From f524b3c3a55fc2dc60d7301b34e02a4e7cd94207 Mon Sep 17 00:00:00 2001
From: Intege-rs <me@jessiep.me>
Date: Sat, 16 Nov 2024 20:36:41 -0500
Subject: [PATCH] add the Mut<> type

---
 sub/core/src/lib.rs |  2 +-
 sub/core/src/pod.rs | 32 +++++++++++++++++++++++++++++++-
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/sub/core/src/lib.rs b/sub/core/src/lib.rs
index be64942..bf11b8d 100644
--- a/sub/core/src/lib.rs
+++ b/sub/core/src/lib.rs
@@ -50,7 +50,7 @@ pub mod prelude {
     pub use crate::time::dur;
     pub use crate::fnv1::*;
     pub use crate::pstruct::struct_offset;
-    pub use crate::pod::Pod;
+    pub use crate::pod::{Pod,Mut};
 }
 
 pub mod public {
diff --git a/sub/core/src/pod.rs b/sub/core/src/pod.rs
index 0e1f4d4..9e3be71 100644
--- a/sub/core/src/pod.rs
+++ b/sub/core/src/pod.rs
@@ -1,4 +1,5 @@
 use core::mem::MaybeUninit;
+use core::ops::{Deref, DerefMut};
 
 /// Plain Old data type
 pub trait Pod: Copy + 'static {
@@ -17,4 +18,33 @@ primitive!(i8, i16, i32, i64, i128);
 primitive!(f32, f64, usize, isize);
 primitive!(());
 
-impl<const LEN: usize, T: Pod> Pod for [T;LEN] {}
\ No newline at end of file
+impl<const LEN: usize, T: Pod> Pod for [T;LEN] {}
+
+
+/// Type with unsafe interior mutability
+/// but also with Send+Sync
+///
+/// internally just wraps UnsafeCell
+#[repr(transparent)]
+pub struct Mut<T>(core::cell::UnsafeCell<T>);
+unsafe impl<T> Sync for Mut<T> {}
+unsafe impl<T> Send for Mut<T> {}
+
+impl<T: Sized> Mut<T> {
+    pub const fn new(value: T) -> Self {
+        Self(core::cell::UnsafeCell::new(value))
+    }
+    pub const fn as_ptr(&self) -> *mut T {
+        self.0.get()
+    }
+}
+
+impl<T: Pod> Mut<T> {
+    pub fn set(&self, value: T) { unsafe { core::ptr::write(self.as_ptr(), value) } }
+    pub fn get(&self) -> T { unsafe { core::ptr::read(self.as_ptr()) } }
+}
+
+impl<T> Deref for Mut<T> {
+    type Target = core::cell::UnsafeCell<T>;
+    fn deref(&self) -> &Self::Target { &self.0 }
+}
\ No newline at end of file