1//! Just like [`Cell`] but with [volatile] read / write operations
2//!
3//! [`Cell`]: https://doc.rust-lang.org/std/cell/struct.Cell.html
4//! [volatile]: https://doc.rust-lang.org/std/ptr/fn.read_volatile.html
5
6#![deny(missing_docs)]
7#![deny(warnings)]
8#![no_std]
9
10use core::cell::UnsafeCell;
11use core::ptr;
12
13/// Just like [`Cell`] but with [volatile] read / write operations
14///
15/// [`Cell`]: https://doc.rust-lang.org/std/cell/struct.Cell.html
16/// [volatile]: https://doc.rust-lang.org/std/ptr/fn.read_volatile.html
17#[repr(transparent)]
18pub struct VolatileCell<T> {
19 value: UnsafeCell<T>,
20}
21
22impl<T> VolatileCell<T> {
23 /// Creates a new `VolatileCell` containing the given value
24 pub const fn new(value: T) -> Self {
25 VolatileCell { value: UnsafeCell::new(value) }
26 }
27
28 /// Returns a copy of the contained value
29 #[inline(always)]
30 pub fn get(&self) -> T
31 where T: Copy
32 {
33 unsafe { ptr::read_volatile(self.value.get()) }
34 }
35
36 /// Sets the contained value
37 #[inline(always)]
38 pub fn set(&self, value: T)
39 where T: Copy
40 {
41 unsafe { ptr::write_volatile(self.value.get(), value) }
42 }
43
44 /// Returns a raw pointer to the underlying data in the cell
45 #[inline(always)]
46 pub fn as_ptr(&self) -> *mut T {
47 self.value.get()
48 }
49}
50
51// NOTE implicit because of `UnsafeCell`
52// unsafe impl<T> !Sync for VolatileCell<T> {}
53