realloc 0.1.1

A re-implementation of various ::alloc features
Documentation 
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use core::cell::UnsafeCell;
use core::ops::{Deref, DerefMut};
use core::sync::atomic::{AtomicBool, Ordering};

pub(crate) struct Mutex<T> {
    data: UnsafeCell<T>,
    lock: AtomicBool,
}

impl<T> Mutex<T> {
    pub const fn new(data: T) -> Self {
        Self {
            data: UnsafeCell::new(data),
            lock: AtomicBool::new(false),
        }
    }

    pub fn get_mut(&mut self) -> &mut T {
        debug_assert!(!*self.lock.get_mut());
        self.data.get_mut()
    }

    pub fn lock(&self) -> Lock<'_, T> {
        while self.lock.swap(true, Ordering::SeqCst) {
            core::hint::spin_loop();
        }

        Lock(self)
    }
}

pub(crate) struct Lock<'mutex, T>(&'mutex Mutex<T>);

impl<T> Deref for Lock<'_, T> {
    type Target = T;

    fn deref(&self) -> &T {
        // SAFETY: the atomic lock guarantees nobody else can see it
        unsafe { &*self.0.data.get() }
    }
}

impl<T> DerefMut for Lock<'_, T> {
    fn deref_mut(&mut self) -> &mut T {
        // SAFETY: the atomic lock guarantees nobody else can see it
        unsafe { &mut *self.0.data.get() }
    }
}

impl<T> Drop for Lock<'_, T> {
    fn drop(&mut self) {
        self.0.lock.store(false, Ordering::SeqCst);
    }
}

unsafe impl<T> Sync for Mutex<T> {}