use std::cell::Cell;

/*
#[derive(Debug,Copy,Clone)]
struct Locker (u32);

impl Locker {
    fn lock(self) -> u32 {
       self.0
    }
}
*/

#[derive(Debug)]
struct Peripherals {
    serial1: Cell<u32>,
    serial2: Cell<u32>
}

impl Peripherals {
    fn take_serial(&self, idx: usize) -> u32 {
        match idx {
            0 => self.serial1.replace(0),
            _ => self.serial2.replace(0)
        }
    }
}

//static mut SERIAL1: Locker = Locker(1);
//static mut SERIAL2: Locker = Locker(2);
fn main() {
/*static*/ let PERIPHERALS: Peripherals = Peripherals {
    serial1: Cell::new(1),
    serial2: Cell::new(2)
};

//fn main() {
    println!("PERIPHERALS:{:?}", unsafe { &PERIPHERALS });
    let s1 = PERIPHERALS.take_serial(0);
    let s2 = PERIPHERALS.take_serial(1);
    println!("s1:{}, s2:{}", s1, s2);
    println!("PERIPHERALS:{:?}", unsafe { &PERIPHERALS });
}

/*
fn foo() -> u32 {
    unsafe { PERIPHERALS.take_serial(0) }
}

fn bar() -> u32 {
    unsafe { PERIPHERALS.take_serial(0) }
}
*/