trait ReadExt: io::Read {
    fn read_max(&mut self, mut buf: &mut [u8]) -> io::Result<usize> {
        let start_len = buf.len();
        while !buf.is_empty() {
            match self.read(buf) {
                Ok(0) => break,
                Ok(n) => { let tmp = buf; buf = &mut tmp[n..]; }
                Err(ref e) if e.kind() == io::ErrorKind::Interrupted => {}
                Err(e) => return Err(e),
            }
        }

        Ok(start_len - buf.len())
    }
}

impl<T: io::Read> ReadExt for T {  }