Checked

Implements a wrapper over the primitive Rust types that better indicates overflow during arithmetic.

The struct Checked is actually a wrapper over an Option, so if x is a Checked object, then x.0 can be used like an Option.

Example

extern crate checked
use checked::Checked;

fn main() {
    let x = Checked::from(1_000_000_000_u32) * 3 + 2_000_000_000;
    match x.0 {
        Some(y) => println!("Didn't overflow: x is {}.", y),
        None => println!("The arithmetic overflowed."),
    }
}

Note that Add<T> is implemented for Checked<T> for all the primitive integer types T (u8, i16, etc.) so really, only the left-most integer needs to be a Checked object. Once the arithmetic hits a Checked<T> on the right OR left, all the remaining results are Checked too. Just make sure there's a Checked somewhere before the first potential overflow.

This struct is based on std::num::Wrapping, except using checked arithmetic instead of wrapped arithmetic.

Contributing

I may try to add more features in time: make an Issue or Pull request to get the ball rolling.