#![feature(test)]

fn main() {
    println!("Hello, world!");
}

#[cfg(test)]
mod tests {
    extern crate test;
    use self::test::Bencher;

    fn return_impl(n: usize) -> impl Iterator<Item = usize> { (0..n) }

    fn boxed_iter(n: usize) -> Box<Iterator<Item = usize>> { return Box::new(0..n); }

    fn make_vec(n: usize) -> Vec<usize> { (0..n).collect() }

    #[bench]
    fn bench_return_impl(b: &mut Bencher) {
        b.iter(|| {
            let n = test::black_box(100000);
            let mut a = 0;
            return_impl(n).for_each(|x| a ^= x);
            a
        })
    }

    #[bench]
    fn bench_boxed(b: &mut Bencher) {
        b.iter(|| {
            let n = test::black_box(100000);
            let mut a = 0;
            boxed_iter(n).for_each(|x| a ^= x);
            a
        })
    }

    #[bench]
    fn bench_vec(b: &mut Bencher) {
        b.iter(|| {
            let n = test::black_box(100000);
            let mut a = 0;
            make_vec(n).into_iter().for_each(|x| a ^= x);
            a
        })
    }
}