macro_rules! validate {
($a:expr) => { if !$a { println!("check failed at {}:{}", file!(), line!()); return Err(DecoderError::InvalidData); } };
}
macro_rules! validate {
($a:expr) => { if !$a { println!("check failed at {}:{}", file!(), line!()); return Err(DecoderError::InvalidData); } };
}