use std::ops::Index;

struct PaddedVec<T: Clone> {
    zero_offset: usize,
    buffer: Vec<T>,
}

impl<T: Clone> PaddedVec<T> {
    fn new(size: usize, padding: usize, init: T) -> PaddedVec<T> {
        let v = vec![init; size + 2 * padding];
        PaddedVec {
            zero_offset: padding,
            buffer: v,
        }
    }
}

impl<T: Clone> Index<isize> for PaddedVec<T> {
    type Output = T;

    fn index(&self, index: isize) -> &T {
        let i: usize = ((self.zero_offset as isize) + index) as usize;
        &self.buffer[i]
    }
}

fn main() {
    let v = PaddedVec::new(100, 10, 1usize);

}