shrceil.rs

use std::ops::{Shr,Neg};
use std::marker::Sized;

trait ShrCeil<Rhs=Self>
{
    type Output;

    fn shr_ceil(self, rhs: Rhs) -> Self::Output;
}

impl<Rhs, Lhs> ShrCeil<Rhs> for Lhs
    where
        Lhs: Neg + Sized,
        <Lhs as Neg>::Output: Shr<Rhs>,
        <<Lhs as Neg>::Output as Shr<Rhs>>::Output: Neg,
{
    type Output = <<<Lhs as Neg>::Output as Shr<Rhs>>::Output as Neg>::Output;

    fn shr_ceil(self, rhs: Rhs) -> Self::Output {
        -((-self) >> rhs)
    }
}

#[test]
fn shr_ceil_i8_odd() {
    assert_eq!(3i8.shr_ceil(1), 2i8)
}

#[test]
fn shr_ceil_i8_even() {
    assert_eq!(4i8.shr_ceil(1), 2i8)
}