use std::convert::TryInto;
pub trait ReadInteger<T> {
    fn from_le_bytes(data: &[u8]) -> T;
    fn from_be_bytes(data: &[u8]) -> T;
}

macro_rules! impl_read_integer {
    ($($t:ty),+) => {
        $(impl ReadInteger<$t> for $t {
            fn from_le_bytes(data: &[u8]) -> $t {
                <$t>::from_le_bytes(data.try_into().unwrap())
            }
            fn from_be_bytes(data: &[u8]) -> $t {
                <$t>::from_be_bytes(data.try_into().unwrap())
            }
        })+
    }
}

impl_read_integer!(u8, i16, i32, u32, i64);

fn read_integer<T: ReadInteger<T>>(data: &[u8]) -> T {
    T::from_le_bytes(&data[..std::mem::size_of::<T>()])
}
fn main(){
let slice = &[1,2,0,0];
let int1 = read_integer::<i32>(slice);
println!("{}",int1);
println!("{}",u32::from_le_bytes([1,2,0,0]));
}