From a93a4ca1867efd857aeb3a82e3c192b020097fdf Mon Sep 17 00:00:00 2001
From: Per Lindgren <per.lindgren@ltu.se>
Date: Fri, 2 Apr 2021 16:14:00 +0200
Subject: [PATCH] with error
---
src/main.rs | 97 +++++++++++++++++++++++++++++++++++++++++++----------
1 file changed, 79 insertions(+), 18 deletions(-)
diff --git a/src/main.rs b/src/main.rs
index fb3a7bd..bf3864e 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -22,6 +22,11 @@ impl<T> RacyCell<T> {
//unsafe impl<T> Sync for RacyCell<T> where T: Sync {}
unsafe impl<T> Sync for RacyCell<T> {}
+#[derive(Debug)]
+enum Error {
+ Unitialized,
+ OutOfMemory,
+}
struct Box<T: 'static + Sized, const S: usize> {
// data: &'static mut T,
index: usize,
@@ -30,21 +35,30 @@ struct Box<T: 'static + Sized, const S: usize> {
impl<T: 'static, const S: usize> Drop for Box<T, S> {
fn drop(&mut self) {
- self.allocator.dealloc(self.index)
+ unsafe { self.allocator.dealloc(self.index) }
}
}
impl<T: 'static, const S: usize> Deref for Box<T, S> {
type Target = T;
fn deref(&self) -> &T {
- unsafe { &self.allocator.data.get_mut_unchecked()[self.index] }
+ unsafe {
+ self.allocator
+ .data /* RacyCell */
+ .get_mut_unchecked() /* Array */
+ .get_unchecked(self.index)
+ }
}
}
impl<T: 'static, const S: usize> DerefMut for Box<T, S> {
- // type Target = T;
fn deref_mut(&mut self) -> &mut T {
- unsafe { &mut self.allocator.data.get_mut_unchecked()[self.index] }
+ unsafe {
+ self.allocator
+ .data /* RacyCell */
+ .get_mut_unchecked() /* Array */
+ .get_unchecked_mut(self.index)
+ }
}
}
@@ -72,6 +86,9 @@ where
}
fn init(&self) {
+ if *unsafe { self.init.get_mut_unchecked() } {
+ panic!("already initialized")
+ };
let free = unsafe { self.free.get_mut_unchecked() };
for (index, value) in free.iter_mut().enumerate() {
*value = index + 1;
@@ -81,30 +98,31 @@ where
println!("init : free {:?}", unsafe { self.free.get_mut_unchecked() });
}
- fn dealloc(&self, index: usize) {
- unsafe {
- if !*self.init.get_mut_unchecked() {
- panic!();
- }
- self.free.get_mut_unchecked()[index] = *self.head.get_mut_unchecked();
- *self.head.get_mut_unchecked() = index;
- }
+ // dealloc can only be called by dropping Box
+ // which can happen only if already initialized
+ // in a library we could hide this as a crate local
+ unsafe fn dealloc(&self, index: usize) {
+ self.free.get_mut_unchecked()[index] = *self.head.get_mut_unchecked();
+ *self.head.get_mut_unchecked() = index;
+
println!("dealloc index {}", index)
}
- fn alloc(&'static self) -> Result<Box<T, S>, ()> {
+ fn alloc(&'static self) -> Result<Box<T, S>, Error> {
unsafe {
if !*self.init.get_mut_unchecked() {
- panic!();
+ return Err(Error::Unitialized);
}
let index = *self.head.get_mut_unchecked();
println!("index {}", self.head.get_mut_unchecked());
println!("head {}", self.head.get_mut_unchecked());
- *self.head.get_mut_unchecked() = self.free.get_mut_unchecked()[index];
- println!("new head {}", self.head.get_mut_unchecked());
- if *self.head.get_mut_unchecked() > S {
- Err(())
+ if *self.head.get_mut_unchecked() >= S {
+ Err(Error::OutOfMemory)
} else {
+ *self.head.get_mut_unchecked() =
+ *self.free.get_mut_unchecked().get_unchecked_mut(index);
+ println!("new head {}", self.head.get_mut_unchecked());
+
Ok(Box {
index,
allocator: self,
@@ -114,6 +132,49 @@ where
}
}
+mod tests {
+ use super::*;
+ static P: PoolMan<u32, 2> = PoolMan::new([0; 2]);
+
+ #[test]
+ fn test() {
+ P.init();
+ {
+ let e = P.alloc().unwrap();
+ println!("e {}", *e);
+ mem::drop(e);
+ let mut e1 = P.alloc().unwrap();
+ println!("e1 {}", *e1);
+ *e1 = 2;
+ println!("e1 {}", *e1);
+
+ let e2 = P.alloc().unwrap();
+ println!("e2 {}", *e2);
+ }
+ let e = P.alloc().unwrap();
+ println!("e {}", *e);
+ }
+
+ #[test]
+ fn test2() {
+ P.init();
+ {
+ let e = P.alloc().unwrap();
+ println!("e {}", *e);
+ mem::drop(e);
+ let mut e1 = P.alloc().unwrap();
+ println!("e1 {}", *e1);
+ *e1 = 2;
+ println!("e1 {}", *e1);
+
+ let e2 = P.alloc().unwrap();
+ println!("e2 {}", *e2);
+ }
+ let e = P.alloc().unwrap();
+ println!("e {}", *e);
+ }
+}
+
static P: PoolMan<u32, 2> = PoolMan::new([0; 2]);
fn main() {
P.init();
--
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