cast

extern crate cast;

// `u8` and `u16` are checked cast functions, use them to cast from any numeric
// primitive to `u8`/`u16` respectively
use cast::{u8, u16, Error};

// Infallible operations, like integer promotion, are equivalent to a normal
// cast with `as`
assert_eq!(u16(0u8), 0u16);

// Everything else will return a `Result` depending on the success of the
// operation
assert_eq!(u8(0u16), Ok(0u8));
assert_eq!(u8(256u16), Err(Error::Overflow));
assert_eq!(u8(-1i8), Err(Error::Underflow));
assert_eq!(u8(1. / 0.), Err(Error::Infinite));
assert_eq!(u8(0. / 0.), Err(Error::NaN));